Universiti Teknologi Malaysia Institutional Repository: No conditions. Results ordered -Date Deposited.
2020-09-21T09:43:40Z
EPrints
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http://eprints.utm.my/id/eprint/
2018-08-26T11:54:48Z
2018-08-26T11:54:48Z
http://eprints.utm.my/id/eprint/id/eprint/78414
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/78414
2018-08-26T11:54:48Z
Synthesis and characterization of aluminum doped zinc oxide nanowires on non-catalytic silica substrates
The undoped and Al-doped ZnO nanostructures were fabricated on the Si (100) substrates via catalyst free thermal evaporation method using a horizontal quartz tube under controlled supply of O2 gas. The substrate was placed vertically above the source materials unlike the conventional methods. The undoped ZnO nanowires were randomly oriented. When both Al dopant and when doping concentrations were increased, ZnO showed various morphologies in which ZnO changed from randomly orientated nanowires to hexagonal shaped, ‘pencil-like’ nanorods. Further increase in dopant concentrations beyond 2.4 at% lead to spikey ZnO:Al morphology. The morphology and crystalline structure of ZnO nanostructures were characterized using X-ray diffraction, field emission scanning electron microscopy, scanning electron microscopy and photoluminescence (PL) spectroscopy. ZnO:Al nanorods were found to have diameter roughly between 260 to 350 nm and the length about 720 nm. The as prepared ZnO:Al nanorods also exhibited a strong UV emission. The Al doping concentrations played an important role on the morphology and optical properties of ZnO nanostructures. The significance of the experiment is the simplicity, low cost and fewer necessary apparatus of the process that would suit the high-throughput fabrication of ZnO:Al nanorods. They are expected to have potential applications in functional Si based nanodevices.
Tashi Dorji
2018-08-26T11:51:48Z
2018-08-26T11:51:48Z
http://eprints.utm.my/id/eprint/id/eprint/78323
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/78323
2018-08-26T11:51:48Z
Genetic algorithm approach in solving minisum facility location problem with fixed line barrier
Facility location problem is a field of study in Operational Research that required in considering locating a facility or a set of new facilities on the plane to serve a finite set of existing demand points. A facility location problem usually formulated as a minimization or maximization problem with an objective function involving distances between the facility and demand points. Generally, facility location problems can be classified into several problems. However in this study, minisum facility location problem involving fixed line barrier is considered since line barrier is the most applicable one in real life problem. This is because the line barrier such as rivers, highways, borders or mountain ranges are frequently encountered in practice or real problem. The main objective of this study is to concentrate on solving the minisum facility location problem with fixed line barrier using meta-heuristic approach namely as Genetic Algorithm (GA). The basic concepts of facility location with barrier as well as formulation of the problem are also had been discussed in this study. Subsequently, the developed genetic algorithm for solving the problem is proposed in this study. The procedure is coded using C++ programming and implemented on generated data of 50 fixed points.
Nurfarhani Mohd. Shabri
2018-07-25T08:19:06Z
2018-07-25T08:19:06Z
http://eprints.utm.my/id/eprint/id/eprint/78174
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/78174
2018-07-25T08:19:06Z
Optimal placement of security camera
This research studies the optimization on the placement of security camera. We need to improve the field of view (FOV) coverage of a security camera by only adjusting the location of cameras with minimal numbers of cameras. Two dimensional of floor plan was designed in boundary nodes and internal nodes. Cameras were installed at boundary node in order to view the internal nodes. We propose Binary Integer Programming method which can efficiently find an optimal layout for each camera. Heuristic method of Particle Swarm Optimization (PSO) algorithm is applied on this problem. As a result of this optimization, the FOV coverage of the whole camera network is maximized. This study show that the proposed PSO method perform well and effectively applied in placement of security camera on any design of floor plan.
Li Chin Lee
2018-07-25T08:19:00Z
2018-07-25T08:19:00Z
http://eprints.utm.my/id/eprint/id/eprint/78166
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/78166
2018-07-25T08:19:00Z
Broyden’s and Thomas’ methods for identifying singular roots in nonliner systems
Nonlinear systems is one of the mathematical models that is commonly used in the engineering and science fields and it is quite complicated to determine the root especially when the problem is singular. This study is conducted in order to study the performance of Broyden’s and Thomas’ method, which are parts of Quasi-Newton method in solving singular nonlinear systems. By applying the algorithm of each methods, we conduct the calculation to achieve the approximate solutions. MATLAB software is used to compute and present the solutions. Some of useful test problems would describe the properties and usage of the methods. Hence, both methods that have been considered in this study give well approximate solution but Thomas’ method gives better results than Broyden’s method.
Ikka Afiqah Amir
2018-07-25T08:18:57Z
2018-07-25T08:18:57Z
http://eprints.utm.my/id/eprint/id/eprint/78155
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/78155
2018-07-25T08:18:57Z
Optimization of reaction conditions on titanium dioxide with various co-catalysts for phenol removal
Titanium oxide, TiO2 is commonly used as a photocatalyst for photocatalytic degradation of organic pollutants such as phenol. In order to improve the photocatalytic efficiency of TiO2, modification and reaction condition optimizations were carried out in this study. Three types of TiO2 were used, which were anatase, rutile, and mixture of anatase and rutile. It was confirmed that the anatase structure gave the highest photocatalytic activity with 22% of phenol removal after 2 hours reaction under UV light irradiation. Modification of anatase TiO2 was conducted using various co-catalysts, such as Pt, Ni, ZnO, and Fe2O3. Among the examined cocatalysts, only Pt showed its potential as co-catalyst for TiO2 in this photocatalyst system. The Pt/TiO2 series were then characterized by X-ray diffraction (XRD), particle size analyser, Diffuse Reflectance UV-Visible spectroscopy (DR UVVisible), and fluorescence spectroscopy. XRD patterns showed that the addition of Pt resulted in the higher peak intensity of the TiO2, without detection of other diffraction peaks. This result suggested that the addition of Pt might induce the high crystallinity and increase the particle size of prepared samples. The increase of the particle size was in good agreement with the particle size distribution. DR UVvisible spectra showed the strong absorption peak of TiO2 at 320 nm, indicating that all of these samples possess the ability to be active in UV light region. Additional of absorbance at background level above 400 nm suggested the presence of Pt in the Pt/TiO2 samples. Fluorescence spectra showed that the emission intensity of TiO2 increased with the addition of Pt, suggesting the Pt can act as an electron trapper. The effect of co-catalyst loading on TiO2 anatase was then investigated and it was found that 0.5 wt% loading on TiO2 gave higher photocatalytic phenol removal (28%) than the unmodified TiO2. Optimization of the reaction conditions was carried out by varying the amount of catalyst, pH of the solution, and addition of H2O2 into the phenol solution. It was observed that the best condition for the Pt/TiO2 to give the highest activity (54%) was obtained when using 50 mg of catalyst, phenol solution pH of 6.4 and ratio of H2O2 to phenol solution of 10.5. The kinetic study showed that the reactions followed first order reaction and the rate of reaction increased with the addition of H2O2 under optimized conditions.
Herlin Noorain Danuri
2018-04-12T05:41:19Z
2018-04-12T05:41:19Z
http://eprints.utm.my/id/eprint/id/eprint/38022
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38022
2018-04-12T05:41:19Z
An improved two-step method in stochastic differential equation's structural parameter estimation
Non-parametric modelling is a method which relies heavily on data and motivated by the smoothness properties in estimating a function which involves spline and non-spline approaches. Spline approach consists of regression spline and smoothing spline. Regression spline characterised by the truncated power series basis with Bayesian approach is considered in the first step of a two-step method for estimating the structural parameters for stochastic differential equation (SDE). Previous methodology revealed the selection of knot and order of spline can be done heuristically based on a scatter plot. To overcome the subjective and tedious process of selecting the optimal knot and order of spline, an algorithm is proposed. A single optimal knot is selected out of all the points with exception of the first and the last data and the least value of Generalised Cross Validation is calculated for each order of spline. The spline model is later utilised in the second step to estimate the stochastic model parameters. In the second step, a non-parametric criterion is proposed for estimating the diffusion parameter of SDE. Linear and non-linear SDE consisting of Geometric Brownian Motion (GBM) for the former and logistic together with Lotka Volterra (LV) model for the later are tested using the two-step method for both simulated and real data. The results show high percentage of accuracy with 99.90% and 96.12% are obtained for GBM and LV model respectively for diffusion parameters of simulated data. This verifies the viability of the two-step method in the estimation of diffusion parameters of SDE with an improvement of a single knot selection.
Haliza Abd. Rahman
2018-04-12T05:40:33Z
2018-04-12T05:40:33Z
http://eprints.utm.my/id/eprint/id/eprint/38015
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38015
2018-04-12T05:40:33Z
Fabrication of periodic microstructures on glass and polymer using low power CO2 laser
Micromachining on glass and polymers has been a widely attractive approach during the past few decades. In laser micromachining of materials, carbon dioxide (CO2) laser is one of the most significant lasers used. This thesis describes direct laser writing (DLW) scheme for the fabrication of periodic structures on glass and polymers. The periodic structures are important components in diffractive optics and microfluidic devices. The DLW technology is a modern day machining tool which helps to experimentally investigate the behavior of high power lasers on glass and polymers without lithographic and mask-based techniques. The DLW scheme gives great advantages, making it an efficient and cost effective approach for inducing periodic structures. The experimental observations in this research have urged the use of low power (2.5 W) CO2 laser irradiation to obtain narrow and fine patterns. The laser power and scanning speed play a vital role in the fabrication process. The current investigation focuses on glass and acrylic for the generation of regular and tidy periodic structures. The whole DLW process is controlled by a computer software program. The structure to be written by the laser is first coded and input into the CAD software, before being written on an actual workpiece. The Gaussian CO2 laser beam with a maximum power of 2.5 W has been targeted to the workpiece which is placed on the moveable xy translational stage. The laser power used in this process ranged from 1 to 2.5 W and the scanning speed, from 0 to 5 mm/s. A scanning electron microscope (SEM), an optical microscope and a surface profiler were used for observing the surface morphology and the channel cross section. A 632.8 nm HeNe laser was used for observing diffraction patterns of the fabricated periodic structures. The formation of periodic structures depends on laser power and scanning speed. The depth and width of the formed channels for glass ranged from 35 to 45 µm and from 15 to 25 µm, respectively. This research has shown the potential to fabricate periodic structures with a period of 1.5 µm which is less than the laser wavelength of 10.6 µm. These results were analyzed using a high precision, non-contact surface profiler technique developed by Taicaan, United Kingdom. In the case of polymethyl methacrylate (PMMA), the depth of the channels increases with increasing laser power, reaching a maximum value of 2349 µm at a laser power of 2.5 W. The formed structure exhibits the properties of diffraction gratings and hence can be used for diffraction experiments. The direct laser writing technique for the formation of microstructures, proves to be an efficient and effective method. A model for heat transfer inside the material is developed using the COMSOL Multiphysics software. Results from the simulated model give the temperature distribution inside the workpiece and are in good agreement with the experimental data obtained.
Imran Muhammad
2017-10-08T03:29:18Z
2017-10-08T03:29:18Z
http://eprints.utm.my/id/eprint/id/eprint/68564
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/68564
2017-10-08T03:29:18Z
The homological functor of a Bieberbach group with a cyclic point group of order two
The generalized presentation of a Bieberbach group with cyclic point group of order two can be obtained from the fact that any Bieberbach group of dimension n is a direct product of the group of the smallest dimension with a free abelian group. In this paper, by using the group presentation, the homological functor of a Bieberbach group a with cyclic point group of order two of dimension n is found.
Hazzirah Izzati Mat Hassim
Nor Haniza Sarmin
Nor Muhainiah Mohd. Ali
Rohaidah Masri
Nor'ashiqin Mohd. Idrus
2017-10-08T03:28:46Z
2017-10-08T03:28:46Z
http://eprints.utm.my/id/eprint/id/eprint/68563
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/68563
2017-10-08T03:28:46Z
The generative power of weighted one-sided and regular sticker systems
Sticker systems were introduced in 1998 as one of the DNA computing models by using the recombination behavior of DNA molecules. The Watson-Crick complementary principle of DNA molecules is abstractly used in the sticker systems to perform the computation of sticker systems. In this paper, the generative power of weighted one-sided sticker systems and weighted regular sticker systems are investigated. Moreover, the relationship of the families of languages generated by these two variants of sticker systems to the Chomsky hierarchy is also presented.
Yee Siang Gan
Wan Heng Fong
Nor Haniza Sarmin
Sherzod Turaev
2017-10-08T03:27:51Z
2017-10-08T03:27:51Z
http://eprints.utm.my/id/eprint/id/eprint/68561
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/68561
2017-10-08T03:27:51Z
The generalization of the exterior square of a Bieberbach group
The exterior square of a group is one of the homological functors which were originated in the homotopy theory. Meanwhile, a Bieberbach group is a torsion free crystallographic group. A Bieberbach group with cyclic point group of order two, C2, of dimension n can be defined as the direct product of that group of the smallest dimension with a free abelian group. Using the group presentation and commutator generating sequence, the exterior square of a Bieberbach group with point group C2 of dimension n is computed.
Rohaidah Masri
Hazzirah Izzati Mat Hassim
Nor Haniza Sarmin
Nor Muhainiah Mohd. Ali
Nor'ashiqin Mohd. Idrus
2017-10-08T03:27:23Z
2017-10-08T03:27:23Z
http://eprints.utm.my/id/eprint/id/eprint/68560
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/68560
2017-10-08T03:27:23Z
The formation of iron aluminides on aluminum surface by using a Q-switched Nd:YAG laser
The formation and growth of Fe based aluminum diffusion layers at the Fe-Al interface have been investigated to improve the surface hardness. The diffusion of Fe into Al has been accomplished by focusing a Q-switched Nd:YAG laser on the modified surface. The variety of the layer depth is achieved based on the type of heating and quenching media. Microstructural characterization and mechanical properties of the modified surface were carried out via gas discharge spectrometer GDS, X-Ray diffraction (XRD), Scanning electron microscope (SEM), and Vickers Hardness tester. The results indicate that hardness at the interface of Fe-Al layer is increased. The optimum hardness achieved as 93 HV at corresponding critical energy density of 438 Jcm-2.
Noriah Bidin
Yusef A. Al-Wafi
2017-08-30T05:55:25Z
2017-08-30T05:55:25Z
http://eprints.utm.my/id/eprint/id/eprint/33083
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33083
2017-08-30T05:55:25Z
Application of the runge-kutt discretization method on an optimal control problem
Haslinda Baharin
2017-08-30T04:57:04Z
2017-08-30T04:57:04Z
http://eprints.utm.my/id/eprint/id/eprint/33126
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33126
2017-08-30T04:57:04Z
Detection of chloramphenicol in chicken's serum and human's urine by spectroscopy
Zohreh Asadollahi
2017-08-14T07:16:51Z
2017-08-14T07:17:06Z
http://eprints.utm.my/id/eprint/id/eprint/32481
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/32481
2017-08-14T07:16:51Z
Removal of toxic and heavy metals from Anadara Granosa using chelating agents
Nurul Hazirah Mukhtar
2017-07-31T07:56:43Z
2017-07-31T08:05:11Z
http://eprints.utm.my/id/eprint/id/eprint/32320
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/32320
2017-07-31T07:56:43Z
Nonlinear evolutions equations in hirota's and sato's theories via young and maya diagrams
This work relates Hirota direct method to Sato theory. The bilinear direct
method was introduced by Hirota to obtain exact solutions for nonlinear evolution
equations. This method is applied to the Kadomtsev-Petviashvili (KP), KortewegdeVries
(KdV), Sawada-Kotera (S-K) and sine-Gordon (s-G) equations and solved to
generate multi-soliton solutions. The Hirota’s scheme is shown to link to the Sato
theory and later produced the Sato equation. It is also shown that the -function, which
underlies the form of the soliton solutions, acts as the key function to express the
solutions of the Sato equation. By using the results of group representation theory,
particularly via Young and Maya diagrams, it is shown that the -function is naturally
being governed by the class of physically significant nonlinear partial differential
equations in the bilinear forms of Hirota scheme and are closely related to the Plucker
relations. This framework is shown for Kadomtsev-Petviashvili (KP), KortewegdeVries
(KdV), Sawada-Kotera (S-K) and sine-Gordon (s-G) equations.
Noor Aslinda Ali
2017-07-23T10:12:10Z
2017-07-23T10:15:17Z
http://eprints.utm.my/id/eprint/id/eprint/34642
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/34642
2017-07-23T10:12:10Z
Markov chain analysis to detect water quality level
The quantificational analysis on progress of river water quality is important in knowing the dynamic change of water quality level. A mathematical model based on Markov chain is established in order to detect the water quality level in rivers. In this study, the level changes of water quality of River A, River B, River C and River D in 2010 based on water quality parameters of DO, BOD, COD, SS, pH and AN will be determined using Markov chain model. In order to determine the water quality level in rivers, the developing of the Markov chain model has to be conducted. There are three main steps in developing this model. The steps are establishing the transition probability matrix, calculate degree of absolute progress (DAP) and degree of relative progress (DRP).If the orders of water quality in rivers are arranged from the most deteriorated to the most improved, it will start from River B followed by River D, River A and River C. In other words, River B has the least improvement of changes among the rivers meanwhile River C has the most improvement of changes. After the Markov chain analysis to detect the water quality level has been done, the Water Quality Index (WQI) method is applied next in order to do justification of the Markov chain results. Surprisingly, the Markov chain model results match very well with the WQI method results when comparisons for both methods are made. To sum up, the results from Markov chain analysis can be justified by using the WQI method.
Nurul Nabihah Rahman
2017-07-12T07:47:15Z
2017-07-12T07:47:42Z
http://eprints.utm.my/id/eprint/id/eprint/32265
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/32265
2017-07-12T07:47:15Z
Mass transfer to blood flowing through arterial stenosis
Nurfathiah Mohammed
2017-07-11T07:29:35Z
2017-07-11T07:29:35Z
http://eprints.utm.my/id/eprint/id/eprint/62906
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/62906
2017-07-11T07:29:35Z
The effects of heat generation or absorption on MHD stagnation point of Jeffrey fluid
The analysis on the problem of heat generation/absorption effects on MHD stagnation point of Jeffrey Fluid is carried out. The governing partial differential equations are first transform as first order ordinary differential equation using similarity transformation before solving using numerical scheme called Keller-box. A comparative study with the previous results is made in order to verify the validation of the present results. The results for the skin friction and heat transfer coefficient as well as velocity and temperature profiles are presented and discussed in details for various values of heat generation/absorption parameter, magnetic parameter, Deborah number and Prandtl number.
Abdul Rahman Mohd. Kasim
Yeou Jiann Lim
Sharidan Shafie
Anati Ali
2017-06-20T02:04:50Z
2017-06-20T02:15:57Z
http://eprints.utm.my/id/eprint/id/eprint/33214
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33214
2017-06-20T02:04:50Z
Magnetohydrodynamics of blasius viscoelastic fluid with viscous dissipation and suction/injection effects
Due to the existence of viscoelastic fluid in technological applications, the research in the viscoelastic fluids has increase rapidly. In this study, the magnetohydrodynamics flow for the Blasius viscoelastic fluid along with the effects of viscous dissipation and suction or injection is considered. Since the equation of motion in viscoelastic fluid is one order higher than the Navier-Stokes or boundary layer equations, an extra boundary condition is imposed by augmenting the boundary condition at infinity. The governing equations are transformed into a non dimensional boundary layer equation by using non dimensional variables. The equations are solved numerically by using Keller-box method. Numerical results consist of the velocity and temperature profiles are presented graphically for assorted values of magnetic parameter, M, viscoelastic parameter, K, suction or injection parameter, f w, Prandtl number, Pr and the ratio moving parameter, X . It is found that, as the values of all parameters increased, the velocity profiles are also increased but opposite situation occurred in temperature profiles
Nuratikah Hani Abd. Rani
2017-06-20T01:25:30Z
2017-06-20T01:27:46Z
http://eprints.utm.my/id/eprint/id/eprint/33176
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33176
2017-06-20T01:25:30Z
The ford fulkerson algorithm on a case study of the dissertation scheduling problem
Scheduling problem are often hard and time consuming to solve. It is considered as one of the most difficult problem. Therefore, the development of a network model for timetabling problem is necessary to solve the problem by determining the maximum flow in the network. The purpose of this study is to develop a schedule of students versus examiner for proposal presentation exercise at Mathematical Sciences Department, Faculty of Science, UTM. In this research one of the network flow algorithm called Ford Fulkerson algorithm is applied in order to find the maximum flow of the network. Given a set of constraint consisting of a set of programs, a set of students, a set of lecturers, a set of days and periods and a set of classrooms, the problem is to assign programs to students, students to lecturer, lecturer to days and period, and lecturer to classroom subject to a set of hard and soft constraints. The computer software, MATLAB version 7.11.0 will be used to generate the Ford Fulkerson Algorithm. This is because it manages to successfully satisfy most of the constraints and optimizes the utilization of classrooms effectively and efficiently
Raja Nadiah Raja Mohd. Nazir
2017-06-19T03:44:28Z
2017-06-19T03:44:28Z
http://eprints.utm.my/id/eprint/id/eprint/62879
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/62879
2017-06-19T03:44:28Z
The effect of g-jitter on double diffusion by mixed convection past an inclined stretching sheet
In this paper, the effect of g-jitter on double diffusion by mixed convection past an inclined stretching sheet is studied. The velocity, concentration and temperature of the sheet are assumed to vary linearly with x, where x is the distance along the sheet. The resulting non-similar boundary layer equations are solved numerically using an implicit finite-difference scheme. Numerical results on the flow and heat and mass transfer characteristics are presented graphically for different values of amplitude, buoyancy ratio parameter and inclination angle. Results show that rate of heat and mass transfers increase but reduced skin friction decreases as the angle of inclination increases. It is noted that as buoyancy ratio parameter increases, rate of heat and mass transfer as well as reduced skin friction are decreases.
Noraihan Afiqah Rawi
Abdul Rahman Mohd. Kasim
Anati Ali
Mukheta Isa
Sharidan Shafie
2017-06-18T08:39:24Z
2017-06-18T08:39:24Z
http://eprints.utm.my/id/eprint/id/eprint/67164
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/67164
2017-06-18T08:39:24Z
Watson-Crick Petri net languages: the effect of labeling strategies
A Watson-Crick automaton is an automaton that works on tapes which are double stranded sequences of symbols related by Watson-Crick complementarity that are similar to the DNA molecules. However, this automaton cannot exploit the other fundamental features of DNA molecules such as the massive parallelism. Watson-Crick automata can be related to a model known as the Petri net. Petri net is a model based on the concepts of asynchronous and concurrent operation by the parts of a system and the realization by the parts can be represented by a graph or a net. From the relation between Watson-Crick automata and Petri net, a new model namely Watson-Crick Petri net has been developed. The language generated by Watson-Crick Petri net is a set of labeled sequences corresponding to the occurrence sequences of the model. In this research, some properties of languages generated by Watson-Crick Petri net are investigated.
Wan Heng Fong
Nurhidaya Mohamad Jan
Nor Haniza Sarmin
Sherzod Turaev
2017-06-18T07:16:30Z
2017-06-18T07:16:30Z
http://eprints.utm.my/id/eprint/id/eprint/67170
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/67170
2017-06-18T07:16:30Z
Watson-Crick Petri net languages with finite sets of final markings
A Watson-Crick Petri net is a new formal model that enhances a Petri net with the Watson-Crick complementary feature adapted from DNA molecules. The transitions of a Watson-Crick Petri net are labeled with pairs of symbols, and a firing sequence of transitions of the Watson-Crick Petri net is considered as successful if and only if it produces complete double stranded sequences of symmetrically related symbols according to some mode of execution termination of the firing of transitions. As an execution termination mode, we can consider the set of all reachable markings and a finite set of final markings. In this research, we investigate the fundamental properties of Watson-Crick Petri net languages with finite sets of final markings.
Nurhidaya Mohamad Jan
Wan Heng Fong
Nor Haniza Sarmin
Sherzod Turaev
2017-06-18T07:08:54Z
2017-06-18T07:08:54Z
http://eprints.utm.my/id/eprint/id/eprint/62855
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/62855
2017-06-18T07:08:54Z
The concepts of persistent and permanent in non semi-simple DNA splicing system
The investigation on the behavior of deoxyribonucleic acid (DNA) splicing languages has been of interest of many biologists and mathematicians. Yusof-Goode (Y-G) splicing system has been introduced for the purpose of showing the transparent biological process of DNA splicing systems. In this paper, the approach of Y-G splicing system is applied in presenting the persistency and permanent characteristics of non semi-simple DNA splicing system of Type I and Type II.
Yuhani Yusof
Nor Haniza Sarmin
Wan Heng Fong
2017-06-18T05:59:31Z
2017-06-18T05:59:31Z
http://eprints.utm.my/id/eprint/id/eprint/62840
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/62840
2017-06-18T05:59:31Z
The analysis of crystallographic symmetry types in finite groups
Undeniably, it is human nature to prefer objects which are considered beautiful. Most consider beautiful as perfection, hence they try to create objects which are perfectly balance in shape and patterns. This creates a whole different kind of art, the kind that requires an object to be symmetrical. This leads to the study of symmetrical objects and pattern. Even mathematicians and ethnomathematicians are very interested with the essence of symmetry. One of these studies were conducted on the Malay traditional triaxial weaving culture. The patterns derived from this technique are symmetrical and this allows for further research. In this paper, the 17 symmetry types in a plane, known as the wallpaper groups, are studied and discussed. The wallpaper groups will then be applied to the triaxial patterns of food cover in Malaysia.
Atikah Mohd. Sani
Nor Haniza Sarmin
Nooraishikin Adam
Siti Norziahidayu Amzee Zamri
2017-06-18T05:53:45Z
2017-06-18T05:53:45Z
http://eprints.utm.my/id/eprint/id/eprint/62679
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/62679
2017-06-18T05:53:45Z
Task rescheduling model for resource disruption problem in unrelated parallel processor system
In this paper, we concentrate on the scheduling problem with interruption occurs in the parallel processor system. The situation happens when the availability of the unrelated parallel processors in the time slot decreases in certain time periods and its define as resource disruption. Our objective is to consider a recovery scheduling option for this issue to overcome the possibilities of having infeasibility of the original scheduling plan. Our approach for the recovery is task rescheduling which is to assign the tasks in the initial schedule plan to reflect the new restrictions. A recovery mixed integer linear programming model is proposed to solve the disruption problem. We also conduct a computational experiment using CPLEX 12.1 solver in AIMMS 3.10 software to analyze the performance of the model.
Syarifah Zyurina Nordin
Lou Caccetta
2017-06-15T02:50:45Z
2017-06-15T02:50:45Z
http://eprints.utm.my/id/eprint/id/eprint/67125
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/67125
2017-06-15T02:50:45Z
Undoped diamond-like carbon thin films grown by direct current-plasma enhanced chemical vapour deposition: structural and electrical properties
Undoped diamond - like carbon thin films have been grown by DC - PECVD system. The synthesis of the DLC films was carried out in the presence of gas of (CH4 + H2 + Ar) in a custom - made reactor. The substrate temperature was initiated from the range of 300 °C to 600 °C under an optimum pressurized medium. The AFM image reveals that the optimization of DLC films growth at the substrate temperature 400 °C has a significant surface roughness and average grain size which is compatible to the result of film thickness measurement. The sample J400 shows an excellent nonlinear rectifying diode-like characteristic across the small potential difference.
Jackie Chen Keng Yik
Karim Deraman
Wai Kit Ong
Wan Nurulhuda Wan Shamsuri
Rosli Hussin
2017-06-15T02:41:34Z
2017-06-15T02:41:34Z
http://eprints.utm.my/id/eprint/id/eprint/63693
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/63693
2017-06-15T02:41:34Z
Timeslot mechanism in neighborhood discovery for wireless sensor networks
Neighborhood discovery (ND) in a wireless sensor network is a process of identifying the sensors that a given node can communicate directly. In ND task, each node is assigned its own N timeslots, with equal slot intervals. In each slot, each node chooses either to transmit or listen, with probabilities p and 1-p respectively. Our objectives are to analyze the optimal value of p, and model the formulation of N by mapping the problem to the occupancy problem, i.e one of the popular problem in probability theory. A number of simulations are performed and the results are compared to the theoretical formulation.
Shazirawati Mohd. Puzi
Shaharuddin Salleh
Stephan Olariu
2017-06-15T02:34:29Z
2017-06-15T02:34:29Z
http://eprints.utm.my/id/eprint/id/eprint/63633
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/63633
2017-06-15T02:34:29Z
Thermoluminescence properties of optical fibers doped with RE+3 (RE=Sm, Nd) ions subjected to X-ray irradiation
This paper describes the thermoluminescence properties of RE+3(RE=Nd, Sm) doped optical fiber SiO2. The samples were exposed to 6 MV X-ray irradiation at dose ranging from 0.5 to 4 Gy at hospital Sultan Ismail, Johor Bahru, Malaysia using the LINAC accelerator. After exposure and a certain delay of 12 h to get uniform control of thermal fading, the optical fiber TL yield was readout using a thermoluminescence (TL) reader. The optical fiber demonstrated a linear TL response versus of the absorbed dose. The linearity increases with the increasing dose while in the case of Sm-doped optical fiber, the response is comparatively smaller than Nd-doped optical fiber. Also, the glow curve of RE+3 ions doped optical fiber was compared with the undoped fibers. The results exhibit that the glow curve peaks are shifted to higher temperature due to rare-earth doping. The results indicate the TL response strongly depends on the doping type of materials. All these TL characteristics are proposing this commercial optical fiber very decisive TL material.
Azadeh Refaei
Wagiran Husin
Mohammad Alam Saeed
2017-06-13T07:53:51Z
2017-06-14T00:43:00Z
http://eprints.utm.my/id/eprint/id/eprint/33098
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33098
2017-06-13T07:53:51Z
Chemical constituents from the leaves of Garcinia Parvifolia
The chemical constituents of the leaves of G. parvifolia (known as kandis) have been investigated. Extraction of dried leaves was successfully done by cold extraction method using ethanol as solvent, followed by partitioning using n-hexane, chloroform and ethyl acetate. Fractionation and purification on the n-hexane crude extract by using Vacuum Liquid Chromatography (VLC) and Column Chromatography (CC) have resulted four compounds. The elucidation of the structures were carried out by spectroscopic techniques using IR, 1H, 13C, DEPT and GC-MS. Analysis by spectroscopic data showed the isolated compounds are ß- sitosterol, squalene, friedelin-3ß-ol, and mixture of friedelin and friedelin-3ß-ol. The antibacterial activity of crude extracts was carried out using disc diffusion methods with eight strains of bacteria, Enterococcus faecalis, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and Pseudomonas putida. Antibacterial screening showed that the chloroform crude extract gave a strong towards Klebsiella pneumonia, Pseudomonas aeruginosa and Pseudomonas putida with minimum inhibition concentration of 450 µg/mL
Atikah Salleh
2017-04-26T06:41:10Z
2017-04-26T06:41:10Z
http://eprints.utm.my/id/eprint/id/eprint/61796
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/61796
2017-04-26T06:41:10Z
DFT investigations of Ti, V doped ZnO based diluted magnetic semiconductors
The injection impurity element into ZnO has added new dimension to its versatile applications particularly in spintronics and optoelectronics. In this work, we are reporting effect of non magnetic Ti, and magnetic V impurities in ZnO. The substitution of impurity atoms has been done in ground state wurtzite (WZ) and meta stable zinc-blende (ZB) structure. Our investigations have revealed a small difference in WZ and ZB geometries of contaminated ZnO reflecting on the possibility of their experimental fabrication. Spin polarized electronic structures resembled nonmagnetic nature of Ti:ZnO in WZ and magnetic nature in ZB geometry. Similarly introduction of V in to ZnO induced magnetization in ZnO in both WZ and ZB geometry. For these investigations, we have adapted DFT approach using FP-L(APW+lo) method implemented in WIEN2k code.
Bakhtiar Ul haq
Rashid Ahmed
Amiruddin Shaari
Rafaqat Hussain
Mazmira Mohamad
2016-01-27T01:53:52Z
2017-09-17T05:16:36Z
http://eprints.utm.my/id/eprint/id/eprint/51018
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51018
2016-01-27T01:53:52Z
Effect of new thermal insulation to the growth of linbo3 single crystal by czochralski method
Single crystal of LiNbO 3 has been successfully grown by the Czochralski met hod in an air atmosphere with a r.f heating crystal growth sy stem namely Automatic Diameter Control Crystal Growth System (ADC-CGS). This paper reports on the effect of new thermal insulation on the growth process of LiNbO 3 single crystal. The effect of hot zone thermal ins ulation design was investigated. The conditions required to grow high quality LiNbO 3 single crystals are described. A set of crystal growth processes were conducted with the rotation rate of the seed at 15 rpm and the pulling rate at 2.0 mm/hr kept constant. All of the runs were grown along <104> orientation. To control the diameter of the crystal, we have to alt er the thermal environment inside the hot zone. In other words, during the crystal growth we have to i ncrease the control power to get smaller diameter and decrease the control power to get larg er diameter.
W. H. A. Kamaruddin
H. H. Kusuma
Z. Ibrahim
2016-01-27T01:53:52Z
2017-09-18T00:34:32Z
http://eprints.utm.my/id/eprint/id/eprint/51255
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51255
2016-01-27T01:53:52Z
Preliminary study of CDTE and CDTE:CU thin films nanostructures deposited by using DC magnetron sputtering
Growth and properties of CdTe and CdTe:Cu thin films nanostrucures deposited by using dc magnetron sputtering are reported. Scanning electron microscope (SEM) was used to observe the surface morphologies of the thin films. At growth conditions of 250 °C and 14 W, CdTe films did not yet evenly deposited. However, at growth temperature and plasma power of 325 °C and 43 W, both CdTe and CdTe:Cu(2%) have deposited on the substrates. In this condition, the morphology of the films indicate that the films have a grain-like nanostructures. Grain size diameter of about 200 nm begin to appear on top of the films. Energy Dispersive X-rays spectroscopy (EDX) was used to investigate chemical elements of the Cu doped CdTe film deposited. It was found that the film deposited consist of Cd, Te and Cu elements. XRD was used to investigate the full width at half maximum (FWHM) values of the thin films deposited. The results show that CdTe:Cu(2%) thin film has better crystallographic properties than CdTe thin film. The UV-Vis spectrometer was used to investigate the optical properties of thin films deposited. The transmittance spectra showed that transmittance of CdTe:Cu(2%) film is lower than CdTe film. It was found that the bandgap energy of CdTe and CdTe:Cu(2%) thin films of about 1.48 eV.
P. Marwoto
D. P. N. Made
Sugianto Sugianto
E. Wibowo
Z. Othaman
S. Y. Astuti
N. P. Aryani
2016-01-27T01:53:52Z
2017-09-18T01:21:40Z
http://eprints.utm.my/id/eprint/id/eprint/51325
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51325
2016-01-27T01:53:52Z
Structural study of cadmium lead borophosphate glass
Two series of cadmium and lead oxide modified borophosphate glass were fabricated using the melt quenching technique. The glass samples composition were xPbO:(50-x)CdO:10B2O3:40P2O5 and xPbO:(50-x)CdO:20B2O3:30P2O5. As different combinations of modifier oxides were added to the host system, changes in structural properties were expected to be observed and compared. For the study of structural properties, Fourier-Transform Infrared (FT-IR) spectroscopy and Raman spectroscopy were used. FT-IR and Raman spectroscopy were expected to produce structural information regarding the network forming borate and phosphate. Within the wavelength range of 400-2000 cm−1, multiple types of borate and phosphate stretching and bending groups were detected confirming the presence of borate and phosphate as glass forming host. Compositions and physical characteristics of all prepared samples were recorded to correlate with the both FT-IR and Raman spectroscopy spectra.
T. Y. Eeu
P. M. Leong
X. G. Pang
Z. Ibrahim
R. Hussin
2016-01-27T01:53:52Z
2017-09-18T01:37:30Z
http://eprints.utm.my/id/eprint/id/eprint/51352
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51352
2016-01-27T01:53:52Z
The effect of indium mole fraction on the growth behavior of inxga1-xas nanowires (NWS) grown using MOCVD
InxGa1-xAs NWs have been grown with various indium mole fractions (x) using MOCVD. The morphology of InxGa1-xAs NWs was observed using Field Emission-Scanning Electron Microscopy (FE-SEM) in order to study the growth behavior of the NWs. FE-SEM results show that the NWs growth mechanism has changed due to changing of indium mole fraction. At low indium mole fraction, the NWs grew via direct impinging mechanism which has produced NWs with relatively uniform diameter. By increasing the value of x the growth mechanism has transformed to the combination of direct impinging and diffusion of source atoms from the surface of substrate causing tapering of NWs. The degree of tapering increases with increasing value of indium mole fraction. InxGa1-xAs NW grown at x = 0.65 has the highest tapering factor, TF = 12.82, whereas NW grown at x = 0.41 has the lowest tapering factor, TF = 2.76.
Z. Othaman
E. Wibowo
S. Sakrani
2016-01-27T01:53:50Z
2017-06-29T01:20:15Z
http://eprints.utm.my/id/eprint/id/eprint/51323
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51323
2016-01-27T01:53:50Z
Structural and luminescence study of antimony-zinc borophosphate glass doped with iron
Antimony zinc borophosphate glass were prepared with the composition of 20ZnO-30B(2)O(3)-xP(2)O(5)-(50-x)Sb2O3-2Fe(2)O(3) (0 <= x <= 50 mol%) using the melt quenching method. The starting materials were mixed and preheat for 30 minutes and transfer into high temperature furnace for melting. The structure of samples were measured using Fourier-Transform Infrared (FT-IR) Spectroscopy. The spectra showed that network structure in the samples are mainly based on P=O, PO2, P-O, B-O-B and B-O units. With increasing P2O5 content, the vibration of P-O tends to shift towards lower wavenumber. Meanwhile, the luminescence was studied using Photoluminescence (PL) Spectroscopy. The samples were excited at specific wavelengths (265 - 300 nm). The emission profiles were obtained to study the energy transfer process. Luminescence of violet colour from samples were also recorded to correlate with PL results.
Wan Nurulhuda Wan Shamsuri
Rosli Hussin
2016-01-27T01:53:49Z
2017-07-27T00:57:58Z
http://eprints.utm.my/id/eprint/id/eprint/51270
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51270
2016-01-27T01:53:49Z
Ranking the multiple intelligences of people with epilepsy using analytical hierarchy process and data envelopment analysis
A person intelligence can be enhanced when he or she focuses and practices regularly. This paper aims to introduce an integrated Analytic Hierarchy Process and Data Envelopment Analysis (AHP-DEA) method for ranking the intelligence parameters of People with Epilepsy (PWE). In order to develop the ranking process, investigation of the effects of the patients' demographic aspects and the illness background on the intelligence parameters is essential. The proposed method is to rank the suggested intelligences that need to be improved which were obtained from ATIE, a psychometric test based on the Howard Gardner's Multiple Intelligence (MI). The result from this study is very important to improve the chances of PWE to be employed.
Vahideh Rezaie
Tahir Ahmad
Normah Maan
Siti Rahmah Awang
Masumeh Khanmohammadi
2016-01-27T01:53:49Z
2017-07-27T01:10:51Z
http://eprints.utm.my/id/eprint/id/eprint/51318
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51318
2016-01-27T01:53:49Z
State space modeling of a reheater system in power generation plant
Generally, the main components of a power plant are a gas turbine, a boiler and a steam turbine. Factors such as high pressure and temperatures affect the operational conditions and efficiency of large complex systems such as the power generation plants. Hence, it is desirable that the power plant be properly controlled in order to achieve optimum performance. Thus, a state space model is proposed. The model is mathematically convenient structure for control design and analysis of multivariable dynamic system. In addition, this approach is based on time domain analysis and synthesis using state variables. This paper focuses on the development of a state space model for a reheater system, which is one of the subsystems in the boiler of a power plant. The structural properties of the system are also analyzed. Thus, the possibility of integrating uncertainties and applying other mathematical techniques in modeling the system can be further explored.
Vahideh Rezaie
Tahir Ahmad
Normah Maan
Siti Rahmah Awang
Masumeh Khanmohammadi
2016-01-27T01:53:48Z
2017-07-24T03:40:06Z
http://eprints.utm.my/id/eprint/id/eprint/51371
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51371
2016-01-27T01:53:48Z
The thermoluminescence response of undoped silica pcf for dosimetry application
This work concerns the suitability of the undoped silica photonic crystal fibre (PCF) as ionizing radiation dosimeters. The dosimetric capabilities of PCF optical fibres in terms of thermoluminescence (TL) and dose response have been investigated and compared with the single mode fibre (SMF) subjected to 6 MeV electron irradiations. The PCF shows dose response linearity curves in a dose range familiar to conventional radiation therapy covering doses from 1 to 4Gy.
Mostafa Ghomeishi
Ghafour Amouzad Mahdiraji
Faisal Rafiq Mahamd Adikan
Suhairul Hashim
2016-01-27T01:53:47Z
2017-07-18T06:42:41Z
http://eprints.utm.my/id/eprint/id/eprint/50996
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50996
2016-01-27T01:53:47Z
Dynamic light scattering fluctuation analysis for structural phase characterization in disordered dusty plasma
Dusty plasma provides an excellent setup for studying strongly coupled Coulomb systems such as plasma crystals and plasma liquid. Based on coupling strength measured by the ratio of Coulomb electrostatic energy and thermal kinetic energy, dusty plasma can be tuned to form soft-condensed matter under moderate laboratory conditions. A standard approach to investigate uniformly ordered structures in dusty plasma is to use the inter-particle position dependent pair-correlation function, g(r). However, for non-uniform ordering of dust particles, mainly due to inhomogeneity in size and charge of the dust, the pair-correlation function is often highly noisy and difficulty to interpret, even though one could visually observe local spatial ordering in the dust particle configuration. In this study, we introduce fluctuation analysis technique based on fractal and wavelet approaches for extracting useful parameter, which, in turn can be used to characterize the structural phases in disordered dusty plasma. The Hurst exponents are determined for temporal light scattering intensity fluctuation at different neutral Argon gas pressures. It is shown that fractal exponent or Hurst parameter Hparameter can be used to describe structural complexity observed in disordered dusty plasma with inhomogeneous particle properties.
Siti Sarah Safaai
W.X. Chew
S.V. Muniandy
S. L. Yap
C. S. Wong
2016-01-27T01:53:43Z
2017-09-17T05:10:56Z
http://eprints.utm.my/id/eprint/id/eprint/51008
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51008
2016-01-27T01:53:43Z
Effect of calcinations on characterizations of fabricated nano manganese ferrite
A citric acid anionic surfactant has been applied for nano manganese ferrite (MnFeO3) fabrication using sol gel method. The calcinations have been varied for 300, 600 and 800oC. The UVDR (UV-Vis Diffused Reflectance) analysis shows a high absorptive band gap after 400 nm for the 600oC calcinated MnFeO3. The DTA (Differential Thermal Analysis) profiles exhibit remarkably trapped volatile matters (H2O, CO2, and NO2) in the fabricated MnFeO3 under sol gel heat treatment at 100oC and the peaks disappeared as the calcination increased to 600oC. As the temperature elevated from 100 to 300oC, the absorption peaks of volatile components are disappeared as demonstrated clearly by the FTIR (Fourier Transform Infrared) spectra of the fabricated material, which 3393 cm-1 corresponded to OH group, 1624 cm-1 to CO group, and 1384 cm-1 to NO group. The XRD (X-Ray Diffraction) spectra show clearly the alteration process from amorphous to crystalline structure as the calcinations increased from 300 to 600oC. In addition, the TEM (Transmission Electron Microscope) analysis exhibits parts of the fabricated MnFeO3 found in cubic nano size of 15-40 nm under interested calcinations and the result is in agreement with that obtained by XRD investigation.
R. Sundari
T. I. Hua
M. Rusli Yosfiah
2016-01-27T01:53:43Z
2017-09-17T07:58:07Z
http://eprints.utm.my/id/eprint/id/eprint/51148
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51148
2016-01-27T01:53:43Z
Luminescence properties of rare earth and transition metal ions doped potassium lead borophosphate glass
A series of potassium lead borophosphate glass doped with rare earth and transition metal ions were fabricated using melt-quenching method without annealing process. With the composition of glass 0.15K2O–0.15PbO–0.35B2O3–0.5P2O5 as host doped with 0.01 mole % of neodymium oxide, iron oxide, yttrium oxide, and titanium oxide as activator and different composition were used to investigate the luminescence effect by using Photoluminescence Spectroscopy and UV-Vis (Ultraviolet-Visible) spectrophotometer. By exciting the samples at different wavelength (200-900 nm), the excitation and emission profile were obtained and analyzed to study the energy transfer process. By referring to the spectra obtained, selected samples were also codoped among each other to obtain desired luminescence properties. UV-Visible spectroscopy results revealed the absorption and transmission wavelength of samples for targeted application as a selected band filter. Physical properties such as chemical stability and color of the samples were also recorded to correlate with PL and UV-Vis result. Certain rare earth activated samples displayed slight coloring under the visible wavelength especially Nd2+ ions doped samples displayed slight purplish.
P. M. Leong
T. Y. Eeu
T. Q. Leow
R. Hussin
Z. Ibrahim
2016-01-27T01:53:43Z
2017-09-17T07:59:25Z
http://eprints.utm.my/id/eprint/id/eprint/51149
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51149
2016-01-27T01:53:43Z
Luminescence studies on lithium- strontium borophosphate glasses doped with CR, NI and ZN ions
Luminescence material is a solid which converts certain types of energy into electromagnetic radiation over and above thermal radiation. Due to the limited studies on luminescence properties of the transition metal ion doped glass, this present study aiming to understand further the effect of doping different transition metal ions to the luminescence properties. This paper report on the luminescence properties of 20Li2O-20SrO-30B2O3-30P2O5 glasses doped from the photoluminescence spectroscopy. The luminescence spectra of 20Li2O-20SrO-30B2O3-30P2O5-x with x = 1 mol % of different transition metal ions (Cr, Ni, and Zn) which had been prepared by melt quenching technique. The luminescence properties were analyzed using photoluminescence spectroscopy. Based on the emission spectra obtained from 20Li2O-20SrO-30B2O3-30P2O5-Cr, it consists of two emission bands at around 348 nm and 369 nm. While for the luminescence spectra of 20Li2O-20SrO-30B2O3-30P2O5-Ni, it exhibits only one emission band which is at around 363 nm. Lastly, for the luminescence spectra of 20Li2O-20SrO-30B2O3-30P2O5-Zn, it exhibits two emission bands at around 379 nm and 434 nm.
W. P. Sum
W. M. Hua
R. Hussin
Z. Ibrahim
2016-01-27T01:53:43Z
2017-09-18T01:20:39Z
http://eprints.utm.my/id/eprint/id/eprint/51324
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51324
2016-01-27T01:53:43Z
Structural and luminescence study on titanium doped lead manganese borophosphate glass
A series of lead manganese borophophate glass samples were prepared and studied to determine the structural and luminescence properties using Fourier Transform Infrared Spectroscopy (FT-IR) and Photoluminescence Spectrophotometer. The glass samples with composition of 20PbO-xMnO2-30B2O3-(50-x)P2O5-2TiO2 where 0 ≤ x ≤ 20 were prepared using melt-quenching technique in air atmosphere. The samples containing different MnO2 and P2O5 content were both subjected to FT-IR testing to show the contrary effects of the network modifier. Infrared absorption spectrum shows vibrational bands of BO4 and PO3 structure within the borophosphate network structure, with the dominant BO units increasing with lower P2O5 mol%. All glassy samples exhibit photoluminescence emission in the visible range. Manganese contained samples shows violet emissions while those without show violet-blue emission when excited by UV.
T. Q. Leow
T. Y. Eeu
P. M. Leong
X. G. Pang
R. Hussin
2016-01-27T01:53:43Z
2017-09-18T01:22:39Z
http://eprints.utm.my/id/eprint/id/eprint/51326
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51326
2016-01-27T01:53:43Z
Structural study on lithium-barium borophosphate glasses using infrared and raman spectroscopy
This paper reported on the structural properties of Lithium-Barium borophosphate glasses. The glasses were prepared through melt quenching technique and studied in the compositional series which was 25Li2O:25BaO:(x)B2O3:(50-x)P2O5 where 0x50 mol% .The aims of this work were to investigate the vibration mode about the local order around phosphorus tetrahedral structures and the boron coordination changed from trigonal to tetrahedral structures. Their basic properties were determined and their structure was studied by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. Both spectroscopy analysis of the sample revealed vibration mode related to the characteristic phosphate bonds and borate bonds especially P-O-P, O-P-O ,P-O-B, BO3 and BO4. Structural studies were devoted to the investigation of changes in boron coordination in the dependence on changes in B2O3 or P2O5 ratio in the borophosphate glasses. The decrease in the strength of the vibrations of the non-bridging PO2 groups seems to indicate a progressive increase in the connectivity of the glass with increasing B2O3 content. It was likely that this connectivity was due to the formation of P-O-B links at 890 cm-1, which replaced the vibration mode P-O-P. The increasing of B2O3 content and decreasing the P2O5 content causes the boron coordination changes from trigonal to tetrahedral and the basic units change from BO3 to BO4. Overall, the high frequency bands corresponding to stretching vibration become broader, less distinct and overlap each other with an increasing B2O3 content and decreasing P2O5 content.
W. M. Hua
W. P. Sum
R. Hussin
Z. Ibrahim
2016-01-27T01:53:41Z
2017-09-17T08:46:58Z
http://eprints.utm.my/id/eprint/id/eprint/51206
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51206
2016-01-27T01:53:41Z
Numerical simulation of hypoxic cell regulation in avascular tumor growth
Avascular tumor is an early stage of tumor which does not have the blood vessels themselves and depends entirely on the cells around them to get the supply of nutrients such as oxygen and glucose. Hypoxia is a condition in which living cells are deprived of oxygen needed to maintain metabolism and growth. In avascular tumor, the hypoxic environment inhibits the cells proliferation and distinguishes the cellular dynamics into proliferative, quiescent and necrotic cells. In this paper, we present a numerical simulation of mathematical model describing these cellular dynamics using Matlab software with R2009a version. The model formulated in the form of one-dimensional parabolic partial differential equations depending on time and space. The discretization is based on forward differential respect to time and central differential respect to space of finite difference approximation. The results of simulation show that the distribution of proliferating, quiescent and necrotic cells within a tumor spheroid with respect to time and the cells regulation under different rates of nutrients consumptions in one-dimensional computational domain. In conclusion, in the hypoxic environment, the proliferative and quiescent cells grow slowly dependent on some parameter changes and the necrotic cells emerged at the tumor core.
N. Mohd. Said
A. Ibrahim
N. Alias
2016-01-27T01:53:40Z
2017-09-18T00:13:26Z
http://eprints.utm.my/id/eprint/id/eprint/51213
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51213
2016-01-27T01:53:40Z
On NTH commutativity degree of some 3-engel groups
This paper focuses on some 3-Engel groups. Suppose x and y are elements of a group G. The commutativity degree of a group is the probability that two elements in the group commute and is denoted by P(G). Meanwhile, the nth commutativity degree of a group G is the probability that for any pairs of x and y in G, xn and y commute. In this paper, the nth commutativity degree of some 3-Engel groups is determined.
Z. Yahya
N. M. Mohd. Ali
N. H. Sarmin
M. S. Sabani
M. Zakaria
2016-01-27T01:53:40Z
2017-09-18T00:45:30Z
http://eprints.utm.my/id/eprint/id/eprint/51277
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51277
2016-01-27T01:53:40Z
Relative commutativity degree of some dihedral groups
The commutativity degree of a finite group G was introduced by Erdos and Turan for symmetric groups, finite groups and finite rings in 1968. The commutativity degree, P(G), is defined as the probability that a random pair of elements in a group commute. The relative commutativity degree of a group G is defined as the probability for an element of subgroup, H and an element of G to commute with one another and denoted by P(H,G). In this research the relative commutativity degree of some dihedral groups are determined.
M. Abdul Hamid
N. M. Mohd. Ali
N. H. Sarmin
F. N. Abd. Manaf
2016-01-27T01:53:40Z
2017-09-18T01:41:04Z
http://eprints.utm.my/id/eprint/id/eprint/51358
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51358
2016-01-27T01:53:40Z
The exterior degree of symmetric group of order six
The idea to compute the exterior degree of a finite group G started in 2011. The exterior degree of a group is the probability that two randomly selected elements x and y in the group such that x ∧ y = 1 and denoted as P̂(G). However, in order to examine the exterior degree of a finite group, the nonabelian tensor square and some homological functors of the group must first be explored and determined. The homological functors that are used in determining the exterior degree of G are ∇(G) and the exterior square of G. In this research, the nonabelian tensor square, ∇(G) and the exterior square of symmetric group of order six are determined. Then, the exterior degree of symmetric group of order six is computed.
A. A. B. Nawi
N. M. Mohd. Ali
N. H. Sarmin
2016-01-27T01:53:40Z
2017-09-18T01:43:37Z
http://eprints.utm.my/id/eprint/id/eprint/51363
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51363
2016-01-27T01:53:40Z
The NTH commutativity degree of some 2-engel groups
Suppose x and y are elements of a group G. The commutativity degree of a group G is defined as the total number of pair (x, y) for which x and y commute divided by the total number of pair (x, y) which is possible. Moreover, the nth commutativity degree of a group G is the total number of pair (x, y) for which xn and y commute divided by the total number of (x, y) which is possible. In this research, all 2-Engel groups of order at most 25 are first determined. Then, the nth commutativity degree of those groups are computed.
Z. Yahya
N. M. Mohd. Ali
N. H. Sarmin
N. A. Johari
2016-01-27T01:53:40Z
2017-09-18T01:46:28Z
http://eprints.utm.my/id/eprint/id/eprint/51366
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51366
2016-01-27T01:53:40Z
The probability of nth degree for some nonabelian metabelian groups
A group G is metabelian if and only if there exists an abelian normal subgroup, A such that the factor group, G/A is abelian. For any group G, the commutativity degree of G is the probability that two randomly selected elements in the group commute and denoted as P(G). Furthermore, the probability of nth degree of a group G, Pn(G) is defined as the probability that the nth power of a random element commutes with another random element of the same group. It is also known as the nth commutativity degree of a group. In this paper, P(G) and Pn(G) for some nonabelian metabelian groups are determined.
Z. Abd. Halim
N. M. Mohd. Ali
2016-01-27T01:53:40Z
2017-09-18T01:48:32Z
http://eprints.utm.my/id/eprint/id/eprint/51369
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51369
2016-01-27T01:53:40Z
The schur multiplier and nonabelian tensor square of some groups of p-power order
Let G be a group. The Schur multiplier of the group, M(G), is the second homology group of G with integer coefficients. In 1987, the nonabelian tensor square, G ⊗ G, of a group G was introduced. Nonabelian tensor square is one of the homological invariant which originated in homotopy theory. In this research, we determine the Schur multiplier and nonabelian tensor square of groups of order p3 and p4, where p is an odd prime.
R. Zainal
N. M. Mohd. Ali
N. H. Sarmin
S. Rashid
2016-01-27T01:53:39Z
2017-09-12T07:16:45Z
http://eprints.utm.my/id/eprint/id/eprint/51370
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51370
2016-01-27T01:53:39Z
The schur multipliers of certain bieberbach groups with abelian point groups
The Schur multiplier of a group G is the kernel of a homomorphism κ′ from the exterior square of the group, G ∧ G to its commutator subgroup, G′ defined by κ′(g ∧ h) = [g,h] for g,h ∈ G. In this research, the Schur multipliers are computed for certain Bieberbach groups with abelian point groups. A Bieberbach group is a torsion free crystallographic group. It is an extension of a free abelian group L of finite rank by a finite group P. Here, L is known as the lattice group while P is the point group of the Bieberbach group.
Hazzirah Izzati Mat Hassim
Nor Haniza Sarmin
Nor Muhainiah Mohd. Ali
Rohaidah Masri
Nor'ashiqin Mohd. Idrus
2016-01-27T01:53:35Z
2017-08-20T04:21:16Z
http://eprints.utm.my/id/eprint/id/eprint/51372
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51372
2016-01-27T01:53:35Z
The three statistical control charts using ranked set sampling
This article investigated the performance of the three common statistical control charts, the Shewhart x̅ chart, cumulative sum (CUSUM) chart, and exponentially weighted moving average (EWMA) chart for location using ranked set sampling (RSS) instead of the traditional simple random sampling (SRS). Considering a normal population, a Monte Carlo simulation is carried out for several shift values for each of the control chart. The average run length (ARL) showed that the control charts based on RSS data are superior to their corresponding SRS counterparts with no significant difference between CUSUM and EWMA charts. There is an interesting increase in the sensitivity of RSS based Shewhart x̅ chart relative to other charts.
M. R. Abujiya
M. H. Lee
2016-01-27T01:53:31Z
2017-09-17T07:25:04Z
http://eprints.utm.my/id/eprint/id/eprint/51119
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51119
2016-01-27T01:53:31Z
Influence of europium ion on structural, mechanical and luminescence behavior of tellurite nanoglass
Understanding the mechanism of enhanced luminescence of rare earth doped glasses in the presence of nanocrystallites and growth kineics is fundamentally important for optical devices. Tellurite nanoglasses of composition (80-x) TeO2 − 5 Na2O − 15 MgO − (x) Eu2O3, over the concentration region of 0 to 2.5 mol% are prepared using conventional melt-quenching technique. The nanocrystalline particles are obtained by heating the as-cast glass at temperature 15−20°C above the glass crystallization temperature (Tc). The sizes of nanocrystallites are estimated from the X-Ray Diffraction (XRD) pattern using the Scherrer equation having average diameter ~68.7 nm. SEM studies revealed the nanocrystal glass morphology associated with the existence of crystalline phase. The glass density is determined by Precisa Densitometer and the hardness by the Vickers micro-hardness method. The density of tellurite nano-glass is found to be in the range of 5.2413 to 5.4933 g cm−3 while the Vickers microhardness varies from 2.77 to 2.93 GPa depending on the dopant concentration. The photoluminescence (PL) spectra exhibits five peaks around 568 nm, 600 nm, 628 nm, 664 nm and 712 nm assigned to 5D0 → 7F0, 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4 transitions respectively. Interestingly, the FWHM and the inverse quality factor of the heat-treated glass are found to decrease with increasing concentration of Eu3+ dopants. Our observation may contribute towards the development of solid state lasers.
E. S. Sazali
M. R. Sahar
S. K. Ghoshal
2016-01-27T01:53:29Z
2017-09-14T08:21:21Z
http://eprints.utm.my/id/eprint/id/eprint/50922
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50922
2016-01-27T01:53:29Z
Autocorrelated multivariate process control: a geometric brownian motion approach
In real life we always come across autocorrelated multivariate process where the present process is related to the previous process. This type of process can be modeled using the traditional multivariate time series models and then the process control can be conducted based on the residual which becomes univariate in nature. However, in this paper, we show that many time series are governed by a geometric Brownian motion (GBM) process. In this case, instead of time series modeling, we only need an appropriate transformation to come up with the condition required in the traditional multivariate process control. Therefore, under GBM process, traditional multivariate process control can be used on the transformed time series data. A real industrial example will be given to illustrate the advantage of the proposed method.
R. Sagadavan
M. A. Djauhari
2016-01-27T01:53:29Z
2017-09-17T08:13:34Z
http://eprints.utm.my/id/eprint/id/eprint/51178
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51178
2016-01-27T01:53:29Z
Monitoring autocorrelated process: a geometric brownian motion process approach
Autocorrelated process control is common in today's modern industrial process control practice. The current practice of autocorrelated process control is to eliminate the autocorrelation by using an appropriate model such as Box-Jenkins models or other models and then to conduct process control operation based on the residuals. In this paper we show that many time series are governed by a geometric Brownian motion (GBM) process. Therefore, in this case, by using the properties of a GBM process, we only need an appropriate transformation and model the transformed data to come up with the condition needs in traditional process control. An industrial example of cocoa powder production process in a Malaysian company will be presented and discussed to illustrate the advantages of the GBM approach.
L. S. Li
M. A. Djauhari
2016-01-27T01:53:29Z
2017-09-17T08:15:43Z
http://eprints.utm.my/id/eprint/id/eprint/51186
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51186
2016-01-27T01:53:29Z
Multidimensional stock network analysis: an escoufier's RV coefficient approach
The current practice of stocks network analysis is based on the assumption that the time series of closed stock price could represent the behaviour of the each stock. This assumption leads to consider minimal spanning tree (MST) and sub-dominant ultrametric (SDU) as an indispensible tool to filter the economic information contained in the network. Recently, there is an attempt where researchers represent stock not only as a univariate time series of closed price but as a bivariate time series of closed price and volume. In this case, they developed the so-called multidimensional MST to filter the important economic information. However, in this paper, we show that their approach is only applicable for that bivariate time series only. This leads us to introduce a new methodology to construct MST where each stock is represented by a multivariate time series. An example of Malaysian stock exchange will be presented and discussed to illustrate the advantages of the method.
G. S. Lee
M. A. Djauhari
2016-01-27T01:53:29Z
2017-09-18T01:50:36Z
http://eprints.utm.my/id/eprint/id/eprint/51374
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51374
2016-01-27T01:53:29Z
Time series behaviour of the number of Air Asia passengers: a distributional approach
The common practice to time series analysis is by fitting a model and then further analysis is conducted on the residuals. However, if we know the distributional behavior of time series, the analyses in model identification, parameter estimation, and model checking are more straightforward. In this paper, we show that the number of Air Asia passengers can be represented as a geometric Brownian motion process. Therefore, instead of using the standard approach in model fitting, we use an appropriate transformation to come up with a stationary, normally distributed and even independent time series. An example in forecasting the number of Air Asia passengers will be given to illustrate the advantages of the method.
N. M. Asrah
M. A. Djauhari
2016-01-27T01:53:28Z
2017-09-14T08:02:30Z
http://eprints.utm.my/id/eprint/id/eprint/50909
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50909
2016-01-27T01:53:28Z
Application of frumkin isotherm for carbon steel corrosion in soil media
This study investigated carbon steel corrosion in three types of soil media (laterite, yellow soil and kaolin). The Frumkin isotherm was used to study the mechanism of the corrosion process. A good linear correlation (y = 3.4x + 3.3) in terms of soil concentration vs. surface coverage was obtained with the value of R2 = 0.996 for carbon steel corrosion in laterite solution at 30oC. A standard weight loss method was used to determine the degree of surface coverage. Investigation on corrosion rate was also carried out on the basis of immersion time and temperature effects. The results showed that yellow soil solution yielded the highest corrosion rate on carbon steel coupon for 5 consecutive days and at various temperatures (30 – 90oC). The thermodynamic properties in terms of heat of reaction and entropy were also investigated in this corrosion study. The results showed that carbon steel coupon was least corroded in the environment of kaolin solution as indicated by its highest endothermic value and lowest entropy. The study showed that the findings are consistent in relation to thermodynamic properties. This work is beneficial for the corrosion study of carbon steel in soil media corresponding to lifetime of buried pipelines and cost safety.
A. W. M. Sa'adan
M. Aziz
R. Sundari
2016-01-27T01:53:28Z
2017-09-17T06:33:29Z
http://eprints.utm.my/id/eprint/id/eprint/51070
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51070
2016-01-27T01:53:28Z
Fesem-edx and CV characteristics of dopant (mn, co, ni) magnesium ferrites
Doping magnesium ferrites (MgFe2 O4) with Mn, Co and Ni, which were synthesized by sol gel method using citric acid and polyvinyl alcohol (P VA) and calcined at 500oC, showed interesting electrochemical featur es based on their cyclic voltammetric (CV) characteristics using 5 µL ferrite – poly vinylidene fluoride in ethano l deposited on a screen printed carbon electrode (SPCE) in a mixture of 1.0 M KOH and ferricyanide solution recorded with a scan rate of 0.02 Vs -1. The Mn doped magnesium ferrite (x = 0.9) showed the most remarkable CV performance over other doped element (Co and Ni) and un-doped magnesiu m ferrites. The surface morphology of doped ferrites was studied by applying a field emissi on scanning electron microscope (FESEM) in conjunction with an energy dispersive X-ray spect roscopy (EDX) analysis. The results revealed that Mn posed the highest percentage on the surface ( ≈ 21.5 %), followed by Co (≈ 19.5%) and Ni ( ≈ 6.7%) with respect to x = 0.9 of M0.9Mg0.1Fe 2 O4 (M = Co, Mn and Ni) at 500oC calcination. The study showed the possibility of yielding semi conducting ferrites using own fabricated magnesium ferrite and its metal doping.
S. S. Jonit
M. Aziz
R. Sundari
2016-01-27T01:53:28Z
2017-09-17T06:47:27Z
http://eprints.utm.my/id/eprint/id/eprint/51080
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51080
2016-01-27T01:53:28Z
Free vibration of antisymmetric angle-ply laminated annular circular plate
Free vibration of laminated antisymmetric angle- ply annular circular plates are studied with inclusion of first order shear deformation theory using a spline function approximation by applying a point collocation method. The equations of motion of the plates are derived using first order shear deformation theory. The vibration of two- and four- layered plates are analysed, made up of two types of materials and two types of boundary conditions. A generalized eigenvalue problem is obtained and solved numerically for obtaining the required eigenfrequency parameters and associate eigenvectors are spline coefficients. The stability of the annular circular plate is analyzed with respect to the radii ratio, circumferential node number, different materials, number of laminates, ply orientations under different boundary conditions for two and four layered plates.
K. K. Viswanathan
S. Javed
Z. A. Aziz
2016-01-27T01:53:27Z
2017-09-14T06:59:29Z
http://eprints.utm.my/id/eprint/id/eprint/50873
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50873
2016-01-27T01:53:27Z
A theoretical model of all-optical switching induced by a soliton pulse in nano-waveguide ring resonator
We propose a theoretical model of 1×2 all-optical switching in a silicon nano-waveguide ring resonator induced by a soliton pulse. All-optical switches made by silicon fiber or silicon waveguide have attracted much attention, because the low-absorption wavelength windows of silicon material just match optical fiber communication. However, to achieve all-optical switching in silicon is challenging owing to its relatively weak nonlinear optical properties and require high switching power, which is much higher than the signal power. Such high power is inappropriate for effective on-chip integration. To overcome this limitation, we have used a highly confined nano-waveguide ring resonator structure with soliton pulse input to enhance the nonlinearity and this leads to enhance the effect of refractive index change on the transmission response. The refractive index is changed by controlling the free-carrier concentration through two-photon absorption (TPA) effect. The result indicates that a refractive index change as small as 6.4×10−3 can reduce the switching power to 2.38 ×10−6 W. The nano-waveguide ring resonator all-optical switching described here is achieved by using the concept of strong light confinement, and the switching power is approximately three orders of magnitude lower than the available silicon optical switches. Such controllable switch is desired for achieving high performance in nanometer-size planar structures.
I. N. M. Nawi
M. Bahadoran
J. Ali
P. Yupapin
2016-01-27T01:53:25Z
2017-09-13T08:14:23Z
http://eprints.utm.my/id/eprint/id/eprint/51342
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51342
2016-01-27T01:53:25Z
Terahertz characterization via an all-optical, ultra-thin-knife-edge technique
An all-optical, terahertz characterization based on a ultra-thin-knife-edge is demonstrated employing an ultraviolet-pulse to project the image of a blade on a ZnTe crystal, where the free carriers excited on a blade-shaped area act as a field-shield.
S. P. Ho
M. Shalaby
M. Peccianti
M. Clerici
A. Pasquazi
Y. Ozturk
J. Ali
R. Morandotti
2016-01-27T01:53:24Z
2017-06-12T05:00:22Z
http://eprints.utm.my/id/eprint/id/eprint/50923
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50923
2016-01-27T01:53:24Z
Automata representation for abelian groups
A finite automaton is one of the classic models of recognition devices, which is used to determine the type of language a string belongs to. A string is said to be recognized by a finite automaton if the automaton "reads" the string from the left to the right starting from the initial state and finishing at a final state. Another type of automata which is a counterpart of sticker systems, namely Watson-Crick automata, is finite automata which can scan the double-stranded tapes of DNA strings using the complimentary relation. The properties of groups have been extended for the recognition of finite automata over groups. In this paper, two variants of automata, modified deterministic finite automata and modified deterministic Watson-Crick automata are used in the study of Abelian groups. Moreover, the relation between finite automata diagram over Abelian groups and the Cayley table is introduced. In addition, some properties of Abelian groups are presented in terms of automata.
Wan Heng Fong
Yeesiang Gan
Nor Haniza Sarmin
Sherzod Turaev
2016-01-27T01:53:24Z
2017-09-12T07:12:44Z
http://eprints.utm.my/id/eprint/id/eprint/51151
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51151
2016-01-27T01:53:24Z
Magic star puzzle for educational mathematics
One of the interesting fields in recreational mathematics is the magic number arrangement. There are different kinds of arrays in the arrangement for a group of numbers. In particular, one of the arrays in magic number arrangement is called magic star. In fact, magic star involves combinatorics that contributes to geometrical analysis and number theory. Hence, magic star is suitable to be introduced as educational mathematics to cultivate interest in different area of mathematics. To obtain the solutions of normal magic stars of order six, the possible sets of numbers for every line in a magic star have been considered. Previously, the calculation for obtaining the solutions has been done manually which is time-consuming. Therefore, a programming code to generate all the fundamental solutions for normal magic star of order six without including the properties of rotation and reflection has been done. In this puzzle, a magic star puzzle is created by using Matlab software, which enables a user to verify the entries for the cells of magic star of order six. Moreover, it is also user-friendly as it provides interactive commands on the inputs given by the user, which enables the user to detect the incorrect inputs. In addition, user can also choose to view all the fundamental solutions as generated by the programming code.
Siang Gan Yee
Wan Heng Fong
Nor Haniza Sarmin
2016-01-27T01:53:24Z
2017-09-12T07:09:15Z
http://eprints.utm.my/id/eprint/id/eprint/51274
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51274
2016-01-27T01:53:24Z
Regular languages, regular grammars and automata in splicing systems
Splicing system is known as a mathematical model that initiates the connection between the study of DNA molecules and formal language theory. In splicing systems, languages called splicing languages refer to the set of double-stranded DNA molecules that may arise from an initial set of DNA molecules in the presence of restriction enzymes and ligase. In this paper, some splicing languages resulted from their respective splicing systems are shown. Since all splicing languages are regular, languages which result from the splicing systems can be further investigated using grammars and automata in the field of formal language theory. The splicing language can be written in the form of regular languages generated by grammar. Besides that, splicing systems can be accepted by automata. In this research, two restriction enzymes are used in splicing systems namely BfuCI and NcoI.
Nurhidaya Mohamad Jan
Wan Heng Fong
Nor Haniza Sarmin
2016-01-27T01:53:24Z
2017-09-12T07:10:39Z
http://eprints.utm.my/id/eprint/id/eprint/51312
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51312
2016-01-27T01:53:24Z
Some characteristics of probabilistic one-sided splicing systems
A theoretical model for DNA computing using the recombination behavior of DNA molecules known as asplicing system has been introduced in 1987. Splicing systems are based on the splicing operation which, informally, cuts two strings at the specific places and attaches the prefix of the first string to the suffix of the second string and the prefix of the second string to the suffix of the first string yielding the new strings. It is known that splicing systems with finite sets of axioms and splicing rules only generate regular languages. Hence, different types of restrictions for splicing systems have been considered to increase the computational power of the languages generated. Recently, probabilistic splicing systems have been introduced where the probabilities are initially associated with the axioms, and the probabilities of the generated strings are computed from the probabilities of the initial strings. In this paper, some properties of probabilistic one-sided splicing systems, which are special types of probabilistic splicing systems, are investigated. We prove that probabilistic one-sided splicing systems can also increase the computational power of the languages generated.
Mathuri Selvarajoo
Wan Heng Fong
Nor Haniza Sarmin
Sherzod Turaev
2016-01-27T01:53:22Z
2017-09-14T07:54:27Z
http://eprints.utm.my/id/eprint/id/eprint/50896
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50896
2016-01-27T01:53:22Z
Analysis of fluconazole in human urine sample by high performance liquid chromatography method
A method for determination of fluconazole, antifungal drug in human urine by using reversed-phased high performance liquid chromatography (RP-HPLC) with ultraviolet (UV) detector was developed. Optimization HPLC conditions were carried out by changing the flow rate and composition of mobile phase. The optimum separation conditions at a flow rate 0.85 mL/min with a composition of mobile phase containing methanol:water (70:30, v/v) with UV detection at a wavelength 254 nm was able to analyze fluconazole within 3 min. The excellent linearity was obtained in the range of concentration 1 to 10 µg/mL with r2 = 0.998.
The limit of detection (LOD) and limit of quantitation (LOQ) were 0.39 µg/mL and 1.28 µg/mL, respectively. Solid phase extraction (SPE) method using octadecylsilane (C18) as a sorbent was used to clean-up and pre-concentrated of the urine sample prior to HPLC analysis. The average recoveries of fluconazole in spiked urine sample was 2.4% with RSD of 3.21% (n=3).
D. Hermawan
N. A. Md. Ali
Wan Azli Wan Ibrahim
M. M. Sanagi
2016-01-27T01:53:22Z
2017-09-04T14:12:40Z
http://eprints.utm.my/id/eprint/id/eprint/51336
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51336
2016-01-27T01:53:22Z
Synthesis and characterization of InGaAS nanowires grown by MOCVD
Semiconductor nanowires have been intensively investigated in order to study their unique fundamental and application properties that develop at the nano-scale. One of main problems in the growth of III-V semiconductor nanowire is uniformity both of in dimension and composition of chemical elements. We synthesized InGaAs nanowire on GaAs (111) substrate at 400 °C – 480 °C temperatures for 30 minutes using MOCVD. The nanowires grow perpendicular to the substrate via direct impinging mechanism and they have hexagonal shape with diameter of 80-150 nm. Dimension of nanowire, length and diameter, increase with increases of growth temperature. Formations of tapering could be controlled with growth at lower temperature.
D. Gustiono
E. Wibowo
Z. Othaman
2016-01-27T01:53:20Z
2017-06-12T21:08:24Z
http://eprints.utm.my/id/eprint/id/eprint/50858
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50858
2016-01-27T01:53:20Z
A hybrid group method of data handling with discrete wavelet transform for GDP forecasting
This study is proposed the application of hybridization model using Group Method of Data Handling (GMDH) and Discrete Wavelet Transform (DWT) in time series forecasting. The objective of this paper is to examine the flexibility of the hybridization GMDH in time series forecasting by using Gross Domestic Product (GDP). A time series data set is used in this study to demonstrate the effectiveness of the forecasting model. This data are utilized to forecast through an application aimed to handle real life time series. This experiment compares the performances of a hybrid model and a single model of Wavelet-Linear Regression (WR), Artificial Neural Network (ANN), and conventional GMDH. It is shown that the proposed model can provide a promising alternative technique in GDP forecasting.
Nadira Mohamed Isa
Ani Shabri
2016-01-27T01:53:20Z
2017-08-24T07:09:00Z
http://eprints.utm.my/id/eprint/id/eprint/51175
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51175
2016-01-27T01:53:20Z
Modeling of information flows in natural gas storage facility
The paper considers the natural-gas storage valuation based on the information-based pricing framework of Brody-Hughston-Macrina (BHM). As opposed to many studies which the associated filtration is considered pre-specified, this work tries to construct the filtration in terms of the information provided to the market. The value of the storage is given by the sum of the discounted expectations of the cash flows under risk-neutral measure, conditional to the constructed filtration with the Brownian bridge noise term. In order to model the flow of information about the cash flows, we assume the existence of a fixed pricing kernel with liquid, homogenous and incomplete market without arbitrage.
Leyla Ranjbari
Arifah Bahar
Zainal Abdul Aziz
2016-01-27T01:53:18Z
2017-09-27T07:10:04Z
http://eprints.utm.my/id/eprint/id/eprint/51268
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51268
2016-01-27T01:53:18Z
Radial slits maps of unbounded multiply connected regions
This paper presents a boundary integral equation method for conformal mapping of an unbounded multiply connected region onto a radial slits region. Two linear boundary integral equations are constructed from a boundary relationship satisfied by an analytic function on an unbounded multiply connected region. These integral equations are uniquely solvable. The kernels involved in these integral equations are the adjoint generalized Neumann kernels. Two numerical examples are presented to show the effectiveness of the proposed method.
Arif A. M. Yunus
Ali Hassan Mohamed Murid
Mohamed M. S. Nasser
2016-01-27T01:53:18Z
2017-09-27T07:14:00Z
http://eprints.utm.my/id/eprint/id/eprint/51311
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/51311
2016-01-27T01:53:18Z
Solving a mixed boundary value problem via an integral equation with adjoint generalized neumann kernel in bounded multiply connected regions
In this paper, we solve the mixed boundary value problem on bounded multiply connected region by using the method of boundary integral equation. Our approach in this paper is to reformulate the mixed boundary value problem into the form of Riemann-Hilbert problem. The Riemann-Hilbert problem is then solved using a uniquely solvable Fredholm integral equation on the boundary of the region. The kernel of this integral equation is the adjoint generalized Neumann kernel. As an examination of the proposed method, some numerical examples for some different test regions are presented.
Samer A. Al-Hatemi
Ali Hassan Mohamed Murid
Mohamed M. S. Nasser
2015-12-15T01:20:20Z
2020-07-08T08:48:07Z
http://eprints.utm.my/id/eprint/id/eprint/50696
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50696
2015-12-15T01:20:20Z
Effect of rotation speed and pulling rate on physical properties of titanium-doped sapphire single crystals
Titanium-doped sapphire single crystals with 0.20 weight percentage of dopant were successfully produced by using the Automatic Diameter Control-Crystal Growth System based on the Czochralski technique. Group A crystals were produced at a constant pulling rate of 1.50 mm h-1 and a rotational speed (8-24) rpm and Group B crystal were produced at a constant rotational speed of 15 rpm and pulling rate (0.75-1.75) mm h-1. The presence of macroscopic defects such as gas bubbles and inclusions were found in the crystals produced at low rotation speed and at high pulling rate. XRD spectra of the crystals identified synthetic corundum as the main phase of the crystals and Al2TiO5 as the second phase. EDAX analysis showed the presence of Al, O and Ti element. Temperature, control power and growth rate were investigated for their correlation on the growth process and crystal diameter profile. When the rotation speed was increased, Group A crystals showed an increase in density from 3.963 g cm-3 to 3.999 g cm-3. For group B crystals, the density decreased from 3.988 g cm-3 to 3.955 g cm-3 with increasing pulling rate. The porosity of the Group A crystals was found to decrease from 0.27% to 0.08% with increasing rotation speed. Group B crystals showed an increase in porosity from 0.09% to 0.44% with increasing pulling rate. From Vickers hardness test, the hardness of Group A crystals increased from 855 HV to 1698 HV with an increase in rotational speed. A decreased in hardness from 1439 HV to 845 HV was observed with increasing pulling rate for Group B crystals. The Young’s Modulus of Group A crystals increased from 1542 MPa to 2069 MPa with increasing rotation speed. However, when the pulling rate was increased for the Group B crystals, the Young’s Modulus was found to decrease from 2002 MPa to 1311 MPa.
Mohammad Nabil Jainal
2015-12-15T01:11:19Z
2020-07-08T03:52:19Z
http://eprints.utm.my/id/eprint/id/eprint/50678
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50678
2015-12-15T01:11:19Z
Density functional theory simulation of magnetism due to atomic vacancies in graphene using siesta
Spintronics generally refers to technology where devices utilise the spin of the electron in addition to its charge for information transmission, processing and storage.Graphene is a sheet of carbon atoms bound together with double bonds (called the sp2bonds) in a thin, one atom thick layer. It is a very special material because of the large spin relaxation length and ballistic transport characteristics that can provide a great platform for developing spin-polarized devices. The carbon atom itself does not own any magnetic moment, therefore, the researches on graphene-based spintronics mainly focus on the substantial magnetism in graphene due to the presence of defects. This study will investigate the magnetism originating from quasilocalised states inducedby defects in graphene sheet using first principle approach. The density functional theory calculations were performed using SIESTA software in the spin-unrestrictedmanner, using the diagonalization-based method for solving Kohn-Sham equations.The calculation was done in parallel modes. The generalized gradient approximation(GGA) exchange-correlation functional of Perdew, Burke and Ernzerhof (PBE) was used throughout this work. In addition, all the calculations for the models were carried out using the double-zeta plus one polarization (DZP) basis set. In this study, the magnetic moments generated due to atomic vacancies were calculated for supercellsof different sizes namely 3×3, 4×4, 5×5, and 6×6 multiples of the graphene unitcell.The results show that the values of the magnetic moment in graphene supercell sstrongly depend on the size of the supercell, the number of the vacancies as well as on the sublattice where the vacancies are located. This is generally consistent with Lieb’stheorem regarding the magnetism in materials with different sublattices. Furthermore the presence of exchange splitting in the density of states (DOS) for electrons with different spins can be considered as indication that this magnetism is of the itinerant type and this should enhance the potential of using graphene for spintronic devices.
Norshila Jarkoni
2015-12-02T02:10:40Z
2018-11-30T06:44:12Z
http://eprints.utm.my/id/eprint/id/eprint/49181
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49181
2015-12-02T02:10:40Z
Bacterial pigments and their applications
Natural pigments sourced from ores, insects, plants and animals were the colorants used since prehistoric period. Synthetic dyes which took the place of natural pigments in the middle of 19th century still rule the field to the maximum extent in spite of its hazardous effect to humans, animals and environment. As an alternative to synthetic pigments, bacterial pigments due to their better biodegradability and higher compatibility with the environment, offer promising avenues for various applications. The industry is now able to produce some bacterial pigments for applications in food, pharmaceuticals, cosmetics and textiles. Extraction of bacterial pigments in relatively pure and concentrated forms is the main technological challenge. Optimization of fermentation process and the medium components are reported as key strategies for economic recovery of pigments. Research work needs to be carried out to formulate the fermentation media for each bacterial pigment on large scale by using economical and easily available sources for commercial process. Recent advances in synthetic biology, metabolic engineering efforts of bacteria will greatly expand the pigments that could be produced economically in sufficient amounts for industrial application. This review summarizes the current technology status and challenges, economics, novel strategies for production of bacterial pigments and metabolic engineering of bacteria with a focus on applications of bacterial pigments in food industry, pharmaceutical industry, dyeing as well as on other applications.
Chidambaram Kulandaisamy Venil
Zainul Akmar Zakaria
Wan Azlina Ahmad
2015-12-02T02:10:39Z
2018-10-14T08:26:38Z
http://eprints.utm.my/id/eprint/id/eprint/49848
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49848
2015-12-02T02:10:39Z
Mechanical properties and morphological characterization of PLA/chitosan/epoxidized natural rubber composites
Poly (lactic acid) (PLA)/chitosan (CS) natural polymer/epoxidised natural rubber (ENR) composites were successfully prepared through a solution casting method. The morphological characteristics of fabricated composites were investigated by scanning electron microscopy (SEM) and optical microscopy. The microstructure of PLA/ENR was significantly altered with the addition of CS. SEM analysis of composites fractured surfaces revealed smooth and homogeneous texture and good dispersion of CS. However for 15 wt% CS composites, the phase segregation and poor adhesion between the polymers were observed. Fourier transform infrared spectroscopy revealed some levels of attractive interaction between CS, PLA, and ENR in the composites. The mechanical properties of composites in terms of tensile strength and tensile modulus were significantly improved with the addition of CS into the matrix while the percent elongation at break decreased. The tensile strength increased up to 5 wt% CS loading for both PLA/CS and PLA/ENR/CS and thereafter decreased while Young's modulus increased up to 10 wt%. However, when the CS content was increased to 15 wt%, the tensile strength and tensile modulus were slightly decreased. These improvements were attributed to good dispersion of CS at the optimum filler levels and attractive interaction between the composites components
Zainoha Zakaria
Md. Saiful Islam
Azman Hassan
M. K. Mohamad Haafiz
Reza Arjmandi
M. Inuwa
M. Hasan
2015-12-02T02:10:38Z
2018-10-14T08:26:46Z
http://eprints.utm.my/id/eprint/id/eprint/50007
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50007
2015-12-02T02:10:38Z
Hirota-sato formalism on some nonlinear waves equations
This article demonstrates that Hirota’s direct method or scheme for solving nonlinear waves equation is linked to Sato theory, and eventually resulted in the Sato equation. This theoretical framework or simply the Hirota–Sato formalism also reveals that the τ – function, which underlies the analytic form of soliton solutions of theses physically significant nonlinear waves equations, shall acts as the key function to express the solutions of Sato equation. From representation theory of groups, it is shown that the τ – function in the bilinear forms of Hirota scheme are closely connected to the Plucker relations in Sato theory. Thus Hirota–Sato formalism provides a deeper understanding of soliton theory from a unified viewpoint. The Kadomtsev–Petviashvili (KP), Korteweg–de Vries (KdV) and Sawada–Kotera equations are used to verify this framework
Noor Aslinda Ali
Zainal Abdul Aziz
2015-12-02T02:10:37Z
2018-10-14T08:26:47Z
http://eprints.utm.my/id/eprint/id/eprint/50009
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50009
2015-12-02T02:10:37Z
Identification of materials through SVM classification of their LIBS spectra
Laser Induced Breakdown Spectroscopy is a strong analytical method for qualitative studies and Support Vector Machines (SVM) is a powerful machine learning technique for pattern recognition and classification. In this paper we present an application of LIBS qualitative capability reinforced by SVM classification. Three different samples were ablated by an Nd:YAG laser and their spectra were recorded by Ocean Optics HR4000 spectrometer. These spectra possess signatures of the ablated materials. Sometimes these are visible to the naked eye while in many cases it is hard to decide about the presence of any pattern identifying a particular material. In addition variations are always found in the spectra obtained from laser induced ablation. In this situation a pattern recognition tool is very useful that sweep through the whole spectrum and record minor details. Here SVM serves the purpose. SVM classifiers were trained with distinct sets of spectra, belonging to specific materials, for classification. The results obtained from this preliminary experiment are encouraging and can lead us on positive grounds for the future work. This combination of tools can prove to be valuable for fast and automated identification and classification
Zuhaib Haider
Yusof Munajat
Raja Ibrahim Kamarulzaman
Munaf Rashid
2015-12-02T02:10:32Z
2018-10-14T08:26:46Z
http://eprints.utm.my/id/eprint/id/eprint/50006
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50006
2015-12-02T02:10:32Z
Forensic analysis of inorganic anions from post-blast pyrotechnic residues
Increase bombing activities in recent years have raised much awareness amongst forensic scientists of the importance of post-blast investigation. Analysis of post blast bomb residues is useful in identification of explosives and establishing link to its origin. The use of pyrotechnic in homemade explosives has emerged as a new threat to society. In this study, pre and post-blast inorganic anions from pyrotechnic residues were analyzed using ion chromatography with conductivity detection. Inorganic anions were separated using Metrosep A SUPP 5 anion column with NaHCO3 - Na2CO3 eluent. Eight anions (fluoride, chloride, nitrite, chlorate, nitrate, phosphate, sulfate and thiocyanate) were successfully separated within 40 min. Good linearity of calibration graph and LOD ranged from 4.8 to 21.0 ppb were achieved. Chemical anionic constituents of the fireworks were found to differ from each other. However, they were found to be common in nitrate and chlorate as oxidizer. Ratio of oxidizer was also found to be much higher than other anions. Post-blast samples showed drastic reduction in oxidizer concentration
Umi Kalsom Ahmad
Yoong Liew Choon
Mohamad Afiq Mohamed Huri
Shaikh Abdul Adzis Shaikh Abdullah
2015-12-02T02:10:29Z
2018-10-14T08:37:03Z
http://eprints.utm.my/id/eprint/id/eprint/50572
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50572
2015-12-02T02:10:29Z
Global convergence of two spectral conjugate gradient methods
Two new nonlinear spectral conjugate gradient methods for solving unconstrained optimization problems are proposed. One is based on the Hestenes and Stiefel (HS) method and the spectral conjugate gradient method. The other is based on a mixed spectral HS-CD conjugate gradient method, which combines the advantages of the spectral conjugate gradient method, the HS method, and the CD method. The directions generated by the methods are descent directions for the objective function. Under mild conditions, we prove that the spectral conjugate gradient methods with an Armijo-type line search are globally convergent. Numerical results show the proposed methods are promising
Mahdi Ghanbari
Tahir Ahmad
Norma Alias
Mohammadreza Askaripour
2015-12-02T02:10:28Z
2018-10-14T08:26:45Z
http://eprints.utm.my/id/eprint/id/eprint/50004
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50004
2015-12-02T02:10:28Z
Evaluation of different EEG source localization methods using testing localization errors
The ideas underlying the quantitative localization of the sources of the EEG review within the brain along with the current and emerging approaches to the problem. The ideas mentioned consist of distributed and dipolar source models and head models ranging from the spherical to the more realistic based on the boundary and finite elements. The forward and inverse problems in electroencephalography will debate. The inverse problem has non-uniqueness property in nature. More precisely, different combinations of sources can produce similar potential fields occur on the head. In contrast, the forward problem does have a unique solution. The forward problem calculates the potential field at the scalp from known source locations, source strengths and conductivity in the head, and it can be used to solve the inverse problem. In the final part of this paper, we compare the performance of three well–known EEG source localization techniques which applied to the underdetermined (distributed) source localization of the inverse problem. These techniques consist of LORETA, WMN and MN, which comparing by testing localization error
Leila SaeidiAsl
Tahir Ahmad
2015-12-02T02:10:27Z
2018-10-23T02:04:51Z
http://eprints.utm.my/id/eprint/id/eprint/49939
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49939
2015-12-02T02:10:27Z
Analysis of photon scattering trends for material classification using artificial neural network models
In this project, we concentrate on using the Artificial Neural Network (ANN) approach to analyze the photon scattering trend given by specific materials. The aim of this project is to fully utilize the scatter components of an interrogating gamma-ray radiation beam in order to determine the types of material embedded in sand and later to determine the depth of the material. This is useful in a situation in which the operator has no knowledge of potentially hidden materials. In this paper, the materials that we used were stainless steel, wood and stone. These moderately high density materials are chosen because they have strong scattering components, and provide a good starting point to design our ANN model. Data were acquired using the Monte Carlo N-Particle Code, MCNP5. The source was a collimated pencil-beam projection of 1 MeV energy gamma rays and the beam was projected towards a slab of unknown material that was buried in sand. The scattered photons were collected using a planar surface detector located directly above the sample. In order to execute the ANN model, several feature points were extracted from the frequency domain of the collected signals. For material classification work, the best result was obtained for stone with 86.6% accurate classification while the most accurate buried distance is given by stone and wood, with a mean absolute error of 0.05
M. Iqbal Saripan
Wira Hidayat Mohd. Saad
Suhairul Hashim
Ahmad Taufek Abdul Rahman
Kevin Wells
David Andrew Bradley
2015-12-02T02:10:26Z
2018-09-27T04:07:24Z
http://eprints.utm.my/id/eprint/id/eprint/49250
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49250
2015-12-02T02:10:26Z
Activities of heterogeneous acid-base catalysts for fragrances synthesis: a review
This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of the various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves, have been reported. Generally, heterogeneous acid catalysts are more commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous acid and base catalysts, respectively.
Hartati Hartati
Mardi Santoso
Sugeng Triwahyono
Didik Prasetyoko
2015-12-02T02:10:26Z
2018-11-30T06:55:13Z
http://eprints.utm.my/id/eprint/id/eprint/49327
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49327
2015-12-02T02:10:26Z
C5–C7 linear alkane hydroisomerization over MoO3–ZrO2 and Pt/MoO3–ZrO2 catalysts
The catalytic activity of MoO3–ZrO2 and Pt/MoO3–ZrO2 has been assessed based on the C5–C7 linear alkane hydroisomerization in a microcatalytic pulse reactor at 323–623 K. The introduction of Pt altered the crystallinity and acidity of MoO3–ZrO2. The catalytic activity of Pt/MoO3–ZrO2 was inferior than that of MoO3–ZrO2, although the Pt/MoO3–ZrO2 performed higher hydrogen uptake capacity. IR and ESR studies confirmed the heating of MoO3–ZrO2 in the presence of hydrogen formed active protonic acid sites and electrons which led to change in the Mo oxidation state. Similar phenomenon was observed for Pt/MoO3–ZrO2 at ⩽323 K. Contrarily, heating of Pt/MoO3–ZrO2 in the presence of hydrogen at higher temperature did not form protonic acid sites but intensified Lewis acidic sites. It is suggested that Pt facilitates in the interaction of spiltover hydrogen atom and MoO3 to form MoO2 or Mo2O5 over ZrO2 support which may be intensified the Lewis acidic sites.
Sugeng Triwahyono
Aishah Abdul Jalil
Nurun Najwa Ruslan
Herma Dina Setiabudi
Nur Hidayatul Nazirah Kamarudin
2015-12-02T02:10:26Z
2019-01-28T04:30:34Z
http://eprints.utm.my/id/eprint/id/eprint/50353
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50353
2015-12-02T02:10:26Z
CO3O4 doped over SBA 15: excellent adsorbent materials for the removal of methyleneblue dye pollutant
Nanosized cobalt oxide particles are incorporated into SBA 15 mesoporous silica materials and are effectively used for the first time as adsorbent materials for aquatic dye pollutant removal. Cobalt is found to exist in its Co3O4 spinel structure as evident from FTIR and X-ray diffraction studies. The best weight ratio of metal loading to show excellent adsorption of methyleneblue is found to be 10 wt% Co over the support. There, Co3O4 spinel nanoparticles lie inside the pores of mesoporous silica. Further increase in the percentage of metal loading decreases the adsorption capacity which may be due to the agglomeration of nanoparticles over the silica support as evident from TEM photographs. Cobalt-doped systems of the present study, having good adsorption capacity of methyleneblue, are prepared via impregnation of cobalt nitrate over SBA 15 in aqueous medium. Here, we introduce a new SBA 15-based system for the fast removal of aquatic dye pollutants which is highly economical for industrial applications.
P. V. Suraja
Zahira Yaakob
N. N. Binitha
Sugeng Triwahyono
P. P. Silija
2015-12-02T02:10:20Z
2018-10-21T04:33:20Z
http://eprints.utm.my/id/eprint/id/eprint/49303
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49303
2015-12-02T02:10:20Z
Unsteady MHD mixed convection stagnation-point flow in a micropolar fluid on a vertical surface in a porous medium with Soret and Dufour effects
The problem of an unsteady MHD mixed convection flow with heat and mass transfer in a micropolar fluid near the forward stagnation point in a porous medium with Soret and Dufour effects has been investigated. The self-similarity transformation is used to transform the governing equations and then to solve them numerically using an implicit finite difference scheme. In this study, we consider both assisting and opposing flows. The profiles of velocity, microrotation, temperature, and concentration, as well as the skin friction, and the rate of heat and mass transfer are determined and presented graphically for physical parameters. The results show that the magnetic parameter decreases the reduced skin friction and reduced heat and mass transfer for the assisting flow while the opposite trend is observed for the case of opposing flow. It is also found that the buoyancy parameter decreases the thermal and concentration boundary layer thickness for an assisting flow and increases for an opposing one
Aurang Zaib
Abdul Rahman M. Kasim
Nurul Farahain Mohammad
Sharidan Shafie
2015-12-02T02:10:20Z
2019-01-28T04:30:32Z
http://eprints.utm.my/id/eprint/id/eprint/49990
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49990
2015-12-02T02:10:20Z
Closed-form solutions for unsteady magnetohydrodynamic flow in a porous medium with wall transpiration
This problem deals with an unsteady two-dimensional magnetohydrodynamic flow of incompressible viscous fluid over a flat plate with wall transpiration embedded in a porous medium. Exact solutions corresponding to the Stokes first and second problems are obtained using an extended separation of variable technique together with the similarity arguments. The corresponding starting solutions are presented as the sum of steady state and transient solutions. Further, it is found that for small time t the difference between the steady state and the transient solutions is significant. However, for large values of t, both of these solutions become identical. These solutions do not involve any unevaluated integral and are expressed in terms of exponential and complementary error functions. Effects of the material parameters on the velocity fields are investigated by plotting the graphs. The nature of the wall shear stress engendered due to the flow is also studied by presenting the results in graphical and tabular forms. Some well-known and fundamental solutions existing in the literature are also obtained as the limiting cases of our solutions.
Mohammed Abdulhameed
Ilyas Khan
Arshad Khan
Sharidan Shafie
2015-12-02T02:10:20Z
2019-01-28T04:30:36Z
http://eprints.utm.my/id/eprint/id/eprint/50583
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50583
2015-12-02T02:10:20Z
Chemical reaction and uniform heat generation or absorption effects on MHD stagnation-point flow of a nanofluid over a porous sheet
The objective of this work is to analyze the chemical reaction and heat generation or absorption effects on MHD stagnation-point flow of a nanofluid over a porous stretching sheet. The uniform magnetic field strength B is applied in the direction normal to the flow. A highly nonlinear problem of nanofluid is modeled for the modified Bernoulli's equation of an electrically conducting nanofluid by incorporating the effects of embedded flow parameters such as Brownian motion parameter, thermophoresis parameter, velocity ratio parameter, heat generation/absorption parameter, suction or injection parameter, chemical reaction parameter, Hartmann number, Prandtl number and Lewis number. A system of nonlinear partial differential equations is reduced to nonlinear ordinary differential equations and then solved using finite difference scheme known as the Keller-box method. A parametric study of the involved physical parameters is conducted and a set of numerical results is illustrated in graphical and tabular forms. A comparison with published results is also provided.
Imran Anwar
Abdul Rahman Mohd. Kasim
Zulkhibri Ismail
Mohd. Zuki Salleh
Sharidan Shafie
2015-12-02T02:10:19Z
2018-10-14T08:21:50Z
http://eprints.utm.my/id/eprint/id/eprint/48976
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48976
2015-12-02T02:10:19Z
Heat and mass transfer with free convection MHD flow past a vertical plate embedded in a porous medium
An analysis to investigate the combined effects of heat and mass transfer on free convection unsteady magnetohydrodynamic (MHD) flow of viscous fluid embedded in a porous medium is presented. The flow in the fluid is induced due to uniform motion of the plate. The dimensionless coupled linear partial differential equations are solved by using Laplace transform method. The solutions that have been obtained are expressed in simple forms in terms of elementary function exp(·) and complementary error function erfc(·). They satisfy the governing equations; all imposed initial and boundary conditions and can immediately be reduced to their limiting solutions. The influence of various embedded flow parameters such as the Hartmann number, permeability parameter, Grashof number, dimensionless time, Prandtl number, chemical reaction parameter, Schmidt number, and Soret number is analyzed graphically. Numerical solutions for skin friction, Nusselt number, and Sherwood number are also obtained in tabular forms
Farhad Ali
Ilyas Khan
Sharidan Shafie
Norzieha Musthapa
2015-12-02T02:10:19Z
2018-10-14T08:21:54Z
http://eprints.utm.my/id/eprint/id/eprint/49045
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49045
2015-12-02T02:10:19Z
Heat transfer in a Micropolar fluid over a stretching sheet with Newtonian heating
This article looks at the steady flow of Micropolar fluid over a stretching surface with heat transfer in the presence of Newtonian heating. The relevant partial differential equations have been reduced to ordinary differential equations. The reduced ordinary differential equation system has been numerically solved by Runge-Kutta-Fehlberg fourth-fifth order method. Influence of different involved parameters on dimensionless velocity, microrotation and temperature is examined. An excellent agreement is found between the present and previous limiting results
Muhammad Qasim
Ilyas Khan
Sharidan Shafie
2015-12-02T02:10:19Z
2018-10-14T08:26:48Z
http://eprints.utm.my/id/eprint/id/eprint/50020
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50020
2015-12-02T02:10:19Z
The effects of radiation on free convection flow with ramped wall temperature in Brinkman type fluid
The present paper is on study of the influence of radiation on unsteady free convection flow of Brinkman type fluid near a vertical plate containing a ramped temperature profile. Using the appropriate variables, the basic governing equations are reduced to nondimensional equations valid with the imposed initial and boundary conditions. The exact solutions are obtained by using Laplace transform technique. The influence of radiation near a ramped temperature plate is also compared with the flow near a plate with constant temperature. The numerical computations are carried out for various values of the physical parameters such as velocity, temperature, skin friction and Nusselt number and presented graphically
Muhamad Najib Zakaria
Abid Hussanan
Ilyas Khan
Sharidan Shafie
2015-12-02T02:10:19Z
2018-10-14T08:36:59Z
http://eprints.utm.my/id/eprint/id/eprint/50497
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50497
2015-12-02T02:10:19Z
An exact analysis of heat and mass transfer past a vertical plate with Newtonian heating
An exact analysis of heat and mass transfer past an oscillating vertical plate with Newtonian heating is presented. Equations are modelled and solved for velocity, temperature, and concentration using Laplace transforms. The obtained solutions satisfy governing equations and conditions. Expressions of skin friction, Nusselt number, and Sherwood number are obtained and presented in tabular forms. The results show that increasing the Newtonian heating parameter leads to increase velocity and temperature distributions whereas skin friction decreases and rate of heat transfer increases
Abid Hussanan
Ilyas Khan
Sharidan Shafie
2015-12-02T02:10:18Z
2018-09-27T04:07:12Z
http://eprints.utm.my/id/eprint/id/eprint/49044
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49044
2015-12-02T02:10:18Z
Conjugate effects of heat and mass transfer on MHD free convection flow over an inclined plate embedded in a porous medium
The aim of this study is to present an exact analysis of combined effects of radiation and chemical reaction on the magnetohydrodynamic (MHD) free convection flow of an electrically conducting incompressible viscous fluid over an inclined plate embedded in a porous medium. The impulsively started plate with variable temperature and mass diffusion is considered. The dimensionless momentum equation coupled with the energy and mass diffusion equations are analytically solved using the Laplace transform method. Expressions for velocity, temperature and concentration fields are obtained. They satisfy all imposed initial and boundary conditions and can be reduced, as special cases, to some known solutions from the literature. Expressions for skin friction, Nusselt number and Sherwood number are also obtained. Finally, the effects of pertinent parameters on velocity, temperature and concentration profiles are graphically displayed whereas the variations in skin friction, Nusselt number and Sherwood number are shown through tables
Farhad Ali
Ilyas Khan
Samiulhaq Samiulhaq
Sharidan Shafie
2015-12-02T02:10:15Z
2018-11-30T06:55:21Z
http://eprints.utm.my/id/eprint/id/eprint/49412
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49412
2015-12-02T02:10:15Z
Biologically relevant silver(i)-n-heterocyclic carbene complexes: synthesis, structure, intramolecular interactions, and applications
N-Heterocyclic carbenes (NHCs) complexed with silver represent new, broad-spectrum antimicrobial and anticancer agents, normally with low toxicity profiles, and they provide a range of versatile structures for targeted biological applications. Most of these complexes have shown higher cytotoxicity than cisplatin, a potent anticancer drug. This study reviews the design, synthesis, structural characterization, and biological applications of silver complexes derived from both functionalized and nonfunctionalized NHC ligands. Specifically, silver complexes of functionalized and nonfunctionalized imidazole- and benzimidazole-based NHC systems employed in antimicrobial and anticancer applications are reviewed. Advancements achieved in the use of silver(I)-NHC complexes of miscellaneous azolium ligands, such as 1,2,4-triazole and the heterocycle-fused imidazolium derivative xanthene are also reviewed. Encapsulation of a series of silver-NHC complexes in a polymer-based carrier material represents a promising method for the targeted delivery of silver ions to the infected sites. The advances achieved in this particular area are systematically reviewed in this paper. In general, these preliminary achievements reveal the potential of silver(I)-NHC complexes as efficient antimicrobial and anticancer candidates. NHC ligand design for the formation of mono- and binuclear AgI complexes is reviewed. Particular attention is paid to AgI-NHC complexes that exhibit different biological activities. The effects of different substituents on the structures of the complexes are investigated. AgI complexes with functionalized and nonfunctionalized NHCs are compared.
Srinivasa Budagumpi
Rosenani A. Haque
Salasiah Endud
Ghani Ur Rehman
Abbas Washeel Salman
2015-12-02T02:10:15Z
2018-11-30T06:55:32Z
http://eprints.utm.my/id/eprint/id/eprint/50254
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50254
2015-12-02T02:10:15Z
Birefringence analysis of directional fiber coupler induced by fusion and coupling parameters
The effect of fusion and coupling parameters to the form of birefringence of coupling region directional fiber coupler is reported. Vector of polarization was determined by using perturbation method that describes the propagation of electric field in single mode fiber coupling induced by stress which is caused by fusion and coupling parameters during fabrication. It is found that the geometrical change, such as radius of coupling cross section, refractive index difference, normalized frequency, and twisting angle significantly affect the polarization and birefringence. However, change of temperature during fusion in range 27-1350 C gives only small increment in birefringence directional fiber coupler. By knowing these parameters, the polarization and birefringence can be maintained and optimized for polarization maintaining fiber coupler application.
Dedi Irawan
Saktioto Saktioto
Jalil Ali
Muhammad Fadhali
2015-12-02T02:10:03Z
2018-09-30T08:17:13Z
http://eprints.utm.my/id/eprint/id/eprint/50442
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50442
2015-12-02T02:10:03Z
DNA nanotechnology: a future perspective
In addition to its genetic function, DNA is one of the most distinct and smart self-assembling nanomaterials. DNA nanotechnology exploits the predictable self-assembly of DNA oligonucleotides to design and assemble innovative and highly discrete nanostructures. Highly ordered DNA motifs are capable of providing an ultra-fine framework for the next generation of nanofabrications. The majority of these applications are based upon the complementarity of DNA base pairing: adenine with thymine, and guanine with cytosine. DNA provides an intelligent route for the creation of nanoarchitectures with programmable and predictable patterns. DNA strands twist along one helix for a number of bases before switching to the other helix by passing through a crossover junction. The association of two crossovers keeps the helices parallel and holds them tightly together, allowing the assembly of bigger structures. Because of the DNA molecule's unique and novel characteristics, it can easily be applied in a vast variety of multidisciplinary research areas like biomedicine, computer science, nano/optoelectronics, and bionanotechnology
Muniza Zahid
Byeong Hoon Kim
Rafaqat Hussain
Rashid Amin
Ha Park Sung
2015-12-02T02:10:02Z
2018-10-14T08:21:58Z
http://eprints.utm.my/id/eprint/id/eprint/49125
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49125
2015-12-02T02:10:02Z
Acne vulgarism treatment using ultra-short laser pulse generated by micro- and nano-ring resonator system
Acne vulgaris is adebilitating dermatologic disease, and is conventionally treated by laser therapy using a microring resonator system. An evolving understanding of laser-tissue interactions involving Propioni bacterium acneproducing porphyrins, and the development of lasers to target the sebaceous glands, has led to the development of an escalating number of laser light for acne treatment. The results show that the full width at half maximum of the proposed laser pulse of 0.15 nm can be generated using a microring resonator system. The power of the laser is 200 W and the wavelength laser is 1,032 nm, which is proposed as a treatment of acne vulgaris diseases
Muhammad Arif Jalil
J. Phelawan
M. S. Abdul Aziz
Toto Saktioto
Chee Tiong Ong
Preecha P. Yupapin
2015-12-02T02:09:59Z
2018-09-30T08:17:04Z
http://eprints.utm.my/id/eprint/id/eprint/50003
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50003
2015-12-02T02:09:59Z
EEG signal of epiliptic patient by fast Fourier and wavelet transforms
Electroencephalography (EEG) is one of the field in diagnosing g epilepsy. Analysis of the EEG records can provide valuable insight and improve understanding of the mechanisms causing epileptic disorders. In this paper, the fast Fourier transform (FFT) and wavelet transform are used as spectral analysis tools of the EEG signals. These methods are chosen because they provide time-frequency shifted on the EEG signals. Since the frequency characteristics are important information that can be observed from the signals, FFT and wavelet transform are among a the best methods in analysis of EEG signals. The comparisons between these two methods are also carried out. Result showed that the wavelet transform is better than FFT in analysis of EEG signals. A software for analysing EEG signal is also developed using C++ programming. The software is able to compute and show the results of the analysis signal data by both of the two methods in graphical form
Normah Maan
Chien Yong Goh
Tahir Ahmad
2015-12-02T02:09:59Z
2018-10-14T08:37:00Z
http://eprints.utm.my/id/eprint/id/eprint/50499
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50499
2015-12-02T02:09:59Z
The higher accuracy fourth-order IADE algorithm
This study develops the novel fourth-order iterative alternating decomposition explicit (IADE)method of Mitchell and Fair weather (IADEMF4) algorithm for the solution of the one-dimensional linear heat equation with Dirichlet boundary conditions.The higher order finite difference scheme is developed by representing the spatial derivative in the heat equation with the fourth-order finite difference Crank-Nicolson approximation.This leads to the formation of pentadiagonal matrices in the systems of linear equations. The algorithm also employs the higher accuracy of the Mitchell and Fair weather variant.Despite the scheme’s higher computational complexity, experimental results show that it is not only capable of enhancing the accuracy of the original corresponding method of second-order (IADEMF2), but its solutions are also in very much agreement with the exact solutions. Besides, it is unconditionally stable and has proven to be convergent. The IADEMF4 is also found to be more accurate, more efficient, and has better rate of convergence than the bench marked fourth-order classical iterative methods, namely, the Jacobi (JAC4), the Gauss-Seidel (GS4), and the successive over-relaxation (SOR4) methods
N. Abu Mansor
Ahmad Kamal Zulkifle
Norma Alias
Mohammad Khatim Hasan
M. J. N. Boyce
2015-12-02T02:09:58Z
2018-10-21T04:33:18Z
http://eprints.utm.my/id/eprint/id/eprint/49013
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49013
2015-12-02T02:09:58Z
Aluminium-induced crystallization of silicon thin film by excimer laser annealing
Polycrystalline silicon (poly-Si) film was fabricated by indirect process of re-crystallization of amorphous silicon (a-Si) thin film. This enhancement process is important to determine the performance of silicon thin film (STF). In this attempt, a fundamental study was carried out to enhance the crystallization of aluminium doped silicon thin film. An a-Si thin film was prepared by low pressure physical vapour deposition (PVD) and doped with 10% aluminium. The aluminium-induced crystallization (AIC) process was carried out in two sequence steps. Firstly, the amorphous film was annealed by using conventional heat treatment at operating temperature of 350°C. Secondly, the poly-Si underwent excimer laser anneling (ELA). The micro structure of thin film was analyzed using atomic force microscope (AFM). The results showed that, the grain size of the a-Si film is increased with the energy density of the excimer laser. The optimum grain size obtained is 129 nm corresponding to energy density of 356 mJ cm2
Siti Noraiza Ab. Razak
Noriah Bidin
2015-12-02T02:09:57Z
2018-11-30T06:55:24Z
http://eprints.utm.my/id/eprint/id/eprint/49497
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49497
2015-12-02T02:09:57Z
Bioactivities and cytotoxicities effects of 3',4'-dihydroxy-7-methoxyflavone and 2'-hydroxy-3,4,3',4'-tetramethoxychalcone
Synthetic compounds 3',4'-dihydroxy-7-methoxyflavone (DHMF) and 2'-hydroxy-3,4,3',4'-tetramethoxychalcone (HTMC) were investigated for their antioxidant and anti-tyrosinase activities. Antioxidant activities were evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and Ferric Reducing Ability of Plasma (FRAP) assay. DHMF possessed antioxidant activities with no activity detected for HTMC. Further investigation demonstrates that DHMF possessed greater antioxidant capacity at longer incubation time compared to L-ascorbic acid. In contrast, HTMC demonstrates a novel anti-tyrosinase activity with no activity observed for DHMF. Evaluation on cytotoxicity effects revealed that both synthetic compounds inhibit the viability of CHO and HeLa cells in a concentration-dependent manner with no effect detected at low concentration.
N. A. Ahmad
N. H. Nordin
Muhammad Helmi Nadri
Razauden Mohamed Zulkifli
Farediah Ahmad
Hasnah Mohd. Sirat
2015-12-02T02:09:57Z
2018-10-14T08:36:58Z
http://eprints.utm.my/id/eprint/id/eprint/50461
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50461
2015-12-02T02:09:57Z
3-point pseudo-scale distance measure for measuring indirect proximity
A typical proximity measure employed to find the distance between two points in multidimensional scaling techniques (MDS) is the Euclidean distance. This direct measurement approach however lacks the ability to extract more information from other points in the data. In this paper, we introduce a 3-point pseudo-scale distance measure based on Kendall's tertiary treatment of ties (TTT). This distance is coupled with ANOVA-Tukey's test approach to reveal the hidden structure where the Euclidean distance used in multidimensional scaling technique is not able to cater. To demonstrate the proposed technique, a set of rainfall data recorded between the years 1968 and 2003 over nine rain-gauge stations in Peninsular Malaysia are used
Norliza Adnan
Norhaiza Ahmad
Maiza Hura Ahmad
2015-12-02T02:09:56Z
2018-09-27T04:09:28Z
http://eprints.utm.my/id/eprint/id/eprint/50002
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50002
2015-12-02T02:09:56Z
Cytotoxic activity of major compounds from phaleria macrocarpa (scheff.) Boerl. Fruits
P. macrocarpa is a well known Indonesian medicinal plant which is traditionally claimed to have anticancer properties. To date, there are numerous cytotoxic studies conducted on crude extracts of this plant. However, there are limited informations available regarding cytotoxic activity of the compounds isolated from this plant. Thus, this study investigated cytotoxic activity of two benzophenones derivatives identified as 2,6,4'-trihydroxy-4-methoxybenzophenone (1) and 6,4'-dihydroxy-4-methoxybenzophenone-2-O-β-D-glucopyranoside (2) isolated from the ethyl acetate extract. Cytotoxic activities of these compounds were performed against human cervical carcinoma cell line (HeLa) and mouse embryonic fibroblast cell line (3T3) using MTT assay. The result showed that benzophenone (1) exhibited low cytotoxic effect against HeLa and 3T3 cell lines with IC50 values of 132 µg/ml and 158 µg/ml, repectively while benzophenone (2) was non toxic against HeLa and 3T3 cell lines are because the IC50 is more than 250 µg/ml. These findings may sheds light on the actual properties of this plant
Siti Nur Atiqah Md. Othman
Norazah Basar
Siti Pauliena Mohd. Bohari
2015-12-02T02:09:53Z
2018-10-14T08:26:45Z
http://eprints.utm.my/id/eprint/id/eprint/50000
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50000
2015-12-02T02:09:53Z
An example on computing the irreducible representation of finite metacyclic groups by using great orthogonality theorem method
Representation theory is a study of real realizations of the axiomatic systems of abstract algebra. For any group, the number of possible representative sets of matrices is infinite, but they can all be reduced to a single fundamental set, called the irreducible representations of the group. This paper focuses on an example of finite metacyclic groups of class two of order 16. The irreducible representation of that group is found by using Great Orthogonality Theorem Method
Nizar Majeed Samin
Nor Haniza Sarmin
Hamisan Rahmat
2015-12-02T02:09:53Z
2018-09-27T04:12:15Z
http://eprints.utm.my/id/eprint/id/eprint/50192
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50192
2015-12-02T02:09:53Z
Computing the nonabelian tensor square of metacyclic p-groups of nilpotency class two
In this paper, we develop appropriate programme using Groups, Algorithms and Programming (GAP) software enables performing different computations on various characteristics of all finite nonabelian metacyclic p–groups, p is prime, of nilpotency class 2. Such programme enables to compute structure of the group, order of the group, structure of the center, the number of conjugacy classes, structure of commutator subgroup, abelianization, Whitehead’s universal quadratic functor and other characteristics. In addition, structures of some other groups such as the nonabelian tensor square and various homological functors including Schur multiplier and exterior square can be computed using this programme. Furthermore, by computing the epicenter order or the exterior center order the capability can be determined. In our current article, we only compute the nonabelian tensor square of certain order groups, as an example, and give GAP codes for computing other characteristics and some subgroups
Nor Haniza Sarmin
Nor Muhainiah Mohd. Ali
Abdulqader Mohammed Basri
James R. Beuerle
2015-12-02T02:09:53Z
2018-10-14T08:33:38Z
http://eprints.utm.my/id/eprint/id/eprint/50193
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50193
2015-12-02T02:09:53Z
Fuzzy generalized bi–Γ–ideals of type (λ, θ) in ordered Γ–semigroups
Subscribing to the Zadeh’s idea on fuzzy sets, many researchers strive to identify the key attributes of these sets for new finding in mathematics. In this perspective, we introduce a new concept of fuzzy generalized bi–Γ–ideal of an ordered Γ–semigroup G called a (λ, θ)–fuzzy generalized bi–Γ–ideal ofG. Fuzzy generalized bi–Γ–ideals of type (λ, θ) are the generalization of ordinary fuzzy generalized bi–Γ–ideals of an ordered Γ–semigroup G. A new classification of ordered Γ–semigroups in terms of a (λ, θ)–fuzzy generalized bi–Γ–ideal is given. Furthermore, we proved that U(μ, t) is a generalized bi–Γ–ideal if and only if the fuzzy subset μ is a (λ, θ)–fuzzy generalized bi–Γ–ideal of G for all t ∈(λ,θ]. Similarly, A is a generalized bi–Γ–ideal if and only if the characteristic function μA of A is a (λ, θ)–fuzzy generalized bi–Γ–ideal of G. Finally, the relationship between ordinary fuzzy generalized bi–Γ–ideal and (λ, θ)–fuzzy generalized bi–Γ–ideal is discussed
Faiz Muhammad Khan
Nor Haniza Sarmin
Asghar Khan
2015-12-02T02:09:53Z
2018-10-14T08:33:38Z
http://eprints.utm.my/id/eprint/id/eprint/50195
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50195
2015-12-02T02:09:53Z
The exterior squares of some crystallographic groups
A crystallographic group is a discrete subgroup G of the set of isometries of Euclidean space ,nE where the quotient space nGE is compact. A specific type of crystallographic groups is called Bieberbach groups. A Bieberbach group is defined to be a torsion free crystallographic group. In this paper, the exterior squares of some Bieberbach groups with abelian point groups are computed. The exterior square of a group is the factor group of the nonabelian tensor square with the central subgroup of the group
Hazzirah Izzati Mat Hassima
Nor Haniza Sarmin
Nor Muhainiah Mohd. Ali
Rohaidah Masri
Nor’ashiqin Mohd. Idrus
2015-12-02T02:09:53Z
2018-10-21T04:33:26Z
http://eprints.utm.my/id/eprint/id/eprint/50475
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50475
2015-12-02T02:09:53Z
An alternative technique for computing the commutativity degree of dihedral groups
Let G be a finite dihedral group Dn. The probability that two random elements commute is called the commutativity degree and it is denoted by P(G). Another technique is used to compute the commutativity is using centralizers. The main purpose of this paper is to construct some upper bounds for the commutativity degree in terms of centralizers for the dihedral group, where the dihedral group acts on itself by conjugation
Sanaa Mohamed Saleh Omer
Nor Haniza Sarmin
Ahmad Erfanian
Kayvan Moradipour
2015-12-02T02:09:53Z
2019-01-28T04:30:35Z
http://eprints.utm.my/id/eprint/id/eprint/50490
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50490
2015-12-02T02:09:53Z
Common-crossing and persistent splicing systems
DNA computing is an emerging field that includes the combination of some concepts from biology and computation. Splicing system is a mathematical model in DNA computing which was first introduced by Head in 1987. This model is defined under the framework of formal language theory which is a subcategory of theoretical computer science and applied discrete mathematics. Splicing system stimulates the behavior of restriction enzymes on DNA molecules. In this paper, the concept of Common-Crossing Splicing System is introduced and its properties are investigated. Also, the relation between this splicing system and persistent splicing system is studied.
Fariba Karimi
Nor Haniza Sarmin
Wan Heng Fong
2015-12-02T02:09:50Z
2018-11-30T06:44:09Z
http://eprints.utm.my/id/eprint/id/eprint/49175
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49175
2015-12-02T02:09:50Z
Characterization and performance of hybrid catalysts for levulinic acid production from glucose
In this work, a set of hybrid catalysts were synthesized, characterized and tested for the conversion of glucose to levulinic acid. The hybrid catalysts with 1:1, 1:2 and 2:1 weight ratios of CrCl3 and HY zeolite were prepared via the wetness impregnation method. Characterization of the hybrid catalysts using XRD, FESEM, BET, FT-IR, TGA, NH3-TPD and FT-IR of adsorbed pyridine demonstrated the catalytic reaction of the hybrid catalysts was predominantly influenced by the type of acid sites (Lewis acid), amount of acid sites and strength, surface area, hierarchical porous structures and shape selectivity. Highly reactive acid sites greatly influenced the catalytic activities of glucose in producing levulinic acid. Experimental results revealed that the hybrid 1:1 catalyst exhibited the highest catalytic performance with 62% of levulinic acid yield at 160 °C in 180 min of reaction temperature and time. The hybrid 1:1 catalyst has potential to be applied for biomass conversion to levulinic acid under adequate process conditions.
Nazlina Ya'aini
Nor Aishah Saidina Amin
Salasiah Endud
2015-12-02T02:09:32Z
2018-11-09T08:11:08Z
http://eprints.utm.my/id/eprint/id/eprint/49014
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49014
2015-12-02T02:09:32Z
Application of dispersive liquid-liquid microextraction based on solidification of floating organic droplet to the analysis of antidepressant drugs in water samples
A simple and rapid sample preparation method based on dispersive liquid-liquid microextraction-solidification of floating organic drop (DLLME-SFO) combined with gas chromatography-mass spectrometry (GC-MS) method was developed for the analysis of antidepressant drugs in water samples. This method uses organic solvent with low density and less toxicity. In the method, the disperser solvent (0.5 mL acetonitrile) containing 30 μL of n-hexadecane was rapidly injected using a syringe into 5.0 mL of water sample in a glass tube. After centrifugation for 7 min at 3,500 rpm, the mixture was cooled in ice bath for 5 min. The solidified n-hexadecane was transferred into a conical vial, where it melted rapidly at room temperature and 2 μL of it was injected into a gas Chromatograph for analysis. Under optimized conditions, the method showed good linearity in the range of 0.04 - 0.12 μg mL1 for amitriptyline and chlorpromazine with correlation of determination (r 2) in the range of 0.992 - 0.995. The limits of detections (LODs) were in the range 0.0085 - 0.0285 μg mL-1. The extraction recoveries of amitriptyline and chlorpromazine from water samples at spiking level of 0.08 μg mL-1 were 71.34 - 73.52% and 73.83 - 91.09%, respectively, with relative standard deviations (RSDs) in the range of 4.97-6.85% for amitriptyline and 4.84 - 7.49% for chlorpromazine. The method was successfully applied to the determination of the analytes in drinking water, lake water and tap water samples.
Mohd. Marsin Sanagi
Siti Umairah Mokhtar
Wan Aini Wan Ibrahim
Hassan Y. Aboul Enein
2015-12-02T02:09:26Z
2018-09-27T04:12:20Z
http://eprints.utm.my/id/eprint/id/eprint/50441
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50441
2015-12-02T02:09:26Z
Analytical modeling of trilayer graphene nanoribbon schottky-barrier fet for high-speed switching applications
Recent development of trilayer graphene nanoribbon Schottky-barrier field-effect transistors (FETs) will be governed by transistor electrostatics and quantum effects that impose scaling limits like those of Si metal-oxide-semiconductor field-effect transistor s. The current–voltage characteristic of a Schottky-barrier FET has been studied as a function of physical parameters such as effective mass, graphene nanoribbon length, gate insulator thickness, and electrical parameters such as Schottky barrier height and applied bias voltage. In this paper, the scaling behaviors of a Schottky-barrier FET using trilayer graphene nanoribbon are studied and analytically modeled. A novel analytical method is also presented for describing a switch in a Schottky-contact double-gate trilayer graphene nanoribbon FET. In the proposed model, different stacking arrangements of trilayer graphene nanoribbon are assumed as metal and semiconductor contacts to form a Schottky transistor. Based on this assumption, an analytical model and numerical solution of the junction current–voltage are presented in which the applied bias voltage and channel length dependence characteristics are highlighted. The model is then compared with other types of transistors. The developed model can assist in comprehending experiments involving graphene nanoribbon Schottky-barrier FETs. It is demonstrated that the proposed structure exhibits negligible short-channel effects, an improved on-current, realistic threshold voltage, and opposite subthreshold slope and meets the International Technology Roadmap for Semiconductors near-term guidelines. Finally, the results showed that there is a fast transient between on-off states. In other words, the suggested model can be used as a high-speed switch where the value of subthreshold slope is small and thus leads to less power consumption
Meisam Rahmani
Mohammad Taghi Ahmadi
Hediyeh Karimi Feiz Abadi
Mehdi Saeidmanesh
Elnaz Akbari
Razali Ismail
2015-12-02T02:09:25Z
2018-11-30T06:55:40Z
http://eprints.utm.my/id/eprint/id/eprint/50664
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50664
2015-12-02T02:09:25Z
Calculation of vg(9/2) + isomers in 65Ni, 67Zn,69Ge and 71Se nuclei
We have calculated the reduced transition probabilities B(M2, 9/2+ → 5/2-) of odd 65Ni, 67Zn, 69Ge, and 71Se nuclei with neutron number N=37. The theoretical calculations of the reduced transition probabilities are compared with the experimental values. The width of isomeric levels, mean-life of isomers, and Weisskopf hindrance factors of those nuclei were calculated. The systematic isomeric levels are plotted as a function of odd mass number and indicated that isomeric level decreases with an increase in the mass number.
Nik Noor Aien Mohamed Abdul Ghani
Imam Hossain
Mohammad Alam Saeed
Hewa Y. Abdullah
Magdy Hussein
2015-12-02T02:09:20Z
2018-10-31T12:37:20Z
http://eprints.utm.my/id/eprint/id/eprint/49168
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49168
2015-12-02T02:09:20Z
Annealing time dependent up-conversion luminescence enhancement in magnesium-tellurite glass
Silver nanoparticles (NPs) embedded Er3+ ions doped magnesium-tellurite glasses are prepared using melt quenching technique. Heat treatment with different time intervals above the glass transition temperature is applied in order to reduce the silver ions (Ag+) to silver NPs (Ago). The transmission electron microscopy (TEM), differential thermal analyses (DTA), UV-vis-NIR absorption spectroscopy and photoluminescence (PL) spectroscopy are used to examine annealing time dependent structural and optical properties. The characteristics temperatures such as glass transition temperature (Tg), crystallization temperature (Tc) and melting temperature (Tm) obtained from DTA for an as prepared sample are 322 °C, 450 °C and 580 °C, respectively. TEM image clearly shows the homogeneous distribution of silver NPs with an average diameter ∼12 nm. The observed localized surface plasmon resonance (LSPR) band is evidenced at 534 nm. Furthermore, the infrared to visible frequency up-conversion (UC) emission under 786 nm excitation exhibits three emission bands centered at 532 nm, 554 nm and 634 nm corresponding to 2H11/2→ 4I15/2, 4S3/2→ 4I15/2 and 4F9/2→ 4I15/2 transitions of Er3+, respectively. Intensity of all the bands is found to enhance by increasing the annealing time up to 24 h. However, further increase in the annealing time duration (∼40 h) reduces the intensity. Enhancement in the luminescence intensity is understood in terms of the local field effect of the silver NPs whereas the quenching is attributed to the energy transfer from Er3+ ions to silver NPs
Raja Junaid Amjad
Md. Rahim Sahar
Sib Krishna Ghoshal
Mohammad Reza Dousti
S. Riaz
Alireza R. Samavati
Ramli Arifin
Shahzad Naseem
2015-12-02T02:09:16Z
2018-10-21T04:33:27Z
http://eprints.utm.my/id/eprint/id/eprint/50476
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50476
2015-12-02T02:09:16Z
Analysis of a correlation network in world currency exchange market
This paper analyses a correlation network of world currency exchange rate. We examine the network topology of 54 foreign currency exchange rate from 2009-2012 by using the minimum spanning tree method. The approach developed by Mantegna in 1999 has been used to transform the correlation matrix into distance matrix. We perform a network analysis based on centrality measures in order to understand currency's behavior and also identify the most influential currencies
Mansooreh Kazemilari
Maman Abdurachman Djauhari
2015-12-02T02:08:52Z
2018-10-14T08:26:35Z
http://eprints.utm.my/id/eprint/id/eprint/49697
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49697
2015-12-02T02:08:52Z
Generation of potential wells used for quantum codes transmission via a TDMA network communication system
This paper proposes a technique of quantum code generation using optical tweezers. This technique uses a microring resonator made of nonlinear fibre optics to generate the desired results, which are applicable to Internet security and quantum network cryptography. A modified add/drop interferometer system called PANDA is proposed, which consists of a centred ring resonator connected to smaller ring resonators on the left side. To form the multifunction operations of the PANDA system-for instance, to control, tune and amplify-an additional Gaussian pulse is introduced into the add port of the system. The optical tweezers generated by the dark soliton propagating inside the PANDA ring resonator system are in the form of potential wells. Potential well output can be connected to the quantum signal processing system, which consists of a transmitter and a receiver. The transmitter is used to generate high-capacity quantum codes within the system, whereas the receiver detects encoded signals known as quantum bits. Therefore, an entangled photon pair can be generated and propagated via an optical communication link such as a time division multiple access system. Here, narrower potential wells with a full-width half-maximum of 3.58 and 9.57nm are generated at the through and drop ports of the PANDA ring resonator system, respectively, where the amplification of the signals occurs during propagation inside the system. Copyright © 2013 John Wiley & Sons, Ltd. A PANDA ring resonator system which is made of nonlinear fiber optic can be used to generate optical tweezers in the form of potential wells while the dark soliton propagates inside the system. This system is connected to an encoding unit in which entangled photon pair can be generated and propagated via an optical communication link such as a time division multiple access. Here, ultra-short potential wells with a full-width halfmaximum of 3.58 and 9.57nm could be generated
Iraj Sadegh Amiri
Mehrnaz Nikmaram
Ali Shahidinejad
Jalil Ali
2015-12-02T02:08:45Z
2018-09-27T04:07:21Z
http://eprints.utm.my/id/eprint/id/eprint/49079
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49079
2015-12-02T02:08:45Z
Cox-2 inhibitors from stem bark of Bauhinia rufescens lam. (Fabaceae)
Chemical investigation of the stem bark of Bauhinia rufescens resulted in the isolation of a new cyanoglucoside and menisdaurin from methanol extract and oxepin from petroleum ether extract. The isolated compounds were tested for their anti-inflammatory potentials based on the cyclooxygenase-2 enzyme (COX-2) model. Cyanoglucoside exhibited the highest activity among the compounds with an inhibition activity of 49.34% at 100 μM (IC50 0.46 μM) compared to the positive control, indomethacin (79.20%, IC50 0.24 μM)
Hasnah Mohd. Sirat
Aminu Muhammad
2015-12-02T02:08:45Z
2018-11-30T06:55:16Z
http://eprints.utm.my/id/eprint/id/eprint/49360
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49360
2015-12-02T02:08:45Z
Assessment of theoretical methods for the study of hydrogen abstraction kinetics of global warming gas species during their degradation and byproduct formation (IUPAC technical report)
Global climate change is a major concern as it leads to an increase in the average temperature of the earth's atmosphere. The existence and persistence of some gaseous species in the atmosphere contribute to global warming. Experimental techniques are used to study the kinetics and degradation of global warming gases. However, quantum mechanical methods are also useful for the kinetic and radiative forcing study of global warming species and can precede experimental investigations. Research has also been targeted to develop more adapted procedures using ab initio and density functional theory (DFT) methods. This report provides a global perspective, in simplified manner, of the theoretical studies of the degradation of gas species in the atmosphere with an emphasis on the hydrogen abstraction kinetics of global warming gas species during their degradation and byproduct formation. En route, the results obtained from these studies are analysed and compared with experimental data where available. Our analyses indicate that the theoretical predictions are in agreement with experimental findings but the predicted parameters are dependent on the method being used. Theoretical methods are used to predict the thermodynamic parameters of reactions, and, with relevance to this report, the global warming potential (GWP) index can also be calculated. This report can be useful for future investigations involving global warming gaseous species while providing suggestions on how computations can fill in data gaps when experimental data are unavailable.
Ponnadurai Ramasami
Hassan Hadi Abdallah
Edet F. Archibong
Paul Blowers
Thomas A. Ford
Rita Kakkar
Zhigang Shuai
Henry F. Schaefer
2015-12-02T02:08:44Z
2019-01-28T04:30:36Z
http://eprints.utm.my/id/eprint/id/eprint/50549
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50549
2015-12-02T02:08:44Z
Chemical constituents of the leaf of Alpinia mutica roxb
Hydrodistillation of the fresh leaves of Alpinia mutica afforded 0.005% colourless essential oil. GC and GC-MS analysis revealed the presence of 33 components accounting for 92.9% of the total oil, dominated by 20 sesquiterpenes (76.7%) and 10 monoterpenes (8.3%). The major constituent was found to be -sesquiphellandrene which was 29.2% of the total oil. Soxhlet extraction, followed by repeated column chromatography of the dried leaves yielded two phenolic compounds, identified as 5,6-dehydrokawain and aniba dimer A, together with one amide assigned as auranamide. The structures of these compounds were determined by using spectroscopic analysis. Antibacterial screening of the essential oil, the crude and isolated compounds showed weak to moderate inhibitory activity.
Hasnah Mohd. Sirat
Nor Akmalazura Jani
2015-12-02T02:08:42Z
2018-10-14T08:22:07Z
http://eprints.utm.my/id/eprint/id/eprint/49251
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49251
2015-12-02T02:08:42Z
Manufacturing and morphological analysis of composite material of polystyrene nanospheres/cadmium metal nanoparticles
A very simple nanocomposite material has been in-situ manufactured from an aqueous polystyrene nanospheres dispersion and cadmium (Cd) metal nanoparticles. The manufacturing was performed by using a high frequency of 40 kHz ultrasonic (US) agitation for 45 minute at atmospheric pressure and at room temperature 20 oC. No chemical reducing agent and surfactant added in this manufacturing technique due to the US could reduce Cd2+ ions of cadmium nitrate tetrahydrate to Cd atomic metals nanoparticles whereas water molecules could act as a pseudo stabilizer for the manufactured material. A thin film was manufactured from aqueous colloidal nanocomposite material of Polystyrene nanospheres/Cd metal nanoparticles (PSNs/CdMNp) fabricated on a hydrophilic silicon wafer. The thin film was then characterized by a JEOL-FESEM for its surface morphology characteristic and by ATR-FTIR spectrometry for its molecular change investigation. It could be clearly observed that surface morphology of the thin film material was not significantly changed under 633 nm wavelength continuous laser radiation exposure for 20 minute. In addition, its ATR-FTIR spectra of wave number peaks around 3400 cm-1 have been totally disappeared under the laser exposure whereas that at around 699 cm-1 and 668 cm-1 have not been significantly changed. The first phenomenon indicated that the hydrogen bond existed in PSNs/CdMNp material was collapsed by the laser exposure. The second phenomena indicated that the PSNs phenyl ring moiety was not totally destroyed under the laser exposure. It was suspected due to the existence of Cd nanoparticles covered throughout the spherical surface of PSNs/CdMNp material particles. Therefore a nice model of material structure of the mentioned PSNs/CdMNp nanocomposite material could be suggested in this research. It could be concluded that this research have been performed since the material structure model of the manufactured PSNs/CdMNp nanocomposite could be drawn and proposed
Pratama Jujur Wibawa
Hashim Saim
Mohd. Arif Agam
Hadi Nur
2015-12-02T02:08:37Z
2018-10-14T08:26:47Z
http://eprints.utm.my/id/eprint/id/eprint/50008
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50008
2015-12-02T02:08:37Z
Hybrid of ARIMA-GARCH modeling in rainfall time series
The dependence structure of rainfall is usually very complex both in time and space. It is shown in this paper that the daily rainfall series of Ipoh and Alorsetar are affected by nonlinear characteristics of the variance often referred to as variance clustering or volatility, where large changes tend to follow large changes and small changes tend to follow small changes. In most empirical modeling of hydrological time series, the focus was on modeling and predicting the mean behavior of the time series through conventional methods of an Autoregressive Moving Average (ARMA) modeling proposed by the Box Jenkins methodology. The conventional models operate under the assumption that the series is stationary that is: constant mean and either constant variance or season-dependent variances, however, does not take into account the second order moment or conditional variance, but they form a good starting point for time series analysis. The residuals from preliminary ARIMA models derived from the daily rainfall time series were tested for ARCH behavior. The autocorrelation structure of the residuals and the squared residuals were inspected, the residuals are uncorrelated but the squared residuals show autocorrelation, the Ljung-Box test confirmed the results. McLeod-Li test and a test based on the Lagrange multiplier (LM) principle were applied to the squared residuals from ARIMA models. The results of these auxiliary tests show clear evidence to reject the null hypothesis of no ARCH effect. Hence indicates that GARCH modeling is necessary. Therefore the composite ARIMA-GARCH model captures the dynamics of the daily rainfall series in study areas more precisely. On the other hand, Seasonal ARIMA model became a suitable model for the monthly average rainfall series of the same locations treated
Fadhilah Yusof
Ibrahim Lawal Kane
Zulkifli Yusop
2015-12-02T02:08:37Z
2018-11-30T06:55:34Z
http://eprints.utm.my/id/eprint/id/eprint/50332
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50332
2015-12-02T02:08:37Z
Characterisation of drought properties with bivariate copula analysis
Drought severity and duration are usually modelled independently. However, these two characteristics are known to be related. To model this relationship, a joint distribution of drought severity and duration using a bivariate copula model is proposed and applied to daily rainfall data (1976-2007) of 30 rain gauge stations in Peninsular Malaysia. The drought characteristics are classified using the standardized precipitation index (SPI) and their univariate marginal distributions are further identified by fitting exponential, gamma, generalized extreme value, generalized gamma, generalized logistics, generalized pareto, gumbel max, gumbel min, log-logistic, log-pearson3, log-normal, normal, pearson 5, pearson 6 and weibull distributions. The three-parameter log-normal distribution is identified as the best fitting distribution for drought severity while the generalized pareto distribution is determined as the most appropriate distribution for drought duration with respect to the application of the Anderson-Darling procedure. The dependency among the drought properties is analysed using Kendall's τ method. The maximum likelihood estimation of the univariate marginal distributions and the maximisation of the bivariate likelihood are employed to compute the Akaike Information Criterion (AIC) values in verifying the best fitting copula distribution. The Galambos distribution is recognised as the most appropriate copula distribution for describing the relationship between drought severity and duration. The conditional drought probability and drought return period are further described to explain the drought properties comprehensively. The probabilities of drought occurrences under certain circumstances with a specific seriousness or duration can be determined in order to verify the possibility of drought episodes. The return period of a recurrent drought has also been investigated to identify the time-interval for repeated drought occurrences under similar situation.
Fadilah Yusof
Hui Mean Foo
Shariifah Suhaila Syed Jamaludin
Zulkifli Yusof
2015-12-02T02:08:27Z
2018-09-27T04:09:28Z
http://eprints.utm.my/id/eprint/id/eprint/50001
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50001
2015-12-02T02:08:27Z
Characterization of bacillus licheniformis strain Ta62bi as potential selective plugging agent for enchanced oil recovery
Bacterial plugging agents for microbial enhanced oil recovery were peviously studied using non-hydrocarbon substrate. They lacked the ability to survive and form stable plug at high concentration of hydrocarbon compounds. As an alternative, hydrocarbon was used as substrate to determine the bacterial potential as plugging agent. In this study, Bacillus licheniformis Ta62bi was used to study the potential of the bacteria as plugging agent in polycyclic aromatic hydrocarbon (PAH)-rich condition. Three responses (growth, exopolysaccharides (EPS) and PAH consumption) were analyzed. The survivability pattern was observed at 72 hours. From the analysis, pyrene was the best PAH compared to naphthalene. It was based on increment of 214% (415 CFU/mL) in growth and 30% (0.759 g/L) in EPS production. However, the consumption of soluble PAH (0.002 to 0.015 mg/L) was low. The assimilation of hydrocarbon by potential bacterial plugging agent is the only means of survival. Otherwise, it would degrade to a great extent the oil components that would lead to the reduction of the oil quality. Next, a two-level factorial design was conducted to analyze the effects of different concentration of pyrene (0.1 to 10 g/L) and temperatures (27°C to 50°C) to the responses. The results showed that both factors significantly affect the responses (P < 0.05). Both factors inhibited growth of bacterium Ta62bi. As the PAH concentration was increased, the EPS production and PAH consumption was also found to increase at 27˚C. At 50°C, there was an increase in the EPS production but not in the PAH consumption. Therefore, EPS might be implied to having an important role in the tolerance of the TA62bi strain towards hydrocarbon. The findings will be further used in future research as a model to predict and control enhanced oil recovery plugging mechanism
Fareh Nunizawati Daud
Mohd. Nazrin Johari
Arifah Bahar
Ahmad Kamal Idris
Adibah Yahya
2015-12-02T02:08:26Z
2018-10-21T04:33:23Z
http://eprints.utm.my/id/eprint/id/eprint/49753
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49753
2015-12-02T02:08:26Z
An analysis of annual maximum streamflows in Terengganu, Malaysia using TL-moments approach
TL-moments approach has been used in an analysis to determine the best-fitting distributions to represent the annual series of maximum streamflow data over 12 stations in Terengganu, Malaysia. The TL-moments with different trimming values are used to estimate the parameter of the selected distributions namely: generalized pareto (GPA), generalized logistic, and generalized extreme value distribution. The influence of TL-moments on estimated probability distribution functions are examined by evaluating the relative root mean square error and relative bias of quantile estimates through Monte Carlo simulations. The boxplot is used to show the location of the median and the dispersion of the data, which helps in reaching the decisive conclusions. For most of the cases, the results show that TL-moments with one smallest value was trimmed from the conceptual sample (TL-moments (1,0)), of GPA distribution was the most appropriate in majority of the stations for describing the annual maximum streamflow series in Terengganu, Malaysia
Ummi Nadiah Ahmad
Ani Shabri
Zahrahtul Amani Zakaria
2015-12-02T02:08:22Z
2018-09-27T04:12:22Z
http://eprints.utm.my/id/eprint/id/eprint/50469
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50469
2015-12-02T02:08:22Z
A boundary integral equation with the generalized neumann kernel for a mixed boundary value problem in unbounded multiply connected regions
In this paper we propose a new method for solving the mixed boundary value problem for the Laplace equation in unbounded multiply connected regions. All simple closed curves making up the boundary are divided into two sets. The Dirichlet condition is given for one set and the Neumann condition is given for the other set. The mixed problem is reformulated in the form of a Riemann-Hilbert (RH) problem which leads to a uniquely solvable Fredholm integral equation of the second kind. Three numerical examples are presented to show the effectiveness of the proposed method
Samer A. A. Al-Hatemi
Ali Hassan Mohamed Murid
Mohamed M. S. Nasser
2015-12-02T02:08:22Z
2018-11-30T06:55:35Z
http://eprints.utm.my/id/eprint/id/eprint/50477
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50477
2015-12-02T02:08:22Z
Boundary integral equations with the generalized Neumann kernel for robin problem in simply connected region
A mixed boundary value problem with the linear combination of Dirichlet and Neumann conditions is called a Robin problem. In this paper, we consider the Robin problem in a bounded simply connected region G with smooth boundary ωG. It consists of finding a function u harmonic in G and satisfies the Robin boundary condition. This work develops new boundary integral equations for solving the Robin problem. Recently, the interplay of Riemann-Hilbert problems (briefly, RH problems) with conformal mapping, Dirichlet problem and Neumann problem has been studied extensively. The related integral equations involving the generalized Neumann kernel are uniquely solvable. In this paper we show how to reformulate a Robin problem as a Riemann-Hilbert problem. Numerical results are presented to illustrate the solution technique for the Robin problem when the boundaries are sufficiently smooth.
Amir S. A. Hamzah
Ali Hassan Mohamed Murid
Mohamed M. S. Nasser
2015-12-02T02:08:21Z
2019-01-28T04:30:28Z
http://eprints.utm.my/id/eprint/id/eprint/49399
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49399
2015-12-02T02:08:21Z
Chemical modification of chitin by grafting with polystyrene using ammonium persulfate initiator
Chitin was successfully grafted with polystyrene by free radical mechanism using ammonium persulfate (APS) initiator. The reaction was carried out in aqueous medium. The effect of pH, chitin:monomer weight ratio, APS, reaction time and reaction temperature were investigated. The results showed that the optimum conditions for grafting of polystyrene were found as follows: pH 7, chitin:monomer weight ratio of 1:3, 0.4 g of APS, reaction temperature of 60 C and reaction time 2 h. The graft copolymer was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) and differential scanning electron microscopy (DSC). Gel permeation chromatography (GPC) analysis carried out on the hydrolyzed graft copolymer showed that the Mn and Mw were 6.3395 × 104 g/mol and 1.69283 × 105 g/mol, respectively, with polydispersity index of 2.7.
Ahmedy Abu Naim
Abdulganiyu Umar
Mohd. Marsin Sanagi
Noraimi Basaruddin
2015-12-02T02:08:20Z
2018-11-09T08:11:24Z
http://eprints.utm.my/id/eprint/id/eprint/50374
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50374
2015-12-02T02:08:20Z
Assessment of environmental ra-226, th-232 and k-40 concentrations in the region of elevated radiation background in Segamat District, Johor, Malaysia
Extensive environmental survey and measurements of gamma radioactivity in the soil samples collected from Segamat District were conducted. Two gamma detectors were used for the measurements of background radiation in the area and the results were used in the computation of the mean external radiation dose rate and mean weighted dose rate, which are 276nGyh-1 and 1.169mSvy-1, respectively. A high purity germanium (HPGe) detector was used in the assessment of activity concentrations of 232Th, 226Ra and 40K. The results of the gamma spectrometry range from 11±1 to 1210±41Bqkg-1 for 232Th, 12±1 to 968±27Bqkg-1 for 226Ra, and 12±2 to 2450±86Bqkg-1 for 40K. Gross alpha and gross beta activity concentrations range from 170±50 to 4360±170Bqkg-1 and 70±20 to 4690±90Bqkg-1, respectively. These results were used in the plotting of digital maps (using ARCGIS 9.3) for isodose. The results are compared with values giving in UNSCEAR 2000.
Muneer Aziz Saleh
Ahmad Termizi Ramli
Yasser Alajerami
Abubakar Sadiq Aliyu
2015-12-02T02:08:15Z
2018-09-27T04:07:28Z
http://eprints.utm.my/id/eprint/id/eprint/49460
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/49460
2015-12-02T02:08:15Z
Degradation of ampicillin and penicillin G using anodic oxidation
The degradation of ampicillin and penicillin G has been carried out by oxidation method using mixed metal oxides (MMO) electrodes as the anode. The objective of this paper was to study the electrochemical properties of several types of antibiotic drugs using electroanalytical techniques and to evaluate the efficiency of commercial MMO electrodes for the degradation of the drugs by anodic oxidation. For electrochemical studies, the determination of ampicillin and penicillin G has been carried out by differential pulse cathodic stripping voltammetry (DPCSV) at a hanging mercury drop electrode (HMDE) using Britton Robinson buffer (BRB). Ampicillin showed a clear peak current at potential -0.25 V at BRB pH 7 with initial and accumulation potential of 0 V, accumulation time of 30 seconds and with 0.02 V/s of scan rate. For penicillin G determination, the following optimum conditions were used: BRB pH 12, initial potential -0.3 V, accumulation potential of 0 V, and accumulation time of 30 seconds with 0.02 V/s of scan rate. For electrodegradation studies, two mixed metals oxide (MMO) titanium based electrodes have been used in three different mediums: BRB pH 4, tap water and BRB pH 10. For MMO electrode based on (Ru-Ir-TiO2 (20:30:50)-10 micron), the best medium for degradation of ampicillin was at pH 4 with 100 % degradation in 15 minutes: for penicillin G, pH 10 is the best medium for the degradation. For (Ru-Ir-TiO2 (40:10:50)-10 micron, similar results were obtained i.e. pH 4 was the best medium for ampicillin and pH 12 for penicillin G
Mohd. Dzul Hakim Wirzal
Abdull Rahim Mohd. Yusoff
Jiri Zima
Jiri Barek
2015-12-02T02:08:15Z
2018-10-21T04:33:25Z
http://eprints.utm.my/id/eprint/id/eprint/50297
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/50297
2015-12-02T02:08:15Z
Utilizing distributed learning automata to solve the connected target coverage problem in directional sensor networks
Sensor networks have been employed in a variety of applications. Directional sensor networks (DSNs) are a class of sensor networks that have emerged more recently and received noticeable attention from scholars. One of the most significant challenges associated with DSNs is designing an effective algorithm to cover all the targets and, at the same time, retain connectivity with the sink. As sensors are often densely deployed, employing scheduling algorithms can be considered as a promising approach. In this paper, we use distributed learning automata (DLA) to design a new scheduling algorithm for solving the connected target coverage problem in DSNs. The proposed algorithm employs DLA to determine the sensors that should be activated at each stage for monitoring all the targets and transmitting the sensing data to the sink. In addition, we devise several pruning rules in order to maximize network lifetime. Extensive simulation experiments were carried out to evaluate the performance of the proposed algorithm. Simulation results demonstrated the superiority of the proposed algorithm over a greedy-based algorithm in terms of extending network lifetime
Hosein Mohamadi
Abdul Samad Ismail
Shaharuddin Salleh
2015-10-15T01:09:45Z
2015-10-15T01:09:45Z
http://eprints.utm.my/id/eprint/id/eprint/48274
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48274
2015-10-15T01:09:45Z
Preparation and characterization of LiFePO4-based cathode materials prepared by template method for lithium ion batteries
Wan Rosemaria Nurul Huda Wan Baharom
2015-10-15T01:09:45Z
2015-10-15T01:09:45Z
http://eprints.utm.my/id/eprint/id/eprint/48293
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48293
2015-10-15T01:09:45Z
Systhesis and characterization of alumnium doped zinc oxide nanowires on non-catalytic silica substrates
Tashi Jordi
2015-10-15T01:09:44Z
2017-06-20T02:55:38Z
http://eprints.utm.my/id/eprint/id/eprint/48174
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48174
2015-10-15T01:09:44Z
Characterization of lithium-magnesium-tellurite doped with erbium and neodymium glass
Tellurite glass based on (78-x)TeO2-10Li2O-10MgO-2Nd2O3-xEr2O3, (where x = 0.4 to 2.0 mol %) has successfully been prepared by melt-quenching technique. The colour of glass is found to vary from light violet to dark violet as the Er2O3 content is increased. No definite peaks are found from the X-ray diffraction pattern, which shows that the glass is amorphous in nature. It also found that the densities and the molar volume of the glass increase as the Er2O3 content is increased. The glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm) and the temperature difference (Tc-Tg) are determined by means of Differential Thermal Analysis (DTA). It is found that the Tc, Tg and Tm are in the range of (419-430) oC, (300-345) oC and (885-890) oC respectively. Meanwhile, the vibrational study is conducted using the Infrared spectroscopy in the range of (4000-400) cm–1. Two major absorption peaks are observed around (1600-3600) cm–1, and (900-1200) cm–1 which are due to the stretching mode vibration of OH peak and Te-OH peak respectively. The optical absorption edge is studied using UV-Vis spectroscopy. The result shows that the optical band gap (Eopt) and Urbach Energy (?E) are in the range of (3.038-3.130) eV and (0.334-0.321) eV respectively, depending on the Er2O3 concentration. The refractive index is evaluated using the Sellmeier’s equation and it is found that the value in the visible region is in the range of 1.724-1.781 depending on the Er2O3 content. The emission spectrum is recorded using the photoluminescence spectrometer excited at 582 nm at room temperature. The result shows that the emission spectrum of Er3+ and Nd3+ consist of five emission bands at ~457 nm, ~495 nm, ~556 nm, ~611 nm, and ~ 665 nm which can be assigned as a transition of 4F7/2?4F15/2, 4S3/2?4F15/2, 4G11/2 ? 4I9/2, 4G11/2 ? 4I15/2 and 4G7/2 ? 4I13/2 respectively
Syaridatul Akmar Roslan
2015-10-15T01:09:44Z
2017-09-19T04:05:20Z
http://eprints.utm.my/id/eprint/id/eprint/48239
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48239
2015-10-15T01:09:44Z
Model peralihan jisim serentak bagi titisan-titisan yang pelbagai saiz
Liquid-liquid extraction is one of the important transfer operations in chemical engineering. In the design of extraction equipment, basic understanding of the mechanism of mass transfer between disperse phase and the continuous phase is very important. Typically, this problem is solved by means of measuring the mass transfer rate obtained from rotating disc extraction column (RDC) that was predicted by the model of simultaneous mass transfer. Because the mass transfer rate depends on several factors which sometimes can not be measured accurately, as the form of drops, drop size and the differences that occur in the RDC column. This study focuses on the modeling of the diffusion problem in different sizes of drop size in a stage of RDC column using the concept of diffusion in spherical drop with the assumption that the diffusion process from the continuous phase to the disperse phase occur simultaneously. Next, the simulation process for the mass transfer process of 10 drops with various sizes in a stage is done using simultaneous mass transfer model
Syafikah Ayob
2015-10-15T01:09:44Z
2015-10-15T01:09:44Z
http://eprints.utm.my/id/eprint/id/eprint/48292
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48292
2015-10-15T01:09:44Z
Synthesis, characterization and catalytic activity of chiral mesoporous silica for asymmetric reaction
Syaidatul Shafiqah Yusrirohani
2015-10-15T01:09:43Z
2017-08-24T01:42:42Z
http://eprints.utm.my/id/eprint/id/eprint/48161
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48161
2015-10-15T01:09:43Z
Anion recognition properties of poly(amidoamine) dendrimer functionalized with hamilton receptor moiety in aqueous solutions containing nitrate and nitrite ions
Rosliana Rusli
2015-10-15T01:09:43Z
2017-08-29T01:56:21Z
http://eprints.utm.my/id/eprint/id/eprint/48186
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48186
2015-10-15T01:09:43Z
Discrete adomian decomposition method for solving fredholm integral equations of the second kind
The nonlinear Fredholm integral equation (FIE) represents a large amount of nonlinear phenomena that usually produces a considerable amount of difficulties. This dissertation will display some methods used for solving this problem, such as an Adomian Decomposition Method (ADM) which is based on decomposing the solution to infinite series and numerical implementation of ADM for the special case when the kernel is separable. In addition, it discusses the process of applying the Discrete Adomian Decomposition Method (DADM) which gives the numerical solution at the nodes using quadrature rules like Simpsons rule and trapezoidal rule. The comparison of DADM with of both rules with the exact solution also are given. Furthermore the results from DADM, Triangles orthogonal functions (Tfs) and Rationalized Haar function (RHf) for two dimensional linear and nonlinear FIE of the second kind respectively are compared with exact solution. Hence the results obtained show equivalent accuracy when linear FIE of the second kind for two dimension were solved by DADM with Simpson’s rule and by Tfs. Whereas the results show of DADM with Simpson’s rule is more accurate than RHf to solve nonlinear FIE of the second kind for 2-D
Salar Hameed Mohammed
2015-10-15T01:09:43Z
2015-10-15T01:09:43Z
http://eprints.utm.my/id/eprint/id/eprint/48291
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48291
2015-10-15T01:09:43Z
Symmetric and asymmetric garch models for forecasting the prices of gold
Pung, Yean Ping
2015-10-15T01:09:42Z
2017-08-28T01:29:19Z
http://eprints.utm.my/id/eprint/id/eprint/48165
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48165
2015-10-15T01:09:42Z
Application of multi-criteria decision making method in seletion of academic staff at Faculty of Science, Universiti Teknologi Malaysia
The selection of academic staff is important process for the university because the decision will affect the quality and the success of the university. Academic staff is the professional career as they are person who have the high skills in their respective fields. It is not easy for the selection committee to select appropriate personnel as they always faces up to uncertainty decision making process. Two Multiple Criteria Decision Making (MCDM) method namely Analytic Hierarchy Process (AHP) and Elimination and Choice Translating Reality I (ELECTRE I) are adopted to enable the decision makers to make effective decision in selecting academic staff. Both methods helps permit pair-wise comparison judgments in expressing the relative priority for criteria and alternatives that is translated from qualitative to quantitative data by considering the criteria that influence decision made. This study has applied six main criteria and fifteen sub-criteria for selecting the best one amongst seven candidates for the academic staff position in the Faculty of Science, UTM. The selection criteria of Academic, General Attitudes, Interpersonal Skill, Experience, Extracurricular Activities, and Referees Report that used in this study are determined based on some literature reviews and knowledge acquisition by interview Deputy Registrar from Registrars‘ Office and Assistant Registrar from Faculty of Science, UTM. By applying both methods, Candidate 7 should be selected as academic staff since she possesses the first rank of the generated candidate profile. Expert Choice 11.0 and Microsoft Excel 2007 are used to assist in accomplishing the calculation involved. As a suggestion for future work, other researches could apply the other of MCDM method in selecting academic staff.
Nurul Duratulain Ramlan
2015-10-15T01:09:42Z
2017-09-17T07:15:28Z
http://eprints.utm.my/id/eprint/id/eprint/48213
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48213
2015-10-15T01:09:42Z
Grammar systems in simple splicing
Nurul 'Alyaa' Shukri
2015-10-15T01:09:42Z
2017-09-18T08:57:10Z
http://eprints.utm.my/id/eprint/id/eprint/48236
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48236
2015-10-15T01:09:42Z
Measurement of radon-222 and radium-226 in well water of Kelantan
The Environmental Protection Agency (EPA) of USA sets the Maximum Contamination Level (MCL) for 222Rn in drinking water to be 11.1000 Bq/l and for 226Ra to be 0.1100 Bq/l. This study was conducted to determine the levels of 222Rn and 226Ra in private well water in the state of Kelantan. A total of 25 samples of well water were collected from various districts in the state. The levels of 222Rn and 226Ra dissolved in well water were measured using the liquid scintillation counting technique. 222Rn activity concentrations were found within the range of 0.0491 to 4.3127 Bq/l for both unfiltered and filtered samples. Meanwhile, activity concentration of 226Ra measured is between 0.0278 to 1.9670 Bq/l for both unfiltered and filtered samples, exceeding the MCL value. The annual effective doses due to the intake of natural radionuclide from well water for three different age groups were estimated based on the amount of water consumed. The average annual effective dose of 226Ra calculated for babies in the range of 0.12 to 1.79 ^Sv/y. The average annual effective dose of 226Ra for children was in the range of 0.11 to 0.34 ^Sv/y while, for the adults, it was in the range of 0.11 to 0.33 ^Sv/y for 226Ra. The annual effective dose intake for the babies was found to be higher than other groups but within the limit recommended by World Health Organization (WHO). The doses for the other two groups are below the recommended value
Nurul Ashikin Sidi Ahmad
2015-10-15T01:09:42Z
2017-09-19T04:40:06Z
http://eprints.utm.my/id/eprint/id/eprint/48243
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48243
2015-10-15T01:09:42Z
Numerical solution of non-isothermal compressible natural gases mixed with hydrogen in pipeline using method of lines
Nurul Asma Safiee
2015-10-15T01:09:42Z
2015-10-15T01:09:42Z
http://eprints.utm.my/id/eprint/id/eprint/48296
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48296
2015-10-15T01:09:42Z
The application of finite element method in burgers' equation
Nurul Akidah Adnan
2015-10-15T01:09:42Z
2015-10-15T01:09:42Z
http://eprints.utm.my/id/eprint/id/eprint/48301
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48301
2015-10-15T01:09:42Z
The use of white led for reflectance and surface structure study of ornamental leaf
Nurul Fatiha Qalbi Kamarudin
2015-10-15T01:09:41Z
2017-08-28T03:38:39Z
http://eprints.utm.my/id/eprint/id/eprint/48168
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48168
2015-10-15T01:09:41Z
Base heterogeneous catalytic transesterification of rice bran oil to biodiesel using calcium oxide nanostructured
Biodiesel or fatty acid ester is commonly produced by transesterification of vegetable oil or animal fat. Commercially, biodiesel was synthesized using homogeneous base catalysts such as NaOH and KOH. However, homogeneous base catalyst adsorped into the vegetable oil or animal fat. Thus, a large amount of water is required to clean the biodiesel and might lead to saponification or soap formation. As a result, this will lower the biodiesel quality and makes the biodiesel production becomes difficult, producing waste water, expensive and complicated. This research focused on the use of heterogeneous base catalyst, calcium oxide (CaO), an alkaline earth metal oxide that make the biodiesel easily separated, low cost and environmental friendly. The aim of this research is to investigate the potential of commercial calcium carbonate, CM-CaCO3 to be transformed to nanostructured CaO and used as a heterogeneous base catalyst for single step transesterification of rice bran oil to biodiesel. The CaO samples were prepared by calcination at 100°C to 700°C under vacuum at 10-3 mbar. The prepared CaO nanostructured was characterized by thermogravimetric analysis-differential thermal analysis (TGA-DTA), Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), nitrogen gas adsorption analysis (NA), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX). The basicity of the prepared CaO nanostructured was determined via back titration method. TGA-DTA result showed that the calcination temperature for CM-CaCO3 to form CaO must be higher than 600°C. This was supported by FTIR results which indicated the complete formation of CaO at 700°C. XRD showed that at this temperature, the rhombohedral CaCO3 and hexagonal Ca(OH)2 were totally disappeared leaving only crystalline cubic CaO. CaO obtained at 700°C (CaO-700) showed the highest BET surface area of 11.49 m2g-1. FESEM image showed the spherical particles coagulated to form agglomeration with nanoparticle size. The EDX further supported the formation of CaO and indicated to contain 53.56% of oxygen and 46.44% of calcium. It was found that CaO-700 has the highest basicity with 1.959 mmol/g. After optimization process, the prepared nanostructured CaO-700 was selected and applied for single step transesterification reaction of rice bran oil to produce biodiesel. The biodiesel produced was characterized using FTIR, NMR and GC-FID. The catalytic activity was further studied on the effect of time of reaction, percentage catalyst loading and a mechanism reaction was proposed. FTIR and NMR results further confirmed that biodiesel was successfully formed. In this study, the optimum reaction conditions to produce the highest biodiesel of 89% was at 60 minutes reaction time with 1.0% catalyst loading.
Nur Fatin Sulaiman
2015-10-15T01:09:41Z
2017-08-29T08:05:29Z
http://eprints.utm.my/id/eprint/id/eprint/48195
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48195
2015-10-15T01:09:41Z
Enhanced prim's algorithm for finding the hamiltonian cycle in a graph
The Travelling Salesman Problem (TSP) is known as one of the oldest combinatorial optimisation problem which solves the path problem in weighted graph. With the main objective to visiting all places (nodes) in a round trip that start and end in one specific place, TSP shared the same problem with a lot of applications in the world nowadays. In short, the goal of TSP is to find a Hamiltonian cycle. Hamiltonian cycle was introduced in 1800’s which is as old as the moment TSP captured the mind of the thinker. Lots of great and major discussions have been made till now and TSP has seen applications in the areas of logistics, genetics, manufacturing, telecommunications, neuroscience and many more. TSP has been intervening in many of the everyday experience by most people and not only for a salesman. Be it a usual errand around the house or the major project by the company or government, TSP has an innate connection in tour finding which lead the attention from various personnel. In another related graph problem, Prim’s Algorithm (PA) is widely used to compute the Minimum Spanning Tree (MST) of a graph. In this research, the two algorithms are being related by modifying the PA in order to work out the TSP which will find the Hamiltonian cycle of the graph. This new approach is called Enhanced Prim’s Algorithm (EPA) which solves the TSP for fast result
Nur Atiqah Dinon
2015-10-15T01:09:41Z
2017-10-29T08:55:25Z
http://eprints.utm.my/id/eprint/id/eprint/48209
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48209
2015-10-15T01:09:41Z
Finite difference method and finite volume method for solving navier-stokes equation in sea water movement
This project proposed the Navier-Stokes equation of sea water modeling. The mathematical modeling consists of momentum , heat and salinity equations. The three parameters influence on sea water movement are momentum, temperature and salinity. The discretization of Navier-Stokes equation is based on Finite Difference Method (FDM) and Finite Volume Method (FVM ). The numerical methods for solving FDM are JB and GS schemes. The results are computed by using Comsol Multiphysics Software (4.3a) and MATLAB 2011a. The numerical analyses are used to evaluate the comparisons of the FDM and FVM. The computational platform is Intel"' Core IM 2 Duo processor T7500 memory. The aspects of evaluation are number of iteration, time execution, maximum error and root square error and com putational complexity. The results show that FDM is alternative method in visualizing the movement of the sea water
Nur Syahida Mohamed
2015-10-15T01:09:41Z
2017-09-17T07:35:22Z
http://eprints.utm.my/id/eprint/id/eprint/48215
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48215
2015-10-15T01:09:41Z
Hydrophobic, structural and optical properties of zinc silica thin films
A fundamental study was conducted to investigate the hydrophobic properties, structural characteristics, surface morphology and topology, and luminescence properties of the zinc silica thin films due to various ZnO content. Hydrophobically zinc silica thin films, xZnO-(1-x)SiO2 with 0 < x < 20 wt%, have been prepared using a low temperature sol-gel process and dip coating technique. The hydrophobic properties were determined using contact angle measurement which gave the static water contact angle of 102 ± 1° for 20 wt% of ZnO. The structural characteristics were investigated using Infrared (IR) Spectroscopy in the range of 400 – 4000 cm-1. The peaks observed on the spectra showed the C-H, C-H3, Si-O-Si, Si-O-Zn and Zn-O bonding. The changes in morphology and topology were characterized by Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The surface roughness of the hydrophobic coatings showed a maximum value of 148.32 nm while the maximum size of the pores was found to be 6.47 µm. The optical absorption and photoluminescence properties were studied by means of UV-Visible optical absorption and Photoluminescence (PL) spectroscopy. All samples exhibited more than 90 % optical transmittance which indicated a higher transparency of the films. The emission spectra showed broad and sharp peaks of luminescence at 390, 420, 550 and 740 nm corresponding to the characteristic of Zn2+ due to transitions of 2S1/2?2D5/2, 2S1/2?2D3/2, 2D3/2?2P°3/2 and 2D5/2?2P°3/2, respectively. The thin films prepared in this work have shown to be promising materials for use in hydrophobic and water-resistant applications
Nur Aimi Syaqilah Aziz
2015-10-15T01:09:41Z
2015-10-15T01:09:41Z
http://eprints.utm.my/id/eprint/id/eprint/48273
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48273
2015-10-15T01:09:41Z
Prediction of total concentration for spherical and tear shape drops by using neural network
Norhusna Saharun
2015-10-15T01:09:41Z
2015-10-15T01:09:41Z
http://eprints.utm.my/id/eprint/id/eprint/48288
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48288
2015-10-15T01:09:41Z
Solving fractional diffusion equation using variational iteration method adomian decomposition method
Norizkiah Dzulkarnian
2015-10-15T01:09:40Z
2017-09-17T08:33:30Z
http://eprints.utm.my/id/eprint/id/eprint/48222
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48222
2015-10-15T01:09:40Z
Integral equation approach for computing green's function on unbounded simply connected region
This research is to compute the Green’s function on an unbounded simply connected region by conformal mapping and by solving an exterior Dirichlet problem. The exact Green’s function is found by using Riemann mapping and M bius transform. The Dirichlet problem is then solved using a uniquely solvable Fredholm integral equation on the boundary of the region. The kernel of this integral equation is the generalized Neumann kernel. The method for solving this integral equation is by using the Nystr?m method with the trapezoidal rule to discretize it into a system. The linear system is solved by the Gaussian elimination method. As an examination of the proposed method, several numerical examples for some various test regions are presented. These examples include a comparison between the numerical result and the exact solutions
Sheida Chahkandi Nezhad
2015-10-15T01:09:40Z
2017-09-18T07:21:58Z
http://eprints.utm.my/id/eprint/id/eprint/48226
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48226
2015-10-15T01:09:40Z
Irreducible representation of finite metacyclic group of nilpotency class two of order 16
Representation theory is a study of real realizations of the axiomatic systems of abstract algebra. It originated in the study of permutation groups, and algebras of matrices. Representation theory has important applications in physics and chemistry. This research focuses on finite metacyclic groups. The classification of finite metacyclic groups is divided into three types which are denoted as Type I, Type II and Type III. For any group, the number of possible representative sets of matrices is infinite, but they can all be reduced to a single fundamental set, called the irreducible representations of the group. Irreducible representation is actually the nucleus of a character table and is of great importance in chemistry. In this research, the irreducible representation of finite metacyclic groups of class two of order 16 are found using two methods, namely the Great Orthogonality Theorem Method and Burnside Method
Nizar Majeed Samin
2015-10-15T01:09:40Z
2017-09-20T06:35:37Z
http://eprints.utm.my/id/eprint/id/eprint/48247
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48247
2015-10-15T01:09:40Z
Optimization of fermentation conditions for protein production from effective microorganisms-fermented tiger prawn waste
Effective microorganisms or EM have been actively used for various reasons but mainly in the waste water treatment, as plant growth initiators and fertilizers. In this study, fermentations of local tiger prawn waste (Panaeus monodon) by EM were conducted. At the early screening stage, fermentations were carried out at various temperature conditions (25°C, 37°C and 60°C), using various starter inocula (EM/Lactic Acid Bacteria) and different sources of carbon (glucose/brown sugar (BS)). Their pH values, total titratable acidities and lactic acid bacterial growth were examined. The results showed that, all samples were successfully fermented after three days of fermentation process except for fermentation at 60°C. Temperature at 60°C had affected the fermentation considerably where the pH did not rapidly decrease. Various levels of carbon source and inoculum were also investigated during screening. The results showed that, acid production in the fermented sample were dependent on glucose concentration but less dependent on the inoculum level. Based on the screening results, fermentation of prawn waste was carried out using 10% EM inoculum, 10% BS and fermented at 37°C for three days and the produced protein liquor contained 46.67% (w/v), dry weight protein. In the optimization phase using central composite design (CCD), four factors were selected which are temperature (30°C – 50°C), incubation time (3 – 9 days), inoculum size (v/w) (1 - 3%) and carbohydrate level (w/w) (5 - 15%). The processing result was protein content. The results showed that, to obtain high protein content from fermented sample, the most significant factor was the interaction between temperature and % of sugar, and the least was the interaction between % of sugar and % inoculum. High protein content and lower pH value were obtained with the suggested conditions given by the software Design Expert® which are temperature of 30°C, 5% sugar, 1.05% inoculum and incubated for 3 days. After optimization studies, the liquor protein content was increased to 86.35%
Nor Masdiana Zulkeple
2015-10-15T01:09:39Z
2017-09-17T07:37:24Z
http://eprints.utm.my/id/eprint/id/eprint/48216
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48216
2015-10-15T01:09:39Z
Implementation of genetic algorithm in model identification of box-jenkins methodology
Mohd. Zulariffin Md. Maarof
2015-10-15T01:09:39Z
2015-10-15T01:09:39Z
http://eprints.utm.my/id/eprint/id/eprint/48299
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48299
2015-10-15T01:09:39Z
The effect of Yb3+ on corrosion of lead oxychloride tellurite glasses
Muhammad Abdullah Izat Mohd. Yassin
2015-10-15T01:09:38Z
2017-09-19T04:13:43Z
http://eprints.utm.my/id/eprint/id/eprint/48240
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48240
2015-10-15T01:09:38Z
Multivariate disaggregation of daily to hourly rainfall series
Tou Hin Lim
2015-10-15T01:09:38Z
2017-09-19T08:28:24Z
http://eprints.utm.my/id/eprint/id/eprint/48245
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48245
2015-10-15T01:09:38Z
Optimisation of moderator and neutron guide design for prompt gamma neutron activation analysis (PGNAA) using MCNP5 simulation
The performance of prompt gamma neutron activation analysis (PGNAA) setup depends on thermal neutron flux available at the sample. Neutrons available in most reactors consist of thermal, epithermal and fast neutrons with varying ratios. As such for PGNAA to be more efficient, the ratio of the total amount o f neutron to the epifast neutron must be high and this is being measured by the cadmium ratios. In order to increase the neutron flux, a moderator is used. In this study, combination of carbon, lead and silicon were modelled as a moderator to investigate the optimum thickness of moderator combination through a simulation technique. The moderator was tested with varying thickness of material assemblies and it was found that the combination of 1.48 cm carbon, 0.92 cm lead and 4.40 cm silicon gave the highest cadmium ratio. The Monte Carlo N-Particle transport code version 5 (MCNP5) and the exact dimension of the tangential beamport of Reactor Triga Puspati, Malaysian Nuclear Agency was used for the simulation purposes. The simulations then were run at seven locations along the tangential beamport in order to determine the position to place the moderator that yield the highest cadmium ratio. The location at 41.10 cm from the inner beamport exit produced 8.914 x 107 n cm'2 s'1 thermal neutron and 1.164 x 107 n cm'2 s '1 epi-fast neutron that yield 8.65 for the cadmium ratio. Consequently, this position could be suggested as the specific position to place the moderators for future PGNAA system at Reactor Triga Puspati. A one meter neutron guide has been proposed to be installed at the end of the moderator to transport the neutron with almost no neutron lost. The study shows that the proportion of thermal neutron lost was approximately 1.13 times
Mazni Mohamed Johan
2015-10-15T01:09:37Z
2017-08-28T04:10:12Z
http://eprints.utm.my/id/eprint/id/eprint/48172
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48172
2015-10-15T01:09:37Z
Broyden's and thomas' methods for identifying singular roots in nonlinear system
Nonlinear systems is one of the mathematical models that is commonly used in the engineering and science fields and it is quite complicated to determine the root especially when the problem is singular. This study is conducted in order to study the performance of Broyden’s and Thomas’ method, which are parts of Quasi-Newton method in solving singular nonlinear systems. By applying the algorithm of each methods, we conduct the calculation to achieve the approximate solutions. MATLAB software is used to compute and present the solutions. Some of useful test problems would describe the properties and usage of the methods. Hence, both methods that have been considered in this study give well approximate solution but Thomas’ method gives better results than Broyden’s method.
Ikka Afiqah Amir
2015-10-15T01:09:37Z
2015-10-15T01:09:37Z
http://eprints.utm.my/id/eprint/id/eprint/48281
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48281
2015-10-15T01:09:37Z
Root counting in product homotopy method
Hazrina Tajudin
2015-10-15T01:09:36Z
2015-10-15T01:09:36Z
http://eprints.utm.my/id/eprint/id/eprint/48157
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48157
2015-10-15T01:09:36Z
An optimal control of water pollution in river
Chew, Kim Fie
2015-10-15T01:09:34Z
2017-08-21T07:04:48Z
http://eprints.utm.my/id/eprint/id/eprint/48177
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48177
2015-10-15T01:09:34Z
Combine holts winter and support vector machines in forecasting time serie
This study proposes on a combine methodology that exploits the Holts- Winter (HW) model and the Support Vector Machines (SVM) model in forecasting time series. Problems of forecasting using time series data have been and still being addressed at every sphere of research using different approaches. The performance of the forecast was compared among the three models, the HW model, the SVM model and the combine model (HW and SVM). Four different data sets namely, airline passengers’ data, machinery industry production data, clothing industry data and sugar production data were considered in the study. The statistical measures such as mean squared error (MSE), mean average error (MAE) and correlation coefficient, R, were used to evaluate the performance of the propose model. The result of this study indicated that the combine model shows an improvement of 149.3% over HW model and 35.9% improvement over the SVM model for the airline passengers’ data. The result of the machinery industry presented that the combine model shows an improvement of 93.3% over HW model and 42.8% improvement over the SVM model. In the case of the clothing industry the result shows the combine model gives an improvement of 61.6% over HW model and 12.0% improvement over SVM model. Lastly, with respect to the sugar production, the result shows that the combine model indicated an improvement of 34.4% over HW model and 25.1% improvement over SVM model. Therefore the results of the experiments suggest that the proposed combine model is more reliable in time series when compared with the individual models
Mohammed Salisu Alfa
2015-10-15T01:09:34Z
2017-09-13T06:49:39Z
http://eprints.utm.my/id/eprint/id/eprint/48203
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48203
2015-10-15T01:09:34Z
Exact solutions of unsteady free convection flow past an oscillating plate with newtonian heating
The motion of a viscous fluid caused by the oscillations of a vertical plate is important in many applied problems such as acoustic streaming around an oscillating body and an unsteady boundary layer with fluctuations. In boundary layer, free convection flow is a motion that results from the interaction of gravity with density differences within a fluid. These differences occur due to temperature or concentration gradients or due to their composition. The situation where the heat be transported to the convective fluid via a bounding surface having finite heat capacity is known as Newtonian heating (or conjugate convective flows). This configuration occurs in convection flows set up when the bounding surfaces absorb heat by solar radiation. In this thesis, the unsteady free convection flow of an incompressible viscous fluid past an oscillating vertical plate with Newtonian heating is studied. The free convection flow with either heat or heat and mass transfer with radiation effect is considered. The problem of magnetohydrodynamic free convection flow in a porous medium is also studied. Appropriate non-dimensional variables are used to reduce the dimensional governing equations along with imposed initial and boundary conditions into dimensionless forms. The exact solutions for velocity, temperature and concentration are obtained using the Laplace transform technique. The corresponding expressions for skin friction, Nusselt number and Sherwood number are also calculated. The graphical results are displayed to illustrate the influence of various embedded parameters such as Newtonian heating parameter, radiation parameter, Grashof number and phase angle. The results obtained show that the effect of Newtonian heating parameter increases the Nusselt number but reduces the skin friction. However, the Nusselt number is decreased when the radiation parameter is increased. Also, the skin friction is decreased when the radiation parameter, phase angle and Grashof number are increased
Abid Hussanan
2015-10-15T01:09:34Z
2017-09-17T08:52:49Z
http://eprints.utm.my/id/eprint/id/eprint/48224
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48224
2015-10-15T01:09:34Z
Intraguild predation model (IGP) with disease
Intraguild Predation (IGP) classified as killing and eating among potential competitors. Intraguild Predation is ubiquitous interaction, differing from competition or predation. The purpose of this study is to investigate the effects of disease on the susceptible prey. Here we analyze the LotkaVolterra competition model and Intraguild Predation model. In order to keep the model simple, an assumption has been made that is no any migration or immigration for the intraguild predator and intraguild prey. We also analyze using the SI model, the simplest epidemiological model. We analyzed the entire model by finding the stability of the equilibrium points by using Routh – Hurwitz criteria. Numerical example is used to show the stability of the equilibrium point by using the MAPLE software
Aimi Nuraida Ali Hassan
2015-10-15T01:09:34Z
2015-10-15T01:09:34Z
http://eprints.utm.my/id/eprint/id/eprint/48290
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/48290
2015-10-15T01:09:34Z
Structural and luminescence properties of zinc antimony borophosphate glass doped with rare-earth ions
Aliff Rohaizad
2015-10-05T03:41:16Z
2017-07-17T06:48:31Z
http://eprints.utm.my/id/eprint/id/eprint/47944
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47944
2015-10-05T03:41:16Z
Integral equation approach for computing green's function on unbounded simply connected region
This research is to compute the Green’s function on an unbounded simply connected region by conformal mapping and by solving an exterior Dirichlet problem. The exact Green’s function is found by using Riemann mapping and M bius transform. The Dirichlet problem is then solved using a uniquely solvable Fredholm integral equation on the boundary of the region. The kernel of this integral equation is the generalized Neumann kernel. The method for solving this integral equation is by using the Nystr?m method with the trapezoidal rule to discretize it into a system. The linear system is solved by the Gaussian elimination method. As an examination of the proposed method, several numerical examples for some various test regions are presented. These examples include a comparison between the numerical result and the exact solutions.
Sheida Chahkandi Nezhad
2015-10-01T01:58:20Z
2017-07-17T07:28:16Z
http://eprints.utm.my/id/eprint/id/eprint/47947
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47947
2015-10-01T01:58:20Z
Characterization of lithium-magnesium-tellurite doped with erbium and neodymium glass
Tellurite glass based on (78-x)TeO2-10Li2O-10MgO-2Nd2O3-xEr2O3, (where x = 0.4 to 2.0 mol %) has successfully been prepared by melt-quenching technique. The colour of glass is found to vary from light violet to dark violet as the Er2O3 content is increased. No definite peaks are found from the X-ray diffraction pattern, which shows that the glass is amorphous in nature. It also found that the densities and the molar volume of the glass increase as the Er2O3 content is increased. The glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm) and the temperature difference (Tc-Tg) are determined by means of Differential Thermal Analysis (DTA). It is found that the Tc, Tg and Tm are in the range of (419-430) oC, (300-345) oC and (885-890) oC respectively. Meanwhile, the vibrational study is conducted using the Infrared spectroscopy in the range of (4000-400) cm–1. Two major absorption peaks are observed around (1600-3600) cm–1, and (900-1200) cm–1 which are due to the stretching mode vibration of OH peak and Te-OH peak respectively. The optical absorption edge is studied using UV-Vis spectroscopy. The result shows that the optical band gap (Eopt) and Urbach Energy (?E) are in the range of (3.038-3.130) eV and (0.334-0.321) eV respectively, depending on the Er2O3 concentration. The refractive index is evaluated using the Sellmeier’s equation and it is found that the value in the visible region is in the range of 1.724-1.781 depending on the Er2O3 content. The emission spectrum is recorded using the photoluminescence spectrometer excited at 582 nm at room temperature. The result shows that the emission spectrum of Er3+ and Nd3+ consist of five emission bands at ~457 nm, ~495 nm, ~556 nm, ~611 nm, and ~ 665 nm which can be assigned as a transition of 4F7/2-4F15/2, 4S3/2-4F15/2, 4G11/2 - 4I9/2, 4G11/2 - 4I15/2 and 4G7/2 - 4I13/2 respectively.
Syaridatul Akmar Roslan
2015-10-01T01:55:37Z
2017-07-17T04:24:08Z
http://eprints.utm.my/id/eprint/id/eprint/47943
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47943
2015-10-01T01:55:37Z
Discrete adomian decomposition method for solving fredholm integral equations of the second kind
The nonlinear Fredholm integral equation (FIE) represents a large amount of nonlinear phenomena that usually produces a considerable amount of difficulties. This dissertation will display some methods used for solving this problem, such as an Adomian Decomposition Method (ADM) which is based on decomposing the solution to infinite series and numerical implementation of ADM for the special case when the kernel is separable. In addition, it discusses the process of applying the Discrete Adomian Decomposition Method (DADM) which gives the numerical solution at the nodes using quadrature rules like Simpsons rule and trapezoidal rule. The comparison of DADM with of both rules with the exact solution also are given. Furthermore the results from DADM, Triangles orthogonal functions (Tfs) and Rationalized Haar function (RHf) for two dimensional linear and nonlinear FIE of the second kind respectively are compared with exact solution. Hence the results obtained show equivalent accuracy when linear FIE of the second kind for two dimension were solved by DADM with Simpson’s rule and by Tfs. Whereas the results show of DADM with Simpson’s rule is more accurate than RHf to solve nonlinear FIE of the second kind for 2-D.
Salar Hameed Mohammed
2015-10-01T01:55:00Z
2017-07-17T08:09:53Z
http://eprints.utm.my/id/eprint/id/eprint/47942
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47942
2015-10-01T01:55:00Z
Prediction of total concentration for spherical and tear shape drops by using neural network
In this study, the development of an alternative approach based on the Artificial Intelligent technique called Artificial Neural Network (ANN) was carried out. This report presents a new application of ANN techniques to the modeling of prediction total concentration of drops in the Rotating Disc Contactor Column (RDC). The ANN was trained with the simulated data based on spherical and tear-shaped drops, which consider ten classes volume of drops. The comparison result between Neural Network output and Mathematical Model output is presented. With 4 hidden nodes, the Neural Network models are able to generate the smallest MSE for each ten classes volume of drops. Then the neural network model is then being applied to the combination for all shape drops, which are spherical and tear shape drops as the inputs. The Neural Network models are able to predict 400 simulated data for combination spherical and tear shape drops with MSE error value 68482.6?E. The results with the smallest MSE presented in this paper shows that the Neural Network Model works successfully in prediction total concentration of multiple shape drops in ten classes volumes.
Norhusna Saharun
2015-10-01T01:53:40Z
2017-07-17T07:14:29Z
http://eprints.utm.my/id/eprint/id/eprint/47940
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47940
2015-10-01T01:53:40Z
Application of multi-criteria decision making method in seletion of academic staff at Faculty of Science, Universiti Teknologi Malaysia
The selection of academic staff is important process for the university because the decision will affect the quality and the success of the university. Academic staff is the professional career as they are person who have the high skills in their respective fields. It is not easy for the selection committee to select appropriate personnel as they always faces up to uncertainty decision making process. Two Multiple Criteria Decision Making (MCDM) method namely Analytic Hierarchy Process (AHP) and Elimination and Choice Translating Reality I (ELECTRE I) are adopted to enable the decision makers to make effective decision in selecting academic staff. Both methods helps permit pair-wise comparison judgments in expressing the relative priority for criteria and alternatives that is translated from qualitative to quantitative data by considering the criteria that influence decision made. This study has applied six main criteria and fifteen sub-criteria for selecting the best one amongst seven candidates for the academic staff position in the Faculty of Science, UTM. The selection criteria of Academic, General Attitudes, Interpersonal Skill, Experience, Extracurricular Activities, and Referees Report that used in this study are determined based on some literature reviews and knowledge acquisition by interview Deputy Registrar from Registrars‘ Office and Assistant Registrar from Faculty of Science, UTM. By applying both methods, Candidate 7 should be selected as academic staff since she possesses the first rank of the generated candidate profile. Expert Choice 11.0 and Microsoft Excel 2007 are used to assist in accomplishing the calculation involved. As a suggestion for future work, other researches could apply the other of MCDM method in selecting academic staff.
Nurul Duratulain Ramlan
2015-10-01T01:53:02Z
2017-07-13T04:10:57Z
http://eprints.utm.my/id/eprint/id/eprint/47939
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47939
2015-10-01T01:53:02Z
Solving fractional diffusion equation using variational iteration method and adomian decomposition method
Fractional calculus has been used in many areas of sciences and technologies. This is the consequences of the elementary calculus. The order of the derivative in elementary calculus is integer, n. The nth derivative was changed to a for fractional calculus, where a is a fraction number or complex number. Fractional diffusion equation is one of the examples of fractional derivative equation. This study will focus on the solving fractional diffusion equation using variational iteration method and Adomian decomposition method to obtain an approximate solution to the fractional differential equation. Graphical output may explain further the results obtained. In certain problems the use of fractional differential equation gives more accurate representation rather than using elementary differential equation. Adomian decomposition method is easier in solving fractional diffusion equation since there is no nonlinear term in the equation. However, variational iteration method is more suitable to be applied in solving fractional derivative equation that consists of nonlinear term.
Norizkiah Dzulkarnain
2015-10-01T01:52:27Z
2017-07-17T08:42:11Z
http://eprints.utm.my/id/eprint/id/eprint/47938
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47938
2015-10-01T01:52:27Z
Grammar systems in simple splicing
Splicing systems was first introduced by Head in 1987 as a mathematical model of the generative formalism that initiates the connection between formal language theory and the study of deoxyribonucleic acid (DNA). The mathematical modeling of splicing was developed by involving the activities of restriction enzymes and ligases on a set of DNA molecules. The language resulted from the splicing systems is called the splicing language. The splicing languages are then formalized and investigated by using concepts in formal language theory. Among the different types of splicing systems is the simple splicing system. In this research, some molecular examples on the reduction process of splicing systems into simple splicing systems by using the concept of solid codes are presented. This research focuses on simple splicing systems and its relation with grammar systems where grammar is one of the basic concepts in formal language theory. Among the grammar systems presented in this research are the four types of simple splicing grammar systems (SSGS), pattern grammar systems and pure pattern grammar systems. Then, SSGS is further applied in the test tube system, known as the simple test tube systems. The languages resulted from the various types of SSGS in simple test tube systems are then being analyzed and compared.
Nurul 'Alyaa' Shukri
2015-10-01T01:51:47Z
2017-06-20T08:38:52Z
http://eprints.utm.my/id/eprint/id/eprint/47937
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47937
2015-10-01T01:51:47Z
Effect of photon irradiation on the thermoluminescence response of optical fibres
Studies on silica glass (SiO2) optical fibre as thermoluminescent materials for medical radiation dosimetry have been conducted by several research groups. This study focuses on the thermoluminescence (TL) response, linearity, sensitivity, dose response, fading, reproducibility and minimum detectable dose of 12 optical fibres sample namely Ge (A) Batch 1, 2 and 3, Ge (B), Multi Photonic Crystal Fibre (MPCF, 220 µm), Multi Photonic Crystal Fibre (MPCF, 2 mm), photonic crystal fibres (PCF), Dummy Flat Fibre (DFF), Flat fiber, Photosensitive Flat Fibre (PFF), Erbium (Er) and Aluminium/ Thulium (Al + Tm) doped optical fibre. A comparison was performed with TLD-100 (chips) to obtain the best TL response among the samples. Irradiation were performed with 6 and 10 MV photons covering the dose range of 1 Gy to 4 Gy by using linear accelerator machine Elekta SynergyTM at Pantai Hospital, Kuala Lumpur and Varian Model 2100C linear accelerator at University Malaya Medical Centre (UMMC). The comparisons of TL response with different model linear accelerators involved in this research were also performed. The results show that the highest sensitivity was obtained by using TLD-100, followed by PFF, Flat, Ge (A) Batch 1, MPCF (2 mm), Ge (A) Batch 3, Ge (A) Batch 2, DFF, Al+Tm, Ge (B), Er, MPCF (220 µm) and PCF. The fading of 5 optical fibres Ge (A) Batch 1, PFF, Er, Flat Fibre and PCF were determined and the loss of the TL signal for these TL materials were 10%, 29%, 30%, 30% and 43%, respectively. The dopant concentrations of Ge (A) Batch 1, Ge (B) and Er were found to be in the range of 0.03-0.72 mol % while the Zeff was in the range of 11.9-17.1. These TL materials have great potential to be introduced as new radiation dosimeters.
Nurul Ain Mohamad Sharif
2015-10-01T01:51:10Z
2017-06-21T07:38:44Z
http://eprints.utm.my/id/eprint/id/eprint/47936
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47936
2015-10-01T01:51:10Z
Mathematical modelling of river pollution by determining the level of dissolved oxygen and pollutant concentration
A mathematical model of a coupled advection-diffusion equation of river pollution problem is investigated. The concentration of pollutants and dissolved oxygen were obtained from the model with and without dispersion coefficient for steady and unsteady states. The unsteady models were solved analytically using the method of Laplace transform for linear case and numerically by finite difference method for nonlinear case. The calculations also involved the absence and presence of half saturated oxygen with Michaelis-Menten term. A parameter analysis was carried out in order to observe the effects of each parameter involved in this model with respect to pollutant and dissolved oxygen concentration. The values of certain parameters such as velocity, cross section area, dispersion of pollutant and dissolved oxygen were obtained from the observational data in other relevant studies. The research methodology which is being implemented in this work was generic and can be used with little modification for other rivers.The mathematical model and its validated solution for Skudai River act as a decision support on the restriction and regulation to be imposed for monitoring the river pollution.
Nurra Mahadi
2015-10-01T01:50:35Z
2017-09-11T03:16:14Z
http://eprints.utm.my/id/eprint/id/eprint/47935
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47935
2015-10-01T01:50:35Z
Enhanced prim's algorithm for finding the hamiltonian cycle in a graph
The Travelling Salesman Problem (TSP) is known as one of the oldest combinatorial optimisation problem which solves the path problem in weighted graph. With the main objective to visiting all places (nodes) in a round trip that start and end in one specific place, TSP shared the same problem with a lot of applications in the world nowadays. In short, the goal of TSP is to find a Hamiltonian cycle. Hamiltonian cycle was introduced in 1800’s which is as old as the moment TSP captured the mind of the thinker. Lots of great and major discussions have been made till now and TSP has seen applications in the areas of logistics, genetics, manufacturing, telecommunications, neuroscience and many more. TSP has been intervening in many of the everyday experience by most people and not only for a salesman. Be it a usual errand around the house or the major project by the company or government, TSP has an innate connection in tour finding which lead the attention from various personnel. In another related graph problem, Prim’s Algorithm (PA) is widely used to compute the Minimum Spanning Tree (MST) of a graph. In this research, the two algorithms are being related by modifying the PA in order to work out the TSP which will find the Hamiltonian cycle of the graph. This new approach is called Enhanced Prim’s Algorithm (EPA) which solves the TSP for fast result.
Nur Atiqah Dinon
2015-10-01T01:49:59Z
2017-07-11T01:23:43Z
http://eprints.utm.my/id/eprint/id/eprint/47934
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47934
2015-10-01T01:49:59Z
The application of finite element method in burgers’ equation
The main objective of this project is to provide the explanation of the application of Finite Element method in 1- dimensional Burgers’ equation. Burgers’ equation captures very important phenomena surrounding world. Its can be categorized as a parabolic, elliptic and hyperbolic partial differential equation. For this reason, Burgers equation is often used as a case study for testing and comparing computational technique. The 1- dimension Burgers’ equation is investigated and their results are compared with analytical solution of the problem. To solve the problem in finite element method, few concept are introduced such that calculus of variation, weight function, and weak formulation. A brief explaination of the calculation using Finite Element Method (FEM) is given. In this research, the Finite Element method algorithm is written in Matlab and Maple programme. Based on the numerical results, we can see from the behaviour of the graph , the solution is approching some limit as we increased the number of Reynolds. The error between numerical and analytical result becomes larger. We cay say that , FEM is a unique and useful technique and it is being extended to solve many problem in engineering and science area.
Nurul Akidah Adnan
2015-10-01T01:49:22Z
2017-07-18T06:44:31Z
http://eprints.utm.my/id/eprint/id/eprint/47933
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47933
2015-10-01T01:49:22Z
Hydrophobic, structural and optical properties of zinc silica thin films
A fundamental study was conducted to investigate the hydrophobic properties, structural characteristics, surface morphology and topology, and luminescence properties of the zinc silica thin films due to various ZnO content. Hydrophobically zinc silica thin films, xZnO-(1-x)SiO2 with 0 < x < 20 wt%, have been prepared using a low temperature sol-gel process and dip coating technique. The hydrophobic properties were determined using contact angle measurement which gave the static water contact angle of 102 ± 1° for 20 wt% of ZnO. The structural characteristics were investigated using Infrared (IR) Spectroscopy in the range of 400 – 4000 cm-1. The peaks observed on the spectra showed the C-H, C-H3, Si-O-Si, Si-O-Zn and Zn-O bonding. The changes in morphology and topology were characterized by Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The surface roughness of the hydrophobic coatings showed a maximum value of 148.32 nm while the maximum size of the pores was found to be 6.47 µm. The optical absorption and photoluminescence properties were studied by means of UV-Visible optical absorption and Photoluminescence (PL) spectroscopy. All samples exhibited more than 90 % optical transmittance which indicated a higher transparency of the films. The emission spectra showed broad and sharp peaks of luminescence at 390, 420, 550 and 740 nm corresponding to the characteristic of Zn2+ due to transitions of 2S1/2?2D5/2, 2S1/2?2D3/2, 2D3/2?2P°3/2 and 2D5/2?2P°3/2, respectively. The thin films prepared in this work have shown to be promising materials for use in hydrophobic and water-resistant applications.
Nur Aimi Syaqilah Aziz
2015-10-01T00:27:01Z
2017-07-04T00:38:03Z
http://eprints.utm.my/id/eprint/id/eprint/47932
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47932
2015-10-01T00:27:01Z
Measurement of radon-222 and radium-226 in well water of Kelantan
The Environmental Protection Agency (EPA) of USA sets the Maximum Contamination Level (MCL) for 222Rn in drinking water to be 11.1000 Bq/l and for 226Ra to be 0.1100 Bq/l. This study was conducted to determine the levels of 222Rn and 226Ra in private well water in the state of Kelantan. A total of 25 samples of well water were collected from various districts in the state. The levels of 222Rn and 226Ra dissolved in well water were measured using the liquid scintillation counting technique. 222Rn activity concentrations were found within the range of 0.0491 to 4.3127 Bq/l for both unfiltered and filtered samples. Meanwhile, activity concentration of 226Ra measured is between 0.0278 to 1.9670 Bq/l for both unfiltered and filtered samples, exceeding the MCL value. The annual effective doses due to the intake of natural radionuclide from well water for three different age groups were estimated based on the amount of water consumed. The average annual effective dose of 226Ra calculated for babies in the range of 0.12 to 1.79 µSv/y. The average annual effective dose of 226Ra for children was in the range of 0.11 to 0.34 µSv/y while, for the adults, it was in the range of 0.11 to 0.33 µSv/y for 226Ra. The annual effective dose intake for the babies was found to be higher than other groups but within the limit recommended by World Health Organization (WHO). The doses for the other two groups are below the recommended value.
Nurul Ashikin Sidi Ahmad
2015-10-01T00:26:20Z
2017-09-17T01:43:56Z
http://eprints.utm.my/id/eprint/id/eprint/47931
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47931
2015-10-01T00:26:20Z
Numerical solution of non-isothermal compressible natural gases mixed with hydrogen in pipeline using method of lines
The effect of hydrogen injection into natural gas pipelines is investigated in particular the pressure and temperature conditions, real gas effects, Joule–Thomson effect, linepack and energy consumption of the compressor station. Real gas effects are a form of compressibility factor calculated using a particular predictive group contribution method. It is being incorporated with the conventional mixing rule, which in turn being used as a parameter in the non-isothermal transient flow model. A non-isothermal gas flow is a two-way interaction between gas flow and heat transfer. Although many other engineering cases isothermal model is usually adopted in situations over a long pipeline system, the non-isothermal case is considered here. When a gas is subjected to a temperature change, properties such as density and viscosity, change accordingly. In some situations, these changes are large enough to have a substantial influence on the flow characteristics. Because the gas transports heat, the temperature is in turn affected by changes in the flow characteristics. While it is convenient to treat that flow in pipeline is steady because it is easier to solve and under many conditions produces adequate results, gas pipeline system does not usually operate under steady condition. As such, an assumption that the gas flow in pipeline is in an unsteady condition is made. The gas flow is described by a set of partial differential equations (PDE) resulting from the conservation of mass, momentum and energy. The PDE are solved using the Method of Lines (MOL) and which in turn resulted in ordinary differential equations (ODE). The ODE is solved using the fourth order Runge Kutta Method. The Yamal-Europe gas pipeline on Polish territory is selected as case study, where results for the thermodynamic properties of mixed hydrogen-natural gas significantly differed from those of natural gas. The presence of hydrogen in natural gas mixture impacted the pressure and temperature gradient in the pipeline as hydrogen injection into the pipeline reduced the molecular weight of the gas mixture. Besides that, Joule-Thomson effect dominates the temperature profile and even causes a temperature drop below the soil temperature.
Nurul Asma Safiee
2015-10-01T00:25:20Z
2017-06-22T03:09:49Z
http://eprints.utm.my/id/eprint/id/eprint/47930
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47930
2015-10-01T00:25:20Z
Symmetric and asymmetric garch models for forecasting the prices of gold
Gold prices forecasts are of interest to many people. Gold prices however, change rapidly from period to period. In short, they are not constant. The change is not only in the mean, but also in the variability of the gold prices series. Daily gold prices per ounce, from January 3, 2000 to December 31, 2010 is used in this study with the Schwarz Information Criterion (SIC), Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE) as the forecasting accuracy measures. For the purpose of this study, gold prices from ten major consumer countries are examined. The currencies are American dollar, Australian dollar, Canadian dollar, Swiss franc, Chinese renmimbi, Egyptian pound, Euro, Japanese yen, Turkish lira and South African rand. This study considers five models from the GARCH-family namely the Generalized Autoregressive Conditional Heteroscedasticity (GARCH (p, q)), GARCH-M, Power of GARCH (PGARCH), Threshold GARCH (TGARCH) and Exponential GARCH (EGARCH). These models are analyzed by using the E-Views 6.0 software. Several combinations of p and q values are considered to develop several GARCH (p, q) models. Using the maximum likelihood method to estimate the coefficients in the models, followed by model validation and model selection criteria, it is concluded that EGARCH (1, 1) and TGARCH (1, 1) are the best models for eight of the currencies understudied.
Yean Ping Pung
2015-10-01T00:24:42Z
2017-07-17T07:53:22Z
http://eprints.utm.my/id/eprint/id/eprint/47929
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47929
2015-10-01T00:24:42Z
Irreducible representation of finite metacyclic group of nilpotency class two of order 16
Representation theory is a study of real realizations of the axiomatic systems of abstract algebra. It originated in the study of permutation groups, and algebras of matrices. Representation theory has important applications in physics and chemistry. This research focuses on finite metacyclic groups. The classification of finite metacyclic groups is divided into three types which are denoted as Type I, Type II and Type III. For any group, the number of possible representative sets of matrices is infinite, but they can all be reduced to a single fundamental set, called the irreducible representations of the group. Irreducible representation is actually the nucleus of a character table and is of great importance in chemistry. In this research, the irreducible representation of finite metacyclic groups of class two of order 16 are found using two methods, namely the Great Orthogonality Theorem Method and Burnside Method.
Nizar Majeed Samin
2015-10-01T00:24:03Z
2017-07-11T03:59:21Z
http://eprints.utm.my/id/eprint/id/eprint/47928
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47928
2015-10-01T00:24:03Z
Model peralihan jisim serentak bagi titisan-titisan yang pelbagai saiz
Liquid-liquid extraction is one of the important transfer operations in chemical engineering. In the design of extraction equipment, basic understanding of the mechanism of mass transfer between disperse phase and the continuous phase is very important. Typically, this problem is solved by means of measuring the mass transfer rate obtained from rotating disc extraction column (RDC) that was predicted by the model of simultaneous mass transfer. Because the mass transfer rate depends on several factors which sometimes can not be measured accurately, as the form of drops, drop size and the differences that occur in the RDC column. This study focuses on the modeling of the diffusion problem in different sizes of drop size in a stage of RDC column using the concept of diffusion in spherical drop with the assumption that the diffusion process from the continuous phase to the disperse phase occur simultaneously. Next, the simulation process for the mass transfer process of 10 drops with various sizes in a stage is done using simultaneous mass transfer model.
Syafikah Ayob
2015-10-01T00:22:45Z
2017-07-06T04:19:50Z
http://eprints.utm.my/id/eprint/id/eprint/47926
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47926
2015-10-01T00:22:45Z
Structural and luminescence properties of zinc antimony borophosphate glass doped with rare-earth ions
A quaternary system of borophosphate glasses formulated with zinc and antimony were prepared in three series, namely series A, series B and series C. All the samples in each series were prepared using melt quenching technique followed by annealing at 350oC for 1 hour. The best composition in Series A [10P2O5–40B2O3–(50-x)Sb2O3–(x)ZnO] (10 = x = 50) in terms of stability and transparency, was selected for preparation of Series B [10P2O5–40B2O3–40Sb2O3–10ZnO–1 RE] (RE=Sm3+/Eu3+/Er3+/Nd3+), in order to study the effect of the different dopand ions to the molecular structure and luminescent properties of the glass system. Series C of [10P2O5–40B2O3–40Sb2O3–10ZnO–(x)Sm2O3] (0.5 = x = 2.0) was prepared to study the effect of samarium concentration on the luminescence properties. The XRD results showed that the crystalline phase of the glass changed with different amount of zinc and antimony substitution. Crystalline phase was observed for sample containing more than 30 mol % of zinc oxide. Result of IR spectroscopy indicated that ZnO affected the basic coupling units of P-O bond and Sb3+ ions entered the glass system by breaking up the B-O-B bonds. The modification of zinc antimony borophosphate glasses with rare earth was studied and showed that the presence of rare earth ion in the glass system did not change the structural features. Among various rare earth, Eu3+ and Sm3+ showed the strongest luminescence intensity. The luminescence intensity of Sm doped glass changed in no specific pattern when the concentration, x increased from 0.5 to 2.0 mol %. The samarium doped glass showed intense luminescence with a very sharp peak dominated by the 4G5/2 ?6H7/2 transition at 590 nm.
Aliff Rohaizad
2015-10-01T00:19:50Z
2017-07-06T04:26:20Z
http://eprints.utm.my/id/eprint/id/eprint/47924
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47924
2015-10-01T00:19:50Z
Root counting in product homotopy method
Product Homotopy method is used to solve dense multivariate polynomial systems for finding all isolated solutions (real or complex). There are two stages in the computation of Homotopy method which are root counting and root finding. This study focuses on root counting which involves the computation of multi-homogeneous Bézout number (MHBN). This value determines the number of solution path in the second stage. Homogenization of partition each gives its own MHBN. Therefore, it is crucial to have minimum MHBN. The computation of minimum MHBN using local search method, fission and assembly method and genetic algorithm had become intractable when the system size gets larger. Hence, this study applied recent heuristic method, Tabu Search. Other than that, the computation of estimating MHBN is of exponential time. For large size system, the usage of row expansion with memory becomes impossible, hence, this study focus on implementing General Random Path algorithm (GRPA). This study implements Tabu search method and GRPA into several systems of different sizes. Tabu search is effective since the global minimum is obtained instead of the local minimum. Other than that, the number of visited partition is much smaller compared with the previous method. Although GRPA gives estimated value, it helps for large size system. We implement two accuracy level in the computation and in the result, the N=1000 gives more accurate result. Hence, GRPA is important when it comes to solve estimated MHBN for large size system.
Hazrina Tajudin
2015-10-01T00:19:12Z
2017-07-11T01:47:46Z
http://eprints.utm.my/id/eprint/id/eprint/47923
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47923
2015-10-01T00:19:12Z
First-principles study of structural, electronic and optical properties of AlN, GaN, InN and BN compounds
Nitride semiconductor compounds have been occupying the center of scientific attention due to their extraordinary physical properties for many years. In this study, the structural, electronic and optical properties of aluminium nitride (AlN), gallium nitride (GaN), indium nitride (InN) and boron nitride (BN) have been investigated by using full potential linear augmented plane waves plus local orbital’s method as embodied in WIEN2k code within the framework of density functional theory. These properties of the above-mentioned semiconductor compounds within two phases (wurtzite and zinc blende) have been calculated by the local density approximation, generalized gradient approximations and the recently developed modified Becke and Johnson exchange potential plus local-density approximation methods. In this study, the calculations show that the present results of the above said compounds for the lattice constant, bulk modulus and its pressure derivative are consistent with the experimental results. The energy band gaps obtained from modified Becke and Johnson exchange potential plus local-density method are in very close agreement with the experimental results. Moreover, modified Becke and Johnson exchange potential plus local-density approximation method shows improvement over the local density approximation and generalized gradient approximation. As for optical properties, it was found that the local density approximation and generalized gradient approximation results of static dielectric constant, static refractive index and reflectivity are in agreement with the experimental values.
Mowafaq Mohammad Kethyan Al-Sardia
2015-10-01T00:17:54Z
2017-07-06T01:49:47Z
http://eprints.utm.my/id/eprint/id/eprint/47921
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47921
2015-10-01T00:17:54Z
Implementation of genetic algorithm in model identification of box-jenkins methodology
During the past several decades, a considerable amount of studies have been carried out on time series and in particular the Box-Jenkins (BJ) method. As with all techniques of statistical analysis, the conclusions of time series analysis are critically dependent on the assumptions underlying the analysis and BJ is a commonly used forecasting method that can yield highly accurate forecasts for certain types of data. Genetic Algorithm (GA) is a heuristic method of optimization. This study presents the study on developing an extrapolative BJ model with the use of GA method to produce forecasting models using time series data. BJ method has a cycle of four phases, the data transformation phase for model identification, parameter estimation, model diagnostic checking or validation, and finally producing the forecast. Although many researchers and practitioners have concentrated in the parameter estimation part of BJ model, the most crucial stage in building the model is in the data transformation and model identification where any false identification will lead to assuming a wrong model and will increase in the cost of reidentification. Hence, using GA a subset of artificial intelligence methods was introduced into the process of BJ to solve the problem in the model identification and parameter estimation phase. The data used in this study are the monthly data of international tourists arrival into Malaysia from 1990 to 2011. This is a case study in the implementation of GA-BJ model. The result from this study may be divided into two main parts, namely the result for the in-sample data (fitted model) and outsample data (forecast model). The analysis shows that the out-sample values using GA-BJ model gives better forecast accuracy than the out-sample values for BJ model. This shows that the combination of BJ and GA methods gives a more accurate model than using a single method for forecasting. This study concludes that GA method can be an alternative way in identifying the right order of component in BJ model.
Mohd. Zulariffin Md. Maarof
2015-10-01T00:14:44Z
2017-09-11T03:03:13Z
http://eprints.utm.my/id/eprint/id/eprint/47918
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47918
2015-10-01T00:14:44Z
Mathematical modeling of water pollution in river
This project proposed a steady one-dimensional advection-dispersion-reaction equation to calculate the chemical oxygen demand (COD) concentration in a river. (COD) refers to the amount of oxygen required to oxidize the organic compounds in a water sample to carbon dioxide and water[1]. It is used for monitoring and control of discharges, and for assessing water treatment performance[2]. The equation is converted to second order linear ordinary differential equation and solved by using finite difference method (FDM). The method involving finite differences for solving boundary-value problems replace each of the derivatives in the differential equation with an appropriate difference-quotient approximation. The derivatives are approximated by using forward difference, backward difference and central difference. The resulting system of equations is expressed in the tridiagonal N x N matrix form which can be solved by Thomas Algorithm. From the result, a total of 1.0161 mg/L COD concentrations is reduced with the least treatment cost of euro 663. In addition, 1 mg/L of COD concentration is reduced by using 35 pieces of EM mudballs within the 10000m3 of polluted water in two days. The estimated cost is RM 22.75.
Kim Fie Chew
2015-10-01T00:14:05Z
2017-06-21T00:39:34Z
http://eprints.utm.my/id/eprint/id/eprint/47917
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47917
2015-10-01T00:14:05Z
Combine holts winter and support vector machines in forecasting time series
This study proposes on a combine methodology that exploits the Holts- Winter (HW) model and the Support Vector Machines (SVM) model in forecasting time series. Problems of forecasting using time series data have been and still being addressed at every sphere of research using different approaches. The performance of the forecast was compared among the three models, the HW model, the SVM model and the combine model (HW and SVM). Four different data sets namely, airline passengers’ data, machinery industry production data, clothing industry data and sugar production data were considered in the study. The statistical measures such as mean squared error (MSE), mean average error (MAE) and correlation coefficient, R, were used to evaluate the performance of the propose model. The result of this study indicated that the combine model shows an improvement of 149.3% over HW model and 35.9% improvement over the SVM model for the airline passengers’ data. The result of the machinery industry presented that the combine model shows an improvement of 93.3% over HW model and 42.8% improvement over the SVM model. In the case of the clothing industry the result shows the combine model gives an improvement of 61.6% over HW model and 12.0% improvement over SVM model. Lastly, with respect to the sugar production, the result shows that the combine model indicated an improvement of 34.4% over HW model and 25.1% improvement over SVM model. Therefore the results of the experiments suggest that the proposed combine model is more reliable in time series when compared with the individual models.
Alfa Mohammed Salisu
2015-10-01T00:13:25Z
2017-07-11T03:28:50Z
http://eprints.utm.my/id/eprint/id/eprint/47916
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47916
2015-10-01T00:13:25Z
Intraguild predation model (IGP) with disease
Intraguild Predation (IGP) classified as killing and eating among potential competitors. Intraguild Predation is ubiquitous interaction, differing from competition or predation. The purpose of this study is to investigate the effects of disease on the susceptible prey. Here we analyze the LotkaVolterra competition model and Intraguild Predation model. In order to keep the model simple, an assumption has been made that is no any migration or immigration for the intraguild predator and intraguild prey. We also analyze using the SI model, the simplest epidemiological model. We analyzed the entire model by finding the stability of the equilibrium points by using Routh – Hurwitz criteria. Numerical example is used to show the stability of the equilibrium point by using the MAPLE software.
Aimi Nuraida Ali Hassan
2015-10-01T00:12:47Z
2017-06-29T06:19:56Z
http://eprints.utm.my/id/eprint/id/eprint/47824
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47824
2015-10-01T00:12:47Z
Exact solutions of unsteady free convection flow past an oscillating plate with newtonian heating
The motion of a viscous fluid caused by the oscillations of a vertical plate is important in many applied problems such as acoustic streaming around an oscillating body and an unsteady boundary layer with fluctuations. In boundary layer, free convection flow is a motion that results from the interaction of gravity with density differences within a fluid. These differences occur due to temperature or concentration gradients or due to their composition. The situation where the heat be transported to the convective fluid via a bounding surface having finite heat capacity is known as Newtonian heating (or conjugate convective flows). This configuration occurs in convection flows set up when the bounding surfaces absorb heat by solar radiation. In this thesis, the unsteady free convection flow of an incompressible viscous fluid past an oscillating vertical plate with Newtonian heating is studied. The free convection flow with either heat or heat and mass transfer with radiation effect is considered. The problem of magnetohydrodynamic free convection flow in a porous medium is also studied. Appropriate non-dimensional variables are used to reduce the dimensional governing equations along with imposed initial and boundary conditions into dimensionless forms. The exact solutions for velocity, temperature and concentration are obtained using the Laplace transform technique. The corresponding expressions for skin friction, Nusselt number and Sherwood number are also calculated. The graphical results are displayed to illustrate the influence of various embedded parameters such as Newtonian heating parameter, radiation parameter, Grashof number and phase angle. The results obtained show that the effect of Newtonian heating parameter increases the Nusselt number but reduces the skin friction. However, the Nusselt number is decreased when the radiation parameter is increased. Also, the skin friction is decreased when the radiation parameter, phase angle and Grashof number are increased.
Abid Hussanan
2015-10-01T00:12:04Z
2017-06-22T02:49:11Z
http://eprints.utm.my/id/eprint/id/eprint/45444
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/45444
2015-10-01T00:12:04Z
The effect of Yb3+ on corrosion of lead oxychloride tellurite glasses
A series of tellurite glasses based on (80-x)TeO2-10PbO-10PbCl2-xYb2O3 where 0.0 = x = 3.0 mol% had successfully been prepared by conventional melt quenching technique. The glass was stable in air and the structural phase was determined using X-ray diffraction technique. The transition temperature, Tg and the crystallization temperature, Tc were determined using differential thermal analyser, DTA. Meanwhile, the density and molar volume of the glass were determined by using Archemedes technique. The glass durability was determined by the measurement of its corrosion rate in acidic solution, alkaline solution and in distilled water. It was found that the glass was amorphous as no peak existed in the X-ray diffraction spectra. It was also found that the Tg and Tc increased as the Yb3+ content was increased. It was observed that the glass density increased while molar volume decreased with increasing Yb3+ content. The corrosion rate in acidic solution, alkaline solution and distilled water were in the range of (2.46 to 52.04) ? 10-7 gmm-2 day-1, (0.90 to 2.87) ? 10-7 gmm-2day-1 and (1.13 to 2.59) ? 10-7 gmm-2day-1, respectively. It was generally expected that the degradation of glass was due to the ion exchange mechanism and diffusion controlled process
Muhammad Abdullah Izat Mohd. Yassin
2015-10-01T00:08:39Z
2017-07-19T06:42:56Z
http://eprints.utm.my/id/eprint/id/eprint/44666
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/44666
2015-10-01T00:08:39Z
Multivariate disaggregation of daily to hourly rainfall series
This study focuses on a method to disaggregate daily rainfall into hourly precipitation. This method uses the multivariate technique in generating a small scale data from a larger scale data. In this method, the lower-level synthetic series must be consistent with the higher-level series. Hence, this method would involve a spatialtemporal rainfall modeling that combines several univariate and multivariate rainfall models operating at different timescales, in a disaggregation framework that can appropriately modify outputs of finer timescale models so as to become consistent with given coarser timescale series. The methodology can be applied to derive spatially consistent hourly rainfall series in rain gauge where only daily data are available. The simulation framework provides a way to take simulations of multivariate daily rainfall and generate multivariate fields at fine temporal resolution. In this study, rainfall stations with daily and hourly scale data in Johor are used. The multivariate method would emphasis on using several daily data from the nearby stations to be disaggregated to hourly scale data. According to literature this method has shown promising results in other countries. This method has the ability to preserve important properties of the hourly rainfall process such as marginal moments, temporal and spatial correlations, and proportions and lengths of dry intervals. Multivariate rainfall disaggregation models have greater potential in hydrological applications including enhancement of historical data series and generation of simulated data series.
Tou Hin Lim
2015-07-07T01:58:16Z
2017-08-14T01:35:08Z
http://eprints.utm.my/id/eprint/id/eprint/47890
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47890
2015-07-07T01:58:16Z
In-vitro characterization of antibacterial bioactive glass containing ceria
Yi-Fan Goh
Ammar Z. Alshemary
Muhammad Akram
Mohammed Rafiq Abdul Kadir
Rafaqat Hussain
2015-07-07T01:58:13Z
2017-08-14T01:22:04Z
http://eprints.utm.my/id/eprint/id/eprint/47830
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47830
2015-07-07T01:58:13Z
Comparison of activity concentration of 238u, 232th and 40k in different layers of subsurface structures in Dei-dei and Kubwa, Abuja, North Central Nigeria
Omeje Maxwell
Husin Wagiran
Noorddin Ibrahim
Kuan Lee Siak
Soheil Sabri
2015-07-07T01:58:13Z
2017-01-31T07:37:10Z
http://eprints.utm.my/id/eprint/id/eprint/47831
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47831
2015-07-07T01:58:13Z
Comparison of EEG source localization using meromorphic approximation to fuzzy c-mean
Electroencephalography (EEG) is a neuroimaging technique for localizing active sources within the brain, from knowledge of electromagnetic measurements outside the head. Recognition of point sources from boundary measurements is an ill-posed inverse problem. InEEG, measurements are only accessible at electrode positions, the number of sources is not known a prior. This paper proposes a comparison between two approaches for EEG source localization. First method based on Meromorphic approximation techniques in the complex plane and second one belongs to EEG’s method which is processed using Fuzzy C-Means (FCM). Comparison results on simulated data are used to verify the superior of the Meromorphic approximation with regarding to Fuzzy c-means, due to it provides the way for solving inverse problem of EEG source localization in 3D from boundary measurement based on Harmon function in the innermost layer.
Leila Saeidias, , ,
Leila Saeidias
Tahir Ahmad
Norma Alias
Mehdi Ghanbari
2015-07-07T01:58:13Z
2017-08-14T01:19:17Z
http://eprints.utm.my/id/eprint/id/eprint/47866
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47866
2015-07-07T01:58:13Z
Fast, slow, stopping and storing light simultaneously using a panda ring on-chip
N. Sarapat
W. Khunnam
S. Chiangga
N. Thammawongsa
M. A. Jalil
Jalil Ali
P. P. Yupapin
2015-07-07T01:58:12Z
2017-06-19T02:56:51Z
http://eprints.utm.my/id/eprint/id/eprint/47840
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47840
2015-07-07T01:58:12Z
Determination of best-fit distribution and rainfall events in Damansara and Kelantan, Malaysia
This paper presents a study to determine the best-f
it distribution to represent the
rainfall process in Damansara and Kelantan, Malaysi
a. Three probability density functions,
namely Wakeby distribution, Generalized Extreme Val
ue function (GEV) and two-parameter
Weibull distributions are selected and compared. Th
e parameters of the distributions are
estimated using L-moments method while the best-fit
distribution is determined by using
Kolmogorov-Smirnov goodness-of-fit test. In additio
n, weighted-average algorithm which is
based on the probability values from the stations i
n Damansara and Kelantan is used to
identify the occurrence of wet and dry events in th
e rainfall data. The impact of different
distributions used in the determination of rainfall
events is evaluated by making comparison
between the actual and the reconstructed rainfall d
ata. The results indicate that the Wakeby
distribution is the best-fit distribution to explai
n the rainfall patterns in Damansara and
Kelantan. However, Wakeby, GEV and Weibull distribu
tions perform equally well in the estimation of wet and dry events in Damansara and Kelantan.
Ming Kang Ho
Fadhilah Yusof
2015-07-07T01:58:12Z
2017-08-14T01:08:09Z
http://eprints.utm.my/id/eprint/id/eprint/47897
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47897
2015-07-07T01:58:12Z
Stokes' second problem for magnetohydrodynamics flow in a burgers' fluid: the cases γ= λ2/4 and γ> λ2/4
Ilyas Khan
Farhad Ali
Sharidan Shafie
2015-07-07T01:58:12Z
2017-08-14T01:07:08Z
http://eprints.utm.my/id/eprint/id/eprint/47898
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47898
2015-07-07T01:58:12Z
Studies of πg9/2+ isomers in odd 67-69 as nuclei by deep-inelastic collisions
I. Hossain
N. N. A. M. A. Ghani
M. A. Saeed
H. Y. Abdullah
K. K. Viswanathan
H. Wagiran
2015-07-07T01:58:12Z
2017-01-31T07:22:15Z
http://eprints.utm.my/id/eprint/id/eprint/47856
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47856
2015-07-07T01:58:12Z
Electro-driven extraction across a polymer inclusion membrane in a flow-through cell
A flow-through arrangement for electrodriven extraction across a polymer inclusion membrane was developed. Sample introduction into the donor chamber was continuous, while the acceptor solution was stagnant. By adjustment of the total volume of the donor solution pumped through the cell the best compromise between enrichment factor and extraction time can be set. The enriched extract was analyzed by capillary electrophoresis with contactless conductivity detection. Membranes of 20 !m thickness were employed which consisted of 60% cellulose triacetate as base polymer, 20% o-nitrophenyl octyl ether as plasticizer, and 20% Aliquat 336. By passing through 10 mL of sample at a flow rate of 1 mL/min the model analytes glyphosate (a common herbicide) and its major metabolite aminomethylphosphonic acid could be transported from the aqueous donor solution to the aqueous acceptor solution with efficiencies >87% in 10 min at an applied voltage of 1500 V. Enrichment factors of 87 and 95 and limits of detection down to 43 and 64 pg/mL were obtained for glyphosate and aminomethylphosphonic acid, respectively. The intra- and interday reproducibilities for the extraction of the two compounds from spiked river water were about 6 and 7% respectively when new membranes were used for each experiment. For consecutive extractions of batches of river water with a single piece of membrane a deterioration of recovery by about 16% (after 20 runs) was noted, an effect not observed with purely aqueous standards.
Heng See Hong
Simone Stratza
Peter C. Hausera
2015-07-07T01:58:11Z
2017-08-14T00:52:59Z
http://eprints.utm.my/id/eprint/id/eprint/47900
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47900
2015-07-07T01:58:11Z
The impact of ASH3 overflow time and indium composition on the formation of self-assembleINXGAa1 − xas quantum dots studied by atomic force microscopy
Didik Aryanto
Zulkafli Othaman
Abd. Khamim Ismail
2015-07-07T01:58:10Z
2017-08-14T00:38:45Z
http://eprints.utm.my/id/eprint/id/eprint/47872
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/47872
2015-07-07T01:58:10Z
Germanium nanoislands grown by radio frequency magnetron sputtering-grown germanium nanoislands: annealing time dependent surface morphology and photoluminescence
Alireza Samavati
Zulkafli Othaman
S. K. Ghoshal
R. J. Amjad
2015-03-22T07:46:09Z
2017-07-24T07:51:31Z
http://eprints.utm.my/id/eprint/id/eprint/31889
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/31889
2015-03-22T07:46:09Z
Application of smoothed particle hydrodynamics method in solving two dimensional shear driven cavity problems
Solution to the two-dimensional (2D) shear driven cavity problem has been done by many researchers earlier. Numerical methods are always being used in solving 2D shear driven cavity problem. The usual numerical method being chosen is the grid-based method such as finite difference method (FDM), finite element method and alternating direction implicit method. However, in this research, the smoothed particle hydrodynamics (SPH) method is chosen and being studied to be applied in solving the 2D shear driven cavity problem. The algorithm for SPH method is also being developed. As for making the comparisons to study on the accuracy of SPH method, 2D shear driven cavity also being solved using FDM. MATLAB and FORTRAN programming are used as a calculation medium for both the FDM and SPH method respectively.
Nadirah Zanal Abidin
2015-03-01T08:59:17Z
2017-09-11T06:20:19Z
http://eprints.utm.my/id/eprint/id/eprint/44616
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/44616
2015-03-01T08:59:17Z
A hybrid Box-Jenkins and decomposition model for drought forecasting in Kuala Terengganu
Drought is a global phenomenon which adversely affects the sustainability of one nation which encompasses three prominent aspects such as economic, social and environmental. Due to that, it has immensely attracted the awareness of environmentalists, ecologists, hydrologists, meteorologists, geologists and agricultural scientists. Therefore, drought forecasting is essential for several key players particularly the governments to evaluate the drought occurrence in order to give early warning for preparedness and mitigation measures. In this study, a hybrid Box-Jenkins and decomposition model based on standardized precipitation index (SPI) was developed to forecast drought in Kuala Terengganu. Monthly rainfall data of rain gauge station, Setor JPS Kuala Terengganu for period January 1982 to January 2012 was used in this study. Multiplicative decomposition method was employed to identify and isolate the underlying components of SPI time series for multiple time scales using Minitab 16.0. Then the isolated components were gone through the four-step iterative procedure of Box-Jenkins which are identification, estimation, diagnostic checking and forecasting. After that, the forecasted values of components were reassembled in order to gain a forecast based on the time series decomposition. The forecasting performance of the hybrid model was compared with the Box-Jenkins model. Two statistical measurements, mean absolute error (MAE) and mean squared error (MSE) were applied in this study to measure the accuracy of the forecasting models. In brief, the accuracy measure results indicated that the hybrid model can prevail over the Box-Jenkins model.
Mee Chyong Ho
2015-02-02T08:23:40Z
2017-06-21T07:44:49Z
http://eprints.utm.my/id/eprint/id/eprint/43968
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/43968
2015-02-02T08:23:40Z
Spectroscopic properties of Nd:YAG laser pumped by flashlamp at various temperatures and input energies
The purpose of this research was to investigate the temperature and energy input dependency of Nd:YAG laser performance pumped by flashlamp. A commercial laser rod Nd:YAG crystal was utilized as a gain medium. The laser rod was placed parallel to a linear flashlamp filled with xenon gas at 450 Torr. The Nd:YAG crystal together with the flashlamp were flooded with a coolant comprising of a mixture of 60% ethylene glycol and 40% distilled water which covers a range of temperature from -30?C to +60?C. Spectroscopic properties of the Nd:YAG rod under pulsed flashlamp pumping was investigated from the output fluorescence spectrum of the flashlamp radiation and the Nd:YAG rod. The linewidth of each fluorescence line was measured for estimation of effective emission cross section and saturation intensity. The influence of temperature and input energy on fluorescence emission cross section of Nd3+:YAG crystal was studied. The cross section was found to decrease as the temperature and the input energy were increased. The inter-stark emission showed Lorentzian line shape indicating homogeneous broadening. This was attributed to the thermal broadening mechanism of the emission line. The spectral widths and shifts of the emission lines for the three and four level inter-Stark transitions within the respective intermanifold transitions of 4F3/2›4I9/2 and 4F3/2›4I11/2 were investigated over the range of 0 to 75 J. The emission lines for the 4F3/2›4I9/2 transitions shifted towards a longer wavelength and broadened, while the positions and linewidths for the 4F3/2›4I11/2 transitions remained unchanged with increasing input energy. Finally the temperature dependence of quasi three level laser transitions for long pulse Nd:YAG laser was also investigated. The laser performance at 938.5 nm and 946.0 nm were also found to be inversely proportional with temperature and the slope efficiency was unchanged to temperature. The reduction was due to the mechanism of phonon scattering as well as broadening effect as the temperature increases.
Seyed Ebrahim Pourmand
2015-02-02T08:20:38Z
2017-06-22T02:28:43Z
http://eprints.utm.my/id/eprint/id/eprint/43966
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/43966
2015-02-02T08:20:38Z
Conjugacy classes and graphs of two-groups of nilpotency class two
Two elements a and b of a group are called conjugate if there exists an element g in the group such that gag??1 = b: The set of all conjugates in a group forms the conjugacy classes of the group. The main objective of this research is to determine the number and size of conjugacy classes for 2-generator 2-groups of nilpotency class two. Suppose G is a 2-generator 2-group of class two which comprises of three types, namely Type 1, Type 2 and Type 3. The general formulas for the number of conjugacy classes of G are determined by using the base group and central extension method, respectively. It is found that for each type of the group G, the number of conjugacy classes consists of two general formulas. Moreover, the conjugacy class sizes are computed based on the order of the derived subgroup. The results are then applied into graph theory. The conjugacy class graph of G is proven as a complete graph. Consequently, some properties of the graph related to conjugacy classes of the group are found. This includes the number of connected components, diameter, the number of edges and the regularity of the graph. Furthermore, the clique number and chromatic number for groups of Type 1, 2 and 3 are shown to be identical. Besides, some properties of the graph related to commuting conjugacy classes of abelian and dihedral groups are introduced.
Sheila Ilangovan
2015-02-02T08:18:07Z
2017-07-23T06:07:24Z
http://eprints.utm.my/id/eprint/id/eprint/43963
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/43963
2015-02-02T08:18:07Z
Computational modelling and simulation of biomagnetic fluid flow in a stenotic and aneurysmal artery
This thesis is concerned with the development of mathematical models for the computation and simulation of biomagnetic fluid flow in either a stenosed or aneurysmal artery in the presence of non-uniform magnetic fields. The mathematical models take into account blood rheology where blood behaves as a magnetic fluid due to the complex interaction of intercellular protein, cell membrane and haemoglobin. The present study involves steady three-dimensional biomagnetic fluid flow and mass transfer through a horizontal cylinder. Numerical solutions obtained through a finite volume method shows that the magnetisation force has an effect on the fluid concentration and exerts a greater influence on the secondary flow motions compared to that caused by the Lorentz force. Earlier studies allow only Lorentz force due to uniform magnetic fields but neglect the effect of magnetisation force. Here, a modified finite difference method has also been designed specifically to study separately the effect of magnetisation force, Lorentz force or both, on a steady two-dimensional channel flow. It is observed that a distorted asymmetric flow profile is presented near the magnetic source and that the Lorentz force gives little influence to the flow behaviours, vindicating previous proposition that the Lorentz force need not be considered in the model of biomagnetic fluid flow.
Nursalasawati Rusli
2015-02-02T08:17:19Z
2017-06-21T05:00:39Z
http://eprints.utm.my/id/eprint/id/eprint/43962
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/43962
2015-02-02T08:17:19Z
Effect of silver nanoparticles on optical properties of erbium-doped magnesium phosphate glass
Three series of phosphate glass with composition (59.5-x)P2O5-40MgOxAgCl-0.5Er2O3 (0.0≤x≤1.5 mol%), (59.5-x)P2O5-40MgO-xAgCl-1.5Er2O3(0.0≤x≤1.5 mol%) and (69.7-x)P2O5-30MgO-0.3Er2O3-xAgCl, where x=0 or 0.5mol% were prepared using melt quenching technique. The amorphous nature of theglass was confirmed using the X-ray diffraction (XRD) method. The homogeneousdistribution of spherical Ag nanoparticles (NPs) (average size of 37 nm) in the glassymatrix was evidenced from the transmission electron microscopy (TEM) analyses.The UV-VIS-NIR absorption spectra showed 7 bands corresponding to 4I13/2, 4I11/2,4I9/2, 4F9/2, 4S3/2, 2H11/2, 4F7/2 transitions. The absorption spectrum of Er3+ ions freeglass sample containing Ag NPs displayed a prominent surface plasmon resonance(SPR) band located at ~528 nm. The infrared to visible frequency up-conversion(UC) emission under 797 nm excitation showed two emission bands of green (4S3/2-4I15/2) and red (4F9/2-4I15/2) corresponding to Er3+ transitions. An enhancement in UCemission intensity of both green and red bands was observed in the presence of silverNPs either by increasing annealing time or by NPs concentration. The enhancementof UC emission was understood in terms of the intensified local field effect due tosilver NPs. For first series of samples, the Judd-Ofelt parameters (Ω2, Ω4 and Ω6)were calculated and were found to lie in the range (8.05-9.20) ×10-20 cm2, (2.00-2.58)×10-20 cm2 and (1.05-2.30) ×10-20 cm2 respectively. These parameters were used toestimate the important parameters such as radiative transition probability (A),stimulated emission cross-section, radiative life time (τR) and branching ratio(βR) for the excited levels of Er3+ ions in the glass. Furthermore, the value of Ω2 forthe studied glasses was found to be higher than that of glasses reported in theliterature. These relatively higher values of Ω2 reflect low symmetry and highcovalency around the Er3+ ions. These phosphate glass nanocomposites can bepotentially used as photonic and plasmonic materials.
Muhammad Junaid Amjad
2014-10-13T01:31:00Z
2017-08-01T01:35:28Z
http://eprints.utm.my/id/eprint/id/eprint/40691
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40691
2014-10-13T01:31:00Z
Long distance communication using localized optical soliton via entangled photon
A system of microring resonators (MRRs) is presented to generation entangled photon. Different time slot for continuous variable quantum key distribution (CVQKD) use is applicable in optical wireless link. Chaotic behavior of a soliton pulse within the device can be presented respect to the Kerr nonlinear type of light in the MRR devices. Continuous spatial and temporal signals are generated spreading over the spectrum. The CVQKD is formed using the localized spatial soliton pulse. Here localized temporal soliton with FWHM and FSR of 0.2 ps and 0.58 ns is obtained respectively. The spatial soliton pulse has a FWHM of 80 pm. Transmission of soliton pulse with FWHM of 1.5 ps is simulated along the long distance fiber optics where the polarized photons are formed incorporating with the polarization control unit into the MRRs, which allows different time slot entangled photons to be randomly formed.
I. S. Amiri
Gifany D.
Jalil Ali
2014-10-13T01:29:10Z
2017-08-01T01:32:16Z
http://eprints.utm.my/id/eprint/id/eprint/40690
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40690
2014-10-13T01:29:10Z
Logic codes generation and transmission using an encoding-decoding system
Nonlinear behaviors of light such as chaos can be observed during propagation of a Gaussian laser beam inside a single ring resonator system. Chaotic signals can be employed to generate data of logic codes to be transmitted along the fiber optic communication. Controlling of the chaotic signals can be implemented by the parameter of the system such as coupling coefficient, the ring’s radius, coupling loss and input power. The central wavelength of the input Gaussian laser pulse has been selected to λ0=1550 nm where the nonlinear refractive index of the medium is n2=1.4×10−13 m2 W−1. Therefore the data of logic codes generated by the single ring resonator system can be converted to transmitting secured codes where the decoding process of the transmitted codes can be obtained at the end of the transmission link. Here generation of logic code of “101010101011010101011101011110101101010101010110101” is performed, encoded and decoded over 50 km fiber optics. Thus secured transmitting of signals can be obtained along the long distance fiber communication.
Gifany D.
I. S. Amiri
M. Ranjbar
Jalil Ali
2014-10-12T08:46:07Z
2017-11-01T04:17:12Z
http://eprints.utm.my/id/eprint/id/eprint/40699
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40699
2014-10-12T08:46:07Z
Mathematical thinking in differential equations among pre-service teachers
Pre-service teachers should be equipped with mathematical thinking. Mathematical thinking is one of the most critical aims of the mathematics education has an extremely crucial role for enhancing then conceptual learning. Mathematical thinking is a process that enables students to expand the for the complexities of their ideas. This article describes mathematical thinking in differential equations among pre-service teachers. The study was carried out in the Faculty of Education, Universiti Teknologi Malaysia. A set of items was designed to test mathematical thinking level. The instrument was developed based on Mason's framework of mathematical thinking. Test items measure mathematical thinking namely, specializing, generalizing, conjecturing, and convincing. Descriptive statistics was applied for data analysis. The result indicated that students' mathematical thinking is in the low level mostly specializing. The implications of this research will lead to some recommendations and approaches to enhance mathematical thinking.
Fereshteh Zeynivandnezhad
Zaleha Ismail
Yudariah Mohammad Yosuf
2014-10-09T10:57:10Z
2020-08-23T06:32:36Z
http://eprints.utm.my/id/eprint/id/eprint/42256
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42256
2014-10-09T10:57:10Z
Catalytic chelation technique for the removal of toxic and heavy metals from green mussel, perna viridis
Malaysian mussels can be contaminated with toxic and heavy metals which are cumulative poison through long term ingestion. Currently, no commercially viable technology has been developed for the removal of these toxic and heavy metals from contaminated mussels. Therefore, the purpose of the study is to develop method that safely removes metals from contaminated mussels so as to comply with the permissible limit set by the Malaysian Food Regulations (1985) and Commission Regulation of EU (2006) for human consumption. The removal of toxic and heavy metals in mussels by catalytic chelation method was studied using three types of chelating agent salts, namely trisodium citrate, disodium oxalate and sodium acetate. Three types of catalysts supported on Al2O3, namely MgO, BaO and CaO were used. The preliminary treatment conditions was carried out using trisodium citrate at a concentration of 500 mg/L, one hour treatment time, treatment temperature of 32.5±0.5oC and pH 7-8. All metals analysis were carried out using inductively coupled plasma mass spectrometry technique. The study shows that female mussel accumulates higher concentration of toxic and heavy metals as compared to male mussel. The results indicated that sodium acetate gave the highest percentage removal of toxic and heavy metals (As 59.50%, Pb 88.57%, Cd 68.01% and Ni 79.67%) followed by disodium oxalate (As 46.89%, Pb 85.46%, Cd 60.41% and Ni 47.80%) and trisodium citrate (As 38.13%, Pb 68.90%, Cd 70.49% and Ni 36.92%). Thus, all treatment conditions were optimized according to sodium acetate in subsequent study. The presence of catalysts improved toxic and heavy metals removal in mussels. Among the three catalysts studied, CaO catalyst gave the highest percentage removal (As 46.89%, Pb 85.46%, Cd 60.41% and Ni 47.80%) followed by BaO and MgO at an optimum calcination temperature of 1000oC. XRD analysis revealed the active sites were due to the presence of orthorhombic Al2O3, monoclinic CaAl4O7/CaO.2Al2O3 and cubic Ca12Al14O33 species. Meanwhile, FESEM analysis displayed the formation of homogeneous particles with undefined shape, aggregated and agglomerated on the catalyst surface. BET surface area study gave a surface area of 33.22 m2/g. EDX analysis showed a weight percentage of O=57.43%; Al=35.93%; Ca=6.64%. FTIR analysis showed total removal of metal precursor by CaO/Al2O3 catalyst at 1000oC calcinations temperature.
Ihsan Wan Azelee
2014-10-09T10:57:10Z
2014-10-09T10:57:10Z
http://eprints.utm.my/id/eprint/id/eprint/42257
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42257
2014-10-09T10:57:10Z
Computational study of vinpocetine-teicoplanin aglycone complex as a chiral selector
Noor Syamimi Abdul Manan
2014-10-09T10:57:10Z
2014-10-09T10:57:10Z
http://eprints.utm.my/id/eprint/id/eprint/42261
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42261
2014-10-09T10:57:10Z
Quantum chemical study of proton transfer mechanism of hydrated single and double propyl sulfonic acid
Syarah Mat Udin
2014-10-09T09:21:50Z
2020-07-28T02:21:46Z
http://eprints.utm.my/id/eprint/id/eprint/42060
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42060
2014-10-09T09:21:50Z
Adsorption of selenite ion from aqueous solution by solid pineapple waste
In the pineapple canning industry, almost forty percent of pineapple portion is rejected during the production process. Most of the rejected portion is used as ruminant and for alcohol production. In the present study, the untreated solid pineapple waste (SPW) was used to adsorb selenite ion (Se(IV)) from aqueous solution. The Se(IV) loaded and unloaded SPW were characterized using proximate analysis, atomic absorption spectrometry, scanning electron microscopy, energydispersive X-ray spectroscopy, thermogravimetry analysis, differential scanning calorimetry and Fourier transform infrared spectroscopy. Various parameters that affect the adsorption such as initial pH, contact time, temperature, mass of adsorbent and concentration of adsorbate were investigated to determine the optimum adsorption conditions. Kinetics of the adsorption was investigated by pseudo firstorder and pseudo second-order models. Equilibrium studies were carried out by Langmuir, Freundlich and Temkin isotherms. Thermodynamic studies of the adsorption were performed using van’t Hoff equation. Desorption studies of the Se(IV) loaded SPW were carried out under various conditions such as initial pH, desorption time, ratio mass of loaded SPW to reaction volume and concentrations of humic acid and competing ions such as chloride, phosphate and sulphate ions. Under the optimum adsorption conditions the Se(IV) content of SPW could be increased by 100 folds from less than 10 µg/g to nearly 1000 µg/g. The adsorption optimum conditions were at pH 6, adsorption duration t = 60 min, initial concentration of Se(IV) aqueous solution C0 = 10 mg/L, SPW weight was 3 g in 50 mL of reaction volume and temperature was 80°C. The adsorption rate of Se(IV) by SPW under the optimum conditions fitted the pseudo second order with rate constant, k2 = 4.8539 mg/g min while the adsorption of Se(IV) by SPW best fitted Temkin isotherm (R2 = 0.9963), followed by Langmuir isotherm (R2 = 0.9830) and the Freundlich isotherm (R2 = 0.9702), which indicated the dominance of chemisorption. The van’t Hoff equation applied to this adsorption indicated that the adsorption process is endothermic, favourable and spontaneous. The adsorbed Se(IV) can be leached out gradually under the influences of pH, ratio of mass of loaded SPW to reaction volume and the presence of humic acid, phosphate, sulphate and chloride ions
Erna Izaini Zakaria
2014-10-09T09:21:49Z
2014-10-09T09:21:49Z
http://eprints.utm.my/id/eprint/id/eprint/42068
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42068
2014-10-09T09:21:49Z
Analysis for suitability of refuse dump site locations in Keffi using GIS
Ibrahim Sufiyan
2014-10-09T09:21:49Z
2020-08-10T08:10:56Z
http://eprints.utm.my/id/eprint/id/eprint/42173
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42173
2014-10-09T09:21:49Z
Modified metal oxides supported on polyvinyl chloride catalysts for the photodegradation of paraquat dichloride
The use of heterogeneous photocatalyst based on titanium dioxide has been proven as an effective treatment method for polluted water. In this research, titanium dioxide (TiO2), zinc oxide (ZnO) and tungsten trioxide (WO3) were used to prepare monometallic, bimetallic and trimetallic oxide photocatalysts using simple sonication and ball milling techniques with different weight percents of metal oxide. These metal oxides were then used to prepare metal oxides supported on polyvinyl chloride (MO/PVC). Multiwalled carbon nanotubes (MWCNT) was added in MO/PVC to give MO/PVC-MWCNT photocatalyst and was applied for photodegradation of paraquat dichloride. The treated paraquat dichloride solution was measured using ultraviolet-visible spectrophotometric technique. The best loading of metal oxides on PVC support was achieved at 80 weight percent which showed the total amount of catalyst is 4.0 g. This loading was used throughout the research. The effect of pH, H2O2 addition and sonication treatment time were also studied to determine the optimum reaction condition. Comparison using different preparation techniques between simple sonication and ball milling showed that simple sonication was preferred to prepare bimetallic and trimetallic oxide photocatalysts. The photocatalytic activity increased with the introduction of MWCNT for monometallic oxide but decreased for bimetallic and trimetallic oxide photocatalysts. The optimization of MWCNT loading for TiO2/PVC-MWCNT photocatalyst was successfully achieved when the ratio of MWCNT:TiO2 was at 1.19:98.81 which gave 73.55% degradation of paraquat dichloride. The activity of TiO2/PVC with 20 ppm H2O2 addition was the best which gave 76.57% paraquat dichloride degradation, followed by the activity of TiO2/PVC-MWCNT with the aid of 30 minutes sonication treatment which gave 74.37% paraquat degradation. The activity of TiO2/PVC-MWCNT and WT/PVC-MWCNT both gave 73.55% paraquat dichloride degradation. FESEM micrograph of MO/PVC-MWCNT photocatalysts showed that the MWCNT were covered by the metal oxides. EDX analysis confirmed the presence of Ti, Zn, W and O elements in the prepared photocatalysts. XRD patterns showed the degree of crystallinity of TiO2 powder was higher than TiO2 supported on PVC.
Wan Noralwani Wan Zamry
2014-10-09T09:21:49Z
2017-07-11T00:26:41Z
http://eprints.utm.my/id/eprint/id/eprint/42113
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42113
2014-10-09T09:21:49Z
Electroanalytical studies of glyphosate and aminomethylphosphonic acid in aqueous medium using copper and hanging mercury drop electrodes
Glyphosate (GLYP) is commonly used in agriculture to control weeds. GLYP residue and its main metabolite, aminomethylphosphonic acid (AMPA), can be found in crops, vegetables, fruits, soil and also ground water which raised concern over the problems regarding to the environmental contaminations. These compounds can be detected and determined by gas chromatography (GC), high performance liquid chromatography (HPLC), ion chromatography (IC), capillary electrophoresis (CE) or enzyme linked immunosorbent assay (ELISA). However, most of these methods are time consuming, involve the use of toxic solvents, require complicated pre-preparation and high cost of instrumentation. Therefore, in the present study voltammetric method based on the use of copper electrode (CuE) and hanging mercury drop electrode (HMDE) were used to investigate the electrochemical behaviour and quantitative analysis of GLYP and AMPA. Investigations were carried out by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and differential pulse cathodic stripping voltammetry (DPCSV) techniques based on the reduction (cathodic current) and oxidation (anodic current) of Cu(II) in phosphate buffer at pH 6.4. Based on anodic and cathodic currents of the CuE working electrode using DPV and DPCSV techniques, linear calibration curves were obtained in the range of 1.18 up to 5.92 × 10-6 M and 7.20 up to 36.02 × 10-6 M for GLYP and AMPA respectively. The limits of detection (LOD) based on anodic current for GLYP at -80 mV vs saturated calomel reference electrode (SCE) and AMPA at -96 mV vs SCE by DPV technique were 3.24 × 10-7 M and 2.68 × 10-6 M respectively. The LOD based on cathodic current for GLYP at -180 mV vs silver/silver chloride reference electrode (Ag/AgCl) and AMPA at -190 mV vs Ag/AgCl were 4.69 × 10-7 M and 2.67 × 10-6 M respectively. The LOD by DPCSV with CuE working electrode were 3.11 × 10-7 M and 2.09 × 10-6 M for GLYP at -180 mV vs Ag/AgCl and AMPA at -190 mV vs Ag/AgCl respectively. Determination of GLYP and AMPA by HMDE requires addition of Cu(II) into the test solution. Linear calibration curves by HMDE were obtained in the range of 2.96 up to 14.79 × 10-7 M and 1.35 up to 6.75 × 10-6 M for both DPV and DPCSV. The LOD of GLYP at 0 mV vs Ag/AgCl and AMPA at -3 mV vs Ag/AgCl by HMDE were 7.41 × 10-8 M and 6.05 × 10-7 M respectively using DPV. The LOD by DPCSV technique for GLYP at -3 mV vs Ag/AgCl and AMPA at 0 mV vs Ag/AgCl by HMDE were 5.40 × 10-8 M and 2.64 × 10-7 M respectively. The DPCSV technique with CuE and HMDE working electrodes for the determination of GLYP and AMPA have good recoveries (94 - 98%) based on application to real samples.
Nor Hafizah Yasin
2014-10-09T09:21:49Z
2017-07-11T00:24:50Z
http://eprints.utm.my/id/eprint/id/eprint/42215
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42215
2014-10-09T09:21:49Z
Synthesis and bioactivity studies of coumarin and its derivatives
Coumarin is a naturally occurring compounds being present in several plants and also can be produced through organic synthetic reactions. In this study, substituted coumarins of 3-acetylcoumarin, 3-acetyl-7-(diethylamino)coumarin, 7-(diethylamino)-3-(1-oxobutyl)coumarin, 3-oxobutyl-3H-naphtho[2,1-b]pyran-2- one, 6-bromo-3-(1-oxobutyl)coumarin and 8-methoxy-3-(1-oxobutyl)coumarin were synthesized via Knoevenagel condensation reaction of respective 2-hydroxybenzaldehyde derivatives with active methylene group from ethyl acetate or ethyl butyrylacetate under basic condition. Meanwhile, 7-hydroxy-4-methylcoumarin, 4-methyl-2H-benzo[h]chromen-2-one, 7-hydroxy-4,8-dimethylcoumarin, 7-hydroxy- 4-propylcoumarin, 4-propyl-2H-benzo[h]chromen-2-one, 7-hydroxy-8-methyl-4- propylcoumarin and 7,8-dihydroxy-4-propylcoumarin were prepared through Pechmann condensation reaction by the condensation of respective substituted phenol and ß-keto-ester in the presence of sulphuric acid as a catalyst. Futher methylation reaction on 7-hydroxy-4-methylcoumarin with iodomethane catalysed by K2CO3 gave 7-methoxy-4-methylcoumarin. Modification of hydroxyl group of 7,8-dihydroxy-4-propylcoumarin using butyric anhydride and dry pyridine yielded 7,8-bis-(1-oxobutoxy)-4-propylcoumarin. In addition, 7-hydroxy-4,8-dimethylcoumarin was converted to 7-benzyloxy-4,8-dimethylcoumarin through reaction of benzyl chloride in dry acetone. In addition, 7,8-methylenedioxy-4-propylcoumarin undergoes Williamson etherification reaction which involved SN2 mechanism between secondary alkyl halide with potassium salt of a phenoxide. All compounds were characterized by spectroscopic techniques using infrared (IR), proton and carbon nuclear magnetic resonance (1H and 13C NMR), and mass spectrometry (MS). The synthesized compounds were tested for their antioxidant and antibacterial activities. It was found that the hydroxylated coumarin derivatives of 7,8-dihydroxy-4-propylcoumarin were tested positive towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with IC50 value of 4.09 ?g/mL while other hydroxylated compounds were inactive. The antibacterial activity show that 6-bromo- 3-(1-oxobutyl)coumarin exhibited as strong antibacterial agent against B. subtilis bacteria with MIC value 56.25 ?g/mL. 7,8-Methylenedioxy-4-propylcoumarin showed strong activity to all Gram-positive bacteria.
Kok Tong Wong
2014-10-09T09:21:48Z
2014-10-09T09:21:48Z
http://eprints.utm.my/id/eprint/id/eprint/42078
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42078
2014-10-09T09:21:48Z
Chemical constituents and bioactivities of Amomum uliginosum J. Konig and Amomum cardamomum L.
Nurul Syafiqah Rezali
2014-10-09T09:21:48Z
2017-07-06T03:42:37Z
http://eprints.utm.my/id/eprint/id/eprint/42088
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42088
2014-10-09T09:21:48Z
Deposition of zinc oxide on zinc plates for photocatalytic removal of dyes in aqueous system
This research involves modification of Zn pure and Zn alloy plates to be utilized for dye removal. The modification is aimed to produce ZnO layer on the surface of Zn pure and Zn alloy plates. Sand blasting technique is used to remove a naturally formed oxide layer on Zn pure and Zn alloy plates. The sand blasting technique is also intended to produce a curved groove site to strengthen the ZnO layer formed on the surface of modified Zn pure and Zn alloy plates. The modification of Zn pure and Zn alloy plates consist of three different methods, electrolysis, immersing in H2O2 and heating. Based on the analysis of DR UV-Vis, SEM and XRD, all three modification methods successfully produced ZnO layer on Zn pure and Zn alloy plates. The formation of ZnO layer is different in thickness and electrolysis is chosen as the best technique for the ZnO layer production. Methylene blue dye (20 ppm, pH 6.56) is utilized as a sample solution to study the removal activity of modified Zn pure and Zn alloy plates. Results obtained from UV-Vis spectra shows that the percentage of methylene blue removal by modified Zn pure plate and was 81.9% and 70.0% respectively Zn alloy plate. Results also showed that adsorption and photocatalysis are involved in the removal of methylene blue dye. Adsorption becomes a major contributor for the removal of methylene blue dye where it contributes 50% of methylene blue removal and photocatalysis only contributes 30% of methylene blue removal. It was also observed that desorption of the methylene blue will occur if the plates are placed in beaker containing distilled water. Modified Zn pure and Zn alloy plates have a “weak adsorption” and “strong desorption” characteristics. The “weak adsorption” and “strong desorption” behaviours of the modified Zn pure and Zn alloy was utilized to create an integrated chemical for application in wastewater treatment in textile industry. This system combines adsorption and photocatalysis techniques for the removal of dye molecules in textile wastewater. The main benefit of this system is that it can separate the dye molecules from wastewater by weak adsorption and transferred dye molecule into a special tank by “strong desorption”. The transferred dye molecules could be recycled and used again by the factories.
Syaiful Akhmal Saadon
2014-10-09T09:21:48Z
2020-08-17T02:26:00Z
http://eprints.utm.my/id/eprint/id/eprint/42194
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42194
2014-10-09T09:21:48Z
Phytochemicals and bioactivity of Piper porphyrophyllum N. E. Br. and Piper sarmentosum Roxb.
Chemical investigations of Piper porphyrophyllum N. E. Br. and Piper sarmentosum Roxb. have been carried out. The stems of P. porphyrophyllum and the whole plant of P. sarmentosum, each were extracted by maceration using petroleum ether, dichloromethane, ethyl acetate and methanol consecutively. Purification of the crude extracts was carried out using several chromatographic techniques. The structures of the pure compounds were elucidated by spectroscopic methods such as IR, 1D (1H, 13C, DEPT) and 2D (COSY, HMQC, HMBC) NMR and GC-MS. Four compounds have been identified from the petroleum ether extract of P. Porphyrophyllum and were characterized as ß-sitosterol, sesamin, N-isobutyl-15- (3’,4’-methylenedioxyphenyl)-2E,4E,12E-pentadecatrienamide and a new compound, 5-hydroxy-7,2’,4’,6’-tetramethoxyflavone. Meanwhile, 5,7,3’,4’,5’- pentamethoxyflavone was identified from the dichloromethane extract. Four compounds were isolated from P. sarmentosum. The petroleum ether extract afforded 3’,4’-methylenedioxyphenyl-13-tetradecene while the dichloromethane extract gave asaricin and 2-(methyl-2’-propenoate)-4,5- methylenedioxybenzaldehyde. Purification of the methanol extract gave 4-(2’- octenyl)phenol. Pure compounds which were isolated abundantly were screened for cytotoxic study using methylthiazol tetrazolium (MTT) cell proliferation assay. 4- (2’-Octenyl)phenol was found to have the highest cytotoxic effect towards the cell with the percentage of cell inhibition of 12.96%.
Raihan Murni Sidek
2014-10-09T09:21:48Z
2020-08-18T06:50:50Z
http://eprints.utm.my/id/eprint/id/eprint/42213
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42213
2014-10-09T09:21:48Z
Structural properties of nanostructured lithium manganese oxide as cathode in lithium ion batteries
Lithium manganese oxide, LiMn2O4 is one of the most promising cathode materials for lithium secondary batteries due to its low cost and environmental benign. LiMn2O4 nanorods have been successfully prepared via sol-gel method using citric acid as chelating agent while polycarbonate membrane as the template. The template was soaked in LiMn2O4 sol and dried for 48 hours before calcined in air at 400°C for 5 hours. These nanorod arrays aligned almost parallel to each other with average diameter and length of 150 nm and 8 µm, respectively. The thermal behavior of LiMn2O4 precursor and polycarbonate membrane were analyzed prior to LiMn2O4 nanorods preparation. BET surface area measurement showed that LiMn2O4 nanorods have large surface area of 44.83 m2/g. The nanorod surface area was higher than those prepared LiMn2O4 nanosized particles. X-Ray diffraction results demonstrated that LiMn2O4 nanorods material has the spinel LiMn2O4 phase with no impurities and the stoichiometry resembled LiMn2O4
Sunati Otoi
2014-10-09T09:21:47Z
2020-08-18T07:19:02Z
http://eprints.utm.my/id/eprint/id/eprint/42216
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42216
2014-10-09T09:21:47Z
Synthesis and catalytic performance of poly(amidoamine) dendrimer encapsulated lanthanum nanoparticle in claisen-schmidt condensation
A series of poly(amidoamine) (PAMAM) dendrimers with ethylenediamine (EDA) core, having generation numbers 0.5 to 5.0 were successfully synthesized via divergent method. Dendrimers were prepared starting from EDA followed by consecutive Michael addition and ester amidation reaction in methanol. Lanthanum was then encapsulated in the PAMAM dendrimers by reduction of lanthanum(III) nitrate hexahydrate with sodium borohydride to yield the corresponding catalysts, having general formula LaPGx (x= 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 3.5, 4.0, 4.5 and 5.0). The lanthanum encapsulated PAMAM dendrimers were characterized by using FTIR, 1H NMR, fluorescence spectroscopy, FESEM, TEM microscopic techniques and cyclic voltammetry. The 1H NMR spectra indicated that the PAMAM dendrons consist of defect site in their structure and the number of defective molecules increases exponentially with each generation. The excess of EDA reduced the occurrence of these defects, however they cannot be eliminated. In the fluorescence spectra, the appearance of the strong charge transfer band, attributed to n ! "* transition of lanthanum within PAMAM dendrimer encapsulated lanthanum nanoparticle in the range 200 – 250 nm was observed. The morphology of PAMAM dendrimer encapsulated lanthanum nanoparticles was investigated using FESEM and the size of particle was observed to be in the range of 30 – 100 nm. The cyclic voltammetry was used in this study to explore the effect of generation number towards the electrochemical properties of synthesized catalysts. The catalytic properties of PAMAM dendrimer encapsulated lanthanum nanoparticles were tested in the Claisen-Schmidt condensation of acetophenone with benzaldehyde at different temperatures (140ºC, 100ºC and 60ºC) and various mole ratio of acetophenone to benzaldehyde (1:1, 2:1 and 1:2) for 24 hour to produce chalcone. The optimum reaction temperature for the entire catalysts was 140ºC with the acetophenone to benzaldehyde mole ratio of 1:1 where the highest percentage conversion (89.1%) and selectivity (98.2%) were achieved using La(5)P3.0 catalyst. Reaction temperature was found to affect the catalytic activity probably due to the viscosity of reaction mixture that is lower at high temperature such that it facilitates heat and mass transfer of the catalytic system. With regards to La(5)P3.0, the selectivity and conversion for chalcone was substantially increased to 100% and 94.7% respectively, when the acetophenone to benzaldehyde ratio was 2:1. For reusability test, the catalytic performance of the used samples was maintained ! 80% after three cycles without significant loss in activity.
Nadirah Zawani Mohd. Nesfu
2014-10-09T09:21:47Z
2020-08-18T07:29:04Z
http://eprints.utm.my/id/eprint/id/eprint/42217
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42217
2014-10-09T09:21:47Z
Synthesis and characterization of zeolite linde type A from rice husk ash and its application as ammonium removal
The purpose of this study is to synthesis zeolite Linde Type A (LTA) by hydrothermal method, where rice husk ash (RHA) was used as silica source and the prepared zeolite LTA is used in ammonium removal study. Nano-size zeolite LTA was successfully synthesized at aging temperature of room temperature for 72 hours followed by hydrothermal treatment at 55°C for 18 hours while micro-size zeolite was successfully synthesize by hydrothermal treatment at 110°C for 5 hours. The synthesized zeolite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and FTIR spectroscopy. FTIR spectroscopy revealed that asymmetric vibrations of Si – O (bridging and non-bridging) bonds, vibration of symmetric stretching of tetrahedral framework, double four rings (D4R) and T – O tetrahedra. The patterns of which showed a unique characteristic of zeolite LTA were characterized by XRD. Zeolite LTA morphology observed by SEM analysis showed pseudo-spherical, face-less particles and cubic shape for nano-size and micro-size, respectively. Broad particle size ranging from 40 to 400 nm for nano-size zeolite and the average size of 1.0 to 2.5 µm for micro-size were observed. The removal of ammonium ions using zeolite LTA was found that nano-size zeolite has higher efficiency in removing ammonium ion compare to the micro-size zeolite.
Methodius Nawog
2014-10-09T09:21:47Z
2020-08-18T07:37:17Z
http://eprints.utm.my/id/eprint/id/eprint/42218
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42218
2014-10-09T09:21:47Z
Synthesis of tungsten carbide from waste date palm tree carbon by mechanical alloying
The abundance of date palm tree wastes consists of foliar (RDFo), frond (RDFr) and thorn (RDTh) has led to the environmental problem in Saudi Arabia. Thus, in this study, the wastes have been proposed to be used as the precursor for activated carbon (AC) production. TGA studies suggest the temperature of 400°C is suitable for the pyrolysis process of wastes to select the best raw material for the activated carbon production. Activated carbon from RDFr with a specific surface area of 21.5 m2g-1, after analyzed by Nitrogen adsorption analysis (NAA) was chosen and activated chemically using phosphoric acid (H3PO4) as dehydrating agent. The effect of different acid concentration ranging from 10 to 80% (v/v) was studied to produce high surface area of AC. The products were further characterized using proximate analysis, FTIR, NAA and FESEM. The results showed that the pore development of AC produced was influenced by acid concentrations. The highest BET specific surface area of AC, 1247 m2g-1 was achieved by using 60% (v/v) of H3PO4. The selected AC was used as catalyst support in tungsten carbide (WC) synthesis. In this process, WC was prepared from tungsten trioxide precursor and magnesium as reducing agent using mechanical alloying method before undergoing heat treatment at 850°C. The products were characterized using single point BET surface area, XRD and FESEM. XRD analysis showed that the WC hexagonal phase was produced in the presence of tungsten semicarbide hexagonal phase in the final products. This is due to the insufficient ratio of reducing agent and shorter time for alloying process.
Norasyikin Mohd. Mustapha
2014-10-09T09:21:46Z
2017-06-20T07:31:27Z
http://eprints.utm.my/id/eprint/id/eprint/42079
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42079
2014-10-09T09:21:46Z
Chemical enhancement of washed aged bloodstain on porous materials using leucocrystal violet
Blood is an important physical clue material encountered in the cases involving physical violence like murders, assaults, rapes, abortion etc. The examination of bloodstains is of immense value in reconstruction of the scene of crime and linking criminal or the victim with the scene of crime. As criminals now often attempt to clean up the crime scene and it is not known through which conditions the bloodstain has undergone before analysis. The main aim for this study is to investigate the use of leucocrystal violet to develop faint bloodstains from porous materials which will be washed with a commonly available cleaning product. Keeping this aspect in view, bloodstains have been examined after exposure to leucocrystal violet and Luminol (for comparison purpose) in order to assess their effect on the detect ability of serological markers as in blood grouping analysis. This study shows that leucocrystal violet has no destructive effect of samples as well as on elution method for the detection of blood group antigens. However, luminol did show an adverse effect on subsequent blood analysis. Thus, it is concluded that luminol has the most adverse effect on the ABO blood grouping. Based on four cloth matrices that were subjected to chemical enhancements, cotton showed the best chemical enhancement result cumulatively. This is due to chemical composition of cotton that allows chemical reactions to occur. In conclusion, positive identification in case of cloth materials that have been washed with bleaching agent and enhanced with Luminol is less accurate and less reliable to compare with samples treated with Leucocrysal violet in the same condition
Rafeah Pakri Mohamed
2014-10-09T09:21:46Z
2020-08-09T07:23:38Z
http://eprints.utm.my/id/eprint/id/eprint/42161
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42161
2014-10-09T09:21:46Z
Mathematical model for river pollution
River pollution is already a common natural disaster in today’s world due to human’s daily activities. Yet, researchers always come out with tonnes of ideas and alternatives to overcome the situation by hoping that we can save one of the main resources of our daily life. In this dissertation, there are three main purposes in order to finish up this thesis. The most important objective is to formulate a simple mathematical model that involved Advection-Diffusion equation. It consists of coupled equation; pollutant and dissolved oxygen. Both equations are consists of Menten-Michaelis Equation and Heaviside-step function. The main purpose of adding these two terms are just empirical relationship with in the literature review. The derivation of the model will be also attached together with this thesis. Finite difference method (FDM) will be used to solve the problem and used in our simulation. We will transform it into a simpler case. Then, we will investigate the effects of aeration on the degradation of pollutant. Finally, we considered that the problem can be solved in steady-state. By assuming that some terms are constant, we might get the solution for this problem. By the end of this thesis, we expect to obtain the results based on our objectives using MATLAB simulation. From here, we shall see that either this model is suitable or not to be one of the alternative to overcome the pollution.
Nur Ain Mohamed Ariff
2014-10-09T09:21:45Z
2020-08-18T06:36:27Z
http://eprints.utm.my/id/eprint/id/eprint/42210
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42210
2014-10-09T09:21:45Z
Solidification of floating dispersed organic droplets and ionic liquid microextraction methods for the determination of non-steroidal anti-inflammatory drugs in human urine
Dispersive liquid-liquid microextraction based on solidification of floating organic droplets (DLLME-SFO) and ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) methods coupled with high performance liquid chromatography-ultraviolet detector (HPLC-UV) were developed for the determination of non-steroidal anti-inflammatory drugs (NSAIDs) in human urine samples. Three NSAIDs namely ketoprofen, diclofenac sodium, and mefenamic acid were investigated. In the optimized DLLME-SFO method, a mixture of 1-undecanol (20 µL) as extraction solvent and acetonitrile (100 µL) as disperser solvent was rapidly injected into 5 mL sample solution (pH 2) containing 1% (w/v) NaCl. After 4 min of centrifugation at 5000 rpm, the mixture was separated into two phases with the fine droplets of 1-undecanol floated at the top of sample solution. Then, the test tube was placed in an ice bath for cooling and solidification. The solidified extract was transferred into a small vial where it melts and injected into HPLC-UV system. The DLLME-SFO method gave good linearity over the concentration range from 0.01–10 µg/mL with coefficient of estimation (r2) ranging from 0.9949 – 0.9994. The method also provide low limit of detections (LODs) in the range of 0.0034 – 0.0052 µg/mL. Diclofenac sodium was detected in human urine samples at concentration levels of 1.204 and 0.340 µg/mL after two and four hours of administration. In ILDLLME method, the optimum IL-DLLME parameters was a mixture of 1-butyl-3- methylimidazolium hexafluorophosphate, [BMIM][PF6] (20 µL) as extractionsolvent and acetone (80 µL) as disperser solvent was injected into a 5 mL of sample solution (pH 2), containing 1% (w/v) of NaCl. Then, the sample solution was centrifuged for 4 min at 5000 rpm to settle the extractant. The settled phase was then withdrawn, and diluted with 1:1 ratio of dispersive solvent before injected into the HPLC-UV system. The developed method shows good linearity for the analytes in the range of 0.01 – 10 µg/mL, with coefficient of estimation (r2) in the range of 0.9955 – 0.9974, and low LODs for the analytes in the range of 0.0057 – 0.0088 µg/mL. This method was successfully applied to the determination of diclofenac sodium in human urine samples. The analyte was detected in human urine samples at concentration levels of 1.196 and 0.223 µg/mL after two and four hours of administration. Both methods were applied for intra- and inter-day precision of the target analytes in urine sample at spiking levels of 0.05 and 1.0 µg/mL. The results showed excellent relative recoveries and acceptable RSD were achieved for both DLLME-SFO (95.73 – 115.64%, <9.80%) and IL-DLLME (84.92 – 99.99%, <8.82%), respectively. Based on the results obtained, it could be concluded that the DLLME-SFO method was more efficient and sensitive than IL-DLLME.
Dyia Syaleyana Md. Shukri
2014-10-09T09:21:44Z
2020-08-19T07:40:00Z
http://eprints.utm.my/id/eprint/id/eprint/42232
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42232
2014-10-09T09:21:44Z
Three dimensional surface movement detection using terrestrial laser scanning method
For the past years, numerous conventional and modern surveying methods have been used in landslide studies. Since landslide evolves continuously as a result of natural processes, better and faster tools related to generating more realistic three dimensional (3D) Digital Terrain Model (DTM) representation of the landslide sites are desired. Recently, Terrestrial Laser Scanning (TLS) has been recognized as the most promising remote sensing techniques for geohazard studies. It offers very high resolution of spatial sampling in 3D measurement in a short time and also without contact with the hazardous area. The aim of this study is to evaluate the capability of TLS technology in landslide investigation. Leica ScanStation2 scanner was utilized to obtain 3D cloud points of landslide area at Institut Tanah Ukur Negara (INSTUN), Ulu Behrang, Perak, Malaysia. Several ground control points (GCP) were established for georeferencing purpose using Trimble R8 receiver whereby the local coordinates of the GCP were derived from Malaysian Real Time Kinematik network (MyRTKnet). The commercial software Cyclone 6.0 was used to process the target-based registration and produce DTM. The processing result has shown that the use of three tie-points is very sufficient for registration and georeferencing process which gave the maximum constraint value within 24mm, and about 16mm for Root Mean Square (RMS). The accuracy assessment of DTM comparison gave the standard normal distribution of errors after re-registration process using surface matching method. The landslide investigation was conducted and the displacement detected with range from -0.538m to 0.678m. The overall result of this study shows that TLS is an effective tool in detecting the surface movement of the landslide prone area.
Mohd. Syahmi Akram Mat Zam
2014-10-09T09:21:43Z
2017-07-09T03:45:48Z
http://eprints.utm.my/id/eprint/id/eprint/42109
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42109
2014-10-09T09:21:43Z
Effect of synthesis parameters on structural and morphological properties of nanocrystalline bismuth phosphorus oxide materials
Bismuth phosphorus oxide (BPO) has attracted much attention due to its various applications such as catalysts, photocatalysts, ionic conductors, and metal ion sensors. This material is usually produced via solid state reaction, hydrothermal synthesis, and ball milling which are associated with long reaction time, high synthesis temperature, and microsized products. Thus, an attempt was carried out in this research to synthesize nanocrystalline BPO using a relatively simple hot injection method at low reaction temperature. Bismuth acetate and calcium phosphide were used as precursors of bismuth and phosphorus, respectively. Phosphorus precursor reacted with 4 M hydrochloric acid (HCl) to generate phosphine (PH3) gas which later reacted with bismuth precursor in a mixture of 1-octadecene (ODE) and myristic acid (MA). Several parameters in synthesis condition including reaction temperature, type of reaction solvent, ratio of stabilizer (MA) to reaction solvent (ODE), amount of reaction solvent, reaction time, and ageing time were investigated. X-ray diffraction (XRD) results suggested that single phase BPO material with high crystallinity was obtained at reaction temperature 180°C with reaction time of 30 minutes and ratio of MA:ODE of 1:90. The XRD pattern of this material was best fitted with that of reported Bi3.69P0.31O6.31 (PDF 2010:43-0455), implying formation of face centered cubic (FCC) phase with lattice parameter a = 0.5416 nm. This FCC phase was in good agreement with transmission electron microscopy (TEM) analysis with average lattice fringes spacing of 0.337 nm. As evidenced, TEM and XRD results showed that particle size of the materials were in range of 10 to 20 nm. These materials are interesting as they have an ordered lamellar structure with both large meso and macro pores, indicating the formation of porous structure between the layers of BPO materials. In conclusion, nanocrystalline BPO was successfully synthesized via hot injection method for the first time.
Hartini Khairi Osman
2014-10-09T09:21:43Z
2017-07-09T07:58:05Z
http://eprints.utm.my/id/eprint/id/eprint/42115
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42115
2014-10-09T09:21:43Z
Electrodeposition of titanium, tungsten and zinc layered oxides as photocatalysts for the degradation of benzene-toluene-xylene in aqueous phase
Chien Ju Lee
2014-10-09T09:21:43Z
2020-08-17T02:29:24Z
http://eprints.utm.my/id/eprint/id/eprint/42196
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42196
2014-10-09T09:21:43Z
Preferred housing attributes by participants of Malaysia my second home
The lucrative market of foreign second homers attracts Malaysian developers to target participants of Malaysia My Second Home (MM2H) in their housing projects. However, the inability to satisfy second homers’ preferred housing attributes could lead to the failure of MM2H targeted housing projects for there are differences between second homers’ needs and developers’ offers. There is a need to study the housing preferences of participants in MM2H in order to help developers to deliver better and favourable housing projects for them. The first objective of this study is to characterize housing attributes in the second home market. The second objective is to identify housing attributes preferred by the participants of MM2H. This is then followed with a profiling of the preferred housing attributes by the participants of MM2H from various countries. The research methodology consists of six stages, including a literature review, identification of the data source, a research instrument, data collection, data analysis, validation and recommendations. The questionnnaire survey was conducted among licensed and active MM2H agents. A total of 41 respondents participated in the study. They provided a better overview of MM2H participants’s preferences in selecting their second home. An analysis of frequency and analysis of variance was conducted on the collected data. The findings revealed that housing price and cost of living are the two most important elements in purchasing a second home. The findings also revealed that condominiums, gated and guarded communities, a secure and quality environment, green scenery and a swimming pool are the common features preferred by MM2H participants. Accordingly, Cluster Townhouse is the least favourable design by MM2H participants whereas the condominium is the most favourable. The results obtained were used to profile the MM2H participants’ preferred housing attributes. The profile serves as a good reference for developers in their planning and targeting of buyers in the second home market.
Lay See Lee
2014-10-09T09:21:42Z
2020-07-27T03:44:17Z
http://eprints.utm.my/id/eprint/id/eprint/42054
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42054
2014-10-09T09:21:42Z
A hybrid Box-Jenkins and decomposition model drought forecasting in Kuala Terengganu
Drought is a global phenomenon which adversely affects the sustainability of one nation which encompasses three prominent aspects such as economic, social and environmental. Due to that, it has immensely attracted the awareness of environmentalists, ecologists, hydrologists, meteorologists, geologists and agricultural scientists. Therefore, drought forecasting is essential for several key players particularly the governments to evaluate the drought occurrence in order to give early warning for preparedness and mitigation measures. In this study, a hybrid Box-Jenkins and decomposition model based on standardized precipitation index (SPI) was developed to forecast drought in Kuala Terengganu. Monthly rainfall data of rain gauge station, Setor JPS Kuala Terengganu for period January 1982 to January 2012 was used in this study. Multiplicative decomposition method was employed to identify and isolate the underlying components of SPI time series for multiple time scales using Minitab 16.0. Then the isolated components were gone through the four-step iterative procedure of Box-Jenkins which are identification, estimation, diagnostic checking and forecasting. After that, the forecasted values of components were reassembled in order to gain a forecast based on the time series decomposition. The forecasting performance of the hybrid model was compared with the Box-Jenkins model. Two statistical measurements, mean absolute error (MAE) and mean squared error (MSE) were applied in this study to measure the accuracy of the forecasting models. In brief, the accuracy measure results indicated that the hybrid model can prevail over the Box-Jenkins model.
Mee Chyong Ho
2014-10-09T09:21:40Z
2020-08-05T02:06:10Z
http://eprints.utm.my/id/eprint/id/eprint/42112
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42112
2014-10-09T09:21:40Z
Electricity load forecasting using hybrid of multiplicative double seasonal exponential smoothing model with artificial neural network
Electricity load forecasting often has many properties such as the nonlinearity, double seasonal cycles, and others those may be obstacles for accurate forecasting using some classical statistical models. Many papers in this field have proposed using double seasonal (DS) exponential smoothing model to forecast. These were found that electricity load forecasting using DS exponential smoothing model will be fitted, since this model studies the double seasonal effects those are in the studied data. Using artificial neural network (ANN) as a modern approach may also enable for more fitted forecasting, since this approach can deal with the non-linearity components of load data .The purpose of this study is improving the electricity load forecasting by building the hybrid model which includes a double seasonal exponential smoothing with an artificial neural network .This hybrid model will be studied the double seasonal effects and non-linearity components together those are in the electricity load data .The strategy of building this hybrid model is by entering ANN output as an input in double seasonal exponential smoothing model. The data sets are taken from three stations with different electricity load characteristics such as a residential, industrial, and the city center .The electricity load testing forecast of DS exponential smoothing-ANN hybrid gave the most minimum mean absolute percentage error (MAPE) measurement comparing with the electricity load testing forecasts of DS exponential smoothing and ANN for all electricity load data sets. In conclusion, DS exponential smoothing-ANN hybrid model are the most fitted for every electricity load data which contains the double seasonal effects and non-linearity components.
Naam Salem Fadhil
2014-10-09T09:21:40Z
2014-10-09T09:21:40Z
http://eprints.utm.my/id/eprint/id/eprint/42126
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42126
2014-10-09T09:21:40Z
First principle DFT calculation for structural and electronic properties of magnesium indium sulphide and cadmium indium sulphide
Saddiq Abubakar Dalhatu
2014-10-09T09:21:39Z
2017-07-06T06:49:25Z
http://eprints.utm.my/id/eprint/id/eprint/42100
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42100
2014-10-09T09:21:39Z
Documentation of Seri Menanti palace using three-dimensional phase shift terrestrial laser scanner
Generally, traditional documentation methods are time consuming, having limitation in collecting information and not able to provide re-visit of a historical building to present the artwork and design by the craftsman. The modern Geoinformation technology, laser scanning was used in this research and proven its effectiveness to record spatial data of Seri Menanti Palace, located in Negeri Sembilan, which was fully built by timber. The main goal of this research was to to digitally preserve and document heritage building by produce three-dimensional (3D) model of the historical building mentioned above with Level of Details 4 (LoD 4) as prescribed by CityGML. FARO Photon 120 laser scanner was integrated with high resolution Nikon DSLR D300s digital camera to collect 3D point clouds data and panoramic coloured image in full angular of 360°. A total of 165 scanning stations were required in data collection process which involves 120 stations for the interior and 45 stations for the exterior part of the palace. The collected point clouds data were registered by using the surveyed target and natural feature on the palace. The registered 3D point clouds that were geo-referenced with Cassini coordinate system and were integrated with panoramic images to produce 3D colourized point clouds which later rendered as animation aspect for “Fly Through” presentation purpose. Besides animation, this research also produce 3D surface model and floor plan of the palace. Several 3D measurements were taken from the generated 3D model and being compared with the measurement performed by the conventional method. Generally, this research had successfully proven that TLS technology can be used to record the palace data that built from timber. However, several parts of the palace cannot be recorded perfectly due to the cause of dark facade and the tall rooftop also is the limitation of the laser scanner used
Siew Chin Cheong
2014-10-09T09:21:37Z
2017-07-19T07:21:16Z
http://eprints.utm.my/id/eprint/id/eprint/42183
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42183
2014-10-09T09:21:37Z
Pemetaan zon tanah runtuh kawasan Bukit Antarabangsa menggunakan ARCGIS 9.3 dan model stability index mapping
The geohazard stability assessment is very important for the prediction and management of natural disaster such as landslide, flood, earthquake and so on. For example, the analysis of landslide requires evaluation of the relationship between various terrain conditions and landslide occurrences. The aims of this study are to produce and to analyze a landslide susceptibility map for hillsite areas at Bukit Antarabangsa, Ulu Klang, Selangor. The relationship between landslide distributions and layer parameters such as slope gradient, rainfall, drainage, geology and land use have been prepared, recorded and processed in Geographical Information System (GIS) database environment. Next, the numerical weights for all factors were determined using weighted overlay method. The ArcGIS Ver 9.3 software was used to execute, manage, display and analyse spatial data for production of landslide susceptibility map at scale of 1:8 000. Weighting and ranking of causative factors to landslide occurrence have been used to predict landslide potential areas. In this study, the landslide susceptibility map was divided into four zones of stability index values: Low (0-1), Moderate (2-3), Moderate High (4-5) and High (6-8). The ranges of classification were derived from the histogram of assessment of landslide stability. Many locations of landslide occurrence are located in the moderate high and high index. The results of the soil stability map of an area of approximately 1 km2 showed that only 0.8% of the study area lies in the highest landslide prone area. Similarly, 23.4%, 70% and 5.8% of the area lies in the moderate high, moderate and low landslide prone area respectively. This susceptibility map is compared with the landslide map derived from Stability Index Mapping (SINMAP) model. In general, this study found that Bukit Antarabangsa area posed a relatively high percentage of landslides occurrence with slope angle larger than 20 degrees. Daily rainfall more than 50mm becomes a triggering factor to a landslide event at Bukit Antarabangsa and the area nearby.
Siti Suaibah Abdul Rahim
2014-10-08T07:32:38Z
2014-10-08T07:32:38Z
http://eprints.utm.my/id/eprint/id/eprint/41847
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41847
2014-10-08T07:32:38Z
Free vibration of angle-ply laminated cylindrical shells using chebyshev polynomials
Amirah Haziqah Zulkifli
2014-10-08T07:32:38Z
2020-07-27T00:39:45Z
http://eprints.utm.my/id/eprint/id/eprint/42018
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42018
2014-10-08T07:32:38Z
The effect of Nd : YAG laser beam on aluminium surface coated with Fe-SiC
Laser ablation on aluminium base coated with Fe-SiC is reported. A qswitched Nd:YAG laser was employed as a source of energy. The fundamental wavelength of the laser beam is 1064 nm with output energy of 100 mJ and pulse duration of 10 ns. The laser was conducted in repetitive mode with frequency rate of 1 Hz. The laser was focused to induce plasma formation. Pure aluminium plate was employed as a substrate for laser ablation. Metal element iron (Fe) and ceramic material silicon carbide SiC were selected to be as laser ablation elements. Both of the elements were mixed together in a ratio of 2:1 (Fe:SiC). Two step deposition techniques were chosen in this work to predeposite the aluminium substrate. The substrate was painted with cohesive material gum before powder spray coating on it. The predeposit aluminium was then exposed with focused laser at various numbers of pulses (1 – 13 pulses). The created material was examined via scanning electron microscope (SEM), x-ray diffraction (XRD) machine and microhardness Vicker HV machine. The microstructure of the created surface was examined via SEM and the results showed the effect of homogenized resolidified area. The plasma temperature is much higher than the melting point of the laser ablation material Fe and SiC thus immediately after plasma interaction with coating materials most of them are melted. The fluid flow over the surface and resolidified during cooling. However the melting temperature between Fe, SiC and Al are different, this allows new composite formation during quenching. The formation of such new composite is identified through XRD analysis. Inherently, several new composites are revealed such as Al- Fe-Si, SiAl and Fe-Si. The formation of such new composite is also indicators for the increment in the strength of the created materials. This is validated by measuring the hardness of the created material. Apparently, the hardness of the modified surface is confirmed to be two times greater than the original substrate.
Asad A. Thahe
2014-10-08T07:32:35Z
2020-07-05T03:15:07Z
http://eprints.utm.my/id/eprint/id/eprint/41799
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41799
2014-10-08T07:32:35Z
Catalytic oxidative desulfurization of diesel fuel utilizing monometallic, bimetallic and trimetallic oxides doped on molybdena supported alumina
Existing technique of hydrodesulfurization (HDS) is no longer applicable in achieving Euro IV standard diesel due to the high operational cost, low efficiency and high operating temperature in hydrogen gas atmosphere. Due to these drawbacks, the utilization of the catalytic oxidative desulfurization (CODS) was introduced to complement the HDS process. In this study, the performance of the activated carbon supported cerium and iron catalysts were investigated using tertbutyl hydroperoxide (TBHP) as an oxidizing agent and N,N-dimethylformamide (DMF) extraction solvent. The effect of dopant ratio, calcination temperature, number of loading and CODS treatments were studied. The results showed that effective dopant ratio of Ce/Fe (80:20) prepared by wet impregnation method calcined at 400°C was the best catalyst. X-ray diffraction analysis (XRD) results showed that the catalyst is amorphous, while micrograph of the field emission scanning electron microscopy (FESEM) illustrated an inhomogeneous distribution of various particle sizes composed of cerium and iron oxides as been proven by energy dispersive X-ray analysis (EDX) on the surface of prepared bimetallic catalyst. Nitrogen adsorption/desorption measurement showed the characteristic of microporous structure with Type 1 IUPAC isotherm. The deep desulfurization of Malaysian commercial diesel fuel contained 440 ppm sulfur was achieved after oxidation with two cycle extraction process with 98% total sulfur removal to produce Green Diesel contained 8.8 ppm sulfur has been measured using GC-FPD. The results obtained has proven that CeO2/Fe2O3 (80:20)-AC can be used as potential catalyst for the removal of sulfur in the Malaysian diesel towards achieving the green diesel production.
Nur Atiqah Nasir
2014-10-08T07:32:35Z
2020-07-05T03:34:40Z
http://eprints.utm.my/id/eprint/id/eprint/41803
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41803
2014-10-08T07:32:35Z
Chemical constituents and bioactivity studies on Premna integrifolia Linn
Premna integrifolia known as buas-buas in Malaysia is one of the species of Verbenaceae family. Extraction, fractionation followed by purification of P. integrifolia afforded seven compounds which consisted of flavone, quinone, ester, plant sterols and diterpene. The structures were elucidated using spectroscopic methods including nuclear magnetic resonance (NMR), mass spectrometry (MS), infrared (IR), and ultraviolet (UV) spectroscopies. Two flavones identified as 5,7-dihydroxy-4'-methoxyflavone and 4',5,7-trihydroxyflavone were isolated from the leaves, while two new compounds named integrifolinone and icetexane-X, together with a mixture of two plant sterols, stigmasta-5,22-dien-3ß-ol and stigmasta-5-en-3ß-ol were obtained from the roots. In addition, an ester 2-(4'-hydroxyphenyl)ethyl dodecanoate was isolated from the barks. Antioxidant screening was carried out on the crude extracts and pure compounds. The ethyl acetate extract of the leaves and hexane extract of the roots were found to have low antioxidant activity, while the pure compound icetexane-X gave the most active radical scavenger, with an SC50 of 30.79 µg/mL compared to vitamin C which showed an SC50 of 12.71 µg/mL. In the antimicrobial assay, all the crude extracts and pure compounds were found to be inactive towards all the tested bacteria (Staphylococus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa)
Kamarusalihin Nordin
2014-10-08T07:32:35Z
2014-10-08T07:32:35Z
http://eprints.utm.my/id/eprint/id/eprint/41849
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41849
2014-10-08T07:32:35Z
Free vibrations of laminated symmetric angle-ply annular circular plates using spline function
Farah Syazwani Mohd. Shukri
2014-10-08T07:32:34Z
2014-10-08T07:32:34Z
http://eprints.utm.my/id/eprint/id/eprint/41918
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41918
2014-10-08T07:32:34Z
Niobium-phosphate impregnated silica-titania as oxidative-acidic bifunctional catalyst in synthesis of diols
Jamilah Mohd. Ekhsan
2014-10-08T07:32:34Z
2020-07-26T08:04:16Z
http://eprints.utm.my/id/eprint/id/eprint/42011
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42011
2014-10-08T07:32:34Z
Ternary semiconductor photocatalysts for the degradation of benzene-toluene-xylene in aqueous phase
Wastewater produced from the petroleum industry contains hazardous organic compounds such as benzene, toluene and xylene (BTX). A method based on advanced oxidation process has been applied to treat the organic compounds using semiconductor photocatalysts. Three types of ternary photocatalysts,namely ZnO/WO3/SnO2(ZWS), ZnO/WO3/Fe2O3(ZWF) andZnO/WO3/TiO2(ZWT) were prepared viamodified sol-gel method with different percentage ofatomic ratios of each metal oxide. Characterization of the catalyst was conducted using X-ray diffraction (XRD), diffuse reflectance ultra-violetspectroscopy (DR-UV), field emission scanning electron microscopy-energy dispersive X-ray (FESEM-EDX) and nitrogen adsorptionanalyses. The XRD analysis revealed that all the prepared catalysts are mostlyin polycrystalline phases. The existence of binary species such as ZnWO4, SnW3O9 and Fe2WO6 were detected in the bulk matrices of the ternary oxide catalysts. The types of physisorption isotherm represented by ZWS (90:9:1), ZWS (90:3:7), ZWS (33:33:34) and ZWT (33:33:34) photocatalysts were of the Type IV isotherm and hysteresis loop assigned for the mesoporousity of the respective catalysts. The band gap energy of each photocatalyst was determined by DR-UV and it showedthat the band gap was affected by the change in ratio of the precursors. FESEM-EDX analysis for all the prepared ternary catalysts exhibited small and dispersed particles. The photocatalytic activity of the prepared ternary catalysts was tested on thesimulated BTX aqueous phase (1000 ppm)irradiated under UV-light. ZWSwith the ratio of 90:3:7, 7:3:90 and 1:90:9gave 66.97%, 59.02% and 61.01% of the BTX degradation, respectively. Meanwhile, ZWF (33:33:34), ZWS (33:33:34), and ZWT (33:33:34)photocatalysts gave43.27%,68.58%, and 70.41% of the BTX degradation, respectively. All the degradation processes were conducted using365 nm UV-light at ambient temperature and pressure. The total organic carbon (TOC) analysis revealed that the percentageof mineralization of the treated compounds were 40.58% (ZWF33:33:34), 64.91% (ZWS33:33:34), and 65.36% (ZWS33:33:34) with slightly increased in the percentage of degradation using 312 nm light source. The optimum concentration of H2O2used was 10 ppmwith72.32% of BTX degradation using ZWTphotocatalystand365 nm UV-light source. The reproducibility study usingZWTcatalyst immobilized on quartz glass showed that the photocatalyticactivity decreased gradually after the first usage
Zul Adlan Mohd. Hir
2014-10-08T07:32:33Z
2017-07-16T07:31:18Z
http://eprints.utm.my/id/eprint/id/eprint/41794
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41794
2014-10-08T07:32:33Z
Biosynthesis of Au, Ag and bimetallic Au-Ag nanoparticles using aqueous leaf extract of cosmos caudatus
There is great interest in synthesizing metal nanoparticles due to their remarkable application in medicinal, catalysis and electronic. Single step biosynthetic approaches utilising plant extracts have emerged as a simple, ecofriendly and viable alternative to chemical synthetic procedures and physical methods. In the present study, we have synthesized mono- and bimetallic gold and silver nanoparticles by reduction of Au3+ and Ag+ ions using aqueous leaf extract of Cosmos caudatus (ulam raja). The formation of the Au and Ag nanoparticles was monitored using UV-Vis spectroscopy and was visually confirmed by colour change from yellowish to violet and from colourless to dark brown, respectively. The surface plasmon resonance (SPR) band appeared at 536 nm and 439 nm for Au and Ag, respectively. Meanwhile, competitive simultaneous reduction of Au3+ and Ag+ ions present in same solution led to the production of bimetallic Au-Ag in which the SPR band appeared at 533 nm. The nanoparticles were also characterised by using TEM, FESEM-EDX, XRD and FTIR analyses. FESEM micrographic images show the spherical shape for both gold and silver nanoparticles with average particle size 22.79 ± 6.81 and 21.49 ± 7.43, respectively. TEM images of the bimetallic Au-Ag nanoparticles showed the spherical shape of nanoparticles with average particles size of 13.98 ± 6.21 nm. Profile EDX spectra show the signals for both Au and Ag in the sample of AuNPs and AgNPs, respectively. Both signals appear for bimetallic sample, indicating that the bimetallic Au-Ag was in alloy form. X-ray diffraction (XRD) analysis revealed that the mono- and bimetallic nanoparticles were face centered cubic (fcc) in structure. FTIR spectra of the nanoparticles showed main absorptions at 3364.81 cm-1(-OH stretching vibrations), 2925.49 cm-1 (asymmetric stretching of C-H groups), 1650.59 cm-1(stretching vibrations C=O (amide and aldehyde), 1384.67 cm-1 (C-N stretching vibrations of amines) and 1067.62 cm-1(COH stretching of secondary alcohols) indicating the nanoparticles are capped with the bioactive compounds present in the plant extract.
Rapidah Mohamad
2014-10-08T07:32:31Z
2014-10-08T07:32:31Z
http://eprints.utm.my/id/eprint/id/eprint/42020
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42020
2014-10-08T07:32:31Z
The effects of plant growth regulators and amino acids on the germination of Melastoma Malabathricum L. through tissue culture
Khoirun Nisa Mahmud
2014-10-08T07:32:30Z
2014-10-08T07:32:30Z
http://eprints.utm.my/id/eprint/id/eprint/41925
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41925
2014-10-08T07:32:30Z
Optimal control model and solution of seasonal production and inventory problem
Nur Shazrahanim Kamar
2014-10-08T07:32:28Z
2014-10-08T07:32:28Z
http://eprints.utm.my/id/eprint/id/eprint/41995
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41995
2014-10-08T07:32:28Z
Structural analysis and modeling comparison of primates' amyloid BA4 protein
Fahimeh Jalali 1987-
2014-10-08T07:32:28Z
2014-10-08T07:32:28Z
http://eprints.utm.my/id/eprint/id/eprint/42013
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/42013
2014-10-08T07:32:28Z
The application of meshless Element Free Galerkin (EFG) method in Burgers' Equation
Iylia Haniza Ismail
2014-10-08T07:32:27Z
2020-07-05T01:31:58Z
http://eprints.utm.my/id/eprint/id/eprint/41789
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41789
2014-10-08T07:32:27Z
Applications of game theory in bankruptcy game
Bankruptcy is a problem that can happen to anybody. It occurs when the total amount of debt to be paid is larger than the total amount of asset. The question is how to divide the asset to different creditors fairly. The main objective of this thesis was to solve the remaining asset division for a company that went bankrupt. There were three methods being used to solve the division of the asset and the methods were Talmud division, Shapley value and the Nucleolus. By using 3-agents and 4-agents cooperative games, we compared all three methods to determine which methods are favourable to the creditors.
Hanisah Haidzir
2014-10-08T02:21:02Z
2017-06-22T01:15:59Z
http://eprints.utm.my/id/eprint/id/eprint/41672
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41672
2014-10-08T02:21:02Z
Laplace transform and adomian decomposition methods for solving nonlinear volterra integro-differential equations
Since its introduction in the 1980s, the Adomian Decomposition Method (ADM) has proven to be an efficient and reliable method for solving many types of problems. Originally developed to solve nonlinear functional equations, the ADM has since been used for a wide range of equation types (like boundary value problems, integral equations, equations arising in flow of incompressible and compressible fluids etc...). This work is devoted to an evaluation of the effectiveness of this method when used for solve nonlinear Volterra integro-differential equations and also the combined form of the Laplace transform method with the Adomian decomposition method is effectively and useful way to develop an analytic treatment for many types of equations, linear and nonlinear ordinary differential equations (ODE), linear and nonlinear partial differential equations (PDE). In this study will combined Laplace transform-Adomian decomposition method to solve nonlinear Volterra integro-differential equations, this study is divided into five Chapters. The first chapter is devoted to an introduction, the second is devoted to the literature review, and Chapter 3 devoted to research methodology, Chapter 4 presents the solution for the nonlinear Volterra integro-differential equation. Finally, the Chapter 5 is devoted to the conclusion and recommendations based on this study.
Zahra Vafaeifar
2014-10-08T02:20:58Z
2014-10-08T02:20:58Z
http://eprints.utm.my/id/eprint/id/eprint/41714
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41714
2014-10-08T02:20:58Z
Recovery of Cr(lll) from Cr(Vl) reduction system using Acinetobacter haemolyticus & synthesis of Cr(lll) propionate complex
Riyadh Zainadin Mawlood
2014-10-08T02:20:55Z
2017-06-20T08:18:54Z
http://eprints.utm.my/id/eprint/id/eprint/41675
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41675
2014-10-08T02:20:55Z
Mathematical modeling of blood flow through an eccentric catheterized artery
The mathematical model of blood flow through a catheterized stenosed artery is considered. A catheter is a tube, which is used in medicine for patients who are bedridden and whose blood pressure needs to be measured and monitored continuously. An example is the use of catheter during X-ray angiography or coronary balloon angioplasty in cardiac patients. Inserting a catheter in an artery will alter some characteristics of blood flow. This project investigates the effect on blood flow characteristics such as the velocity, the wall shear stress, the resistance impedance and the streamlines when a catheter is inserted into a stenosed artery. The catheter and the artery are assumed to be in a co-axial and eccentric position while blood is assumed to be Newtonian. The governing Navier-Stokes equations are solved analytically using perturbation method. The results show that a catheter placed in an eccentric position does alter the blood flow characteristics such that the axial velocity and the wall shear stress distribution are higher while the resistance impedance values are lower compared to their values in an artery where the catheter is concentrically placed. It is also found that under the same situation, the position of trapping moves closer to the wall of the stenosis while the size of the trapped bolus increases.
Sima Sarv Ahrabi
2014-10-02T05:35:55Z
2014-10-02T05:35:55Z
http://eprints.utm.my/id/eprint/id/eprint/41201
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41201
2014-10-02T05:35:55Z
Ortho-cresolas as indicator for toluene exposure among workers
Nazirah Said
2014-10-02T05:35:54Z
2014-10-02T05:35:54Z
http://eprints.utm.my/id/eprint/id/eprint/41200
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41200
2014-10-02T05:35:54Z
Optical properties and photoluminescence of copper nitride thin film prepared by reactive dc sputtering
Noor Azizun Mohammed Ariff
2014-10-02T05:35:54Z
2014-10-02T05:35:54Z
http://eprints.utm.my/id/eprint/id/eprint/41204
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41204
2014-10-02T05:35:54Z
Removal of heavy metals from crude oils using complexing agents and ionic liquids
Alyaa Amalina Mohd. Azli
2014-10-02T05:35:53Z
2014-10-02T05:35:53Z
http://eprints.utm.my/id/eprint/id/eprint/41203
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41203
2014-10-02T05:35:53Z
Properties of 4-fluoro benzoic acid modified zinc oxide nanoparticles by sol-gel method
Hozan Salahuddin Ahmed
2014-08-20T08:19:23Z
2017-02-15T06:50:39Z
http://eprints.utm.my/id/eprint/id/eprint/41042
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41042
2014-08-20T08:19:23Z
Radiological information of Kelantan - a review
This study reviewed radiological research works conducted in the state of Kelantan, Peninsular Malaysia. A total number of eleven research articles available to the authors were reviewed and reported accordingly in this paper. From the studies it was observed that not much has been done in revealing the radiological state of the region despite been blessed with abundant granitic rock deposit. Some of the papers reviewed reported the presence of high activity concentration of naturally occurring radionuclides i.e. 238U, 232Th, 226Ra, 228Ra, 222Rn, and 40K in some study areas like work of (Siti Afiqah et al, 2012; Mohammed Kasim et al, 2011 etc.) while few studies were reported to be below the global and Malaysian average as can be seen in the text
Nuraddeen Nasiru Garba
Ahmad Termizi Ramli
Hamman Tukur Gabdo
M. S. Sanusi
2014-08-20T08:19:22Z
2017-08-22T07:52:18Z
http://eprints.utm.my/id/eprint/id/eprint/40948
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40948
2014-08-20T08:19:22Z
On the sensitivity of poisson EWMA control chart
Until recently, the application of the runs rules was restricted to the Shewhart-type control charts. In this paper, we propose an EWMA control chart with fast initial response (FIR) using ?? ??/ runs rule scheme for monitoring Poisson observations. Using Monte Carlo simulations, we studied and compared the average run length (ARL), the Average Ratio ARL (ARARL), the Average Extra Quadratic Loss (AEQL) and the Performance Comparison Index (PCI) of the proposed runs rule FIR Poisson EWMA chart with some other Poisson EWMA procedures. It is shown that the use of runs rule and FIR feature has substantially increased the sensitivity of Poisson EWMA control chart without decreasing the out-of-control ARL. The proposed chart is more effective in detecting moderate shifts in Poisson process than some of the existing procedures.
Mu’azu Ramat Abujiya
Abbas Umar Farouk
Muhammad Hisyam Lee
Ismail Mohamad
2014-08-20T08:19:17Z
2017-02-15T06:41:12Z
http://eprints.utm.my/id/eprint/id/eprint/40933
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40933
2014-08-20T08:19:17Z
Multivariate outlier detection in currency exchange rate
In correlation networks analysis, the influential currencies is usually identified by using minimal spanning tree (MST) to filter the important information followed by the centrality measures analysis. In this paper, we introduce an analysis to identify the currencies that might have different behaviour compared to the others which is also conducted based on MST by using outlier labelling and testing. A case study on 78 currency exchange rate will be reported and discussed.
Shamshuritawati Sharif
Maman Abdurachman Djauhar
Nur Syahidah Yusoffi
2014-08-20T08:19:16Z
2017-08-22T07:46:45Z
http://eprints.utm.my/id/eprint/id/eprint/40946
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40946
2014-08-20T08:19:16Z
On properties of the graph of fuzzy topographic topological mapping
Fuzzy Topographic Topological Mapping (FTTM) is a novel noninvasive technique to determine the location of epileptic foci in epilepsy disorder patients. The model which consists of topological and fuzzy structure is composed into three mathematical algorithms. There are two FTTMs, namely FTTM Version 1 and FTTM Version 2. FTTM Version 1 is homeomorphic to FTTM Version 2. The homeomorphism of FTTM can be presented using graphs. This paper presents some properties of the graph of FTTM.
Mohamed Sayed
Tahir Ahmad
2014-08-20T08:19:16Z
2017-08-22T07:49:34Z
http://eprints.utm.my/id/eprint/id/eprint/40947
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40947
2014-08-20T08:19:16Z
On the hurdle negative binomial regression model with excess zeros for a right truncated count data
A Poisson regression model is well-known for modeling the data with response variable in form of counts. However, one often encounters the situation with excess zeros occurred in the observed responses. Therefore, Poisson model is not suitable any more for this kind of data. Thus, we propose to use a hurdle negative binomial model. Furthermore, the response variable in such cases is truncated for some values. So, a truncated hurdle negative binomial model is introduced on count data with many zeros. In this model, we consider a response variable and one or more than one explanatory variables. The estimates using the maximum likelihood method are discussed and the goodness-of-fit for the regression model is examined. We study the effects of right truncation in terms of parameters estimation and their standard errors via an example and a simulation.
Seyed Ehsan Saffari
Xiaojian Xu
Robiah Adnan
Adeleh Hashemi Fard
2014-08-20T08:19:16Z
2017-08-27T01:08:01Z
http://eprints.utm.my/id/eprint/id/eprint/41026
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41026
2014-08-20T08:19:16Z
Production and characterization of crude and encapsulated prodigiosin pigment
Pigments from microorganisms can serve as an alternative source to replace synthetic pigments used in various industries. Natural pigments have some limitations including solubility, sensitivity and short stability upon exposure to light, pH and high temperature. Thus, employing methods such as encapsulating can be a good alternative to enhance the pigment’s properties. The present work is a comparison of encapsulated and nonencapsulated (crude) prodigiosin extracted from Serratia marcescens in terms of stability and solubility. The results show that the pigment is more stable and soluble in water in encapsulated form when stored in the absence of light and thus has superior stability compared to pigment in its crude form. The results suggest that the encapsulated prodigiosin can be a more stable pigment under the above optimum conditions.
Shahla Namazkar
Rahul Garg
Wan Azlina Ahmad
Nordiana Nordin
2014-08-20T08:19:15Z
2017-08-27T01:15:55Z
http://eprints.utm.my/id/eprint/id/eprint/41028
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/41028
2014-08-20T08:19:15Z
Production of sugarcane bagasse-based activated carbon for cd2+ removal using factorial design
An evaluation of the effect of preparation conditions on the production of activated carbon from sugarcane bagasse for Cd2+ removal was carried out using a 2-level full factorial design. Sugarcane bagasse based activated carbon was prepared in a single step steam pyrolysis using a horizontal tube furnace. The investigated parameters were temperature (700 - 800oC), time (60 - 120 minutes) and steam flow rate (10 - 50 mL/min), within 11 experimental runs. Two responses were considered, the activated carbon yield and the removal % of Cd2+ from aqueous solution. The predicted results from the full factorial model were compared with the experimental values, with regression coefficients of R2 = 0.986 for yield and R2 = 0.989 for removal. Optimization was applied using desirability function with the selected optimum desirability of 0.592 for the set goals.
Musa Mutah
Kikuchi Akira
Zaiton Abdul Majid
Jaafar Jafariah
Salim Mohd. Razman
Ismail Nor Eman
2014-08-20T08:15:16Z
2017-08-16T08:17:51Z
http://eprints.utm.my/id/eprint/id/eprint/40887
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40887
2014-08-20T08:15:16Z
Verification of forecast rainfall anomalies
Statistical downscaling is used to relate the large scale climate information with the local variables that is to find the relationship between the National Center of Environmental Prediction (NCEP) data with the ground data. This study examines the verification of forecast rainfall anomalies during November-December-January-February (NDJF). The ground data used is the 30 years NDJF rainfall for 40 stations while the NCEP data is the 20 grids point Sea Level Pressure (SLP). In this paper, Canonical correlation analysis (CCA) is used to find the maximum correlated pattern between two variables. CCA model is verified using the mean square error skill score and anomaly correlation coefficient and used to simulate the current rainfall using the General Circulation Model (GCM) data as predictors. This is so called the validation method. Due to appearance of some biases, the anomaly correlation coefficient is considerably higher than the skill score. These biases may relate to the penalty associated with retaining the Sea Level Pressure (SLP) in the meteorological features when such features are not predictable.
Kim Kho Pui
Fadhilah Yusof
Zalina Mohd. Daud
2014-08-20T08:15:13Z
2017-08-16T08:12:33Z
http://eprints.utm.my/id/eprint/id/eprint/40885
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40885
2014-08-20T08:15:13Z
Streamflow forecasting at ungauged sites using multiple linear regression
Developing reliable estimates of streamflow prediction are crucial for water resources management and flood forecasting purposes. The objectives of this study are to identifying which the physiographical and hydrological characteristics affected in multiple linear regressions (MLR) model to estimated flood quantile at ungauged site. MLR model is applied to 70 catchments located in the province of Peninsular Malaysia. Three quantitative standard statistical indices such as mean absolute error (MAE), root mean square error (RMSE) and Nash-Sutcliffe coefficient of efficiency (CE) are employed to validate models. MLR model are built separately to estimate flood quantile for T=10 years and T=100 years. The results indicate that elevation, longest drainage path and slope were the best input for MLR model.
Basri Badyalina
Ani Shabri
2014-08-20T08:15:13Z
2017-08-16T08:15:20Z
http://eprints.utm.my/id/eprint/id/eprint/40886
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40886
2014-08-20T08:15:13Z
Time series forecasting using wavelet-least squares support vector machines and wavelet regression models for monthly stream flow data
This paper presents a review of runoff forecasting method based on hydrological time series data mining. Researchers are developed models for runoff forecasting using the data mining tools and techniques like regression analysis, clustering, artificial neural network (ANN), and support vector machine (SVM), Genetic Algorithms (GA), fuzzy logic and rough set theories. The scientific community has been trying to find out a better approach to solve the issues of flood problems. Time Series Data mining is paying crucial role for the achieving a real time hydrological forecast. Hydrological Time series is an important class of temporal data objects and it can be find out from water resource management and metrological department. A hydrological time series is a collection of observations of hydro and hydrometeorological parameters chronologically. The wide use of hydrological time series data has initiated a great deal of research and development attempts in the field of data mining. Trend, pattern, simulation, similarity measures indexing, segmentation, visualization and prediction carried out by the researchers with the implicit mining from the historical observed data. The critical reviews of the existing hydrological parameter prediction research are briefly explored to identify the present circumstances in hydrological fields and its concerned issues.
Siraj Muhammed Pandhiani
Ani Shabri
2014-08-20T08:15:13Z
2017-08-17T06:37:04Z
http://eprints.utm.my/id/eprint/id/eprint/40893
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40893
2014-08-20T08:15:13Z
Stokes' second problem for magnetohydrodynamics flow in a burgers' fluid: the cases ?= ?2/4 and ?> ?2/4
The present work is concerned with exact solutions of Stokes second problem for magnetohydrodynamics (MHD) flow of a Burgers' fluid. The fluid over a flat plate is assumed to be electrically conducting in the presence of a uniform magnetic field applied in outward transverse direction to the flow. The equations governing the flow are modeled and then solved using the Laplace transform technique. The expressions of velocity field and tangential stress are developed when the relaxation time satisfies the condition ??=??2/4 or ?>?2/4. The obtained closed form solutions are presented in the form of simple or multiple integrals in terms of Bessel functions and terms with only Bessel functions. The numerical integration is performed and the graphical results are displayed for the involved flow parameters. It is found that the velocity decreases whereas the shear stress increases when the Hartmann number is increased. The solutions corresponding to the Stokes' first problem for hydrodynamic Burgers' fluids are obtained as limiting cases of the present solutions. Similar solutions for Stokes' second problem of hydrodynamic Burgers' fluids and those for Newtonian and Oldroyd-B fluids can also be obtained as limiting cases of these solutions.
Ilyas Khan
Farhad Ali
Sharidan Shafie
2014-08-20T08:15:11Z
2017-08-17T06:19:39Z
http://eprints.utm.my/id/eprint/id/eprint/40890
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40890
2014-08-20T08:15:11Z
Studies of pg9/2+ isomers in odd 67-79 as nuclei by deep-inelastic collisions
In this paper, we report systematic studies of single particle pg9/2 + isomers in odd 67- 79As nuclei. We have calculated the energies of projectile-like fragments of odd 67- 79As in 76Ge (635 MeV) + 198Pt reactions. The theoretical calculations of projectile like fragments (PLFs) energies are compared with the experimental values. The mean lives, reduced transition probabilities, width of isomeric levels, and Weisskopf hindrance factors in odd 67-79As nuclei are calculated. The excitation levels of 9/2+ and 5/2- state as a function of mass number from odd 67As to 79As nuclei indicate maximum deformation at N=42. The systematic reduced transition probabilities B(M2) of odd 67-79As nuclei are also investigated. The angular distributions of fragments energies of 79As and its counterpart as a function of scattering angles are investigated.
Hossain Hossain
N. N. A. M. A. Ghani
Mohammad Alam Saeed
H. Y. Abdullah
K. K. Viswanathan
H. Wagiran
2014-08-20T08:15:09Z
2017-08-20T00:37:09Z
http://eprints.utm.my/id/eprint/id/eprint/40897
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40897
2014-08-20T08:15:09Z
The impact of Ash3 overflow time and indium composition on the formation of self-assembled Inxga1 - Xas quantum dots studied by atomic force microscopy
We have performed atomic force microscopy to investigate the effect of various indium compositions and various AsH3 flow times during cooling on the formation of self-assembled InxGa1 xAs quantum dots (QDs). The InxGa1 xAs QDs were grown by metal-organic chemical vapour deposition using the Stranski-Krastanow (S-K) growth mode. The migration of group III species in the growth of InxGa1 xAs QDs is influenced by the AsH3 flow during the cooling period due to the increasing surface population of the active arsenic species. It influences the size and density of the dots on the surface. For various indium compositions, an increase in InxGa1 xAs QD density with increasing indium composition is observed. It indicates that the dot density depends on lattice parameters. The dot density is inversely proportional to surface diffusion (rho [proportional to] R/D), with D = (2kT/h)/a2 exp(ED/kT). In the growth of InxGa1 xAs QDs using the S-K growth mode, the dots were formed on the surface as the effect of elastic strain relaxation due to the lattice mismatch. Increasing indium composition affects the lattice mismatch of the InxGa1 xAs/GaAs QD system, which influences the dot formation on the surface. However, due to the stochastic nature of the nucleation of self-assembled growth, control of the spatial ordering of the QDs has proved to be extremely challenging.
Didik Aryanto
Zulkafli Othaman
Abd. Khamim Ismail
2014-08-20T08:15:08Z
2017-08-20T00:33:47Z
http://eprints.utm.my/id/eprint/id/eprint/40896
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40896
2014-08-20T08:15:08Z
Survival data analysis using additive and multiplicative gamma polygonal hazards function
Proportional hazards model (PHM) is commonly used in survival analysis for estimating the effects of different covariates influencing the survival data. The hazard function in proportional hazards model (PHM) is commonly defined as a product of the baseline hazard function and a non-negative function of covariates. However, the hazard function may also be presented as the sum of the baseline hazard function and a nonnegative function of covariates. We propose the new additive and multiplicative Gamma Polygonal in the hazards function using OpenBugs Statistical Packages. Both models are an alternative to the existing additive and multiplicative models but the new additive Gamma polygonal intensity model is quite complex compared to the new multiplicative Gamma polygonal intensity model. The application for right-censored data from Bayesian perspective will be discussed and the Markov Chain Monte Carlo (MCMC) method will be used to compute the Bayesian estimator using Leukemia data and DSR data. The results obtained show that the propose model is as good as the existing models in analyzing paired survival data.
Noraslinda Mohamed Ismail
Zarina Mohd. Khalid
Norhaiza Ahmad
2014-08-20T08:15:07Z
2017-08-16T08:23:43Z
http://eprints.utm.my/id/eprint/id/eprint/40888
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40888
2014-08-20T08:15:07Z
The effectiveness of MEWMA control chart with mild correlation
Since it is undeniable that whenever conventional control charts are used there is the implied presumption that this observations tend to be independently as well as identically distributed with time. However, in reality, this kind of observations generated through continuous as well as discrete production procedures tend to be serially correlated, which violates the independence assumption of conventional control charts in addition to affect the performance of control charts negatively. In this paper, we investigate the performance of MEWMA control chart with autocorrelated data with mild correlation being controlled. The generated data were applied to MEWMA control chart procedure and showed an in-control state, while the generated observations were subjected to normality tests from the assumptions and sensitivities for departure to normality, and turned out to be normal by all standard. Hence, this gives an alternative for the quality practitioners to adopt for the continuous and discrete production processes also the autocorrelation has no effect on the performance of MEWMA control limits when the mild correlation has been controlled.
Abbas Umar Farouk
Ismail Mohamad
Gazali Abdulhameed M.
2014-08-20T08:15:04Z
2017-11-01T04:17:11Z
http://eprints.utm.my/id/eprint/id/eprint/40884
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40884
2014-08-20T08:15:04Z
Thermoluminescence performance of carbon-doped aluminium oxide for dose measurement by various preparation methods
Thermoluminescent dosimeter (TLD) of carbon–doped aluminium oxide (a–Al2O3:C) produced in the form of single crystals show high sensitivity to ionizing radiation (about 40–60 times higher than TLD–100 (LiF:Mg,Ti)). The present article offers a review of the materials preparation and corresponding thermoluminescence (TL) properties of a–Al2O3:C subjected to various types of ionizing radiations. Different methods of a–Al2O3:C preparation in form of single crystal and thin films are reviewed. The development of methods of preparation is based on the approaches that involve the evaluation of the luminescence light yield in TL process. Most of the methods used were suitable, but each of these methods has their advantages and disadvantages depending on the required form of materials. Considering the results presented by various authors, possible better method of material preparation is proposed. The potential alternative fabrication technique of a–Al2O3:C thin film by using radio–frequency magnetron sputtering is briefly discussed.
Chuey Yong Leong
Husin Wagiran
Abd. Khamim Ismail
2014-08-20T08:15:03Z
2017-10-08T08:25:01Z
http://eprints.utm.my/id/eprint/id/eprint/40894
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40894
2014-08-20T08:15:03Z
Thermoluminescence properties of doped silica glass for applications in radiation therapy dosimetry system
Ahmad Lutfi Yusoff
Hafiz Zin
Ahmad Lutfi Abdul Rahman
Mohd. Iqbal Saripan
Ahmad Taufek Abdul Rahman
Nurul Arina Zahaimi
David Andrew Bradley
Mohd. Haris Ridzuan Ooi Abdullah
Suhairul Hashim
2014-08-20T08:15:01Z
2017-08-16T08:54:20Z
http://eprints.utm.my/id/eprint/id/eprint/40889
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40889
2014-08-20T08:15:01Z
The evolution of foreign exchange market based on european sovereign debt crisis
This study examined the network topology of international foreign exchange markets from 2009 to 2012 in terms of European sovereign debt crisis by using the minimum spanning tree (MST) approach. In the process, the time series evolution is analyzed in relation to the structure changes of MSTs during the crisis period. By deriving some notable changes in network feature, we compare their properties for two subdivided period of currency crisis.
Mansooreh Kazemi Lari
Maman Abdurachman Djauhari
2014-08-20T08:15:00Z
2017-08-17T06:18:29Z
http://eprints.utm.my/id/eprint/id/eprint/40891
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40891
2014-08-20T08:15:00Z
Temperature-controlled selectivity in oxidation of 1-octene by using aqueous hydrogen peroxide in phase-boundary catalytic system
Temperature-controlled selectivity in oxidation of 1-octene by using aqueous hydrogen peroxide in phase-boundary catalytic system was demonstrated by using alkylsilylated-Ti(IV) salicylaldimine complex at a series of temperature (25–90 °C). The catalyst was synthesized by titanium(IV) sulfate solution, salicylaldehyde, and 3-aminopropyltrimethoxysilane as the precursors and followed by the attachment of octadecyltrimethoxysilane. It was found that the reaction system resulted in high selectivity at low temperature. One suggests that the high selectivity in the oxidation of 1-octene by aqueous hydrogen peroxide was related to partitioning of alkylsilylated-titanium(IV) salicylaldimine complex in immiscible liquid–liquid phase boundary which is temperature dependent.
Sin Yuan Lai
Rasidah Razali
Jon Efendi
Nor Aziah Buang
Hadi Nur
2014-08-20T08:14:59Z
2017-08-17T06:31:51Z
http://eprints.utm.my/id/eprint/id/eprint/40892
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40892
2014-08-20T08:14:59Z
The comparison of T-Mode and Pearson Correlation matrices in classfication of daily rainfall patterns in Peninsular Malaysia
The aim of this study is to identify daily rainfall patterns of wet days linked to the topography of Peninsular Malaysia using two different configurations of points in the data. The data used in this study were obtained from 75 rain gauge stations in Peninsular Malaysia from the year 1975-2007. We only consider data for the period in which southwest monsoon occur from June until September yielding a total of 153 days.A typical classification approach in identifying daily rainfall patterns requires the use of configuration points of entities between the rows and column of the data based on correlation matrices. In this study, we compare effect on the cluster of daily rainfall patterns on two types of correlation matrices: T-mode correlation matrix and Pearson correlation matrix. These matrices are then used as inputs for Principal Component Analysis (PCA) to reduce the dimension of the dataset before clustering the rainfall patterns of wet days. We have found that although Tmode correlation matrix is popularly used in subtropical climate studies, it is unable to show clear classification in defining daily rainfall patterns in tropical climate data. Using Calinski and Harabasz Index, only two-rainfall pattern cluster can be identified on T-mode correlation matrix. On the other hand, Pearson correlation matrix showed three different rainfall patterns and each cluster are identified to be linked to certain topographic characteristics. These three clusters indicate that the rainfall pattern during the southwest monsoon experiencing the most heavy rain in the western part of the Peninsula, particularly in characterizing the rainfall pattern of the northwestern and western region of Peninsular Malaysia. These clusters are mapped out using ARCGIS software.
Shazlyn Milleana Shaharudin
Norhaiza Ahmad
Fadhilah Yusof
Yap Xen Quan
2014-08-20T08:14:59Z
2017-08-20T00:31:47Z
http://eprints.utm.my/id/eprint/id/eprint/40895
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40895
2014-08-20T08:14:59Z
Spatial interaction of electroencephalography signal during epileptic seizure on flat electroencephalography
Electroencephalography (EEG) is one of the fields in clinical neurophysiology, which is a recording of the electrical activity of the brain from the scalp. One of the major roles of EEG is as an aid to diagnose epilepsy. Abnormal patterns such as spikes, sharp waves and, spikes and wave complexes can be seen. It is important to extract spatial information about the dynamics from a few observations of this recorded signal regardless where EEG sensors are located. A developed method by Theoretical & Computational Modelling for Complex System (TCM), UTM, namely Flat EEG for mapping high dimensional signal into a low dimensional space will be used as platforms to analyse EEG signal spatially during epileptic seizure. The spatial interactions among clusters are identified through spatial interaction model, namely gravity model. This paper also reveals that gravity model used is a measure.
Chien Yong Goh
Tahir Ahmad
Normah Maan
2014-08-19T03:38:52Z
2019-03-05T02:54:26Z
http://eprints.utm.my/id/eprint/id/eprint/40249
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40249
2014-08-19T03:38:52Z
Comparison of activity concentration of 238U, 232Th and 40K in different layers of subsurface structures in DeiDei and Kubwa, Abuja, North Central Nigeria
The study of activity concentration of 232Th, 238U and 40K of rock samples from site one (S1L1–S1L11, 70 m) and site two (S2L1–S2L9, 60 m) boreholes in Dei-Dei and Kubwa was presented and the first time in the region to be compared. Activity concentrations were analysed using a high resolution co-axial HPGe gamma ray spectrometer system. The activity concentration ranges in site one borehole were from 45±1 to 98±6 Bq kg−1 for 232Th, from 18±2 to 37±4 Bq kg−1 for 238U and from 254 ±32 Bq kg−1 to 1195 ±151 Bq kg−1 for 40K. The activity concentration ranges in site two borehole were from 32±3 to 84±7 Bq kg−1 for 232Th, from 15±2 to 52±5 Bq kg−1 for 238U and from 119±15 to 705±94 for 40K Bq kg−1. Significantly higher concentration of 232Th and 238U occurs in samples collected from S1L7, S1L11 and S2L1 layers. These zones experienced granitic intrusions produced by denudation and tectonism. 40K in rock samples of S1L4 and S2L4 activity concentrations is close; it could be that biotite granitic intrusion that is inferred as the formation in that layer reflects the same activity of potassium in rock's radioactivity measurement. The area requires further investigation of soil geochemistry and activity concentration of radionuclides in groundwater.
Omeje Maxwell
Husin Wagiran
Noorddin Ibrahim
Siak Kuan Lee
Soheil Sabri
2014-08-19T03:38:52Z
2019-03-05T01:34:20Z
http://eprints.utm.my/id/eprint/id/eprint/40252
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40252
2014-08-19T03:38:52Z
Determination of bestfit distribution and rainfall events in Damansara and Kelantan, Malaysia
This paper presents a study to determine the best-fit distribution to represent the rainfall process in Damansara and Kelantan, Malaysia. Three probability density functions, namely Wakeby distribution, Generalized Extreme Value function (GEV) and two-parameter Weibull distributions are selected and compared. The parameters of the distributions are estimated using L-moments method while the best-fit distribution is determined by using Kolmogorov-Smirnov goodness-of-fit test. In addition, weighted-average algorithm which is based on the probability values from the stations in Damansara and Kelantan is used to identify the occurrence of wet and dry events in the rainfall data. The impact of different distributions used in the determination of rainfall events is evaluated by making comparison between the actual and the reconstructed rainfall data. The results indicate that the Wakeby distribution is the best-fit distribution to explain the rainfall patterns in Damansara and Kelantan. However, Wakeby, GEV and Weibull distributions perform equally well in the estimation of wet and dry events in Damansara and Kelantan.
Fadhilah Yusof
Kang Ho Ming
2014-08-19T03:38:52Z
2019-03-05T02:54:25Z
http://eprints.utm.my/id/eprint/id/eprint/40253
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40253
2014-08-19T03:38:52Z
Elucidation of active species over Ru/Mn/Al2O3 catalyst on CO2/H2 methanation reaction
The information regarding phase changes and structure transformation, particle sizes as well as active species of the catalyst are briefly discussed towards alumina supported Ru/MnO catalysts according to their various parameters of calcination temperatures and Mn loading. The Ru/Mn-75/Al2O3 catalysts calcined at 400˚C, 700˚C, 900˚C, 1000˚C and 1100˚C, Ru/Mn-65/Al2O3 and Ru/Mn-85/Al2O3 catalyst calcined at 1000˚C were synthesized by the wetness impregnation method. All the prepared catalysts exhibited crystallite size in the range of 95 nm to 114 nm. It was found that the catalyst with Ru/Mn-75/Al2O3 calcined at 1000˚C showed the highest 60.21% CO2 conversion with 57.84% formation of CH4 at the reaction temperature 200˚C. The expected active species that assist the CO2 methanation activity over this catalyst was Mn3O4.
Wan Azelee Wan Abu Bakar
Rusmidah Ali
Susilawati Toemen
Hazwan Faiz Abd. Rahim
2014-08-19T03:38:52Z
2019-03-05T01:34:18Z
http://eprints.utm.my/id/eprint/id/eprint/40256
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40256
2014-08-19T03:38:52Z
First nuclear power in Nigeria: an attempt to address the energy crisis?
This paper attempts to explore to what extent a first Nuclear Power Plant (NPP) will improve the energy situation in Nigeria and investigates the socio-economic impacts of the NPP on the communities where the facilities are to be sited. Other issues that are addressed in this paper include the policy issues, lack of investments in power infrastructure and the security threat owing to incessant domestic militancy or terrorism. The paper then outlines the ways to tackle these problems and concludes that despite the facts that the addition of nuclear power into Nigeria's energy mix will help in curtailing the country's energy crisis, it also poses some challenges to the country that the policy and decision-makers must take into consideration right from the preliminary stages of the programme.
Ahmad Termizi Ramli
Abubakar Sadiq Aliyu
Muneer Aziz Saleh
2014-08-19T03:38:52Z
2019-03-17T04:21:47Z
http://eprints.utm.my/id/eprint/id/eprint/40264
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40264
2014-08-19T03:38:52Z
Kinematic motion of positive carbon ion species : a proposal method
The ion carbon species are massively produced througharc plasma for synthesizing carbon nanotube. Positive ions would have tendencies to move towards the negative charged cathode. The moving of the massive ions generated electric field in direction parallel with the ion movement. In this paper, we discuss the particle collisions subsequently resulting a new carbon species namely carbon nanotube (CNT) composed from single/many graphene layer rolled up alike nanostraw structure.Keyword:.
M. Saktioto Roslana
Jalil Ali
2014-08-19T03:38:51Z
2019-03-05T01:34:17Z
http://eprints.utm.my/id/eprint/id/eprint/40257
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40257
2014-08-19T03:38:51Z
Forensic entomology in Malaysia: a review
Forensic entomology has been regarded as one of the most useful fields in forensic sciences especially in estimating postmortem interval. Since the last 30 years, researches in this field have evolved tremendously throughout the world, which ranged from factors influencing the development of necrophagous insects, the use of molecular-based techniques in assisting taxonomic identification of species, to the use of necrophagous insects in drawing toxicological inferences. In Malaysia, researches on species compositions and development of necrophagous insects recovered from dead bodies as well as infesting animal models decomposing in various conditions have been conducted in several states viz. Selangor, Kuala Lumpur, Penang, Kedah and Kelantan. However, such data from the other states within Peninsular Malaysia as well as from the East Malaysia i.e. Sarawak and Sabah are currently lacking. Although data on the influence of malathion and gasoline on species composition and development of necrophagous insects are available, similar studies focusing on other poisons that are used for committing suicides such as paraquat and other pesticides as well as rodenticides have not been reported, so far. In the context of taxonomic identification of species using molecular-based techniques, the use of cytochrome oxidase genes has been attempted. In addition, quantitative and qualitative determinations of poisons in necrophagous maggots for suggesting the cause of death have been reported. This paper reviews all pertinent studies conducted in the field of forensic entomology in Malaysia.
Naji Arafat Mahat
Pt. Jayaprakash
2014-08-19T03:38:51Z
2019-03-17T04:21:43Z
http://eprints.utm.my/id/eprint/id/eprint/40260
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40260
2014-08-19T03:38:51Z
Germanium nanoislands grown by radio frequency magnetron sputtering grown germanium nanoislands: annealing time dependent surface morphology and photoluminescence
Structural and optical properties of ~ 20 nm Ge nanoislands grown on Si(100) by radio frequency (rf) magnetron sputtering under varying annealing conditions are reported. Rapid thermal annealing at a temperature of 600°C for 30 s, 90 s, and 120 s are performed to examine the influence of annealing time on the surface morphology and photoluminescence properties. X-ray diffraction spectra reveal prominent Ge and GeO2 peaks highly sensitive to the annealing time. Atomic force microscope micrographs of the as-grown sample show pyramidal nanoislands with relatively high-density 1011 cm-2)). The nanoislands become dome-shaped upon annealing through a coarsening process mediated by Oswald ripening. The room temperature photoluminescence peaks for both as-grown 3.29 eV) and annealed 3.19 eV) samples consist of high intensity and broad emission, attributed to the effect of quantum confinement. The red shift (~0.10 eV) of the emission peak is attributed to the change in the size of the Ge nanoislands caused by annealing. Our easy fabrication method may contribute to the development of Ge nanostructure-based optoelectronics.
Zulkafli Othaman
Alireza Samavati
S. K. Ghoshal
R. J. Amjad
2014-08-19T03:38:51Z
2019-01-28T03:54:14Z
http://eprints.utm.my/id/eprint/id/eprint/40265
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40265
2014-08-19T03:38:51Z
Characterization of hydrated lime-stabilized brown kaolin clay
The effect of the calcium-based stabilizers like lime on the clay soil characterizations has been studied in this research. This study was carried out in an attempt to identify the time-dependent soil chemical reactions for lime chemically stabilized Brown Kaolin clay samples. The data for the study of characteristics of treated samples were obtained from X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR). Furthermore, to illustrate the effect of lime on the strength, a series of laboratory tests were carried out by unconfined compressive strength. Based on the micro-structural analyses, it was observed that kaolinite is rapidly exhausted by pozzolanic reactions to produce the Gismondine (CASH), which is responsible on gain the strength for the lime treated samples with progressing time. On the other hand, it was noticed Illite mineral did not show any reacted with advancing time. In addition, based on the morphology of the treated samples, the presence of the cementious products were observed. These outcomes proved the effectiveness of lime to stabilize kaolin clay.
Khitam Abdul Hussein Saeed
Khairul A. Kassim
Hadi Nur
Nor Zurairahetty Mohd. Yunus
2014-08-19T03:38:50Z
2019-03-05T01:34:19Z
http://eprints.utm.my/id/eprint/id/eprint/40255
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40255
2014-08-19T03:38:50Z
Fast, slow, stopping and storing light simultaneously using a PANDA ring on chip
Past and slow light behaviors are the interesting aspects of light which can be useful for many fundamental and applied researches. Pornsuwancharoen and Yupapin et al. [1] have proposed the use of a simple device called “microring resonator” to perform such behaviors. In this research work, the four different behaviors of light i.e., fast, slow, stopping and storing of light where investigated using a ring resonator. Nowadays, stopping or cooling light beam has become the promising technique for atom/molecule trapping investigations (using static or dynamic tweezers), especially, after the announcement of Nobel Prize 2012 in Physics on the whispering gallery modes [2, 3]. There are two more kinds of devices that can be used to trap light beams, the use of microcavity arrays performed by Yanik and Fan [4], and nonlinear microring resonator by Yupapin and Pornsuwancharoen [5] for stopping light (laser beam). Nanyang Technological University scientists have also done experiment to slowing the light in microresonators using a microring system recently [6]. This concept is a concrete backbone for many applications.
Muhammad Arif Jalil
Jalil Ali
N. Sarapat
W. Khunnam
S. Chiangga
N. Thammawongsa
P. P. Yupapin
2014-08-19T03:38:50Z
2019-03-05T01:34:17Z
http://eprints.utm.my/id/eprint/id/eprint/40258
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40258
2014-08-19T03:38:50Z
Functional data analysis technique on daily rainfall data: a case study at North Region of Peninsular Malaysia
The study of rainfall features and patterns are very useful for water management systems, water resources engineering and also in agricultural planning. It can be beneficial in order to reduce the risks and losses. Functional data analysis technique is one of the method can be used to explore and display the pattern and variation of the rainfall data. This technique displays the pattern in the form of curves. The first and second derivatives of the curves represent the rate of change and the acceleration of the curves. The objective of the study is to model two rainfall features; rainfall amount and rainfall occurrence by using functional data analysis technique at eight rainfall stations from the north part of Peninsular Malaysia. Markov chain model has been used to model the rainfall occurrence and Fourier basis to smoothing the data. The results show that both of the rainfall features have similar bimodal pattern. Although the mean curves are slightly similar, the first peak of variance curve for rainfall occurrence is higher than the second peak which is difference with variance curve for rainfall amount. The relationship between rainfall amount and rainfall occurrence for both observed and estimated curve is also discussed
Muhammad Fauzee Hamdan
Shariffah Suhaila Syed Jamaludin
2014-08-19T03:38:50Z
2019-03-17T04:21:46Z
http://eprints.utm.my/id/eprint/id/eprint/40262
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40262
2014-08-19T03:38:50Z
Indo and Indon : an epistemological perspective
Many Indonesians that I met, from laymen to highly educated people, have a hard feeling when they hear the word “Indon”. It is not so when they are called “Indo”. Some believe that the former is not appropriate to use as an expression in communication. Is that belief true? Is the true belief justified? Or is it an opinion? Truth, belief, and justification are the tripartite that construct knowledge. This construct brings us to analyze the two words from epistemological perspective before we go into an etymological study.
Maman Abdurachman Djauhari
2014-08-19T03:38:49Z
2019-03-05T01:34:21Z
http://eprints.utm.my/id/eprint/id/eprint/40251
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40251
2014-08-19T03:38:49Z
Continua and separation of the components of fuzzy topographic topological mapping
The mathematical model Fuzzy Topographic Topological Mapping (FTTM) is used to solve
neuromagnetic inverse problem during a seizure in order to determine the location of epileptic foci.
Continuum and separation axioms are topological properties. In this paper, the properties of
connectedness, compactness, and separations for the components of FTTM are presented.
Tahir Ahmad
Hiyam Hassan Kadhem
2014-08-19T03:38:49Z
2019-03-05T01:34:16Z
http://eprints.utm.my/id/eprint/id/eprint/40259
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40259
2014-08-19T03:38:49Z
Fuzzy topological digital space of flat electroencephalography during epileptic seizures
Epileptic seizures are manifestations of epilepsy caused a temporary electrical disturbance in a group of brain cells. Electroencephalography (EEG) is a recording of electrical activity of the brain and it contains valuable information related to the different physiological states of the brain. Flat EEG (fEEG) was developed to compress and analyze information in the brain during epileptic seizures obtained from EEG signal. In this study, the fEEG is made in digital form by using Voronoi digitization. Khalimsky fuzzy topology and fuzzy topological digital space is constructed to be used in studying properties fuzzy topology of fEEG. It is obtained that fEEG is a fuzzy topological digital space and t-connected.
Tahir Ahmad
Muhammad Abdy
2014-08-19T03:38:49Z
2019-03-17T04:21:45Z
http://eprints.utm.my/id/eprint/id/eprint/40261
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40261
2014-08-19T03:38:49Z
Improved cluster partition in principal component analysis guided clustering
Principal component analysis (PCA) guided clustering approach is widely used in high dimensional data to improve the efficiency of K- means cluster solutions. Typically, Pearson correlation is used in PCA to provide an eigen-analysis to obtain the associated components that account for most of the variations in the data. However, PCA based Pearson correlation can be sensitive on non-Gaussian distributed data, which involve skewed observations such as outlying values. Thus, applying PCA based Pearson correlation on such data could affect cluster partitions and generate extremely imbalanced clusters in a high dimensional space. In this study, Tukey's biweight correlation based on M-estimate approach in PCA is used as an alternative to Pearson correlation. This approach is more resistant to outlying values as it examines each observation and down weight those that lie far from the center of the data. In particular two major features are highlighted: (1) fewer components are retained and imbalanced clusters at the recommended cumulative percentage of variation threshold is avoided; (2) the cluster quality with respect to external, internal and relative criteria as shown in Rand, Silhouette and Davies-Bouldin indices, outperform that of the clusters from PCA based Pearson correlation.
S. M. Shaharudin
Norhaiza Ahmad
Fadhilah Yusof
2014-08-19T03:38:49Z
2019-01-28T03:54:14Z
http://eprints.utm.my/id/eprint/id/eprint/40254
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40254
2014-08-19T03:38:49Z
Equilibrium and kinetic studies of acid dye adsorption on palm oil empty fruit bunch
Palm oil empty fruit bunch (POEFB), an agricultural waste, used as low-cost adsorbent for removal Acid Orange 51 (AO51) dye from aqueous solutions was studied. Batch mode experiments were carried out at room temperature (28 ± 2) °C to study the effects of contact time and initial dye concentrations (10-200 mg/L). The equilibrium adsorption data of AO51 dye on empty fruit bunch were analyzed by three isotherms, namely the Langmuir isotherm, Freundlich isotherm and Temkin isotherm model. The result indicated that the equilibrium sorption fitted well with the Freundlich isotherm, displaying higher regression coefficient, R2value. The monolayer adsorption capacity of POEFB was found to be 166.67 mg/g. The kinetic data obtained at different concentrations have been analyzed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models. It was shown that pseudo-second-order kinetic model could best describe the adsorption kinetics.
Norini Tahir
Zaiton Abdul Majid
2014-08-19T03:38:48Z
2019-03-17T04:21:47Z
http://eprints.utm.my/id/eprint/id/eprint/40263
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40263
2014-08-19T03:38:48Z
InVitro characterization of antibacterial bioactive glass containing ceria
Several compositions of bioactive glass (BG) containing ceria were synthesized from chloride precursor using quick alkali sol–gel method. XRD data revealed the presence of ceria in 5 and 10 mol% Ce samples. SEM and EDX characterization confirmed the nano-size and elemental composition of all samples, while FTIR data indicated that high Ce content has disrupted the silicate network of BG. UV absorption spectrum showed that ceria in BG samples is present in +3 and +4 oxidation states, depending on the initial cerium content. Nitrogen adsorption–desorption isotherm confirmed the mesoporosity of the samples. 5 and 10 mol% Ce samples exhibited significant antibacterial properties compared to 1Ce and 50Si samples. All samples induced the formation of apatite particles with Ca/P ratio close to 1.67 upon immersion in simulated body fluid (SBF), confirming their good bioactivity. For the first time, this study has demonstrated that cerium is a promising candidate to impart BG with excellent antibacterial properties without compromising its bioactivity.
Mohammed Rafiq Abdul Kadir
Rafaqat Hussain
Yi Fan Goh
Ammar Z. Alshemarya
Muhammad Akram Muhammad Akram
2014-08-19T00:41:35Z
2019-03-26T08:07:59Z
http://eprints.utm.my/id/eprint/id/eprint/40407
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40407
2014-08-19T00:41:35Z
Effect of iridium loading on the formation of protonic acid sites over Ir/PtHZSM5
The Ir/Pt-HZSM5 with different iridium loading (0.3-1.0 wt%) was prepared by impregnation of iridium on Pt-HZSM5. The acidic properties of Ir/Pt- HZSM5 were studied by FTIR spectroscopy, while the activity of the catalysts was tested for n-pentane isomerization in a microcatalytic pulse reactor. The IR results of adsorbed 2,6-lutidine showed that all catalysts possessed strong Brönsted and Lewis acid sites in the outgassing at 473 K and below. When Ir/Pt-HZSM5 was heated in hydrogen, protonic acid sites were formed with concomitant decrease of Lewis acid sites. An increase in iridium loading continuously decreased the Lewis and Brönsted acid sites and inhibited the formation of protonic acid sites induced by hydrogen. The formation of protonic acid sites induced by hydrogen was also confirmed by the formation of electron detected by ESR spectroscopy. Additionally for n-pentane isomerization, an increase in iridium loading decreased the yield of isopentane due to the inhibition in the formation of protonic acid sites via hydrogen spillover phenomenon.
H. D. Setiabudi
Aishah Abd. Jalil
Sugeng Triwahyono
S. N. Timmiati
N. H. R. Annuar
N. A. A. Fatah
M. R. Sazegar
L. P. Teh
2014-08-19T00:41:35Z
2019-03-26T08:08:02Z
http://eprints.utm.my/id/eprint/id/eprint/40410
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/40410
2014-08-19T00:41:35Z
Biogas production through co-digestion of palm oil mill effluent with cow manure
Palm oil mill effluent (POME) and cow manure (CM) are excellent substrates for biogas production. Biogas production potentials from POME and CM as a single substrate were extensively researched by many researchers. In this work, the biogas potentials from POME and CM as a single substrate as well as co-substrates were investigated. In addition, the effect of removal efficiencies of chemical oxygen demand (COD) and volatile solids (VS) towards biogas production and its methane content were also investigated. Batch anaerobic digesters used for the digestion were operated at ambient temperature (28oC to 34°C) for 21 days. The digesters were operated at different mixing ratios. Maximum cumulative biogas yield and its methane content were obtained as 1875ml and 61.13%, respectively in the mixture containing 70: 30 (POME: CM). Co-digestion of 70% POME + 30% CM improved the removal efficiency up to 75% (COD) and 68% (VS). Biogas yield from digesters D3, D4 and D5 were improved by 21%, 162% and 110% v/v using the codigestion as compared to the digestion of POME alone and 95%, 323% and 240% v/v as compared to the digestion of CM alone respectively. These results show that biogas and its methane content production can be enhanced efficiently through co-digestion process.
Umar Hayatu Sidik
Firdausi Razali
Sharifah Rafidah Wan Alwi
Fadimtu Maigari
2014-07-03T05:13:35Z
2017-07-17T07:50:05Z
http://eprints.utm.my/id/eprint/id/eprint/39742
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39742
2014-07-03T05:13:35Z
Properties of 4-fluorobenzoic acid modified zinc oxide nanoparticles by sol-gel method
Metal oxide semiconductor has been widely studied due to it varied properties and application. Among metal oxide, ZnO semiconductor is of great interest due to the wide bandgap (3.2-3.4 eV) with hexagonal wurtzite structure. This study involves preparing ZnO by sol-gel method and the comparison of optical properties of ZnO nanoparticle at (350 and 450ºC) before and after modifying with 4-fluorobenzoic acid (4-FBA). The optical properties were studied using UV-Vis-NIR scanning spectrophotometer. FESEM image shows that the irregular spherical shape and there is variation in the surface morphology of modified and unmodified ZnO nanoparticle. The grain size increased with increasing temperature, but with addition of modifier the particle size didn’t change. The bandgap decrease with increasing temperature but recorded no changes after applying modifier. The XRD patterns of these samples are in close agreement with the JCPDS standard (No. 36-1451). It was observed that all samples were polycrystalline with hexagonal wurtzite structure with diffraction peaks oriented along the (100), (002), (101), (102), (110) and (103) planes. Fourier transforms infrared spectroscopy (FTIR) showed a band of 400-600 cm-1 corresponding to the Zn-O vibration mode.
Hozan Salahuddin Ahmed
2014-07-03T05:09:22Z
2017-06-21T04:58:14Z
http://eprints.utm.my/id/eprint/id/eprint/39747
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39747
2014-07-03T05:09:22Z
Optical and physical properties of europium doped lithium potassium borate glass
Borate glass is widely used in many scientific studies. By using melt-quenching technique five samples of lithium potassium borate (LKB) doped with different concentration of europium oxide (Eu2O3) were prepared. To investigate the influence of dopant on the optical and physical characteristics of the glass, X-ray Diffraction and photoluminescence analyses were performed. The amorphous nature was confirmed by X-ray diffraction. The physical parameters of the glass which was doped by different oxidation state have been analyzed. These parameters involved are density, molar volume, ion concentration, inter-nuclear distance and Polaron radius. The exchange in the concentration of Eu+3 indicated the influence of Eu as a dopant on the photoluminescence emission of LKB glasses. The photoluminescence emission spectrum of LKB:Eu+3were due to the transition of Eu3+ from5D0-7Fr (r =1, 2, 3 and 4). The luminescence studies showed four peaks (590 nm, 613 nm, 650 nm, and 698 nm) for all samples excluding the pure sample. The glow curve exhibits single peak at 164 ºC. We establish that the proposed TL dosimeter at 0.5 mol% of Eu3+ has been observed to be 20 times less sensitive than TLD-100.
Majdi Mohammad Alayan Maqableh
2014-07-03T01:02:37Z
2017-07-13T06:48:04Z
http://eprints.utm.my/id/eprint/id/eprint/39737
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39737
2014-07-03T01:02:37Z
Synthesis of hydroxylated and prenylated chalcones
Prenylated chalcones are among the compounds found in local Artocarpus species which reported to have interesting biological activities. Moreover, prenylated chalcones are used as traditional folk medicine for the treatment of inflammation, malarial fever and to treat the ulcers and diarrhea. In this study, 2,4-dihydroxy-3-C-prenylacetophenone and 2,4-dihydroxy-5-C-prenylacetophenone were successfully synthesized by treating resacetophenone with 2-methylbut-3-en-2-ol in the presence of BF3.Et2O as the catalyst. Meanwhile 2,4,6-trihydroxy-3-C-prenylacetophenone was synthesized using K2CO3 as the catalyst in dry acetone in the reaction of prenyl bromide with 2,4,6-trihydroxyacetophenone . In addition, two hydroxylated chalcone namely 2',4',4-trihydroxychalcone , 4',4-dihydroxychalcone) together with 2',4',4,6'-tetrahydroxy-3'-prenylchalcone were synthesized by Claisen-Schmidt condensation of various hydroxyacetophenone and 2,4,6-trihydroxy-3-C-prenylacetophenone for prenylated chalcone with 4-hydroxybenzaldyhe using BF3.Et2O. The structures of all compounds were characterized using spectroscopic methods (NMR and IR).
Aso Hameed Hasan
2014-06-30T08:14:37Z
2017-09-26T03:52:21Z
http://eprints.utm.my/id/eprint/id/eprint/39303
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39303
2014-06-30T08:14:37Z
Integral representations of metacyclic groups over a local field
Let G be a group generated by two elements α and β such that αt = 1. Then the commutator of G, δ=αβα- 1β-1 commutes with α and β where δt = 1 and t = pm Furthermore, G is known as an integral representation over a local field. In this paper, the integral representations of metacyclic groups over a local field are determined.
Noor Asma Adny Mohd. Adnan
Nor Haniza Sarmin
Nor Muhainiah Mohd. Ali
Zainab Yahya
Hamisan Rahmat
2014-06-30T08:14:25Z
2017-09-12T08:13:15Z
http://eprints.utm.my/id/eprint/id/eprint/39169
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39169
2014-06-30T08:14:25Z
Identification of rainfall patterns in Johor
Temporal pattern for rainfall events is required in the design and evaluation of hydrologic safety for hydraulic structures. In this paper, a method of statistical cluster analysis is applied to identify event-based representative temporal rainfall pattern in fourteen stations in Johor. The 8 hour separation time of no rain is used to divide the 5 years rainfall data into individual rainfall event according to the monsoons. The analysis is implemented from the dimensionless mass curve ordinates as the attributes in statistical cluster analysis of the cumulative storm depth over the non-dimensionalized time. As a result, three representative rainstorm patterns are identified and classified under the two basic types of advanced-type (A) and central-peak type (C) for northeast and southwest monsoon. Meanwhile, only one basic type is identified to represent rainstorm pattern during the inter-monsoon that is advanced type (A). In addition, the rainfall pattern is found to be dependent on rainfall depth and duration, season and geographical location by using the contingency table test. Therefore, the identification of only one rainfall pattern as currently used in Malaysia is not sufficient. The identification of three representative rainfall temporal patterns according to the monsoon seasons in Johor can be used as a basis to stochastically generate the plausible rainfall hyetographs of the specified pattern in Johor.
Nur Syereena Nojumuddin
Fadhilah Yusof
Zulkifli Yusop
2014-06-30T08:00:53Z
2017-09-26T07:46:03Z
http://eprints.utm.my/id/eprint/id/eprint/39591
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39591
2014-06-30T08:00:53Z
History tracting ability of second and fourth orders runge-kutta in solving delay differential equations
Sih Lim Rui
Rohanin Ahmad
Su Hoe Yeak
2014-06-30T08:00:51Z
2014-06-30T08:00:51Z
http://eprints.utm.my/id/eprint/id/eprint/39554
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39554
2014-06-30T08:00:51Z
Developing multiple linear regression model fordioxin furan emission in the incineration process
Normah Maan
2014-06-30T07:55:07Z
2017-09-27T04:02:20Z
http://eprints.utm.my/id/eprint/id/eprint/39614
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39614
2014-06-30T07:55:07Z
Efficient Oxidative Desulfurization (ODS) of commercial diesel with TBHP under mild conditions catalyzed by polymolybdates supported on Al2O3
Due to the low specifications for sulfur content in diesel, a lot of research work are been conducted to develop alternative method for desulfurization. Catalytic oxidative desulfurization (Cat-ODS) has been found to be an alternative method to replace a conventional method which is hydrodesulfurization.New catalyst formulation using tert-butyl hydroperoxide polymolybdate based catalyst system was investigated in this research utilizing tert-butyl hydroperoxide (TBHP) as oxidant and dimethylformamide (DMF) as solvent for extraction. A series of polymolybdate supported alumina catalysts were prepared using wet impregnation method, ageing at ambient room temperature for 24 hours and followed by calcination process. A commercial diesel with 440 ppmw of total sulfur was employed to evaluate the elimination of sulfur compounds. Besides, the percentage of sulfur removal was measured by gas chromatography-flame photometric detector (GC-FPD). The sulfur content in commercial diesel was successfully reduced from 440 ppmw to 35 ppmw under mild condition followed by solvent extraction. From catalytic testing, Mo-Al2O3 calcined at 500°C was revealed as the most potential catalyst which gave 92% of sulfur removal.
Rusmidah Ali
Wan Nazwanie Wan Abdullah
Wan Azelee Wan Abu Bakar
2014-06-30T07:55:07Z
2017-09-27T04:04:17Z
http://eprints.utm.my/id/eprint/id/eprint/39615
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39615
2014-06-30T07:55:07Z
Green technology purification of natural gas via Co2/H2 methanation by using trimetallic Ru/Mn/Fe-Al2O3 oxide catalyst
The presence high content of carbon dioxide (CO2) and hydrogen sulphide (H2S) in crude natural gas which can block cryogenic equipments and favours steel-pipes corrosion thus will decrease the quality of the natural gas. Therefore, there is need to treat sour to sweet natural gas by using green technology via catalytic methanation reaction by converting CO2 to methane gas. Using waste to wealth concept, production of methane would increase as well as creating environmental friendly approach for purification of natural gas. In this work, the investigations of new trimetallic Ru/Mn/Fe-Al2O3 oxide catalysts were conducted and the catalysts were prepared by wet impregnation method. The catalysts were activated at different temperatures (100-1100°C) for 5 hours and at different ratios of metal. The additions of Ru into catalysts had improved the CO2 conversion and CH4 formation compared with the undoped. Ru/Mn/Fe (5:35:60)/Al2O3 catalyst calcined at 1000°C was assigned as the most potential catalyst, which gave 96.1% CO2 conversion at reaction temperature of 270°C. Moreover, the XRD diffractograms showed that the catalyst calcined at high temperature were highly crystalline phase while, catalysts calcined at low temperature showed highly amorphous in structure which was dominated by Al2O3 support material. The FESEM analysis revealed that fresh and used catalyst were covered with homogeneously dispersed and small size surface particles in the range of 0.2-0.4 μm. Nitrogen adsorption analysis showed, the surface area increased from single to bimetallic and trimetallic catalyst.
Ahmad Zamani Ab. Halim
Rusmidah Ali
Wan Azelee Wan Abu Bakar
2014-06-30T07:55:07Z
2014-06-30T07:55:07Z
http://eprints.utm.my/id/eprint/id/eprint/39616
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39616
2014-06-30T07:55:07Z
In-depth of surface properties investigation over ceria based catalyts for carbon dioxide methanation
Rusmidah Ali
2014-06-30T07:55:07Z
2014-06-30T07:55:07Z
http://eprints.utm.my/id/eprint/id/eprint/39617
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39617
2014-06-30T07:55:07Z
Polymolybdate based catalysts in oxidative desulfurization of diesel fuel with TBHPDMF system
Rusmidah Ali
2014-06-23T08:34:49Z
2017-06-22T01:56:02Z
http://eprints.utm.my/id/eprint/id/eprint/38992
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38992
2014-06-23T08:34:49Z
Neutron activation analysis absolute method at Puspati triga mark II research reactor for elemental analysis
This research aimed to study the capability of the neutron activation analysis absolute method by using PUSPATI TRIGA Mark II research reactor, at the Malaysia Nuclear Agency (NM). Most of the quantitative measurements of neutron activation analysis (NAA) were done through comparative method, which was found to have high degree of errors due to the differences in the matrix. NAA based on absolute method is a more direct analysis of the irradiated samples based on (n, ?) reaction rate without using any standard or comparator. In this study the reaction rate of (n, ?) was adopted based on the Høgdahl conventions as well as Westcott formalism. This technique requires absolute gamma ray measurements and neutron spectrum parameters for the calculation of weights or concentrations of elements present in the sample. The neutron spectrum parameters such as epithermal neutron flux shape factor (a), thermal to epithermal neutron flux ratio (f), and thermal and epithermal neutron flux (fth and fepi) were determined at 40 irradiation positions of the rotary rack (RR) as well as at one location of pneumatic transfer system (PTS). The value of a in 40 RR was found to be in the range of 0.0060 to 0.1170 with an average of 0.0172 and 0.0028 at PTS. The f parameter ranged from 14.74 to 30.26 with an average value of 19.00 at 40 RR, while at PTS the value was 15.00. The results of fth and fepi at 40 RR were found to be in the range from 0.87 × 1012 to 2.55 × 1012 n cm-2 s-1 and from 0.41 × 1011 to 1.37 × 1011 n cm-2 s-1, respectively. The average values of fth and fepi were 2.17 × 1012 n cm-2s-1 and 1.16 × 1011 n cm-2 s-1 respectively, and at PTS with value of 3.89 × 1012 n cm-2 s-1 for fth and 2.59 × 1011 n cm-2s-1 for fepi. In addition, the spectral index parameter ( r ?? ? Tn /T0 ) was determined at 40 RR and PTS based on Westcott formalism. The average value was found as 0.0550 at RR and 0.0493 at PTS. The accuracy and precision of the proposed method were investigated by analyzing CRMs Soil-7, SL-1, IAEA-313, IAEA-312, NBS 1633A, USGS STM-1 and MAG-1 standard samples. The results showed a good agreement with the values reported in certificate with Z-score within 0< |Z|<2. Moreover, CRMs Soil-7, NBS 1633A and MAG-1 were analysed for relative method, and the results were found to be in good agreement with certified values. However, the results were slightly less than the results obtained by absolute method. Finally, the absolute NAA method was applied to determine the elemental concentration of U, Th and rare earth elements in rock samples based on Høgdahl convention except for Eu and Lu which were determined based on Westcott formalism. All samples were also analysed using relative method for comparison with the results obtained by absolute method. The deviations of both methods in most cases were found to be less than 10%.
Ibrahim Alfadil Alnour Ishag
2014-06-23T08:33:31Z
2017-06-21T01:50:13Z
http://eprints.utm.my/id/eprint/id/eprint/38972
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38972
2014-06-23T08:33:31Z
Fuzzy ideals in ordered semigroups and their generalisations
The idea of fuzzy sets has opened a new era of research in the world of contemporary mathematics. The proposed concept of fuzzy sets provided for a renewed approach to model imprecision and uncertainty present in phenomena without sharp boundaries. The fuzzification of algebraic structures, particularly ordered semigroups, playa prominent role in mathematics with diverse applications in many applied branches such as computer arithmetic, control engineering, errorcorrecting codes and formal languages. In this background, many researchers initiated the notion of "quasi coincident with" (q) relation between a fuzzy point and a fuzzy set in ordered semigroups. Later a new generalisation of quasi-coincident with relation symbolised as qk where kЄ [0,1) has been introduced. In this thesis, new concepts including fuzzy ideals, fuzzy interior ideals, fuzzy generalised bi-ideals, fuzzy bi-ideals and fuzzy quasi-ideals of type (Є, Є vqk) of ordered semigroup are introduced. Further, ordinary ideals and (Є, Є vqk)-fuzzy ideals are linked using level subset and characteristic function. The results show that in regular, intra-regular and semisimple ordered semigroups both (Є, Є vqk)-fuzzy ideals and (Є, Є vqk)fuzzy interior ideals coincide. The concept of upper/lower parts of (Є, Є vqk)-fuzzy interior ideals is also introduced and furthermore, semisimple, simple and intraregular ordered semi groups are characterised in terms of this notion. The relation between generalised bi-ideals and (Є, Є vqk)-fuzzy generalised bi-ideals is determined. Furthermore, the conditions for the lower part of (Є, Є vqk ) -fuzzy generalised bi-ideal to be a constant function are provided. The characterisations of ordered semigroups by the properties of semiprime (Є, Є vqk) -fuzzy quasi-ideals are investigated. Finally, the classification of ordered semigroups by (Єy,Єy vqg)- fuzzy interior ideals and (Єy , Єy Vqg) -fuzzy interior ideals are determined comprehensively.
Faiz Muhammad Khan
2014-06-18T00:47:07Z
2014-06-18T00:47:07Z
http://eprints.utm.my/id/eprint/id/eprint/39085
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/39085
2014-06-18T00:47:07Z
Toric varieties in the construction of bézout matrix
Nor'aini Aris
2014-06-11T06:53:40Z
2017-09-11T00:26:22Z
http://eprints.utm.my/id/eprint/id/eprint/33306
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33306
2014-06-11T06:53:40Z
VIM and FDM for solving boltzmann equation of self-gravitating gas-dust system
In this research, Boltzmann equation of Self-Gravitating Gas-Dust System is introduced. The model consists of dust component equations, gas dynamics equations and also Poisson equation. The mathematical model is used in order to visualize the movement of the gas and dust in environment. This research only focuses on sequential algorithm and solving the model in 2 Dimension (2-D). Numerical solutions obtained by using the Variational Iteration Method (VIM) and Finite Difference Method (FDM). The results are computed by using Borland C++ Builder, MATLAB 2008a and MAPLE 13. Then, the graphs are visualized by using Microsoft excel. The result is based on numerical analysis. Numerical analysis under consideration is pattern of the graph, gradient of the graph, time execution and computational complexity. The movement of the gas-dust showed differently with the different method. At the end, the results show that the VIM and FDM are successfully in visualizing the movement of the gas-dust in reality. Based on theoretically, VIM is in solving gas-dust problem compared to FDM
Nor Aziran Awang
2014-06-04T00:59:02Z
2017-07-23T04:14:33Z
http://eprints.utm.my/id/eprint/id/eprint/38868
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38868
2014-06-04T00:59:02Z
Nickel and cobalt oxides based catalysts for the methanation reaction
The presence of acidic and toxic gases of carbon dioxide (CO2) and hydrogen sulphide (H2S) will lead to the corrosion in natural gas pipeline system and material in processing plant. Alternatively, CO2 and H2S can be removed using green technology via catalytic methanation reaction by converting CO2 to methane (CH4) gas. Nickel (Ni) and cobalt (Co) oxides are well known catalysts to exhibit higher activity however they are easily deactivated. It is essential to activate these catalysts by incorporating dopants to enhance the catalytic performance. So far, the alteration of these oxides catalysts by adding zirconium, cerium and samarium dopants did not boost up the activity. In this research, a series of alumina (Al2O3) supported Ni/Co oxides based catalysts doped with manganese (Mn) and noble metal oxides such as ruthenium (Ru) and palladium (Pd) were prepared by wetness impregnation method followed by calcination. Various parameters were studied in this research include compositions of catalyst, calcination temperatures, effect of H2S gas, different Mn precursors, effect of sonication, two series furnace testing, reproducibility and stability testing towards CO2/H2 methanation reaction. The catalysts were subjected to characterization process using various techniques such as XRD, FESEM-EDX, Nitrogen Adsorption, TGA-DTG and FTIR in order to study their physical properties. XRD diffractogram illustrated that the supported catalysts were in amorphous state at 1000°C calcination temperature and became crystalline at 1100°C. FESEM micrographs showed that both fresh and used catalysts have spherical shape with small particle sizes in agglomerated and aggregated mixtures. Elemental analysis performed by EDX confirmed the presence of Al, O, Ni, Co, Mn and Ru on the catalysts. Nitrogen Adsorption analysis revealed that both catalysts were in mesoporous structures with BET surface area in the range of 46-60 m2/g. The prepared catalysts were subjected to catalytic screening using micro reactor coupled with FTIR to study the performance of the catalysts by determining the percentage of CO2 conversion, meanwhile the percentage of CH4 formation was analyzed using GC. For nickel based catalyst, Ru/Mn/Ni(5:35:60)/Al2O3 calcined at 1000°C was found to be the potential catalyst which gave 99.74% of CO2 conversion and 72.4% of CH4 formation at the maximum reaction temperature of 400°C. This catalyst can be reused for seven recycles without treatment. Meanwhile, for cobalt oxide based catalyst, Ru/Mn/Co(5:40:55)/Al2O3 calcined at 1000°C was found to be the most potential catalyst which gave 96% of CO2 conversion at low reaction temperature of 250°C with 76% of CH4 formation. This catalyst can be reused for three recycles without treatment. In the presence of H2S, the CO2 conversion exhibited very low conversion to CH4 for both Ru/Mn/Ni(5:35:60)/Al2O3 and Ru/Mn/Co(5:40:55)/Al2O3 catalysts.
Nurul Shafeeqa Mohammad
2014-06-04T00:45:45Z
2020-03-11T06:42:36Z
http://eprints.utm.my/id/eprint/id/eprint/38879
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38879
2014-06-04T00:45:45Z
New sol-gel silica-based hybrid materials and their applications in the analysis of organophosphorus pesticides in various matrices
Commercial sorbent materials are based on polymeric materials and are normally designed to extract polar or non-polar analytes separately and are expensive. In the current work, these problems were addressed through the development of three new in-house sol-gel hybrid organic-inorganic materials which have become important materials for the analysis of organic pollutants residues. Two of these new sol-gel hybrid organic-inorganic materials were synthesized, characterized and used as sorbents for two sample preparations techniques namely, stir bar sorptive extraction (SBSE) and solid phase extraction (SPE). Their extraction performances were evaluated for extraction of selected organophosphorus pesticides (OPPs) in water, fruit and vegetable samples. The first material, 3-(2-aminoethylamino) propyltrimethoxysilane-polydimethylsiloxane, was synthesized as SBSE sorbent and combined with high performance liquid chromatography with ultraviolet detector. Both polar and non-polar OPPs were extracted simultaneously using the new sorbent and it showed high selectivity for the OPPs as compared to commercial polydimethylsiloxane (PDMS) Twister™ SBSE sorbent. The second new sol-gel hybrid material synthesized, methyltrimethoxysilane-cyanopropyl-triethoxysilane, was used as SPE sorbent for OPPs extractions prior to gas chromatography-mass spectrometry analysis. This new sol-gel hybrid sorbent showed lower detection limits (10-70 pg mL-1) and excellent recoveries (94.93-99.98%) against commercial C18 SPE sorbent (0.05-1.23 ng mL-1). Parameters affecting sol-gel process were optimized for each sorbent material to obtain the most efficient sorbent materials and to improve the extraction of the more polar compounds. The third new cyano-based sol-gel hybrid film was synthesized using molecular imprinting (MIP) with methamidophos for sensing OPPs applications in the analysis of vegetable and fruit samples. Low-cost large-scale production, ease of synthesis, and the predictability of specificity by logical design, provide economic advantages which have encouraged researchers to further develop the methodology and applications of MIPs. Cyano-based sol-gel hybrid film act as functional monomers providing more recognition sites through hydrogen bonds with methamidophos for template recognition. The electrochemical behaviour of methamidophos at the sol-gel sensor was characterized by cyclic voltammetry. The results showed that the new method is able to provide a sensitive, anti-interferent and rapid detection of methamidophos in real samples.
Wan Norfazilah Wan Ismail
2014-06-04T00:44:13Z
2017-07-11T01:30:04Z
http://eprints.utm.my/id/eprint/id/eprint/38873
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38873
2014-06-04T00:44:13Z
Experimental-based simulated annealing for job shop scheduling problems with stochastic processing times
Job shop scheduling problem is widely known as one of the most difficult NP-Hard problems to solve and present efforts to solve the problems are mostly expressed in the form of heuristics. This thesis investigates the application of simulated annealing algorithm for solving job shop scheduling problem with stochastic processing times. Schedule quality is assessed based on the distribution of the schedule makespan, which is the maximum completion time of all jobs. The main idea is the integration of simulation into the simulated annealing algorithm. As such, variants of simulated annealing procedure for deterministic problems are first analyzed which are then extended to stochastic versions by incorporating simulation to evaluate schedules generated by the algorithms. Experimental results show that the stochastic variants provide an efficient tool in incorporating all the available distributional information on the processing times into the scheduling procedure. In addition, incorporating statistical tools such as the sampling methods enhance to certain extend the quality as well as the efficiency of the solutions. The performance of the simulated annealing variants is further investigated when three different temperature functions are proposed. The extensive computational tests and analysis on selected problem instances show the superiority of the proposed algorithms compared to some typical dispatching algorithms in high variability levels. Finally, the correlations between the expected makespan and the a-quantile of makespan are examined. The solutions obtained for low variability levels indicate that the two measures are perfectly correlated, and makespan distributions mostly follow the normal distributions, with few cases where they fail the normality tests. Although only stochastic processing times are considered in this thesis, the formulations and methodology can be extended to handle different objective functions as well as other kinds of uncertainties, such as uncertain arrival times, due dates and the handling of unpredictable machine breakdown and incorporation of new activities.
Rashidah Ahmad
2014-06-04T00:41:48Z
2017-07-25T04:42:02Z
http://eprints.utm.my/id/eprint/id/eprint/38862
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38862
2014-06-04T00:41:48Z
Application of ultrasonic-assisted enzymatic digestion system for digestion of cockles
Sample preparation is the most time consuming part of elemental analysis where homogeneous samples that are almost free from organic matter is necessary. Therefore, preliminary operations such as separation of interferents and preconcentration of the analytes are required prior to analysis. Ultrasonic digestion recently proposed as an efficient method for extraction of trace metals from solid samples. The ultrasonic digestion was optimized by using two parameters whilst another two other parameters were used in enzymatic digestion. Conventional one-variable-at-a-time (OVAT) optimization method was applied to both digestion techniques. Fe and Zn were extracted from the samples and were determined by using flame atomic absorption spectrometry (FAAS).The combination of ultrasonic and enzymatic digestion techniques is known as Ultrasonic-Assisted Enzymatic Digestion (USAED) method. The ultrasonication equipment used was ultrasonic bath. Four parameters studied for optimization were sample mass, sonication time, protease enzyme volume and incubation time. The optimum condition of parameters for sample mass was 0.2 g, sonication time of 30 min whilst for enzyme volume was 1000 µL and for incubation time of 24 hours. For the kinetic study, these reactions had undergone zero order reaction. This USAED method was successfully applied for the digestion and kinetic study of the cockle samples.
Norazah Ahmad
2014-06-04T00:41:47Z
2017-07-06T03:45:44Z
http://eprints.utm.my/id/eprint/id/eprint/38861
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38861
2014-06-04T00:41:47Z
Optical properties and photoluminescence of copper nitride thin film prepared by reactive DC sputtering
This research was conducted to prepare copper nitride thin films on glass substrates by reactive DC sputtering technique using a copper plate and nitrogen gas at 20 Pa as source. The Argon pressure 1x 10-1 mbar and DC voltage of 0.5 kV at room temperature. The deposition time varies from 1.0 hour to 3.5 hours at interval of 0.5 hour. The thickness of films was measured using Ellisopmeter, UV-VIS 3101 Spectrophotometer to measure the optical properties of refractive index,n, transmittance, absorbance and reflectance in the visible light region and the photoluminescence property using Luminescence Spectrometer LS55.The films obtained were yellow to reddish-brown depending on the deposition time. For longer deposition time, the thin films turned thicker reddish-brown colour. Thickness of films obtained were in the range 1219.4 nm to 1227.0 nm and the refractive index, n, was about 3.80, constant for all samples. The transmittance increased but absorbance and reflectance decreased as the thickness increased over the wavelength range.. The avaege optical band gap energy, Eg obtained in range of 1.65 to 1.94 eV. The averange emmission peak for maximum intensity was about 419.0 nm obtained in the photoluminescence emission for all samples. This shows that the luminescence light is that of violet light.
Noor Azizun Mohammed Ariff
2014-06-04T00:41:47Z
2017-06-21T00:36:53Z
http://eprints.utm.my/id/eprint/id/eprint/38860
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38860
2014-06-04T00:41:47Z
Ortho-cresol as indicator for toluene exposure among workers
Toluene is a volatile organic solvent used by most industries and household items such as lacquers, paints, glue and nail polish. Recently, the negative health effects on exposure to toluene have attracted various studies. To combat the negative effects, American Conference of Governmental Industrial Hygienists (ACGIH) had lowered the occupational exposure limit from 100 ppm to 50 ppm of toluene vapour. Therefore, this could be translated into the need for a new, simple and more specific indicator test to monitor the degree of toluene exposure among workers. Reports showed that toluene is transformed into its metabolites once consumed or exposed to it. The qualitative detection of these metabolites therefore can be used as an indicator for toluene exposure. Presently in Malaysia, hippuric acid detected in urine is used as the indicator for the degree of toluene exposure. However, hippuric acid is also influenced by one’s dietary intake like black tea, acidic food and sodium benzoate as in food preservatives. In addition, at low levels of toluene exposure, hippuric acid showed poor correlation and linearity in analysis. Thus, in this study, another metabolite of toluene, ortho-cresol was introduced. It was found that urinary ortho-cresol was more specific and sensitive in monitoring toluene exposure. In this study, the degree of toluene exposure of six workers (real samples) was analyzed using urinary ortho-cresol. The samples, along with standards, were characterized using UV-Vis spectrophotometer. Three samples out of six samples were found to have ortho-cresol concentrations between 3.00 ppm - 3.05 ppm. These concentrations are all above the permitted value of 3.00 ppm. A detector kit which establishes the presence of ortho-cresol in urine was also developed in this study. The kit, which exploits a simple colour test with 0.2 ppm as its lowest limit of detection is indispensible especially to monitor the health of workers that are exposed almost daily to toluene.
Nazirah Said
2014-05-26T00:46:42Z
2017-09-19T04:13:25Z
http://eprints.utm.my/id/eprint/id/eprint/38440
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38440
2014-05-26T00:46:42Z
Synthesis and characterization of several local anaesthetics
Three local anaesthetics, tetracaine, lidocaine and benzocaine were synthesized and characterized. Tetracaine or 2-(diethylamino)ethyl 4-butylaminobenzoate was synthesized using two approaches. The first approach was a direct esterification of 4-butylaminobenzoic acid with 2-(diethylamino)ethanol in the presence of boron trifluoride etherate as catalyst to afford 2-(diethylamino)ethyl 4-butylaminobenzoate. The second approach involved two step reactions. Treatment of 4-butylaminobenzoic acid with ethanol in the presence of boron trifluoride etherate afforded ethyl 4-butylaminobenzoate in the first step, followed by, transesterification of ethyl 4-butylaminobenzoate with 2-(diethylamino)ethanol to afford 2-(diethylamino)ethyl 4-butylaminobenzoate in the second step. Lidocaine or 2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide was synthesized from 2,6-dimethylaniline, a-chloroacetyl chloride, diethylamine, with a-chloro-2,6-dimethylacetanilide being intermediate in the synthesis. Benzocaine or ethyl-4-aminobenzoate was synthesized by Fischer esterification of 4-aminobenzoic acid with absolute ethanol. The intermediates and products were characterized by using infrared (IR), proton nuclear magnetic resonance (1H NMR), and carbon nuclear magnetic resonance (13C NMR) spectroscopies.
Faten Mohammed Hezam Alnadeesh
2014-05-26T00:33:45Z
2017-07-05T01:46:12Z
http://eprints.utm.my/id/eprint/id/eprint/38859
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38859
2014-05-26T00:33:45Z
Optical tweezer induced by microring resonator
Optical tweezer technique for molecular trapping is becoming of increasing importance for numerous biological applications. The main objective of this study was to investigate the dynamical behavior of the optical tweezers signals in microring resonators (MRR). Operating system consists of modified nonlinear adddrop optical filter made of InGaAsP/InP integrated together with a series of nonlinear nanoring resonators. This particular form is known as a PANDA ring resonator. Different models of operating system were designed and optical transfer functions for each model were derived by using Z-transform method. Simulation results were obtained from MATLAB2010a program by using parameters of practical devices. Input signals in the form of dark soliton were generated at center wavelength 1.5 µm with peak intensity 1 W/?m2 and pulse width 50 ps. Radii of rings were set to be R=34 µm, R1=60 nm, R2=60 nm, R3=50 nm and R4=50 nm respectively. Coupling coefficients of the system were chosen to be ?1=0.15, ?2=0.65, ?3=0.5, ?4=0.5, ?5=0.5 and ?6=0.50. Intense output signals in the form of potential well are generated at the intensity of 219.14 W/?m2 and FWHM around 20 nm. Simulated results shows an optical force of 15.83 fN generated from intensity gradient associated with the output signal are calculated for particle of diameter 20 nm. Stiffness at the center of the trap was recorded at 2.23 fN nm-1. This study shows that the model was able to control the dynamical behavior of optical tweezers. Analytical formulation of such system provides the underlying physics of dynamic optical tweezers generation within MRR.
Muhammad Safwan Abd. Aziz
2014-05-25T04:58:43Z
2017-09-26T08:11:13Z
http://eprints.utm.my/id/eprint/id/eprint/38578
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38578
2014-05-25T04:58:43Z
The performance of hybrid arima-garch modeling in forecasting gold price
Gold has been considered a safe return investment because of its characteristic to hedge against inflation. As a result, the models to forecast gold must reflect its structure and pattern. Gold prices follow a natural univariate time series data and one of the methods to forecast gold prices is Box-Jenkins, specifically the autoregressive integrated moving average (ARIMA) models. This is due to its statistical properties, accurate forecasting over a short period of time, ease of implementation and able to handle nonstationary data. Despite the fact that ARIMA is powerful and flexible in forecasting, however it is not able to handle the volatility and nonlinearity that are present in the data series. Previous studies showed that generalized autoregressive conditional heteroskedatic (GARCH) models are used in time series forecasting to handle volatility in the commodity data series including gold prices. Hence, this study investigate the performance of hybridization of potential univariate time series specifically ARIMA models with the superior volatility model, GARCH incorporates with the formula of Box-Cox transformation in analyzing and forecasting gold price. The Box-Cox transformation is used as the data transformation due to its power in normalizing data, stabilizing variance and reducing heteroskedasticity.
There is two-phase procedure in the proposed hybrid model of ARIMA and GARCH. In the first phase, the best of the ARIMA models is used to model the linear data of time series and the residual of this linear model will contain only the nonlinear data. In the second phase, the GARCH is used to model the nonlinear patterns of the residuals. This hybrid model which combines an ARIMA model with GARCH error components is applied to analyze the univariate series and to predict the values of approximation. In this procedure, the error term epsilon(t) of the ARIMA model is said to follow a GARCH process of orders r and s.
The performance of the proposed hybrid model is analyzed by employing similar 40 daily gold price data series used by Asadi et al. (2012), Hadavandi et al. (2010), Khashei et al. (2009) and Khashei et al. (2008). From the plotting in-sample series, the gold price series does not vary in a fixed level which indicates that the series is nonstationary in both mean and variance, exhibits upward and nonseasonal trends which reflect the ARIMA models. The hybridization of ARIMA(1,1,1)-GARCH(0,2) revealed significant result at 1% significance level and satisfied the diagnostic checking including the heteroskedasticity test. The plotting of forecast and actual data exhibited the trend of forecast prices follows closely the actual data including for the simulation part of five days out-sample period. Consequently, the hybrid model of ARIMA(1,1,1)GARCH( 0,2) for the transformed data is given by
y(t)* = 0.274y(t-1)* + 0.726y(t-2)* + epsilon(t) -0.992 epsilon(t-1) , epsilon(t) similar to iid N(0,1)
sigma(2)(t) = 1.16x10(-5) + 1.992 sigma(2)(t-1) -1.025 sigma(2)(t-2)
Empirical results indicate that the proposed hybrid model ARIMA-GARCH has improved the estimating and forecasting accuracy by fivefold compared to the previously selected forecasting method. The findings suggest that combination of ARIMA (powerful and flexibility) and GARCH (strength of models in handling volatility and risk in the data series) have potential to overcome the linear and data limitation in the ARIMA models. Thus, this hybridization of ARIMA-GARCH is a novel and promising approach in gold price modeling and forecasting.
Siti Roslindar Yaziz
Noor Azlinna Azizan
Roslina Zakaria
Maizah Hura Ahmad
2014-05-25T04:58:43Z
2017-09-26T03:47:42Z
http://eprints.utm.my/id/eprint/id/eprint/38580
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38580
2014-05-25T04:58:43Z
Standard errors estimation in the presence of high leverage point and heteroscedastic errors in multiple linear regression
In this study, the Robust Heteroscedastic Consistent Covariance Matrix (RHCCM) was proposed in order to estimate standard errors of regression coefficients in the presence of high leverage points and heteroscedastic errors in multiple linear regression. Robust Heteroscedastic Consistent Covariance Matrix (RHCCM) is the combination of a robust method and Heteroscedasticit Consistent Covariance Matrix (HCCM). The robust method is used to eliminate the effect of high leverage points while HCCM is mainly used to eliminate the effect of heteroscedastic errors. The performance of RHCCM was assessed through an empirical study and compared with results obtained when the original Heteroscedastic Consistent Covariance Matrix was used.
Li Peng Khoo
Robiah Adnan
Maizah Hura Ahmad
2014-05-25T04:58:43Z
2014-05-25T04:58:43Z
http://eprints.utm.my/id/eprint/id/eprint/38589
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38589
2014-05-25T04:58:43Z
Physico-chemical characterization of natural zeolite-iron composite adsorbent for removal of paraquat in water
Zaiton Abdul Majid
2014-05-25T04:56:23Z
2017-09-02T13:33:12Z
http://eprints.utm.my/id/eprint/id/eprint/38666
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38666
2014-05-25T04:56:23Z
Reactive black 5 sorption by ananas comosus leaf powder
Nadirah Ismail
Zaiton Abdul Majid
Azmi Aris
Zaharah Ibrahim
2014-05-20T01:45:29Z
2014-05-20T01:45:29Z
http://eprints.utm.my/id/eprint/id/eprint/38346
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38346
2014-05-20T01:45:29Z
Parameter estimation in the presence of heteroscedastic error and outliers in multiple linear regression
Robiah Adnan
2014-05-20T01:43:25Z
2014-05-20T01:43:25Z
http://eprints.utm.my/id/eprint/id/eprint/38410
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38410
2014-05-20T01:43:25Z
Permodelan ruang keadaan untuk teras reaktor di dalam reaktor air bertekanan
Tahir Ahmad
2014-05-20T01:43:24Z
2014-05-20T01:43:24Z
http://eprints.utm.my/id/eprint/id/eprint/38366
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38366
2014-05-20T01:43:24Z
Pemodelan ruang keadaan sistem pemanas untuk simulasi dan analisis
Tahir Ahmad
2014-05-20T01:43:24Z
2014-05-20T01:43:24Z
http://eprints.utm.my/id/eprint/id/eprint/38369
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38369
2014-05-20T01:43:24Z
Pendekatan Kabur Intuitionistik dalam Penambahbaikan Imej EEG Datar
Tahir Ahmad
2014-05-20T01:43:24Z
2014-05-20T01:43:24Z
http://eprints.utm.my/id/eprint/id/eprint/38385
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/38385
2014-05-20T01:43:24Z
Penyelesaian alternatif bagi sistem linear kabur sepenuhnya
Tahir Ahmad
2014-05-12T04:27:02Z
2017-09-14T04:27:06Z
http://eprints.utm.my/id/eprint/id/eprint/33289
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33289
2014-05-12T04:27:02Z
Spray dried prodigiosin from Serratta Marcescens as a food colorant
Pigments from microorganisms can serve as an alternative source to replace synthetic pigments used in the food industry. Natural pigments have some limitations including solubility, sensitivity and short stability upon exposure to light, pH and high temperature. Thus, encapsulation via spray drying can be employed to enhance the pigment’s properties. In this study, spray-dried microcapsules containing red pigment (prodigiosin) extracted from Serratia marcescens was produced using ?-carrageenan and maltodextrin as encapsulation agents. The effect of spray-drying parameters on the encapsulation yield (EY), particle size, moisture content and colour intensity of the prodigiosin microcapsules at different ratios of prodigiosin/encapsulation agent were studied. The most intense colour was obtained for the 1:1 ratio (volume ratio of prodigiosin in ethyl acetate to ?-carrageenan solution) using 200oC inlet temperature, feed flow rate of 60 m3/h, air pressure of 1.5 bar and feed rate of 3 mL/min. The encapsulated pigment is most stable in powder form at 0°C when stored in the dark, and thus has superior stability compared to pigment in its free form. Characterization of spray-dried prodigiosin using FTIR and FESEM confirmed that the particles were properly coated with encapsulating agents. The morphology showed the particles were regular shaped spheres with mean diameters between 0.5µm and 5µm. Finally, the particles were successfully applied to milk, yogurt and carbonated drinks. The results suggest that the spray-dried prodigiosin can be useful as a food colorant under the above optimum operating conditions.
Shahla Namazkar
2014-04-30T07:59:16Z
2017-07-06T04:07:54Z
http://eprints.utm.my/id/eprint/id/eprint/37799
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/37799
2014-04-30T07:59:16Z
Fundamental properties of copper-doped and co-doped sno2of lithium potassium borate glass exposed to photon below 4gy
The glass samples of composition 10K2CO3 ? (90 ? x) H3BO3 with 10 = x = 30, 20Li2CO3 ? 10K2CO3 ? (70 ? x) H3BO3 ? xCu with 0.05 = x = 1.0 and 20Li2CO3 ? 10K2CO3 ? (69.9 ? x) H3BO3 ? 0.1Cu ? xSnO2 with 0.05 = x = 0.2 have successfully been prepared by melt-quenching technique. The samples were analyzed by X ? ray diffraction spectrometer to confirm that the sample is amorphous. The energy band gap measurements of the glass samples reveal that, introducing copper into lithium borate glass reduce the energy band gap of the samples, while the addition of SnO2 into Cu-doped sample increase the energy band gap. The impact of SnO2 gives an enhancement in the luminescence intensity by almost 3 times when 0.1 mol% SnO2 was added to 0.1 mol% Cu-doped borate glass. The peaks shapes shifted from blue luminescence to blue and green luminescence for Cu-doped and co-doped samples respectively. The thermoluminescence (TL) properties of Cudoped and co-doped with SnO2 glass were investigated in this work. The glow curves position of Cu-doped and co-doped with SnO2 glass were recorded at 205?C and 215?C respectively at a heating rate of 20?Cs?1. In addition, the optimum annealing procedure of Cu-doped and co-doped with SnO2 glass was 20 min at 400 ?C and 30 min at 400?C respectively. The highest TL intensity of Cu-doped sample was recorded at Cu concentration of 0.1 mol%. The highest TL intensity for co-doped with SnO2 glass was observed at SnO2 concentration of 0.1 mol%. The linear relationship of dose?TL intensity was observed for both glass samples for different doses ranging from 0.5 to 4.0 Gy subjected to 6, 10 and 12 MV X-ray photon energies and Co?60 gamma ray. The co-doped with SnO2 glass has always higher TL response compared to Cu-doped glass. The study of fading characteristics shows that co-doped with SnO2 glass has lower fading compared to Cu-doped glass. Reproducibility study of both types of glasses show the thermoluminescence intensity of Cu-doped glass are slowly decreasing about 1.6% with the repeating readout and about 1.3% for co-doped with SnO2. Study on the TLD sensitivity shows that the co-doped with SnO2 glass is almost 6 times more sensitive than the Cudoped glass. The TL sensitivity was found as 75 ?C g?1Gy?1 and 266 ?Cg?1Gy?1 for Cu-doped and co-doped with SnO2 glass respectively. The relative energy response of Cu-doped and co-doped with SnO2 glass have been calculated theoretically for photon energies up to 1.25 MeV and it is found that the theoretical calculations are in good agreement with the experimental results. The average value of activation energy and the average frequency of Cu-doped and co-doped with SnO2 glass are calculated.
Haydar Aboud Namma
2014-04-28T02:01:18Z
2017-09-12T06:43:59Z
http://eprints.utm.my/id/eprint/id/eprint/33295
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33295
2014-04-28T02:01:18Z
A study on the characteristics of rainfall data and its parameter estimates
The modeling of the rainfall process has been of interest in simulation studies to assess its impact in the fields of agriculture, water management and others. The rainfall data series used has been obtained from the Malaysian Drainage and Irrigation Department for a 33 year period from 1975 to 2007. The purpose of this study is to investigate the Tweedie family of distributions and determine the appropriate distribution to model the rainfall data using the parameter estimated. Based on the estimated parameter, it was suggested that the Gamma distribution which is a special case of the Tweedie family of distributions is suitable to model the rainfall data instead of the Poisson-gamma distribution. Consequently, a combination of a first order Markov chain and gamma distribution function is identified to model the rainfall process of occurrence and amount separately on a monthly timescale for the ten selected rain gauge stations across Peninsular Malaysia. These model parameter estimates were obtained using the method of maximum likelihood. Conversely, during the estimation of these model parameters certain general characteristics were revealed. Firstly, the transitional probability of a wet day to a wet day was higher but parallel to the transition from a dry day to a wet day. This characteristic revealed the linear relationship between the transitional probabilities and the monthly fraction of wet days. Secondly, the parameter in the gamma distribution functions used to describe the amount of rainfall, is related to the monthly amount of rain per wet day. Therefore, a short method is proposed using the regression technique to estimate the model parameters from these monthly summaries. The relative error analysis revealed that there was no significant difference between the long and short method parameter estimates. Hence, this short method would be very useful in cases where there is a lack of detailed daily rainfall data available.
Jayanti Arumugam
2014-04-14T04:35:16Z
2017-09-27T03:29:54Z
http://eprints.utm.my/id/eprint/id/eprint/37604
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/37604
2014-04-14T04:35:16Z
Effect of MHD on unsteady boundary layer flow past a sphere
Magnetohydrodynamics (MHD) is a field of study which dealing with understanding the dynamic of fluid under the influence of magnetic presence. The effect of MHD in a fluid flow has the potential in controlling the separation of flow, optimizing the heat transfer involved or manipulate the velocity of fluid flow. In this paper, the separation times and flow characteristics of a viscous fluid flow past a sphere are investigated in the presence of magnetic field. In order to solve this problem, the dimensional equations that govern the fluid flow and heat transfer are transformed into dimensionless equations by using appropriate dimensionless variables. The stream functions are introduced to connect and thus having a function that can represent both velocity u and v. Similarity variables are used to deduce the dimensionless governing equations into a system of nonlinear partial differential equations. This system of equations is solved numerically by using numerical scheme known as the Keller-Box method. The results attained are presented graphically and in tabular form.
Nurul Farahain Mohammad
Abdul Rahman Mohd. Kasim
Anati Ali
Sharidan Shafie
2014-04-14T04:30:56Z
2017-09-28T02:34:50Z
http://eprints.utm.my/id/eprint/id/eprint/37759
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/37759
2014-04-14T04:30:56Z
Fuzzy delay differential equation in predator-prey intteraction: analysis of stability of steady state
In this paper, a fuzzy delay predator-prey (FDPP) system is proposed by adopting fuzzy parameter in a delay predator-prey (DPP) system. The steady state and linear stability of FDPP system are determined and analyzed. Here, we show that the trivial steady state is unstable for all value of delays. Mean while the semi trivial steady state is locally asymptotically stable for all values of delays under certain conditions. We prove that the steady state are fuzzy numbers. Several examples are considered to show the results.
Normah Maan
Khabat Barzinji
Nor’aini Aris
2014-03-25T01:48:21Z
2017-09-26T01:40:03Z
http://eprints.utm.my/id/eprint/id/eprint/37239
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/37239
2014-03-25T01:48:21Z
An improved parameter estimation of bass model for forecasting new car demand
A new product forecasting model for new Proton car is developed and tested empirically against the data gathered from the first twelve months of launching. The basic assumption to this model is the innovators who make decision to purchase the new car based on the information obtained from the mass media and the imitators are those who make decision to buy based on the existing social system through the personal selling and advertising. Forecasting new product or service is a critical process in marketing strategies and product performance for an organisation. This proposed Bass diffusion model represent the level of spread on the new car among a given set of the society in terms of a simple mathematical function that elapsed since the introduction of the new product. We highlight the selection of analogy product and selection of parameter estimation method. Results obtained by applying the proposed model and numerical calculation shows that the proposed model is robust and effective for forecasting demand of new product. This study concludes that the newly developed bass diffusion for forecasting new car demand has significantly contributed towards forecasting the diffusion of other new products.
Zuhaimy Ismail
Noratikah Abu
2014-03-25T01:48:21Z
2014-03-25T01:48:21Z
http://eprints.utm.my/id/eprint/id/eprint/37255
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/37255
2014-03-25T01:48:21Z
Analisis masa pemisahan bagi aliran olakan campuran MHD tak tetap merentasi sfera
Anati Ali
2014-03-20T01:20:21Z
2017-09-17T01:27:09Z
http://eprints.utm.my/id/eprint/id/eprint/34646
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/34646
2014-03-20T01:20:21Z
Modelling of blood flow as extended korteweg-de vries and extended korteweg-de vries burgers equation
Blood is made of four components which are plasma, red blood cells, white blood cells and platelets. Many researchers have considered blood as an ideal fluid and the artery as an elastic tube. Due to complexity of blood deformation, a mathematical description of blood itself has not yet been completely formulated. In this research, we shall consider blood flow in an elastic artery. Our main focus is to model blood flow as KdV and KdVB type equations by using the governing equations and asymptotic series method. Specifically these equations are called the extended KdV (eKdV) and the extended KdVB (eKdVB). The hyperbolic tangent method is used in order to obtain the progressive wave solutions. It is found that for extended KdV equation, when there is no tapering(0)a=, the blood flow follows the KdV model.
Siti Sarahanim Saad
2014-03-16T00:53:05Z
2017-07-05T04:14:05Z
http://eprints.utm.my/id/eprint/id/eprint/35873
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/35873
2014-03-16T00:53:05Z
Numerical experiment of radiation self-absorption and radiation dynamics in the dense plasma focus using Lee model
Radial dynamics and plasma focus pinch were influenced in slow compression mode by optically thick plasma due to radiation self-absorption. In this study, the role of radiation self-absorption in Mather type dense plasma focus (DPF) device was investigated. The impact of opacity in slow compression phase and the behaviour of optically thick plasma towards radiation emission were explored. The numerical modelling of self-absorption effect on radiation dynamics, focusing, cooling, collapse and influence of self-absorption on the radiation emission was performed. Lee Model was used for numerical simulation. The model was developed incorporating the various energy balances including thermodynamics, kinematics, radiation dynamics and was capable of yielding the plasma structure and trajectories. The snowplow model describes the axial rundown phase and slug model in radial phase of pinch. Numerical simulations were performed for the absorption of radiation within dense and optically thick plasma. It was found that a steady state pinch with constant radius was only possible at the Pease–Braginskii (PB) current of 1.2 to 1.6 MA for hydrogen and deuterium DPF. For lower and higher values of input current as compared to PB current, the pinch expands and collapses respectively. This current was reduced for heavier gases like Neon (Ne), Argon (Ar), Krypton (Kr) and Xenon (Xe) due to the emission of significant amount of line radiation. For Ne, Ar, Kr and Xe gases with different DPF configurations more severe radiative collapse was observed as compared without the self-absorption factor. It was found that for Ar with no self-absorption, the pinch boundary collapsed in only a few nanoseconds to the radius of 0.1 mm set as cut-off in the model. The pinch does not attain the cut-off radius with self-absorption. In the case of Ne, there was no radiative collapse with self-absorption factor but radiative collapse occurs without self-absorption. A severe radiative collapse was also observed in both cases of Kr and Xe. It was inferred that the pinch radius collapses less when self-absorption was taken into account. The plasma opacity reduces the amount of radiation loss. Thus, self-absorption phenomenon was significant during the slow compression phase and needs to be considered in the design of a new DPF device.
Zahra Ali
2014-03-03T07:27:54Z
2014-05-05T04:50:10Z
http://eprints.utm.my/id/eprint/id/eprint/36804
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36804
2014-03-03T07:27:54Z
Fundamental properties of copper-doped and co-doped SnO2 of lithium potassium borate glass exposed to photon below 4GY
Haydar Aboud Namma
2014-02-27T05:42:06Z
2017-09-19T03:24:08Z
http://eprints.utm.my/id/eprint/id/eprint/36643
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36643
2014-02-27T05:42:06Z
Boundary integral equation method for conformal mapping of multiply connected regions
This work presents two methods for numerical conformal mappings of unbounded multiply connected regions onto several classes of canonical slit regions. The first method is only limited to conformal mapping of unbounded multiply connected regions onto the first category of Koebe's canonical regions. It is based on three boundary integral equations formed with the classical adjoint Neumann kernel, adjoint generalized Neumann kernel and modified Neumann kernel. These integral equations are constructed from a boundary relationship satisfied by an analytic function on the unbounded multiply connected regions. By adding some normalizing conditions, the integral equations are uniquely solvable. The second method is for numerical conformal mapping and its inverse of unbounded multiply connected regions onto the first, second, third and fourth category of Koebe’s canonical regions. It is based on reformulating the conformal mapping problem as a Riemann-Hilbert problem and an adjoint Riemann-Hilbert problem. Two integral equations formed with the adjoint generalized Neumann kernel are constructed. With some normalizing conditions, the integral equations are uniquely solvable. For both methods, discretizing the integral equations with their normalizing conditions lead to systems of linear algebraic equations which are solved by Gaussion elimination method to obtain the boundary values of the mapping functions. The interior values of the mapping functions are then determined by using Cauchy’s integral formula. Cauchy’s integral formula is also used to approximate the interior values of the inverse mapping functions for the second method. Some numerical examples are presented to illustrate the effectiveness of both methods for computing the conformal mappings of unbounded multiply connected regions.
Arif Asraf Mohd. Yunus
2014-02-27T05:42:06Z
2017-09-19T04:19:08Z
http://eprints.utm.my/id/eprint/id/eprint/36644
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36644
2014-02-27T05:42:06Z
Mathematical modelling of persistent splicing systems in DNA computing
Splicing system is a bio-inspired computational model that interprets the cutting and pasting behavior of DNA molecules in the presence of restriction enzymes. Splicing system is defined under the framework of formal language theory. In this research the relation between different types of splicing systems and languages such as uniform, null-context, permanent, persistent and strictly locally testable languages are investigated. Then, the characteristics of persistent and permanent splicing systems are explored in detail. The interesting point about these two systems is that if restriction enzymes are chosen from actual biological sense, then the resulting systems are often persistent and permanent. Their main feature is that the property of crossing of a site is preserved and consequently, the enzymes cleavage process persists. Some sufficient conditions are provided for splicing systems to be persistent and permanent. New concepts of self-closed, crossingpreserved and extended crossing-preserved are introduced. These new concepts are closely connected to the notions of persistent and permanent systems. Moreover, fuzzy splicing system is introduced as an extension of splicing systems. In fact, by considering the threshold languages generated by fuzzy splicing systems, their computational power is increased. In other words, there are some fuzzy splicing systems that generate non-regular languages, while splicing systems with finite components can only generate regular languages. At the end of this research, a laboratory experiment has been conducted to biologically validate the behavior of persistent splicing systems.
Fariba Karimi
2014-02-27T05:42:06Z
2017-07-18T06:58:13Z
http://eprints.utm.my/id/eprint/id/eprint/36647
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36647
2014-02-27T05:42:06Z
A direct probabilistic global search method for the solution of constrained optimal control problems
This research focuses on the development of a new direct stochastic algorithm to address the global optimization of the constrained optimal control problem where the interaction between state and control variables is governed by a system of ordinary differential equations. The objective of this method is to localize a globally optimal control curve in the feasible control space of the problem in such a way that the performance index attains its minimum value. The stochastic methodology is used on the development of the method. Thus, the resulting method is still effective when the complexity of the arising problems prohibits applying gradient-based methods. In this approach, the aforementioned control problem has first to be transformed into a nonlinear programming problem via a suitable discretization technique. The resulting problem is then solved using a stochastic method called Probabilistic Global Search Johor (PGSJ). The idea underpinning the PGSJ is to intelligently sample among potential solutions while no recombination or mutation operator is used. The sampling procedure is performed in accordance with some probability density functions (pdf) which are first initialized uniformly and then iteratively biased towards a globally optimal solution using the information obtained by evaluating the sampling points. After the PGSJ has been successfully implemented, it is found that it is able to arrive at an acceptable solution of the applied optimal control problems. The algorithm is also furnished with some theoretical supports verifying its convergence in probabilistic sense. In addition, some existing global stochastic methods which are based on using pdf are also applied on the optimal control problems where simulations reveal that the PGSJ method is superior to its competitors in terms of computation time and solution quality. These investigations lead to the extension of PGSJ into PGSJ-LS where LS indicates a line search operator added to the original method. These are then assessed and compared by applying them to a practical problem of controlling avian influenza H5N1 where it is verified that the PGSJ-LS performs slightly better than PGSJ
Akbar Banitalebi Dehkordi
2014-02-27T05:42:06Z
2017-07-18T03:54:27Z
http://eprints.utm.my/id/eprint/id/eprint/36645
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36645
2014-02-27T05:42:06Z
Analytical solutions of dissipative heat transfer on the peristaltic flow of non-newtonian fluids in asymmetric channels
Peristalsis is a natural mechanism responsible for the propulsion and the segmentation of biofluids in living structures, and this mechanism is important due to its efficient pumping characteristics. An essential feature of peristalsis is dissipation, thus dissipative heat transfer must be considered in the propulsion of biofluids. Most biofluids exist with different non-Newtonian fluid characteristics and experimental investigations reveal that the physiological structures are non-uniform with asymmetric peristaltic waves. This research focuses on the development of mathematical models which take into account the dissipative heat transfer on the peristaltic flow of non-Newtonian fluids. The non-Newtonian fluids include Walter’s B, fourth grade and Sisko fluids and the flow have been considered in the horizontal and inclined asymmetric channels. Governing equations are first modeled in the laboratory frame and then transformed into the wave frame. Resulting equations are non-dimensionalized and the nonlinearity has been reduced by adopting the long wavelength and small Reynolds number approximations. Explicit forms of the analytical solutions have been obtained using the regular perturbation method. Influences of various parameters such as velocity slip parameter, Sisko fluid parameter, Brinkman, Eckert, Deborah, Soret and Schmidt numbers on the flow quantities namely velocity, shear stress, pumping, trapping, temperature, concentration and heat transfer coefficients have been investigated. Results show that pumping, trapping and temperature are reduced for increasing velocity slip parameter. Temperature and heat transfer coefficients are increased with the increase of Brinkman, Eckert and Deborah numbers. Concentration decreases with the increase of Brinkman, Soret and Schmidt numbers. Comparative study amongst viscous, shear thinning and shear thickening fluids has also been presented.
Hafiz Obaid Ullah Mehmood
2014-02-27T05:42:06Z
2017-06-29T07:01:54Z
http://eprints.utm.my/id/eprint/id/eprint/36646
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36646
2014-02-27T05:42:06Z
A robust estimation method of location and scale with application in monitoring process variability
This thesis consists of two parts; theoretical and application. The first part proposes the development of a new method for robust estimation of location and scale, in data concentration step (C-step), of the most widely used method known as fast minimum covariance determinant (FMCD). This new method is as effective as FMCD and minimum vector variance (MVV) but with lower computational complexity. In FMCD, the optimality criterion of C-step is still quite cumbersome if the number of variables p is large because of the computation of sample generalized variance. This is the reason why MVV has been introduced. The computational complexity of the C-step in FMCD is of order O(p3 ) while MVV is O(p2 ). This is a significant improvement especially for the case when p is large. In this case, although MVV is faster than FMCD, it is still time consuming. Thus, this is the principal motivation of this thesis, that is, to find another optimal criterion which is of far higher computational efficiency. In this study, two other different optimal criteria which will be able to reduce the running time of C-step is proposed. These criteria are (i) the covariance matrix equality and (ii) index set equality. Both criteria do not require any statistical computations, including the generalized variance in FMCD and vector variance in MVV. Since only a logical test is needed, the computational complexities of the C-step are of order O(p ln p) . The second part is the application of the proposed criteria in robust Phase I operation of multivariate process variability based on individual observations. Besides that, to construct a more sensitive Phase II operation, both Wilks’ W statistic and Djauhari’s F statistic are used. Both statistics have different distributions and is used to measure the effect of an additional observation on covariance structure.
Rohayu Mohd. Salleh
2014-02-27T03:39:47Z
2017-06-22T02:30:43Z
http://eprints.utm.my/id/eprint/id/eprint/36548
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36548
2014-02-27T03:39:47Z
Sistem tempahan makanan dan barang runcit secara atas talian (OoDeli)
Development of information technology has helped the world to achieve advancement. This is because, through the development of information technology can provide such services in the business sector, through the business carried the operators can develop their business activities through online sales. In addition, they can also search for user in a faster way and can increase their daily income quickly. Food and daily goods are a necessity for every human being. Every human being in this world needs to eat to survive. They also need to buy everyday items for their daily needs. However, at present many problems and constraints to be encountered when buying everyday items such constraints in terms of time, travel safety and the difficulty in bringing the goods bought in the supermarket. Thus, the development objective of OoDeli system is to develop an online system for ordering food and groceries to help the problems faced by certain groups. Based on the methodology of the prototype, the system will be developed using the language Visual Basic using ASP.net 2010 aplication and the database using SQL Server 2008 to store information. Outcome of the project is a system that is able to allow customers to buy food and daily goods online.
Abidatul Shakira Kamal
2014-02-24T06:40:54Z
2017-07-24T04:13:47Z
http://eprints.utm.my/id/eprint/id/eprint/32616
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/32616
2014-02-24T06:40:54Z
The nth commutativity degree of nonabelian metabelian groups of order at most 24
A group G is metabelian if and only if there exists an abelian normal subgroup A such that the factor group, G A is abelian. Meanwhile, for any group G, the commutativity degree of a group is the probability that two randomly selected elements of the group commute and denoted as P(G). Furthermore, the nth commutativity degree of a group G is defined as the probability that the nth power of a random element commutes with another random element from the same group, Pn(G). In this research, P(G) and Pn(G) for nonabelian metabelian groups of order up to 24 are computed and presented. The nth commutativity degree of a group are found by using the formula of Pn(G).
Zulezzah Abd. Halim
2014-02-23T05:21:54Z
2017-09-17T01:32:25Z
http://eprints.utm.my/id/eprint/id/eprint/33285
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33285
2014-02-23T05:21:54Z
Slanting EDGE method for modulation transfer function computation of X-Ray system
The edge method is commonly used to determine the modulation transfer function (MTF) of a straight edge image in radiography systems. Measurement of MTF by using slanting edge method is an important way to evaluate the quality of a slanted edge image, as it is difficult to acquire a straight image. Slanted edge image offers more data by reprojection of the data to the slanted line, and gives more points in the edge spread function (ESF). Straight and slanted edge images data were used to measure the ESF, the line spread function (LSF) and the presampled MTF using MATLAB R2011a program. Edge images were taken from a thick lead foil in a conventional radiographic screen-film system, and a , thick aluminium test objects with a thick lead in a Fuji computed radiography (FCR) system. Edge images of lead test devices provide higher MTFs than that of aluminiums. The MTF values of slanted edge images were compared to those obtained by straight edge images for spatial frequency range about . The MTF results of lead test devices for conventional and computed radiographic systems are similar, although the computed system has better MTF for spatial frequencies between and with a very low fluctuation due to the extremely small noise. However, for the conventional system has better and higher MTFs for both straight and slanted images. In the conventional radiographic system, the experimental MTF results are accepted by the method with the mean MTF difference of for the straight (0 degress) and the slanted with (2 degress) of edge images for spatial frequencies between and . On the other hand, the mean MTF difference for the straight (0 degress) and slanted (1 and 2 degress) resultant MTFs in the computed radiographic system are and respectively. The best MTF result was obtained from the slanted edge image (2 degress) in the FCR system.
Farhank Saber Braim
2014-02-23T03:39:13Z
2017-09-20T00:17:55Z
http://eprints.utm.my/id/eprint/id/eprint/33097
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33097
2014-02-23T03:39:13Z
Chemical constituents and antimicroblal activity of two arieties of Etlingera Elatior flowers
Etlingera elatior is synonymous with Phaeomeria speciosa, Alpinia elatior, Elettaria speciosa, Nicolaia elatior and Nicolaia speciosa. The species is native to Peninsular Malaysia and Indonesia. In Malaysia, it is called kantan. The essential oil and phytochemicals of two Etlingera elatior flowers varieties (pink and red flower variety) have been studied. The essential oil of the fresh E. elatior flowers was extracted using the hydrodistillation technique and analysed by Kovats Indices and Gas Chromatography-Mass Spectrometry (GC-MS). Hydrodistillation of E. elatior (pink flower variety) flowers gave 70.63% of essential oil classified as monoterpenes, sesquiterpenes, and oxygenated of monoterpenes and sesquiterpenes derivatives. The major constituent identified in the essential oil is cyclodecane (38.07%). Extraction of the dried flowers was done by soxhlet and cold extraction methods using chloroform and dichloromethane, respectively. Fractionation and purification on the crude extracts using Vacuum Liquid Chromatography (VLC) and Column Chromatography (CC) was successfully isolated ß-sitosterol and a mixture of stigmasterol and ß-sitosterol. Their structures were elucidated by GC, GC-MS, IR, 1H NMR and 13C NMR spectroscopies. The antimicrobial activity of essential oil, crude extracts and ß-sitosterol was carried out using disc diffusion method, Minimum Inhibition Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assay with eight strains of bacteria, Enterococcus faecalis, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus (Gram positive), Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and Pseudomonas putida (Gram negative). Antimicrobial screening showed that the essential oil gave moderate to strong inhibition to most of the bacteria with minimum inhibition concentration between 225-900 µg/mL.
Nurul Iryani Muhamad Azhar
2014-02-23T03:34:15Z
2017-09-14T04:14:59Z
http://eprints.utm.my/id/eprint/id/eprint/33213
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33213
2014-02-23T03:34:15Z
Logical operators and its application in determining vulnerable websites caused by SQL injection among UTM faculty websites
This research identifies the problems caused by SQL Injection Bypassing Login among Universiti Teknologi Malaysia (UTM), Johor Bahru faculty?s websites by applying Logical Operators. Structured Query Language, SQL is some kind of language used to allow users to work on the data stored in a database. SQL Injection is a technique to gain illegal access through the vulnerability of a website. Vulnerability of a website means poorly designed website in performing operation on the database. In order to test the vulnerability of websites, the SQL Injection rule will be created and will be test on Mutillidae website to see the effectiveness of the rule. If the rule is effective enough, those rule will be combined by using logical operators. The combination rule will be tested on UTM faculty?s websites to observe and determine whether the website is vulnerable to the combination rule of SQL Injection or not. If the website can be accessed using this combination rule, conclusion can be made that the website is vulnerable and needs to improve on their website security. Hence, the way to avoid SQL Injection will be recommended.
Nurul Fariha Mokhter
2014-02-23T03:31:25Z
2017-09-20T00:22:19Z
http://eprints.utm.my/id/eprint/id/eprint/33147
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33147
2014-02-23T03:31:25Z
Electrodeposition of carboxylated multiwall carbon nanotubes on graphite reinforcement carbon for voltammetry detection of cadmium
Determination of cadmium ion at trace and sub-trace levels is still challenging due to high cost and limited capability of analytical instrumentation. A simple, low cost, non-toxic graphite reinforcement carbon (GRC) electrode modified with carboxylated multiwall carbon nanotubes (c-MWCNT) was prepared by electrodeposition process and used for the determination of cadmium ions at sub-part per billion (sub-ppb) levels. The study involved investigation of electrochemical performance of GRC with different hardness and size. The carboxylated-functionalized MWCNT was characterized by Fourier Transform Infrared Spectrophotometer (FTIR) and Field Emission Scanning Electron Microscope-Energy Dispersive X-ray analysis (FESEM-EDX). FESEM was also used to investigate the surface morphology of the c-MWCNT/GRC electrode. The newly developed electrode was successfully used for the detection of cadmium ion in 0.04 M Briton Robinson Buffer (BRB) by differential pulse anodic stripping voltammetry (DPASV). Some important operational parameters including pH of the buffer, initial potential, scan rate and accumulation time were optimised. Optimum conditions for the DPASV technique was obtained as follows: initial potential Ei = -1600 mV vs. Ag/AgCl (satd.); scan rate ? = 2 mV per sec.; pH = 5.0; deposition time of 10 sec. Based on the DPASV of cadmium ion peak height at -0.78 V vs. Ag/AgCl (Sat’d), the c-MWCNT was found to enhance the anodic peak current of cadmium ion by a factor of 7 fold compared to that peak produced using a bare GRC electrode. Linear calibration curves were obtained from 1 ppb to 5 ppb with detection limit of 0.004 ppb and limit quantification of 0.012 ppb (R2=0.966) respectively. The results suggest that the newly developed c-MWCNT/GRC has a potential to be a simple, efficient, low cost and disposable electrode system for the determination of cadmium ions at a very low concentration level.
Nurul Farhana Othman
2014-02-23T02:13:01Z
2017-09-11T06:25:19Z
http://eprints.utm.my/id/eprint/id/eprint/33100
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33100
2014-02-23T02:13:01Z
Classification and regression tree in classifying and predicting students' academic performance
In this study, Classification and Regression Tree (CART) is used to classify and predict student who is likely to pass or fail in the final exam of Engineering Statistic course. However, two problems typical surfaced when applying CART algorithm on highly dimensional data: misclassification error and overfitting problem. Thus this research aims to reduce its misclassification error and overfitting problem for better accuracy in prediction and classification. Based on this study, different data proportion such as re-substitution method, hold-out method and 10-fold cross validation method are used for building and evaluating the decision tree. The results are compared in terms of prediction accuracy, sensitivity and specificity as well as tree structures. Based on the results obtained, 10-fold cross validation achieves the highest prediction accuracy (least misclassification error) of 85.11%. Hence, it is selected for further overfitting analysis by conducting error rate plot and cost complexity pruning methods in order to reduce the misclassification error. From the results obtained, the final pruned tree has shown to improve the prediction accuracy (87.23%). We have identified three rules generated from the final tree to identify the relationship of the attributes. Consequently, this study indicates that application of CART algorithm by 10-fold cross validation method can produce a better accuracy in classifying and predicting students? academic performance. In addition, lecturers can use such method to identify students who perform poorly in this course so that actions can be taken to avoid more failures in this course.
Su Juih Ho
2014-02-20T06:51:51Z
2017-09-19T09:50:44Z
http://eprints.utm.my/id/eprint/id/eprint/33230
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33230
2014-02-20T06:51:51Z
Multi solitons solutions of Korteweg de Vries (KdV) equation : six solitons
The Korteweg-de Vries (KdV) equation is a nonlinear partial differential equation has nonlinearity and dispersion effects. The balance between these effects leads to a wave propagation that is soliton solution. It propagates without changing it?s shape. The purpose of this research is to obtain the multi solitons solutions of KdV equation up to six-solitons solutions. The Hirota?s bilinear method will be implemented to find the explicit expression for up to six-solitons solutions of KdV equation. Identification of the phase shift that makes full interactions happens at ??=0 and ??=0 for each multi soliton solution of KdV equation. The Maple computer programming will be used to produce the various interactive graphical outputs for up to six-solitons solutions of KdV equation.
Siti Zarifah Sarif
2014-02-20T02:08:13Z
2017-09-11T06:57:06Z
http://eprints.utm.my/id/eprint/id/eprint/32098
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/32098
2014-02-20T02:08:13Z
Flow in a pipeline with leakage
Leakage in pipelines has always been one of the main problems in pipelines transportation fluid. This fluid leakage can happened without any warning. The leaking of fluid in pipeline can give effects to the economic loss and environmental risk. Therefore, the early detection of leak is a main role in the fluid transportation pipelines. This paper presents a technique for early detection of leak in single pipe. The fluid pressure and flow rate velocity are considered as two dependent variables. The governing equations of transient flow were proposed. The mathematical formulation describes the solution process and then solved by the Method of Characteristics and Finite Different Method (FDM). The simulation of pipeline leakage with the three different diameters has been carried out by Matlab programming to see the behavior of pressure and flow in the upstream head and downstream head when leakage occurs. The results show; flow rate trends at the incoming fluid flow pipelines is not equal to outgoing fluid pipelines when leaking occurs and pressure trend at the incoming fluid also not equal to pressure trend outgoing fluid. These situations are obtained to indicate the early presence of leakage. This method provided a theoretical basis for early recognizing leakage
Siti Nur Haseela Izani
2014-02-20T01:41:27Z
2017-09-12T08:32:46Z
http://eprints.utm.my/id/eprint/id/eprint/31989
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/31989
2014-02-20T01:41:27Z
Design and development of hydroxyapatite/zirconia (HA/ZrO2) scaffold for guided bone regeneration
Highly porous scaffold made of bioceramics such as hydroxyapatite (HA) have been widely investigated for guided bone regeneration, however their inferior mechanical strength limits their clinical use to non load bearing applications. In this study we have synthesised HA/ zirconia (ZrO2) mixtures (5, 10, and 20 wt%) using microwave assisted wet precipitation method. Phase composition and particle morphology of the mixture was studied using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) respectively. Presence of ZrO2 in mixtures was confirmed by the presence of peak at 30.22° in XRD, which increased in intensity as concentration of ZrO2 increased in the mixture. Porous structures were generated by using polymeric sponge burn off method. Solid loading of sponge was optimised to achieve good degree of porosity, pore size and pore interconnectivity. SEM analysis of scaffolds revealed good pore interconnectivity and pore size greater than 200 microns. Scaffolds were dipped in solution of poly-L-lactic acid and HA/ZrO2 prior to the compressive strength measurements. The compressive strength of scaffold increased from 1.73 to 2.47 MPa when ZrO2 content increased from 5% to 20% for 20 wt% solid loading. For 30 wt% solid loading, compressive strength increased from 1.83 to 2.63 MPa as concentration of ZrO2 increased.
Nor Akma Mamat
2014-02-20T01:09:20Z
2017-09-11T00:39:21Z
http://eprints.utm.my/id/eprint/id/eprint/33082
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33082
2014-02-20T01:09:20Z
Application of support vector machine and neural network modeling in the prediction of concentration of dispersed phase outlet in rotating disc contactor (RDC) column
Liquid-liquid extraction is one of the most important separation processes that widely used in industries. Rotating Disc Contactor (RDC) column is one of the liquidliquid extractor. Therefore, the study of liquid-liquid extraction in RDC column has become a very important subject to be discussed not just among the chemical engineers but mathematician as well. This project presents Support Vector Machine (SVM) and Neural Network modeling in the prediction of concentration of dispersed phase outlet in RDC column. SVM is an exciting Machine Learning technique that learns by example to sign labels to object and can be used for regression as well as classification purpose, while Neural Network is widely used as effective approach for handling nonlinear data especially in situations where the physical processes are not fully understood. Both modeling systems offer the potential for a more flexible and less error in forecasting. Thus, it can help to save time and reducing cost in conducting experiments. A Statistica software is utilized to help with the SVM modeling and a Matlab code is produced to run the Neural Network simulation in this project. The mean square error is calculated to compare the result between the two models. The analysis shows that both SVM and Neural Network modeling can predict the concentration of dispersed phase in RDC column but the SVM approach gives better result than the Neural Network approach.
Ezzatul Farhain Azmi
2014-02-19T04:56:53Z
2017-07-24T01:43:28Z
http://eprints.utm.my/id/eprint/id/eprint/33237
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33237
2014-02-19T04:56:53Z
Numerical solution of mass transfer to micropolar fluid flow past a stenosed artery
A study about blood flow behaviour numerically and mathematically becomes invaluable tool in interpreting and analyzing the circulatory system. In this study, a mathematical model of fluid flow and mass transfer past through a stenoses artery is developed. The blood behaves as non-Newtonian fluid. The blood flow is considered to be unsteady, nonlinear, axisymmetric, two-dimensional and fully developed which is described by micropolar fluid. Meanwhile, the arterial wall is considered to be rigid. The geometry of stenosis is given by cosine-shaped plotted using MATLAB programme based on existing coding. The governing equations of the problem consist of continuity equation, momentum equation and convection-diffusion equation that govern mass transport to flow are formulated in cylindrical coordinate system. Then, all of the governing equations are written in dimensionless form by using dimensionless quantities in order to avoid difficulties. A radial coordinate transformation of the governing equation together with the set of initial and boundary are also needed in order to avoid interpolation error during discretization. A numerical technique has been performed in this study. Finite difference method in staggered grid known as Marker and Cell (MAC) method aid by existing MATLAB programme has been selected to solve all the governing equations involced. Successive over relaxive (SOR) method is also proposed in handling the poisson equation for pressure. Finally, two stability restriction which optimized the time step size at each calculation play an important role to limit the numerical computational. As a result, the value of wall shear stress and separation zone for micropolar fluid are lower than Newtonian fluid due to the presence of rotational viscosity. The values of wall shear stress and velocity were highest at around of critical stenotic region. While, the mass concentration were decrease and converge to zero at the arterial wall as the both wall shear stress and axial velocity decrease.
Nursyafiqah A. Samad
2014-02-19T01:15:26Z
2017-07-17T07:31:41Z
http://eprints.utm.my/id/eprint/id/eprint/34630
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/34630
2014-02-19T01:15:26Z
Improved models in fuzzy time series for forecasting
The focus of this research is in the area of fuzzy time series. Such a study is important in order to improve the forecasting performance. The research approach adopted in this thesis includes introducing polynomial fuzzy time series, di�erential fuzzy logic relationships model, multi-layer stock forecasting model, data pre-processing approach, and k-step-ahead forecasting. The �ndings from this research provide evidence that integration of the polynomial concept and non- linear optimization transfer the fuzzy time series to a parametric model. By using polynomial fuzzy time series, 83% of experiments were improved signi�cantly. Di�erential fuzzy logical relationships were de�ned to be used for establishing di�erential fuzzy logical relationship groups. By utilizing di�erential fuzzy time series in Taiwan Capitalization Weighted Stock Index (TAIEX) datasets, 90% of the results were improved and as for enrollment datasets this statistic was 100%. Data pre-processing approach managed to reduce the negative e�ects of noisy data by transforming the data into a new domain. By applying integrated data pre-processing fuzzy time series algorithm to short term load data and TAIEX, the average of Mean Absolute Percentage Errors (MAPEs) and Root Mean Square Errors (RMSEs) were reduced by 12.05 and 1.98, respectively. The multi-layer forecasting model enhances the performance of stock forecast values. Many experiments that were carried out on the forty years' stock data indicated that multi-layer fuzzy time series model could be considered as an advanced model for stock market forecasting. The one-day ahead forecasting was successfully employed to England and France 2006 half-hourly load data. The main conclusion drawn from this study suggests that the proposed methods were accurate compared to their counterparts. In addition, the functionality of the proposed methods was enhanced through the proposed algorithms which were tested to be robust and reliable. All of these �ndings were con�rmed through various tests of the proposed methods on numerous case studies. The thesis also recommends that the fuzzy time series model should be considered in forecasting alongside with classical approaches.
Hossein Javedani Sadaei
2014-02-19T00:25:24Z
2017-09-11T04:26:52Z
http://eprints.utm.my/id/eprint/id/eprint/33110
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33110
2014-02-19T00:25:24Z
Correlation between reflectance and refractive index of different liquids using an optical time domain reflectometer (OTDR)
Recently, the area of measurement and instrumentation and particularly sensor development has undergone fast development. Among the active advancement of sensor based microelectronics development, the optical based sensor has expanded promisingly over these past years due to its key advantages such as compact size, low power consumption, corrosion and electrical spark free which would cause a fire in the explosive environment, electromagnetic interference proof, high sensitivity and large distance between signal detection that is possibility of enabling a long distance measurements. For instance, refractive index sensors have attracted considerable attention in biological and chemical applications. Thus many optical sensors for refractive index (RI) detection have been proposed. Therefore, this research was carried out in order to seek the correlation between reflectance and refractive index of different liquids using an optical time domain reflectometer (OTDR) via single mode fibre (SMF) of 100m length. There are three objectives that are to observe the fluctuation in the fiber end of the five liquids (water, acetic acid, 1-butanol, 1-octyne and ethyl glycol with their corresponding RI are 1.33, 1.337, 1.40, 1.42 and 1.43), to clarify experimentally the correlation between reflectance with RI of the liquids and to analyze the potential of using the OTDR technique for measurement RI of liquids. Each liquid is measured 10 times in order to obtain good average value of reflectance reading under three different pulse widths (20ns, 50ns and 100ns). After completing the data analysis, the fluctuations in reflection readings of the liquids is within 6%. The experimental and simulation curves are similar in trend and the OTDR technique has the potential in measuring RIs of liquids.
Sapull Nizam Hashim
2014-02-18T07:02:48Z
2017-09-17T01:23:29Z
http://eprints.utm.my/id/eprint/id/eprint/33242
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33242
2014-02-18T07:02:48Z
Parameter estimation of box-jenkins model using genetic algorithm
Malaysia is very fortunate to be free from natural disaster such as earth quake, volcano and typhoon. Unfortunately, the most severe natural disaster experiencing in Malaysia is flood. The probability of flood may occur had been increase due to the climate change and global warming that happened in Malaysia throughout the year. One of the major factor that contribute to flood is the heavy rainfall or maximum rainfall. Hence, in this study, mathematical analysis had been performed by studying the rainfall pattern of the past years and predict the future pattern. Ulu Sebol station situated in Johor was chosen as the rainfall data station since Johor is one of the state that experienced the worst flood in the year 2006. Accuracy plays an important role in choosing the forecasting techniques in order to make prediction of the future rainfall data. But, before forecasting can be made, estimation of the model parameter must be done. In this thesis, an approach that combines the Box-Jenkins methodology for ARIMA model and Genetic Algorithm (GA) had been introduced as a new approach in estimating the parameter and forecasting. A total of 127 series of data had been used in this study starting from January 2000 and these data were classified as monthly maximum rainfall data. MINITAB 16 computer package was used in analyzing the data and for the development of Box-Jenkins model. Meanwhile, JAVA was used in estimating the parameter of Box-Jenkins model by using Genetic Algorithm. The accuracy of the results were measured by concerning the minimum Mean Absolute Percentage Error (MAPE). By using MINITAB 16, ARIMA(0,1,1) was chosen as the best model that fits to the data. The best estimate of theta given by MINITAB is � = 0.9857 with MAPE 0.6526. By adopting GA in searching the best parameter value, GA gives an outstanding performance with the best estimate of theta is 0.3427 and MAPE with 0.5416. Hence, Genetic Algorithm was proven to work well in estimating the parameter of Box-Jenkins model.
Nur'afifah Rusdi
2014-02-17T01:24:12Z
2017-08-02T04:32:20Z
http://eprints.utm.my/id/eprint/id/eprint/36378
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36378
2014-02-17T01:24:12Z
An analysis of four variants of splicing system
The theoretical development of splicing system has led to the formulation of new extension of splicing system, namely Yusof-Goode (Y-G) splicing system. This Y-G splicing system, which is associated with Y-G splicing rule, is introduced to show the transparent biological process of DNA splicing. In this paper, a theoretical analysis has been carried out to investigate the similarities and differences between Y-G splicing system with the existing splicing systems namely, Head, Paun and Pixton splicing system in biological point of view.
Yuhani Yusof
Nor Haniza Sarmin
Heng Fong Wan
T. Elizabeth Goode
Muhammad Azrin Ahmad
2014-02-17T00:47:49Z
2017-09-18T01:01:56Z
http://eprints.utm.my/id/eprint/id/eprint/35836
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/35836
2014-02-17T00:47:49Z
Dynamic topological description of brainstorm during epileptic seizure
Electroencephalograph is one of the useful and favoured instruments in diagnosing various brain disorders especially in epilepsy due to its non-invasive characteristic and ability in providing wealthy information about brain functions. At present, a large amount of quantitative methods for extracting “hidden” information which cannot be seen by “naked” eye from an electroencephalogram has been invented by scientist around the world. Among those, Flat Electroencephalography (Flat EEG) is one of the novel methods developed by Fuzzy Research Group (FRG), UTM which has been intended to localize epileptic foci of epilepsy patients. The emergence of this invention has led to the development of several Flat EEG based research (e.g., Non Polar CEEG and Fuzzy Neighborhood Clustering on Flat EEG). The verification of the method has been made via comparison with some substantial clinical results. However, in this thesis, theoretical foundation of the method is justified via the construction of a dynamic mathematical transformation called topological conjugacy whereby isomorphism between dynamics of epileptic seizure and Flat EEG is established. Firstly, these two dynamic events are composed into sets of points. Then, they are forced to be strictly linearly ordered and composed into topological spaces. Subsequently, an isomorphism is constructed between corresponding mathematical structures to show that their properties are preserved and conjugate topologically. The constructed topological conjugacy is generalized into a class of dynamical systems. Within this class of dynamical system, Flat EEG’s flow is shown to be structurally stable. Additionally, topological properties on the event of epileptic seizure and Flat EEG have also been established.
Lit Ken Tan
2014-02-16T07:35:29Z
2017-09-12T08:22:42Z
http://eprints.utm.my/id/eprint/id/eprint/33223
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33223
2014-02-16T07:35:29Z
MHD flow past an impulsively started vertical plate in a rotating fluid
In this research we study the heat and mass transfer for the magnetohydrodynamic (MHD) free convection flow over an impulsively started infinite vertical flat plate in the presence of thermal radiation and thermal diffusion (Soret effect) in a rotating viscous fluid. The governing equations, which are the momentum equation, energy equation and mass equation, are derived by using the conservation law. The governing equations are transformed into non-dimensional forms by using the non-dimensional variables. The exact solutions of the non-dimensional governing equations are obtained with the help of Laplace transform technique. These solutions satisfy all imposed initial and boundary. The numerical results of velocity, temperature, concentration, skin friction, the rate of heat transfer and mass transfer are displayed and analysed through graphs and tables. The results show that with increasing rotation parameter E, the secondary velocity increases whereas primary velocity decreases. The primary velocity and secondary velocity are increased by increasing of Soret number, So but decreased by increasing radiation parameter, R.
Yeou Jiann Lim
2014-02-16T06:55:21Z
2017-09-18T07:26:19Z
http://eprints.utm.my/id/eprint/id/eprint/35866
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/35866
2014-02-16T06:55:21Z
Mathematical modelling in river pollution control
This study is conducted to determine the concentration of coliform bacteria along a river. Coliform bacteria are used as the indicator for the pollution level of a river because its concentration in wastewater discharges is much more compared to the concentration of other microorganisms. A mathematical model based on the convection reaction equation will be developed to determine the concentration of coliform bacteria along a river. Before studying the convection reaction equation, we will study the solutions of the simpler model based on the linear advection equation. The model based on the linear advection equation will be solved analytically using the method of characteristics. The model will also be solved numerically using the first order upwind scheme. The graphical outputs for the solution of the model will be presented using MATLAB. After analysing the linear advection equation, we will move on to the convection reaction equation. This equation will be solved analytically using the method of variable change and integrating factor. Once the equation is solved, the solution is plotted using Maple for an easier analysis of the result. The result suggests that the concentration of coliform bacteria is the highest at the source of wastewater discharges.
Darrel Chia Kee Wee
2014-01-06T04:27:03Z
2017-08-06T07:07:45Z
http://eprints.utm.my/id/eprint/id/eprint/36251
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/36251
2014-01-06T04:27:03Z
The first couse of calculus for science and engineering students
This book consists of eight chapters namely Limits and Continuity, Differentiation, Applications of Differentiation, Integration, Applications of Integration, Further Differentiation and Integration, Improper Integrals and Ordinary Differential Equations. Every chapter consists of introduction, subtopics, quizzes, and exercise, to enhance self learning. All concepts and skills presented for each subtopic were accompanied by detailed explanation, followed by examples and complete solutions. Suitable examples were given and arranged in ascending degree of difficulties so that the basic concepts could be understood clearly. More than 320 solved problems were given to assist the students and provide a better understanding of each topic. Hence, we also provide two different forms of questions which are quizzes and exercise for better self tutoring. Lastly, we also attached the differentiation and integration tables, trigonometric identities and answers to every exercises at the end of this book.
Abd. Wahid Md. Raji
Hamisan Rahmat
Ismail Kamis
Mohd. Nor Mohamad
Chee Tiong Ong
2014-01-05T04:20:24Z
2017-09-11T00:30:48Z
http://eprints.utm.my/id/eprint/id/eprint/33079
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33079
2014-01-05T04:20:24Z
Analysis of teachers' emotions toward their approaches to teching in secondary education by using principal component analysis and cluster analysis
The purpose of this study is to investigate the relationship between teachers’ emotions in teaching and their approaches to teaching in secondary education. The study was conducted among 112 teachers in secondary school by using two different questionnaires which are the Approach to Teaching Inventory and the Emotions in Teaching Inventory. The results suggest that there are significant relationship between teachers’ emotions in teaching and the approaches that they used in teaching and learning process either student-focused approaches or teacher-focused approaches. The data was analyse using Principal Component Analysis and cluster analysis. As a result, we identified that teachers experienced more positive emotions when they used student-focused teaching approaches and more negative emotions when they used teacher-focused teaching approaches.
Noor Ain Azamudin
2013-11-28T10:47:40Z
2017-07-19T07:16:39Z
http://eprints.utm.my/id/eprint/id/eprint/33787
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33787
2013-11-28T10:47:40Z
Flood frequency analysis using PL-moments approach
Estimation of flood magnitude is a crucial component in planning, designing, and managing of water resources projects. Flood frequency analysis (FFA) provides a practical means of determining a robust probability distribution that fits streamflow data at a location of interest. The main focus in hydrology design is the estimation of high flow quantile. L-moments, popular among hydrologist in FFA is known to be oversensitive towards the lower part of the distribution and give insufficient weight to large sample values. As an alternative, the method of partial L-moments (PLmoments) is proposed to give weightage to the upper part of distribution and large values in censored sample. The aim of this study is to compare the performance of PL-moments and L-moments in FFA. The method of PL-moments was developed for generalized extreme value (GEV), generalized logistic (GLO), generalized pareto (GPA), extreme value type 1 (EV1) and logistic (LOG) distributions. Monte Carlo simulations from population distributions of known and unknown samples were conducted to assess the performance of PL-moments compared to L-moments. Simulation results showed that PL-moments give comparable and slightly better parameter estimates than those by L-moments particularly when estimating the high flow quantiles. In regional flood frequency analysis, new statistical tests based on PL-moments were developed to measure discordancy, regional homogeneity and identify a best regional distribution. The quantile estimates based on the regional distribution using PL-moments are more efficient than L-moments in estimating flood quantiles at higher return periods. The overall results strongly support that PLmoments method would improve the flood quantiles estimation particularly for higher quantiles and thus serves as a useful tool for application in flood frequency analysis.
Zahrahtul Amani Zakaria
2013-11-28T10:47:23Z
2017-07-23T01:30:35Z
http://eprints.utm.my/id/eprint/id/eprint/33758
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33758
2013-11-28T10:47:23Z
A new statistic to the theory of correlation stability testing in financial market
Testing the stability of correlation structures is an active research area involving the applications of multivariate analysis in financial market such as stock market analysis, risk management, market equity, general financial and economic studies, and real estates. In the financial market, the number of variable p is usually large and might reach thousands. As a consequence, the standard stability test Box’s M and Jennrich’s statistic are not capable to handle it. This condition makes the computation of the statistical tests quite cumbersome and tedious because the computational efficiency of finding the determinant and inverse of the correlation matrix becomes low. In order to solve these problems, this thesis introduces T*-statistic for testing the stability of correlation structure in an independent sequence of sample correlation matrices from a p-variate normal distribution based on a repeated test approach. For this purpose, the asymptotic distribution of the test under the null hypothesis is derived mathematically using the vec operator and commutation matrix. The power of T*-statistic is computed and compared with existing ones under certain conditions of the alternative hypothesis. It is found that, if p is large, then the power of T*-statistic dominates the power of the J-statistic for all shifts. On the other hand, when the shift is small, its power is equal to that the Mstatistic. The second problem is to diagnose and find an explanation when the null hypothesis is rejected. For that purpose, by considering correlation matrix as representing a complex network, network topology approach is used to demonstrate to what extent that two or more correlation structures are different from each other. To interpret the filtered network topology, four popular centrality measures have been used. Moreover, to enrich the economic interpretation, average of weights is introduced as another measure of centrality.
Shamshuritawati Sharif
2013-11-28T10:47:08Z
2017-07-23T01:17:19Z
http://eprints.utm.my/id/eprint/id/eprint/33813
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33813
2013-11-28T10:47:08Z
Optimal control based on nonlinear conjugate gradient method in cardiac electrophysiology
Sudden cardiac death is often attributed to cardiac arrhythmia, the situation when normal heart rhythm is disordered. In the context of optimal control of cardiac arrhythmia, it is essential to determine the optimal current required to be injected to the patient for dampening the excitation wavefront propagation resulting from cardiac arrhythmia, in which this process is known as defibrillation. Consequently, this leads to an optimization problem arising from cardiac electrophysiology, namely Optimal Control Problem of Monodomain Model (OCPMM). The OCPMM is a nonlinear programming problem that is constrained by parabolic partial differential equation coupled to a system of nonlinear ordinary differential equations, which turned out to be computationally demanding. The main aim of this research is on discovering more efficient optimization methods for solving OCPMM. First, the original complex problem is decomposed into sub-problems through the operator splitting technique for reducing the complexity of OCPMM. Next, the classical, modified and hybrid nonlinear conjugate gradient methods are employed to solve the split and discretized OCPMM. Numerical results prove that the modified method, namely the variant of the Dai-Yuan (VDY) method as well as the new developed hybrid method, namely the hybrid Ng-Rohanin (hNR) method are very efficient in solving OCPMM. Besides that, this research also studies the effects of control domain on OCPMM using two recognized factors, which are the position and the size. Numerical findings indicate that the control domains should consist of small size domains and located near to the excitation domain, for achieving better defibrillation performance. Lastly, based on the observed effects, an ideal control domain is proposed. Numerical results show that lowest current as well as shortest time are required by the ideal control domain during the defibrillation process. As a conclusion, the ideal control domain is capable of ensuring an efficient and successful defibrillation process.
Kin Wei Ng
2013-11-28T10:46:57Z
2017-07-13T00:47:55Z
http://eprints.utm.my/id/eprint/id/eprint/33812
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33812
2013-11-28T10:46:57Z
One dimensional solute transport in homogeneous porous domain
Analytical solutions are obtained for dispersion of pollutants along groundwater flow in a longitudinal direction through semi-infinite aquifers which is porous. The solute dispersion is considered temporally dependent while the seepage velocity uniform. The dependency of the solute dispersion to time will indicate that the solute dispersion will change in certain times as the groundwater’s parameters change due to monsoon season and in normal season. Analytical solutions are obtained for uniform pulse type input point source. The Laplace transformation technique is employed to get the analytical solutions of the present problem. The solutions obtained predict the time and distance from the location at which an input concentration is introduced at which the pollution concentration becomes harmless.
Noorellimia Mat Toridi
2013-11-28T10:46:55Z
2017-07-19T06:50:48Z
http://eprints.utm.my/id/eprint/id/eprint/33855
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33855
2013-11-28T10:46:55Z
Unsteady magnetohydrodynamics flow of a micropolar fluid with heat and mass transfer
The unsteady boundary layer flow has become of great interest in the field of fluid mechanics including the area of convective double diffusion. This is due to the complexity of the problem by including extra independent time variable, especially in the study of magnetohydrodynamic flow immersed in a micropolar fluid. In this thesis, the unsteady two-dimensional laminar boundary layer and mixed convection stagnation point flow towards a stretching or shrinking sheet immersed in magnetohydrodynamic micropolar fluid are considered. Specific problems are considered with different effects such as Soret and Dufour effects, thermophoresis effect and slip effect. Along with these effects, the micropolar parameter, the magnetic parameter and the suction or injection parameter are also considered. The governing non-linear equations are transformed into a system of differential equations by using appropriate non-dimensional variables which are then solved numerically using an implicit finite difference scheme. Numerical results for the skin friction, the Nusselt number and the Sherwood number as well as the velocity, microrotation, temperature and concentration profiles for different physical parameters are presented graphically and in tabular form. The results obtained show that there is a smooth transition from small time solution to large time solution. It is also found that with an increase of Soret and Dufour numbers, the momentum boundary layer thickness increases whereas the microrotation boundary layer thickness decreases for assisting flow while a reverse trend is observed for opposing flow. The thermal and concentration boundary layer thicknesses increase in both cases. By increasing the values of the slip parameter, all the boundary layer thicknesses decrease. In addition, by increasing the values of thermophoresis, the concentration boundary layer thickness decreases.
Aurangzaib Mangi
2013-11-28T10:46:53Z
2017-07-19T06:44:52Z
http://eprints.utm.my/id/eprint/id/eprint/33806
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33806
2013-11-28T10:46:53Z
Liquid and solid phase microextraction methods for the analysis of organic environmental pollutants
This work involves the investigation of new approaches and applications in miniaturized sample preparation techniques based on liquid phase and solid phase microextractions. A two-phase hollow fiber liquid phase microextraction (HFLPME) method combined with gas chromatography-mass spectrometry was developed for the determination of selected polycyclic aromatic hydrocarbons (PAHs) in fresh milk. Under optimized conditions, low detection limits (LODs) were obtained ranging from 0.07-1.4 µg L-1 with relative recoveries of 85-110% which were higher than those obtained by conventional solvent extraction for the volatile PAHs. Agarose film liquid phase microextraction (AF-LPME) was developed for the extraction and preconcentration of PAHs in environmental water samples. Agarose, a green polymer, has been manipulated for different microextraction approaches. Agarose film was used as an interface between donor and acceptor phases which allowed for selective extraction of the analytes under optimum conditions. Under the optimum extraction conditions, the method showed good linearity in the range of 0.1–200 µg L-1, low limits of detection (0.01-0.04 µg L-1) and satisfactory relative recoveries (92.9-104.7%). AF-LPME device proved to be low-cost and thus reuse or recycle of the film was not required to eliminate the analytes carry-over between runs. A new microextraction technique termed agarose gel liquid phase microextraction (AG-LPME) was developed for the extraction of PAHs in water. Solvent-impregnated agarose gel disc used in AG-LPME was prepared by slicing gelled agarose and exchanging the solvent from water to ethanol and then to 1- octanol that functioned as the extractant and impregnation solvent. The solvent impregnated AG-LPME was found to be comparable with HF-LPME in terms of extraction efficiencies without solvent dissolution problems observed. The method offered high enrichment factors in the range of 89-177 and trace level LODs in the range of 9-14 ng L-1. This technique combines extraction and preconcentration approaches using an environmentally-compatible solvent holder that fulfils the green chemistry concept. Due to the hydrophilic property of agarose, the selectivity of AGLPME was evaluated on hydrophilic triazine herbicides. The AG-LPME showed significantly higher extraction efficiencies as compared to HF-LPME. The method offered superior enrichment factors in the range of 115-300 and trace LODs in the range of 0.02-0.04 µg L-1. Multi-walled carbon nanotube-impregnated agarose film microextraction (MWCNT-AFME) combined with micro high performance liquid chromatography–ultraviolet detection has also been developed. The method utilized MWCNTs immobilized in agarose film which served as the adsorbent holder. The technique achieved trace LODs in the range of 0.1-50 ng L-1 for selected PAHs. The new MWCNT-AFME method was successfully applied to the analysis of spiked green tea beverage samples with good relative recoveries. The results supported the feasibility of agarose to serve as adsorbent holder in solid phase microextraction, thus saving the cost of chemical and waste disposal.
Saw Hong Loh
2013-11-28T10:46:46Z
2017-07-18T02:12:13Z
http://eprints.utm.my/id/eprint/id/eprint/33842
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33842
2013-11-28T10:46:46Z
Synthesis and bioassay studies of cationic porphyrins for gene transfection delivery
Porphyrins are stable aromatic tetrapyrrolic macromolecules found in many natural products such as hemin, chlorophylls and vitamin B12. Interaction ability of cationic porphyrins with nucleic acid and their fluorescent properties for location identification in cellular domain have promoted their uses as potential gene vectors for gene therapy. In this study, basic cationic porphyrins bearing four positive charges were synthesized. Besides, amphiphilic porphyrins anchored with both hydrophobic and hydrophilic moieties were prepared to facilitate membrane penetration and to give a higher cellular uptake. Polyamidoamine(PAMAM)-porphyrin conjugate was also prepared to produce a complex with higher transfection level but with low toxicity. Adler-Longo condensation method was mainly used to synthesize these cationic porphyrin precursors. All cationic porphyrins were obtained in high yield. All of the compounds were characterized using 1H-NMR, 13C-NMR, ultraviolet (UV) and infrared(IR) spectroscopies.Cytotoxicity and cellular uptake of all cationic compounds were tested on Chinese Hamster Ovary (CHO) cells to evaluate their potential uses as gene carriers. Results revealed that all porphyrins show relatively low toxicity towards the cell even at high concentration(100 μM).The 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin and two amphiphilic cationic porphyrins of 5-hexyl-10,15,20-tris(N-methyl-4-pyridyl) porphyrin and 5-propyl-10,15,20-tris(N-methyl-4-pyridyl)porphyrin which contain three positive charges on the periphery show the highest cellular uptake. It was also found that the amphiphilic cis-porphyrins of 5,10-dipropyl-15,20-bis(N-methyl-4-pyridyl)porphyrin and 5,10-dihexyl-15,20-bis(N-methyl-4-pyridyl)porphyrin exhibited higher cellular uptake compared to their trans-isomers, 5,15-dipropyl-10,20-bis(N-methyl-4-pyridyl)porphyrin and 5,15-dihexyl-10,20-bis(N-methyl-4- pyridyl)porphyrin.
Siaw Fui Kiew
2013-11-28T10:46:45Z
2017-07-19T06:41:14Z
http://eprints.utm.my/id/eprint/id/eprint/33782
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33782
2013-11-28T10:46:45Z
Enhanced methods for benchmarking and ranking in data envelopment analysis
Data Envelopment Analysis (DEA) is a non-parametric method in operations research for estimating production frontier, and benchmarking and ranking Decision Making Units (DMUs). The current DEA techniques are not suitable for these assessments, thus, this study proposes novel robust methods to improve the capabilities of DEA for approximating the production frontier while simultaneously benchmarking and ranking DMUs. Firstly, the shortcomings in the DEA techniques are illustrated with several counter examples followed by new proposed methods to remove the shortcomings. Then, the techniques are combined and used in a linear programming model called Kourosh and Arash Model (KAM). KAM estimates the production frontier and allows decisions within the target regions instead of points in the benchmark of DMUs. In this study, KAM produces three efficiency indexes, namely: the lowest, technical and highest efficiency scores for each DMU. These efficiency indexes provide a sensitivity index for each DMU and rank DMUs completely. KAM is also able to measure the efficiency scores of DMUs inclusive of integer and real data. To sum up, the proposed techniques in this study have improved the capabilities of DEA to assess the production frontier, as well as benchmark and rank DMUs.
Dariush Khezrimotlagh
2013-11-28T10:46:37Z
2017-07-18T07:45:28Z
http://eprints.utm.my/id/eprint/id/eprint/33856
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33856
2013-11-28T10:46:37Z
Using reissner-nordstrom solution for modeling epileptic seizures
Modeling of the brainstorm of epileptic seizure is to find and follow paths of clusters of charges carried by ions from epileptic foci to the scalp area of the brain. This will also estimate the location of the epileptic foci or onset of the seizures. The foci may be located in a small volume of brain tissue due to unusually large accumulation of ionic charges. As a seizure begins, the electrostatic repulsive force among these ions throws the ions outward in all directions along 100 billions neurons inside the brain. These charges of electric pulses arrive finally at the scalps, and are recorded as electroencephalography (EEG) voltage signals. Modeling this event poses challenges since seizures might start at other locations at the same instant. Hence, the mixture of paths from different foci is unavoidable which resulted in a very chaotic trace of EEG signals. Sporadic ionic burst of the epileptic brainstorm is very similar to the event of the Big Bang. The tremendous explosion originated from a point of singularity, threw all matters and space outwards, and started the expansion of the universe. The journey of the matters along with this expansion provides a good model for the journey of the charges to the scalp during brainstorm epileptic seizure. General relativity states that the fundamental force of gravitation can be described as a curved space-time caused by the presence of matter and energy. Thus, matters move along this curve space-time, during the expansion of the universe. Likewise, electrostatic field of charges curved space provides path for the charges’ journey during epilepsy attack. Exact solution to the Einstein Field equation of fluid which describes the expansion of the universe may also give exact solution to Einstein field equation of electromagnetic field which describes the path of the ions during epilepsy attack. The electrovacuum solution of Reissner-Nordström metric of a charged, non-rotating black hole is suited to the variables of the model. Results obtained were then compared to another result that was obtained by using pixel image method of flat EEG. The percentage agreement is around 56.3% and was determined by the number of pixel dots that actually resides in the spherical domains of the charges’ paths. Significantly and interestingly enough, 33% of the lengths of the paths are less than 4 mm while 67% are much deeper inside the brain. This value totally agrees with the percentage of folded cortex deep inside the brain and far from the scalp.
Noraini Ismail
2013-11-28T10:46:35Z
2017-07-23T07:17:38Z
http://eprints.utm.my/id/eprint/id/eprint/33848
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33848
2013-11-28T10:46:35Z
The growth mechanism in self-assembly nanostructures of silicon/silicon dioxide interface
Silicon nanodots is a common zero-dimensional nanomaterial investigated for single-electron device applications in integrated circuits. The current study attempts to look into the ever-popular silicon self-assembly nanodot grown on different substrates, with emphasis on its growth theory and characterizations. Discrepancy in its growth theories has led to misunderstanding and therefore innovative approaches are presented in this study to clarify and resolve the existing problems. A radio-frequency magnetron sputtering method was used for Silicon nanodots deposition, with the following conditions: argon gas flow rate 5-10 sccm, substrate temperature between 300-600 ºC, deposition time 7-20 minutes, and radio-frequency power between 100-150 W. This research covers both experimental and simulation works including the classical theory of nucleation. Generally, important parameters were first calculated then simulated using computer programming, and finally matched in order to estimate the values of critical energy ?G*, critical radius r*, surface energy ?, and free energy change per unit area ?Gv. The associated Volmer-Weber growth mode was then predicted. Observably, optimum growth parameters for the inception of silicon nanodots were found to be at 600 ºC/10 minutes/100W formed on corning glass substrate. Structural and optical properties have been characterized using atomic force microscope AFM, energy-dispersive X-ray spectroscopy EDX, X-Ray diffraction XRD, photoluminescence PL and scanning electron microscopy SEM. In addition, the AFM characterization results show the existence of nanodots with the estimated average size of 34.4 nm. The results from PL spectrum reveal the presence of a peak which corresponds to a bandgap energy of 1.80 eV and this was attributed to the quantum confinement of electron–hole pairs in quantum wells. A further confirmation using EDX measurement was made which showed the existence of 0.48 at.% of silicon on the substrate. XRD analysis reveals the crystalline structure for high temperature conditions due to orderly silicon nanodots formed on the substrate. The results proved that the properties of silicon nanodots on quartz SiO2, corning glass (7059) and silicon substrates were strongly dependent on the experimental conditions.
Fatima Aldaw Idrees
2013-11-28T10:46:32Z
2017-09-11T03:48:23Z
http://eprints.utm.my/id/eprint/id/eprint/33839
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33839
2013-11-28T10:46:32Z
Study of floating bodies in wave ny using smoothed particle hydrodynamics (SPH)
One of the problems is the environment area which involves the floating of body with effective microorganism (SM). As a result, we need a detail description as well as calculation of floating body is using finite difference method (FD). However, this method produces low accuracy results. Beside, FD method is based on regular grid problem which is not efficient especially in river layout. In recent years, Smoothed Particle Hydrodynamics (SPH) method is developed to solve mechanical problems as well as fluid flow problems. In order to simulate the floating body problem using irregular grid as well as higher order accuracy, SPH is the suitable method. The advantage of SPH is its meshless technique which avoid the time consuming remeshing process especially in finite element method. The above numerical methods are coded in Fortran program. SPH can be a useful hydrodynamics model for breaking waves and the nearshore zone, particularly for case where spray and splash are important. The advantage of SPH is to be able to accurately model the complex flows associated with breaking water waves, including instantaneous motions as well as (time-averaged) wave-induced flows, such as undertow, longshore currents, and rip currents. The results of the computations show that SPH can be used to simulate free surface flows without difficulty provided the density.
Cheun Yuen Ha
2013-11-28T10:46:22Z
2013-12-18T01:28:17Z
http://eprints.utm.my/id/eprint/id/eprint/33807
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33807
2013-11-28T10:46:22Z
Magnetic field effects on the adsorption of dyes, heterogeneous oxidation catalysis and synthesis of well-aligned titania
Nursyafreena Attan
2013-11-28T10:46:14Z
2017-07-23T06:36:57Z
http://eprints.utm.my/id/eprint/id/eprint/33840
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33840
2013-11-28T10:46:14Z
Subcritical water extraction with compacted natural calcium carbonate column for the extraction of natural products
The aim of this work was to develop subcritical water extraction (SWE) method for the extraction of natural products. The developed system was applied to the extraction of natural products from the rhizomes of A. mutica and Calotropis procera as model samples. The efficiency of the SWE method was compared with Soxhlet extraction method using as model sample in terms of yield amount, extraction time and solvent consumption. The SWE attached with compacted natural calcium carbonate (CNCC) method was found to provide higher yield (49.14%) compared with Soxhlet extraction (33%). Three compounds namely kawain, flavokawain and 1,7-diphenyl-5-hydroxy-6-hepten-3-one (DHH) were extracted from the rhizomes of A. mutica using water as a green solvent employing modified subcritical water extraction technique attached to a CNCC column. The CNCC obtained from sea shells was used as adsorbent material to enhance selectivity and purity of the extract. The extract obtained was used without further purification for quantitative analysis based on standard compounds. In this modified SWE technique, water modified with 6-10% acetonitrile, methanol and ethanol were used as extraction solvent. Dried rhizomes of A. mutica were introduced into the extraction vessel connected to the pump that delivers the extractant which further passes through the CNCC unit. The optimum conditions for this extraction were 160?C as extraction temperature, 7 MPa as extraction pressure, 1.8 mL/min as elution volume flow rate and 30 min as extraction time. It was also noted that 160°C extraction temperature produced reasonable amounts of the products (1.891 g, 54.02%, 1.87 g, 53.42% and 1.63 g, 46.6%) with three modifiers (methanol, acetonitrile and ethanol) under identical optimum conditions. The recoveries of the compounds showed good results especially for kawain. Methanol (10%) achieved high recovery (94.82%) compared to the other modifier ratios. In general, the developed method offers rapid and efficient extraction of natural products with reduced organic solvent usage.
Yousif Jumaa Abdo Alrahman Adam
2013-11-28T10:36:07Z
2017-07-23T01:40:59Z
http://eprints.utm.my/id/eprint/id/eprint/33775
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33775
2013-11-28T10:36:07Z
Commutativity degrees and related invariants of some finite nilpotent groups
In this research, two-generator p-groups of nilpotency class two, which is referred to as G are considered. The commutativity degree of a finite group G, denoted as P?G?, is defined as the probability that a random element of the group G commutes with another random element in G. The main objective of this research is to derive the general formula for P?G? and its generalizations. This research starts by finding the formula for the number of conjugacy classes of G. Then the commutativity degree of each of these groups is determined by using the fact that the commutativity degree of a finite group G is equal to the number of conjugacy classes of G divided by the order of G. The commutativity degree can be generalized to the concepts of n-th commutativity degree, ? ?, n P G which is defined as the probability that the n-th power of a random element commutes with another random element from the same group. Moreover, ? ? n P G can be extended to the relative n-th commutativity degree, ? , ?, n P H G which is the probability of commuting the n-th power of a random element of H with an element of G, where H is a subgroup of G. In this research, the explicit formulas for ? ? n P G and ? , ? n P H G are computed. Meanwhile, another generalization of the commutativity degree, which is called commutator degree and denoted by ? ? g P G , is the probability that the commutator of two elements in G is equal to an element g in G. In this research, an effective character-free method is used for finding the exact formula for ? ?. g P G Finally, the exterior degree of the wreath product of A and B, P^ ?A? B?, is found where A and B are two finite abelian groups.
Fadila Normahia Abd. Manaf
2013-11-20T04:00:22Z
2017-09-13T04:09:17Z
http://eprints.utm.my/id/eprint/id/eprint/33227
This item is in the repository with the URL: http://eprints.utm.my/id/eprint/id/eprint/33227
2013-11-20T04:00:22Z
Modelling and forecasting volatile data by using ARIMA and GARCH models
Modelling and forecasting of volatile data have become the area of interest in financial time series. Volatility refers to a condition where the conditional variance changes between extremely high and extremely low values. In the current study, modelling and forecasting will be carried out using two sets of real data namely crude oil prices and kijang emas prices. The models investigated are Box-Jenkins Autoregressive Integrated Moving Average (ARIMA) model and Generalized Autoregressive Conditionally Heteroscedasticity (GARCH) model. In estimating the parameters for the Box-Jenkins ARIMA model, two estimation methods are used. These are Maximum Likelihood Estimation (MLE) and Ordinary Least Squares Estimation (OLS). The capabilities of these two methods in estimating the ARIMA models are evaluated by using Mean Absolute Percentage Error (MAPE). The modelling performances of ARIMA and GARCH models will be evaluated by using Akaike’s Information Criterion (AIC) while the forecasting performances of both models will be evaluated by using Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE). The processes of modelling and forecasting will be done by using R and Eviews statistical softwares. As a result of the study, it can be concluded that in terms of parameters estimation of ARIMA models, MLE gives more precise forecast for crude oil prices data while OLS gives more precise forecast for kijang emas prices data. In terms of forecasting performances between ARIMA and GARCH models, it can be concluded that GARCH is a better model for kijang emas prices data while ARIMA is a better model for crude oil prices data.
Nor Hamizah Miswan