bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on the Phase Formation of MgxB2 (x=0.8, 1.0, 1.2)
Authors: Mohd Aris Mohd Faizal
Published: October 2017

Phase formation of Magnesium diboride MgxB2 (x=0.8, 1.0, 1.2) by in situ reaction of Magnesium (Mg) and Boron (B) at different annealing temperature by varying the nominal Mg composition was compared. The X-ray difffraction pattern indicates that Magnesium Oxide (MgO) is the major secondary phase. Some unreacted Mg was found for nominally stoichiometric and Mg excess samples annealed at or below 750°C. However, no unreacted Mg was detected by XRD for Mg deficient samples. Scanning Electron microscopy images show the porous nature of synthesised samples.
Half-Sweep Arithmetic Mean Method with High-Order Newton-Cotes Quadrature Schemes to Solve Linear Second Kind Fredholm Equations
Authors: Sundaram Muthuvalu Mohana , Sulaiman Jumat
Published: October 2017

The main purpose of this paper is to examine the effectiveness of the Half-Sweep Arithmetic Mean (HSAM) method in solving the dense linear systems generated from the discretization of the linear Fredholm integral equations of the second kind. In addition, the applications of the various orders of closed Newton-Cotes quadrature discretization schemes will be investigate in order to form linear systems. Furthermore, the basic formulation and implementation for the proposed method are also presented. Some illustrative examples are given to point out the efficiency of the proposed method.
Structural Investigation of Crystalline Host Phosphor Cadmium Tellurite Systems
Authors: Hussin Rosli , Siang Leong Ng , Alias Nur Shahira
Published: October 2017

Generally, the luminescent properties of phosphors are strongly dependent on the crystal structure of the host materials. Finding a stable crystal structure, high physical and chemical stability of crystalline matrix is still a critical step to obtain rare-earth ions or transition metal ions-doped persistent phosphor with excellent properties. The glassceramic materials based on cadmium tellurite developed for stable host phosphor is reported in this paper. The structure of TeO2 and CdO-TeO2 system has been investigated by means of FT-Raman, Infrared (IR) spectroscopy and x-ray diffraction (XRD) spectroscopies. Cadmium tellurite system were prepared with the compositions of xCdO-(1-x)TeO2 with 0.1 x 0.5 in percent molar ratio, doped with 1% mol MnO2, using solid state method. The x-ray diffraction measurement results showed that the phase in the cadmium tellurite system matched quite well with the standard ICDD files, indicating that the phases present in this sample appeared to be a phase of -TeO4 trigional bipyramid (tbp), CdTe2O5 and CdTeO3. The Raman and Infrared spectra show that the structures are mainly builds by TeO4 (tbp) groups,TeO3+1 trigional pyramid (tp) and TeO3 (tp), while Cd2+ ions play as network modifiers. As addition concentration of CdO increases, TeO4 (tbp) groups progressively change polymerized framework structure in TeO4 (tbp) into TeO3+1 trigional pyramid (tp) and TeO3 (tp). On the contrary, the addition of 1 mol % MnO2 into the sample did not giving any effect on the structural of the final samples.
Electrical Properties of Polypyrrole Conducting Polymer at Various Dopant Concentrations
Authors: Othman N. , Talib Z. A. , Kassim A. , Shaari A. H. , Liew J.Y.C.
Published: October 2017

Polypyrrole conducting polymer was prepared by chemical reaction method with various concentrations of iron (III) chloride (FeCl3) as dopant. The dc conductivity was obtained from current-voltage characteristic by using parallel-plate techniques in the temperature range of 100-300K. With the involvement of chloride, Cl- in the polymeric chain, the conductivity increased as temperature and the dopant concentration increased. To describe the electrical transport process, Mott’s 1-D, 2-D and 3-D variable range hopping (VRH) models have been considered. The result gives evidence of transport mechanism based on Mott’s 3-D VRH mechanism for all various dopant concentrations studied.
Vibrational Studies of Calcium Magnesium Ultraphosphate Glasses
Authors: Hussin Rosli , Ahmad Salim Musdalilah , Alias Nur Shahira , Abdullah Mutia Suhaibah , Abdullah Suhailah , Ahmad Fuzi Siti Aishah , Hamdan Sinin , Md Yusuf Mohd Nor
Published: October 2017

Phosphate glasses in a system of magnesium calcium phosphate for host matrix luminescent materials wereinvestigated. The glass samples in a series of xMgO–(40- x)CaO–60P2O5 in molar ratio (0x40 mol%) were preparedusing melt-quenching technique. The effect of Mg and Ca content on the structure and glass stability againstcrystallization in the system of MgO–CaO–P2O5 ultraphosphate has been investigated using XRD, Infrared and Ramanspectroscopy. The compositions containing up to 40 mol% of CaO and /or MgO formed glasses and no crystallinephases were detected by XRD. The results of IR and Raman spectroscopy suggest that the phosphate network of theseglasses is composed of middle (Q2) and branching (Q3) phosphate tetrahedral and other calcium/magnesium anions.All the symmetric and asymmetric stretching vibrations of POP and PO2 observed in the spectra are characteristic ofQ3 and Q2 groups. The glass network, especially the Q2 units can be modified by the presence of Ca and Mg ions. Thismodification is primarily associated with the phosphate and the Q2 and Q3 phosphate units randomly distributed in thenetwork. Spectroscopic results shows that the modification of the phosphate network is higher for the Ca containingglasses with respect to the Mg ones, at the same alkali earth content, due to the well defined Ca properties as amodifying cation. Formation of P–O–H bond expresses the hygroscopic nature of the phosphate glasses. This studyshows that the vibrational spectroscopy (Infrared and Raman) are provide useful, complementary information aboutthe network structures of ultraphosphate glasses.
Temperature Behavior Visualization on Rubber Material Involving Phase Change Simulation
Authors: Darwis Roziha , Alias Norma , Yaacob Nazeeruddin , Othman Mohamed , Abdullah Nurashikin , Yuan Ying Teh
Published: October 2017

Material engineers are excited with the design of a new rubber product through the development of a new composite of the rubber product. Our research contributes in developing the mathematical simulation based on Gauss-Seidel Red-Black and Gauss-Seidel method to solve the temperature behavior of the rubber elasticity, strength, entropy and classical experiments through reference publications and stimulating rubber physics research elsewhere. The temperature behavior leads to the partial differential equation of heat transfer problems involving phase change simulation. The prototype of the algorithm implemented on Linux operating systems using C language.
Dielectric Properties of La0.4Ca0.6Mn0.4Ti0.6O3 Ceramic Oxide
Authors: Primus Walter Charles , Shaari Abdul Halim , Wan Yusoff Wan Mohd. Daud , Talib Zainal Abidin , Mustafa Mazni
Published: October 2017

The dielectric properties of La0.4Ca0.6Mn0.4Ti0.6O3 ceramic oxide was investigated under various temperatures. A Debyelikebehaviour was observed although the dc conduction effects at low frequencies almost overlapping the relaxationpeak in the imaginary part. This feature of dielectric behaviour was explained using trapping mechanism. An equivalentcircuit modeling was proposed to represent the electrical behaviour of this sample using universal capacitor, C*(4) =B(i4)n-1. The circuit modeling is consisting of two series of dispersive capacitors in parallel with conductance and highfrequency capacitance.
Diagonally Implicit Runge-Kutta Fourth Order Four-Stage Method for Linear Ordinary Differential Equations with Minimized Error Norm
Authors: Che Jawias Nur Izzati , Ismail Fudziah , Suleiman Mohamed , Jaafar Azmi
Published: October 2017

We constructed a new fourth order four-stage diagonally implicit Runge-Kutta (DIRK) method which is specially designed for the integrations of linear ordinary differential equations (LODEs). The method is obtained based on theButcher’s error equations. In the derivation, the error norm is minimized so that the free parameters chosen are obtained from the minimized error norm. Row simplifying assumption is also used so that the number of equations forthe method can be reduced and simplified. A set of test problems are used to validate the method and numerical results show that the new method is more efficient in terms of accuracy compared to the existing method.
Mathematical Modeling and Hybrid Heuristic for Unequal Size Facility Layout Problem
Authors: Nordin Nurul Nadia , Zainuddin Zaitul Marlizawati , Salim Sutinah , Ponnusamy Raja Rajeswari
Published: October 2017

The facility layout design has been regarded as the key to improve plant productivity, which are relevant to both manufacturing and service sectors. Facility Layout Problems (FLPs) are known to be NP-hard problems; various optimization approaches for small problems and heuristic approaches for the larger problems have been proposed to elucidate the problem. A mathematical model is developed for the unequal size facility layout problem with fixed flow between departments. We are considering the orientations of the departments with various sizes and aims to minimize the distance traveled by people, material, and other supporting services in the safest and most effective manner. Some of the constraints considered in the modeling are the restricted areas, reserved departmentry locations, and also the irregularity of the shapes of manufacturing layout. This paper focuses on the mathematical model and the solution of the non-quadratic assignment problem (non-QAP) by hybridizing the meta-heuristic methods i.e. Genetic Algorithm (GA) and Simulated Annealing (SA). This work could be used in future as a reference for those researchers interested in tackling this challenging unequal facility layout problem.
Photocatalytic degradation of basic and reactive dyes in both single and binary systems using immobilized TiO2
Authors: Teng Ong Siew , Kheng Lee Chnoong , Zainal Zulkarnain , Sin Keng Pei , Tiong Ha Sie
Published: October 2017

In order to avoid the separation process of fine titanium dioxide (TiO2) photocatalyst at the end of the treatment, a simple and effective method was explored to immobilize TiO2 nanoparticles on a support material. In this paper, the effectiveness of using immobilized TiO2 supported on glass plates to remove Basic Blue 3 (BB3) and Reactive Orange (RO16) from single and binary dye solutions was investigated. The photocatalytic degradation of both dyes was investigated under the illumination of either UV or sunlight. The percentage of dye removal increased with increasing irradiation time and the maximum number of dip coatings that can be applied was ten. For all the dye solutions studied, the percentage of dye removal decreased with increasing number of usage of immobilized TiO2. Due to the ease of usage and good photocatalytic efficiency, the findings showed the potential application in decolouring organic dyes for pollution prevention.
Synthesis, characterization and fungicidal activity of some diorganotin(IV) with 2-thioacetic-5-phenyl-1,3,4-oxadiazole
Authors: Yousif Emad , Adil Hadeel , Majeed Ahmed , Farina Yang
Published: October 2017

Complexes of the type R2SnL2, where R = phenyl, butyl and methyl and LH = 2-thioacetic-5-phenyl-1,3,4-oxadiazole, have been synthesized and characterized by physico-chemical (elemental analysis, and electrolytic conductance) and spectral (UV-Visible, IR and (1H, 13C and 119Sn NMR) techniques. Monomer structures for the complexes, bidentate and octahedral geometry was proposed for the complexes prepared. Preliminary in vitro tests for fungicidal activity show that all prepared compounds display good activity to Gibberela, Cercospora arachidicola, Physolospora piricola and Fusarium oxysporum. Moreover, the Ph2SnL2 shows a higher inhibition percentage then diorganotin carboxylate.
Sample Preparation Methods for Pesticides Analysis in Food Matrices and Environmental Samples by Chromatography-Based Techniques: A Review
Authors: Sobhanzadeh Elham , Abu Bakar Nor Kartini , Abas Mhd Radzi , Nemati Keivan
Published: October 2017

Much attention has been made in pesticide analysis to improve agricultural productivity and control these compounds in food and environmental samples. Different methods have been applied in pesticide analysis, among these; methods based on chromatographic separation with mass spectrometric detection have been extremely useful methods for determination of pesticide residues. Despite employing of powerful instrumental techniques, the risk of interference increases with the complexity of the matrix studied, so sample preparation prior to instrumental analysis is necessary. This article reviews the analytical characteristics of the different sample preparation methods for determination of pesticide residues in food and environmental samples and biological fluids, moreover this study describes advantages, disadvantages and details on the analytical characteristics of the procedure that have been applied recently in different sample preparation methods and their application s in combination with chromatographic mass spectrometric analysis. This article provides selection of a reliable method which will be useful for the quantitative analysis of pesticide residues in variety of samples based on their evaluation in recent applications.
M/M/1 Retrial queueing system with negative arrival under non-preemptive priority service
Authors: Ganapathi Subramanian A. Muthu , Ayyappan G. , Sekar G.
Published: October 2017

Consider a single server retrial queueing system with negative arrival under non-pre-emptive priority service in which three types of customers arrive in a poisson process with arrival rate λ1 for low priority customers and λ2 for high priority customers and λ3 for negative arrival. Low and high priority customers are identified as primary calls. The service times follow an exponential distribution with parameters μ1 and μ2 for low and high priority customers. The retrial and negative arrivals are introduced for low priority customers only. Gelenbe (1991) has introduced a new class of queueing processes in which customers are either positive or negative. Positive means a regular customer who is treated in the usual way by a server. Negative customers have the effect of deleting some customer in the queue. In the simplest version, a negative arrival removes an ordinary positive customer or a random batch of positive customers according to some strategy. It is noted that the existence of a flow of negative arrivals provides a control mechanismto control excessive congestion at the retrial group and also assume that the negative customers only act when the server is busy. Let K be the maximumnumber of waiting spaces for high priority customers in front of the service station. The high priorities customers will be governed by the Non-preemptive priority service. The access from the orbit to the service facility is governed by the classical retrial policy. This model is solved by using Matrix geometric Technique. Numerical study have been done for Analysis of Mean number of low priority customers in the orbit (MNCO), Mean number of high priority customers in the queue(MPQL),Truncation level (OCUT),Probability of server free and Probabilities of server busy with low and high priority customers for various values of λ1 , λ2 , λ3 , μ1 , μ2 ,σ and k in elaborate manner and also various particular cases of this model have been discussed.
A study on preparation and characterization of carbon doped TiO2 nanotubes
Authors: Sreekantan Srimala , Hazan Roshasnorlyza , Lockman Zainovia , Mat Ishak
Published: October 2017

The present study is directed to clarify the influence of carbon doping on the degradation of methyl orange. TiO2 nanotubes were prepared by anodizing titanium foils in a two electrode configuration bath with titanium foil as the anode and platinum as the counter electrode. The electrochemical bathconsists of 1 M Na2SO4 with 0.7 g ammonium fluoride, NH4F. The nanotubes obtained were further doped with carbon via in-situ and ex-situ method. Incorporation of carbon on TiO2 via in-situ method is accomplished during the anodization process by introducing oxalic acid into electrolyte while theex-situ doping involves carbon incorporation into pre-fabricated TiO2 nanotube via flame annealing using carbon blackN330. Characterization such as Scanning Electron Microscope (SEM), Energy Dispersive X-ray Analysis (EDX), and X-Ray Diffraction (XRD) are used to determine the surfacemorphology, composition of dopants, and phases exists. Well ordered nanotube with good adherence and smooth surface was obtained for both methods. When the oxide was annealed, X-ray diffraction analysis revealed the presence of anatase and rutile phase. The photocatalytic properties of thepure TiO2 and carbon doped TiO2 were tested for methyl orange degradation and the result indicated that the in-situ doped TiO2 has much better degradation than the ex-situ and pure TiO2. The percentage of methyl orange degradation for in-situ was 20% and 41% higher than ex-situ doped TiO2 and pure TiO2, respectively.
Synthesis of 4’,5,7-trihydroxyflavanone and 3’,4’,5,7-tetrahydroxyflavanone and antioxidant activity
Authors: Ahmad Farediah , Mohamed Adib Adiana , Idris Muhammad Sum
Published: October 2017

Natural flavonoids, 4’,5,7-trihydroxyflavanone and 3’,4’,5,7-tetrahydroxyflavanone were synthesised via their respective chalcone. The initial step wasto synthesise derivatives of 2-hydroxyacetophenone and benzaldehyde by protecting the phenolic hydroxyl groups. The chalcone was synthesised byClaisen-Schmidt condensation. Acid hydrolysis and subsequent treatment with sodium acetate of 2’-hydroxy-4,4’-6’-tris(methoxymethyloxy)chalconeand 2’-hydroxy-3,4,4’,6’-tetrakis(methoxymethyloxy)chalcone, gave 4’,5,7-trihydroxyflavanone and 3’,4’,5,7-tetrahydroxyflavanone, respectively.3’,4’,5,7-Tetrahydroxyflavanone was found to be more potent as an antioxidant agent than 4’,5,7-trihydroxyflavanone with 83.11% inhibition and SC508.57 μg/mL in the radical scavenging activity by ESR method.
Application of Response Surface Methodology (RSM) for optimizing removal of Cr(VI) wastewater using Cr(VI)-reducing biofilm systems
Authors: Mohammed Nurfadilah , Ahmad Wan Azlina
Published: October 2017

Response surface methodology (RSM) involving central composite design (CCD) was employed to obtain optimal conditions for Cr(VI) wastewater treatment by Cr (VI) reducing biofilm systems. On the basis of a CCD, RSM was used to determine the effect of initialmetal concentrations (40-100 mgL-1), nutrient supplementations (10-20%) and flowrate (3-6 mLmin-1) on the levels of response, i.e. Cr(VI) reduction efficiency. A set of 20 experimental runs were needed for optimizing of the operating conditions. Quadratic regressionmodels with estimated coefficients were developed to describe the Cr (VI) reduction. Analysis of variance (ANOVA) showed a highcoefficient of determination (R2) value of 0.9941, thus ensuring a satisfactory adjustment of the second-order regression model with theexperimental data. Cr (VI) reduction had significant effect on all the three dependent variables. The experimental results show that Cr(VI)-reducing biofilm systems could effectively reduce Cr (VI), 100% at the optimum conditions of initial metal concentration of 100mgL-1, nutrient supplementation of 20% and flowrate of 3 mLmin-1. The experimental observations were in reasonable agreement withthe modelled values.
A comparison of multivariate control charts for skewed distributions using weighted standard deviations
Authors: B.C. Khoo Michael , Yin Teh Sin , Yin Eng May
Published: October 2017

The quality of a manufacturing process usually depends on more than one quality characteristic. Thus, most process monitoring data are multivariate in nature. The assumption that the underlying process follows a multivariate normal distribution is usually required by most multivariate quality control charts. However, in most process monitoring situations, the multivariate normality assumption is often violated. Multivariate control charts for skewed distributions have been suggested to enable process monitoring to be made when the underlying process distribution is skewed. Among the recent heuristic multivariate charts for skewed distributions suggested in the literature are those based on the weighted standard deviation (WSD) approach. This paper compares the performances of three multivariate charts for skewed distributions incorporating the WSD method, namely, the WSD T 2 , WSD multivariate cumulative sum (WSD MCUSUM) and WSD multivariate exponentially weighted moving average (WSD MEWMA) charts. These heuristic charts are compared based on the multivariate lognormal, gamma and Weibull distributions. The charts’ performances are evaluated using the false alarm rates, computed via a Monte-carlo simulation. The chart with the lowest false alarm rate for most of the skewness levels and sample sizes will be identified as the chart having the best performance.
Molecularly imprinted polymers for solid phase extraction of orghanophosphorus pesticides
Authors: Sanagi Mohd Marsin , Salleh Syairah , Wan Ibrahim Wan Aini , Abu Naim Ahmedy
Published: October 2017

Molecularly imprinted polymer-solid phase extraction (MIP-SPE) adsorbent was prepared for the analysis of selected organophosphorus pesticides(OPPs) in environmental sample. In this work, the influence of process parameters on the preparation of imprinted polymer is presented. In theprocedure of polymerization, molecularly imprinted bulk polymer was prepared using quinalphos and methacrylic acid (MAA) as template molecule and functional monomer, respectively. The influence of the following parameters on recognition properties was investigated namely, types of crosslinker (ethylene glycol dimethacrylate (EGDMA) or divinylbenzene (DVB)) and porogenic solvents (acetonitrile, dichloromethane, toluene, chloroform). Molar ratio of template:functional monomer:cross linker was fixed at 1:4:20. Soxhlet extraction method was conducted to remove the imprint molecule in order to create the recognition sites. A blank/non-imprinted polymer (NIP) was produced simultaneously using identical procedure except in the absence of template molecule.
Optimization of lipase-catalyzed synthesis of flavour esters in solvent free system
Authors: Muhamad Syamsul Kamar , Mat Radzi Salina , Othman Siti Salhah , Abdul Rahman Mohd Basyaruddin , Mohd Noor Hanina
Published: October 2017

The effects of important reaction parameters for enhancing flavour esters formation through lipase-catalyzed reaction were investigated in this study.Various commercial immobilized lipases were used to catalyze the esterification reaction between short-chain fatty acids and alcohols to produce flavour esters which are nonyl caprylate and ethyl valerate which differ in chain length of esters. These synthetic flavour esters with fruity notes are widely used in food, cosmetic and pharmaceutical industries. The effect of various reaction parameters was optimized to obtain a high yield of flavour esters. A maximum percentage for nonyl caprylate with conversion of flavour esters more than 90 % in a solvent-free system was successfully obtained under the following conditions: reaction time (RT), 5 hours; reaction temperature, 40 °C; amount of immobilized lipase, 25 % w/w of total substrate and shaking speed 200 rpm. Compared to ethyl valerate, a maximum percentage conversion of flavour ester more than 80 % in solvent free system was successfully obtained under following conditions: reaction time (RT), 45 minutes; reaction temperature, 40 °C; amount of immobilized lipase, 15 % w/w of total substrate and shaking speed 200 rpm. Comparison between these two ester showed that the chain length give an effect to optimize the reaction condition in esterification reaction.
Sylvester-type matrices for sparse resultants
Authors: Ahmad Shamsatun Nahar , Aris Nor’aini
Published: October 2017

The resultant matrix of a polynomial system depends on the geometry of its input Newton polytopes. Therefore for sparse inputs, the matrix is lower in dimension. The aim of the study is to infer conditions on the class of polynomial systems that can give a resultant matrix whose size is minimized, that is an optimal or Sylvester-type sparse resultant matrix. From the work of Emiris, the ‘incremental algorithm’ has been claimed to produce optimal matrices for the class of multi-homogeneous (or multigraded) systems of special structure. Cyclic polynomial systems for n-root problems also fall under this classification. We have applied the Maple multires package to obtain Sylvester-type matrices for some examples. The ultimate aim of the study is to verify whether the multigraded systems constitute to the only class of polynomial systems that can give sparse resultant optimal matrix; hence giving a necessary and sufficient condition for producing exact sparse resultants.
Cracking the genetic code of human virus by using open source bioinformatics tools
Authors: Friend Tambunan Usman Sumo , Parikesit Arli Aditya
Published: October 2017

Viral infection is a very serious threat to humanity. It causes malicious diseases, such as HIV/AIDS, dengue, and Avian Influenza, therefore, novel method in virology to combat the viral infection is necessary. Bioinformatics provides outstanding tools for developing vaccines, PCR primers, mutation detection and drugs based design on genetic engineering principles. Those tools are mostly freeware. Algorithm from the computer science has made major contribution to them. Bioinformatics experiment greatly reduces the cost and time in wet laboratory experiment. Our labs has successfully designed PCR primers, vaccine, and mutations prediction. The vaccine design is elaborated for Dengue and HPV. The design has BLAST homology of more than 90%, and RSMD value of 0.1. Those data shown, that the design have identical structure with the native viral protein. However, their efficacy should be verified in the wet laboratory experiment. The future of medicine will greatly be shaped by advancement in bioinformatics.
Role of oxidant in surface modification of carbon nanotubes for tyrosinase immobilization
Authors: Abdul Majid Zaiton , Mohammad Sabri Nur Anis , Buang Nor Aziah , Shahir Shafinaz
Published: October 2017

Studies on the development of interface between biological molecules and novel nanomaterials have attracted research worldwide. Carbon nanotubes(CNTs) have become an important matrix for the fabrication of biomaterials due to its unique properties. Surface properties of the CNTs and the medium of immobilization are critical in the immobilization of biological molecules such as enzymes. In this study surface modification of multi-walled carbon nanotubes (MWCNTs) for carboxylic moieties attachment was accomplished by acid treatment and reaction with potassium permanganate. The effect of these two oxidants on the surface modification of MWCNTs for the purpose Tyrosinase immobilization was studied. Commercial MWCNTs were treated with either concentrated sulfuric acid and nitric acid mixture with ratio 3:1 or with 0.1 M potassium permanganate via reflux, stirring and ultrasonication. The resulting surface modified MWCNTs were characterized with FT-IR spectrophotometer, FESEM, and TGA analyzer. The immobilized Tyrosinase was tested for leaching assay. The FTIR spectra of functionalized MWCNTs showed a significant peak in the range of 1700 cm- 1 to 1729 cm-1 indicating the presence of carboxyl double bond, which confirmed the successful functionalization of MWCNTs by chemical oxidation. The carboxylic peak of MWCNTs treated with KMnO4- showed higher intensity as compared to acid-treated MWCNTs. The acid-treated MWCNTs displayed a sparkling crystalline-like particles while the KMnO4-modified MWCNTs consists of smooth powdery particles. Both treated MWCNTs also showed good dispersion in aqueous solution with different amount of acidic and basic site present.
Synthesis of basic zeolite from coal fly ash and its reactivity in Knoevenagel reaction
Authors: Ramli Zainab , Ahmad Rusmili Siti Haslina
Published: October 2017

Zeolite was hydrothermally synthesized from coal fly ash in NaOH solution and static condition, at various times of crystallization and treatment. Geltreated with ultrasonication before heating resulted in the formation of pure zeolite P (Na-P) while untreated gel formed a mixture of sodalite and Na-P. Pure zeolite P was produced in 5 days and stable up to 31 days of crystallization time without the trace of sodalite formed. The synthesized Na-P was then ion-exchanged with potassium (K-P) and cesium (Cs-P) ions in order to increase the basicity of the Na-P obtained. The reactivity of the catalysts was tested in Knoevenagel reaction between benzaldehyde and malononitrile, producing solid benzylidenemalononitrile as single product. The reactivity was measured by the time when the first solid product formed. K-P catalyst was found to be the most reactive followed by Cs-P and Na-P in which the reactivity depends more on the number of base sites as well as the basic strength of zeolite. In conclusion, zeolites synthesized from CFA is potential catalysts for the Knoevenagel reaction.
P-SV wave diffusion in fluid-saturated medium
Authors: Ling C.C. Dennis , A.A. Zainal
Published: October 2017

Propagating P-SV waves in the fluid-saturated mediums are categorized to fall into two distinct groups: insoluble and soluble mediums. These waves are known as surface Rayleigh waves. By introducing these waves with slowness in accordance to Snell Law, the diffusive and rotating waves are obtained. The results bear out that the propagating P-SV waves in soluble medium share similar diffusion characteristic as of insoluble medium while the discussions on fluid density in the mediums show that high density fluid promotes diffusive characteristic while low density fluid endorses nondiffusive P-SV waves. There is a compressed zone during the propagation of P-SV waves in medium saturated with high density fluids.
Robust start up stage for beltline moulding process variability monitoring using vector variance
Authors: Mohd Salleh Rohayu , A. Djauhari Maman
Published: October 2017

One of the primary problems encountered in monitoring the variability of beltline moulding process in an automotive industry is the estimation of parameters in the start-up stage. This problem becomes more interesting because the process is in multivariate setting and must be monitored based on individual observations, i.e., the sample size of each subgroup is 1. This paper deals with a robust estimation of location and scale during the start-up stage. For this purpose, we use Mahalanobis distance in data ordering process. But, in data concentration process, we use vector variance (VV). This method is highly robust and computationally efficient. Its advantage in monitoring the variability of beltline moulding process will be compared with the non-robust method.
Chemical constituents and antiviral study of Goniothalamus velutinus
Authors: Ahmad Fasihuddin Badruddin , Mohd Sallehuddin Nur Khairun Nisa , Assim Zaini
Published: October 2017

Phytochemical study on the stem barks of Goniothalamus velutinus resulted in the isolation of three compounds identified as goniothalamin (1), pinocembrine (2) and naringenin (3). Their structures were elucidated using various spectroscopic methods especially Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) and gas chromatography-mass spectrometry (GC-MS). Goniothalamin (1) has been isolated from several Goniothalamus spp. but no report on the isolation of (1) from Goniothalamus velutinus. Antiviral properties of (1) against Measles virus showed weak activity compared to positive control, ribavirin.
Quantitative structure-activity relationship for antimalarial activity of artemisinin
Authors: Jamaludin Rosmahaida , Hasan Mohamed Noor
Published: October 2017

The increase in resistance to older drugs and the emergence of new types of infection have created an urgent need for discovery and development of new compounds with antimalarial activity. Quantitative-Structure Activity Relationship (QSAR) methodology has been performed to develop models that correlate antimalarial activity of artemisinin analogs and their molecular structures. In this study, the data set consisted of 197 compounds with their activities expressed as log RA (relative activity). These compounds were randomly divided into training set (n=157) and test set (n=40). The initial stage of the study was the generation of a series of descriptors from three-dimensional representations of the compounds in the data set. Several types of descriptors which include topological, connectivity indices, geometrical, physical properties and charge descriptors have been generated. The number of descriptors was then reduced to a set of relevant descriptors by performing a systematic variable selection procedure which includes zero test, pairwisecorrelation analysis and genetic algorithm (GA). Several models were developed using different combinations of modelling techniques such as multiple linear regression (MLR) and partial least square (PLS) regression. Statistical significance of the final model was characterized by correlation coefficient, r2 and root-mean-square error calibration, RMSEC. The results obtained were comparable to those from previous study on the same data set with r2 values greater than 0.8. Both internal and external validations were carried out to verify that the models have good stability, robustness and predictive ability. The cross-validated regression coefficient (r2cv) and prediction regression coefficient (r2 test) for the external test set were consistently greater than 0.7. The QSAR models developed in this study should facilitate the search for new compounds with antimalarial activity.
Home-made vacuum system for calculating the apparent density of solid materials
Authors: Rozali Annuar Nur Hazirah , Ahmad Fadzlillah Nurrulhidayah , Karim Ainul Hakimah , Ruslan Nurun Najwa , Timmiati Sharifah Najiha , Abdul Jalil Aishah , Triwahyono Sugeng
Published: October 2017

Home-made vacuum system was set up for measuring the apparent density of solid materials or more accurately the volume of solid materials. The volume of samples was calculated based on the method of gas displacement and the inversely proportional relationship between the absolute pressure and volume of a gas known as Boyle's Law, pV=k. Nitrogen gas was used as a probe and the measurement was done at room temperature and at low pressure in order to minimize the effect of the compressibility factor of the gas. The system was calibrated by stainless steel ball with the error was less than 5%. The apparent density of hollow stainless steel (non-porous), rice (irregularly shaped) and Clorets sweet (regularly shaped) were 7.61, 1.60 and 1.23 g/mL, respectively. Whereas the apparent density of porous powdered materials were 1.34, 1.26 and 1.67 g/mL for Pt/SO4 2--Al2O3, WO3-ZrO2 and Portland Cement, respectively. The experimental error for measuring the solid volume was less than 5%.
Chemical Oxygen Demand reduction in industrial wastewater using locally isolated bacteria
Authors: Musa Nor Syamimi , Ahmad Wan Azlina
Published: October 2017

Wastewater that has been discharged from the pineapple industry contributes to high levels of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Suspended Solids (SS). The high levels of COD concentrations in wastewater are toxic to biological life and will affect aquatic environment. Currently, there are many methods that have been developed to treat pineapple industry wastewater such as ozonation, reverse osmosis and filtration. However, these conventional methods are costly and generate large amounts of sludge. Biological treatment may be a good alternative since its operational cost is less and it creates an environmental friendly atmosphere compared to the conventional methods. In this study, the effectiveness of COD reduction involving a single bacterial culture D, G and I isolated from a pineapple industry wastewater were used in batch system. The COD reduction of pineapple industry wastewater was carried out using bacterial culture and pellet. The performance of these systems in reducing the COD level was monitored within 3 days. The COD reduction was analyzed using a Hach DR/4000 U spectrophotometer. The bacterial pellet D, G and I showed a maximal COD reduction of 87%, 77% and 94% respectively after 3 days exposure to wastewater. The wastewater treatment using bacterial pellet showed higher COD reduction as compared to treatment using whole bacterial culture. FESEM analysis showed that bacteria D, G and I appeared as rod shaped.
Radiation induced emulsion grafting of glycidyl methacrylate onto high density polyethylene: A kinetic study
Authors: Nasef Mohamed Mahmoud , Sugiarmawan Indriani Andromeda
Published: October 2017

Emulsion graft polymerisation of glycidyl methacrylate monomer onto high density polyethylene (HDPE) resin was studied. The radicals required to initiate the reaction were produced in HDPE resin by irradiation with the electron beam accelerator at ambient and vacuum conditions. The grafting reaction of GMA with irradiated HDPE was initiated by emulsion method using Tween 20 as a surfactant and water as a solvent under controlled conditions. The kinetic behavior of grafting reaction was investigated with respect to the degree of grafting under various parameters i.e. monomer concentration, radiation dose, grafting temperature and surfactant concentration. The degree of grafting was found to be a function of the investigated parameters. Particularly, surfactant concentration in the emulsion was found to be crucial for determining the micelle size and eventually the degree of grafting. The order of dependence of the initial rate of grafting on the monomer concentration and the irradiation dose was found to be 0.94 and 0.60, respectively. The initial rate of grafting was also found to increase with the increase in the grafting temperature varied in the range of 308-333 K. The optimum reaction parameters required to obtain desired and reproducible degrees of grafting in the resin could be identified. Moreover, the emulsion radiation grafting method was found to offer essential advantages over the conventional grafting with solvents including low radiation dose, less monomer concentration and cost effectiveness.
Grammars controlled by petri nets with inhibitor arcs
Authors: Turaev Sherzod , Selamat Mohd Hasan
Published: October 2017

A Petri net controlled grammar is a grammar equipped with a Petri net whose transitions are labeled with production rules of the grammar, and the associated language consists of all terminal strings which can be derived in the grammar and the sequence of rules in every terminal derivation corresponds to some occurrence sequence of transitions of the Petri net which is enabled at the initial marking and finished at a final marking of the net. In this paper we define grammars controlled by Petri nets with inhibitor arcs and investigate their computational capacities.
Solving second kind linear Fredholm integral equations via Quarter-Sweep SOR iterative method
Authors: Muthuvalu Mohana Sundaram , Sulaiman Jumat
Published: October 2017

In this paper, we consider the numerical solutions of linear Fredholm integral equations of the second kind. The Quarter-Sweep Successive Over-Relaxation (QSSOR) iterative method is applied to solve linear systems generated from discretization of the second kind linear Fredholm integral equations using quadrature method. In addition, the formulation and implementation of the proposed method to solve the problem are also presented. Numerical tests and comparisons with other existing methods are given to illustrate the effectiveness of the proposed method.
Annealing effect on the microstructural and magnetic properties of Er2.5Y0.5Fe5O12 films prepared by sol-gel method
Authors: E. Shaiboub Ramadan , Ibrahim Noor , Abdullah Mustafa , W. Abdulhade Ftema
Published: October 2017

The effect of annealing on the microstructural and magnetic properties of Er2.5Y0.5Fe5O12 sol-gel films were studied at different temperatures using X-ray diffraction (XRD), field emission scanning electron microscopic (FESEM) and vibration sample magnetometer (VSM).The results show that the XRD pattern of the samples have a single phase garnet structure with reduction in the lattice parameter of Er:YIG films due to the smaller ionic radii of Er3+ compare to Y3+. The sizes of the particles are in the range of 50 to 90 nm. The saturation magnetization (Ms) increase and then decreases as the temperature increased.
Monitoring the variability of beltline moulding process using Wilks’s statistic
Authors: Mohd Noor Aishah , A. Djauhari Maman
Published: October 2017

Due to the increase of the complexity of customer demand on products and services, monitoring process quality is becoming multivariate in nature. In this setting there are two important parameters to be monitored, i.e., the mean vector and the covariance structure which determines the variability of the process. This paper deals with process variability monitoring of beltline moulding process at an automotive industry where the process is in multivariate setting and monitoring process is based on individual observations. Our approach is based on Wilks’s statistic. A real application will be presented and the strength of that statistic, as well as its limitations, will be discussed.
A feedback queue with additional optional batch service
Authors: Kalayanaraman R. , Sumathy S.
Published: October 2017

A single server infinite capacity queuing system with Poisson arrival process along with Bernoulli feedback decision process is considered wherein the server provides two types of service. The first essential service is rendered one by one to all the customers and second optional service is given in batches of fixed size b. For this model the steady state probability generating function for the queue length process has been obtained and average queue length has been found explicitly. Results for particular cases are obtained and some numerical results are presented to test the feasibility of the queuing model.
Determination of Lewis and Brönsted acid sites by gas flow-injection technique
Authors: Musthofa Malik , Karim Ainul Hakimah , Ahmad Fadzlillaah Nurrulhidayah , Rozali Annuar Nur Hazirah , Abdul Jalil Aishah , Triwahyono Sugeng
Published: October 2017

Gas flow-injection technique pyridine-FTIR was studied for determination of Lewis and Brönsted acid sites on the solid super acid catalysts. The system consists of stainless steel gas cell which can be heated up to 623 K, CaF2 windows, pyridine injection port and double liquid nitrogen trap for removal of moisture. Pure nitrogen gas and pyridine were used as a carrier and probe molecule. Pyridine was injected to the sysem at 423 K followed by flushing of N2 gas through double liquid nitrogen trap at 423 for 1 h and at 573 K for 30 min. All spectra were recorded at room temperature. This technique gave similar results to those of taken by vacuum system for HZSM-5, Pt/SO4 2--ZrO2, Al2O3 catalysts.
Morphological evolution of ternary InxGa1-xAs nanowires (NWs) grown with Au particle-assisted using vertical chamber MOCVD
Authors: Wibowo Edy , Othaman Zulkafli , Sakrani Samsudi , S. Ameruddin Amira , Aryanto Didik , Muhammad Rosnita , Sumpono Imam
Published: October 2017

The morphology and chemical composition of InxGa1-xAs NWs grown on undoped GaAs (111)B substrate have been investigated using scanning electron microscopy (SEM) and energy dispersive x-ray (EDX), respectively. SEM images show that InxGa1-xAs NWs underwent morphological evolution as temperature changes. By changing the growth temperature, the growth mechanism of NWs was assumed to have changed. Both characterizations results suggested the growth mechanism has strong influence to the evolution of the NWs morphologies and also to the distribution of the chemical composition of NWs.
Studies of the self-assembled growth mechanism on nanocrystalline silicon nanodots
Authors: Sakrani Samsudi , Sumpono Imam , Tarjudin Nurul Aini , Othaman Zulkafli
Published: October 2017

Nanocrystalline silicon (nc-Si) nanodots have been grown on corning glass (7059) substrate using a self-assembly VHF-PECVD method under the following experimental conditions: Fixed deposition temperatures of 300/400 °C, deposition times 30/60 s, plasma power of 10 W, silane gas flow rate of 10 sccm, as well as deposition pressure of 10-2 torr. It is predicted that the onset of nucleation began immediately after the deposition and start to appear clearly after 20-60 s during which growth mechanisms occur. Essentially, the nanodots were formed onto the substrate in dome-like shapes by virtue of equilibrium surface energies, γLS, γLN andγNS. The associated liquid/solid nucleation mechanism was then simulated and related parameters were obtained: Free energy change per unit volume ΔGv ∼-104 Jmol-1; Surface energies per unit area, γLN = 1.44 Jm-2, γNS = 19 - 60 Jm-2 and γLS = 0.74 Jm-2; Critical energies ΔG* ∼10-15 J; Critical radii r* = 16 - 48 nm. These results were experimentally verified, in particular for selected critical radius r* less than 50 nm.Other measurements were also carried out: PL analysis gave bandgap energies ∼ 1.8-2.4 eV, whilst Raman spectra revealed the coexistence of nc-Si and amorphous Si. It is strongly suggested that, the nc-Si nanodot grown on glass substrate fulfills the Volmer-Weber growth mode with a minor modification.
Some relations on different types of splicing systems
Authors: Yusof Yuhani , Sarmin Nor Haniza , Wan Heng Fong , Karimi Fariba
Published: October 2017

Splicing system is a formal characterization of the generative capacity of specified enzymatic activities acting on initial DNA molecules that was first initiated by Head in 1987. This splicing system is formally illustrated under the framework of Formal Language Theory which is a branch of Theoretical Computer Science and Applied Discrete Mathematics. There are many types of splicing systems including null-context, simple, semi-simple and seminull. In this paper, some relations for those types of splicing systems are presented.
Offline handwritten signature verification using Alpha Cut of Triangular Fuzzy Number (TFN)
Authors: Zakaria Rozaimi , Wahab Abd. Fatah , Md. Ali Jamaludin
Published: October 2017

A new approach in verification of offline handwriting signature had been proposed. This approach use alpha-cut of triangular fuzzy number in verification of the signature where the value of alpha-cut will reduce the interval of confidence fuzzy interval. The best value of alpha-cut will make the confidence fuzzy interval in the smallest interval which the best confidence fuzzy interval consists less number of signature from the present number of the signature. Then, defuzzification method is used to achieve defuzzification signature. The signatures modeled by piecewise fuzzy interpolation rational cubic Bezier curve.
Approximate solutionn of a nonllinear system of integral equations using modified Newton-Kantorovich method
Authors: Eshkuvatov Z.K. , Akhmedov A. , Nik Long N.M.A. , Shafiq O.
Published: October 2017

Modified Newton-Kantorovich method is developed to obtain an approximate solution for a system of nonlinear integral equations. The system of nonlinear integral equations is reduced to find the roots of nonlinear integral operator. This nonlinear integral operator is solved by the modified Newton-Kantorovich method with initial conditions and this procedure is continued by iteration method to find the unknown functions. The existence and uniqueness of the solutions of the system are also proven.