bluuebunny/crossref_metadata_2025 huggingface dataset:
Slant tube characterization for the implementation of k0 - standardization in Nigerian reseach reactor-1
Authors: Abubakar Umar Aliyu , Sunday Jonah A , Sadiq Umar , Hamzah Khaidzir
Published: October 2017

The result for large sample irradiation are continuously piping into the Center for Energy Research and Training (CERT), Ahmadu Bello University, Zaria. Therefore, characterization of the irradiation channels that can accommodate large samples become a challenge. In the first series of trial for large samples irradiation through slant tube of NIRR-1 which is a miniature research reactor is necessary in order to compare with some standard values reported by the arena of researchers including nuclear regulatory bodies. The thermal to epithermal flux ratio (f), epithermal neutron flux distribution parameters (α) were determined using two slant tube channels of NIRR-1. The adopted methodology here is bared and cadmium covered monitor foils method. The vertical dipstick higher purity germanium detector (HPGE) was calibrated and used for the calculation. The f and α values were calculated as 111.8 and -0.04977 respectively.  The good agreement between the certified and experimental values of the shaping factors was achieved.
On the generalized conjugacy class graph of some dihedral groups
Authors: Zaid Nurhidayah , Sarmin Nor Haniza , Rahmat Hamisan
Published: October 2017

A graph is a mathematical structure which consists of vertices and edges that is used to model relations between object. In this research, the generalized conjugacy class graph is constructed for some dihedral groups to show the relation between orbits and their cardinalities. In order to construct the graph, the probability that an element of the dihedral groups fixes a set must first be obtained. The set under this study is the set of all pairs of commuting elements in the form of (a,b) where a and b are elements of the dihedral groups and the lowest common multiple of the order of the elements is two. The orbits of the set are then computed using conjugation action. Based on the results obtained, the generalized conjugacy class graph is constructed and some graph properties are also found.
On the conjugate graphs of finite p-groups
Authors: Zulkarnain Athirah , Sarmin Nor Haniza , Mohd Noor Alia Husna
Published: October 2017

Graphs can be related to groups by looking at its vertices and edges. The vertices are comprised of the elements or sets from the groups and the edges are the properties and conditions for the graph. Recently, research on graphs of groups have attracted many authors. A conjugate graph of a group is defined as; its vertex set is the set of non-central classes of G, and two distinct vertices A and B are connected by an edge if and only if they are conjugate. In this research, the conjugacy class of some finite p-groups are first found. Then, the conjugate graph are determined.
Mini-review: Recent updates on the mathematical modelling of radiation-induced bystander effects
Authors: Nasir Muhamad Hanis , Siam Fuaada Mohd
Published: October 2017

Radiotherapy treatment uses ionizing radiation (IR) in order to kill cancer cells. However, the IR exerted its effects outside the radiation field and causes cell death in healthy cells. This effect namely as radiation-induced bystander effects (RIBE) phenomenon. The scope of the overview of the RIBE phenomenon discussed in this paper includes the RIBE mechanism, danger signaling process, deoxyribonucleic acid (DNA) double-strand breaks (DSBs) damage and the damage repair. This paper extended with the discussion of several mathematical models used to describe the RIBE phenomenon. The discussions towards the mathematical models include the models of signals concentration, the models of bystander effects and the survival fraction model. Mathematical modelling and computer simulation are powerful tools used to understand the biological phenomenon of RIBE. The suitable mathematical model of repair and mis-repair DNA DSBs damage has been briefly reviewed in view of the relevance of this model towards RIBE phenomenon. The outcome of this paper suggested a recommendation for future research on the suitable mathematical model and simulation analysis in describing the complexity of RIBE phenomenon.
Modelling of macrophage interactions by partial differential equations
Authors: Admon Mohd Rashid , Maan Normah
Published: October 2017

The recruitment of macrophages at the tumor sites is the earliest immune response takes place during tumor progression. In breast cancer, experimental studies reveals that the tumor cells are capable of taking advantage on the plasticity of macrophages. Tumor cells respond to epidermal growth factor, EGF that released by macrophages while macrophages respond to colony stimulating factor 1, CSF-1 that released by tumor cells. This chains continues and results a paracrine signalling loop. Consequently, tumor cells and macrophages will aggregate and invade to other tissues or organ. Tumor cells also receive their own signals, adding a new feature of interaction called autocrine signalling loop. By considering in vitro interactions, a system of partial differential equations that incorporate the saturating functions for secretion terms was developed. This functions describes the production of chemical signals saturates with increasing cell density. Stability analysis are then performed to investigate the conditions for aggregation. For a given average of cells density, the homogeneous steady state is non-trivial and the concentration of CSF-1 and EGF are produced in the saturated production. Stability results show that regions for instability are reduced, compared to previous model which assumes the production rates are linear with increasing cell density. Besides, the inclusion of autocrine signalling loop increase the occurrence of aggregation. Decreasing the production rates and chemotaxis sensitivity, together with increasing the decay rates are required to impede the aggregation from initiated. This results should provide valuable clinical suggestions in guiding medical experts during drug designs.
Autocovariance and autocorrelation structures of the generalised autoregressive moving average (GARMA(1,3;δ,1)) model
Authors: Ellappan Suguneswary , Awang Norhashidah , Ramiah Pillai Thulasyammal
Published: October 2017

Generalized ARMA (GARMA) model is a new class of model that has been introduced to reveal some unknown features of certain time series data. The objective of this paper is to derive the autocovariance and autocorrelation structure of GARMA(1,3;δ,1)  model in order to study the behaviour of the model. It is shown that the results of this model can be reduced to the autocovariance and autocorrelation of the standard ARMA model as well as a special case. Numerical examples are used to illustrate the behaviour of the autocovariance and autocorrelation at different δ values to show the various structures that the model can represent
Effects of surfactants on antibacterial drugs – A brief review
Authors: Mohd Hamzah Mohd Amir Asyraf , Aruldass Claira Arul , Ahmad Wan Azlina , Setu Siti Aminah
Published: October 2017

More than half of the reported new discovered/invented drugs are ones with poor solubility, absorption or both. These are the crucial issues that can affect the bioavailability of the drugs. Therefore, improving solubility of poor-soluble drugs is absolutely important. One of the methods to solubilize them in biological fluids is using surfactants. Surfactants are an amphiphilic organic compound containing hydrophilic and lipophilic parts that allow it to reduce the surface tension between two opposite polar phases.  Several popular methods used to determine critical micelle concentration which includes surface tension, conductivity and UV-vis spectroscopy. These surfactants plays number of roles in antibacterial compound synthesis include size reduction agent, stabilizer, solubilizer and drug-carrier. This review will also critically discuss on the roles of surfactants in antibacterial compound synthesis/production and its effect on the antibacterial activity of the drugs.
On the dominating number, independent number and the regularity of the relative co-prime graph of a group
Authors: Abd Rhani Norarida , Mohd Ali Nor Muhainiah , Sarmin Nor Haniza , Erfanian Ahmad
Published: October 2017

Let H be a subgroup of a finite group G. The co-prime graph of a group is defined as a graph whose vertices are elements of G and two distinct vertices are adjacent if and only if the greatest common divisor of order of x and y is equal to one. This concept has been extended to the relative co-prime graph of a group with respect to a subgroup H, which is defined as a graph whose vertices are elements of G and two distinct vertices x and y are joined by an edge if and only if their orders are co-prime and any of x or y is in H.  Some properties of graph such as the dominating number, degree of a dominating set of order one and independent number are obtained. Lastly, the regularity of the relative co-prime graph of a group is found.
Analysis and comparison of numerical algorithms for finding the GCD of certain types of polynomials in the Chebyshev basis
Authors: Isa Siti Nor Asiah , Aris Nor'aini , Mohd Taha Ahmad Zharif Salami
Published: October 2017

This research investigates on the numerical methods for computing the greatest common divisors (GCD) of two polynomials in the orthogonal basis without having to convert to the power series form. Previous implementations were conducted using the Gauss Elimination with partial pivoting (GEPP) and QR Householder algorithms, respectively. This work proceeds to seek for a better approximate solution by comparing the results of the implementations with the QR with column pivoting (QRCP) algorithm. The results reveal that QRCP is as competent as the GEPP algorithm, up to a certain degree, giving a reasonably good approximate solution. It is also found that normalizing the columns of the associated coefficient matrix slightly reduces the condition number of the matrix but has no significant effect on the GCD solutions when applying the GEPP and QR Householder algorithms. However equilibration of the columns by computing its ∞-norm is capable to improve the solution when QRCP is applied. Comparing the three algorithms on some test problems, QR Householder outperforms the rest and is able to give a good approximate solution in the worst case condition when the smallest element of the matrix is 1, the entries ranging up to 15 digits integers.
Heat and mass transfer of steady magnetohydrodynamics mixed convection of dusty fluid flow with chemical reaction past an exponentially stretching sheet
Authors: Izani Siti Nur Haseela , Ali Anati
Published: October 2017

An analysis has been carried out to study a problem of the chemical reaction effects on magnetohydrodynamics (MHD) mixed convective boundary layer flow with a fluid-particle suspension due to an exponentially stretching sheet. The effects of magnetic field and mass transfer are taken into account for the first time in the dusty fluid over the exponentially stretching sheet. The governing partial nonlinear differential equations corresponding to the momentum, energy and concentration are converted into a system of ordinary differential equations by using similarity transformations. The relevant dimensionless equations are then solved numerically using Runge-Kutta-Fehlberg fourth fifth order method (RKF45) with the help of Maple symbolic software. The influence of physical parameters on the velocity, temperature and concentration distributions for both phases were discussed numerically and presented in details through plotted graphs and tables. Also, the numerical values of skin friction coefficient, Nusselt and Sherwood number of the governing parameters are analyzed and discussed in details. The outcomes show that the reaction parameter affects the fluid flow whereas the magnetic field retards the fluid flow. A comparative study of the present results with the previous study provides an excellent agreement.
Role of Na+ ion removal on the photocatalytic properties of hydrothermally-prepared nanotubes TiO2
Authors: Eleburuike Naimat Abimbola , Abu Bakar Wan Azelee Wan , Ali Rusmidah
Published: October 2017

Nanostructured TiO2 enjoys wide patronage for the remediation of water sources that have been contaminated with organic pollutants due to its excellent photocatalytic properties. This study investigated the role of removal of Na+ ions from hydrothermally-prepared TiO2 nanotubes (TNTs) by washing with dilute hydrochloric acid. The photocatalytic activity of TNTs was tested on the degradation of modelled paraquat dichloride-contaminated water. It was found that the amount of residual Na+ ions after acid washing greatly influenced the photocatalytic properties of TNTs. The Na+ ions had significant effect on the crystal structure of TNTs and the crystal structure varied with the annealing temperature. Hence, the effect of the residual Na+ ions was observed at different annealing temperatures of 500, 700 and 800 °C. It was discovered that TNTs containing negligible Na+ ions demonstrated high photocatalytic activity at 500 °C annealing temperature because it consisted of active crystalline anatase species at this temperature. On the other hand, TNTs with high Na+ ion content showed poor performance at 500 °C due to the presence of amorphous sodium titanate species which could result in rapid electron-hole pair recombination. So, it showed highest photocatalytic activity at 800 °C when the crystallinity had increased. Generally, it can be concluded that TNTs with negligible Na+ ion content demonstrated excellent photocatalytic activity by achieving 77.1% degradation of paraquat dichloride compared to those with high Na+ ion content which achieved 61.1% degradation of paraquat dichloride within 5 h.
Pyrolysis of torrefied oil palm wastes for better biochar
Authors: Aliyu Aminu Safana , Abdullahi Nurhayati , Sulaiman Fauziah
Published: October 2017

The objective of this research work is to investigate the effect of torrefaction on the pyrolysis product. Biomass materials such as empty fruit bunch (EFB), mesocarp fibre (MF) and palm shell (PKS) were torrefied and pyrolyzed. The experiment conditions were set to be respectively at 220 o C of temperature, 10 o C/min of heating rate and 30 minutes holding time for torrefaction and at 650 oC of temperature, 20 o C/min heating rate and  2 hours holding time for pyrolysis. Nitrogen flow rate of 2L/min was maintained for both experiments. The torrefied biomass contains high carbon content and low oxygen content than the raw biomass. Also, the biochar derived from torrefied biomass have high fixed carbon content than the biochar derived from untorrefied biomass. The maximum higher heating value (HHV) of about 31.2 MJkg-1 is obtained in the biochar derived from the torrefied shell. Though, all the biomass materials used in this research have exhibited a positive outcome after being torrefied and pyrolyzed. It is clear from scanning electron microscopy (SEM) images that the biochar (b) and (d) derived from torrefied biomass could be better in the application of soil amendment and water retention due to a large number of uniform holes. Therefore, it can be concluded that pyrolysis of torrefied biomass improved the quality of biochar than the biochar obtained from untorrefied biomass.
The Laplacian energy of conjugacy class graph of some dihedral groups
Authors: Mahmoud Rabiha Birkia , Sarmin Nor Haniza , Erfanian Ahmad , Ahmad Fadzil Amira Fadina
Published: October 2017

Let G be a dihedral group and Gamma its conjugacy class graph. The Laplacian energy of the graph, LE(Gamma) is defined as the sum of the absolute values of the difference between the Laplacian eigenvalues and the ratio of twice the edges number divided by the number of vertices. In this research, the Laplacian matrices of the conjugacy class graph of some dihedral groups and its eigenvalues are first computed. Then, the Laplacian energy of this graph is determined.
The adjacency matrix of the conjugate graph of metacyclic 2-groups
Authors: Alimon Nur Idayu , Sarmin Nor Haniza , Ahmad Fadzil Amira Fadina
Published: October 2017

Let G be a metacyclic 2-group and gamma(conj,G) is the conjugate graph of G. The vertices of gamma(conj,G) are non-central elements in which two vertices are adjacent if they are conjugate. The adjacency matrix of gamma(conj,G) is a matrix A=[a(i,j)] consisting 0's and 1's in which the entry a(i,j) is 1 if there is an edge between ith and jth vertices and 0 otherwise. In this paper, the adjacency matrix of a conjugate graph of metacyclic 2-groups is presented.
Multiscale boundary element method for Poisson’s equation
Authors: Zulkefli Nor Afifah Hanim , Yeak Su Hoe , Ismail Munira
Published: October 2017

This paper applied the multiscale boundary element method for the numerical solution of the Poisson equation. The multiscale technique coupling with boundary element method will be used to solve the problem of Poisson equation efficiently and faster. Numerical example is given to illustrate the efficiency of the propose method. The solution of proposed method will be compared with boundary element method and the former method show less iteration in computation.
Effect of gravity modulation on mixed convection flow of second grade fluid with different shapes of nanoparticles
Authors: Rawi Noraihan Afiqah , Ilias Mohd Rijal , Mat Isa Zaiton , Shafie Sharidan
Published: October 2017

The problem of unsteady mixed convection flow of second grade fluid over an inclined stretching plate under the influence of different shapes of nanoparticles is studied in this paper. The influence of gravity modulation is also considered. Carboxymethyl cellulose solution (CMC) is chosen as the non-Newtonian base fluid. Based on Tiwari-Das nanofluid model, the governing partial differential equations are transformed into a system of ordinary differential equations and solved numerically using an implicit finite difference scheme. The effect of different shapes and volume fraction of solid nanoparticles on the enhancement of convective heat transfer of second grade nanofluid associated with the effect amplitude of modulation, frequency of oscillation, and material parameter is discussed in details. The results indicated that, the needle-shaped nanoparticles give the highest enhancement on the heat transfer of second grade nanofluid compared to sphere and disk-shaped nanoparticles.
Direct synthesis of ZSM-5 from kaolin and the influence of organic template
Authors: Prasetyoko Didik , Rustam Rustam , Ediati Ratna , Septiyana Berty , Zein Yusuf Muhammad , Bahruji Hasliza , Qoniah Imroatul , Hartati Hartati , Nur Hadi
Published: October 2017

We investigated the transformation of kaolin to ZSM-5 using hydrothermal synthesis method and the influence of organic template as a structure-directing agent.  The formation of ZSM-5 from kaolin occurred via dissolution of kaolin to form amorphous silica. Zeolite-like analcime produced when the hydrothermal treatment was extended to 18 h. We found synergistic effect of using a mixture of TPAOH and TPABr organic template to enhance kaolin dissolution, initiate ZSM-5 formation and inhibit the transformation of ZSM-5 to analcime.
Microstructure and superconducting properties of Ag-substituted YBa2-xAgxCu3O7- δ ceramics prepared by sol-gel method
Authors: Ramli Fariesha Farha , Abd Wahab Norazidah , Hashim Azhan
Published: October 2017

Superconductor YBa2-xAgxCu3O7- δ in a bulk form has been developed through modified sol-gel processing. The preparation involved dissolving metal organic precursor in a mixture of propanoic acid and propylamine which then undergo for annealing at 900 °C for 5 hours and sintering at 950 °C for 5 hours. The bulk samples were characterized using X-ray diffractogram (XRD), resistivity measurement technique and Scanning Electron Microscope (SEM). The highest TC value was found at 84 K for x=0.05. The value decrease as the Ag concentration increase. The highest JC value measured for x =0.05 were 5.977 A/cm2 at 50 K and 4.748 A/cm2 a 60 K. 123 phase remains as orthorhombic for all samples. SEM micrograph showed the clear grains for the pure samples and it became not visible as the Ag concentration increase.
Fast ensemble empirical mode decomposition model for forecasting crude oil and condensates
Authors: Akrom Nuramirah Binti , Ismail Zuhaimy
Published: October 2017

Crude oil and condensates supply and demand strives to be main authority of the sustenance of almost all country’s economy. The sudden rise in the oil price has forced the government to forecast the supply and demand of crude oil and condensates in order to make sure that the amount of crude oil meets the supply and demand of the country. Accurate forecasts can save cost, foresee scarcity of demand, and help in budgeting profit. In addition, predicting crude oil and condensate data is frequently proven to be a demanding task considering the various intricacies of oil data pattern. The main objective of this study was to forecast crude oil and condensates demand data in Malaysia using Fast Ensemble Empirical Mode Decomposition (FEEMD) model. The forecasting process using FEEMD model was performed in order to achieve the most desirable forecast accuracy of the crude oil and condensates data. The FEEMD model is an extension of the Empirical Mode Decomposition (EMD) model whereby white noise signal was added to the existing signal in the sifting process. The effectiveness of the proposed forecasting method was compared to other traditional models of ARIMA, ARIMAX and GARCH. The results revealed that the proposed FEEMD method for forecasting crude oil and condensates data was very promising as it achieved good forecast accuracy.
The independence polynomial of n-th central graph of dihedral groups
Authors: Najmuddin Nabilah , Sarmin Nor Haniza , Erfanian Ahmad , Rahmat Hamisan
Published: October 2017

An independent set of a graph is a set of pairwise non-adjacent vertices while the independence number is the maximum cardinality of an independent set in the graph. The independence polynomial of a graph is defined as a polynomial in which the coefficient is the number of the independent set in the graph.  Meanwhile, a graph of a group G is called n-th central if the vertices are elements of G and two distinct vertices are adjacent if they are elements in the n-th term of the upper central series of G. In this research, the independence polynomial of the n-th central graph is found for some dihedral groups.
Optimization of reflector antennas in radio telescopes
Authors: Yeap Kim Ho , Lai Koon Chun , Ting Kung Chuang , Teh Peh Chiong , Nisar Humaira , Yeo Wei Long
Published: October 2017

We present an analysis on the performance of Cassegrain reflector antennas. In our study, we have adopted the design parameters for the Cassegrain configuration used in the Atacama Large Millimeter Array (ALMA) project. We have adjusted the focal-length-to-diameter ratio f/D of the primary reflector to investigate the optimum performance of the antenna. In our study, signal frequency at the high edge of ALMA band 1, i.e. 45 GHz has been selected. The results obtained from the physical optics simulation show that the aperture efficiency of the antenna is at its optimum (i.e. 80.36%) when f/D ranges from 0.5 to 0.6. The radiation characteristics at this range of ratio are found to be similar. The radius of the secondary reflector and edge taper Te which correspond to the optimum aperture efficiencies ranges from 371 mm to 372 mm and 10.64 dB to 10.75 dB, respectively.
Magnetic and microwave absorption properties of nickel ferrite (NixFe3-xO4) by HEM technique
Authors: Yunas Yunasfi , Adi Wisnu Ari , Mashadi Mashadi , Rahmy Putri Astari
Published: October 2017

Nickel ferrite (NixFe3-xO4) have been synthesized using solid state reaction with composition (2x)NiO : (3-x)Fe2O3 (x = 0.5; 1.0; 1.5 dan 2.0) in mol in wt%. Mixing of this powder was milled with HEM (High Energy Milling) for 10 hours, and then sintered at 1000 °C for 3 h. X-ray diffraction pattern indicates that the all of samples are single phase in this stage. FTIR (Fourier transform infrared) analysis showed two absorption bands in the range of ~410 - ~600 cm-1 related to octahedral and tetrahedral sites. The magnetic measurement using vibrating sample magnetometer (VSM) shows that the sample exhibited a ferromagnetic behaviour with its coercivity value in the range of 164-217 Oe, and the maximum value wasshowed by x =1.5. VNA (Vector Network Analyzer) characterization shows the ability electromagnetic wave absorption with RL (reflection loss) value of -28 dB occurs at frequency of 10.98 GHz. It means that the Ni1.5Fe1.5O4 sample can absorb microwave about ~96 % at 10.98 GHz.
Brucea javanica seeds as source of potential natural antioxidants to improve biodiesel thermal and oxidative stability
Authors: Hasni Khalil Ullah , Zulkiflee Lubes Zul Ilham , Mohamad Jamaludin , Varman Mahendra
Published: October 2017

Biodiesel is one of the most promising renewable energy derived from biological sources. Biodiesel is clean and renewable biofuel but its oxidative stability is low. To increase oxidative stability of biodiesel, natural antioxidants are considered as potential compounds to be used. The purpose of the  work was to investigate and determine the antioxidation potential of Brucea javanica seeds by applying different antioxidant assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), metal chelating and ferric reducing antioxidant power (FRAP). Furthermore, Total phenolic content (TPC) and Total flavonoid content (TFC) tests were done. Among the three extracts of Brucea javanica seeds, ethyl acetate extract showed the highest total phenolic content (98.5 ±0.1mg GAE/g dry extract). The highest total flavonoid content (20 ± 0.4mg QAE/g of dry weight) and DPPH inhibition activity 90%. Ethyl acetate extract also exhibited the highest chelating activity with 59% inhibition in the metal chelating assay. However, the Rancimat showed a maximum of 69hour induction period (IP) in biodiesel when gallic acid is added.
Improved absorbance of holmium activated magnesium-zinc-sulfophosphate glass
Authors: Jupri Siti Aishah , Ghoshal Sib Krishna , Omar Muhammad Firdaus , Sharma Sunita
Published: October 2017

Constant efforts are dedicated to overcome the limitations of phosphate based glass system, where sulfophosphate glasses (SPGs) played a key role. Rare earth ions (REIs) doped magnesium zinc SPG (MZSPG) systems are technologically prospective due to their several unique attributes. Construction of integrated light ampliﬁer and solid state laser needs the maximum gain within small component dimensions. Thus, Ho3+ ions doped SPGs are believed to meet this demand. Ho3+ ions having sharp optical absorption peaks in the spectral range of 200–900 nm is useful for diversified applications. Conversely, SPGs comprising of oxides of sulphur, phosphorous and at least one other component with SO42- ions contents lower than PO43- with low melting temperature makes them a distinctive class of technologically potential disordered system. In this view, modification of Ho3+ ions absorbance inside SPGs network is challenging. To achieve this goal, following melt-quenching route we prepared a series of Ho3+-doped MZSPG system of composition (60-x)P2O5-(20)ZnSO4-(20)MgO–(x)Ho2O3, where x = 0.0, 0.5, 1.0, 1.5 2.0, and 2.5 mol%. The influence of Ho2O3 concentration on the density, refractive index, and optical absorption properties of the synthesized glass system is examined. The density and refractive index is found to increase with increasing Ho2O3 concentration. The absorption spectra revealed nine prominent peaks centered at 387, 418, 450, 484, 538, 642, 1148 and 1945 nm. The glass absorbance is enhanced with increasing Ho3+ contents. Optical band gap energy is found to range from 3.847 to 3.901 eV. The reduction of Urbach energy from 0.257 to 0.191 eV with increasing Ho3+ contents verified the shrinkage of glass network structure and lowering of defect mediated disorder. In-depth investigations on the structural and optical properties of MZSPG system are underway to achieve the milestones set for photonic devices.
Modified absorption attributes of neodymium doped magnesium-zinc-sulfophosphate glass
Authors: Yusof Nur Nabihah , Ghoshal Sib Krishna , Omar Muhammad Firdaus
Published: October 2017

Rare-earth doped glass systems with improved absorption and emission features are greatly demanding for diverse applications. In this endavour, selection of right glass host, modifier, rare earth ions with optimized composition is the key issue. This communication reports the conventional melt-quench synthesis of neodymium (Nd3+) doped magnesium-zinc- sulfophosphate glass system of the form (60-x)P2O5-20MgO-20ZnSO4-xNd2O3 (x = 0, 0.5, 1, 1.5, 2.0 and 2.5 mol%). The influence of varying Nd3+ contents on the physical (density, molar volume, molar refractivity, refractive index and electronic polarizability) and absorption properties of the prepared glass system is determined. The amorphousity of the obtained samples is confirmed by XRD analysis. The glass refractive indices (ranged from 1.85 to 1.90)  and densites (between 2.63 to 2.77 g.cm-3) are found to increase with increasing concentration of Nd3+ ion. Furthermore, the energies associated with the direct and indirect optical transitions across the forbidden gap are observed to reduce with the increase of Nd3+ ion concentration. Meanwhile, the increase of Urbach energy with increasing Nd3+doping is ascribed to the interaction of rare earth ions with the ligands of the glass network and subsequent transformation of weak bonds into defects. The room temperature UV–Vis-NIR spectra revealed eleven absorption band corresponding to the transitions from the ground state to various excited states of the Nd3+ ion. Incorporation of  Nd3+ ion is discerned to enhance the glass absorbance appreciably together with the alteration of physical properties. Present findings may be beneficial for the advancement of Nd3+ ions doped magnesium-zinc-sulfophosphate glass system based photonic devices especially for infrared solid state laser.
MHD free convection flow of Casson fluid over a permeable nonlinearly stretching sheet with chemical reaction
Authors: Ullah Imran , Shafie Sharidan , Khan Ilyas
Published: October 2017

The problem of heat and mass transfer free convection flow of Casson fluid over a porous nonlinear stretching sheet in the presence of chemical reaction is investigated. Moreover the effect of magnetic field is also considered. The governing partial differential equations are transformed into ordinary differential equations by making use of suitable transformations and then solved numerically via Keller-box method. The results for skin friction are compared with previous results of the existing literature. The results are also reflected in good agreement. It is noted that concentration of Casson fluid reduces rapidly by increasing Schmidt number and chemical parameter. Also, thermal Grashof number and mass Grashof number enhance the momentum boundary layer thickness, whereas increment in chemical reaction parameter reduces the heat transfer rate. Moreover, both the fluid velocity and wall shear stress are observed to be decreased with increment in suction/blowing parameter.
Binary metal oxides supported on γ-Al2O3 for application in transesterification of low-grade cooking oil
Authors: Sulaiman Nur Fatin , Wan Abu Bakar Wan Azelee , Ali Rusmidah
Published: October 2017

Recently, the production of biodiesel has increased greatly due to the less harmful effects of this fuel towards the environment which is sourced from renewable materials compared to a conventional diesel. The series of solid base catalysts, binary metal oxide (Cu/Zn) were synthesized by the modified wet impregnation method supported on γ-Al2O3.The investigation of Cu/Zn/γ-Al2O3 catalyst on the calcination temperature, copper loading and number of alumina coatings had significantly affected the catalytic performance. The optimum conditions from experimental data were achieved with 10 wt.% of Cu loading of Cu/Zn/γ-Al2O3 catalyst calcined at 800°C with 3 times number of alumina coatings exhibited the highest fatty acid methyl ester (FAME) yields, 87.07% at mild reaction conditions (65°C, atmospheric pressure, 1:20 methanol-to-oil molar ratio, 10 wt.% of catalyst loading and 2 hours of reaction time). The physicochemical properties studied by BET surface area of Cu/Zn(10:90)/γ-Al2O3 catalyst calcined at 800°C which gave high surface area, 149.32 m2/g. FESEM-EDX analysis of Cu/Zn(10:90)/γ-Al2O3 catalyst indicated the amorphous in structure with undefined shapes and mixture of larger and smaller particles sizes. The production of biodiesel and the percentage conversion of FAME was analyzed by using GC-FID in the presence of methyl palmitate, cis-9-oleic acid methyl ester and methyl linoleate.
Effect of strontium concentration on thermoluminescence glow curve of copper doped lithium magnesium borate glass
Authors: Salleh Nurul Anati , Tamuri Abdul Rahman , Saeed Mohamad Alam
Published: October 2017

This study investigates the thermoluminescence (TL) properties of copper (Cu2O) doped lithium magnesium borate (LMB) glass co-doped with strontium (SrO) subjected to Co-60 gamma irradiation. The glass samples based on (69.95-x)B2O3 – 20Li2O – 10MgO: 0.05Cu2O; xSrO, where 0.001 ≤ x ≤ 0.03 mol% were prepared by melt-quenching technique. The amorphous state of both Sr co-doped and Cu-doped LMB glass samples were confirmed by using X-Ray Diffraction (XRD). For this study, the optimum TL Response was found with 0.003 mol% of Sr concentration with TL intensity 3.6 x 105 nCg-1. The maximum peak temperature of glow curve for all glass samples was observed at 170-200 oC. The annealing procedure for the studied samples was determined at 100 oC for 20 minutes with the heating rate of 7 oC s-1.
Estimation of rainfall and stream flow missing data for Terengganu, Malaysia by using interpolation technique methods
Authors: Wan Ismail Wan Norliyana , Wan Zin @ Wan Ibrahim Wan Zawiah
Published: October 2017

Missing data is a serious problem in many climatological time series. Daily rainfall and stream flow datasets with no missing values are required for efficient estimation for application purposes. In order to estimate any missing observations in data, interpolation techniques are often used. This study focuses on comparing a few selected methods in the estimation of missing rainfall and stream flow data. The interpolation techniques studied were the Arithmetic Average (AA) method, Normal Ratio (NR) method, Inverse Distance (ID) method and Coefficient of Correlation (CC) method. However, in the case when there is no information from neighboring stations, the mean on the same day and month but at different years is taken as estimation of the missing value on that particular date. Twenty years of daily rainfall and stream flow data at 12 stations located at Terengganu were used for this study. In testing to verify which method is the best in evaluating missing values at the target station using information from the nearby stations (in the radius range of 10 km to 50 km), several percentages of missing values were considered. The validation of the best estimation methods is done based on the estimation error; with tests such as Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Correlation Coefficient (R) tests.
Electronic properties of palladium diselenide by density functional theory
Authors: Ng Ying Xuan , Ahmed Rashid , Lawal Abdullahi , Ul Haq Bakhtiar , Radzwan Afiq , Kasmin Mohd Khalid
Published: October 2017

The knowledge of the structural and electronic properties of a material is important in various applications such as optoelectronics and thermoelectric devices. In this study, we are using full potential linearized augmented plane wave method framed within density functional theory provided by WIEN2k to optimize the structure of PdSe2 in orthorhombic (Pbca) phase and calculate its electronic properties. With the implementation of local density approximation (LDA), Perdew-Burke-Ernzerhof parameterization of generalized gradient approximation (PBE-GGA), Wu-Cohen parameterization of GGA (WC-GGA), and PBE correction for solid GGA (PBEsol-GGA), the computed results of lattice constants are found to be within 5% error with the experiment data. Also, our calculated indirect band gap energy was found to be ~0.24 eV by LDA along with modified Becke-Johnson potential functional (mBJ) with experimental lattice constants and ~0.52 eV by using PBE-GGA with optimized lattice constants. However, the effect of spin-orbit coupling is not found too much on the band gap energy. By analyzing the partial density of states, we identify that d-orbital of Pd is demonstrating a slightly more significant contribution to both the valence and conduction band near to Fermi level which is also in agreement with the previous first principles study.
Aligned magnetic field on dusty Casson fluid over a stretching sheet with Newtonian heating
Authors: Arifin Nur Syamilah , Mohd Zokri Syazwani , Mohd Kasim Abdul Rahman , Salleh Mohd Zuki , Mohammad Nurul Farahain , Wan Yusoff Wan Nur Syahidah
Published: October 2017

Boundary layer flow and heat transfer on Casson fluid with dust particle over a stretching sheet is numerically investigated. The influences of aligned magnetic field together with Newtonian heating are considered in this problem. The governing equations are first transformed into ordinary differential equations using the appropriate similarity transformation variables. The numerical computation using Runge-Kutta Fehlberg (RKF45) method is employed to generate the results. Several physical parameters for both phases (fluid and particle) such as aligned angle, magnetic field parameter, Casson parameter, fluid particle interaction parameter, Prandtl number and conjugate parameter are investigated and analysed. The results in term of distribution velocity and temperature are presented graphically. The finding revealed that a rise in aligned angle and magnetic field parameter led to decrease the velocity profile and increase the temperature profile for both phases.
Thermoluminescence (TL) response of silica nanoparticles subjected to 50 Gy gamma irradiation.
Authors: Mohamed Abdul Ghani Nik Noor Aien , Saeed Mohammad Alam , Hashim Izyan Hazwani
Published: October 2017

Thermoluminescence (TL) response of silica nanoparticles synthesized by the sol-gel method is presented here. Transmission electron microscopy (TEM) was used to find out the size and morphology of the pure silica nanoparticles. By using an appropriate amount of tetraethylorthosilicate, ethanol, deionized water and ammonia solution, silica samples were synthesized. To determine the best TL response of silica, samples were irradiated with 50Gy gamma rays. The effect of size dependency towards TL yield indicates that decreasing the particles’ size of silica, increases the TL yield.
Rheological and physicochemical characterization of alpha-tocopherol loaded lipid nanoparticles in thermoresponsive gel for topical application
Authors: Ying Lim Qian , Misran Misni
Published: October 2017

Features of a thermoresponsive gel is advantageous in topical application. Lipid nanoparticles is incorporated as a carrier for hydrophobic active ingredient which is not stable in the aqueous gel system. In this work, a thermoresponsive gel mixture consists of carboxymethyl cellulose (CMC) and iota-carrageenan (ι-C) was prepared. Nanostructured lipid carriers (NLC) made of fatty acids and lecithin was incorporated into the gel formulation as a carrier for alpha-tocopherol. Temperature effect on rheological behavior of the prepared gel mixture was investigated. The NLC was evaluated for its mean particle size, zeta potential, morphology, encapsulation efficiency and in vitro drug release. Physicochemical characterization showed that alpha-tocopherol loaded NLC being stored at 4 ˚C was stable for 1 month and encapsulation efficiency of alpha-tocopherol was more than 90 % for all formulations due to its hydrophobicity to stay in the lipid matrix. In vitro release studies proved that NLC was able to provide slow release of loaded alpha-tocopherol. On the other hand, the phase transition from gel-like to liquid-like of the formulated gel mixture was proven to be activated by temperature changes. The rheological gelling point of the gel mixture was represented by the crossover point of storage modulus, G’ and loss modulus, G’’ which was obtained in the vicinity of body temperature 37 ˚C. This property is useful in topical application for its better spreadability on skin upon usage and hence better penetration for the alpha-tocopherol loaded NLC across skin barrier. Prolong release of alpha-tocopherol with enhanced stability is favored as alpha-tocopherol is commonly known for its potent antioxidant activities. These results suggested that gel mixture of CMC and ι-C is a good candidate to be developed as a thermoresponsive gel while lipid nanoparticles is a promising carrier system for alpha-tocopherol in topical use.
First-principles calculations of antimony sulphide Sb2S3
Authors: Radzwan Afiq , Ahmed Rashid , Shaari Amiruddin , Lawal Abdullahi , Xuan Ng Ying
Published: October 2017

The structural, electronic and optical  properties of Sb2S3 have been investigated  using full-potential linearized augmented plane wave method within density functional theory (DFT) framework, treating exchange-correlation potential with Engel-Vosko generalized gradient approximation (EV-GGA). Electronic properties calculations were performed  with and without taken into account the effects of spin-orbit coupling (SOC) . From our results we found that structural properties,density of states and band structure are in good agreement with experimental results.The effects of SOC and relativistic on electronic properties were found to be negligible. However, optical properties, namely, imaginary and real parts of dielectric function, reflectivity, absorption coefficient, refractive index, extinction coefficient and energy loss function were calculated and analyized.Optical gap of 1.61 eV proves that Sb2S3 metal chalcogenides is a promising material for solar cell device.
Examine generalized lambda distribution fitting performance: An application to extreme share return in Malaysia
Authors: Marsani Muhammad Fadhil , Shabri Ani , Mat Jan Nur Amalina
Published: October 2017

Understand the extreme volatility in the market is important for the investor to make a correct prediction. This paper evaluated the performance of generalized lambda distribution (GLD) by comparing with the popular probability distribution namely generalized extreme value (GEV), Generalized logistic (GLO), generalized Pareto (GPA), and Pearson (PE3) using Kuala Lumpur composite index stock return data. The parameter for each distribution estimated using the L-moment method. Based on k-sample Anderson darling goodness of fit test, GLD performs well in weekly maximum and minimum period. Evidence for preferring GLD as an alternative to extreme value theory distribution also described.
Antibacterial finishing of a dyed cotton fabrics using diospyros mespiliformis leaves extracts
Authors: Balarabe Sulaiman , Habibu Shehu , Gumel Sani Muhammad , Ladan Magaji , Birniwa Abdullahi Haruna , Koki Isa Baba , Usman Sharif Nafiu
Published: October 2017

In this study, leaves of Diospyros mespiliformis was extracted using ethanol and macerated with chloroform and ethyl acetate and later screened for antibacterial  properties. The antibacterial analysis was performed qualitatively via disc diffusion method (AATCC 147) against Escherichia coli and Staphylococcus aureus as gram negative and gram positive bacteria respectively. The extract shows a significant activity on the isolated micro-organisms as evidenced by a clear zone of inhibition, more so in the ethyl acetate petri dish indicating its potentials in preventing microbial growth. The extract was then used to dye cotton fabrics by pre-mordanting, simultaneous mordanting and post-mordanting processes. The materials were assessed for fastness properties, such as fastness to washing, light, pressing and rubbing based on AATCC standards. The results show a good to moderate fastness properties suggesting that extract of Diospyros mespiliformis can be successfully used for dyeing of cotton fabric in textile industries thereby reducing the pollution and environmental hazards associated with the use of conventional synthetic chemical dyes.
On the generalized commuting and non-commuting graph for metacyclic 3-groups
Authors: Zamri Siti Norziahidayu Amzee , Sarmin Nor Haniza , El-Sanfaz Mustafa Anis , Rahmat Hamisan
Published: October 2017

Let   be a metacyclic 3-group and let   be a non-empty subset of   such that  . The generalized commuting and non-commuting graphs of a group   is denoted by   and   respectively. The vertex set of the generalized commuting and non-commuting graphs are the non-central elements in the set   such that     where   Two vertices in   are joined by an edge if they commute, meanwhile, the vertices in   are joined by an edge if they do not commute.
Hydromagnetic boundary layer flow of a dusty fluid in a porous medium over a stretching sheet with slip effect
Authors: Md Shab Noorzehan Fazahiyah , Ali Anati
Published: October 2017

This paper investigated the problem of hydromagnetic boundary layer flow and heat transfer of a dusty fluid over a stretching sheet through a porous medium. The velocity slip was considered instead of the no-slip condition at the boundary. The governing partial equations were reduced into a set of non-linear ordinary differential equations by using the suitable similarity transformation. The transformed equations were numerically integrated using bvp4c in Matlab. The effects of various physical parameters on the velocity and temperature profiles of both phases, such as fluid-particle interaction parameter, magnetic parameter, mass concentration parameter, porosity parameter and Prandtl number were obtained and analyzed through several plots. Useful discussions were carried out with the help of plotted graphs and tables. Under the limiting cases, the obtained numerical results were compared and found to be in good agreement with previously published results.
Influence of radiation and viscous dissipation on magnetohydrodynamic Jeffrey fluid over a stretching sheet with convective boundary conditions
Authors: Zokri Syazwani Mohd , Arifin Nur Syamilah , Mohamed Muhammad Khairul Anuar , Salleh Mohd Zuki , Kasim Abdul Rahman Mohd , Mohammad Nurul Farahain
Published: October 2017

The present paper focuses on the influence of radiation and viscous dissipation on magnetohydrodynamic (MHD) flow and heat transfer of a Jeffrey fluid over a stretching sheet with convective boundary conditions (CBC). The governing equations are reduced to non-linear ordinary differential equations by using similarity transformation variables and then solved by using Runge-Kutta-Fehlberg method. The results generated from the numerical computations are presented in the form of tables and graphs for some values of Deborah number, ratio of relaxation to retardation times, Eckert number, radiation parameter and magnetic parameter. It is found that the distribution of fluid velocity is noticeably increased with an increment in Deborah number while the distribution of temperature shows the opposite trend.
Mechanization of the Sturmfel-Salmon resultant method
Authors: Sulaiman Surajo , Aris Noraini , Ahmad Shamsatun Nahar
Published: October 2017

Designing and implementing a procedure for computing the polynomial resultant provides an avenue for analyzing both the computational complexity and performance of such construction. In this paper a new Maple procedure called Sturmfelmethod for computing the Sturmfel-Salmon resultant method is proposed based on existing methods and assumptions. Examples are provided to demonstrate the mechanization of the resulting new algorithm and its computing time. The new procedure can be used to determine whether three polynomials intersect or not and to solve a given system of polynomial equations.