bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Gas Emission Quantity Based on Least Square Support Vector Machine
Authors: Yuan Jun Wei , Wang Kai , Jiang Xiao Gai
Published: December 2012

Gas emission quantity has been affected by several natural factors and development of technology, which is a nonlinear and high-dimension problem. By using least square support vector machine (LSSVM), gas emission quantity in mined- out working face has been calculated, and then it has been compared and analyzed with measurement. Besides, gas emission quantity in pre-mining has been predicted. The results indicate that the higher the prediction accuracy of LSSVM is, the stronger the generalization is.
Study of Mine Air Compressors’ Remote Monitoring and Fault Diagnosis Expert System
Authors: Wang Hui , Wang Hai Jian , Zhao Di , Yang Lin
Published: December 2012

In order to improve the degree of automation of the mine air compressor system, To achieve the remote monitoring and real-time fault diagnosis of the mining air compressors, using Siemens PLC as the data acquisition hardware platform, the host computer using the software of the Kingview and Power Builder9.0 construct the air compressors remote monitoring and fault diagnosis expert system platform, To achieve the remote air compressors parameters real-time acquisition, display, fault diagnosis, as well as remote start and stop the air compressors ,loading and unloading control, while the air compressors room remote real-time monitoring, ensure the security and stability of the air compressors system.
Dislocation Distribution Functions of the Edges of Mode I Crack under Several Boundary Conditions
Authors: Wang Yun Tao , Lü Nian Chun , Wang Chao Ying , Cheng Jin
Published: December 2012

Dislocation distribution functions of mode I dynamic crack subjected to two loads were studied by the methods of the theory of complex variable functions. By this way, the problems researched can be translated into Riemann-Hilbert problems and Keldysh-Sedov mixed boundary value problems. Analytical solutions of stresses, displacements and dynamic stress intensity factors were obtained by the measures of self-similar functions and corresponding differential and integral operation. The analytical solutions attained relate to the crack propagation velocity and time, but the solutions have nothing to the other parameters. In terms of the relationship between dislocation distribution functions and displacements, analytical solutions of dislocation distribution functions were gained, and variation rules of dislocation distribution functions were depicted.
Growth of Nanocrystalline PbS Thin Films by Solid-Vapor Deposition
Authors: Obaid A.S. , Mahdi M.A. , Zainuriah Hassan
Published: December 2012

Solidvapor deposition was used to synthesize nanocrystalline PbS thin films on a Si (100) substrate. Lead sulfide (PbS) powder was first prepared and then heated to 1050 °C in a tube furnace. The resulting vapor was carried to the substrate zone by an argon flow. The structure of the nanocrystalline PbS thin films was determined by X-ray diffraction (XRD). The grain size of the PbS thin films and powder was also estimated by XRD. The surface morphology and stoichiometric ratio of these ingots were observed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. The SEM image revealed that the film had a uniform surface morphology over the entire substrate. The optical absorbance of the deposited films and powder were measured by Fourier-transform infrared spectroscopy. The optical band gap Eg of the samples was calculated using the Tauc formula. The absorption of the thin films was found to be higher than that of the powder and lower for the entire wavenumber range (15005000 nm). The Eg values of the films determined were 3647 nm (0.34 eV), and that of the powder was 3100 nm (0.40 eV).
The Effects of Combustion Agents on the Formation of Bi-Based Compounds Synthesized Using the Soft Combustion Method
Authors: Razak Khairunisak Abdul , Anuar Mohamad Afifi , Ng Chai Yan
Published: December 2012

In this work, 20 % Pr doped bismuth sodium titanate (PBNT) powders were synthesized using the soft combustion technique. Three combustion agents; polyethylene glycol 200, citric acid and glycine with 0.2, 2.0 and 5.0 mol were used to aid combustion process. A single phase PBNT was obtained with the addition of 5 mol % citric acid. For most compounds, secondary phases presence such as Bi4Ti3O12 and Bi2Ti2O7. In general, crystallite size increased with increasing sintering temperature that was due to diffusion of ions at high temperature. Dielectric properties increased with increasing densities. The optimum properties were obtained for PBNT synthesized using 5 mol % citric acid sintered at 1100°C for 3 hours which gave the highest dielectric constant (1153.20), acceptable loss tangent (0.1074) and high relative density (95.03).
Study on the Influence of Synthesis Temperature of Anatase TiO2 Nanoparticles for Electrophoretic Deposition
Authors: Yaacob Khatijah A. , Riley Jason D.
Published: December 2012

The purpose of this research is to study the effect of synthesis temperature in order to produce anatase TiO2 nanoparticles (NPs) without using strong acids. In this research TiO2 nanoparticles was prepared by the hydrolysis and condensation of titanium (IV) isopropoxide in water at synthesis temperature of 0°C ± 0.1°C which produced anatase TiO2 crystallite size of 4.66 nm. XRD (X-ray diffraction) was used to analyse the crystal structure of the TiO2 and to calculate the crystallite size of the TiO2 nanoparticles. Transmission electron microscope (TEM) was also used to characterise the morphology of the TiO2 nanoparticles.
XRD Analysis of Cu-Al Interconnect Intermetallic Compound in an Annealed Micro-Chip
Authors: Chua Kok Yau , Hng May Ting , Lee Cher Chia , Anand T. Joseph Sahaya
Published: December 2012

Cu-Al intermetallic compound (IMC) in Cu wire-Al bond pad interconnect interface is drawing attention of researches. However, due to thin IMC thickness, the characterizations of the IMC are limited to expensive and time consuming techniques. An evaluation is performed to use common X-Ray Diffraction (XRD) technique to identify the IMC in the Cu wired micro-chip samples in powder form. Existence of mixture of CuAl and CuAl2 was first confirmed by transmission electron microscope (TEM) and energy dispersive X-ray (EDX). In XRD analysis, peak correspond to CuAl phase is identified from measurement with slower scan configuration. The difficulty for IMC peak detection in diffractogram is due to low composition ratio of IMC relative to other materials available in the sample. KOH treatment for enhancing IMC peaks intensity does not work as expected as it etches the IMC as well.
Discovery of WO3/TiO2 Nanostructure Transformation by Controlling Content of NH4F to Enhance Photoelectrochemical Response
Authors: Lai Chin Wei , Sreekantan Srimala
Published: December 2012

We report on the effect of the tungsten (W) cathode in controlling the morphology and properties of titanium (Ti) anodic oxide layer via an electrochemical anodization process. The content of ammonium fluoride (NH4F) was varied in ethylene glycol (EG) electrolyte containing hydrogen peroxide (H2O2) in order to obtained the high ordered nanotubular structure. When amount of NH4F was upto 5 wt%, highly ordered WO3-TiO2 nanotubes structure was observed. If insufficient amount of NH4F is applied, the nanoporous structure will be favored. Highly ordered WO3-TiO2 nanotubes structure exhibited higher photocurrent density ( 0.9 mA/cm2) as compared to the WO3-TiO2 nanoporous structure.
X-Ray Diffraction Study of High Velocity Oxy-Fuel (HVOF) Sprayed Cr3C2-NiCr Coating
Authors: Kaur Manpreet , Singh Harpreet , Prakash Satya
Published: December 2012

Among the various characterization techniques, X-ray diffraction (XRD) analysis is a key method which reveals various phases and protective oxides formed on the surfaces of exposed specimens. This paper discusses the XRD study of two boiler steels, namely ASTMSAE213-T22 and SAE-347H with and without High Velocity Oxy-fuel (HVOF) spray Cr3C2-NiCr coating, which were exposed to air, molten salt [Na2SO4-82%Fe2(SO4)3], and actual boiler environments. XRD analysis has been discussed and the results obtained from the analysis are shown. The performance of the steels was found to improve after the deposition of the coating, which may be attributed to the formation of protective phases.
The Effect of Stoichiometry to the Phase Formation of Barium Titanate
Authors: Faris Meor Ahmad , Yeoh Cheow Keat , Arif Wan Mohd , Teh Pei Leng , Abdullah Nadia
Published: December 2012

This paper focus on the effect of different ratio between barium (Ba) and titanium (Ti) to the production of high purity of barium titanate (BT). On this research, the sample was prepared by solid-state reaction between barium carbonate (BaCO3) and titanium dioxide (TiO2) powder at constant sintering temperature of 1350 °C. The sample was prepared at different ratio of Ba:Ti which are 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1. All sintered BT was characterized by X-ray diffraction (XRD). All existed phase on these samples was determined and analyzed. Sample from ratio 1:1 produced almost a single phase of BT. While; samples from other ratio produce secondary phase which is barium orthotitanate (Ba2TiO4).
Heterogeneous Combustion of Ti/Si/C Powders with Estimated Ti3SiC2 Routes Morphologies
Authors: bin Abu Mohamad Johari , Mohamed Julie Juliewatty , Ahmad Zainal Arifin
Published: December 2012

In this study, about 62.2 wt% Ti3SiC2 was synthesized via tungsten inert gas (TIG) welding method, as potential in advanced material applications. This arced sample was characterized using XRD and FESEM analysis to observe the phase presence, and its morphology. Ti3SiC2 phase favours to form at 5 s and produces elongated platelets (Ti3SiC2) grain, micro-porous equiaxed (TiC) grain and melt regions (Ti-Si), when observed at the dense surfaces. Meanwhile, fine dendrite, quasi-spherical, and pyramidal grains were observed at the pore sites. The laminate dendrite of Ti3SiC2 was estimated to form at the origin of TiC faced pyramidal crystal, which nucleated toward TiC pyramidal crystal surface at the specific angle.
Investigation of Grain Size Effect on the Impedance of CaCu3Ti4O12 from 100 Hz to 1 GHz of Frequency
Authors: Sulaiman Muhammad Azwadi , Hutagalung Sabar Derita , Ahmad Zainal Arifin , Ain Mohd Fadzil
Published: December 2012

CaCu3Ti4O12 (CCTO) is a cubical perovskite phase and sintered ceramics exhibit very high dielectric constant at room temperature. The speculated origins of the high dielectric constant are the existence of insulative barrier layer at grain boundaries and domain boundaries which created an internal barrier layer capacitance (IBLC) at the microstructure of CCTO. The relation of grains and domains electrical resistance were studied in this work by using impedance spectroscopy (IS). A series of samples with different heat treatment temperature were tested to investigate their microstructure by using field emission scanning electron microscopy (FESEM). The grains and domains resistance was calculated from a wide frequency range of impedance complex plane measurement (100 Hz to 1 GHz). The FESEM and IS analyses showed the dependency of grains and domains resistance to average grains size of CCTO microstructure.
Hybrid Multiwalled Carbon Nanotubes/Minerals as Potential Fillers for Polymer Composites
Authors: Kudus Muhammad Helmi Abdul , Hazizan Md Akil , Saleh Siti Shuhadah M.
Published: December 2012

Minerals are always used as filler material in polymer composite application purposely to reduce the price. In order to optimize the use of mineral fillers instead of price reduction, there were several approaches that have been done such as surface treatment, finding suitable coupling agent, and etc. The study on hybridization of minerals with carbon nanotubes (CNT) are rare to be found. CNT has received great attention from researchers due to their superior properties to be used in many applications. Hybridizing CNT with minerals proposes potential fillers for polymer composite. In this study, chemical vapor deposition (CVD) technique was used to synthesize the CNT-minerals hybrid compound. A mixture of CH4/N2 was used as the carbon source and nickel as the metal catalyst for the growth of CNT hybrid compound. Three different types of minerals were used namely talc, muscovite and CaCO3 are used to synthesize the MWCNT-talc, MWCNT-muscovite and MWCNT-CaCO3 hybrid compound. In short, the process involved precipitation of mineral filler with nickel salt. The process was followed by calcinations and reduction of the catalyst, and methane decomposition. The produced hybrid compounds were then analyzed.
Structural and Optical Properties of Nanocrystalline CdO Thin Film Growth by Solid-Vapor Deposition
Authors: Zaien M. , Ahmed Naser Mahmoud , Zainuriah Hassan
Published: December 2012

Nanocrystalline cadmium oxide (CdO) thin film was successfully synthesized by a vapor transport process (solid-vapor deposition) without catalyst. Cadmium powder was heated to 1235 K in a tube furnace, and the resultant vapor was carried to the silicon substrate zone by a flow argon gas with oxygen. Scanning electron microscopy revealed that the product was of nanocrystalline cadmium oxide. X-ray diffraction and energy dispersive X-ray techniques were used to characterize structural properties. The grown nanocrystalline thin film had a grain size of 35 nm. Photoluminescence spectroscopy was conducted to investigate the optical properties of the CdO. The red-shift direct band gap energy of the nanocrystalline CdO was at 511 nm (2.43 eV), whereas that of CdO bulk was at 491 nm (2.5 eV).
X-Ray Diffraction Study of Cold Sprayed Ni-20Cr and Ni-50Cr Coatings on Boiler
Authors: Bala Niraj , Singh Harpreet , Prakash Satya
Published: December 2012

X-ray diffraction (XRD) is a versatile, non-destructive technique that reveals detailed information about the chemical composition and crystallographic structure of materials. In this work Ni-20Cr and Ni-50Cr coatings were deposited on two boiler steels namely T22 and SA 516 steel. The measurement of residual stresses of these cold sprayed coatings was done with the help of X-ray diffraction technique. This paper discussed the XRD study of the as-sprayed coatings. Further the XRD technique was used to study the uncoated and coated steels after cyclic exposure to air, molten salt [Na2SO4-60%V2O5], and actual boiler environments. The results obtained from the XRD analysis have been shown. The weight change results showed that the coated steels performed better than their uncoated counterparts which might be attributed to the formation of protective phases.
Iron Salt Concentration Effect to the Precipitation of Iron Oxide Nanoparticles Conjugated Antibody
Authors: Noorhashimah Mohamad Nor , Khairunisak Abdul Razak , Abdul Aziz Azlan , Noordin Rahmah
Published: December 2012

This study covers the effect of ferrous chloride (FeCl2) concentration on the formation of iron oxide nanoparticles (IONPs) via the precipitation method. IONPs with appropriate surface functionalization were synthesized in order to obtain a stable colloidal IONPs (ferrofluid) for the conjugation process. The electrostatic repulsion using percloric acid (HClO4) and steric stabilization using silane polyethelene glycol (SiPEG) were generated. The optimum concentration of FeCl2 was at 0.3 M. From the transmission electron microscopy (TEM) image, the size of IONPs obtained was ~13 nm. The stable IONPs were then conjugated to the antibody and tested in the lateral flow immunoassay as the labelling agent. The conjugated IONPS with the antibody was proven sensitive to the Brugian Filiarisis disease.
Synthesis, Characterisation and Catalytic Activity of Sol-Gel Derived Silica-Mineral Acids
Authors: Nordin Nor Asikin Mohamad , Hamzah Noraini , Adnan Nadia Farhana , Wan Isahak Wan Nor Roslam , Yusof Mohd Zahid M. , Salimon Jumat , Yarmo Mohd Ambar
Published: December 2012

Sol-gel silica-supported mineral acids (namely sol-gel perchloric acid (slg HClO4), sulfuric acid (slg H2SO4) and phosphoric acid (slg H3PO4), prepared by incorporating mineral acids molecules into silica via sol-gel technique, were used as an efficient heterogeneous catalyst for the direct addition reaction of oleic acid (OA) to form estolides compound. The reactions were carried out under vacuum (2 mBar) for 10 hours at 70°C under solvent-less conditions. Liquid chromatography-mass spectrometry time of flight (LC-MS ToF) of reaction products results showed chromatographic peaks for the presence of two new estolide compounds, oleic-oleic monoestolide acid (m/z 563.51, as [M--), and oleic-oleic diestolide acid (m/z 845.77 [M--). The HClO sol-gel catalyst turned out to be the best catalyst, achieving a final conversion of 76.4% with 83.4% selectivity to oleic-oleic monoestolide acid (OOM) and 16.6% selectivity to oleic-oleic diestolide acid (OOD). The activity and selectivity of the mineral acid sol-gel catalysts have been investigated and compared with homogeneous HClO4. The samples were characterised by XRD, TPD-NH3 and XPS.
Formation of Titanium Silicon Carbide (Ti3SiC2) via Modified Self-Propagating High Temperature Synthesis (SHS) System through Arc Melting
Authors: Mazuki Norlailatullaili , Mohamed Julie Juliewatty , Ahmad Zainal Arifin
Published: December 2012

Ti3SiC2 compound was synthesized from the starting powder mixtures of 3Ti/1.2Si/2C/xAl (x=0, 0.1, 0.2, 0.3) by using arc melting method. The effect of Al on the Ti3SiC2 formation was studied. X-ray diffraction and scanning electron microscopy were used to characterize the synthesized materials. It was found that the addition of Al increased the purity of Ti3SiC2. When x=0.2, Ti3SiC2 content in the final product reached 67% after being ball milled for 24 hours. However, excessive Al reduced the content of Ti3SiC2. In addition, the density of the final product decreased with increasing of Al content. It was revealed that addition of Al in the starting powders can increase the final product purity.
Preliminary Preparation and Characterization Studies of Cellulose from Merbau (Intsia bijuga)
Authors: Mamat Razali Nur Amira , Abdul Aziz Fauziah , Rahman Saadah Abdul
Published: December 2012

Hardwood is wood from angiosperm trees. The characteristic of hardwood include flowers, endosperm within seeds and the production of fruits that contain the seeds. This paper aims to discuss the preparation and characterization of cellulose obtained from hardwood. The hardwood Merbau (Intsia bijuga) was chosen as raw material in this study. Alkaline treatment and delignification methods were used for the preparation of cellulose. Acid hydrolysis was employed to produce cellulose nanocrystal (CNC). The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The final product, from both trated and untreated samples were then compared.
X-Ray Spectrometry Study on Historical Decorative Glasses in Thailand: Lanna-Style Glass
Authors: Dararutana Pisutti , Won-In Krit , Intarasiri Sawet , Kamwanna Teerasak , Tancharakorn Somchai , Sirikulrat Narin , Hauzenberger Christoph A.
Published: December 2012

t was known that historical objects were highly heterogeneous. Due to the complex nature of materials and objects, extremely sensitive, spatially resolved, multi-elemental and versatile analytical instruments were needed. The techniques employed should be as a noninvasive as possible and able to give complementary information from macroscopic to nanometer scales. In this work, X-ray based spectroscopy including energy dispersive X-ray fluorescence spectroscopy (EDS), Proton-induced X-ray emission spectroscopy (PIXE), and micro-beam X-ray fluorescence spectroscopy (µ-XRF) were used to analyze chemical composition of the Lanna-style glass. Microstructure was also studied. It can be concluded that these techniques in combination are powerful for the investigation of heterogeneous glassy materials.
X-Ray Diffraction Studies of CdxZn1-xS Thin Films Prepared by Spray Pyrolysis Technique
Authors: Raviprakash Y. , Bangera Kasturi V. , Shivakumar G.K.
Published: December 2012

Thin films of CdxZn(1-x)S (0 x 1) were deposited on glass substrates by the chemical spray pyrolysis technique using a less used combination of chemicals. The variation of structural properties of these films in relation with composition was studied in detail. The entire study was made for a wide range of compositions of CdxZn (1-x) S thin films (x=0 to 1 in steps of 0.1). XRD studies reveal that all the films are polycrystalline with hexagonal (wurtzite) structure of which reflection peaks associated with (100), (002) and (110) planes were clearly identified for all the films and inclusion of cadmium into the structure of ZnS improved the crystallinity of the films. The value of lattice constants a and c was found to vary with composition from 0.382 to 0.415 nm and 0.625 to 0.675 nm respectively.
Synthesis and Gas Sensing Properties of SnO2 Nanostructures by Thermal Evaporation
Authors: Wan Mustapha Wan Normiza , Abdul Hamid S.A. Rezan Sheikh , Hutagalung Sabar Derita , Hieu Nguyen Van , Mohamed Khairudin , You Chan Kok
Published: December 2012

Tin oxide nanostructures (NS) were grown on silicon substrates by thermal evaporation method with three different parameters. These parameters were temperatures (650 °C, 750 °C and 850 °C), nickel catalyst concentrations (0, 5 and 10 milimoles) and tin powder source to substrate distances (2 cm, 4 cm and 6 cm). The parameters were found to affect the size and morphology of the synthesized nanostructures. Formation of nanospheres (NSs), nanoneedles (NNs) and nanowires (NWs) of tin oxide were observed by Scanning Electron Microscope (SEM) at different synthesis conditions. Synthesis temperature was found to have most pronounced effect on the size and morphology of the nanostructures. Catalyst concentration has affected the porosity and growth of the nanostructures. The distance between source and substrate affected the nanostructures predominately on distribution and particle size. Energy dispersion X-ray (EDX) analysis confirms the presence of tin and oxygen in all nanostructures at all synthesis conditions. X-ray diffraction (XRD) proves the formation of tin oxide phase in all samples. Significant formation of tin oxide nanowires was observed at 850 °C. Gas sensing properties of SnO2 nanowires (NW) toward ethanol (C2H5OH) gas at 450°C with different volume concentration was measured. It was found SnO2 NW had good sensing properties for C2H5OH at 100 ppm compared to measurements made at 25-50 ppm.
Preparation and Characterization of Biphasic Calcium Phosphate Coatings on 316L Stainless Steel Fabricated by Electrophoretic Deposition
Authors: Abudalazez Asam M.A. , Kasim Shah Rizal , Ariffin Azlan B. , Ahmad Zainal Arifin
Published: December 2012

Biphasic calcium phosphate (BCP) ceramic is a synthetic biomaterial exhibiting a chemical composition similar to that of tooth mineral. Therefore, it is viably used in coating metallic implants manufactured from metals and alloys, such as titanium and stainless steel. In the present study, electrophoretic deposition (EPD) has been attempted for depositing BCP coatings on 316L Stainless Steel substrate followed by vacuum sintering at 800 °C for 1 h. The surface morphology, thickness, compositions and microstructure of the BCP coated 316L SS was investigated by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and the bond strength of the coating was measured.
Preparations and Characterization of Sago Starch Dispersion and Modification
Authors: Yahya Siti Rohana , Azura A. Rashid , Azahari Baharin
Published: December 2012

Sago starch was mechanically treated with a stirring ball mill using anchoid as dispersing agent. Sago starch chemical modification was obtained from grafting copolymerization with polybutylacrylate (PBA) to reduce hydrophilic properties. The mechanical dispersed and chemical modified sago starches were studied through scanning electron microscopy (SEM), fourier transform infrared spectrometry (FTIR), and x-ray diffraction (XRD) analysis.
Computational Studies of Electronic Structures and Hyperfine Interactions of Muonium in Tetraphenylgermane
Authors: Toh Pek Lan , Sulaiman Shukri , Mohamed-Ibrahim Mohamed Ismail
Published: December 2012

The equilibrium structure of muoniatedtetraphenylgermane (GePh4Mu) was studied using the first principle Density Functional Theory (DFT) method. Three muonium (Mu) trapping sites were considered, namely ortho, meta, and para positions on one of the phenyl rings. Geometry optimization procedure was utilized to determine the local energy minimum for all the systems. The total energies corresponding to Mu at the three positions are very similar to each other. For the meta case, the corresponding energy is higher than the other two sites by only about 0.03 eV. The hyperfine parameters of Mu were also calculated. The Mu isotropic hyperfine coupling constants were found to be 441.85 MHz, 449.80 MHz, and 439.01 MHz for the ortho, meta, and para cases, respectively. The anisotropic value was calculated to be very small.
Role of NbC Grain Growth Inhibitor on Microstructure and Hardness of WC-Stainless Steel Hard Metals
Authors: Trung Tran Bao , Hussain Zuhailawati , Ahmad Zainal Arifin , Ishihara Keiichi N.
Published: December 2012

In this work, 10 wt.% stainless steel (AISI304, FeCrNi) was used as a binder in WC-based hardmetal. Graphite powder (2 wt.%) was added in the mixture to avoid the formation of η-phase ((MW)6C) during sintering. NbC with 1, 1.5, 2 and 5 wt.% was used as WC grain growth inhibitor. The sintering process was done in a vacuum furnace at 1300°C for 1h. The results showed that there was no formation of η-phase or free graphite after sintering indicating the suitability of added graphite. Increasing the NbC contents resulted in decreasing of WC grains. 2 wt.% NbC was considered to be the optimal content for fine microstructure and uniform WC grain distribution. The highest hardness was achieved at 2 wt.% NbC with HV30 of 1660 kg/mm2. However, higher amount of added NbC (5 wt.%) caused the existence of coarse (Nb,W)C grains which decreasing the hardness.
Oxidative Degradation Monitoring of Natural Rubber Using S K-Edge X-Ray Absorption near-Edge Spectroscopy (XANES)
Authors: Taweepreda Wirach , Limphirat Wanwisa , Songsiriritthigul Prayoon
Published: December 2012

In this work, we present the results of sulfur crosslinking and degradation in natural rubber (NR) studied by X-ray absorption near-edge structure spectroscopy (XANES). Sulfur K-edge XANES spectra has been collected and analyzed to provide the geometry and electronic environment of sulfur crosslinks during vulcanization and degradation processes by ozone aging. We found that reversion took place before the onset of oxidative process at the sulfur bridge. Parallel to the oxidative process, the production of cyclic sulfanes took places. This physico-chemical properties which were calculated from S K-edge XANES spectra were correlated with the mechanical of NR films by varying accelerator type. The accelerator zinc diethyldithiocarbamate (ZDEC) gave highest film strength when compared with other accelerators: N-cyclohexylbenzothiazole sulfenamide (CBS), 2,2' dibenzothiazyl disulfide (MBTS), and tetramethylthiuram disulfide (TMTD).
Structural and Surface Studies of Undoped Porous GaN Grown on Sapphire
Authors: Ainorkhilah Mahmood , Zainuriah Hassan , Yusof Yushamdan , Yam Fong Kwong , Chuah Lee Siang , Naser Mahmoud Ahmed
Published: December 2012

Owing to its great potential in optoelectronic devices, structural and surface properties of porous GaN prepared by UV electrochemical etching has been investigated. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and high resolution X-ray diffraction (HR-XRD) phi-scan and rocking curves measurements revealed the nature of the pore morphology and nanostructures. SEM micrograph indicated that the shapes of pores for porous sample are nearly hexagonal. The AFM measurements revealed that the surface roughness increased in the porous sample. X-ray diffraction phi-scan showed that porous GaN sample maintained the epitaxial feature.
Quantitative Energy Dispersive X-Ray Flourescence Analysis of Low Alloy Steel by Regression and Modified Fundamental Parameter Techniques
Authors: Meor Sulaiman Meor Yusoff , Muslimin Masliana , Wilfred Paulus
Published: December 2012

EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, analyses of wide concentration ranges, and fast analysis with no sample preparation. The paper relates a comparative quantitative analysis using regression and modified Fundamental Parameter Technique FPT methods in the determination of minor elements present in low alloy steel. Regression was developed by plotting calibration graphs using low alloy reference standards while the modified FPT method involves incorporation of pure metal spectrum to the existing equation to improve on the accuracy of the analysis. Discrepancy tests carried out for the two methods showed that the error ranges were 0.3-6.5% and 1.2-7.9% for regression and modified FPT analyses, respectively. This makes the FPT method more acceptable for quantitative analysis of elements present in low alloy steel.
Influence of Substrate’s Alignment Strategy to the Growth of ZnO Nano-Petals via Solution-Immersion Method
Authors: Ab Aziz Azlinda , Khusaimi Zuraida , Rusop Mohamad
Published: December 2012

Zinc oxide (ZnO) nanostructures were successfully grown on gold-seeded Si substrate prepared by a solution-immersion method using a novel mixture of an aqueous solution of Zinc nitrate hexahydrate (Zn (NO3)2.6H2O) with a non-toxic, odourless urea (CH4N2O) as a stabilizer. Structural and optical properties of resultant ZnO thin films were investigated by X-Ray Diffraction, FESEM and Photoluminescence Spectroscopy (PL). Clusters of ZnO micro-flower with serrated broad petals with the thickness of petals approximately 60 nm were interestingly formed on the film with horizontal manner of alignment during immersion process. The smallest grain size (29 nm) along (100) orientation was achieve with the alignment of substrate tilt towards 60°. The petals structure has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.
Preparation of Co0.5Zn0.5Fe2O4 and Co0.5Mn0.5Fe2O4 Nanoferrites by Co-Precipitation Method
Authors: Javidan Abdollah , Hosseini Mir Hassan , Shaifi S.L.
Published: December 2012

Nanoparticles of Cobalt-zinc ferrite (Co0.5Zn0.5Fe2O4) and Cobalt-manganese ferrite (Co0.5Mn0.5Fe2O4) have been synthesized at room temperature by co-precipitation method with and without calcination process. Starting materials for preparation of nanooxides were Co (NO3)2.6H2O, ZnCl2, Fe (NO3)3.9H2O and Mn (NO3)2.4H2O. These salats were mixed in stoichiometric amounts and precipitated with sodium hydroxide. Synthesised materials are confirmed by XRD and SEM analysis. The FTIR spectra of nanooxides have been analyzed in the frequency range of 400-4000cm-1.
Identification of Mixed-Layer Mineral of Cambodian Clays and their Phase Changes upon Firing
Authors: Ngun Bun Kim , Mohamad Hasmaliza , Okada Kiyoshi , Bone Phat , Ahmad Zainal Arifin
Published: December 2012

Representative of clay deposits from central Cambodia were analyzed in terms of their mineral phases, mineralogical composition and phase changes after firing by qualitative and quantitative XRD analysis. To examine the phase changes, the samples were prepared and fired from 950 to 1200 °C. Results show that Cambodian clays contained quartz, illite, kaolinite, and chlorite-vermiculite mixed-layer as dominant mineral phases and the minor phases of albite and calcite also appeared in the samples. The rational analysis shows that chlorite-vermiculite was the main mineral in all Cambodian clays. After the samples were preceded upon firing, new phases of mullite, hematite and crystobalite were appeared above 1050 °C.
Effect of Microstructural Evolution on the Properties of Friction Stir Processed Al 6061 Alloy under Different Cooling Conditions
Authors: Arora Harpreet S. , Singh H. , Dhindaw Brij Kumar , Grewal Harpreet S.
Published: December 2012

In the current investigation, friction stir processing (FSP) of aluminium alloy 6061 alloy was carried out under different cooling conditions to determine its influence on the microstructure evolution and properties of the investigated alloy. It was found that the type and distribution of the strengthening precipitates in the friction stir processed Al 6061 alloy significantly depend on the FSP parameters and working temperatures during FSP. The properties of friction stir processed alloy were evaluated using micro-hardness and bulk hardness tests. It was observed that 6061 alloy friction stir processed under rapid cooling conditions exhibited enhanced hardness which was found to vary between nearly 12 to 33 % as compared to the alloy processed under ambient cooling conditions.
Properties of Mortar Containing Rice Husk Ash at Different Temperature and Exposed to Aggressive Environment
Authors: Jaya Ramadhansyah Putra , Nor Mohd Al Amin Muhamad , Ahmad Zainal Arifin , Amin Zakaria Mohd
Published: December 2012

The properties of mortar containing rice husk ash at varying temperatures were studied. Three rice husk ash samples were prepared at different temperatures and with various colors, i.e., 600°C (pink), 800°C (grey), and 1000°C (white), all were used for this study. Ordinary Portland cement (OPC), a well known universal binder, was partially replaced with rice husk ash at 10, 15, 20, and 30% by weight of binder. The water to binder ratio (W/B) of the mortar was kept constant at 0.45. The mortars were subjected to seawater or saturated Ca (OH)2 solution. The controlled and exposed mortars were characterized using X-ray diffraction, FTIR spectroscopy and compressive strength test. The results show that the amount of silica present in RHA are varied with burning temperature and colors, approximately in the range of 95 to 97%. White RHA produced higher compressive strength both in seawater and Ca (OH)2 solution. Finally, white RHA with 15% replacement was most suitable to be used as additive in OPC, and showed good potential for use in seawater applications and alkaline environment.
Self-Healing Materials as New Biologically Inspired Materials
Authors: Ghezzo Fabrizia , Miao Xi Geng
Published: December 2012

Lightweight, high strength fibre-reinforced polymeric composites are leading materials in many advanced applications including biomedical components. These materials offer the feasibility to incorporate multi functionalities due to their internal architecture, heterogeneity of materials and the flexibility of combining them using currently available fabrication methods. In spite of the excellent properties of these materials, their failure is still a questionable and not well predicted event. Delamination, debonding and micro-cracks are only some of the failure mechanisms that affect the matrices of polymer based composites. More complex cases exist with the combination of multiple failure mechanisms. In such cases a self-repairing mechanism that can be auto-triggered in the matrix material once the crack has been formed, would be very beneficial for all the applications of these materials, reducing maintenance costs and increasing their safety and reliability. Self-healing materials have been studied for more than a decade by now, with the specific objective of reducing the risks and costs of cracking and damage in a wide range of materials. Different approaches have been taken to create such materials, depending on the kind of material that needs to be repaired. The most popular methods developed for polymers and polymer reinforced composites are considered in this review. These methods include materials with micro-capsules containing a healing agent, and composites with matrices that can self-heal the cracks by repairing the broken molecular links upon external heating. While the first approach to healing has been widely used and studied in the past decade, in this review we focus on the second approach since less is reported in the literature and more difficult is the development of the materials based on such a method.
Rib Design for Kirchhoff's Plate Inspired by Venation Configuration
Authors: Xue Kai , Li Yong Xin , Wang Wei Yuan
Published: December 2012

A new reinforcement distribution design method inspired by venation configuration is discussed in the paper. Learned from dicotyledonous venation, venation growing algorithm is proposed, minimization of strain energy and shear stress determine growth direction of the mainveins and subveins respectively. Vectorial equilibrium equation is used to calculate vein widths and adjust the orientation of vein cells slightly. Sensitivity number is used to measure the change in strain energy and shear stress when a vein cell grows, necessary equations are derived for bending Kirchhoffs plate. Several examples are design for venation-like rib distribution. The resultant rib layout by VGA is applicable and effective.
Characterization and Degradation Behaviour of Anodized Magnesium-Hydroxyapatite Metal Matrix Composites
Authors: Gill P. , Munroe N. , McGoron A.
Published: December 2012

Recently, magnesium (Mg) alloys have inspired a significant amount of attention from researchers all over the world for implant applications due to their light weight, mechanical integrity and degradation behaviour. The major concerns with Mg implants are its rapid and non-uniform degradation, which can increase the risk of leached ions and can cause premature failure. In this study, Mg based alloys/metal matrix composites (MgZnCa/HA) were mechanically and electrochemically (anodized) surface treated. In-vitro corrosion tests revealed that the addition of hydroxyapatite (HA) and anodizing, stabilizes the corrosion process and lowers hydrogen evolution. Evidence of reduced degradation was provided by the presence of a relatively smooth surface morphology after corrosion. Furthermore, exposure of leached ions on osteoblast cells indicated good cytocompatibility.
Reliability Studies on Timber Data from Nigerian Grown Iroko Tree (Chlorophora excelsa) as Bridge Beam Material
Authors: Aguwa J.I. , Sadiku S.
Published: December 2012

This paper provides the results of structural reliability analysis carried out on the data of Nigerian grown Iroko tree (Chlorophora excelsa), to ascertain its structural performance as timber bridge beams. Five pieces of 50mm x 75mm x 3600mm of Nigerian grown Iroko hardwood were bought, seasoned naturally and 200 pieces of samples were prepared for determination of their strength properties, (which include bending strength parallel to grain, tensile strength parallel to grain, compressive strength parallel to grain, compressive strength perpendicular to grain and shear strength parallel to grain) at a moisture content of 18%, in accordance with the British Standard BS 373 of 1957. Statistical analysis was carried out using the strength properties for determination of mean, standard deviation, coefficient of variations, confidence limits and Chi-Square goodness of fits. Structural analysis and design of a timber bridge beam using the determined data from the Nigerian grown Iroko timber, in accordance with BS 5268 were carried out under the Ultimate Limit State of loading (ULSL). Reliability analysis was carried out to ascertain its level of safety using First-Order Reliability Method (FORM). Sensitivity analysis was also carried out by varying the depth of beam, imposed live load, breadth of the beam, unit weight of the Iroko timber, span of the beam as well as the end bearing length. The result revealed that the Nigerian grown Iroko timber is a satisfactory structural material for timber bridge beams at depth of 400mm, breadth of 150mm and span of 5000mm under the ULSL. The probabilities of failure of the Nigerian grown Iroko timber bridge beam in bending, shear, compression and deflection are respectively, under the specified conditions of loading.
An Overview of Strut-and-Tie Model and its Common Challenges
Authors: Panjehpour Mohammad , Ali Abang Abdullah Abang , Mohammed Parvez Anwar , Aznieta Farah Nora , Voo Yen Lei
Published: December 2012

B-Regions are parts of the structure in which Bernoulli's principle of straight-line strain is used. D-Regions are parts of the structure with a complicated variation in strain. In essence, D-Regions contain the parts of structure which are near to the concentrated forces or steep changes in geometry which are so-called geometrical discontinuities or static discontinuities. Strut-and-Tie Model (STM) is one of the best models to analyse the D-regions. Nevertheless, according to the existing literature, there are still some challenges about STM which are addressed in this paper. STM and its details are investigated to show its common challenges presents some recommendations to overcome these challenges. According to this review, the major challenges in STM are related to the strut effectiveness factor, static uncertainties of STM, strain compatibility, and anchorage requirements in STM. The scope of this research is confined to the two dimensional STM.
Effect of the Solid Concentration in the Suspension on Electrophoretic Deposition (EPD) Coating Parameters
Authors: Abudalazez Asam M.A. , Kasim Shah Rizal , Ariffin Azlan B. , Ahmad Zainal Arifin
Published: December 2012

In this study, electrophoretic deposition (EPD) method was used for biphasic calcium phosphate (BCP) coating on 316L stainless steel substrates, using ethanol as a dispersive medium. Deposition was achieved on the cathode at 30 V in 30 seconds at room temperature in variable concentrations (0.5, 0.8, 1, 1.25, 1.5g of BCP powder). After deposition, the coated substrates were sintered at 800 °C for 1 hour. The phase purity and structure of the synthesized powders were checked by X-ray diffraction (XRD). The morphology, structure and phase composition of the coatings were investigated by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results show that deposition weight and thickness increased with increasing concentration. Furthermore, increases in cracks and changes in morphology on coating surfaces as concentration increased at the constant applied voltage during electrophoretic deposition were observed.
The Financial Health of Construction Companies in Qatar: A Case Study
Authors: Varghese Binu , Menacere Karim
Published: December 2012

This paper aims to assess the impact of financial factors which have a direct bearing on the success or failure of the construction companies. This paper is part of the main study which aims to identify key areas of strategic issues for construction companies in Qatar by using 6S strategic management framework. This research adopts a combination of primary and secondary data using a questionnaire survey involving 115 companies holding 99 per cent of the market share in Qatar. In this case study, a total of 17 financial ratios were employed as performance measurement tools. Interpreting these ratios, typical median (industry average) and typical range were used to compare a companys average ratios. The analyses reveal that most of the construction companies do not have sufficient financial resources, lack of monitoring system for the cash flow, and project costs. Without effective strategic management practices, construction companies are putting their self-up to failure. In addition to comparing the financial health of construction sector, this study aims to fill in the gap by creating basic benchmarks for 17 ratios applicable to construction sector in Qatar.
Nematic Liquid Crystals (NLC) Alignment by the Oriented Nanopatterns of some Polymers Functionalized with Monochlorotriazinyl-β-Cyclodextrin
Authors: Grigoriu Ana Maria , Luca Constantin , Grigoriu Aurelia , Racu Cristina , Hitruc Gabriela , Stoica Bogdan , Grigoriu George Ervant
Published: December 2012

This paper presents the practical strategies of obtaining the oriented nanostructured surfaces of some polymers functionalized with monochlorotriazinyl-β-cyclodextrin (MCT-β-CD) by two techniques: uniaxial rubbing or linearly polarized UV light (LPUVL) irradiation. We have chosen for the present study polymers and copolymers with exotic behavior with hydroxyl groups allowing the grafting of the reactive product monochlorotriazinyl-β-cyclodextrin or whose pyridinic nuclei can be complexated with MCT-β-CD. The obtained oriented nanostructures align colourless nematic liquid crystals (NLC) or NLC coloured with a dichroic dye. The orientation of NLC has been studied by means of polarized light FT-IR spectroscopy (IR dichroism) and polarized light UV-VIS spectroscopy (VIS dichroism). The initial polymers as well as the chemically modified products have an exotic behavior with regard to the ability of orientating the NLC. The polymers functionalized with MCT-β-CD orientate the NLC perpendicularly to the rubbing direction (or, for photopolymers, perpendicularly to the electrical vector of LPUVL).
Surface Modification of Polydimethylsiloxane Using Low Pressure Chemical Vapour Deposition of Poly-Chloro-p-Xylene
Authors: Poleni Paul Emile , Pereira-Rodrigues Nazare , Guimard Denis , Arakawa Yasuhiko , Sakai Yasuyuki , Fujii Teruo
Published: December 2012

The capability to understand and modulate accurately the self-assembly of the extracellular matrix (ECM) components still one of the major fundamental objectives in the field of liver tissue engineering. In the present study, we put in evidence the suitability of poly-chloro-p-xylene (Parylene-C, ParC) for modulating the self-assembly of ECM (type-I collagen) microenvironment and cellular topography of human hepatocarcinoma (HepG2) and Human umbilical vascular endothelial (HUVEC) cells while coated on a polydimethylsiloxane (PDMS) substratum. Our findings demonstrated that the wettability of PDMS and ParC/PDMS were identical, while ParC/PDMS was significantly rougher than PDMS before and after collagen coating. However, the roughness and the wettability of ParC/PDMS were comparable to those of polystyrene (PS), a substratum commonly used for in vitro biological-related investigations. Type-I collagen adsorbed on ParC/PDMS and PS exhibited a dense network of microstructures around ~1 nm high and ~30-50 nm wide, whereas collagen adsorbed on PDMS had a low surface density of elongated fibrils that were ~2 nm thick and ~200 nm wide. This disparity in ECM microarchitecture leaded to distinct culture topographies of HepG2 cells (3D and 2D for PDMS and ParC/PDMS, respectively) and viability of HUVEC (2D viable HUVEC cells and non attached dead cells on ParC/PDMS and PDMS, respectively). To conclude, the observed changes in cell morphology and viability between ParC/PDMS and PDMS alone were directly related to the nature of the material which may impact the supramolecular organization of adsorbed ECM. We strongly believe that Low Pressure Chemical Vapour deposition (LPCVD) of ParC will offer promising insights into how microscale ECM modifications directly impact cell morphology and activity, leading to the development of advanced micro/nanosized tissue-engineered ParC/PDMS patterns with applications for liver tissue engineering.