bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simple Method to Prepare Indium Oxide Nanoparticles on Si (110)
Authors: Amirhoseiny Maryam , Zainuriah Hassan , Ng Sha Shiong
Published: December 2012

Nanocrystalline indium oxide (In2O3) thin film was synthesized by thermal evaporation of indium on unheated Si (110) substrates, followed by wet oxidation process. XRD analyses showed the deposited In2O3 film is of high quality and have cubic structure. The Scherrer structural analysis revealed that the In2O3 film grown on Si (110) orientation has nanocrystalline structure with crystallite size of 2.53 nm. Photoluminescence (PL) spectrum showed a strong and broad emission at 574.9 nm with two shoulders at 547 nm and 604 nm which related to oxygen vacancies. Finally, the band gap of nanocrystalline In2O3 as determined from the PL spectrum was 2.15± 0.15eV.
Microstructure Evolution of Sn-3.5Ag-1.0Cu-0.5Ni/Cu System Lead Free Solder under Long Term Thermal Aging
Authors: Ab Ghani Noor Asikin , Yahya Iziana , Mohd Salleh Mohd Arif Anuar , Shamsuddin Saidatulakmar , Ahmad Zainal Arifin , Mayappan Ramani
Published: December 2012

Due to environmental concerns, lead-free solders were introduced in replacing the lead-based solders in microelectronics devices technology. Although there are many lead-free solder available, the Sn-Ag-Cu solder was considered the best choice. But the solder has its draw backs in terms of melting temperature and intermetallic formations. In this study, the effect of 0.5wt% Ni addition on the microstructure of the Sn-3.5Ag-1.0Cu solder was investigated. The solder was synthesized via powder metallurgy route which includes blending, compacting and sintering. The solders were characterized for its densities and melting temperatures. SEM was used to observe the microstructure of intermetallic phases. The solders were melted on copper substrate at 250°C for one minute and aged at 150°C from 0 to 400 hours. The phases formed were studied under SEM. The SEM results showed the presence of Cu6Sn5, Cu3Sn, Ag3Sn and (Cu,Ni)6Sn5 intermetallics.
Morphology and Intermetallics Study of (Sn-8Zn-3Bi)-1Ag Solder under Liquid-State Aging
Authors: Jasli Nor Aishah , Abd Hamid Hamidi , Mayappan Ramani
Published: December 2012

This study investigated the effect of Ag addition on the morphology and growth rate of Cu5Zn8, Cu6Sn5 and Cu3Sn intermetallics in the Sn-8Zn-3Bi solder. The solder was prepared by mixing 1wt% of Ag into 99wt% of Sn-8Zn-3Bi solder. The intermetallics were formed by liquid-state aging, whereby the solders were reacted on Cu substrate above the melting temperature of the solder. The reflow was done at 250°C and 270°C at various soldering times. A scanning electron microscope (SEM) was used to observe the morphology of the intermetallic phase and energy dispersive X-ray (EDX) was used to identify the elemental composition. The Sn-8Zn-3Bi solder reacting with Cu substrate formed a single Cu5Zn8 intermetallic layer with a flat structure. On the other hand, the reaction between (Sn-8Zn-3Bi)-1Ag solder and Cu substrate produces Cu6Sn5 intermetallic. This Cu6Sn5 intermetallic has a scallop structure. As the soldering time increases, a second layer, identified as Cu3Sn starts to grow. The thickness of the intermetallics increases with aging temperatures and time. The addition of Ag into the Sn-8Zn-3Bi solder has significantly suppressed the formation of Cu5Zn8 intermetallic and promoted the growth of Cu6Sn5 intermetallic.
Determination of Crystallite Size in Synthetic and Natural Hydroxyapatite: A Comparison between XRD and TEM Results
Authors: Rahavi Soheila , Monshi Ahmad , Emadi Rahmatollah , Doostmohammadi Ali , Akbarian Hamed
Published: December 2012

The study reported here focuses on the crystallite size of synthetic hydroxyapatite (HAp) obtained using sol-gel method and natural HAp obtained by processing the natural bone. Human and camel bones were used for obtaining natural HAp. HAp particles were produced, characterized and compared for their crystallite size. The average crystallite size of the samples was derived from the X-ray Diffraction (XRD) data using the Scherrer formula and a new method called modified scherrer equation that was came by developing the Scherrer formula. The results showed the crystallite size of HAp gained from different sources were different. The crystallite size of synthetic, human and camel bone-derived HAp, were approximately 18, 23 and 29 nanometer, respectively. These values were less than those obtained from TEM images. It seems that calculated crystallite size using XRD data and Scherrer equations is less than the real size. This important finding must be taken into consideration in applying Scherrer equations.
Preparation of Cellulose Microfibrils from Banana (Musa acuminata) Pseudo-Stem Waste
Authors: Azraaie Noriean Binti , Abdul Aziz Fauziah , Shahidan Radiman
Published: December 2012

Cellulose microfibril from banana pseudo-stem fiber waste has been isolated and characterised. Isolation of microfibril cellulose from raw fibers was achieved using alkaline treatment and bleaching. The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Characterizations of treated and untreated samples were compared. XRD studies shows that the treated cellulose prepared by alkaline and bleaching treatment was more crystalline than the untreated banana fiber. Surface morphological studies using FESEM shows there was a reduction in fiber diameter during the chemical treatment.
Synthesis and Growth Mechanism of Catalyst-Free ZnO Nanowires Using Chemical Vapour Deposition
Authors: Hamzah Nur Atiqah Binti , Pung Swee Yong , Sreekantan Srimala , Aziz Siti Nor Qurratu Aini Binti Abd
Published: December 2012

Zinc oxides nanowires (ZnO NWs) were successfully synthesized on bare silicon substrates using Chemical vapour deposition (CVD) method without foreign catalyst. The ZnO NWs had good crystal quality as they exhibited a strong UV emission (373 nm) corresponding to the free exciton emission and a weak green arising from defect-related emission in PL measurement. Measurement of low temperature photoluminescence spectra show a peak of free exciton and defect bound excitons. The growth of these catalyst-free ZnO NWs was governed by Vapour-Solid (VS) mechanism.
Studies of Cell Growth on TiO2 Nanotubes
Authors: Ahmad Barudin Nur Hidayati , Sreekantan Srimala , Thong Ong Ming , Lay Lam Kit
Published: December 2012

The in vitro cell response was investigated on flat Ti surface vs nanostructured TiO2 nanotube surface. The titanium dioxide nanotube layers were prepared by electrochemical anodization of Ti in ethylene glycol, 5 wt% NH4F and 1ml H2O2. The nanotube layered structure and morphology were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The diameter and the length of the nanotubes are found to increase with anodization voltage. Hs27 and breast cancer cell line MCF-7 were used for cell interaction studies. Different surfaces of titanium show variation in term of growth and viability of cells. Different cell type also show different cellular responses to these surfaces. Titanium nanotube with tube diameter 90 nm promoted normal cell adherence and spreading but killed the cancer cells. The detail of the observation is discussed thoroughly in this paper.
Production of Biodiesel from Non-Edible Jatropha curcas Oil via Transesterification Using Nd2O3-La2O3 Catalyst
Authors: Rabiah Nizah M.F. , Taufiq-Yap Y.H. , Hussein Mohd Zobir
Published: December 2012

Biodiesel is viewed as the most promising alternative fuel to replace petroleum-based diesel since it is derived from renewable sources such as animal fats, vegetable oil and grease. Out of various vegetable oil resources for biodiesel production, Jatropha curcas oil (JCO) is a viable choice for biodiesel because it is non-edible and can be grown easily in a harsh environment. In this study, Nd2O3-La2O3 catalyst was prepared for transesterification of JCO with methanol, in order to evaluate its potential as a heterogeneous catalyst for biodiesel production. Under suitable transesterification condition at 210 °C with catalyst amount of 3 wt.%, methanol/oil molar ratio of 45 and reaction time for 4 h, the conversion of JCO to fatty acid methyl ester (FAME) achieved was more than 93% over Nd2O3-La2O3 catalyst.
Compressive and Wear Resistance of Alumina Reinforced Fe-Cr Matrix Composites
Authors: Shamsuddin Saidatulakmar , Jamaludin Shamsul Baharin , Hussain Zuhailawati , Ahmad Zainal Arifin
Published: December 2012

Fe-Cr matrix composite reinforced with alumina with mean powder sizes of 13, 23, 24 and 64 μm was successfully obtained through powder metallurgy method. The powder mixture were blended at a rotating speed of 250 rpm for thirty minutes and uni-axially pressed at a pressure of 750 MPa. Samples identified as J13, J23, J24 and J64 according to alumina particles size were sintered in a vacuum furnace under 10-2 Torr at a temperature of 1100°C for two hours with 10°C/minutes heating rate. The peaks of XRD patterns have been identified as belonging to the phases of Fe, Cr and alumina. The EDX analysis confirms the existence of Fe, Cr, Al and O. Reinforcing the Fe-Cr matrix with alumina particles bigger than 13 µm deteriorated the microstructure and mechanical properties of the composites. The wear coefficient for sample reinforced with 13 µm alumina particles is 2.46 × 10-11 with compressive strength of 278 MPa. Meanwhile for sample reinforced with 64 µm alumina particles its wear coefficient is 5.09 × 10-11 and compressive strength is 81 MPa. It is found that reinforcing smaller alumina particles sizes to Fe-Cr matrix resulted in better wear and strength properties of the composites.
Crystallization of TiO2 Nanotubes Arrays Grown by Anodization of Ti in Organic Electrolyte
Authors: Ismail Syahriza , Lockman Zainovia , Ahmad Zainal Arifin
Published: December 2012

The TiO2 anodized in organic electrolyte using 85% glycerol is used to investigate the crystalization of TiO2 nanotubes annealed in air. The anatase start to form at 300°C and rutile appear when the temperature about 600 °C. The phase transformation is dependent on the annealing time and temperature. The anatase can be form at low temperatures when the annealing time is prolonged. The morphology of the annealed TiO2 nanotubes changes as the function of the annealing temperature and the mechanism for the phase transformation of anatase to rutile is discussed.
Single Step Combustion Synthesis for the Preparation of Bismuth Titanate Ceramics for Potential Applications
Authors: Azlan Umar Al-Amani , Sreekantan Srimala , Mohd Noor Ahmad Fauzi , Razak Khairunisak Abdul
Published: December 2012

Bismuth titanate was systematically prepared by a single step combustion synthesis. Based on TG-DTA, the corresponding phase was completely obtained below 300°C, resulting in highly exothermic peak at 236°C. The formation of a single crystalline structure of Bi-layered with different degree of crystallinity was strongly affected by hydrolysis temperature. Goodness-of-fit indicator, S for entire samples was in the range of 1.55 1.94, which is acceptable for Rietveld refinement analysis. All Raman peaks became more intense and sharp with higher hydrolysis temperature, suggesting that the strong interactions between Ti-O bonding in BIT structure. The presence of peaks at 838 and 628 cm-1 in the IR spectrum can be ascribed to the stretching vibrations of Bi-O and Ti-O, respectively. Besides, the obtained powders are very fine with minimal grain growth, resulting in agglomerated powders.
Synthesis and Characterization of Ba0.3Sr0.7ZrO3 Ceramic Thick Films Prepared by Sol-Gel Technique
Authors: Wan Ali Wan Fahmin Faiz , Othman Mohamad Ariff , Rejab Nik Akmar , Abdullah Mohd Zaid , Marzuki Arjuna , Hutagalung Sabar Derita , Mohamed Julie Juliewatty , Ain Mohd Fadzil , Abdullah Norazharuddin Shah , Ahmad Zainal Arifin
Published: December 2012

This manuscript is explained and discussed the properties of ceramic thick films, [Ba0.3Sr0.7ZrO3, BSZ (0.7)] synthesized through sol-gel route. The gel decomposition was studied by thermogravinometry analysis (TGA). From thermal analysis, it had shown that BSZ (0.7) phase started formed at 800 °C and above. The crystal structure of this composite film studied exhibited highly polycrystalline materials by X-ray diffraction analysis. From high magnification observation of field emission scanning electron microscopy (FESEM), grain boundaries of BSZ (0.7) films are clearly defined meanwhile grains displayed are in flaky shape. The average diameters of the grains measured were 94.6 nm. However, grains boundaries of BSZ (0.0) films, are unclear and grains slightly look dendritic structure. Electrical characterizations of the films are carried out with impedance analyzer at 4 - 12 GHz respectively. Both of electrical permittivity and loss tangent observed are dependable with microstructural and structural of the films.
Mesoporous Silica Sol-Gel as Catalyst for the Synthesis of Alkylpolyglucosides
Authors: Amin Izazi Azzahidah , Yarmo Mohd Ambar , Nik Yusoff Nik Idris , Yusoff Mohd Zahid , Ayatillah Alifee
Published: December 2012

The synthesis of alkylpolyglucosides involves condensation of decanol with dextrose in the presence of mesoporous silica sol-gel as a catalyst. In this study, mesoporous silica was produced using sol-gel technique by converting tetraethyl orthosilicate (TEOS) into silica. The mesoporous silica was characterized using BET surface area measurement and X-ray Photoelectron Spectroscopy surface analysis. The specific BET surface area was 794m2/g. From the XPS analysis, the Si2p binding energy is 103.7 eV while the O1s binding energy is 532.8eV indicating the formation of Si-O-Si bond which attributed to SiO2. Mesoporous silica has been found efficient to be solid catalyst for synthesis alkylpolyglucosides and easy to be separated. The reaction was carried out 8 hours at 110°C-120°C under vacuum condition. The mass determination of alkylpoluglucosides has been achieved by ESI LC-MS/MS (ToF) positive-mode giving a mass peak at m/z = 343.21 corresponding to [M++ of alkylmonoglucoside peak at retention time 11.0 min.
Electrical and Optical Characterization of Mg Doping in GaN
Authors: Azimah E. , Zainal Norzaini , Zainuriah Hassan , Abu Bakar Ahmad Shuhaimi , Bahrin Azlan
Published: December 2012

Apossible evidence of Mg related emission in Mg doped GaN material is observed inoptical measurement, even without thermal annealing. Meanwhile, the electrical properties of the sample improve when Ni/Au contact layer was annealed up to 400°C, but degrade at further temperature. We propose that such behavior isrelated to degradation of surface morphology of metal contact at higher temperature.
Preliminary Evaluation of Mukah Clay Deposits
Authors: Seli Hazman , Bujang Japri , Ahmad Zainal Arifin
Published: December 2012

Mukah clay deposits are characterized and evaluated for their potential as industrial raw materials through chemical, mineralogical and fired body (900 to 1250o C) physical properties determinations. Results show that the main oxides in the samples are SiO2 and Al2O3, whereas the other oxides present only in small quantity. Kaolinite and quartz present as dominant mineral phases and the minor phases of muscovite, nacrite, illite also appeared in the samples. From the results of the fired properties, the significant development of densification of ceramic behaviour can be noticed at the firing temperature above 1000°C. Mukah clay demonstrated that it is most suitable to be used as raw materials for making pottery, general refractory, structural ceramics, wall and floor tiles.
Fabrication of Nanoporous Aluminum Oxide via a Two-Step Anodisation Process
Authors: Saidin Nur Ubaidah , Ying Kok Kuan , Ng Inn Khuan , Ilias Suhaila Hani
Published: December 2012

In this study, we report the fabrication of nanoporous aluminum oxide film from high purity aluminium foil via a two-step anodisation process controlled by a constant direct current potential ranging from 40 60 V from a DC power supply. The anodisation process was conducted at 20˚C in an electrochemical cell with the Al foil acting as anode, Pt as cathode and an acidic bath as electrolyte. Porous aluminium oxide films of pore diameters ranging between 30 90 nm were successfully fabricated. The morphologies and phase compositions of the anodized porous alumina films were investigated using scanning electron microscopy (SEM) and x-ray diffraction (XRD) for characterizations.
Fundamental Characterisation of Dredged Marine Sediments from Kuala Perlis Jetty by XRF, XRD and FTIR
Authors: Ramli Norhashimah , Haji Jumali Mohammad Hafizuddin , Wan Salim Wan Safizah
Published: December 2012

Dredging along Kuala Perlis Jetty results in huge amount of marine sediments which has thrown considerable challenge for disposal. This research was conducted to characterize dredged marine sediment which was collected at Kuala Perlis Jetty as potential raw material for brick production. Three different characterizations were performed namely XRF, XRD and FTIR. XRF analysis showed the presence of SiO2 and Al2O3 as major quantities. Low concentration of heavy metals namely As, Cr, Cu, Pb, Ni and Zn presence in the sediment comply the US EPA guideline for brick production. XRD analysis indicated the presence of quartz as primary mineral while kaolinite and illite also present as secondary and ternary phases. FTIR analysis identified various form of minerals presence in the samples which strongly supported XRD results.
Properties of Aluminium Thin Films on Polyimide Plastics as Back Contacts in Thin Film Silicon Solar Cells
Authors: Pakhuruddin Mohd Zamir , Ibrahim Kamarulazizi , Abdul Aziz Azlan
Published: December 2012

Aluminium (Al) thin films on polyimide (PI) plastic substrates prepared via thermal evaporation technique and annealed in nitrogen (N2) ambient at different temperatures (250 - 400°C, for 30 minutes) have been investigated. Structural properties of the as-evaporated film have been studied by high resolution X-ray diffraction (HR-XRD). The result illustrates crystalline nature of the Al thin film with a dominant Al (111) peak at 2θ = 38.4°. Atomic force microscope (AFM) shows increased surface roughness root mean square (RMS) with increased annealing temperature (with roughness of 11.96 nm at 400°C). Sheet resistance drops with increased temperature and records the lowest reading (64 mΩ/) at 400°C. Besides, increased annealing temperature also results in reduced surface reflectance (with minimum reflectance of 73% reflectance in the visible region at 400°C). The effects of the resulting Al back contact properties towards thin film silicon (Si) solar cells on PI substrates were subsequently discussed.
Dehydration Studies of Biomass Resources for Activated Carbon Production Using BET and XRD Techniques
Authors: Wan Isahak Wan Nor Roslam , Hamzah Noraini , Nordin Nor Asikin Mohd , Mohamed Hisham Mohamed Wahab , Yarmo Mohd Ambar
Published: December 2012

Activated carbon is produced from high cellulose containing biomass such as filter paper (FP), bamboo waste and palm empty fruit bunches (EFB) by dehydrating agent, concentrated sulfuric acid (H2SO4). At room temperature, treatment of H2SO4 is removed all the water molecules in the biomass and leaving only porous carbon without emitting any gaseous by-products. After activation by carbon dioxide (CO2), Brunauer-Emmett-Teller (BET) and X-ray Diffractometer (XRD) analysis showed the bamboo activated carbon (BAC) has good properties with higher surface area (862.76 m2/g), micropore area (463.62 m2/g) and some crystalline (graphite) phase formation. Acid treatment of biomass has shown high carbon content for FP (85.30%), bamboo (77.72%) and EFB (76.55%), and yield obtained was 47.85 wt.% (FP), 62.4 wt.% (bamboo) and 55.4 wt.% (EFB) by using dehydration method.
Characterisation of Phases and Lattice Parameter in Eutectic and Hypoeutectic Al-Si-Mg-Ce Cast Alloy
Authors: Anasyida A.S. , Hussain Zuhailawati , Daud Abdul Razak , Ghazali M.J.
Published: December 2012

The purpose of this work is to understand the phases formation and lattice parameter changes with addition 0.6 to 2.7 wt.% in Al-Si-Mg-Ce cast alloy. Al-Si-Mg-Ce eutectic and hypoeutectic cast alloy were prepared by conventional casting technique. The alloys were investigated by using optical microscope, Scanning electron microscope (SEM) and X-Ray diffractometry (XRD). The addition of Ce resulted in precipitation of Al4Ce in eutectic cast alloy and CeMg2Si2 in hypoeutectic cast alloy. The lattice parameter of Al increases with increase in Ce content wheareas lattice parameter of Si phase decreases as the Ce content increases.
Characteristics of Airborne Pm2.5 and Pm2.5-10 in the Urban Environment of Kuala Lumpur
Authors: Sara Y.Y. , Rashid M. , Chuah T.G. , Suhaimi M. , Mohamed N.N.
Published: December 2012

Gravimetric and elemental analyses were conducted at a site in Kuala Lumpur from 2008 to 2010, representing the local air quality of urban and traffic. Eighteen elements were detected by ED-XRF and was further analysed for enrichment factor and correlation study. About 19.7% elements were identified and detected in PM10, including 8.2% and 11.5% in fine and coarse fractions, respectively. Al was found predominant in coarse fraction. However its composition in PM2.5 was highly enriched pointed to some anthropogenic emission source. In fine particulates, the total mass was mostly dominated by Al, K, Mg and S. Those elements, probably from biomass burning accounted for more than 90% of total elemental detected in PM2.5.
Crystal Structure Optimization and Semi-Empirical Quantum Chemical Calculations of N-(3,4-Dichlorophenyl)-3-Oxo-Butanamide
Authors: Jotani Mukesh M.
Published: December 2012

The crystal structure of N-(3,4-Dichlorophenyl)-3-oxobutanamide (I) is optimized by semi-empirical methods using MOPAC2009 program. The optimized geometries from both Austin Model 1 (AM1) and Parametrization Model 6 (PM6) describe the conformational discrepancy and crystal packing. The energy minimized structures from both the models are in good agreement with X-ray crystal data. The intramolecular charge transfer interactions are studied from the molecular orbital calculations. The parametric molecular electrostatic potential (PMEP) calculated by AM1 semi-empirical method shows the involvement of oxygen and chlorine atoms in the crystal packing interactions. The aromaticity of phenyl ring in the structure is determined using HOMED calculations.
XRD Analysis and Tensile Properties of Attapulgite Clay Filled Polyvinyl Alcohol/Corn Starch Blend Films
Authors: Suki Fairus Mazlia Mat , Azahari Nur Azleen , Othman Nadras , Hanafi Ismail
Published: December 2012

Polyvinyl alcohol (PVOH) and corn starch (CS) blends were prepared with various amounts of attapulgite (AT) clay to form a series of PVOH/CS/AT blend films by using a solution casting method. The effect of AT on the XRD pattern and tensile properties of the composites were investigated. It was found that addition of AT in PVOH/CS blend has changed the crystallinity index of the blend films and thus influenced the tensile properties. PVOH/CS/AT1 blend films showed the highest crystallinity index and proved by the value of tensile strength and tensile modulus. The lowest crystallinity index is shown by the PVOH/CS/AT5 blend films.
ZnO Varistor Defective Gd and Pr Ions
Authors: El-Hofy M. , El-Taabl A. , Abdel Aziz A.M. , Elkhatib M.
Published: December 2012

To the best of our knowledge the difference in the magnetic properties of ions like Gd (7.94 μB) and Pr (3.58 μB) on the electrical properties of ZnO-varistor have not been studied. To clarify this effect, the binary systems, ZnO-Gd2O3, ZnO-Pr6O11and the ternary system ZnO-Gd2O3-Pr6O11were studied. The ceramics were prepared according to the chemical formula; (100-X) mol% ZnO - (X) mol% Y, where X = 0.5, 1, 2, 3.5, 5, 6, 7.5, 9 and 15, Y is Gd2O3, Pr6O11or Gd2O3 +Pr6O11. The samples have been sintered at 1200°C, 1250°C, 1300°C, 1350°C and 1400°C for 1 hr. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDAX), (JxE), (CxV) and Electron Spin Resonance (ESR) have been studied and discussed. Utilizing J-E characteristics, the non-linearity coefficient (α), leakage current (Lg) and breakdown electric field (Eo) have been determined. In the present study, the effect of the magnetic properties on the non-linearity parameters was not clear and the non-linearity characteristics mainly depend upon the microstructure of the system. The ternary system (94%ZnO-4%Pr6O11- 2%Gd2O3) is superior to the binary systems, and can readily serve as a high-voltage varistor.
Injecting CO2 and Pumping Out Saline Formation Water Simultaneously to Control Pressure Build-Up while Storing CO2 in Deep Saline Aquifers
Authors: Kabera Telesphore , Li Yi Lian
Published: December 2012

Production of saline formation water from the storage formation in sufficient amounts helps to control the pressure increase during CO2 storage in saline aquifers. In this paper, we present an engineering design to control the pressure build-up during CO2 storage in deep saline aquifers and we propose that the extracted saline formation water can be processed at the industrial level in order to produce commercial salt. We investigated the effects on various aquifer properties of pressure increases. Several design options for the injection operations are investigated: injection of CO2 without saline formation water production, injection of CO2 with one production well and, finally, injection of CO2 with one left side and one right side production wells. We showed that an increase in saline formation water production rate leads to pressure build-up decreases, when the production rate was tripled (from 61.42kg/s to 184.26kg/s); the maximum pressure was decreased by about 15bar. About a half of base case temperature (89°C to 45°C) increased the maximum pressure by about 35bar. The pore compressibility which is a key parameter defining the pressure response to CO2 injection has also been investigated whereby an increase in pore compressibility leads to decreases in pressure build-up. Simulation results showed that the introduction of two wells (left side and right side of the production well) increases more or less the horizontal migration of the CO2.
Physico-Mechanical Properties of Sintered Iron-Silica Sand Nanoparticle Composites: A Preliminary Study
Authors: Ahmad Tahir , Mamat Othman , Ahmad Rafiq
Published: December 2012

The present study aims to develop silica sand nanoparticles using the ball-milling process and to utilize these nanoparticles as reinforcement for iron-based metal matrix composites. Iron-based metal-matrix composites with 5, 10, 15 and 20wt.% of the processed silica sand nanoparticles were developed using powder metallurgy technique and sintered at 900°C, 1000°C and 1100°C. The results showed that the addition of silica sand nanoparticles to iron as reinforcement decreased the green density, albeit with an improvement in sintered densities. It was also observed that the increase in the sintering temperature results in an improvement of microstructure and microhardness of the composites. The maximum hardness of 168HV in iron-based composites was found with the addition of 20wt.% of silica sand nanoparticles at a 1100°C sintering temperature. It is proposed that the mechanism for the occurrence of this observed increment in microhardness is due to diffusion of silica sand nanoparticles into porous sites of the composites, resulting in the formation of FeSi phase.
Studying the Effect of Low α-Radiation Doses on CR-39 Polymers Using Positron Annihilation Lifetime and Mechanical Properties
Authors: Eissa M.F. , Hassan E.M. , Badawi Emad A.
Published: December 2012

Positron annihilation lifetime spectroscopy (PALS) is one of the unique tools for studying free-volume defects in solid media. The microhardness test offers a simple and nondestructive tool for investigating the mechanical behavior of polymer materials. Polyallyl diglycol carbonate (CR-39) track detectors have a variety of applications in science and technology. PALS measurements and microhardness tests were verified for CR-39 irradiated with different doses of alpha particles (0 - 69.20 mGy). The variations in free volume hole size and fractional free volume were obtained by using the PALS method. The small free volume hole sizes were found at doses 27.68 and 44.98 mGy. The microhardness test for the two doses yielded medium values.
Properties and Antimicrobial Activity of Nanosilver Deposited Cotton Fabric Coated with γ-Methacryloxypropyl Trimethoxysilane
Authors: Kurajica Stanislav , Očko T. , Mandić Vilko , Cigula Kurajica V. , Lozić I.
Published: December 2012

The simple and industrially adjustable process of silver nanoparticles deposition on cotton fabric followed by coating with γ-methacryloxypropyl trimethoxysilane (MPS), as well as the properties of obtained nanocomposite has been investigated. Silver nanoparticles were prepared through the reduction of silver nitrate with sodium borohydrate and deposited on cellulose fabric. In order to stabilize obtained nanostructured material and improve its properties, the fabric was treated by immersion in cross linkable MPS. The morphology of the finished fabrics was characterized by Scanning Electron Microscopy (SEM). It has been determined that process does not impair nanocharacter of silver particles and yield uniform distribution throughout the fabric surface. The concentration of Ag in the fabric samples was determined by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The average deposited amount of nanoparticles was found to be 63 ppm and 48 ppm for samples without and those with MPS, respectively. The character of obtained polysiloxane coating was examined using Fourier Transform Infrared (FTIR) spectroscopy. The presence of SiOSi bonds on the cellulose surface pointed out to self-condensation between silanol groups. Differential Thermal and Thermo-Gravimetric Analysis (DTA/TGA) revealed that MPS deposited on fabric provided modification of thermal properties. The change of the surface properties after the modification was ascertained by contact angle measurements. The antimicrobial activity of the antibacterial finish on the cotton fabric, expressed as bacterial reduction efficiency, has been determined. Bacterial reduction of at least 88.5% against both, Staphylococcus aureus and Escherichia coli, has been obtained.
Revisiting Shari’ah, democracy and human rights in Nigeria
Authors: Mbamalu Williams O.
Published: December 2012

This article argued that in a pluralistic and complex society such as Nigeria the invocation of Shari’ah (Islamic law) does not augur well for the survival of democracy. The traditional belief of every Muslim is that fundamentalism has been and must continue to be rooted in the concept of theocracy upon which the medieval institution of the Caliphate actually rested. Muslim political leaders challenge the agitation for a secular state in Nigeria as an inspiration by Christian theology based on Western European thought. This article argued that political and social progress in Nigeria is unrealistic without the separation of religion and politics. It was identified in this article that the separation of religion and politics does not go down well with Islamic eschatology and cosmology, because Islam’s main theological drive is toward an Islamic world empire. The solution offered in this article was that emphasis should be on ensuring that any legal framework or constitutional arrangement should be one that safeguards the interests of all citizens.’n Blik op Shari’ah, demokrasie en menseregte in Nigerië. Hierdie artikel argumenteer dat, in ’n pluralistiese en komplekse samelewing soos Nigerië, die aanroeping van Shari’ah (Islamitiese wet) niks goeds voorspel vir die oorlewing van die demokrasie is nie. Die radisionele geloof van elke Moslem is dat fundamentalisme in die konsep van teokrasie, wat sy oorsprong in die  Middeleeuse instelling van die Kalifaat het, gewortel is en so moet bly. Politieke Moslemleiers beskuldig die Christelike teologie (wat op die Wes-Europese gedagte gebaseer is) as die oorsaak van die onrus as gevolg van die poging om ‘n sekulere staat in Nigerie tot stand te bring. In hierdie artikel is is ook geargumenteer dat politieke en sosiale vooruitgang in Nigerië nie moontlik is sonder die skeiding van godsdiens en politiek nie. Daar is ook bevind dat die skeiding tussen godsdiens en politiek nie by die Islamitiese eskatologie en kosmologie inpas nie, omdat die Islam se belangrikse teologiese oogmerk  ‘n Islamitiese wêreldryk is. Die slotsom van die artikel is die beklemtoning van die feit dat enige wetlike raamwerk of grondwetlike samestellings daarop gerig moet wees om die belange van alle burgers te beskerm.
Avian bornavirus genotype 4 recovered from naturally infected psittacine birds with proventricular dilatation disease in South Africa
Authors: Last Robert D. , Weissenböck Herbert , Nedorost Nora , Shivaprasad H.L.
Published: December 2012

The occurrence of proventricular dilatation disease caused by avian bornavirus (ABV) in captive psittacine birds has long been suspected in South Africa. This report documents the first detection by polymerase chain reaction and gene sequence analyses of ABV from three clinical cases of proventricular dilatation disease (PDD) in captive bred blue and gold macaws (Araara rauna) resident in this country. Lymphoplasmacytic encephalitis, gastrointestinal myenteric gangioneuritis and leiomyositis were the most prominent histopathological changes and ABV genotype 4 was detected in tissues from all three birds. Immunohistochemical stains for ABV antigen revealed positive labelling of neurons and glial cells of the brain, myenteric ganglia and nerve fibres as well as smooth muscle cells of the gastrointestinal tract of all three birds. In one bird, positive labelling of the peripheral nerves was observed. The identical sequence of the analaysed genome fragment of all three samples, history that all of these birds had originated from the same breeding facility, and young age at presentation raise the question of possible vertical transmission.
Evaluation of Matrix-Assisted Laser Desorption/Ionization Mass spectrometry for second-Generation Lignin Analysis
Authors: Richel Aurore , Vanderghem Caroline , Simon Mathilde , Wathelet Bernard , Paquot Michel
Published: December 2012

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted herbaceous lignins. Optimization of analysis conditions, using a typical organic matrix, namely α-cyano-4-hydroxycinnamic acid (CHCA), in combination with α-cyclodextrin, allows efficient ionization of poorly soluble lignin materials and suppression of matrix-related ions background. Analysis of low-mass fragments ions ( m/z 100-600) in the positive ion mode offers a “fingerprint” of starting lignins that could be a fine strategy to qualitatively identify principal inter-unit linkages between phenylpropanoid units. The molecular weights of lignins are estimated using size exclusion chromatography and compared to MALDI-TOF-MS profiles. Miscanthus ( Miscanthus x giganteus) and Switchgrass ( Panicum Virgatum L.) lignins, recovered after a formic acid/acetic acid/water process or aqueous ammonia soaking, are selected as benchmarks for this study.
Biomass and Burning Characteristics of Sugar Pine Cones
Authors: Gabrielson Anton T. , Larson Andrew J. , Lutz James A. , Reardon James J.
Published: December 2012

We investigated the physical and burning characteristics of sugar pine (Pinus lambertianaDouglas) cones and their contribution to woody surface fuel loadings. Field sampling was conducted at the Yosemite Forest Dynamics Plot (YFDP), a 25.6 ha mapped study plot in Yosemite National Park, California, USA. We developed a classification system to describe sugar pine cones of different sizes and decay conditions, and examined differences among cone classes in biomass, bulk density, flame length, burning time, consumption, and relative contribution to surface fuel loads. Sugar pine cones comprised 601 kg ha−1of surface fuels. Mature cones comprised 54 % of cone biomass, and aborted juvenile cones accounted for 44 %. Cone biomass, diameter, and bulk density differed among cone condition classes, as did burning characteristics (one-way ANOVA,P< 0.001 in all cases). Flame lengths ranged from 5 cm to 94 cm for juvenile cones, and 71 cm to 150 cm for mature cones. Our results showed that the developmental stage at which sugar pine cones become surface fuels determines their potential contribution to surface fire behavior in Sierra Nevada mixed-conifer forests. Sugar pine cones burn with greater flame lengths and flame times than the cones of other North American fire-tolerant pine species studied to date, indicating that cones augment the surface fire regime of sugar pine forests, and likely do so to a greater degree than do cones of other pine species.
A probability of snow approach to removing cloud cover from MODIS Snow Cover Area products
Authors: López-Burgos V. , Gupta H. V. , Clark M.
Published: December 2012

Abstract. Satellite remote sensing can be used to investigate spatially distributed hydrological states and fluxes for use in modeling, assessment and management. However, in the visual wavelengths, cloud cover can often obscure significant portions of the images. This study develops a rule-based, multi-step method for removing clouds from MODIS Snow Cover Area (SCA) images. The methods used include a combining images from more than one satellite, time interpolation, spatial interpolation, and estimation of the probability of snow occurrence based on topographic information. Applied over the Upper Salt River Basin in Arizona, the method reduced the degree of cloud obscuration by 93.8% while maintaining a similar degree of image accuracy to that of the original images.
Quantification of genetically modified maize MON 810 in processed foods
Authors: Bergerová Eva , Godálová Zuzana , Siekel Peter
Published: December 2012

Maize MON 810 (Zea mays L.) represents the majority of genetically modified food crops. It is the only transgenic cultivar grown in the EU (European Union) countries and food products with its content higher than 0.9 % must be labelled. This study was aimed at impact of food processing (temperature, pH and pressure) on DNA degradation and quantification of the genetically modified maize MON 810. The transgenic DNA was quantified by the real-time polymerase chain reaction method. Processing as is high temperature (121 °C), elevated pressure (0.1 MPa) and low pH 2.25 fragmented DNA. A consequence of two order difference in the species specific gene content compared to the transgenic DNA content in plant materials used has led to false negative results in the quantification of transgenic DNA. The maize containing 4.2 % of the transgene after processing appeared to be as low as 3.0 % (100 °C) and 1.9 % (121 °C, 0.1 MPa). The 2.1 % amount of transgene dropped at 100 °C to 1.0 % and at 121 °C, 0.1 MPa to 0.6 %. Under such make up the DNA degradation of transgenic content showed up 2 or 3 time higher decrease a consequence of unequal gene presence. Such genes disparity is expressed as considerable decrease of transgenic content while the decrease of species specific gene content remains unnoticed. Based on our findings we conclude that high degree of processing might have led to false negative results of the transgenic constituent quantification. Determination of GMO content in processed foods may leads to incorrect statement and labelling in these cases could misleads consumers.
The cadmium intake of selected legumes in model conditions
Authors: Harangozo Ľuboš , Stanovič Radovan , Árvay Július , Trebichalský Pavol
Published: December 2012

The work is to evaluate the extent of risk transfer of heavy metals from soil burdensome to their different levels of consumption of selected parts of the crop. The goal to be achieved in conditions of simulated vegetation pot experiments. To implement the experiment, we used the agricultural soil of land site Výčapy - Opatovce. The experiments use two types of leguminous plants: Faba beans (Faba vulgaris M.), a variety MERLIN lentil dishes (Lens esculentum) variety NELKA. In one experimental tank was weighed 5 kg of soil mixed with 1 kg of silica sand, and the bottom of the container we put a small drainage layer of gravel. Within each container, we applied the calculated dose of the basic fertilizer, as well as various amounts of soluble salts of cadmium observed. Crops are harvested when fully ripe and the  wet mineralization of plant samples was determined by heavy metals AAS method for device VARIAN 240FS. Significant ratio of cadmium is in the aboveground biomass of the legumes. Lentils take into aboveground biomass much more cadmium than  faba beans. The cadmium content in the first two variants is significantly lower than in the next two in both crops. We may conclude that the faba beans, and lentils to accumulate an increased amount of cadmium in soil in a relatively large amount of seeds. Although it is clear that Faba bean received cadmium content was compared with more lentils. Due to the significant accumulation of Cd by plants lentils and excessive production of the aboveground biomass is potentially usable lens as fytoremediation crop recovery for metalic polluted soils.
Influence of lifetime exposure of sublethal doses of cadmium to selected parameters of carbohydrate metabolism
Authors: Lukačí­nová Agnesa , Nováková Jaroslava , Lovásová Eva , Cimboláková Iveta , Ništiar František
Published: December 2012

The aim of the study was to assess the effects of exposure to low doses of cadmium dissolved in drinking water (at a concentration 200 times higher than the maximum permissible dose) on selected parameters of carbohydrate metabolism in 20 Wistar rats. Animals were divided into two groups – control and experimental groups exposed to low doses of cadmium chloride in concentration 20 μM of drinking water. We studied the biochemical parameters, as glucose, hemoglobin, glycated hemoglobin, lactate dehydrogenase and amylase in blood of rats. Glucose, hemoglobin, glycated hemoglobin and amylase levels increased, lactate dehydrogenase was no changed of rats exposed to cadmium. Good indicators of chronic intoxication by cadmium are elevated levels of glucose, hemoglobin and mainly glycated hemoglobin in blood. The evaluation results should be taken into account not only the data at the end of the experiment but for the entire duration of trials (i.e., more time steps), which results largely make objective.
A Case of Purtscher Retinopathy Associated with Stent-Assisted Coil Embolization of a Middle Cerebral Artery Aneurysm
Authors: Yang Hyun Seung , Joe Soo Geun , Yoon Young Hee , Kim June-Gone
Published: December 2012

Purpose.

This article reports a case of Purtscher retinopathy following therapeutic coil embolization of a middle cerebral artery (MCA) aneurysm.

Methods.

Case report.

Results.

A 53-year-old woman with a history of stent-assisted coil embolization in her left MCA unruptured aneurysm presented with a visual disturbance about 3 hours after the procedure. Her left eye vision was 20/40. Fundus examination of the left eye showed an intraretinal hemorrhage and multiple whitish retinal lesions. The spectral-domain optical coherence tomography (OCT) examination showed focal thickness around the whitish lesions and a hemorrhage site. Three weeks later, the retinal whitish lesions decreased but new multiple intraretinal hemorrhages were found near the previous whitish lesions. Fluorescein angiography revealed the obstruction of an arteriole at the posterior pole. After 5 weeks, all lesions in the fundus photography and OCT were almost gone and her left visual acuity was 20/20.

Conclusions.

A thorough understanding of clinical findings and mechanism of this disorder, including the possibility of direct emboli during coil embolization rather than secondary emboli from the postoperative coil-thrombus complex formed in the aneurysm after the procedure, is therefore necessary to prevent unwanted ocular complications after coil embolization.
Modeling of Phase Separation Mechanism in Polycaprolactone/Dioxane Binary Systems
Authors: Larobina Domenico , Guarino Vincenzo , Ambrosio Luigi
Published: December 2012

Purpose

Unidirectional freezing followed by freeze-drying is a way to produce microcellular material from a polymer solution for biomedical application. As a distinctive feature of this type of process, bundles of channels are observed with an average diameter of hundreds of microns. Variations in porous morphology, particularly in porosity, density, and degree of regularity of spatial organization of pores, have been observed when polymer concentrations and quenching temperature are changed. To examine these issues in more detail the thermally induced phase separation of a polycaprolactone/dioxane solution was studied as a function of polymer concentration and quenching temperature in connection with the ultimate morphology of the micro-cellular material.

Methods

We prepared microcellular samples of polycaprolactone by freeze/freeze-drying technique. The microstructure of the material was observed by scanning electron microscopy. Moreover, a mathematical model for the prediction of the temperature profile and morphology was developed.

Results and Conclusions

A microstructural disorder region inside the samples was sometimes observed in connection with process parameters. The developed model is able to capture the formation of such a microstructural disorder region as a direct consequence of the slowing down of the solid-liquid interface. Predictions of the model as a function of freezing rate and concentration are in excellent agreement with experimental observation.
Polymeric Microstructures with Shape-Memory Properties for Biomedical Use Built by Stereolithography
Authors: Sharifi Shahriar , Blanquer Sebastien , Grijpma dirk W.
Published: December 2012

Purpose

The aim of this study was to design and build porous microstructures with shape memory behaviour using biodegradable poly(D,L-lactide-co-trimethylene carbonate) dimethacrylate macromers. These microstructures could be advantageous for tissue engineering and other advanced biomedical applications.

Methods

Porous structures with a gyroid pore network architecture showing average pore sizes of 930 μm and complete pore interconnectivity were prepared by stereolithography. Built structures were characterized by micro-computed tomography (μ-CT). Shape recovery and shape fixity of microstructures after 40% and 70% compression were evaluated.

Results

At 37 °C the flexible structures showed compression modulus values of 60 KPa and could be fully compressed. Thermal analysis showed that the built networks were amorphous with Tg values of 23 °C. After compression to 40 and 70%, shape fixity and shape recovery of the structures at respectively 0 °C and 37 °C was almost quantitative.

Conclusions

The well-defined pore network characteristics and the shape-memory properties of these structures allow their use as deployable tissue engineering scaffolds.