bluuebunny/crossref_metadata_2025 huggingface dataset:
The Compensation of Y Waveguide Temperature Drifts in FOG with the Thermal Resistor
Authors: Wang Ying Li , Ren Li Yong , Xu Jin Tao , Liang Jian , Kang Meng Hua , Ren Kai Li , Shi Nian Bao
Published: April 2014

The lithium niobate integrated optical phase modulator (Y waveguide) is the key device in the digital closed-loop fiber optic gyroscope. However, the half-wave voltage of the lithium niobate changes with the environment temperature, which produces the phase bias drift and ultimately decreases the accuracy of FOG. In this manuscript, the thermal resistor is introduced in the amplification part in the driving circuits of Y waveguide. Due to the characteristic of the thermal resistor, the magnitude of driving voltage on Y waveguide changed with temperature to compensate the electro-optic effects temperature drift of the lithium niobate. This method was proved to improve the performance of fiber optic gyroscopes conveniently in experiment.
CNTs Mixed into W and B by Ball-Milling Method and their Application in Delay Composition
Authors: Wang Si Yi , Ren Hui , Jiao Qing Jie , Han Bao Liang
Published: April 2014

With the progress in science and technology, the dynamic security, the reliability, the accuracy and the stability of delay composition in complicated condition attracts more and more attentions. Traditional delay composition can not meet our requirements of the reliability and security. Its the first time carbon nanotubes (CNTs) with high heat conductivity and high intensity are added into the system of Tungsten type delay composition and boron type delay composition. CNTs were mixed into W and B by ball-milling method. Particle size analysis and transmission electron microscopy (TEM) are utilized to analyse the size structure and dispersity of W/ CNTs and B/ CNTs. Optimum conditions of preparing W/CNTs and B/CNTs were found to apply to fuel agent of delay composition. In addition, burning rate and delay precision of the four delay charges (BaCrO4/W, BaCrO4/W/CNTs,BaCrO4/B and BaCrO4/B/CNTs delay compositions) were reseached. Results show that delay compositions added to CNTs had higher burning rate and better delay precision than original delay charges (burning rate of BaCrO4/W/CNTs was as much as 3-4 times higher than that of BaCrO4/W under the same constraints. Meanwhile, burning rate of BaCrO4/B/CNTs is 2 times higher than that of BaCrO4/B). Especially, the ignition reliability of charges added to CNTs were improved while charge density exceeds about 6000 Kg/m3. So the addition of certain amount of CNTs in the delay compositions can obviously increase the burning rate and the ignition reliability of delay compositions.
Application of Lift-Off Process in Fabricating Nanoimprint Stamp
Authors: Wang Zhi Hao , Liu Wen , Zuo Qiang
Published: April 2014

Lift-off process is a critical combined process in semiconductor manufacturing field. However, traditional methods of lift-off process can hardly be carried out in Ultraviolet Nanoimprint Lithography due to the poor solubility of ultraviolet imprint resist. In this paper, a modified lift-off process using a multi-layer transfer method has been introduced to solve this problem. More importantly, this method could bring an improved result even if the aspect ratio of hard stamp is small. By applying this method, we succeeded in fabricating pillar photonic crystal stamp using hole pattern mother stamp and using the newly defined stamp to fabricate nanopattern sapphire substrate. Depth of the nanopattern is 250nm and the profile of the pattern is pyramid type which is very suitable for subsequent epitaxy.
Comparative Studies on Enzymatic Activity of Porcine Pancreatic Lipase Immobilized onto Functionalized Rod-Like SBA-15 Mesoporous Materials with Aminopropyl and Glutaraldehyde
Authors: Li Yan Jing , Li Chang Jun , Wang Zhi Long , Zhou Guo Wei
Published: April 2014

Rod-like SBA-15 mesoporous materials were synthesized and modified using two-step process through aminopropyl and glutaraldehyde. Aminopropyl was first covalently bonded to silanol groups present on the surface of mesoporous silica. Successively, the reaction of aldehyde with aminopropyl was followed. Immobilizations of Porcine pancreatic lipase (PPL) onto functionalized SBA-15 (NH2-SBA-15-PPL and G-SBA-15-PPL) have been achieved. Relative activities and reusability of NH2-SBA-15-PPL and G-SBA-15-PPL for triacetin hydrolysis have been studied.
Preparation and Photocatalytic Activity of Fe3+-TiO2-CTAB Nanostructured Films
Authors: Yue Chun Xiao , Shen Jun , Ding Peng , Yao Lan Fang
Published: April 2014

Fe3+-TiO2-CTAB nanostructured films were prepared by self-assembly technique, using surfactant cetyltrimethyl ammonium bromide (CTAB). The properties of the samples were examined by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and UV-Vis spectrophotometry, respectively. The crystalline phase of the sample calcined at 450°C is mostly anatase-TiO2 (A) accompanied by a small amount of rutile-TiO2 (R). No significant characteristic peaks of iron oxide were detected in the XRD patterns, it suggested that Fe3+ ions incorporated into the TiO2 skeleton and composed the mesoporous structures with TiO2 uniformly. Fe3+-TiO2-CTAB nanofilms exhibited higher photocatalytic activity under the effect Fe3+ of and CTAB.
Synthesis and Hydrogen Absorption Capacity of Multilayered SnO2 Hollow Microspheres
Authors: Wang Zhi Yuan , Wang Feng Ping , Li Ming Yan , Iqbal M. Zubair , Javed Qurat Ul Ain , Lu Yan Zhen , Xu Mei , Li Quan Shui
Published: April 2014

Multilayered SnO2hollow microspheres (MHS-SnO2) have been successfully synthesized via a solvothermal method by using glycol-water as solvent. The morphology, composition and structure of the product have been characterized by field-emission scanning electron microscopy (FESEM) with an energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and X-ray diffraction (XRD). The FESEM, TEM and HRTEM images indicate that the as-prepared microspheres show multilayered structure and the wall of the hollow microspheres is composed of single crystalline nanoparticles. Study on hydrogen absorption characteristics of MHS-SnO2performed at 373 K shows a good absorption capacity of 0.85 wt.%.
Preparation and Properties of Chitosan Graft Copolymer Nanoparticles Using Potassium Diperiоdatоnickelate
Authors: Liu Zhan Jun , Zhao Ming Fei , Wu Zhen Gang , Han Gang
Published: April 2014

Nanoparticles comprising chitosan-graft-poly (methyl methacrylate) (CS-g-PMMA) copolymer were successfully synthesized in aqueous solution by using potassium diperiоdatоnickelate (Ni (IV)) as an initiator. The nanoparticles were characterized in terms of Fourier transform infrared (FTIR), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results indicated that chitosan was covalently linked to poly (methyl methacrylate) (PMMA) and the particles were uniform, spherical and well dispersed with narrow size distribution. Paclitaxel-loaded nanoparticles were prepared and in vitro release showed that these nanoparticles provided an initial burst release followed by a slowly sustained release for more than 16 days. Therefore, this process method would be used for synthesizing natural polymer graft copolymer nanoparticles with wide prospect.
Synthesis of Allyl-Functionalized Polymers via Selective Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization
Authors: Liu Zhan Jun , Zhao Ming Fei , Wu Zhen Gang , Han Gang
Published: April 2014

Allyl-functionalized copolymers with well-defined structure have been successfully prepared via selective reversible addition-fragmentation chain transfer (RAFT) copolymerization of styrene and allyl methacrylate possessing a higher reactive methacrylate and a lower reactive allyl. By employing a fast RAFT equilibrium, the polymerization for AMA completely occurred in methacrylate double bonds, whereas allyl double bonds remained intact and were introduced into the side-chains. GPC and 1H NMR analyses have confirmed the high chain-end functionality of the resultant copolymer.
Electrospinning Carboxymethyl Cellulose Lithium (CMC-Li) Nano Composite Material for High-Rate Lithium-Ion Battery
Authors: Qiu Lei , Shao Zi Qiang , Liu Ming Long , Liu Yan Hua
Published: April 2014

New cellulose derivative CMC-Li was synthesized, and nanometer fiber composite material was applied to lithium-ion battery and coated with AQ by electrospinning. Under the protection of inert gas, modified AQ/ carbon nanofibers (CNF) /Li nanometer composite material was obtained by carbonization in 280OC as lithium battery anode materials for the first time. The morphologies and structure performance of materials were characterized by using IR, SEM, CV and EIS, respectively. Specific capacity was increased to226.4 mAh.g-1after modification for the first discharge at the rate of 2C. Performance of cell with CMC-Li with the high degree of substitution (DS) was superior to that with low DS. Cellulose materials were applied to lithium battery to improve battery performance by electrospinning.
Influence of Surfactant on the Crystal Form and Photocatalytic Properties of Nano-TiO2
Authors: Guo Lan Ying , Li Ying , Zhou Hui , Li Fu Yun , Zhou Da Huan , Yang Li Zhen
Published: April 2014

The nano-TiO2 was prepared by adding surfactant chitosan and sodium dodecyl benzene sulfonate (DBS) under hydrothermal conditions. The influence of chitosan and DBS on the crystal form and photocatalytic properties of TiO2 was discussed. Chitosan acted as the chelant in the reaction, while DBS played the function of preventing aggregation of powder and increasing the degree of crystallization. The fixed calcination temperature was 500°C. The crystallite size could reach about 40.1nm upon the addition of 1g chitosan, and the catalytic efficiency was 51.89%. The crystallite size was about 45.8nm upon the addition of 1g DBS, and the catalytic efficiency was 48.13%. The nano-TiO2 had smaller particle size when chitosan was added under the same reaction conditions.
Removal of Benzene from Aqueous Solution Using Carbon Nanotube Synthesized from Fuel Oil Waste
Authors: Al-Khateeb Ismail , Mohammed Ahmed M. , Haider Adawiya J. , Al-Douri Y.
Published: April 2014

This investigation is dealing with adsorption of benzene compound from aqueous solution using a new carbon nanotube (CNT) synthesized from a fuel oil waste of power plants which identify by FE-SEM and TEM. It was found that a CNT has a very significant adsorption for benzene compared to that of non-activated carbon. The equilibrium adsorption data were analyzed using adsorption models of Langmuir, Freundlich and Temkin. The results showed that the model isotherms are fitting very well with the experimental data. Kinetic study was conducted and the results pointed out that a pseudo-first order model was represented the data. Values of the activation thermodynamic functions were calculated through equilibrium constants at different temperature. All values of Gibbs functions were negative with values of-1.6 and-13.0 kJmol-1 for non-active and CNT respectively, while values of enthalpy and entropy were about-33kJmol-1 and-65JK-1 mol-1 for CNT respectively. These results indicated that the adsorption process was feasible, spontaneous and exothermic.
Synthesis and Characterization of Zinc Oxide Nanostructures by Different Sonication Period
Authors: Sarip Nurulnadia , Norhidayah Che Ani , Kamaruddin Sharul Ashikin , Mahmud Farhanahani , Tawil Siti Nooraya Mohd , Sahdan Mohd Zainizan
Published: April 2014

Zinc oxide (ZnO) is a wide band gap semiconductor material (3.37 eV) with numerous present applications such as varistors, surface acoustic wave devices and future biomedical applications. ZnO nanorods were grown under specific growth condition by an inexpensive and simple, chemical bath deposition method on ZnO seeded glass substrates. Study of the ZnO nanorods over different precursors, i.e zinc acetate dehydrate and zinc nitrate hexahydrate, and sonication period ranging from 0 to 120 seconds by field emission scanning electron microscope (FESEM), including the nanorod size and the surface morphology, will be demonstrated in this paper. Characterization of the ZnO film using both X-ray diffraction (XRD) and UV-Vis spectroscopy will be established in determining the optimal composition along with the optical properties, respectively.
The Effects of Process Parameters on the Pyrolysis of Empty Fruit Bunch (EFB) Using a Fixed-Bed Reactor
Authors: Mohamed A.R. , Hamzah Zainab , Daud Mohamed Zulkali  Mohamed
Published: April 2014

Malaysia is well-known as one of the main producer and exporter of palm oil. With the high production of crude palm oil (CPO), huge amount of empty fruit bunch was generated as by-products. The abundant amount of EFB produced required careful waste management procedures. Pyrolysis is thermochemical decomposition of biomass in inert environment towards its conversion into bio-oil, bio-char and gas. In this study, the pyrolysis of empty fruit bunch (EFB) was conducted using a fixed bed reactor. The pertinent process parameters such as pyrolysis temperature, particle sizes and heating rates were investigated via the determination of the percentage product yields such as bio-oil, bio-char and gas. The first series of experiment was conducted to determine the effect of pyrolysis temperatures. The final pyrolysis temperature was varied at 300, 400, 500, 600 and 700 °C at constant heating rates and the nitrogen flowrates of 30 °C/min and 100 cm3/min respectively. It was determined that at pyrolysis temperature of 500 °C maximum bio-oil yield of 35.00 % was obtained with bio-char and gas yield of 26.98 and 38.02% respectively. In the second series of experiment, the effect of particle sizen was studied. The EFB particle was varied at <125, 125-250, 250-500, 500-710 and 710-1000 μm. The pyrolysis temperature was fixed at 500 °C with nitrogen flowrate of 100 cm3/min and heating rate of 30 °C/min. It was determined that using EFB particle size of 250-500 μm, the maximum bio-oil of 38.52% was achieved with bio-char and gas yields of 25.06 % and 36.42% respectively. In the third series of experiment to determine the effect of heating rates, the heating rates was varied at 10, 20, 30, 40, 50 and 60 °C/min towards the final pyrolysis temperature of 500 °C with constant nitrogen flowrates of 100 cm3/min. The results obtained showed that the highest amount of bio-oil of 40.81% was obtained when the heating rate of 20 °C/min was used. The bio-char and gas yield obtained were 24.69% and 34.50% respectively.
Reactive Ion Etching Parameter Effect on Aluminum Bond Pad Surface Morphology
Authors: Palianysamy Moganraj , Sauli Zaliman , Hashim Uda , Retnasamy Vithyacharan , Taniselass Steven , Ayub Ramzan Mat
Published: April 2014

Reactive Ion Etching (RIE) is an important process in fabrication of semiconductor devices. Design Of Experiment (DOE) has been used to study the effect of Reactive Ion Etch (RIE) towards surface morphology of aluminum bond pad. Important RIE factors involved in this experimental study are ratio of Tetrafluoromethane (CF4), Argon gas flow, BIAS, and ICP power. Different combinations of these factors produces different results of surface morphologies which was obtained using Atomic Force Microscopic (AFM). Produced results shows that overall surface roughness of the pad is affected by RIE and DOE offers a better way to optimize the desired outcome.
Characterizations of Hydroxyapatite - Saccharomyces cerevisiae Complex for Bioethanol Production
Authors: Anuar Adilah , Ahmad Salimi Midhat Nabil , Daud Mohamed Zulkali Mohamed , Yeoh Fei Yee
Published: April 2014

Immobilized cell reactor (ICR) has been used widely for bioethanol production. It has been shown to improve the performance of fermentation efficiency. The immobilization of S.cerevisiae was simply performed by enriched cells cultured media harvested at exponential growth phase. Hydroxyapatite (HAp) was found to be a suitable candidate as a solid support of surface adsorption by S.cerevisiae. The strong affinity binding of phosphate backbone of S.cerevisiae and calcium ion in HAp had been proven the effectiveness of HAp as immobiliser, thus the yield from the fermentation process has been increased. However, specific characteristics for HAp-yeast complex such as size, porosity (pore size and pore volume), surface morphology and total surface area are the important factors that were needed to control in order to avoid the detachment of the microorganisms from solid support. The characterizations performed were Mastersizer for complex size determination, Scanning Electron Microscopy (SEM) for surface morphology and Brunauer, Emmett and Teller analysis (BET) for specific surface area determination.
Electro Synthesised NiTe2 Thin Films with the Influence of Additives
Authors: Anand T. Joseph Sahaya , Zaidan Mohd
Published: April 2014

Solar cell is one of the promising alternative green energy sources that can provide free electricity when sunlight is converted. The absorbent materials and their synthesis methods are subject of interest mainly due to solar panel installation cost despite of free electricity generated. The well-known silicon solar cells made, either amorphous or polycrystalline are good in conversion efficiency up to 17%, but their high cost make the researchers to look for alternate materials. Semiconducting materials in thin film form such as InP, SnO2 and ZnO are being studied as the alternative materials, but are not commercialised due to their poor conversion efficiency. Another group of semiconductor compounds known as transition metal chalcogenides (TMC) have been developed to be used as the absorbent materials. Consisting of transition metals and chalcogenides (S, Se and Te), they show promising solar absorbent properties such as semiconducting band gap, well adhesion to substrate and good conversion with better cost-effective. There are many TMC compounds synthesised, including copper indium selenide (CIS), ZnTe2, CdSe etc. Nickel, one of the transition metals synthesised with chalcogenides are referred as nickel chalcogenides. There are many possible combinations of nickel chalcogenides such as NiS2, NiSe, NiSe2 and Ni3Se2. The combination of nickel and telluride are the fewest being observed due to the nature of tellurium that is poorly-adhesive onto the substrate. Therefore, NiTe2 thin film is being electro-synthesised onto the indium tin oxide (ITO) coated glass substrates and their properties are studied. The additives are being used to improve the adhesion between the film and substrate. Cyclic voltammetry experiments have been done prior to electrodeposition in order to get the electrodeposition potential range where the observable reduction range is between-0.9-(-1.1) V. The electrodeposition is carried out using the potentials in the reduction region, producing the well-adherent, well-distributed and dark-coloured thin films.
Structural Properties of Zn-PbI2 Nanostructures
Authors: Mohammed Safaa I. , Al-Douri Y.
Published: April 2014

The structural properties of Zn-doped and undoped lead iodide ( PbI2 ) nanostructures have been investigated. Zn-doped and undoped of ( PbI2 ) have been grown by chemical technique. Different doped and undoped PbI2 when prepared successfully by thermal evaporation technique an glass substrate at room temperature. Characterization and analysis using scanning electron microscopy (SEM) and X-ray diffraction (XRD) have indicated to the crystalline character. The particle size of Zn-PbI2 is larger than undoped PbI2.
Spin Coating Effect on Structural and Morphological Properties for CdS/Glass Nanostructures
Authors: Al-Douri Y.
Published: April 2014

CdS/glass nanostructures are prepared at 400 °C by sol-gel spin coating method without catalyst. These nanostructures have been characterized by analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM). The grin size, full width half maxima, miller indices, strain, dislocation density, lattice constant and interplaner distance are measured. The measured and calculated results showed a good agreement with other experimental and theoretical data.
Growth of Aligned ZnO Nanorods Grown on Polyethylene Naphthalate Substrates: Effect of the Growth Duration
Authors: Shabannia Reza , Haslan Abu Hassan
Published: April 2014

Aligned ZnO nanorods were synthesized on a polyethylene naphthalate (PEN) substrates using a chemical bath deposition method. The growth temperature and precursor concentration were 95 °C and 0.025 M, respectively. The effects of growth duration (2 h to 8 h) on the optical and structural properties of the obtained ZnO nanorods on seed layer ZnO/PEN substrate were then investigated using X-ray diffraction, field-emission scanning electron microscopy (FESEM), and photoluminescence (PL) spectroscopy at room temperature. The high intensity of (002) peak compared with (100) and (101) in the X-ray diffraction (XRD) pattern demonstrated that the ZnO nanorods grown for 6.5 h had more vertical higher crystal quality than the samples grown for other durations. The average diameter of ZnO nanorods grown on PEN substrates increased from 19 nm to 45 nm with increased growth duration from 2 h to 8 h, respectively.
Effect of Substrate Bias in Copper Sputtering Plasma Measured by Langmuir Probe
Authors: Low Jia Wei , Nayan Nafarizal , Sahdan Mohd Zainizan , Abd Kadir Mahamad , bin Ahmad Mohd Khairul , Yeon Md Shakaff Ali , Zakaria Ammar , Ahmad Saad Fathinul Syahir , Mohd Zain Ahmad Faizal
Published: April 2014

There are several techniques to deposit the metal oxide thin film such as electron beam evaporator, pulse laser deposition and reactive magnetron sputtering deposition. In this experiment, magnetron sputtering deposition techniques will be used to produce a copper oxide thin film due to its simplicity and repeatability performance. Recently, copper oxide thin film has been studied because of its low cost material, sensitivity to ambient condition and easiness to produce oxide thin film. It is one of the p-type semiconductor oxides materials that are suitable to be used as a gas sensing material. In order to increase the sensitivity and to optimize the properties of copper oxide thin film, it is essential to study on the plasma properties during the deposition of copper oxide. In current studies, Langmuir probe was used to investigate the effect of substrate bias towards the fabrication of copper oxide thin film at rf dissipation power of 400 W. The oxygen flow rate was fixed at 8sccm. The Langmuir probe tip was focus at roughly 2 cm above the substrate holder. The ion and electron current were collected from the plasma environment. Then the electron temperature, electron density, ion density, ion flux, Debye length and plasma potential at various substrate biases were evaluated from the current-voltage curve. The electron temperature at various oxygen flow rates was almost unchanged. The effect of substrate bias toward the electron temperature was also almost unseen, except that the electron temperature at-40 V bias voltage was slightly lower than others. In addition, the ion flux at the same plasma condition shows that the ion flux was higher at-40 V substrate bias voltage. The results suggest that the ion bombardment effect toward the deposited copper oxide thin film would be higher at low oxygen flow rate. Thus it will create a rough surface morphology or nanostructured copper oxide thin film. This is a potential ways to improve the sensitivity of copper oxide gas sensor.
Evaluation of Aerobic and Anaerobic Co-Digestion of Tetraselmis suecica and Oil Palm Empty Fruit Bunches by Response Surface Methodology
Authors: Ahmad Ashfaq , Shah Syed Muhammad Usman , Buang Azizul , Othman Mohd Fariduddin , Abdullah Mohd Azmuddin
Published: April 2014

This study investigated co-cultivation of Tetraselmis suecica microalgae with Oil Palm empty fruit bunch (OPEFB) for anaerobic biomethane production and Palm oil mill effluent (POME) treatment. The highest specific biogas production (0.1162 m3 kg-1 COD day-1) and biomethane yield (3900.8 mL CH4 L-1 POME day-1) was achieved with microalgae at 2 mL mL-1 POME, and OPEFB at 0.12 g mL-1 POME. Without co-digestion of microalgae, higher specific biogas production (0.1269 m3 kg-1 COD day-1) but lower biomethane yield (3641.8 mL CH4 L-1 POME day-1) were observed. Second order polynomial model fits the data well with less than 5% error. Higher removal efficiency (62-95%) of COD, BOD, TOC and TN were achieved by aerobic and anaerobic treatment of POME with microalgae than without microalgal treatment after 3 and 7 days of hydraulic retention time (HRT).
The Effect of Microalloying of Nickel, RRA Treatment on Microstructure and Mechanical Properties for High Strength Aluminum Alloy
Authors: Naeem Haider T. , Mohammad Kahtan S. , Ahmad Khairel R.
Published: April 2014

High strength aluminum alloys Al-Zn-Mg-Cu-(0.1) Ni produced by semi-direct chill casting process were homogenized at different conditions then conducted heat treatment process which comprised pre-aging at 120°C for 24 h, retrogression at 180°C for 30 min, and then re-aging at 120°C for 24 h. Microstructural studies showed that add Ni (0.1 wt %) to the alloy will be forming Ni-rich phases such as AlCuNi, AlNi, AlNiFe and AlMgNi which provide a dispersive strengthening affected in the solid-solution and the subsequent heat treatments. The results showed that by this three-step process of heat treatments, the mechanical properties of aluminum alloys Al-Zn-Mg-Cu-(0.1) Ni were substantially improved. The highest attain for the ultimate tensile strength and Vickers hardness for the alloy sample after applied the retrogression and reaging process is about 545 MPa and 237 HV respectively.
Catalytic Graphitization of Modified Phenolic Resin and its Nanoparticles Fillers Behavior towards High Temperature
Authors: Al-Falahi Hamid A.
Published: April 2014

This research is concerned with one of applications of partially graphitized process of carbon compounds. The target of the work is to investigate and study the activity of some additives as catalysts to promote graphitization of phenolic resins to use in preparing thermally stable nanoparticles fillers. Two types of additives have been dedicated as promoting factors. Ni (CH2COCH2COCH3)2.2NH3 is laboratory prepared. As for H3BO3, additive, it has been used ready-made. Two types of the modified resins are prepared through a chemical reaction and physical mixing between the resins and the inorganic compounds. Graphitization has successfully been conducted by implementing thermal treatment in a vacuum furnace at (1200-1400°C). This study exhibited the following results: FT-IR for modified resins showed the combination of boron-oxygen is attributed to the existence of the boron ion with the H3BO3, and the presence of ammonia molecules bonded to nickel ion in Ni (CH2COCH2COCH3)2.2NH3 allow for hydrogen bonding, confirmed by very broad stretching vibration (OH). On the other hand, the action of these catalysts is referred to their contribution in accelerating the graphitization process and to decrease the operational temperature to 1400°C as compared to that needed by amorphous carbon in order to be changed to graphite via traditional process about 3000°C. X-ray analysis showed the existence of graphite and turbostratic structures of the type (T&G-comp.), This means the degree of graphitization (D.O.G) and carbon yield of the prepared resins by chemical reaction is more than that produced by physical mixing. H3BO3 had slight effect on the carbons and less than from Ni (CH2COCH2COCH3)2.2NH3. Thermal analysis results (T, T.G, and T.G.A) of the modified resins should indicate that this property depends upon the type of the additive. Accordingly, it is possible to use these results in preparing modified resins and thermally stable fillers which can be used with composites. This requires investigating tests and experiments in this field. Key words: Catalytic graphitization, Degree of graphitization, Modified phenolic resins, Organometallic compounds, nanoparticles fillers.
Behavior of Ferro-Cement Slabs Modified by Polymer under Low Velocity Impact
Authors: Al-Hadithi Abdulkader Ismail , Aziz Khalil Ibrahim , Al-Dulaimi Mohammed Tarrad Nawar
Published: April 2014

Ferro-cement is a type of thin reinforced concrete made of cement-sand mortar mixture with closely spaced of relatively small diameter wire meshes. The main aim of this work was to study investigate the behavior of Ferro-cement slabs under impact loading. A total of 36 Ferro-cement slabs were constructed and tested under low velocity impact, The main parameter considered in the present investigation was number of wire mesh layers, content of (SBR) polymer and height of falling mass (falling velocity). A special testing rig was used to achieve the impact forces using a falling mass (1300 gm steel ball) dropped from (2.5, 1.2 and 0.83 m) height. (500 ×500×50 mm) slabs were used for each test. The polymer (SBR) was used as a ratio by weight of cement of 3%, 5% and 10%. The number of required blows for caused the first crack and final failure was recorded. The results exhibited that the number of blows which were required to make the first crack and failure, increased with increase of polymer content and number of wire mesh layers.
Structural and Electrical Properties of Titania Thin Films
Authors: Nadzirah Sharipah , Hashim Uda , Malihah N.
Published: April 2014

This research studies the properties of titanium dioxide (TiO2) nanoparticles synthesized by two different stabilizers via sol-gel method. Acetic and hydrochloric acids have been used as stabilizers to form two different TiO2 thin films. 100 μm gap of Al IDEs have been fabricated on each annealed TiO2 films. Finally the samples were physically and electrically characterized. Average crystallite sizes of the nanoparticles are 20 and 25 nm for acetic and hydrochloric acid respectively. The average current flow through the devices was extremely small which are around micro-to-nanoampere. It was found that the electrical conductivity increased significantly when particle sizes decreases.
Photochromic Behavior of Spiropyrans: The Effect of Substituent
Authors: Nadir Najiah , Wahid Zaharah , Zainuddin Mat Tamizi , Mohamed Islam Noor Zalikha
Published: April 2014

Spiropyrans are among the most promising organic photochromic dyes. However, spiropyrans are very sensitive dyes and there are many independent factors that can affect the performance of these dyes. The effect of substituent on the optical absorption spectra, fading kinetic, and also the dye stability of spiropyrans in diphenyl ether by UV irradiation has been investigated. The 6-nitro BIPS displayed greater absorbance intensity of 0.740% at 600nm compared to 8-ethoxy-6-nitro BIPS of 0.651% at 620nm. Furthermore, 6-nitro BIPS is less stable as it has higher rate constant of 0.1003s-1 and thus lower half-life time (50% decay of the photochromic effect) of 6.9s, in contrast to 8-ethoxy-6-nitro BIPS of 0.0594s-1 and 11.7s respectively.
Properties of Mortar Incorporating Ground Dune Sand as Cement Replacement Material
Authors: Alawad Omer Abdalla , Alhoziamy Abdulrahman , Jaafar Mohd Saleh , Al-Negheimish Abdulaziz , Abdul Aziz Farah Noor
Published: April 2014

Supplementary cementitious materials provide economic and environmental advantages in concrete industry. In this study, natural ground dune sand (GDS) was used as cement replacement material to fabricate mortar specimens. Ordinary Portland cement was replaced by GDS at five levels of replacement (0, 10, 20, 30, and 40 %) by weight. The cast mortar specimens were cured under normal and autoclave curing conditions. Compressive strength, drying shrinkage and resistance to sulfate attack were investigated. Results showed that the compressive strength under normal curing decreased as the level of replacement increased. However, under autoclave curing compressive strength increased as the content of GDS increased with 30% being the optimum replacement level. Autoclave curing decreased the drying shrinkage of plain and GDS blended mixtures by about 70% compared to control mixture cured under normal curing. Up to 270 days, no sulfate attack was observed on the GDS blended mixtures regardless of the replacement level. The use of GDS to reduce the Portland cement consumption can have a significant impact on the sustainability and economy of concrete construction.
Synthesis, Characterization and Activity Pattern of Carbon Nanofibres Based Cu-ZrO2 Catalyst in the Hydrogenation of Carbon Dioxide to Methanol
Authors: Din Israf Ud , Shaharun Maizatul Shima , Subbarao Duvvuri , Naeem A.
Published: April 2014

Carbon nanofibers based Cu-ZrO2 catalysts (Cu-ZrO2/CNF) were synthesized by deposition precipitation method. Carbon nanofibers of herringbone type were used as a catalyst support. Before using as catalyst support, carbon nanofibers were oxidized to (CNF-O) with 10 % (v/v) nitric acid solution. A series of catalyst with various copper loadings of 10, 15 and 20 wt% were synthesized. X-ray diffraction (XRD) study revealed that degree of crystallization of catalyst increase with increasing the concentration of copper content in the catalyst. BET studies showed higher surface area for low loading of copper. Temperature-Programmed Reduction (TPR) analyses concluded good interaction of catalyst particles with higher loading of copper. The performance of Cu-ZrO2/CNF catalysts in hydrogenation of CO2 reaction was studied in slurry-typed reactor at 443 K, 30 bar and H2: CO2 ratio of 3:1. The highest yield of methanol was achieved using the 20 wt% copper loading.
Thermal Degradation of Plastic Wastes (PP, LDPE) Using Metal Particles, Metal Oxides and Metal Nano Particles as a Catalyst
Authors: Ibraheem Ibraheem J. , Mandeel Tareg A. , Faisal A.D. , Al-Douri Y.
Published: April 2014

Two different vacuum thermal degradation processes of plastic wastes materials: Poly Propylene (PP) and Low Density Poly Ethylene (LDPE) were conducted with homemade thermal degradation setup. The two processes were used 1-bulk metal particles,2-metal oxides (Fe,Ni,Fe2O3,NiO) and 3-metal nanoparticles (Fe and Ni) as a catalysts supported on feldspar clay respectively. The experimental results for both processes shows the presence of different products like liquid, wax, gas, and carbon. Our characterization was focused on the liquid product. The produced liquid was characterized by Fourier transform infra-red (FTIR) and Gas chromatography (GC) The octane number, cetane number, flash point, fire point, aniline point and some physical properties were also measured. The results indicated that the process with metal nanoparticles catalyst produces liquid much better properties compared to the other materials results used metal particles catalyst.
Pressure Effect on the Electronic Properties of Cerium Monochalcogenides CeX (X=S, Se, Te) Using Modified Becke-Johnson Exchange Potential and LDA+U
Authors: Amrane Noureddine , Benkraouda Maamar
Published: April 2014

We present a systematic and comparative study of the electronic properties of CeX monochalcogenides, The density of state (DOS) and electronic band structure of CeX (X=S, Se, Te) have been calculated using the full-potential linearized augmented plane-wave (FP-LAPW) + local orbital (lo) method based on the density functional theory (DFT), which is implemented in WIEN2k code. The trends in the high pressure behavior of these systems are discussed. Four approximations for the exchange-correlation functional have been used, the GGA's of Perdew-Burke-Ernzherhof. (PBE08) , Engel-Vosko (EV93), a modified version of the exchange potential proposed by Becke and Johnson (MBJ), and LDA+U is used to calculate the band gaps at different pressures. All methods allow for a description of the Ce f electrons as either localized or delocalized, it is found that the underestimations of the bandgap by means of LDA-GGA and Engel-Vosko are considerably improved by using the modified Becke-Johnson (MBJ) potential for all compounds in the series, On the other hand, LDA+U, method gives good results for the lighter chalcogenides, but it fails to give good results for the heavier cerium monochalcogenides.
Study on Synthesis and Characterization of Cu-Ni Doped TiO2 by Sol-Gel Hydrothermal
Authors: Bashiri Robabeh , Mohamed Norani Muti , Kait Chong Fai , Sufian Suriati
Published: April 2014

Titania (TiO2) as a semiconductor has been intensively studied during the last decades. Regardless of its superior photocatalytic performance and extensive environmental applications, it has a wide bandgap which lead to a photocatalytic activity only in ultraviolet (UV) irradiation. To shift the activity of TiO2 to visible region, a series of monometallic and bimetallic doped TiO2 was prepared with 10wt% total metals loading. The photocatalysts were synthesized by sol-gel associated via hydrothermal method. The properties of the photocatalysts such as crystal size, surface morphology, total surface area, chemical state of the elements, and bandgap were investigated by using thermogravimetric analysis (TGA), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) measurement. XRD analysis showed that all samples displayed anatase (101) as a main phase of TiO2 with average crystal size between 10-16 nm in a good agreement with the TEM results. The FESEM images show spherical particles less than 20 nm in size. The BET results indicated that all samples are mesoporous. The band gap of Ni-Cu/TiO2 is reduced to 2.65 eV with more absorbance in the visible region compared to those of cu/TiO2 and Ni/TiO2.
Synthesis and Film Formation of Neodymium Oxides Nanorods: Electrical Properties Study
Authors: Hamza Ammar M. , Hassan M. Shamshi , Awad Ahmed N.
Published: April 2014

Neodymium Oxides (Nd2O3) nanorods could be obtained via calcining the corresponding lanthanide nitrite counterparts without any impurities highly crystalline at 600 Co for 2 hr. The products were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results showed that the Nd2O3 nanorods with hexagonal phase have different diameter and length. The I-V characteristic of the Ag/(Nd2O3) film is shown very low leakage current due to crystallinity and hence suitable for organic thin film transistors.
Post-Annealing Effects on ITO Thin Films RF Sputtered at Different Thicknesses on Si and Glass
Authors: Ali Ahmad Hadi , Abu Bakar Ahmad Shuhaimi , Bakhori Siti Khadijah Mohd , Zainuriah Hassan
Published: April 2014

We report on electrical, optical and surface morphological characteristics of indium tin oxide (ITO) thin films. The ITO was deposited by radio frequency (RF) magnetron sputtering on Si and glass substrates at different thicknesses of 125 nm and 239 nm. Post-annealing treatment was conducted on the samples at temperature of 500°C and 600°C. From Hall Effect measurement, the lowest resistivity was measured as 4.4 × 10-4 Ωcm and 4.5 × 10-4 Ωcm corresponding to the 239 nm and 125 nm ITO sample, respectively, after post-annealed at 600°C. Using UV-Vis spectrophotometer, the highest transmittance of ~84% at 470 nm was observed with respect to the 125 nm ITO thin films after post-annealed at 500°C. Furthermore, the 500°C post-annealed 125 nm thin film shows highest carrier concentrations of more than 1021 cm-3 and smoothest surface morphology of 0.5 nm root-mean-square, RMS. It is clearly shown that post-annealing treatment on ITO thin films is able to enhance the electrical and optical transmittance properties as compared to the as deposited films.
A Comparative Study between the Effects of Oxidizing and Reducing Atmospheres on the Properties of ZnO-Bi2O3-Mn2O3 Varistor Fabricated from Micro and Nanoparticles Size of ZnO
Authors: Sendi Rabab Khalid , Mahmud Shahrom , Sirelkhatim Amna
Published: April 2014

Zinc oxide-based varistors are semiconductor ceramics. Their excellent nonlinear electrical behaviors are induced from their grain boundaries and depend on their microstructural characteristics. From a theoretical aspect, finer primary particles with narrow size distributions provide better electrical and optical properties. Thus, these properties are related to the morphology and size of ZnO grains. In this study, ZnO-Bi2O3-Mn2O3 varistors fabricated from ZnO micro-and nanoparticle powders are prepared via conventional ceramic processing. The effects of ZnO particle size and different annealing ambients on the properties of ZnO varistors are also investigated. The strong solid-state reaction during sintering may be attributed to the high surface area of the 20 nm ZnO nanoparticles that promote strong surface reaction. The annealing process also improves grain crystallinity, as shown in the decrease in intrinsic compressive stress based on the X-ray diffraction lattice constant and full-width at half-maximum (FWHM) data. The reduced particle size significantly influences the electrical properties, showing a sharp drop in the breakdown voltage. Thus, the ZnO nanoparticles can be used to manufacture of varistors with superior properties and lower breakdown voltage compared with commercial ones.
Electrical Characterization of Al/Ag Contacts on Al-Zn Codoped SnO2 Thin Films Deposited by  Solid-State Chemical Vapor Deposition
Authors: Chuah Lee Siang , Tneh S.S. , Hassan Z.
Published: April 2014

Excellent tin oxide (SnO2) ohmic and Schottky contacts are need for device utilizations and essential electrical characterization. Up to now, metal contact property studies on SnO2 are inadequate and provide miscellaneous results. Ohmic contacts have been studied on high quality epitaxial n-type tin oxide thin films that were grown by solid state chemical vapor deposition (SSCVD). To the best of our knowledge, this is the first time that Al-Zn co-doped SnO2 films grown by SSCVD have been reported. Non-alloyed Al/Ag, Al, and Ag contacts were characterized by current-voltage measurements. Ohmic contacts were realized using Al, Ag , and Al/Ag after an air treatment of the SnO2 surface.
A44_ Effect of Nano-Sized ZnO on Electrical & Structural Properties of High Temperature Tl2-x HgxBa2Ca2Cu3O10-δ Superconductors
Authors: Fathi Sabah Jalal
Published: April 2014

The electrical resistivity of high temperature superconductivity Tl2-xHgxBa2Ca2Cu3O10- δ has been measured in the temperature range from 90K to 330K. These results showed that the critical temperature of the zero resistivity increases from 127K to 138K ,when the Hg concentration increased from 0 to 0.5. The structure of the Tl2-xHgxBa2Ca2Cu3O10-δ compound has also investigated by using X- ray diffraction technique. This compound has tetragonal type structure with a=b=5.36A & c=36.09A and the magnitude of c-axis increases to 37.8A when x increased to 0.5. Nano ZnO was add to the sample with concentration (0-1) wt% of the ( Tl2-xHgxBa2Ca2Cu3O10-δ) samples mass. The effect of the nano ZnO concentration substitution on the samples investigated on structure and critical temperature of the best sample properties (when x=0.5)and showed that the structure remains tetragonal and c-axis increased to 39.2A when nano sized concentration 0.8% and Tc increase to 146K but c-axis decreased to 38.4A and Tc decreased to 143K when the ZnO concentration 1%.
Fabrication Gallium Nitride (GaN) Nanowires by Thermal Chemical Vapor Deposition (TCVD) Technique
Authors: Abdullah Qahtan Nofan , Yam Fong Kwong , Yusof Yushamdan , Zainuriah Hassan
Published: April 2014

In this paper, low-dimensional gallium nitride (GaN) nanowires have been successfully grown on silicon substrate through thermal chemical vapor deposition (TCVD); no metal catalyst was used to assist growth of nanostructure. A high purity of gallium nitride powder was used as a starting material, evaporated at 1150 OC for 2 hour and then annealing at temperature 1000 OC under stable flow of ammonia (NH3) gas in horizontal quartz tube. The morphological investigation and crystalline and orientations growth of GaN nanostructure were carried out by employing scanning electron microscopy (SEM), high resolution X-ray diffractmeter (HRXRD). A room temperature micro-Raman spectrum were employed to study the optical properties and crystalline defects. XRD shows the diffraction peaks located at 2θ= 32.43, 34.57, 36.89, 48.05, 57.83, 63.62, 69.02, and 70.470 corresponding to the (100 ), (002), (101), (102), (110) , (103),(112 ) and (201) plane diffraction of GaN structure. These results revealed that the diffraction peaks can be attributed to hexagonal GaN phase with lattice constant of a = 3.190 A° and c = 5.1890 A°. Here we report on the growth of GaN nanowires on Si (111) substrate by CVD . This technique is much simpler and cheaper than such techniques as MBE, MOCVD and HVPE.
Fabrication of Poly-Si Nanowire Using Conventional Photolithography Technique
Authors: Nuzaihan Mohammad , Hashim Uda , Nazwa Taib , Ruslinda A. Rahim
Published: April 2014

A simple method for the fabrication of polycrystalline silicon (poly-si) nanowires using conventional photolithography combined with thermal oxidation-size reduction method is presented. In our process, a polysilicon layer is deposited by low pressure chemical vapour deposition technique on SiO2 layer. Conventional photolithograpy is used to define the initial poly-si of dimensions 1 um. In order to miniaturize microwire to nanowire, size reduction method is employed using several time of dry thermal oxidation process. The characterization that is applied to measure the profile of poly-si nanowires using optical microscopy.
Development of Hybrid WO3-TiO2 Nanotubes for Solar Hydrogen Generation via Water Electrolysis
Authors: Lai Chin Wei , Lau Kung Shiuh
Published: April 2014

Solar hydrogen (H2) generation from water electrolysis is a key target for the development of sustainable hydrogen economy for future energy system. The formation of self-organized and highly ordered titania (TiO2) nanotubes is essential for high efficiency in photoelectrochemical (PEC) water electrolysis application. Based on our preliminary studies, highly ordered TiO2 nanotubes were successfully synthesized through anodization of titanium (Ti) foil in ethylene glycol (EG) containing 5 wt% of ammonium fluoride (NH4F) and 5 wt% of hydrogen peroxide (H2O2) at 60 V for 1 h. However, an obvious hindrance to the widespread use of TiO2 nanotubes as a photoelectrode in PEC water electrolysis system is its poor visible light response and rapid recombination of photo-induced electron/hole pairs. Thus, continuous efforts have been exerted to improve the efficiency of PEC water electrolysis by incorporating an optimum content of W6+ species into TiO2 nanotubes. In the present study, a practical technique of radio frequency (RF) sputtering was selected to incorporate W6+ species into TiO2 lattice. It was found that TiO2 nanotubes sputtered at high energy of 50 W for 30 sec demonstrated a maximum photocurrent density of ~ 2.4 mA/cm2 with photoconversion efficiency ~ 6 %.