bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Elastic Behaviour of Dies and Servo Press Machine on Deep Drawing Process
Authors: Watanabe Akihiro , Kotani Y. , Nishimura K. , Watari Hisaki , Yamazaki Takanori
Published: January 2010

Characteristic features of elastic deformation of dies and presses during deep drawing were measured to examine the effects of elastic deformation of the press and dies on product accuracy. Strains were measured on the press including dies, a slide and a bolster of a servo press. A strain magnitude of 63 ×10-6 was obtained when the slide position was at the lowest point. Two slide motions of the servo press were selected to determine appropriate manufacturing conditions. An elastic deformation analysis of the die structure was then performed by CAD simulation. To find an appropriate die structure model, the vertical displacement of the die structure in the CAD simulation was compared to the experiment results. It was found that the vertical displacement of the die structure was 0.147 [mm] at the top surface of the die when considering elastic deformation of the die structure as well as the bolster of the servo press.
Catalytic Activity of Oxidation-Reduction Pre-Treated Ni3Al for Methane Steam Reforming
Authors: Xu Ya , Chun Dong Hyun , Jang Jun Hyuk , Demura Masahiko , Wee Dang Moon , Hirano Toshiyuki
Published: January 2010

The catalytic activity of oxidation-reduction pre-treated Ni3Al powder for methane steam reforming was examined. The oxidation-reduction pre-treatment consisted of two steps: oxidation in air at various temperatures from 973 to 1373 K, and then followed by reduction in H2 at 873 K. It was found that the oxidation-reduction treatments significantly reduced the onset temperature of activity, i.e., improved the activity of Ni3Al powder at low temperatures. The characterization of Ni3Al surface showed that an outer surface layer of fine NiO particles were formed on the surface of Ni3Al after oxidation. These NiO particles were reduced to metallic Ni by the subsequent reduction treatment, resulting in the high activity for methane steam reforming. These results indicate that the Ni3Al can form highly active surface structure with oxidation-reduction treatment, having excellent heat resistance.
The Nano Carbide Control: Design of Super Ferrite in Steels
Authors: Yen Hung Wei , Huang Chi Yuan , Yang Jer Ren
Published: January 2010

The ferrite phase strengthened by the highly dense nanometer-sized carbides is named super ferrite. The effects of Ti, Ti-Mo, and Ti-Nb micro-alloy additions on the precipitation strengthening in three experimental high-strength low-alloy steels have been investigated by using transmission electron microscopy and micro-hardness measurement. The objective of this work was to study the carbide precipitation under the conditions of isothermal transformation. It was found that interphase precipitation of nano-sized carbide in Steel Ti-Mo had very strong contribution to the hardness of the steel. The distribution of interphase precipitated carbides is associated with both the sheet spacing and the inter-particle spacing, which have been studied. The result implies that (Ti, Mo)C particles possess an excellent effect on precipitation hardening.
Surface Repair of Tool Made of 12 Ni Maraging Steel by Laser Cladding of NiCoMo Powder
Authors: Bergant Zoran , Grum Janez , Slabe Janez Marko , Ocaña José Luis
Published: January 2010

Surface repair experiments with Nd:YAG coaxial laser cladding of NiCoMo maraging powder were made on specimens from maraging steel (EN 10027-2, mat. no. 1.2799). The influences of different modes of laser-beam guidance with various powder mass flows and with different degrees of overlapping of individual traces on the dilution and the repair area were determined. The micro and macroscopic analyses of microsections of fusion zone (FZ), heat affected zone (HAZ) and through-depth microhardness were analysed after cladding and after subsequent solution and precipitation annealing. The microchemical (EDS) analysis was performed at various depths. The residual stresses in the clad face and in the clad toe were determined and compared, using the hole-drilling method.
Coupled Numerical Simulation of Process in Rheocasting-Rolling for Semi-Solid Magnesium Alloy Used By Slope
Authors: Zhang Ying , Xie Shui Sheng , Geng Mao Peng , Guo Hong Min , Zhao Hai Bo , Xu Jin Hua
Published: January 2010

By the finite element method, the N-S momentum, energy equations and continuum equations, etc. which describe the fluid flow and heat transfer in the slope of the rheocasting-rolling for Semi-solid Magnesium Alloy were computed. The influence of the different slope parameters( pouring temperature, length of slope, lean angle)on the metallographic structure of semi-solid magnesium alloy was analyzed. The simulative results can provide effective data to confirm optimized slope size and technical parameter.
Using the Plunging and Welding Process Windows to Determine a FSW Means of Production
Authors: Zimmer Sandra , Langlois Laurent , Laye Julien , Goussain Jean Claude , Martin Patrick , Bigot Régis
Published: January 2010

This paper presents an experimental methodology to determine a Friction Stir Welding (FSW) means of production based on the experimental study of the tool / material mechanical interactions generated during the plunging and welding stages. These two stages have been identified as being characteristic for the qualification of a FSW equipment. This paper presents the experimental results of the parametric study done on the plunging and welding phases. Ranges of forces and torques diagrams were established according to the processing parameters, in order to qualify a means of production and select the process parameters allowing the operation on the available FSW equipment.
Stress Analysis on the Stretch Forming of the Aluminum Saddle-Shaped Skins
Authors: Huang Chi Kong , Torng Chau Chen , Chang Hsien Ming
Published: January 2010

The stretch forming applied force during the forming process and exceed the yield stress of the raw material to make the part deforming plastically, and fitting the contour of a form block, then the purpose of forming can be reasonably achieved. The saddle-shaped skin located in the mating area between the vertical stabilizer and the empennage. This study investigates the stress distribution on the stretch forming of saddle-shaped skins. First, apply the FEM software-ABAQUS to analyses the stretch forming of saddle-shaped skin. Then use the statistical method to analysis the stress in different forming conditions. Finally, the stress of saddle-shaped skins on the critical location is analyzed and discussed. This study aims to modify the process parameters in advance to prevent the failure and defects of skin and provide valuable information for both production engineer and tool designer to improve their design of process parameters and form block.
Stress Corrosion Cracking Behaviour of Welded Duplex Stainless Steel
Authors: Khoshnaw Fuad Mohamed , Rahmatalla Hussein Bakir
Published: January 2010

This study investigated stress corrosion cracking of two welded stainless steel alloys, austenitic 304L and duplex 2205, in an acidic chloride solution. Different heat inputs are selected for welding the alloys, using tungsten inert gas, with and without filler metal. The slow strain rate technique is utilized to estimate the susceptibility of each weldment to stress corrosion cracking. Different strain rates are used, and the experiments showed that the strain rate equal to 1.66x10-6/sec is a critical value that can be used for assessing the susceptibility of the alloys to corrosion cracking. A numerical index used in this study to evaluate this susceptibility, which is based on a ratio between elongation percent of each alloy in the solution to that in the air.
The results showed that the austenitic alloy has higher ductility than duplex in air, while there was not a big difference between both alloys in the solution. Increasing the heat input in autogenous welding caused a brittleness, i.e. less elongation, for both alloys. The results showed that the austenitic alloy is exposed to stress corrosion cracking in the solution, before and after welding, with or without filler metals. On the other hand, the duplex alloy showed higher resistance to stress corrosion cracking than the austenitic alloy due to the high chromium content, and it is dual phase.
Effect of Austenite Deformation on Recrystallisation Behaviour in an X-70 Microalloyed Steel
Authors: Sun Lin , Wynne Bradley P. , Palmiere Eric J.
Published: January 2010

In the present study, the effect of austenite deformation on the recrystallisation behaviour in terms of recrystallisation-stop and recrystallisation-limit temperatures (T5% and T95%) of an X70 niobium microalloyed pipeline steel have been investigated by interrupted plane strain compression tests. The extents of recrystallisation are calculated using a modified fractional softening parameter. And the 20% and 60% of fractional softening were correlated to T5% and T95%. Quantitative optical metallography indicates that this method provides for a convenient and reliable experimental measurement of the critical temperatures associated with the recrystallisation of austenite. The recrystallisation kinetics and the precipitation kinetics of Nb(CN) were calculated using two widely applied models. The experimental results from this study suggest that the current model of precipitation kinetics might overestimate the precipitation start time.
TEM Study and Magnetic Measurements of Nano–Scale Particles Formed in Cu–Base Alloys
Authors: Kang Sung , Muramatsu Teppei , Takeda Mahoto
Published: January 2010

The precipitation behavior of nano–scale particles formed in Cu–base alloys was studied by means of transmission electron microscopy (TEM) and SQUID measurements. Linear arrangements of two or more nano–scale particles cubic in shape were observed in the <100> orientations of matrices in a Cu–Co alloy. Although the trend was less explicit in a Cu–Fe alloy, Fe precipitates accompanying twin–like lattice modulations were found in the decomposition, when no deformation was applied. The present SQUID measurements revealed several significant influences to magnetic properties were induced during the precipitation in Cu–base alloys. Lorentz electron microscopy confirmed that phase transformation from γ → α occurred at the stage that the Fe particles reach to 40~60nm in size.
Effect of Thermomechanical Processing on Structure and Corrosion-Mechanical Properties of AISI 321 Steel
Authors: Kodzhaspirov G.E. , Rudskoy A.I. , Rybin V.V.
Published: January 2010

The effect of Thermomechanical Processing (TMP) on the fine structure (dislocation density and fragments evolution), recrystallization, carbide transformations and tendency toward intercrystalline corrosion (ICC) and corrosion-mechanical strength of AISI 321 type steels is described. It’s shown that the grain size and overall amount of carbide phase has almost no effect on ICC. With an increase in dislocation density a tendency is observed toward a reduction in corrosion rate, but increases with an increase in proportion of recrystallized material. This connection is explained by an increasing of the level of local microstresses, which may be arranged structurally in the form of partial disclinations and aggravate ICC. A new test procedure was developed for estimating the corrosion-mechanical strength of steel. It follows from the obtained data that the hot working with the following accelerate cooling under industrial conditions does not develop a tendency toward corrosion cracking in 3% agueous NaCl solution.
Hydrothermal Synthesis of Luminescent Wollastonite-CePO4 Nanocomposites
Authors: Ma Ming Guo , Zhu Jie Fang , Sun Run Cang
Published: January 2010

Luminescent wollastonite-CePO4 nanocomposites have been successfully synthesized using Ca(NO3)2•4H2O, Na2SiO3•9H2O, and CePO4 by hydrothermal method at 200 oC for 24 h. The precursor nanorods with diameters about 20 nm and lengths several micrometers were obtained by hydrothermal treatment, and after calcination at 600 oC for 3h, the precursor nanorods transformed to wollastonite-CePO4 nanocomposites. Considering the experiment result, a possible growth of the precursor nanorods via the rolling mechanism was also proposed. This is the first report about the synthesis of luminescent wollastonite-CePO4 nanocomposites. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDS), and photoluminescence (PL).
A Novel Combined Flowsheet of Beneficiation and Acid Leaching under High Pressure for Complex Lead-Zinc Ores
Authors: Zhang Han Ping , Wang Xiao Li , Wang Xu Ming , Jian Sheng , Zhao Qun
Published: January 2010

The run-of-mine of complex lead-zinc ores in Yunnan contains 3.26% lead and 2.54% zinc. When traditional selective flotation flowsheet was adopted, 3.77% yield and 61.92% grade of lead concentrate as well as 5.65% yield and 38.67% grade of zinc concentrate were achieved. Simultaneously, 72.39％ lead recovery and 3.83% zinc grade in lead concentrate as well as 80.64% zinc recovery and 6.39% lead grade in zinc concentrate were obtained. Lead concentrate and zinc concentrate obtained from selective flotation contain each other severely, resulting in low recovery of lead and zinc and severe loss of metal, which influences subsequent smelting flowsheet. In addition, due to requirement of large amount of depressant and activator while separating lead and zinc in the process of mineral processing, the cost is very high and the compositions of tail water which can not be recycled by the plant are very complicated. For the combined flowsheet of beneficiation and metallurgy, bulk flotation flowsheet was adopted. Therefore, 11.22% yield of combined lead and zinc concentrate with 25.55% lead grade, 18.33% zinc grade and 86.36% lead recovery were obtained. Gravity separation technology was utilized to separate combined concentrate of lead and zinc. After selecting out part of high quality lead concentrate, the remaining combined concentrate of lead and zinc was treated by acid leaching under high pressure. The final leaching efficiency of zinc was able to reach 97%. The new combined flowsheet has lots of advantages such as shorter flowsheet of beneficiation, simpler reagents, more direct reuse of backwater and higher recovery of metals.
Microwave-Assisted Controlled Synthesis of CaCO3 with Various Biomimetic Morphologies Using Basic Additives in Polyol
Authors: Ma Ming Guo , Jiang Jian Xin , Sun Run Cang
Published: January 2010

CaCO3 (aragonite or calcite) with various unusual biomimetic morphologies, such as pumpkin-like, olive-like, willow-leaf-like, cauliflower-like, etc, have been successfully synthesized by one-step microwave-assisted method using CaCl2, (NH4)2CO3 or Na2CO3, basic additives (urea, hexamethylenetetramine ((CH2)6N4), ethylenediamine (C2H8N2) and NaOH), poly(vinylpyrrolidone) (PVP)) in polyol. The effects of reaction temperature, reaction time, and type of basic additive on the products were investigated. The reaction temperature and type of basic additive have significant effects on the morphology of CaCO3. This method is simple, fast, low-cost and may be scaled up for large-scale production of CaCO3 with various morphologies.
Preparation and Electrochemical Properties of LiFePO4/PPy Composite Cathode Materials for Lithium-Ion Batteries
Authors: Ren Xiang Zhong , Li Xi , Zhang Pei Xin , Liu Jian Hong , Zhang Qian Ling
Published: January 2010

LiFePO4/PPy composites with different content of polypyrrole (PPy) were prepared by chemical oxidation reactions. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the LiFePO4/PPy composite. The results showed that doped PPy did not destroy the olivine structure of LiFePO4 but decreased the intensity of the diffraction peaks, and PPy was found on the surface of LiFePO4 particles. PPy could remarkably increase the conductivity of the composite and improve the electrochemical performance of LiFePO4. The sample with 2.5 % (wt). PPy possessed a high initial discharge capacity of 144.5mAh/g at 0.1C. The results of both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) proved good cycle performances of the samples doped by PPy.
Preparation of Carbon Materials with Different Morphologies
Authors: Cai Pei Jun , Cao Yi Jun , Li Xiao Bing , Shi Mei
Published: January 2010

In this paper, carbon materials with solid and hollow sphere morphologies, have been prepared by reduction of hexachlorobenzene with metallic sodium at temperatures of 400-500°C for 6-10h. Characterized by XRD, TEM, SAED and Raman spectrum, the composition and morphology of the products are confirmed. The possible formation mechanism has also been proposed.
Preparation of Liposome Particle of Atractylone by Supercritical Carbon Dioxide Process
Authors: Wen Zhen , Liu Bo , Zheng Zong Kun , You Xin Kui , Pu Yi Tao , Li Qiong
Published: January 2010

The liposome particle entrapping atractylone extracted from Atractylodes macrocephala Koidz.was prepared and characterized. The liposome suspension of atractylone was formed by supercritical carbon dioxide (SC-CO2) expansion process and was dried by vacuum freezing. The physicochemical properties of the liposome particle including microstructure, size, entrapment efficiency and drug loading content were measured. The liposome formation could be controlled by adjusting the processing conditions such as pressure, temperature of SC-CO2 and mole fraction of ethanol in SC-CO2 [ x (CH3CH2OH)]. The entrapment efficiency, loading content, and average size of liposome particle were 83.1％, 5.1％ and 506.5nm respectively under the optimum conditions of 30MPa，338K and x (CH3CH2OH) = 15％.The liposome particle presented good performance of redispersion to liposomal suspension. The physicochemical properties of liposome particle including entrapment efficiency, dissolution rate and stability complied with the provisions of Chinese pharmacopoeia. The results show the liposome particle can be used as an solid immediate for hepatic target of drugs.
Relationship of Particle Content and Size of Spherical Silica with the Flowability of Epoxy Molding Compounds for Large-Scale Integrated Circuits Packaging
Authors: Yang Ming Shan , Liu Yang , He Jie , Li Lin Kai , Wang Ze
Published: January 2010

The melting viscosities of different kinds of epoxy resins have been investigated in this paper. The results showed that tetramethyl biphenyl epoxy resin(TMBP) has very low melting viscosity(0.02Pa•s at 150°C) and can be blended with ortho-cresol novolac epoxy resin(ECN) in order to decrease the melting viscosity of epoxy molding compound(EMC). When the content of TMBP in the blend of ECN/TMBP was up to 40wt%, the viscosity of the blend decreased to 0.15 Pa•s from 0.8 Pa•s of ECN. In addition, the effects of the content, particle size of silica on the flowability of EMC have been researched systematically in the paper. The results showed that the melting viscosity of EMC increased greatly with the filling increasing of silica, and the particle size and the match of silica with different particle diameter had markedly influenced on the flowability of EMC. The melting viscosity of system with higher filling content of silica changed complicatedly with the increasing of shear rate, i.e., the viscosity of the system decreased with the increasing of shear rate in the range of low shear rate, then increased with the increasing of shear rate in the range of high shear rate, but decreased again with the increasing of shear rate in the range of higher shear rate. The system filled by silica with small particle diameter had low melting viscosity at low shear rate and high melting viscosity at high shear rate, but the melting viscosity of the system filled by silica with large particle diameter changed by contraries.
Research of Improving Water Injection Effect by Using Active SiO2 Nano-Powder in the Low-Permeability Oilfield
Authors: Wang Ke Liang , Liang Shou Cheng , Wang Cui Cui
Published: January 2010

SiO2 nano-powder is a new type of augmented injection agent, has the ability of stronger hydrophobicity and lipophilicity, and can be adsorbed on the rock surface so that it changes the rock wettability. It can expand the pore radius effectively, reduce the flow resistance of injected water in the pores, enhance water permeability, reduce injection pressure and augment injection rate. Using artificial cores which simulated geologic conditions of a certain factory of Daqing oilfield, decompression and augmented injection experiments of SiO2 nano-powder were performed after waterflooding, best injection volume of SiO2 nano-powder under the low-permeability condition was selected. It has shown that SiO2 nano-powder inverted the rock wettability from hydrophilicity to hydrophobicity. Oil recovery was further enhanced after waterflooding. With the injection pore volume increasing, the recovery and decompression rate of SiO2 nano-powder displacement increased gradually. The best injected pore volume and injection concentration is respectively 0.6PV and 0.5%, the corresponding value of EOR is 6.84% and decompression rate is 52.78%. According to the field tests, it is shown that, in the low-permeability oilfield, the augmented injection technology of SiO2 nano-powder could enhance water injectivity of injection wells and reduce injection pressure. Consequently, it is an effective method to resolve injection problems for the low-permeability oilfield.
Study of Mechanical Properties of Magnesium Oxysulfate Whisker/ABS Composites
Authors: Jiang Yu Zhi , Li Yan Bo , Han Yue Xin , Yin Wan Zhong
Published: January 2010

The magnesium oxysulfate whisker/ABS composites were prepared by making the magnesium oxysulfate whisker as dispersed phase.Scaning electron microscope(SEM) was used to test the distribution of whiskers in ABS matrix.Effect of the surface modification and the amount of whiskers to the mechanical properties of composites were studied.The results show that,the surface modification can improve effectively dispersity both itself and in ABS matrix,interface acting force between ABS matrix and whiskers, and mechanical properties of composites ,remarkably.When the mass ratio of whisker to ABS is 40/100,the composite owns the optimum mechanical properties(Tensile strength,elastic modulus,and elongation at break are 67.5Mpa, 7.50Mpa,4.70%,respectively), whiskers distribute uniformly in matrix and improve the dimensioned stability of composites.The reinforcement mechanism of whiskers in ABS was also studied to explain the experimental results.
Study on Process and Mecahnism for Preparation of Magnesium Hydroxide Whiskers
Authors: Jiang Yu Zhi , Han Yue Xin , Yin Wan Zhong , Li Yan Bo
Published: January 2010

Taking alkaline magnesium sulfate whiskers and sodium hydroxide as raw materials, the proper process parameters were experimentally investigated for magnesium hydroxide whiskers preparation by hydro-thermal synthesis. The experimental results show that satisfactory product of magnesium hydroxide whiskers can be obtained under the proper synthesis conditions. The whiskers are characterized with smooth surface, straight morphology, and small diameter. The whisker product of magnesium hydroxide is of less than 0.5μm in diameter, around 100 in slenderness ratio, and 99.69% in purity under the condition of 4.0% initial concentration of alkaline magnesium sulfate whisker, stirring intensity of 100rpm, reaction temperature at 180°C, and reaction time of 4h. The synthetic mechanism of the whiskers was analyzed by the theories of anion coordination polyhedron nucleation and screw dislocation growth of the crystal.
The Effect of Nanometer Accessory Ingredient on the Function of Water Paint
Authors: Ying Peng Zhan , Fu Hong , Jia Liang Ju , Yu Lei , Chen Dong Yong
Published: January 2010

The addition of nanometer accessory ingredient in the paint to improve the function of the traditional paint has been the hot topic in the field of anticorrosive paint research. In this paper, three kinds of water nanometer accessory ingredients including anti-abrasive cleaner, hydrophobing agent and anti-aging agent has been added into the paint to combine the nanometer denaturizing paint. The functions of nanometer denaturizing paint such as shellac’s adhesive force, resistance to water, resistance to alkali , and hydrophobic property were measured to evaluate the effect of the accessory ingredint according to the related test standard. It was found that the type and the quantity of nanometer accessory ingredient can effectively modify the function of the water paint. Finally, the optimum parameters were obtained.
Crystallization Behavior and Performance of MgO-Al2O3-SiO2 Glass-Ceramics by Sintering
Authors: Zhang Pei Xin , Gao Li , Yuan Qiu Hua , Peng Hai Lin , Ren Xiang Zhong , Zhang Dong Yun
Published: January 2010

The glass-ceramics of MgO-Al2O3-SiO2 system were prepared by sintering technology. The crystallization process of MgO-Al2O3-SiO2 glass-ceramics was investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM), and other techniques; the discussion of breaking strength, thermal expansion coefficient and relevant properties at different sintering temperatures was also presented. The results show that: (1) The main crystalline phase isα-cordierite at different sintering temperatures, and the samples show high flexural strength and low thermal expansion coefficient; (2) with the increase of sintering temperature, the content of crystal phase increases, while the thermal expansion coefficient decreases evidently, the flexural strength and tightness density rise up first, then go down.
A Novel Method for Preparation of Carbon Coating Iron Nanoparticles
Authors: An Yu Liang , Hou Qing Yi , Yuan Xia , Zhang Gang
Published: January 2010

A novel and practical route for preparing carbon coating metal nanomaterials using polyvinyl alcohol as the starting materials was presented. Carbon coating iron nanoparticles can be effectively synthesized by carbonizing polyvinyl alcohol using Fe as catalyst in hydrogen flow. The carbohydrate was carbonized in a controllable way that leads to a large amount of carbon coating iron nanoparticles. Transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) and thermogravimetric analysis (TG) were employed to characterizing nanomaterials. The growth mechanism of carbon coating iron nanoparticles is briefly discussed in term of composition and structure of precursor.
Dispersion and Behavior of Silane Coupling Agent to Surface Modification of n-Cu Particles
Authors: Wang Xiao Li , Zhang Bo , Zhao Yang , Xu Yi , Xu Bin Shi
Published: January 2010

The prepared n-Cu particles with the particle size about 20 nm by KBH4 reduction method in aqueous solution was surface modified using silane coupling agent. The surface modification mechanics was researched. The tribological performances of n-Cu particles were tested by friction wear test machine. The results show that the modified n-Cu paritcles by silane coupling agent have high purity, good dispersion performances and wonderful surface activity. In friction process, the modified n-Cu particles can form a layer of organic-inorganic compound film with synergistic effect on worn surface, which improves the tribological performances of friction material.
Flotation and Purification Research on Low Grade Magnesite in Kuandian of Liaoning
Authors: Li Qiang , Yin Wan Zhong , Zhu De Shan , Lv Zhen Fu
Published: January 2010

Low grade magnesite coexisting with dolomite was purified by flotation. A process of reverse flotation to remove silicate minerals- positive flotation to concentrate magnesite was explored after the systematic process mineralogical investigation. Influence of different conditions such as grinding fineness experiment, collector experiment and combined modifiers experiment was also investigated. Open-circuit flotation test was carried out under the optimum conditions. It was showed in the result that the MgO content in concentrate was increased from 32.36% to 42.25%, the CaO and SiO2 contents in concentrate were decreased from1.08% and 17.70% to 6.73% and 0.19% respectively, but the recovery of MgO was not satisfactory.
Effect of Plasticizers on the Mechanical Properties of Cellulose Laurate Films
Authors: Hongphruk Panita , Aht-Ong Duangdao
Published: January 2010

The synthesis of cellulosic plastic films from waste cotton fabrics under homogeneous conditions by microwave heating using lauroyl chloride as an esterifying agent was studied. Nevertheless, the cellulose laurate film obtained was quite brittle than some other commercial synthetic polymers. Thus, the aim of this work was to investigate the effects of plasticizer on the properties of cellulose laurate film. Cellulose laurate was plasticized with each plasticizer, triethyl citrate (TEC), dibutyl phthalate (DBP), and epoxidized soy bean oil (ESO) at different amounts. The content of plasticizer was varied from 3% to 9% w/w of dry cellulose laurate. The effects of plasticizer (i.e., type and content) on mechanical properties of plasticized cellulose laurate films were investigated. The morphology and structure of cellulose laurate were confirmed by SEM, FTIR, and 1H-NMR analysis, whereas the thermal properties were characterized by TGA.
Chemical Synthesis and Characterization of Bismuth Vanadate Powder
Authors: Pookmanee Pusit , Paosorn Sumintra , Phanichphant Sukon
Published: January 2010

Bismuth vanadate powder was synthesized by a chemical co-precipitation method. Bismuth nitrate and ammonium vanadate were used as the starting precursors. The yellow precipitated powder was formed after adding ammonium hydroxide until the pH of final solution was 7. The powder was filtered and dried at 60 °C for 24h and calcined at 200-400 °C for 2h. The phase of bismuth vanadate powder was studied by X-ray diffraction (XRD). A single phase of monoclinic structure was obtained after calcinations at 200-400 °C for 2h. The morphology and particle size of bismuth vanadate powder were investigated by scanning electron microscopy (SEM). The particle was irregular in shape and highly agglomerated with an average particle size of 0.5 µm in width and 1.5 µm in length.
Effect of Temperature and Dwell Time on Phase Formation and Microstructure of β"-Alumina Solid Electrolyte
Authors: Kamonlert Amporn , Niyompan Anuson , Tipakontitikul Rungnapa
Published: January 2010

Powder of β-alumina solid electrolyte with general formula Na0.80Li0.20Al5O8 was prepared by solid state reaction according to the ternary systems Li2O-Na2O-Al2O3. All the calcined powders were heated at different temperatures for 1 h. The XRD results indicate that the β-alumina phase started to form at 1100 °C and these consistent with TG/DTA measurements. At constant calcined temperature of 1100 °C, When the dwell times was varied in range 5 h to 15 h, it was found that powder consists of β-alumina as a majority phase with a tiny amount of β-alumina and the β-alumina phase purity is about 82 wt% for dwell time of 10 h. The microstructures of β-alumina particles were seen as a layered structural arrangement with hexagonal shape and strong agglomeration between these particles are clearly seen.
Photocatalytic Degradation of Geosmin by Titanium Dioxide Powder Synthesized by the Hydrothermal Route
Authors: Pookmanee Pusit , Ninsonti Hathaithip , Sangsrichan Supaporn , Kangwansupamonkon Wiyong , Phanichphant Sukon
Published: January 2010

Titanium dioxide powder was synthesized by the hydrothermal route with the starting precursors as titanium isopropoxide, ammonium hydroxide and nitric acid. The final of pH value of mixed solution was 1 and treated in the hydrothermal PTFE vessel at 80-100 °C for 3h. The phase of titanium dioxide was characterized by X-ray diffractometer (XRD). The morphology of titanium dioxide was investigated by scanning electron microscope (SEM). The chemical composition of titanium dioxide was examined by energy dispersive X-ray spectrophotometer (EDXS). The photocatalytic degradation of geosmin by titanium dioxide was determined by gas chromatograph coupled with flame ionization detector (GC-FID).
Coloration in Soda-Lime-Silicate Glass System Containing Manganese
Authors: Srisittipokakun N. , Kedkaew C. , Kaewkhao Jakrapong , Limsuwan Pichet
Published: January 2010

The UV-visible spectra of soda-lime-silicate glass system with the base composition (65-x) SiO2: 10CaO: 25Na2O: xMnO2 % mol, (where x is 0.0, 0.02, 0.05, 0.10, 0.30 and 0.50 %mol) were studied at room temperature. The results are shown that the colors of glass samples were altered from colorless to dark purple with increasing of MnO2 concentration and were stable at room temperature. The color of glass sample with 0.3 %mol MnO2 was purple. Moreover, it has been found that the density and refractive index were contiguous. The optical absorption spectra can be confirmed the color of these glass samples. They exhibited a predominant broadband around 500 nm and it was clearly observed, its increasing since 0.1 %mol of MnO2. This band corresponds to an allowed transition from 5Eg5T2g, which attributed to Mn3+. When increasing MnO2 concentration, the absorption band due to Mn3+ ion was dominating.
Natural Fiber/PLA Composites: Mechanical Properties and Biodegradability by Gravimetric Measurement Respirometric (GMR) System
Authors: Tayommai Tanawat , Aht-Ong Duangdao
Published: January 2010

Polylactic acid (PLA), one of the most promising bio-based materials currently available on the market, has gained much attention recently as an alternative to non-biodegradable synthetic polymers due to its comparable properties and biodegradability. The objectives of this work were to prepare a green composite between PLA and coconut fiber (CF) to investigate an aerobic biodegradation of the biocomposites under controlled composting condition according to the ISO 14855-2. The composites were prepared at various ratios by a twin screw extruder and compression molding, respectively. Based on this research, the maximum content of coconut fiber added was 4 wt%. The addition of coconut fiber can improve the impact strength of the PLA composites. The increasing amount of coconut fiber had no effect on the specific tensile properties. The prototype of biodegradation testing unit - Gravimetric measurement respirometric (GMR) system - was successfully set up according to the ISO 14855-2 standard. The coconut fiber/PLA composite can be degraded significantly, i.e., 60 wt% within only 26 days.
Synthesis of Superhydrophobic Raspberry-Like Polymethylmethacrylate/Silica Core/Shell Particles
Authors: Hwang Ha Soo , Yuk Duck Soo , Ko So Hee , Park In
Published: January 2010

Silica-coated raspberry-like polymeric particles were synthesized based on the cationic colloidal particles which were prepared by soap-free emulsion polymerization of methylmethacrylate (MMA) in the presence of a cationic monomer, methacryloxyethyltrimethyl ammonium chloride (MOTAC) using azobis(isobutylamidine)hydrochloride (AIBA) as an initiator. The Stöber method has been adopted to coat silica on the surface of these cationic particles. Negatively charged Silica precursors were rapidly hydrolyzed onto the cationic surfaces of colloidal particles. The resulted polymethylmethacrylate-silica(PMMA-silica) core-shell particles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which clearly revealed that the PMMA-silica core-shell particles had the raspberry-like structure with 45nm wall thickness. Then, the fabrication of a superhydrophobic particle surface was achieved by coupling reaction of the PMMA-silica core-shell particle surface with nonafluorohexyltriethoxysilane. The water and oil static contact angle on the surface of the submicron-nano particles were 161° and 129°, respectively.
The Effects of Al2O3 Source on Phase Formation, Crystallite Size and Microstructure of Na-β"-Alumina Solid Electrolyte
Authors: Prachamon W. , Niyompan Anuson , Tipakontitikul Rungnapa
Published: January 2010

Na--alumina with MgO stabilized was produced through solid state reaction. High purity starting material, -Al2O3, -Al2O3, Na2CO3 and MgO were used. The desired amount of starting materials corresponding to the nominal formula Na(1+x)MgxAl(11-x)O17 were mixed and calcined at temperature 1200 for 10 h under atmospheric pressure. The effect of Al2O3 source on phase formation and averaged crystallite size of Na--alumina were investigated via X-ray diffraction (XRD), SEM and TGA/DTA. The XRD result show that formation of Na--alumina with high purity is obtained when -Al2O3 was used. The larger crystallite size is found for sample prepared form -Al2O3. For SEM study the Na--alumina microstructure is seen as randomly packing of several sheets. Calculated crystallite size of sample prepared from -Al2O3 show the larger value compared to that one prepared from -Al2O3.
Synthesis of 8 %mol Yttria-Stabilized Zirconia Powders by Mechanochemical Processing of ZrOCl2.8H2O and YCl3.6H20 with Li2CO3
Authors: Kumproa Kanatip , Nuntiya Apinon , Zhang Qi Wu , Saito Fumio
Published: January 2010

Mechanochemical processing of zirconium oxychloride and yttrium chloride precursors with lithium carbonate has been used to synthesis ultrafine powders of yttria-stabilized zirconia. The purposes of this work are to synthesis 8% mol yttria-stabilized zirconia powder via a mechanochemical process and to study the effect of LiCl as an inert diluent on agglomerate size of ultrafine powders. 8% mol yttria-stabilized zirconia powder was prepared from zirconium oxychloride and 8 %mol yttrium chloride precursors with lithium carbonate by using planetary ball mill and heat treatment. Chemical reaction between reactant mixtures occurs during post-milling heat treatment at low temperature to form composite powder. The products of this reaction consist of ultrafine powders embedded within LiCl as soluble salt by-product. The ultrafine powder is then recovered by removing the salt through a washing procedure. The powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis. The results indicated that 8% mol yttria-stabilized zirconia crystal structure depends on post-milling heat treatment temperatures. The structure of yttria-stabilized zirconia is transformed to a tetragonal form at 400 oC and 500 oC. Furthermore, it tends to form a cubic structure at 600 oC. However, agglomerate size of ultrafine powders also depends on the concentration of lithium chloride as an inert diluent and the washing procedure. Primary particle size of ultrafine powders is 30 nm.
Using Polymer Electrolyte Membranes as Media to Culture Fractals: A Simulation Study
Authors: Amir Shahizat , Nor Sabirin Mohamed , Hashim Ali Siti Aishah
Published: January 2010

In the authors' laboratory, fern-like fractals have been cultured in polymer electrolyte membranes of polyethylene oxide (PEO) doped with ammonium iodide (NH4I). The simulation study was then carried out utilizing the Diffusion Limited Aggregation (DLA) based on random motion of aggregating particles modelling technique. The fractal dimension values and the forms of the simulated fractals are comparable to those observed in the PEO polymer membranes. These indicate that the simulation using the DLA model done in this study has resulted outputs that are in abidance with the original fractals cultured in the polymer membranes.
Photocatalytic Hydrogen-Generation of Polyoxotungstate Nano-Clusters from Biomass
Authors: Fukaya Keisuke , Srifa Atthapon , Soottitantawatb Apinan , Grisdanurak Nurak
Published: January 2010

The photocatalytic reaction of polyoxotungstate, [BW12O40]5- and [SiW12O40]4-, led to the generation of hydrogen gas from biomass such as a sugarcane juice and tapioca starch under irradiation of UV light. These photoreactions were investigated in the pH dependence. The results showed that hydrogen was obtained at 2<pH<4. The photolysis of [BW12O40]5- and [SiW12O40]4- in presence of 60 ml of sugarcane juice at pH 2 level were obtained 0.15 ml and 0.51 ml of hydrogen, respectively. Especially, it was observed that the photolysis of the starch evolved oxygen without any catalysts. The oxygen contents affected to the reduced species of polyoxotungstates. Each photoreaction exhibited a different behaviour for the dependence of the amounts of catalyst. Lowering amounts of [SiW12O40]4- produced much hydrogen at pH 2 level. In contrast, lowering amounts of [BW12O40]5- could not evolve much hydrogen due to the domination of reoxidation of the reduced species by oxygen.
The Investigation on Ionic Conduction of PEMA Based Solid Polymer Electrolytes
Authors: Amir Shahrul , Nor Sabirin Mohamed , Subban Ri Hanum Yahaya
Published: January 2010

Solid polymer electrolytes comprising of various weight ratios of poly(ethyl methacrylate) (PEMA) and lithium perchlorate (LiClO4) salt were prepared via solution casting technique using N,N-Dimethylformamide (DMF) as the solvent. The conductivity values of the electrolytes were determined utilizing Solatron 1260. The highest conductivity obtained is in the order of 10-6 S cm-1. Structural properties of the electrolytes were investigated by X-ray diffraction and the results show that the highest conducting film is the most amorphous.
Fabrication and Characterization of Strontium-Doped Hydroxyapatite Bioceramics Scaffolds for Bone Implant Application: A Preliminary Study
Authors: Murad M.C. , Sopyan Iis , Rohaida C. , Ahmad Z. , Reusmaazran M.
Published: January 2010

In this study, strontium doped hydroxyapatite (SrHA) nanopowder was synthesized through a sol-gel method. Strontium concentration was varied from 0 to 15 mol%. The obtained gel was then dried and subsequently subjected to 900 °C calcination. SrHA porous bodies were fabricated by using polymeric sponge method with different chemical compositions (0, 2 and 10 mol% SrHA). To prepare the porous samples, the synthesized SrHA powders was mixed with distilled water and appropriate amount of dispersing agent followed by drying in the ambient air for 72 hours. The dried impregnated sponges were then sintered at 1300°C for 3 hours. The XRD patterns showed high crystallinity of HA phase only for all porous samples. Morphological evaluation by FESEM measurement revealed that the SrHA scaffolds were characterized by a uniform distribution of interconnected pores (200-800 µm). Compression test on the porous scaffolds revealed that doping 10 mol% of strontium in HA has increased the compressive strength compared to the undoped HA.
Development of Prolonged Action, Bioadhesive and Slowly Dissolving Minitablets
Authors: Choudbua Noppawan , Phaechamud Thawatchai , Ritthidej Garnpimol C.
Published: January 2010

Minitablets can be used either single or multiple unit sustained release dosage form. The objectives of this study were to prepare and evaluate the prolonged action, bioadhesive and slowly dissolving minitablets. The minitablets (Ø 2.5 mm, 7 mg) were prepared by direct compression method using 75%w/w of various hydrophilic polymers: hydroxypropylcellulose (HPC), hydroxypropyl methylcellulose (HPMC), carboxy methylcellulose (CMC), pectin (PT) and chitosan (CS). Spray dried lactose was used as diluent. Prior to compression, the angle of repose, bulk-tab density and %compressibility of each mixed powder were evaluated. The rate of hydration and erosion of the obtained minitablets were carried out in phosphate buffer (pH 7.4). The powder blends containing HPC, CMC or HPMC showed satisfactory flow properties and compressibility. Accordingly, the prepared matrix tablets of HPC, CMC and HPMC showed good physical properties such as hardness, while those of CS and PT showed poor properties. The degree of swelling were ranked as CS>CMC>PT>HPC>HPMC, while the erosion were ranked as CMC≈HPMC≈PT > HPC≈CS. Adhesion time of these minitablets on isolated pig intestine was >30 min for CMC, PT and CS tablets while HPC and HPMC tablets exhibited weaker bioadhesion. In conclusion, among tested polymers, CS, PT and CMC were appropriate for prolonged action, bioadhesive and slowly dissolving minitablets.
Conductivity and Dynamic Mechanical Studies of PVC/PEMA Blend Polymer Electrolytes
Authors: Zakaria N.A. , Yahya S.Y.S. , Isa M.I.N. , Nor Sabirin Mohamed , Subban Ri Hanum Yahaya
Published: January 2010

The ionic conductivity and mechanical properties of poly (vinyl chloride) (PVC)/poly (ethyl methacrylate) (PEMA) polymer blends containing LiN(CF3SO3)2 as doping salt has been studied using electrical impedance spectroscopy (EIS) and Dynamic Modulus Analysis (DMA) as a function of polymer blend ratios and lithium salt concentration. The film with PVC/PEMA composition of 65:35 obtained the highest conductivity with good transparency. DMA showed that both the storage modulus (E') and the glass transition temperature (Tg) of the PVC/PEMA is increased with PEMA concentration. In the case of PVC/PEMA-LiN(CF3SO2)2 films, the conductivity was found to increase with concentration of salt added with a maximum in conductivity at 35 wt.% LiN(CF3SO2)2. The Tg values of the doped films was found to increase with concentration of salt such that the film with the highest conductivity value has the highest Tg.
Structural Studies of Lead Sodium Borate Glasses
Authors: Limkitjaroenporn Pruittipol , Kaewkhao Jakrapong , Tuscharoen Suparat , Limsuwan Pichet , Chewpraditkul Weerapong
Published: January 2010

Glass compositions xPbO : 20Na2O : (80-x)B2O3 (x = 5,10,15,20,25,30,35,40,45,50 and 55 %mol) have been prepared using melt-quenching method. The density and molar volume of these glass samples have been found to be compositional dependent. The results indicate that PbO acts on the glass structures were different between the range 0≤ x ≤ 20 %mol and beyond x = 20 %mol (with inflection at x = 20 %mol). These due to the PbO can enter the glass network both as a network modifier and also as a network former. This role depends on the type of bond between lead and oxide. These results are interpreted in term of IR analysis.
Effect of 2-Amino 2-Methyl 1,3 Propanediol on Enteric Properties of Film Prepared from Ammoniated-Based Shellac Composite Salts
Authors: Meenabun Narumol , Limmatvapirat (1) Chutima , Limmatvapirat Sontaya
Published: January 2010

The aim of this study was to improve the enteric properties of shellac by composite salt formation with ammonium hydroxide (AMN) and 2-amino-2-methyl-1,3-propanediol (AMD). The shellac films were prepared by dissolving shellac with various combination of AMD:AMN and then characterized for physicochemical and mechanical properties. The results indicated that the solubility of shellac films was increased as increasing proportion of AMD. The percentage of dissolved film at pH 7.0 of 100:0 AMD:AMN (100%AMD) was approximately 3 times higher than that of 0:100 AMD:AMN (100% AMN) while the percentage of dissolved film at pH 1.2 was slightly increased as increasing proportion of AMD. These results suggested the solubility at intestinal pH was improved while the gastric protection was still in the acceptance level. The FTIR spectroscopy of all composite salts demonstrated the peaks at 1716 and 1556 cm-1, which were attributed to the carbonyl stretching of carboxyl and carboxylate groups, respectively. The absorbance ratio of FTIR peaks (ABS1556/ABS1716) was increased with the higher proportion of AMD, suggesting that the solubility enhancement was due to higher ionization degree of AMD salts. The mechanical properties of films were also changed after salt formation. As increasing the AMD:AMN ratio, the percent elongation of films has increased. The result suggested for more flexibility of films. In conclusion, the improved enteric properties of shellac films were achieved after composite salt formation with AMD.