bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystallization Behavior and Thermal Stability of Two-Glassy Phase ZR-Based Bulk Metallic Glasses
Authors: Tsai P.H. , Huang I.S. , Li T.H. , Jang Jason S.C. , Huang J.C. , Hsieh K.C.
Published: January 2010

Based on the thermodynamic calculation, two phase separated Zr-based BMGs (Zr63.8Ni16.2Cu15Al5 and Zr66Cu15.3Ni8.7Al10) which developed by the authors previous study were selected for investigating their crystallization behavior and thermal stabilities by means of differential scanning calorimetry (DSC), and X-ray diffractometry. The results show that the Zr66Cu15.3Ni8.7Al10 amorphous alloy exhibits higher GFA than the Zr63.8Ni16.2Cu15Al5 amorphous alloy. But the Zr63.8Ni16.2Cu15Al5 amorphous alloy presents higher activation energy of crystallization (227 kJ/mole and 188 kJ/mole for Zr63.8Ni16.2Cu15Al5 and Zr66Cu15.3Ni8.7Al10 BMGs, respectively). However, Zr66Cu15.3Ni8.7Al10 amorphous alloy contains less atomic percentage of Cu and Ni elements (with positive heat of mixing) may result in forming less volume phase separation as well less interface area between these separated amorphous phase. Overall, the Zr66Cu15.3Ni8.7Al10 amorphous alloy exhibits longer incubation time at higher annealing temperature in comparison with the Zr63.8Ni16.2Cu15Al5 amorphous alloy, suggesting that the amorphous alloy which contains fewer amounts of Cu and Ni elements would have better thermal stability.
Influence of Manganese on the Hot Working Behaviour of Construction Steels
Authors: Varela-Castro Gonzalo , Cabrera Jose María , Prado Jose Manuel
Published: January 2010

The microstructural control of rolled products is based on managing the austenite phase transformations during and after hot deformation to attain the desired microstructure after the cooling step. Therefore, it is very important an appropriate description of the kinetics of the hardening and softening phenomena taking place during the deformation at high temperatures, namely, dynamic recovery (DRV) and recrystallization (DRX). This investigation examines the effect of manganese contents on the hot flow behaviour of plain carbon steels. For this purpose, uniaxial hot compression tests were carried out in carbon steels in an extensive range of temperatures, from 1123 to 1373 K and strain rates, from 510-4 to 110-1 s-1. This work is focused in determining the physically-based constitutive equations that govern the plastic behaviour of plain carbon steels. Experimental results were compared with the predictions of the model and an excellent agreement over a broad range of temperatures and strain rates was obtained.
Direct Fabrication of a Ti-47Al-2Cr-2Nb Alloy by Selective Laser Melting and Direct Metal Deposition Processes
Authors: Vilaro Thomas , Kottman-Rexerodt V. , Thomas Marc , Colin Christophe , Bertrand P. , Thivillon L. , Abed S. , Ji V. , Aubry P. , Peyre Patrice , Malot T.
Published: January 2010

A Ti-47Al-2Cr-2Nb (at.%) material was fabricated using two laser-based methods, “Selective Laser Melting” (SLM) and “Direct Metal Deposition” (DMD), for potential uses in aircraft jet engines. Experiments were conducted under controlled atmosphere by changing the processing parameters. Optimal parameters were searched for this relatively low ductility material to prevent cracking due to built-up residual stresses during fast cooling. It was observed that these non-equilibrium cooling conditions were fast enough to generate ultra fine and metastable structures exhibiting high microhardness values. Post heat-treatments were successfully used to restore homogeneous lamellar or duplex microstructures and to relieve the residual stresses. A comparison of these two methods is provided in terms of powder requirements and of process parameters to achieve noncracked structures and fully dense materials.
Microstructure, Properties and Annealing Behavior of an ARB-Processed Al20%Sn Alloy
Authors: Bravo Agustín , Schouwenaars Rafael , Ortiz Armando , Jacobo Víctor H.
Published: January 2010

Severe plastic deformation processes are used to refine grain structure by means of very high deformations. Equivalent Von-Mises strains in the range of 5.06 to 11.57 were obtained using the accumulative roll-bonding (ARB) process. The effect of the initial microstructure is analyzed. Microstructure, microhardness and tensile strength of the alloy, both starting with previously cold-rolled material and after a 30 minute, 300 °C heat treatment, are compared. The effect of a heat treatment after 5 steps of ARB ( = 8.11) is also presented. Results show that even though both the microhardness and tensile strength go up with increasing deformation, they are not related to each other by a factor of 3. The highest values of these parameters depend more on the initial microstructure than on the total deformation. A better distribution of the second phase and an increase in solid solubility are also observed after ARB.
Material Constitutive Behaviour and Microstructure Study on Aluminium Alloys for Friction Stir Welding
Authors: Wang H. , Colegrove Paul A. , Mayer H.M. , Campbell L. , Robson Joseph D.
Published: January 2010

The material constitutive behaviour and microstructure of Aluminium alloys 6082 and 7449 were studied with the Gleeble hot compression test. The novel aspect of the work is that the testing was done at high strain-rates and at temperatures within 5 K of the solidus. The results indicated that the strength was maintained up to near solidus temperatures, with no dramatic strength reduction being observed. There was however, a distinct change in the slope observed with the 7449 results around 720 K. The experimental results were then fit to the Zener-Holloman equation, which describes the relationship between the material flow stress, temperature and strain-rates.
The material microstructure of the hot compression test samples was analysed, and the averaged grain size was calculated to compare with friction stir weld nuggets. This will be used to infer the processing conditions that exist in the dynamically recrystallized weld nugget. Finally, a simple model was used to understand how processing conditions affected the deformation behaviour.
Ultrasonic Welding Mild Steel Sheet to Al-Mg Alloy Sheet
Authors: Watanabe Atsushi , Watanabe Takehiko , Sasaki Tomohiro
Published: January 2010

Ultrasonic welding between SS400 mild steel sheet and aluminum alloy A5052 sheet containing magnesium was conducted. In this study, authors investigated the influence of ultrasonic welding condition on the mechanical properties and the interface microstructure of a joint, and examined the effect of an insert metal to improve the joint strength. The main results obtained in this study are as follows.
It was possible to ultrasonically weld SS400 mild steel sheet and A5052 sheet. When the clamping force was varied keeping the welding time constant for 1s, the joint strength showed the maximum at the clamping force of 588N and it decreased with increasing the clamping force because the frictional action at the interface decreased with it. When the clamping force was kept constant at 588N and the welding time was varied, the joint strength reached the maximum at the welding time of 2.5s, followed by decreasing in the joint strength welded at 3s welding time due to the formation of Fe2Al5 intermetallic compound at the interface. Using insert metal of commercially pure aluminum successfully improved the joint strength and the strength of the joint welded at 3s welding time was about three times larger than that without the insert metal.
Synthesis and Characterization of Cu and Ni Bearing Nano-Composites and Nano-Structured Alloys
Authors: Brocchi E.A. , Moura F.J. , Solórzono I.G. , Motta M.S.
Published: January 2010

It is well recognized the importance of nano-structured materials in the present technological stage. Due to their unique properties these materials can be used in a large number of applications. One example is the growing interest in nanocomposites, in which a very fine dispersion of a ceramic phase in a metal matrix will significantly improve the material properties. In view of that, extensive studies have been carried out on a variety of materials such as alloys and different types of composites. Recently, the authors have developed a novel chemical method for in-situ formations of Cu-Al2O3 and Ni-Al2O3 nanoscale composites by decomposition of their mixed nitrate solutions, to co-form the nano oxides, followed by preferential reduction of CuO or NiO by hydrogen at very low temperature. Studies carried out by the authors on the kinetics of reduction of such fine oxides indicated that under low partial pressure of hydrogen (0.25 atm) in argon, the oxides of Ni and Cu can be reduced completely, in a low temperature range of 523 to 623 K. The composites containing nanosized metal-metal oxide particles have been found to be quite homogeneous in nature. In view of this, Cu-Ni and Ni-Co alloys was also produced by mixing the respective aqueous nitrate solutions, followed by decompositions of their nitrates to their mixed oxides and subsequent low temperature hydrogen reduction. In that context, the purpose of the present work is to address the fundamental aspects of the synthesis procedure, emphasizing the basic thermodynamics background of the two steps involved. Also, the work aims to illustrate the outcome, by presenting experimental conditions and providing relevant characterization of the obtained nano-materials, by means of electronic microscopy and X-Ray Diffraction. Examples are given in terms of the obtained nano-composites and alloys.
Dynamic Growth of Ultra-Fine Austenite Grains Deformed above Ad3 Temperature in a Nb-V-Ti Steel
Authors: Yao S.J. , Du Lin Xiu , Liu Xianghua , Wang Guo Dong
Published: January 2010

Generally, three typical behaviors are recognized in hot-deformation of austenite. However, considering that those austenite grains involved in single-pass deformation are mostly on the scale of dozens of micrometers or even much larger than that, it is meaningful to investigate hot-deformation behaviors of austenite grains smaller than 10μm. In the current paper, austenite grains of different sizes were prepared through repetitive treatment of rapid reheating and quenching with changing the holding temperature and/or holding time. Kinds of true stress-true strain curves at 900oC and 950oC indicate that austenitic deformation can be gradually coordinated by grain boundary behaviors, such as grain boundary sliding and/or diffusion. Simultaneously, the macroscopic deformation is more likely to be dominated through co-operation grain boundary sliding (CGBS).
Tomographic and Topographic Investigation of Poly-D,L-Lactide-Co-Glycolide Microspheres Loaded with Prostaglandine E2 for Extended Drug Release Applications
Authors: Zehbe Rolf , Watzer Bernhard , Grupp Rainer , Halstenberg Sven , Riesemeier Heinrich , Kirkpatrick C. James , Schubert Helmut , Brochhausen Christoph
Published: January 2010

Polymeric, biodegradable microspheres represent a good reliable system to investigate the release of bioactive substances in both in vitro and in vivo applications. Common biomaterials for the synthesis of these microspheres are aliphatic polyesters of the poly(α-hydroxy)acids, especially poly-L-lactides (PLA) and polyglycolides (PGA) or their copolymers poly-D,L-lactide-co-glycolides (PLGA). In our own previous studies we have developed PLGA microspheres with integrated PGE2 as model substance for a wide range of biomedical applications, especially in angiogenesis, fracture healing and cartilage repair. The synthesis is based on a binary solvent in water emulsion approach, where two different solvents are used to dissolve the active agent and the polymer, while being miscible in each other (CHCl3, ethyl acetate). Both, the degradation of the material and the release profiles were investigated using SEM and mass spectrometry coupled with gas- or high performance liquid chromatography. SEM and AFM measurements indicated a porous structure of the microspheres but could not resolve the true three dimensional structure of the microspheres. Therefore, synchrotron radiation-based µCT (SR-µCT) investigations were performed to link the release profile to the structural design of the microspheres. As a result, we were able to cross validate the experimental data from SEM and AFM with SR-µCT, demonstrating both micro-porosity and nano-porosity. The polymer itself appears to consist of 200 nm – 300 nm sized particles.
Mechanical Properties of Csf/AZ91D Composites Fabricated by Extrusion Forming Process Directly Following the Vacuum Infiltration
Authors: Zhou Ji Ming , Qi Le Hua , Ouyang Hai Bo , Li He Jun
Published: January 2010

Magnesium matrix composites are attractive for weight critical application, such as automotive and aerospace components, because of its high specific strength and stiffness. Extrusion process directly following vacuum infiltration (EVI) can eliminate the porosity and obtain the well-aligned and uniform fiber distribution during the fabrication of Csf/AZ91D composite. This process combines the advantages of gas pressure infiltration, squeeze casting, and semi-solid extrusion. The mechanical properties of the magnesium are improved greatly by introducing the carbon fibers into the magnesium matrix through the EVI process.
In the present study, the carbon short fiber reinforced magnesium matrix composites Csf/AZ91D were fabricated by EVI process. The microstructure and tensile property of Csf/AZ91D composites were investigated. The results showed that the microstructure of the composite presented a uniform distribution of carbon short fibers in the matrix and good interfacial integrity. The yield strength and stiffness of the composites increased with increasing carbon short fiber content, but at the cost of ductility. Nonetheless, Csf/AZ91D can keep relatively high ductility during the improvement of strength compared with reported composites in the literatures. Increasing carbon fiber content in the composite was not always beneficial to the ultimate tensile strength at the same magnitude. When the fiber content exceeds 10%, the matrix was not strengthened as greatly as under 10% fiber content. The yield strength improvement was attributed to (i) load-bearing effects due to the presence of carbon short fiber reinforcements; (ii) grain size refinement due to the large extrusion deformation; (iii) generation of dislocations to accommodate CTE mismatch between the matrix and the particles.
The Effects of Friction and Lubrication on Multipass Hot Deformation
Authors: Funahashia S. , Palmiere Eric J.
Published: January 2010

Plane strain compression tests have been carried out to investigate the variation of friction coefficient for the ferritic stainless steel, AISI 430, during single and multi pass hit deformation using glass lubricant and BN. A graphical method has been employed to evaluate the friction coefficient. It is found that the friction coefficient declines as strain increases under slip friction conditions with glass lubricant. On the contrary, under partial sticking friction condition with BN, the friction coefficient increases as strain increases. Furthermore, the variation of the friction coefficient on multipass hit is almost identical with single hit until the second pass, but the value of the friction coefficient on the third pass is slightly higher than that observed following single pass deformation.
Hydrogen Embrittlement of Submicrocrystalline Ultra-Low Carbon Steel Produced by High-Pressure Torsion Straining
Authors: Todaka Yoshikazu , Morisako Kazunobu , Kumagai Masaaki , Matsumoto Yoshihisa , Umemoto Minoru
Published: January 2010

The tensile property and hydrogen embrittlement (HE) behavior in the submicrocrystalline ultra-low carbon steel produced by HPT straining were investigated. Elongated grains with 300 nm thickness and 600 nm length with high dislocation density were formed by the HPT straining at a rotation-speed of 0.2 rpm under a compression pressure of 5 GPa. The engineering tensile strength of the HPT processed ultra-low carbon steel for > 5 turns was 1.9 GPa, which is similar to the value of maraging high-alloy steels. The elongation increased with strain (at 5 to 10 turns), is caused by the reduction of the stress concentration due to the existence of continuously recrystallized grains. HE occurred in the HPT processed specimen for 5 turns with high tensile strength of 1.9 GPa under hydrogen atmosphere. However, its HE was suppressed via recovery process by annealing at low temperature while maintaining the high strength.
Microstructural Evolution during Spheroidization Annealing of Eutectoid Steel: Effect of Interlamellar Spacing and Cold Working
Authors: Caruso Matteo , Godet Stéphane
Published: January 2010

Eutectoid steels present a wide range of interesting mechanical properties (high strength, wear resistance, ductility and toughness) and could be a cheaper alternative to high strength low-alloyed steels (HSLA) in applications where weldability is not a critical requirement. The mechanical properties of pearlite are mainly dictated by the interlamellar spacing and the spheroidization of cementite. In this work, the spheroidization kinetics during annealing of a fully pearlitic steel produced in an electric arc furnace (EAF) is investigated. More specifically, the influence of a prior cold deformation and of the interlamellar spacing is studied using image analysis and hardness tests. It is shown that spheroidization is faster in fine pearlite than in coarse pearlite. Prior cold deformation strongly accelerates the spheroidization kinetics in fine and coarse pearlite. The tensile properties corresponding to different pearlite microstructure were measured and are compared to the hardness evolution during annealing.
A Facile Reaction for the Preparation of BN Nanospheres
Authors: Wang Yong Tian
Published: January 2010

In this paper we describe the synthesis of nanocrystalline boron nitride (BN) with a hollow morphology by the reaction of NH4BF4 and NaNH2 at 500 oC for 24h. Characterized by XRD, FTIR, XPS, TEM, and EDXA spectra, the composition and morphology of the products were confirmed. The possible formation mechanism was also discussed.
Large Scale Synthesis of Shuttle like CuO Nanocrystals by Microwave Irradiation
Authors: Cai Pei Jun , Shi Mei
Published: January 2010

Nanocrystalline CuO with shuttle-morphology has been prepared conventionally by a microwave irradiation heating technique from an aqueous system in the presence of Cu(CH3COO)2• H2O and NaOH at room temperature. The X-ray powder diffraction pattern indicates that the product is indicated that the product was pure monoclinic phase of CuO. Further characterized by transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy and Raman spectra, the component of the products were confirmed.
MgO-Al2O3-SiO2 Glass-Ceramic Prepared by Sol-Gel Method
Authors: Yuan Qiu Hua , Zhang Pei Xin , Gao Li , Peng Hai Lin , Ren Xiang Zhong , Zhang Dong Yun
Published: January 2010

The crystallization behavior of MgO-Al2O3-SiO2 glass-ceramics by sol-gel technology was investigated by using x-ray diffraction (XRD), differential thermal analysis (DTA), Scanning electron microscopy (SEM). The results showed that: (1)α-cordierite phase was precipitated when the green body was calcined at 1050°C, and α-cordierite of high purity and stability could be formed at 1100°C; (2) Adding an appropriate amount of low melting point glass powder into the green body may provide liquid-phase environment during the sintering process, which will help enhance the tightness density of glass-ceramic, and thus improve its flexural strength.
Physicochemical Characterization of Qianghuo Particles by Ultrafine Pulverization
Authors: Yang Lian Wei , Zhao Xiao Yan , Sun Peng , Gai Guo Sheng , Yang Yu Fen , Wang Yu Rong
Published: January 2010

Qianghuo, as a medicinal plant , has been demonstrated useful for the treatment of ache diseases in China. The physicochemical characterization of Qianghuo particles was greatly influenced by ultrafine pulverization. To study the physicochemical characterization of Qianghuo, the raw plant material of Qianghuo was ground to 5 μm particles by HSCS (High Speed Centrifugal Sheering) pulverizer. The micron particles were characterized by optical microscope and SEM. Ferulic acid is special chemical component of Qianghuo, and its extraction yield was determined to evaluate the chemical characterization of Qianghuo powder. Ferulic acid was analyzed by HPLC (High Performance Liquid Chromatography). The results showed that after ultrafine pulverization ,the plant cell walls were broken into pieces and the extraction yield of ferulic acid was increased by 30.24% compared with the original particles.
Preparation of Y2O3 Nano-Phased Powders by Polyacrylamide Gel Method
Authors: Luo Jun Ting , Zhang Chun Xiang , Gu Yong Fei
Published: January 2010

Y2O3 nano-phase powders were prepared by polyacrylamide gel method. The mechanism of polyacrylamide gel process and its calcinations procedure were analyzed. The high purity yttria powders can be produced by polyacrylamide gel method at the calcination temperature of 850°C, which is about 100°C lower than prepared by precipitation method. The microstructure of yttria powders prepared in different proportion of monomer and network agent was investigated. When the mole proportion of monomer and network agent is 5:1, the average size of grains is less than 20nm. Some grains grow abnormally if the proportion deviate from this value and there are a lot agglomerates. Development of such an inexpensive and easy technique for synthesis of high purity yttria nano-phase powders can be of commercial significance.
Research on Fuxin Plant Coal Ash as a Fluoride-Containing Wastewater and Mechanism of Fluoride Removal
Authors: Ma Zhi Jun , Han Yue Xin , Zhu Yi Min
Published: January 2010

Aimed at the status in China there are still some people who drink the water with excessive concentration fluorine, what may seriously threat to human health. For example Fuxin is an important production base in Liaoning province, which products aromatic compounds of fluorine. We found that the wastewater had large fluorine ion by testing the wastewater from the plant. It was polluted XiHe River and harmed to people’s health. So we chose the fly ash of Fuxin Plant as the agent to eliminate fluoride，then studied the mechanism of fluorine-removal and the physical properties of fly ash. Eventually we adopted the activation methods and combined the dynamic experiment and static experiment to research the mechanism to eliminate the fluorine with fly ash. The results of the experiment showed that the technology route was feasible which used the modified fly ash to get rid of the fluoride in the wastewater and reached the national emission standards.
Study on Size Distribution of the Copper and Nickel Ore
Authors: Zhao Li Bing , Han Yue Xin
Published: January 2010

Mineralogy research of the copper and nickel ore from Jinchuan is completed in detail that shows the mineral compositions and their percentage and particle size distributions of the valuable minerals. The main valuable minerals are pyrite, violarite, chalcopyrite which are closely associated with other sulphide minerals. These results provide an important basis for the beneficiation tests.
Study on the Surface Modification of Nanometer Calcium Carbonate
Authors: Wang Ze Hong , Chen Jing Hua , Yin Wan Zhong , Han Yue Xin
Published: January 2010

Titanate coupling agents KR-TTS is used to modify nanometer calcium carbonate and the modified powder is characterized. The modification mechanisms of nanometer calcium carbonate is also investigated in this paper. Experiment results show that the optimum conditions of dry modification method as follows: the dosage of KR-TTS titanate coupling agents is 2%, mass ratio of KR-TTS titanate coupling agents to liquid organic solvent is 1:1, modification temperature is 70°C, modification time is 20 minutes, stirring rate is 650rpm. Under the optimum conditions, activity index of modified nanometer calcium carbonate is 100%. The activity index Measurement indicates that modified nanometer calcium carbonate become hydrophobic instead of hydrophilic. IR analysis shows that chemical bonds are formed between titanate coupling agents and nanometer calcium carbonate particles.
Study on the Synthesis of High Quality Nanometer Calcium Carbonate Using Ultrasonic Technology
Authors: Yu Fu Jia , Wang Ze Hong
Published: January 2010

The synthesis of nanometer calcium carbonate was strengthened using ultrasonic technology. In the presence of ultrasonic, the effects of initial reaction temperature, density of Ca(OH)2 and flow rate of CO2 on nanometer calcium carbonate particles’ size were investigated in this paper. The homogeneous dispersion nanometer calcium carbonate particles which size were 20~30nm were synthesized using ultrasonic reactor.
Synthesis and Adsorption Property of Mesoporous Molecular Sieve MCM-41 from Iron Ore Tailings
Authors: He Yan , Lv Yang , Han Lu
Published: January 2010

The mesoporous molecular sieve MCM-41 was synthesized by hydrothermal synthesis method with iron ore tailings as starting material, and CTAB as appendage. The properties, kinetics and thermodynamics of Ni2+ from water adsorption process on MCM-41 residue were studied. The data demonstrated that the products possess typical properties of molecular sieve MCM-41, with specific surface area of 576 m2/ g, and the average pore size is 5.53 nm; the adsorption of MCM-41 residue to Ni2+ was decalescence reaction and the relationship between adsorbing capacity and equilibrium mass concentration is in accordance with the isothermal adsorption equations of Langmuir, and the removal rate of Ni2+ increases with the increasing of pH.
Synthesis of Nanocrystalline Ag-Cu Supersaturated Solid Solution by Mechanical Alloying
Authors: Li Liang Feng , Qiu Tai , Yang Jian , Feng Yong Bao
Published: January 2010

Nanocrystalline Ag-28Cu supersaturated solid solution is prepared by mechanical alloying (MA) using a planetary ball mill. The mechanical alloyed powders are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and differential scanning calorimeter (DSC). XRD patterns show that the main peak of Ag-28Cu supersaturated solid solution exists at about 2θ=39° when the milling time is 30h. HRTEM images show that the grain sizes of as-prepared solid solutions have distributions from 10nm to 15nm. The interplanar spacing of (111) plane for fcc Ag-28Cu supersaturated solid solution is about 2.24Å. DSC measurement result indicates that the melting temperature of Ag-28Cu supersaturated solid solution is 783.8°C. The Ag(Cu) supersaturated solid solutions are in metastable state and they will be transformed into Ag-rich phase and Cu-rich phase simultaneously by annealing at 215°C- 415°C.
The Reinforcement of Acicular Wollastonite on Polypropylene
Authors: Yang Ming Shan
Published: January 2010

The wollastonite/PP composites were manufactured by twin-screw extruder and the effects of compatabilizer, feeding method and screw configuration on the properties of wollastonite/PP composites were investigated in this paper. The dispersion of fibrous wollastonite in PP matrix was determined by scanning electron microscope (SEM). The results showed that the strength, toughness and flowability of the composite were simultaneously guaranteed by using three different types of PP resins, and the interfacial adhesion was improved greatly by adding the compatabilizer of PP-g-MAH, which increases the comprehensive properties of wollastonite/PP composite. The fibrous dispersion of wollastonite in PP matrix was achieved by using of side feeding and the weak-shear screw configuration, which reaches the good reinforcing effect.
Cyclodextrins in Textile Finishing: Fixation and Analysis
Authors: Bereck Attila
Published: January 2010

Following a short overview of application of cyclodextrins (CDs) in textile finishing
methods for the permanent fixation of CDs onto texiles and approaches to their quantitative analysis
are reviewed. A new analytical method, based on the inclusion complexation of ferrocene, and a
quantitative study, utilizing this method, on the covalent fixation, washing fastness and
formaldehyde release of CD-containing finishes are presented. Ferrocene complexation is proven by
Raman spectroscopy and by comparison with maltodextrin. Some of the finishing treatments
resulted high yields and permanence against washing. Hydroxypropyl-CD reduced formaldehyde
release and acted possibly as a formaldehyde scavenger. Using “low formaldehyde” crosslinkers ”
requirements easily met.
Application of Double Gate Ion Sensitive Field Effect Transistor for Detection of Fluid Flow Rate in Micro-Channel
Authors: Jiemsakul T. , Trithaveesak O. , Bunjongpru Win , Hruanun C. , Poyai Amporn , Nukeaw J.
Published: January 2010

In this work a micro flow sensor, using a double gate Ion Sensitive Field Effect Transistor (ISFET) and two metal electrodes, for fluid flow rate measurement in micro-channels were fabricated and demonstrated. By the channel fabrication the molds were patterned reversely on a silicon wafer using Deep Reactive Ion Etcher (DRIE). The double gate ISFET and two metal electrodes were placed on the mold in the distance 15 millimeters. The channels were formed using polydimethylsiloxane (PDMS) from the mold with the width 1000 and 2000 micrometer and the depth of 250 micrometer. After removing PDMS from the mold the channel was bonded with glass substrate by RF plasma technique. By the verification of flow sensors working range water and one mole of sodium nitrate solution were alternated in flow channel. The fluid flow rate were compared with the flow rate from weighing. It found from the comparison that the high deviation was found at low flow rate. Furthermore, the deviation depends also on the dimension of the flow channel.
Ultra-Thin Al2O3 Formation at Room Temperature
Authors: Limnonthakul Puenisara , Pokaipisit Artorn , Limsuwan Pichet
Published: January 2010

Ultra-thin Al films were deposited with different deposition times on silicon wafer and copper grid by dc magnetron sputtering. The sputtering power of 200 watt and Ar flow rate of 20 sccm were used to prepare the films. The deposition times were 40, 120 and 240 second, respectively. The deposited Al films were, then, left in the air under the humidity of 60% for 20 days. The crystal structure of ultra-thin Al films deposited on silicon wafer and copper grid were investigated by glazing x-ray diffraction (GXRD) and transmission electron microscopy (TEM), respectively. The XRD results show that after the ultra thin Al films were exposed to the air, the Al was oxidized and the Al2O3 was formed at room temperature. In addition, Al deposited for 120 and 240 second can form polycrystalline of -Al2O3 with preferred orientations of (110) and (311) planes. The TEM images show that the particle size of -Al2O3 was about 8.5 nm for deposited time of 120 second. Moreover, the spectroscopic ellipsometry (SE) data and simulation model of Bruggemann effective medium approximation (BEMA) was used to determine the volume fraction of Al2O3.
Gelatin/Hydroxyapatite Scaffolds: Studies on Adhesion, Growth and Differentiation of Mesenchymal Stem Cells
Authors: Vachiraroj Nuttapon , Damrongsakkul Siriporn , Kanokpanont Sorada
Published: January 2010

In this work, we developed a 3-dimensional bone tissue engineering scaffold from type B gelatin and hydroxyapatite. Two types of scaffolds, pure gelatin (pI~5) (Gel) and gelatin/hydroxyapatite (30/70 wt./wt.) (Gel/HA), were prepared from concentrated solutions (5% wt./wt.) using foaming/freeze drying method. The results SEM revealed the interconnected-homogeneous pores of Gel and Gel/HA were 121  119 and 148  83m, respectively. Hydroxyapatite improved mechanical property of the gelatin scaffolds, especially at dry state. Compressive modulus of Gel and Gel/HA scaffolds were at 118±21.68 and 510±109.08 kPa, respectively. The results on in vitro cells culture showed that Gel/HA scaffolds promoted attachment of rat’s mesenchymal stem cells (MSC) to a 1.23 folds higher than the Gel scaffolds. Population doubling time (PDT) of MSC on Gel and Gel/HA scaffolds were 51.16 and 54.89 hours, respectively. In term of osteogenic differentiation, Gel/HA scaffolds tended to enhance ALP activity and calcium content of MSC better than those of the Gel scaffold. Therefore the Gel/HA scaffolds had a potential to be applied in bone tissue engineering.
On-Chip Platinum Micro-Heater with Platinum Temperature Sensor for a Fully Integrated Disposable PCR Module
Authors: Sripumkhai W. , Lekwichai A. , Bunjongpru Win , Porntheeraphat S. , Tunhoo B. , Ratanaudomphisut E. , Kamsri T. , Hruanun C. , Poyai Amporn , Nukeaw J.
Published: January 2010

The on-chip platinum micro-heater prototypes for thermal cycling equipped with platinum temperature sensor are fabricated. The device has been designed, fabricated and characterized to explore the feasibility of the micro-heater for a fully integrated disposable lab-on-a-chip with the PCR module. The on-chip micro-heater demonstrates that the temperature transitions are shorter by comparison with the conventional PCR temperature routines.
Bimetallic Group 6 Tricarbonyls Triply-Bridged by Bis(phenylthio)alkane Bidentate Ligands
Authors: Asali Khalil J.
Published: January 2010

Reactions of the labile complex (Me3tach)M(CO)3 (Me3tach = 1,3,5-trimethyl-1,3,5-triazacyclohexane; M = W, Mo) with bis(phenylthio)alkanes ( = PhS(CH2)nSPh), (2:3 molar ratio) in CH2Cl2 as solvent (at 35 oC M = W, 0 oC M = Mo) afforded in good yields bimetallic tricarbonyl complexes triply- bridged by bis(phenylthio)alkanes of the type [M(CO)3]2(μ-PhS-(CH2)n-SPh)3 [n = 3 (a), 4 (b), 5 (c), 6 (d); M = W (1), Mo (2)]. These new triply-bridged complexes were characterized by 1H NMR, FT-IR and elemental analysis. Additionally, it has been observed that the thermodynamic stability of some of these new complexes in chlorinated hydrocarbons depends mainly on the nature of the metal center and varies in the order W >> Mo.
Mixed Matrix Membranes from Crosslinked Poly(vinyl alcohol)(PVA) Composited with Zeolite 4A Grafted with Poly(2-hydroxyethyl methacrylate)(zeolite-g-PHEMA)
Authors: Khoonsap Santi , Khansawai Paveena , Amnuaypanich Sittipong
Published: January 2010

The mixed matrix membranes were prepared from crosslinked PVA embedded with zeolite 4A that was grafted with PHEMA. The PHEMA was grafted onto the zeolite surface by first, attaching the vinyl-silane onto the zeolite surface and subsequently polymerizing HEMA monomer via the free-radical polymerization. The FT-IR spectroscopy confirmed the successful grafting of PHEMA on the zeolite. The grafting percentage determined by thermalgravimetry analysis (TG) was found to increase with the amount of HEMA monomer. The membrane swelling in water and pure acetone revealed the decreasing trend with increased the zeolite loading. Examined by DSC, the amount of non-freezing bound water decreased with increasing the zeolite in the membranes.
Effect of Compatibilizers on Mechanical Thermal and Morphology Properties of HDPE/TiO2 Nanocomposites
Authors: Wiriyanukul N. , Wacharawichanant S.
Published: January 2010

This work studies the effect of PE-g-MA compatibilizer on mechanical thermal and morphological properties of high density polyethylene (HDPE)/titanium dioxide (TiO2) nanocomposites. The HDPE/TiO2 nanocomposites with and without PE-g-MA compatibilizer were prepared by melt mixing technique in a twin screw extruder. The results found that Young's Modulus of HDPE/TiO2 nanocomposites increased with increasing TiO2 contents. The addition of PE-g-MA compatibilizer had no significant effect on the tensile strength and stress at break of HDPE/TiO2 nanocomposites. The decomposition temperatures of HDPE/TiO2 nanocomposites before and after adding PE-g-MA compatibilizer increased with increasing TiO2 contents. The dispersion of TiO2 nanoparticles in HDPE matrix was observed by scanning electron microscope (SEM). The dispersion of nanoparticles in HDPE matrix with PE-g-MA compatibilizer was relatively good, only a few aggregates exited.
Effect of Coloring Agents on Starch Properties: In Powder and Paste Form
Authors: Kongmuang S. , Phakdisirivichai N. , Detwattanadet N. , Samma N. , Anurakchanaphon D. , Choodam T.
Published: January 2010

The aim of this study was focusing on the excipients interaction especially between coloring agents and diluents. There were two coloring agents with different charges ; methylene blue(M) showing positive charge while amaranth(A) giving negative charge but all having same concentration of 0.1% w/w in each mixing batch. There are five types of starch using as diluents; arrowroot starch (W), rice starch (R), cassava starch (S), corn starch (C) and lesser yam starch (l). The physical properties of starch powder and paste (5%w/v) were evaluated as angle of repose and viscosity respectively. While the concentration of both coloring agents were determined by either UV spectroscopy or eye observation. The storage conditions of all samples were kept in both light and dark area for 7 weeks. It was found in powder form that C gave the most stable of M while R gave the worst for m in both light and dark condition. M showed less influences on flow properties of starches than a in a powder state. The flow of C with M gave the best results. The W paste was shown to be the most stable physical properties. M was suitable for S paste in a dark condition. While A was suitable for C, R and W paste in a light condition. The charges of coloring agents might not be a major influence on some physical properties of starch in both powder and paste form.
Effective Properties of Electro-Elastic Composites with Multi-Coating Inhomogeneities
Authors: Biscani Fabio , Koutsawa Yao , Belouettar Salim , Carrera Erasmo
Published: January 2010

This work presents a micromechanics-based model to investigate the effective thermo-electric properties of piezoelectric composite materials. The effective thermo-electric properties are derived by considering a multi-coated ellipsoidal inhomogeneity embedded in a host material in the framework of the generalized self-consistent method (GSCM). An incremental scheme, in which the reinforcements are incrementally put in the host material, is implemented. The validation of the micromechanical model is performed with experimental data. The model proposed has a wide range of applications and can be extended to other physical properties.
Carrier Design for Astaxanthin Delivery
Authors: Cheeveewattanagul Nopchulee , Jirasripongpun Kalyanee , Jirakanjanakit Nuananong , Wattanakaroon Wanida
Published: January 2010

Astaxanthin is a natural carotenoid pigment with powerful antioxidant capacity which has been reported for beneficial effects on human health to prevent cancers and anti-degenerative diseases. Bioavailability of astaxanthin is however limited due to insoluble and instable properties of its lipophilic nature. This study describes the cytotoxicity and astaxanthin delivery using a surfactant (tween 80) and penetration enhancers (methyl -cyclodextrin and liposome) to enhance astaxanthin bioavailability in human hepatocellular carcinoma cell line. Toxicity of tween 80 and methyl -cyclodextrin increased with concentration. Liposome did not alter cell viability relative to untreated controls, regardless of concentration tested. Cellular uptake among delivery vehicles was compared at 24 hours and was found to be higher than that of astaxanthin without a vehicle. The cellular uptake rate was highest when liposome was used as the delivery vehicle. This finding aids in the development of design criteria for vehicles for delivery of antioxidants to cells.
Effect of Sulphur Hexafluoride (SF6) Plasma on Hydrophobicity of Methylcellulose Film
Authors: Rachtanapun Pornchai , Wongchiaya P. , Boonyawan D.
Published: January 2010

Effect of plasma treatments (power, pressure and treatment time) on hydrophobicity (contact angle and water absorption time) and sorption isotherm of methylcellulose (MC) film using sulphur hexafluoride (SF6) were investigated. MC film specimens were precondition in desiccators containing silica gel at 25 ±2°C for 48 h. MC film specimens were plasma treated by an inductivity coupled plasma discharged (ICP) at 13.56 MHz with operating powers (25-75 W) and gas pressures (20-200 mTorr). The treatment times (10-300 second). Hydrophobicity of treated methylcellulose film outstandingly increased. The best plasma treatment condition was power 50 W and 100 mTorr. The treated MC film had higher contact angle and water absorption time than untreated sample at all operated treatment times; contact angle was increased up to 56-80°. These results were corresponding to sorption isotherm. The treated film was absorbed moisture higher than untreated film.
Studies on the Preparation and Gas Sensing Properties of SnO2 Nanostructures at Room Temperature
Authors: Noipa Kiattisak , Pukird Supakorn
Published: January 2010

The SnO2 nanostructures have been synthesized by carbon-assisted growth at 800 oC for 3 hours. Using high pure tin powder as the source materials. The synthesized products were investigated by stereo microscope, X-rays diffraction (XRD) and scanning electron microscopy (SEM). XRD patterns show that the prepared products are tetragonal-structures with the lattice constant a = 0.4718 nm and c = 0.3187 nm. SEM images indicate that SnO2 nanowires are about tens of micrometers in length, 80-100 nm in width. The diameter of SnO2 nanoparticles vary from 10 nm to 100 nm. The synthesized products are high sensitivity and fast response time to ethanol gas at room temperature.
Deformation of the Extracellular Matrix Due to Osmotic Pressure in Cartilaginous Tissues
Authors: Punantapong Boonyong
Published: January 2010

This study is to characterize and estimate preferential flow and solute transport in soft tissue. In soft tissues, large molecules such as proteoglycans trapped in the extracellular matrix generate high levels of osmotic pressure to counter balance external pressures. The semi-permeable matrix and fixed negative charges on these molecules serve to promote the swelling and collapse behaviour of cartilaginous tissues when there is an imbalance of molecular concentrations. At the same time, the collagen fibres were a network of stretch-resistant matrix, which prevents tissue from over-swelling and keeps tissue integrity. Therefore, a simplified mathematical model is proposed, and implemented in the finite element method. Analytic solutions for solute distribution in the extracellular matrix were derived by solving under loading conditions. The results were found that the estimate with field fluctuations led to the numerical results in most cases, and significant differences were only found under conditions of highly constrained deformation.
Effect of Annealing Ambient on Self-Cleaning Properties of TiO2 Films Prepared by Reactive DC Magnetron Sputtering
Authors: Pudwat Sayan , Rakkwamsuk Pattana , Dumrongrattana Supattanapong
Published: January 2010

Titanium dioxide (TiO2) films were prepared on glass substrates without external heating by DC magnetron reactive sputtering. Argon and oxygen were used as sputtering and reactive gases, respectively. Initially TiO2 films were produced under a constant discharge power of 300W, total operated pressure of 1.10 Pa, the Ar:O2 flow rate of 50:45 sccm and film thickness of 300 nm. After deposition, the films were annealed in air and in vacuum (8×10-1 Pa) at a temperature of 350 °C and an annealed time of 2 hours. Films structure, optical properties, photocatalytic activity (methylene blue degradation) and photo-induced hydrophilicity properties were mainly investigated to produce self-cleaning surface. Because of higher crystallinity of vacuum-annealed films lead to the highest MB degradation under UV irradiation. While, air-annealed films showed lower MB degradation than as-deposited films that could be affected of contamination on surface and defect from annealing. Vacuum-annealed films showed changes of water contact angle on the films surface higher than as-deposited films and air annealed- films.
Membranes Prepared from a Blend of Poly(acrylic Acid) and Natural Rubber-Graft-Poly(vinyl Alcohol) (PAA/NR-g-PVA)
Authors: Wongthep Wilairat , Ruksakulpiwat Chaiwat , Amnuaypanich Sittipong
Published: January 2010

The blend membranes from PAA and NR-graft-PVA were prepared. By introducing potassium persulfate (KPS) initiator, PVA can be chemically attached to the NR latex particles which was confirmed by FT-IR spectroscopy. Most of added-PVA was grafted on the NR latex particles as indicated by the almost-linear increasing of grafting percentage. The swelling of the PAA/NR-g-PVA blend membranes was performed in different concentrations of water-ethanol solutions. For the water concentration lesser than 30 vol.%, all membranes showed almost no-swelling but beyond 30 vol.% water, the degree of swelling revealed the substantial swelling with the degree of swelling increased as PAA content in the membrane increased.
Characterization of (Ti,Al)N Thin Film Coated by PVD Cathodic Arc Using TiAl Target
Authors: Chokwatvikul C. , Surinphong S. , Busabok C. , Termsuksawad P. , Larpkiattaworn Siriporn
Published: January 2010

Sintered TiAl alloy with composition of 50 at.% Al and 50at.% Ti are used as target in the PVD cathodic arc system to produce (Ti,Al)N film. The coating conditions are operated using substrate bias voltage and arc current bias of 100V and 70 A, respectively. In addition, the coating time was set at 1.30 h with thru different values of nitrogen gas pressures: 1, 1.5and 2 Pa. After coating the film was characterized for thickness, surface roughness, adhesion, morphology, and phase structure. It was found that phase structures, film thicknesses and adhesion of the films deposited from different nitrogen pressures are not significantly different. However, the micrographs showed that the film prepared by using 1.5 Pa of reactive N2 gas is smoother with less droplets than those film prepared at the other two pressures.
Investigation on Degradation of Methyl Parathion Using Visible Light in the Presence of Cr+3 and N-Doped TiO2
Authors: Senthilnathan J. , Philip Ligy
Published: January 2010

Nitrogen (N) and Chromium (Cr) doped TiO2 was prepared by sol-gel process. A clear shift in the onset light absorption from UV region (<380) to visible region (>500 nm) was observed for the N-doped samples. The XRD results revealed the decrease in particle size with increasing N content in the lattice of anatase TiO2. Nitrogen doping does not alter the phase of anatase TiO2. The SEM and TEM images of N-TiO2 showed that the particle size is in the range of 20-25nm. The chemical nature of N in the N-TiO2 was evolved through X-ray photoelectron spectroscopy. The presence of different types of N species have been observed corresponding to different oxidation states and the presence of Ti–N and O–Ti–N have been confirmed from the observed binding energy values. Photocatalytic decomposition of methyl parathion was carried out in the visible region and found that N-doped TiO2 showed better catalytic activity than Cr and Cr/N doped TiO2.
Acetophenone and Benzophenone Derivatives as Catalysts in Photodegradation of PE and PP Films
Authors: Manangan Thara , Shawaphun Sarinya , Wacharawichanant Sirirat
Published: January 2010

Due to their versatile functionalization, acetophenone and benzophenone derivatives as plastic additives were synthesized and blended into PE and PP to study rate of degradation under ultraviolet irradiation by monitoring carbonyl index, tensile strength and weight loss. The photolytic reactions of these ketones in benzene solution showed that acetophenone derivatives, especially 3-nitroacetopheone, underwent rapid degradation under the short-wave ultraviolet (254 nm) rather than in the black light (366 nm) while benzophenone derivatives showed small carbonyl index reduction. However, both groups of ketones, in hexane solution or in PE and PP films, primarily lowered the carbonyl index and rised up again except for the bromo derivatives. At 96 hrs of UV irradiation, the tensile strength of the acetophenone-blended PE film reduced only 20% while the tensile strength of the acetophenone-blended PP film decreased dramatically upto 90% and 95% for the benzophenone-blended PP.