bluuebunny/crossref_metadata_2025 huggingface dataset:
Ferroelectric and Mechanical Properties of PZT-PZN-PNN Ceramics
Authors: Nabunmee S. , Vittayakorn Naratip , Cann David P. , Rujijanagul Gobwute
Published: March 2009

Ceramics in the system 0.05(Pb(Zn1/3Nb2/3)O3-0.15Pb(Ni1/3Nb2/3)O3-0.8Pb(Zr1/2Ti1/2)O3 (0.05PZN-0.15PNN-0.8PZT) were synthesized via the columbite method. Ferroelectric properties of the samples prepared by different sintering conditions were investigated. The mechanical property of the ceramics was also determined. The best ferroelectric properties were observed for the sample sintered at 1250°C.
Formation of NaNbO3 Crystals in Dielectric Glass and Glass-Ceramics of a Na2O-Nb2O5-Al2O3-SiO2 System
Authors: Thongsaeng S. , Niyompan Anuson , Tipakontitikul Rungnapa , Pengpat Kamonpan
Published: March 2009

Dielectric glass and glass-ceramics were derived from Na2O-Nb2O5-Al2O3-SiO2 system. Small amount of TiO2 were also introduced into glass compositions to study crystallization behavior of the glass with present of this nucleating agent. Conventional melt-quenching technique was employed for a glass production and the selected bulk glass samples were subjected to the heat-treatment process at appropriate temperature. After six different glass compositions were produced, and by observation with necked eyes, all obtained glass samples are in light brown color and some samples were opaque due to crystallization took place during quenching. Phase identification through XRD patterns show that there were 3 phases, NaNbO3, NaNbO8 and a sodium aluminum silicate compound, found in those opaque glass samples. NaNbO3 is a predominant phase in all samples. Fortunately, clear transparent glass was obtained from the composition with no TiO2 addition. Heat treatment of this glass did not induce phase change, three aforementioned phases still present. Increasing heat treatment time promoted a higher of observed intensity of NaNbO3. But the NaNbO3 crystalline size was not significantly developed with time. The dielectric response of the NaNbO3 crystals in the glass-ceramics samples are influenced by presence of other crystalline phases.
Application of the PEGDE Modified Silk Fibroin Membrane to an Amperometric Glucose Biosensor
Authors: Moonsri P. , Watanesk S. , Watanesk R. , Niamsup H. , Cheng Q. , Deming R.L.
Published: March 2009

Stable silk fibroin (SF) membranes were prepared by modifying SF with polyethylene glycol diglycidyl ether (PEGDE) for use as enzyme immobilizing matrix. Morphology, structure, and water solubility of the modified silk fibroin (MSF) membrane were investigated. SEM images revealed greater porosity in the MSF membranes. IR spectra confirmed the predominant β-sheet conformation when the PEGDE was greater than 4%. In addition, the MSF membranes were highly insoluble within the pH range 4 10. An amperometric glucose biosensor was initially constructed using glucose oxidase (GOx) immobilized on the MSF membrane, coupled to a Prussian Blue (PB) deposited Au electrode. The response characteristics of the biosensors based on the GOx immobilized onto the 4% and 8% PEGDE modified SF membranes (4P-MSF and 8P-MSF) and the methanol treated SF membrane (MT-SF) were investigated. Amperometric measurements at the applied potential of 0.0 V demonstrated that the glucose biosensor based on the GOx immobilized onto the 4P-MSF membrane exhibited high sensitivity to glucose with a short response time, less than 3 s. Moreover, the stability of the biosensors based on the 4P-MSF membranes was better than those based on the MT-SF membrane after 2 weeks of storage in a phosphate buffer of pH 7.0 at 4 °C. These fundamental electroanalytical features of the sensor are therefore expected to be useful in biosensor application
Magnetic Nanoparticles as Smart Heating Mediator for Hyperthermia and Sorbent Regeneration
Authors: Phuc N.X. , Tuan N.A. , Thuan N.C. , Tuan V.A. , Hong L.V.
Published: March 2009

Titanium oxide (TiO2) nanopowders can be reproducibly formed by hydroxylation of titanium organic complexes. The crystallisation to anatase and rutile can be controlled by systematic calcination and a complex range of properties optimized for specific applications. Characterisation of the powders has been undertaken using advanced physical techniques. The morphology of the TiO2 powders is determined by solution concentration and precipitation phenomena, particularly temperature and stirring regime. However the fine powders have limitations in terms of processing flexibility particularly when nanostructured and organised features are desired, due to their fine particle structure and inability to be sintered without undergoing complete phase change. Anodising titanium metal can overcome these difficulties and under appropriate conditions semi-ordered nanotubes of TiO2 have been prepared. These can be heat treated to develop the phase of choice, anatase or rutile. A mechanism for the formation of the nanotubes has been proposed which is based on the linkage of pores developed in the anodized oxidation product. The pores are driven to into alignment by the applied potential and link up to form the tubular structures. A degree of control of the tube size and wall thickness is shown possible by control of applied voltage. The nanotubes have been investigated using SEM, TEM, XRD and Raman spectroscopy to elucidate the structure and postulate the formation mechanism.
Stability of Liquid Al Foams by Oxidised Al Powders
Authors: Asavavisithchai Seksak
Published: March 2009

The oxide content in Al powder has a significant effect on the expansion and stability of Al foams produced using a direct gas blowing method. The optimum level of oxide content is expected to be between 0.3 and 0.9 wt.% to enable large foam expansion.
Surfactant-Templated Synthesis of Modified Porous Clay Heterostructure (PCH)
Authors: Srithammaraj K. , Magaraphan Rathanawan , Manuspiya H.
Published: March 2009

Porous Clay Heterostructures (PCHs) have been prepared by the surfactant-directed assembly of mesostructured silica within the two-dimensional interlayer galleries of clays. The PCH is an interesting material to use as entrapping system such as ethylene scavenger, owing to its high surface area with uniform and specific pore size. In the present work, the PCH was synthesized within the galleries of Na-bentonite clay by the polymerization of tetraethoxysilane (TEOS) in the presence of surfactant micelles. In addition, a mesoporous clay with organic-inorganic hybrid (HPCH) is modified via co-condensation reaction of TEOS with methyltriethoxysilane (MTS) to enhance hydrophobicity of PCH material for entrapping system. According to pore characterization, PCHs have surface areas of 421-551 m2/g, an average pore diameter in the supermicropore to small mesopore range of 4.79-5.02 nm, and a pore volume of 0.57-0.66 cc/g while HPCHs have surface areas of 533-966 m2/g, an average pore diameter of 4.28-6.38 nm, and a pore volume of 0.42-0.77cc/g.
Effect of Reaction between Fe and Carbide Particles on Mechanical Properties of Fe-Base Composite
Authors: Chakthin S. , Poolthong Nuchthana , Tongsri Ruangdaj
Published: March 2009

Sintered Fe-5 wt. % carbide (SiC or TiC) composites have been prepared via a powder metallurgy (P/M) route. Two carbide particle sizes, < 20 µm and 20-32 µm, were mixed with Fe powder. The powder mixtures were compacted and sintered at 3 different temperatures, 1100, 1150 and 1200 °C. Microstructures of sintered Fe-5 wt. % SiC composites showed evidence of SiC decomposition. The decomposed Si and C atoms diffused into Fe particles resulting in formation of solid solution of Si and C in Fe during sintering. During cooling, the solid solution of C in Fe decomposed to pearlite structure (ferrite and cementite (Fe3C) lamellar structure). Microstructures of sintered Fe-5 wt. % TiC composites showed no evidence of TiC decomposition at the investigated sintering temperatures. Because of the reaction between SiC and Fe, tensile strength and hardness of the sintered Fe-SiC composites were higher than those of the sintered Fe. Experimental results showed that strength and hardness of the sintered Fe-SiC composites increased with increasing sintering temperature and with decreasing SiC particle size. In contrast, mechanical properties of the sintered Fe-TiC composites were inferior to those of the sintered Fe. The reason of poor mechanical properties may be attributed to poor bonding between Fe and TiC particles.
Copper Powder Extrusion: A Smart Processing for Energy and Environment Conservation
Authors: Wichianrak R. , Thavarungkul N. , Poolthong Nuchthana , Tongsri Ruangdaj
Published: March 2009

Cu powder extrusion developed in this work is aimed to be a pilot processing technique to plausibly replace conventional metal extrusion, which is higher in energy consumption and hence causes negative environment impact. In this study, both spherical- and irregular-shape Cu powders were used. 5 different binder formulae comprising low density polyethylene (LDPE); paraffin wax; and stearic acid of 25:70:5, 30:65:5, 35:60:5, 40:55:5 and 45:50:5 by weight were studied. Wettability between the binders and Cu powder of all formulae observed by naked eye appeared to be satisfactory. The binders were then mixed with 60% by volume of Cu powder. Rheological properties, observed using a capillary rheometer with 2 mm diameter orifice at 95°C, determined that the last 2 formulae gave sufficient green strength in the extrudate. However, only the latter binder formula gave extrudate with smooth surface. Downward extrusion with 45 cm distance from the die gave straight extrudates and no any distortion or warpage was found. Solvent debinding conditions using hexane at 40, 50 and 60°C were studied. The debinding at 50°C was the most effective in dissolving the binder and ensured that the Cu powder remained intact. The 15 cm-long Cu extrudates were sintered in H2 atmosphere at 1030°C for different times. Density and tensile strength of the sintered extrudates were determined.
Toughening of PZT Ceramics by In Situ Complex Structures
Authors: Thongmee N. , Watcharapasorn Anucha , Jiansirisomboon Sukanda
Published: March 2009

This research fabricated ceramics with formula (1-x)PZT - xBLT, when x = 0, 0.03, 0.05, 0.07, 0.10, 0.15 and 0.20 by a solid-state reaction method and sintered at a temperature of 1150 oC for 4 h with a heating/cooling rate of 5 oCmin-1. Phase analysis using XRD indicated the existence of PZT-based solid solutions with corresponding lattice distortion. SEM micrographs of ceramic surfaces showed a typical grain structure for PZT-rich phase, while a plate-like structure in BLT-rich phase was observed. PZT-rich ceramics possessed relatively high densities due to their more equiaxed grains with high packing capability compared with the ceramics with an addition of BLT. An addition of BLT generally decreased grain size of the ceramics. Mechanical properties such as hardness and fracture toughness could be enhanced significantly with small addition of complex structure BLT.
Sonocatalyzed Ammonothermal Preparation of Fine Lithium Niobate Powders
Authors: Rujiwatra A. , Thammajak N. , Chimupala Y. , Laoratanakul Pitak
Published: March 2009

The so-called sonocatalyzed ammonothermal technique has been developed for the preparation of lithium niobate fine powders from commercially as-received niobium pentoxide and lithium nitrate. The present work shows that the application of ultrasonic activation prior to the ammonothermal treatment can produce a single phase lithium niobate fine powder at a relatively low temperature of 220°C. The influences of Li-precursors, ammonia solution concentration, reaction temperature and time, as well as Li:Nb mole ratio - which is evidentially the most critical factor promoting a single phase formation - are discussed.
Novel Manufacturing Process for Tencel/Chitosan/Pectin Composite Dressing
Authors: Lin Chin Kai , Lou Ching Wen , Lu Chao Tsang , Huang Chao Chiung , Lin Jia Horng
Published: March 2009

The treatment for wound is a common issue in nursing procedure. Especially in serious wound, the treatment for wound usually spends many costs and time. Generally, wound dressing is used to protect the wound from bacterial infection in the intervening period between hospitalization and grafting. The pectin and chitosan are natural polymers that have biocompatibility and biodegradability, and pectin and chitosan can be easy obtainment and low cost. Tencel is a regenerated fiber. The Tencel fibers are biodegradable and hydrophilic, and have stable capability of dimension. Therefore, if the pectin and chitosan can be properly developed and combine with the tencel fabric for dressing use, the cost and time for wound treatment could be effective reduction. The absorbent cotton fibers were blended with the tencel fibers to create the cotton/Tencel nonwoven substance using nonwoven manufacturing technique. Chitosan will be electrospun on the Tencel nonwoven substance to create chitosan/Tencel composite nonwoven fabric. Furthermore, the surface structure of chitosan/Tencel composite nonwoven was observed by using scanning electron microscopy (SEM) to examine spinning ability of chitosan. Additionally, the pectin solution was blended with calcium chloride solution. Then pectin blended solution was coated on the optimal chitosan/Tencel composite nonwoven fabric by using mesh printing technique to prepare composite dressing. The result shown the Tencel/chitosan/pectin composite dressing has good capabilities of water absorbency and evaporative water loss. This study showed that a novel process for medical dressing was useful, and the composite dressing had an advantage property on wound healing and protection.
Manufacturing and Stab-Resisting Properties of Compound Fabric Reinforced Using Recycled Nonwoven Selvages
Authors: Chen Jin Mao , Hsieh J.C. , Lou Ching Wen , Hsing Wen Hao , Yang H.J. , Lin Jia Horng
Published: March 2009

Nowadays, the development of science and technology are rapidly, relatively, wastes brought more and more problems. Because the waste produced by the textile production accounts for 5% of total rubbish quantity, so how to reduce the pollution of the selvage wastes and how to effective treatment waste is the present primary task in the course of developing. This research is mainly to use two layers of the 7.0d polyester (PET) nonwoven as the base cloth of the upper strata and lower strata, and the selvage wastes of the PP are layered between them. The polyester nonwoven and selvage wastes combine by needle punching and thermal bonding than the nonwoven/ selvage wastes compound fabrics are formed. By this production, we can reduce waste quantity of selvage to achieve the environmental protection purpose, and increase the strength of the compound fabric. The results show when the weight of base cloth is 150 g/m2, the content of selvage waste in the compound fabric is 10%, temperature of thermal bonding is 220 °C, the liner velocity of the thermal compress roll is 0.5 m/min and the density of needle punching is 400 needles/cm2, the compound fabric has best mechanical properties. The stab resistance and the application of the compound fabric in geotextile are evaluated by test according to ASTM D4632 and ASTM D4533 standard.
Evaluation of Manufacturing Technology and Characterization of Composite Fabric for Stab Resistant Materials
Authors: Lin Chia Chang , Lou Ching Wen , Hsing Wen Hao , Ma W.H. , Lin Chin Mei , Lin Jia Horng
Published: March 2009

d more to their own safety, lead all kinds of personal protection apparatus to rapidly develop. This study designed and manufactured the stabbing resistant fabrics to prevent the pricking damage of human body. In this study, woven Kevlar fabric is laid between two layers of polyamide 6 fibrous webs that contain low-melt polyester fibers. The fibrous webs and woven fabric are bonded via needle punching and thermal bonding to generate a nonwoven/woven composite fabric that can be used as a substrate for artificial leather. The polyamide 6 staple fiber is the primary component of the nonwoven structure. The low-melt polyester fiber was added via thermal bonding to reinforce the composite fabric structure. The stab resistance of the composite fabric was reinforced by the woven Kevlar fabric. Because the bonding process alters the mechanical properties of the composite fabric, effects of bonding process conditions, such as needle punching density and thermal bonding temperature, on the mechanical properties and stab resistance of the composite fabric were investigated. The stab resistance of the composite fabric was assessed by stab resistance tests using the ASTM F1432 standard. Experimental results demonstrate that the optimal parameters obtained from sample which needle punching density is 200 needles/cm2
The Influence of Total and Oxygen Partial Pressures on Structure and Hydrophilic Property of TiO2 Thin Films Deposited by Reactive DC Magnetron Sputtering
Authors: Chaiyakun Surasing , Buranawong A. , Deelert T. , Witit-Anun N.
Published: March 2009

TiO2 thin films have been deposited by reactive DC magnetron sputtering technique to study the effect of total pressure and oxygen partial pressure on structure and hydrophilic properties. The crystal structure and hydrophilic property was measured by XRD and contact angle meter, respectively. The results showed that the films were composed of pure rutile and mixed of anatase/rutile structure dependent on the total pressure and oxygen partial pressure. It was found that all films can perform hydrophilic property. In case of high total pressure, the films showed superhydrophilic property, whereas the films deposited under various oxygen partial pressures with fixed total pressure were all films exhibit superhydrophilic property.
Composites Base on Geopolymer Matrices: Preliminary Fabrication, Mechanical Properties and Future Applications
Authors: Hung T.D. , Pernica D. , Kroisová Dora , Bortnovsky Oleg , Louda Petr , Rylichova Vladka
Published: March 2009

Geopolymer matrice Composites are fabricated at room temperature or thermoset in a simple autoclave. After approximately four hours of curing, composite materials exhibit excellent properties. Finding applications of geopolymeric composites in all fields of industry are the hot topics. This paper covers: (i) mechanical properties of fibers: carbon, Saint-Gobain Cemfil/CFV alkali resistance glass (various types), ARG-NEC (Nippon electric Columbia) alkali resistance glass, E-glass for pultrusion, AR glass for pultrusion were evaluated in accordance with Japanese Industrial Standard (JIS R 7601). (ii) properties of geopolymeric matrices: geopolymeric matrices are fabricated from various types of geopolymeric resins that were made at Research Institute of Inorganic Chemistry, Inc., Czech Republic and testing for mechanical properties, and by SEM for structure characterization. (iii) fabrication procedures of geopolymer matrix composites with carbon and other fiber reinforcements. (iv) results of mechanical testing of geopolymer composites, SEM for adhesion between the matrix and reinforcement, and (v) Results and discussion.
Effect of Annealing on the Structure and Dielectric Properties in PZT-PCoN Ceramics
Authors: Vittayakorn Naratip , Chaiyo N. , Muanghlua R. , Ruangphanit A. , Vittayakorn Wanwilai C.
Published: March 2009

he solid solution between the normal ferroelectric Pb(Zr1/2Ti1/2)O3 (PZT) and relaxor ferroelectric Pb(Co1/3Nb2/3)O3 (PCoN) was synthesized by the solid state reaction method. Sintered PZT-PCoN ceramics were annealed at temperatures ranging from 850 to 1,100°C for 4 h. X-ray diffraction patterns revealed changes of crystalline structure after annealing, which could be correlated to the accompanied changes in dielectric properties. Furthermore, significant improvements in the dielectric responses were observed in this system. After annealing, a huge increase of up to 200% occurred in the dielectric constants, especially near the temperature of maximum dielectric constant.
Light Scattering in Poly(Methyl Methacrylate) Hybrid Sheet Filled by Titanium Dioxide Nanocrystals Prepared by High Electric Field Assisted Spray Pyrolysis Process
Authors: Ksapabutr Bussarin , Anukoolwittaya P. , Panapoy M.
Published: March 2009

In this work, titanium dioxide (TiO2) nanocrystals were prepared via spray pyrolysis process under high electric field, and were used for tuning the light scattering properties of poly(methyl methacrylate) (PMMA) sheets by embedding their nanopowders in PMMA matrix. The effect of processing conditions such as precursor concentration and calcination temperature on morphology and particle size was investigated. The sprayed and calcined TiO2 nanopowders were characterized by XRD, SEM and TEM. The intensity of the light radiation for TiO2/PMMA hybrid sheets was measured using a LUX meter. It was suggested that the efficiency of TiO2 nanocrystals can be increased dramatically by controlling both the particle size and the morphology. For TiO2/PMMA nanocomposite hybrid sheets, the light scattering capability was found to be about 15 times higher than that of pristine PMMA sheets at the distance of 30 cm.
Synthesis of Coil-Like Shape CNTs by Thermal CVD Method
Authors: Pakdee U. , Suttisiri N. , Hoonnivathana Ekachai , Chiangga S.
Published: March 2009

The coil-like shape carbon nanotubes (CNTs) were synthesized on stainless steel substrates using acetylene gas (C2H2) at 750oC under pressure of 4110−× bar by thermal chemical vapor deposition (CVD) method. The formation of catalytic nanoparticles used hydrogen (H2) as the environment gas. The scanning electron microscope (SEM) image shown the average coil diameter of CNTs is 0.8µm and 0.1 nm for the average coil pitch of CNTs. The Raman spectrum shown the defect of CNTs and indicate that the carbon samples were tubes.
The Diamond Crystal Nucleation by Combustion Activation CVD
Authors: Wongprasert Y. , Muanghlua R. , Sato K.
Published: March 2009

This paper presents the diamond nucleation using combustion activation chemical vapor deposition (CACVD) by 0.95 volumetric ratio of O2 /C2H2 under atmospheric pressure. The main point of our work is to develop the CACVD technique for synthesize the semiconductor materials, which is developed for electronic devices application. The surface nucleation of substrate was studied by using surface pretreatment. The results of surface nucleation on mirror-silicon, polished silicon by diamond powder, silicon-dioxide (SiO2), and polished SiO2 by diamond powder, are significantly different. It can be concluded that the silicon-dioxide mask technique is useful for nucleated diamond protection whereas the polished silicon by diamond powder is suitable for nucleated diamond generation. These techniques are applied for the pattern fabrication.
Electronic Structure of Straight and T-Shape Singled-Wall Carbon Nanotube Junctions: A Molecular Quantum Mechanics Study
Authors: Udomvech A. , Kerdcharoen Teerakiat
Published: March 2009

In this paper, the straight and T-shape single-walled carbon nanotube intramolecular junction (SWCNT-IMJ) were studied theoretically. The geometries of topological defect can be constructed by fusing two nanotubes having different helicities and diameters. For straight IMJ, the armchair (5,5) and (8,8) nanotubes segments were fused with the zigzag (n,0) segment varying from (6,0) to (10,0). T-junctions were constructed by joining a zigzag (n,0) tube, varying from n = 5 to 10, onto a fixed zigzag (9,0) tube sidewall. These junctions are composed of one or more pentagon and heptagon rings, and mixed pentagon-heptagon pairs as defects in the perfect hexagonal lattice. The study shows that the occurrence of defects geometries on SWCNT-IMJ and T-shape structures depends on the variation of tube helicity and diameter of combining nanotubes. The HOMO-LUMO energy levels exhibit the even-odd “quantum size” oscillation. The decreasing energy gap depends on variation of tube helicity and diameter of carbon nanotube. This study can be helpful as a knowledge base in the field of carbon nanotube molecular electronics.
Structural Evolution in the Processing of Fe/ BaFe12O19 Nano Composite via Mechanical Alloying
Authors: Ataie Abolghasem , Nikkhah-Moshaie R.
Published: March 2009

Barium hexaferrite particles derived from sol-gel combustion method with a mean particle size of 160 nm and Fe particles with a mean particle size of 150 µm were mechanically alloyed using planetary ball mill. Phase constitution and EDS analysis of the products were investigated by XRD and SEM, respectively. Magnetic properties of samples were measured by VSM. Influence of the milling time and Fe content on the phase constitution of synthesized composites has been investigated. XRD results indicated that in sample with 90 and 50wt% Fe, the magnetic composite with enhanced magnetic properties, formed based on Fe phase while barium hexaferrite particles embedded within Fe particles. In sample with 90% Fe, the crystallite size of Fe reduced from 173 to 87 nm by increasing the milling time from 1 to 20 h; saturation magnetization of the 20 h milled sample was measured as 94.8 emu/g. Besides, in sample with 50wt% Fe, some FeO phase was detected which is probably due to the partial decomposition of hard magnetic phase during milling. Sample with 10wt% Fe showed completely different behavior and magnetite appeared as a major magnetic phase.
Relationships between Processing Parameters and Properties of PZT Ceramics
Authors: Puchmark C. , Rujijanagul Gobwute
Published: March 2009

In present work, lead zirconate titanate (PZT) ceramics, having the composition near morphotropic phase boundary were prepared by conventional mixed oxide method. The sintering process was performed at various sintering temperatures ranging from 1100 to 1300 oC. Relationships between phase and sintering temperature, and phase and structure were reported. An increase sintering temperature affected the increase in grain size. The grain growth rate was found to have a linear fit with the phenomenological kinetic grain growth equation. Tetragonal relative fraction increased with increasing sintering temperature. In addition, dielectric constant at dielectric peak increased with increasing grain size which consistent with the trend of tetragonality.
Effects of Gold Nanoparticles on the Fabrication of Red Colored High Refractive Index Lead Glass
Authors: Dararutana Pisutti , Dutchaneephet J. , Chetanachan Prukswan , Wathanakul P. , Sirikulrat Narin
Published: March 2009

Red colored gold ruby glass used for decorations in ancient times was actually gold nanotechnology at work by the addition of gold particles into molten lead glass. Most of high refractive index glasses are based on lead-bearing silicate glass. High refractive index lead glasses (HRLG) made from local sands and lead oxide were successfully fabricated both in laboratory and larger scales. In this study, gold metal was doped into the lead glass mixtures. Morphology of the prepared lead glass was observed using SEM and compared with that of the red colored Ancient Thai Glass (ATG). It was found that the fabricated red colored HRLG yielded similar color and clarity to the red colored ATG. From electron micrographs, the presence of gold in lead glass was in the form of nanoparticles. The optical properties of the glasses were also examined.
CuO Nanostructure by Oxidization of Copper Thin Films
Authors: Raksa Phathaitep , Gardchareon A. , Mangkorntong N. , Choopun Supab
Published: March 2009

CuO nanostructures were synthesized by oxidizing copper thin films. The copper thin film was grown on alumina substrates by evaporation copper powder at pressure of 0.04 mtorr. The copper thin films were then oxidized 800, and 900oC for 12, 24 and 48 hr, respectively. The obtained CuO nanostructures were investigated by Energy Dispersive Spectroscopy (EDS), Field Emission Scanning Electron Microscope (FE-SEM) image, and X-Ray Diffraction (XRD). The diameter of CuO nanostructure is around 100-600 nanometers and it is depends on oxidation reaction time and temperature. These CuO nanostructures have a potential application for nanodevices such as nano gas sensor or dye-sensitized solar cells.
Chemical Synthesis and Characterization of ZnTiO3 Powder Prepared by the Coprecipitation Oxalate Method
Authors: Pookmanee Pusit , Yotasing J. , Phanichphant Sukon
Published: March 2009

Zinc titanate (ZnTiO3) powder was prepared by the coprecipitation oxalate method. Zinc nitrate and titanium (IV) isopropoxide were used as the starting materials with the mole ratio of Zn:Ti was 1:1. Oxalic acid and ammonium hydroxide were added into the mixed solution. Precipitated powder was obtained after the final pH of solution was 5. The fined powder was washed with deionized water, filtered, dried at 100 oC for 2h, and followed by the calcination at 500, 700 and 900 oC for 2h. The phase of ZnTiO3 powder was studied by X-ray diffraction (XRD). The morphology was characterized by scanning electron microscopy (SEM). Hexagonal and cubic phase of ZnTiO3 powder were obtained after calcination at 900 oC. The particle size of ZnTiO3 powder was in the range of 0.1-0.5 µm with irregular in shape and agglomerated. The chemical
Synthesis and Characterization of Zinc Oxide Nanocrystals by Solid-State and Solvothermal Techniques
Authors: Satienpattanakoon C. , Yiamsawas D. , Kangwansupamonkon Wiyong , Nuisin R.
Published: March 2009

The nanostructural zinc oxide (ZnO) particles have been synthesized by two techniques, solid-state reaction and solvothermal method. The solid-state reaction method, the ZnO nanoparticles were carried out by reacting zinc acetate with sodium hydroxide in sodium dodecyl sulfate (SDS) and beta-cyclodextrin (b-CD). The effects of reaction condition on the nanocrystal morphology were investigated. The physical properties of ZnO were characterized using X-ray diffraction technique and transmission electron microscopy. The results showed that the obtained ZnO nanorods were in the wurtzite structure with various sizes of single crystals. FT-IR analysis also confirmed the binding of SDS with ZnO nanorods. For the solvothermal technique, ZnO nanostructures with various morphologies were synthesized from the treatment of zinc acetate at 80°C with the selected polymeric surfactant, poly(vinyl pyrrolidone) (PVP), in aqueous solution and ethylene glycol. The results showed that the selected surfactant and solvent play a different role in controlling the morphologies of the ZnO nanocrystals. The ZnO nanorods and nanoparticles were successfully obtained. The XRD result revealed that the ZnO is in the wurtzite structure with the particle size in range of 270-1300 nm. The optical properties of the samples were also studied via UV-vis spectrophotometer.
Modification of Thai Silk Fibroin Scaffolds by Gelatin Conjugation for Tissue Engineering
Authors: Chamchongkaset J. , Kanokpanont Sorada , Kaplan David L. , Damrongsakkul Siriporn
Published: March 2009

Silk has been used commercially as biomedical sutures for decades. Recently silk fibroin, especially from Bombyx mori silkworm, has been explored for many tissue engineering applications such as bone and cartilage due to its impressive biological compatibility and mechanical properties. In Thailand, Thai native silkworms have been long cultivated. Distinct characteristics of cocoon Thai silk are its yellow color and coarse filament. There is more sericin in Thai silk than in other Bombyx mori silks. These characteristics provide Thai silk a unique texture for textile industry. It is therefore the aim of this study to develop three-dimensional silk fibroin-based scaffolds from Thai yellow cocoon “Nangnoi-Srisaket” of Bombyx mori silkworms using salt-leaching method. To enhance the biological properties, type A gelatin, the denature form of collagen having good biocompactibility, was used to conjugate with silk fibroin scaffolds. The pore size of salt-leached silk fibroin scaffold structure represented the size of salt crystals used (600-710µm). After gelatin conjugation, gelatin was partly formed fibers inside the pores of silk fibroin scaffolds resulting in fiber-like structure with highly interconnection. Gelatin conjugation enhanced the compressive modulus of silk fibroin scaffolds by 93%. The results on in vitro culture using mouse osteoblast-like cells (MC3T3-E1) showed that gelatin conjugation could promote the cell proliferation in silk fibroin scaffolds. Moreover, the observed morphology of cells proliferated inside the scaffold after 14 days of culture showed the larger spreading area of cells on conjugated gelatin/silk fibroin scaffolds, compared to round-shaped cells on silk fibroin scaffolds. The results implied that Thai silk fibroin looked promising to be applied in tissue engineering and gelatin conjugation on Thai silk fibroin scaffolds could enhance the biological properties of scaffolds.
Substitution of Iron in Preparation of Enhanced Thermal Property and Bioactivity of Hydroxyapatite
Authors: Meejoo S. , Pon-On W. , Charnchai S. , Amornsakchai T.
Published: March 2009

Incorporation of Iron into hydroxyapatite (HAp) has generated a novel material for which their properties differ from those of conventional HAp. Although XRD indicated that the as-prepared iron-substituted hydroxyapatite (HApFe) is of a single crystalline phase similar to that of HAp, we found that carbonate ions can incorporate in the HApFe structure 3 times better than in HAp. As results, HApFe possesses the Vickers microhardness about 1.5 times higher than that of HAp. Thermal behaviors and bioactivity of HApFe are discussed in comparison to those of HAp. Various experimental methods have been employed in this work including powder XRD, IR, SEM, DSC/TGA and Vickers Hardness testing.
Processing, Mechanical Property Development and In Vitro Hydrolytic Degradation Studies of a Poly(L-Lactide-co-ε-Caprolactone) Monofilament Fibre for Potential Use as an Absorbable Surgical Suture
Authors: Chooprayoon P. , Siripitayananon J. , Molloy Robert , Bunkird S. , Soywongsa T. , Tariyawong A.
Published: March 2009

The bulk ring-opening copolymerisation of L-lactide (LL) and ε-caprolactone (CL) with an initial comonomer feed ratio of LL:CL = 75:25 mol % was carried out using stannous acetate as the initiator at 120 oC for 48 hrs. The copolymer was characterised by GPC, DSC and TGA. Due to its ability to biodegrade in the human body, this type of copolymer has potential for use as an absorbable surgical suture. The copolymer obtained was melt spun at 153 oC using a small-scale melt-spinning apparatus and extruded into ice-cooled water to produce an as-spun monofilament fibre which was largely if not completely amorphous. Alternate off-line hot-drawing and annealing (3 cycles) was carried out in order to develop the fibre’s oriented semi-crystalline morphology. To complete the processing operation, thermal treatment was necessary to stabilize the fibre morphology. It was found that fixed annealing at 60 oC followed by free annealing at 60 oC stabilized the fibre morphology as a result of molecular relaxation. In vitro hydrolytic degradation studied in a phosphate buffer saline (PBS) solution of pH 7.4 at 37.0 ± 0.1 oC indicated that, after 6 weeks immersion in the buffer, the fibre’s tensile strength decreased by approximately 50% whereas a commercial ‘PDS’ suture of similar size lost its strength completely after only 4 weeks.
Zwitterionic and Charge-Balanced Polyampholyte Copolymer Hydrogels
Authors: Campbell D. , Tighe B.J.
Published: March 2009

Zwitterionic copolymers were synthesised from N,N-dimethyl-N-(2-acryloylethyl)-N-(3-sulfopropyl) ammonium betaine (SPDA) and 2-hydroxyethyl methacrylate (HEMA) produce a series of polyzwitterion hydrogels. For the synthesis of the charge-balanced copolymer hydrogels, two cationic monomers were selected: 2-(diethylamino) ethyl methacrylate (DMAEMA) and 3-(dimethylamino) propyl methacrylamide (DMAPMA), and an anionic monomer; 2-acrylamido-2-methylpropane sulphonic acid (AMPS). Two series of charge-balanced copolymers were synthesized from stoichiometrically equivalent ratios of DMAEMA or DMAPMA and AMPS with HEMA as a termonomer. All synthesized copolymers produced clear and cohesive hydrogels. The zwitterionic and charge-balanced copolymers displayed similar equilibrium water contents together with similar mechanical and surface energy properties. The swelling of the zwitterionic and the charge-balanced copolymers shows some features of antipolyelectrolyte behavior.
Morphology of Electrospun Mats of Soy Protein Isolate and its Blend
Authors: Phiriyawirut M. , Rodchanacheewa N. , Nensiri N. , Supaphol Pitt
Published: March 2009

Electrospinning has been recognized as an efficient technique for the forming of polymer nanofibers. In this project interest fabricated Soy Protein Isolate (SPI) nanofibers by electrospinning with different supply voltages, positive and negative charge. SPI was dissolved in 80%-95% w/w acetic acid solution and 80%-90% w/w formic acid solution. Only droplet formation of SPI were found instead of fibril formation, and the droplet morphology of SPI is depended on supply voltage, and type of solvent. SPI droplets from the negative supply voltage have smaller and more nodular than droplets from positive supply voltage. Formic acid SPI solution gives smaller size of droplet and more nodular than acetic acid SPI solution. In order to forming SPI nanofibers, zein/SPI blend were performed. The zein/SPI blend was studied at difference blending ratio. The 95/5 Zein/SPI was found to be the best blend composition for electrospun fiber. In addition, the effects of electrostatic distance and electrostatic voltage on electrospun fiber were also investigated. Increasing electrostatic distance or increasing voltage, smaller size of fiber was obtained.
Improved Electrical Conducting Wires for SOFCs
Authors: Masomtob M. , Wongtida K. , Charoensuk J. , Charojrochkul S.
Published: March 2009

Solid Oxide Fuel Cells (SOFCs) have attracted a number of researchers due to their efficiency as alternative energy devices. Studies have been conducted to investigate different components of the SOFCs to improve the performances. Current collecting wires are the components which have affected the overall performance. Since SOFCs are normally operated in the temperature range of 700-1000 °C in dual atmospheres, the wiring material must be able to function at this condition. Currently, the material used to make the wires is platinum because of its high electrical conductivity, high melting point and oxidation resistant. However, platinum is expensive, especially for the practical operation of SOFCs. Silver could be an alternative choice due to its very high electrical conductivity. Nevertheless, the melting point of silver is rather low (900-960 °C). In our study, a modified silver current collecting wire has been used in the temperature range of 100-1000 °C. Their conductivity curves have demonstrated higher performances in comparison with the systems employing Pt and gold wires. In addition, the cost is reduced approximately 800-1000 times from that of the traditional material used.
Magnetic Properties of Mn Doped NiO
Authors: Swatsitang Ekaphan , Pimsawat A.
Published: March 2009

ABINIT program package based on Density Functional Theory (DFT) within the Generalized Gradient Approximation (GGA) and plane wave basis set are used to calculate the magnetic properties of Mn doped NiO. It was found that the magnetic properties of Mn doped NiO were changed from anti-ferromagnetic (pure NiO) to ferromagnetism. Increasing the concentrations of Mn, the magnetization of Mn doped NiO were increased (Ni31MnO32 = 66.69 µB, Ni30Mn2O32 = 69.59 µB and Ni29Mn3O32 = 72.42 µB).
Effect of Bi2O3 Content on the Properties of Bi2O3-BaO-B2O3 Glass System
Authors: Kaewkhao Jakrapong , Pokaipisit Artorn , Chewpraditkul Weerapong
Published: March 2009

Glasses with composition xBi2O3:(60-x)BaO:40B2O3 with 10£x£50 (in mol%) have been prepared using the normal melt-quench technique. The optical absorption spectra of the glasses have been recorded in the wavelength range 400-700 nm. The fundamental absorption edge has been identified from the optical absorption spectra. The values of optical band gap are decreased with the addition of Bi2O3. The density and molar volume studies indicated that Bi2O3 in these glasses is acting partly as network modifier and partly as network former.Values of the theoretical optical basicity are also reported and discuss in term of oxide ion polarizability.
Influence of Substrate Temperature on Some Properties of Close-Spacing Thermally Evaporated CdTe Thin Films
Authors: Gaewdang Thitinai , Wongcharoen N. , Siribuddhaiwon P. , Promros N.
Published: March 2009

CdTe thin films with different substrate temperatures have been deposited by thermal evaporation method on glass substrate in vacuum chamber having low pressure about 3.0x10-5 mbar. According to XRD analysis, CdTe thin films are polycrystalline belonging to cubic structure with preferential orientation of (111) plane. The strongest peak intensity of XRD is observed in the film prepared with substrate temperature of 150°C. Band gap and band tail values of the as-deposited films were evaluated from the optical transmission spectra. The lowest dark sheet resistance value was obtained from the film prepared with substrate temperature of 150°C as well. Regarding to our experimental results, it may be indicated that the 150°C substrate temperature is the most suitable condition in preparing CdTe thin films for solar cell applications.
Effect of Al2O3 Addition on Dielectric, Piezoelectric and Ferroelectric Properties of 0.2Pb(Zn1/3Nb2/3)O3–0.8Pb(Zr1/2Ti1/2)O3 Ceramics
Authors: Ngamjarurojana Athipong , Ananta Supon , Yimnirun Rattikorn
Published: March 2009

The structure and electrical properties of Al2O3-doped 0.2Pb(Zn1/3Nb2/3)O3-0.8Pb(Zr1/2Ti1/2)O3 ceramic, which is the morphotropic phase boundary composition of the PZN-PZT system, were investigated. The addition of Al2O3 content transformed the crystal structure rom coexisting with rhombohedral to purely tetragonal structure. Furthermore, addition of Al2O3 decreased r, d33 and kp, but increased Curie temperature and enhanced the mechanical quality factor. inally, the P–E and s-E loops demonstrated decreased Pr, Ec and strain level with addition of Al2O3
Application of Artificial Neural Network to Calculate Curie Temperature of Ferromagnetic Materials
Authors: Laosiritaworn Wimalin S.
Published: March 2009

Ferromagnetic materials are now interested by researchers as they have applications in various industries. Due to the complexity of the materials, an important contribution to enhance the technological development has come from the theoretical and simulation studies especially from the Monte Carlo simulation. Nevertheless, the Monte Carlo is often limited in its performance because the computational limitations, such as the simulated system sizes and simulation times. These limitations also put a constraint on the simulation time which caps the numerical accuracy. The artificial neural network is used in this study in cooperating with the Monte Carlo simulation. The aim is to investigate the possibility in obtaining the Curie temperature of ferromagnetic Ising spin in a fine scale without an intense computational required. From the results, the extracted Curie temperature is found to agree well with those from the exact theoretical analysis which verifies the artificial neural network to be a very useful technique.
Preparation and Properties of Thermal Insulation Latex Paint for Exterior Wall Based on Defibred Sepiolite and Hollow Glass Microspheres
Authors: Wang Fei , Liang Jin Sheng , Tang Qing Guo , Wang Na , Li Li Wei
Published: March 2009

Thermal insulating latex paint for exterior wall was prepared by water as dispersing media, polyacrylic emulsion as basic material, defibered sepiolite and hollow glass microspheres as main functional additives. The thermal insulation effect and mechanism were studied by thermal insulation effect testing device and visible light reflectance tester. The results show that the optimum contents of functional additives are as follows: 8% defibred sepiolite fibers, 6% hollow glass microspheres. The coating could arrest heat transmission and reflect visible light effectively.
Research on Potential Control Flotation of Molybdenite
Authors: Yin Wan Zhong , Zhang Li Rong , Ding Ya Zhuo
Published: March 2009

In this paper, potential control flotation of molybdenite has been investigated which focus on the effect of pulp potential on flotation performance. Optimum flotation conditions of molybdenite are determined through tests: optimum pulp potential is 190mv~300mv, dosage of sodium sulfide is 6kg/t.The potential control flotation does not use sodium silicate which solved the problem of tailing settlement difficulties. The mechanism of potential control flotation shows that S0 is the main factor that achieves potential control flotation of molybdenite.
Surface Encapsulation of Nano-CaCO3 Particle by In Situ Emulsion Polymerization
Authors: Yang Ming Shan , Quan Ying
Published: March 2009

The nano-CaCO3/polyacrylate core-shell inorganic-organic complex nano-particles were prepared by in situ emulsion polymerization based on fresh slush pulp of calcium carbonate (CaCO3) nanoparticles in this paper. The dispersion and encapsulation of nanoparticles were investigated by transmission electron microscopy (TEM) and electron spectroscopy for chemical analysis(ESCA). The results showed that in the presence of nano-CaCO3 particles, the in situ emulsion polymerization of acrylates was carried out smoothly, and polyacrylates successfully encapsulated on the surface of nano-CaCO3.
Synthesis and Characterization of LiFePO4 / PPy Composite Powders
Authors: Ren Xiang Zhong , Li Xi , Zhang Pei Xin , Liu Jian Hong , Zhang Qian Ling , Luo Zhong Kuang
Published: March 2009

A series of lithium iron phosphate /polypyrrole (LiFePO4/PPy) composite powders were synthesized by chemical oxidation method with different doping agent and oxidation agent. The composite powders were characterized by scanning electron microscopy (SEM), Fourier Transform Infrared Spectrum (FTIR), and X-ray diffraction (XRD). The results showed that the composite powders composed of PPy and LiFePO4. And the doping of polypyrrole in LiFePO4 could weaken the XRD intensity of LiFePO4 , but could not destroy its crystallization. With the increase of pyrrole in LiFePO4/ PPy composite powders, the polypyrrole on the surface of LiFePO4 increased and dispersed more homogeneously. Thermogravimetric analysis (TGA) data indicated the heat-stability of LiFePO4/PPy was very good that the composite powders would not oxidate till 300°C in the air flow.
The Effect of Posterior Disposal Process on Gel Viscosity of Montmorillonite/Octadecyl Trimethy Ammonium Chloride Complexes
Authors: Qiu Jun , Wang Gui Fang , Liu Yu Qin , Lu Xian Jun , Sun Li Jun
Published: March 2009

Thixotropic gel can be formed in the organic solvents is one of the most important application characteristics of montmorillonite/octadecyl trimethy ammonium chloride complexes. The key factor influencing the formation of gel is the preparation technology, and the posterior disposal process is also an important affecting factor which should be paid more attention to. In the paper, the effects of washing, drying temperature, grind size, activators and the polarity of solvents on the gel viscosity of montmorillonite/octadecyl trimethy ammonium chloride complexes were systematically studied. The research shows that fully washing can elute the octadecyl trimethy ammonium chloride ions or molecula adsorbed on the layer and the edge of montmorillonite crystal, and improve viscosity of gel formed by the complexes. Controlling the drying temperature at the range of 90－100°C and ensuring the complexes with a little interlayer water are favorable for the gel formation of the complexes. When the granularity of the complexes is less than 0.074mm, particles in solvents can fully produce solvation action, solvent swells and strips, and then form the thixotropic organic gel. Using the 95% ethanol as the activator, when its dosage is 5 wt%, its activation effect is better. The stronger the polarity of the dispersing solvent is, the more favorable the formation of the organic gel with higher viscosity is.