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Chulalongkorn University

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Full-Text Articles in Materials Science and Engineering

Exergetic And Thermoeconomic Analyses Of The Rice-Husk Power Plant In Thailand, P Peerapong, B Limmeechokchai Dec 2009

Exergetic And Thermoeconomic Analyses Of The Rice-Husk Power Plant In Thailand, P Peerapong, B Limmeechokchai

Journal of Metals, Materials and Minerals

The purpose of this study is to analyze a rice husk power plant, and consider the efficiency of the power plant through both the first law and the second law of thermodynamics. The energetic and exergetic performance criteria such as thermal efficiency, exergy efficiency, and exergy loss have been found to be useful methods in design, evaluation, optimization and improvement of thermal power plants. The exergetic efficiency of a power plant shows that the boiler is the major component contributing to total loss, with its exergetic efficiency of 30%, while the steam turbine has the exergetic efficiency of 76%. The …

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Ziegler-Natta Catalyst With High Activity And Good Hydrogen Response, L Sinthusai, W Trakarnpruk, R Strauss Dec 2009

Ziegler-Natta Catalyst With High Activity And Good Hydrogen Response, L Sinthusai, W Trakarnpruk, R Strauss

Journal of Metals, Materials and Minerals

Ziegler-Natta catalysts were prepared from chemical reaction route comprising of steps of 1) magnesium complex formation between butyloctyl magnesium and 2-ethyl-1-hexanol, 2) MgCl2 support preparation from the reaction between the magnesium complex and TiCl4 as chlorinating agent and 3) titanation with TiCl4. The catalysts were used for ethylene polymerization using triethylaluminum as a cocatalyst. Effects influencing properties of catalysts and polymerization performance were investigated: triethylaluminum/Mg molar ratio, Ti/Mg molar ratio, addition of electron donor and aging step. Results show that addition of ethylbenzoate as an electron donor resulted in decreased catalytic activity. However it was found that catalytic stability under …

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Synthesis And Characterization Of Sio2 Nanowires Prepared From Rice Husk Ash, S Pukird, P Chamninok, S Samran, P Kasian, K Noipa, L Chow Dec 2009

Synthesis And Characterization Of Sio2 Nanowires Prepared From Rice Husk Ash, S Pukird, P Chamninok, S Samran, P Kasian, K Noipa, L Chow

Journal of Metals, Materials and Minerals

SiO2 nanowires were synthesized by thermal evaporation of rice husk ash and coconut shell charcoal with the ratio of 1:2 by weight heated at a temperature of 1,350ο C in atmosphere of nitrogen for 1 hour. The scanning electron microscope and X-rays diffraction instrument are used to characterize the SiO2 nanowires. The SiO2 nanowires synthesized have diameters varying from 40 nm to 200 nm while the lengths were a few micrometers.

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Utilization Of Rice Husk To Synthesize High-Performance Phosphors, L Xiong, K Saito, S Wada, E H. Sekiya Dec 2009

Utilization Of Rice Husk To Synthesize High-Performance Phosphors, L Xiong, K Saito, S Wada, E H. Sekiya

Journal of Metals, Materials and Minerals

Rice husk (RH) has high C and Si contents, so it can be used not only as a fuel candidate, but also as a low-cost Si source for synthesizing high-performance products. In the present work, we proposed a low-cost route to synthesize high-performance silicate phosphors with RH. RH was burned either as received or as pretreated by HCl washing. The resulting ashes were, respectively, utilized to react with other raw materials at high temperatures to form silicate phosphors. The high-temperature solid-state reaction process was optimized by varying either the temperature or the holding time. The crystallographic and fluorescent properties of …

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Preparation Of Silica Gel From Rice Husk Ash Using Microwave Heating, S Rungrodnimitchai, W Phokhanusai, N Sungkhaho Dec 2009

Preparation Of Silica Gel From Rice Husk Ash Using Microwave Heating, S Rungrodnimitchai, W Phokhanusai, N Sungkhaho

Journal of Metals, Materials and Minerals

The purpose of this research is to separate silica gel from rice husk ash by microwave heating. The experiments were performed by heating rice husk ash in sodium hydroxide solution with various concentrations in microwave oven for 5 or 10 minutes. The obtained sodium silicate was neutralized to give silica gel. The best condition for silica gel production was the reaction with 2.0 M sodium hydroxide at microwave power of 800 W for 10 minutes. The ability of silica gel as desiccant was investigated by adsorption test. The results showed that silica gel prepared by low concentration of sodium hydroxide …

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Utilization Of Silica In Rice Hulls As Raw Materials For Silicon Semiconductors, T Okutani Dec 2009

Utilization Of Silica In Rice Hulls As Raw Materials For Silicon Semiconductors, T Okutani

Journal of Metals, Materials and Minerals

Highly pure silicon and silicon compounds are required in high technology products such as semiconductors and solar cells. Rice hulls consist of 71 to 87wt% organic components such as cellulose and 13 to 29wt% inorganic components. In rice hulls, 87 to 97wt% of the inorganic components are silica (SiO2). Rice plants absorb water-soluble siliceous ions via the roots. These ions are transported to stems, leaves and rice hulls by sap flow. In rice hulls, siliceous ions accumulate at the cuticle outside of the epidermis. The production of pure silicon compound (SiCl4) and of silicon metal as the starting material for …

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Pozzolanic Activity Of Rice Husk Ash: Comparison Of Various Electrical Methods, S Wansom, S Janjaturaphan, S Sinthupinyo Dec 2009

Pozzolanic Activity Of Rice Husk Ash: Comparison Of Various Electrical Methods, S Wansom, S Janjaturaphan, S Sinthupinyo

Journal of Metals, Materials and Minerals

The great abundance of rice husk ash (RHA) as low-cost agricultural waste in Thailand makes it the most suitable material for cement-based applications. However, the use of RHA as a supplementary cementitious material (SCM) is not yet widespread in Thailand due to the poor pozzolanic activity of most agricultural RHA. Most RHA is incinerated at too high temperatures (usually in excess of 1000ºC) or under uncontrolled conditions as biomass fuel. This reduces the amount of amorphous SiO2 and hence worsens the pozzolanic activity of the resulting RHA. To enhance the use of RHA as an SCM in Thailand, a proper …

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Synthesis And Characterization Of Silicon-Silicon Carbide Composites From Rice Husk Ash Via Self-Propagating High Temperature Synthesis, S Niyomwas Dec 2009

Synthesis And Characterization Of Silicon-Silicon Carbide Composites From Rice Husk Ash Via Self-Propagating High Temperature Synthesis, S Niyomwas

Journal of Metals, Materials and Minerals

Silicon-Silicon Carbide (Si-SiC) composites were synthesized by self-propagating high temperature synthesis (SHS) from a powder mixture of rice husk ash (RHA)-C-Mg. The reaction was carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The comparison of silica from RHA and commercial sources in the precursor mixture on the Si-SiC conversion has investigated using X-ray diffraction and scanning electron microscope technique. The as-synthesized products of Si-SiC-MgO powders were leached with 0.1M HCl acid solution to obtain the …

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Utilization Of Rice Husk Ash Silica In Controlled Releasing Application, P Prawingwong, C Chaiya, P Reubroycharoen, C Samart Dec 2009

Utilization Of Rice Husk Ash Silica In Controlled Releasing Application, P Prawingwong, C Chaiya, P Reubroycharoen, C Samart

Journal of Metals, Materials and Minerals

Mesoporous silica was produced by sol-gel technique using rice husk ash as a silica source which was applied in the drug delivery system. The drug releasing behavior was studied in phosphate buffer using indigo carmine as a drug model. The textural properties of mesoporous silica were characterized and considered with the result of the releasing study. The pore volume and silanol group on the surface of mesoporous silica affected the releasing behavior. The larger pore volume could contain the larger amount of drug which showed fast release. The effect of the silanol group presented an interaction between the drug molecule …

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Preparation And Characterization Of Silicon From Rice Hulls, E Swatsitang, M Krochai Dec 2009

Preparation And Characterization Of Silicon From Rice Hulls, E Swatsitang, M Krochai

Journal of Metals, Materials and Minerals

High purity silica can be prepared by reflux raw rice hulls in 1 N HCl for 45 minutes first, then pyrolyzed at 650°C for 3 hours in O2 atmosphere. The obtained white ash was examined by XRD showing a broad peak of amorphous silica at 2 theta = 22 degree. Silicon can be prepared by metallothermal reduction of pure silica at 650°C in Ar atmosphere for 1-3 hours, using magnesium (99% purity) as a reducing agent. High purity silicon (99.98 %) can be obtained by subsequently washing the as-reduced silica with HCl: H2O and HF: H2O solutions. The results from …

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Effect Of Electron Donor On Pe Polymerization, A Thongdonjui, W Trakarnpruk, R H. Strauss Jul 2009

Effect Of Electron Donor On Pe Polymerization, A Thongdonjui, W Trakarnpruk, R H. Strauss

Journal of Metals, Materials and Minerals

Ziegler-Natta catalyst was prepared from colloidal MgCl2 (from reaction between magnesium ethyl carbonate and aluminium sesquichloride, Al2Et3Cl3) followed by contact with TiCl4. Al/Mg and Ti/Mg molar ratios were studied as parameters affecting the catalyst synthesis. Catalytic performance and effect of electron donor on ethylene polymerization were investigated. Results showed that addition of electron donor (ethyl benzoate) increased activity balance when polymerizations were performed under hydrogen pressure of 1 bar and 3 bars. The morphology of the polymer can be improved while fine content of the polymer was reduced by addition of dicyclopentyl dimethoxysilane. A productivity of 17.3 and 15.0 kg …

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Recycling Of Medical Gown Nonwoven Fabric Manufacturing Waste As A Filler For High Density Polyethylene, P Singsatit, V Pimpan Jul 2009

Recycling Of Medical Gown Nonwoven Fabric Manufacturing Waste As A Filler For High Density Polyethylene, P Singsatit, V Pimpan

Journal of Metals, Materials and Minerals

The objective of this research is to recycle nonwoven fabric waste from medical gown - manufacturing process by using as a filler in high - density polyethylene (HDPE). Before nonwoven fabric waste was mixed with HDPE, this fabric waste was treated with 5, 10 and 15 %w/w of the fabric waste using the treatment time of 2, 3 and 4 hours. The chemical structure of treated fabric waste was confirmed by FT-IR spectroscopy while scanning electron microscopy was used to investigate its surface morphology. The samples were prepared by compression molding using the amount of fabric waste at 5, 10, …

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Determination Of Yield Behaviour Of Boron Alloy Steel At High Temperature, J Tungtrongpairoj, V Uthaisangsuk, W Bleck Jul 2009

Determination Of Yield Behaviour Of Boron Alloy Steel At High Temperature, J Tungtrongpairoj, V Uthaisangsuk, W Bleck

Journal of Metals, Materials and Minerals

The hot tensile test is a basic material testing method for investigation of the mechanical properties of steel at high temperature conditions. In industrial hot sheet forming processes such as hot stamping and hot gas metal forming, the influences of temperature and strain rate on microstructure and material behaviour play a significant role. In this work, sheet samples of steel grade 22MnB5 were examined using a hot deformation simulator. Different temperatures between 900 and 1200°C, which are above Ac3, and strain rates between 0.001 and 0.1 s-1 were considered. During the tensile test, a laser speckle extensometer (LSE) was deployed …

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Creep-Rupture Behavior Of Die-Cast Magnesium Alloys, Y B. Unigovski Jul 2009

Creep-Rupture Behavior Of Die-Cast Magnesium Alloys, Y B. Unigovski

Journal of Metals, Materials and Minerals

It is found that the relationship between the time-to-rupture tr and the time to the onset of tertiary creep tοt (tr /tot) in die-cast Mg-9Al alloy is equal to 1.3 and independent of stress, test temperature and diecasting parameters over the range examined. It is shown that the introduction of creep-rupture strain into Monkman-Grant relation modified by Dobeš and Milička demonstrates only the deviation range of the minimum creep rate from the average creep rate. The apparent activation energy Ec of creep is below the value of magnesium self-diffusion energy ESD up to 175o C. At higher temperatures, Ec > ESD, …

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Method For The Preparation Of Secondary Emulsions Of Fish Oil In Water, S Siramard, L Dubas, S T. Dubas Jul 2009

Method For The Preparation Of Secondary Emulsions Of Fish Oil In Water, S Siramard, L Dubas, S T. Dubas

Journal of Metals, Materials and Minerals

The method for the preparation of stable secondary emulsion has been detailed and discussed in terms of polymer capping and emulsion ratio. The dispersion of omega-3 oil in water by emulsion stabilized with casein was further coated with a polycationic polyelectrolyte, Poly (dially dimethyl ammonium chloride). The stability of the emulsion was studied by turbidity measurements using a UV-visible spectrophotometer. The particles size of the primary and secondary emulsion was investigated by light scattering and zeta potential measurements. Results shown in this article provide some details about the mechanism of the formation of secondary emulsion, mainly regarding the polymer/emulsion-mixing ratio.

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Effect Of Discarded Ppvc Contents On Thermal And Ultraviolet Resistance Of Acrylonitrile Butadiene Rubber, S Patcharaphun, S Chuypun Jul 2009

Effect Of Discarded Ppvc Contents On Thermal And Ultraviolet Resistance Of Acrylonitrile Butadiene Rubber, S Patcharaphun, S Chuypun

Journal of Metals, Materials and Minerals

In this investigation, the discarded plasticized-polyvinyl chloride (pPVC) from the extrusion of weather-seal was added into acrylonitrile butadiene rubber (NBR). Subsequently, the effects of pPVC contents on the mechanical properties, thermal, ultraviolet and swelling resistances of NBR were studied. The results indicated that scorch and cure time, tensile strength, hardness and swelling resistance increased with the increasing amount of pPVC added. Considering the thermal and ultraviolet resistances, it was observed that the mechanical properties of unfilled NBR decreased due to the desulphurization of the sulphur crosslinks and chain scission during heat and ultraviolet aging. However, the mechanical properties of the …

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Physical Properties Of Polyolefin/Bamboo Charcoal Composites, S Kittinaovarat, W Suthamnoi Jul 2009

Physical Properties Of Polyolefin/Bamboo Charcoal Composites, S Kittinaovarat, W Suthamnoi

Journal of Metals, Materials and Minerals

The physical properties of two kinds of polyolefin / bamboo charcoal composites, based upon polypropylene (PP) and low density polyethylene (LDPE), were studied for varying levels of charcoal inclusion between 0 and 20 phr. A Brabender mixer and two-roll mill were used for the mixing process of both polyolefin and bamboo charcoal composites, followed by compression moulding of the homogeneous mixtures to form the composite materials. The tensile strength and Young's modulus were both found to increase, whilst the elongation at break decreased, in a dose-dependent manner with increasing bamboo charcoal content in the composite materials. The tensile strength of …

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Interfacial Polymerization Of Water-Soluble Polyaniline And Its Assembly Using The Layer-By-Layer Technique, E Detsri, S T. Dubas Jul 2009

Interfacial Polymerization Of Water-Soluble Polyaniline And Its Assembly Using The Layer-By-Layer Technique, E Detsri, S T. Dubas

Journal of Metals, Materials and Minerals

The interfacial polymerization of aniline has been used to prepare water-soluble polyaniline. Polyaniline was made water-soluble by interfacial polymerization in the presence of poly(styrene sulfonated, sodium salt) (PSS), which acted as bundling agent to provide water solubility. The prepared polymer composite was later used for the fabrication of polyaniline nano-thin films using the layer-by-layer (LbL) self-assembly technique. Film produced by the LbL technique can be used in electro-chromic films, sensors or electro-catalytic films depending on the type of architectures. This paper first presents, a brief review on conducting polymer prepared by interfacial polymerization. Special interest is given to the synthesis …

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Mechanical Property Improvement Of Upe Resin From Glycolyzed Pet With Commercial Upe Resin, T Limpiti, P Potiyaraj Jul 2009

Mechanical Property Improvement Of Upe Resin From Glycolyzed Pet With Commercial Upe Resin, T Limpiti, P Potiyaraj

Journal of Metals, Materials and Minerals

The aim of this research paper is to improve mechanical properties of cured unsaturated polyester (UPE) resin prepared from glycolyzed PET by mixing with a commercial UPE resin. Postconsumer PET bottles were depolymerized by glycolysis reaction in excess propylene glycol at 190ºC in the presence of zinc acetate as a catalyst. The glycolyzed product was polyesterified with maleic anhydride and mixed with styrene monomer in order to obtain UPE resin. The prepared UPE resin was mixed with a commercially available general purpose grade UPE resin at various ratios. The mixed resins were cured using methyl ethyl ketone peroxide and cobalt …

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Characterizations Of Fibers Produced From Polypropylene/Silica Composite, N Srisawat, M Nithitanakul, K Srikulkit Jul 2009

Characterizations Of Fibers Produced From Polypropylene/Silica Composite, N Srisawat, M Nithitanakul, K Srikulkit

Journal of Metals, Materials and Minerals

Fumed silica particles filled polypropylene (PP) filament fibers were prepared by melt spin pilot plant. First, virgin PP and silicas(hydrophilic and hydrophobic) were premixed using twin screw extruder to prepare silica containing PP composite resin. Then, the resin composite was again mixed with virgin PP and spun into filaments with various filler loadings in the range of 0.5 - 2.5 wt%. The characterizations of spun composite fibers including crystallization temperature (DSC analysis), polymer orientation (sonic modulus) and the fine structure (XRD) were studied. XRD results showed β-form crystallinity peak in x-ray pattern of fiber drawn with low take-up speed (300 …

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Thermoplastic Cassava Starch/Sorbitol-Modified Montmorillonite Nanocomposites Blended With Low Density Polyethylene: Properties And Biodegradability Study, S Chuayjuljit, S Hosililak, A Athisart Jul 2009

Thermoplastic Cassava Starch/Sorbitol-Modified Montmorillonite Nanocomposites Blended With Low Density Polyethylene: Properties And Biodegradability Study, S Chuayjuljit, S Hosililak, A Athisart

Journal of Metals, Materials and Minerals

The objective of this research paper is to prepare environmentally friendly plastic materials from biodegradable cassava starch, montmorillonite (MMT) and low density polyethylene (LDPE). MMT was first modified by sorbitol via a solid state method. Results from X-ray diffraction (XRD) indicated that sorbitol molecules were intercalated in between MMT layers along 001 direction. Cassava starch was plasticized with sorbitol and formamide on a two-roll mill to obtain thermoplastic starch (TPS). The TPS/modified-MMT nanocomposites were prepared by means of melt blending of TPS with various amounts of MMT (0, 2, 4, and 6 phr). XRD and transmission electron microscopy (TEM) results …

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Welding Residual Stresses In Two Competing Single V-Butt Joints, P Wongpanya Jul 2009

Welding Residual Stresses In Two Competing Single V-Butt Joints, P Wongpanya

Journal of Metals, Materials and Minerals

During fabrication of welded components residual stresses are generated as a result of non-uniform temperature distribution during the welding and particularly the cooling processes. The residual stresses have a major effect on the overall performance of the components in service, especially when hydrogen is involved and the components might become prone to Hydrogen Assisted Cold Cracking (HACC). Up to the present, most of the welding standards and specifications to test the resistance of welds against HACC test are without consideration of the restraint intensity provided by the surrounding structure. This may lead to a misunderstanding of the welding heat treatment …

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Preparation And Characterization Of Particles From Chitosan With Different Molecular Weights And Their Trimethyl Chitosan Derivatives For Nasal Immunization, W Boonyo, H E. Junginger, N Waranuch, A Polnok, T Pitaksuteepong Dec 2008

Preparation And Characterization Of Particles From Chitosan With Different Molecular Weights And Their Trimethyl Chitosan Derivatives For Nasal Immunization, W Boonyo, H E. Junginger, N Waranuch, A Polnok, T Pitaksuteepong

Journal of Metals, Materials and Minerals

According to previous studies, molecular weights (MW) of chitosan presented an influence on the level of immune response to model antigen when administering with chitosan through nasal route. Moreover, trimethyl chitosan (TMC) with a degree of quaternization (DQ) of 40%, chitosan derivatives, was also shown to be the most potent nasal OVA delivery platforms compared to TMC with DQ of 20% and 60% in mice model. The aims of this study were to prepare particles from chitosan with difference MW and their TMC derivatives (DQ = 40%) and to characterize size, zeta potential, loading efficiency and release profile in order …

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Chitosan/Calcium Phosphate Composites Scaffolds Prepared By Membrane Diffusion Process, P Thanaphat, P Thunyakitpisal, W Techaboonyakiat Dec 2008

Chitosan/Calcium Phosphate Composites Scaffolds Prepared By Membrane Diffusion Process, P Thanaphat, P Thunyakitpisal, W Techaboonyakiat

Journal of Metals, Materials and Minerals

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) and Dicalcium phosphate dihydrate (CaHPO4.H2O, DCPD) were homogeneously hybridized into chitosan solution by membrane diffusion process. The threedimensional scaffolds were obtained by freeze-drying process. The organic and inorganic contents of scaffold were determined by using thermogravimetry analysis (TGA). The surface morphology of the scaffold and characteristic of calcium phosphate were investigated by scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDX), and X-ray diffraction (XRD), respectively. Compressive modulus was also determined by dynamic mechanical analysis (DMA). The hybridized inorganic content ranges from 35-45%. Both chitosan/HAp and chitosan/DCPD scaffolds showed interconnected porous structure. The calcium to phosphorus ratios …

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Application Of Chitosan In Rice Production, S Boonlertnirun, C Boonraung, R Suvanasara Dec 2008

Application Of Chitosan In Rice Production, S Boonlertnirun, C Boonraung, R Suvanasara

Journal of Metals, Materials and Minerals

Chitosan is a natural biopolymer which stimulates growth and increases yield of plants as well as induces the immune system of plants. The objectives of this study were to determine appropriate applications for increasing of the rice yield. The experiment was performed with randomized complete block design ( RCBD) with four replications. Four treatments were done as follows : no chitosan application, seed soaking with chitosan solution, seed soaking and soil application with chitosan solution and seed soaking and foliar spraying with chitosan solution. The results showed that application of chitosan by seed soaking and soil application four times throughout …

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Fabrication Of Porous Bioactive Glass-Ceramics Via Decomposition Of Natural Fibres, P Sooksaen, S Suttiruengwong, K Oniem, K Ngamlamiad, J Atireklapwarodom Dec 2008

Fabrication Of Porous Bioactive Glass-Ceramics Via Decomposition Of Natural Fibres, P Sooksaen, S Suttiruengwong, K Oniem, K Ngamlamiad, J Atireklapwarodom

Journal of Metals, Materials and Minerals

Porous bio glass-ceramics were prepared via natural fibres burning-out process. Glass-ceramics were fabricated by controlled crystallization of suitable glass compositions to give required crystalline phase/s. Porous structure was formed alongside during burning-out of natural fibres. Three glass batches were prepared in the SiO2-CaO-P2O5-K2O-Na2O-CaF2 glass system, then melted, quenched and milled to give fine glass powders. DTA thermograms for the three glass compositions showed crystallization temperatures between 720 and 760°C and Tg ranging between 508 and 645°C. Porous glass-ceramics were characterized for bulk density, phase evolution and microstructures. Different compositions resulted in different bulk densities and phases that crystallized out. Fluorapatite …

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Preparation Of N-Acetyl-D-Glucosamine Using Enzyme From Aspergillus Sp., P Setthakaset, R Pichyangkura, A Ajavakom, M Sukwattanasinitt Dec 2008

Preparation Of N-Acetyl-D-Glucosamine Using Enzyme From Aspergillus Sp., P Setthakaset, R Pichyangkura, A Ajavakom, M Sukwattanasinitt

Journal of Metals, Materials and Minerals

N-acetyl-D-glucosamine (GlcNAc) is one of the basic constituents of mammal cartilage, which is known to help repair deteriorating cartilage and relieve pain and inflammation in osteoarthritis patients. The preparation of GlcNAc from squid pen β-chitin by using Aspergillus sp. chitinase in enzymatic hydrolysis is studied. The cultivation of the fungus in colloidal chitin minimum media at pH 3.5 and 40°C for 5 days gives the highest chitinolytic activity of 3.1 U/mL. The crude enzyme obtained from the the cultivation is used in the hydrolysis of milled squid pen β-chitin (50μm) at pH 4 (acetic acid 2M) and 45°C using 22 …

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Factors Affecting Preparations Of Chitosan Microcapsules For Colonic Drug Delivery, K Huanbutta, M Luangtana-Anan, P Sriamornsak, S Limmatvapirat, S Puttipipatkhachorn, J Nunthanid Dec 2008

Factors Affecting Preparations Of Chitosan Microcapsules For Colonic Drug Delivery, K Huanbutta, M Luangtana-Anan, P Sriamornsak, S Limmatvapirat, S Puttipipatkhachorn, J Nunthanid

Journal of Metals, Materials and Minerals

This work aimed at studying factors affecting preparations of chitosan microcapsules for colonic drug delivery. Chitosan microcores (CS, 45kDa, 87% degree of deacetylation) containing diclofenac sodium (DS) coated with Eudragit®S100 (ED) were prepared by a desolvation technique. Sodium sulfate was used as a desolvating agent and the drying process was freeze-drying. Factors affecting morphology, particle size and zeta potential of microcapsules were evaluated, i.e. weight ratio of DS:CS:ED, surfactant (polysorbate 80), anti-adherent (silicon dioxide), and the use of sonication or homogenization in preparation processes. The weight ratio of DS:CS:ED at 1:2:6 provided the smallest microcapsules of about 82.37±1.61 micrometer in …

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Influence Of Reinforced Plastomers On Injection Moulds Wear, A Guzanová, J Brezinová Dec 2008

Influence Of Reinforced Plastomers On Injection Moulds Wear, A Guzanová, J Brezinová

Journal of Metals, Materials and Minerals

The contribution deals with wear of injection moulds based on aluminium alloy Alumec 89 in friction couples with plastomers reinforced with different glass fibres content. Friction relations in injection moulding were simulated by adhesion dry wear test with help of Amsler equipment with area contact of friction couple. Wear intensity was evaluated by friction coefficient and relative wear by weight loss. Simultaneously, changes of aluminium alloy surface morphology after wear in particular friction couples were analysed.

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Production Of Sponge Rubber For Monolayer Rubber Stamp Using Salt Leaching Method, W Trakanpruk, Y Rodthong Dec 2008

Production Of Sponge Rubber For Monolayer Rubber Stamp Using Salt Leaching Method, W Trakanpruk, Y Rodthong

Journal of Metals, Materials and Minerals

Sponge rubber used for monolayer rubber stamp was produced from nitrile butadiene rubber (NBR). Open cells in sponge rubber were created using salt leaching method. Effect of size and amount of sodium chloride which was used as a water soluble salt on the creation of open cells in the rubber was investigated. Carbon black was used as a filler. A different type of surfactant was added to increase the leaching out of salt from the rubber. Cure characteristics of the compound rubbers: maximum torque, minimum torque, scorch time and cure time as well as hardness of the prepared sponge rubber …

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