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Sirijutaratana Covavisaruch - One of the best experts on this subject based on the ideXlab platform.
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effects of Rice Hull particle size and content on the mechanical properties and visual appearance of wood plastic composites prepared from poly vinyl chloride
Journal of Bionic Engineering, 2013Co-Authors: Nawadon Petchwattana, Sirijutaratana CovavisaruchAbstract:This research aims to develop Wood Plastic Composites (WPCs) from Rice Hull and poly(vinyl chloride) (PVC). The influences of the Rice Hull particle size and content on the mechanical properties and the visual appearance of the WPC decking board were investigated. The experimental results revealed that the impact strength tended to decrease with increasing Rice Hull content. The composites with larger particle sizes exhibited higher impact strength. Under tensile and flexure load, higher Rice Hull content induced greater modulus and ultimate strength when the Rice Hull was applied at less than 60 phr. Beyond this concentration, the modulus and the strength dropped due to the formation of Rice Hull agglomerates. The smaller particles of the milled Rice Hull, the greater tendency there was for them to act as a pigment to form a darker shade close that of the Rice Hull on the composite decking board. The larger particle sizes were 106 μm and beyond simply embedded in the white PVC matrix.
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mechanical properties thermal degradation and natural weathering of high density polyethylene Rice Hull composites compatibilized with maleic anhydride grafted polyethylene
Journal of Polymer Research, 2012Co-Authors: Nawadon Petchwattana, Sirijutaratana Covavisaruch, Sirapat ChanakulAbstract:The influences of Rice Hull (RH) contents and particle sizes on the mechanical, physical, thermal and morphological properties of high density polyethylene (HDPE)/RH composites were investigated in the current research. Further study was conducted by incorporating maleic anhydride grafted polyethylene (MA-g-PE) to improve the interfacial adhesion between HDPE and RH. Experimental results indicated that the flexural and the tensile strengths were increased upon raising the silica-rich RH contents. With the addition of RH, the composites became brittle as was reflected by the lower impact strength. An improvement of all the flexural, tensile and impact strength was evident when the MA-g-PE was added in all levels. SEM micrographs revealed some RH pulled-out and numerous interfacial cavities occurred within the untreated HDPE/RH composites. With the presence of the compatibilizer, the interfacial adhesion was significantly improved. Lower water absorption was found when MA-g-PE was added in all compositions. Under UV exposure, the colors of the composites found to paler shade.
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influences of particle sizes and contents of chemical blowing agents on foaming wood plastic composites prepared from poly vinyl chloride and Rice Hull
Materials & Design, 2011Co-Authors: Nawadon Petchwattana, Sirijutaratana CovavisaruchAbstract:Abstract This research aims to investigate the effects of chemical blowing agent (CBA) contents and particle sizes on the properties of foamed poly(vinyl chloride) (PVC)/Rice Hull (RH) composites. Fine particles of azodicarbonamide (AC) at 5, 8, 11 and 22 μm were modified with 20% by weight of ZnO and used at 0–3.0% by weight. The average cell size and density of the PVC/RH foamed profiles were reduced as the content of modified azodicarbonamide (mAC) increased. Larger mAC particles lowered the density more effectively. Maximum reduction of density by 46% was achieved when mAC 22 μm was applied at 2.0% by weight. Larger blowing particles led to PVC/RH foam with greater flexural modulus and strength. Greater impact strength, observed when 5 μm mAC was applied, resulted from the rather thick cell wall created abundantly when fine mAC was applied.
Nawadon Petchwattana - One of the best experts on this subject based on the ideXlab platform.
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effects of Rice Hull particle size and content on the mechanical properties and visual appearance of wood plastic composites prepared from poly vinyl chloride
Journal of Bionic Engineering, 2013Co-Authors: Nawadon Petchwattana, Sirijutaratana CovavisaruchAbstract:This research aims to develop Wood Plastic Composites (WPCs) from Rice Hull and poly(vinyl chloride) (PVC). The influences of the Rice Hull particle size and content on the mechanical properties and the visual appearance of the WPC decking board were investigated. The experimental results revealed that the impact strength tended to decrease with increasing Rice Hull content. The composites with larger particle sizes exhibited higher impact strength. Under tensile and flexure load, higher Rice Hull content induced greater modulus and ultimate strength when the Rice Hull was applied at less than 60 phr. Beyond this concentration, the modulus and the strength dropped due to the formation of Rice Hull agglomerates. The smaller particles of the milled Rice Hull, the greater tendency there was for them to act as a pigment to form a darker shade close that of the Rice Hull on the composite decking board. The larger particle sizes were 106 μm and beyond simply embedded in the white PVC matrix.
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mechanical properties thermal degradation and natural weathering of high density polyethylene Rice Hull composites compatibilized with maleic anhydride grafted polyethylene
Journal of Polymer Research, 2012Co-Authors: Nawadon Petchwattana, Sirijutaratana Covavisaruch, Sirapat ChanakulAbstract:The influences of Rice Hull (RH) contents and particle sizes on the mechanical, physical, thermal and morphological properties of high density polyethylene (HDPE)/RH composites were investigated in the current research. Further study was conducted by incorporating maleic anhydride grafted polyethylene (MA-g-PE) to improve the interfacial adhesion between HDPE and RH. Experimental results indicated that the flexural and the tensile strengths were increased upon raising the silica-rich RH contents. With the addition of RH, the composites became brittle as was reflected by the lower impact strength. An improvement of all the flexural, tensile and impact strength was evident when the MA-g-PE was added in all levels. SEM micrographs revealed some RH pulled-out and numerous interfacial cavities occurred within the untreated HDPE/RH composites. With the presence of the compatibilizer, the interfacial adhesion was significantly improved. Lower water absorption was found when MA-g-PE was added in all compositions. Under UV exposure, the colors of the composites found to paler shade.
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influences of particle sizes and contents of chemical blowing agents on foaming wood plastic composites prepared from poly vinyl chloride and Rice Hull
Materials & Design, 2011Co-Authors: Nawadon Petchwattana, Sirijutaratana CovavisaruchAbstract:Abstract This research aims to investigate the effects of chemical blowing agent (CBA) contents and particle sizes on the properties of foamed poly(vinyl chloride) (PVC)/Rice Hull (RH) composites. Fine particles of azodicarbonamide (AC) at 5, 8, 11 and 22 μm were modified with 20% by weight of ZnO and used at 0–3.0% by weight. The average cell size and density of the PVC/RH foamed profiles were reduced as the content of modified azodicarbonamide (mAC) increased. Larger mAC particles lowered the density more effectively. Maximum reduction of density by 46% was achieved when mAC 22 μm was applied at 2.0% by weight. Larger blowing particles led to PVC/RH foam with greater flexural modulus and strength. Greater impact strength, observed when 5 μm mAC was applied, resulted from the rather thick cell wall created abundantly when fine mAC was applied.
Marco Antônio Záchia Ayub - One of the best experts on this subject based on the ideXlab platform.
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Bioconversion of soybean and Rice Hull hydrolysates into ethanol and xylitol by furaldehyde-tolerant strains of Saccharomyces cerevisiae, Wickerhamomyces anomalus, and their cofermentations
Biomass Conversion and Biorefinery, 2017Co-Authors: Nicole Teixeira Sehnem, Lilian Raquel Hickert, Fernanda Cunha-pereira, Marcos Antonio Morais, Marco Antônio Záchia AyubAbstract:The aims of this work were to evaluate the ability of furaldehyde-tolerant yeast strains Saccharomyces cerevisiae P6H9 and Wickerhamomyces anomalus WA-HF5.5 and their cofermentations and to convert soybean and Rice Hull hydrolysates into ethanol and xylitol. In batch shaker cultures, the strains showed the ability to tolerate high osmotic pressure (1918 mOsmkg^−1), completely depleting furaldehyde in the first 12 h of cultivations, while converting the hydrolysate sugars into ethanol. Highest ethanol yields of 0.37 g g^−1 and productivity of 0.31 g L^−1 h^−1 were obtained in the cofermentation using Rice Hull hydrolysate as substrate. The concentration of sugars in soybean Hull hydrolysate proved to be inadequate as substrate for the cultivation of these strains, showing a low ethanol productivity of 0.08 g L^−1 h^−1. Bioreactor cultivations of S. cerevisiae on Rice Hull hydrolysate under anaerobiosis showed a relatively high ethanol productivity of 6.7 g L^−1 h^−1, whereas the bioreactor cofermentation produced xylitol to yields of 0.86 g g^−1 under conditions of oxygen limitation.
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simultaneous saccharification and co fermentation of un detoxified Rice Hull hydrolysate by saccharomyces cerevisiae icv d254 and spathaspora arborariae nrrl y 48658 for the production of ethanol and xylitol
Bioresource Technology, 2013Co-Authors: Lilian Raquel Hickert, Priscila Brasil De Souzacruz, Carlos A Rosa, Marco Antônio Záchia AyubAbstract:Co-fermentation and simultaneous saccharification of Rice Hull hydrolysate (RHH) were investigated for the production of ethanol and xylitol by Saccharomyces cerevisiae, Spathaspora arborariae, or the combination of both. In bioreactor cultures under oxygen limitation, S. cerevisiae was capable of metabolizing glucose from RHH, which contained small amounts of acetic acid, furfural, and hydroxymethylfurfural, achieving ethanol yields of 0.45 and concentrations of 10.5 g L(-1). In the co-culture of S. cerevisiae and S. arborariae pentoses and hexoses from RHH, were converted to ethanol and xylitol, with yields of 0.48 and 0.39, and concentrations of 11 g L(-1) and 3 g L(-1), respectively. The simultaneous saccharification and co-fermentation using both yeasts produced ethanol and xylitol to final concentrations of 14.5 g L(-1) and 3 g L(-1), respectively. Results showed good prospects to use co-cultures of S. cerevisiae and S. arborariae for the bioconversion of RHH into ethanol and xylitol without further detoxification.
A Proctor - One of the best experts on this subject based on the ideXlab platform.
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a simple method for production of pure silica from Rice Hull ash
Bioresource Technology, 2000Co-Authors: U Kalapathy, A Proctor, J L ShultzAbstract:Rice Hull ash (RHA), a waste product of the Rice industry is rich in silica. A simple method based on alkaline extraction followed by acid precipitation was developed to produce pure silica xerogels from RHA, with minimal mineral contaminants. The silica gels produced were heated to 80 o C for 12 h to obtain xerogels. Silica and mineral contents of xerogels were determined by energy dispersive X-ray (EDX) and inductively-coupled plasma (ICP) emission spectrometers, respectively. Xerogels produced from RHA had 93% silica and 2.6% moisture. The major impurities of silica produced from RHA at an extraction yield of 91% were Na, K, and Ca. Acid washing prior to extraction resulted in silica with a lower concentration of Ca (<200 ppm). However, final water washing of the xerogel was more eAective in producing silica with lower overall mineral content (Na < 200 ppm and K < 400 ppm). X-ray diAraction patterns revealed the amorphous nature of silica xerogel. Fourier transform infrared (FTIR) data indicated the presence of siloxane and silanol groups. ” 2000 Elsevier Science Ltd. All rights reserved.
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silica xerogels from Rice Hull ash structure density and mechanical strength as affected by gelation ph and silica concentration
Journal of Chemical Technology & Biotechnology, 2000Co-Authors: U Kalapathy, A Proctor, J ShultzAbstract:Silica xerogels were produced from Rice Hull ash (RHA), and the structure, density and mechanical strength of the gels were investigated. Silica was extracted as sodium silicate from RHA using 1M NaOH. This silicate solution was concentrated by volume reduction and used to obtain silica concentrations of 0.04, 0.06, 0.08, 0.10, and 0.12 g cm−3. The pH values of these silicate solutions were adjusted to 9.0, 10.0, 10.5, or 11.0 to produce silica gels. The silica gels produced were then dried at 80 °C for 24 h. X-ray diffraction demonstrated the amorphous nature of silica gels. Diffuse reflectance Fourier Transform Infrared (FTIR) spectroscopy was used to investigate the effect of gelation pH, and silica concentration on the chemical structure of the xerogel and concomitant effect on density and mechanical strength of the xerogel. The FTIR spectra demonstrated that at higher pH of gelation, siloxane bonding was the primary network in the xerogel. As the pH of gelation decreased, the structural silica gel network became the major interaction in the silica xerogel. At each gelation pH, the silica gel network increased with increase in silica concentration. The higher pH led to condensed glassy solids, while higher silica concentration produced highly porous silica xerogel. Hence, gelation pH and silica concentration of gel-forming solution had significant effects on the density and the mechanical strength of xerogels produced from Rice Hull silica. © 2000 Society of Chemical Industry
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Rice Hull ash and silicic acid as adsorbents for concentration of bacteriocins
Applied and Environmental Microbiology, 1998Co-Authors: M E Janes, A Proctor, Ramakrishna Nannapaneni, M G JohnsonAbstract:Yang et al. (16) purified bacteriocins (pediocin AcH, nisin, sakacin A, and leuconocin Lcm1) by adsorbing them to heat-killed producer bacteria. They found that the adsorption of all bacteriocins tested was pH dependent with maximum adsorption occurring at a pH near 6.0. By reducing the pH to 2.0 and adding 50 mM sodium dodecyl sulfate (SDS), they were able to release 93 to 100% of the bound bacteriocins from the producer cells. Daba et al. (5) also purified pediocin PA-1 by adsorption onto producer cells but desorbed the bacteriocin by acid treatment alone and recovered only 10% of the initial concentration. Bacteriocins (nisin, pediocin PO3, brevicin 286, and piscicolin 126) have also been removed from fermentation broths by adsorption onto diatomic calcium silicate (4). However, once adsorbed to diatomic calcium silicate, these bacteriocins could not be desorbed between a pH range of 1.0 to 12.0 except with the addition of 1% SDS. Methods therefore need to be devised to extract large quantities of purified bacteriocins from crude bacteriocin-containing culture supernatants for use in food preservation. Rice Hull ash (RHA) is a coproduct of Rice milling and is composed primarily of silica and carbon (12). Analysis of Rice Hull silica by infrared spectroscopy indicated it was similar to silicic acid (13). Proctor and Palaniappan (11) found that heating RHA at 500°C for 10 h and treating it with sulfuric acid improved the adsorption of lutein from soy oil. However, the acid-activated RHA (aRHA) reduced the extraction of free fatty acids from crude soy oil while the heat-treated alkaline RHA (kRHA) effectively removed the free fatty acids from crude soy oil (14). However, under commercial bleaching conditions, kRHA was not effective in reducing the levels of pigments, free fatty acids, and peroxides from soy oil (13). In addition, aRHA was used to effectively immobilize a lipase produced by Candida cylindracea (15). In this study, the optimum pHs for adsorption of five bacteriocins onto kRHA, aRHA and silicic acid (SA) were investigated. In addition, the optimum conditions for the desorption of bacteriocins from kRHA, aRHA, and SA and resulting specific activities were determined. The purity of the resulting bacteriocins after desorption was determined by SDS-polyacrylamide gel electrophoresis (PAGE).
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silica gel from Rice Hull ash preparation and characterization
Cereal Chemistry, 1998Co-Authors: Savita R Kamath, A ProctorAbstract:ABSTRACT Rice Hulls, a waste coproduct of the Rice industry, is composed of 20% silica. The objectives of this study were to develop a method to recover silica from Rice Hull ash and produce silica gel, and to determine the physical and chemical properties of the Rice Hull silica gel (RHSG) relative to Trisyl 300, a commercial silica gel. Rice Hull ash consisting of 61% silica and 36% carbon was dispersed in sodium hydroxide to dissolve the silica and produce a sodium silicate solution. The latter was titrated to pH 7 with 1M sulfuric acid to obtain a gel at neutral pH. The RHSG was aged, washed, and dried under specific conditions to get a final product that was slightly basic and had a moisture content >65%. Energy dispersive X-ray spectrometry indicated that silicon was the most abundant element present in RHSG and Trisyl 300. Elemental analyses by inductively coupled plasma emission spectroscopy indicated a greater concentration of sodium and sulfur in RHSG relative to that in Trisyl 300. RHSG surface...
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mode of oleic acid adsorption on Rice Hull ash cristobalite
Journal of the American Oil Chemists' Society, 1995Co-Authors: A Proctor, C Adhikari, G D BlyholderAbstract:Fourier transform infrared spectroscopy was used to investigate the adsorption of oleic acid (OA) onto dry Rice Hull ash (RHA) silica. Adsorption partially occurred by surface hydrogen bonding of the carboxylic acid. There was also formation of carboxylate ions by reaction of OA with residual potassium oxide. These ions were strongly bound by the ash. Isopropanol inhibited OA adsorption by H-bonding and encouraged desorption of H-bonded OA, but without itself being significantly bound. RHA with 40% moisture also adsorbed a small amount of OA by H-bonding and reacted with OA to form and adsorb carboxylate ions.
Canping Pan - One of the best experts on this subject based on the ideXlab platform.
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simultaneous determination of 124 pesticide residues in chinese liquor and liquor making raw materials sorghum and Rice Hull by rapid multi plug filtration cleanup and gas chromatography tandem mass spectrometry
Food Chemistry, 2018Co-Authors: Yongtao Han, Le Song, Shaowen Liu, Nan Zou, Yuhong Qin, Canping PanAbstract:Abstract A multi-residue method was developed for the determination of 124 pesticide residues in Chinese liquor and liquor-making raw materials (sorghum and Rice Hull) by rapid Multi-plug Filtration Cleanup (m-PFC) and GC–MS/MS detection. Different combination and proportion sets of sorbents were initially optimized for each matrix with a dispersive solid-phase extraction (d-SPE) procedure. Satisfactory linearity was obtained for the 124 pesticides with regression coefficients (R 2 ) greater than 0.9901. Mean recoveries of 121 pesticides were in the range of 71–121% with Relative Standard Deviations (RSDs) lower than 16.8% except cyprodinil, diflufenican and prothioconazole. The Limit of Quantification (LOQs) was in the range of 1.0 × 10 −4 –5.0 × 10 −3 mg kg −1 and the Limit of Detection (LODs) ranged from 3.0 × 10 −5 to 1.5 × 10 −3 mg kg −1 for the 124 pesticides in the matRices. It is demonstrated the m-PFC procedure is superior to the d-SPE method and it could be used to routinely monitor of pesticide residues in market samples.
