SYNTHESIS OF SiC WHISKER AND ITS APPLICATION IN COMPOSITE MATERIALS

The SiC whiskers (SiCw) synthesized from rice hulls is studied in this paper. The properties of the application in the composite materials are tested, and also compared with the SiCw produced in US and Japan, the results indicate that the SiCw produced by this method is mainly straight crystals with multi nodes on face, the main type is P-SiC. lt has many advantages such as high strength and excellent oxidation resistance to high temperature. The Si3N4 ceramic composite materials reinforced and toughened with the SiCw, δfRT of the material is (856±22)MPa, δf300℃ is approximately (418. 5±14. 2) MPa and Klc is approximately (11. 3±1. 0) MPa m1/2. Besides, the application of the SiCw in the engineering materials of mining is forecasted.

Development of a Biological Filter Utilizing Organic Growth Media for Wastewater Treatment and Nitrogen Oxidation

Loss of ammonia-nitrogen to volatilization and the over application of phosphorus in agricultural wastewaters has led to excess phosphorus build up in topsoil and in surface waters. In order to increase the usable amount nitrogen in agricultural wastewaters, the wastewaters underwent a nitrogen treatment process consisting of a hanging basket biological filter. The filters utilized never before used biological growth media, rice hulls, to assist in the formation of a mature biofilms as the oxidation of ammonia to nitrate. The filter design was used on a lab scale that treated both artificial wastewater and dairy parlor wastewater treated with a lime precipitation step for phosphorus treatment. The filters were tested to see if bio-fouling occurred in the filter media bed under high nitrogen loading, if the rice hulls could withstand an extended time frame as bacterial growth media, and to see if the oxidation of ammonia to nitrate would occur. A 50% reduction in ammonia occurred between 30 and 48 hrs in each trial with eventual nitrite oxidation reported in the final two trials. Statistical analysis preformed determined that the ammonia removal rates at the beginning of both the synthetic wastewater and dairy parlor wastewater ten-day tests were statistically similar, but varied toward the end of the trials.

High-Strength Carbon Materials and Elastomers on the Basis of Carbon-Silicon Nanocomposites

The processes for obtaining C-SiO2 and C-βSiC nanocomposites from the rice hulls have been studied. On the basis of these composites, some carbon materials and rubber products with the increased physical and mechanical properties have been obtained. The tensile strength of the carbon products with C-SiO2 is 92-96 MPa and with C-βSiC： 112-118 MPa in comparison with 70-80 MPa for standard products from artificial graphite. Nominal strength and resistance to tensile strain of the carbon material with C-SiO2 increase by 15%-20% as compared to the carbon material with carbon black.

Effects of Rice Hull Particle Size and Content on the Mechanical Properties and Visual Appearance of Wood Plastic Composites Prepared from Poly（vinyl chloride）

This research aims to develop Wood Plastic Composites （WPCs） from rice hull and poly（vinyl chloride） （PVC）. The in- fluences 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.

Removal of sodium diclofenac from aqueous solutions by rice hull biochar

Diclofenac is an ecotoxic pharmaceutical compound affecting both aquatic and terrestrial ecosystems even at low concentrations.In this study,batch adsorption experiments were conducted to remove sodium diclofenac(SD)from aqueous solutions using rice hull biochar(RHB)adsorbents.Higher SD removals were obtained with increasing initial SD concentration,RHB dosage,contact time,and decreasing initial pH.Isotherm studies revealed that Langmuir isotherm best fitted the experimental data with the highest coefficient of determination for both pH 2(R2=0.9827)and pH 7(R2=0.9460).For kinetic studies,the pseudo second-order model gave R2=0.9999 for both pH 2 and pH 7.SD removals reached up to 97%at pH 2 and up to 80%at pH 7.Higher SD removals were achieved at solution pH lower than the adsorbent pHpzc since electrostatic repulsion was eliminated.Fourier-transform infrared analysis showed the major involvement of C=O in the adsorption process.This study demonstrated the potential of using agricultural residues such as rice hulls for the treatment of wastewater contaminated with pharmaceutical compounds.

New Aliphatic Alcohol and Ester Constituents from Rice Hulls of Oryza sativa

Six new aliphatic alcohol and ester compounds of n-octacos-9-enyl propionate （1）, 4-（3-formylheptyl）cyclohexyl 4-（cyclohexylcarbonyloxymethyl）cyclohexyl-carboxylate （2）, n-hentriacont-25-en-5α-ol （3）, n-hexetriacont-9,26-dien-8α,11β,23α-triol （4）, n-tetracontan-15α-ol （5） and n-tritetracontan-5α-ol （6） were isolated from the hulls of Oryza sativa. The structures were established on the basis of spectroscopic analysis.

The pleiotropic ABNORMAL FLOWER AND DWARF1 affects plant height, floral development and grain yield in rice

Moderate plant height and successful establishment of reproductive organs play pivotal roles in rice grain production. The molecular mechanism that controls the two aspects remains unclear in rice. In the present study,we characterized a rice gene, ABNORMAL FLOWER AND DWARF1（AFD1） that determined plant height, floral development and grain yield. The afd1 mutant showed variable defects including the dwarfism, long panicle, low seed setting and reduced grain yield. In addition, abnormal floral organs were also observed in the afd1 mutant including slender and thick hulls, and hull-like lodicules.AFD1 encoded a DUF640 domain protein and was expressed in all tested tissues and organs. Subcellular localization showed AFD1-green fluorescent fusion protein（GFP） was localized in the nucleus. Meantime, our results suggested that AFD1 regulated the expression of cell division and expansion related genes.