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[en] In this paper, the effect of wheat straw (WS) pretreatments and glue formulations on mechanical (i.e. Compressive Strength (CS) and Impact Strength (IS)) and water resistance properties (i.e. Thickness Swelling (TS) and water absorption (WA)) of particle board have been investigated and the results have been compared with conventional wooden particleboard. Wheat straw was treated with steam available at 110 degree C and 20 psig, for the retention time of 5, 10 and 15 min. The solution of 10% HCl was also used for removing the lignin. Particleboard was prepared by bonding treated WS with four types of glue recipes of synthetic and natural binders like urea formaldehyde (UF), polyvinyl acetate (PVA), corn flour (CF) and wheat flour (WF). The particle board was formed at the hydraulic pressure and temperature of 2800 psig and 80 degree C respectively. It was observed that WS particleboard has low mechanical strength and high water resistance in comparison with conventional board. The particle board prepared with HCl cured wheat straw and glue having high urea formaldehyde and corn flour has higher CS and IS as well as low TS and WA. It may be concluded that wheat straw is a good substitute of wood for particle board while using HCl as a modifying chemical and strong binders like urea formaldehyde and corn flour. (author)
[en] The DOE is in the process of developing technologies for converting plant matter other than feed stock, e.g., corn stover, into biofuels. The goal of this research project was to determine what the farming community thinks of ethanol as a fuel source, and specifically what they think of bioethanol produced from corn stover. This project also assessed the image of the DOE and the biofuels program and determined the perceived barriers to ethanol-from-stover production
[en] Chemical transformation of agricultural wastes commonly encountered in Pakistan, was attempted using sulfuric acid as hydrolyzing agent. The yield of sugar from sugarcane leaves after hydrolysis with 0.6 N-sulfuric acid was the highest that was 34%, while the yield of sugar from grass, rice husk and wheat straw was about 22%. Other sample also exhibited good results. (author)
[en] This study investigated saccharification and protein-level responses to the candidate biofuel feedstocks corn stover (CS) and soybean residue (SR) by the gut of a lower termite. The focus termite was Reticulitermes flavipes, which is a highly efficient digester of wood lignocellulose that houses a mixture of prokaryotic and eukaryotic microbes in its gut. Our specific objectives were to (i) measure saccharification potential of the CS and SR feedstocks by termite gut protein extracts, (ii) identify specific proteins in the termite gut responding to feeding on CS and SR diets, and (iii) evaluate gut lignocellulase and accessory enzyme activity responses to CS and SR feeding. Cellulose paper was the control diet. Although CS was saccharified at higher levels, termite gut protein extracts saccharified both CS and SR irrespective of feedstock loading. Consumption of the CS and SR feedstocks by termites resulted in surprisingly few differences in gut protein profiles, with the main exception being elevated myosin abundance with SR feeding. Activity of potential lignocellulases and accessory enzymes was generally similar between CS and SR fed guts as well; however, cellobiohydrolase/exoglucanase activity was higher with CS feeding and glutathione peroxidase activity with SR feeding. These findings have significance from two perspectives. First, SR feeding/digestion appears to cause physiological stress in the termite gut that likely would extend to other types of microbial environments including those within industrial bioreactors. Second, because termites can survive on exclusive CS and SR diets and their guts exhibit clear CS and SR saccharification activity, this validates the R. flavipes system as a potential source for CS and SR degrading enzymes; in particular, cellobiohydrolases/exoglucanases and glutathione peroxidases from this system may play roles in CS and SR breakdown.
[en] Corn stover is a common agricultural product in areas with large amounts of corn production. It consists of the leaves and stalks of maize (Zea mays ssp. mays L.) plants left in field following harvest of the cereal grain. Stover makes up about half of the yield of a crop and is similar to straw. This material can be processed as cellulosic ethanol without diverting food for fuel. Unlike grain ethanol, ethanol from stover has a positive effect on food supply and grain price. Diverting corn grain into making fuel has been blamed as one of the causes of the world-wide increase in food prices. The goal of this study was to evaluate the potential of producing cellulose ethanol from corn stover under different seeding densities. The study was an output of the research fellowship of the main author in Kansas State University (KSU), under the USDA International Borlaug Fellowship. Corn stover was collected from the experimental set up of the Agronomy Department at KSU where Manhattan Corn was planted 2X, 1.5X, 1X, 0.5X the recommended 64K plants/ha; and no competition. A randomized complete block design was used with four replications. Stover preparation for fermentation began by drying, grinding to 200 μm, mild acid pre-treatment, and enzymatic hydrolysis using the combined activity of Cellulase and Novozyme under strictly controlled laboratory conditions. Cellulose, hemicelluloses, and lignin contet were determined for each sample using NREL protocols. Glucose and Xylose released per gm of biomass after acid pre-treatment and enzymatic hydrolysis were determined using HPLC. Baker's yeast (S. cereviaccae) was introduced to the biomass following enzymatic saccharification. Fermentation carried out at 300C in a centrifuge running at 100 rpm for 48 hours. Compositional analysis of corn stover fractions was highest in plant population with no competition but remained fairly comparable across planting densities. Cellulos varied from 36 to 42%, hemicellulose, 24-27%, and Lignin, 14-16%. Saccharification efficiency (glucose released from cellulose), ranges from 26-37%. 100% conversion of cellulose to glucose was far from ideal due to presence of lignin in the biomass that restricted due to the presence of lignin in biomass that restricted the full exposure fiber for enzymatic reaction. The recommended seeding rate showed the highest yield of fermentable carbohydrates but did not differ significantly from the other seeding rates. Ethanol conversion based on the glucose released after enzymatic saccharification ranged from 81.42 to 91.67%. Given the saccharification and ethanol conversion efficiencies derived from this experiment, the mean ethanol yield per dry ton biomass of corn stover was approximately 88 L-142 L. Normal seeding density yields 5.66 tons dry corn stover/ha. (author)
[en] Data concerning the methods of synthesis, chemical transformations and application of levulinic acid are analysed and generalised. The wide synthetic potential of levulinic acid, particularly as a key compound in the synthesis of various heterocyclic systems, saturated and unsaturated ketones and diketones, difficultly accessible acids and other compounds is demonstrated. The accessibility of levulinic acid from hexose-containing wood-processing and agricultural wastes is noted. The bibliography includes 260 references.
[en] Rice husk is being used as a source of energy in many heat generating system because of its high calorific value and its availability in many rice producing areas. Rice husk contains approximately 20% silica which is presented in hydrated form. This hydrated silica can be retrieved as amorphous silica under controlled thermal conditions. Uncontrolled burning of rice husk produces crystalline silica which is not reactive silica but can be used as filler in many applications. Amorphous silica is reactive silica which has better market value due to its reactive nature in process industry. The present study deals with the production of amorphous silica at various temperatures from rice husk. Various ashes were prepared in tube furnace by changing the burning temperatures for fixed time intervals and analyzed by XRD. It has been observed that for two hours calculation's of rice husk renders mostly amorphous silica at 650 degree C where as at higher temperatures crystalline silica was obtained. (author)
[en] Data on the present use of bioresources, i.e. fuelwood, charcoal, and agroindustrial wastes, were collected and analyzed with respect to the national and regional energy balances in Greece. In the period 1980 - 1985, biomass was found to be the third significant energy source in this country, contributing a fairly constant 5 % of the total energy needs. The contribution of bioenergy at the regional level was found to be considerably higher, i.e. more than 10% in most Greek regions, whereas in three major regions there is a clearly increasing trend towards the use of bioenergy. (author)
[en] In describing the present status of composite materials made from fibrous materials and synthetic polymers, it should first be mentioned that Korea produces almost no polymer-wood combinations. However, Korea has been very active in the production of various resin-fibrous material combinations that mainly employ thermosetting resins as binding agents to improve the quality of woods and other fibrous materials. Plywood, chip board, hard board and straw board are some examples. Korean forest resources are not sufficient to meet industrial needs. Only a small amount of domestic pine timber is used for ground pulp production. However, plywood production, which started some ten years ago, has increased to where domestic consumption is now fully supplied and annual exports are now worth more than 40 million US dollars. Although whole log timber for the industry is imported, urea and formalin for adhesives are produced domestically. To develop an effective means for using waste lumber, chip board, fibre board and hard board have been produced since 1962 and the production of straw board has been started as a means of utilizing agricultural wastes