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Cellulosic Materials (cellulosic + material)
Selected AbstractsBioethanol from agricultural waste residuesENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2008Pascale Champagne Abstract Under the Kyoto Protocol, the Government of Canada has committed to reducing its greenhouse gas emissions by 6% from 1990 levels between 2008 and 2012. Ethanol-blended gasolines have the potential to contribute significantly to these emission reductions. Ethanol is derived from biologically renewable resources and can be employed to replace octane enhancers and aromatic hydrocarbons or oxygenates. To date, the ethanol production industry in Canada is comprised mainly of small-scale plants producing ethanol primarily from agricultural crops as feedstock. Research interests in the area of bioethanol production from organic waste materials emerged in the late 1980. Significant advances in lignocellulosic material extraction and enzymatic hydrolysis have been reported in the last decade, however, continued research efforts are essential for the development of technically feasible and economically viable large-scale enzyme-based biomass-to-ethanol conversion processes. This research aims to develop and test an enzyme-based biomass-to-ethanol conversion process, which employs organic waste materials, such as livestock manures, as alternative sources of cellulosic material feedstock. The source of the livestock manure, manure management practices and cellulose extraction procedures have a significant impact on the quantity and quality of the cellulosic materials derived. As such, raw feedstock materials must be carefully characterized to assess the impact of these factors on the yield of bioethanol and residual end products. The success of cellulose-to-ethanol conversion processes for cellulose extracted from these waste materials as feedstock is generally a function of cellulose fiber pretreatment, enzyme selection and operating conditions. These will differ depending on the source of the waste material feedstock. The long-term benefits of this research will be to introduce a sustainable solid waste management strategy for a number of livestock manure and other lignocellulosic waste materials; contribute to the mitigation in greenhouse gases through sustained carbon and nutrient recycling; reduce the potential for water, air, and soil contamination associated with land disposal of organic waste materials; and to broaden the feedstock source of raw materials for the ethanol production industry. © 2007 American Institute of Chemical Engineers Environ Prog, 2008 [source] Ignition studies of cerium nitrate treated towelsFIRE AND MATERIALS, Issue 3 2006C. L. Beyler Abstract This study evaluated the ignitability of cotton towel material saturated with an oxidizer solution of 0.5 N cerium nitrate in 2 N nitric acid. Four types of ignition testing were performed in this work: self-heating oven tests, hot object ignition tests, radiative smoldering ignition tests, and piloted flaming ignition/burning rate tests. Results indicate that cerium nitrate significantly enhances the ignitability of the towels. Self-heating properties of cerium nitrate treated towels were measured using the standard constant temperature oven method described by Bowes. Based upon these self-heating properties, self-heating is not a hazard for storage scenarios other than bulk storage (depths of several meters) of cerium nitrate treated towels at room temperature. Surface ignition of hot objects was observed for object temperatures as low as 250°C placed upon room temperature cerium nitrate treated towels. Ignition for hot objects buried within a pile of towels occurred for object temperatures as low as 230°C. Radiant heating tests of cerium nitrate treated towels showed initiation of smolder at heat fluxes as low as 3 kW/m2 at surface temperatures as low as 175°C. This compares with ordinary cellulosic materials that require 7,8 kW/m2 heat fluxes and temperatures of 250°C. All four scenarios demonstrate enhanced ignitability and burning rates of cerium nitrate treated towels. Copyright © 2005 John Wiley & Sons, Ltd. [source] A numerical method for the evaluation of non-linear transient moisture flow in cellulosic materialsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2006U. Nyman Abstract A numerical method for the transient moisture flow in porous cellulosic materials like paper and wood is presented. The derivation of the model is based on mass conservation for a mixture containing a vapour phase and an adsorbed water phase embedded in a porous solid material. The principle of virtual moisture concentrations in conjunction with a consistent linearization procedure is used to produce the iterative finite element equations. A monolithic solution strategy is chosen in order to solve the coupled non-symmetric equation system. A model for the development of higher order sorption hysteresis is also developed. The model is capable of describing cyclic hardening as well as cyclic softening of the equilibrium water concentration. The model is verified by comparison with the measured response to natural variations in temperature and humidity. A close agreement of the simulated results to measured data is found. Copyright © 2005 John Wiley & Sons, Ltd. [source] Effects of coupling agents on the oxidation and darkening of cellulosic materials used as reinforcements for thermoplastic matrices in compositesPOLYMER ENGINEERING & SCIENCE, Issue 2 2000J. Martínez Urreaga Oxidation and darkening occur during the processing of composites made from thermoplastic matrices and cellulosic reinforcements. We have studied the effects of several coupling agents on both the oxidation and darkening of cellulosic materials at temperatures close to those used in the processing of cellulose-reinforced thermoplastics. A maleated polypropylene wax (Epolene E-43TM) and two silanes (N-2-aminoethyl-3-aminopropyltrimethoxy silane and methyltrimethoxysilane) were used as coupling agents. Oxidation was measured by Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy. Standard colorimetry was used to measure darkening. Coupling agent effects depend on the nature and extent of cellulose modification achieved by treatments and the nature of the coupling agent. Epolene wax E-43 produced scarce effects on both the oxidation and darkening of cellulosic materials at 200°C. Only for longer oxidation times was an increase in oxidation and darkening observed in E-43-treated samples. Silane coupling agents inhibited the formation of carbonyl and carboxyl groups for shorter oxidation times. The diaminosilane produced a stronger darkening, probably due to a chemical reaction that generated new chromophores containing CN bonds. [source] Methodological analysis for determination of enzymatic digestibility of cellulosic materialsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2007Y.-H. Percival Zhang Abstract Accurate measurement of enzymatic cellulose digestibility (X) is important in evaluating the efficiency of lignocellulose pretreatment technologies, assessing the performance of reconstituted cellulase mixtures, and conducting economic analysis for biorefinery processes. We analyzed the effect of sugars contained in enzymes solutions, usually added as a preservative, and random measurement errors on the accuracy of X calculated by various methods. The analysis suggests that exogenous sugars at levels measured in several commercial enzyme preparations significantly bias the results and that this error should be minimized by accounting for these sugars in the calculation of X. Additionally, a method of calculating X equating the ratio of the soluble glucose equivalent in the liquid phase after hydrolysis to the sum of the soluble glucose equivalent in the liquid phase and the insoluble glucose equivalent in the residual solid after hydrolysis was found to be the most accurate, particularly at high conversion levels (>ca. 50%). Biotechnol. Bioeng. 2007;96: 188,194. © 2006 Wiley Periodicals, Inc. [source] Fast enzymatic saccharification of switchgrass after pretreatment with ionic liquidsBIOTECHNOLOGY PROGRESS, Issue 1 2010Hua Zhao Abstract The pretreatment of cellulose using ionic liquids (ILs) has been shown to be an effective method for improving the enzymatic hydrolysis of cellulose; this technique affords a fast and complete saccharification of cellulose into reducing sugars (Dadi et al., Biotechnol Bioeng. 2006; 95:904,910; Liu and Chen, Chinese Sci Bull. 2006; 51:2432,2436; Zhao et al., J Biotechnol. 2009; 139:47,54). Motivated by these advances, this study examines the effect of IL-pretreatment on the enzymatic hydrolysis of purified xylan (as a model system of hemicellulose) and switchgrass (as a real lignocellulose). The IL-pretreatment resulted in no improvement in the hydrolysis of xylan. The likely reason is that pure xylan has a low degree of polymerization (DP), and is readily biodegraded even without any pretreatment. However, in real cellulosic materials (such as switchgrass), xylan is entrapped within the cellulosic matrix, and cannot be conveniently accessed by enzymes. Our data demonstrate that the IL-pretreatment of switchgrass significantly improved the enzymatic saccharification of both cellulose (96% D -glucose yield in 24 h) and xylan (63% D -xylose yield in 24 h). The compositional analysis of switchgrass suggests a lower lignin content after IL-pretreatment. In addition, the infrared spectrum of regenerated switchgrass indicates a lower substrate crystallinity, whereas the enzyme adsorption isotherm further implies that the regenerated substrate is more accessible to enzymes. This study has further confirmed that IL-pretreatment is an effective tool in enhancing the enzymatic hydrolysis of cellulosic biomass, and allowing a more complete saccharification. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Development of a Novel Whey Beverage by Fermentation with Kefir Granules.BIOTECHNOLOGY PROGRESS, Issue 4 2004Effect of Various Treatments The development of a novel whey-based beverage with acceptable organoleptic properties is reported, where various treatments were studied. Kefir yeast immobilized on delignified cellulosic materials (DCM) or gluten pellets proved to accelerate whey fermentation significantly, with the latter support being not so preferable. Kefir granules seemed to achieve similar fermentation times as DCM. The final pH of the product is suggested to be 4.1 since the profile of the volatile byproducts was higher than other pH values tested. The addition of fructose seemed to be beneficial on the volatile content of the product, although its acceptability as determined by a preference panel was similar to that of the control. Finally, black raisin extract appeared to promote fermentation without any positive effect on the preference of the evaluators. [source] Subcritical Water Reaction Behavior of D -Glucose as a Model Compound for Biomass Using Two Different Continuous-Flow Reactor ConfigurationsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 4 2009T. Saito Abstract Recently, cellulosic materials have been considered as a useful resource for the recovery of valuable chemicals and liquid fuels, etc. Cellulose is a homopolymer of D -glucose, which is often used as a model compound for biomass. Reactions of D -glucose in subcritical water as the reaction solvent were conducted using a single-flow-type reactor (S1) and an admixture-type reactor with feed and preheated-water flow (S2) at temperatures from 200 to 240,°C, pressures from 15 to 20 MPa, residence times from 40 to 120 s, and initial feed concentrations of 1.5,10 wt %. D -Glucose was converted into aldehydes, organic acids and furans, with mainly organic acids obtained at 240,°C. D -Glucose decomposition using reactors S1 and S2 revealed that the conversion rate of D -glucose was promoted more using S2 than by S1. The yield of furans with S1 was higher than with S2, while the yield of organic acids from S1 was lower than that from S2. [source] | |||||||||||||