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941.
Brazil has launched the PROINFA program, a regulatory mechanism to incentivize renewable electricity generation. In the light of this new framework, the best economical option for cogeneration was analyzed using one of the biomass resources available in Brazil-Babassu. Thus not only the possible power production but also the potential of such a regulatory tool to enhance the electricity production based on this biomass source, was analyzed. The power production was based on a steam power cycle cogeneration technology within the Babassu palm oil extraction industry in Brazil (Orbignya ssp. (Palmae)). Was used as base for this study: the energetic matrix for the oil extraction plants (for the two main profiles: oil extraction and refining only, and greater vertical integration with the production of other associated products obtained from the Babassu palm oil), utilization of an extraction–condensation turbine, and steam production operating at three levels of temperature and pressure (2.06 MPa/350 °C, 4.56 MPa/420 °C and 6.2 MPa/450 °C). To analyze the economic performance, the framework drawn up by the PROINFA was taken. From the analysis, the best economical/technical option for the design of the cogeneration system was found to be in industrial units with extraction and treatment of crude Babassu oil—steam generation at 4.56 MPa and 420 °C and, for units with a more vertically integrated production scheme—steam generated at 6.2 MPa and 450 °C. As a result, it became clear that the given framework may help the development of new renewable energy sources, but it does not give the necessary threshold to start new projects, neither does it incentive the maximization of the power production for this specific biomass resource. 相似文献
942.
Production of hydrogen using aluminum and aluminum alloys with aqueous alkaline solutions is studied. This process is based on aluminum corrosion, consuming only water and aluminum which are cheaper raw materials than other compounds used for in situ hydrogen generation, such as chemical hydrides. In principle, this method does not consume alkali because the aluminate salts produced in the hydrogen generation undergo a decomposition reaction that regenerates the alkali. As a consequence, this process could be a feasible alternative for hydrogen production to supply fuel cells. Preliminary results showed that an increase of base concentration and working solution temperature produced an increase of hydrogen production rate using pure aluminum. Furthermore, an improvement of hydrogen production rates and yields was observed varying aluminum alloys composition and increasing their reactive surface, with interesting results for Al/Si and Al/Co alloys. The development of this idea could improve yields and reduce costs in power units based on fuel cells which use hydrides as raw material for hydrogen production. 相似文献
943.
Tomas Herraiz Guillermo Reglero Pedro J Martin-Alvarez Marta Herraiz Maria D Cabezudo 《Journal of the science of food and agriculture》1991,55(1):103-116
Aroma components of ine resulting from fermentation of grape must from the Verdejo cultivar ere isolated by continuous liquid-liquid extraction and further fractionation on a silica gel column. One hundred and thirty-to substances, including alcohols, esters, carbonyl compounds, terpenes, acids and sulphur compounds, ere identified by using GC-MS; some had not been previously detected in ines. Data are given hich could lead to the characterisation of the Verdejo cultivar and the effect of the elaboration of young ines. The sensory contribution of some volatile compounds to the flavour of Verdejo ine is also studied. 相似文献
944.
由于景观起源、物理环境条件和社会经济发展的差异,在南北半球,学术界对城市生物多样性及其与生态设计方法的相互作用有着不同的理解。数千年来,澳大利亚本土植物群落在这片大陆繁衍生息,形成了生物多样性极高的独特景观。植物园融合自然和人造元素,具有科研和保育功能,其设计与规划反映了科学知识随时间变化的动态特征,也为研究不同社会群体在过去如何利用和重视植物提供了的独特视角,植物园的生态设计方法反映了重视和保护生物多样性的新愿景。以澳大利亚为例,研究并回顾了植物园在保护生物多样性方面的益处,讨论了为展示生物多样性植物园设计重点的变化,分析了澳大利亚植物园的设计历史、澳大利亚本土生物多样性以及以生物多样性为重点的设计解决方案。为了解澳大利亚当地生物多样性和制定植物园示范保护与策略提供研究框架,为重新思考和加强植物园设计中的"生物多样性"提供新视角。 相似文献
945.
Boris F. Belokopytov Kestutis S. Laurinavichius Tatyana V. Laurinavichene Maria L. Ghirardi Michael Seibert Anatoly A. Tsygankov 《International Journal of Hydrogen Energy》2009
Eight natural microbial consortia collected from different sites were tested for dark, hydrogen production during starch degradation. The most active consortium was from silo pit liquid under mesophilic (37 °C) conditions. The fermentation medium for this consortium was optimized (Fe, NH4+, phosphates, peptone, and starch content) for both dark fermentation and for subsequent purple photosynthetic bacterial H2 photoproduction [Laurinavichene TV, Tekucheva DN, Laurinavichius KS, Ghirardi ML, Seibert M, Tsygankov AA. Towards the integration of dark and photo fermentative waste treatment. 1. Hydrogen photoproduction by purple bacterium Rhodobacter capsulatus using potential products of starch fermentation. Int J Hydrogen Energy 2008;33(23):7020–26], in the presence of the spent dark, fermentation effluent. The addition of Zn (10 mg L−1), as a methanogenesis inhibitor that does not inhibit purple bacteria at this concentration, also did not inhibit dark, fermentative H2 production. The influence of various fermentation end products at different concentrations (up to 30 g L−1) on dark, H2 production was also examined. Added lactate stimulated, but added isobutyrate and butanol strongly inhibited gas production. Under optimal conditions the fermentation of starch (30 g L−1) resulted in 5.7 L H2 L−1 of culture (1.6 mol H2 per mole of hexose) with the co-production mainly of butyrate and acetate. 相似文献
946.
Maria Albareda-Sambola Elena Fernández Gilbert Laporte 《Computers & Operations Research》2009,36(2):597-611
This article introduces a new problem called the Capacity and Distance Constrained Plant Location Problem. It is an extension of the discrete capacitated plant location problem, where the customers assigned to each plant have to be packed in groups that will be served by one vehicle each. The constraints include two types of capacity. On the one hand plants are capacitated, and the demands of the customers are indivisible. On the other hand, the total distance traveled by each vehicle to serve its assigned customers in round trips plant–customer–plant is also limited. The paper addresses different modeling aspects of the problem. It describes a tabu search algorithm for its solution. Extensive computational tests indicate that the proposed heuristic consistently yields optimal or near-optimal solutions. 相似文献
947.
Daniella Regina Mulinari Herman J.C. Voorwald Maria Odila H. Cioffi Maria Lúcia C.P. da Silva Tessie Gouvêa da Cruz Clodoaldo Saron 《Composites Science and Technology》2009
Natural fibers used in this study were both pre-treated and modified residues from sugarcane bagasse. Polymer of high density polyethylene (HDPE) was employed as matrix in to composites, which were produced by mixing high density polyethylene with cellulose (10%) and Cell/ZrO2·nH2O (10%), using an extruder and hydraulic press. Tensile tests showed that the Cell/ZrO2·nH2O (10%)/HDPE composites present better tensile strength than cellulose (10%)/HDPE composites. Cellulose agglomerations were responsible for poor adhesion between fiber and matrix in cellulose (10%)/HDPE composites. HDPE/natural fibers composites showed also lower tensile strength in comparison to the polymer. The increase in Young’s modulus is associated to fibers reinforcement. SEM analysis showed that the cellulose fibers insertion in the matrix caused an increase of defects, which were reduced when modified cellulose fibers were used. 相似文献
948.
Modification of vermiculite by polymerization and carbonization of glycerol to produce highly efficient materials for oil removal 总被引:2,自引:0,他引:2
Miguel de Araújo Medeiros Maria T.C. Sansiviero Maria Helena Araújo Rochel Montero Lago 《Applied Clay Science》2009,45(4):213-219
Impregnation and reaction of glycerol (Gly) on the surface of expanded vermiculite (EV) was used to produce a highly efficient absorbent to remove water spilled oils. The vermiculite was impregnated by glycerol containing 1, 2 and 4 mol% of H2SO4 at EV/Gly ratios, i.e. 1/1, 1/2 and 1/3, and heated to 380, 580 and 750 °C. SEM, TG, BET specific surface area, and Raman analyses indicated that glycerol at 380 °C forms a polymer layer. At higher temperatures, the polymer decomposed to form porous carbon covering the EV surface. These materials were investigated for the removal of three different oils, i.e. diesel, soybean and engine oil spilled on water. The obtained results showed a remarkable increase on oil removal of 600% compared to the non-modified EV. 相似文献
949.
950.
Some ideas relevant to the prevailing viscoelasticity interpretations of dynamic mechanical thermal analysis (DMTA) experiments
are presented. The main aspect is the inclusion of kinetic energy and inertia as variables, seeing the relaxing mass constantly
increasing during strain, assigning inertial variation and not viscosity to energy dissipation. The equations developed make
it possible to obtain the values of important viscoelastic properties, under in any experimental condition, with the data
taken from previous experiments. 相似文献