Thermoplastic composites using natural fibres are studied intensively and widely used in applications including automotive, packaging, consumer goods and construction. Good balance of mechanical properties, processability and low cost are great advantages of these materials on top of the environmental benefits. Recently, there have been various efforts to amplify the positive effects on the environment by replacing the conventional polymers by bio-derived renewable polymers in the composites. Recent studies conducted from our research group showed competitiveness of plant fibre-thermoplastic composites. Implementing the promising results and experience, a new composite design using renewable polyethylene as the matrix material was studied. This polyethylene is a renewable thermoplastic that was derived from sugar cane ethanol. The objectives of this study were to employ renewable high density polyethylene (HDPE) into composites using wheat straw and flax fibre to extend the range of properties of the HDPE while keeping the amount of renewable content to nearly 100%. The chemical resistance of these materials has not been reported before and it was investigated here by measuring and comparing the properties before and after accelerated chemical ageing. Both wheat straw and flax fibre had two different grades in size. Each of them was compounded with HDPE and additives (antioxidant and coupling agent) in a co-rotating twin screw extruder. The concentrations of fibres were varied from 0 to 30 wt-%. Then, injection molded samples were prepared for measurement of properties: tensile, flexural, impact tests. The effects of reinforcing fibre size were studied first. Both length and aspect ratio were considered. For both types of fibre composites, a general trend was observed. There was no clear evidence of improvements in flexural (strength and modulus) and tensile (strength, percentage elongation at break) properties with respect to the change in fibre size. However, impact (IZOD impact strength, Gardner impact failure energy) properties showed some improvements. This result was due to no substantial difference in size and aspect ratios in post-processed fibres that were actually residing in the matrix. There were remarkable improvements in flexural strength and modulus when the fibre content increased. However, minor decreases in tensile properties were observed. Furthermore, the impact properties were very sensitive to the concentration of fibres. As the fibre concentration went up, there were significant decreases in both IZOD impact strength and Gardner impact failure energy. Chemical resistance of these composites was studied by exposing them in six different chemical solutions (hydrochloric acid, acetic acid, sodium hydroxide, ethyl alcohol, industrial detergent, water) for up to thirty days. The increase in weight and leaching behaviour was observed. As the fibre content increased within the composites, the weight gain was more rapid during chemical ageing. Because there were more fibres exposed on the surface after chemical ageing, it is likely that they contributed to the higher flux of liquids (used for chemical ageing) inside the sample. Among the physical properties, tensile properties were most susceptible to the chemical ageing. One possible reason could be due to the exposed surface area to volume ratio, which was the highest in tensile bars and therefore faster mass transfer taking place into the matrix per volume. Finally, morphological study using scanned electron spectroscopy (SEM) revealed the damage on the surface when exposed to the chemicals. The fibres on the surface had been leached out in the sodium hydroxide solution leaving empty spaces. The fractured surface was also monitored via SEM. Though there was not enough evidence of strong interfacial interactions between the fibre and the polymer, good dispersions were observed.

Bibliography: leaves 134-148. / xi, 148 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The objectives of this study are to determine if and how inorganic matrices influence organic matter decomposition with particular emphasis on the biochemical changes which occur as decomposition progresses. The influence of inorganic matrices (sand, sand + kaolin and loamy sand) on the decomposition of straw and Eucalyptus litter during incubations was followed by various chemical and spectroscopic methods to aid in the understanding of the mechanism of physical protection of organic matter in soils. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1997

Leucaena leucocephala and Sesbania sesban in dry form were fed as supplements to goats feeding on a low quality basal diet of barley straw. Each browse supplement was fed at four levels: 0 %, 0.83 % liveweight (LW), 1.66 % LW and at ad libitum. The intakes of dry matter (DM) and organic matter (OM), DM and OM digestibility, nitrogen (N) digestibility and balance, and liveweight gain were evaluated during a 5 week trial. For goats offered both leucaena and sesbania there was no significant (p<0.05) difference in DM or OM intakes between 0.83 % LW and 1.66 % LW levels of browse supplementation. When both lecaena and sesbania were offered ad libitum the DM and OM intakes were significantly (p<0.05) lower than for either 0.83 % LW or 1.66 % LW level of supplementation. Feeding both leucaena and sesbania increased the DM and OM digestibility coefficients significantly over thos of the controls. The growth rates for goats supplemented with leucaena at various levels were not significantly different from each other. For the goats offered sesbania at ad libitum, their growth rates were significantly lower than for those fed sesbania at either 0.83 % LW or 1.66 % LW. The apparent digestibility of nitrogen (ADN) was not significantly different among leucaena supplemented treatments. For goats offered sesbania, the ADN was significantly higher than for the controls. The ability of browse supplements to increase intakes and digestibility of both dry matter and organic matter is discussed.

Thesis (M.S.)--University of Texas at El Paso, 2007. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M. App. Sc.)--University of Adelaide, Dept. of Animal Science, 1995? / Copies of the author's previously published articles inserted. Includes bibliographical references (leaves 142-159).

Thesis (M.S.)--University of California, Davis, 2007. / Text document in PDF format. Title from PDF title page (viewed on August 28, 2009). "Received by ITS-Davis: September 2007"--Publication detail webpage. Includes bibliographical references (p. 114-116).

Orientador: Maria Aparecida Anselmo Tarsitano / Banca: Élcio Hiroyoshi Yano / Banca: Maura Seiko Tsutsui Esperancini / Resumo: O presente trabalho teve como objetivo realizar um estudo que quantificasse o impacto gerado pelo transporte da palha para a indústria no dimensionamento da frota, no valor dos investimentos iniciais para aquisição dos equipamentos do corte, carregamento e transporte (CCT) mecanizados da cana-de-açúcar picada sem queima e na viabilidade econômica dessas operações. Os estudos foram conduzidos em parceria com uma empresa do setor sucroalcooleiro localizada na região Oeste do Estado de São Paulo, durante os anos de 2007 e 2008. A metodologia proposta foi composta pelo acompanhamento das atividades rotineiras da empresa, visando à obtenção de dados reais de campo. Os equipamentos utilizados nas operações foram divididos em sistemas: corte mecânico, carregamento, transporte e apoio. Se for opção da empresa a colheita integral da cana-de-açúcar sem a separação da palha do colmo no campo, os equipamentos industriais deverão ser adequados para a realização da separação da palha do colmo a seco. Ao se simular os dois tipos de colheita mecanizada (com e sem palha) se obtêm duas configurações diferentes para a quantidade de ART perdido com acréscimo de palha na moagem, assim como quantidades diferentes de geração de energia para venda. Para a análise de viabilidade econômica dos dois sistemas estudados, foi estruturado um fluxo de caixa, onde é possível verificar os valores das entradas e saídas dos recursos e produtos. Os resultados mostram que a presença da palha interfere no dimensionamento dos equipamentos envolvidos do CCT, fazendo assim, com que os investimentos sejam diferentes. O custo operacional total (COT) em R$/hectare também foi mais oneroso no sistema em que não se separa a palha dos colmos devido à redução na capacidade de campo. O aumento do potencial de exportação de energia elétrica, devido à presença da palha na indústria, faz com que ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study had the goal to quantify the impact generated by the transport of straw to factory in the fleet sizing, value of initial investments for equipment purchase involved in cut, loading and transportation (CCT) mechanized of chopped sugarcane without burning and in the economic viability of these operations. The studies were conducted in partnership with a company located in Western part of São Paulo State, during the years 2007 and 2008. The proposed methodology was composed of monitoring the daily activities of this company, aiming at collecting real field data. The equipment used in operations were divided into systems: mechanical cutting, loading, transportation and support. If the company chose the sugarcane harvesting without separating the straw in the field, the industrial equipment expected to change. By simulating the two types of mechanical harvesting (with and without straw) gets two different settings for the amount of lost ART with straw increase in the crushing, as well different amounts of power generation for sale. For the analysis of economic feasibility of the two systems studied, was structured cash flow, where it‟s possible checking the values of inputs and outputs of resources and products. The results showed that the presence of straw interferes in the equipment sizing involved in the CCT, making the investments different. The total operational cost (COT) in R$/hectare was also more expensive in the system that does not separate the straw due to the reduction in the field capacity. The increase in the export potential of electricity, due to the presence of straw in the factory, makes this system feasible, thus covering the difference found between the investment and the operational costs / Mestre

Esta Tese traz reflexões sobre processos de produção audiovisual, defendendo a ideia de que essa produção organizada por professores em formação, em relação dialógica com o contexto no qual estão inseridos, interligando as imagens a diferentes aspectos, poderia levar os sujeitos envolvidos nos processos de ensino e aprendizagem ao reconhecimento do valor coletivo dessas práticas. O enfoque principal são os processos de produção audiovisual de professores em formação em Arte, delimitado neste estudo pelo contexto das tramas ecológicas, como um contexto propício a levar à instauração de diálogos, ampliação de campos de referência e produção de sentidos. A interação com as mídias digitais, disponibilizadas no campo educacional, surgem como ferramentas na construção do conhecimento que possibilitam reflexões sobre os processos éticos, estéticos e novos possíveis. O pensamento complexo, possibilitado por um olhar que dialoga com o contexto em que se está inserido e pela interligação de saberes como proposto por Morin, permitiu identificar processos de produção audiovisual, possibilitados por modos de organização e estratégias, através de interações com o meio e com atores sociais, caracterizados por retroações e recursividade que levam à interligação de diferentes conhecimentos. Para análise desses processos foi considerado o dialogismo de Bakthin que gerou os conceitos de polifonia, exotopia e cronotopia, que evidenciam aspectos das várias vozes, tempo e espaço da relação dialógica e atribuição de sentidos à obra criada/observada. A metodologia dessa análise de processos de produção audiovisual dos sujeitos é qualitativa e desenvolveu-se em uma abordagem de pesquisaparticipante, sugerida por Brandão e Borges (2007), que levam em consideração o conhecer, o pensar e o intervir, a exploração da comunidade, a identificação das necessidades básicas e a elaboração de estratégia educativa. Foi considerado ainda a Pedagogia da Autonomia de Freire (2002), no que se refere à escuta das narrativas dos participantes sobre suas experiências cotidianas, entendidas neste estudo, como fator preponderante à pesquisa. Dessa forma, os processos analisados dizem respeito ao resultado de diferentes atividades audiovisuais vivenciadas por professores em formação em Arte e artesãos, produtores de tramas ecológicas ou objetos em fibras vegetais, com diferentes faixas etárias, e restringem-se especificamente aos registros fotográficos e videográficos sobre o processo artesanal desses objetos, interrelacionados ou não aos aspectos culturais e educacionais que envolvem esse fazer. Esses resultados apontam para a importância do desenvolvimento de um olhar dialógico, possibilitado pela interação com as mídias de seu tempo na construção do conhecimento. / This dissertation reflects on audiovisual production processes, defending the idea that this production organized by teachersing training, on a dialogic relation to with context in which they are inserted, linking images to different aspects, could lead the individuals involved in teaching and learning processes to recognize the collective value of these practices. The main focus are the audiovisual production processes of teachers training in art, defined in this study by the context of ecological braided straw, as an enabling environment for the establishment of dialogue, expansion of reference fields and production of meanings as a context conducive to lead to the establishment of dialogue, expansion of reference fields and production of meanings. The interaction with digital media, available in the educational field, appear as tools in the construction of knowledge ethical, aesthetic and possible new processes. Complex thinking, made possible by a look that speaks to the context in which it is inserted and the interconnection of knowledge, as proposed by Morin, identified audiovisual production processes, possible by organizational methods and strategies, through interactions with the environment and with social actors characterized by retroactions and recursion that lead to the interconnection of different knowledge. The analysis of these processes were based on Bakhtin's dialogism and the concepts of polyphony, exotopy and chronotope with the evidence of various voices, time and space of dialogical relationship and attribution of meaning on the work done/observed. The methodology of this analysis of audiovisual production processes of the subject is qualitative and has developed into a research-participant approach, suggested by Brandão and Borges (2007), which take into account the knowledge, thought and action, the exploitation of community, identification of basic needs and the development of educational strategy. It was still considered the Pedagogy of Autonomy Freire (2002), with regard to listening to the narratives of the participants about their everyday experiences, understood in this study as a major factor research. Thus, the processes analyzed concern the result of different audiovisual activities experienced by teachers in training in Art and artisans, producers of ecological braided straw or objects in vegetable fibers, different age groups, and they are limited specifically to photographic records and videographic on the handmade process of these objects, inter-related or not to the cultural and educational aspects involved in this action. These results point to the importance of developing a dialogical look, made possible by the interaction with the media of their time in the construction of knowledge.

Este trabalho tem como objetivo analisar a influencia da configuração física do sistema de espalhamento de palha em colheitadeira de grãos na eficiência do espalhamento da palha, visando cobertura mais uniforme do solo de cultivo. Tal processo produzirá melhoramentos no próximo plantio, pois espalhamento mais uniforme de palha evita perdas de nutrientes do solo por incidência luz solar, assim como previne erosão hídrica e eólica. Para analisar a influencia dos parâmetros da configuração física do sistema espalhador de palha foram realizados testes alterando parâmetros como quantidade de pás, ângulo de pás, rotação dos rotores, diâmetro dos rotores, defletor central e vazão de material. Devido à importância econômica no cenário nacional e mundial, utilizou-se a cultura de soja e os testes foram realizados em laboratório seguindo as normas da Sociedade Americana de Engenheiros Agrícolas e Biológicos (ASAE). O trabalho visa fornecer dados que auxiliem designers no desenvolvimento de novos projetos de gerenciamento de resíduos, de modo que venham a aumentar a eficiência desses sistemas, contribuindo com o crescimento da agricultura em no país. Os resultados apontam que a geometria do defletor central apresenta o parâmetro de maior influencia na uniformidade de cobertura da palha ao solo. / The objective of this work is to analyze the influence of the physical configuration of the straw spread system in grain harvester on the efficiency of the straw spread, aiming at a more uniform coverage of the crop soil. This process will produce improvements in the next planting, because more uniform straw spread prevents soil nutrient losses by sunlight, as well as prevent water and wind erosion. In order to analyze the influence of the parameters of the physical configuration of the straw spreader system, tests were performed changing parameters such as blade quantity, blade angle, rotor rotation, rotor diameter, central deflector and material flow. Due to the economic importance in the national and world scenario, the soybean crop was used and the tests were carried out in laboratory according to the standards of the American Society of Agricultural and Biological Engineers (ASAE). The work aims to provide data to assist designers in the development of new waste management projects, so that they will increase the efficiency of these systems, contributing to the growth of agriculture in the country. The results indicate that the geometry of the central baffle presents the parameter of greatest influence on the uniformity of covering of the straw to the soil.

Many agricultural biogas stations process predominantly phytomass specifically grown for power engineering purposes as a primary raw material. This results in gradual increase of maize proportion in sowing sequences at the exclusion of traditional area-specific crops, which presents various potential negative effects. The aim of study is to evaluate the substitution of maize with wheat straw in the anaerobic fermentation process from the biotechnological and economic viewpoint. For this purpose, wheat straw pellets were pretreated using the high-pressure extruder in compliance with UV CZ 21314 at different runtime parameters. Cumulative methane (CH4) production in quarter-mode operation simulation, based on the extrusion pressure, cycle duration and fermentation temperature, was the main evaluation criteria. Optimal run time parameters were derived from the approximation ? extrusion pressure 1,35 MPa, reaction time 210 s, in order to achieve maximal CH4 production at mesophilic fermentation temperature (38 °C). For fermentation temperature 48 °C, optimal pressure 1,25 MPa and cycle duration 180 s were approximated. The discount rate of Net Present Value (NPV) was established as a main comparative criterion considering overall executive, legislative and technological aspects of analyzed biological effects. Based on these findings suggest, wheat straw extrusion is interesting, unconventional and profitable technology in the field of biogas production.