915 resultados para WOOD FIBERS


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Engenharia Mecânica - FEG

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Recycled polymer matrix composites reinforced with wood flour can be a viable alternative for the replacement of wood and virgin polymers in materials used in floors, door frames, windows and external cladding. The objective of this research was to determine some physical and mechanical parameters of composite made with Pinus taeda and elliottii wood flour (WF) and recycled polypropylene (PP), without the use of compatibilizers or additives. The composites were separated into four traits, namely 100% PP, 90% PP with 10%, WF 80% PP with 20% WF and 70 % PP with 30% WF. The characterization of the composite followed the standards ASTM D-638-10, ASTM D256-00, ASTM D570 -98, ASTM D1238 -10 and ASTM G 155-05, it was also employed the surface analysis by scanning electron microscopy. The dimensional stability tests showed satisfactory results. Even the composite with a higher percentage of wood flour (30%) had a flow index of 10 MFI, considered compatible with that observed for PP (polypropylene) virgin by standard ASTM D 1238-10. The inclusion of wood flour (FM) afforded composites with good mechanical characteristics which can be applied in manufacture of different materials, specifically employed outdoors.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Products derived from wood or engineered products are becoming interesting alternatives to the replacement of solid wood in various applications, from structural components to the furniture industry and packaging. Among these products, there are panels built by strands, particles and fibers, each one having their particular characteristics and potential of use. Since the different types of panels are produced, waste generation is part of the process, and that more technological it is, it still generates losses of raw materials. Based on the need for rational use of raw materials and using almost full of industrially processed wood, It arises the proposal of this work, which seeks to use waste from the lamination, like pieces of strands, broken strands, strands rough, cracked strands to produce panels with structural characteristics of the OSL panel (Oriented Strand Lumber), LSL (Laminated Strand Lumber) and OSB (Oriented Strand Lumber). Besides the use of waste, this paper seeks an alternative to the use of the adhesive, because the industry uses formaldehyde-based adhesives, which over the press, they emit large amounts of formaldehyde, which is very aggressive to humans and environment. The panels made with polyurethane resin based on castor oil and hot-pressed were characterized by physical and mechanical tests according to specifications of European Standard (EN). High values of tensile strength, elastic modulus and density were found in the results of tests. Adding to stable values of swelling and moisture content, the panel studied adds attractive features to the panel market, especially in the civil construction

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The need for housing in Brazil is very large, and despite government efforts to address this issue, the housing deficit is too large. When analyzing markets without this problem, it is concluded that one of the factors that influence this model is the construction adopted by Brazilian society that is in masonry. Alternatively, the system can be used in constructive Wood-frame. To apply this system in Brazil, one can say that the workmanship and the materials available to meet the demand would be created in a short period of adjustments and capabilities, but identifies himself as one of the biggest problems the planning and management of works. And one of the tools for solving this problem is to use a checklist of the activities of constructive process, avoiding forgetting or not aware of the activities necessary to complete the project

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The process of sanding wood is little known and industries use it in a practical way without having studied their best conditions before. There are few studies involving this type of machining. On this basis, this paper studied the effects of varying moisture content of the wood surface quality after the sanding process. It was used a sanding machine with flat horizontal cut parallel to the fibers, using: 02 different species (Pinus elliottii and Corymbia citriodora); 01 sanding abrasive (aluminum oxide) and 03 different particle size abrasives ( P80 , P100 and P120 ) . Initially, the pieces were acclimatized ( 2 ± 7% , 12% and 17% ± 2 ± 2 ) and subsequently passed by the sanding process, and therefore, the surface roughness was analyzed. For each condition, were performed 06 repetitions totaling 54 trials for each species. We analyzed the effects of wood moisture by capturing the power sanding, rougheness, acoustic emission and maximum temperature during the sanding process. The variation of moisture content produced changes in the surface quality of the finished parts, and these changes were more marked in Pinus than Corymbia. During the sanding process of the specimens with 7 % and 12 % humidity, there was a lower noise emission, power consumption and heating surface. When checking the roughness of these parts after this process, it was observed that the surface quality of them were superior in the parts sanded containing 17 % moisture

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In the last years, the use of industrialized systems of lattice structures of wood as an alternative in the construction processes, is becoming more popular in Brazil, mainly for their commitment to the environment.The industrialized system of wooden lattice structures consists in a production of lattice structures, composed of pieces of wood where their mechanical connections are made with the sheet multi-toothed connectors (CDE).Among the many challenges to make this system competitive, the whole system of the connections between the pieces of wood not only must show functionality, but also speed, strength, versatility and economy. Referenced at Brazilian Standard for Wood Structures (NBR 7190/1997 - Project of timber structures) the sheet multi-toothed connectors, are analyzed using three test methods: tensile strength parallel to grain, tensile strength normal to the fibers and shear strength, all of them in two positions, αCH0=0o e αCH0=90o to four types of wood: Angelim (Vatairea heteroptera Ducke); Red-Angico (Parapiptadenia rigida (Benth) Brenae); Garapa (Apuleia leiocarpa (Vog.) Macbr) and Jatoba (Hymenaea stilbocarpa Hayne), belonging to the Leguminosae family and founded in several regions of Brazil.The purpose of this manuscript consists to analyze the mechanical connections with the sheet multi-toothed connectors through tests from NBR7190/1997

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O presente trabalho consiste em demonstrar valores referentes ao conforto ambiental de dois modelos construtivos, sendo o primeiro um edifício já executado e o outro em fase de implantação, ambos no Campus Experimental de Itapeva, aplicando alguns conceitos em habitação mais sustentáveis de madeira na região de Itapeva, estado de São Paulo, Brasil. A edificação construída sedia duas salas de aula a partir da tipologia construtiva wood frame, constituída basicamente de paredes autoportantes compostas de ossatura de madeira tratada de pinus.sp, chapas estruturais em OSB, manta de isolamento térmico/acústico e fechamento interno e externo, respectivamente em gesso e sidding (lambris de madeira). A habitação em fase de início de implantação foi idealizada a partir da tipologia construtiva log-home, e atenderá a necessidade de espaço físico para abrigar o Centro Acadêmico e a empresa-júnior “PROMAD”, ambos do curso de Engenharia Industrial Madeireira do Campus Experimental da UNESP/Itapeva. Esta construção foi elaborada a partir de técnicas de baixo impacto ambiental, levando em consideração os resultados de análise térmica obtidos na edificação anterior. Em ambos modelos construtivos foram empregados recursos renováveis abundantes na região, como a madeira de reflorestamento de Pinus e de Eucalipto. Foi acrescentado ainda ao segundo modelo a utilização de resíduos industriais lignocelulósicos, como rolete de laminação e outros materiais locais disponíveis. A metodologia básica empregada para a obtenção de dados sobre o conforto térmico em relação as edificações foi, para o primeiro caso, a coleta de dados de temperatura e umidade utilizando um termo-higrômetro, a sistematização e análise de dados reais obtidos no interior da edificação. No segundo caso, o dimensionamento do conforto térmico... (Resumo completo, clicar acesso eletrônico abaixo)

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Pós-graduação em Ciência Florestal - FCA

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Pós-graduação em Engenharia Mecânica - FEG

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Design tools have existed for decades for standard step-index fibers, with analytical expressions for cutoff conditions as a function of core size, refractive indexes, and wavelength. We present analytical expressions for cutoff conditions for fibers with a ring-shaped propagation region. We validate our analytical expressions against numerical solutions, as well as via asymptotic analysis yielding the existing solutions for standard step-index fiber. We demonstrate the utility of our solutions for optimizing fibers supporting specific eigenmode behaviors of interest for spatial division multiplexing. In particular, we address large mode separation for orbital angular momentum modes and fibers supporting only modes with a single intensity ring.