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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
391

The Second-Hand Society

Cooke, Christina Elizabeth 01 January 2011 (has links)
The Second-Hand Society tells the stories of people in Portland, Oregon who redefine waste by making use of objects others discard. The author spends time in repair shops watching craftsmen hammer and polish broken typewriters, vacuum cleaners and shoes back to life. She follows book scouts, clothes pickers and liquidators as they gather merchandise to resell and spends hours at nonprofits that collect and redistribute unwanted electronics and building supplies. She watches junk artists and fashion designers assemble found objects into display pieces, accompanies Dumpster divers and "freegans" along their regular collection routes and visits the homeless encampment by the airport to see how an entire community of people survives on nothing but reclaimed materials. The members of the second-hand society challenge the traditional conception of things as "broken" or "unwanted" and assert that forward movement and new-new-new is not always optimal. By examining the motivations and practices of the people who make use of our discards and looking at the contradictions they run up against, this thesis develops a more complete understanding of the reality that's possible if we think differently about our waste.
392

Caractérisation mécanique et thermique de biocomposites à matrice polystyrène recyclé renforcée par des coques de cotonnier (Gossypium Hitsutum L.) ou des particules de bois de Kénaf (Hibiscus Cannabinus L.) / Mechanical and thermal characterization of biocomposite materials at matrix recycled polystyrene reinforced by the hulls of cotton (Gossypium Hirsutum L.) or particles of wood of kénaf (HibIscus Cannabinus L. ).

Soulama, Sagnaba 21 November 2014 (has links)
Dans le contexte actuel marqué par une grande émergence des questions environnementales, de l’économie circulaire et du développement durable, la mise au point d’éco-matériaux représente un enjeu majeur qui offre une alternative aux plastiques recyclés en fin de cycles de vie.L’objectif de ce travail est de contribuer au développement de deux éco-matériaux à partir des biomasses végétales cultivables non alimentaires disponibles, associées à des polymères synthétiques recyclés en fin de cycles de vie.Il s’agit d’une part, de développer un matériau biosourcé constitué de polystyrène recyclé, renforcé de coques de cotonnier. Ce matériau devra être susceptible de se substituer au polystyrène dans des domaines d’applications diverses telles que la fabrication de pièces d’isolation thermique, d’habillage intérieur de voitures, des coques de portables cellulaires, d’ordinateurs, de photocopieurs et d’emballages divers.D’autre part, de développer des panneaux de particules en bois de tiges de cotonnier et de tiges de kénaf associés à un liant naturel (la colle d’os) pour une utilisation dans le domaine de l’isolation thermique d’intérieur en remplacement des panneaux de particules élaborés avec la colle urée formaldéhyde.L’influence des paramètres d’élaboration pour chacun des deux matériaux a été analysée. Après optimisation des conditions de mise en œuvre pour chaque matériau, la tenue mécanique, les propriétés thermiques et la microstructure ont été déterminées et optimisées dans chaque cas. / In the current context marked by a large emergence of environmental issues, the circular economy and sustainable development, the development of eco-materials represents a major challenge which offers an alternative to plastics recycled at end of life cycles.The objective of this work is to contribute to the development of two eco-materials from plant biomass non-cultivable food available, associated with synthetic polymers recycled at end of life cycles.It is a part, to develop a biosourced material constitutes of recycled polystyrene, strengthened of hulls of cotton. This material will be likely to be a substitute for polystyrene in areas of various applications such as the manufacture of parts for thermal insulation, interior trim from cars, the hulls of cellular mobile, computers, photocopiers, and various packaging.On the other hand, to develop particle board in wood of cotton stems and stalks of kenaf associated with a binder natural (the glue of bone) for use in the area of the thermal insulation of interior in replacing the panels of particles prepared with glue urea formaldehyde.The influence of the parameters for the development for each of the two materials was analyzed. After optimization of conditions of implementation for each material, the holding mechanical, thermal properties and the microstructure have been determined and optimized in each case.
393

事業廢棄物產業群聚與跨界網絡之研究 / A Study of Industry Cluster and Trans-border Networks in the Industrial Waste

葉文芝, Yeh,Wen Chih Unknown Date (has links)
本研究主要是以產業群聚、跨界網絡與研發創新觀點,分析廣東省清遠再生銅產業所形塑出之產業群聚現象。在台灣與清遠地區產業制度變遷的發展過程中,跨界與在地網絡的連結不但對清遠地區在地產業內的權力結構產生衝擊,更因此激勵在地事業機構間對研發創新的渴望。 研究結果發現:清遠再生銅產業之群聚現象,除了可歸於中國中央與地方政府的強制規劃外,台灣事業機構提供廢貨源、資訊、技術、經營管理理念與資金於當地,是促進當地產業群聚的重要推手。隨群聚內的事業體系間的相互提攜與擴溢,間接促使產業內結構得以調整,而使在地企業得以改造,更激發出產業升級、研發創新與當地居民向心力的凝聚。跨界網絡融入清遠在地網絡後,因外部知識的潛在價值,更有利於在地事業機構本身的吸收。而台灣與清遠地區事業廢棄物產業的研發創新的出發點是各自獨立的體系,但隨台灣事業機構於清遠地區取得專利後,亦會藉由知識分享或透過支付權利金模式回饋與台灣境內公司,因此台灣與清遠地區事業廢棄物產業在研發創新的道路上漸漸從分壘的平行線轉向分享的交叉線上。 / This study analyzes the industry cluster established by the recycled copper industry in Qingyuan, Guangdong, primarily from the perspective of industry clusters, trans-border networks, and R&D innovation. During the development process of the industrial system transition on Taiwan and Qingyuan Area , connections between trans-border and local networks not only had an impact on domestic industry power structures in Qingyuan Area, but also stimulated a desire for R&D innovation within local enterprises organizations. The results of the study indicate that in addition to attributing the clustering of the recycled copper industry to mandatory plans by the central and local governments in China, Taiwan enterprises provide waste sources, information, technology, management philosophy and funds, is an important promoter to promote local in industry cluster , mutual support and expansion among the industry cluster enterprises systems indirectly prompted internal industry adjustments, resulting in the restructuring of local enterprises, which further inspired industry upgrading, innovation, and cohesiveness among local residents. As trans-border networks gradually blended into Qingyuan Area domestic networks, the potential value from external knowledge was more readily available for local enterprises to absorb. While the starting points of R&D innovation arose from individual systems on Taiwan and Qingyuan Area, benefits could be reaped by enterprises in Taiwan through shared knowledge or paid royalties when trans-border enterprises acquired patents in Qingyuan Area. Therefore, on the road to R&D innovation, industries on Taiwan and Qingyuan Area transformed from following separate, parallel routes to sharing a single route.
394

Desenvolvimento e caracteriza??o de comp?sitos poli(tereftalato de etileno) reciclado (PET reciclado) com flocos de vidro.

Moura, M?rcio Cleto Soares de 29 July 2011 (has links)
Made available in DSpace on 2014-12-17T14:07:07Z (GMT). No. of bitstreams: 1 MarcioCSM_TESE.pdf: 957118 bytes, checksum: 7c10d815ada900ecb0efde8936a6064e (MD5) Previous issue date: 2011-07-29 / The growing concern with the solid residues management, observed in the last decade, due to its huge amount and impact, has motivated the search for recycling processes, where these residues can be reprocessed to generate new products, enlarging the cycle of materials and energy which are present. Among the polymeric residues, there is poly (ethylene terephthalate) (PET). PET is used in food packaging, preferably in the bottling of carbonated beverages. The reintegration of post-consumer PET in half can be considered a productive action mitigation of environmental impacts caused by these wastes and it is done through the preparation of several different products at the origin, i.e. food packaging, with recycling rates increasing to each year. This work focused on the development and characterization mechanical, thermal, thermo-mechanical, dynamic mechanical thermal and morphology of the pure recycled PET and recycled PET composites with glass flakes in the weight fraction of 5%, 10% and 20% processed in a single screw extruder, using the following analytical techniques: thermogravimetry (TG), differential scanning calorimetry (DSC), tensile, Izod impact, Rockwell hardness, Vicat softening temperature, melt flow rate, burn rate, dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). The results of thermal analysis and mechanical properties leading to a positive evaluation, because in the thermograms the addition of glass flakes showed increasing behavior in the initial temperatures of thermal decomposition and melting crystalline, Furthermore was observed growing behavior in the mechanical performance of polymer composites, whose morphological structure was observed by SEM, verifying a good distribution of glass flakes, showing difference orientation in the center and in the surface layer of test body of composites with 10 and 20% of glass flakes. The results of DMTA Tg values of the composites obtained from the peak of tan ? showed little reductions due to poor interfacial adhesion between PET and recycled glass flakes. / A crescente preocupa??o com a gest?o de res?duos s?lidos, observada na ?ltima d?cada, em virtude de sua enorme quantidade e impacto ambiental, tem motivado a busca por processos de reciclagem, onde estes res?duos podem ser reprocessados de modo a gerarem novos produtos, ampliando o ciclo dos materiais e energia neles contidos. Dentre os res?duos polim?ricos, destaca-se o poli(tereftalato de etileno) (PET). O PET ? utilizado em embalagens de alimentos, preferencialmente, no envase de bebidas carbonatadas. A reintegra??o do PET p?s-consumo ao meio produtivo pode ser considerada uma a??o mitigat?ria dos impactos ambientais causados por estes res?duos e j? ? realizada por meio da obten??o de diversos produtos diferentes ao da origem, ou seja, embalagens para alimento, com taxas de reciclagem crescente a cada ano. Este trabalho focou o desenvolvimento e a caracteriza??o mec?nica, t?rmica, termo-mec?nica, termo-din?mico-mec?nica e morfol?gica do PET reciclado processado e dos comp?sitos de PET reciclado com flocos de vidro na fra??o em peso de 5%, 10% e 20% processados em uma extrusora rosca simples, utilizando as seguintes t?cnicas de an?lise: termogravimetria (TG), calorimetria explorat?ria diferencial (DSC), tra??o uniaxial, impacto Izod, dureza Rockwel, temperatura de amolecimento Vicat, ?ndice de fluidez, taxa de queima, an?lise termo-din?mico-mec?nica (DMTA) e microscopia eletr?nica de varredura (MEV). Os resultados das an?lises t?rmicas e das propriedades mec?nicas conduziram a uma avalia??o positiva, pois nos termogramas as adi??es dos flocos de vidro mostraram comportamento crescente nas temperaturas inicial de decomposi??o t?rmica e de fus?o cristalina, al?m disso, observou-se comportamento crescente no desempenho mec?nico dos comp?sitos polim?ricos, cuja estrutura morfol?gica foi observada por MEV, verificando uma boa distribui??o dos flocos de vidro, apresentando diferen?a na orienta??o no centro e na camada superficial do corpo de prova dos comp?sitos com 10 e 20% de flocos de vidro. Nos resultados de DMTA os valores de Tg dos comp?sitos obtidos a partir do pico de tan ?, apresentaram pequenas redu??es, devido a pobre ades?o interfacial entre o PET reciclado e os flocos de vidro.
395

Možnosti využití skelného recyklátu pro přípravu směsných cementů / Possibilities of using recycled glass for the preparation of blended cements

Dobrovolný, Petr January 2015 (has links)
This work focuses on the possibility of using recycled glass in the manufacture of blended portland cements. It examines the possibilities to improve pozzolanic properties of recycled glass with new milling processes, the formation of agglomerates material during the course of grinding and their subsequent effect on the hydration process of binders. It is also the optimization of the grinding process with respect to the wear of grinding bodies, grinding energy consumption and maximize the performance of the mill.
396

Viabilidade do uso de RCD proveniente da geração dos concretos convencional e de alta resistência através da utilização do jigue como agente do beneficiamento

Cunha, Michel Gustavo Cardoso January 2017 (has links)
O presente trabalho avaliou a viabilidade do uso de Resíduos de Construção e Demolição (RCD) provenientes da geração de dois traços de concretos distintos. Um Concreto Convencional-CC (traço em massa:1:2,94:3,56; a/c:0,61) utilizando cimento CP IV 32 e outro concreto de Alta Resistência-CAR (traço em massa:1:1,11:2; a/c: 0,22; com adição, aditivo e pó xadrez vermelho) utilizando cimento CP V-ARI. Após 28 dias de cura, 3 corpos de prova de cada traço foram submetidos ao ensaio de resistência a compressão axial apresentando em média para CC 21,02 MPa e para CAR 95,09 MPa. Os materiais de ambos os traços foram cominuídos através de um britador de mandíbula ajustado para granulometria menor que 19,1 mm e retido em 4,75 mm. Com isso, foram realizados ensaios de granulometria de cada traço, e misturados em volumes iguais para o beneficiamento do material. Os primeiros ensaios foram realizados no jigue a ar, porém os resultados apresentados foram insatisfatórios. Para o jigue à água ocorreu uma separação visível de 3 estágios (Topo, Meio e Fundo) Utilizando somente as camadas de topo e fundo, os agregados reciclados de concreto (ARC) foram utilizados para confecção de novos concretos. Os resultados apontaram que a aplicação do jigue à água possibilitou um beneficiamento do material para uso como agregado graúdo. Os ensaios de resistência à compressão, os concretos produzidos com a camada de fundo do agregado reciclado superaram os produzidos com agregado natural. Nos ensaios de módulo de elasticidade, os concretos com o agregado natural exibiram resultados melhores do que os reciclados do topo, porém para os concretos produzidos com os agregados do fundo, os módulos se igualaram aos dos concretos com agregado natural. No ensaio de absorção, o concreto reciclado mostrou uma absorção maior que o concreto natural. Para a carbonatação os concretos com agregados reciclados tiveram melhores resultados. As avaliações dos efeitos foram concludentes para o uso do jigue no beneficiamento do agregado reciclado de concreto (ARC). / The present work evaluates the feasibility of using Construction and Demolition Waste (CDW) generated by two different concrete mixes, one being aconventional concrete-CC (mix:mass: 1:2, 94:3, 56, w/c: 0,61) using CP IV 32, and another being a high strength concrete - CAR (mix:mass: 1:1, 11:2, w/c: 0.22), with the addition of additive and red pigment) using cement CP V-ARI. After 28 days of curing, three test specimens of each concrete were submitted to the resistance test, presenting 21.02 MPa on average for CC and 95.09 Mpa for CAR. The materials of both mixes were comminuted by jaw crusher, and sieved to a particle size range of -19.1 mm + 4.75 mm. With this, granulometry, tests of each concrete were performed and the concretes were mixed in equal volumes for the application of the material processing. The first tests were performed by air jig, but the results were found to be unsatisfactory A visible separation of 3 stages (Top, Middle and Bottom) was achieved by use of water jig. Using only the top and bottom layers, Recycled Concrete Aggregates (RCA) was added for the creation of new concrete. The results indicate that the application of the water jig made it possible to improve the material for use as a large aggregate. For the compressive strength tests, the concretes produced with the bottom layer of the recycled aggregate surpassed those produced with natural aggregate. In the modulus of elasticity tests, concretes with the natural aggregate presented better results than those recycled from the top. For the concretes produced with the bottom aggregates, the modules matched that of the concrete with natural aggregate. In the absorption test the recycled concrete showed a higher absorption than the natural concrete. For carbonation the recycled had better results. An evaluation of the results concludes in favor of the use of water jig for the recycling of concrete aggregates (RCA).
397

Caracterização estrutural e avaliação do processo de reciclagem de diferentes formas de gesso

Cordon, Heloísa Cristina Fernandes January 2017 (has links)
Orientador: Prof. Dr. Fabio Furlan Ferreira / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2017. / A utilização do gesso na construção civil vem crescendo por diversos fatores: baixo custo do material, disponibilidade e soluções construtivas mais rápidas. Por apresentar rápido endurecimento, o desperdício de gesso é um problema sério, uma vez que resíduos de construção e demolição com altos teores de gesso não podem ser aproveitados como agregados reciclados para concretos e sua disposição em aterros pode gerar contaminação do solo e da água, além da formação de gases tóxicos e inflamáveis. Por outro lado, a reciclagem do gesso mostra-se bastante atraente, uma vez que basta calcinar o material em temperaturas amenas (140 °C a 160 °C) para que ele volte à sua composição inicial e possa ser reutilizado. Entretanto, as características do material resultante deste tipo de reciclagem devem ser muito bem avaliadas para que este processo se torne corriqueiro. Dessa forma, este trabalho tem como objetivo avaliar o impacto da reciclagem na microestrutura e nas propriedades físicas do gesso, comparando com o material comercial. Para tanto, a principal técnica de avaliação da microestrutura utilizada neste trabalho é a difração de raios X por policristais, que, aliada ao método de refinamento de Rietveld, permite quantificar as fases presentes no material, avaliando possíveis alterações causadas pela reciclagem. Ensaios de análise termogravimétrica, microscopia eletrônica de varredura, distribuição granulométrica a laser, área superficial específica por BET, densidade de massa aparente e massa específica também foram aplicados às amostras de gessos comerciais do setor da construção de São Paulo, que passaram por um processo de reciclagem composto pelas etapas de hidratação, moagem e calcinação em laboratório, bem como para a amostra de resíduo de gesso coletado em obra, também moído e calcinado em laboratório. Medidas de DRXP in-situ, para monitoramento da hidratação do gesso, serviram de base para o refinamento paramétrico em função do tempo, que permitiu avaliar a reatividade dos gessos reciclados em comparação com as amostras comerciais. Os ensaios mostraram que o teor de água utilizado na produção do resíduo não tem impacto significativo sobre a reciclagem e que algumas marcas de gesso disponíveis no mercado da construção apresentam altos teores de impurezas. O processo de reciclagem adotado não causou alterações na composição química, mas produziu um material com maior área superficial específica e menor compacidade que o material comercial de origem, o que o tornou mais reativo, comprometendo sua aplicação por alterar a consistência e reduzir o tempo útil para utilização. Sendo assim, o sucesso da reciclagem está diretamente associado ao controle da moagem, que deve ser monitorado de maneira a garantir que o material reciclado apresente área superficial específica semelhante à do material comercial. / The use of gypsum in civil construction has been increasing due to several factors: low material cost, availability and quicker constructive solutions. Because plaster wasting rapidly, plaster waste is a serious problem, since construction and demolition wastes with high gypsum contents cannot be used as recycled aggregates for concrete and their disposal in landfills can lead to soil and water contamination, besides the formation of toxic and flammable gases. On the other hand, plaster recycling proves to be quite attractive, since it is enough to calcine the material in mild temperatures (140 °C to 160 °C) so that it returns to its initial composition and thus can be reused. However, the characteristics of the material resulting from this type of recycling should be very well evaluated for this process to become commonplace. Therefore, this work aims to evaluate the impact of recycling on the microstructure and physical properties of the gypsum, comparing to the commercial material. The main technique of evaluation of the microstructure used in this work is the X-ray powder diffraction, which, together with the Rietveld refinement method, allows quantifying the phases present in the material, evaluating possible changes caused by recycling. Thermogravimetric analysis, scanning electron microscopy, laser particle size distribution, specific surface area by BET, apparent mass density and specific mass were also applied to samples of commercial plasters obtained from São Paulo construction sector. The recycling process encompasses the steps of hydration, grinding and calcination in laboratory, as well as for the sample of gypsum residue collected on site, which was also grinded and calcined in laboratory. In-situ XRD measurements for the plaster hydration monitoring contributed for the time-based parametric refinements, which allowed the evaluation of recycled plasters reactivity compared to commercial samples. The tests showed that the water content used in the waste production does not have a significant impact on the recycling and that some brands of gypsum available in the construction market have high levels of impurities. The recycling process adopted did not cause changes in the chemical composition, but produced a material with a greater specific surface area and less compactness than the original commercial material, which made it more reactive, compromising its application by altering its consistency and reducing the useful time. Therefore, the success of the recycling is directly associated to the grinding control, which must be monitored in order to ensure that the recycled material presents a specific surface area similar to that of the commercial material.
398

Caractérisation Physico-chimique et adhérence de couches d'oxydes thermiques sur des aciers recyclés. / Physico-chemical characterisation and adhesion behaviour of thermal oxide scales formed on recycled steels

Nilsonthi, Thanasak 18 September 2013 (has links)
.L’objectif de cette étude était, en premier lieu, de mettre en place en Thaïlande un testd’adhésion par traction-écaillage sur une machine de traction classique (test« macroscopique »), de le comparer au test « microscopique » Grenoblois fonctionnant dansla chambre du MEB et de l’utiliser pour évaluer l’adhérence des calamines de process sur desaciers industriels. Deux paramètres ont été étudiés, la vitesse de déformation et la teneur desaciers en silicium. Il apparaît que l’écaillage des calamines au cours du test augmente quandaugmente la vitesse de déformation. Une vitesse de déformation élevée entraîne unedéformation au premier écaillage plus faible, donc une adhérence mesurée plus faible. Ceteffet est lié aux phénomènes de relaxation. On a pu alors montrer que la présence d’oxyde(s)contenant Si, situé(s) à l’interface avec le métal, augmentait l’adhérence. Les étudesd’oxydation dans la vapeur d’eau qui ont aussi été réalisées ont révélé que la présence desilicium réduisait la vitesse d’oxydation. En augmentant la teneur en Si, les couches defayalite et de wüstite s’épaississent ; par contre, les couches externes s’amincissent. Pour lesaciers contenant du cuivre, la vitesse d’oxydation est réduite quand la teneur en Cu estaugmentée. De la même façon, les couches internes sont plus épaisses et on observe uneaugmentation du nombre de précipités de Cu quand la teneur en cet élément augmente. / The purpose of this study was first to develop in Thailand a “macroscopic” adhesion testusing a conventional tensile machine, to compare it to the micro-tensile test used in Grenobleand sitting in the SEM chamber, and to use it for measuring adhesion of scales grown duringprocessing on industrial steels. Parameters affecting the test, i.e. strain rate and Si content ofsteels were investigated. The results showed that spallation of scales during strainingincreased with increasing tensile strain rate. A higher strain rate resulted in lower straininitiating the first spallation and lower mechanical adhesion of scales, which could beexplained by a relaxation effect. Oxide containing Si existed at the steel-scale interface andpromoted adhesion of scales. Oxidation studies were also performed, and the behaviour inwater vapour of steels with different contents of Si and Cu was investigated. Increasing Sicontent tended to decrease oxidation rate. It also resulted in the thickening of the wüstite andfayalite layers which formed by internal oxidation. When Si in steel increased, theintermediate (FeO + Fe3O4) and outermost (Fe2O3 sitting on Fe3O4) layers formed by externaloxidation were thinner. For Cu containing steel, increasing Cu content tended to decrease theoxidation rate. It also decreased the innermost and intermediate layers and resulted in moreCu precipitates along steel-scale interface.
399

Processamento de compósitos de poli (tereftalato de etileno) reciclado reforçado com fibras de vidro

Mondadori, Nilcéa Mares da Luz 28 August 2007 (has links)
Neste trabalho, compósitos de PET sob a forma de flake e pós-condensado foram preparados com teores diferenciados de fibra de vidro (0, 20, 30 e 40%). Dois tipos de fibra foram utilizados: uma fibra com tratamento superficial a base de amino-silano e outra com tratamento a base de epóxi-silano. Os compósitos foram extrusados em extrusora mono-rosca, utilizando uma rosca de filete duplo com barreira, e em extrusora dupla-rosca interpenetrante co-rotacional. Após extrusão, os compósitos foram injetados a 120 ºC que, após várias temperaturas testadas, foi a temperatura que conferiu maior grau de cristalinidade do artefato final (acima de 30%). Os compósitos foram caracterizados quanto às propriedades mecânicas, térmicas e morfológicas. Os resultados mostraram que com a utilização de uma mono-rosca apropriada ao processamento de PET com fibra de vidro foi possível produzir compósitos com boas propriedades, comparáveis aos obtidos em extrusora dupla-rosca. Em relação aos tipos de PET utilizados, verificou-se que a massa molar da matriz polimérica, maior para o PET pós-condensado, teve uma pequena influência no desempenho das propriedades analisadas. Porém foi observado que os resultados foram indiferentes ao tratamento superficial das fibras testadas. Através da determinação do comprimento das fibras por análise óptica, e dos resultados experimentais do módulo de tração dos compósitos, pode-se constatar que nos compósitos injetados as fibras estão orientadas no sentido longitudinal à deformação. Com a microscopia eletrônica de varredura verificou-se que há sempre uma melhor distribuição e dispersão das fibras, com menores vazios à medida que aumenta o teor de fibras, corroborando os resultados mecânicos, sempre crescentes com o teor incorporado. A cristalinidade obtida nos corpos de prova moldados por injeção com o molde a uma temperatura de 120 ºC, aliada à presença da fibra de vidro, leva a um aumento na temperatura de distorção térmica (HDT). As análises de raios-X mostraram que com o aumento da quantidade da fibra, os picos cristalinos característicos do PET perdem definição, o que está associado à característica amorfa da fibra. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-15T17:17:43Z No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / Made available in DSpace on 2014-05-15T17:17:43Z (GMT). No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / In this work, flake and post-condensed PET composites of different glass fiber contents (0, 20, 30 and 40%) were prepared. Tow kinds of fibers were employed: one fiber having an amino silane-based surface treatment and another one having an epoxi silane-based surface treatment. The composites were extruded in a single-screw extruder with a barrier double-flight screw, and in a co-rotating interpenetrating twin-screw extruder. After extrusion the composites were injected at 120°C, this temperature being chosen after several tests indicating that it could promote the highest possible degree of crystallinity of the final product (higher than 30%). The composites were characterized as for mechanical, thermal and morphological features. Data indicate that by using a single-screw extruder proper to the processing of PET and fiber glass the properties of the obtained composites are fairly good, being comparable to those obtained from a twin-screw extruder. As for the types of PET utilized, it could be found that the molar mass of the polymeric matrix, larger for the post-condensed PET had some influence on the performance of the tested properties. On the other hand it could be observed that the surface treatment of the fibers does not influence the obtained data. Based on the optical analysis of the fiber length and the elastic modulus data it is possible to determine that the fibers of the injected composites are oriented longitudinally to the strain direction. With the aid of scanning electron microscopy (SEM), improvements in the distribution and dispersion of the fibers were always observed, with smaller voids as the fiber content increases, backing higher mechanical data as the incorporated fiber content is increased. Crystallinity resulting from injection-molded test specimens processed at 120°C, together with the presence of the glass fiber leads to a synergism in the heat distortion temperature (HDT). X-rays analyses indicate that at higher fiber content the composites show lower definition of the crystalline peaks, this being associated to the amorphous feature of the fiber.
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Tecendo Pap?is:viagem pelos saberes e pr?ticas do ensino de arte

Evangelista, Maria do Socorro de Oliveira 16 July 2005 (has links)
Made available in DSpace on 2014-12-17T14:19:53Z (GMT). No. of bitstreams: 1 MariaSOE.pdf: 2714563 bytes, checksum: 2334cc432788b4b14ffbd7c43b7d713a (MD5) Previous issue date: 2005-07-16 / Nowdays, recycling became a relevant social and educational aim among many other factors, which involve balance between man and nature. This study relates the experiences with the production of recycled handmade paper directed at the teaching in Universidade Federal do Rio Grande do Norte UFRN, and through workshops of carnauba recycled handcrafts papers as a pioneer activity accomplished at the Felix Rodrigues Foundation, in the city of Pend?ncias, A?u Valley, Rio Grande do Norte. A bibliographic review was done about the history of handmade paper and a discussion about carnauba?s paper artistic possibilities in art-education. Analyses within the context of art teaching, accordingly to Ana Mae Barbosa?s triangle propose and, also, Buoro, Ostrower and Nachmanovitch?s pedagogy of art. It deals with a group of artisans in order to establish the nature of their relationship and the possibilities of achieving more ecological awareness. Finally, we intend to realize a dialogue with Morin and other authors / Na contemporaneidade, a quest?o da reciclagem tem se destacado pela sua import?ncia social e educativa, entre tantos outros fatores que envolvem o equil?brio do homem e da natureza. Relata-se a experi?ncia de ensino de arte na Extens?o Universit?ria com a produ??o de papel reciclado artesanal, direcionado ao ensino no laborat?rio de artes pl?sticas da UFRN e em oficinas de papel artesanal com fibras de carna?ba, como atividade pioneira realizada na Funda??o F?lix Rodrigues, na cidade de Pend?ncias, munic?pio do Vale do A?u, no Rio Grande do Norte. Recomp?e-se a hist?ria do papel artesanal e um di?logo reflexivo sobre as possibilidades art?sticas do papel de carna?ba. Elabora-se ainda, uma discuss?o sobre o aproveitamento desse papel para a cria??o art?stica como elemento complementar no ensino da arte, conforme sugest?es das propostas de ensino de Ana Mae Barbosa, e outros autores da pedagogia do ensino de artes como Buoro, Ostrower, Nachmanovitch. Analisa-se a natureza das rela??es sociais estabelecidas nesses grupos numa perspectiva de renova??o da consci?ncia ecol?gica. Pretende-se trilhar os caminhos de religa??o entre saberes cient?ficos e da tradi??o, ? luz de um di?logo com Edgar Morin e outros autores

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