Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-16T20:26:43Z No. of bitstreams: 1 FlaviaSousaDeOliveira_DISSERT.pdf: 48913373 bytes, checksum: 8725e34968125209c5fa12e80d31bc55 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-18T21:45:29Z (GMT) No. of bitstreams: 1 FlaviaSousaDeOliveira_DISSERT.pdf: 48913373 bytes, checksum: 8725e34968125209c5fa12e80d31bc55 (MD5) / Made available in DSpace on 2016-08-18T21:45:29Z (GMT). No. of bitstreams: 1 FlaviaSousaDeOliveira_DISSERT.pdf: 48913373 bytes, checksum: 8725e34968125209c5fa12e80d31bc55 (MD5) Previous issue date: 2015-12-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A demanda por conforto ambiental em sistemas construtivos, no ?mbito da isola??o e conforto t?rmico, somada ao advento de novas leis que regulam os requisitos m?nimos de conforto, as exig?ncias dos consumidores pela ado??o de m?todos de produ??o mais ?limpos?, incentivaram o desenvolvimento do presente trabalho. O mesmo tem como objetivo caracterizar tecnologicamente as mat?rias-primas: res?duo termopl?stico de bot?o e res?duos de gesso para incorporar ao cimento, visando a produ??o de comp?sitos com propriedades de isola??o t?rmica: condutividade, difusividade, capacidade calor?fica e resistividade. As propriedades f?sicas, estruturais e morfol?gicas das mat?rias-primas foram investigadas atrav?s de an?lises de termogravimetria (TG), difra??o de raios X (DRX), fluoresc?ncia de raios X (FRX) e microscopia eletr?nica de varredura (MEV). Os resultados das an?lises indicaram caracter?sticas adequadas para a produ??o de comp?sito de matriz de cimento com adi??o de res?duos industriais termopl?sticos e res?duo de gesso, apresentando potencial de aplica??o destas mat?rias-primas em comp?sitos com propriedades de isola??o t?rmica. / The demand for environmental comfort in construction systems within the insulation and thermal comfort, plus the advent of new laws regulating the minimum requirements of comfort, disposal of solid industrial waste, construction waste, the requirements of consumers by adopting construction methods "cleaner", encouraged the development of this work. Aims technologically characterize the composite proposed in three types of samples (10%, 30% and 50% of thermoset plastic industrial waste) and raw materials: gypsum waste, cement and plastic thermosetting industrial waste in order to produce the composite with properties of thermal insulation: conductivity, thermal diffusivity, specific heat and resistivity. The physical, structural and morphological properties of the raw materials were investigated by thermogravimetry analysis (TG / DSC), X-ray diffraction (DRX), X-ray fluorescence (FXR) and scanning electron microscopy (MEV). Obtaining mechanical properties through the compression strength test. The analysis results indicate characteristics suitable for cement matrix composite production with the addition of thermosetting plastic industrial waste and gypsum waste, with potential application of these materials in composites with properties of thermal insulation. Finally, assessing what proportion showed up with better performance. Considering the analysis and testing carried out.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-11T20:53:57Z No. of bitstreams: 1 SistanleyJonesLimaBispo_TESE.pdf: 3279866 bytes, checksum: 4e4c98181eb5b9e3145660daab8debff (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-10-14T20:57:44Z (GMT) No. of bitstreams: 1 SistanleyJonesLimaBispo_TESE.pdf: 3279866 bytes, checksum: 4e4c98181eb5b9e3145660daab8debff (MD5) / Made available in DSpace on 2016-10-14T20:57:44Z (GMT). No. of bitstreams: 1 SistanleyJonesLimaBispo_TESE.pdf: 3279866 bytes, checksum: 4e4c98181eb5b9e3145660daab8debff (MD5) Previous issue date: 2016-06-03 / Esta pesquisa apresenta uma abordagem a cerca do processo de reciclagem do polipropileno refor?ado com fibras de curau? reprocessado. Sendo uma proposta alternativa de refor?o aos comp?sitos polim?ricos. Teores de fibras de 0%, 10%, 20% e 30% foram analisados para verifica??o de suas propriedades mec?nicas comparando-as, inclusive com as propriedades do polipropileno (PP). Os biocomp?sitos granulados foram preparados em uma extrusora. Os corpos de prova foram moldados por processo de inje??o e submetidos aos ensaios mec?nicos de tra??o uniaxial, flex?o em tr?s pontos e impacto. Para verifica??o de danos aos corpos de prova utilizou-se da an?lise por microscopia eletr?nica de varredura (MEV). Estes biocomp?sitos tamb?m foram submetidos a ensaios f?sico - qu?micos de ?ndice de fluidez (IF). Observou-se que os biocomp?sitos de polipropileno com 30% de fibras de curau? apresentaram maior m?dulo de elasticidade e menor resist?ncia ao impacto. Para todos os biocomp?sitos, os valores encontrados nos ensaios de tra??o para os limites de escoamento e tens?o de ruptura n?o sofreram altera??es ? medida que se adicionavam as fibras. Outros pontos relevantes foram o aumento da resist?ncia ? flex?o, a redu??o da degrada??o t?rmica das misturas polipropileno e fibras de curau?, e o n?o comprometimento de uma forma em geral, da fabrica??o dos biocomp?sitos, quando analisados por microscopia eletr?nica de varredura. / This research presents an approach about the polypropylene recycling process reinforced with curau? reprocessed fibers. As an alternative proposal reinforcement to polymeric composites. Levels of 10 %, 20 % and 30 % of fibers in the biocomposites were analyzed to check their mechanical properties comparing them, even with the properties of polypropylene (PP). Pellets biocomposites were prepared by the extrusion process, and the specimens were manufactured by injection process and subjected to mechanical tests of uniaxial tensile, three point bending and impact. To check for damage to the specimens was used to analysis by scanning electron microscopy (SEM). These biocomposites were also subjected to testing physical ? chemistry of index of fluidity (IF). It was observed that the polypropylene biocomposites with 30 % curau? fibers showed higher elastic modulus for both traction and to flexion and less resistance to impact. For all biocomposites, the values found in tensile tests to the limits of flow and maximum voltage have approximate values as they were added the curau? fibers. Another important point was increased resistance to bending in biocomposite as promoting the addition of curau? fibers and decrease as they were reprocessed also decreased thermal degradation of the polypropylene blends and curau? fibers, and no impairment of so in general, the production of biocomposites, when analyzed by scanning electron microscopy.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-14T18:59:50Z No. of bitstreams: 1 TatianePotiguaraOliveira_DISSERT.pdf: 4152176 bytes, checksum: 173f9461ab0652eaed0cc9d6f2283f24 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-15T20:11:56Z (GMT) No. of bitstreams: 1 TatianePotiguaraOliveira_DISSERT.pdf: 4152176 bytes, checksum: 173f9461ab0652eaed0cc9d6f2283f24 (MD5) / Made available in DSpace on 2016-01-15T20:11:56Z (GMT). No. of bitstreams: 1 TatianePotiguaraOliveira_DISSERT.pdf: 4152176 bytes, checksum: 173f9461ab0652eaed0cc9d6f2283f24 (MD5) Previous issue date: 2014-08-01 / O comp?sito Al2O3-Cu alia a fase cer?mica da alumina, que ? extremamente dura e resistente, por?m muito fr?gil, ? fase met?lica do cobre de alta ductilidade e elevada tenacidade ? fratura. Tais caracter?sticas fazem desse material um forte candidato para aplica??o como ferramenta de corte. P?s comp?sitos Al2O3-Cu nanocristalinos e de alta homogeneidade podem ser produzidos por moagem de alta energia, assim como estruturas densas e de melhores propriedades mec?nicas podem ser obtidas por sinteriza??o com fase l?quida. Este trabalho investiga o efeito da moagem de alta energia na dispers?o das fases Al2O3 e Cu, bem como a influ?ncia do teor de Cu na forma??o das part?culas comp?sitas Al2O3-Cu. Um moinho planet?rio Pulverisatte 7 de alta energia foi usado para efetuar os experimentos de moagem. P?s de Al2O3 e Cu na propor??o de 5, 10 e 15% em massa de Cu foram colocados para moer em um recipiente com bolas de metal duro e ?lcool et?lico. Uma raz?o em massa de p? para bolas de 1:5 foi utilizada. Todos os p?s foram mo?dos at? 100 horas, e amostras de p?s foram coletadas ap?s 2, 10, 20, 50 e 70 horas de moagem. Compactos de p?s comp?sitos com forma cil?ndrica de 8 mm de di?metro foram prensados em matriz uniaxial e sinterizados em forno resistivo a 1200, 1300 e 1350 oC por 60 minutos e sob uma atmosfera de arg?nio e hidrog?nio. A taxa de aquecimento usada foi de 10 oC/min. Os p?s e as estruturas dos corpos sinterizados foram caracterizados por DRX, MEV e EDS. An?lises de TG, DSC e granulometria tamb?m foram usadas para caracterizar os p?s mo?dos, assim como, a dilatometria foi empregada para observar a contra??o dos corpos sinterizados. A densidade dos corpos verdes e sinterizados foi medida usando o m?todo geom?trico (massa/volume). Medidas de microdureza vickers com carga de 500 g durante 10 s foram efetuadas nas estruturas sinterizados. Os comp?sitos Al2O3?Cu com 5% de cobre alcan?aram densidade de 61% da densidade te?rica, e uma dureza de 129 HV quando sinterizados a 1300 oC por 1h. Diferentemente, menores densidades (59 e 51% da densidade te?rica) e durezas (110 e 105 HV) foram alcan?adas quando o teor de cobre aumento para 10 e 15%. / The Cu-Al2O3 composite ceramic combines the phase of alumina, which is extremely hard and durable, yet very brittle, to metallic copper phase high ductility and high fracture toughness. These characteristics make this material a strong candidate for use as a cutting tool. Al2O3-Cu composite powders nanocrystalline and high homogeneity can be produced by high energy milling, as well as dense and better mechanical structures can be obtained by liquid phase sintering. This work investigates the effect of high-energy milling the dispersion phase Al2O3, Cu, and the influence of the content of Cu in the formation of Cu-Al2O3 composite particles. A planetary mill Pulverisatte 7 high energy was used to perform the experiments grinding. Al2O3 powder and Cu in the proportion of 5, 10 and 15% by weight of Cu were placed in a container for grinding with balls of hard metal and ethyl alcohol. A mass ratio of balls to powder of 1:5 was used. All powders were milled to 100 hours, and powder samples were collected after 2, 10, 20, 50 and 70 hours of grinding. Composite powders with compact cylindrical shape of 8 mm diameter were pressed and sintered in uniaxial matrix resistive furnace to 1200, 1300 to 1350 ?C for 60 minutes under an atmosphere of argon and hydrogen. The heating rate used was 10?C/min. The powders and structures of the sintered bodies were characterized by XRD, SEM and EDS. Analysis TG, DSC and particle size were also used to characterize the milled powders, as well as dilatometry was used to observe the contraction of the sintered bodies. The density of the green and sintered bodies was measured using the geometric method (mass / volume). Vickers microhardness with a load of 500 g for 10 s were performed on sintered structures. The Cu-Al2O3 composite with 5% copper density reached 61% of theoretical density and a hardness of 129 HV when sintered at 1300 ? C for 1h. In contrast, lower densities (59 and 51% of the theoretical density) and hardness (110 HV and 105) were achieved when the copper content increases to 10 and 15%.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-20T21:46:40Z No. of bitstreams: 1 RafaelaLuizPereiraSantos_TESE.pdf: 5717758 bytes, checksum: 765e67dde7c80007f582df680380b1c9 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-21T19:39:57Z (GMT) No. of bitstreams: 1 RafaelaLuizPereiraSantos_TESE.pdf: 5717758 bytes, checksum: 765e67dde7c80007f582df680380b1c9 (MD5) / Made available in DSpace on 2016-07-21T19:39:57Z (GMT). No. of bitstreams: 1 RafaelaLuizPereiraSantos_TESE.pdf: 5717758 bytes, checksum: 765e67dde7c80007f582df680380b1c9 (MD5) Previous issue date: 2016-01-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / All-ceramic restorations have been widely used as aesthetic standard in nowadays dentistry, to replace the tooth structure (appearance and function). However, failures associated with chipping and delamination of the veneering porcelain from zirconia substructure still high when compared to metal-ceramic systems. This study aimed address these problems by improving the mechanical strength of veneering porcelain and by improving its adhesion to zirconia substrate. First, the addition of a stronger ceramic second phase (zirconia particles) to feldspathic porcelain was studied. This study began with the preliminary characterization of zirconia synthesized by Complex Polymerization Method (CPM) and commercial zirconia. It was found that the synthesized zirconia did not show improved properties when compared to commercial zirconia. Commercial zirconia powders were thus used thereafter. The influence of the type of powder (pre-sintered or agglomerated) in the mechanical properties and wear of porcelain composites (20vol.%) was evaluated. The pre-sintered powders increased the mechanical strength and wear of the composites compared to agglomerated powders. Then, it was determined the amount of second phase (0-50vol.%) that maximizes the mechanical properties of the porcelain-zirconia composites. It was concluded that the composites with 30vol.% of zirconia showed the best results for wear and flexural strength (198.5MPa). Finally, it was evaluated the influence of the type of surface treatment (sandblasting or holes) and the deposition of a composite interlayer (porcelain reinforced with 30vol.% of zirconia), on the zirconia surface, on the bond strength between the veneering porcelain and the zirconia substructure. The highest bond strength values were found for specimens having simultaneously holes on the surface of zirconia and the composite interlayer between the zirconia substructure and the veneering porcelain (138 ? 19MPa). It was demonstrated that the correct configuration of the interface between the zirconia substructure and the veneering porcelain can lead to all-ceramic restorations with enhanced mechanical strength and improved clinical performance. / Materiais comp?sitos restauradores representam um dos mais bem sucedidos biomateriais na pesquisa moderna, na substitui??o do tecido biol?gico em apar?ncia e fun??o. Nesta linha, a porcelana feldsp?tica tem sido largamente usada em odontologia devido suas interessantes qualidades como estabilidade de cor, propriedades est?ticas, elevada durabilidade mec?nica, biocompatibilidade, baixa condutividade t?rmica e elevada resist?ncia ao desgaste. Entretanto, este material ? fr?gil e pode falhar em ambiente oral devido ao micro-vazamento, baixa resist?ncia ? tra??o, descolagem ou fratura. Assim, para melhorar as propriedades mec?nicas da porcelana, a zirc?nia parcialmente estabilizada com ?tria (Y-TZP) pode ser uma boa alternativa para fortalecer e produzir infraestruturas totalmente cer?micas (coroas e pr?teses parciais fixas). Portanto, este estudo tem por objetivo avaliar as propriedades mec?nicas e caracter?sticas microestruturais da porcelana refor?ada com zirc?nia (3Y-TZP) em diferentes conte?dos e as vari?veis que afetam as propriedades mec?nicas destes materiais. O estudo de caracteriza??o revelou que a zirc?nia comercial apresenta melhores resultados quando comparada com a zirc?nia sintetizada pelo CPM. Assim, os estudos seguintes utilizaram a zirc?nia comercial para todos os testes requeridos. As part?culas de zirc?nia apresentam elevadas propriedades mec?nicas quando comparadas a zirc?nia aglomerada. Os diferentes conte?dos revelam que as propriedades mec?nicas dos comp?sitos aumentam com o aumento do conte?do volum?trico at? 30% vol.% (198,5Mpa), ou seja, maior resist?ncia ? flex?o quando comparada com os outros comp?sitos. Do mesmo modo, a resist?ncia ao desgaste para os comp?sitos com (30%, vol.% de zirc?nia) apresenta valores superiores quando comparado aos demais comp?sitos. Na ades?o cer?mico-cer?mico a porcelana exibe elevada ades?o para a superf?cie de zirc?nia porosa quando comparada a superf?cie rugosa. Os furos superficiais (PZ) e aplica??o de comp?sitos com camada intermedi?ria (RZI) na zirc?nia causam separadamente uma melhoria da resist?ncia ao cisalhamento da zirc?nia-porcelana quando comparados as amostras convencionais de zirc?nia-porcelana (RZ), embora n?o sejam estatisticamente significativas (p>0.05). A presen?a de uma camada intermediaria produz um aumento significativo na for?a de liga??o (~55%) em rela??o as amostras convencionais (RZ). Portanto, a correta a correta configura??o e tratamento superficial podem produzir subestruturas com qualidade e for?a de liga??o adequadas aos requisitos odontol?gicos.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-22T14:59:52Z No. of bitstreams: 1 HeytorVitorSouzaBezerraDeAzevedo_DISSERT.pdf: 4226943 bytes, checksum: 879f905d96e12f6e15faa6de0fec4be5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-26T22:08:45Z (GMT) No. of bitstreams: 1 HeytorVitorSouzaBezerraDeAzevedo_DISSERT.pdf: 4226943 bytes, checksum: 879f905d96e12f6e15faa6de0fec4be5 (MD5) / Made available in DSpace on 2016-07-26T22:08:45Z (GMT). No. of bitstreams: 1 HeytorVitorSouzaBezerraDeAzevedo_DISSERT.pdf: 4226943 bytes, checksum: 879f905d96e12f6e15faa6de0fec4be5 (MD5) Previous issue date: 2016-01-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Comp?sitos ? base de alumina (Al2O3), carbeto de tungst?nio (WC) e cobalto (Co) apresentam propriedades espec?ficas como baixa densidade, alta resist?ncia ? oxida??o, alto ponto de fus?o e elevada in?rcia qu?mica. Esse comp?sito revela ser um material promissor para ser aplicado em diversos campos da engenharia. Este trabalho tem como objetivo avaliar algumas propriedades mec?nicas durante a confec??o e, ap?s a sinteriza??o do comp?sito (Al2O3 - WC - Co). P?s comp?sitos com a composi??o de 80%.p de Al2O3, 18%.p de WC e 2%.p de Co foram processados pela rota de moagem de alta energia (MAE), em moinho planet?rio por 50 horas, bem como por mistura manual em um recipiente de vidro, seguindo a mesma propor??o em peso. Amostras foram coletadas (2, 10, 20, 30, 40 e 50 horas) durante o processo de moagem. Em seguida, os p?s foram prensados no formato de amostra circular com di?metro de 5 mm em uma prensa uniaxial com press?es de 200 e 400 MPa. A sinteriza??o ocorreu de duas maneiras: a primeira sinteriza??o via fase s?lida foi realizada ? 1300 ?C e ? 1126 ?C durante 1h com taxa de aquecimento de 10?C/min em forno resistivo sob atmosfera de arg?nio as press?es de compacta??o utilizadas foram de 200 e 400 MPa, a segunda sinteriza??o foi realizada em dilat?metro via fase s?lida ? 1300 ?C com press?o de compacta??o de 200 MPa, tamb?m foi realizada em dilat?metro outra sinteriza??o, desta vez por fase l?quida ? 1550 ?C com press?es de compacta??o de 200 e 400 MPa, obedecendo os mesmos par?metros utilizados no forno resistivo. As mat?rias-primas foram caracterizadas por difra??o de raios X - (DRX), fluoresc?ncia de raios X - (FRX), microscopia eletr?nica de varredura (MEV), espectroscopia por dispers?o de energia (EDS) e particulometria a laser. As amostras sinterizadas foram submetidas a ensaios de microdureza. Os resultados mostraram que a moagem de alta energia atingiu os objetivos quanto ao tamanho de part?cula e a densifica??o do comp?sito. Entretanto, a microdureza n?o alcan?ou resultados significativos, isso ? um ind?cio que o comp?sito possui baixa tenacidade ? fratura. / Composites based on alumina (Al2O3), tungsten carbide (WC) and cobalt (Co) exhibit specific properties such as low density, high oxidation resistance, high melting point and high chemical inertia. That composite shows to be a promising material for application in various fields of engineering. In this work, the mechanical properties of the composite (Al2O3 ? WC ? Co), particularly density and hardness, were evaluated according to the effects of the variables of powder processing parameters, green compact and sintered. Powder composites with the composition of 80 wt% Al2O3, 18 wt% WC and 2 wt% Co were processed by high energy ball milling in a planetary mill for 50 hours as well as mixed by manual mixing in a glass vessel with the same proportion. Samples were collected (2, 10, 20, 30, 40 and 50 hours) during the milling process. Then, the powders were compacted in a cylindrical die with 5 mm in diameter in a uniaxial press with pressures of 200 and 400 MPa. The sintering was in two stages: first, the solid phase sintering was performed at 1126 and 1300 ?C for 1 hour with a heating rate of 10 ?C/min in a resistive furnace under argon atmosphere for green samples compacted in 200 and 400 MPa; the second sintering was performed on dilatometer in solid phase at 1300 ?C for green sample compacted in 200 MPa, another sintering also was performed on dilatometer, this time in liquid phase at 1550 ?C for green samples compacted in 200 and 400 MPa, with the same parameters used in resistive furnace. The raw materials were characterized by X ? ray diffraction (XRD), X ? ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and laser particlemeter. The sintered samples were subjected to microhardness testing. The results showed that high energy milling achieved to the objectives regarding the particle size and the dispersion of composite phases. However, the hardness did not achieve to significant results, this is an indication that the composite has low fracture toughness.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-09T22:54:12Z No. of bitstreams: 1 JoseAntonioMartinsNeto_TESE.pdf: 2915653 bytes, checksum: 3e8f8a24fb45e2bdcd86834ce7b0d770 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-12T22:54:51Z (GMT) No. of bitstreams: 1 JoseAntonioMartinsNeto_TESE.pdf: 2915653 bytes, checksum: 3e8f8a24fb45e2bdcd86834ce7b0d770 (MD5) / Made available in DSpace on 2016-08-12T22:54:51Z (GMT). No. of bitstreams: 1 JoseAntonioMartinsNeto_TESE.pdf: 2915653 bytes, checksum: 3e8f8a24fb45e2bdcd86834ce7b0d770 (MD5) Previous issue date: 2016-03-04 / A constante e atual busca de alternativas sustent?veis tem levado a demanda de esfor?os dos pesquisadores na investiga??o e obten??o de novos materiais, motivando a escalada do desenvolvimento produtivo ecologicamente correto e apresentando solu??es simples e pr?tica com rentabilidade econ?mica vi?vel. Neste sentido, a utiliza??o de materiais procedentes de fontes renov?veis naturais, vegetais, apresenta grande potencial de aplicabilidade e s?o vistos como material alternativo para um desenvolvimento sustent?vel. A sustentabilidade questionada, dentre outros quesitos, depende da renov?vel multiplica??o da mat?ria-prima. Como material alternativo as fibras vegetais podem ser aplicadas para produ??o de uma gama de materiais comp?sitos amenizando o uso de materiais oriundos de fontes n?o renov?veis Nesta tese foram utilizadas mantas de sisal para obten??o de um comp?sito tendo como matriz uma resina poli?ster ortoft?lica. As mantas foram submetidas a tratamento superficial, em ?gua fervente, por 15 minutos. As mantas de fibras de sisal utilizadas tinham, respectivamente, 5%, 10% e 15% da massa do comp?sito. O comp?sito foi obtido e caracterizado mec?nica e termicamente para as formula??es escolhidas. Foram fabricadas v?rias placas do comp?sito para obten??o dos corpos de provas para os ensaios de caracteriza??o obedecendo ?s normas pertinentes. Os comp?sitos obtidos apresentaram resist?ncia mec?nica de tra??o e flex?o inferiores ? da matriz, sendo vi?vel sua utiliza??o onde s?o requeridas baixas solicita??es de carga. O resultado mais expressivo do comp?sito estudado deu-se para a absor??o de energia de impacto, muito superior a da matriz utilizada. Outras propriedades de destaque foram a absor??o em ?leo e a densidade. Provou-se a viabilidade de obten??o do comp?sito para as tr?s formula??es estudadas C5, C10 e C15, cuja mais vi?vel foi a C10. Para demonstrar a viabilidade de utiliza??o do comp?sito foram fabricados um rel?gio de parede, um banco, uma cadeira e uma prateleira, estruturas de baixas solicita??es mec?nicas. Concluiu-se que as mantas de sisal exerceram a fun??o de carga no comp?sito. / The constant search for sustainable alternatives has earned great effort of researchers in research and obtaining new materials, encouraging the rise of eco-friendly productive development and providing simple and practical solutions to economic profitability. In this sense, the use of materials derived from natural renewable sources, vegetables, has great potential applicability to sustainable development. As alternative materials plant fibers can be applied to production of a range of composite materials easing the use of materials derived from non-renewable this thesis were sisal mats used for achieving a composite matrix having as one orthophthalic polyester resin. The webs were subjected to surface treatment in boiling water for 15 minutes. The webs of sisal fibers used were, respectively, 5%, 10% and 15% of the composite weight. The composite was obtained and characterized mechanically and thermally to the chosen formulations. several plates of the composite to obtain the body of evidence for the characterization tests complying with the relevant rules were made. The obtained composites showed strength tensile and bending lower than the array, so it can be used where are required low load requests. The most significant result of the composite studied given to the impact energy absorption, far superior to the matrix used. Other properties were highlighted in oil absorption, and density. It proved the feasibility of obtaining the composite for the three formulations studied C5, C10 and C15 being the most feasible to C10. To demonstrate the feasibility of using composite were made a wall clock, a bench, a chair and a shelf, low mechanical stress structures. It was concluded that the sisal rugs exercised the load function in the composite.

Made available in DSpace on 2014-12-17T14:57:45Z (GMT). No. of bitstreams: 1 Andre Luiz dos Santos Silva.pdf: 2919586 bytes, checksum: 16be0b485378f56625d3954714b825d8 (MD5) Previous issue date: 2006-05-26 / Structures capable of absorbing large amounts of energy are of great interest, particularly for the automotive and aviation industries, to reduce tbe impact on passengers in the case of a collision. The energy absorption properties of composite materials structures can be tailored, thus making these structures an appealing option a substitute of more traditional structures in applications where energy absorption is crucial. ln this research, the influence of some parameters, which affect the energy absorption capacity of composite material tubes, was investigated. The tubes were fabricated by hand lay-up, using orthophthalic polyester resin and a plain weave E-glass fabric Test specimens were prepared and tested under compression load. The ?nfluence of the following parameters on the specific energy absorption capacity of the tubes was studied: fiber configuration (0/90? or ? 45?), tube cross-section (circular or square), and processing conditions (with or without vacuum). The results indicated that circular cross-section tubes with fibers oriented at 0/90? presented the highest level of specific energy absorbed. Further, specimens from tubes fabricated under vacuum displayed higher energy absorption capacity, when compared with specimens from tubes fabricated without vacuum. Thus, it can be concluded that the fabrication process with vacuum produce composite structures with better energy absorption capacity / Estruturas com alta capacidade de absor??o de energia s?o de grande interesse, tanto na ?rea automotiva quanto na aeron?utica, na busca de reduzir ao m?ximo a energia de impacto sobre os passageiros em caso de colis?o. As propriedades de estruturas de materiais comp?sitos podem ser projetadas para absorver energia, fazendo dessas estruturas uma op??o atraente para a substitui??o daquelas de materiais mais tradicionais, em aplica??es onde a capacidade de absor??o de energia ? fundamental. Neste estudo foi realizada uma an?lise da influ?ncia de alguns fatores que afetam a capacidade de absor??o de energia de tubos de materiais comp?sitos. Os tubos foram fabricados pelo processo de lamina??o manual com matriz de resina poli?ster insaturada ortoft?lica, tendo, como refor?o, tecido bidirecional de fibra de vidro E. Corpos-deprova foram produzidos dos tubos e submetidos a carregamento de compress?o. Foram investigadas as influ?ncias dos seguintes par?metros na capacidade de absor??o de energia espec?fica dos tubos: disposi??o de fibra (0/90? ou +/- 45?), forma da se??o transversal (circular ou quadrada), e processo de fabrica??o (com ou sem a aplica??o de v?cuo). Os resultados mostraram que os tubos de se??o transversal circular, com disposi??o de fibra a 0/90?, apresentaram os maiores valores de absor??o de energia espec?fica. Al?m disso, os corpos-de-prova de tubos submetidos ? aplica??o de v?cuo no processo de fabrica??o, apresentaram maiores valores de capacidade energia espec?fica, quando comparados com os corpos-de- prova de tubos fabricados sem aplica??o de v?cuo. Assim, pode-se concluir que o processo de fabrica??o com aplica??o de v?cuo proporciona aos comp?sitos confeccionados, melhores propriedades com rela??o ? absor??o de energia

Made available in DSpace on 2014-12-17T14:57:49Z (GMT). No. of bitstreams: 1 ReginaldoDS.pdf: 1111406 bytes, checksum: d55968c3491b3eb05981971626b26f4e (MD5) Previous issue date: 2008-07-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / A housing unit was built to study the thermal performance, and of material using a composite made of gypsum and EPS ground. We used two techniques of construction, using blocks, and filling on the spot. Two compositions of the composite were studied. The blocks were fixed using conventional mortar. In the technical of filling on the spot were used PET bottles up inside the walls to provide mechanical and thermal resistance. Compression tests were realized according to the ABNT standard of sealing bricks. It is going to be shown an analysis of the thermal comfort through the use of thermocouples placed on the walls of the building, internally and externally. The manufacturing viability of houses, using recyclable materials, through the use of composite materials proposed will be demonstrated. The constructive aspects showing the advantages and disadvantages of the technique used also will be broached. The block used presents structural functions and thermal insulating, is low cost and represents an alternative to the use of EPS and PET bottles which are materials that end up occupying much space in the landfills, giving than an ecologically correct use. The results of thermal analysis shows the thermal comfort provided by the composite by the obtainment of a difference between the internal and external surfaces of the walls more exposed to the sun around 7? C. The average temperature of the air inside the building, around 28.0 ? C was below the zone of thermal comfort recommended for countries with hot weather / Foi constru?da uma unidade habitacional para estudo de desempenho t?rmico, e de materiais utilizando um comp?sito ? base de gesso e EPS triturado. Foram utilizadas duas t?cnicas de constru??o, usando blocos, e enchimento in loco. Duas composi??es do comp?sito foram estudadas. Os blocos foram assentados utilizando argamassa convencional. Na t?cnica do enchimento in loco utilizou-se garrafas PET no interior das paredes para proporcionar resist?ncias t?rmica e mec?nica. Foram realizados ensaios de compress?o m?nima segundo as normas da ABNT para blocos de veda??o. Foi realizada uma an?lise de conforto t?rmico, atrav?s do uso de termopares colocados nas paredes da edifica??o, interna e externamente. Demonstrar-se-? as viabilidades de fabrica??o de casas, utilizando materiais recicl?veis, atrav?s do uso do material comp?sito proposto. Abordar-se-? tamb?m os aspectos construtivos mostrando as vantagens e desvantagens da t?cnica utilizada. O bloco utilizado apresenta fun??es estruturais e de isolante t?rmico, tem baixo custo e representa uma alternativa para o aproveitamento do EPS e garrafas PET que s?o materiais que acabam ocupando muito espa?o nos aterros sanit?rios, dando-lhe um fim ecologicamente correto. Os resultados da an?lise t?rmica demonstram o conforto t?rmico proporcionado pelo comp?sito pela obten??o de uma diferen?a de temperatura entre as superf?cies interna e externa das paredes mais expostas ao sol em torno de 7? C. A temperatura m?dia do ar no interior da edifica??o, em torno de 28,0? C ficou dentro da zona de conforto t?rmico recomendada para pa?ses de clima quente

Made available in DSpace on 2014-12-17T14:57:51Z (GMT). No. of bitstreams: 1 MarcoASR_TESE.pdf: 5586767 bytes, checksum: d92d904a4f89177a814a13f5f7230b94 (MD5) Previous issue date: 2011-07-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this study were conducted experimental procedures for determination of variation of the expandability of rigid polyurethane foam (PUR) from a natural oil polyol (NOP), specifically the Castor oil plant, Ricinus communis, pure and additions of the vermiculite in phase dispersed in different percentage within a range from 0% to 20%, mass replacement. From the information acquired, were defined the parameters for production of bodies of test, plates obtained through controlled expansion, with the final volume fixed. Initially, the plates were subjected to thermal performance tests and evaluated the temperature profiles, to later be extracted samples duly prepared in accordance with the conditions required for each test. Was proceeded then the measurement of the coefficient of thermal conductivity, volumetric capacity heat and thermal diffusivity. The findings values were compared with the results obtained in the tests of thermal performance, contributing to validation of the same. Ultimately, it was investigated the influence that changes in physical-chemical structure of the material had exerted on the variation of thermophysical quantities through gas pycnometry, scanning electron microscopy (SEM) combined with energy dispersive X-ray fluorescence spectroscopy (EDXRF), infrared spectroscopy using Fourier transform (FTIR), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Based on the results obtained was possible to demonstrate that all load percentage analyzed promoted an increase in the potential expansion (PE) of the resin. In production of the plates, the composites with density near at the free expansion presented high contraction during the cure, being the of higher density adopted as definitive standard. In the thermal performance tests, the heating and cooling curves of the different composites had presented symmetry and values very close for lines of the temperature. The results obtained for the thermophysical properties of composites, showed little difference in respect of pure foam. The percentage of open pores and irregularities in the morphology of the composites were proportionate to the increment of vermiculite. In the interaction between the matrix and dispersed phase, there were no chemical transformations in the region of interface and new compounds were not generated. The composites of PUR-NOP and vermiculite presented thermal insulating properties near the foam pure and percentage significantly less plastic in its composition, to the formulation with 10% of load / Neste estudo, foram realizados procedimentos experimentais para determina??o da varia??o da expansibilidade da espuma r?gida de poliuretano (PUR) de um poliol de ?leo natural (NOP), especificamente o de mamona, Ricinus communis, puro e acrescido de vermiculita na fase dispersa, em distintos percentuais, dentro de uma faixa de 0% a 20%, de substitui??o em massa. A partir das informa??es adquiridas, foram definidos os par?metros para produ??o dos corpos de prova, placas obtidas atrav?s de expans?o controlada, com volume final fixo. Inicialmente, as placas foram submetidas a testes de desempenho t?rmico, sendo avaliados os perfis de temperatura, para posteriormente serem extra?das amostras, devidamente preparadas conforme as condi??es exigidas para cada ensaio. Procedeu-se ent?o a medi??o do coeficiente de condutividade t?rmica, capacidade t?rmica volum?trica e difusividade t?rmica. Os valores encontrados foram comparados com os resultados obtidos nos testes de desempenho t?rmico, contribuindo para valida??o dos mesmos. Por fim, foi investigada a influ?ncia que as altera??es na estrutura f?sico-qu?mica do material, exerceram sobre a varia??o das grandezas termof?sicas, por meio de picnometria a g?s, microscopia eletr?nica de varredura (MEV) combinada com espectroscopia de fluoresc?ncia de raios-X por energia dispersiva (EDXRF), espectroscopia de infravermelho com transformada de Fourier (FTIR), an?lise termogravim?trica (TGA) e an?lise t?rmica diferencial (DTA). Com base nos resultados obtidos foi poss?vel demonstrar que todos os percentuais de carga analisados promoveram um aumento do potencial de expans?o (PE) da resina. Na produ??o das placas, os comp?sitos com densidade pr?xima ? expans?o livre apresentaram grande contra??o na cura, sendo adotados os de maior densidade como padr?o definitivo. Nos ensaios de desempenho t?rmico, as curvas de aquecimento e resfriamento dos diferentes comp?sitos apresentaram simetria e valores muito pr?ximos para as linhas de temperatura. Os resultados obtidos para as propriedades termof?sicas dos comp?sitos, demonstraram pouca diferen?a em rela??o aos da espuma pura. O percentual de poros abertos e irregularidades na morfologia dos comp?sitos foram proporcionais ao incremento da vermiculita. Na intera??o entre matriz e fase dispersa n?o ocorreram transforma??es qu?micas na regi?o de interface e n?o foram gerados novos compostos. Os comp?sitos de PUR-NOP e vermiculita apresentaram propriedades isolantes t?rmicas pr?ximas as da espuma pura e percentual significativamente menor de pl?stico em sua composi??o, para a formula??o com 10% de carga

Made available in DSpace on 2014-12-17T14:57:51Z (GMT). No. of bitstreams: 1 JairJF_TESE.pdf: 2222193 bytes, checksum: b572697498429b717de3a15791bc4a09 (MD5) Previous issue date: 2011-07-21 / Thermal recovery methods, especially steam injection, have been used to produce heavy oils. However, these methods imply that the metallic casing-cement sheath interface is submitted to thermal cycling. As a consequence, cracking may develop due to the thermal expansion mismatch of such materials, which allows the flow of oil and gas through the cement sheath, with environmental and economical consequences. It is therefore important to anticipate interfacial discontinuities that may arise upon Thermal recovery. The present study reports a simple alternative method to measure the shear strength of casing-sheath interfaces using pushthrough geometry, applied to polymer-containing hardened cement slurries. Polyurethane and recycled tire rubber were added to Portland-bases slurries to improve the fracture energy of intrinsically brittle cement. Samples consisting of metallic casing sections surrounded by hardened polymer-cement composites were prepared and mechanically tested. The effect of thermal cycles was investigated to simulate temperature conditions encountered in steam injection recovery. The results showed that the addition of polyurethane significantly improved the shear strength of the casing-sheath interface. The strength values obtained adding 10% BWOC of polyurethane to a Portland-base slurry more than doubled with respect to that of polyurethane-free slurries. Therefore, the use of polyurethane significantly contributes to reduce the damage caused by thermal cycling to cement sheath, improving the safety conditions of oil wells and the recovery of heavy oils / Atualmente, os m?todos com maior ?ndice de sucesso de recupera??o de ?leos pesados s?o os t?rmicos, principalmente a inje??o de vapor. Este m?todo de recupera??o coloca a interface entre o revestimento met?lico e a bainha de cimento em ciclagem t?rmica, que devido ? diferen?a de coeficientes de expans?o entre os dois materiais pode provocar o surgimento de trincas, possibilitando a passagem de fluidos pela bainha de cimento. Isto ocasiona s?rios riscos s?cio-econ?micos e ambientais. Para minimizar este problema, foi realizado um estudo que consiste em mensurar a resist?ncia ao cisalhamento entre um tubo de a?o e uma bainha de cimento. Ao material cimentante foram adicionados pol?meros, como poliuretana e borracha reciclada triturada de pneus. A adi??o de pol?meros visa melhorar a plasticidade do material cimentante e, assim, aumentar a ader?ncia da pasta endurecida sobre o revestimento, bem como a energia de ruptura do conjunto. Diante disso, a meta principal desse estudo foi avaliar a ader?ncia de comp?sitos cimentantes para po?os de petr?leo com revestimentos met?licos ap?s ciclagens t?rmicas, simulando as condi??es de varia??o de temperatura a que po?os de petr?leo s?o submetidos durante a recupera??o de ?leos pesados por m?todos t?rmicos. Observou-se que com a adi??o de poliuretana houve uma melhoria significativa da ader?ncia da interface revestimento met?lica - bainha de cimento com rela??o ? pasta padr?o, sem pol?meros. Os melhores resultados obtidos foram com pastas contendo 10% de poliuretana, que apresentaram aumento de mais de 100% na resist?ncia ao cisalhamento, em rela??o ? pasta padr?o. A adi??o de poliuretana ? pasta de cimento contribui de forma significativa para reduzir o dano causado pela ciclagem t?rmica a bainhas de cimento, melhorando a seguran?a e as condi??es de produ??o de po?os de petr?leo sujeitos ? recupera??o secund?ria por m?todos t?rmicos