Made available in DSpace on 2015-03-03T15:36:12Z (GMT). No. of bitstreams: 1 EduardoSS_DISSERT.pdf: 804086 bytes, checksum: 7991c16751047e96e7a210e52bd8df36 (MD5) Previous issue date: 2013-08-14 / The aim of this work is to provide a text to support interested in the main systems of amortization of the current market: Constant Amortization System (SAC) and French System, also known as Table Price. We will use spreadsheets to facilitate calculations involving handling exponential and decimal. Based on [12], we show that the parcels of the SAC become smaller than the French system after a certain period. Further then that, we did a comparison to show that the total amount paid by SAC is less than the French System / O objetivo deste trabalho e oferecer um texto de apoio aos interessados nos principais sistemas de amortizac??o do mercado atual: Sistema de Amortiza??o Constante (SAC) e Sistema Franc?s, tamb?m conhecido por Tabela Price. Utilizamos planilhas eletr?nicas para facilitar os c?lculos que envolvem manipula??o de exponenciais e decimais. Baseados em [12], mostramos que as presta??es do SAC tornam-se menores que as do Sistema Franc?s a partir de certo per?odo de financiamento. Al?m disso, fazemos uma compara??o para mostrar que o montante total pago pelo SAC e menor que o do Sistema Franc?s

Made available in DSpace on 2015-03-13T17:08:14Z (GMT). No. of bitstreams: 1 LeandsonRFL_Ate_ cap6.pdf: 2182746 bytes, checksum: 25783c90c53780b39921fc195504a37c (MD5) Previous issue date: 1998-10-27 / This MSc dissertation presents the results of a research carried out in a 500 km2 area in the N?sia Floresta county. The main goal of the research was to evaluate fault influence on hidrology features of aquifers and lakes, mainly in the Barreiras Group and in the Bonfim lake cluster respectively. The Precambrian crystalline basement is made of Caic? Complex rocks. They are capped by cretaceous sedimentary rocks and by cenozoic sedimentary rocks. Only the latter outcrop in the study area, wheareas the former are described in boreholes. Faults cut across all stratigraphic units and their main trends are NW, NE and E-W, which have been generated by E-W compression. Subordinate N-S trending faults also take place and have been generated by N-S oriented compression. Fault controlled hydrologic features are observed throughout the study area. There are sudden changes in saturated thicknesses of the Barreiras Aquifer due to vertical displacement of the Barreiras Group. The most important underground water source of the Bonfim Lake is related to abrupt thickness changes of the aquifer. In addition, the main faults control the underground drainage network and, probably, change in direction of equipotential surfaces seen on the potenciometric map. Regarding the surface hydrologic features, faults also control river and stream channels, as well as lake origin and shapes. The Bonfim Lake, in particular, has its peculiar shape, which follows NW and NE lineaments, and origin related to faulting and probably underground carstics processes / Esta disserta??o apresenta os resultados de uma pesquisa desenvolvida numa ?rea com cerca de 500 km2, a maior parte situada no munic?pio de N?sia Floresta-RN. O objetivo central ? avaliar as influ?ncias da estrutura??o regional na hidrologia dos terrenos sedimentares cenoz?icos, com destaque especial para o Aq??fero Barreiras e o sistema lacustre do Bonfim. Foi adotado uma metodologia fundamentada no emprego de t?cnicas geof?sicas (gravimetria e eletro-resistividade) e estruturais. A estratigrafia da ?rea ? constitu?da pelo embasamento cristalino Pr?-Cambriano, correlato ao Complexo Caic?, sotoposto a sedimentos cret?cicos e capeados por unidades estratigr?ficas cenoz?icas, na qual apenas estas ?ltimas s?o aflorantes. O arcabou?o tectono-estrutural ? formado por uma complexa estrutura??o regional, caracterizada em tr?s dire??es principais: NW, NE e E-W, aproximadamente, al?m de uma quarta dire??o, menos expressiva, com orienta??o geral N-S. Esta estrutura??o representa o resultado da atua??o de um campo de tens?es com compress?o e distens?o m?ximas em E-W e N-S, respectivamente, ? exce??o do trend N-S que est? associado a uma compress?o N-S. As conseq??ncias dos falhamentos na hidrologia subterr?nea s?o evidenciadas, principalmente, pela exist?ncia de varia??es bruscas da espessura saturada do Aq??fero Barreiras, decorrente do deslocamento vertical de blocos estruturais nestes falhamentos. Em particular, a oeste da Lagoa do Bonfim, mostrou-se que a principal frente de alimenta??o subterr?nea da lagoa est? associada a um aumento brusco da espessura do aq??fero decorrente dos rejeitos verticais de duas falhas. As estruturas s?o respons?veis ainda pelos limites da drenagem subterr?nea e, provavelmente, por inflex?es das superf?cies equipotenciais no mapa potenciom?trico da ?rea. No ?mbito da hidrologia superficial, os falhamentos condicionam os cursos de rios e riachos (anomalias hidrogr?ficas), limites superficiais e padr?es da rede de drenagem, assim como as formas e g?neses das principais lagoas da ?rea. A Lagoa do Bonfim, particularmente, possui sua g?nese e evolu??o relacionada ? a??o de duas estruturas, ressaltada pela forma ex?tica de seu espelho d ?gua (alongado segundo as dire??es NW e NE das referidas falhas), somada ? prov?vel intera??o com processos c?rsticos na seq??ncia carbon?tica mesoz?ica

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-14T19:08:15Z No. of bitstreams: 1 DanielEvoraDeQueiroz_DISSERT.pdf: 1637643 bytes, checksum: 5f07f026aca2b21db16fe4bc9812146a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-15T21:13:03Z (GMT) No. of bitstreams: 1 DanielEvoraDeQueiroz_DISSERT.pdf: 1637643 bytes, checksum: 5f07f026aca2b21db16fe4bc9812146a (MD5) / Made available in DSpace on 2016-01-15T21:13:03Z (GMT). No. of bitstreams: 1 DanielEvoraDeQueiroz_DISSERT.pdf: 1637643 bytes, checksum: 5f07f026aca2b21db16fe4bc9812146a (MD5) Previous issue date: 2014-06-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Microssismos s?o vibra??es cont?nuas na Terra registradas na faixa de frequ?ncia de mili Hertz para 1 Hz. Estas vibra??es s?o em sua maioria compostas de ondas Rayleigh e s?o mais fortes na faixa de frequ?ncia de 0.04 ? 1 Hz. Seus mecanismos de gera??es ainda s?o quest?es de debates, mas ? consenso que eles est?o relacionados com perturba??es atmosf?ricas e ondas oce?nicas de gravidade. O Arquip?lago de S?o Pedro e S?o Paulo (ASPSP) est? localizado na regi?o equatorial do Oceano Atl?ntico cerca de 1.100 km de dist?ncia da costa do nordeste brasileiro. O ASPSP ? composto por um conjunto de v?rias pequenas forma??es rochosas com uma ?rea total de aproximadamente 17.000 m?. Devido a sua localiza??o distante do continente, isolamento e aus?ncia de ru?dos provocados pela atividade humana, este local ? ideal para a medi??o de ru?do micross?smico e investiga??o de sua rela??o com algumas vari?veis clim?ticas e oceanogr?ficas. No ASPSP registramos microssismos prim?rios (PM) entre 0.04 - 0.12 Hz e microssismos secund?rios (SM) entre 0.12 - 0.4 Hz durante 10 meses em 2012 e 2013. As an?lises indicam uma boa correla??o entre o ru?do micross?smico na regi?o e uma depend?ncia do clima de ondas. Em particular, com inverno no hemisf?rio norte. Tamb?m ? mostrado que a maior parte do PM ? gerado no pr?prio ASPSP. O local de gera??o do SM depende do comportamento das vari?veis clim?ticas e oceanogr?ficas no hemisf?rio norte. / Microseisms are continuous vibrations pervasively recorded in the mili Hertz to 1 Hz frequency range. These vibrations are mostly composed of Rayleigh waves and are strongest in the 0.04 to 1 Hz frequency band. Their precise source mechanisms are still a matter of debate but it is agreed that they are related to atmospheric perturbations and ocean gravity waves. The Saint Peter Saint Paul Archipelago (SPSPA) is located in the equatorial region of the Atlantic Ocean about 1,100 km distant from the Brazilian northeastern coast. The SPSPA is composed by a set of several small rocky formations with a total area of approximately 17,000 m?. Due to its remote distance from the continent and the lack of cultural noise, this location is a unique location for measuring microseismic noise and to investigate its relation with some climate and oceanographic variables. In the SPSPA we have recorded both primary microseisms (PM) at 0.04 ? 0.12 Hz and the secondary microseisms (SM) at 0.12 ? 0.4 Hz during 10 months in 2012 and 2013. Our analysis indicates a good correlation between the microseismic noise in the region and a seasonal dependency. In particular, the winter in the northern hemisphere. We have also shown that most of the PM is generated in the SPSPA itself. The SM source location depends with the seasonal climatic and oceanographic variables in the northern hemisphere

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-10T21:36:15Z No. of bitstreams: 1 SuelenFerreiraDeSouza_DISSERT.pdf: 7511190 bytes, checksum: 0062c68fcd279e38ae2ec6c4dbde725a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-13T20:52:31Z (GMT) No. of bitstreams: 1 SuelenFerreiraDeSouza_DISSERT.pdf: 7511190 bytes, checksum: 0062c68fcd279e38ae2ec6c4dbde725a (MD5) / Made available in DSpace on 2016-05-13T20:52:31Z (GMT). No. of bitstreams: 1 SuelenFerreiraDeSouza_DISSERT.pdf: 7511190 bytes, checksum: 0062c68fcd279e38ae2ec6c4dbde725a (MD5) Previous issue date: 2015-08-12 / O estudo de bacias sedimentares envolve uma integra??o de informa??es adquiridas a partir da aplica??o de diversas metodologias. Os m?todos potenciais, gravim?trico e magn?tico, representam uma metodologia eficaz no estudo do arcabou?o tect?nico de bacias sedimentares a um custo relativamente barato, se comparado ?s demais t?cnicas. O presente trabalho apresenta a integra??o de diferentes t?cnicas avan?adas de processamento geof?sico em dados potenciais (Redu??o ao Polo, Matched Filter, Gradiente Horizontal e Inclina??o do Sinal Anal?tico), que auxiliaram grandemente na particulariza??o da express?o geof?sica das principais componentes estruturais do Rifte Potiguar e seu embasamento cristalino. Os resultados permitiram identificar claramente as bordas falhadas do Rifte Potiguar (Carnaubais, Apodi e Mulungu), assim como seus componentes internos, horsts Macau e Quixaba, e os grabens Apodi, Umbuzeiro e Boa Vista. As expressivas zonas de cisalhamentos do seu embasamento (Senador Pompeu, Jaguaribe, Portalegre, A?u, Flor?nia-?ngicos e Picu? Jo?o-C?mara) tamb?m foram evidenciadas pelo mapeamento geof?sico como extensos alinhamentos sigmoidais de dire??o NE-SW. A integra??o dos dados geof?sicos com dados geol?gicos permitiu a identifica??o de oito dom?nios tect?no-geof?sicos com o objetivo de se estabelecer o comportamento dos principais blocos crustais da Prov?ncia Borborema abaixo do pacote sedimentar. As respostas fornecidas pelas t?cnicas permitiram ainda a associa??o das estruturas acima citadas com as principais etapas de rifteamento pelos quais passou a bacia durante a sua complexa evolu??o. O trend NE-SW, que ocorre como o principal padr?o direcional nas regi?es adjacentes ao Rifte Potiguar e tamb?m em seu interior, evidencia uma forte influ?ncia de estruturas pr?-cambrianas na forma??o da bacia, assim como a deforma??o NW-SE nos diques Rio Cear?-Mirim, o truncamento de estruturas NE com a Falha de Apodi, e tamb?m o afastamento entre a Zona de Cisalhamento Portalegre e o Sistema de Falhas de Carnaubais, contribuem para hip?tese de propaga??o dos esfor?os da Margem Equatorial para o interior do continente. / The study of sedimentary basins involves an integration of information acquired from the application of different methodologies. The Potential Methods, gravity and magnetic represent an effective methodology to study the tectonic framework of sedimentary basins, at a relatively cheap cost than another techniques. The present work presents the integration of different advanced techniques of geophysical processing in potential data (Reducing to Pole, Matched Filter, Horizontal Gradient and Tilt Derivative) which greatly assisted in characterization of geophysical expression of the main structural components of Potiguar Rift and it tectonic framework. The results allowed clearly identify the failed edges of the Potiguar Rift (Carnaubais, Apodi e Mulungu faults), as well as its internal components, Macau and Quixaba horsts, and the Apodi, Umbuzeiro and Boa Vista grabens. The expressive shear zones of it basement (Senador Pompeu, Jaguaribe, Portalegre, A?u, Flor?nia-?ngicos e Picu? Jo?o-C?mara) they also were evidenced by geophysical mapping as extensive sigmoidal alignments of NE-SW direction. The integration of geophysical data with geological data allowed the identification of eight tectonic geophysicist domains, with purpose of establishing the behavior of main crustal blocks of the Borborema Province bellow of the sedimentary package. The results provided by techniques also allowed the association of the above mentioned structures with the main stages of rifting by which passed the basin during its complex evolution. The trend NE-SW, that occurs as the main directional pattern in the adjacent regions to the Potiguar Rift, and also inside evidence a strong control of precambrian structures in basin formation, as well as the NW-SE deformation in the Rio Cear?-Mirim dykes swarms, the truncation of NE structures with Apodi Fault, and also the separation between Portalegre Shear Zone and the Carnaubais System Faults, contribute to the hypothesis of propagation of the Equatorial Margin efforts into the continent.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-10T23:07:24Z No. of bitstreams: 1 CibeleRibeiroDaSilva_DISSERT.pdf: 4168823 bytes, checksum: 76c237aee7ce05bfb8f2b3f77e0b8a0c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-17T23:03:59Z (GMT) No. of bitstreams: 1 CibeleRibeiroDaSilva_DISSERT.pdf: 4168823 bytes, checksum: 76c237aee7ce05bfb8f2b3f77e0b8a0c (MD5) / Made available in DSpace on 2016-05-17T23:03:59Z (GMT). No. of bitstreams: 1 CibeleRibeiroDaSilva_DISSERT.pdf: 4168823 bytes, checksum: 76c237aee7ce05bfb8f2b3f77e0b8a0c (MD5) Previous issue date: 2013-04-30 / RESUMO: A presente disserta??o tem objetivo como investigar a improvisa??o - tal como ? realizada no contexto da Dan?a Contempor?nea - como possibilidade de prepara??o corporal do artista c?nico. Prop?e realizar uma reflex?o sobre o processo da prepara??o corporal proposto por mim atrav?s da observa??o dos procedimentos experimentados no Grupo de Pesquisa Corpo-devir, especialmente criado nessa pesquisa, que estudou e vivenciou a improvisa??o em dan?a e, ainda, apresentar relatos e reflex?es dos participantes sobre sua experi?ncia, com ?nfase especial na poss?vel contribui??o para a forma??o dos artistas da cena. Justifica-se, assim, no ensejo de que o artista c?nico usufrua dos conhecimentos trazidos pela pr?tica da dan?a e se perceba sujeito criador da pr?pria forma??o art?stica, e, ainda, que essa pr?tica possa contribuir com perspectivas art?stico-pedag?gicas do corpo c?nico, da cena e dos processos criativos nas artes c?nicas. O trabalho tem abordagem qualitativa com tratamento descritivo das observa??es e est? baseado em pesquisa bibliogr?fica, videogr?fica e som?tica dos procedimentos de improvisa??o em dan?a contempor?nea. Os principais interlocutores te?ricos dessa disserta??o s?o Gilles Deleuze, F?lix Guattari, Maurice Merleau-Ponty, Jorge Larossa, Jo?o Francisco Duarte Jr., Rudolf Laban e Klauss Vianna, sendo que os dois ?ltimos e o coletivo Judson Dance Theater contribuem ainda, com as concep??es metodol?gicas utilizadas nas oficinas. ABSTRACT: This master thesis aims to investigate the improvisation - as it is realized as the context of Contemporary Dance - as a possibility of body preparation of the scenic artist. It proposes to realize a reflection on the process of body preparation, proposed by me through the experiment procedures the observation with Grupo de Pesquisa Corpo-devir, specially formed in this research. This group studied and lived the improvisation in dance and also presented reports and reflections of the participants about their experience, giving special emphasis in the possible contribution for the formation of artists of the scene. In this way it is justified that the scenic artist enjoys the knowledge through the practice of the dance and realizes as being the creator of this own artistic formation. Also, the artist realizes that this practice may contribute with the artistic-pedagogic perspectives of the scenic group, of the scene and the creative processes in the scenic arts. The work has a qualitative approach, with descriptive treatment of observations, and it is based in bibliographical, video graphic and somatic of the improvisation procedures in contemporary dance. The main theoretical-practical interlocutors of this dissertation are Gilles Deleuze, F?lix Guattari, Maurice Merleau-Ponty, Jorge Larrosa, Jo?o Francisco Duarte Jr., Rudolf Laban and Klauss Vianna, being the last two and the collective Judson Dance Theater, still contribute with methodological concepts used in the workshops. / This master thesis aims to investigate the improvisation ? as it is realized as the context of Contemporary Dance - as a possibility of body preparation of the scenic artist. It proposes to realize a reflection on the process of body preparation, proposed by me through the experiment procedures the observation with Grupo de Pesquisa Corpo-devir, specially formed in this research. This group studied and lived the dance improvisation and also presented reports and reflections of the participants about their experience, giving special emphasis in the possible contribution for the formation of artists of the scene. In this way it is justified that the scenic artist enjoys the knowledge through the practice of the dance and realizes as being the creator of this own artistic formation. Also, the artist realizes that this practice may contribute with the artistic-pedagogic perspectives of the scenic group, of the scene and the creative processes in the scenic arts. The work has a qualitative approach, with descriptive treatment of observations, and it is based in bibliographical, video graphic and somatic of the improvisation procedures in contemporary dance. The main theoretical-practical interlocutors of this dissertation are Gilles Deleuze, F?lix Guattari, Maurice Merleau-Ponty, Jorge Larrosa, Jo?o Francisco Duarte Jr., Rudolf Laban and Klauss Vianna, being the last two and the collective Judson Dance Theater, still contribute with methodological concepts used in the workshops.

Made available in DSpace on 2014-12-17T14:57:43Z (GMT). No. of bitstreams: 1 AlyssonRFB.pdf: 2167882 bytes, checksum: 8299a168b4ffa71ad51d65356a2a5ae5 (MD5) Previous issue date: 2006-12-21 / The advantage in using vegetable fibres in place of synthetic fibres such as glass fibre, for reinforcements in composites are: biodegradability, low cost, low density, good tenacity, good thermal properties, low energy content and reduced use of instruments for its treatment or processing. Even though, problems related to low mechanical performance of some of the natural fibres, has caused difficulty in their direct application in structural elements. The use of alternative materials like hybrid composites has been encouraged, thus trying to better the structural performance of the composites with natural fibres. This work presents a comparative study of the strength and stiffness of hybrid composites with orthopthalic polyester matrix reinforced with E-fibre glass, jute and curau?. The experimental part includes uniaxial tension and three point bending tests to determine the mechanical properties of the final product. The hybrid composite was manufactured in a local industry and was in the form of laminates. All the samples were projected to withstand the possible structural applications as reservoirs and pipes. CH (laminated hybrid composite with glass and curau? fibres). The results obtained show clearly the influence of the hybridization in all the types tested and indicate a good mechanical performance of the composite with glass/curau? fibres in relation to the composite with glass fibres. Aspects in relation to the interfaces glass/curau? composites besides the fracture characteristics for all loading types were also analysed / As vantagens do uso de fibras vegetais sobre as fibras sint?ticas, como as fibras de vidro, no refor?o de comp?sitos s?o: biodegradabilidade, baixo custo, baixa densidade, boa tenacidade, boas propriedades t?rmicas e uso reduzido de instrumentos para o seu tratamento ou processamento. Por?m, problemas relacionados com o baixo desempenho mec?nico de algumas fibras naturais, t?m dificultado seu uso direto em elementos estruturais. Neste sentido, o aparecimento de materiais alternativos, como os comp?sitos h?bridos, vem sendo incentivado buscando-se melhorar o desempenho estrutural dos comp?sitos com fibras naturais. O presente trabalho de investiga??o apresenta um estudo comparativo da resist?ncia e rigidez de comp?sito de matriz poli?ster ortoft?lica refor?ada com fibras de vidro-E e h?brido com fibras naturais de curau?. A investiga??o experimental inclui testes de absor??o de umidade, tra??o uniaxial e de flex?o-em-tr?s-pontos para a determina??o das propriedades mec?nicas do produto final. Os comp?sitos de fibra de vidro e h?bridos s?o de fabrica??o industrial e foram desenvolvidos na forma de laminados. Todos foram projetados para atender poss?veis aplica??es estruturais como reservat?rios e tubula??es: Laminados de fibras de vidro (CV) e h?bridos (CH) (comp?sito laminado h?brido de fibras de vidro/curau?). Os refor?os utilizados nos comp?sitos foram na formas de tecidos aleat?rios (vidro-E) e mechas de fios cont?nuos (curau?). Os resultados obtidos mostram claramente a influ?ncia da hibridiza??o e meios de absor??o de umidade e indicam um bom desempenho mec?nico do comp?sito curau?/vidro. Tamb?m foram analisados aspectos referentes ? interface curau?/vidro e as caracter?sticas finais da fratura para todos os tipos de carregamentos estudados

Made available in DSpace on 2014-12-17T14:57:44Z (GMT). No. of bitstreams: 1 LeonardoPSR.pdf: 5835314 bytes, checksum: 12deb1964ac794f5dcc1b8fb3ba5e4c9 (MD5) Previous issue date: 2007-12-26 / The advantages of the use of vegetable fibers on the synthetic fibers, such as glass fibers, in the reinforcements in composites are: low cost, low density, good tenacity, good thermal properties and reduced use of instruments for their treatment or processing. However, problems related to poor performance of some mechanical natural fibers, have hindered its direct use in structural elements. In this sense, the emergence of alternative materials such as hybrids composites, involving natural and synthetic fibers, has been encouraged by seeking to improve the performance of structural composites based only on natural fibers. The differences between the physical, chemical and mechanical properties of these fibers, especially facing the adverse environmental conditions such as the presence of moisture and ultraviolet radiation, is also becoming a concern in the final response of these composites. This piece of research presents a comparative study of the strength and stiffness between two composite, both of ortoftalic polyester matrix, one reinforced with fibers of glass-E (CV) and other hybrid reinforced with natural fibers of curau? and fiberglass-E (CH). All the comparative study is based on the influence of exposure to UV rays and steam heated water in composites, simulating the aging environment. The conditions for the tests are accelerated through the use of the aging chamber. The composites will be evaluated through tests of uniaxial static mechanical traction and bending on three points. The composite of glass fiber and hybrid manufacturing industry are using the rolling manual (hand lay-up) and have been developed in the form of composites. All were designed to meet possible structural applications such as tanks and pipes. The reinforcements used in composites were in the forms of short fiber glass-E quilts (450g/m2 - 5cm) of continuous wires and fuses (whose title was of 0.9 dtex) for the curau? fibers. The results clearly show the influence of aging on the environmental mechanical performance of the composite CV and CH. The issues concerning the final characteristics of the fracture for all types of cargoes studied were also analyzed / As vantagens do uso de fibras vegetais sobre as fibras sint?ticas, como as fibras de vidro, no refor?o de comp?sitos s?o: baixo custo, baixa densidade, boa tenacidade, boas propriedades t?rmicas e uso reduzido de instrumentos para o seu tratamento ou processamento. Por?m, problemas relacionados com o baixo desempenho mec?nico de algumas fibras vegetais, t?m dificultado seu uso direto em elementos estruturais. Neste sentido, o aparecimento de materiais alternativos, como os comp?sitos h?bridos, envolvendo fibras sint?ticas e naturais, vem sendo incentivado buscando-se melhorar o desempenho estrutural dos comp?sitos a base s? de fibras vegetais. As diferen?as entre as propriedades f?sicas, qu?micas e mec?nicas dessas fibras, principalmente frente ?s condi??es ambientais adversas, como a presen?a de umidade e radia??o ultravioleta, vem se tornando uma preocupa??o a mais na resposta final desses comp?sitos. No presente trabalho de investiga??o apresenta-se um estudo comparativo da resist?ncia e rigidez entre dois comp?sitos, ambos de matriz poli?ster ortoft?lica, sendo um refor?ado com fibras de vidro-E (CV) e o outro h?brido refor?ado com fibras vegetais de curau? e fibra de vidro-E (CH). Todo o estudo comparativo teve como base a influ?ncia da exposi??o ? raios UV e vapor d ?gua aquecido nos comp?sitos, simulando o envelhecimento ambiental. As condi??es de ensaios s?o aceleradas atrav?s do uso da c?mara de envelhecimento. Os comp?sitos ser?o avaliados atrav?s de ensaios mec?nicos est?ticos de tra??o uniaxial e flex?o em tr?s pontos. Os comp?sitos de fibra de vidro e h?bridos s?o de fabrica??o industrial utilizando o processo de lamina??o manual (hand lay-up) e foram desenvolvidos na forma de comp?sitos. Todos foram projetados para atender poss?veis aplica??es estruturais, como reservat?rios e tubula??es. Os refor?os utilizados nos comp?sitos foram na formas de mantas de fibras vidro-E curtas (450g/m2 5cm) e mechas de fios cont?nuos (cujo t?tulo foi de 0,9 dtex) para as fibras de curau?. Os resultados obtidos mostram claramente a influ?ncia do envelhecimento ambiental no desempenho mec?nico dos comp?sitos CV e CH. Tamb?m foram analisados aspectos referentes ?s caracter?sticas finais da fratura para todos os tipos de carregamentos estudados

Made available in DSpace on 2014-12-17T14:57:46Z (GMT). No. of bitstreams: 1 MirtaniaAL.pdf: 1813042 bytes, checksum: 3d26a66f383220285205f479f11b4656 (MD5) Previous issue date: 2009-09-27 / This research is based, at first, on the seeking of alternatives naturals reinforced in place of polymeric composites, also named reinforced plastics. Therein, this work starts with a whole licuri fiber micro structural characterization, as alternative proposal to polymeric composites. Licuri fiber is abundant on the Bahia state flora, native from a palm tree called Syagrus Coronata (Martius) Beccari. After, it was done only licuri fiber laminar composite developing studies, in order to know its behavior when impregnated with thermofix resin. The composite was developed in laminar structure shape (plate with a single layer of reinforcement) and produced industrially. The layer of reinforcement is a fabric-fiber unidirectional of licuri up in a manual loom. Their structure was made of polyester resin ortofit?lica (unsaturated) only reinforced with licuri fibers. Fiber characterization studies were based on physical chemistry properties and their constitution. It was made by tension, scanning electron microscopy (SEM), x-ray diffraction (RDX) and thermal analyses (TG and DTA) tests, besides fiber chemistry analyses. Relating their mechanical properties of strength and hardness testing, they were determined through unit axial tension test and flexion in three points. A study in order to know fiber/matrix interface effects, in the final composites results, was required. To better understand the mechanical behavior of the composite, macroscopic and microscopic optical analysis of the fracture was performed / Esta investiga??o baseia-se, em principio, na busca de refor?os naturais alternativos aos comp?sitos polim?ricos, tamb?m denominados de pl?sticos refor?ados. Neste sentido, o presente trabalho de pesquisa se inicia com um completo estudo de caracteriza??o micro estrutural da fibra de licuri, essa como proposta alternativa de refor?o aos comp?sitos polim?ricos. A fibra de licuri ? abundante na flora do estado da Bahia e origin?ria da palmeira denominada Syagrus Coronata (Martius) Beccari. Em seguida, foi realizado um estudo do desenvolvimento de um comp?sito laminar somente a base de fibras de licuri, de forma a se conhecer o comportamento da fibra quando impregnada com resina termofixa. O comp?sito foi desenvolvido na forma de estrutura laminar (placa com uma ?nica l?mina de refor?o) e fabricado industrialmente. A l?mina de refor?o ? de um tecido unidirecional de fibras de licuri confeccionado em um tear manual. O comp?sito tem em sua estrutura resina poli?ster ortofit?lica (insaturada) refor?ada somente com fibras de licuri. O estudo da caracteriza??o da fibra teve como base a determina??o das propriedades f?sicas, qu?micas e de constitui??o. As mesmas foram realizadas atrav?s dos ensaios de: tra??o uniaxial, an?lise por microscopia eletr?nica de varredura (MEV), ensaio de difra??o de raios X (RDX), an?lises t?rmicas (TG e DTA), al?m da an?lise qu?mica das fibras. Com rela??o ?s propriedades mec?nicas de resist?ncia e rigidez do comp?sito, estas foram determinadas atrav?s dos ensaios de tra??o uniaxial e flex?o em tr?s pontos. Um estudo com o objetivo de conhecer a influ?ncia da ader?ncia da interface fibra/matriz, na resposta final do comp?sito, se fez necess?rio. Para melhor entendimento do comportamento mec?nico do comp?sito, an?lises macrosc?picas e microsc?picas ?pticas da fratura foram realizadas

Made available in DSpace on 2014-12-17T14:57:50Z (GMT). No. of bitstreams: 1 RannierMM.pdf: 3580955 bytes, checksum: f892200d861ab62414259c44c459e1b9 (MD5) Previous issue date: 2009-03-30 / The use of polymer based coatings is a promising approach to reduce the corrosion problem in carbon steel pipes used for the transport of oil and gas in the oil industry. However, conventional polymer coatings offer limited properties, which often cannot meet design requirements for this type of application, particularly in regard to use temperature and wear resistance. Polymer nanocomposites are known to exhibit superior properties and, therefore, offer great potential for this type of application. Nevertheless, the degree of enhancement of a particular property is greatly dependent upon the matrix/nanoparticle material system used, the matrix/nanoparticle interfacial bonding and also the state of dispersion of the nanoparticle in the polymer matrix. The objective of the present research is to develop and characterize polymer based nanocomposites to be used as coatings in metallic pipelines for the transportation of oil and natural gas. Epoxy/SiO2 nanocomposites with nanoparticle contents of 2, 4, and 8 wt % were processed using a high-energy mill. Modifications of the SiO2 nanoparticles‟ surfaces with two different silane agents were carried out and their effect on the material properties were investigated. The state of dispersion of the materials processed was studied using Scanning and Transmission Electron Microscopy (SEM and TEM) micrographs. Thermogravimetric analysis (TG) were also conducted to determine the thermal stability of the nanocomposites. In addition, the processed nanocomposites were characterized by dynamic mechanical analysis (DMA) to investigate the effect of nanoparticles content and silane treatment on the viscoelastic properties and on the glass transition temperature. Finally, wear tests of the pin-on-disc type were carried out to determine the effects of the nanoparticles and the silane treatments studied. According to the results, the addition of SiO2 nanoparticles treated with silane increased the thermal stability, the storage modulus and Tg of the epoxy resin and decreased wear rate. This confirms that the interaction between the nanoparticles and the polymer chains plays a critical role on the properties of the nanocomposites / A utiliza??o de pol?mero como revestimento ? algo promissor para redu??o de corros?o interna de dutos de a?o carbono utilizados no transporte de petr?leo e g?s natural na ind?stria petrol?fera. No entanto, os revestimentos polim?ricos convencionais apresentam propriedades limitadas, que muitas vezes n?o podem satisfazer os requisitos necess?rios, particularmente em rela??o ? temperatura empregada e ao desgaste. Nanocomp?sitos polim?ricos s?o conhecidos por apresentarem propriedades superiores e, portanto, apresentam potencial para este tipo de aplica??o. Por?m, o grau de refor?o de uma propriedade particular ? fortemente dependente dos materiais utilizados no sistema matriz/nanopart?culas, da liga??o interfacial e, tamb?m, do estado de dispers?o das nanopart?culas na matriz polim?rica. O objetivo do presente trabalho ? desenvolver e caracterizar nanocomp?sitos polim?ricos para utiliza??o como revestimento de dutos met?licos da ind?stria do petr?leo. Nanocomp?sitos Ep?xi/SiO2 com 2, 4 e 8% em massa de nanopart?culas foram processados usando um moinho de alta energia. Modifica??es nas superf?cies das nanopart?culas de SiO2 foram realizadas com dois tipos diferentes de silano e seus efeitos sobre as propriedades dos materiais foram investigados. O estado de dispers?o do material processado foi estudado usando micrografias de Microscopia Eletr?nica de Varredura e de Transmiss?o (MEV e MET). Foram realizadas an?lises termogravim?tricas (TG) para verificar a estabilidade t?rmica dos nanocomp?sitos. Al?m disso, foram realizadas an?lises din?mico-mec?nicas (DMA) para estudar os efeitos das nanopart?culas e dos tratamentos com silano nas propriedades viscoel?sticas e na temperatura de transi??o v?trea (Tg). Por fim, testes de desgaste do tipo esfera-disco foram realizados para determinar os efeitos da adi??o de nanopart?culas e dos diferentes tipos de tratamento de silaniza??o estudados. De acordo com os resultados, a adi??o nanopart?culas de SiO2 tratadas com silano aumentou a temperatura de in?cio de degrada??o do pol?mero, o m?dulo de armazenamento e a Tg da resina ep?xi, al?m de ter proporcionado uma menor taxa de desgaste. Isto confirma que a intera??o entre as nanopart?culas e as cadeias polim?ricas desempenha um papel cr?tico sobre as propriedades dos nanocomp?sitos

Made available in DSpace on 2014-12-17T14:58:07Z (GMT). No. of bitstreams: 1 SistanleyJLB_DISSERT.pdf: 3362424 bytes, checksum: 30d67bc0b13dba47c7002133ab1bb63d (MD5) Previous issue date: 2011-06-20 / This research presents an approach to the addition of curau? fibers and licuri fibers in a polypropylene resin matrix, such as an alternative proposal to reinforce the polymeric composites. Fiber content of 0 %, 5 %, 10 %, and 20% were analyzed for verification of their mechanical properties comparing them, inclusive with the properties of polypropylene. The grainulated biocomposites had been prepared in an extrusora. The test bodies had been molded by injection and submitted to the mechanical essays uniaxial traction, flexion on three points, impact, in addition to thermal tests (HDT). These biocomposites had been also subjected the essay physicist-chemistry index of fluidity (IF). It was observed that the biocomposites of PP with 20% curau?, obtained bigger increase in the modulus of elasticity and a bigger reduction in the resistance to the impact. In the mechanical behavior, for all the biocomposites, these were increases in values of the limit of drainage and tension of rupture, when tested by uniaxial traction, as they added the fibers. Another important point was the increase of the resistance the flexion. It was also noted that the addition of fibers reduced the thermal degradation of the mixture natural fibers / polypropylene. / Esta pesquisa apresenta uma abordagem da adi??o de fibras de licuri e curau? em uma matriz de resina de polipropileno, essa como uma proposta alternativa de refor?o aos comp?sitos polim?ricos. Teores de fibras de 0 %, 5 %, 10 %, e 20 % foram analisados para verifica??o de suas propriedades mec?nicas comparando-as, inclusive com as propriedades do polipropileno. Os biocomp?sitos granulados foram preparados em uma extrusora. Os corpos de prova foram moldados por inje??o e submetidos aos ensaios mec?nicos de tra??o uniaxial, flex?o em tr?s pontos, impacto, al?m de ensaios t?rmicos (HDT). Estes biocomp?sitos tamb?m foram submetidos a ensaio f?sico-qu?mico de ?ndice de fluidez (IF). Observou-se que os biocomp?sitos de PP com 20% curau? obteve maior aumento no m?dulo de elasticidade, e uma maior diminui??o na resist?ncia ao impacto. No comportamento mec?nico, para todos os biocomp?sitos, houve acr?scimos nos valores do limite de escoamento e tens?o de ruptura quando ensaiados por tra??o uniaxial, ? medida que se adicionavam as fibras. Outro ponto importante foi o aumento da resist?ncia ? flex?o. Verificou-se tamb?m que a adi??o de fibras reduziu a degrada??o t?rmica da mistura fibras naturais / polipropileno.