Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-14T21:40:34Z No. of bitstreams: 1 RonycleiRaimundoDaSilva_DISSERT.pdf: 1911613 bytes, checksum: bc12b6ba49c786087e656fbc0870de75 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-17T18:43:16Z (GMT) No. of bitstreams: 1 RonycleiRaimundoDaSilva_DISSERT.pdf: 1911613 bytes, checksum: bc12b6ba49c786087e656fbc0870de75 (MD5) / Made available in DSpace on 2015-12-17T18:43:16Z (GMT). No. of bitstreams: 1 RonycleiRaimundoDaSilva_DISSERT.pdf: 1911613 bytes, checksum: bc12b6ba49c786087e656fbc0870de75 (MD5) Previous issue date: 2014-01-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / O sistema Mo-Cu ? um comp?sito usado na ind?stria el?trica como material para contato el?trico e resist?ncia de eletrodo de solda assim como dissipador de calor e absorvedor de microondas em dispositivos microeletr?nicos. O emprego desse material em tais aplica??es se deve as excelentes propriedades de condutividade t?rmica e el?trica e a possibilidade de ajuste do seu coeficiente de expans?o t?rmica para satisfazer aqueles dos materiais usados como substratos dos semicondutores na ind?stria micoreletr?nica. A metalurgia do p? atrav?s dos processos de moagem, conforma??o por prensagem e sinteriza??o ? uma t?cnica vi?vel para consolida??o desse tipo de material. Entretanto, a m?tua insolubilidade de ambos as fases e a baixa molhabilidade do Cu l?quido sobre o Mo dificultam a sua densifica??o. A moagem de alta energia ? uma t?cnica de prepara??o de p?s usada para produzir p?s comp?sitos nanocristalinos, com fase amorfa ou solu??o s?lida estendida, os quais aumentam a sinterabilidade de sistemas imisc?veis como o Mo-Cu. Este trabalho investiga a influ?ncia do heptamolibdato de am?nia (HMA) e da moagem de alta energia na prepara??o de um p? comp?sito HMA-20%Cu assim como o efeito desta prepara??o na densifica??o e estrutura do comp?sito Mo-Cu produzido. P?s de HMA e Cu na propor??o de 20% em massa de Cu foram preparados pelas t?cnicas de mistura mec?nica e moagem de alta energia em um moinho planet?rio. Estes foram mo?dos por at? 50 horas. Para observar a evolu??o das caracter?sticas das part?culas, amostras de p?s foram colhidas ap?s 2, 10, 15, 20, 30 e 40 horas de moagem. Amostras cil?ndricas com 5 e 8 mm de di?metro e 3 a 4 mm de espessura foram obtidas por prensagem a 200 MPa tanto para os p?s misturados como para os mo?dos. Tais amostras foram sinterizada a 1200 oC por 60 minutos sob uma atmosfera de H2. Para verificar o efeito da taxa de aquecimento na estrutura do material durante a decomposi??o e redu??o do HMA, foram usadas as taxas de 2, 5 e 10 oC/min.. Os p?s e as estruturas dos corpos sinterizados foram caracterizados por DRX, MO, MEV e EDS. A densidade dos corpos verdes e sinterizados foi medida usando o m?todo geom?trico (massa/volume). Medidas de microdureza vickers com carga de 20 N durante 15 s foram efetuadas nas estruturas sinterizadas. A densidade das estruturas sinterizadas a 10 oC/min. alcan?ou 99 % da densidade te?rica, em quanto a densidade das estruturas sinterizadas a 2 oC/min. atingiu somente 90 % da densidade te?rica. / The Cu-Mo system is a composite used in the electrical industry as material for electrical contact and resistance welding electrode as well as the heat sink and microwave absorber in microelectronic devices. The use of this material in such applications is due to the excellent properties of thermal and electrical conductivity and the possibility of adjustment of its coefficient of thermal expansion to meet those of materials used as substrates in the semiconductor micoreletr?nic industry. Powder metallurgy through the processes of milling, pressing shaping and sintering is a viable technique for consolidation of such material. However, the mutual insolubility of both phases and the low wettability of liquid Cu on Mo impede its densification. However, the mutual insolubility of both phases and the low wettability of liquid Cu on Mo impede its densification. The mechanical alloying is a technique for preparation of powders used to produce nanocrystalline composite powder with amorphous phase or extended solid solution, which increases the sinterability immiscible systems such as the Mo-Cu. This paper investigates the influence of ammonium heptamolybdate (HMA) and the mechanical alloying in the preparation of a composite powder HMA-20% Cu and the effect of this preparation on densification and structure of MoCu composite produced. HMA and Cu powders in the proportion of 20% by weight of Cu were prepared by the techniques of mechanical mixing and mechanical alloying in a planetary mill. These were milled for 50 hours. To observe the evolution of the characteristics of the particles, powder samples were taken after 2, 10, 15, 20, 30 and 40 hours of milling. Cylindrical samples 5 to 8 mm in diameter and 3 to 4 mm thickness were obtained by pressing at 200 MPa to the mixed powders so as to ground. These samples were sintered at 1200 ? C for 60 minutes under an atmosphere of H2. To determine the effect of heating rate on the structure of the material during the decomposition and reduction of HMA, rates of 2, 5 and 10 ? C / min were used .. The post and the structures of the sintered samples were characterized by SEM and EDS. The density of the green and sintered bodies was measured using the geometric method (weight / volume). Vickers microhardness with a load of 1 N for 15 s were performed on sintered structures. The density of the sintered structures 10 ? C / min. reached 99% of theoretical density, how the density of sintered structures to 2 ? C / min. reached only 90% of the theoretical density

Made available in DSpace on 2014-12-17T14:06:53Z (GMT). No. of bitstreams: 1 CarlosRG.pdf: 3095179 bytes, checksum: 8f85422621006a6dd669bfabb5747ac9 (MD5) Previous issue date: 2009-08-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Although already to exist alternative technique and economically viable for destination of used tires, quantitative data on properties of constructive elements that use the rubber waste as aggregate still are restricted. In the present work, the waste proceeding from industry of retreading as material for manufacture of composite destined to the production of constructive elements was considered. Mechanical and thermal properties of mortar had been analyzed Portland cement with addition of waste without treatment, in the ratios of 10%, 20% and 30% in mass in relation to the mass of the cement, substituting the aggregate in the trace in mortar 1:5 mass cement and sand. The size of the used residue varied between 0,30mm and 4,8mm (passing in the bolter 4,8mm and being restrained in the one of 0,30mm), being it in the formats fibers and granular. The influences of the size and the percentage of residue added to the mortar (in substitution to the aggregate) in the thermal and mechanical properties had been considered. Assays of body-of-test in thestates had been become fullfilled cool (consistency index) and hardened (absorption of water for capillarity, strength the compression, traction and strength flexural). The work is centralized in the problem of the relation thermal performance /strength mechanics of used constructive systems in regions of low latitudes (Been of the Piau?), characterized for raised indices of solar radiation. / Apesar de j? existirem alternativas t?cnica e economicamente vi?veis para destina??o de pneum?ticos usados, dados quantitativos sobre propriedades de elementos construtivos que utilizam o res?duo de borracha como agregado ainda s?o restritos. No presente trabalho, considerou-se o res?duo proveniente de ind?stria de recauchutagem como material para fabrica??o de comp?sito destinado ? produ??o de elementos construtivos. Foram analisadas propriedades mec?nicas e t?rmicas de argamassa de cimento Portland com adi??o de res?duo sem tratamento, nas propor??es de 10%, 20% e 30% em massa em rela??o ? massa do cimento, substituindo o agregado no tra?o em massa 1:5 de argamassa cimento e areia. A granulometria do res?duo utilizado variou entre 0,30mm e 4,8mm (passando na peneira 4,8mm e ficando retido na de 0,30mm), sendo ele nos formatos fibroso e granular. Consideraram-se as influ?ncias da granulometria e do percentual de res?duo adicionado ? argamassa (em substitui??o ao agregado) nas propriedades t?rmicas e mec?nicas. Realizaram-se ensaios de corpos-deprova nos estados fresco (?ndice de consist?ncia) e endurecido (absor??o de ?gua por capilaridade, resist?ncia a compress?o e tra??o). O trabalho est? focado no problema da rela??o desempenho t?rmico /resist?ncia mec?nica de sistemas construtivos utilizados em regi?es de baixas latitudes (Estado do Piau?), caracterizadas por elevados ?ndices de radia??o solar.

Made available in DSpace on 2014-12-17T14:07:08Z (GMT). No. of bitstreams: 1 ErikSS_DISSERT.pdf: 3248804 bytes, checksum: 7241bc799da79c157edae8da7a7966cc (MD5) Previous issue date: 2013-04-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Currently the search for new materials with properties suitable for specific applications has increased the number of researches that aim to address market needs. The poly (methyl methacrylate) (PMMA) is one of the most important polymers of the family of polyacrylates and polymethacrylates, especially for its unique optical properties and weathering resistance, and exceptional hardness and gloss. The development of polymer composites by the addition of inorganic fillers to the PMMA matrix increases the potential use of this polymer in various fields of application. The most commonly used inorganic fillers are particles of silica (SiO2), modified clays, graphite and carbon nanotubes. The main objective of this work is the development of PMMA/SiO2 composites at different concentrations of SiO2, for new applications as engineering plastics. The composites were produced by extrusion of tubular film, and obtained via solution for application to commercial PMMA plates, and also by injection molding, for improved the abrasion and scratch resistance of PMMA without compromising transparency. The effects of the addition of silica particles in the polymer matrix properties were evaluated by the maximum tensile strength, hardness, abrasion and scratch resistance, in addition to preliminary characterization by torque rheometry and melt flow rate. The results indicated that it is possible to use silica particles in a PMMA matrix, and a higher silica concentration produced an increase of the abrasion and scratch resistance, hardness, and reduced tensile strength / Atualmente a busca por novos materiais com propriedades adequadas para aplica??es espec?ficas vem aumentando o n?mero de pesquisas que visam suprir as necessidades do mercado. O poli(metacrilato de metila) (PMMA) ? um dos pol?meros mais importantes da fam?lia dos poliacrilatos e polimetacrilatos, principalmente pelas suas inigual?veis propriedades ?pticas e resist?ncia ?s intemp?ries, al?m de excepcional dureza e brilho. O desenvolvimento de comp?sitos polim?ricos por meio da adi??o de cargas inorg?nicas ? matriz de PMMA aumenta o potencial de uso deste pol?mero em diferentes ?reas de aplica??o. Dentre as cargas inorg?nicas mais utilizadas, podem-se destacar as part?culas de s?lica (SiO2), argilas modificadas, grafite e nanotubos de carbono. O objetivo principal deste trabalho ? o desenvolvimento de comp?sitos PMMA/SiO2, em diferentes concentra??es, para novas aplica??es como pl?stico de engenharia. Os comp?sitos foram produzidos por meio de extrus?o de filme tubular, e obtidos via solu??o, para aplica??o em chapas de PMMA comercial, e tamb?m por moldagem por inje??o, buscando o aumento da resist?ncia ? abras?o e ao risco do PMMA, sem comprometer a transpar?ncia. Os efeitos causados pela adi??o das part?culas de s?lica nas propriedades da matriz polim?rica foram avaliados atrav?s da resist?ncia m?xima ? tra??o, dureza, resist?ncia ? abras?o e ao risco, al?m das caracteriza??es preliminares por reometria de torque e ?ndice de fluidez. Os resultados indicaram que ? poss?vel utilizar part?culas de s?lica em uma matriz de PMMA, e que uma maior concentra??o de s?lica promoveu um aumento da resist?ncia ? abras?o e ao risco, dureza, e reduziu a resist?ncia m?xima ? tra??o

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-14T18:45:29Z No. of bitstreams: 1 HerikDantasDeLima_DISSERT.pdf: 4131924 bytes, checksum: 277ee7a89b9043637734f077d15e5432 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-15T18:02:24Z (GMT) No. of bitstreams: 1 HerikDantasDeLima_DISSERT.pdf: 4131924 bytes, checksum: 277ee7a89b9043637734f077d15e5432 (MD5) / Made available in DSpace on 2016-01-15T18:02:24Z (GMT). No. of bitstreams: 1 HerikDantasDeLima_DISSERT.pdf: 4131924 bytes, checksum: 277ee7a89b9043637734f077d15e5432 (MD5) Previous issue date: 2014-12-19 / Existe uma grande dificuldade na forma??o de um comp?sito do metal refrat?rio de ni?bio com o cobre. Isto se deve ao fato de que o sistema Nb-Cu ? quase mutuamente imisc?vel, podendo ser desprezada a solubilidade entre eles. Estas propriedades dificultam ou impedem a obten??o de estruturas homog?neas e de alta densidade, convencionalmente preparadas. Este trabalho tem por objetivo analisar a utiliza??o do processo de moagem de alta energia (MAE) para transpor estas dificuldades naturais, no que se refere ? densifica??o dos corpos sinterizados. A MAE e a prensagem foram utilizadas na prepara??o dos p?s, para a obten??o de uma fina e homog?nea distribui??o do tamanho dos gr?os. Quatro cargas de p?s de Nb e Cu contendo 15% em massa de Cu foram ent?o mo?dos por MAE em um moinho de bolas tipo planet?rio, sob diferentes per?odos e velocidades de moagem. Os resultados obtidos pela MAE foram analisados atrav?s da microscopia eletr?nica de varredura (MEV), de acordo com os par?metros de tempo e velocidade de moagem. As amostras foram compactadas sob press?o de 200 MPa, em seguida foram sinterizadas por fase l?quida em um forno ? v?cuo nas temperaturas de 1100?C/60 min e 1200?C/60 min. Depois foi utilizada a t?cnica de caracteriza??o de difra??o de raios-X para a identifica??o das fases. As microestruturas das amostras sinterizadas foram observadas e avaliadas atrav?s de microscopia eletr?nica de varredura (MEV). Ensaios de Microdureza Vickers foram realizados, obtendo maiores valores para os corpos sinterizados nos maiores tempos de moagem dos p?s e para as maiores velocidades de moagem. Foi verificado que a sinteriza??o por fase l?quida das amostras que foram processadas por MAE, produziu no final uma estrutura homog?nea e densificada em 77,4% em rela??o ao valor da densidade te?rica do comp?sito / There is great difficulty in forming a composite refractory metal niobium with copper. This is due to the fact that Nb-Cu system is almost mutually immiscible and may be neglected solubility between them. These properties hinder or prevent obtaining homogeneous and high-density structures, conventionally prepared. This study aims to analyze the use of high-energy milling process (MAE) to implement these natural difficulties, with regard to the densification of the sintered bodies. The MAE and the press were used in the preparation of powders, to obtain a fine and homogeneous distribution of the grain size. Four loads Nb and Cu powders containing 15% by weight of Cu were then milled for MAE in a planetary type ball mill under various milling times and speeds. The results obtained by MAE were analyzed by scanning electron microscopy (SEM), according to the parameters of time and grinding speed. The samples were compacted under pressure of 200 MPa, were then sintered in liquid phase in a vacuum furnace at temperatures of 1100 ? C / 60 min and 1200 ? C / 60 min. Then it was used to characterize diffraction of X-rays to identify the phases. The microstructures of the sintered samples were observed and evaluated using scanning electron microscopy (SEM). Vickers Microhardness tests were performed, obtaining higher values for the sintered bodies in the largest of the post milling times and the larger grinding speeds. It was found that the liquid phase sintering of the samples that were processed by MAE produced at the end of a homogeneous and densified structure in 77,4% relative to the value of the theoretical density of the composite

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-10T21:07:59Z No. of bitstreams: 1 LucianoLeonardoLopesCosta_DISSERT.pdf: 2685807 bytes, checksum: cd44bd3b6242d63070197e5e8c9d88a2 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-12T23:35:09Z (GMT) No. of bitstreams: 1 LucianoLeonardoLopesCosta_DISSERT.pdf: 2685807 bytes, checksum: cd44bd3b6242d63070197e5e8c9d88a2 (MD5) / Made available in DSpace on 2016-05-12T23:35:09Z (GMT). No. of bitstreams: 1 LucianoLeonardoLopesCosta_DISSERT.pdf: 2685807 bytes, checksum: cd44bd3b6242d63070197e5e8c9d88a2 (MD5) Previous issue date: 2015-08-12 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Tendo em vista a crescente busca por materiais que possam cada vez mais melhorar a efici?ncia de isolantes t?rmicos e que n?o causem agress?o ao meio ambiente, temos a utiliza??o da palha da carna?ba como uma alternativa de refor?o em comp?sitos de isola??o t?rmica. O comp?sito ? formado por fibras naturais da folha da carna?ba que possui propriedades f?sico-qu?micas desej?veis para ser utilizado como isolante t?rmico e o min?rio Caulim, que se caracteriza por ser quimicamente inerte e possuir baixa condutividade t?rmica. O comp?sito citado foi submetido a ensaios para determinar a sua condutividade t?rmica, densidade e resist?ncia ? temperatura. As propriedades f?sicas, estruturais e morfol?gicas das mat?rias-primas foram investigadas atrav?s de an?lises de termogravimetria, difra??o de raios X, fluoresc?ncia de raios X e microscopia eletr?nica de varredura. / Thinking about the growing search for materials than can improve the efficiency of thermal insulations, and that do not cause aggressions to the environment, we decided to use the leaf of the carnauba as an alternative reinforcement in composites of thermal insulation. The composite is formed by natural fibers of leaves of the carnauba, that possesses good physicochemical properties to work as a thermal insulation and the minerium caulim, that is characterized for being chemical inert and possesses low thermal conductivity. The carna?ba straw acquired was-covered with impurities, it was subjected to various washing processes for these impurities do not interfere in the tests, the caulimwas used without any treatment for their processing. After cleaning, the straw was milled in a knife mill to be in the form of powder, this powder was mixed with kaolin to be more homogeneous, the mixture was properly hydrated and pressed to make specimenfor testing.The composite was divided into formulations of 10%, 30% and 50%, this value indicates the percentage of the fiber mass of the carnauba powderper total mass of the composite, after that, the specimens were manufactured by the pressing method. The specimens have been tested to determine conductivity, resistance, diffusivity. Analyses of thermogravimetry, x-ray diffraction, x-ray fluorescence were done, and a compression test to determine whether it could be used in wall cladding. The composite showed satisfactory results in their thermal characteristics, the composite showed satisfactory results in their thermal characteristics , with an operating range of up to 150 ? C and an average thermal conductivity of 0.199 W /m.K and quite feasible in the item cost-effective, but somewhat limited by their place of application.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-03T23:57:10Z No. of bitstreams: 1 ItailzaGomesDaRocha_DISSERT.pdf: 3542376 bytes, checksum: feceaf0a2a5196b154b6fcc7af590782 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-07T21:10:55Z (GMT) No. of bitstreams: 1 ItailzaGomesDaRocha_DISSERT.pdf: 3542376 bytes, checksum: feceaf0a2a5196b154b6fcc7af590782 (MD5) / Made available in DSpace on 2016-06-07T21:10:55Z (GMT). No. of bitstreams: 1 ItailzaGomesDaRocha_DISSERT.pdf: 3542376 bytes, checksum: feceaf0a2a5196b154b6fcc7af590782 (MD5) Previous issue date: 2015-09-08 / Atualmente se observa uma grande busca por materiais originados de fontes renov?veis. As fibras vegetais como refor?o para matrizes polim?ricas, tem sido uma alternativa para substituir fibras sint?ticas, por serem biodegrad?veis e de baixo custo. Este trabalho objetiva desenvolver um material comp?sito de resina ep?xi refor?ado com fibra de curau? e aditivo retardante de chama de alumina trihidratada (hidr?xido de alum?nio - Al(OH)3), que foi utilizado em propor??es de 10%, 20% e 30% do volume total do comp?sito. As fibras de curau? passaram por um processo de limpeza com um banho alcalino de hidr?xido de s?dio (NaOH), paralelizadas atrav?s de cardagem manual e cortadas de acordo com o comprimento predefinido. Foram moldados comp?sitos com fibras de 30cm e com fra??o volum?trica de 20% de fibra no Lossy Mould. Os comp?sitos foram preparados no Laborat?rio de Engenharia T?xtil da UFRN. Os testes de resist?ncia ao fogo foram realizados no laborat?rio de engenharia de materiais da UFRN. Para medir o desempenho do material, foram realizados ensaios de resist?ncia ? tra??o e flex?o, com as amostras que foram posteriormente analisadas no aparelho de Microscopia Eletr?nico de Varredura (MEV). Os comp?sitos apresentaram bom desempenho mec?nico, e foi observado que a adi??o do agente retardante de chama influenciou nas propriedades mec?nicas, e em alguns casos, deixando o comp?sito mais fr?geis a ruptura. Esses resultados mec?nicos foram submetidos ao teste estat?stico Qui-Quadrado ao n?vel de signific?ncia de 5% para verificar poss?veis diferen?as entre ao grupos de comp?sitos. O teste de flamabilidade foi realizado baseado na norma Underwriter's Laboratory 94 e o material apresentou um resultado satisfat?rio, tendo a sua taxa m?dia de queima (mm/min) diminuindo com o aumento da adi??o do retardante de chamas nos comp?sitos. / Currently, there is a great search for materials derived from renewable sources. The vegetable fibers as reinforcement for polymer matrixes, has been used as an alternative to replace synthetic fibres, being biodegradable and of low cost. The present work aims to develop a composite material with epoxy resin reinforced with curau? fibre with the addition of alumina trihydrate (aluminum hydroxide, Al(OH)3) as a flame retardant, which was used in proportions of 10 %, 20% and 30% of the total volume of the composite. The curau? fibers have gone through a cleaning process with an alkaline bath of sodium hydroxide (NaOH ), parallelized by hand and cut carding according to the default length . They were molded composites with fibers 30cm. Composites were molded in a Lossy Mold with unidirectional fibres in the proportion of 20% of the total volume of the composite. The composites were prepared in the Chemical Processing Laboratory of the Textile Engineering Department at UFRN. To measure the performance of the material, tests for the resistance to traction and flexion were carried out. with samples that were later analyzed in the Electronic Microscopy Apparatus (SEM ). The composites showed good mechanical properties by the addition of flame retardant and in some cases, leaving the composite more vulnerable to breakage. These mechanical results were analyzed by chi-square statistical test at the 5% significance level to check for possible differences between the composite groups. Flammability testing was conducted based on the standard Underwriters Laboratory 94 and the material showed a satisfactory result taking their average burn rate (mm / min) decreasing with increasing addition of the flame retardant composite.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-23T20:06:05Z No. of bitstreams: 1 MaraisaCristianeDeOliveiraLeite_DISSERT.pdf: 2733334 bytes, checksum: d086f67ef0d47e95e151ff9ad376bcd7 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-27T20:29:13Z (GMT) No. of bitstreams: 1 MaraisaCristianeDeOliveiraLeite_DISSERT.pdf: 2733334 bytes, checksum: d086f67ef0d47e95e151ff9ad376bcd7 (MD5) / Made available in DSpace on 2016-06-27T20:29:13Z (GMT). No. of bitstreams: 1 MaraisaCristianeDeOliveiraLeite_DISSERT.pdf: 2733334 bytes, checksum: d086f67ef0d47e95e151ff9ad376bcd7 (MD5) Previous issue date: 2015-12-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Este trabalho objetiva fabricar e caracterizar um comp?sito hibrido pl?stico, com matriz ? base de resina de poli?ster isoft?lica e tendo como refor?o fibras de vidro e o endocarpo do coco seco (Cocos Nuc?fera Linn) na forma de particulado como carga. O comp?sito foi confeccionado industrialmente na Tecniplas Ind?stria e Com?rcio LTDA. na forma de placa, e o processo de fabrica??o utilizado foi ? lamina??o manual (Hand Lay up). A partir da placa foram preparados corpos de prova para ensaios de densidade volum?trica, absor??o de umidade, tra??o uniaxial nos estados seco e ?mido, e ensaio de flex?o, al?m de estudos sobre o comportamento da fratura gerada nos ensaios mec?nicos por meio do MEV. Todos os ensaios foram feitos de modo a achar as aplica??es mais vi?veis ao comp?sito hibrido fabricado. Nos ensaios de tra??o e flex?o foram analisadas as propriedades de tens?o ?ltima, m?dulo de elasticidade e deforma??o. A partir dos resultados observa-se que o percentual de umidade absorvido foi de 3,03%, um valor razoavelmente alto, dado o intervalo de tempo que ocorreu esta absor??o. A presen?a de umidade no ensaio de tra??o significou uma queda de 19,77% da resist?ncia ?ltima, e 5,26% no m?dulo de elasticidade. Para os ensaios de flex?o obteve-se o valor m?dio de 69,13 MPa de resist?ncia ? flex?o. Os resultados apontam a aplica??o do comp?sito hibrido estudado em estruturas leves, ambientes internos, onde exijam solicita??es de tra??o de baixo/m?dio desempenho, e onde envolvem solicita??es de flex?o. / This work aims to manufacture and characterize a hybrid plastic composite with the matrix isophthalic polyester resin base and having as reinforcing glass fiber and the dry endocarp of coconut (Coco nucifera Linn) in the form of particles as filler. The composite was made industrially in Tecniplas Industry and Trade LTDA. in the form of plate, and was manufactured process made by the manual lamination (Hand Lay Up). From the plate they were prepared test specimens for testing density, water absorption, uniaxial traction in dry and wet states, and testing of bending, as well as studies on the behavior of the generated fractures, macroscopic and microscopic, in mechanical tests through. All tests were performed in order to find the most viable applications the hybrid composite manufactured. The tensile and bending tests were analyzed last tensile properties, elasticity and deformation module. After the studies, it is observed that the percentage moisture absorbed was 3.03%. The presence of moisture in the tensile test meant a decrease of 19.77% from last stand, and 5.26% in the elastic modulus. For bending tests gave an average value of 69.13 MPa flexural strength. The results show the application of hybrid composite studied in lightweight structures, indoors, which require low / medium performance traction demands, and which involve flexural requests.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-06T19:38:09Z No. of bitstreams: 1 JoseRibeiroDeSouzaFilho_TESE.pdf: 4358122 bytes, checksum: 4f7e4f1461183c83e90986ad9b9ed75b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-07T17:36:23Z (GMT) No. of bitstreams: 1 JoseRibeiroDeSouzaFilho_TESE.pdf: 4358122 bytes, checksum: 4f7e4f1461183c83e90986ad9b9ed75b (MD5) / Made available in DSpace on 2016-07-07T17:36:23Z (GMT). No. of bitstreams: 1 JoseRibeiroDeSouzaFilho_TESE.pdf: 4358122 bytes, checksum: 4f7e4f1461183c83e90986ad9b9ed75b (MD5) Previous issue date: 2015-12-18 / Com o surgimento de novas tecnologias, tem crescido a necessidade de utiliza??o de novos materiais, e com isso tem se intensificado pesquisas sobre a obten??o e utiliza??o de materiais provenientes de fontes renov?veis, seja para reduzir os custos de produ??o e/ou impacto ambiental. Nesse contexto, verificou-se que a bainha da palha do coqueiro pode ser aproveitada como mat?ria-prima para a produ??o de um comp?sito que pode ser utilizado como isolante t?rmico e ac?stico. Depois de selecionadas as bainhas do coqueiro foram submetidas a tratamento com solu??o aquosa com 2% de hidr?xido de s?dio (NaOH). O comp?sito mencionado foi produzido com bainha do coqueiro e l?tex natural, com percentuais de bainha nas propor??es 15%, 25% e 35% do volume total do composto. As propriedades f?sico-mec?nicas avaliadas foram: Densidade, Absor??o de ?gua, Teor de Umidade, Microscopia Eletr?nica, Dureza Shore e Resist?ncia ? Tra??o. Al?m dos par?metros j? mencionados, foram determinadas a Condutividade T?rmica, Difusividade T?rmica, Resistividade T?rmica, Calor Espec?fico, Inflamabilidade, bem como a Isola??o Ac?stica, proporcionada pelo comp?sito em estudo. As an?lises foram fundamentadas em normas ABNT, ASTM e UL. Diante dos resultados obtidos, pode-se concluir que o comp?sito produzido a partir da bainha do coqueiro pode ser utilizado como isolamento t?rmico e ac?stico. Com isso, d?-se um fim mais nobre a este material, que na maioria das vezes ? queimado ou descartado inadequadamente no meio ambiente. / With the emergence of new technologies, has grown the need to use new materials, and this has intensified research on the collection and use of materials from renewable sources, is to reduce production costs and / or environmental impact. In this context, it was found that the sheath coconut straw, can be utilized as raw material for the production of a eco-composite that can be used as a thermal and acoustic insulator. After selected from the coconut sheaths were subjected to treatment with aqueous 2 % sodium hydroxide (NaOH). The composite study was produced with the sheath and coconut natural latex, with coconut sheath percentage in the proportions 15%, 25% and 35% of the total compound volume. Physical, thermal and acoustic properties of the composites were analyzed in order to obtain data on the use of viability as thermoacoustic insulation. The CP15 composites, CP25 and CP35 showed thermal conductivity 0.188 W/m.K, 0.155 W/m.K and 0.150 W/m.K, respectively. It can be applied as thermal insulation in hot systems to 200 ? C. The CP35 composite was more efficient as a thermal and acoustic insulation, providing 20% noise reduction, 31% and 34% for frequencies of 1 kHz, 2 kHz and 4 kHz, respectively. The analyzes were based on ABNT, ASTM, UL. Based on these results, it can be concluded that the eco-composite produced the hem of coconut can be used as thermal and acoustic insulation. Thus, it gives a more noble end to this material, which most often is burned or disposed of improperly in the environment.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-20T17:21:11Z No. of bitstreams: 1 AlvaroCesarPontesGalvao_TESE.pdf: 6716777 bytes, checksum: df8fe317e5a0a57cfab2282907650b26 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-22T12:13:19Z (GMT) No. of bitstreams: 1 AlvaroCesarPontesGalvao_TESE.pdf: 6716777 bytes, checksum: df8fe317e5a0a57cfab2282907650b26 (MD5) / Made available in DSpace on 2018-03-22T12:13:19Z (GMT). No. of bitstreams: 1 AlvaroCesarPontesGalvao_TESE.pdf: 6716777 bytes, checksum: df8fe317e5a0a57cfab2282907650b26 (MD5) Previous issue date: 2018-01-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A utiliza??o de uma espuma de poliuretano proveniente de uma fonte renov?vel, como ? o caso da espuma poliuretano de mamona e adi??o de cargas rejeitos t?o abundantes no Nordeste (scheelita e gr?s porcelanato), representaria uma redu??o do consumo de espuma de origem exaur?vel. Sendo assim, verifica-se a necessidade de estudos relativos ao desempenho termof?sico/mec?nico de comp?sitos desta espuma com rejeitos do beneficiamento da scheelita e do polimento do gr?s porcelanato para fins de isola??o t?rmica. Esta pesquisa objetivou desenvolver comp?sitos de poliuretano de mamona (PURM) com cargas de rejeitos de porcelanato (PRP) e scheelita (PRS) que possam ser utilizados como isolantes t?rmicos alternativos, visando ? redu??o de custos e consumo de mat?ria-prima, al?m de contribuir com o desenvolvimento sustent?vel dessas ind?strias. No estudo utilizou-se micropart?culas PRS e PRP para o desenvolvimento e caracteriza??o de comp?sitos de PURM. Estes comp?sitos foram caracterizados termofisicamente a partir de ensaios de condutividade t?rmica, calor espec?fico, difusividade t?rmica e termogravimetria. Propriedades como massa espec?fica, resist?ncia ? compress?o e dureza tamb?m foram analisadas nos comp?sitos PURM+PRS e PURM+ PRP. As estruturas celulares destes comp?sitos de PURM foram analisadas pelas t?cnicas de MEV (Microscopia Eletr?nica de Varredura) com microan?lise qu?mica EDS (Espectroscopia por Energia Dispersiva de Raios X). Verificou-se que os melhores comp?sitos com propriedades isolantes foram PURM+5PRP125 e PURM+5PRP300-600 por possu?rem menor condutividade t?rmica. O mesmo ocorreu para os comp?sitos de PURM+5PRS, tamb?m para ambos os tamanhos de part?culas (125 ?m e entre 300 a 600 ?m). Entretanto, comparando a efici?ncia de isola??o t?rmica baseada nos menores valores de condutividade t?rmica e maior calor espec?fico, tem-se o comp?sito PURM+5PRP125 como o que apresentou um comportamento t?rmico mais pr?ximo ao do PURM-Puro e cuja isola??o t?rmica foi maior que a dos demais comp?sitos de PURM e tamb?m dos isolantes t?rmicos comerciais (l? de rocha, l? de vidro, EPS, etc.). / The use of a polyurethane foam from a renewable source, as the case of the foam from the castor oil and addition of waste (scheelite and porcelain stoneware) plentiful in the northeast region of Brazil, would represent a reduction of consume in limited source foam. Due to this, it is verified the necessity of studies concerning to the thermophysical/mechanical performance of this foam composites with both the scheelite processing and polishing porcelain stoneware wastes for thermal insulation purposes. This research aimed to develop composites of rigid polyurethane foam from ricin oil (PURM) with stoneware porcelain (PRP) and scheelite (PRS) waste which could be used as thermal insulation, aiming the reduction of costs and raw material consume; furthermore, to contribute with the sustainable development of these industries. In this study were used PRS and PRP microparticles for confection and characterization of PURM composites. These composites were thermophysical characterized with tests of thermal conductivity, specific heat, thermal diffusivity and thermogravimetry. Material properties such as density, compressive strength and hardness were also analyzed in the PURM+PRS and PURM+PRP composites. The cellular structures of these PURM composites were analyzed by MEV (Scanning Electron Microscopy) with chemical microanalysis EDS (Energy Dispersive X-Ray Spectroscopy). It was verified that the best composites with insulating properties were PURM+5PRP125 and PURM+5PRP300-600 because they had a lower thermal conductivity than other PURM composites. The same occurred for the PURM+5PRS composites, also for both particle sizes (125 ?m and between 300 and 600 ?m). However, comparing the thermal insulation efficiency based on the lower values of thermal conductivity and higher specific heat, the PURM+5PRP125 composite was the one which presented the closest thermal behavior value to PURM-Pure, likewise exhibited higher thermal insulation than the other PURM composites and the commercially available thermal insulators (rock wool, glass wool, EPS, and others).

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-27T12:30:35Z No. of bitstreams: 1 FlavioAnselmoSilvaDeLima_TESE.pdf: 5034235 bytes, checksum: 5889588654d8773f78e4f287028fd71b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-30T14:46:40Z (GMT) No. of bitstreams: 1 FlavioAnselmoSilvaDeLima_TESE.pdf: 5034235 bytes, checksum: 5889588654d8773f78e4f287028fd71b (MD5) / Made available in DSpace on 2017-01-30T14:46:40Z (GMT). No. of bitstreams: 1 FlavioAnselmoSilvaDeLima_TESE.pdf: 5034235 bytes, checksum: 5889588654d8773f78e4f287028fd71b (MD5) Previous issue date: 2016-06-17 / A utiliza??o de materiais comp?sitos na constru??o civil tem sido linha de pesquisa nos maiores centros de pesquisas do Brasil e do mundo. Um dos fatores que justifica essa busca ? o d?ficit habitacional dos pa?ses subdesenvolvidos e em desenvolvimento. No Brasil esse d?ficit alcan?a mais de 5,4 milh?es de moradias, em torno de 12% dos domic?lios do pa?s. Esse trabalho apresenta um comp?sito que foi obtido a partir de materiais convencionalmente utilizados, cimento, gesso e areia; res?duos industriais gerados, o EPS, raspa de pneu e ?gua O ineditismo do trabalho est? no estudo de caracteriza??o combinada, t?rmica e mec?nica do comp?sito obtido. Estudou-se tamb?m a influ?ncia de tr?s tipos de recheio, colocados nos blocos (79cm X 28cm X 10cm) fabricados com o material comp?sito destinado ? edifica??o de resid?ncias populares. Foram estudadas quatro formula??es para o estudo combinado, determinando-se a mais vi?vel. Ser?o apresentados os processos de fabrica??o e montagem dos blocos produzidos para a constru??o de resid?ncias populares. Determinou-se o tipo de recheio, placas de EPS recicladas, latas de cervejas e refrigerantes reutilizadas e garrafas PETs de ?gua mineral de 500ml. Foi tamb?m realizado um estudo preliminar de conforto t?rmico com blocos fabricados com os recheios utilizados em um espa?o edificado em uma Escola P?blica de Natal, denominado Espa?o Ci?ncia. A resist?ncia mec?nica do comp?sito para todas as formula??es est? classificada como alvenaria de veda??o, abaixo 3,0 MPa. A resist?ncia t?rmica dos blocos foi comprovada pela diferen?a de temperatura m?xima entre as paredes interna e externa do c?modo edificado em torno 8,0 ?C e condutividade t?rmica praticamente igual a do tijolo de oito furos e inferior a dos blocos de concreto e tijolos maci?os, o que demonstrou a viabilidade de utiliza??o dos blocos produzidos para o fim proposto. Outras caracter?sticas importantes dos blocos produzidos ? o seu bom acabamento, n?o necessitando de reboco, o que diminui o custo de m?o de obra em um processo construtivo e o seu r?pido tempo de cura, pela utiliza??o do gesso. A formula??o mais vi?vel para o estudo combinado, t?rmico e mec?nico foi 1,0 C + 1,0 G + 1,0 EPS + 1,0 RP. Para a fabrica??o de blocos essa formula??o seria a mais vi?vel com e com recheio de placas de EPS. / The use of composite materials in construction has been a line of research quite investigated in Brazil and worldwide. One of the factors justifying this search is the housing deficit of underdeveloped and developing countries. In Brazil this deficit reaches more than 5.4 million homes, approximately 12% of all country households according to IBGE 2012. To contribute to the reduction of this housing deficit presents the study of four formulations of a composite that was obtained from materials conventionally used in construction (cement, gypsum and sand), together with residue of own construction (Styrofoam) tire scrapings and water in order to manufacture blocks with dimensions (79 cm x 28 cm x 10 cm) for building affordable housing using different types of fillings inside the block, such as cans, bottles of mineral water and EPS boards. Was built a room using blocks with the fillings mentioned above in a Public School Christmas and conducted temperature checks on these blocks. They were also performed mechanical, thermal and physical testing to characterize the best formulation. The mechanical strength of the composite for all formulations are classified as sealing masonry below 3.0 MPa. The thermal resistance of the blocks was confirmed by the maximum temperature difference between the inner and outer walls of the room built around 8.0 ? C and thermal conductivity nearly equal to the eight holes wall and bottom of the concrete blocks and solid bricks, which demonstrated the feasibility of using blocks made for the intended purpose.