Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-05-04T22:43:24Z No. of bitstreams: 1 EdilsonMarinhoSilvaJunior_DISSERT.pdf: 6513664 bytes, checksum: 740829bb11d8300fd197873698355261 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-05-04T22:53:06Z (GMT) No. of bitstreams: 1 EdilsonMarinhoSilvaJunior_DISSERT.pdf: 6513664 bytes, checksum: 740829bb11d8300fd197873698355261 (MD5) / Made available in DSpace on 2017-05-04T22:53:07Z (GMT). No. of bitstreams: 1 EdilsonMarinhoSilvaJunior_DISSERT.pdf: 6513664 bytes, checksum: 740829bb11d8300fd197873698355261 (MD5) Previous issue date: 2014-08-04 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A crescente necessidade do mercado competitivo industrial de determinar e prever com maior confiabilidade e seguran?a mecanismos de falhas em sistema mec?nicos din?micos, como, por exemplo, os motores a combust?o interna, faz com que as grandes ind?strias invistam recursos em medidas preventivas e preditivas, a fim de alcan?ar uma maior produtividade industrial e diminuir custos no relevante aos crit?rios de parada das m?quinas, aliado ao mesmo tempo com a necessidade de buscar novas formas de combust?veis alternativos, atrav?s do uso combinado de fontes f?sseis de energias, de modo a preservar o tempo ?til do equipamento e buscar uma economia sustent?vel. A presente disserta??o consiste portanto em comparar e descrever par?metros tribol?gicos e de desempenho dos efeitos da utiliza??o em motores DASH 9 7FDL16-EFI, de locomotivas ferrovi?rias abastecidas com a mistura Diesel/GNL nas propor??es 70%/30%, em compara??o com um mesmo motor abastecido apenas por combust?vel Diesel. Para isso, faz-se o uso da mensura??o de componentes mec?nicos (cilindros, an?is de segmento e v?lvulas) por meio da utiliza??o de an?lises dimensionais, an?lise diametral nos cilindros, folga, espessura e abertura dos an?is de segmento e abertura de v?lvulas, somados com a an?lise dos seus fen?menos f?sicos, press?o, temperatura, vibra??o, par?metros dos motores, emiss?o, lubrificante e n?vel de press?o sonora, relacionando os dois m?todos de an?lise, matem?tica e estatisticamente, comparando os motores e relatando o desempenho do uso do motor bicombust?vel, Diesel/GNL (70%/30%), no ?mbito da vida do sistema din?mico submetido a 1050 horas de ensaio em plena carga. Observou-se, dessa forma, que motores abastecidos com a mistura Diesel/GNL, nas propor??es 70%/30% evidenciou um desgaste menor que o previsto em literatura e em alguns componentes quando comparados com o outro motor abastecido apenas por Diesel. / The growing need of the industrial competitive market to determine and predict with greater safety and reliability failure mechanisms in dynamic mechanical system, for example, internal combustion engines, makes the big industries to invest resources in preventive and predictive measures, the achieve greater industrial productivity and reduce costs in the relevant criteria for stopping the machines together at the same time with the need to seek new forms of alternative fuels, through the combined use of fossil energy sources, in order to preserve the time working equipment and seek a sustainable economy. The present work is therefore to compare and describe tribological performance and the effects of use in DASH-9 7FDL16 EFI engines, railway locomotives supplied with diesel / GNL mixture in the proportion 70% / 30% parameters, compared with a same motor fueled by diesel fuel only. For this, use is made of the measurement of mechanical components (cylinders, piston rings and valves) by using dimensional analysis, analysis in diametral cylinders off, thickness and opening of the piston rings and valve timing, added with the analysis of its physical phenomena, pressure, temperature, vibration, motor parameters, emission, lubricant and sound pressure level, linking the two methods of analysis, mathematical and statistically comparing the engines and reporting the performance of using dual-fuel engine , diesel / GNL (70% / 30%), within the life of the dynamic system subjected to 1050 hours of testing at full load. It has been observed thereby that engines fueled with diesel / LNG mixture in the proportion 70% / 30% showed less wear than expected in the literature and some components compared with the other engine fueled by diesel only.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-06-02T19:54:04Z No. of bitstreams: 1 ClaraCarolineDeAraujoAzevedo_DISSERT.pdf: 1622332 bytes, checksum: a226e1d5a2312a2d2809f6bf010fd2bc (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-06-05T23:37:12Z (GMT) No. of bitstreams: 1 ClaraCarolineDeAraujoAzevedo_DISSERT.pdf: 1622332 bytes, checksum: a226e1d5a2312a2d2809f6bf010fd2bc (MD5) / Made available in DSpace on 2017-06-05T23:37:12Z (GMT). No. of bitstreams: 1 ClaraCarolineDeAraujoAzevedo_DISSERT.pdf: 1622332 bytes, checksum: a226e1d5a2312a2d2809f6bf010fd2bc (MD5) Previous issue date: 2017-02-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Foi desenvolvido um comp?sito a base de gesso e vermiculita destinado ao uso como material de isola??o t?rmica em elementos construtivos. Na composi??o da mistura, considerou-se a adi??o de vermiculita em substitui??o ao gesso nas seguintes propor??es: 0 % (?padr?o?), 5 %, 10 %, 15 % e 20 %. Duas raz?es de ?gua / gesso (A/G) foram consideradas na produ??o das misturas: 0,45 e 0,8. Foram fabricados corpos de prova cil?ndricos para determina??o das propriedades t?rmicas das misturas. Foram medidos os seguintes par?metros: condutividade, resistividade, difusividade e capacidade calor?fica volum?trica. Para estudo do desempenho t?rmico, foram produzidos corpos de prova com formato de placa plana. Cada placa foi fixada na parte superior de uma c?mara de testes termicamente isolada. Termopares foram instalados nas faces das placas, no interior e na base da c?mara. Em seguida, foram conectados a um sistema de aquisi??o de dados ligado a um computador. As c?maras, com cada composi??o de mistura, foram montadas sob uma fonte de radia??o t?rmica artificial situada no interior de uma sala climatizada. A partir dos resultados dos ensaios, foram constru?dos gr?ficos para compara??o dos par?metros t?rmicos e de desempenho t?rmico de cada composi??o. Com base nos resultados dos ensaios, determinou-se que, em rela??o ao gesso comum, o comp?sito desenvolvido apresentou: menor massa espec?fica, redu??o da condutividade t?rmica e aumento da resistividade t?rmica em fun??o do aumento do teor de vermiculita adicionado ? mistura e maior capacidade de isola??o t?rmica. A combina??o dessas caracter?sticas tornam o comp?sito desenvolvido pass?vel de uso como material para produ??o de elementos construtivos que proporcionem redu??o da carga t?rmica no interior das edifica??es devido ? radia??o solar incidentes nos fechamentos opacos e, consequentemente, melhor conserva??o de energia. / A composite based on gypsum and vermiculite was developed to be used as thermal insulation material in building elements. In the composition of the mixture, the addition of vermiculite in substitution of gypsum in the following proportions was considered: 0% ("standard"), 5%, 10%, 15% and 20%. Two water / gypsum (A / G) ratios were considered in the production of the mixtures: 0.45 and 0.80. Cylindrical test proof body were fabricated to determine the thermal properties of the mixtures. The thermal properties were determined using the KD - 2 Pro meter manufactured by Decagon Devices Inc. The following parameters were measured: conductivity, resistivity, diffusivity and volumetric heat capacity. To study the thermal performance, flat bodies were produced with flat plate format. Each plate was attached to the top of a thermally insulated test chamber. Thermocouples were installed on the faces of the plates, inside and at the base of the chamber. They were then connected to a data acquisition system connected to a computer. The chambers, with each mixing composition, were mounted under a source of artificial thermal radiation located inside a heated room. From the results of the tests, graphs were constructed to compare the thermal parameters and thermal performance of each composition. Based on the results of the tests, it was determined that, in relation to the common gypsum, the composite developed showed: lower specific mass, reduction of thermal conductivity and increase of thermal resistivity as a function of the increase of vermiculite content added to the mixture and greater capacity Thermal insulation. The combination of these characteristics makes the composite developed usable as a material for the production of constructive elements that provide reduction of the thermal load inside the buildings due to the solar radiation incident on the opaque closures and, consequently, better conservation of energy.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-06-13T19:15:42Z No. of bitstreams: 1 AlcioneOlintoGalvao_TESE.pdf: 2924664 bytes, checksum: f8011e637681ba38a8a5c55b07dc7de6 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-06-14T21:19:34Z (GMT) No. of bitstreams: 1 AlcioneOlintoGalvao_TESE.pdf: 2924664 bytes, checksum: f8011e637681ba38a8a5c55b07dc7de6 (MD5) / Made available in DSpace on 2017-06-14T21:19:35Z (GMT). No. of bitstreams: 1 AlcioneOlintoGalvao_TESE.pdf: 2924664 bytes, checksum: f8011e637681ba38a8a5c55b07dc7de6 (MD5) Previous issue date: 2017-01-20 / A remo??o de metais t?xicos das ?guas residuais ? de grande interesse no estudo da polui??o da ?gua. Entre os v?rios metais conhecidos por serem altamente t?xico destaca-se o c?dmio, que ? considerado como uma das subst?ncias mais perigosas podendo causar s?rios danos aos rins e ossos. O processo de adsor??o vem sendo utilizado como um m?todo eficaz para a remo??o de ?ons met?licos. Uma alternativa para utiliza??o de adsorventes em forma de p? ? sua utiliza??o em conjunto com outros materiais. Com esse intuito, o presente estudo teve como objetivo desenvolver blendas polim?ricas (PVA/Amido), tendo a hidroxiapatita (HAP) e o biovidro (BV) dispersos no meio para a remo??o dos ?ons de c?dmio. Realizou-se, inicialmente, a caracteriza??o dos p?s e das blendas polim?ricas por diferentes t?cnicas: An?lise Termogravim?trica (TGA), Espectroscopia de Infravermelho Transformada de Fourier (FTIR), Difra??o de Raios X (DRX), Espectrometria de fluoresc?ncia de raios-X (FRX), Microscopia Eletr?nica de Varredura (MEV), Microscopia de For?a At?mica (AFM), Determina??o do Potencial Zeta. Foram realizados os ensaios de adsor??o a fim de estudar a cin?tica e o equil?brio na adsor??o dos ?ons met?licos, bem como um planejamento fatorial atrav?s do software Design Expert. As an?lises de caracteriza??o mostram que os materiais adsorventes s?o adequados para utiliza??o na remo??o de metais pesados. Os dados cin?ticos mostraram melhor correla??o com a equa??o de velocidade de pseudo-segunda ordem e os pontos experimentais se ajustaram ao modelo da isot?rmica de Freundlich. O planejamento experimental apresentou um coeficiente de determina??o (R?) de 0,9826 e 0,9991 para as blendas polim?ricas PVA/Amido/HAP e PVA/Amido/BV, respectivamente, com um n?vel de confian?a de 95%. Com isso, a adsor??o do c?dmio pelas blendas polim?ricas com HAP e BV em solu??o aquosa mostraram-se eficientes, tornando o processo vi?vel para a remo??o de metais pesados. / The removal of toxic metals from wastewater is of great interest in the study of water pollution. Among the various metals known to be highly toxic is cadmium, which is considered one of the most dangerous substances and can cause serious damage to the kidneys and bones. The adsorption process has been used as an effective method for the removal of metallic ions. An alternative to the use of adsorbents in powder form is their use in conjunction with other materials. The aim of the present study was to develop polymer blends (PVA/Starch), with hydroxyapatite (HAP) and bioglass (BV) dispersed in the medium for the removal of cadmium ions. The characterization of the powders and the polymer blends was carried out by different techniques: Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray Fluorescence Spectrometry FRX), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Determination of Zeta Potential. The adsorption tests were carried out in order to study the kinetics and the equilibrium in the adsorption of the metallic ions, as well as a factorial planning through the software Design Expert. Characterization analyzes show that the adsorbent materials are suitable for use in the removal of heavy metals. The kinetic data showed better correlation with the pseudo-second order velocity equation and the experimental points conformed to the Freundlich isothermal model. The experimental design presented a coefficient of determination (R?) of 0.9826 and 0.9999 for the polymer blends PVA/Starch/HAP and PVA/Starch/BV, respectively, with a confidence level of 95%. Thus, the adsorption of the cadmium by the polymer blends with HAP and BV in aqueous solution proved to be efficient, making the process viable for the removal of heavy metals.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-07-03T13:37:23Z No. of bitstreams: 1 LeandroLuizDaSilvaPereira_DISSERT.pdf: 10051425 bytes, checksum: 2c83b499adde5859560e54458c90cb2c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-07-07T12:37:13Z (GMT) No. of bitstreams: 1 LeandroLuizDaSilvaPereira_DISSERT.pdf: 10051425 bytes, checksum: 2c83b499adde5859560e54458c90cb2c (MD5) / Made available in DSpace on 2017-07-07T12:37:13Z (GMT). No. of bitstreams: 1 LeandroLuizDaSilvaPereira_DISSERT.pdf: 10051425 bytes, checksum: 2c83b499adde5859560e54458c90cb2c (MD5) Previous issue date: 2016-12-29 / Evitar falhas ? uma medida extremamente necess?ria quando se gerencia sistemas de produ??o e distribui??o de ?gua com 95% das redes pressurizadas diretamente por po?os. Baseado nas frequentes faltas de ?gua em 2015, registradas pela CAERN na Unidade de Opera??o e Manuten??o de ?guas de Parnamirim (UNAP), destacam-se as avarias causadas por sobreaquecimento e outros danos de natureza mec?nica e el?trica que levam a falhas nas instala??es de motobombas submersas. Nesse escopo, este trabalho foi dedicado a realizar um estudo de caso sobre as instala??es de quatro motobombas dos po?os PC, PD, PS e PI, com diferentes acionamentos el?tricos, utilizando a proposta da Roda de Falhas (Failure Wheel) numa an?lise preditiva el?trica e termogr?fica, para inferir qualitativamente sobre o n?vel de confiabilidade e custo de manuten??o na concession?ria de abastecimento d??gua. Para subsidiar as an?lises foram inspecionados itens importantes das referidas instala??es, observando suas rela??es de conformidade com as especifica??es das motobombas, onde foram efetuadas medi??es de par?metros el?tricos e t?rmicos de opera??o, incluindo vari?veis de estresse para auxiliar no diagn?stico e estimar os desempenhos dessas m?quinas. A an?lise foi conduzida por ficha de inspe??o de par?metros operacionais, checklist e pela Roda de Falhas em discuss?o, que permitiram diagn?sticos sobre os dados das inspe??es e do hist?rico de falhas recorrentes. Nesse sentido, a aplica??o da Roda de Falhas se deu com a adapta??o de um modelo para as motobombas submersas, identificando os principais mecanismos de danos associados ?s causas gerais de falhas, que demonstrou viabilidade em rotinas de manuten??o baseada na condi??o para an?lise detectiva-preditiva de falhas em curso nos equipamentos. Comparando o consumo espec?fico de energia entre as motobombas, a PI, com acionamento por inversor de frequ?ncia, obteve melhor rendimento, oferecendo maior efici?ncia energ?tica durante a capta??o d??gua entre julho de 2015 e julho de 2016. A mesma demonstrou risco reduzido de falhas t?picas de motobombas dentre os equipamentos, tendo em vista o menor n?vel t?rmico em opera??o apresentado nas termografias, e o menor estresse causado devido ?s caracter?sticas da chave de partida. Conclui-se, portanto, que seu n?vel de confiabilidade foi o maior, seguido da PS, PC e PD. As vantagens da aplica??o sistem?tica da proposta, aliada a uma pol?tica de manuten??o planejada, apontam para a redu??o de intercorr?ncias por falhas e perdas de produ??o, e com isso, permitem diminuir trocas prematuras de equipamentos e custos com manuten??o e energia el?trica. Como resultado da pesquisa obteve-se uma metodologia de acompanhamento preditivo, visando a??es de manuten??o antes da falha catastr?fica sobre itens em percurso de danos. / Avoiding failures is an extremely necessary measure when managing water production and distribution systems with 95% of networks pressurized directly by wells. Based on the frequent water shortages in 2015, registered by CAERN at the Parnamirim Water Operation and Maintenance Unit (UNAP), the most notable are the damages caused by overheating and other mechanical and electrical damages that lead to failures in the motor pump Submerged. In this scope, this work was carried out to carry out a case study on the installations of four well pumps PC, PD, PS and PI, with different electric drives, using the Failure wheel proposal in an electric predictive analysis And thermographic, to qualitatively infer about the level of reliability and cost of maintenance in the water supply concessionaire. In order to subsidize the analyzes, important items of the aforementioned facilities were inspected, observing their relations of conformity with the specifications of the pumps, where electrical and thermal parameters of operation were carried out, including stress variables to aid in the diagnosis and to estimate the performances of these machines. The analysis was carried out by a checklist of operational parameters, checklist and by Failure Wheel in discussion, which allowed for diagnoses on inspection data and the history of recurring faults. In this sense, the application of the Failure Wheel occurred with the adaptation of a model for the submersible pumps, identifying the main damage mechanisms associated to the general causes of failures, which demonstrated viability in maintenance routines based on the condition for detective-predictive analysis of faults in the equipment. Comparing the specific energy consumption between the pumps, the PI, with drive by frequency inverter, obtained better efficiency, offering greater energy efficiency during the water harvest between July 2015 and July 2016. It showed a reduced risk of failure Typical of motor pumps, among the equipment, considering the lower thermal level in operation presented in thermographs, and the lower stress caused due to the characteristics of the starter. It was concluded, therefore, that its reliability level was the highest, followed by PS, PC and PD. The advantages of the systematic application of the proposal, coupled with a planned maintenance policy, point to the reduction of intercurrences due to failures and losses of production, and with this, allow to reduce premature equipment changes and costs with maintenance and electric energy. As a result of the research, a methodology of predictive monitoring was obtained, aiming at maintenance actions before the catastrophic failure on items in the course of damages.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-01T12:12:37Z No. of bitstreams: 1 FilipiMarquesDeSouza_DISSERT.pdf: 2397321 bytes, checksum: 6de0b5d432140e6035f286ca4eaee007 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-03T19:43:58Z (GMT) No. of bitstreams: 1 FilipiMarquesDeSouza_DISSERT.pdf: 2397321 bytes, checksum: 6de0b5d432140e6035f286ca4eaee007 (MD5) / Made available in DSpace on 2017-08-03T19:43:58Z (GMT). No. of bitstreams: 1 FilipiMarquesDeSouza_DISSERT.pdf: 2397321 bytes, checksum: 6de0b5d432140e6035f286ca4eaee007 (MD5) Previous issue date: 2017-03-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Os crescentes desenvolvimentos tecnol?gicos e econ?micos convergem para a necessidade de cria??o de materiais cada vez mais eficientes, os quais buscam unir alto desempenho e baixo custo. Os comp?sitos surgem como solu??o para substitui??o de materiais convencionais, por serem desenvolvidos para aplica??es especificas, podendo apresentar caracter?sticas desejadas. Os tecidos h?bridos aplicados em comp?sitos fibrosos, se projetados adequadamente, possibilitam uma melhoria ainda maior no rendimento, j? que, diferentemente dos tecidos convencionais, os tecidos h?bridos combinam fibras diferentes com alinhamento dependente do tipo de solicita??o de carga, podendo obter um material mais eficiente. Neste trabalho, foram realizadas an?lises com o intuito de estudar o comportamento de uma l?mina de comp?sito refor?ado por tecido h?brido bidirecional vidro/carbono em presen?a de descontinuidades geom?tricas. Para a realiza??o desse estudo o comp?sito foi fabricado a partir do processo de moldagem manual (hand-lay up). A partir dos ensaios realizados, de acordo com as normas da ASTM, obtiveram-se as caracter?sticas e propriedades do material (Percentual m?ssico e volum?trico de fibras, gr?ficos de tens?o x deforma??o, resist?ncia ?ltima e m?dulo de elasticidade). Foram analisadas configura??es com as fibras alinhadas nas dire??es principais (0? e 90?) e em ?ngulo (30?, 45? e 60?). A l?mina obteve um percentual m?ssico total de fibras de 38,98%, sendo 19,49% de fibra de vidro e 19,49% de fibra de carbono. J? para o percentual volum?trico obtiveram-se os seguintes resultados: 10,91% de fibra de vidro e 14,88% de fibra de carbono. A partir dos resultados obtidos nos ensaios de tra??o p?de-se observar que os materiais com fibras em ?ngulo apresentam resist?ncia inferior aos com alinhamento na dire??o principal e ao mesmo tempo apresentaram maiores alongamentos. A resist?ncia residual apresentou resultados semelhantes tendo valores em torno de 0,774, exceto para o material com angula??o de 30?, o qual apresentou um valor de 0,676. Diante dos resultados encontrados, torna-se evidente que a descontinuidade geom?trica ? um fator relevante na resist?ncia deste comp?sito e deve ser considerada. / The technological and economic development growing converge to the necessity of create increasingly efficient materials, which seek to combine high performance and low cost. The composites appear as solution to substitute conventional materials, because they are developed for specific applications and may have desired characteristics. Hybrid fabrics applied to fibrous composites, if adequately designed, allow an even greater improvement in efficiency, since, unlike conventional fabrics, these combine different fibers with different load-dependent alignment and can obtain a more efficient material. In this work, analyzes were carried out with the aim of studying the behavior of a composite lamina reinforced by bi - directional (glass/carbon) hybrid fabric in presence of geometric discontinuities. In order to carry out this study, the composite material was fabricated from the manual molding process (hand-lay up). From the tests performed, according to ASTM standards, the characteristics and properties of the material were obtained (mass and volume percentages of fibers, stressstrain curve, ultimate strength and modulus of elasticity). Configurations were made with fibers aligned in the main directions (0? and 90?) and at angles (30?, 45? and 60?). The composite lamina had a total mass percentage of fibers of 38.98%, being 19.49% of glass fiber and 19.49% of carbon fiber. For the volumetric percentage, the following results were obtained: 10.91% of glass fiber and 14.88% of carbon fiber. From the results obtained in the stress tests it was noted that the materials with angled fibers have lower resistance than those with alignment in the main direction and at the same time they presented greater stretches. The residual strength presented similar results having values around 0.774, except for the material with 30? angulations', which presented a value of 0.676. Considering the found results, it is evident that the geometric discontinuity is a relevant factor in the strength of this composite and should be considered.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-10T11:35:30Z No. of bitstreams: 1 AnaClaudiaDeMeloCaldasBatista_TESE.pdf: 6455968 bytes, checksum: e236bd6847574ecdc738c08d4eb6a4fb (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-10T16:05:11Z (GMT) No. of bitstreams: 1 AnaClaudiaDeMeloCaldasBatista_TESE.pdf: 6455968 bytes, checksum: e236bd6847574ecdc738c08d4eb6a4fb (MD5) / Made available in DSpace on 2017-08-10T16:05:11Z (GMT). No. of bitstreams: 1 AnaClaudiaDeMeloCaldasBatista_TESE.pdf: 6455968 bytes, checksum: e236bd6847574ecdc738c08d4eb6a4fb (MD5) Previous issue date: 2017-06-12 / Os tecidos h?bridos a base de fibras sint?ticas v?m sendo desenvolvidos pelo setor industrial como nova alternativa de refor?o para comp?sitos polim?ricos. Neste sentido, surge a necessidade do conhecimento das caracter?sticas mec?nicas desses comp?sitos polim?ricos com tecidos h?bridos, que at? o presente momento foram pouco estudados. Em determinadas condi??es de projetos, tr?s caracter?sticas s?o significativas: anisotropia, presen?a de descontinuidades geom?tricas e forma de hibridiza??o. Esta tese busca contemplar todas essas influ?ncias com o estudo de dois laminados comp?sitos, utilizando dois tecidos: o tecido h?brido de fibras de Carbono/Vidro e o tecido h?brido de fibras de Carbono/Aramida, ambos tendo como matriz a resina ep?xi ?ster Vin?lica. Para obten??o dos laminados foi utilizado o processo de fabrica??o de lamina??o manual (Hand-lay-up). Para o estudo proposto foram realizados os ensaios de tra??o uniaxial nos corpos de provas de forma que todos os diferentes tipos de fibras tivessem sua orienta??o coincidente com a dire??o da carga aplicada, al?m da orienta??o das fibras a ?45? com o objetivo de conhecer o comportamento ao cisalhamento para ambos os laminados. Os ensaios foram realizados, tanto para a condi??o original (sem furo) quanto para a condi??o com a descontinuidade geom?trica (caracterizada como um furo central, que para a orienta??o de fibra de melhor desempenho mec?nico teve seu di?metro vari?vel). Estudos das propriedades de resist?ncia ?ltima, rigidez e caracter?sticas da fratura mec?nica (macrosc?pica e microsc?pica) foram desenvolvidos. Para influ?ncia da rela??o w/D (largura do CP/di?metro do furo) foi realizado um estudo anal?tico tendo como base a avalia??o do fen?meno da concentra??o de tens?o a partir dos crit?rios de falhas: Crit?rio da Tens?o Pontual (Point Stress Criterion -PSC) e Crit?rio da Tens?o M?dia (Average Stress Criterion - ASC), assim como um estudo num?rico utilizando o M?todo de Elementos Finitos. Nesses estudos o objetivo central foi ? determina??o do fator de concentra??o de tens?o (K) dos materiais propostos, usando tanto a influ?ncia dos m?dulos el?sticos quanto unicamente dos par?metros geom?tricos. Os estudos mostraram que o comportamento mec?nico e caracter?stica da fratura foram fortemente influenciados pela anisotropia e hibridiza??o e a descontinuidade geom?trica. Os modelos anal?ticos e num?ricos obtiveram resultados em concord?ncia com os encontrados na literatura. Palavras chaves: Tecidos h?bridos, descontinuidade geom?trica, anisotropia, hibridiza??o. / Hybrid synthetic fiber-based fabrics have been developed by the industrial sector as a new reinforcement alternative for polymer composites. In this respect, there is a need to know the mechanical characteristics of these hybrid polymer composite fabrics, which have been little studied to date. Under project conditions, three characteristics are significant: anisotropy, geometric discontinuities and type of hybridization. This thesis aims to investigate all of these influences by studying two composite laminates, using two fabrics: a hybrid carbon/glass fiber fabric and a hybrid carbon/aramid fiber fabric, both with epoxy vinyl ester resin as matrix. The manufacturing process used was hand lay-up to obtain the laminates. Uniaxial tensile tests were conducted on test specimens so that all the different types of fibers were oriented in the direction of the applied load, in addition to fiber orientation at ?45? in order to determine the shear behavior of the laminates. The tests were carried out in both the original condition (without hole) and with geometric discontinuity (characterized as a central hole, whose diameter was variable for orientation of high mechanic performance fiber). A number of studies on ultimate strength and fracture mechanics characteristics (macroscopic and microscopic) have been conducted. To determine the influence of the w/D ratio (width of test specimen/diameter of the hole), an analytical study was performed based on stress concentration using Point Stress Criterion (PSC) and Average Stress Criterion (ASC) failure theories, as well as a numerical study using the Finite Elements Method. In these studies, the primary objective is to determine the stress concentration factor (K) of the proposed materials, using both the influence of elastic modulus and geometric parameters. The studies showed that mechanical behavior and fracture characteristics were strongly influenced by anisotropy, hybridization and geometric discontinuity. The analytical and numerical models obtained results showing good agreement with those reported in the literature.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-10T11:35:31Z No. of bitstreams: 1 RobertoKleciusMendoncaFernandes_TESE.pdf: 9615422 bytes, checksum: cd708447bea2bf643fce86924f5bbab0 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-11T10:55:04Z (GMT) No. of bitstreams: 1 RobertoKleciusMendoncaFernandes_TESE.pdf: 9615422 bytes, checksum: cd708447bea2bf643fce86924f5bbab0 (MD5) / Made available in DSpace on 2017-08-11T10:55:04Z (GMT). No. of bitstreams: 1 RobertoKleciusMendoncaFernandes_TESE.pdf: 9615422 bytes, checksum: cd708447bea2bf643fce86924f5bbab0 (MD5) Previous issue date: 2017-05-15 / O mancal seco ? um elemento estrutural presente na maioria dos sistemas mec?nicos das ind?strias dos setores eletrodom?sticos, agropecu?rios, aeroespacial, aeron?utico e automotivo. Este trabalho d? continuidade a uma linha de pesquisa iniciada no Grupo de Estudos de Tribologia e Integridade Estrutural (GET) da Universidade Federal do Rio Grande do Norte (UFRN) e tem o objetivo de investigar tribologicamente comp?sitos polim?ricos com matriz de politetrafluoretileno (PTFE) e carga de rejeito de scheelita para aplica??o em mancais secos, visando reduzir custo e aumentar a vida em servi?o destes elementos. O rejeito de scheelita, origin?rio da extra??o da scheelita utilizada para produ??o do tungst?nio, ? um res?duo mineral composto de ?xidos, como os de sil?cio, c?lcio, alum?nio, ferro, magn?sio, tungst?nio, dentre outros. O rejeito de scheelita foi caracterizado na condi??o como adquirido, atrav?s de an?lises de MEV e EDS, e peneirado para tamanho de part?cula inferior a 45 ?m. O PTFE foi analisado por DRX. PTFE e rejeito de scheelita foram misturados mecanicamente, moldados por compress?o a quente, num molde projetado envolto por uma resist?ncia el?trica, atrav?s de uma prensa hidr?ulica. Investigou-se o desempenho tribol?gico dos comp?sitos submetidos a cargas (1) em movimento linear alternado (reciprocating) e (2) com indenta??es repetidas. As superf?cies novas e ensaiadas foram analisadas por Microscopia de For?a At?mica (AFM) no que concerne aos par?metros de rugosidade peri?dica e n?o peri?dica. Verificou-se que a varia??o no teor de rejeito de scheelita e a frequ?ncia do movimento alternado influenciaram no desempenho tribol?gico e na resist?ncia do comp?sito, relacionados ao coeficiente de atrito, ? rugosidade, ao desgaste e ? indenta??o. Os comp?sitos polim?ricos desenvolvidos e ensaiados demonstraram se constituir em novos materiais adequados para aplica??o de mancais secos, notadamente o comp?sito com 80% de PTFE e 20% de rejeito de scheelita que, mostrando-se como de melhor desempenho tribol?gico, apresenta-se como uma alternativa vi?vel e de custo mais baixo que o PTFE puro. / Dry rubbing journal bearing is a structural part that is present in the most of mechanical systems of industries from home appliances, agricultural, aerospace, aeronautic and automotive sectors. This work gives continuity to a research started in Group of Studies in Tribology and Structural Integrity (GET) at Federal University of Rio Grande do Norte (UFRN) and has objective to investigate, tribologically, a scheelite tailings- filled PTFE composites to dry rubbing journal bearings application, to reduce cost and extend life service of this parts. The tailing of scheelite, obtained from scheelite mining to produce tungsten, is a mineral spoilage composed of oxides, as a silicon oxides, calcium, aluminum, iron, magnesium, tungsten and others. The tailing of scheelite was analyzed as acquired through SEM and EDS analysis, and sieved to get a particle size less than 45 ?m. PTFE was analyzed through XRD. PTFE and scheelite tailings was mechanically mixed, hot compression molding in a designed mold involved by a electrical resistance and compressed by a hydraulic press. It was investigated tribological performance of composites subject to loads (1) in reciprocating movement and (2) repeated indentations. The new and tested surfaces were analyzed through Atomic Force Microscope (AFM) to collect periodic and non periodic roughness parameters. It was verified that scheelite tailing content and frequency of reciprocating influenced tribological performance and strength of composites, related to coefficient of friction, roughness, wear and indentation. The developed and tested polymeric composites showed to constitute a new materials suitable to dry rubbing journal bearings applications, notably 80% of PTFE and 20% scheelite tailing composite content that was the best tribological performance composite and being introduced as a viable alternative and lower cost than pure PTFE.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-09-04T21:06:50Z No. of bitstreams: 1 ArturHenriqueSouzaSaldanha_DISSERT.pdf: 2798754 bytes, checksum: 3d0f4758fb9c195e823f40a6600942b8 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-09-06T22:40:36Z (GMT) No. of bitstreams: 1 ArturHenriqueSouzaSaldanha_DISSERT.pdf: 2798754 bytes, checksum: 3d0f4758fb9c195e823f40a6600942b8 (MD5) / Made available in DSpace on 2017-09-06T22:40:36Z (GMT). No. of bitstreams: 1 ArturHenriqueSouzaSaldanha_DISSERT.pdf: 2798754 bytes, checksum: 3d0f4758fb9c195e823f40a6600942b8 (MD5) Previous issue date: 2017-07-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Os extintores de combate a inc?ndio s?o equipamentos importantes que auxiliam no combate ao fogo. No intuito de maximizar a preven??o e minimizar os impactos oriundos de poss?veis sinistros, os extintores devem se encontrar com a recarga v?lida e n?o devem possuir nenhum tipo de avaria ou irregularidade que possa afetar seu desempenho durante o uso. Atualmente a maioria das ind?strias, com?rcios, laborat?rios e entre outros, n?o possuem um controle eficiente de todos os extintores de inc?ndio, pois ainda se utilizam como maneira de controle o aux?lio de planilhas manuais. A partir de estudo realizado, foi caracterizada a necessidade de se criar um sistema que fosse capaz de gerenciar as manuten??es dos extintores quanto a: vencimento das recargas, validade do teste hidrost?tico, irregularidades encontradas e que otimizasse o tempo de inspe??o. O software S.G.I realiza o gerenciamento das manuten??es dos extintores, utilizando-se de tecnologias Web e Mobile associadas a uma base de dados de geolocaliza??o dos extintores. A programa??o da parte Web foi desenvolvida atrav?s da linguagem PHP, com uso do framework gratuito denominado CakePHP. J? para o desenvolvimento do aplicativo mobile, foi utilizado a linguagem HTML5, CSS3 e JavaScript em um ambiente de desenvolvimento h?brido, que permite a constru??o e utiliza??o do aplicativo para multi-plataformas, sem que haja perda de desempenho para o usu?rio. Para realizar o teste do sistema desenvolvido, foi escolhido o laborat?rio de produ??o de medicamentos NUPLAM localizado na Universidade Federal do Rio Grande do Norte (UFRN), em virtude do grau de risco existente devido a manipula??o de compostos inflam?veis. / Fire extinguishers are important equipment that help in the fight against fire. In order to maximize prevention and minimize impacts from possible accidents, extinguishers must meet valid recharge and must not have any type of malfunction or irregularity that may affect their performance during use. Currently most industries, shops, laboratories and others, do not have an efficient control of all fire extinguishers, as the use of manual spreadsheets is still used as a control. From the study carried out, it was characterized the need to create a system that could manage the maintenance of extinguishers as to: expiration of the recharges, validity of the hydrostatic test, irregularities found and that optimized the time of inspection. S.G.I software manages fire extinguisher maintenance, using Web and Mobile technologies associated with a geolocation database of fire extinguishers. The programming of the Web part was developed through the PHP language, using the free framework called CakePHP. As for the development of the mobile application, HTML5, CSS3 and JavaScript were used in a hybrid development environment, which allows the construction and use of the application for multi-platforms, without loss of performance for the user. To carry out the test of the developed system, the NUPLAM drug production laboratory located at the Federal University of Rio Grande do Norte (UFRN) was chosen because of the degree of risk that exists due to the handling of flammable compounds.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-09-04T21:06:50Z No. of bitstreams: 1 IlmaraPinheiroLimao_DISSERT.pdf: 3934927 bytes, checksum: d25deddd20b654224a5b0b2be82ae163 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-09-06T23:07:01Z (GMT) No. of bitstreams: 1 IlmaraPinheiroLimao_DISSERT.pdf: 3934927 bytes, checksum: d25deddd20b654224a5b0b2be82ae163 (MD5) / Made available in DSpace on 2017-09-06T23:07:01Z (GMT). No. of bitstreams: 1 IlmaraPinheiroLimao_DISSERT.pdf: 3934927 bytes, checksum: d25deddd20b654224a5b0b2be82ae163 (MD5) Previous issue date: 2017-07-24 / A tribologia aplicada em materiais t?xteis apresenta uma significativa conex?o com o conforto da roupa, j? que as propriedades f?sicas dos tecidos est?o intimamente relacionadas ? sua superf?cie e propriedades de desgaste. De igual modo, o atrito na interface cadeira de rodas-t?xteis ? um fator cr?tico, para avarias das roupas e les?es de pele, causadas por cargas mec?nicas c?clicas, pelas press?es de contato e por for?as de cisalhamento, mediante cont?nuo e longo per?odo de tempo. Como os contatos mec?nicos podem ser especialmente problem?ticos, para usu?rios de cadeira de rodas, ? relevante conhecer as caracter?sticas de fric??o dos t?xteis, direcionada para pessoas com mobilidade reduzida. Diante do exposto, o presente trabalho tem por objetivo, analisar o material do assento e encosto de cadeiras de rodas dobr?veis, no que tange a tribologia. E propor novas rotas tecnol?gicas para a fabrica??o personalizada destes materiais. Para isso, foi realizada uma pesquisa de natureza aplicada, com abordagens qualitativa e quantitativa, utilizando dos procedimentos t?cnicos bibliogr?ficos e experimental, para descrever e explicar os ensaios mec?nicos, de resist?ncia ? tra??o e rasgo, forma??o de pilling, solidez ? cor por fric??o, al?m dos ensaios no abras?metro martindale e no trib?metro, pino sobre disco. Os materiais t?xteis analisados s?o de car?ter representativo, baseado nas caracter?sticas e propriedades da sua composi??o. As vari?veis analisadas s?o desgaste, coeficiente de atrito, for?a de atrito e temperatura. A an?lise e interpreta??o dos dados, ? auxiliada pela ferramenta de minera??o de dados Waikato Environment for Knowledge Analysis ? WEKA, utilizando o algoritmo de classifica??o J48. Resultou-se com o estudo, o mapeamento das avarias, elencando em ordem decrescente os materiais t?xteis mais adequados em contato com o assento de encosto de cadeira de rodas. Os resultados apresentaram: o tecido plano sarja, com maior resist?ncia em todos os ensaios; o tecido de malha jersey, com maior temperatura e forma??o de pilling; o tecido jeans, com maior desgaste abrasivo; o tecido tricoline, com maior coeficiente de atrito din?mico; o tecido tecnosport, com menor desgaste abrasivo. Sendo poss?vel tra?ar por meio do trabalho, novas rotas para fabrica??o de materiais t?xteis, voltadas para cadeirantes. / The tribology applied in textile materials presents a significant connection with the comfort of the clothes, since the physical properties of the fabrics are closely related to its surface and wear properties. Similarly, the friction in the wheelchair-textile interface is a critical factor, for clothing breakdowns and skin lesions, caused by cyclic mechanical loads, contact pressures and shear forces, for a continuous and long period of time. As mechanical contacts can be especially problematic for wheelchair users, it is relevant to know the friction characteristics of textiles, aimed at people with reduced mobility. In view of the above, the present work aims to analyze the material of the seat and backrest of folding wheelchairs, regarding tribology. And propose new technological routes for the personalized manufacture of these materials. For this, a research of an applied nature was carried out, with qualitative and quantitative approaches, using the technical bibliographical and experimental procedures, to describe and explain the mechanical tests, tensile and tear resistance, pilling formation, friction fastness, besides the tests on the martindale abrasometer and the tribometer, pin on disk. The textile materials analyzed are of representative character, based on the characteristics and properties of their composition. The analyzed variables are wear, coefficient of friction, friction force and temperature. Data analysis and interpretation is aided by the Waikato Environment for Knowledge Analysis (WEKA) data mining tool using the J48 classification algorithm. The study resulted in the mapping of faults, listing in decreasing order the most appropriate textile materials in contact with the seat of the back of a wheelchair. The results showed: the flat twill fabric, with higher resistance in all the tests; Knitted jersey fabric, with higher temperature and pilling formation; Jeans fabric with higher abrasive wear; The tricoline fabric, with higher coefficient of dynamic friction; The tecnosport fabric, with less abrasive wear. Being possible to draw through the work, new routes for the manufacture of textile materials, aimed at wheelchair users.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-09-19T20:22:46Z No. of bitstreams: 1 ClaraSilvestreDeSouza_TESE.pdf: 6901953 bytes, checksum: ee76c5acb89736663a8c651f4f8743b4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-09-20T20:59:29Z (GMT) No. of bitstreams: 1 ClaraSilvestreDeSouza_TESE.pdf: 6901953 bytes, checksum: ee76c5acb89736663a8c651f4f8743b4 (MD5) / Made available in DSpace on 2017-09-20T20:59:29Z (GMT). No. of bitstreams: 1 ClaraSilvestreDeSouza_TESE.pdf: 6901953 bytes, checksum: ee76c5acb89736663a8c651f4f8743b4 (MD5) Previous issue date: 2017-04-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Muito se pesquisa hoje sobre fontes renov?veis de energia e materiais sustent?veis, visando diminuir os impactos causados no ambiente. Rejeitos de materiais que antigamente tinham como destino o lixo, atualmente s?o vistos de outra forma. O presente trabalho teve por objetivo confeccionar um material geot?xtil utilizando folhas de bananeira, em particular, a fibra extra?da do caule da folha de bananeira que ? reconhecida atualmente como uma das mais fortes fibras celul?sicas. Como matriz desse geot?xtil natural, utilizou-se o l?tex e, posteriormente, foram analisadas as aplica??es para o geot?xtil mediante caracteriza??o do material pr?via baseada na literatura. Os corpos de prova foram tecidos e revestidos em l?tex e em seguida, foi realizada verifica??o e an?lise das principais propriedades f?sico-qu?micas, mec?nicas e t?rmicas. Tais propriedades foram obtidas atrav?s de testes como: Resist?ncia ? tra??o, Flamabilidade, Termogravimetria, Absor??o de ?gua e de umidade, Envelhecimento por ciclo e por umidade, Fric??o, Densidade Linear, Gramatura, Biodegrada??o e degrada??o ambiental e Condutividade T?rmica. Com base nos resultados das an?lises, foi poss?vel concluir que o geot?xtil pode ser utilizado como revestimento para superf?cies, pois al?m de resistente ? tra??o mesmo quando aquecido, o geot?xtil apresentou baixa condutividade t?rmica (0,241W/mK), fato que o torna isolante t?rmico. Foi ainda conclu?do que o comp?sito natural conseguiu aliar as propriedades de resist?ncia t?rmica e mec?nica da fibra da bananeira com o alongamento do elast?mero, l?tex. Tal resultado n?o comprometeu a higroscopicidade da fibra. P?de-se concluir finalmente que o material ? sustent?vel, n?o agride o meio ambiente e cumpre a fun??o esperada. / A lot is being researched nowadays about renewable sources of energy and sustainable materials that aim to decrease the impact caused on the environment. Materials rejected that once had the trash as destination, currently are seen in another way. This present paper had as purpose the confection of a geotextile using banana tree leaves, in particular, fibers extracted from the stem of the banana tree leaves, which presently, are recognized as one of the strongest cellulosic fibers. As a natural geotextile matrix, latex was used and, subsequently, possible applications for the geotextile were analysed through previous material characterization based on literature. Samples were weaved and coated in latex, and, soon after, a verification and analyses of physical, chemical, mechanical and thermal properties were made. Such properties were obtained throughout tests like: Tensile Strength, Flammability, Analysis Thermogravimetric (TG), Water and Humidity Absorption, Aging by Cycle and by Water, Abrasion, Linear Density, Grammage, Biodegradation, Environmental Degradation and Thermal Conductivity. According to the analysis results, it was possible to conclude that the geotextile can be used as surfaces coating, because beside being high tensile strength, even heated, the goetextile presented a low thermal conductivity (0,214W/mK). That fact means that the material is a thermal insulator. Also, it was conclude that the natural composite acquire the properties such as thermal and mechanical strength from the banana tree fibers combined with the elongation from thermoplastic elastomer latex. Such result did not compromise the hygroscopicity of the fiber. Finally, it could be concluded that the material is sustainable, does not damage the environment and fulfil the coating function, a characteristic expected.