Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-14T20:19:26Z No. of bitstreams: 1 IgorGuedesReboucas_DISSERT.pdf: 4109459 bytes, checksum: 9d05bc4fe3e1208e2195bfe4405550de (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-15T23:42:40Z (GMT) No. of bitstreams: 1 IgorGuedesReboucas_DISSERT.pdf: 4109459 bytes, checksum: 9d05bc4fe3e1208e2195bfe4405550de (MD5) / Made available in DSpace on 2016-06-15T23:42:40Z (GMT). No. of bitstreams: 1 IgorGuedesReboucas_DISSERT.pdf: 4109459 bytes, checksum: 9d05bc4fe3e1208e2195bfe4405550de (MD5) Previous issue date: 2015-12-17 / Este trabalho consiste na elabora??o de uma Rede Neural Artificial (RNA) com o fim de modelar o comportamento de comp?sitos quando submetidos a carregamento de fadiga. A proposta ? desenvolver e apresentar um modelo misto, que associa uma equa??o anal?tica (Equa??o de Adam) ? estrutura da RNA. Tendo em vista que os comp?sitos geralmente apresentam comportamentos semelhantes quando sujeitos a carregamentos flutuantes, essa equa??o visa estabelecer um padr?o pr?-definido de compara??o para um material gen?rico, a fim de que a RNA ajuste o comportamento de outro comp?sito a esse padr?o. Dessa forma, a RNA n?o precisaria aprender por completo o comportamento de determinado material, pois a Equa??o de Adam faria boa parte do trabalho. Este modelo foi utilizado em duas arquiteturas de rede diferentes, modular e perceptron, com o objetivo de analisar a sua efici?ncia em estruturas distintas. Al?m das diferentes arquiteturas, foram analisadas as respostas geradas a partir de dois conjuntos de dados diferentes ? com tr?s e duas curvas S-N. Esse modelo tamb?m foi comparado com os resultados da literatura especializada, que utilizam uma estrutura convencional de RNA. Os resultados consistem em analisar e comparar algumas caracter?sticas, como a capacidade de generaliza??o, a robustez e os Diagramas de Goodman, desenvolvidas pelas redes. / This work consists basically in the elaboration of an Artificial Neural Network (ANN) in order to model the composites materials? behavior when submitted to fatigue loadings. The proposal is to develop and present a mixed model, which associate an analytical equation (Adam Equation) to the structure of the ANN. Given that the composites often shows a similar behavior when subject to float loadings, this equation aims to establish a pre-defined comparison pattern for a generic material, so that the ANN fit the behavior of another composite material to that pattern. In this way, the ANN did not need to fully learn the behavior of a determined material, because the Adam Equation would do the big part of the job. This model was used in two different network architectures, modular and perceptron, with the aim of analyze it efficiency in distinct structures. Beyond the different architectures, it was analyzed the answers generated from two sets of different data ? with three and two SN curves. This model was also compared to the specialized literature results, which use a conventional structure of ANN. The results consist in analyze and compare some characteristics like generalization capacity, robustness and the Goodman Diagrams, developed by the networks.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-23T20:06:05Z No. of bitstreams: 1 DiegoDeLimaSousa_DISSERT.pdf: 2208966 bytes, checksum: 2885ffd2a2607c0a81d1654eca74abed (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-27T20:16:49Z (GMT) No. of bitstreams: 1 DiegoDeLimaSousa_DISSERT.pdf: 2208966 bytes, checksum: 2885ffd2a2607c0a81d1654eca74abed (MD5) / Made available in DSpace on 2016-06-27T20:16:49Z (GMT). No. of bitstreams: 1 DiegoDeLimaSousa_DISSERT.pdf: 2208966 bytes, checksum: 2885ffd2a2607c0a81d1654eca74abed (MD5) Previous issue date: 2016-01-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A medi??o de vaz?o atrav?s da predi??o da press?o diferencial ? amplamente utilizada no dia-a-dia industrial, isso acontece, principalmente, devido ao fato de ser utilizado para os mais variados tipos de fluidos, tais como: fluxo de gases e l?quido com viscosidades distintas, at? mesmo, escoamento de fluidos com part?culas em suspens?o. A adequa??o desses equipamentos para a medi??o de vaz?o m?ssica em escoamentos bif?sicos ? de suma import?ncia para o desenvolvimento tecnol?gico e confiabilidade dos resultados. Quando se trata de escoamentos bif?sicos as rela??es existentes entre os fluidos e as intera??es entre eles s?o de suma import?ncia na predi??o da vaz?o. No presente trabalho, ? proposto a utiliza??o de placa de orif?cio conc?ntrica utilizada em tubula??es de pequenos di?metros da ordem de 25,4 mm onde escoa um fluxo bif?sico de ?gua e ar. A medi??o de vaz?o monof?sica foi feita com a utiliza??o dos dados referentes na norma NBR 5167-1 onde utilizou-se a equa??o de Stolz para a mensura??o do coeficiente de descarga. No escoamento bif?sico foi utilizado duas correla??es largamente empregadas no progn?stico da vaz?o m?ssica, o padr?o de Zhang (1992), e o modelo de Chisholm (1967), para o modelo de escoamento homog?neo. Observou-se que o comportamento encontrado no modelo de Zhang, condizem de forma mais real?stica a vaz?o m?ssica do fluxo bif?sico, pois, o modelo de Chisholm extrapola nos par?metros para a press?o a jusante, P2, a placa de orif?cio, assim como o coeficiente de descarga avaliada. A utiliza??o da modifica??o nas quedas de press?o, P1-P2, e coeficiente de descarga, permitiu uma melhor converg?ncia entre os valores obtidos para o fluxo bif?sico ?gua-ar. / The measurement of flow through the prediction of differential pressure is widely used in industrial day-to-day, this happens mainly due to the fact that it is used for various types of fluids, such as gas flow and liquid with viscosity distinct even flow of fluids with particles in suspension. The suitability of this equipment for measuring mass flow in two-phase flow is of paramount importance for technological development and reliability of results. When it comes to two-phase flow the relationship between the fluids and their interactions are of paramount importance in predicting the flow. In this paper, we propose the use of concentric orifice plate used in small diameter pipes of 25.4 mm order where a two-phase flow flows between water-air. The measurement of single-phase flow was made with the use of data in NBR 5167-1 which was used to Stolz equation for measuring discharge coefficient. In the two-phase flow was used two correlations widely used in the prognosis of mass flow, the pattern of Zhang (1992) and the model of Chisholm (1967), to the homogeneous flow model. It was observed that the behavior found in Zhang model are consistent more realistic way the mass flow of two-phase flow, since the model Chisholm extrapolate the parameters for the downstream pressure P2, the orifice plate, and the rated discharge coefficient. The use of the change in pressure drop P1-P2 and discharge coefficient, led to a better convergence of the values obtained for the two-phase air-water stream.

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 2016-06-23T20:06:05Z No. of bitstreams: 1 RodrigoAndersonDePaiva_DISSERT.pdf: 4677392 bytes, checksum: 53c9a2ed52e973cf1c11c1a653e28ed4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-27T20:37:10Z (GMT) No. of bitstreams: 1 RodrigoAndersonDePaiva_DISSERT.pdf: 4677392 bytes, checksum: 53c9a2ed52e973cf1c11c1a653e28ed4 (MD5) / Made available in DSpace on 2016-06-27T20:37:11Z (GMT). No. of bitstreams: 1 RodrigoAndersonDePaiva_DISSERT.pdf: 4677392 bytes, checksum: 53c9a2ed52e973cf1c11c1a653e28ed4 (MD5) Previous issue date: 2015-12-17 / A necessidade da ind?stria do petr?leo de garantir a seguran?a das instala??es, empregados e meio ambiente, sem esquecer a busca pela m?xima efici?ncia das suas instala??es, faz com que se busque atingir um alto n?vel de excel?ncia em todas as etapas de seus processos produtivos a fim de se obter a qualidade requerida do seu produto final. Conhecer a confiabilidade de um equipamento e o que esta representa para um sistema ? de fundamental import?ncia para a garantia da seguran?a operacional. A t?cnica de analise de confiabilidade vem sendo cada vez mais aplicada na ind?stria do petr?leo como ferramenta de predile??o de falhas e eventos indesej?veis que podem afetar a continuidade operacional. ? uma metodologia cientifica aplicada que envolve conhecimentos nas ?reas de Engenharia e Estat?stica para conhecer e ou analisar a performance de componentes, equipamentos ou sistemas, de forma a assegurar que estes executem sua fun??o, sem falhar, por um per?odo de tempo determinado e sob uma condi??o especifica. Os resultados das analises de confiabilidade auxiliam na tomada de decis?o acerca da melhor estrat?gia de manuten??o das plantas petroqu?micas. A an?lise de confiabilidade foi aplicada em um equipamento (moto-ventilador centr?fugo) entre o per?odo de 2010 a 2014 no Polo Industrial Petrobras de Guamar?, situado na zona rural do munic?pio de Guamar? no estado do Rio Grande do Norte, onde foram coletados dados de campo, analisado hist?rico do equipamento e observado o comportamento das falhas e seus impactos. Os dados obtidos foram processados em software comercial de confiabilidade. Os resultados obtidos foram comparados com uma pesquisa realizada junto aos especialistas da ?rea a fim de se obter a melhor estrat?gia de manuten??o para o sistema estudado. As an?lises foram satisfat?rias e comprovaram a efic?cia da aplica??o da metodologia, apontando possibilidades de ganhos relevantes e melhoria no plano de manuten??o dos equipamentos, bem como, aumento significativo da confiabilidade dos equipamentos analisados. / The need of the oil industry to ensure the safety of the facilities, employees and the environment, not to mention the search for maximum efficiency of its facilities, makes it seeks to achieve a high level of excellence in all stages of its production processes in order to obtain the required quality of the final product. Know the reliability of equipment and what it stands for a system is of fundamental importance for ensuring the operational safety. The reliability analysis technique has been increasingly applied in the oil industry as fault prediction tool and undesirable events that can affect business continuity. It is an applied scientific methodology that involves knowledge in engineering and statistics to meet and or analyze the performance of components, equipment and systems in order to ensure that they perform their function without fail, for a period of time and under a specific condition. The results of reliability analyzes help in making decisions about the best maintenance strategy of petrochemical plants. Reliability analysis was applied on equipment (bike-centrifugal fan) between the period 2010-2014 at the Polo Petrobras Guamar? Industrial, situated in rural Guamar? municipality in the state of Rio Grande do Norte, where he collected data field, analyzed historical equipment and observing the behavior of faults and their impacts. The data were processed in commercial software reliability ReliaSoft BlockSim 9. The results were compared with a study conducted by the experts in the field in order to get the best maintenance strategy for the studied system. With the results obtained from the reliability analysis tools was possible to determine the availability of the centrifugal motor-fan and what will be its impact on the security of process units if it will fail. A new maintenance strategy was established to improve the reliability, availability, maintainability and decreased likelihood of Moto-Centrifugal Fan failures, it is a series of actions to promote the increased system reliability and consequent increase in cycle life of the asset. Thus, this strategy sets out preventive measures to reduce the probability of failure and mitigating aimed at minimizing the consequences.

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 2016-07-08T21:06:56Z No. of bitstreams: 1 CaioJulioCesarDoValeFernandesDaSilva_DISSERT.pdf: 5841265 bytes, checksum: b45c3017ad558e351b1dbe31689d6c95 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-12T19:16:48Z (GMT) No. of bitstreams: 1 CaioJulioCesarDoValeFernandesDaSilva_DISSERT.pdf: 5841265 bytes, checksum: b45c3017ad558e351b1dbe31689d6c95 (MD5) / Made available in DSpace on 2016-07-12T19:16:48Z (GMT). No. of bitstreams: 1 CaioJulioCesarDoValeFernandesDaSilva_DISSERT.pdf: 5841265 bytes, checksum: b45c3017ad558e351b1dbe31689d6c95 (MD5) Previous issue date: 2015-12-17 / A explora??o de petr?leo em profundidades elevadas requer o uso de rob?s m?veis para realizar opera??es diversas, como manuten??o, montagem etc. Nesse contexto, o estudo do planejamento de trajet?rias e navega??o desses rob?s se faz relevante, visto o grande desafio que ? navegar em um ambiente que n?o ? totalmente conhecido. Assim, este trabalho tem o objetivo de criar um algoritmo de navega??o, que deve realizar o planejamento da trajet?ria de um rob? m?vel que se encontra em uma dada posi??o (x, y) e deve atingir a posi??o desejada (x_d, y_d), evitando, no entanto, a colis?o com qualquer obst?culo existente no caminho. Para a gera??o da rota global foi utilizado um algoritmo gen?tico (offline), que leva em considera??o apenas as coordenadas dos pontos a serem visitados. Para desviar dos poss?veis obst?culos no caminho, o rob? deve gerar rotas locais baseadas nas curvas de B?zier (online). Na implementa??o do programa n?o h? qualquer informa??o sobre a localiza??o ou o formato dos obst?culos, mesmo assim, o rob? deve evitar os obst?culos, baseadas nas informa??es dos sensores de proximidade. Esta estrat?gia ? v?lida na situa??o em que os obst?culos s?o pequenos em rela??o as dist?ncias entre os pontos de visita??o. Os resultados das simula??es e experimentos com um rob? m?vel real (Robotino) demonstraram que o rob? foi capaz de realizar o percurso definido pelo algoritmo gen?tico, desviando dos obst?culos atrav?s de curvas de B?zier e atingindo as posi??es desejadas dentro da margem de erro definida como aceit?vel. As principais contribui??es deste trabalho est?o no c?lculo online das curvas de B?zier no planejador de rotas locais, atrelado a um planejador de rotas global, com obten??o de resultados experimentais. / Oil exploration at great depths requires the use of mobile robots to perform various operations such as maintenance, assembly etc. In this context, the trajectory planning and navigation study of these robots is relevant, as the great challenge is to navigate in an environment that is not fully known. The main objective is to develop a navigation algorithm to plan the path of a mobile robot that is in a given position (?, ?) and should reach the desired position (??, ??) avoiding colision with any obstacle standing in the way. The global route was generated using a genetic algorithm, which takes into account only the coordinates of the checkpoints. The mobile robot path generation based on B?zier curves was able to dodge the possible obstacles in the way. There was no information about the obstacles?s shape or location during the implementation of the program yet the robot must generate local path based on information from proximity sensors located around the robot to be able to avoid collisions. This strategy is valid in the situation where the obstacles are small relative distances between the visited sites. The results of simulations and experiments with a real mobile robot shown that the robot was able to perform the route defined by the genetic algorithm, dodging obstacles by Bezier curves and reaching the desired positions within the margin of error defined as acceptable. The main contributions of this work are the equations used to define the control points in the online calculation of Bezier curves in the planner of local routes, linked to a global route planner with obtaining experimental results.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-08T21:06:56Z No. of bitstreams: 1 FabioPimentaDeLira_DISSERT.pdf: 2588802 bytes, checksum: 309b81889459c9056d686910dd512bf9 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-12T19:50:05Z (GMT) No. of bitstreams: 1 FabioPimentaDeLira_DISSERT.pdf: 2588802 bytes, checksum: 309b81889459c9056d686910dd512bf9 (MD5) / Made available in DSpace on 2016-07-12T19:50:05Z (GMT). No. of bitstreams: 1 FabioPimentaDeLira_DISSERT.pdf: 2588802 bytes, checksum: 309b81889459c9056d686910dd512bf9 (MD5) Previous issue date: 2015-11-30 / O presente estudo trata de uma an?lise, em car?ter experimental, do consumo de combust?vel de um veiculo flex, operando com diferentes misturas de gasolina e etanol em tr?fego urbano, o que permite obter resultados mais condizentes com a realidade do motorista, haja vista que os ?ndices de consumo aferidos pelo INMETRO n?o levam em considera??o o real cen?rio que a popula??o enfrenta diariamente em seus deslocamentos urbanos, possibilitando assim a escolha mais economicamente vi?vel da mistura gasolina/etanol, acarretando numa redu??o dos custos e, possivelmente, uma diminui??o nos ?ndices de emiss?o de poluentes. Atualmente, os fabricantes de ve?culos flex recomendam o abastecimento com etanol, caso o valor deste n?o ultrapasse 70% do valor da gasolina comum, entretanto, os ve?culos com a tecnologia flex, possibilitam operar com qualquer percentual de mistura no tanque de combust?vel, por?m, hoje, muitos dos propriet?rios desses ve?culos n?o utilizam esse recurso com efici?ncia, por desconhecerem essa possibilidade de mistura ou pela raz?o de n?o existir um estudo mais profundo em rela??o ao percentual ideal da mistura que proporcione um maior rendimento com um custo inferior ao proposto pelos fabricantes. / This study is an analysis, on a trial basis, the fuel consumption of a Flex vehicle, operating with different mixtures of gasoline and ethanol in urban traffic, allowing more consistent results with the reality of the driver. Considering that most owners unaware of the possibility of mixing the fuel at the time of supply, thus enabling the choice of the most economically viable mixing gasoline / ethanol, resulting in lower costs and possibly a decrease in pollutant emission rates. Currently, there is a myth created by the people that supply ethanol only becomes viable if the value of not more than 70% of regular gasoline. However vehicles with this technology make it possible to operate with any percentage of mixture in the fuel tank, but today many of the owners of these vehicles do not use this feature effectively, because they ignore the possibility of mixing or the reason there is a deeper study regarding the optimal percentage of the mixture to provide a higher yield with a lower cost than proposed by the manufacturers.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-08T21:06:57Z No. of bitstreams: 1 LuizaMariaPinheiroDosSantos_DISSERT.pdf: 2578153 bytes, checksum: 8f88a1b510f4e5eb7384d64661cfb4e8 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-12T20:11:44Z (GMT) No. of bitstreams: 1 LuizaMariaPinheiroDosSantos_DISSERT.pdf: 2578153 bytes, checksum: 8f88a1b510f4e5eb7384d64661cfb4e8 (MD5) / Made available in DSpace on 2016-07-12T20:11:44Z (GMT). No. of bitstreams: 1 LuizaMariaPinheiroDosSantos_DISSERT.pdf: 2578153 bytes, checksum: 8f88a1b510f4e5eb7384d64661cfb4e8 (MD5) Previous issue date: 2015-11-24 / O desenvolvimento de materiais comp?sitos abrange as mais diversas ?reas de aplica??o. Dentre os comp?sitos, t?m-se, especialmente, os materiais de origem org?nica, que possuem maior potencial de biodegrabilidade e por isso t?m apresentado relev?ncia e destaque no cen?rio contempor?neo de preserva??o ambiental e desenvolvimento sustent?vel. Seguindo essa perspectiva de apelo ecol?gico, foram desenvolvidos comp?sitos com insumos naturais brasileiros. Esses comp?sitos foram fabricados com l?tex (borracha natural) e fibra de carna?ba, em diferentes propor??es m?ssicas. As formula??es variaram em 5%, 10%, 15% e 20% de fibra em rela??o ? matriz. Esses materiais foram concebidos visando aplica??o em sistemas de isolamentos t?rmicos que requeiram prote??o t?rmica de superf?cies e/ou redu??o de perda de energia t?rmica. Para tanto, os comp?sitos foram caracterizados atrav?s de ensaios t?rmicos de condutividade, calor espec?fico, difusividade e termogravimetria. Assim como, tamb?m foram caracterizados quanto aos seus aspectos f?sico-mec?nicos, atrav?s de ensaios de densidade, teor de umidade, resist?ncia ? tra??o e dureza. A caracteriza??o dos materiais revelou que a os comp?sitos apresentam potencial de isolamento t?rmico superior ao da borracha natural que foi utilizada como refer?ncia. Dessa forma, os materiais comp?sitos em quest?o apresentam-se como alternativa vi?vel e eficaz de concep??o de novo material isolante t?rmico. / The development of composite materials encompasses many different application areas. Among the composites, it is had, especially, the materials of organic origin, which have the greatest potential for biodegradability and so, have been bringing relevance and prominence in the contemporary setting of environmental preservation and sustainable development. Following this perspective of ecological appeal, it was developed a biocomposite material with natural inputs typically brazilian. This composite was made from latex (natural rubber) and carnauba fiber in different mass proportions. Formulations had varied by 5%, 10%, 15% and 20% of fiber in relation the matrix. This material has been designed aiming at application in thermal insulation systems, which requirethermal protection surfaces and/or reduction of thermal energy loss. Therefore, the composite was characterized by thermal conductivity testing, specific heat, thermal diffusivity and thermogravimetry. As has also been characterized for their physical-mechanical, by testing density, moisture content, tensile strength, hardness and scanning electron microscopy (SEM). The characterization of the material revealed that the composite presents a potential of thermal insulation higher than the natural rubber, that was used as reference. And the formulation at 15% fiber in relation the matrix showed the best performance. Thus, the composite material in question presents itself as a viable and effective alternative for new thermal insulation material design.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-08T21:06:57Z No. of bitstreams: 1 LuizPauloDeOliveiraQueiroz_DISSERT.pdf: 2136426 bytes, checksum: 522731129ac7437c10bd9e82c9e5ca65 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-12T20:37:04Z (GMT) No. of bitstreams: 1 LuizPauloDeOliveiraQueiroz_DISSERT.pdf: 2136426 bytes, checksum: 522731129ac7437c10bd9e82c9e5ca65 (MD5) / Made available in DSpace on 2016-07-12T20:37:04Z (GMT). No. of bitstreams: 1 LuizPauloDeOliveiraQueiroz_DISSERT.pdf: 2136426 bytes, checksum: 522731129ac7437c10bd9e82c9e5ca65 (MD5) Previous issue date: 2016-02-16 / Escoamentos turbulentos e laminares s?o encontrados, frequentemente, em diversas aplica??es de engenharia, como em compressores e bombas e ao redor de carros, avi?es e navios. O atrito superficial, grande respons?vel pelas perdas energ?ticas, ? consideravelmente maiores no tipo de escoamento turbulento do que em escoamentos laminares. Seu estudo ? bastante desafiador, devido a sua natureza complexa. A principal justificativa para este estudo baseia-se na otimiza??o dos recursos energ?ticos, por motivos econ?micos principalmente, atrav?s do estudo da redu??o de arrasto induzido por pol?meros. Neste trabalho, ? estudada a redu??o de arrasto por indu??o de pol?meros a partir da utiliza??o de uma bancada experimental situada no laborat?rio de mec?nica dos fluidos da UFRN. A bancada experimental foi constru?da e calibrada exclusivamente para este trabalho. Foram utilizados como aditivos polim?ricos o Polietileno glicol 4000, o Polyox WSR N60K, Polyox WSR 301 e o Polyox WSR 205. A redu??o de arrasto induzida por pol?meros ? investigada a partir da an?lise de um escoamento, tal an?lise parte do princ?pio da medi??o de press?o em dois pontos do escoamento e culmina no c?lculo da perda de carga e do fator de atrito, o que possibilita analisar a influ?ncia da adi??o de pol?meros na redu??o do arrasto em escoamentos sejam eles laminares ou turbulentos. N?o foi observado redu??o de arrasto no polietileno glicol 4000 na concentra??o analisada. O Polyox WSR N60K, o Polyox WSR 301 e o Polyox WSR 205 apresentaram redu??o de arrasto com destaque para o Polyox WSR 301 que apresentou maior redu??o dentre dos pol?meros estudados, o que conclui-se que o Polyox WSR 301 ? mais eficiente para promover a redu??o de arrasto em tubos r?gidos. / The flows turbulent and laminar are present in various applications of engineering and one of the villain of energy loss big is the surface friction. Currently, there are several research aimed for the study of reducing drag (DR) with the objective of developing effective methods to reduce the friction. Regardless of numerous research carried out until today, the phenomenon DR still remains in study not it is fully understood. This paper studied the drag reduction by polymer induction in turbulent internal flows in ducts. We constructed a testing bench to perform the analysis of drag reduction, the bench has basically two manometers with a 8.5 psi full scale, a peripheral pump 0.5 HP, an acrylic tank, valves and tubes pvc and is situated in the Laboratory Fluid Mechanics UFRN. Were used as polymer additives to polyethylene glycol 4000, the Polyox WSR N60K, Polyox WSR 301 and Polyox WSR 205. The rationale for the choice of these polymers is their wide application in situations requiring greater energy efficiency, such as the addition reducing polymers for the jet used by the fire department to achieve greater distances. The induced drag reduction polymers is investigated from the turbulent flow analysis, with Reynolds number in a range between 2?104 ? 5?104. The part of the first pressure measurement analysis on two points of the turbulent flow, then the density measurements, viscosity of the polymer solutions and culminates in drag reduction calculation, allowing to analyze the influence of the addition polymer in reducing the drag in turbulent flows. The Polyox WSR N60K, the Polyox WSR 301 and Polyox WSR 205 decreased drag highlighting the Polyox WSR 301 that showed the greatest reduction among the polymers studied, which concluded that the Polyox WSR 301 is more efficient to drag reduction in pipes. There was no drag reduction in polyethylene glycol 4000 to the measured concentration.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-22T15:34:02Z No. of bitstreams: 1 MarianaLimaDeOliveira_DISSERT.pdf: 1436779 bytes, checksum: b40fe8dddf1d23473972fa9553244479 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-27T22:37:51Z (GMT) No. of bitstreams: 1 MarianaLimaDeOliveira_DISSERT.pdf: 1436779 bytes, checksum: b40fe8dddf1d23473972fa9553244479 (MD5) / Made available in DSpace on 2016-07-27T22:37:51Z (GMT). No. of bitstreams: 1 MarianaLimaDeOliveira_DISSERT.pdf: 1436779 bytes, checksum: b40fe8dddf1d23473972fa9553244479 (MD5) Previous issue date: 2015-12-29 / Foi estudada a viabilidade do uso do farelo do sabugo de milho para a obten??o de um comp?sito de matriz polim?rica. Foram utilizadas tr?s granulometrias e algumas formula??es entre os elementos constituintes do comp?sito, resina poli?ster e farelo do sabugo de milho e determinada qual a formula??o mais adequada levando-se em conta par?metros mec?nicos e t?rmicos. Para a obten??o do farelo, o sabugo passou pelo processo de secagem em secador solar e posteriormente foi triturado numa forrageira, obtendo-se diferentes granulometria atrav?s de peneiramento. Para a caracteriza??o do comp?sito ser?o determinadas propriedades t?rmicas e mec?nicas. A principal vantagem do comp?sito proposto foi sua baixa densidade, abaixo da relativa a resina, em torno de 1,06 Kg/m? para a formula??o com P? Grosso. O comp?sito apresentou comportamento mec?nico inferior ao da resina para todas as granulometrias e formula??es estudadas. Apresentou resultados melhores para a flex?o, alcan?ando 25,3 MPa para o P? Grosso. O comp?sito tamb?m se demonstrou vi?vel para aplica??es t?rmicas, com condutividade t?rmica inferior a 0,21 W/m, classificando-se como isolante t?rmico. Em termos de homogeneidade da mistura a granulometria mais vi?vel ? a PF 20%, que tamb?m apresentou melhor est?tica e uma melhor processabilidade. Tal comp?sito pode ser utilizado para a fabrica??o de estruturas que n?o requeiram significativa resist?ncia mec?nica, como por exemplo, mesas, cadeiras, pranchas, e prot?tipos solares e e?licos, como fornos e fog?es solares e p?s de aero geradores. / The feasibility of using the corn cob to obtain a polymer matrix composite was studied. To obtain the bran, corncob passed the drying process in a solar dryer, and was subsequently triturated in forage and to obtain the different particle sizes, by sieving. Three different grain sizes were used: fine particles (FP) size between 0,10 and 2mm; sized particles (PM) with sizes between 2,10 and 3,35 mm; large particles (PG) sizes between 3,45 and 4,10 mm. Using 20% of residue relative to the resin, the test samples were constructed for characterization of the composite, taking into account thermal and mechanical parameters. The main advantage of the proposed composite is that it has a low density, below the relative resin, about 1.06 kg / m? for the PG. The composite showed a mechanical behavior less than of the resin to the grain sizes and for all formulations studied. Showed better results for the bending, reaching 25.3 MPa for the PG. The composite also showed be feasible for thermal applications, with thermal conductivity less than 0.21 W / m, ranking as insulation. In terms of homogeneity of the mixture, the most viable grain size is the PF, which also showed improved aesthetics and better processability. This composite can be used to make structures that do not require significant mechanical strength, such as tables, chairs, planks, and solar and wind prototypes, such as ovens and cookers and turbines blades.