Made available in DSpace on 2014-12-17T14:48:13Z (GMT). No. of bitstreams: 1 JulioCCD_DISSERT.pdf: 5293520 bytes, checksum: 35065f2bef6951ad4ce1b2b752aa3b02 (MD5) Previous issue date: 2012-02-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The main objective of this thesis was the study of bracing panels of structural masonry, by applying the Finite Element Method and Strut and Tie Method. It was analyzed the following aspects: the effect of orthotropy on the behavior of the panels; distribution of horizontal forces between panels for buildings; comparison between Equivalent Frame and Finite Elements models; panels design with the Strut and Tie Method. The results showed that one should not disregard the orthotropy, otherwise this can lead to models stiffer than the real. Regarding the distribution of horizontal forces, showed that the disregard of lintels and shear deformation leads to significant differences in the simplified model. The results showed also that the models in Finite Element and Equivalent Frame exhibit similar behavior in respect to stiffness of panels and stress distribution over the sessions requested. It was discussing criteria for designing Strut and Tie Method models in one floor panels. Then, the theoretical strength these panels was compared with the rupture strength of panels tested in the literature. The theoretical maximum strength were always less than the rupture strength of the panels obtained in tests, due to the fact that the proposed model cannot represent the behavior of the masonry after the start of the panel cracking due to plasticization of the reinforcement / O objetivo principal desta disserta??o foi o estudo de pain?is de contraventamento de alvenaria estrutural, atrav?s da aplica??o do M?todo dos Elementos Finitos e do M?todo de Bielas e Tirantes. Foram analisados os seguintes aspectos: o efeito da ortotropia no comportamento de pain?is; distribui??o de for?as horizontais entre pain?is de edif?cios; compara??o entre os modelos de P?rtico Equivalente e Elementos Finitos; c?lculo de pain?is com o M?todo de Bielas e Tirantes. Os resultados permitiram concluir que n?o se deve desconsiderar a ortotropia, sob pena de conduzir a modelos mais r?gidos que o real. Em rela??o ? distribui??o de for?as horizontais, evidenciou-se que a desconsidera??o dos lint?is e da deforma??o por cisalhamento acarretam diferen?as significativas relativamente ao modelo de barras isoladas. Os resultados permitiram concluir, ainda que os modelos em Elementos Finitos e de P?rtico Equivalente apresentam comportamento semelhante no que se refere ? rigidez de pain?is e distribui??o de tens?es nas sess?es mais solicitadas. Foram discutidos crit?rios para a concep??o de modelos de bielas e tirantes em pain?is isolados. Em seguida, a for?a horizontal te?rica destes pain?is foi comparada com a carga de ruptura de pain?is ensaiados dispon?veis na literatura. As for?as m?ximas te?ricas foram sempre inferiores ? for?a de ruptura dos pain?is, obtidas em ensaios, devido ao fato de que o modelo proposto n?o ? capaz de representar o comportamento da alvenaria ap?s o inicio da fissura??o do painel devido ? plastifica??o das armaduras

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-16T22:41:17Z No. of bitstreams: 1 JoaoPauloDeBarrosCavalcante_DISSERT.pdf: 25549974 bytes, checksum: 7d7077941a19b96d7263afec72ec7622 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-23T23:20:29Z (GMT) No. of bitstreams: 1 JoaoPauloDeBarrosCavalcante_DISSERT.pdf: 25549974 bytes, checksum: 7d7077941a19b96d7263afec72ec7622 (MD5) / Made available in DSpace on 2016-08-23T23:20:29Z (GMT). No. of bitstreams: 1 JoaoPauloDeBarrosCavalcante_DISSERT.pdf: 25549974 bytes, checksum: 7d7077941a19b96d7263afec72ec7622 (MD5) Previous issue date: 2016-03-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O presente trabalho consiste na an?lise num?rica via M?todo dos Elementos Finitos (MEF) de treli?as submetidas a carregamentos t?rmicos, mec?nicos e suas respectivas intera??es. A metodologia proposta baseia-se no teorema da m?nima energia potencial, escrita em rela??o as posi??es nodais ao inv?s dos deslocamentos para lidar com problemas termomec?nicos, levando-se em considera??o os efeitos das n?o linearidades f?sica e geom?trica. Referente aos problemas din?micos, a solu??o da equa??o de equil?brio ? alcan?ada atrav?s da discretiza??o temporal perante diferentes algoritmos de integra??o temporal, expl?citos e impl?citos. A formula??o ? estendida para problemas de impacto entre treli?as e anteparo r?gido, onde as posi??es nodais s?o restringidas atrav?s da condi??o de penetra??o nula. Sendo assim, apresenta-se uma formula??o termodinamicamente consistente, fundamentada na primeira e segunda lei da termodin?mica e na energia livre de Helmholtz, para analisar problemas din?micos de estruturas treli?adas com comportamento termoel?stico e termopl?stico. A implementa??o dos problemas consiste no desenvolvimento de rotinas computacionais, sendo os resultados num?ricos da formula??o proposta confrontados com exemplos encontrados na literatura especializada. / This work presents the numerical analysis of nonlinear trusses summited to thermomechanical actions with Finite Element Method (FEM). The proposed formulation is so-called positional FEM and it is based on the minimum potential energy theorem written according to nodal positions, instead of displacements. The study herein presented considers the effects of geometric and material nonlinearities. Related to dynamic problems, a comparison between different time integration algorithms is performed. The formulation is extended to impact problems between trusses and rigid wall, where the nodal positions are constrained considering nullpenetration condition. In addition, it is presented a thermodynamically consistent formulation, based on the first and second law of thermodynamics and the Helmholtz free-energy for analyzing dynamic problems of truss structures with thermoelastic and thermoplastic behavior. The numerical results of the proposed formulation are compared with examples found in the literature.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-11T20:48:07Z No. of bitstreams: 1 ErnestoCidBrasilDeMatos_TESE.pdf: 4062332 bytes, checksum: 09e4f284f102ad1088f37213e8e53d6f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-10-14T00:17:49Z (GMT) No. of bitstreams: 1 ErnestoCidBrasilDeMatos_TESE.pdf: 4062332 bytes, checksum: 09e4f284f102ad1088f37213e8e53d6f (MD5) / Made available in DSpace on 2016-10-14T00:17:49Z (GMT). No. of bitstreams: 1 ErnestoCidBrasilDeMatos_TESE.pdf: 4062332 bytes, checksum: 09e4f284f102ad1088f37213e8e53d6f (MD5) Previous issue date: 2016-04-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Sistemas de software esta?o presentes em grande parte das nossas vidas atualmente e, mais do que nunca, eles requerem um alto ni?vel de confiabilidade. Existem va?rias te?cnicas de Ver- ificac?a?o e Validac?a?o (V&V) de software que se preocupam com controle de qualidade, segu- ranc?a, robustez e confiabilidade; as mais conhecidas sa?o Testes de Software e Me?todos For- mais. Me?todos formais e testes sa?o te?cnicas que podem se complementar. Enquanto me?to- dos formais prove?em mecanismos confia?veis para raciocinar sobre o sistema em um ni?vel mais abstrato, te?cnicas de teste ainda sa?o necessa?rias para uma validac?a?o mais profunda e sa?o frenquentemente requeridas por orga?os de certificac?a?o. Levando isto em considerac?a?o, BETA prove? uma abordagem de testes baseada em modelos para o Me?todo B, suportada por uma ferramenta, que e? capaz de gerar testes de unidade a partir de ma?quinas abstratas B. Nesta tese de doutorado apresentamos melhorias realizadas em BETA e novos estudos de caso realizados para avalia?-la. Dentre as melhorias, integramos crite?rios de cobertura lo?gicos a? abordagem, revisamos os crite?rios de cobertura baseados em espac?o de entrada que ja? eram suportados e aperfeic?oamos as u?ltimas etapas do processo de gerac?a?o de testes. A abordagem agora suporta a gerac?a?o automa?tica de dados para os ora?culos e prea?mbulos para os casos de teste; ela tambe?m possui uma funcionalidade para concretizac?a?o dos da- dos de teste e um mo?dulo para gerar scripts de teste executa?veis automaticamente. Outro objetivo desta tese foi realizar estudos de caso mais complexos utilizando BETA e avaliar a qualidade dos casos de teste que a abordagem produz. Estes estudos de caso foram os primeiros a avaliar o processo de gerac?a?o de testes por completo, desde a especificac?a?o dos casos de teste ate? a sua implementac?a?o e execuc?a?o. Em nossos u?ltimos experimentos, analisamos a qualidade dos casos de teste gerados por BETA, considerando cada crite?rio de cobertura suportado, utilizando me?tricas de cobertuda de co?digo como cobertura de in- struc?o?es e ramificac?o?es. Tambe?m utilizamos testes de mutac?a?o para avaliar a capacidade dos casos de teste de detectar faltas na implementac?a?o dos modelos. O resultados obtidos foram promissores mostrando que BETA e? capaz de detectar faltas introduzidas por progra- madores ou geradores de co?digo e que a abordagem pode obter bons resultados de cobertura para a implementac?a?o de um sistema baseado em modelos B. / Software systems are a big part of our lives and, more than ever, they require a high level of reliability. There are many software Verification and Validation (V&V) techniques that are concerned with quality control, security, robustness, and reliability; the most widely known are Software Testing and Formal Methods. Formal methods and testing are techniques that can complement each other. While formal methods provide sound mechanisms to reason about the system at a more abstract level, testing techniques are still necessary for a more in-depth validation of the system and are often required by certification standards. Taking this into consideration, BETA provides a tool-supported, model-based testing approach for the B Method that is capable of generating unit tests from abstract B machines. In this thesis, we present improvements made in the BETA approach and tool, and new cases studies used to evaluate them. Among these improvements, we integrated logical coverage criteria into the approach, reviewed the input space criteria that was already supported, and enhanced the final steps of the test generation process. The approach now has support for automatic generation of oracle data and test case preambles, it has a feature for test data concretization, and a module that automatically generates executable test scripts. Another objective of this thesis was to perform more complex case studies using BETA and assess the quality of the test cases it produces. These case studies were the first to evaluate the test generation process as a whole, from test case design to implementation and execution. In our last experiments, we assessed the quality of the test cases generated by BETA, considering each coverage criteria it supports, using code coverage metrics such as statement and branch coverage. We also used mutation testing to evaluate the ability of the generated test cases to identify faults in the model?s implementation. The results obtained were promising, showing that BETA is capable of detecting faults introduced by a programmer or code generation tool and that it can achieve good coverage results for a system?s implementation based on a B model.

Submitted by PPG Administra??o e Neg?cios (ppgad@pucrs.br) on 2018-11-20T19:28:09Z No. of bitstreams: 1 JOSIANE_BRIETZKE_PORTO_TES.pdf: 2215776 bytes, checksum: fc5d237ed433a12756eb499883e32497 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-11-21T12:12:51Z (GMT) No. of bitstreams: 1 JOSIANE_BRIETZKE_PORTO_TES.pdf: 2215776 bytes, checksum: fc5d237ed433a12756eb499883e32497 (MD5) / Made available in DSpace on 2018-11-21T12:20:25Z (GMT). No. of bitstreams: 1 JOSIANE_BRIETZKE_PORTO_TES.pdf: 2215776 bytes, checksum: fc5d237ed433a12756eb499883e32497 (MD5) Previous issue date: 2018-08-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Smart city is an approach to managing and coping with urban challenges in search for innovative solutions leading to better quality of life and sustainability in cities. Several initiatives have been undertaken, with a significant worldwide growth trend in the coming years. Such initiatives, however, may require non-trivial public investment, and failures resulting from them can have important consequences such as monetary loss, loss of reputation, reduced confidence and lack of public value. This research aims at setting a methodology in smart cities composed of a reference model and an assessment method from the Public Value perspective. These artifacts were evaluated based on the perception of 23 representatives of the Quadruple Helix (government, industry, university and citizens) and on the results of the applicability in practice, through an initial pilot evaluation, in the city of Nova Santa Rita. It follows Design Science as its epistemological paradigm and Design Science Research as its method, uniting theoretical and methodological rigor as well as practical utility for society. The results showed that the artifacts developed in this research can help in the design and assessment of smart cities in a gradual way, bringing together best practices considered intelligent and that allow for the expansion and/or generation of Public Value, consisting of a prescriptive scientific contribution. Among the contributions are the protocol, contingency and construction heuristics, which detail how these artifacts were rigorously designed and developed, under the Design Science paradigm, to solve the problem identified in this research. They are specific and useful knowledge, generated from this research, aimed at the practice and resolution of real problem, and can be used for future evolutions of the artifacts developed in the research and/or design of new artifacts, in different contexts and classes of problems. / Smart city corresponde a uma abordagem para gerenciamento e enfrentamento de desafios urbanos, em busca de solu??es inovadoras para melhor qualidade de vida e sustentabilidade nas cidades. Em raz?o disso, diversas iniciativas v?m sendo feitas, com tend?ncia de crescimento significativo nos pr?ximos anos, em ?mbito mundial. Entretanto, tais iniciativas podem requerer investimentos p?blicos n?o triviais e falhas podem ter consequ?ncias importantes como perda monet?ria, preju?zo em rela??o ? reputa??o, redu??o de confian?a e aus?ncia de valor p?blico para as partes interessadas. Este trabalho desenvolveu uma metodologia em smart cities, sob a perspectiva de Valor P?blico, composta por um modelo de refer?ncia e um m?todo de avalia??o, avaliados com base na percep??o de 23 representantes da Qu?drupla H?lice (governo, ind?stria, universidade e cidad?os) e nos resultados da aplicabilidade na pr?tica, por meio de uma primeira avalia??o piloto, na cidade ga?cha de Nova Santa Rita. Adota Design Science como paradigma epistemol?gico e Design Science Research como m?todo de pesquisa, unindo rigor te?rico-metodol?gico e utilidade pr?tica para a sociedade. Os resultados mostraram que os artefatos desenvolvidos nessa pesquisa podem ajudar na concep??o e na avalia??o de smart cities de um modo gradual, reunindo melhores pr?ticas consideradas inteligentes, que possibilitam amplia??o e/ou gera??o de Valor P?blico, consistindo numa contribui??o cient?fica de car?ter prescritivo. Entre as contribui??es t?m-se tamb?m o protocolo, as heur?sticas contingenciais e de constru??o, que detalham como esses artefatos foram projetados e desenvolvidos com rigor, sob o paradigma de Design Science, para a resolu??o do problema identificado nessa pesquisa. Constituem conhecimento espec?fico e ?til, gerado a partir da pesquisa, voltado ? pr?tica e ? resolu??o de um problema real, podendo ser usado para futuras evolu??es dos artefatos desenvolvidos na pesquisa e/ou no projeto de novos artefatos, em diferentes contextos e classes de problemas.

Made available in DSpace on 2014-12-17T13:57:19Z (GMT). No. of bitstreams: 1 SilenoCT.pdf: 2677839 bytes, checksum: ab606ee9a9e47606999ca5cf548141a6 (MD5) Previous issue date: 2006-12-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Natural air ventilation is the most import passive strategy to provide thermal comfort in hot and humid climates and a significant low energy strategy. However, the natural ventilated building requires more attention with the architectural design than a conventional building with air conditioning systems, and the results are less reliable. Therefore, this thesis focuses on softwares and methods to predict the natural ventilation performance from the point of view of the architect, with limited resource and knowledge of fluid mechanics. A typical prefabricated building was modelled due to its simplified geometry, low cost and occurrence at the local campus. Firstly, the study emphasized the use of computational fluid dynamics (CFD) software, to simulate the air flow outside and inside the building. A series of approaches were developed to make the simulations possible, compromising the results fidelity. Secondly, the results of CFD simulations were used as the input of an energy tool, to simulate the thermal performance under different rates of air renew. Thirdly, the results of temperature were assessed in terms of thermal comfort. Complementary simulations were carried out to detail the analyses. The results show the potentialities of these tools. However the discussions concerning the simplifications of the approaches, the limitations of the tools and the level of knowledge of the average architect are the major contribution of this study / A ventila??o natural se constitui no principal recurso passivo para obten??o do conforto t?rmico em climas quentes e ?midos, al?m de promover a redu??o do consumo energ?tico com condicionamento artificial. Entretanto, existem restri??es ao seu uso por parte dos arquitetos por n?o haver garantias de que ela possa resolver os problemas de conforto t?rmico, quando comparada aos sistemas artificiais. Nesse sentido, decidiu-se investigar formas de prever o comportamento da ventila??o natural atrav?s de ferramentas de simula??o computacional, visando auxiliar a decis?o arquitet?nica. O objeto de estudo ? o edif?cio pr?fabricado tipo galp?o devido ?s suas caracter?sticas geom?tricas e ? freq??ncia de uso na regi?o, especificamente no campus universit?rio central da UFRN. Foi utilizado um programa de din?mica de fluidos (Computational Fluid Dynamics - CFD) e um de simula??o do comportamento t?rmico e energ?tico de edifica??es (energy tool - ET). A pesquisa priorizou a discuss?o dos procedimentos necess?rios para viabilizar as an?lises da ventila??o em galp?es. Durante seu desenvolvimento, ? mostrado como o m?todo teve que ser adequado ? complexidade de sucessivas abordagens, resultando em simplifica??es e incertezas de resultados. Para exemplificar a abordagem s?o apresentados alguns resultados de simula??es. Ao final, as limita??es e potencialidades do m?todo s?o discutidas com base nas caracter?sticas dos c?digos de simula??es utilizados, das condi??es de simula??o e da representatividade dos modelos

Made available in DSpace on 2015-03-03T15:43:03Z (GMT). No. of bitstreams: 1 PauloRCS_DISSERT.pdf: 5184228 bytes, checksum: d3e31e6fed97c72238a19b42897cf9b0 (MD5) Previous issue date: 2014-05-27 / Universidade Federal do Rio Grande do Norte / In this work we obtain nickel ferrite by the combustion synthesis method whcih involves synthesising in an oven at temperatures of 750oC, 950oC and 125oC. The precursors oxidizing used were nickel nitrate, ferric as an oxidizing and reducing urea (fuel). After obtaining the mixture, the product was deagglomerated and past through a 270 mesh sieve. To assess the structure, morphology, particle size, magnetic and electrical properties of nanoparticles obtained the samples were sintered and characterized by x-ray distraction (XRD), x-ray fluorescence spectroscopy (FRX); scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometer (MAV ) and electrical permittivity. The results indicated the majority of phase inverse spinel ferrite and Hematite secondary phase nickel and nickel oxide. Through the intensity of the distraction, the average size of the crystallization peaks were half-height width which was calculated using the Scherrer equation. From observing the peaks of all the reflections, it appears that samples are crystal clear with the formation of nanoparticles. Morphologically, the nanoferritas sintered nickel pellet formation was observed with three systems of particle size below 100mn, which favored the formation of soft pellets. The average size of the grains in their micrometric scale. FRX and EDS showed qualitatively the presence of iron elements nickel and oxygen, where through quantitative data we can observe the presence of the secondary phase. The magnetic properties and the saturation magnetization and the coercive field are in accordance with the nickel, ferrite where the curve of hysteresis has aspects of a soft material. Dielectric constant values are below 10 and low tangent loss / Este trabalho descreve a obten??o de ferrita de n?quel pelo m?todo de s?ntese de combust?o, seguida pela sinteriza??o em forno, ?s temperatura de 750oC, 950oC e 1250oC. Os precursores oxidantes utilizados foram: nitratos de n?quel e ferro III como redutor, foi usada a ur?ia (combust?vel). Depois da obten??o do p?s-misturas, o produto foi desaglomerado e passado em uma peneira de mesch 270. A estrutura, a morfologia, o tamanho das part?culas e as propriedades magn?ticas e el?tricas das nanopart ?culas obtidas das amostras p?s sinterizadas foram caracterizadas por difra??o de raios-X (DRX), espectroscopia de uoresc?ncia de raios-X (FRX), microscopia eletr?nica de varredura (MEV ), espectroscopia de energia dispersiva (EDS), magnet ?metro de amostra vibrante (MAV ) e an?lise el?trica. Os resultados indicaram a fase majorit?ria do espin?lio inverso ferrita de n?quel e a fase secund?ria de hematita e ?xido de n?quel. Atrav?s da intensidade dos picos de difra??o de raios-X e da largura de meia altura no espectro, foi calculado o tamanho m?dio do cristalito pela equa??o Scherrer, observando-se os picos de todas as re ex?es, veri cando a cristalinidade das amostras, e com forma??o de nanopart?culas. Morfologicamente, para as nanoferritas de n?quel sinterizadas, observou-se a forma??o de aglomerados moles nos tr?s sistemas com part?culas de tamanho inferior a 100nm. O tamanho m?dio dos gr?os est? em escala microm?trica. Os espectros de FRX e EDS mostraram qualitativamente a presen?a dos elementos ferro, n?quel e oxig?nio. Atrav?s dos dados quantitativos, pode-se observar a presen?a da fase secund?ria. As propriedades magn?ticas, como a magnetiza??o de satura??o e o campo coercitivo, est?o de acordo com a ferrita de n?quel, em que a curva de histerese tem aspectos de um material mole. Os valores de constante diel?trica est?o abaixo de 10 e baixa tangente de perdas.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-03T20:53:53Z No. of bitstreams: 1 CarlosGomesDeMoura_TESE.pdf: 3433737 bytes, checksum: 78095bf1c8dfe0fa9a5ac309049980a1 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-04T00:22:45Z (GMT) No. of bitstreams: 1 CarlosGomesDeMoura_TESE.pdf: 3433737 bytes, checksum: 78095bf1c8dfe0fa9a5ac309049980a1 (MD5) / Made available in DSpace on 2016-02-04T00:22:45Z (GMT). No. of bitstreams: 1 CarlosGomesDeMoura_TESE.pdf: 3433737 bytes, checksum: 78095bf1c8dfe0fa9a5ac309049980a1 (MD5) Previous issue date: 2015-02-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Os metamateriais tem atra?do uma grande aten??o nas ultimas d?cadas, em decorr?ncia de suas propriedades eletromagn?ticas n?o serem encontradas na natureza. Desde que os metamateriais passaram a ser sintetizados atrav?s da inser??o de inclus?es artificialmente fabricadas num meio homog?neo especificado, facilitou ao pesquisador uma larga cole??o de par?metros independentes, como, por exemplo, as propriedades eletromagn?ticas do material. Foram realizadas investiga??es das propriedades dos ressoadores em anel e dos metamateriais. Foi apresentado um estudo das principais teorias que explicam com clareza a supercondutividade. As teorias BCS, Equa??es de London e modelo dos Dois Fluidos s?o as teorias que d?o suporte a aplica??o dos supercondutores nas antenas de microfita. Assim, esta Tese de Doutorado apresenta uma an?lise te?rica, num?rico-computacional e experimental, utilizando o formalismo de onda completa, atrav?s da aplica??o do m?todo da Linha de Transmiss?o Transversa ? LTT, aplicado no Dom?nio da Transformada de Fourier (FTD). O LTT ? um m?todo de onda completa, que tem como regra a obten??o dos campos eletromagn?ticos em termos dos componentes transversais ? estrutura. A inclus?o do patch supercondutor ? feita utilizando-se a condi??o de contorno complexa resistiva. S?o obtidos resultados da freq??ncia de resson?ncia em fun??o dos par?metros da antena. Para valida??o das an?lises foram elaborados programas computacionais na linguagem Fortran, simula??es no software comercial, sendo as curvas tra?adas no software comercial e no software Matlab, al?m de se comparar o patch convencional com o supercondutor e depois se comparar um substrato metamaterial com um convencional, juntando o substrato com o patch, verificando o que melhora em ambos os quesitos, demonstrando a utiliza??o pr?tica destas estruturas em antenas fabricadas em laborat?rio. / Metamaterials have attracted great attention in recent decades, due to their electromagnetic properties which are not found in nature. Since metamaterials are now synthesized by the insertion of artificially manufactured inclusions in a specified homogeneous medium, it became possible for the researcher to work with a wide collection of independent parameters, for example, the electromagnetic properties of the material. An investigation of the properties of ring resonators was performed as well as those of metamaterials. A study of the major theories that clearly explain superconductivity was presented. The BCS theory, London Equations and the Two-Fluid Model are theories that support the application of superconducting microstrip antennas. Therefore, this thesis presents theoretical, numerical and experimental-computational analysis using full-wave formalism, through the application of the Transverse Transmission Line ? LTT method applied in the Fourier Transform Domain (FTD). The LTT is a full wave method, which, as a rule, obtains the electromagnetic fields in terms of the transverse components of the structure. The inclusion of the superconducting patch is performed using the complex resistive boundary condition. Results of resonant frequency as a function of antenna parameters are obtained. To validate the analysis, computer programs were developed using Fortran, simulations were created using the commercial software, with curves being drawn using commercial software and MATLAB, in addition to comparing the conventional patch with the superconductor as well as comparing a metamaterial substrate with a conventional one, joining the substrate with the patch, observing what improves on both cas

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-09T23:21:32Z No. of bitstreams: 1 ElielPoggiDosSantos_DISSERT.pdf: 2107477 bytes, checksum: b83f3b889d4017245f0c0550f4569d4e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-11T21:38:50Z (GMT) No. of bitstreams: 1 ElielPoggiDosSantos_DISSERT.pdf: 2107477 bytes, checksum: b83f3b889d4017245f0c0550f4569d4e (MD5) / Made available in DSpace on 2016-03-11T21:38:50Z (GMT). No. of bitstreams: 1 ElielPoggiDosSantos_DISSERT.pdf: 2107477 bytes, checksum: b83f3b889d4017245f0c0550f4569d4e (MD5) Previous issue date: 2015-01-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Com o r?pido crescimento dos sistemas de comunica??es sem fio, estudos envolvendo absorvedores de ondas eletromagn?ticas tem despertado grande aten??o pelos pesquisadores. Suas aplica??es v?o desde sistemas indoor at? aplica??es militares. Em paralelo a esse crescimento, os estudos crescentes em superf?cies seletivas em frequ?ncia (FSS) permitem que suas propriedades de filtragem sejam aplic?veis em diversos sistemas, como em antenas refletoras, em radomes passa-faixa e em absorvedores, que ser? o foco deste trabalho. Este trabalho tem como objetivo projetar absorvedores de micro-ondas usando FSS. A metodologia consiste basicamente em duas etapas: na primeira fase, uma an?lise te?rica e num?rica das estruturas isoladas envolvidas no processo de absor??o e, na segunda fase, a an?lise das estruturas em cascata. Para a an?lise ser? utilizado o M?todo dos Circuitos Equivalentes que prev? caracter?sticas de transmiss?o da estrutura para uma onda plana com incid?ncia normal e requer recursos computacionais muito limitados quando comparado aos m?todos de an?lise de onda completa e, portanto, ? ?til para predizer com rapidez o desempenho das estruturas. Tamb?m ser? usada a Matriz de Espalhamento para modelar numericamente o cascateamento das FSS condutiva e resistiva obtendo propriedades de absor??o na faixa projetada. Os resultados experimentais usados para a an?lise s?o encontrados na literatura devido ? dificuldade de construir em pouco tempo, tendo em vista que n?o ? uma t?cnica de constru??o simples. Ser? apresentado o desenvolvimento matem?tico, pelo M?todo dos Circuitos Equivalentes, da modelagem de uma FSS com geometria do tipo dipolo cruzado e uma FSS resistiva como tamb?m o cascateamento entre as duas estruturas. A mesma configura??o ser? utilizada com uma geometria espira quadrada. Melhoramentos ser?o discutidos na conclus?o. / Considering the fact that, the use of wireless communication systems has grown too fast, investigations concerning absorbers of electromagnetic waves has called closer attention of researchers. It is applicable from indoor systems to military applications. Paralleling with this growth, some extremely relevant investigations through Frequency Selective Surfaces (FSS) allows its filter property to be applicable in several systems, for example: reflector antennas, band-pass radomes, and absorbers, which are the main objective of this work. Therefore, the main goal of this work concerns to design micro-waves absorbers through FSS. Thus, the methodology consists basically in two steps: the first step concerns a theoretical and numerical analysis of the structures involved in the process of absorption, the second step, the analysis of the cascaded structures. In order to carry out the analysis, the Equivalent Circuit Method will be used. This method provides characteristics of transmission from the structure, for a plane wave incidence and it requires an extremely limited computing resource in relation if compared to full wave analyses method. Hence, it is useful to allow fast predictions of the development of the structures. Furthermore, a spreading matrix will be used in order to cascade the conductive FSS and the resistive FSS achieving absorption characteristics in the designed band. The experimental results used for the analysis are found in the literature due to the difficulty of building soon, given that it is not a simple construction technique. To conclude, a mathematical development through the Equivalent Circuit Method of a FSS modeling with cross-dipole geometry and a resistive FSS will be presented, as well as the cascading involving the two structures. The same setting is used with a square loop geometry. Besides it, the next steps will be discussed in the conclusion.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-31T22:25:53Z No. of bitstreams: 1 CarolineGomesMoura_DISSERT.pdf: 2102873 bytes, checksum: c954d6aaea1a58ccd102a726f8bae793 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-01T23:05:31Z (GMT) No. of bitstreams: 1 CarolineGomesMoura_DISSERT.pdf: 2102873 bytes, checksum: c954d6aaea1a58ccd102a726f8bae793 (MD5) / Made available in DSpace on 2016-04-01T23:05:31Z (GMT). No. of bitstreams: 1 CarolineGomesMoura_DISSERT.pdf: 2102873 bytes, checksum: c954d6aaea1a58ccd102a726f8bae793 (MD5) Previous issue date: 2015-06-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / O PSFC (Pr0.5Sr0.5Fe1-xCuxO3-?) ? um novo ?xido misto com estrutura perovskita que vem sendo estudado para aplica??o como catodo de c?lulas a combust?vel de ?xido s?lido de temperatura intermedi?ria (600-750 ?C), principalmente devido a sua elevada condutividade i?nica e eletr?nica abaixo de 800 ?C. Neste trabalho, p?s de PSFC com duas composi??es diferentes (Pr0,5Sr0,5Fe0,8Cu0,2O3-PSFC5582 e Pr0,5Sr0,5Fe0,6Cu0,4O3-PSFC5564) foram sintetizados pelo m?todo dos citratos utilizando uma nova rota. Os p?s obtidos foram caracterizados por an?lise t?rmica (Termogravimetria e Calorimetria Diferencial Explorat?ria), e os materiais calcinados a 800, 900 e 1000 ?C por 5h foram analisados por difratometria de raios X (DRX), com refinamento Rietveld dos dados de difra??o e dilatometria. Filmes de composi??o PSFC5582 foram obtidos por serigrafia do p? calcinado a 1000 ?C. Os filmes foram depositados em substrato de c?ria dopada com gadol?nia (CGO) e sinterizados a 1050 ?C por 2h. O desempenho eletroqu?mico dos eletrodos foi avaliado por espectroscopia de imped?ncia e a interface eletrodo/eletr?lito foi observada por microscopia eletr?nica de varredura (MEV). A resist?ncia espec?fica por ?rea (ASR) foi 0,44 ?.cm? a 800 ?C, um valor pouco inferior aos reportados na literatura para catodos contendo cobalto. Os coeficientes de expans?o t?rmica (CET) do PSFC de ambas as composi??es variaram entre 13 e 15 x 10-6 ?C-1 , numa faixa de temperatura de 200 a 650 ?C, demonstrando a boa compatibilidade t?rmica destes catodos com eletr?litos de Ce0,9Gd0,1O1,95 (CET = 12 x 10-6 ?C). / The PSFC (Pr0.5Sr0.5Fe1-xCuxO3-?) is a new mixed oxide perovskite and has been studied and evaluated the cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs), mainly due to its good compatibility with the electrolyte (CGO) and its high ionic conductivity and electronic in intermediate temperature. In this work, PSFC powders with two different compositions (Pr0,5Sr0,5Fe0,8Cu0,2O3- PSFC5582 and Pr0,5Sr0,5Fe0,6Cu0,4O3-PSFC5564) were synthesized by the citrate method using a new route. The powders obtained were characterized by thermal analysis (Differential Scanning Calorimetry and Thermogravimetry), and the material calcined at 800, 900 and 1000 ?C for 5h were analyzed by X-ray diffractometry (XRD), with the Rietveld refinement of the diffraction data and dilatometry. PSFC5582 composite films were obtained by screen printing of powder calcined at 1000 ?C. The films were deposited on substrate ceria doped with gadolinia (CGO) and then sintered at 1050 ?C for 2h. The electrochemical performance of the electrodes was evaluated by impedance spectroscopy and the interface electrode/electrolyte was observed by scanning electron microscopy (SEM). The specific resistance area (ASR) was 0.44 ?.cm? at 800 ?C, slightly lower than those reported in the literature for cathodes containing cobalt. The thermal expansion coefficients of both the PSFC compositions were obtained and varied between 13 and 15 x 10-6 ?C-1 , in a temperature range of 200 to 650 ?C, demonstrating the good thermal compatibility of cathodes with Ce0,9Gd0,1O1,95 electrolytes (CET = 12 x 10-6 ?C).

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-22T23:30:25Z No. of bitstreams: 1 GiscelyCostaMedeirosDaSilva_DISSERT.pdf: 1017549 bytes, checksum: 04e0d02115ad6df5d87ea2fbcb1a637f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-22T23:57:52Z (GMT) No. of bitstreams: 1 GiscelyCostaMedeirosDaSilva_DISSERT.pdf: 1017549 bytes, checksum: 04e0d02115ad6df5d87ea2fbcb1a637f (MD5) / Made available in DSpace on 2016-04-22T23:57:52Z (GMT). No. of bitstreams: 1 GiscelyCostaMedeirosDaSilva_DISSERT.pdf: 1017549 bytes, checksum: 04e0d02115ad6df5d87ea2fbcb1a637f (MD5) Previous issue date: 2015-03-30 / A partir de um caso cl?nico cuja queixa era uma severa ?indisciplina escolar?, este trabalho interrogou quando a indisciplina pode ser um sintoma. Para responder a quest?o analisamos o conceito de sintoma na perspectiva freudo-lacaneana, e suas articula??es com o tema da ?indisciplina escolar?. Utilizou-se o m?todo te?rico-cl?nico, no qual a constru??o do caso dialoga com os textos psicanal?ticos reatualizando as quest?es sobre o tema. Empreendemos uma an?lise hist?rica da constru??o do mecanismo disciplinar atrav?s das obras de Foucault (1987; 1996), Deleuze (1988; 1992) e comentadores que apontou o car?ter datado e n?o natural dessa produ??o discursiva nomeada ?indisciplina escolar?, revelando que a queixa de indisciplina nasce de um discurso social que imp?e a ideia de que o aprender depende da disciplina. No entanto, esse ide?rio possui uma fenda, pois algo sempre escapa ao disciplinamento. A resposta do social ao que escapa constitui a queixa de indisciplina, que pode ser tomada como um sintoma social. A cada crian?a cabe encontrar sua resposta frente a esse discurso, e a mesma define o car?ter sintom?tico, ou n?o, da mesma. Percorremos o conceito de sintoma e seus desdobramentos na cl?nica com a crian?a nos ensinos de Freud e Lacan. A leitura de Freud mostrou que o sintoma ? o resultado de um trabalho ps?quico que substitui uma representa??o recalcada e ligada a uma satisfa??o sexual insuport?vel, constituindo uma solu??o para que a crian?a possa lidar com a castra??o e com as interdi??es impostas pelo social. A releitura da obra freudiana empreendida por Lacan coloca o assento no car?ter de trabalho ps?quico empreendido pelo falante com o seu sintoma, na medida em que lhe permite fazer la?o com o social. Analisar, a cada caso, a posi??o ocupada pelo sujeito frente ? queixa de indisciplina permite abrir as vias para o trabalho com a mesma. Se a indisciplina ? a resposta do sujeito frente ao Outro social, a partir da psican?lise trata-se de ofertar uma escuta que permita resignificar essa resposta. Elucidar o car?ter sintom?tico, ou n?o, das atitudes consideradas indisciplinadas convoca ? an?lise da singularidade implicada na resposta de cada crian?a, a sua subjetividade. / From a clinical case reporting a severe ? scholarship indiscipline?, this work questioned how the indiscipline can be a symptom . To answer the question, it was analyzed the symptom concept from the Freudian - lacaneana perspective and theirs connections with ? scholarship indiscipline? subject . The research used a theoretical and clinical method , to show the connection between the case development and the psychoanalytic publications reviewing questions on the subject . It was undertook a historical analysis of the construction of disciplinary mechanism through the works of Foucault (1987, 1996), Deleuze (1988; 1992) and commentators. This historical analysis showed a dated and unnatural character of this discursive production named ? scholarship indiscipline?, revealing the indiscipline complaint comes from a social speech that imposes the idea that learn ing depends on the discipline. However , this idea type has a flaw , because always something escapes disciplining . The social answer to the escape is the complaint of indiscipline, which can be taken as a social symptom . Each child should find an answer to this speech and define the symptomatic character , or not , from itself . It was evaluated the symptom and its consequences in the clinic with the child in the Freud and Lacan teachings . The Freud view showed the symptom is the answer to a psychic work , replacing a repressed representation linked to an unbearable sexual dis satisfaction , providing a solution for the child to deal with castration and with the imposed social restrictions . A review of Freud's work undertaken by Lacan emphasizes the psycholog ical work characteristics undertaken by the speaker with its symptom by the link with the social aspect. To analyze, in each case, the position occupied by the patient of a complaint against the indiscipline can open the way to work with it. If the discipl ine is the answer of the subject towards the Other social, from psychoanalysis it is offering a help that allows reframe this response. Elucidating the symptomatic character, or not, from attitudes considered undisciplined, calls for the analysis of unique ness involved in the response of each child, their subjectivity.