Made available in DSpace on 2016-06-02T19:55:32Z (GMT). No. of bitstreams: 1 4381.pdf: 2748711 bytes, checksum: 4ba9831d0665b24b6f48f775d30927d2 (MD5) Previous issue date: 2012-04-13 / Universidade Federal de Minas Gerais / The minimization of the emissions of nitrogen oxides (NOx) is a subject of crucial interest, since them cause serious environmental problems which affect human health, vegetation and fauna. With the purpose to abate NOx, processes involving their catalytic reduction show strong potential. In the case of the reduction of NO with CO a meaningful advantage arises, once both pollutants are removed simultaneously. In order to obtain efficient and stable catalysts for this reaction, many studies have been done with the aim to improve the catalytic activity by achieving a better favorable metal-support interaction to the occurrence of the reaction and a better distribution of the active phases on the support. In this context, the objective of this study was to prepare Cu, Fe and Co based catalysts supported on TiO2, CeO2 and ZrO2 to be applied in the abatement of NO with CO. The addition of the precursors of the active phases was made during the synthesis of the support via the sol-gel method (in situ addition). Furthermore, catalysts with the same composition were prepared by conventional methods. Results from the N2 adsorption/desorption measurements show that the sol-gel method was efficient to prepare supports with improved textural properties. H2-TPR and UVVIS-DRS data evidenced the presence of Cu, Fe or Co oxides in the respective catalysts, which mostly did not show characteristic X-ray diffraction peaks of those oxide phases, suggesting their high dispersion on the supports. In general, results of the reduction of NO to N2 with CO revealed that the catalysts prepared via sol-gel are as active as those prepared by conventional routes, which demonstrate the great potential of the catalysts preparation via the sol-gel in situ procedure, which diminishes the number of the synthesis steps saving time and energy. In general, among the studied supports, ceria presented a more favorable metal-support interaction. In the presence of O2, SO2 and water steam, catalysts 6,5Cu/CeP, 5,5CuZrSG and 8,4Fe/TiC showed no significant changes in their activity and selectivity, indicating that they present high stability to be used under the severe conditions of real processes. / A minimização das emissões de óxidos de nitrogênio (NOx) é assunto de interesse crucial, pois geram graves problemas ambientais que afetam à saúde humana, à flora e à fauna. Para abater os NOx, processos envolvendo à sua redução catalítica apresentam forte potencial. No caso da redução catalítica de NO com CO, tem-se a vantagem adicional de minimizar as emissões de ambos poluentes. Para a obtenção de catalisadores eficientes e estáveis para essa reação, muitos estudos têm sido desenvolvidos no sentido de aumentar a atividade por meio de uma interação metalsuporte mais favorável ao processo reativo e de se conseguir uma melhor distribuição da fase ativa no suporte. Nesse contexto, o objetivo do presente estudo foi preparar catalisadores para a redução de NO com CO à base de óxido de Cu, Fe ou Co, suportados em TiO2, CeO2 ou ZrO2, com a adição do precursor da fase ativa durante a preparação do suporte via processo sol-gel (adição in situ). Além disso, catalisadores de mesma composição foram preparados por rotas convencionais. Resultados de medidas de adsorção/dessorção de N2 dos suportes mostram que o método sol-gel utilizado é mais eficiente no preparo de suportes com propriedades texturais melhoradas. Análises de RTP-H2 e ERD-UVVIS evidenciaram a presença dos óxidos de Cu, Fe ou Co em todos os catalisadores, os quais, em sua maioria, não apresentaram picos de difração de raios X característicos dessas fases, o que sugeriu sua alta dispersão no suporte. Em geral, os resultados da redução de NO a N2 com CO mostraram que os catalisadores preparados pelo método sol-gel in situ são tão ativos quanto os catalisadores preparados por métodos convencionais, o que demonstra o forte potencial desse procedimento, que resulta no uso de um número menor de etapas na preparação do catalisador, com a consequente economia de tempo e energia. De maneira geral, dentre os suportes estudados a céria mostrou uma relação metal-suporte mais favorável ao processo de óxidoredução. Os catalisadores 6,5Cu/CeP, 5,5Cu-ZrSG e 8,4Fe/TiC, na presença de O2, SO2 e vapor de água não apresentaram alteração significativa da sua atividade e seletividade, mostrando uma alta estabilidade para atuar sob as drásticas condições dos processos reais.

This dissertation is focus¡qCuo Zhan CuiNing¡r¡mShuang Xiong Meng¡n¡qPoXiaoShief¡rThose three story¡¦s text are used¡uShi Wu Guan¡v for subject matter, differentiate narrate model, personage molding and idea of theme three parts for base to discuss.And use a method of ¡§conclusion to collect¡¨ compare to analyse. In the same time, By way of this theme¡¦s to compare, let us to clarify some question in tradition and evolve. In the narrate model,¡qCuo Zhan CuiNing¡r¡mShuang Xiong Meng¡nuse overtop for outside field of vision in this story, but¡qPoXiaoShief¡rjust use Lao San¡¦s observe for this point of view. Besides¡qCuo Zhan CuiNing¡ruse different to mess in a narrator, let this theme pervade dense deliver a sermon implication. But ¡mShuang Xiong Meng¡nand¡qPoXiaoShief¡rare use the same narrator give rise sympathetic emotions, let two texts full more sympathetic.¡qPoXiaoShief¡r use flashback statement technique let story copious. Unique statement and slow statement step is the characteristic of this story. In the main from ¡qCuo Zhan CuiNing¡rto¡qPoXiaoShief¡r,the narrate model also from single to various. In the personage model,¡qCuo Zhan CuiNing¡rin personage model is major match the story plot, belong E.M. Forster mean¡uflat character¡v. Zhu Su Chen form looks and character to describe, mold role to different style, but he ignore the personage character, let¡mShuang Xiong Meng¡nthis story¡¦s personage describe to perfection, can not call perfect¡uround character¡v. Zhu Xi Ning major inherent to describe personage character. From E.M. Forster theory to view, ¡qPoXiaoShief¡r we can say almost ¡uround character¡v. Make a comprehensive to those three stories we can found from exterior describe change to inherent describe. In the subject thinking, ¡qCuo Zhan CuiNing¡r most clear to see is¡uspeak and act cautiously life philosophy¡v and¡utradition of retribution for sin¡v. Except an official related topic are three texts highlight.¡qPoXiaoShief¡rexcept had ¡uShi Wu Guan¡vstory, and enter into Lao San¡¦s plot, open another topic for concerned humanity, and the same time confer center of gravity from people face on environment to people this topic. This series of¡qCuo Zhan CuiNing¡r is the prototype of statement works, in the change course the theme thinking from reflect live actual state to concerned humanity and people.

The perovskite structure has an incredible versatility that results in myriad compounds with varied and eccentric behaviors. Perovskite oxides have been extensively studied and used for over 60 years. In order to expand on our already thorough knowledge of these compounds, it is necessary to use modern and creative experimental techniques. High-pressure synthesis and high oxygen-gas pressure annealing techniques are used to synthesize oxygen stoichiometric RNiO₃ (R = lanthanide). The particularly rich phase diagram of this compound allows for the study of the crossover from localized to itinerant electronic behavior and from an enhanced Pauli to a Curie-Weiss law paramagnetism. Single crystals of RFeO₃ are grown in order to analyze the spin canting in these antiferromagnetic samples. The size of the rare earth-cation is used to tune the magnitude of octahedral-tilt distortions. This tuning allows distinguishing between the two possible drivers for spin canting and weak ferromagnetism in these compounds, the octahedral-tilt-dependent single-ion anisotropy and the octahedral-tilt-independent Dzyaloshinskii-Moriya interaction. Although it is a fluoride compound, KCuF₃ has been used as an analogue to transition-metal oxide perovskites such as LaMnO₃ because of the similarity of their orbital ordering. Through the use of high-temperature neutron diffraction, it is shown that the orbital ordering and Jahn-Teller distortion in this compound are not lifted at the predicted temperature. Another mechanism for orbital ordering is identified. La₂[subscript-x] Sr [subscript x] CuO₄ has long been of interest as the progenitor system of the highTc superconductors. Despite having an exceedingly well-studied phase diagram in the over-doped region of its superconducting dome, little is known about this system in the region x > 0.3 because of the difficulty of synthesizing fully oxygen-stoichiometric samples. With high-oxygen-gas-pressure annealing and high-pressure synthesis, the completion of the phase diagram up to x = 1.0 is attempted. Finally, like many iridates, post-Perovskite CaIrO₃ exhibits a very strong spinorbit coupling of its 5d electrons. Because its magnetism is very weak, traditional methods to measure the magnitude of its orbital moment and spin-orbit coupling, such as neutron powder diffraction, are not viable. In order to address this issue, direct measurement of the orbital moments was conducted by using x-ray absorption spectroscopy and x-ray magnetic circular dichroism techniques. / text

Ce travail concerne le développement de procédés d'intégration de couches énergétiques de type thermite (constituées d'un oxyde et d'un métal, généralement Al) dans les microsystèmes pour la réalisation de microsources de température pour des applications militaires et civiles (aérospatiale, automobile). Après avoir sélectionné le matériau à formuler, la thermite Al/CuO, notre travail s'est organisé selon deux axes : (1) élaborer et optimiser des technologies de dépôt d'Al/CuO qui permettent de maîtriser autant que possible les caractéristiques stSchiométriques et géométriques à l'échelle nanométrique du matériau déposé pour en contrôler la cinétique et en optimiser la chaleur de décomposition. (2) intégrer la nanothermite dans un micro-initiateur pour explorer les applications de micro-amorçage. Deux procédés de dépôt simples et reproductibles ont été développés: un procédé fondé sur l'oxydation thermique du Cu qui permet la formation de nanofils pour des surfaces inférieures à 1 mm2 et un procédé fondé sur la pulvérisation cathodique réactive qui permet l'obtention d'empilements successifs de nanofeuillets d'Al/CuO d'épaisseur réglable. L'intégration sur plateforme chauffante micro-usinée de ce matériau permet la libération contrôlée de chaleur (1,2 kJ/g) pour une température de réaction de 740 K. La nanothermite, en tant qu'initiateur, permet la mise à feu de propergol au contact et jusqu'à une distance de 270 µm. Nous discutons ensuite des perspectives ouvertes pour réaliser, au moyen de procédés collectifs, des micro-initiateurs pyrotechniques et de l'importance d'outils de modélisation multi-échelle pour aider à la compréhension de la réactivité du matériau.

Les matériaux énergétiques sont une classe de matériaux capables de libérer de l'énergie dans les conditions d'utilisations. Notre laboratoire a été le premier dans les années 1995 à proposer l'intégration de matériaux énergétiques dans des micro dispositifs ce qui a engagé un important processus d'innovations dans le choix des matériaux nécessitant une compatibilité avec les technologies microélectroniques et dans leur mise en œuvre pour des usages embarqués divers : micro allumeurs, airbags, actionnements pneumatiques ou fluidiques, conversion thermo électriques, ... Cette thèse visent la mise au point de nouvelles générations de matériaux susceptibles d'être intégrés sur des micro dispositifs pour la réalisation de systèmes d'allumages miniaturisés. Mais le choix d'un matériau intégrable est un problème complexe, d'une part parce qu'il doit pouvoir etre déposé dans le processus de fabrication du micro dispositif support et d'autre part parce qu'il doit permettre d'actionner dans de bonnes conditions d'autres matériaux énergétiques plus traditionnels. Parmi les matériaux énergétiques émergents, les nanothermites engendrent un grand intérêt grâce à leur forte capacité énergétique et leurs propriétés réactives " à la carte " et aussi, en ce qui nous concerne, car elles mettent en œuvre des composés métaux et oxydes métalliques compatibles avec les composants microélectroniques et les technologies MEMS. C'est dans ce contexte-là que notre équipe de recherche a proposé l'élaboration et l'intégration de multicouches Al/CuO par PVD. L'empilement par PVD de nano-couches alternées d'aluminium et d'oxyde de cuivre offre de nombreux avantages comparés à l'élaboration de nano-poudres. Chaque nano-couche déposée peut être contrôlée précisément en épaisseur (de quelques nm jusqu'à plusieurs centaines de nm). Et, le nombre de couches et la stœchiométrie oxydant/réducteur peuvent être modifiés pour adapter la réactivité du matériau en fonction du besoin. Mon travail de thèse a permis l'étude expérimentalement des nano-thermites de type multicouches Al/CuO déposées par pulvérisation cathodique. En particulier, sur des dépôts PVD de multicouches Al/CuO d'épaisseurs comprise entre 25nm et 500nm, nous avons caractérisé finement la morphologie de couches Al et CuO et de leur interface. Nous avons contribué à évaluer expérimentalement l'influence de la stœchiométrie et de l'épaisseur des couches sur les caractéristiques de réaction à savoir la vitesse de combustion et l'énergie de décomposition appelée Entalphie. Enfin, nous avons étudié le rôle des interfaces dans le processus de réaction. Pour ce faire différentes thermites multicouches Al/CuO avec différentes stœchiométries et épaisseurs ont été déposées. Les analyses structurelles, morphologiques et chimiques ont été réalisées au LAAS et au CIRIMAT par différentes techniques d'analyses telles que XRD, HR-TEM, XPS et STEM-EDX. Les chaleurs de réaction et la vitesse de combustion ont été examinées par DSC et par camera rapide. Enfin nous avons intégré des multicouches Al/CuO dans un microsystème d'allumage sécurisé pour une application de propulsion solide dans le cadre d'un contrat industriel avec ROXEL (Contrat PEA APTE).

Made available in DSpace on 2016-06-02T19:56:55Z (GMT). No. of bitstreams: 1 6143.pdf: 2289936 bytes, checksum: dcf4b81e424bb217ab83315f71624407 (MD5) Previous issue date: 2014-03-31 / Universidade Federal de Sao Carlos / NO, NO2 and N2O nitrogen oxides, named NOx, strongly contribute to the air pollution and to minimize their emissions are used catalytic processes. The catalytic reduction of NO with CO has the advantage to simultaneously abate both pollutants. For that reaction are used noble metal based catalysts, but due to their scarcity and high cost, many research have been established to their substitution by transition metal oxides, which have high potential to catalyze that reaction. Those new catalysts beside to be active to the NO reduction with CO, they must be highly selective to N2 formation, stable at high temperatures and especially resistant to the presence of the interfering compounds (O2, SO2 and H2O). In this work were prepared Fe2O3, CuO or Fe2O3-CuO catalysts supported on y-Al2O3, ZrO2 or ZrO2/y-Al2O3. The supports were prepared via synthesis sol-gel using metallics alkoxides as precursors and the active phases introduced by impregnation of Fe(III) or Cu(II) nitrates. The obtained solids were characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption measurements, hydrogen temperature programmed reduction (H2-TPR) and their activity evaluated by the reduction of NO with CO between 100 to 600°C in the presence or absence of SO2, O2 and H2O. The synthesis via sol-gel resulted in y-Al2O3 and ZrO2/y-Al2O3 supports with high specific surface area that allowed adequately distribute the CuO and Fe2O3 oxides, which did not present X ray diffraction peaks. The catalysts were considerably active in the reduction of NO with CO, with the bimetallic ones being slightly more selective to N2 formation. In the presence of SO2, the Fe2O3/y- Al2O3 and Fe2O3/ZrO2/y-Al2O3 catalysts showed more catalytic stability. The presence of O2 led to a significantly NO conversion loss due to the direct CO oxidation by O2. In the presence of H2O or of all the interfering compounds, the NO conversion loss was more pronounced, except the CuO/ZrO2, that was more resistant in the presence of H2O. / Os óxidos de nitrogênio NO, N2O e NO2, denominados de NOx, são fortes causadores da poluição atmosférica e, para minimizar suas emissões utilizam-se processos catalíticos. A redução de NO com CO tem a vantagem de abater simultaneamente ambos poluentes. Nessa reação, são utilizados catalisadores à base de metais nobres, mas, a sua escassez e alto custo têm direcionado pesquisas para a sua substituição por óxidos de metais de transição, os que mostram potencial para essa reação. Além de ativos, esses catalisadores devem ser seletivos à produção de N2, estáveis em altas temperaturas e sobre tudo estáveis na presença dos interferentes O2, H2O e SO2. Neste trabalho foram preparados catalisadores de Fe2O3, CuO ou Fe2O3-CuO suportados em y-Al2O3, ZrO2 ou ZrO2/y-Al2O3. Os suportes foram preparados via sol-gel, utilizando alcóxidos metálicos como precursores e, a introdução das fases ativas, efetuada via impregnação utilizando nitratos de Fe(III) ou Cu(II). Os suportes e catalisadores foram caracterizados por difração de raios X (DRX), fisissorsão de nitrogênio, redução com hidrogênio à temperatura programada (RTP-H2) e a sua atividade avaliada através da redução de NO a N2 com CO, entre 100 e 600°C, na ausência ou presença de interferentes. A síntese sol-gel resultou em suportes y- Al2O3 e ZrO2/y-Al2O3 de alta área superficial, permitindo uma adequada distribuição de CuO e Fe2O3, os que não apresentaram picos de DRX. Os catalisadores foram bastante ativos na redução de NO a N2, com os bimetálicos sendo ligeiramente mais seletivos à formação de N2. Na presença de SO2 os catalisadores Fe2O3/y-Al2O3 e Fe2O3/ZrO2/y-Al2O3 foram mais estáveis. A presença de O2 provocou significativa queda na conversão de NO, favorecendo a oxidação direta do CO. Na presença de H2O ou de todos os interferentes simultaneamente, a queda da conversão de NO a N2 sobre todos os catalisadores analisados foi total, com exceção ao catalisador de CuO/ZrO2, que foi mais resistente na presença de vapor de água.

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-20T12:46:23Z No. of bitstreams: 1 arquivototal.pdf: 6514592 bytes, checksum: 18bfeb35fc0829b5f73b8b000b03a14d (MD5) / Made available in DSpace on 2017-06-20T12:46:23Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 6514592 bytes, checksum: 18bfeb35fc0829b5f73b8b000b03a14d (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Clay minerals have attracted significant attention for use in heterogeneous catalysis, showing high versatility and low cost, besides their structural properties allow modifications by activation in order to obtain active catalysts. Otherwise, metallic oxides, like ZnO, CuO and CeO2, are promising materials in the catalysis for the biodiesel synthesis, whether pure or in mixtures and supported materials. Due to the search for catalysts that facilitate the separation and purification processes of the final productof transesterification, this research aimed to study the viability of ZnO, CuO and CeO2 synthesis and their simultaneous deposition on bentonite (natural and on its acid form). Moreover, the formation of ZnO/Bentonite hybrids was also evaluated. The microwave assisted hydrothermal/solvothermal method was employed to obtain the catalysts. A factorial design 23 was employed to evaluate the different experimental conditions for the synthesis of hybrids. The catalysts were characterized by X-ray diffraction, N2 adsorption, field emission scanning electronic microscopy, transmission electronic microscopy, thermogravimetry, X-ray fluorescence and infrared spectroscopy. Biodiesel synthesis was carried out using the Parr reactor, employing ethyl alcohol and soy bean. For the tests using the hybrids, the influence of the catalyst on biodiesel production was evaluated using a factorial design 22. The products of catalytic tests were characterized by kinematic viscosity, 13C and 1H nuclear magnetic resonance spectroscopy (NMR) and gas chromatography (GC).The results indicated that the natural bentonite is a good support for the formation of the catalysts obtained by microwave assisted hydrothermal/solvothermal method, showing effective whether for the formation of impregnated bentoniteon metallic oxides or hybrids synthesis. Among the metallic oxides, ZnO showed the highest activity. The factorial design allowed to identify that the pH factor for the catalysts and the temperature one for the biodiesel were the parameters that had more influence in the synthesis. The use of ZnO as active phase for the formation of the impregnated bentonite catalysts and hybrids increases the catalytic activity for transesterification reaction, achieving more than 73% yield after 4 hours of reaction and adding value to the bentonite. / Os argilominerais têm despertado interesse para utilização na catálise heterogênea por apresentar alta versatilidade, baixo custo além de possuir propriedades estruturais que possibilitam modificações por ativação para produzir catalisadores ativos. Já os óxidos metálicos, como o ZnO, CuO e CeO2, são materiais que vêm apresentando resultados promissores na catálise para síntese do biodiesel, tanto na forma pura como em mistura de diferentes óxidos ou mesmo como suportes. Devido à busca por catalisadores que facilitem o processo de separação e purificação do produto final da transesterificação, esta pesquisa propôs estudar a viabilidade da síntese do ZnO, CuO e CeO2 e a deposição simultânea em bentonita na sua forma natural e acidificada. Além disso, foi avaliada a formação de híbridos de ZnO/Bentonita. Para produção dos catalisadores foi utilizado o método de síntese hidrotérmico/solvotérmico assistido por micro-ondas. Na síntese dos híbridos, foi utilizado um planejamento fatorial 23 para avaliar as diferentes condições experimentais. Os catalisadores foram caracterizados por difração de raio-X, adsorção de nitrogênio, microscopia eletrônica de varredura com emissão de campo e microscopia eletrônica de transmissão, termogravimetria, fluorescência de raio-X e espectroscopia de infravermelho. O biodiesel foi obtido a partir do óleo de soja utilizando reator Parr, pela rota etílica. Nos testes com os híbridos, a influência dos catalisadores na produção de biodiesel foi avaliada utilizando um planejamento fatorial 22. Os produtos dos testes catalíticos foram caracterizados por viscosidade cinemática, ressonância magnética nuclear (RMN) de 13C e 1H e cromatografia gasosa (CG). O estudo possíbilitou perceber que a bentonita precursora natural é um bom suporte para a formação dos catalisadores pelo método hidro/solvotérmico assistido por micro-ondas, com eficácia tanto na produção de bentonita impregnada com óxidos metálicos, como na formação dos híbridos. Entre os óxidos metálicos, o ZnO demonstrou maior atividade. Os estudos estatísticos das condições de síntese permitiram identificar que o fator pH para os catalisadores e o fator temperatura para o biodiesel foram os de maior interferência na síntese. A utilização do ZnO como fase ativa para a formação dos catalisadores de bentonita impregnada e híbridos aumenta o efeito catalítico na reação de transesterificação, conduzindo a conversões superiores a 73% após 4 h de reação e agrega valor à bentonita.

Made available in DSpace on 2014-12-17T14:13:57Z (GMT). No. of bitstreams: 1 TertulianoAN.pdf: 232411 bytes, checksum: a161cb11c2dc4f0938a8a590c218ab3d (MD5) Previous issue date: 2005-04-12 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Enterocutaneous fistulas are associated with prolonged hospital stay, high morbidity/mortality, and increase in hospital costs. This study aims to describe the use of a vacuum system and normal oral diet in dealing with this problem. Methods: Seventy-four consecutive patients with recent and defined external postoperative fistulas were analyzed. Abdominal imaging was used to exclude abscess and distal obstruction. The fistula tract was sealed with Foley catheter, connected to a negative pressure flask, changed daily for 5, 10 or 15 days, as necessary. Normal oral diet was permitted. Results: No patient died. Serum albumin and transferrin showed significantly higher levels at the end of treatment than at the beginning. The moderate and low-output fistulas had the best results (97% closed). Forty-eight (65%) fistulas closed after five days, 16(22%) after 10 days and 4(5%) after 15 days. Treatment failed in 6(8%) patients, who subsequently underwent surgery. Only one patient with low-output did not close her fistula. The cost of the treatment was US$ 41.75/day and it was considered cost effective. Conclusions: The vacuum system demonstrated good results in the treatment of fistulas. It included simplicity, low cost, short hospital stay, absence of skin breakdown, normal eating, good nutrition and activity patterns / As f?stulas enterocut?neas s?o associadas com hospitaliza??o prolongada, alta morbidez e mortalidade, e aumento dos custos hospitalares. Foi realizado estudo com o objetivo de analisar o uso de um sistema a v?cuo e dieta oral normal para o tratamento dessas f?stulas. M?todos: Foram analisados setenta e quatro pacientes consecutivos portadores de f?stulas enterocut?neas p?s-operat?rias, recentes e bem definidas. Exames abdominais por imagem foram usados para excluir abscesso e obstru??o intestinal distal. O trajeto fistuloso foi fechado com sonda de Foley conectada a um frasco de press?o negativa, que era trocado diariamente por 5, 10 ou 15 dias, conforme necess?rio. Foi permitida dieta oral normal a todos os pacientes. Resultados: Nenhum paciente morreu. Os n?veis de albumina e transferrina s?rica mostraram-se significativamente mais elevados no final do tratamento, quanto comparado com seu in?cio. As fstulas de d?bitos baixo e moderado atingiram os melhores resultados e 97% delas fecharam. Quarenta e oito (65%) f?stulas fecharam ap?s 5 dias, 16(22%) ap?s 10 dias e 4(5%) ap?s 15 dias de tratamento. O sistema falhou em 6(8%) pacientes, que subseq?entemente foram submetidos a interven??o cir?rgica. Apenas em um paciente com fi?stula de baixo d?bito n?o se conseguiu resultado satisfat?rio. O tratamento teve o custo di?rio de R$ 108,55 e foi considerado baixo e efetivo. Conclus?es: O sistema a v?cuo utilizado demonstrou bons resultados no tratamento das f?stulas. Caracterizou-se por simplicidade na execu??o, baixo custo, curto per?odo de hospitaliza??o, aus?ncia de les?es cut?neas, dieta normal, bom estado nutricional, mobilidade e atividades normais dos pacientes

Made available in DSpace on 2014-12-17T15:15:04Z (GMT). No. of bitstreams: 1 FranciscoES_Fis.pdf: 479617 bytes, checksum: 973534294f52a9d1981e10ed49800d56 (MD5) Previous issue date: 2005-07-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Many astronomical observations in the last few years are strongly suggesting that the current Universe is spatially flat and dominated by an exotic form of energy. This unknown energy density accelerates the universe expansion and corresponds to around 70% of its total density being usually called Dark Energy or Quintessence. One of the candidates to dark energy is the so-called cosmological constant (Λ) which is usually interpreted as the vacuum energy density. However, in order to remove the discrepancy between the expected and observed values for the vacuum energy density some current models assume that the vacuum energy is continuously decaying due to its possible coupling with the others matter fields existing in the Cosmos. In this dissertation, starting from concepts and basis of General Relativity Theory, we study the Cosmic Microwave Background Radiation with emphasis on the anisotropies or temperature fluctuations which are one of the oldest relic of the observed Universe. The anisotropies are deduced by integrating the Boltzmann equation in order to explain qualitatively the generation and c1assification of the fluctuations. In the following we construct explicitly the angular power spectrum of anisotropies for cosmologies with cosmological constant (ΛCDM) and a decaying vacuum energy density (Λ(t)CDM). Finally, with basis on the quadrupole moment measured by the WMAP experiment, we estimate the decaying rates of the vacuum energy density in matter and in radiation for a smoothly and non-smoothly decaying vacuum / Muitas observa??es astron?micas feitas nos ?ltimos anos sugerem fortemente que o universo ? espacialmente plano e dominado por uma forma de energia ex?tica. Esta densidade de energia desconhecida acelera a expans?o do universo e corresponde a cerca de 70% da densidade total de energia sendo chamada de Energia Escura ou Quintess?ncia. Um dos candidatos a energia escura, ? a chamada constante cosmol?gica (Λ) que ? usualmente interpretada como a densidade de energia do v?cuo. Contudo, para remover a discrep?ncia entre os valores esperado e observado para a densidade de energia do v?cuo, alguns modelos atuais assumem que a energia do v?cuo decai continuamente devido a seu poss?vel acoplamento com os outros campos materiais do cosmos. Nesta disserta??o, partindo dos conceitos e fundamentos da teoria da relatividade geral, estudamos a radia??o c?smica de fundo com ?nfase nas anisotropias ou flutua??es em sua temperatura que servem de base observacional para o modelo do Big Bang e ? uma das rel?quias mais antigas do universo. As anisotropias s?o deduzidas a partir da integra??o da equa??o de Boltzrnann, que fazemos em primeira ordem para explicar qualitativamente a gera??o e c1assifica??o destas flutua??es. Em seguida construimos o espectro angular de pot?ncia das anisotropias e deduzimos sua forma expl?cita em grandes escalas para o modelo com constante cosmol?gica (ACDM) e para um modelo com decaimento do v?cuo (Λ(t)CDM). Com base no momento de quadrup?lo medido pelo experimento do WMAP; estimamos as raz?es de decaimento da densidade de energia do v?cuo em mat?ria e em radia??o tanto no decaimento homog?neo como no n?o- homog?neo

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24615号 / 工博第5121号 / 新制||工||1979(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 邑瀬 邦明, 教授 杉村 博之, 教授 宇田 哲也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM