Dentro do conjunto de aspectos relacionados à elaboração de projetos em estruturas de aço e mistas de aço e concreto, destaca-se como de grande importância e interesse, para fins de dimensionamento, a consideração de elementos estruturais submetidos a temperaturas elevadas. Nesse sentido, o presente trabalho tem como objetivo principal propor a construção de modelos numéricos tridimensionais de pilares de aço pertencentes a sistemas estruturais correntes da construção civil, para análise em situação de incêndio, com vistas a simular numericamente a evolução dos níveis de temperatura ao longo do tempo com posterior acoplamento termoestrutural. Considera-se uma análise paramétrica com vista a variar as restrições axiais totais e parciais da barra, no referente aos deslocamentos axiais, contemplando desde a situação de extremidade livre até a restrição completa em resposta à consideração de apoio do tipo fixo, por exemplo. Os resultados numéricos são comparados a ensaios experimentais de outros autores, bem como com outros trabalhos numéricos já publicados. São obtidas respostas de deslocamentos axiais e laterais do modelo termoestrutural para diversas disposições de paredes em relação ao perfil, bem como gráficos do acréscimo de força axial introduzido no sistema pela restrição axial. Os estudos aqui realizados poderão servir como base para novas pesquisas tanto no campo numérico quanto experimental, assim como para futuras revisões da ABNT NBR 14323:1999, buscando contemplar situações de interesse não abordadas neste documento normativo. Os resultados da pesquisa apontam que a consideração do campo térmico com a inclusão da alvenaria no modelo termoestrutural pode melhorar consideravelmente o desempenho do elemento estrutural em situação de incêndio. / Within the set of aspects related to the development of researches in steel and composite steel and concrete structures, stands out with great importance and interest, aiming to dimension, the consideration of structural elements subjected to high temperatures. In this way, the present work has as main objective to propose the construction of three-dimensional numerical models of steel columns that belong to current structural systems of civil construction, for examination in fire situation, aiming to simulate numerically the evolution of temperature levels throughout of time with later termoestrutural coupling. It will be considered a parametric analysis in order to vary the total and partial axial restraint in respect to the axial displacements, since the free end situation until the complete restriction in response to the consideration of support for the fixed type, for example. The numerical results are compared to experimental tests made by other authors, as well as with others numerical works already published. Answers are obtained from axial and lateral displacements of the thermo structural model to many displacement of wall related to the profile, also charts of adding axial force introduced into the system by the axial restraint. The results of the current research could serve as a basis for further research in both the numerical field or experimental, also for future revisions of ABNT NBR 14323:1999, aiming to see situations of interest not studied in the same normative document. The results of this work show that consideration of thermal field with the inclusion of masonry in the thermo structural model can, significantly, improve the performance of the structural element in a fire situation.

Temporal variations of Earth\'s magnetic field provide a great range of geophysical information about the dynamics at different layers of the Earth. Since it is a planetary field, regional and global aspects can be explored, depending on the timescale of variations. In this thesis, the geomagnetic field variations for the last two millennia were investigated. For that, some improvement on the methods to recover the ancient magnetic field intensity from archeological material were done, new data was acquired and a critical assessment of the global archaeomagnetic database was performed. Two methodological advances are reported, comprising: i) the correction for microwave method of the cooling rate effect, which is associated to the difference between the cooling times during the manufactory of the material and that of the heating steps during the archaeointensity experiment; (ii) a test for thermoremanent anisotropy correction from the arithmetic mean of six orthogonal samples. The temporal variation of the magnetic intensity for South America was investigated from nine new data, three from ruins of the Guaraní Jesuit Missions and six from archaeological sites associated with jerky beef farms, both located in Rio Grande do Sul, Brazil, with ages covering the last 400 years. These data combined with the regional archaeointensity database, demonstrates that the influence of significant non-dipole components in South America started at ~1800 CE. Finally, from a reassessment of the global archaeointensity database, a new interpretation was proposed about the geomagnetic axial dipole evolution, where this component falls constantly since ~700 CE associated to the breaking of the symmetry of the advective sources operating in the outer core. / Variações temporais do campo magnético da Terra fornecem uma grande diversidade de informações geofísicas sobre a dinâmica das diferentes camadas da Terra. Por ser um campo planetário, aspectos regionais e globais podem ser explorados, dependendo da escala de tempo das variações. Nesta tese, foram investigadas as variações do campo geomagnético para os dois últimos milênios. Para isso, aprimoramentos nos métodos de aquisição da intensidade geomagnética registrada em materiais arqueológicos foram realizados, bem como a aquisição de novos dados e uma avaliação crítica da base de dados arqueomagnética global. Dois novos avanços metodológicos são aqui propostos, sendo eles: i) correção para o método de micro-ondas do efeito da taxa de resfriamento, que está associada à diferença entre os tempos de resfriamento durante a manufatura do material e o das etapas de aquecimento durante o experimento de arqueointensidade; (ii) teste para correção da anisotropia termorremanente a partir da média aritmética de seis amostras posicionadas ortogonalmente umas às outras durante o experimento de arqueointensidade. A variação temporal da intensidade magnética para a América do Sul foi investigada a partir de nove dados inéditos, sendo três provenientes das ruínas das Missões Jesuíticas Guaraníticas e seis de sítios arqueológicos associados a fazendas de charque, ambos localizados no Rio Grande do Sul, Brasil, com idades que cobrem os últimos 400 anos. Esses dados, combinados com o banco de dados regionais de arqueointensidade, demonstram que a influência significativa de componentes não-dipolares do campo magnético na América do Sul começou em ~1800 CE. Finalmente, a partir de uma reavaliação do banco de dados globais de arqueointensidade uma nova interpretação foi proposta a respeito da evolução do dipolo axial geomagnético, sugerindo que essa componente está decrescendo constantemente desde ~700 CE devido à quebra da simetria das fontes advectivas que operam no núcleo externo.

Apresenta-se uma avaliação do potencial de alguns solos não lateríticos, compactados, para uso como barreira impermeável, com bases em suas condutividades hidráulicas e contrações axiais. Dez tipos diferentes de solos foram analisados, sendo seis classificados como Não Laterítico Argiloso (NG\') e quatro como Não Laterítico Siltoso (NS\') de acordo com o sistema de classificação MCT. Nas análises foi verificada a influência de parâmetros de compactação e de algumas propriedades dos solos na condutividade hidráulica e na contração axial dos solos compactados. Verificou-se que, para a maioria dos solos houve a diminuição da condutividade hidráulica com o aumento da energia de compactação. Com relação à umidade de moldagem, os menores valores de condutividade hidráulica estiveram associados a umidades iguais ou acima da ótima. Alguns solos não tiveram a condutividade hidráulica influenciados pelo teor de umidade, talvez como reflexo de suas características de compactação, pois mostraram massa específica constante com a umidade, para uma dada energia de compactação. Constatou-se que a condutividade hidráulica diminui com o aumento do índice de plasticidade, da umidade volumétrica e com os resultados do ensaio de absorção de azul de metileno. Para a contração axial nota-se que ela foi pouco influenciado pelo aumento do teor de umidade e pela energia de compactação, estando os maiores valores associados às menores condutividades hidráulicas. Constatou-se que a contração aumenta com o aumento da porcentagem de argila, do índice de plasticidade, dos resultados do ensaio de azul de metileno e com a diminuição do limite de contração. / It is presented an evaluation of the potential of certain non-lateric soils, compacted, for lining system use, based on their hydraulic conductivity and axial shrinkages. Ten different types of soils were analyzed; six of them were classified as non-lateric clayey (NG\') and the other four as non-lateric silty (NS\'), according to the classification system MCT. It was verified the influence of parameters of compaction and some soil properties on the hydraulic conductivity and on the axial shrinkage of compacted soils. Results of the analysis indicate that, for the most of the soils there were decrease of hydraulic conductivity when increasing the energy of compaction. In relation to the molding water content, the lower values of hydraulic conductivity were associated to equal to or over optimum water content. Some soils did not have their hydraulic conductivity influenced by the water content, perhaps as a result of their compaction characteristics, since they showed constant specific mass with the humidity, for a given energy of compaction. It was verified that the hydraulic conductivity decreases as plasticity index and volumetric humidity increases, with the result of the adsorption of metilen blue. The axial shrinkage was very little influenced by the increase of the water content and by the energy of compaction, the greater values associated to lower hydraulic conductivity. It was verified that the contraction increases with the increases of clay content, plasticity index, results of metilen blue test and the decrease of the contraction limit.

Aujourd’hui, la fabrication des turbomachines est conditionnée par des normes de plus en plus restrictives. L'enjeu industriel pour les chercheurs est d'envisager des solutions optimales visant à réduire les sources de perte d'énergie, d'instabilité et du bruit, en particulier l'écoulement de jeu (débit de fuite). Des actions préliminaires ont été élaborées à Arts & Métiers ParisTech sur le rotomoulage du ventilateur axial de refroidissement d'automobile. L'idée de ce travail est d'utiliser la forme creuse induite par le rotomoulage afin de l'exploiter dans le controle de l'écoulement de jeu radial par soufflage rotatif. Pour cela, la virole comporte des trous d'injection orientés de façon à réduire simultanément le débit de fuite et le couple. Dans ce travail, trois parties ont été traité. La première concerne la réalisation du ventilateur par rotomoulage. La deuxième concerne l'étude expérimentale menée dans le banc d'essai ISO 5801. Cette étude comporte la réalisation d'un montage dédié au contrôle par soufflage rotatif, la métrologie menée pour la détermination des performances globales et la caractérisation de la vitesse axiale du sillage proche. La troisième partie traite la modélisation numérique des conditions expérimentales rentables ensuite l'extrapolation du travail vers des taux d'injection importants. Pour ce dernier, on arrive à annuler le débit de fuite avec un gain considérable du couple mettant ainsi le ventilateur en autorotation. / Nowadays, the manufacture of turbomachinery is conditioned by more and more restrictive rules. The industrial challenge for researchers has to consider optimal solutions to reduce sources of energy loss, instability and noise, particularly the tip clearance flow (leakage flow rate). Preliminary actions have been developed at Arts & ParisTech on rotational molding process used for the automobile cooling axial fan. The idea of this work is to use the hollow shape induced by rotational molding process in order to exploit it in the control of tip clearance flow through rotary steady air injection. For this, the shroud ring is composed of injection holes oriented in such away to reduce both of leakage flow rate and the torque. In this work, the thesis focuses on three parts. The first concerns the build of the fan by rotational molding process. The second concerns the experimental study carried out in the ISO 5801 test bench. This study involves the realization of drive system dedicated to rotary steady air injection, metrology for performance determination and the characterization of the near wake axial velocity. The third part deals with the numerical modeling of efficient experimental conditions, then the extrapolation of work towards high injection rates. For this latter, it is possible to cancel leakage flow rate with a considerable gain of the torque thus putting the fan in autorotation.

Les phénomènes d’interaction fluide-structure jouent un rôle important dans le calcul de tenue au séisme des assemblages combustibles. Afin de quantifier les marges de dimensionnement, le modèle de forces fluides utilisé doit être validé et affiné. Pour cela, des campagnes d’essais à l’échelle industrielle ont été réalisées en amont de la thèse. L’objectif ici est de contribuer à l’interprétation des essais industriels pour le cas stationnaire, et de valider les méthodes numériques permettant de simuler ce type d’écoulement. La problématique industrielle s'inscrit dans la tradition de l'étude des structures élancées sous écoulement axial. Le modèle de force fluide locale généralement utilisé, que nous appelons modèle de Taylor-Lighthill-Païdoussis (TLP), consiste en stationnaire à combiner un terme de force fluide potentielle, proportionnel à la courbure, et un terme de force fluide visqueuse, proportionnel à la pente. Des versions dynamiques de ce modèle ont été employées avec succès pour prédire le comportement vibratoire de cylindres flexibles en écoulement axial. Néanmoins, la littérature propose très peu de données de validation directe de cette représentation des forces fluides. Afin d’acquérir de telles données, pour le cas particulier d’un cylindre confiné dans un réseau de cylindres, un nouveau banc d’essai a été conçu et mis en place au laboratoire. Il s’agit d’un faisceau de 3x3 cylindres disposé dans une veine de soufflerie. Le cylindre central possède trois degrés de liberté : rotation, translation, flexion. Les efforts fluides résultants sont mesurés à l’aide d’une balance. Un modèle numérique similaire à la maquette est aussi réalisé et donne accès aux forces fluides locales. Les forces globales obtenues numériquement et expérimentalement sont comparables. Les forces locales obtenues dans les simulations numériques s’expliquent bien à l’aide du modèle TLP, en ignorant les effets de bord à l’entrée et à la sortie du faisceau. La transposition au cas industriel, de géométrie plus complexe, est réalisable par recalage des coefficients du modèle. / Fluid-structure interaction phenomena play a major role in the seismic design of fuel assemblies. In order to evaluate the design margins, the implemented model of fluid forces needs to be carefully assessed. Industrial-scale tests have been carried out with that purpose. Our goal is to contribute to their interpretation in the steady case, and to validate CFD methods usually applied to the type of flow at stake here. This fits in the tradition of the study of slender structures in axial flow. The local steady fluid forces decompose in a potential term, which is proportional to the curvature of the structure, and a viscous term, proportional to the angle of incidence. Adapted versions of this representation, which we call Taylor-Lighthill-Païdoussis (TLP) model, have proved successful in predicting the dynamic behaviour of flexible cylinders in axial flow. However, there is a lack in the literature of sound validation data for the fluid forces themselves. In order to gather such data, a new test rig has been designed and built. It consists in a 3x3 cylinder bundle confined in a wind tunnel. The central cylinder can be rotated, translated or bent. Resultant fluid forces are measured using a load cell. CFD calculations give access to the local fluid forces. CFD and experiments give similar results on the global fluid forces. The TLP model performs well at predicting the local fluid forces, except in the inlet and outlet regions. It can be fitted to the industrial case by adapting its coefficients.

Dentro do conjunto de aspectos relacionados à elaboração de projetos em estruturas de aço e mistas de aço e concreto, destaca-se como de grande importância e interesse, para fins de dimensionamento, a consideração de elementos estruturais submetidos a temperaturas elevadas. Nesse sentido, o presente trabalho tem como objetivo principal propor a construção de modelos numéricos tridimensionais de pilares de aço pertencentes a sistemas estruturais correntes da construção civil, para análise em situação de incêndio, com vistas a simular numericamente a evolução dos níveis de temperatura ao longo do tempo com posterior acoplamento termoestrutural. Considera-se uma análise paramétrica com vista a variar as restrições axiais totais e parciais da barra, no referente aos deslocamentos axiais, contemplando desde a situação de extremidade livre até a restrição completa em resposta à consideração de apoio do tipo fixo, por exemplo. Os resultados numéricos são comparados a ensaios experimentais de outros autores, bem como com outros trabalhos numéricos já publicados. São obtidas respostas de deslocamentos axiais e laterais do modelo termoestrutural para diversas disposições de paredes em relação ao perfil, bem como gráficos do acréscimo de força axial introduzido no sistema pela restrição axial. Os estudos aqui realizados poderão servir como base para novas pesquisas tanto no campo numérico quanto experimental, assim como para futuras revisões da ABNT NBR 14323:1999, buscando contemplar situações de interesse não abordadas neste documento normativo. Os resultados da pesquisa apontam que a consideração do campo térmico com a inclusão da alvenaria no modelo termoestrutural pode melhorar consideravelmente o desempenho do elemento estrutural em situação de incêndio. / Within the set of aspects related to the development of researches in steel and composite steel and concrete structures, stands out with great importance and interest, aiming to dimension, the consideration of structural elements subjected to high temperatures. In this way, the present work has as main objective to propose the construction of three-dimensional numerical models of steel columns that belong to current structural systems of civil construction, for examination in fire situation, aiming to simulate numerically the evolution of temperature levels throughout of time with later termoestrutural coupling. It will be considered a parametric analysis in order to vary the total and partial axial restraint in respect to the axial displacements, since the free end situation until the complete restriction in response to the consideration of support for the fixed type, for example. The numerical results are compared to experimental tests made by other authors, as well as with others numerical works already published. Answers are obtained from axial and lateral displacements of the thermo structural model to many displacement of wall related to the profile, also charts of adding axial force introduced into the system by the axial restraint. The results of the current research could serve as a basis for further research in both the numerical field or experimental, also for future revisions of ABNT NBR 14323:1999, aiming to see situations of interest not studied in the same normative document. The results of this work show that consideration of thermal field with the inclusion of masonry in the thermo structural model can, significantly, improve the performance of the structural element in a fire situation.

Developments in high-performance computing instruments and advancements in the numerical algorithms combined with lattice gauge theory make it possible to simulate Quantum Chromodynamics (QCD), the theory of strongly-interacting quarks and gluons, numerically at nearly physical light-quark masses. In this work we present our results for the $D^*Dpi$ coupling constant as simulated on $32^3 imes 64$, unquenched $2+1$-flavor lattices. We estimate the coupling at the chiral limit as $g_{D^*Dpi} = 16.23 pm 1.71$, which is in good agreement with its experimental value $g^{(exp)}_{D^*Dpi} = 17.9pm0.3pm1.9$ as obtained by CLEO II Collaboration.

Preclinical PET systems image animal models of chronic human disease that are used to evaluate new therapeutic strategies for the treatment of cancer and other diseases. Once these animals are out of a controlled environment for PET imaging, they typically can not be taken back as they may have been exposed to outside disease. A highly compact PET system is thus required to be developed that can operate within a bio-safety cabinet inside a barrier facility. We investigated using 100-mm-long LYSO scintillator crystals oriented in the axial direction and read out at both ends by position sensitive photomultiplier tubes (PSPMTs) to construct a compact PET. The optimization of light collection for axial encoding of events was carried out using different reflector materials and surface treatments of 3 × 2 × 100 mm3 and 2 × 2 × 100 mm3 polished crystals. The detector response was examined by irradiating the crystals at discrete positions using an electronically collimated 511 keV photon beam. The ratio of two PSPMT signals was used to find the axial-resolution while their sum was used to determine the energy resolution. We then explored the effects of creating systematic band patterns of surface roughing on 1 to 4 long surfaces of the crystals to modulate light-transport with the goal of further improving axial-resolution. These experimental results were used to benchmark DETECT2000 Monte Carlo simulations for our detector geometry. The axial-positioning calibration was carried out by evaluating a uniform flood-irradiation method and comparing with the collimated-irradiation method using 2 × 2 × 100 mm3 crystal detectors. The best axial-positioning resolution of 3.4 mm was achieved in this study for 2 × 2 × 100 mm3 Teflon-wrapped crystals with banding-patterns on only two opposite surfaces, fulfilling the design criteria of our proposed PET. The benchmarked DETECT2000 models can now be used to predict the performance of a complete detector module design. The calibration methods agreed if the trigger threshold energies were adjusted to give similar single event rates in both PSPMTs for uniform flood-irradiation. The implementation of flood-irradiation method in our complete PET scanner will provide a simple axial-positioning calibration.

Preclinical PET systems image animal models of chronic human disease that are used to evaluate new therapeutic strategies for the treatment of cancer and other diseases. Once these animals are out of a controlled environment for PET imaging, they typically can not be taken back as they may have been exposed to outside disease. A highly compact PET system is thus required to be developed that can operate within a bio-safety cabinet inside a barrier facility. We investigated using 100-mm-long LYSO scintillator crystals oriented in the axial direction and read out at both ends by position sensitive photomultiplier tubes (PSPMTs) to construct a compact PET. The optimization of light collection for axial encoding of events was carried out using different reflector materials and surface treatments of 3 × 2 × 100 mm3 and 2 × 2 × 100 mm3 polished crystals. The detector response was examined by irradiating the crystals at discrete positions using an electronically collimated 511 keV photon beam. The ratio of two PSPMT signals was used to find the axial-resolution while their sum was used to determine the energy resolution. We then explored the effects of creating systematic band patterns of surface roughing on 1 to 4 long surfaces of the crystals to modulate light-transport with the goal of further improving axial-resolution. These experimental results were used to benchmark DETECT2000 Monte Carlo simulations for our detector geometry. The axial-positioning calibration was carried out by evaluating a uniform flood-irradiation method and comparing with the collimated-irradiation method using 2 × 2 × 100 mm3 crystal detectors. The best axial-positioning resolution of 3.4 mm was achieved in this study for 2 × 2 × 100 mm3 Teflon-wrapped crystals with banding-patterns on only two opposite surfaces, fulfilling the design criteria of our proposed PET. The benchmarked DETECT2000 models can now be used to predict the performance of a complete detector module design. The calibration methods agreed if the trigger threshold energies were adjusted to give similar single event rates in both PSPMTs for uniform flood-irradiation. The implementation of flood-irradiation method in our complete PET scanner will provide a simple axial-positioning calibration.

Dans le cadre du développement du véhicule électrique hybride, les machines électriques pour la traction sont l’objet d’un effort toujours plus important de recherche et de développement. En particulier, les contraintes d’encombrement allouées à ces machines sont toujours plus sévères et la recherche se porte vers des structures de machines compactes. C’est dans ce contexte que nos travaux se sont portés sur l’étude et le dimensionnement de machine à flux axial pour une application hybridation douce (Mild Hybrid) d’alterno-démarreur monté sur vilebrequin de puissance 50 kW et de couple 205 Nm en régime transitoire. Un état de l’art des machines à flux axial est présenté. Une analyse des configurations de bobinage avec la méthode de l’étoile des encoches est détaillée. Un début d’analyse de la machine à commutation de flux est proposé. La méthodologie de dimensionnement est étayée. Elle repose sur des études de sensibilité, un dimensionnement paramétrique, mais aussi une optimisation de la machine. Les modèles utilisés sont de type éléments finis et surface de réponse par plan d’expériences. Enfin, une étude thermique de la machine est effectuée et des pistes sont données pour l’amélioration de l’échange thermique par refroidissement diphasique. / In the context of development of the hybrid electric vehicle, electric machines for traction are under extensive investigation. In particular, volume constraints are more and more severe and research is carried out towards compact structures. This work is focused on the study and the design of axial flux machine for a mild-hybrid application of an integrated starter generator mounted on the crankshaft. Its ratings in transient mode are 50 kW and 205 Nm. A literature review of axial flux machines is presented. A analysis of winding configurations with star of slots method is detailed. A beginning of analysis of switching-flux machine is proposed. The methodology of design is detailed. It is based on sensitivity analysis, parametric design and optimization of the machine. Utilized models are finite element model and response surface by design of experiments. Finally, a thermal study of the machine is carried out and some ideas are given to improve the thermal exchange by diphase cooling.