CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Great works of infrastructure such as hydroelectric plants require, in it building, large concrete volumes classified as mass concrete structures. These works of power generation are strategic and fundamental for the development of a nation. However, during construction and throughout its life they may have pathological manifestations that compromise its stability. One of the most common problems in this type of structure is cracking caused by heat generated due to the exothermic reaction of cement hydration. Therefore, we had to analyze the thermal behavior of concrete, concrete with similar consistency and resistance like the concrete utilized in construction dam, and analyze how the type of cement utilized and its contents affects these parameters. In addition, we studied the evolution of compressive strength and dynamic modulus of elasticity as the cement hydrates. Finally, we compared the thermal performance of concretes produced with the results obtained from a commercial software. To carry out the experiment, concrete blocks were produced of 1,5m with cements CP II E 32 RS and CP IV 32 with consumption 241,2 kg/m and 330,0 kg/m for thermal analysis, besides cylindrical specimens for the remaining analyzes. The results showed that the thermal behavior of concrete has a small dependence on the type of cement, however the cement content affects too much this behavior, and the cement CP IV 32 showed higher thermal variations. It was also observed that the development of compressive strength is strongly dependent on the cement content, but it has low dependency on the type of cement. Computer modeling presented satisfactory results when it was compared to results of the thermal evolution blocks. / As grandes obras de infraestrutura como as centrais hidroelÃtricas requerem na sua construÃÃo grandes volumes de concreto, sendo classificadas como estruturas de concreto massa. Essas obras de geraÃÃo de energia sÃo estratÃgicas e fundamentais para o desenvolvimento de uma naÃÃo. Entretanto, durante sua construÃÃo e ao longo de sua vida Ãtil estas podem apresentar manifestaÃÃes patolÃgicas que comprometem sua estabilidade. Um dos problemas mais comuns nesse tipo de estrutura à a fissuraÃÃo causada pela energia tÃrmica gerada devido à reaÃÃo exotÃrmica de hidrataÃÃo do cimento. Diante disso, buscou-se analisar como se dà o comportamento tÃrmico de concretos utilizados para a construÃÃo de corpo de barragem, alÃm de analisar como o tipo de cimento utilizado e o seu teor afetam a variaÃÃo de temperatura da massa de concreto e os problemas causados por essa variaÃÃo. Buscou-se ainda analisar a evoluÃÃo da resistÃncia à compressÃo e do mÃdulo de elasticidade dinÃmico à medida que o cimento se hidratava. Por fim, comparou-se o comportamento tÃrmico dos concretos produzidos com os resultados obtidos por meio de um software comercial. Para a realizaÃÃo da parte experimental produziu-se blocos de concretos de 1,5 metros cÃbicos com cimentos CP II-E 32 RS e CP IV 32 com consumo de 241,2 kg/m e 330,0 kg/m para anÃlise tÃrmica, alÃm da moldagem de corpos de prova cilÃndricos para as demais anÃlises. Os resultados apontaram que o comportamento tÃrmico do concreto apresenta uma pequena dependÃncia do tipo de cimento. Entretanto, o teor de cimento afeta fortemente esse comportamento, sendo o cimento CP IV 32 o que apresentou maiores variaÃÃes tÃrmicas. Observou-se tambÃm que a evoluÃÃo da resistÃncia à compressÃo à fortemente dependente da quantidade de cimento, mas apresenta baixa dependÃncia do tipo de cimento. A modelagem computacional apresentou resultados satisfatÃrios quando comparado aos resultados da evoluÃÃo tÃrmica dos blocos produzidos.

As características das matérias-primas particuladas como tamanho, forma, área específica, entre outras, determinam não somente o desempenho final de um produto, mas também o processo de sua fabricação. Neste sentido, matérias-primas sintéticas são produzidas por meio de conversões químicas que têm como finalidade o controle da reprodutibilidade de características. Esta tese tem como objetivo o estudo de precursores sintetizados com matérias-primas nacionais de elevada pureza, quanto à área específica (AE), estrutura cristalina e morfologia das fases formadas durante as transformações térmicas de alguns hidróxidos (gibsita e pseudoboemita), sais (acetato e formato) e sulfatos duplos (de amônio e de sódio) de alumínio. As amostras sintetizadas e aquecidas foram caracterizadas por DRX, MEV, BET e análise térmica (TG, DTA e DSC), a fim de que fossem observadas as variações nas características das fases formadas. Observou-se que todos os precursores, à exceção do \"sulfato-Na\", evoluem termicamente resultando como produto final somente a a-alumina. No caso particular do \"sulfato-Na\", em que se apresenta resultados preliminares, verifica-se a formação, além da a- alumina, de B-alumina. Os hidróxidos e os sais de alumínio passam por uma seqüência de aluminas de transição que exibem valores de área específica elevados. Com relação à pseudoboemita, além da caracterização proposta no trabalho, foi estudada a influência do método de secagem e do tempo de envelhecimento da pseudoboemita nas características dos materiais sintetizados. Verificou-se que o método de secagem pode influenciar as temperaturas de transformações de fases das aluminas. Precursores secos por nebulização podem formar a fase a concomitantemente com a fase 0, o que não ocorre com os materiais secos ao ar. Já o tempo de envelhecimento influenciou no tamanho final das fibrilas de pseudoboemita. Tanto o método de secagem quanto o tempo de maturação afetam de forma determinante a organização das fibrilas que, por sua vez, estabelecem a distribuição de poros nos materiais produzidos. / Features of powdered raw materials like size, morphology, specific area, determine the product performance, besides the fabrication process product. In this direction, the synthetic raw materials are produced by means of chemical conversion to control the characteristics reprodutibility. This thesis has as objective the study of precursor\'s synthesized with national raw materials of raised pureness, by the study if the specific area (AE), crystalline structure and morphology of the phases formed during thermal transformation of some hydroxides as (aluminum hydroxides- gibbsite and pseudoboehmite; aluminum salts - acetate and formate and aluminum sulphates - sodium and amonium) produzed by high pure nacional raw materials. The sythetized and heated samples are examined by DRX, MEV, BET and thermal analysis (TG, DTA e DSC) to verify the characteristics variations in the formed phases. It\'s can be seen that every thermal treated precursors evolve to a-alumina. In the particular case of \"Na-sulfate\", the preliminary results present also B-alumina. The hydroxides and salts pass by a sequence of alumina transition, that show high specific area. In the case of pseudoboehmite, was also studied the influence of dried method and the aging of aqueous aluminum hydroxide gels in the characteristic of synthesized materials. It verified that the dried method can influence the temperature of the alumina phase\'s transitions. Dried precursors by spray drier can form the phase a and 0 together, this not occur with the others. The aging can influence in the pseudoboehmite microfibrils size. The dried method and the aging influence the organization microfibrils, and this one determines the pore distribution from the produced materials.

Indiana University-Purdue University Indianapolis (IUPUI) / Fused deposition modeling (FDM) represents one of the most common techniques for rapid proto-typing in additive manufacturing (AM). This work applies image based thermography to monitor the FDM process in-situ. The nozzle temperature, print speed and print orientation were adjusted during the fabrication process of each specimen. Experimental and numerical analysis were performed on the fabricated specimens. The combination of the layer wise temperature profile plot and temporal plot provide insights for specimens fabricated in x, y and z-axis orientation. For the x-axis orientation build possessing 35 layers, Specimens B16 and B7 printed with nozzle temperature of 225 C and 235 C respectively, and at printing speed of 60 mm/s and 100 mm/s respectively with the former possessing the highest modulus, yield strength, and ultimate tensile strength. For the y-axis orientation build possessing 59 layers, Specimens B23, B14 and B8 printed with nozzle temperature of 215 C, 225 C and 235 C respectively, and at printing speed of 80 mm/s, 80 mm/s and 60 mm/s respectively with the former possessing the highest modulus and yield strength, while the latter the highest ultimate tensile strength. For the z-axis orientation build possessing 1256 layers, Specimens B6, B24 and B9 printed with nozzle temperature of 235 C, 235 C and 235 ➦C respectively, and at printing speed of 80 mm/s, 80 mm/s and 60 mm/s respectively with the former possessing the highest modulus and ultimate tensile strength, while B24 had the highest yield strength and B9 the lowest modulus, yield strength and ultimate tensile strength. The results show that the prints oriented in the y-axis orientation perform relatively better than prints in the x-axis and z-axis orientation.

A Formação Serra Alta é constituída por uma sequência de folhelhos e siltitos cinza supostamente de origem marinha. Esta unidade é uma potencial rocha geradora de hidrocarbonetos e zona preferencial para alojamento de sills associados ao magmatismo Serra Geral. Visando a caracterização do potencial gerador de hidrocarbonetos, a evolução térmica e os paleofluidos diagenéticos da Formação Serra Alta, foram realizadas medidas de concentração de carbono orgânico total (COT) e hidrogênio (H) em amostras coletadas em afloramentos e estudos isotópicos e de inclusões fluidas em materiais diagenéticos. Os teores de carbono orgânico total (COT) e hidrogênio (H) para as amostras de folhelhos da Formação Serra Alta estão situados entre 0,1 e 0,5% e entre 0,24 e 3,20%, respectivamente. Os dados microtermométricos apresentaram temperaturas de homogeneização (Th) que variaram de 55 a 220°C, temperaturas eutéticas (Te) de -57,5 a -49,5ºC (sistema H2O + NaCl + CaCl2) e temperaturas de fusão do gelo (Tfg) de -2,5 a 1,0°C, indicativas de salinidades baixas, entre 0 e 4,2% em peso de NaCl equivalente. Os resultados de \'\'delta\'\' POT.13\'\'C IND.PDB\' e \"delta\'\'POT.18\' \'O IND.PDB\' das amostras de veio e cimento de calcita demonstram valores negativos (%o), tanto para \'delta\'\'POT.13\' C quanto para \'delta\'\'POT.18 O. Enquanto os valores de \'delta\'\'POT.13\'\' C IND.PDB\' do cimento dos folhelhos da Formação Serra Alta variam entre -8,6 e -2,3%o, os veios de calcita apresentam uma estreita faixa de valores entre -5,1 e -3,7%o. Os teores de COT indicam potencial de geração de óleo e gás considerado baixo para os folhelhos da Formação Serra Alta. As características das inclusões (monofásicas associadas a bifásicas com pequena variação nas proporções volumétricas entre as fases), as salinidades relativamente constantes associadas às grandes variações em Th são indicativos de aprisionamento em zona freática de baixa temperatura (<50°C) com posterior reequilíbrio térmico causado por stretching devido ao soterramento e à presença de corpos ígneos. Os pleofluidos aquosos aprisionados como inclusões em zona de baixa temperatura, antes do pico térmico do Cretáceo, explicariam a ausência de inclusões fluidas primárias de hidrocarbonetos nos veios de calcita. As Th acima de 150ºC indicam elevada maturidade térmica alcançada pela Formação Serra Alta em função do soterramento e do magmatismo Serra Geral. Estes resultados são semelhantes aos obtidos para as formações adjacentes (Irati e Teresina) à Formação Serra Alta. Valores de \'delta\'\'POT.13\'\'C IND.PDB\' e \'delta\'\'POT.18\'\'O IND.PDB\' para o cimento carbonático dos folhelhos, revelam duas gerações ou duas fases de precipitação distintas da calcita. A primeira geração compatível com assinatura isotópica próxima ao fluido marinho original (\'delta\'\'POT.13\' C entre -2,3 e -4,6%o e \'delta\'\'POT.18\'O entre -7,6 e 1,4%o) e a segunda geração compatível com assinatura isotópica de um fluido diagenético de origem meteórica (\'delta\'\'POT.13\' C entre -6,2 e -8,6%o e \'delta\'\'POT.18\'O entre -8,4 e -4,1%o). Assim, a hipótese de origem meteórica para os fluidos percolantes nas fraturas corrobora a salinidade baixa registrada nas inclusões fluidas dos veios de calcita, mas com alguma influência ou modificação por meio de fluidos pré-existentes, que interagiram com carbonatos marinhos das unidades estratigráficas adjacentes (formações Irati e Teresina) à Formação Serra Alta. / The Serra Alta Formation at the eastern border of the Paraná Basin consists of a sequence of gray shales and siltstones presumably of marine origin. This unit is a potential source rock for hydrocarbons and preferred area for hosting sills associated with the early Cretaceous Serra Geral magmatism. In order to characterize the hydrocarbon generation potential, the thermal evolution and diagenetic paleofluids of the Serra Alta Formation, were performed measurements of concentration of total organic carbon (TOC) and hydrogen (H), in shale samples collected from outcrops, and isotope and fluid inclusions studies on diagenetic calcite. The total organic carbon (TOC) and hydrogen (H) contents for shale samples of the Serra Alta Formation lie between 0.1 and 0.5% and between 0.24 and 3.20% respectively. The microthermometry data show homogenization temperature (Th) ranging from 55 to 220°C, eutectic temperature (Te) from -57.5 to -49.5°C (H2O + CaCl2 + NaCl system) and ice melting temperatures from -2.5 to 1.0°C, indicative of low salinity between 0 and 4.2 wt. % of NaCl equivalent. \'delta\'\'POT.13\'\'IND.CPDB\' and \'delta\'\'POT.18\'O IND.PDB\' results from samples of calcite cement and veins demonstrate negative values (%o), both for \'delta\'\'POT.13\'C and for \'delta\'\'POT.18\'O. While the values \'delta\'\'POT.13\'C IND.PDB\' cement of the Serra Alta Formation shales vary between -8.6 and -2.3%o, the calcite veins have a narrow range of values between -5.1 and -3.7%o. The TOC content indicate that the shales of the Serra Alta Formation have low potential for oil and gas generation. The association of one-phase and two-phase fluid inclusions with small variations in volumetric ratio between phases and the relatively constant salinity associated with large variations in Th are indicative of fluid trapping in low temperature (<50°C) groundwater zone, with subsequent thermal reequilibrium caused by stretching due to burial and the presence of igneous bodies. The fluid trapping at this low temperature zone, before Cretaceous thermal peak, would explain the absence of hydrocarbon primary fluid inclusions in the calcite veins. Temperatures of homogenization higher than 150ºC indicate high thermal maturity achieved by the Serra Alta Formation due to burial and the Serra Geral magmatism. These results are similar to those obtained for the adjacent formations (Irati and Teresina) of the Serra Alta. \'delta\'\'POT.13\'C IND.PDB\' and \'delta\'\'POT.18\'O IND.PDB\' values for carbonate cement reveal two generations or two distinct phases of calcite precipitation. The first generation is compatible with isotopic signature close to the original marine carbonate (\'delta\'\'POT.13\'C between -2.3 and -4.6%o and \'delta\'\'POT.18\'O between -7.6 and 1.4%o) and the second generation is compatible with isotopic signature of a diagenetic fluid of meteoric origin (\'delta\'\'POT.13C between -6.2 and -8.6%o and \'delta\'\'POT.18\'O between -8.4 and -4.1%o). Thus, the meteoric origin for the paleofluids percolating in fractures corroborates the low salinity recorded in fluid inclusions from veins of calcite, but with some influence of paleofluids, which interacted with marine carbonates of stratigraphic units (Irati and Teresina formations) adjacent to the Serra Alta Formation.

A Formação Serra Alta é constituída por uma sequência de folhelhos e siltitos cinza supostamente de origem marinha. Esta unidade é uma potencial rocha geradora de hidrocarbonetos e zona preferencial para alojamento de sills associados ao magmatismo Serra Geral. Visando a caracterização do potencial gerador de hidrocarbonetos, a evolução térmica e os paleofluidos diagenéticos da Formação Serra Alta, foram realizadas medidas de concentração de carbono orgânico total (COT) e hidrogênio (H) em amostras coletadas em afloramentos e estudos isotópicos e de inclusões fluidas em materiais diagenéticos. Os teores de carbono orgânico total (COT) e hidrogênio (H) para as amostras de folhelhos da Formação Serra Alta estão situados entre 0,1 e 0,5% e entre 0,24 e 3,20%, respectivamente. Os dados microtermométricos apresentaram temperaturas de homogeneização (Th) que variaram de 55 a 220°C, temperaturas eutéticas (Te) de -57,5 a -49,5ºC (sistema H2O + NaCl + CaCl2) e temperaturas de fusão do gelo (Tfg) de -2,5 a 1,0°C, indicativas de salinidades baixas, entre 0 e 4,2% em peso de NaCl equivalente. Os resultados de \'\'delta\'\' POT.13\'\'C IND.PDB\' e \"delta\'\'POT.18\' \'O IND.PDB\' das amostras de veio e cimento de calcita demonstram valores negativos (%o), tanto para \'delta\'\'POT.13\' C quanto para \'delta\'\'POT.18 O. Enquanto os valores de \'delta\'\'POT.13\'\' C IND.PDB\' do cimento dos folhelhos da Formação Serra Alta variam entre -8,6 e -2,3%o, os veios de calcita apresentam uma estreita faixa de valores entre -5,1 e -3,7%o. Os teores de COT indicam potencial de geração de óleo e gás considerado baixo para os folhelhos da Formação Serra Alta. As características das inclusões (monofásicas associadas a bifásicas com pequena variação nas proporções volumétricas entre as fases), as salinidades relativamente constantes associadas às grandes variações em Th são indicativos de aprisionamento em zona freática de baixa temperatura (<50°C) com posterior reequilíbrio térmico causado por stretching devido ao soterramento e à presença de corpos ígneos. Os pleofluidos aquosos aprisionados como inclusões em zona de baixa temperatura, antes do pico térmico do Cretáceo, explicariam a ausência de inclusões fluidas primárias de hidrocarbonetos nos veios de calcita. As Th acima de 150ºC indicam elevada maturidade térmica alcançada pela Formação Serra Alta em função do soterramento e do magmatismo Serra Geral. Estes resultados são semelhantes aos obtidos para as formações adjacentes (Irati e Teresina) à Formação Serra Alta. Valores de \'delta\'\'POT.13\'\'C IND.PDB\' e \'delta\'\'POT.18\'\'O IND.PDB\' para o cimento carbonático dos folhelhos, revelam duas gerações ou duas fases de precipitação distintas da calcita. A primeira geração compatível com assinatura isotópica próxima ao fluido marinho original (\'delta\'\'POT.13\' C entre -2,3 e -4,6%o e \'delta\'\'POT.18\'O entre -7,6 e 1,4%o) e a segunda geração compatível com assinatura isotópica de um fluido diagenético de origem meteórica (\'delta\'\'POT.13\' C entre -6,2 e -8,6%o e \'delta\'\'POT.18\'O entre -8,4 e -4,1%o). Assim, a hipótese de origem meteórica para os fluidos percolantes nas fraturas corrobora a salinidade baixa registrada nas inclusões fluidas dos veios de calcita, mas com alguma influência ou modificação por meio de fluidos pré-existentes, que interagiram com carbonatos marinhos das unidades estratigráficas adjacentes (formações Irati e Teresina) à Formação Serra Alta. / The Serra Alta Formation at the eastern border of the Paraná Basin consists of a sequence of gray shales and siltstones presumably of marine origin. This unit is a potential source rock for hydrocarbons and preferred area for hosting sills associated with the early Cretaceous Serra Geral magmatism. In order to characterize the hydrocarbon generation potential, the thermal evolution and diagenetic paleofluids of the Serra Alta Formation, were performed measurements of concentration of total organic carbon (TOC) and hydrogen (H), in shale samples collected from outcrops, and isotope and fluid inclusions studies on diagenetic calcite. The total organic carbon (TOC) and hydrogen (H) contents for shale samples of the Serra Alta Formation lie between 0.1 and 0.5% and between 0.24 and 3.20% respectively. The microthermometry data show homogenization temperature (Th) ranging from 55 to 220°C, eutectic temperature (Te) from -57.5 to -49.5°C (H2O + CaCl2 + NaCl system) and ice melting temperatures from -2.5 to 1.0°C, indicative of low salinity between 0 and 4.2 wt. % of NaCl equivalent. \'delta\'\'POT.13\'\'IND.CPDB\' and \'delta\'\'POT.18\'O IND.PDB\' results from samples of calcite cement and veins demonstrate negative values (%o), both for \'delta\'\'POT.13\'C and for \'delta\'\'POT.18\'O. While the values \'delta\'\'POT.13\'C IND.PDB\' cement of the Serra Alta Formation shales vary between -8.6 and -2.3%o, the calcite veins have a narrow range of values between -5.1 and -3.7%o. The TOC content indicate that the shales of the Serra Alta Formation have low potential for oil and gas generation. The association of one-phase and two-phase fluid inclusions with small variations in volumetric ratio between phases and the relatively constant salinity associated with large variations in Th are indicative of fluid trapping in low temperature (<50°C) groundwater zone, with subsequent thermal reequilibrium caused by stretching due to burial and the presence of igneous bodies. The fluid trapping at this low temperature zone, before Cretaceous thermal peak, would explain the absence of hydrocarbon primary fluid inclusions in the calcite veins. Temperatures of homogenization higher than 150ºC indicate high thermal maturity achieved by the Serra Alta Formation due to burial and the Serra Geral magmatism. These results are similar to those obtained for the adjacent formations (Irati and Teresina) of the Serra Alta. \'delta\'\'POT.13\'C IND.PDB\' and \'delta\'\'POT.18\'O IND.PDB\' values for carbonate cement reveal two generations or two distinct phases of calcite precipitation. The first generation is compatible with isotopic signature close to the original marine carbonate (\'delta\'\'POT.13\'C between -2.3 and -4.6%o and \'delta\'\'POT.18\'O between -7.6 and 1.4%o) and the second generation is compatible with isotopic signature of a diagenetic fluid of meteoric origin (\'delta\'\'POT.13C between -6.2 and -8.6%o and \'delta\'\'POT.18\'O between -8.4 and -4.1%o). Thus, the meteoric origin for the paleofluids percolating in fractures corroborates the low salinity recorded in fluid inclusions from veins of calcite, but with some influence of paleofluids, which interacted with marine carbonates of stratigraphic units (Irati and Teresina formations) adjacent to the Serra Alta Formation.

Les planètes rocheuses achèvent leur formation dans des processus collisionnels très énergétiques.L'énergie libérée lors des impacts majeurs a vraisemblablement fondu la surface des planètes, formant ainsi un océan de roches en fusion. Le refroidissement et la solidification de cet « océan de magma » conditionnent la différentiation chimique du manteau et la distribution des éléments volatils entre les différents réservoirs de la planète. C'est lors de cette phase évolutive, commune aux planètes rocheuses, que l'atmosphère est formée par dégazage des volatils et que les conditions initiales de l'évolution future des planètes se mettent en place. C'est ainsi une phase évolutive de première importance pour comprendre l'apparition des océans d'eau primitifs, le démarrage de la convection thermique du manteau et l'actuelle diversité des planètes telluriques.Un modèle numérique couplant l'évolution thermique de l'océan de magma en interaction avec l'atmosphère a été utilisé pour étudier le refroidissement de la planète et les conditions de surface résultantes. Nous avons investigué l'influence du contenu initial en volatil combiné avec la distance orbitale de la planète sur la formation des premiers océans d'eau à la fin du refroidissement, pour des atmosphères avec et sans nuages. Cette approche a ensuite été étendue aux planètes rocheuses extra-solaires orbitant des étoiles froides.Le contenu relatif en H2O et CO2 de l'atmosphère peut empêcher la formation d'océans, menant à des planètes ayant une surface solide sans océans d'eau. Des lois d'échelle prédisent la formation d'océans en fonction du contenu initial en volatil. Une épaisse couche nuageuse diminue la température de surface et maintient des conditions clémentes plus proche de l'étoile rendant ainsi possible la formation d'océan sur Vénus. Ces conditions de surface tempérées pourraient alors être favorable à l'émergence de la vie et suggèrent qu'en fonction de la couverture nuageuse, la Terre et Vénus pourraient être dans un état relativement similaire à la fin de la phase océan de magma, contrairement à ce qui est généralement admis.Pour les étoiles froides, la formation d'océans d'eau n'est possible qu'à des flux stellaires plus faibles que dans notre système solaire, correspondant à des distances étoile-planète relativement plus importantes.L'effet refroidissant des nuages est atténué pour les étoiles froides autour desquelles la bordure intérieure de la zone d'habitabilité tend à être indépendante de la couverture nuageuse. / At the end of the accretion phase, rocky planets grow through high energetic impact processes. Combined with other heat sources, they most likely melt the surface of the planets, forming an ocean of molten rocks. The cooling and solidification of this early so-called magma ocean strongly influences the earliest compositional differentiation and volatile distribution of the planet. Indeed, this common early evolution stage of rocky planets witnesses the degassing of the atmosphere and sets the initial conditions for the long-term evolution of the planets. It is thus of major importance in understanding the formation of the primitive water ocean, the onset of thermally driven mantle convection and the diversity of observed terrestrial planets.Using a coupled magma ocean-atmosphere thermal evolution model, we investigated the cooling of the planet and the surface conditions reached at the end of this early stage. We studied how the initial volatile content and the distance from the star influence the formation of a water ocean at the end of the cooling for both cloud-free and cloudy atmospheres. We extended this approach to planets orbiting colder stars than the Sun.The relative amount of H2O and CO2 in the atmosphere can preclude water ocean formation, leading to solid surface planets without water ocean. Scaling laws are derived to predict the formation of a water ocean as a function of the initial volatile content.The presence of a thick cloud cover extends clement surface conditions close to the star and allows for water ocean formation on early Venus. Such temperate conditions might be suitable for the emergence of life and suggest that, depending on the cloud cover, the Earth and Venus might not be as different as previously thought at the end of the magma ocean stage.For stars colder than the Sun, water ocean formation is shifted to farther star distances. The cooling effect of clouds becomes less efficient for cold stars whose inner edge of the temperate zone tends to be independent of the cloud cover.

In this thesis, we present results of a numerical modelling study focused on the thermal evolution of the Earth and terrestrial planets. We focus particularly on two problems: I) constraining the internal structure of Venus and Mercury using their geoid and surface topography data and II) evaluating the effects of a rhe- ologically distinct post-perovskite on the secular cooling of the Earth. In part I, we performed simulations in a broad group of models of the Venusian man- tle, characterised by different rheological descriptions, and we compared spectra of their geoid and their surface topography with the observed quantities. Our analysis suggested that the geoid and the surface topography of Venus are con- sistent with a radially symmetric viscosity model with a strong 200 km thick lithosphere, without an asthenosphere and with a gradual viscosity increase in the underlying mantle. In the case of Mercury, none of our models was able to predict observed data, thus suggesting other than a dynamic origin of observed geoid and topography. In part II, we investigated style of Earth's mantle con- vection and its long-term evolution in the models that take into account a weak post-perovskite. We conclude that the presence of the weak post-perovskite en- hances the core cooling. This effect is comparable in...

Le procédé de soudage TIG est actuellement le plus utilisé dans l’industrie aéronautique du fait de la qualité des joints de soudure qu’il permet d’obtenir et de sa simplicité d’automatisation. Une opération de soudage provoque des gradients thermiques dus au passage de la source de chaleur sur la pièce qui induisent des déformations et des contraintes résiduelles pouvant impacter la durée de vie de l’assemblage. Ce travail vise à mettre en place un modèle de simulation de ce procédé dans le but d’optimiser les paramètres opératoires.Avant d’envisager un couplage thermomécanique, il convient de représenter convenablement les transferts thermiques au cours du soudage et en particulier l’apport de chaleur lié au procédé. Dans cette étude, on propose une source de chaleur prédictive simplifiée représentative des paramètres opératoires qui permet en particulier d’estimer les dimensions caractéristiques du cordon de soudure et de traduire fidèlement l’évolution thermique dans la pièce. Cette source est définie par un flux de chaleur homogène dépendant d’une puissance P, réparti sur un disque de rayon R, ces 2 paramètres numériques étant liés aux principaux paramètres opératoires de soudage que sont l’intensité I et la hauteur d’arc h.Une campagne d’essais expérimentaux dans laquelle on étudie les variations des dimensions de la Zone Fondue (ZF) pour des cas non pénétrants et pénétrants en fonction des paramètres opératoires (I, h) est présentée. Pour chaque essai, un couple de paramètres d’entrée de la source de chaleur (P, R) permettant de reproduire les dimensions du bain fondu est identifié. La confrontation des résultats obtenus numériquement et expérimentalement permet de mettre en place des relations entre les paramètres opératoires de soudage (I, h) et les paramètres numériques (P, R) conférant un caractère prédictif à la source de chaleur. Ce modèle de source a été validé pour différentes configurations de soudage en termes d’épaisseurs de tôles, de matériaux à assembler, de vitesses d’avance de la torche, ...Notre modèle thermique a ensuite servi de base pour la simulation thermomécanique du procédé. Le modèle est appliqué à l’assemblage de deux composants d’un turbomoteur en superalliage base Nickel. / Gas Tungsten Arc Welding (GTAW) is the most widely used welding process in aeronautics, due to its weld quality. During a welding operation, the thermal source induces thermal gradients causing strains and stresses that could affect assembly’s life duration. The aim of this study is to develop a numerical model of the welding process in order to get optimized process parameters.Before coupling thermal and mechanical phenomena, we must modelize heat transfers during welding. We propose a simplified heat source linked to the process parameters which enables to predict the main dimensions of the weld pool and the thermal evolution in the solid part. This source is defined by an homogeneous heat flux depending on a power P distributed in a R radius disk. These two parameters relate to process parameters, the arc height (h) and the current intensity I.Experiment tests was achieved to study the weld pool dimensions for both cases : incomplete penetration and full penetration weld. For each test, we identified the heat source parameters (P, R) which allow to obtain the experimental weld pool dimensions. The confrontation of numerical and experimental results enables to get links between the heat source parameters (P, R) and the welding parameters (I, h), producing a predictive heat source. The heat source reliability was verified taking into account several welding configurations with various superalloys sheet thickness, welding speed, materials.A coupled thermal-mechanical analysis, based on our thermal model, was applied to an industrial case: a nickel based superalloy components assembly of a gas turbine.

No description available.

Cette thèse présente la reconstruction de l’histoire tectono-thermique du massif varisque des Jebilet (Maroc) à fort potentiel minier, depuis son évolution pré-orogénique au Dévonien supérieur-Carbonifère inférieur jusqu’à sa structuration pendant l’orogénèse varisque-alléghanienne au Carbonifère supérieur-Permien inférieur. Pour répondre à cette problématique, ce travail s’organise autour de deux approches : (1) l’une métrologique appliquée à la géothermométrie Raman sur la matière carbonée (RSCM) et (2) l’autre intégrant une étude structurale, géochronologique et une analyse de la thermicité.L’approche métrologique a permis de valider l’applicabilité du géothermomètre RSCM (1) dans un contexte de métamorphisme polyphasé, (2) pour des roches carbonatées et des skarns des Jebilet et (3) de proposer un nouveau paramètre Raman RSA permettant de mieux préciser les températures supérieures à 500°C et d’étendre l’applicabilité de la méthode jusqu’à des températures maximales qui atteignent les 700°C.A partir de l’approche intégrée, trois épisodes tectono-thermiques ont été mis en évidence. Le premier épisode D₀ correspond à une tectonique extensive permettant l’ouverture du bassin des Jebilet au Dévonien supérieur-Carbonifère inférieur. Cette tectonique extensive est accompagnée par une anomalie thermique supérieure à 500°C déduites des mesures de géothermométrie RSCM (TRSCM) et par une importante activité magmatique bimodale et granodioritique datée dans ce travail entre 358 ± 7 et 336 ± 4 Ma. Au Carbonifère supérieur débute la phase compressive structurant le massif des Jebilet avec la mise en place de nappes superficielles au Namuro-Westphalien (D₁), suivie par la phase varisque majeure (D₂). L’analyse structurale a permis de montrer une évolution progressive du régime de déformation de D2 depuis une compression coaxiale à une transpression dextre compatible avec un raccourcissement horizontal WNW-ESE à NW-SE. D₂₁ est associée à deux événements thermiques, le premier syn-tectonique de moyenne température (300°<TRSCM<400°C), et le second syn- à post-tectonique de haute température (600°<TRSCM<660°C).Ce contexte tectono-thermique serait l’expression de processus géodynamiques impliquant à partir du Dévonien supérieur une délamination de la lithosphère rhéïque par « slab break-off » ou « slab roll-back » qui entrainerait (1) la remontée de courant asthénosphérique chaud, et (2) la rotation horaire de Gondwana et son amalgamation progressive avec Laurussia structurant au Carbonifère supérieur-Permien inférieur la chaine varisque-alléghanienne. / This thesis presents the reconstruction of the tectono-thermal history of the Paleozoic Jebilet massif (Morocco), from its pre-orogenic evolution at the Upper Devonian-Lower Carboniferous to its structuration during the variscan-alleghanian orogeny at the Upper Carboniferous-Lower Permian. To address this issue, this work is organized around two approaches: (1) one metrological applied to the Raman Spectroscopy of Carbonaceous Matterial (RSCM) and (2) the other integrating a structural and geochronological study and a thermicity analysis.The metrological approach allowed to validate the applicability of the RSCM geothermometer (1) in a context of polyphase metamorphism, (2) for carbonate rocks and skarns of Jebilet and (3) to propose a new parameter Raman RSA allowing to better specify temperatures above 500°C and extend the applicability of the method to maximum temperatures of up to 700°C.From the integrated approach, three tectono-thermal episodes were highlighted. The first episode D₀, corresponds to an extensive tectonic allowing the opening of the Jebilet basin at the Upper Devonian-Lower Carboniferous. This opening is accompanied by a HT thermal anomaly as shown by the important bimodal and granodioritic magmatic activity dated between 358 ± 7 Ma and 336 ± 4 Ma and the TRSCM higher than 500°C recorded by the rocks. During Upper Carboniferous, the compressive phase structuring the Jebilet massif begins with the emplacement of superficial nappes (D₁), followed by the variscan major phase (D2). Structural analysis showed a gradual evolution of D₂ deformation regime from coaxial compression to dextral transpression consistent with WNW-ESE to NW-SE horizontal shortening. D₂ is associated with two thermal events, the first is syn-tectonic with TRSCM between 300 and 400°C, and the second is syn- to post-tectonic with TRSCM between 600 and 660°C.This tectono-thermal context would be the expression of geodynamic processes involving from the Upper Devonian a delamination of the Rheic lithosphere by "slab break-off" or "slab roll-back" which would induce (1) the rise of hot asthenospheric current, and (2) the clockwise rotation of Gondwana and its gradual amalgamation with Laurussia structuring the variscan-alleghanian belt during the Upper Carboniferous-Lower Permian.