Le phénomène d’ilot de chaleur urbain « ICU » souvent observé dans les villes à forte densité urbaine, provoque des impacts négatifs surtout sur le confort thermique extérieur et sur la consommation énergétique des bâtiments. D’où l’importance d’intégrer des dispositifs d’atténuation de ce phénomène dans la conception des projets et des espaces urbains. Cette thèse vise à étudier les effets des différentes stratégies de limitation d’ICU sur les paramètres microclimatiques sous climat méditerranéen. Le cas étudié est un quartier compact de la ville libanaise Beyrouth qui est classifié comme un territoire artificialisé. Jusqu’à présent, peu de recherches microclimatiques ont été réalisées pour le cas Libanais et il y absence des codes et des mesures d’adaptation luttant contre l’ICU. Des simulations numériques sont réalisées à l’aide d’un outil microclimatique « ENVI-met », permettant d’identifier le potentiel rafraichissant de chaque stratégie proposée. Ces stratégies sont basées sur l’augmentation de l’albédo des revêtements du sol et de l’enveloppe des bâtiments, l’augmentation des espaces verts et des surfaces végétalisées, ainsi que sur la mise en place des sources d’eau comme les fontaines et les brumisateurs. Les charges de climatisation relatives à chaque mesure d’atténuation ont été évaluées à l’aide du couplage des données extraites avec ENVI-met avec le logiciel Hourly Analysis Program. Le travail de cette thèse a présenté la capacité des scenarios proposés à modifier les charges de climatisation sensibles ainsi que celles latentes. Le confort du piéton est aussi étudié en analysant l’indice de confort PET. / The urban heat island "UHI" phenomenon, frequently detected in cities with high urban density, leads to negative impacts especially on outdoor thermal comfort and buildings energy consumption. Accordingly, it is important to integrate mitigation measures into the design of projects and urban spaces. This thesis aims to study the effects of different UHI limitation strategies on microclimatic parameters in Mediterranean climate. The case of study is a com pact district of the Lebanese city Beirut which is classified as an artificial territory. Little microclimatic researches have been done for the Lebanese case and there is a lack of codes and adaptation measures to mitigate the effect of UHI. Numerical simulations are realized using "ENVI-met" software, to identify the cooling potential of each proposed strategy. These strategies are based on increasing the albedo of urban surfaces and buildings facades and roofs, increasing green spaces and vegetation surfaces, as well as the implementation of water sources such as fountains and water sprays. The cooling loads for each mitigation strategy were evaluated by linking ENVI-met results to the “Hourly Analysis Program” software. This thesis presented the capacity of the proposed scenarios to modify the sensible and latent cooling loads. The pedestrian comfort is also studied by analyzing the index of comfort PET.

Adulte ou pédiatrique, les tumeurs solides ont besoin d’oxygène et de nutriments pour se développer et métastaser. Leur apport est assuré par la néo-vascularisation tumorale issue d’un processus multifactoriel appelé l’angiogénèse. Son équilibre est maintenu par une balance entre facteurs pro- et anti-angiogéniques. Elle fait partie des principales cibles pour traiter les cancers et l’inhibition de la voie VEGF en est un facteur clé. Cependant, la réponse aux agents anti-angiogéniques a montré, malgré des résultats encourageants, un effet transitoire associé à l’apparition d’une résistance adaptative de la tumeur.Nous avons étudié l’inhibition de l’angiogénèse et les mécanismes potentiels d’échappement dans les tumeurs pédiatriques solides, et principalement dans le neuroblastome. Le neuroblastome est une tumeur originaire de la crête neurale et atteint généralement l’enfant jeune. Nous avons exploré l’effet anti-tumoral de l’inhibition sélective des récepteurs 1, 2, 3 du VEGF à l’aide de l’inhibiteur à tyrosine kinase axitinib dans divers modèles précliniques de neuroblastome. L’axitinib a montré une activité anti-tumorale modérée associée à une inhibition de la vascularisation. Néanmoins, après un traitement prolongé in vitro, les cellules tumorales IGR-N91-Luc deviennent résistantes à l’axitinib. Elles prolifèrent normalement mais secrètent de «l’ hepatocyte growth factor» (HGF) et activent la voie MAPK. In vivo, le traitement prolongé par axitinib entraîne le développement d’un phénotype plus agressif de la tumeur avec l’augmentation du nombre d’animaux présentant des métastases, associée à une activation de la voie SRC. Ceci nous a conduit à explorer l’effet d’une inhibition ciblant principalement VEGFR2 et MET (récepteur à l’HGF) avec le cabozantinib. Ainsi nous avons contrôlé le développement tumoral en inhibant la néo-vascularisation et l’activation de SRC, et induit la mort cellulaire dans le modèle orthotopique IGR-N91-Luc et inhibé le développement métastatique dans le modèle systémique IMR-32-Luc. Par ailleurs, nous avons étendu notre exploration à d’autres facteurs jouant un rôle dans l’angiogénèse comme FGFR ou PDGFR car ils représentent, comme MET, de puissants oncogènes. Pour cibler simultanément VEGFR et PDGFR, nous avons utilisé l’inhibiteur multi-kinase regorafenib. In vivo, à des doses bien tolérées qui permettent un traitement prolongé, le regorafenib a montré une activité anti-tumorale significative. Cet effet a été associé principalement à une forte inhibition de la vascularisation mais également à l’induction de la mort cellulaire. En élargissant notre étude à d’autres modèles de tumeurs pédiatriques, nous avons observé que son activité est indépendante du type histologique. Compte tenu du caractère oncogénique de PDGFR, nous avons évalué cet inhibiteur dans des modèles présentant une amplification du gène PDGFRA, qui entraine une surexpression et une activation forte du récepteur. Combiné avec des thérapies standards capables d’induire des dommages à l’ADN telles que l’irradiation ou l’irinotecan, l’effet du regorafenib a été potentialisé, notamment dans les modèles amplifiés pour le gène PDGFRA se traduisant par des régressions tumorales. Ces évaluations précliniques soutiennent le développement d’une nouvelle stratégie thérapeutique pour les enfants atteints de tumeurs solides. / Solid tumors either adult or pediatric need oxygen and nutrients to grow and metastasize. Their input is provided by tumor neovascularization after a multifactorial process called angiogenesis. Balance is maintained by equilibrium between pro and anti-angiogenic factors. It is one of the main targets for treating cancers and the inhibition of the VEGF pathway is a key factor. However, despite encouraging results, the response to anti-angiogenic agents showed a transient effect associated with the development of an adaptive tumor resistance. We studied the inhibition of angiogenesis and potential escape mechanisms in solid pediatric tumors, mainly in neuroblastoma. Neuroblastoma is a solid tumor derived from the neural crest and it usually affects childhood. We investigated the anti-tumor effect of selective inhibition of VEGF receptors 1, 2, 3 using the tyrosine kinase inhibitor axitinib in various preclinical neuroblastoma l models. Axitinib showed a moderate anti-tumor activity associated with the inhibition of vascularization. However, after prolonged treatment in vitro, tumor cells IGR-N91-Luc become resistant to axitinib. They proliferate normally but secrete the "hepatocyte growth factor" (HGF) and activate the MAPK pathway. In vivo, prolonged treatment by axitinib results in the development of a more aggressive tumor phenotype with an increase in the number of animals exhibiting metastases associated with an activation of SRC signaling. This led us to explore the effect of inhibiting concomitant VEGFR2 and MET (HGF receptor), main cabozantinib targets. So we stabilized tumor growth by inhibiting the neovascularization and activation of SRC, induced cell death in the orthotopic model IGR-N91-Luc and inhibited metastatic development in the IMR-32-Luc systemic model. In addition, we extended our exploration of other factors that play a role in angiogenesis like FGFR or PDGFR because they represent, like MET, powerful oncogenes. To simultaneously target VEGFR and PDGFR, we used the multi-kinase inhibitor regorafenib. In vivo, at well-tolerated doses that allow prolonged treatment, regorafenib showed significant anti-tumor activity. This effect was mainly associated with a strong inhibition of vascularization, but also (with) induction of cell death. By expanding our study to other models of pediatric tumors, we observed that its activity was independent of histologic type. Given the oncogenic character of PDGFR, we evaluated the inhibitor in models which present a PDGFRA gene amplification, which results in a strong activation of the receptor. Combined with standard therapies that can induce DNA damages such as irinotecan or radiation, the effect of regorafenib was potentiated, mainly in PDGFRA gene amplified models, where tumor regressions were obtained. These preclinical evaluations support the development of a new therapeutic strategy for children with solid tumors.

Muitos são os benefícios provenientes da arborização de vias públicas, como aumento da vida útil do asfalto por meio do sombreamento, filtragem de poluentes, absorção de CO2, interceptação da água da chuva e da radiação solar e mitigação de ilhas de calor; porém, por questões culturais, é considerada muitas vezes pela população como algo negativo, cujas folhas entopem calhas, raízes destroem calçadas, troncos e folhas atrapalham fiação elétrica e, principalmente, elas estão susceptíveis às quedas. A pesquisa teve como objetivo estudar o comportamento das quedas de árvores no município de Piracicaba/SP, Brasil, com atenção especial ao regime de ventos na cidade, baseado em dados fornecidos pelo Corpo de Bombeiros de Piracicaba, Secretaria de Defesa do Meio Ambiente de Piracicaba (SEDEMA) e Estação Meteorológica da Escola Superior de Agricultura \"Luiz de Queiroz\" (ESALQ). De caráter inédito, o principal resultado foi a relação direta entre quedas e zonas urbanizadas, que, em constantes alterações no uso do solo, acabam por danificar a sustentação das árvores (raízes), fato justificado pela alta concentração de quedas na parte central (36,7%), com destaque para as estações da primavera e do verão, ou seja, ventos e chuvas, na qual, juntas, somaram 78,0% do total. O período de retorno esperado para ventos superiores a 75 km h-1, classificados como temporais na Escala de Vento de Beaufort, foi de 2,8 eventos por ano. Enquanto verificou-se o predomínio de ventos alísios de sudeste, pertencentes ao quarto quadrante, a direção das rajadas de vento teve maior variação e, assim, com predomínio daqueles ventos, é recomendável instalações de parques industriais nas zonas norte, noroeste e oeste, haja vista a importância de evitar que os poluentes adentrem a cidade. As espécies de maior vulnerabilidade foram: Pachira aquatica Aubl. (monguba), Handroanthus sp. (ipê roxo) e Tipuana tipu (Benth.) Kuntze (tipuana). Por meio de simulação microclimática computacional, utilizando o programa ENVI-met versão 3.1, em dois estudos de caso, sendo um em bairro residencial e outro na Praça José Bonifácio, foi possível identificar locais de maior atenção quanto às quedas de árvores, em função da rugosidade do local, capaz de alterar a velocidade e a direção do vento. / There are many benefits from public roads afforestation, such as longer pavement life through shading, filtering pollutants, CO2 absorption, intercepting rainfall and solar radiation and mitigating heat islands; however, due cultural issues, is often regarded by the population as something negative, whose leaves clog gutters, roots destroy sidewalks, stems and leaves disrupt electrical wiring and, mainly, they are susceptible to falls. The research aimed to study the behavior of falling trees in Piracicaba/SP, Brazil, with special attention to the wind regime in the city, based on data provided by the Piracicaba Fire Department, Secretariat of Defense of the Environment of Piracicaba (SEDEMA) and Meteorological Station Luiz de Queiroz College of Agriculture (ESALQ). From unedited character, the main result was the direct relationship between falls and urbanized areas, which, in constant changes in land use, end up damaging the support of trees (roots), a fact explained by the high concentration of falls in the central part (36.7%), highlighted to the spring and summer seasons, i.e., winds and rains, which, together, totaling 78.0% of the total cases. The payback period expected to winds who exceeding 75 km h-1, classified as storms in the Beaufort Wind Scale, was 2.8 events per year. While there was a predominance of trade winds from the Southeast, belonging to the fourth quadrant, the direction of the gusts of wind had greater variation and, thus, with those predominant winds, it recommend installation of industrial parks in North, Northwest and West areas, since the importance of avoiding that pollutants enter into the city. The most vulnerable species were: Pachira aquatica Aubl. (Guiana Chestnut), Handroanthus sp. (Purple Ipe) and Tipuana tipu (Benth.) Kuntze (Tipuana). Through computational microclimate simulation, using the software ENVI-met version 3.1, in two case studies, being one in a residential area and another in the José Bonifácio Square, it was possible to identify locals of more attention as the falling trees, based on the local roughness, able to change the speed and direction of the wind.

A presente pesquisa trata da influência da verticalização na sensação térmica urbana, dentro de um contexto de diretrizes de compactação das cidades, aplicada à cidade de Maringá / PR, cujo clima é subtropical úmido. Pretende avaliar se o aumento do gabarito dos edifícios da região apontada, realizado de modo a respeitar o parcelamento e o uso e ocupação do solo, interfere no conforto térmico urbano, mediante a verificação do índice de temperatura fisiológica equivalente (PET). Seu desenvolvimento é realizado com base na análise de resultados obtidos por meio de ferramentas computacionais, especialmente o software ENVI-met, seguindo as seguintes etapas: 1. Histórico Urbanístico, em que se avalia o plano inicial da cidade e o seu perfil atual; 2. Caracterização Climática, na qual se elabora o arquivo climático do município, sua carta de ventos, bem como todos os tratamentos necessários para a aplicação do software; 3. Modelagem e Simulação, em que se define e constrói os cenários, para posterior simulação; 4. Avaliação Ambiental, em que se analisa a sensação térmica dos resultados da simulação. Por fim, mediante a avaliação dos resultados obtidos, demonstra-se que a verticalização, em climas subtropicais úmidos, pode ser utilizada como atenuação da sensação térmica. / This research deals with the influence of verticalization on urban thermal sensation, within a context of city compaction guidelines, applied to the city of Maringá / PR, whose climate is humid subtropical. The objective of this study is to evaluate whether the increase in the model of the buildings in the mentioned region, in order to respect the parceling and the use and occupation of the soil, interferes with the urban thermal comfort by checking the equivalent Physiological Temperature Index (PET). Its development will be carried out based on the analysis of results obtained through computational tools, especially the ENVI-met software, following the following steps: 1. Urban History, in which the initial plan of the city and its current profile will be evaluated; 2. Climatic Characterization, in which the climatic archive of the municipality, its chart of winds, as well as all the necessary treatments for the application of the software will be elaborated; 3. Modeling and Simulation, in which the scenarios will be defined and constructed, for later simulation; 4. Environmental Assessment, in which the thermal sensation of the results of the simulation will be analyzed. Finally, by means of the evaluation of the obtained results, it will be shown that the verticalization, in humid subtropical climates, can be used as attenuation of the thermal sensation.

Met und der korrespondierende Ligand HGF/SF sind im hyperproliferativen Epithelium von Hautwunden exprimiert. Aus diesem Grund ist es wahrscheinlich, dass der Rezeptor und sein Ligand in autokriner Weise wechselwirken und wichtige Funktionen für den Heilungsprozess der Haut besitzen. Unter Verwendung der Keratin 14 Cre-Rekombinase konnte ein „Knockout“ des Met-Rezeptors spezifisch in der Epidermis erzielt werden. In der Tat zeigten die Ergebnisse, dass Met für die Re-epithelisierung in Wundschlussprozessen essentiell ist, da in den an der Wundheilung beteiligten Keratinozyten keine Rekombination des Met-Gens stattgefunden hat. In Met-Mausmutanten war der Wundschlussprozess verlangsamt, denn er erfolgte ausschließlich durch wenige Keratinozyten, in denen die Cre-Rekombinase keine Rekombination bewirkte. Met konnte als erstes Gen identifiziert werden, das absolut erforderlich für Re epithelisierungsprozesse von Wunden ist. Diese Arbeit trägt daher wesentlich zum Verständnis der Regulation von Wundheilungsprozessen bei. / Met and its ligand, HGF/SF are expressed in the hyperproliferative epithelium of the wound. This suggests that receptor and ligand may act in an autocrine manner to promote wound healing in the skin. Using Keratin 14 cre recombinase, Met receptor was specifically knockout in the epidermis. In this way, it was demonstrated that Met receptor is essential for wound healing process and that keratinocytes, which contributed to the wound closure were Met-postitive. In the Met mutant mice, wound closure was slightly attenuated, but occurred exclusively by a few keratinocytes that had escaped recombination. Met is therefore the fist gene, which is absolutely required for re-epithelialization of the wound. This finding is fundamental for understanding the regulation of wound healing process.

Muitos são os benefícios provenientes da arborização de vias públicas, como aumento da vida útil do asfalto por meio do sombreamento, filtragem de poluentes, absorção de CO2, interceptação da água da chuva e da radiação solar e mitigação de ilhas de calor; porém, por questões culturais, é considerada muitas vezes pela população como algo negativo, cujas folhas entopem calhas, raízes destroem calçadas, troncos e folhas atrapalham fiação elétrica e, principalmente, elas estão susceptíveis às quedas. A pesquisa teve como objetivo estudar o comportamento das quedas de árvores no município de Piracicaba/SP, Brasil, com atenção especial ao regime de ventos na cidade, baseado em dados fornecidos pelo Corpo de Bombeiros de Piracicaba, Secretaria de Defesa do Meio Ambiente de Piracicaba (SEDEMA) e Estação Meteorológica da Escola Superior de Agricultura \"Luiz de Queiroz\" (ESALQ). De caráter inédito, o principal resultado foi a relação direta entre quedas e zonas urbanizadas, que, em constantes alterações no uso do solo, acabam por danificar a sustentação das árvores (raízes), fato justificado pela alta concentração de quedas na parte central (36,7%), com destaque para as estações da primavera e do verão, ou seja, ventos e chuvas, na qual, juntas, somaram 78,0% do total. O período de retorno esperado para ventos superiores a 75 km h-1, classificados como temporais na Escala de Vento de Beaufort, foi de 2,8 eventos por ano. Enquanto verificou-se o predomínio de ventos alísios de sudeste, pertencentes ao quarto quadrante, a direção das rajadas de vento teve maior variação e, assim, com predomínio daqueles ventos, é recomendável instalações de parques industriais nas zonas norte, noroeste e oeste, haja vista a importância de evitar que os poluentes adentrem a cidade. As espécies de maior vulnerabilidade foram: Pachira aquatica Aubl. (monguba), Handroanthus sp. (ipê roxo) e Tipuana tipu (Benth.) Kuntze (tipuana). Por meio de simulação microclimática computacional, utilizando o programa ENVI-met versão 3.1, em dois estudos de caso, sendo um em bairro residencial e outro na Praça José Bonifácio, foi possível identificar locais de maior atenção quanto às quedas de árvores, em função da rugosidade do local, capaz de alterar a velocidade e a direção do vento. / There are many benefits from public roads afforestation, such as longer pavement life through shading, filtering pollutants, CO2 absorption, intercepting rainfall and solar radiation and mitigating heat islands; however, due cultural issues, is often regarded by the population as something negative, whose leaves clog gutters, roots destroy sidewalks, stems and leaves disrupt electrical wiring and, mainly, they are susceptible to falls. The research aimed to study the behavior of falling trees in Piracicaba/SP, Brazil, with special attention to the wind regime in the city, based on data provided by the Piracicaba Fire Department, Secretariat of Defense of the Environment of Piracicaba (SEDEMA) and Meteorological Station Luiz de Queiroz College of Agriculture (ESALQ). From unedited character, the main result was the direct relationship between falls and urbanized areas, which, in constant changes in land use, end up damaging the support of trees (roots), a fact explained by the high concentration of falls in the central part (36.7%), highlighted to the spring and summer seasons, i.e., winds and rains, which, together, totaling 78.0% of the total cases. The payback period expected to winds who exceeding 75 km h-1, classified as storms in the Beaufort Wind Scale, was 2.8 events per year. While there was a predominance of trade winds from the Southeast, belonging to the fourth quadrant, the direction of the gusts of wind had greater variation and, thus, with those predominant winds, it recommend installation of industrial parks in North, Northwest and West areas, since the importance of avoiding that pollutants enter into the city. The most vulnerable species were: Pachira aquatica Aubl. (Guiana Chestnut), Handroanthus sp. (Purple Ipe) and Tipuana tipu (Benth.) Kuntze (Tipuana). Through computational microclimate simulation, using the software ENVI-met version 3.1, in two case studies, being one in a residential area and another in the José Bonifácio Square, it was possible to identify locals of more attention as the falling trees, based on the local roughness, able to change the speed and direction of the wind.

Les Carcinomes Papillaires du Rein (pRCC) représentent la seconde forme histologique de cancers du rein . Ils correspondent à une entité hétérogène de tumeurs subdivisées en type I et type II sur leurs caractéristiques anatomopathologiques. Leur pronostic au stade métastatique est inferieur à celui des carcinomes à cellules claires. Les caractéristiques biologiques des pRCC sont mal connues et n’ont pas permis de développer jusqu'à ce jour de thérapeutiques spécifiques.Ce travail propose, en première partie, une synthèse des données disponibles biologiques, anatomo-pathologiques, thérapeutiques et pronostiques des pRCC. Cette synthèse a fait l’objet d’une publication. ( Albiges et al. The Oncologist 2012)Le second volet est dédié à l’analyse de la place du proto-oncogène MET au sein des pRCC de type I et II et plus particulièrement les différentes modalités d’activation de ce gène. Cette analyse (i) caractérise les anomalies quantitatives de l’ADN du gène MET (CGH array pour les pRCC de type II et CGMA pour les pRCC de type I) et leur corrélation au niveau d’expression génique; (ii) recherche l’existence de mutations activatrices du domaine tyrosine kinase par séquençage du gène MET chez les pRCC de type I; et (iii) analyse également les niveaux d’expression du ligand et des co-activateurs de ce récepteur MET. Ces résultats sont en cours de publication (Albiges et al. Clinical Cancer Research)Le troisième et dernier volet de ce travail vise à identifier des pistes biologiques propres aux pRCC par l’analyses de sous groupes distinguable en termes de profils d’expression génique et surtout par l’analyses des anomalies de l’ADN identifiées par CGH array des pRCC de type II, couplées aux données de transcriptome. / Papillary renal cell carcinomas (pRCC) are the second most common form of Renal Carcinomas and belongs to the non clear cell carcinomas family. This tumour type is an heterogeneous group of tumours usually subdivided in type I and type II according to pathological features. The prognosis of pRCC in the metastatic setting is worse to clear cell carcinoma’s prognosis. Biological characteristics of pRCC are poorly known and did not allow the development of specific targeted therapies.This work first presents a synthesis of published data regarding biology, pathology, therapeutics and prognosis of pRCC. This review has been published. (Albiges et al. The Oncologist 2012)Second part is dedicated to the analysis of MET proto-oncogene across pRCC. The main focus is to assess MET activation drivers. This analysis (i) characterises MET gene DNA copy number alterations (CGH array for type II pRCC and CGMA approach for Type I pRCC) and their correlation with gene expression profiling; (ii) assess activating mutations within the tyrosine kinase of MET gene in the type I pRCC; and (iii) investigate expression level of ligand and co-activators of MET receptor. This analysis is under publication. (Albiges et al. Clinical Cancer Research)Third and last part of this work aims at identifing new biological pathway specific to pRCC using clustering of gene expression profiling and DNA abnormalities assessed by CGHarray inthe type II pRCC subtypes with matching gene expression data.

Ce travail porte sur l’étude des phénomènes induits par implantation d’hydrogène et/ou d’hélium dans le silicium monocristallin. Le cloquage et l’exfoliation dus à la coimplantation d’hélium et d’hydrogène ont été étudiés en fonction des paramètres d’implantation (énergie, fluence, courant, rapport H/He) et des conditions de recuit. Un comportement de type fenêtre à été observé dont le maximum de surface exfoliée dépend uniquement de la fluence. Deux mécanismes d’exfoliation liés aux régimes de fluence ont été identifiés et discutés. D’autre part, la microstructure des échantillons a été étudié par MET, et les déformations ont été mesurées par diffraction des Rayons X. Un modèle décrivant la distribution des contraintes dans le substrat implanté a été proposé. Le phénomène de delamination des substrats qui apparaît pour des conditions particulières d’implantation a également été étudié, comparé aux phénomènes de cloquage et exfoliation, et expliqué en utilisant des concepts de la mécanique de la fracture. Enfin, l’interaction élastique entre précipités d’He et d’H a été étudiée pour des profils d’implantation superposés et décalés. Dans ce dernier cas, nous avons montré que le champ de contraintes générées par les plaquettes d’hélium en surpression pouvait être utilisé comme source locale de contraintes pour contrôler la formation et la croissance de plaquettes d’hydrogène. Afin d’interpréter nos résultats expérimentaux, nous avons développé un modèle basé sur l’interaction élastique pour la nucléation des précipités dans un solide semi-infini. / The present work relates an investigation of H2 + and He+ coimplanted (001)-Si substrates. The phenomena of blistering and exfoliation were studied by SEM as a function of the implantation parameters (energy, fluence, current and H/He ration) and annealing protocol. A window behavior as function of the implanted fluence was observed and two distinct fluence dependents mechanisms of exfoliation were indentified and discussed. The microstructure of the implanted samples was studied using TEM and related to ballistic effects and stress-strain dependent interactions. The strain was measured using DRX and a model to describe the stress-strain distribution into the implanted layer is developed. A new phenomenon of delamination of thin layer from implanted Si substrates was observed to emerge from particular implantation conditions. The behavior was studied and explained using fracture mechanics concepts and contrasted to blistering/exfoliation processes. Finally, the elastic interaction between He and H plate-like precipitates giving rise to arranged nanostructure was demonstrated and studied using TEM. An elasticity based model was developed to understand the behavior. The result set the basis for further developments of nanostructures within a crystalline matrix by manipulating preferential orientations of precipitates in nanometric scale.

Made available in DSpace on 2014-12-17T14:06:53Z (GMT). No. of bitstreams: 1 ClawsioRCS_DISSERT.pdf: 4688648 bytes, checksum: dd0d723d2cc3d7de35608b8ed730a95b (MD5) Previous issue date: 2010-03-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The cells unitaria of the solid oxide fuel cell are separated by means of interconnects, which serve as electrical contact between the cells. Lanthanum Chromite (LaCrO3) has been the most common material used as interconnect in solid oxide fuel cells. Reducing the operating temperature around 800 ? C of cells to solid oxide fuel make possibilite the use of metallic interconnects as an alternative to ceramic LaCrO3. Metallic interconnects have advantages over ceramic interconnects such as high thermal conductivity, electricity, good ductility, low cost, good physical and mechanical properties. In this work evaluate the thermo-mechanical properties of the metallic substrate and coated metallic substrate with the ceramic LaCrO3 film via spray-pyrolysis, in order to demonstrate the feasibility of using this material as a component of a fuel cell solid oxide. The materials were characterized by X-ray diffraction, oxidation behavior, mechanical strength, optical microscopy (OM) and scanning electron microscopy (SEM). The X-ray diffraction proved the formation phase of the LaCrO3 on the metallic substrate and the identification of the phases formed after the oxidative test and mechanical strength at high temperature. The oxidation behavior showed the increased oxidation resistance of the coated metallic substrate. It was noted that the mechanical resistance to bending of the coated metallic substrate only increases at room temperature. The optical microscopy (OM) has provided an assessment of both the metallic substrate and the LaCrO3 film deposited on the metal substrate that, in comparison with the micrographs obtained from SEM. The SEM one proved the formation of Cr2O3 layer on the metallic substrate and stability of LaCrO3 film after oxidative test, it can also observe the displacement of the ceramic LaCrO3 film after of mechanical testing and mapping of the main elements as chromium, manganese, oxygen, lanthanum in samples after the thermo-mechanical tests. / As pilhas unit?rias de uma pilha a combust?vel de ?xido s?lido s?o separadas por meio de interconectores, que servem como contato el?trico entre as pilhas. A cromita de lant?nio (LaCrO3) tem sido o material mais utilizado como interconector nas pilhas a combust?vel de ?xido s?lido. A redu??o da temperatura de opera??o em torno de 800 ?C das pilhas a combust?vel de ?xido s?lido, tornou poss?vel o uso de interconectores met?licos como alternativa aos LaCrO3 cer?micos. Esses materiais apresentam vantagens em rela??o aos interconectores cer?micos tais como: alta condutividade t?rmica, el?trica, boa ductilidade, baixo custo, boas propriedades f?sicas e mec?nicas. Neste trabalho foram avaliadas as propriedades termomec?nicas do substrato met?lico e substrato met?lico recoberto com o filme de LaCrO3 via spray-pir?lise, com o objetivo de demonstrar a viabilidade da utiliza??o deste materiais como componente de uma pilha a combust?vel de ?xido s?lido. Os materiais foram caracterizados por meio de difra??o de raios-X, comportamento oxidativo, resist?ncia mec?nica, microscopia ?ptica e microscopia eletr?nica de varredura (MEV). A difra??o de raios-X comprovou a forma??o da fase LaCrO3 sobre o substrato met?lico e a identifica??o das fases formadas ap?s o ensaio oxidativo e resist?ncia mec?nica a alta temperatura.O comportamento oxidativo evidenciou o aumento da resist?ncia a oxida??o do substrato met?lico recoberto. Na resist?ncia mec?nica a flex?o do substrato met?lico recoberto, notou-se o aumento apenas na temperatura ambiente. A microscopia ?ptica (MO) fez uma avalia??o pr?via tanto do substrato met?lico e do filme de LaCrO3 recoberto sobre o substrato met?lico,que em compara??o com as micrografias obtidas por MEV. Com aux?lio do MEV comprovou a forma??o da camada de Cr2O3 sobre o substrato met?lico e a estabilidade do filme de LaCrO3 ap?s o ensaio oxidativo. Observando tamb?m o descolamento do filme de LaCrO3 ap?s ensaio mec?nico e a distribui??o dos principais elementos como: cromo, mangan?s, oxig?nio, lant?nio nas amostras que foram submetidas aos ensaios termo-mec?nicos

Ce travail porte sur l’étude des phénomènes induits par implantation d’hydrogène et/ou d’hélium dans le silicium monocristallin. Le cloquage et l’exfoliation dus à la coimplantation d’hélium et d’hydrogène ont été étudiés en fonction des paramètres d’implantation (énergie, fluence, courant, rapport H/He) et des conditions de recuit. Un comportement de type fenêtre à été observé dont le maximum de surface exfoliée dépend uniquement de la fluence. Deux mécanismes d’exfoliation liés aux régimes de fluence ont été identifiés et discutés. D’autre part, la microstructure des échantillons a été étudié par MET, et les déformations ont été mesurées par diffraction des Rayons X. Un modèle décrivant la distribution des contraintes dans le substrat implanté a été proposé. Le phénomène de delamination des substrats qui apparaît pour des conditions particulières d’implantation a également été étudié, comparé aux phénomènes de cloquage et exfoliation, et expliqué en utilisant des concepts de la mécanique de la fracture. Enfin, l’interaction élastique entre précipités d’He et d’H a été étudiée pour des profils d’implantation superposés et décalés. Dans ce dernier cas, nous avons montré que le champ de contraintes générées par les plaquettes d’hélium en surpression pouvait être utilisé comme source locale de contraintes pour contrôler la formation et la croissance de plaquettes d’hydrogène. Afin d’interpréter nos résultats expérimentaux, nous avons développé un modèle basé sur l’interaction élastique pour la nucléation des précipités dans un solide semi-infini. / The present work relates an investigation of H2 + and He+ coimplanted (001)-Si substrates. The phenomena of blistering and exfoliation were studied by SEM as a function of the implantation parameters (energy, fluence, current and H/He ration) and annealing protocol. A window behavior as function of the implanted fluence was observed and two distinct fluence dependents mechanisms of exfoliation were indentified and discussed. The microstructure of the implanted samples was studied using TEM and related to ballistic effects and stress-strain dependent interactions. The strain was measured using DRX and a model to describe the stress-strain distribution into the implanted layer is developed. A new phenomenon of delamination of thin layer from implanted Si substrates was observed to emerge from particular implantation conditions. The behavior was studied and explained using fracture mechanics concepts and contrasted to blistering/exfoliation processes. Finally, the elastic interaction between He and H plate-like precipitates giving rise to arranged nanostructure was demonstrated and studied using TEM. An elasticity based model was developed to understand the behavior. The result set the basis for further developments of nanostructures within a crystalline matrix by manipulating preferential orientations of precipitates in nanometric scale.