Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-11T06:47:59Z No. of bitstreams: 2 Dissertação - Pérola Morais Calil - 2009.pdf: 3106835 bytes, checksum: e5ae60613d54ee5455d5dab6bcb6f09e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-11T06:50:21Z (GMT) No. of bitstreams: 2 Dissertação - Pérola Morais Calil - 2009.pdf: 3106835 bytes, checksum: e5ae60613d54ee5455d5dab6bcb6f09e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-11T06:50:21Z (GMT). No. of bitstreams: 2 Dissertação - Pérola Morais Calil - 2009.pdf: 3106835 bytes, checksum: e5ae60613d54ee5455d5dab6bcb6f09e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2009-08-28 / Planning and environmental management are activities that aim to control and suitable land use for maximum agricultural yield purposes, through a powerful operating system, capable of sustaining human activities with a minimum of disturbances on physical, ecological and social processes. To ensure the rational use of natural resources, soil properties need to be taken in account, as well terrain steepness and water dynamics, since they inform about cropping intensity and agronomic practices to be applied to soils, in order to avoid exhaustion of productive capacity caused by erosion. This work aimed to assess morphometric attributes related to soil distribution over the landscape and suggest the land use potential, based on the roughness coefficient in the Alto Meia Ponte River basin (Goiás, Brazil). Among the studied variables, morphometric attributes, associated to roughness coefficient, proved to be a valuable tool for the definition of land use potentialities in the diagnosis phase. They are low cost procedures, providing suitable information about water dynamics and, or, hydrologic behavior, as well the ease of gathering information. The use of roughness coefficient resulted in initial indication of the watershed for livestock and reforestation. The intersection of roughness coefficient and soil surveys data, associated with average land slopes, allowed to discriminate more areas suited to farming activities and those more vulnerable to environmental degradation. The refinement of information enabled the increase in areas liable to agricultural use, provided that conservative and preventive measures of soil degradation are taken. / O planejamento e o manejo ambiental são atividades que visam ao controle e adequação do uso das terras com a finalidade de maximizar a produtividade agrícola por meio de um sistema de exploração eficiente capaz de sustentar as atividades humanas com um mínimo de distúrbios nos processos físicos, ecológicos e sociais. Para garantir o uso racional dos recursos naturais devem-se considerar as características das propriedades do solo, a declividade do terreno e a dinâmica das águas, pois indicam a intensidade de cultivo e o manejo a ser aplicado ao solo para que não haja exaustão da capacidade produtiva em decorrência da erosão. O objetivo desse trabalho foi avaliar os atributos morfométricos em relação à distribuição dos solos na paisagem e sugerir o potencial de uso da terra com base no coeficiente de rugosidade na bacia hidrográfica do alto rio Meia Ponte, Goiás. Dentre as variáveis estudadas, os atributos morfométricos associados ao coeficiente de rugosidade, revelaram-se de grande valor na definição da potencialidade de uso da terra, na fase de prédiagnóstico. São procedimentos de baixo custo, fornecendo informações satisfatórias sobre a dinâmica hídrica e, ou, o comportamento hidrológico, bem como a facilidade na obtenção de informações. O coeficiente de rugosidade resultou na indicação inicial do uso da bacia para pecuária e reflorestamento.Com o cruzamento dos dados do coeficiente de rugosidade e de levantamentos de solos, associados às declividades médias, foi possível discriminar mais áreas aptas às diferentes atividades (agropecuárias) e aquelas mais vulneráveis à degradação ambiental. O refinamento das informações possibilitou o aumento das áreas aptas à agricultura, desde que sejam tomadas medidas conservacionistas, preventivas da degradação do solo.

O objetivo deste estudo foi comparar a resistência de união e a interface de falha da colagem de braquetes colados pela técnica indireta após o condicionamento do esmalte com jato de óxido de alumínio de 27, 50 e 90 m seguido da aplicação de ácido fosfórico a 37%; e avaliar quantitativa e qualitativamente as alterações da superfície do esmalte após os diferentes tipos de condicionamento. A amostra foi constituída por 104 pré-molares superiores. Na primeira parte da pesquisa 80 dentes foram divididos aleatoriamente em 4 grupos (n=20) que receberam diferentes condicionamentos das faces linguais: G1 (controle)- ácido fosfórico a 37%; G2, G3 e G4- jato de óxido de alumínio de 27, 50 e 90 m, respectivamente, antes da aplicação de ácido fosfórico. Braquetes linguais foram colados indiretamente com o mesmo material e metodologia nos 4 grupos. A força máxima de cisalhamento requerida para descolar os braquetes foi determinada por meio de uma máquina de ensaios mecânicos universal, e a interface de falha na colagem, por meio do Índice de Resina Remanescente (ARI). Para a avaliação quantitativa dos efeitos provocados no esmalte pelos diferentes condicionamentos, 20 dentes foram divididos aleatoriamente em 4 grupos, e suas faces linguais foram condicionadas de acordo com o protocolo proposto anteriormente. A rugosidade do esmalte (Ra) antes e após o seu condicionamento foi determinada por meio de um microscópio a laser confocal. Na avaliação qualitativa foram utilizados 4 dentes, que foram condicionados segundo protocolo descrito anteriormente. O teste ANOVA de um critério foi utilizado para comparar a resistência adesiva e o incremento de rugosidade entre os grupos. As diferenças entre as pontuações do ARI foram avaliadas com o teste de Kruskal-Wallis. Foi adotado nível de significância de 5% em todas as avaliações estatísticas. Não foram observadas diferenças estatisticamente significantes entre os quatro tipos de condicionamento de esmalte quando avaliou-se as médias de resistência de união e o incremento de rugosidade. Também não foram verificadas diferenças estatisticamente significativas entre as pontuações do ARI. O resultado da avaliação qualitativa evidenciou padrões diferentes de condicionamento entre o esmalte condicionado com ácido fosfórico e o esmalte condicionado com óxido de alumínio associado ao ácido. No esmalte condicionado com ácido, observaram-se leves irregularidades correspondentes com o padrão tipo III de Silverstone; enquanto no esmalte condicionado com jato de óxido de alumínio de 27, 50 e 90 m mais ácido fosfórico verificaram-se padrões similares de condicionamento, com superfícies de textura áspera bastante uniforme, presença de múltiplas elevações com diferentes alturas e bordas arredondadas, semelhantes ao padrão tipo II de Silverstone. Assim, concluiu-se que o condicionamento do esmalte com óxido de alumínio associado ao ácido não incrementou a resistência de união de braquetes colados indiretamente, não modificou a quantidade de resina remanescente, nem aumentou a rugosidade do esmalte. No entanto, produz um padrão de condicionamento diferente ao obtido com o ácido. / The purpose of this study was to compare the bond strength and the bond failure location of indirectly bonded brackets after enamel conditioning with 27, 50 and 90 m aluminum oxide followed by application of 37% phosphoric acid; and to analyze quantitatively and qualitatively the alterations on the enamel surface after the different conditionings. The sample consisted of 104 superior premolars. In the first stage of this research, 80 teeth were randomly divided into 4 groups (n=20) that received different conditionings at the lingual faces: G1 (control)- 37% phosphoric acid, G2, G3 and G4- 27, 50 and 90 m aluminum oxide, respectively, before applying phosphoric acid. The lingual brackets were indirectly bonded using the same material and methodology in the 4 groups. The maximum shear bond strength required to debond the brackets was determined using a mechanical testing machine, and the bond failure location through the Adhesive Remnant Index (ARI). For the quantitative analysis of the effects caused in the enamel due to the different conditionings, 20 teeth were randomly divided into 4 groups, and their lingual faces were conditioned according to the previously described protocol. The enamel roughness (Ra) before and after conditioning was measured using a confocal laser scanning microscope. In the qualitative analysis 4 teeth that were conditioned according to the previously described protocol were used. One-way ANOVA analysis was used to compare the bond strength and the roughness increment between the groups. The differences among the ARI scores were analyzed with the Kruskal-Wallis test. A 5% significance level was adopted for all statistical analysis. No statistical differences were observed among the 4 types of enamel conditionings when the mean shear bond strength and roughness increase were compared. There were not also statistically significant differences between the ARI scores. The results of the qualitative analysis showed different conditioning patterns between the enamel prepared with phosphoric acid and the enamel treated with aluminum oxide associated to phosphoric acid. In the acid-etching enamel, slight irregularities corresponding to Silverstones type III pattern were found; while in the enamel conditioned with aluminum oxide of 27, 50 and 90 m followed by phosphoric acid, similar conditioning patterns were found, with rough surfaces highly uniform, presence of multiple elevations of different heights and rounded edges, similar to Silverstones type II pattern. In conclusion, the enamel conditioning with aluminum oxide associated to phosphoric acid did not increase the bond strength of indirectly bonded brackets; it did not modify the quantity of remnant resin nor increased the enamel roughness. However, it produced a conditioning pattern different to the one obtained with acid.

O objetivo deste estudo foi avaliar o efeito da simulação de condições de inumação e afogamento sobre estabilidade de cor, rugosidade de superfície e microdureza de resina composta (RC), cimento de ionômero de vidro (CIV) e amálgama de prata (AM), visando fornecer elementos para diferenciação de materiais estéticos e estimativa do tempo de submissão aos agentes. Foram obtidos 60 incisivos bovinos, que receberam preparos cavitários (6 x 6 mm e 2 mm de profundidade) e foram restaurados com RC FiltekMR Z250 XT (3M ESPE®), CIV KetacTM Fil Plus (3M ESPE®) e AM em cápsulas gs-80 (SDI®). Realizaram-se as primeiras leituras, que se constituíram no baseline, de: cor, (Espectrofotômetro VITA® Easyshade), rugosidade de superfície (Rugosímetro Mitutoyo® Surftest SJ-201P) e microdureza Knoop (microdurômetro Shimadzu® Micro Hardness Tester HMV-2). Em seguida, as amostras foram separadas em dois grupos de 30 (n=10), de acordo com as condições a que foram submetidas: simulação de condições de inumação e de afogamento, por 1, 3 e 6 meses, após os quais novas leituras foram realizadas. Os valores de alteração de cor (&Delta;E, &Delta;L, &Delta;a e &Delta;b) e demais propriedades dos materiais estéticos foram submetidos a análise estatística 3-way ANOVA, medidas repetidas, Bonferroni (p<0,05). Para o amálgama, foram comparados rugosidade superficial e microdureza (2-way ANOVA, medidas repetidas, Bonferroni, p<0,05). Verificou-se que condições de inumação e de afogamento produzem alteração de cor nos materiais restauradores estéticos, que não é tempo dependente. Não houve diferença (p>0,05) na microdureza dos materiais restauradores estéticos em função dos agentes e tempos testados, apesar de apresentarem diferenças inerentes quanto a essa propriedade. Houve alteração significativa (p<0,05) na microdureza do AM, após 6 meses de afogamento. Quanto à rugosidade de superfície, não houve diferença significante (p>0,05) para nenhum dos materiais, agentes e tempos testados. Concluiu-se que a contribuição desses métodos à identificação humana após inumação ou afogamento só é possível considerando-se a microdureza, sendo auxiliada pela análise da alteração de cor do material. Não é possível predizer o tempo de inumação ou afogamento de um indivíduo apenas com base nos parâmetros estudados / The purpose of this study was to evaluate the effect of simulated drowning and burial conditions on color stability, surface roughness and microhardness of composite resin (RC), glass ionomer cement (CIV) and silver amalgam (AM), aiming to provide elements for differentiation of aesthetic materials and estimation of the time of the agents have been subjected to these conditions. 60 bovine incisors were prepared with a 6 x 6 x 2mm cavity and were restored with RC FiltekMR XT Z250 (3M ESPE®), CIV KetacTM Fil (3M ESPE®) and AM capsules gs-80 (SDI®). The color, surface roughness and microhardness baselines were measured using a reflectance spectrophotometer with CIE L*a*b* system (VITA® Easyshade), a surface roughness device (Mitutoyo® Surftest SJ-201P) and a micro hardness tester (Shimadzu® HMV-2). Then, the samples were separated into two groups of 30 (n=10), in accordance with the conditions that they were subjected: simulation of burial and drowning conditions, for 1, 3 and 6 months, after which further measurements were performed. Values of &Delta;E, &Delta;L, &Delta;a e &Delta;b and the other properties of the aesthetic materials were statistically analyzed using 3-way ANOVA, repeated measures, Bonferroni (p<.05). For the amalgam, only surface roughness and microhardness were compared (2-way ANOVA, repeated measures, Bonferroni, p<.05). It was found that burial and drowning conditions produce color change in the aesthetic restorative materials, which is not time dependent. There was no difference (p>.05) in microhardness of aesthetic restorative materials caused by the agents and times tested, notwithstanding they have inherent differences regarding this property. There was significant change (p<.05) in AM microhardness after 6 months of drowning. Regarding surface roughness, there was no significant difference (p>.05) for any material, agents and times tested. It was concluded that the contribution of these methods to human identification after burial or drowning is only possible considering the hardness, being aided by the analysis of the color change of the material. It is not possible to predict the time of burial or drowning of an individual based solely on the studied parameters

Cette thèse s'intéresse au développement neuronal in vitro dans le but ultime d'enregistrer l'activité de réseaux de neurones à géométrie et connectivité contrôlées. Le développement neuronal est régi par un ensemble de régulations, intrinsèques mais également sous contrôle de facteurs extérieurs, qui permettent à la cellule d'adhérer à un substrat, de croître, et de se polariser. Une partie de ce travail de thèse explore deux types de contraintes physiques de l'environnement que sont la géométrie d'adhésion et la rugosité de surface. La première révèle l'implication des forces dans les stades précoces de développement neuronal régis par un phénomène de compétition neuritique, et permet in fine de contrôler la direction d'émission de l'axone, notamment par une inhibition de sa différenciation sur lignes ondulées. La seconde montre que la distribution des points d'adhésion peut accélérer la croissance jusqu'à favoriser la polarisation axonale. L'autre partie de ce travail s'attache à résoudre le problème technologique majeur qu'est le remplissage des sites d'adhésion par le biais d'une attraction magnétique, et démontre la possibilité de faire croître des réseaux neuronaux modèles sur nanotransistors. / This thesis focuses on in vitro neuronal development, with the long-term goal of building controlled neuron networks that would allow the recording of their electric activity. A collection of intrinsic regulations are involved in neuronal adhesion, growth and polarization, in such a way that the cell can adapt to changes in its environment. Nevertheless, this environment can affect the behavior of the cell through mechanisms that rely on biophysical signals or even physical properties of this environment. The work presented in this thesis is based on the modification of two main aspects of the physical environment: geometry of adhesion and surface roughness. On the one hand, the geometry is controlled by patterns of adhesions, giving the ability to design bipolar motifs that highligt the importance of mechanical forces in neuronal growth, and also more complex motifs that allow the control of neuronal polarization, in particular by an inhibition of axonal differenciation on curved lines. On the other hand, a roughness below the microscale creates a distribution of adhesion points that results in an increase in neuronal growth rate and even influences axonal polarization. The final part of this thesis focuses on the development of an innovative method for placing cells at precise locations on a substrate, by the help of magnetic traps. This method is the final step required for growing model neuron networks on our nanotransistors.

Dans le contexte actuel du réchauffement climatique, l'une des principales sources d'incertitude pour l'élévation du niveau de la mer est la contribution de la calotte Antarctique. L'étendue et les conditions météorologiques extrêmes de ce continent font de la télédétection spatiale un moyen utile pour son suivi sur le long terme. Les observations satellites altimétriques et radiométriques dans la gamme des micro-ondes rendent compte de l'évolution des propriétés du manteau neigeux de la calotte. L'altimétrie radar, par des mesures répétées de l'élévation de la topographie de surface, permet de quantifier les variations de volume sur l'ensemble du continent. Cependant, la pénétration de l'onde radar dans la neige affecte négativement cette quantification. Les méthodes proposées pour minimiser les erreurs de pénétration sont toutes basées sur des relations avec le coefficient de rétrodiffusion radar. La compréhension des variations annuelles et inter-annuelles du coefficient de rétrodiffusion est nécessaire pour améliorer la précision de l'estimation de l'élévation de la surface donc du bilan de volume de la calotte. Cette thèse a pour objectif d'étudier le coefficient de rétrodiffusion mesuré par les altimètres sur l'ensemble du continent, sujet qui jusqu'à aujourd'hui a reçu peu d'attention. Les altimètres radars embarqués à bord d'ENVISAT (bandes S et Ku) et de SARAL/AltiKa (bande Ka) ont des sensibilités différentes aux propriétés de la neige. Nous nous sommes intéressés aux caractéristiques annuelles et inter-annuelles des coefficients de rétrodiffusion dans ces trois bandes. Une étude de sensibilité a été réalisée avec un modèle électromagnétique afin de déterminer les propriétés du manteau neigeux qui dominent le signal saisonnier. On montre que le signal saisonnier est sensible à la densité et la rugosité de surface dans la bande S, à la température de la neige dans la bande Ka et à l'une ou à l'autre de ces variables selon la région dans la bande Ku. Les caractéristiques saisonnières du coefficient de rétrodiffusion sont ensuite comparées à celles des températures de brillance acquises par les radiomètres à bord de SARAL et de SSM/I. Les résultats indiquent une influence significative de la rugosité de surface sur les températures de brillance de la bande Ka, influence souvent considérée négligeable dans la modélisation de la température de brillance. Cette étude apporte une meilleure connaissance de la dynamique saisonnière des propriétés de proche surface de la calotte Antarctique. Elle fournit de nouveaux indices pour développer dans le futur des algorithmes robustes de correction de l'erreur de pénétration. Elle met également en lumière l'importance des missions altimétriques multi-fréquences et les possibilités qu'offrent le signal de la bande S pour l'étude des variabilités saisonnières de la rugosité de surface. En définitive, la rugosité de surface est un paramètre important à prendre en compte pour obtenir de meilleures estimations et modélisations des coefficients de rétrodiffusion et des températures de brillance. / In the context of global climate changes, the Antarctic ice sheet contribution to sea-level rise is one of the main uncertainty sources. The extent and extreme meteorological conditions of this continent render remote sensing a useful tool for long term monitoring. Altimetry and radiometry observations in the microwave range reveal variations of the volume of the ice sheet and surface properties of the snowpack. Radar altimeters, provide repeated observations of the surface topography elevation, which allow the quantification of volume variations of the ice sheet. However, the penetration of radar waves in dry and cold snowpack adversely affects the estimated surface elevation. Approaches to minimize the penetration error are all based on a relationship with the backscattering coefficient. Understanding the annual and interannual variations of the backscattering coefficient is thus a key issue in order to improve the estimation accuracy of the surface elevation and to refine the ice-sheet volume trend. This thesis aims at studying the backscattering coefficients acquired by radar altimeters, which until now have received little attention. Radar altimeters on board ENVISAT (S and Ku bands) and SARAL/AltiKa (Ka band) have different sensitivities to the snowpack properties. The annual and interannual variations of the backscattering coefficient at the three bands is investigated. Sensitivity tests are carried out with an electromagnetic model to determine the prevailing snowpack properties that drive the signal. The seasonal signal is sensitive to surface density and roughness at S band, to snow temperature at Ka band and to either snow surface density and roughness or temperature depending on the location on the continent at Ku band. The seasonal signal of the backscattering coefficient is then compared with that of the brightness temperature measured by radiometers on SARAL and SSM/I. The results show a significant influence of surface roughness on brightness temperatures at Ka band, which has often been neglected in brightness temperature modeling studies. This thesis provides a better understanding of the seasonal dynamics of the near surface properties of the Antarctic ice sheet. It also provides new clues to build a more robust corrections of the penetration errors in the future. It highlights the importance of multi-frequency altimetry missions and the potential of the S band to study the seasonal variability in surface roughness. In summary, surface roughness is an important property which should be taken into account for a better modeling of backscattering coefficient and brightness temperature.

Seit ihrer Erfindung in 1994 haben sich Quantenkaskadenlaser (QCL) zu der Standard-Halbleiterlaserquelle im mittleren und weiten Infrarotspektrum entwickelt. Diese unipolaren Laser basieren auf der Populations-Inversion zwischen quantisierten sub-Bändern in Halbleiterheterostrukturen. Ein gutes theoretisches Modell ist essenziell für die Optimierung und weitere Entwicklung von neuen QCL Laserquellen. Eine einfache Methode, Elektronentransport in QCL zu beschreiben, stützt sich auf ein phänomenologisches Modell für die Streuraten zwischen elektronischen sub-Bändern. Das Hauptziel dieser Arbeit ist die Entwicklung eines kompakten Ansatzes für Streuraten für die effiziente Vorhersage der temperaturabhängigen Charakteristika von QCLs im mittleren Infrarotspektrum. Die Arbeit beginnt mit einem kurzen Überblick über Halbleiterheterostrukturen und die wichtigsten Streumechanismen für Übergänge zwischen sub-Bändern in QCLs. Dabei sind elastische Übergänge sowie Phononenstreuung für die Übergangsraten zwischen verschiedenen sub-Bändern relevant. Außerdem werden die notwendigen Modellierungstechniken für Simulationsprozesse in QCLs mit einem selbst-konsistenten Streuraten-Modell vorgestellt. In dieser Arbeit wurde ein vereinfachtes Modell für vertikalen Elektronentransport zwischen sub-Bändern bei der Temperatur von Flüssigstickstoff entwickelt. Die Übergangsrate ist in diesem Ansatz das Produkt des Überlappintegrals der quadrierten Moduli der einhüllenden Funktion und einem phänomenologischen Faktor, der von der Übergangsenergie abhängt. Der Übergangsfaktor wird für verschiedene Übergangsmechanismen einzeln hergeleitet, und eine Erweiterung des Modells auf einen breiten Temperaturbereich wird vorgestellt. Schließlich analysieren wir die sogenannte T0-Charakteristik für einige Designs der aktiven Region, die aus Rechnungen mit vorhandenen temperaturabhängigen Modellen und experimentellen Daten gewonnen wurden. / Since their invention in 1994, quantum cascade lasers (QCLs) have become the standard semiconductor laser source for the mid- and far-infrared spectral range. These unipolar devices are based on the population inversion between quantized subbands in biased semiconductor heterostructures. A useful theoretical model is essential for the optimization and further development of new QCL sources. A simple method for describing the electron transport in QCL is based on scattering rates between electron subbands. These can be described easiest using a phenomenological model with experimental or empirical parameters. The main goal of this work is development of compact description of scattering processes in the frame of scattering-rate approach for the reliable prediction of temperature dependent characteristics of mid-infrared quantum cascade lasers. We start this work with a brief overview of semiconductor heterostructures and main intersubband scattering mechanisms for quantum cascade lasers. The resulting transition rates from initial states to another subbands are described by phonons and elastic scattering. Additionally, necessary modeling techniques are considered for simulation processes in QCLs using self-consistent scattering-rate model. Based on original work we introduce a simplified model for vertical electron transport between separated subbands at liquid nitrogen temperatures. In this approach the transition rate is written as the product of the overlap integral for the squared moduli of the envelope functions and a phenomenological factor that depends on the transition energy. The approach is reviewed and extended for a broad temperature range. There, the transition factor is derived and written for different scattering mechanisms separately. Then we analyze “so-called” T0 characteristic for a number of active region designs received from the calculations by present temperature dependent model and the experimental data.

Orientador: César Gustavo da Rocha Lima / Resumo: O Brasil, frente aos acidentes ocorridos em Mariana – MG (2015) e em Brumadinho – MG (2019), tem vivenciado inúmeras discussões no que tange à assuntos regulatórios e à confiabilidade das barragens construídas no país. Neste trabalho, inicialmente, fez-se um breve comparativo entre a legislação brasileira e alguns normativos internacionais (China, Portugal, Estados Unidos e África do Sul) sobre segurança de barragens, observando-se a existência de diferentes aspectos abordados entre eles. A Política Nacional de Segurança de Barragens se demonstrou uma das regulamentações menos rígidas entre as analisadas quanto a pré-requisitos técnicos para sua aplicação, deixando grande parte das barragens de pequeno porte dispensadas do cumprimento de algumas obrigações. Além disto, a legislação federal brasileira foi implementada há menos de uma década, o que implica, atualmente, em uma dificuldade muito grande do empreendedor, dos órgãos fiscalizadores e do governo federal a se adaptarem a possuir esta cultura de segurança de barragens. Diante da interface destas construções com o meio ambiente, faz-se necessário um monitoramento constante das estruturas por uma equipe multidisciplinar e um programa de segurança consistente que vise garantir a integridade do meio ambiente nas áreas de influência das barragens, bem como resguardar o bem-estar e a vida da população situada a jusante. O uso de funções matemáticas e softwares para o mapeamento das áreas sujeitas aos riscos impostos pelas bar... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brazil, faced with the accidents that occurred in Mariana - MG (2015) and in Brumadinho - MG (2019), has experienced numerous discussions regarding regulatory issues and the reliability of the dams built in the country. In this work, it was made a brief comparison between Brazilian legislation and some international regulations (China, Portugal, United States and South Africa) on dam safety, observing the existence of different aspects addressed among them. The National Dams Safety Policy demonstrated one of the less rigid regulations among those analyzed regarding technical prerequisites for their application, leaving most of the small dams exempted from compliance with certain obligations. In addition, Brazilian federal legislation was implemented less than a decade ago, which currently implies a great difficulty for the entrepreneur, the inspection agencies and the federal government to adapt to having this dam safety culture. In view of the interface of these constructions with the environment, it is necessary a constant monitoring of the structures by a multidisciplinary team and a consistent safety program that aims to guarantee the integrity of the environment in the areas of influence of the dams, as well as to protect the well-being and the life of the downstream population. The use of mathematical functions and softwares for the mapping of the areas subject to the risks imposed by the dams is a great advance in the safety aspect of these structures. In this context,... (Complete abstract click electronic access below) / Mestre

La télédétection spatiale est d’une importance primordiale pour la cartographie et la surveillance des problèmes environnementaux. Son intérêt réside dans la capacité des capteurs satellitaires spatiaux à fournir des informations globales et permanentes de la planète, aux échelles locale à globale. La télédétection radar a montré son grand potentiel ces dernières années dans la caractérisation des états de surface du sol. L’état de la surface du sol, et en particulier l’humidité et la rugosité, exerce une influence fondamentale sur la répartition de la pluie entre infiltration, rétention superficielle et ruissellement. Il a un rôle essentiel dans les processus hydrologiques de surface et ceux associés à l’érosion et aux processus d’évapotranspiration. La caractérisation et la prise en compte de ces conditions de surface constituent actuellement un enjeu important pour la modélisation à base physique des processus hydrologiques ou pour le couplage surface-atmosphère. Dans ce cadre et depuis plusieurs années, plusieurs études scientifiques ont montré le potentiel des données micro-ondes actives dans l’estimation de l’état hydrique du sol et de sa rugosité de surface.Les nouveaux systèmes radar (SAR ʺSynthetic Aperture Radarʺ) ont permis d’ouvrir de nouvelles perspectives pour l’observation de la terre grâce à l’amélioration de la résolution spatiale (métrique sur TerraSAR-X et COSMO-SkyMed) et temporelle (TerraSAR-X, COSMO-SkyMed, Sentinel-1). La disponibilité depuis peu des nouveaux capteurs radar bande C Sentinel-1 (Sentinel-1A et Sentinel-1B) rend indispensable l’évaluation des données Sentinel-1 pour la caractérisation des états de surface du sol et en particulier la rugosité de surface.Le travail de thèse se structure en trois parties. La première partie consiste à évaluer les modèles de rétrodiffusion de radar les plus utilisés (IEM, Oh, Dubois and AIEM) en utilisant un large ensemble de données de SAR et des mesures expérimentales des paramètres du sol. Cette évaluation permet de trouver le modèle de rétrodiffusion le plus robuste qui simule le mieux le signal radar afin de l'utiliser par la suite dans la procédure d'inversion du signal radar pour estimer la rugosité du sol. Le deuxième axe de recherche de cette thèse consiste à proposer un modèle de rétrodiffusion radar semi-empirique pour les polarisations HH, HV et VV. Ce nouveau modèle sera construit à l'aide d'une grande base de données réelle. Ce nouveau modèle sera également utilisé dans la procédure d'inversion du signal radar pour estimer la rugosité du sol. Le dernier axe de cette thèse consiste à construire une méthode d’inversion du signal radar en utilisant les réseaux de neurones afin d’évaluer le potentiel des données Sentinel-1 pour l’estimation de la rugosité des sols en milieux agricoles. Ces réseaux de neurones seront entrainés à l'aide d'un ensemble de données synthétiques élaborées à partir des modèles de rétrodiffusion radar choisis (IEM calibré par Baghdadi et du nouveau modèle proposé) et validés en utilisant deux ensembles de données: un ensemble de données synthétiques et une base de données réelle (images Sentinel-1 et mesures in situ d’humidité et de rugosité du sol). La base de données réelle a été collectée en Tunisie (Kairouan) et en France (Versailles). / Spatial remote sensing is of paramount importance for mapping and monitoring environmental problems. Its interest lies in the ability of space satellite sensors in providing permanent information of the planet, at local, regional and global scales. Also, it provides spatial and repetitive territories visions and ecosystem views. Radar remote sensing has shown great potential in recent years for the characterization of soil surface conditions. The state of the soil surface, in particular moisture and roughness, has a fundamental influence on the distribution of rainfall between infiltration, surface retention and runoff. In addition, it plays an essential role in surface hydrological processes and those associated with erosion and evapotranspiration processes. Characterization and consideration of these surface conditions have been recently considered as an important issue for physically based modeling of hydrological processes or for surface-atmosphere coupling. In this context and for several years, several scientific studies have shown the potential of active microwave data for estimation of the soil moisture and the surface roughness.New SAR (Synthetic Aperture Radar) systems have opened new perspectives for earth observation through improved spatial resolution (metric on TerraSAR-X and COSMO-SkyMed) and temporal resolution (TerraSAR-X, COSMO-SkyMed, Sentinel-1) . The recent availability of new Sentinel-1 C-band radar sensors (free and open access) makes it essential to evaluate the potential of Sentinel-1 data for the characterization of soil surface conditions and in particular surface roughness.The work revolves around three parts. The first part consist of evaluation of the most used radar backscattering models (IEM, Oh, Dubois, and AIEM) using a wide dataset of SAR data and experimental soil measurements. This evaluation gives the ability to find the most robust backscattering model that simulates the radar signal with good agreement in order to use later in the inversion procedure of the radar signal for estimating the soil roughness. The second research axe of this thesis consists of proposing an empirical radar backscattering model for HH, HV and VV polarizations. This new model will be developed using a large real dataset. This new model also will be used in the inversion procedure of the radar signal for estimating the soil roughness. The last axe of this thesis consists of producing a method to invert the radar signal using neural networks. The objective is to evaluate the potential of Sentinel-1 data for estimating surface roughness. These neural networks will be trained using wide synthetic dataset produced from the radar backscattering models chosen (IEM calibrated by Baghdadi and the new proposed model) and validated using two datasets: one synthetic dataset and one real (Sentinel 1 images and in-situ measurements). The real datasets are collected from Tunisia (Kairouan) and France (Versailles).

La technologie de projection plasma atmosphérique (APS) est largement utilisée pour des applications industrielles. Les revêtements élaborés par APS présentent généralement certains défauts. Les travaux effectués dans cette étude ont consisté à étudier et à développer un nouveau moyen pour assurer à la fois un refroidissement efficace au cours de procédé de projection APS et une adaptation des conditions superficielles en vue d’élaborer des revêtements de haute qualité. Ce moyen consiste à la projection de glace carbonique (glace sèche ou dioxyde de carbone solide) en association avec la projection plasma. Des simulations numériques ont été réalisées, qui ont permis de constater que les dimensions de la buse de projection de glace carbonique, la pression du gaz propulsif, et les propriétés des pellets de CO2 influencent sensiblement la vitesse des pellets de CO2. A partir de ces éléments, des dimensions optimales ont été évaluées. Afin d’examiner l’effet de la projection de glace carbonique sur les revêtements réalisés par projection thermique, plusieurs types de matériaux ont été considérés, trois métalliques (acier, CoNiCrAlY et aluminium pur) et trois céramiques (Al2O3, Cr2O3 et ZrO2-Y2O3). Les microstructures des revêtements metalliques réalisés avec projection de glace sèche présentent moins d'oxydes et moins de porosité par rapport à ceux déposés par APS classique. Dans certains cas l’adhérence peut aussi être améliorée. Pour les revêtements céramiques, une réduction de la porosité ainsi qu’une amélioration significative de l’adhérence des revêtements ont été constatés. Pour le dépôt de ZrO2-Y2O3, la résistance aux chocs thermiques a été améliorée en utilisant des paramètres spécifiques. La projection de CO2 peut légèrement déformer la surface des substrats de faible dureté, et nettoyer les pollutions superficielles sur le substrat et conduire à une contrainte de compression plus élevée et à un refroidissement efficace. Il est à noter toutefois qu’un problème de condensation de la vapeur d’eau peut intervenir en cas de refroidissement du substrat trop important. / The technology of atmospheric plasma spraying (APS) is widely used for industrial applications. The coatings produced by APS generally show defects. The work was conducted to investigate and develop a new method to ensure both an effective cooling during the APS process and the adaptation of the surface condition in order to develop high quality coatings. This solution is dry ice (CO2) blasting in combination with thermal spraying. Firstly, numerical simulations were carried out, which revealed that the nozzle size of dry ice blasting, the propellant pressure and the properties of CO2 pellets, significantly affect the velocity of CO2 pellets. From these elements, the optimal dimensions were evaluated. To examine the effects of dry ice blasting on the coatings produced by thermal spraying, several types of materials were considered, three metals (steel, CoNiCrAlY and pure aluminum) and three ceramics (Al2O3, Cr2O3 and ZrO2-Y2O3). The microstructure of metal coatings produced with dry ice blasting show fewer oxides and less porosity compared to those deposited by conventional APS. In some cases the adhesion can be improved. Regarding ceramic coatings, a reduction in porosity and a significant improvement in the coating adhesion were observed. For the deposition of ZrO2-Y2O3, an improvement in thermal shock resistance was achieved using specific parameters. Dry-ice blasting may slightly impact the surface of the substrates with low hardness and could clean the surface pollutions on the substrate and lead to a higher compressive stress and an effective cooling. However, it is noted that the problem of the condensation of water vapor can occur in case of intense cooling of the substrate.

Successful wind power projects start with a realistic representation of the surface, more specifically the surface roughness of the site. This thesis investigates the use of airborne laser scans to model the surface roughness around a new wind farm. Estimations are made to find out how forest management and tree growth affects roughness length and displacement height. Data from scans two years apart for a specific site is provided by the Swedish governmental land registration authority. Next, tree height and plant area index methods are applied and analyzed using MATLAB. The results shows a difference of roughness length between 10.34% and 36.21% during an eight year period. WindPRO/WAsP is used to import roughness lengths for four specific cases. Height contour lines and meteorological data is taken from a long term corrected MESO data set. The results indicate a reduction in uncertainty in annual energy production between 0.79% and 2.89% across four different cases. This effect becomes significantly larger (12.76%) when comparing with classical land cover maps. Further on, effects of turbulence intensity are simulated.Finally, the results of a survey, sent to three large forest land owners in Sweden, show there is an interest in adapting forest management plans in favor of wind energy production if benefits can be shared.