Designing with Limit Equilibrium Methods involve a factor of safety (FS) in order to maintain the stability and to keep the resisting structure away from limit state on the safe side. Finite Element Program (such as Plaxis) on the other hand, instead of an FS, reduces the shear strength of the soil by introducing a reduction factor that is applied to tan

La marche humaine nécessite la génération de force propulsive ainsi que des forces antigravitaires pour maintenir l’équilibre. Pour cela, le système nerveux central est requis d’orchestrer la contraction des muscles des membres inférieurs, notamment les fléchisseurs plantaire de la cheville qui interface entre le sol et le corps humain. Durant la première phase de simple appui, le triceps sural (TS) est en contraction excentrique et son activation aide à soutenir le corps en résistant à la rotation du tibia sur le Tarsus. Par contre, la phase finale de simple appui est marquée par une augmentation des forces de réactions au sol « Push-off », du couple articulaire de la cheville et de l’activité électromyographique du TS. Le rôle du TS durant la phase finale de simple appui est l’objet de débat dans la littérature, où certains lui attribut le rôle de propulseurs et d’autre de soutien du corps. Dans ce travail, nous postulons que l’augmentation de l’activité du TS en phase finale de simple d’appui sert uniquement à décélérer la chute du centre de masse. En outre, nous postulons que la modulation temporelle de l’activité du TS permet de contrôler la cinématique (cadence et longueur de pas) et la cinétique de la marche. Deux études ont été mises en places pour tester les hypothèses de travail. Des données biomécaniques mesurées à partir d’une plateforme de force et l’activité EMG du soléaire et des gastrocnémiens latéral et médial de la jambe d’appui ont été collecté pour les deux études. Dans la première études des volontaires ont initié la marche sans et avec un ajout de poids de 20 kg attaché au niveau de la ceinture abdominale. L’ajout du poids augmente les forces de propulsion. Une augmentation de l’activité EMG du triceps permettrait de comprendre si le triceps participe à la génération de force propulsive. La deuxième étude est composée de deux expérimentations. Dans la première expérimentations des volontaires ont accompli 3 conditions de initiation de marche à vitesse variée tout en maintenant la longueur de pas constante. Dans la deuxième expérimentation, les sujets ont été incliné et instruit de récupérer leur équilibre en exécutant un pas de longueur différente. Les résultats ont montré que : 1) le triceps ne participe pas au push-off mais freine la chute du centre de masse en phase finale de simple appui. 2) L'amplification d’activité électromyographique durant la marche rapide est due à l’augmentation de demande de support de corps causé par la croissance des forces inertiels du corps. 3) La durée de contraction du TS permet de déterminer la cadence et la longueur de pas, donc la cinématique de la marche. La durée d’activité du TS permet aussi de déterminer la position du centre de masse par rapport au centre de pression au moment du contact avec le sol. 4) Ceci permet au TS de moduler le couple de déséquilibre responsable des forces propulsives, donc la cinétique de la marche. / Human gait necessitates the generation of both propulsive force to propel the body forward and anti-gravitational force to maintain dynamic postural equilibrium. This requires the central nervous system to orchestrate lower limb muscles. Notably the CNS has to control ankle plantar flexors activity as the whole body rotates around the ankle, which in turn interfaces with the external environment. From early to middle stance, triceps surae (TS) contracts eccentrically thus resisting tibial rotation around the tarsus. However, late stance is marked by an increase in ground reaction forces, commonly known as « Push-off », in ankle torque and electromyographic activity of TS. The role of triceps surae during late stance is object of debate in the literature. Some believe it is responsible for the push-off other insist it is sole role is to maintain dynamic postural equilibrium. In this work, we postulate that the increase in TS activity in late stance is to decelerate vertically the fall of the centre of mass. We further hypothesise that temporal modulation of TS activity determines global gait kinematics (cadence and step length) and kinetics. Two studies have been conducted to test the work hypotheses. Ground reaction force data gathered from a large force platform and EMG activity of soleus, medial and lateral gastrocnemius of stance was measured using surface electrodes. In the first study, subjects initiated gait with and without an added mass of 20 kg attached around the waist. Adding the weight increases propulsive force. If TS activity increases as well than it is responsible for generating propulsive force. The second study is composed of two experiments. In the first volunteers performed gait initiation at three different walking velocity conditions while maintain step length constant. In the second experiment, subjects were inclined and asked to recuperate their equilibrium by performing a step. They were asked to perform three step lengths. Results showed that: 1) Triceps does not participate in push-off but brakes the fall of the centre of mass during late single stance. 2) Increasing TS EMG activity in late stance is due to an increase in the requirement of maintaining dynamic postural equilibrium. 3) Control over the duration of TS activity determines cadence and step length and thus the kinematics of gait. Temporal modulation of TS also sets the position of centre of mass with respect to centre of pressure at the moment of foot-contact. 4) By controlling the distance between the two, the CNS modulates the disequilibrium torque that is responsible for propulsive force and thus the kinetics of gait.

Nos últimos anos, evidenciou-se a adoção de Programas de Transferência Condicionada de Renda (PTCR) por diversos países como parte de um esforço para reduzir seus indicadores de pobreza extrema. Sua eficácia é comprovada por muitos estudos, sendo seus resultados positivos reconhecidos em áreas como saúde, educação, redução do trabalho infantil e da desigualdade de renda, entre outros. No entanto, é escassa a literatura que aborda os resultados desses Programas para alguns desses aspectos em longo prazo. Haja vista sua relevância, destacada nos últimos anos, no combate à pobreza, o estudo aprofundado de impactos de PTCR demonstra-se fundamental para a elaboração de políticas públicas que aumentem o bem-estar da população. A presente dissertação compreende uma avaliação sobre o tema a partir da elaboração de um modelo teórico de equilíbrio geral, baseado em contribuições relevantes da literatura sobre crescimento econômico, armadilha da pobreza e igualdade de oportunidade. Esse modelo é posteriormente calibrado para diferentes cenários, verificando-se as suas principais implicações de longo prazo. A partir desse exercício, obtiveram-se resultados positivos do PTCR para indicadores como frequência escolar, renda per capita e redução da desigualdade de renda. Todavia, a eficácia do Programa depende de como ele é formatado, visto que, em alguns cenários, os impactos econômicos registrados foram nulos ou negativos / Over the last years, many countries adopted Conditional Cash Transfer Programs (CCTP) as part of an effort to reduce their extreme poverty indicators. Its effectiveness is proven by several studies, and its positive results are known in areas such as health, education, child labour reduction, income inequality reduction, among others. However, the literature concerning CCTP results for many of those aspects in the long term is scarce. Considering its relevance for fighting poverty, highlighted over the last years, making a profound study of the CCTP impacts is essential to formulate public policies that enhance population welfare. This dissertation consists of an analysis of this subject, by the elaboration of a general equilibrium theoretical model, based on relevant contributions of the literature on economic growth, poverty trap and equality of opportunity. That model is then calibrated for different scenarios, in order to verify its main long term consequences. By doing that exercise, many positive results of the CCTP were verified for variables such as school attendance, income per capita and income inequality reduction. Nonetheless, the Program\'s effectiveness depends on how it is formulated, considering that the economic results were null or negative in some scenarios.

Nos últimos anos, evidenciou-se a adoção de Programas de Transferência Condicionada de Renda (PTCR) por diversos países como parte de um esforço para reduzir seus indicadores de pobreza extrema. Sua eficácia é comprovada por muitos estudos, sendo seus resultados positivos reconhecidos em áreas como saúde, educação, redução do trabalho infantil e da desigualdade de renda, entre outros. No entanto, é escassa a literatura que aborda os resultados desses Programas para alguns desses aspectos em longo prazo. Haja vista sua relevância, destacada nos últimos anos, no combate à pobreza, o estudo aprofundado de impactos de PTCR demonstra-se fundamental para a elaboração de políticas públicas que aumentem o bem-estar da população. A presente dissertação compreende uma avaliação sobre o tema a partir da elaboração de um modelo teórico de equilíbrio geral, baseado em contribuições relevantes da literatura sobre crescimento econômico, armadilha da pobreza e igualdade de oportunidade. Esse modelo é posteriormente calibrado para diferentes cenários, verificando-se as suas principais implicações de longo prazo. A partir desse exercício, obtiveram-se resultados positivos do PTCR para indicadores como frequência escolar, renda per capita e redução da desigualdade de renda. Todavia, a eficácia do Programa depende de como ele é formatado, visto que, em alguns cenários, os impactos econômicos registrados foram nulos ou negativos / Over the last years, many countries adopted Conditional Cash Transfer Programs (CCTP) as part of an effort to reduce their extreme poverty indicators. Its effectiveness is proven by several studies, and its positive results are known in areas such as health, education, child labour reduction, income inequality reduction, among others. However, the literature concerning CCTP results for many of those aspects in the long term is scarce. Considering its relevance for fighting poverty, highlighted over the last years, making a profound study of the CCTP impacts is essential to formulate public policies that enhance population welfare. This dissertation consists of an analysis of this subject, by the elaboration of a general equilibrium theoretical model, based on relevant contributions of the literature on economic growth, poverty trap and equality of opportunity. That model is then calibrated for different scenarios, in order to verify its main long term consequences. By doing that exercise, many positive results of the CCTP were verified for variables such as school attendance, income per capita and income inequality reduction. Nonetheless, the Program\'s effectiveness depends on how it is formulated, considering that the economic results were null or negative in some scenarios.

The thesis focuses on the question of undervaluation of the renminbi exchange rate to the U.S. dollar from the perspective of three selected alternative methods of calculating long term equilibrium exchange rate. In the case of calculations of behavioral equilibrium exchange rate and the natural real exchange rate, I performed calculations by using vector error correction model. In the case of fundamental equilibrium exchange rate I used error correction model. The input data used in the models are ranging from 1980 to 2010. Those are primarily value of nominal exchange rates, price levels and foreign trade. According to my results behavioural and fundamental equilibirum exchange rate show undervaluation of the renminbi to the year 2010, while the natural real exchange rate indicates a slight overvaluation of the renminbi to the year 2010.

De nos jours, remplacer les solvants organiques utilisés traditionnellement dans l'industrie chimique par une nouvelle génération de solvants moins toxique, moins inflammable et moins polluante est un défi considérable. Les liquides ioniques, sels liquides qui satisfont ces critères, sont envisagés comme alternatives. Le but de ce travail est d'étudier le comportement des liquides ioniques en présence de composés organiques ou de gaz afin d'établir leur domaine d'applications dans le génie des procédés.Dans un premier temps, une étude chromatographique présente les interactions entre composés organiques et les liquides ioniques. Les données de rétention ont permis d'estimer la sélectivité à dilution infinie de plusieurs liquides ioniques pour différents problèmes de séparation. Un modèle de solvatation <<GC-LSER>> a été développé afin de prédire les coefficients de partage de solutés dans des liquides ioniques classiques et fonctionnalisés. Ensuite, l'étude des équilibres liquide-liquide de systèmes ternaires ont permis d'évaluer l'efficacité de trois liquides ioniques pour trois problèmes de séparation fréquemment rencontrés dans l'industrie chimique (extraction des composés aromatiques, du thiophène ou des alcools linéaires). Les valeurs des sélectivités et des coefficients de distribution élevées indiquent que les liquides ioniques étudiés peuvent remplacer les solvants traditionnels. Enfin, les performances des liquides ioniques pour la capture des gaz à effet de serre sont évaluées grâce à des mesures de solubilités du dioxyde de carbone et du protoxyde d'azote dans les liquides ioniques sous hautes pressions. Les données expérimentales ont été utilisées afin d'étendre le modèle PPR78 (Predictive 1978, Peng-Robinson equation of state) aux systèmes {CO2+ liquide ionique} / Nowadays, replacement of conventional organic solvents by a new generation of solvents less toxic, less flammable and less polluting is a major challenge for the chemical industry. Ionic liquids have been widely promoted as interesting substitutes for traditional solvents. The aim of this work is to study the behavior of ionic liquids with organic compounds or gases in order to determine their range of applications in process engineering.First, interactions between organic compounds and ionic liquids are studied using inverse gas chromatography. The activity coefficients at infinite dilution are used to calculate capacity and selectivity of different ionic liquids for different separation problems. A solvation model <<GC-LSER>> is proposed in order to estimate the gas-to-ionic liquid partition coefficients in alkyl or functionalized ionic liquids. Then, liquid-liquid equilibria measurements of ternary systems were carried out in order to evaluate the efficiency of three ionic liquids for three separation problems frequently encountered in chemical industry (extraction of aromatic compounds, thiophene or linear alcohols). The high values of distribution coefficients and selectivities indicate that the investigated ionic liquids could replace the traditional solvents. Finally, the performance of ionic liquids for greenhouse gases capture was examinated through solubility measurements of carbon dioxide and nitrous oxide in ionic liquids at high pressure. The experimental data is used in order to extend the model PPR78 (Predictive 1978, Peng-Robinson equation of state) to systems containing {CO2+ ionic liquid}

Le risque systémique menaçant le système financier est une préoccupation majeure pour les régulateurs. Les indicateurs adéquats de risque systémique devraient vraiment les aider à accomplir les lois réglementaires appropriées. La thèse propose un modèle dynamique du système bancaire pour calculer un indicateur de risque systémique de deux composantes :La probabilité d'un évènement déclencheur qui provient de la baisse des prix des actifs, et les pertes correspondantes dans le système Financier.La thèse prouve également l'existence et l'unicité de deux modèles d'équilibre de compensation : Le premier avec un modèle de différentes hiérarchies de dette et le second modèle avec plusieurs stratégies de liquidation / Systemic risk threatening the financial system is a major concern for regulators. Adequate indicators of systemic risk would help them perform appropriate regulatory laws.The thesis proposes a dynamic model of banking system to calculate a systemic risk indicator of two components : The probability of a triggering event originated from external asset price decline, and the corresponding losses through the financial system. The thesis also proves the existence and uniqueness of two clearing equilibrium: the first deals with a model of différent debt seniorities, the second with a model of several illiquid asset following a proportional liquidation strategy.