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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Impacto das transferências incondicionais nos indicadores de saúde dos municípios brasileiros

Ribeiro, Fernanda Patriota Salles 06 February 2015 (has links)
Submitted by Fernanda Patriota Salles Ribeiro (fernandapsr@gmail.com) on 2015-02-22T16:17:22Z No. of bitstreams: 1 2015_02_22_RIBEIRO.pdf: 2900653 bytes, checksum: 3225b281df8fb5f8111a58db4d850612 (MD5) / Approved for entry into archive by Renata de Souza Nascimento (renata.souza@fgv.br) on 2015-02-23T23:03:25Z (GMT) No. of bitstreams: 1 2015_02_22_RIBEIRO.pdf: 2900653 bytes, checksum: 3225b281df8fb5f8111a58db4d850612 (MD5) / Made available in DSpace on 2015-02-24T13:41:27Z (GMT). No. of bitstreams: 1 2015_02_22_RIBEIRO.pdf: 2900653 bytes, checksum: 3225b281df8fb5f8111a58db4d850612 (MD5) Previous issue date: 2015-02-06 / Este estudo visa avaliar o impacto das transferências de recursos incondicionais nos indicadores de saúde dos municípios brasileiros. A transferência abordada refere-se ao Fundo de Participação dos Municípios (FPM), tal recurso não possui uma destinação pré-definida pelo Governo Federal, porém pelo menos 15% do seu valor deve ser gasto em saúde pública. A base de dados utilizada teve como principais fontes o DATASUS e o SIOPS, a periodicidade é anual e a unidade de observação refere-se aos municípios. Para estimar o impacto do FPM na mortalidade, na morbidade e nas medidas preventivas, foram aplicadas duas metodologias econométricas: Painel com efeito fixo e Regressão Descontínua. A primeira abrangeu o período de 2002 a 2011 e os resultados encontrados mostram que o FPM possui um impacto negativo significante na mortalidade total e para os indivíduos de 15 a 29 anos, 30 a 59 anos e 60 anos ou mais. Em relação à morbidade, os modelos em Painel com efeito fixo mostraram um impacto negativo do FPM sobre as internações hospitalares. Para as medidas preventivas, as estimações apresentaram resultados não significantes ou então opostos ao esperado. O método da Regressão Descontínua foi também aplicado, pois o FPM apresenta características de descontinuidade, o que traz a possibilidade de uma aplicação econométrica cada vez mais utilizada e que possui uma estratégia de identificação que deve levar a resultados similares aos de um experimento aleatório. O período utilizado para tal estimação refere-se aos anos de 2002 a 2010. A partir desse método, verificou-se resultados bastante sutis em relação ao impacto do FPM sobre os indicadores de saúde: para mortalidade o FPM não apresentou impacto significativo e robusto, para morbidade novamente foi encontrado um impacto negativo e significante, e, por fim, para as medidas preventivas o resultado mais robusto refere-se às consultas do Programa Saúde da Família, em que o FPM apresentou impacto positivo e significante para alguns dos coeficientes gerados. / This study assesses the impact of unconditional resources transfers in health indicators of Brazilian municipalities. The approached transfer refers to the Participation Fund of Municipalities (Fundo de Participação dos Municípios – FPM), this feature does not have a pre-defined allocation by the Federal Government, but at least 15% of its value should be spent on public health. The database used had as main sources DATASUS and SIOPS, the periodicity is annual and the observation unit refers to the municipalities. To estimate the impact of the FPM in mortality, morbidity, and on preventive measures, we applied two econometric methodologies: Panel with fixed effects and Regression Discontinuity Design - RDD. The first covered the period 2002-2011 and the results show that the FPM has a significant negative impact on total mortality and for individuals 15-29 years, 30 to 59 years and 60 years or more. In terms of morbidity, the models in Panel with fixed effects showed a negative impact of FPM on hospitalizations. To preventive measures, the estimates didn’t show significant results or the coefficients are opposites of the expected. The RDD method was also used because FPM has discontinuity characteristics, which brings the possibility of an econometric application increasingly used and that has an identification strategy that should lead to results similar to those of a random experiment. The period used refers to the years 2002 to 2010. From this method, the estimated results were quite subtle: the FPM hadn't significant and robust impact for mortality, for morbidity was found again a negative and significant impact, and finally, for preventive measures the only robust result refers to the queries of the Family Health Program, in which the FPM had a positive and significant impact on some of the generated coefficients.
412

Impacto das transferências condicionadas de renda sobre a proficiência dos alunos do ensino fundamental no Brasil

Santarrosa, Rogério Bianchi 17 May 2011 (has links)
Submitted by Cristiane Shirayama (cristiane.shirayama@fgv.br) on 2011-08-20T18:45:12Z No. of bitstreams: 1 DISSERT_ROGERIO BIANCHI SANTARROSA.pdf: 360667 bytes, checksum: 058eb45becdcdf8d90fb3a3a2991cabc (MD5) / Approved for entry into archive by Gisele Isaura Hannickel (gisele.hannickel@fgv.br) on 2011-08-22T12:14:04Z (GMT) No. of bitstreams: 1 DISSERT_ROGERIO BIANCHI SANTARROSA.pdf: 360667 bytes, checksum: 058eb45becdcdf8d90fb3a3a2991cabc (MD5) / Approved for entry into archive by Gisele Isaura Hannickel (gisele.hannickel@fgv.br) on 2011-08-22T12:26:30Z (GMT) No. of bitstreams: 1 DISSERT_ROGERIO BIANCHI SANTARROSA.pdf: 360667 bytes, checksum: 058eb45becdcdf8d90fb3a3a2991cabc (MD5) / Made available in DSpace on 2011-08-22T12:39:53Z (GMT). No. of bitstreams: 1 DISSERT_ROGERIO BIANCHI SANTARROSA.pdf: 360667 bytes, checksum: 058eb45becdcdf8d90fb3a3a2991cabc (MD5) Previous issue date: 2011-05-17 / This paper attempts to estimate the impact of conditional cash transfer on students’ proficiency in Brazil. Conditional Cash Transfers literature has already showed significant evidence about the impact of those kind of social programs on school enrollment. However, we know very little about the impact of these policies on final capital human measures, such as proficiency. Furthermore, this paper relates to the literature about the impact of public policies on test scores. We find important relationships between program selection and basic characteristics of eligible group. Eligible group has generally less favorable social and economic features and lower test scores. We take advantage of a unique student’s panel to estimate causal effect. We explore fixed effect and difference-in-difference estimators and extension, such as triple difference and difference-in-difference combined with reweighting based on propensity score estimators. In general, results show that is no impact of those kind of programs on proficiency level in math and language. / Este artigo propõe estimar o impacto dos programas de transferência condicionada de renda sobre proficiência dos alunos no Brasil. A literatura de transferência condicionada de renda já mostrou bastantes evidências do impacto desse tipo de programa social sobre acesso e matrícula escolar. Porém, muito pouco se sabe sobre o efeito dessas políticas sobre medidas finais de capital humano como proficiência. Além disso, esse estudo também se insere na literatura de avaliação de impacto de políticas públicas sobre proficiência. Nós diagnosticamos em nosso trabalho importantes relações que envolvem a seleção desse tipo de programa e as características descritivas básicas e distintas do grupo de recipientes. Os recipientes do programa geralmente possuem características socioeconômicas menos favoráveis e notas de proficiência mais baixas, mesmo quando controlado por características socioeconômicas observáveis. Para estimar o efeito causal, fazemos uso de uma oportunidade única de construção de um painel de alunos. Exploramos modelos de estimadores de efeito fixo, diferença em diferença e extensões, como diferenças triplas e diferenças em diferenças combinada com reponderação baseada no propensity score. Os resultados, em geral, apontam que não há impacto desse tipo programa em notas de proficiência de matemática e português.
413

Maintaining systems-of-systems fit-for-purpose : a technique exploiting material, energy and information source, sink and bearer analysis

Hinsley, Steven W. January 2017 (has links)
Across many domains, systems suppliers are challenged by the complexity of their systems and the speed at which their systems must be changed in order to meet the needs of customers or the societies which the systems support. Stakeholder needs are ever more complex: appearing, disappearing, changing and interacting faster than solutions able to address them can be instantiated. Similarly, the systems themselves continually change as a result of both external and internal influences, such as damage, changing environment, upgrades, reconfiguration, replacement, etc. In the event of situations unforeseen at design time, personnel (for example maintainers or operators) close to the point of employment may have to modify systems in response to the evolving situation, and to do this in a timely manner so that the system and/or System-of-Systems (SoS: a set of systems that have to interoperate) can achieve their aims. This research was motivated by the problem of designing-in re-configurability to the constituent systems of a SoS to enable the SoS and its systems to effectively and efficiently counter the effects of unforeseen events that adversely affect fitness-for purpose whilst operational. This research shows that a SoS does not achieve or maintain fitness-for-purpose because it cannot implement the correct, timely and complete transfer of Material, Energy and Information (MEI) between its constituents and with its external environment that is necessary to achieve a desired outcome; i.e. the purpose.
414

Modélisation et étude de la macroségrégation au cours de la refusion à l'arc sous vide : application aux alliages de zirconium / Modeling and Study of the Macrosegregation during Vacuum Arc Remelting : Application to Zirconium Alloys

Revil-Baudard, Mathieu 09 July 2012 (has links)
Le procédé VAR (Vacuum Arc Remelting ou refusion à l'arc sous vide en français) est employé dans la production d'alliages à haute performance pour les industries aéronautique (aciers spéciaux, superalliages et alliages de titane) et nucléaire (alliage de zirconium). Comme pour tous les procédés de fonderie, la maîtrise de l'homogénéité chimique et de la structure métallurgique des lingots coulés par le procédé VAR constitue un enjeu industriel important. Les travaux présentés dans ce mémoire visent à identifier, pour les alliages de zirconium en particulier, les effets de la convection naturelle et de la convection forcée due au brassage électromagnétique sur la macroségrégation. Dans ce but, un modèle numérique a été développé. Il est basé sur la résolution couplée des équations de conservation d'énergie, de quantité de mouvement et de solutés, dans des conditions d'écoulement laminaire ou turbulent. La modélisation de la solidification tient compte du couplage fort entre le transport d'énergie et de solutés dans la zone pâteuse. Afin de décrire la microségrégation, la diffusion restreinte des solutés dans les phases liquides et solides peut être prise en compte. Parallèlement, deux électrodes chimiquement homogènes d'alliages Zircaloy-4 et M5® ont été spécialement refondues dans un four VAR industriel sur le site de CEZUS à Ugine (Savoie, France). La macroségrégation des lingots obtenus a été caractérisée.La comparaison entre les mesures expérimentales et les résultats de simulation a montré que pour un alliage dont l'intervalle de solidification est important (comme l'alliage Zircaloy-4), la convection solutale dans la zone pâteuse peut avoir une influence essentielle sur la macroségrégation de la région centrale du lingot. Par ailleurs, le mouvement de grains équiaxes lors de l'application d'un brassage électromagnétique de forte intensité semble accentuer significativement la macroségrégation dans la région externe du lingot. Pour un alliage dont l'intervalle de solidification est faible (comme l'alliage M5®), nous avons montré que la macroségrégation dépend plus spécifiquement de la convection forcée due au mode de brassage électromagnétique appliqué au cours de la refusion / Vacuum Arc Remelting (VAR) is used to produce high performance alloys for the aeronautic (special steels, superalloys, titanium alloys) and nuclear (zirconium alloys) industries. As for all casting processes, the control of the chemical homogeneity and the metallurgical structure in VAR ingots is an important industrial issue. The goal of this thesis is to identify, for zirconium alloys in particular, the effects of the natural convection and the forced convection due to the electromagnetic stirring on macrosegregation. To this purpose, a numerical model has been developed. It is based on the solution of the coupled transient energy, momentum and solute transport equations, under laminar or turbulent flow conditions. The solidification modeling accounts for a full coupling between energy and solute transport in the mushy zone. The finite diffusion of solutes in both solid and liquid phases can be taken into account to describe microsegregation. In addition, chemically homogeneous Zircaloy-4 and M5® electrodes have been specially remelted in an industrial VAR furnace at the CEZUS plant in Ugine (Savoie, France). The macrosegregation of the ingots has been measured. The comparison between the experimental measurements and the simulation results showed that for an alloy with a large solidification interval (like Zircaloy-4), the solutal convection in the mushy zone could have an essential influence on the macrosegregation in the inner part of the ingot. Furthermore, the motion of equiaxed grains caused by a strong stirring seems to seriously intensify macrosegregation in the outer part of the ingot. For an alloy with a small solidification interval (like M5®), we have shown that the macrosegregation depends more specifically on the forced convection due to the type of stirring applied during the remelting
415

Choix et trajectoires techniques dans le domaine ibérique à la fin de l'Âge du Fer : la cuisson des matériaux céramiques dans la vallée de l'Èbre (IIIe-Ier s. av. J.-C.) / Technological choices in Iron Age Iberia : ceramic firing in the Ebro valley (3rd-1st c. BC)

Frerebeau, Nicolas 25 April 2015 (has links)
L’objet de la présente étude relève d’une approche technologique du domaine ibérique à la fin de l’Âge du Fer. L’orientation donnée à notre étude est celle d’un intérêt porté à l’origine d’une innovation : les pratiques de cuisson de la céramique ibérique. Il s’agit d’identifier les modalités selon lesquelles s’articulent matières disponibles, techniques et matériaux fabriqués et de mettre en évidence les jeux d’actions et de rétroactions qui existent entre ces trois composantes au sein de la vallée de l’Èbre. L’étude du matériel issu d’un centre de production – l’atelier de potiers du Mas de Moreno (Foz-Calanda, Teruel, Espagne ; iiie-ier s. av. J.-C.) – revêt dans ce cadre un intérêt particulier : en s’attachant à ce qui relève du raté, il devient possible d’isoler les causes du refus et, par contraste, de mettre en évidence les choix caractérisant une situation normale de production. L’analyse des matériaux fabriqués au sein de l’atelier permet alors d’illustrer la complexité des mécanismes en jeu. En s’attachant à l’articulation entre la gestion des aspects thermiques liés à la cuisson et la mise en œuvre d’une matière argileuse aux qualités particulières, il est possible de proposer une restitution des modalités de gestion du risque au cours de la production. L’acceptation d’une part de risque apparaît alors comme un des moteurs de l’innovation, autorisant une évolution progressive des pratiques de cuisson et l’adoption de techniques nouvelles. / This work aims to understand the technological history of Iron Age Iberia, particularly by focusing on Iberian ceramic firing practices. By highlighting feedbacks and interconnections, main objectives of this thesis are the investigation of the links between the pathways of row material, knowhow and products evolution in the Ebro valley. Details investigations were conducted on the potter workshop of the Mas de Moreno (Foz-Calanda, Teruel, Spain; 3rd-1st c. BC). Here the examination of the variety of defects and failures during the production process allowed a specification of the ideal process. The overall complexity of the production process was evaluated by chemical and mineralogical material analysis. Thermal details of ceramic firing and peculiar properties of the used clayey material enabled us, for the first time, to propose a hypothesis on the production risk management. It appears that the acceptance of risk was the driving force for innovation, allowing for a gradual and steady evolution of the firing practices and the adoption of new techniques.
416

An empirical study of e-banking in Cameroon

Talla, Jacques Herve Nguetsop 06 1900 (has links)
The objective of this study was to determine the factors which can affect the adoption of e-banking in Cameroon. To conduct that research, we tried to understand how demographic characteristics, attitudes and social influences impact on the customer’s decision to adopt e-banking; to investigate barriers and challenges with regard to the adoption of e-banking; to identify the differences in perception regarding e-banking between e-banking users and non-users; and to determine whether or not e-banking offers more opportunities in comparison with the traditional banking system used in Cameroon. Through an in-depth interview and questionnaires filled by bank’s customer, the factors influencing the adoption of e-banking in Cameroon were identified. These were demographic factors such as age, income, educational level and occupation. Psychological factors such as perceptions of relative advantage, compatibility, complexity and perceived cost were also identified. Perceived risk was found to have a negative impact on e-banking adoption. A measure of the relationship between the factors and the adoption of e-banking was determined. Negative perceptions and attitudes influence the decision-making process, resulting in negative consumer behaviour outcomes. Social influences, including the opinions of friends, parents and colleagues, were found to have an influence on e-banking adoption. With regard to the research objectives that identified factors discouraging customers from using e-banking, the lack of trust, lack of information, lack of knowledge and perceived risk by non-users hindered the adoption of e-banking. Challenges and barriers with regard to e-banking adoption were also identified, namely resistance to change by bank employees, lack of knowledge, absence of e-laws and legislation for e-banking, absence of a proper telecommunications infrastructure and shortage of IT training. This research is especially valuable for the Cameroon banking industry, as the findings will provide insights for banks interested in implementing e-banking strategies. / Business Management / M. Com. (Business Management)
417

Les bétons bas pH : comportements initial et différé sous contraintes externes / Low pH concretes : instantaneous and delayed behaviors under external stress

Leung Pah Hang, Thierry 22 May 2015 (has links)
Dans le cadre du stockage des déchets radioactifs en couches géologiques profondes (argilite du Callovo-Oxfordien), des bétons à faible alcalinité et à faible chaleur d'hydratation référencés "bas pH " ont été élaborés. L'utilisation de ces types de béton permet de limiter la dégradation des propriétés confinantes du matériau argileux type bentonite. Deux bétons bas pH à base de liants ternaires ont étudiés : un composé de ciment, fumée de silice et cendres volantes (TCV) et l'autre composé de ciment, fumée de silice et laitier moulu de haut fourneau (TL). L'objectif de l'étude est d'analyser le comportement de ces matériaux pour s'assurer : d'une mise en œuvre correcte à l'échelle industrielle, d'une bonne tenue chimique et mécanique dans le temps et d'un confinement performant. Le programme expérimental comprend la caractérisation physico-chimique et mécanique de ces matériaux à forte teneur en additions et est couplé à de la modélisation dans le but, in fine, de disposer d'outils permettant de prédire leur comportement au sein de l'ouvrage. Les résultats montrent qu'un cobroyage des constituants du liant permet d'améliorer la réactivité du liant et de s'assurer d'une bonne robustesse des formules de béton. La condition essentielle de l'obtention d'un pH de leur solution interstitielle de 11 est assurée dès 28 jours. Les bétons peuvent être considérés à faible chaleur d'hydratation du fait des échauffements rencontrés à court terme. A long terme, de hautes performances mécaniques, de faibles coefficients de perméabilité et de diffusion sont obtenus sur ces matériaux. Les modélisations de l'hydratation, de l'évolution de propriétés mécaniques, de l'endommagement, des déformations différées et des transferts hydriques ont été abordées. Le modèle d'hydratation utilisé a été adapté aux liants ternaires en prenant en compte les phénomènes de nucléation des additions sur l'hydratation du ciment. Pour les autres modèles, l'acquisition des mesures expérimentales a permis de fournir les données d'entrée pour leur utilisation et de vérifier leur validité sur des liants fortement dilués. Tous ces travaux permettent au final d'envisager sereinement la modélisation et la prédiction du comportement des structures réalisées en béton bas pH. / In the context of the radioactive wastes disposal in deep geological repository of clay, low-alkalinity and low heat of hydration concretes referenced "low pH " were designed. The degradation of the properties of the clay can be limited by using these types of concrete. Two types of low pH binder were chosen for this research: the first one is comprised of cement, silica fume and fly ash (TCV) and the other one is comprised of cement, silica fume and slag (TL). The objective of this research is to comprehend the behavior of these concrete in order to ensure the well-placing of the fresh concrete at an industrial scale and good mechanical performances, chemical stability and confining properties. The experimental program focuses on a physico-chemical and mechanical characterization of these recent materials with high pozzolanic addition content. The experimental data are then modeled for the purpose of having a tool that, in the end, is able to predict the behavior of the low pH concretes within the structure. The results show that grinding altogether the three constituents improves the reactivity of the binder and allows a good reproducibility of the low pH design. The most important criterion which is a pH of the interstitial solution below 11 is met at 28 days. The heat measurements at early age show that the low pH concretes are low heat of hydration concretes as well. In the long run, high mechanical performances, low permeabilities and diffusivities were obtained on these materials. The modeling of the hydration, evolution of mechanical properties, damage, creep and hydric transfers is also covered in this thesis. The model of hydration was adjusted to match the hydration of ternary binders by taking into account the effects of the additions such as the heterogeneous nucleation, on the hydration of the cement. As for the other models, the experimental results were used as data input to validate the models on binders with high replacement rates. Ultimately, this work allows us to contemplate serenely the modeling and the prediction of the behavior of structure made of low pH concretes.
418

Caractérisation hydro-thermique d’un réacteur industriel : vers un nouveau procédé plus performant / Hydro-thermal characterization of an industrial reactor : towards a more efficient process

Zenner, Alexis 29 May 2018 (has links)
L'hydrodynamique et les transferts thermiques dans des réacteurs types lits fixes font l'objet d'études depuis une soixantaine d'années. Les informations fournies par ces travaux sont importantes pour le dimensionnement des réacteurs industriels. En effet, une étroite relation entre les propriétés de transports et le design du procédé (réacteur et support catalytique) est mise en avant dans l'état de l'art. Mais force est de constater que la complexité des phénomènes entraine des divergences entre les observations et les différentes conclusions faites par les auteurs. Deux pilotes à échelle laboratoire ont été conçus et mis en place au cours de cette thèse. L'un est dédié à l'étude hydrodynamique et l'autre à l'étude thermique. La caractérisation hydro-thermique des réacteurs passe également par une étape de développement de modèles mathématiques associés aux pilotes. Ils représentent les transferts opérant au sein d'une colonne garnie. Ils permettent également d'estimer les paramètres effectifs du milieu poreux. Les quatre grandeurs caractéristiques étudiées dans cette thèse sont les pertes de charges, la dispersion axiale, la conductivité effective globale et le coefficient d'échange thermique à la paroi. Les résultats obtenus à partir des modèles sont comparés aux travaux de la littérature. Ceci permet de valider les méthodes d'estimation développées dans cette thèse. Il est remarqué que les corrélations prédictives de la conductivité effective sont peu adaptées aux morphologies de supports les plus complexes. Nous proposons donc aussi de nouvelles corrélations basées sur nos mesures / Hydrodynamics and heat transfers in packed bed reactors have been studied for about sixty years. The information supplied by this work is important for the design of industrial reactors. Indeed, there is a close relationship between the heat and mass transfers and the design of the process (reactor and catalytic support); this is highlighted in the state of the art. It is clear that the complexity of the phenomena is the cause of divergences between the observations and the conclusions made by the authors. Two laboratory-scale pilots were designed and set up during this PhD thesis. One is dedicated to the hydrodynamic studies and the other to the thermal studies. The hydro-thermal characterization of the reactors includes a step of development of mathematical models associated with the pilots. They represent transfers occurring within the bed of particles. Coupling experimental data with the models allows estimating the effective parameters of the porous medium. The four characteristic quantities studied in this PhD thesis are the pressure drop, the axial dispersion, the overall effective conductivity and the heat transfer coefficient at the wall. The results are compared with the data provided by the open literature. This validates the estimation methods developed during this PhD thesis. It is noticed that the predictive correlations of the effective thermal conductivity are not adapted to the morphologies of the most complex supports. Based on our measurements, new correlations were developed
419

O novo sistema de pagamentos brasileiro : houve redução de custos e riscos?

Lampert, Carlos Henrique Borges January 2006 (has links)
Esta dissertação analisa os motivos da implantação do novo sistema de pagamentos brasileiro, descreve os impactos percebidos junto à sociedade e avalia o atual estágio do projeto. Procura mostrar que não houve redução de risco sistêmico, como se pretendia, em função da implantação do novo sistema de pagamentos. Também evidencia que não houve redução de tarifas bancárias com a implantação do mesmo. Descreve que, em função da redução de custos financeiros percebidos com a utilização de avanços tecnológicos, os bancos passaram a apropriar-se dos ganhos em função da forma como foi elaborado o novo sistema, não foi possível identificar qualquer redução de preço nas tarifas bancárias em função de uma maior concorrência. / This dissertation analyzes the motives of the implementation of the new system of Brazilian payments, describes the impacts perceived into the society and evaluates the current stage of the project. The study showed that there was neither reduction of systemic risk nor banking fees after the implementation of the new system of payments. It describes that banks kept the earnings acquired from of the reduction of financial costs perceived with the utilization of technological advancements. The way the new system was setup prevented an identification of any reduction of banking tariffs because of increased market competition.
420

Contribution à l'étude des transferts de fluides dans les installations de stockage des déchets non dangereux / Contribution to the study of fluid transfers in Municipal Solid Waste landfills

Tinet, Anne-Julie 29 September 2011 (has links)
Les Installations de Stockage des Déchets Non Dangereux modernes nécessitent pour satisfaire les enjeux environnementaux, sanitaire et / ou économiques une gestion contrôlée des effluents liquides et gazeux. Le travail réalisé dans cette thèse porte sur la compréhension et la modélisation numérique des phénomènes de transferts de fluides avec une attention particulière pour les différents procédés mis en oeuvre durant l'exploitation des sites (injection de liquide, récupération de liquide et gaz). Pour chacune des trois applications étudiées, les phénomènes physiques majeurs sont identifiés ainsi que les échelles de temps et d'espace associées de manière à pouvoir proposer des versions simplifiées d'un modèle général. Ceci permet en particulier de renseigner ces modèles par des données principalement expérimentales. Un attachement particulier est porté au caractère hétérogène et déformable du matériau déchet. La description fine de l'injection de lixiviat nécessite une description de type double milieu associée à un modèle d'écoulements préférentiels. Ce type d'écoulement est peu favorable à une augmentation de l'humidité du milieu en conditions gravitaires. Concernant le pompage, le milieu semble réagir comme un milieu homogène mais un comportement hystérétique spécifique au matériau est mis en évidence. Enfin, la prise en compte de la déformabilité du déchet conduit à la prédiction d'une structure d'écoulement originale lors du captage de biogaz. / Modern Municipal Solid Waste landfills require, in order to satisfy the environmental, sanitary and / or economical stakes, a controlled management of liquid and gaseous flows. This thesis work concerns the understanding and numerical modelling of fluid transfers considering especially various processes used during landfill site exploitation (liquid injection, liquid and gas recovery). For each of the three studied operational procedures, the major physical phenomena are identified as well as the time and space scales in order to define a simplified version of a general model. These choices aim at reducing the number of fitting parameters and at using mostly experimental characteristics. Particular attention is drawn towards the heterogeneous and deformable nature of waste material. The fine description of leachate injection requires a double medium description associated with a preferential flow model. The resulting flow behaviour makes difficult the increase in moisture content under gravitary conditions. For the pumping operation, the medium seems to have a homogeneous response. However, a specific hysteretic behaviour of the material is demonstrated. Finally, the consideration of waste deformability leads to the prediction of an original flow structure during the recovery of biogas.

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