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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.
311

As consequencias socio, economico e ambientais da troca do oleo combustivel por gas natural, na usina termoeletrica Piratininga

ZANCHETA, MARCIO N. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:51:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:59Z (GMT). No. of bitstreams: 1 11134.pdf: 13236915 bytes, checksum: bc82464227602708ec25d5d0daf70863 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
312

Avaliação de impactos cumulativos no planejamento ambiental de hidrelétricas na região amazônica: análise a partir dos instrumentos de avaliação de impacto aplicados na bacia do rio Teles Pires / Evaluation of cumulative impacts in environmental hydroelectric planning in the amazon region: analysis from the impact assessment instruments applied in the Teles Pires river basin

Silva, João Carlos da 22 February 2017 (has links)
Submitted by Nadir Basilio (nadirsb@uninove.br) on 2017-05-22T19:24:59Z No. of bitstreams: 1 Joao Carlos da Silva.pdf: 1112454 bytes, checksum: 0634c035319e68793998b75fbee7d282 (MD5) / Made available in DSpace on 2017-05-22T19:24:59Z (GMT). No. of bitstreams: 1 Joao Carlos da Silva.pdf: 1112454 bytes, checksum: 0634c035319e68793998b75fbee7d282 (MD5) Previous issue date: 2017-02-22 / The importance of preserving the Amazonian biome given its ecological relevance to the planet does not prevent the concentration of energy projects in the Amazon region due to its unique hydro potential. The hydrographic basins of the Amazon River, which includes the Teles Pires River and the Tocantins River, account for about 80% of the new hydroelectric plants planned to meet the demands of electricity in Brazil according to planning documents. The debate about the significant socio-environmental impacts associated with the advance of the hydroelectric frontier for the Amazon region has been intense. In the country since 2003, the hydroelectric sector, besides having their projects evaluated by the Environmental Impact Studies (EIS), also began to be discussed in the context of watersheds through the Integrated Environmental Assessment (IEA). Given the socio-environmental vulnerability of the Amazon region to the construction and operation of hydroelectric plants, it is relevant to discuss the cumulative impacts resulting from multiple hydroelectric plants in the same basin. The objective of this research is to study the environmental studies carried out in the Teles Pires river basin and three hydroelectric projects in this basin, respectively, the Teles Pires river basin IEA and the Colider Hydroelectric plant EIS, the Teles Pires Hydroelectric plant and the Sinop Hydroelectric plant. Thus, it is established as a research question: How the cumulative impacts of hydroelectric projects inserted in a hydrographic basin in the Amazon region are being analyzed in the environmental planning instruments through the Integrated Environmental Assessment and Environmental Impact Study? The general objective of the research is to analyze the evaluation of cumulative impacts from the Teles Pires river basin scale in the Amazon region to the hydroelectric scale by environmental impact assessment instruments applied to the environmental planning of hydroelectric dams. The results of the research show that there is an association between the cumulative impacts presented in the Integrated Environmental Assessment for the Teles Pires river basin and the Environmental Impact Studies of the uses inserted in this basin. The results also point out that the good practices of Cumulative Impact Assessment are present mainly at the river basin level. It is considered that the cumulative impacts of hydroelectric projects inserted in a hydrographic basin in the Amazon region are being analyzed in the environmental planning instruments, mainly through the Integrated Environmental Assessment of the basin and, to a lesser extent, through the Environmental Impact Study of Hydroelectric use. / A importância da preservação do bioma Amazônico dado sua relevância ecológica para o planeta não impede a concentração de projetos de energia na Amazônia motivados pelo seu singular potencial hídrico. As bacias hidrográficas do rio Amazonas, que abrange a do rio Teles Pires, e do rio Tocantins concentram cerca de 80% das novas usinas hidrelétricas previstas para atender as demandas de energia elétrica no Brasil segundo documentos do planejamento. O debate sobre os significativos impactos socioambientais associados ao avanço da fronteira hidrelétrica para a região amazônica tem sido intenso. No país, desde 2003, o setor hidrelétrico além de ter seus empreendimentos avaliados pelos Estudos de Impactos Ambiental (EIA) também passaram a ser discutidos no contexto de bacias hidrográficas por meio da Avaliação Ambiental Integrada (AAI). Dada a vulnerabilidade socioambiental da região amazônica frente à construção e operação das usinas hidrelétricas, torna-se relevante discutir os impactos cumulativos resultantes de múltiplos aproveitamentos hidrelétricos em uma mesma bacia. O objeto da pesquisa refere-se aos estudos ambientais realizados na bacia do rio Teles Pires e em seis aproveitamentos hidrelétricos nesta bacia, respectivamente, a AAI da bacia do rio Teles Pires e os EIAs da UHE Colider, da UHE Teles Pires, da UHE Sinop, da UHE Foz do Apiacás, da UHE São Manoel e da UHE Magessi. Assim, estabelece-se como questão de pesquisa: Como os impactos cumulativos de aproveitamentos hidrelétricos inseridos em bacia hidrográfica na região amazônica estão sendo analisados nos instrumentos de planejamento ambiental por meio da Avaliação Ambiental Integrada e Estudo de Impacto Ambiental? O objetivo geral da pesquisa refere-se a analisar a avaliação de impactos cumulativos desde a escala de bacia do rio Teles Pires na região amazônica até a escala de hidrelétricas por meio dos instrumentos de avaliação de impacto ambiental aplicados ao planejamento ambiental de hidrelétricas. Os resultados da pesquisa mostram que há associação entre os impactos cumulativos apresentados na Avaliação Ambiental Integrada para a bacia hidrográfica do rio Teles Pires e os Estudos de Impacto Ambiental dos aproveitamentos inseridos nesta bacia. Os resultados apontam ainda que as boas práticas de Avaliação de Impactos Cumulativos estão presentes sobretudo no nível de bacia hidrográfica. Considera-se que os impactos cumulativos de aproveitamentos hidrelétricos inseridos em bacia hidrográfica na região amazônica vêm sendo analisados nos instrumentos de planejamento ambiental, principalmente, por meio da Avaliação Ambiental Integrada da bacia e, em menor proporção, por meio do Estudo de Impacto Ambiental do aproveitamento hidrelétrico.
313

A Câmara Municipal de Juiz de Fora no período autoritário (1964-1985): impactos sobre a instituição e a dinâmica político-eleitoral

Oliveira, Bárbara Vital de Matos 02 October 2016 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-20T17:46:12Z No. of bitstreams: 1 barbaravitaldematosoliveira.pdf: 2095013 bytes, checksum: f18f67a406e7bb2a5ec40094c835beb7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-21T13:25:18Z (GMT) No. of bitstreams: 1 barbaravitaldematosoliveira.pdf: 2095013 bytes, checksum: f18f67a406e7bb2a5ec40094c835beb7 (MD5) / Made available in DSpace on 2017-03-21T13:25:18Z (GMT). No. of bitstreams: 1 barbaravitaldematosoliveira.pdf: 2095013 bytes, checksum: f18f67a406e7bb2a5ec40094c835beb7 (MD5) Previous issue date: 2016-10-02 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A presente pesquisa tem como objeto de investigação o Poder Legislativo Municipal durante o período do regime autoritário de 1964-1985 no Brasil, tendo como caso de estudo a Câmara Municipal de Juiz de Fora, Minas Gerais. Assim, buscou-se analisar: o que ocorreu com a Câmara Municipal em questão após o golpe de 1964 e a consequente instituição de um novo regime, de caráter autoritário, e; quais foram as alterações institucionais sobre a ordem jurídica e política e sobre o sistema político-partidário e eleitoral. As dimensões de análise mobilizadas no estudo são as dimensões institucional, eleitoral e política, organizacional e de produção legislativa. A dissertação se desenvolve em três capítulos. O Capítulo I disserta sobre os primeiros impactos do golpe de 1964 e do novo regime inaugurado por este evento sobre a cidade e a Câmara Municipal de Juiz de Fora. O Capítulo II aborda as alterações na ordem jurídica e política no plano formal, investigando se tais alterações impactaram, e de que maneira, o Legislativo municipal na prática. O Capítulo III é dedicado à análise das eleições municipais para os cargos do Executivo e do Legislativo, bem como a competição e a dinâmica eleitorais e partidárias do município. Para tal exercício, foram utilizadas diferentes técnicas de pesquisa: (a) a análise documental, tendo como fontes o jornal local Diário Mercantil, as Atas das Sessões da Câmara Municipal de Juiz de Fora, os processos de produção legislativa, as leis federais do período, como os Atos Institucionais, a Constituição de 1967, a Emenda Constitucional nº 1, de 1969, entre outros; (b) a análise de dados, tais como dados eleitorais das eleições municipais que ocorreram entre 1962 e 1982, informados pelo Tribunal Superior Eleitoral e pelo periódico Diário Mercantil, e dados de produção legislativa disponibilizados pelo arquivo digital e o arquivo físico da Câmara Municipal de Juiz de Fora e; (c) a análise de discurso por meio de entrevistas realizadas com vereadores que exerceram mandato à época. / The present study has as investigation object the Municipal Legislature during the period of the authoritarian regime of 1964-1985 in Brazil, taking the Municipal Council of Juiz de Fora, Minas Gerais, as a case study. Thus, it was sought to analyze: what happened to the Municipal Council in question after the 1964 coup and the consequent establishment of a new authoritarian regime of permanence; and what the institutional changes on the legal and political order and the political party and electoral system were. The analysis dimensions mobilised in the study are the institutional dimensions, electoral and political, organizational and legislative production. The dissertation develops in three chapters. Chapter I discourses on the early impacts of the 1964 coup and the new regime inaugurated by this event over the city and the Municipal Council of Juiz de Fora. Chapter II addresses the changes in law and policy in the formal level, investigating whether and how these changes impacted the Municipal Council in practice. Chapter III is devoted to analysis of municipal elections for the positions of the executive and legislative, as well as competition and the electoral and party dynamics of the municipality. For such practice, many different research techniques were used: (a) the documentary analysis, with the local newspaper sources Diário Mercantil, the Minutes of Proceedings of the Municipality of Juiz de Fora, the legislative production processes, federal law period as the Institutional Acts, the 1967 Constitution, the Constitutional Amendment No. 1, 1969, among others; (b) the analysis of data such as electoral data of the municipal elections that took place between 1962 and 1982, informed by the Superior Electoral Court and the periodic Mercantile Journal, legislative and production data provided by the digital file and the physical file of the Municipality of Juiz de Fora; and (c) discourse analysis through interviews with councilors who were in office at the time.
314

Diagnóstico dos impactos socioambientais urbanos em Itacaré (BA) / Diagnosis of urban environmental and social impacts on Itacare (Bahia)

Ferreira, Paula Fabyanne Marques, 1978- 10 June 2011 (has links)
Orientador: Lindon Fonseca Matias / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-19T10:53:15Z (GMT). No. of bitstreams: 1 Ferreira_PaulaFabyanneMarques_M.pdf: 9800598 bytes, checksum: 2c254d2a94d8c5a83bcc51c72bc125d0 (MD5) Previous issue date: 2011 / Resumo: Este trabalho visa contribuir com o conhecimento sobre a dinâmica de produção do espaço geográfico na cidade de Itacaré, localizada na região cacaueira do estado da Bahia, Brasil. A emergência da cidade como polo turístico e sua perspectiva de desenvolvimento econômico tem ampliado a atratividade local e, por conseguinte, a pressão demográfica. A crescente urbanização, a especulação imobiliária, a falta de planejamento e o intenso fluxo de turistas têm desencadeado processos que afetam toda a relação entre a sociedade e o espaço natural, causando uma série de impactos socioambientais. A metodologia teve como principal estratégia a espacialização dos principais impactos, considerando as características físicas e sociais da área em estudo. Além do levantamento e revisão bibliográfica, foram realizadas visitas em campo, coleta de informações em órgãos oficiais, realização de mapeamentos temáticos, entrevistas com moradores locais, turistas e representantes públicos, análise de imagens de satélite da área de estudo e elaboração da base de dados georreferenciados, enfocando os principais impactos socioambientais urbanos. O presente diagnóstico adverte uma situação de expansão urbana voltada para o turismo sem um planejamento estratégico, que está gerando crescentes impactos socioambientais e a degradação da qualidade de vida local, especialmente dos segmentos mais pobres da população / Abstract: This paper intends to contribute to knowledge about the dynamics of production of geographical space in the town of Itacare, located in the cocoa region of Bahia, Brazil. The emergence of the city as a tourist hub and its outlook for economic development has increased the local attraction and, consequently, the demographic pressure. Increasing urbanization, real state speculation and massive flow of tourists have unleashed processes that affect the entire relationship between society and the natural space, causing a series of socio-environmental impacts. The methodology had as the most strategy, the spatialization and integration of these socio-environmental attributes, considering the physical and social characteristics of the study area. In addition to the survey and literature review, visits were made in the field, collecting information in official establishments, conducting thematic mapping, interviews with local residents, tourists and government officials, analysis of satellite images of the study area and development of georeferenced database, focusing on the major urban socio-environmental impacts. This diagnostic warns a situation of urban sprawl devoted to tourism, without a strategic planning are causing socio-environmental impacts and degradation of quality of local life, especially for the poorest segments of the population / Mestrado / Análise Ambiental e Dinâmica Territorial / Mestre em Geografia
315

Youth Tourism : – Impacts on places from a consumer perspective

Blomgren, Elin, Ljungström, Sofie January 2018 (has links)
Although youth tourism is an increasingly relevant subject little research have been done regarding the segment’s own perception of their impacts. A consumer perspective was assumed to examine in what ways youth tourism impact places. This study adopts a deductive approach reviewing existing literature regarding youth tourism, impact and place. A case study concerning how youth travellers perceive and evaluate their own impacts was conducted using mixed-methods. Data sources include a survey and in-depth interviews concerning sociocultural, economic, and environmental items. The study concludes that what impacts youth tourism has on places are subject to the place’s current state and ability to host youth travellers. The number of youth travellers and their behaviour determines the local and global sociocultural, economic and environmental impacts that youth tourism has on places. This paper is considered a pre-study that contributes to the development of theory regarding youth tourism.
316

Evolution du cycle hydrologique continental en France au cours des prochaines décennies / Evolution of the continental hydrological cycle over France in the coming decades

Dayon, Gildas 20 November 2015 (has links)
L'étude des impacts du changement climatique demande souvent de mettre en place de longues chaînes de modélisation. Du modèle qui servira à estimer les concentrations futures en gaz à effet de serre jusqu'au modèle d'impact. Tout au long de cette chaîne de modélisation, les sources d'incertitudes s'accumulent et compliquent l'exploitation des résultats pour l'élaboration de stratégies d'adaptation. Il est proposé ici d'évaluer les impacts du changement climatique sur le cycle hydrologique en France ainsi que les incertitudes qui y sont associées. La contribution de chacune des sources d'incertitudes n'est pas abordée, principalement celle associée aux scénarios d'émission de gaz à effet de serre, aux modèles climatiques et à la variabilité interne. Nous proposons dans ce travail une approche pour évaluer la transférabilité dans un climat futur de la méthode statistique de régionalisation des simulations climatiques. La vérification de l'hypothèse de transférabilité effectuée est l'une des principales sources d'incertitudes des méthodes statistiques de régionalisation. L'évaluation proposée ici s'appuie sur l'utilisation de modèles régionaux, dans un cadre dit de modèle parfait, et permet de montrer que l'utilisation de certain prédicteurs s'avèrent utile à assurer la transférabilité de la méthode de régionalisation dans un climat futur. Cette approche proposée pour une méthode de désagrégation statistique est également applicable à des méthodes de correction des biais des modèles régionaux. Les récentes réanalyses atmosphériques sur l'ensemble du XXème siècle, régionalisées avec la méthode développée dans ce travail, et associées aux observations de température et précipitations permettent de caractériser le cycle hydrologique en France. Elles permettent notamment de montrer que la variabilité multi-décennale des débits observés pendant le XXème siècle est généralisée à l'ensemble du pays et est liée à la variabilité des conditions atmosphériques. Cette variabilité multi-décennale des débits est généralement plus faible dans les simulations hydrologiques réalisées avec les simulations historiques des modèles climatiques. Les projections climatiques ont été régionalisées avec la méthode développée dans ce travail. La température sur l'ensemble du pays, en moyenne sur les modèles climatiques, augmente jusqu'à 3,5°C en hiver et 6,5°C en été d'ici la fin du siècle. Les précipitations vont diminuer sur l'ensemble du pays en été, de presque moitié sur le sud du pays pour le scénario le plus sévère. En hiver, elles augmentent sur la moitié nord du pays et diminuent légèrement sur la partie sud. Dès les prochaines décennies, la diminution des précipitations est importante en été, l'évolution est moins marquée pour les autres saisons. Enfin, les résultats des projections hydrologiques réalisées avec un modèle hydrologique et un ensemble de modèles climatiques sont présentés pour les prochaines décennies et également pour la fin du XXIème siècle. Sur la Seine, les résultats sont différents en hiver de ceux présentés dans de précédentes études. Ici, les précipitations et les débits augmentent en hiver et diminuent en été sur ce bassin versant. Ailleurs en France, les résultats convergent avec les études précédentes, à savoir une augmentation de l'évapotranspiration, une diminution généralisée des débits et un assèchement des sols. L'incertitude due aux modèles climatiques et à la variabilité interne sur les changements relatifs de débits augmente systématiquement pendant le XXIème siècle, jusqu'à atteindre plus de 20% en hiver pour le scénario le plus sévère. Dans les prochaines décennies, l'incertitude due uniquement à la variabilité interne sur les changements de débits est aussi forte que l'incertitude due aux modèles climatiques et à la variabilité interne. Dès les prochaines décennies, les changements de débits annuels sont plus forts sur la Loire, la Garonne et le Rhône que les changements maximaux observés pendant le XXème siècle. / The assessment of the impact of climate change often requires to set up long chains of modeling, from the model to estimate the future concentration of greenhouse gases to the impact model. Throughout the modeling chain, sources of uncertainty accumulate making the exploitation of results for the development of adaptation strategies difficult. It is proposed here to assess impacts of climate change on the hydrological cycle over France and associated uncertainties. The contribution of each sources of uncertainty is not addressed, mainly that associated with greenhouse gases emission scenario, climate models and internal variability. In the context of impacts of climate change on the hydrological cycle over France, it is possible to ask what is the contribution of each sources of uncertainty to the total uncertainty associated with mean changes. Is it possible to reduce, and if so how, the contribution of one source or another ? We propose in this work an approach to assess the transferability in the future climate of a statistical method to downscale climate simulations. The transferability assumption is one the main sources of uncertainty in statistical downscaling method. The assessment suggested here relies on the use of regional climate models, in a perfect model framework, and shows that some predictors are useful to ensure the transferability of the downscaling method in the future climate. This framework, proposed for a statistical downscaling method, is also applicable to bias correction methods in regional climate models. Recent atmospheric reanalyses of the 20th century are downscaled with the method developed in this work, associated with observations of temperature and precipitation. The hydrological cycle over France is characterized with these reconstructions. We show that the multi-decadal variability of observed streamflows during the 20th century is generalized to the whole country and is partly due to atmospheric variability. This multi-decadal variability of streamflows is generally weaker in hydrological simulations done with historical simulations from climate models. The climate projections have been downscaled with the method developed in this work. The temperature on the country, on average over climate models, could increased by 3,5°C in winter and 6,5°C in summer in the course of this century. Precipitations will decrease all over the country in summer, nearly by half on southern part of France for the most severe scenario. In winter, precipitations will increase in the northern part of the country and will decrease slightly in the southern part. In the next few decades, the decrease in precipitation is important in summer, and changes are less pronounced for other seasons. Results of hydrological projections done with one hydrological model and an ensemble of climate models are presented for the coming decades and for the end of the century. On the Seine river, results slightly differ in winter from those presented in previous studies. Here, precipitations and streamflow increase in winter and decrease in summer on that river basin. Elsewhere in France, results are consistent with previous studies, namely an increase in evapotranspiration, a decrease in streamflow and much drier soil. The uncertainty due to both climate models and internal variability on relative changes in streamflows always increase during the 21st century, to over 20% in winter for the most severe scenario. In the coming decades, the uncertainty due to internal variability only on streamflow changes is as strong as the uncertainty due to both climate models and internal variability. In the coming decades, annual streamflow changes of the Loire, Garonne and Rhône rivers are stronger than the maximum changes observed during the 20th century.
317

Simulation of cold spray particle deposition process / Simulation de la procédure de dépôt des particules par pulvérisation à froid

Xie, Jing 27 May 2014 (has links)
La projection à froid est une technologie en plein essor pour le dépôt de matériaux à l'état solide. Le procédé de dépôt des particules par pulvérisation à froid est simulé par la modélisation de l'impact à haute vitesse de particules sphériques sur un substrat plat dans diverses conditions. Pour la première fois, nous proposons une approche numérique par couplage Euler-Lagrange (CEL) afin de résoudre ce problème à haute vitesse de déformation. Les capacités de l'approche numérique CEL pour la modélisation du processus de dépôt de projection à froid sont évaluées par une étude paramétrique de : la vitesse d'impact, la température initiale des particules, le coefficient de frottement et le choix des matériaux. Les résultats de la simulation à l'aide de l'approche numérique CEL sont en accord avec les résultats expérimentaux publiés dans la littérature. La méthode CEL est généralement plus précise et plus robuste dans des régimes de déformations élevées. Un nouveau modèle d'empilement de type CFC, inspiré de la structure cristalline, est construit afin d'étudier le taux de porosité des particules déposées et les contraintes résiduelles dans le matériau de substrat pour diverses conditions. Nous pouvons observer non seulement la géométrie 3D de porosités, mais aussi leur répartition et leur évolution pendant les impacts successifs. Pour les particules, une vitesse d'impact et une température initiale élevées, sont des avantages pour produire des revêtements denses par projection à froid. Des contraintes résiduelles de compression existent à l'interface entre les particules et le substrat. Ces dernières sont causées par les grandes amplitudes et vitesses de déformation plastique induites par le procédé. Un second modèle moins complexe pour la modélisation de l'impact multiple oblique a été créé afin de simuler l'érosion de surface. Une forte érosion de surface est le résultat : d'une plus grande vitesse d'impact, d'un coefficient de frottement élevé et d'un angle de contact réduite. Pour un matériau ductile comme le cuivre, il y a deux modes de rupture : le mode 1 de traction et le mode 2 de rupture par cisaillement. Le premier survient principalement en dessous de la surface du substrat et à la périphérie de impacts, tandis que le second intervient de manière prédominante à la surface des impacts. On observe quatre étapes lors de la propagation des fissures : la formation de porosités, de fissures, la croissance de ces dernières, puis une dernière étape de coalescence et rupture. Un critère simple, où la vitesse d'érosion est fonction de l'angle de contact et de la vitesse critique d'érosion lors d'un impact de vitesse normale , est proposé sur la base des résultats des simulations afin de prédire l'initiation de l'endommagement. La déformation plastique équivalente est également un paramètre clef pour identifier l'initiation de l'endommagement, une valeur critique de 1,042 a été trouvée dans notre étude pour le cuivre. / Cold spray is a rapidly developing coating technology for depositing materials in the solid state. The cold spray particle deposition process was simulated by modeling the high velocity impacts of spherical particles onto a flat substrate under various conditions. We, for the first time, proposed the Couple Eulerian Lagrangian (CEL) numerical approach to solve the high strain rate deformation problem. The capability of the CEL numerical approach in modeling the Cold Spray deposition process was verified through a systematic parameter study, including impact velocity, initial particle temperature, friction coefficient and materials combination. The simulation results by using the CEL numerical approach agree with the experimental results published in the literature. Comparing with other numerical approaches, which are Lagrangian, ALE and SPH, the CEL analyses are generally more accurate and more robust in higher deformation regimes. Besides simulating the single particle impact problem, we also extended our study into the simulation of multiple impacts. A FCC-like particles arrangement model that inspired by the crystal structure was built to investigate the porosity rate and residual stress of deposited particles under various conditions. We observed not only the 3D profiles of voids, but also their distributions and developments during different procedures. Higher impact velocity and higher initial temperature of particles are both of benefit to produce a denser cold spray coating. The compressive residual stresses existed in the interface between the particle and substrate is mainly caused by the large and fast plastic deformation. Another simplified model for multiple impacts was created for the simulation of surface erosion. A severe surface erosion is the result of a high impact velocity, a high friction coefficient and a low contact angle. Two element failure models suitable for high-strain-rate dynamic problems were introduced in this study. For a ductile material as Copper, it followed two fracture modes in our study, which are tensile failure mode and shear failure mode. The former one mainly occurred beneath the substrate surface and the periphery of substrate craters, nevertheless the latter one was found predominately at the surface of craters. Four steps were found during the propagation of crack: void formation; crack formation; crack growth; coalescence and failure. A simple criterion equation was derived based on the simulation results for predicting the initiation of damage, which the erosion velocity v_{ero} is a function of contact angle and erosion velocity for normal impact v_{pi/2}. The equivalent plastic strain could also be a parameter for identifying the onset of damage, identified as being 1.042 for Copper in our study.
318

Modélisation du fonctionnement hydrologique du sol et de la biodiversité des communautés végétales. Application à l'analyse de la performance écologique d'un aménagement paysager autoroutier. / Using the modeling approaches of soil water transfers and plant communities biodiversity to analyse the ecological performance of a highway mitigation project.

Mayrand, Flavie 06 December 2012 (has links)
L'anthropisation croissante des territoires a conduit à la transformation profonde des écosystèmes et à une perte massive, rapide et irréversible de la biodiversité. La réglementation nationale française impose aujourd'hui aux aménageurs du territoire d'évaluer, a priori et a posteriori, les impacts environnementaux de leurs projets de construction (ex : infrastructures routières) et notamment les impacts sur la biodiversité. Cette réglementation impose également de proposer des mesures d'évitement, de réduction, et de compensation, lorsqu'il existe des impacts résiduels, par la création ou la restauration de la biodiversité dégradée. En l'absence d'outils performants à disposition des gestionnaires, les échecs de la prédiction des impacts et de l'évaluation de l'efficacité des mesures conservatoires sont nombreux. L'objectif général de cette thèse est de proposer une nouvelle approche méthodologique pour (i) caractériser les processus et les paramètres abiotiques impactant la diversité végétale des communautés, (ii) analyser l'efficacité d'un projet de création et (iii) proposer, à la lecture de ces résultats, des nouvelles mesures de valorisation de la biodiversité végétale du site d'étude. Le site étudié est un aménagement paysager autoroutier, au sein duquel des semis et des plantations ont été réalisées par le constructeur, deux ans avant le début de notre étude. Nous avons restreint l'étude mécaniste du compartiment abiotique à celle du fonctionnement hydrologique (modélisé à l'aide d'HYDRUS-1D). [...] Suite et fin du résumé dans la thèse. / Human activities are responsible for high modifications in ecosystems functioning. It is recognized that these impacts cause definitive and high losses rate of biodiversity in every components of wildlife. Due to regulation, construction companies are bound to evaluate environmental impacts of the infrastructure construction projects (eg: roads), and more particularly, impacts on biodiversity. Companies are also bound to propose measures to avoid, reduce or mitigate residuals impacts by the creation or restoration planning of biodiversity. Unfortunately, there are not existing tools and methods clearly defined by regulation for such plans. Most of the time, predictions and environmental evaluations fail in measuring the impacts on biodiversity and efficiency of conservation planning. The research program that we conducted aimed at (i) proposing a new methodological approach in order to characterise processes and abiotic parameters which impact biodiversity of plant communities, (ii) analysing conservatory plans efficiency and (iii) proposing measures for biodiversity valuation in our study case. Our study was realised in a landscaping project zone along the A19 highway, Loiret, France. Seedling and planting were done two years before our study began. Only hydrological processes were studied based on mechanistic modelling using Hydrus-1D software. Last and final summary in the thesis.
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Evaluation environnementale des options de recyclage selon la méthodologie d’analyse de cycle de vie : établissement d’une approche cohérente appliquée aux études de cas de l’industrie chimique / Environmental evaluation of recycling options according to the life cycle assessment methodology : establishment of a consistent approach applied to case studies from the chemical industry

Schrijvers, Dieuwertje 14 March 2017 (has links)
La modélisation du recyclage - et l'allocation en général - est un sujet très débattu dans le domaine de l’analyse du cycle de vie (ACV). Cette thèse a pour objectif le développement d’une approche scientifique et cohérente pour la modélisation du recyclage en ACV afin de fournir des informations pertinentes aux entreprises. Ainsi, un cadre systématique est établi pour catégoriser les procédures d'allocation existantes en fonction de l’objectif de l’ACV et de l’approche attributionelle (ACV-A) ou conséquentielle (ACV-C). Une revue critique des directives officielles a montré qu'aucun d'entre elles ne recommande des procédures d’allocation conforme à ce cadre. L’approche d’imputation basée sur un schéma axiomatique qui explicite toute hypothèse subjective a été identifiée comme la méthode la plus pertinente pour l’ACV-A. Dans le cas de l'ACV-C, le ratio entre le prix du marché du matériau recyclé et celui du matériau primaire substitué est présenté comme un nouvel indicateur pour identifier si le recyclage permet de substituer la production de matériau primaire ou d’éviter son traitement en tant que déchet. Les processus qui sont affectés par une demande changeante pour un produit sont identifiés avec un diagramme de boucle causale, qui inclut également les stocks anthropiques comme un nouvel élément dans l’ACV-C. L'application des procédures d’allocation est démontrée par une étude de cas portant sur le recyclage des éléments de terres rares (ETR) des lampes fluorescentes. Les deux approches d’ACV fournissent des informations différentes et utiles aux entreprises. / Modeling of recycling – and allocation in general – is a heavily debated topic in the Life Cycle Assessment (LCA) domain. This thesis aimed to find a coherent scientific approach to model recycling in LCA that provides relevant information to companies. Existing allocation procedures are captured by mathematical formulas and linked to an LCA goal and an attributional or consequential approach in a systematic framework. A review of official guidelines showed that none of them provides recommendations on allocation that is consistent with this framework. A partitioning approach was identified for attributional LCA (a-LCA). This approach is based on subjective assumptions, which are made explicit by axioms. In consequential LCA (c-LCA), the market-price ratio between the recycled and substituted primary material is introduced as a new indicator to identify whether additional recycling substitutes the production of primary materials or avoids waste treatment. The processes that are affected by a changing demand for a product are identified by a causal loop diagram, which also includes stockpiling as a new element in c-LCA. The application of the allocation procedures is demonstrated by a case study of the recycling of rare earth elements (REEs) from used fluorescent lamps. The a-LCA indicated that recycled REEs are more sustainable than primary REEs. The c-LCA showed that recycling is environmentally beneficial as long as the REEs are used in fluorescent lamps that substitute less energy-efficient halogen lamps. This demonstrates that both LCA approaches provide different but useful information for companies. Suggestions are given for policy measures when the market situation does not stimulate environmentally beneficial behavior. It is recommended, among other options, to extend the causal loop diagram of c-LCA to include additional mechanisms, such as rebound effects.
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Production sonore des invertébrés benthiques d’habitats côtiers tempérés : diversité et utilisation potentielle en écologie marine / Sound production of benthic invertebrates from temperate coastal habitats : diversity and potential use in marine ecology

Coquereau, Laura 06 December 2016 (has links)
La production sonore biologique, étudiée par acoustique passive, doit être évaluée comme méthode complémentaire pour l’étude des effets des perturbations anthropiques sur les milieux côtiers.Alors que les sons émis par les mammifères marins et les poissons sont largement documentés, ceux issus des invertébrés benthiques restent peu décrits, même si ces derniers peuvent assurer des fonctions-clés dans les systèmes marins. L’enjeu principal de cette thèse était d’évaluer la pertinence de l’utilisation de l’acoustique passive comme outil écologique en s’appuyant sur la biophonie des invertébrés benthiques d’habitats côtiers tempérés et plus particulièrement en prenant comme habitat-modèle les bancs de maërl de la rade de Brest. Nous avons mis en évidence l’existence d’espèces sonifères remarquables qui constituent de bons candidats pour leur suivi en milieu naturel. Ces travaux ont de plus montré l’importante contribution de certains invertébrés benthiques dans le paysage sonore sous-marin, encourageant à ne plus imputer systématiquement les sons benthiques uniquement aux « crevettes claqueuses ». Le deuxième volet de cette thèse a montré que les variations de production sonore des invertébrés benthiques, à l’échelle individuelle ou collective, offrent des informations précieuses sur la mise en évidence de stress tels qu’un bloom d’algues toxiques ou l’impact du dragage. Ainsi, le nombre de mouvements sonifères des coquilles Saint-Jacques est doublé en présence de fortes concentrations d’algues toxiques, et le paysage sonore des bancs de maërl fortement pêchés est trois fois plus silencieux et moins complexe que celui du maërl préservé. Les résultats de ce travail de thèse, discutés dans un contexte de développement d’outils pour l’évaluation de l’état de santé des écosystèmes marins, permettent l’émergence de nouvelles hypothèses de travail en écologie marine. / Biological sound production, as studied by passive acoustics, should be considered as a complementary method to study the effect of anthropogenic disturbances on coastal systems. While sounds emitted by marine mammals and fish are well documented, those from benthic invertebrates are poorly described, although they can play key roles in marine ecosystems. The main goal of this PhD work was to evaluate the suitability of passive acoustics as an ecological tool based on sound production by benthic invertebrates living in temperate coastal habitats, and particularly in maerl beds of the Bay of Brest.We highlighted the existence of interesting soniferous species that appear to be good candidates to monitor in the field. This work also showed the important contribution of some benthic invertebrates to the underwater soundscape, suggesting that benthic sounds should not be attributed only to snapping shrimps. The second part of this PhD thesis emphasized that changes in benthic invertebrate sound production, at individual or collective scales, provides valuable information on the detection of stress such as a toxic algal blooms or the impact of dredging. Thus, the number of soniferous movements made by the great scallop doubles in the presence of high concentrations of toxic algae, and the soundscape of heavily fished maerl beds is three times quieter and less complex than preserved ones. The results of this PhD thesis, which are discussed in the context of tool development for the assessment of marine ecosystem health, raise new working hypotheses in marine ecology.

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