Nous décrivons dans ce travail l’élaboration de latex nanocomposites à base d’oxyde de cérium en vue d’applications dans le domaine des revêtements. Deux procédés originaux ont été développés afin de contrôler la morphologie des particules. Dans un premier temps, nous avons tiré parti de la forte densité de charges des nanoparticules d’oxyde de cérium pour stabiliser des particules de latex obtenues par polymérisation en émulsion ou en miniémulsion « de Pickering ». Dans les deux cas, la réaction est conduite en présence des particules inorganiques et d’un agent complexant à caractère acide, l’acide méthacrylique, en l’absence de tout tensioactif. Des particules de latex, décorées en surface par les nanoparticules d’oxyde de cérium ont été ainsi synthétisées. Par la suite, une stratégie qui consiste à utiliser des chaînes de polymères hydrophiles, réactivables (macro-agent RAFT) et préalablement adsorbées à la surface des nanoparticules d’oxyde de cérium a été envisagée. Ces chaînes polymères comportant à la fois des fonctions carboxyliques et un groupe trithiocarbonate terminal sont capables de stabiliser la suspension colloïdale des nanoparticules et de réamorcer la polymérisation en mode semi-continu permettant ainsi l’encapsulation de l’oxyde de cérium. Une optimisation visant à utiliser un procédé batch a également été évaluée. Quelle que soit la stratégie employée, une attention toute particulière a été portée à la stabilité colloïdale du milieu ainsi qu’à la cinétique de la réaction. La morphologie des particules composites a été caractérisée par MET et cryo-MET et reliée aux conditions de modification de surface et de polymérisation / This work describes the elaboration of nanocomposite latexes containing cerium dioxide nanoparticles for coating applications. Two original approaches have been developed to control the particle morphology. First, we took advantage of the high charge density of cerium dioxide nanoparticles to stabilize latex particles obtained via emulsion or “Pickering” miniemulsion polymerization. In both cases the reaction was conducted in the presence of the inorganic particles and methacrylic acid as a complexing agent, in the absence of any added surfactant. Armored latex particles covered with cerium dioxide nanoparticules were obtained by this method. Subsequently, another approach based on the use of living hydrophilic polymer chains (macroRAFT agents) previously adsorbed on the surface of the cerium dioxide nanoparticles was considered. These copolymers both containing carboxylic acid groups and carrying a thiocarbonylthio end group led to stable aqueous dispersion of the nanoparticles and could chain extend to form an encapsulating polymer shell under starved feed emulsion polymerization conditions. An optimization using a batch process was also evaluated. For both approaches, particular attention was paid to the colloidal stability of the medium and to the kinetics of the reaction. The morphology of the nanocomposite latex particles was characterized by TEM and cryo-TEM and correlated with the surface modification and the experimental conditions

L'économie moderne complexifiée, qui résulte d'une société humaine hétérogène, oblige les économistes et les décideurs à élaborer des modèles économiques complexes. Outre cette complexité, les politiques économiques varient d’un pays à l’autre.Cette thèse aborde ces complexités des économies modernes.Dans les trois premiers chapitres de cette thèse, j'améliore les théories existentes pour évaluer le rôle des agents intermédiaires financiers, des marchés d'immobilier et du crédit dans l'économie, en utilisant des modèles d’Équilibre Général Dynamique et Stochastique (EGDS). Les données de trois périodes de l’économie américaine, y compris le climat économique avant la Grande Récession, l’effondrement systémique de 2008 et les politiques budgétaires après la crise, sont imputés aux modèles. Les modèles EGDS ont souvent été critiqués pour leur trop grande simplification des marchés financières.J'ai inclus les frictions financières des différents côtés de l'économie pour résoudre les échecs des modèles précédents.Les résultats des simulations indiquent que l'introduction de ces nouvelles caractéristiques dans l'économie révèle de nouveaux canaux et mécanismes qui sont négligés dans les modèles simples. Par conséquent, mon modèle donne un moyen plus précis de prévoir les mouvements économiques. En outre, cette thèse documente l’importance des réglementations des politiques macroprudentielles dans la stabilité financière, la durabilité et le bien-être. Enfin, dans les deux derniers chapitres de ma thèse, j’aborde l’étude des marchés avancés et je me concentre sur les économies en développement.Ces chapitres construisent de nouveaux modèles et abordent diverses questions économiques relatives à l'économie financière, publique et du travail dans les pays en développement, à travers le prisme des modèles EGD à agents hétérogènes.J'examine les impacts des chocs réels, monétaires, fiscaux et pétroliers sur l'environnement économique des pays en développement. Je propose ensuite des recommandations de politique économiques. / The modern economy, which is a result of intricate human society, compels economists and policy makers to build complex economic models. In addition to this complexity, each country requires its own economic policies. This thesis addresses these intricacies of modern economies. In the first three chapters of this thesis, I improve the current literature to assess the role of financial intermediary agents, housing and credit markets in the economy, using Dynamic Stochastic General Equilibrium (DSGE) models. Data from three periods in the US economy, including the economic climate before the Great Rescission, the systemic collapse in 2008, and post-crisis fiscal policies, are imputed into the models. Simple DSGE models havebeen criticized for not placing more emphasis on financial frictions. Here, I have included financial frictions on different sides of economy to resolve the failures of previous models.The results of simulations indicate that introducing these features to the economy reveals new channels and mechanisms which are neglected in simple models. As a result, my model gives a more accurate means to forecast economic movements. In addition, this thesis documents the significance of macroprudential policy regulations in financial stability, sustainability and welfare. Lastly, in the final two chapters of my thesis, I move away from the study of advanced markets and focus on developing economies. These chapters build new models and address a variety of economic questions pertaining to financial, public and labor economics in developing countries, through the lens of multi-agent dynamic general equilibrium models. I examine the impacts of real, monetary, fiscal and oil price shocks on the economic environment of developing countries. I then propose appropriate policy recommendations.

La competencia comunicativa exigida en el mundo empresarial actual y el papel que el inglés juega como lengua de comunicación internacional constituyen la base de la proliferación investigadora en los géneros del inglés académico y profesional (IPA), y en especial del inglés de los negocios (IN). Este desarrollo también tiene su efecto en la producción de materiales docentes, y en menor medida en lo referente a la investigación aplicada al aula del IN. Nuestra aportación a dicho campo se fundamenta en el estudio de un género discursivo escrito particular del mundo de los negocios: el informe empresarial. Pretendemos explicar su concepción como género, así como su relevancia y aportaciones en el aula del inglés de especialidad. Demostraremos cómo este género incluye múltiples características del discurso escrito del IN y observaremos a través del estudio empírico que su implementación en el aula ayuda a desarrollar de forma pertinente ciertos elementos (macro)estructurales y discursivos.

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-10-20Bitstream added on 2014-06-13T20:26:43Z : No. of bitstreams: 1 vasconcelos_ts_dr_rcla.pdf: 935003 bytes, checksum: 9e031857a43c3323cfda884a7640bbdf (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A região ocidental do estado de São Paulo abriga a maior área contínua remanescente da Floresta Estacional Semidecidual Atlântica que recobria esta região. Grande parte desta região está protegida no Parque Estadual do Morro do Diabo (PEMD), considerada insuficientemente conhecida, mas de provável importância biológica em relação a herpetofauna. O presente estudo objetivou-se por estudar os padrões de distribuição espacial e temporal da anurofauna do PEMD, e também verificar como a heterogeneidade dos corpos d’água influencia na composição e riqueza de espécies de anfíbios. De maneira geral, as espécies de anfíbios registradas no PEMD (tanto adultos em atividade de vocalização quanto girinos) ocorreram diferentemente entre os variados tipos de corpos d’água amostrados, sendo principalmente relacionado com tipo de correnteza e hidroperíodo dos corpos d’água. Assim, a composição da anurofauna foi diferente entre corpos d’água lóticos, lênticos permanentes/semi-permanentes e lênticos temporários. A ocorrência temporal das espécies foi restrita aos meses quente e úmido do ano (com exceção de uma espécie que ocorreu durante os meses frio e seco), o que resultou em alta sobreposição temporal no período de vocalização dos machos e ocorrência de girinos. Grupos de espécies ocorreram diferentemente ao longo dos meses quente e úmido, com espécies características de início, meio e fim da estação chuvosa. A análise macro-espacial da distribuição da anurofauna no PEMD evidenciou uma baixa similaridade entre as diferentes fitofisionomias amostradas. Na verdade, esta baixa similaridade faunística foi consequência da baixa eficiência de captura das armadilhas de interceptação e queda, o que resultou em uma baixa riqueza de espécies nas fitofisionomias estudadas. No entanto, alta similaridade na composição de espécies foi encontrada... / Occidental region of São Paulo state shelters the largest continuous remnant of Mesophytic Semideciduous Forest (Atlantic domain). Most of this region is legally protected by the Morro do Diabo State Park (MDSP), considered insufficient known but with probable biological importance concerning amphibians and reptiles. The present study aimed to study the spatio-temporal patterns of anuran distribution at MDSP, as well as to verify how environmental heterogeneity of breeding ponds influences on richness and anuran species composition. In general, recorded species (either calling males or tadpoles) occurred differentially among the studied breeding habitats, which was mainly related to the water flow and hidroperiod of breeding habitats. Thus, lotic, lentic permanent/semipermanent, and lentic temporary breeding habitats presented different anuran species composition. Temporal distribution of individuals was restricted to the moist and hot months (with exception to one species that occurred during the dry and cold months), resulting in a high temporal overlap of calling males and tadpoles distribution. Groups of species distributed differentially through the hot and moist months, where typical species of beginning, middle, and end of the rainy season could be identified. A macro-spatial analysis of anuran distribution evidenced low similarity among different sampled phytophysiognomies. Actually, the low faunistic similarity is rather a consequence of the low efficiency of capture by pitfall traps with drift fences, resulting in low species richness in the phytophysiognomies studied. However, a high similarity on species composition was found only among the most preserved areas of MDSP, due to the presence of Rhinella ornata. This species was indicative of the most preserved area of the MDSP, while two other species from the Leiuperidae family (Eupemphix nattereri and Physalaemus cuvieri)... (Complete abstract click electronic access below)

Dans le cadre de l’analyse des crises financières au sein des pays émergents, de nombreux travaux sont venus expliquer l’occurrence de ce genre de phénomènes. Pourtant, des faits nouveaux se manifestent sans pour autant s’inscrire dans les recherches déjà proposées (Brésil, Corée du Sud et pays d’Europe centrale et orientale principalement). En référence à cette littérature, la thèse pose en retour la question de l’incidence de la contagion financière sur la dégradation des fondamentaux macroéconomiques et macro-financiers de pays émergents susceptibles d’être initialement considérés comme « robustes ». La réponse passe par la mise en évidence des principales composantes des crises financières pour en extraire les limites face à l’hypothèse soulevée. La description des stratégies de rattrapage économique, par l’intégration au marché financier international, est à l’origine des vulnérabilités potentielles dans les effets de contagion. La structure instable de l’endettement international, à l’aide de l’Hypothèse d’Instabilité Financière de Minsky (1974), va offrir les éléments théoriques nécessaires à la modélisation des faits empiriques. Les premières générations de crises de change viendront conceptualiser la fuite des capitaux en attribuant la responsabilité de la contraction de la liquidité au reste du monde. Dans la transition qu’ils opèrent actuellement en vue de leur adhésion à l’UEM, les PECO ne peuvent être considérés comme étant à l’abri de la survenance de crises financières, et ce même s’ils bénéficient des impacts stabilisateurs favorables liés à leur appartenance à l’UE. Mais disposent-ils alors des facteurs de robustesse macroéconomique et macro-financière s / As part of the analysis of financial crises in emerging countries, many studies have come to explain the occurrence of such phenomena. However, developments occur without enrolling in research already available (Brazil, South Korea and countries in Central and Eastern Europe mainly). In reference to this literature, the thesis in turn raises the question of the impact of financial contagion on the degradation of macro-economic fundamentals and emerging countries' financial might initially be regarded as "robust." The answer lies in the identification of key components of financial crises to extract the limits against the hypothesis raised. The description of the strategies of economic recovery, by the international financial market integration, is the source of potential vulnerabilities in the contagion. The unstable structure of international debt, with the financial instability hypothesis of Minsky (1974), will provide the theoretical elements necessary for modeling of empirical facts. The first generation of currency crises will conceptualize capital flight by assigning responsibility for the liquidity squeeze in the world. In the transition they currently operate with a view to joining EMU, the Central and Eastern Europe countries cannot be considered safe from the occurrence of financial crises, even if they have favorable impacts associated with stabilizers membership in the EU. But then they have robust macroeconomic factors and macro-financial enough to ward off the economic impact of any pressure by contagion? The empirical part of the thesis should answer the question through analytical and econometric modeling

L'obiettivo della tesi è lo sviluppo e nell'analisi di un modello macro-finanziario con aspetti reali e finanziari dell'economia, nell'ottica di ottenere un quadro comprensivo per l'analisi del rischio sistemico e delle instabilità. Il primo capitolo verte sulla costruzione di un modello ad agenti che si caratterizza per la presenza del mercato dei beni, del credito, del lavoro e interbancario. Il modello riproduce fluttuazioni endogene ed è in grado di replicare alcuni fatti stilizzati riguardanti i cicli economici e creditizi, mentre il mercato interbancario ha un ruolo importante dal punto di vista della stabilità e dell'efficienza. In particolare la regolazione prudenziale combinata con le aspettative adattive può esacerbare il comportamento precauzionale delle banche durante una recessione, inducendo a trattenere liquidità anche le banche solide. Inoltre la connettività del mercato interbancario ha un duplice effetto: da un lato favorisce l'accesso al credito nell'economia reale, dall'altro accresce l'accumulo di liquidità. Il secondo capitolo si concentra su un insieme di esperimenti condotti tramite il modello precedentemente sviluppato. Lo scopo è di confrontare tra loro politiche macro-prudenziali in cui le banche sono soggette a requisiti minimi di capitale derivati da misure di rischio sistemico. Nello specifico gli indicatori di rischio sistemico sono suddivisi in misure di mercato e di rete. Ogni categoria è ulteriormente scomposta in misure di vulnerabilità e misure di impatto. I risultati rivelano che le politiche costruite su indicatori di vulnerabilità sono migliori di quelle basate sull'impatto, dato che riducono i fallimenti da contagio senza peggiorare la performance macroeconomica. / The purpose of the thesis is to develop and analyse a macro-financial model with real and financial aspects of the economy to obtain a comprehensive framework for the analysis of systemic risk and instabilities. The first chapter concerns the construction of an agent-based-model, whose characteristic is the presence of goods, credit, labour and interbank markets. The model reproduces endogenous business cycles and it is able to replicate some stylized facts about business and credit cycles, while the interbank market has an important role for stability and efficiency. In particular prudential regulation, combined with adaptive expectations can exacerbate the precautionary behaviour of banks during a recession, inducing liquidity hoarding by sound banks. Furthermore connectivity of the interbank market has a twofold effect: on one side it supports credit to the real economy, on the other it increases liquidity hoarding. The second chapter is focused on a set of policy experiments performed performed on the model previously developed. The aim is to compare different macroprudential policies where banks are subject to minimum capital requirements derived from systemic risk measures. In detail systemic risk indicators are divided in market-based and network based measures. Each class is further decomposed in measures of vulnerability and measures of impact. The results reveal that policies based on vulnerability indicators perform better than those based on impact, reducing contagious defaults without worsening the macroeconomic performance.

Depuis une trentaine d’années, le développement durable s’est imposé comme un référentiel dans l’action, tant privée que publique. L’exigence qu’il pose de mettre en cohérence des normes globales avec des pratiques localisées, engage la question de la coopération territoriale. Ainsi, nous tentons de voir en quoi la mise en application de stratégies de développement durable par certaines collectivités territoriales de la région Nord – de Pas de Calais, permet un meilleur traitement du problème de l’articulation micro-macro des décisions. La mobilisation de la grille de lecture des « Économies de la Grandeur » permet de montrer que cette mise en cohérence résulte du partage de représentations sur le sens d’une notion dont les approches sont très diverses. À cet égard, l’existence d’une convention de développement durable apparaît comme le signe d’un traitement adapté de l’articulation micro-macro. À partir d’analyses des discours d’une trentaine d’acteurs locaux, nous avons dégagé trois principaux résultats. 1/. Il n’existe pas de grandeur morale de la durabilité, dotée d’une légitimité propre, capable de susciter l’adhésion des individus à une action collective en faveur du développement durable. 2/. La formation d’un cadre de représentations communes émerge de la pratique des acteurs. Cette convention pragmatique prend appui sur diverses critiques du compromis du service public français. Elle élargit ainsi les grandeurs industrielle (écoefficacité) et civique (solidarité territoriale, intergénérationnelle…), à partir d’éléments propre à la cité domestique (identité territoriale). 3/. Cette convention se trouve configurée dans une nouvelle gouvernance par projets qui assure l’existence d’espace ponctuels de coopération territoriale. / For the last thirty years, sustainable development has become a reference for action that private or public decision-makers cannot ignore. Bringing forward issues of territorial cooperation, this notion emphasizes the consistency between global norms and local practices. Therefore, we assume that the implementation of sustainable development strategies in the territorial communities of the Nord – Pas de Calais Region could improve the understanding of the micro-macro decisions articulation. Using the “Economies of Worth” framework, we show that micro-macro consistency of the decisions comes from cognitive representations that are shared by the communities. This seems uneasy to set-up given the large diversity of the approaches of sustainable development. The existence of a “convention”, in the French “Economics of Conventions” sense, would mean that the problem has been properly considered by the territorial actors. Three main conclusions can be drawn from their speeches analysis. 1/. Sustainable development does not rely on a moral worth that would have a legitimate foundation on its own, enabling individual commitment to sustainable development collective actions. 2/. The shaping of collective representations, shared by the actors, rises from their sustainable development practices. This pragmatic convention relies on various criticisms of the “compromise” of the French public service. Therefore, it widens the industrial worth (eco-efficiency) and the civic worth (territorial and intergenerational solidarity), using elements from the domestic polity. 3/. This convention is set-up in a governance of public actions based on sustainable development projects, ensuring the local existence of cooperation spaces.

Le sol est une des composantes essentielles au soutien du fonctionnement de l’écosystème. Il est lesupport de la production primaire, un habitat pour la diversité biologique et remplit de nombreux processus écologiques. Les activités anthropiques, et parmi elles, les pratiques agricoles intensives, ont conduit à des déséquilibres au sein du sol causant un fort déclin de leur biodiversité. En réponse à ces effets, de nouvelles pratiques agricoles ont été développées pour préserver les sols et les services écosystémiques qu’ils fournissent. Ces pratiques dites innovantes s’appuient principalement sur la réduction du travail du sol, une gestion intégrée des résidus de culture, l’installation d’un couvert végétal permanent ou encore l’introduction de légumineuses dans les rotations de culture. C’est dans ce contexte de mutation des pratiques agricoles que s’inscrit ce sujet de thèse qui vise à mieux comprendre les effets de l’adoption de ces gestions innovantes sur (i) la diversité des communautés de la macro- et de la mésofaune du sol et (ii) sur le fonctionnement du sol en termes de stockage ducarbone organique (source de nourriture de base), de structure du sol et de distribution de la taille des pores (milieu de vie). Au cours des différents chapitres de ce travail, nous avons mis en évidence trois actions liées à des pratiques agricoles innovantes combinant des approches expérimentales in et ex situ. L’objectif de la première action visait à étudier l’effet combiné de l’introduction de légumineuse (féverole) et de la réduction du travail du sol sur le compartiment endogé. Pour y répondre, nous avons développé une conception expérimentale empirique faite avec la combinaison des situations rencontrées dans les fermes. Nos résultats ont montré que l’interaction entre les deux pratiques innovantes n’a pas entrainé d'augmentation significative de la diversité de la faune du sol. Les fonctions microbiennes ainsi que la dynamique du carbone (C) et de l’azote (N) ne semblent pas non plus être affectées par ces pratiques. Il s’avère que les effets bénéfiques de ces pratiques innovantes ne peuvent être envisagés sans prendre en compte la manière dont elles sont mises en oeuvre à l’échelle des rotations culturales et des itinéraires techniques. Cela nous a permis de valoriser une seconde action dont l’objectif était de suivre dans les mêmes conditions pédoclimatiques et mêmes itinéraires techniques, l'effet à long terme (quatre ans) de cinq régimes de gestion différents sur les communautés de faune du sol. Les traitements comprenaient des combinaisons de différentes cultures (annuelles, vivaces), de différents taux de fertilisation azotée (ajout d'azote, azote réduit),incorporation ou élimination de résidus de culture et différentes intensités de labour (labour vs. travail superficiel). Les résultats ont montré que la réduction de l’intensité du travail du sol a favorisé la diversité des collemboles et ses groupes fonctionnels grâce à l’amélioration des conditions de l’habitat à travers l’augmentation de la biomasse microbienne de carbone (source trophique). Par ailleurs, les autres composantes de la gestion, soit la « réduction des apports d’azote » et la « restitution / exportation des résidus de culture», n’ont pas eu d’effet sur les collemboles (abondance et richesse), notamment sur ceux vivants dans le sol, qu'ils soient hémi ou euédaphiques. Toutefois, cette étude démontre que la dissemblance dans la composition des assemblages de collemboles augmente avec la différenciation temporelle des pratiques agricoles et le travail du sol est le premier facteur responsable de cette trajectoire. Cette assertion a donné lieu à une troisième action dont l’objectif était de suivre sur une saison de végétation la conversion de la perturbation mécanique résultant du travail du sol sur la résistance et résilience fonctionnelle des assemblages biotiques édaphiques. / Soil is one of the essential components supporting the functioning of the ecosystem. It is the support of primary production; an habitat for biodiversity, and it fulfills many ecological processes. Human activities, including intensive agricultural practices, have led to impaired the soil causing a sharp decline in their biodiversity. In response to these effects, new agricultural practices have been developed to preserve the soils and the ecosystem services they provide. These so-called innovative practices rely mainly on the reduction of tillage, integrated management of crop residues, the installation of permanent plant cover or the introduction of legumes into crop rotations. It is in this context of changes in agricultural practices that this thesis topic lays. This thesis aims to better understand the effects of the adoption of these innovative management practices on (i) the diversity of the macro and mesofauna communities soil and (ii) soil functioning in terms of organic carbon storage (basic food source), soil structure and pore size distribution (living environment). During the different chapters of this work, we highlighted three actions related to innovative agricultural practices combining in situ and ex situ experimental approaches. The aim of the first action was to study the combined effect of the introduction of legume (faba bean) and the reduction of tillage on the endogenous compartment. To answer this question, we developed an empirical experimental design made with the combination of situations encountered on farms. Our results showed that theinteraction between the two innovative practices did not result in a significant increase in the diversity of soil fauna. Microbial functions and the dynamics of carbon (C) and nitrogen (N) also do not seem to be affected by these practices. It turns out that the beneficial effects of these innovative practices cannot be considered without taking into account how they are implemented at the scale of crop rotations and technical itineraries. This allowed us to promote a second action whose objective was to follow, under the same pedoclimatic conditions and the same technical itineraries, the long-term effect (four years) of five different management regimes on the communities of soil fauna. Treatments included combinations of different crops, different rates of nitrogen fertilization, incorporation or removal of crop residues and different plowing intensities. The results showed that the reduction of tillage intensity favored the diversity of Collembola and its functional groups by improving habitatconditions through the increase of microbial carbon biomass (trophic source). In addition, the other components of management, namely the "reduction of nitrogen inputs" and the "restitution / export of crop residues", had no effect on springtails (abundance and wealth), in particular on those living in the soil, whether hemi or euedaphic. However, this study demonstrates that the dissimilarity in the composition of Collembola assemblages increases with the temporal differentiation of agricultural practices, and tillage was the main factor responsible for this trajectory.

Cette thèse propose différentes méthodes numériques pour simuler les plasmas ou les faisceaux de particules chargées à coût réduit. Le mouvement de particules chargées soumises à un champ électromagnétique est régi par l'équation de Vlasov, couplée aux équations de Maxwell ou de Poisson. Dans la première partie, une méthode multi-fluides est utilisée pour la résolution du système de Vlasov-Poisson 1D. Elle est basée sur la connaissance a priori de la forme prise par la fonction de distribution f. Ce type de méthodes est plutôt adapté aux systèmes restant proches de l'état d'équilibre. La deuxième partie propose de décomposer f en une partie d'équilibre et une perturbation. L'équilibre est résolu par une méthode fluide, la perturbation par une méthode cinétique plus précise. On construit un schéma préservant l'asymptotique pour le système de Vlasov-Poisson-BGK basé sur une telle décomposition. On étudie dans la troisième partie la méthode PIC en géométrie 2D axisymétrique. Un travail basé sur l'analyse isogéométrique est présenté ainsi qu'un code PIC - Galerkin Discontinu parallélisé sur carte graphique. / This thesis presents different numerical methods for the simulation of plasmas or charged particles beams with reduced cost. Movement of charged particles in an electromagnetic field is given by the Vlasov equation, coupled to the Maxwell equations for the electromagnetic field, or to the Poisson equation. In the first part, a multi-fluid method is used for solving the 1D Vlasov-Poisson system. It is based on the a priori knowledge of the shape of f. This kind of methods is rather adapted to systems staying close to the equilibrium. The second part presents the decomposition of f between an equilibrium part and a perturbation. The equilibrium part is solved by a fluid method whereas we use a kinetic method for the perturbation. We construct an asymptotic preserving scheme for the Vlasov-Poisson-BGK system using such a decomposition. The third part deals with the PIC method in 2D axisymmetric geometry. A work based on isogeometric analysis is presented, and then a PIC - Discontinuous Galerkin program computed on graphic card.

Há pouca informação sobre o agronegócio sustentável para biocombustíveis elaborados a partir de oleaginosas florestais perenes, num contexto de sóciobiodiversidade. Na presente pesquisa, foi proposto e aplicado um framework para analisar a emergência, evolução e consolidação de uma filière do biodiesel a partir da macaúba, uma oleaginosa florestal perene, orientada pelo desenvolvimento sustentável. Para isso, utilizou-se a combinação de três abordagens e instrumentos, resumidos a seguir: O primeiro é o metaframework transdisciplinar de Munasinghe (2002), o Sustainomics. O segundo, constituído pela análise de filière, uma abordagem francesa, e suas diretrizes mesoanalíticas: tecnologias, estratégia e relações (MONTIGAUD, 1991). O terceiro, no âmbito da Economia Evolutiva, utilizou-se o framework Micro-Meso-Macro (DOPFER, FOSTER e POTTS, 2004). Essas abordagens e alguns de seus instrumentos foram ajustados entre si, por meio de suas dimensões e elementos integrativos, para proposição de um novo framework na presente pesquisa, intitulado “Cadeia Oleaginosa Florestal Perene Micro- Meso-Macro Transdisciplinar-Sustainomics”, concebido tanto para a identificação como a recomendação de prioridades presentes e futuras para a cadeia estudada. A presente pesquisa é exploratória e qualitativa, na qual foram coletados dados primários e secundários. Na coleta de dados primários, foram feitas entrevistas, registradas em vídeo. Dos 7 elos identificados na filière da macaúba, o estudo de caso abordou os sistemas de produção, adotados e prospectados, no Elo Agrícola e na Agroindústria, no período entre 2004 a 2009, no locus geográfico do município de Montes Claros/MG. Os resultados foram interpretados com base nos instrumentos Matriz de Impacto da Ação, Análise diagnóstica sistêmica da filière e em duas técnicas da Economia Evolutiva: a Trajetória Micro Como um Domínio Analítico e a Análise da Trajetória Meso Genérica. Identificou-se em primeiro lugar, que das 6 empresas que atuam diretamente na filière emergente, no Brasil, nenhuma explora exclusivamente biodiesel de macaúba. Em segundo, existe a possibilidade de um jogo do tipo ganha-ganha no caso analisado, possibilitando simultaneamente “a melhoria da vida das pessoas pobres e o combate ao problema das mudanças climáticas” (MUNASINGHE, 2002). Na analise dos resultados são apontados, a recomendação de substituições progressivas: 1) Do diesel fóssil por biocombustíveis, que tenham ciclo de vida, de fato, renovável; 2) Das matérias-primas de ciclo anual, com baixos rendimentos em biocombustíveis, provenientes de monocultivos, por policultivos de culturas perenes, da biodiversidade dos biomas, com foco na macaúba para o Cerrado; 3) Da monocultura da soja pelas matérias-primas para biocombustíveis oriundas dos recursos florestais naturais não madeiráveis, organizada em sistema de produção agroflorestas sucessionais, com inovação pelo uso nas áreas de Reservas Legais, sustentáveis na forma de campos de produção. 4) Da entropia do desmatamento, pela sintropia; 5) Do biodiesel pelo uso direto – SVO: desatrelar o processo tecnológico agroindustrial equivocado de transesterificação do óleo vegetal para retirada da glicerina do óleo; 6) Dos motores de ciclo diesel não adiabáticos, produzidos e utilizados no Brasil, por novas tecnologias disponíveis: operar com temperaturas mais altas para queimar, como biocombustível, também a glicerina, evitar a desnecessária geração de resíduos. Por fim, o framework de análise para culturas perenes oleaginosas sustentáveis (Cadeia Oleaginosa Florestal Perene Micro-Meso-Macro Transdisciplinar-Sustainomics) utilizado neste estudo de caso, pode ser aplicado para outras culturas similares, com o objetivo de evitar catástrofes bruscas, sem demora, eliminando atividades que ameacem superar o limiar de segurança e capacidade de carga dos ecossistemas da Terra, por meio do aumento de sua resiliência. / There is little information about the sustainable agribusiness for biofuels made from perennial oil forest of sociobiodiversity context. This research aimed to propose a framework and analyze the emergence, evolution and consolidation of a biodiesel filière from Macaúba, guided by sustainable development. For this, it proposes a new model by combinning tree approaches and instruments from the models sumarized as follow: The first tool model is the practical method of Munasinghe (2002): a transdisciplinary metaframework, the Sustainomics, that has evaluative techniques of unsustainable activities. The second is the Filière Method, composed by the following mesoanalitics guidelines: technology, strategy and relationships (MONTIGAUD, 1991). The third envolves levels of Evolutionary Economics, derivatives from the Framework Micro-Meso-Macro (DOPFER FOSTER and POTTS, 2004). These approaches and some instruments used from the models, fit together the dimensions and elements of integration, to propose the mentioned new model entitled as a neologism “Cadeia Oleaginosa Florestal Perene Micro-Meso-Macro Transdisciplinar-Sustainomics”, designed to identify and to recommend urgent priorities in the present and in the future, to the studied chain. This research is exploratory, qualitative, within collected primary and secondary data. Primary data was interviews with video recorded. From the seven rings of chain (Macaúba filière) that were identified, the study case addresses the production systems, some adopted and some prospected, in Agricultural and Agroindustry rings, between the period from 2004 to 2009, the geographical locus of the municipality of Montes Claros/MG. The results were analyzed based on the instruments, as follow: Action Impact Matrix, Diagnostic analysis of systemic filière, and two Evolutionary Economics techniques: Trajectory Micro as an Analytical Domain and Analysis of the Meso Generic Trajectory. It was identified, first, that: the six companies operating directly in emerging filière, none operates exclusively Macaw Palm’s biodiesel. The Second consideration refers that it is possible a win-win game, for the analysed case, making possible coexistence: “improving the lives of poor people and addressing the issue of climate change” (MUNASINGHE, 2002). The results pointed the recomendations of progressive replacement of: 1) The fossil diesel through biofuels, which have life cycle, in fact, renewed; 2) The raw materials of the annual cycle, with low yields of biofuels from monocultures, through polycultures of perennial crops, from biodiversity biomes, focusing on Macaw Palm, for Savannah. 3) the monoculture of soybeans for biofuels, through raw-material derived from Non-Timber Natural Forest resources, organized in successional agroforestry system of production, with innovation for use inthe areas of Legal Reserves, as sustainable production fields. 4) The entropy of deforestation, through the Syntropy; 5) From biodiesel through the direct use - SVO: unleash the technological process of wrong agroindustrial transesterification of vegetable oil to remove the glycerin from the oil; 6) From diesel cicle engines non-adiabatic, produced and used in Brazil through new available technologies: to operate at higher temperatures to burn, as biofuel, as well as glycerin, to avoid unnecessary waste generation. Summing up, the analysis model for perennial crops, oilseeds sustainable (Cadeia Oleaginosa Florestal Perene Micro-Meso-Macro Transdisciplinar-Sustainomics), used in this case study can be applied to other similar cultures, in order to prevent sudden disasters, without delay, eliminating activities that threaten to exceed the safety threshold and carrying capacity of Earth's ecosystems, by increasing its resilience.