The internal structure of ice sheets reflects the history of flow and deformation experienced by the ice mass. Flow and deformation are controlled by processes occurring within the ice mass and at its boundaries, including surface accumulation or ablation, ice rheology, basal topography, basal sliding, and basal melting or freezing. The internal structure and basal environment of ice sheets is studied with ice-penetrating radar. Recently, radar observations in Greenland and Antarctica have imaged large englacial structures rising from near the bed that deform the overlying stratigraphy into anticlines, synclines, and overturned folds. The mechanisms that may produce these structures include basal freeze-on, travelling slippery patches at the ice base, and rheological contrasts within the ice column. In this thesis, I explore the setting and mechanisms that produce large basal stratigraphic structures inside ice sheets. First, I use radar data to map subglacial hydrologic networks that deliver meltwater uphill towards freeze-on structures in East Antarctica. Next, I use a thermomechanical flowline model to demonstrate that trains of alternating slippery and sticky patches can form underneath ice sheets and travel downstream over time. The disturbances to the ice flow field produced by these travelling patches produce stratigraphic folds resembling the observations. I then examine the overturned folds produced by a single travelling sticky patch using a kinematic flowline model. This model is used to interpret stratigraphic measurements in terms of the dynamic properties of basal slip. Finally, I use a simple local one-dimensional model to estimate the thickness of basal freeze-on that can be produced based on the supply of available meltwater, the thermal boundary conditions, ice sheet geometry, and the ice flow regime.

Centrada numa perspectiva discursiva - a da análise do discurso - esta pesquisa trabalha tendo como foco teórico a constituição/identidade das formações discursivas e relações interdiscursivas de caráter polêmico. Além disso, indagações como as dimensões interdisciplinares da análise do discurso e a concepção de análise do discurso político ficaram também contempladas na trajetória. Para efeito de averiguação da conformação do foco teórico, escolhemos como corpus a diversidade dos discursos escritos que se confrontaram, durante o processo de privatização da Companhia Vale do Rio Doce - CVRD - maior companhia do mundo em atividade de extração mineral. Esse processo não se deu de forma pacífica e consensual, mas sob exaustivos debates de confronto entre governo e sociedade civil. Esse confronto levou a um questionamento: o fato de o processo ter se dado sob exaustivos debates, configurou-lhe uma aparência democrática, no entanto, o discurso \"vencedor\" é aquele identificado com o discurso governamental o qual propõe e efetiva a privatização. Se houve estratégias de condução do processo, como está caracterizado o perfil do discurso \"vencedor\": persuasivo, convincente ou simplesmente hegemônico? Esse questionamento, em linhas gerais, levou aos seguintes objetivos: confrontar os argumentos verificando a força de um em relação ao outro; verificar o mecanismo de refutação e como as identidades e as imagens discursivas são construídas. A questão subjacente é buscar compreender, através de formas de produção de sentidos como os fenômenos políticos se instalam ou se constituem discursivamente numa confluência de espaços e poderes nem sempre passíveis de clareza e visibilidade. / Centred around a discursive perspective - the discourse analysis - this research has as theoretical focus the constitution/identity of the discursive formations and controversial interdiscursiviness relations. Furthermore, inquiries such as the discourse analysis interdisciplinary dimensions and the conception of the political discourse analysis were also observed. In order to verify the theoretical focus , we have chosen as corpus the written discourses diversities that confronted during Companhia Vale do Rio Doce - CVRD privatization process. CVRD is the largest mining company in the world. Its privatization process did not happen in a peaceful and consensual way, but with exhaustive confrontational debates between government and civil society. This confront led to a question: as the process has occurred with exhaustive debates, it happened to have a democratic appearance, nevertheless, the \"victorious\" discourse is the one identified with the governmental discourse, that proposes and effects the privatization. If there were strategies of how to conduct the process, how is the appearance of the persuasive \"victorious\" discourse characterized, convincing or simply hegemonic? On the whole, this question, has led to the following objectives: confront the arguments verifying the strength of one in relation to the other; verify the refutation mechanism and how the identities and discursive images are built. The underlying question is to understand, how the political phenomena are settled or if they are established discursively in a space and power confluence not always liable to clarity and visibility.

Made available in DSpace on 2017-07-10T17:30:45Z (GMT). No. of bitstreams: 1 Wanessa S P Dal Berti.pdf: 7008811 bytes, checksum: 38f5735759abf5feff9301bbc4b7810d (MD5) Previous issue date: 2015-12-08 / The research presents the characterization of surface formations in the sector covering the geomorphic surfaces IV and III in the Araucária Plateau, including transitions to surfaces II and V, in order identify the stage of materials evolution in representative profiles of each geomorphic surface. For this we used the lifting of macro morphology characteristics of surface, and laboratory analyzes of particle size, macronutrients, sulfuric attack and clays diffractogram of X-rays. The representative profile of the surface IV, developed on basaltic substrate, in surface with elevation between 1000 and 1100m, has over 4 meters thichness and solum more than 230cm, corresponding to Nitossolo Bruno Distroférrico Aluminico. It s mineral matter consists of quartz, anatase, ilmenite, hematite, goethite, gibbsite, kaolinite and possible presence of vermiculite. Between the geomorphic surfaces IV and III, the change of profile is developed on rhyolite, with soil 220cm thick whose morphological characteristics individualize Oxisol Distrofic, aluminum character. The Horizon B mineral matter consists of quartz, anatase, gibbsite, kaolinite and possible presence of VHE (vermiculite hydroxy between layers). The morphological characteristics of this profile indicate evolved weathering stage, although the horizon B has only 55cm. On the surface III, the profile described amendment corresponds to Oxisol Distroferric aluminum, whose mineralogy in the sand and silt fractions are made up of quartz, tridymite, cristobalite, spinel, magnetite, ilmenite, hematite, goethite and it s polimorfo, the lepidocrocite. In the clay fraction occur goethite, hematite, brookita, diaspore, boehmite, kaolinite and diquita, although vermiculite Al-OH between layers (VHE), besides the boehmita and mineral zeolites group. In the transition area between the geomorpfic surfaces V and IV, the changing profile showed 550cm thick, of which 370cm correspond to soil. Presents very weathered material, the type Oxisol Distroferric aluminium, the characteristics of sulfuric attack indicate that volumes appear to have no evolutionary relation with each other, indicating that is not changing material developed in situ. The minerals in the sand and silt fraction are cristobalite, tridymite, magnetite, ilmenite, hematite, goethite and apinel. In the clay fraction occurring minerals similar to those recorded in the B horizon of the representative profile of the surface III. In short, the weathering profile identified in geomorphic surfaces studies (IV, III and transitions) have very similar morphological characteristics indicating overall, high change stage. The four representative profiles analyzed there fall into the class of Oxisol, varying only distrophic,for distroferric, and is presented in Nitossolo Bruno Distroferric aluminium class. Of these profiles, three have development features from indigenous parent material (P1, P4 and P11), while the P13 profile shows parental relation with allochthonous material. / A pesquisa apresenta a caracterização das formações superficiais em setor que abrange as superfícies geomórficas IV e III no Planalto das Araucárias, incluindo as transições para superfícies II e V, buscando identificar o estágio de evolução dos materiais em perfis representativos de cada superfície geomórfica. Para tal utilizou-se do levantamento das características macromorfológicas da cobertura superficial em campo, bem como de análises laboratoriais de granulometria, macronutrientes, ataque sulfurico e difratogrametria de raios-X de argilas. O perfil representativo da superfície IV, desenvolvido sobre substrato basáltico, em superfície com elevação entre 1000 e 1100m, apresenta mais de 4 metros de espessura e solum com mais de 230 cm, correspondendo a Nitossolo Bruno Distroférrico Alumínico. Sua matéria mineral é constituída por quartzo, anatásio, ilmenita, hematita, goethita, gibbsita, caulinita e possível presença de vermiculita. Entre as superfícies geomórficas IV e III, o perfil de alteração desenvolve-se sobre riolito, apresentando solum com 220 cm de espessura cujas características morfológicas individualizam Latossolo Bruno Distrófico, caráter alumínico. A matéria mineral do horizonte B é constituída por quartzo, anatásio, gibbsita, caulinita e possível presença de VHE (vermiculita hidroxi entre camadas). As características morfológicas desse perfil indicam estágio de intemperismo evoluído, apesar do horizonte B apresentar apenas 55 cm. Na superfície III, o perfil de alteração descrito corresponde a Latossolo Bruno Distroférrico Alumínico, cuja mineralogia nas frações areia e silte constituem-se de quartzo, tridimita, cristobalita, espinélio, magnetita-magenita, ilmenita, hematita, goetita e seu polimorfo, a lepidocrocita. Na fração argila ocorrem goetita, hematita, brookita, diásporo, boehmita, caulinita e diquita, bem como vermiculita Al-OH entre camadas (VHE), além da boehmita e mineral do grupo da zeólitas. Na área de transição entre as superfícies geomórficas V e IV, o perfil de alteração mostrou 550 cm de espessura, dos quais 370 cm correspondem a solum. Apresenta material muito intemperizado, do tipo Latossolo Bruno Distroférrico Alumínico, cujas características do ataque sulfúrico indicam que os volumes não aparentam ter relação evolutiva entre si, indicando que não se trata de material de alteração desenvolvido in situ. Os minerais presentes na fração areia e silte são cristobalita, tridimita, magnetita, ilmenita, hematita, goetita e espinélio. Na fração argila ocorrem minerais similares aos registrados no horizonte B do perfil representativo da superfície III. Em suma, os perfis de intemperismo identificados nas superfícies geomorfológicas estudadas (IV, III e transições) apresentam características morfológicas bastante similares indicando, no geral, estágio de alteração elevado. Dos quatro perfis representativos analisados, três se enquadram na classe dos Latossolos, com variação apenas de distrófico para distroférrico, e um apresenta-se na classe Nitossolo Bruno Distroférrico Alumínico. Desse total de perfis, três apresentam características de desenvolvimento a partir de material parental autóctone (P1, P4 e P11), enquanto o perfil P13 mostra relação com material parental alóctone.

Made available in DSpace on 2017-05-12T14:42:17Z (GMT). No. of bitstreams: 1 Wanessa S P Dal Berti.pdf: 7008811 bytes, checksum: 38f5735759abf5feff9301bbc4b7810d (MD5) Previous issue date: 2015-12-08 / The research presents the characterization of surface formations in the sector covering the geomorphic surfaces IV and III in the Araucária Plateau, including transitions to surfaces II and V, in order identify the stage of materials evolution in representative profiles of each geomorphic surface. For this we used the lifting of macro morphology characteristics of surface, and laboratory analyzes of particle size, macronutrients, sulfuric attack and clays diffractogram of X-rays. The representative profile of the surface IV, developed on basaltic substrate, in surface with elevation between 1000 and 1100m, has over 4 meters thichness and solum more than 230cm, corresponding to Nitossolo Bruno Distroférrico Aluminico. It s mineral matter consists of quartz, anatase, ilmenite, hematite, goethite, gibbsite, kaolinite and possible presence of vermiculite. Between the geomorphic surfaces IV and III, the change of profile is developed on rhyolite, with soil 220cm thick whose morphological characteristics individualize Oxisol Distrofic, aluminum character. The Horizon B mineral matter consists of quartz, anatase, gibbsite, kaolinite and possible presence of VHE (vermiculite hydroxy between layers). The morphological characteristics of this profile indicate evolved weathering stage, although the horizon B has only 55cm. On the surface III, the profile described amendment corresponds to Oxisol Distroferric aluminum, whose mineralogy in the sand and silt fractions are made up of quartz, tridymite, cristobalite, spinel, magnetite, ilmenite, hematite, goethite and it s polimorfo, the lepidocrocite. In the clay fraction occur goethite, hematite, brookita, diaspore, boehmite, kaolinite and diquita, although vermiculite Al-OH between layers (VHE), besides the boehmita and mineral zeolites group. In the transition area between the geomorpfic surfaces V and IV, the changing profile showed 550cm thick, of which 370cm correspond to soil. Presents very weathered material, the type Oxisol Distroferric aluminium, the characteristics of sulfuric attack indicate that volumes appear to have no evolutionary relation with each other, indicating that is not changing material developed in situ. The minerals in the sand and silt fraction are cristobalite, tridymite, magnetite, ilmenite, hematite, goethite and apinel. In the clay fraction occurring minerals similar to those recorded in the B horizon of the representative profile of the surface III. In short, the weathering profile identified in geomorphic surfaces studies (IV, III and transitions) have very similar morphological characteristics indicating overall, high change stage. The four representative profiles analyzed there fall into the class of Oxisol, varying only distrophic,for distroferric, and is presented in Nitossolo Bruno Distroferric aluminium class. Of these profiles, three have development features from indigenous parent material (P1, P4 and P11), while the P13 profile shows parental relation with allochthonous material. / A pesquisa apresenta a caracterização das formações superficiais em setor que abrange as superfícies geomórficas IV e III no Planalto das Araucárias, incluindo as transições para superfícies II e V, buscando identificar o estágio de evolução dos materiais em perfis representativos de cada superfície geomórfica. Para tal utilizou-se do levantamento das características macromorfológicas da cobertura superficial em campo, bem como de análises laboratoriais de granulometria, macronutrientes, ataque sulfurico e difratogrametria de raios-X de argilas. O perfil representativo da superfície IV, desenvolvido sobre substrato basáltico, em superfície com elevação entre 1000 e 1100m, apresenta mais de 4 metros de espessura e solum com mais de 230 cm, correspondendo a Nitossolo Bruno Distroférrico Alumínico. Sua matéria mineral é constituída por quartzo, anatásio, ilmenita, hematita, goethita, gibbsita, caulinita e possível presença de vermiculita. Entre as superfícies geomórficas IV e III, o perfil de alteração desenvolve-se sobre riolito, apresentando solum com 220 cm de espessura cujas características morfológicas individualizam Latossolo Bruno Distrófico, caráter alumínico. A matéria mineral do horizonte B é constituída por quartzo, anatásio, gibbsita, caulinita e possível presença de VHE (vermiculita hidroxi entre camadas). As características morfológicas desse perfil indicam estágio de intemperismo evoluído, apesar do horizonte B apresentar apenas 55 cm. Na superfície III, o perfil de alteração descrito corresponde a Latossolo Bruno Distroférrico Alumínico, cuja mineralogia nas frações areia e silte constituem-se de quartzo, tridimita, cristobalita, espinélio, magnetita-magenita, ilmenita, hematita, goetita e seu polimorfo, a lepidocrocita. Na fração argila ocorrem goetita, hematita, brookita, diásporo, boehmita, caulinita e diquita, bem como vermiculita Al-OH entre camadas (VHE), além da boehmita e mineral do grupo da zeólitas. Na área de transição entre as superfícies geomórficas V e IV, o perfil de alteração mostrou 550 cm de espessura, dos quais 370 cm correspondem a solum. Apresenta material muito intemperizado, do tipo Latossolo Bruno Distroférrico Alumínico, cujas características do ataque sulfúrico indicam que os volumes não aparentam ter relação evolutiva entre si, indicando que não se trata de material de alteração desenvolvido in situ. Os minerais presentes na fração areia e silte são cristobalita, tridimita, magnetita, ilmenita, hematita, goetita e espinélio. Na fração argila ocorrem minerais similares aos registrados no horizonte B do perfil representativo da superfície III. Em suma, os perfis de intemperismo identificados nas superfícies geomorfológicas estudadas (IV, III e transições) apresentam características morfológicas bastante similares indicando, no geral, estágio de alteração elevado. Dos quatro perfis representativos analisados, três se enquadram na classe dos Latossolos, com variação apenas de distrófico para distroférrico, e um apresenta-se na classe Nitossolo Bruno Distroférrico Alumínico. Desse total de perfis, três apresentam características de desenvolvimento a partir de material parental autóctone (P1, P4 e P11), enquanto o perfil P13 mostra relação com material parental alóctone.

Cette recherche impliquée et impliquante nous a permis d’aborder « Les conceptions de l’animation socioculturelle dans les formations à l’animation de niveau III, Bac +2, à travers des formations proposées par des universités et des organismes de formation ». C’est à travers les différents contextes de formation, les valeurs défendues dans le métier d’animateur et de coordinateur, ainsi que les rapports théories et pratiques, que nous avons pu analyser le point de vue des étudiants et stagiaires avant la formation, et après la formation suivie.Nous avons pu comparer les décalages existants entre les curriculums formels, réels et cachés de ces formations, mais aussi établir des nuances dans les conceptions de l’animation socioculturelle à travers le macrosociologique et le microsociologique. / This implied research and impliquante allowed us to approach «The conceptions of the sociocultural animation in the trainings in the level animation III, Bac + 2, through trainings proposed by universities and bodies of training”.It is through the various contexts of training, the values defended in the profession by presenter and by coordinator, as well as reports theories and practices, that we were able to analyze the point of view of the students and the trainees before the training, and after the followed training.We were able to compare the existing gaps between curricula formal, real and hidden from these trainings, but also to establish nuances in the conceptions of the sociocultural animation through the macrosociological and the microsociological..

The goal of this research was to quantify the degradation experienced by a polymer electrolyte fuel cell after storage at subzero temperatures ranging from 0 to -40°C. The performance loss was determined by comparing the polarization and other applicable power curves before and after the subzero storage cycle. The causes of this performance degradation were investigated by the use of Scanning Electron Microscope, Energy Dispersive x-ray Spectroscopy, and porosity scanning technologies. It was found that there are two distinct types of degradation experienced by the membrane. The first type was identified as a variance of the actual voltage - current relationship of the cell. The membrane experienced a 2 - 15% power reduction depending on the load applied to the cell. This mode of degradation only pertained to the initial freeze/thaw cycle and was not observed after any number of subsequent cycles. The cause of this type of degradation has been hypothesized to be related to the delamination of the proton exchange, gas diffusion, and micro porous layers. The second type of degradation was only observed during the subsequent cycles, and mainly affected the high power regions of the operating range. A 5% reduction in current density and power output was observed as a result of further freeze/thaw cycles. Mass transport limitations may have been caused by the destruction of the meso-porous gas diffusion and micro-porous layers. The pore size, volume, and membrane surface area were quantified using a B.E.T. porosity scanner. The results showed that the pore diameter of the catalyst and proton exchange layer did not increase significantly. The porosity scanner did indicate that a pore volume increased by a factor of ten and was confirmed by the surface area measurements of the membrane. The S.E.M. investigations allowed visual inspection of the membrane's structural integrity. Physical separation of the catalyst and gas diffusion layers was observed in the experimental sample, while a more homogeneous assembly was seen in the control sample.

No description available.

L'étude détaillée de la cuvette du Lac de Paladru , des hautes vallées de la Fure et de l'Ainan est entreprise sous l'angle géophysique, géomorphologique et hydrogéologique.

La premlere partie de ce travail est consacrée à l'étude régionale de l' ensemble des formations cantaliennes au niveau de la cuvette de Murat et de la vallée de la Chevade . La deuxième partie, entreprise à la suite des travaux d'A. de GOER sur la planèze de Saint-Flour , consiste en une étude purement pétrologique des basaltes planéziens et miocènes de ce secteur. L'étude générale de la région de Murat va nous permettre dans un premier temps de replacer dans leur cadre structural les principaux épisodes basaltiques de la planèze de Saint - Flour et de ses marges.

Cette thèse concerne le contrôle coopératif de systèmes multi-agents. Ce sujet a été largement étudié dans la littérature récente en raison de son grand nombre d'applications. Cette thèse propose des nouvelles conceptions de stratégies de contrôle collaboratif afin de réaliser une mission d'exploration sous-marine. En particulier, l'objectif final est de diriger une flotte de véhicules autonomes sous-marins, équipés de capteurs appropriés, jusqu'à l'emplacement d'une source de température, de polluants ou d'eau douce. Dans cette situation, il est pertinent de considérer les contraintes de communication entre véhicules qui sont décrites au moyen d'un graphe de communication. Les premières contributions traitent du développement des lois de commande d'une formation qui stabilisent la flotte vers des formations variant dans le temps, et qui, de plus, distribuent uniformément les véhicules le long de la formation. Enfin, le problème de recherche d'une source est abordé par l'interprétation de la flottille de véhicules comme un réseau de capteurs mobiles. En particulier, il est démontré que les mesures recueillies par la flotte de véhicules permettent d'estimer le gradient de concentration de la quantité d'intérêt. En suivant cette idée, un algorithme distribué basé sur des algorithmes de consensus est proposé pour estimer la direction du gradient d'une distribution de signal.