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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.
141

Detailed Mapping of Lava Flows in Syrtis Major Planum, Mars

Demchuk, Robert W. 26 May 2021 (has links)
No description available.
142

La posición política como factor de definición del criterio informativo periodístico. Análisis comparativo de los diarios La República y La Razón en el tratamiento de la figura de Keiko Fujimori y su vínculo con el caso Lava Jato (2018-2020) / The political position as a defining factor of the journalistic information criterion. Comparative analysis of the newspapers La República and La Razón in the treatment of the figure of Keiko Fujimori and her enlace with the Lava Jato case

Poicon Diez, Alvaro Israel 23 December 2020 (has links)
La investigación tiene como objetivo central estudiar como los criterios de tratamiento informativo relacionados a hechos políticos que se ven afectados o alterados por la posición política de un diario. Para ello se ha elegido un caso específico: la relación entre Keiko Fujimori, excandidata presidencial y lideresa de Fuerza Popular, y el caso Lava Jato. Se realizará un estudio de tres hitos importantes de este caso los cuales son la detención preliminar a Keiko, los cambios que se realizaron en el Ministerio Público y la apelación de la prisión preventiva a Keiko. Se hará un análisis comparativo cualitativo de las notas emitidas por La República y La Razón para entender este fenómeno de la comunicación. / The main objective of the research is to study the information treatment criteria related to political events that are affected or altered by the political position of a newspaper. For this, a specific case has been chosen: the relationship between Keiko Fujimori, former presidential candidate and leader of Fuerza Popular, and the Lava Jato case. A study of three important milestones of this case will be carried out, which are the preliminary arrest of Keiko, the changes that were made in the Public Ministry and the appeal of the preventive detention to Keiko. A qualitative comparative analysis will be made of the notes issued by La República and La Razón to understand this phenomenon of communication. / Trabajo de investigación
143

Structural and volcanic evolution of the Glass Buttes area, High Lava Plains, Oregon

Boschmann, Darrick E. 29 November 2012 (has links)
The Glass Buttes volcanic complex is a cluster of bimodal (basalt-rhyolite), Miocene to Pleistocene age lava flows and domes located in Oregon's High Lava Plains province, a broad region of Cenozoic bimodal volcanism in south-central Oregon. The High Lava Plains is deformed by northwest-striking faults of the Brothers Fault Zone, a diffuse, ~N40°W trending zone of en echelon faults cutting ~250 km obliquely across the High Lava Plains. Individual fault segments within the Brothers Fault Zone are typically <20 km long, strike ~N40°W, have apparent normal separation with 10-100 m throw. A smaller population of ~5-10 km long faults striking ~N30°E exhibits mutually crosscutting relationships with the dominant northwest striking faults. Basaltic volcanic rocks in the Glass Buttes area erupted during the late Miocene and Pleistocene. The oldest and youngest lavas are 6.49±0.03 Ma and 1.39±0.18 Ma, respectively, based on ⁴⁰Ar/³⁹Ar ages of five basaltic units. Numerous small mafic vents both within and around the margins of the main silicic dome complex are commonly localized along northwest-striking faults of the Brothers Fault Zone. These vents erupted a diverse suite of basalt to basaltic andesite lava flows that are here differentiated into 15 stratigraphic units based on hand sample texture and mineralogy as well as major and trace element geochemistry. The structural fabric of the Glass Buttes area is dominated by small displacement, discontinuous, en echelon, northwest-striking fault scarps that result from normal to slightly oblique displacements and are commonly linked by relay ramps. Northwest alignment of basaltic and rhyolitic vents, paleotopography, and cross-cutting relationships suggest these faults have been active since at least 6.49±0.03 Ma, the age of the rhyolite lavas in the eastern Glass Buttes are. Faults displace Quaternary sedimentary deposits indicating these structures continue to be active into the Quaternary. Long-term extension rates across northwest-striking faults calculated from 2-5 km long cross section restorations range from 0.004 – 0.02 mm/yr with an average of 0.12 mm/yr. A subordinate population of discontinuous northeast-striking faults form scarps and exhibit mutually cross-cutting relationships with the dominant northwest-striking population. Cross-cutting relationships indicate faulting on northeast-striking faults ceased sometime between 4.70±0.27 Ma and 1.39±0.18 Ma. Gravity data at Glass Buttes reveals prominent northwest- and northeast-trending gravity gradients that closely parallel the strikes of surface faults. These are interpreted as large, deep-seated, normal faults that express themselves in the young basalts at the surface as the discontinuous, en echelon fault segments seen throughout the study area and BFZ in general. Elevated geothermal gradients are localized along these deep-seated structures at two locations: (1) where northwest- and northeast-striking faults intersect,(2) along a very prominent northwest-striking active normal fault bounding the southwest flank of Glass Butte. High average heat flow and elevated average geothermal gradients across the High Lava Plains, and the presence of hydrothermal alteration motivated geothermal resource exploration at Glass Buttes. Temperature gradient drilling by Phillips Petroleum and others between 1977-1981 to depths of up to 600 m defined a local geothermal anomaly underlying the Glass Buttes volcanic complex with a maximum gradient of 224 °C/km. Stratigraphic constraints indicate that near-surface hydrothermal alteration associated with mercury ores ceased before 4.70±0.27 Ma, and is likely associated with the 6.49±0.03 Ma rhyolite eruptions in the eastern part of Glass Buttes. The modern thermal anomaly is not directly related to the pre-4.70±0.27 Ma hydrothermal system; rather it is likely a result of deep fluid circulation along major extensional faults in the area. / Graduation date: 2013 / Includes accompanying DVD with digital data supplement (8 GB).
144

Governança, gestão de riscos e conformidade: Petrobras e Eletrobras, antes e depois da Operação Lava Jato

Silva, Wilson Cedraz da 31 October 2016 (has links)
Submitted by Biblioteca de Adminsitração (bibadm@ufba.br) on 2017-07-25T13:29:18Z No. of bitstreams: 1 Wilson Cedraz da Silva.pdf: 3054125 bytes, checksum: 19e4d7597d3f7a910644c6b4f313b9ec (MD5) / Approved for entry into archive by Maria Angela Dortas (dortas@ufba.br) on 2017-07-25T13:51:46Z (GMT) No. of bitstreams: 1 Wilson Cedraz da Silva.pdf: 3054125 bytes, checksum: 19e4d7597d3f7a910644c6b4f313b9ec (MD5) / Made available in DSpace on 2017-07-25T13:51:46Z (GMT). No. of bitstreams: 1 Wilson Cedraz da Silva.pdf: 3054125 bytes, checksum: 19e4d7597d3f7a910644c6b4f313b9ec (MD5) / O objetivo desta dissertação é analisar os sistemas de governança corporativa, gestão de riscos e conformidade da Petrobras e da Eletrobras, antes e depois da Operação Lava Jato, e verificar se foram realizadas as mudanças adequadas para a remediação das deficiências que levaram aos desvios de recursos. A relevância do trabalho está, principalmente, na análise das medidas que foram tomadas pelas empresas, diante das evidências de que um complexo esquema de corrupção vinha realizando grandes desvios de recursos, nestas que são as maiores estatais brasileiras, gozavam de boa reputação e tinham seus sistemas de controles certificados nacional e internacionalmente. Através de uma pesquisa documental e de outras fontes, as ações das empresas foram analisadas, com suas respectivas legislações sobre contratações, considerando os desdobramentos da Operação Lava Jato. A análise de conteúdo foi utilizada para avaliar as remediações das deficiências nos controles internos e as alterações na governança corporativa, gestão de riscos e conformidade, comunicados pelas empresas através de seus Formulários de Referência. Finalmente, foi aplicada a técnica da triangulação, relacionando os dados da análise de conteúdo com os da pesquisa documental e confrontando com as melhores práticas levantadas através da pesquisa bibliográfica. O estudo mostra que as principais causas dos desvios estão fortemente relacionadas aos vícios no desenho institucional brasileiro. A conclusão do trabalho mostra que apesar de ambas as empresas terem apresentado propostas de remediação das deficiências, mediante alterações em seus sistemas de governança corporativa, gestão de riscos e conformidade, em concordância com os padrões do COSO e ISO 31000, apenas a Petrobras implementou efetivamente tais alterações, enquanto que a Eletrobras não havia implementado as necessárias remediações, até o fechamento da presente pesquisa. / ABSTRACT The goal of this work is to analyze the main changes in the corporate governance, risk management and compliance systems of the Petrobras and Eletrobras and verify if these changes were appropriate to remedy the deficiencies that led to the misappropriation of resources identified by Lava Jato Operation. The relevance of the research is mainly on the analysis of measures taken by the two companies based on the evidence that a complex corruption scheme had been carrying out large deviations of resources despite the fact that the two companies are the largest Brazilian state companies, whose reputation was good and their control systems certified nationally and internationally. Through documentary research and others sources it is presented an analysis of the events and the measures that both companies implemented. To evaluate the remediation of the deficiencies in internal controls and governance changes, submitted by the companies, it was used content analysis. Finally, the technique of triangulation was applied, relating the content analysis data with the documentary research and comparing the best practices raised through literature. The main problems were intrinsically associated with the Brazilian institutional problems. As a result, it was possible to identify that both companies submitted control remediation proposals and governance changes in accordance with the standards of COSO and ISO 31,000. However, only Petrobras has implemented a major restructuring in its systems of corporate governance, risk management and compliance.
145

Characterisation of volcanic emissions through thermal vision / Caractérisation des émissions volcaniques par la vision thermique

Bombrun, Maxime 01 October 2015 (has links)
En avril 2010, l’éruption de l’Eyjafjallajökull (Islande) a projeté des cendres sur toute l’Europe pendant six jours, causant d’importantes perturbations aériennes. Cette crise a soulevé la nécessité de mieux comprendre la dynamique des panaches lors de l’émission, de la dispersion, et de la retombée afin d’améliorer les modèles de suivis et de prédiction de ces phénomènes. Cette éruption a été classée comme Strombolienne. Ce type d’éruption offre un large panel de manifestations (coulée de lave, paroxysmes) et peut être utilisé comme indicateur d’éruptions plus dangereuses. Les éruptions stromboliennes permettent généralement une observation à quelques centaines de mètres tout en assurant la sécurité des opérateurs et du matériel. Depuis 2001, les caméras thermiques ont été de plus en plus utilisées pour comprendre la dynamique des évènements volcaniques. Toutefois, l’analyse, la modélisation et le post-traitement de ces données thermiques n’est toujours pas totalement informatisé. Durant ma thèse, j’ai étudié les différentes composantes d’une éruption strombolienne depuis les fines particules éjectées au niveau du cratère jusqu’à la vision d’ensemble offerte par les images satellites. Dans l’ensemble, j’ai caractérisé les émissions volcaniques à travers l’imagerie thermique. / In April 2010, the eruption of Eyjafjallajökull (Iceland) threw volcanic ash across northwest Europe for six days which led to air travel disruption. This recent crisis spotlighted the necessity to parameterise plume dynamics through emission, dispersion and fall out as to better model, track and forecast cloud motions. This eruption was labeled as a Strombolian-to-Sub-Plinian eruption type. Strombolian eruptions are coupled with a large range of volcanic event types (Lava flows, paroxysms) and eruption styles (Hawaiian, Sub-plinian) and offer a partial precursory-indicator of more dangerous eruptions. In addition, strombolian eruptions are small enough to allow observations from within few hundred meters with relative safety, for both operators and material. Since 2001, thermal cameras have been increasingly used to track, parameterise and understand dynamic volcanic events. However, analyses, modelling and post-processing of thermal data are still not fully automated. In this thesis, I focus on the different components of strombolian eruptions at the full range of remote sensing spatial scales. These range from millimeters for particles to kilometers for the entire features via satellite images. Overall, I aim to characterise volcanic emissions through thermal vision.
146

Physical Volcanology, Kinematics, Paleomagnetism, and Anisotropy of Magnetic Susceptibility of the Nathrop Volcanics, Colorado

Hernandez, Brett M. 17 June 2014 (has links)
No description available.
147

Benthic habitats of the extended Faial Island shelf and their relationship to geologic, oceanographic and infralittoral biologic features

Tempera, Fernando January 2009 (has links)
This thesis presents a new template for multidisciplinary habitat mapping that combines the analyses of seafloor geomorphology, oceanographic proxies and modelling of associated biologic features. High resolution swath bathymetry of the Faial and western Pico shelves is used to present the first state-of-the-art geomorphologic assessment of submerged island shelves in the Azores. Solid seafloor structures are described in previously unreported detail together with associated volcanic, tectonic and erosion processes. The large sedimentary expanses identified in the area are also investigated and the large bedforms identified are discussed in view of new data on the local hydrodynamic conditions. Coarse-sediment zones of types hitherto unreported for volcanic island shelves are described using swath data and in situ imagery together with sub-bottom profiles and grainsize information. The hydrodynamic and geological processes producing these features are discussed. New oceanographic information extracted from satellite imagery is presented including yearly and seasonal sea surface temperature and chlorophyll-a concentration fields. These are used as proxies to understand the spatio-temporal variability of water temperature and primary productivity in the immediate island vicinity. The patterns observed are discussed, including onshore-offshore gradients and the prevalence of colder/more productive waters in the Faial-Pico passage and shelf areas in general. Furthermore, oceanographic proxies for swell exposure and tidal currents are derived from GIS analyses and shallow-water hydrographic modelling. Finally, environmental variables that potentially regulate the distribution of benthic organisms (seafloor nature, depth, slope, sea surface temperature, chlorophyll-a concentration, swell exposure and maximum tidal currents) are brought together and used to develop innovative statistical models of the distribution of six macroalgae taxa dominant in the infralittoral (articulated Corallinaceae, Codium elisabethae, Dictyota spp., Halopteris filicina, Padina pavonica and Zonaria tournefortii). Predictive distributions of these macroalgae are spatialized around Faial island using ordered logistic regression equations and raster fields of the explanatory variables found to be statistically significant. This new approach represents a potentially highly significant step forward in modelling benthic communities not only in the Azores but also in other oceanic island shelves where the management of benthic species and biotopes is critical to preserve ecosystem health.
148

Contraintes sur les processus de dégazage des dorsales océaniques par la géochimie des volatils et la pétrologie des laves basaltiques / Constraints on degassing processes at mid-oceanic ridges using volatile geochemistry and petrology

Colin, Aurélia 06 December 2010 (has links)
Afin de préciser l'origine des volatils terrestres et les flux actuels et passés vers l’atmosphère, de nombreuses études s’intéressent à la composition du manteau. Ce réservoir est échantillonné naturellement lors des éruptions volcaniques, mais une grande partie des gaz est alors émise dans l'atmosphère, de sorte que la composition des volatils du manteau reste peu contrainte. Nous cherchons à préciser les mécanismes de dégazage sous les dorsales océaniques afin de corriger ces fractionnements. L'analyse (He-Ne-Ar-CO2) de verres basaltiques issus de la dorsale des Galápagos, dans la zone d'influence du point chaud des Galápagos, montre que la composition en volatils des laves s'explique par distillation de Rayleigh d'une source unique. Cette source est distincte de celle du point chaud (isotopes du néon), impliquant un dégazage en profondeur du panache ou une hétérogénéité spatiale de sa composition.Plusieurs verres volcaniques issus de la dorsale Atlantique et Est Pacifique ont été imagés par micro-tomographie aux rayons X. L'étude met en évidence des mécanismes de nucléation et de croissance des bulles différents sous les deux dorsales. De la convection en périphérie de la chambre magmatique avant l’éruption a été mise en évidence par l’étude pétrologique des verres. Les vésicules imagées ont ensuite été ouvertes individuellement sous vide par ablation laser et analysées (CO2, 4He, isotopes de l'argon). La composition des bulles est hétérogène dans certains échantillons et compatible avec une distillation de Rayleigh. Les tendances de dégazage obtenues permettent d'obtenir localement la composition de la source mantellique, qui est hétérogène.L'étude permet également d'appréhender l'hétérogénéité des rapports 40Ar/36Ar dans les chambres magmatiques par la technique d’ablation laser qui diminue la contamination atmosphérique par rapport à la technique classique de broyage / The composition of mantle volatiles is related to the origin of Earth's volatiles and to the past and present volatile fluxes to the atmosphere. Although this reservoir is naturally sampled during volcanic eruptions, most of the volatiles are lost to the atmosphere during this event, thus the composition of mantle volatiles is still uncertain. We try here to precise the processes of degassing below mid-oceanic ridges to correct the lava compositions for degassing.The He-Ne-Ar-CO2 analyses of basaltic glasses sampled along the Galapagos Spreading Center, in the area of influence of the Galapagos hotspot, show that the volatile composition of lavas is fully explained by a Rayleigh distillation of a unique source distinct from the plume source. These results imply that the plume degasses at depth or is heterogeneous.Several volcanic glasses from Mid-Atlantic ridge and East Pacific Rise have been imaged by X-rays microtomography. The mechanisms of vesicle nucleation and growth appear to be different below the two ridges. A step of convection at the magma body margin has been evidenced by the petrologic study of the glasses. Imaged vesicles have been subsequently opened under vacuum by laser ablation and analysed (CO2, 4He, argon isotopes). We observe, depending on the samples, either a single composition for all bubbles, or variations in composition between bubbles consistent with a trend of equilibrium degassing in an open system. The trends of degassing allow extrapolating locally to the volatile composition of the mantle source, which is heterogeneous. We also studied the heterogeneity of 40Ar/36Ar ratios in magmatic chambers using the laser opening method, which lowers the contribution of atmospheric gases compared to the classical crushing method
149

Modélisation multi-physique des écoulements viscoplastiques : application aux coulées de lave volcanique / Multiphysics modeling of viscoplastic flows : application to volcanic lava flows

Bernabeu, Noé 03 February 2015 (has links)
Nous présentons une contribution autour de la modélisation des écoulements viscoplastiques. En vue d'applications réalistes telle que la simulation numérique des coulées de lave volcanique, le travail se concentre particulièrement sur les fluides complexes dont la rhéologie dépend fortement de grandeurs physiques telle que la température ou la concentration en particule. Nous développons un nouvel algorithme de résolution numérique des équations de Herschel-Bulkley combinant une méthode de Lagrangien augmenté à paramètre d'augmentation variable, une méthode des caractéristiques d'ordre 2 et une adaptation de maillage automatique. Sur des problèmes stationnaires ou en évolution tel que le problème test de la cavité entraînée, il apporte une solution efficace pour garantir à la fois une précision numérique élevée et un temps de calcul raisonnable. Cet algorithme est ensuite étendue et adapté au cas des rhéologies non-isothermes et aux suspensions. Concernant la simulation numérique des coulées de lave volcanique, nous détaillons une méthode de réduction par analyse asymptotique des équations de Herschel-Bulkley pour des écoulements de faible épaisseur sur une topographie arbitraire. Elle permet alors de décrire ces écoulements tridimensionnels de fluides viscoplastiques à surface libre par des équations bidimensionnelles surfaciques. Cette approche est ensuite étendue au cas non-isotherme en y ajoutant l'équation de la chaleur et des dépendances thermiques sur la rhéologie. Par intégration verticale de l'équation de la chaleur, on retrouve un modèle bidimensionnel. Le modèle non-isotherme est validé sur une expérience de dôme réalisée en laboratoire et une simulation numérique est réalisée autour d'une coulée qui a eu lieu sur le volcan du Piton de la Fournaise à la Réunion, en décembre 2010. La comparaison donne des résultats qui sont de notre point de vue satisfaisants et encourageants. / We present a contribution about modeling of viscoplastic flows. For realistic applications such as numerical simulation of volcanic lava flows, the work focuses particularly on complex fluids whose rheology strongly depends on physical quantities such as temperature or the particle concentration. We develop a new numerical resolution algorithm of Herschel-Bulkley's equations combining an augmented Lagrangian method with variable augmentation parameter, a second order characteristic method and an auto-adaptive mesh procedure. On stationary or evolving problems as the lid-driven cavity flow benchmark, it provides an effective solution to ensure both a high numerical accuracy within a reasonable computing time. This algorithm is then extended and adapted to the case of non-isothermal rheological and suspensions. On the numerical simulation of volcanic lava flows, we describe a method of reducing by asymptotic analysis of the Herschel-Bulkley's equations for thin flows on arbitrary topography. It allows to describe the three-dimensional flows of viscoplastic fluid with free surface by bidimensional surface equations. This approach is then extended to the non-isothermal case by adding the heat equation and thermal dependencies on rheology. By vertical integration of the heat equation, a two-dimensional model is maintained . The non-isothermal model is validated on a laboratory experiment of dome and a numerical simulation is performed on a December 2010 Piton de la Fournaise lava flow from La Réunion island. In our view, the comparison gives satisfactory and encouraging results.
150

Modélisation multi-physique des écoulements viscoplastiques : application aux coulées de lave volcanique / Multiphysics modeling of viscoplastic flows : application to volcanic lava flows

Bernabeu, Noé 03 February 2015 (has links)
Nous présentons une contribution autour de la modélisation des écoulements viscoplastiques. En vue d'applications réalistes telle que la simulation numérique des coulées de lave volcanique, le travail se concentre particulièrement sur les fluides complexes dont la rhéologie dépend fortement de grandeurs physiques telle que la température ou la concentration en particule. Nous développons un nouvel algorithme de résolution numérique des équations de Herschel-Bulkley combinant une méthode de Lagrangien augmenté à paramètre d'augmentation variable, une méthode des caractéristiques d'ordre 2 et une adaptation de maillage automatique. Sur des problèmes stationnaires ou en évolution tel que le problème test de la cavité entraînée, il apporte une solution efficace pour garantir à la fois une précision numérique élevée et un temps de calcul raisonnable. Cet algorithme est ensuite étendue et adapté au cas des rhéologies non-isothermes et aux suspensions. Concernant la simulation numérique des coulées de lave volcanique, nous détaillons une méthode de réduction par analyse asymptotique des équations de Herschel-Bulkley pour des écoulements de faible épaisseur sur une topographie arbitraire. Elle permet alors de décrire ces écoulements tridimensionnels de fluides viscoplastiques à surface libre par des équations bidimensionnelles surfaciques. Cette approche est ensuite étendue au cas non-isotherme en y ajoutant l'équation de la chaleur et des dépendances thermiques sur la rhéologie. Par intégration verticale de l'équation de la chaleur, on retrouve un modèle bidimensionnel. Le modèle non-isotherme est validé sur une expérience de dôme réalisée en laboratoire et une simulation numérique est réalisée autour d'une coulée qui a eu lieu sur le volcan du Piton de la Fournaise à la Réunion, en décembre 2010. La comparaison donne des résultats qui sont de notre point de vue satisfaisants et encourageants. / We present a contribution about modeling of viscoplastic flows. For realistic applications such as numerical simulation of volcanic lava flows, the work focuses particularly on complex fluids whose rheology strongly depends on physical quantities such as temperature or the particle concentration. We develop a new numerical resolution algorithm of Herschel-Bulkley's equations combining an augmented Lagrangian method with variable augmentation parameter, a second order characteristic method and an auto-adaptive mesh procedure. On stationary or evolving problems as the lid-driven cavity flow benchmark, it provides an effective solution to ensure both a high numerical accuracy within a reasonable computing time. This algorithm is then extended and adapted to the case of non-isothermal rheological and suspensions. On the numerical simulation of volcanic lava flows, we describe a method of reducing by asymptotic analysis of the Herschel-Bulkley's equations for thin flows on arbitrary topography. It allows to describe the three-dimensional flows of viscoplastic fluid with free surface by bidimensional surface equations. This approach is then extended to the non-isothermal case by adding the heat equation and thermal dependencies on rheology. By vertical integration of the heat equation, a two-dimensional model is maintained . The non-isothermal model is validated on a laboratory experiment of dome and a numerical simulation is performed on a December 2010 Piton de la Fournaise lava flow from La Réunion island. In our view, the comparison gives satisfactory and encouraging results.

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