Mixed regimes are often viewed as inherently less stable and more war prone than fully democratic or autocratic systems due to their low levels of institutionalization. I ask, are certain mixed regimes more or less war prone than other mixed regimes, based on the strength and orientation (more democratic or autocratic) of their political institutions? At ends with previous research, my findings suggest that institutionalization levels play little, if any role in the onset of interstate war.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-03-30T13:38:45Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Mikele Cândida Sousa de Sant'Anna.pdf: 2684133 bytes, checksum: 61e61bb0edcf743d1f2af9c55724a92e (MD5) / Made available in DSpace on 2016-03-30T13:38:45Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Mikele Cândida Sousa de Sant'Anna.pdf: 2684133 bytes, checksum: 61e61bb0edcf743d1f2af9c55724a92e (MD5) Previous issue date: 2015-11-18 / CAPEs / O presente trabalho trata da simulação numérica de um gaseificador de leito fluidizado borbulhante fazendo uso da CFD para o sistema composto por gás-biomassa-areia. Inicialmente, simulou-se os sistemas gás-areia e gás-biomassa. O modelo computacional empregado foi validado empregando-se os resultados experimentais de Taghipuor et al. (2005).A seguir, foi realizado um planejamento fatorial 23, onde se variou a massa específica e o diâmetro da partícula e o percentual de biomassa na fase sólida. Para realizar as simulações foram utilizados os softwares ANSYS CFX 15.0 e ANSYS FLUENT 15.0, adotando-se a abordagem euleriana, com a Teoria Cinética de Escoamento Granular. As seguintes velocidades superficiais do gás foram testadas: 0,03, 0,1, 0,38 0,46 e 0,51 m.s-1. Para o sistema gás-areia, o leito permaneceu fixo nas velocidades de 0,03 e 0,10 m.s-1. Aos 2,50 s de simulação transiente, o leito encontrava-se fluidizado para as velocidades maiores ou iguais a 0,38 m.s-1 e assim permaneceu alcançando um estado pseudo-estacionário. No sistema gás-biomassa, o leito manteve-se fixo apenas na velocidade de 0,03 m.s-1. Dois sistemas foram testados com três componentes (gás-areia-biomassa) diferenciando-se entre si pelos tamanhos das partículas de areia e biomassa. Para grandes diferenças entre estes tamanhos, o sistema apresentou segregação durante a fluidização. No sistema com menor diferença nestes tamanhos, a fluidização ocorreu mais facilmente, uma vez que os efeitos de segregação foram atenuados. Foram obtidos perfis de fração volumétrica do gás, areia e biomassa para as 17 condições do planejamento fatorial, bem como um modelo que prediz a expansão do leito em sistemas fluidizados. O ensaio que apresentou maior altura final do leito (0,50 m), mantendo-se em regime borbulhante, foi aquele com 15% de partículas de biomassa com 375 m de diâmetro e 85% de areia, sendo, portanto, uma condição ótima para a fluidização. / This work has studied a bubbling fluidized bed gasifier though numerical simulation using computational fluid dynamics (CFD) for the system composed of gas - biomass - sand. Initially, gas-sand and gas-biomass systems were simulated. The computer model used was validated employing experimental results from Taghipuor et al. (2005) .Then, a 23 factorial design was employed, where the density, the particle diameter and the the fraction of biomass were varied. All simulations were carried out using ANSYS CFX 15.0 and ANSYS FLUENT 15.0. An eulerian approach coupled to the Kinetic Theory of Granular Flow were used. The following gas superficial velocities were tested: 0.03, 0.1, 0.38, and 0.46 0.51 m s-1. For gas-sand system, a fixed bed was obtained for gas velocities of 0.03 and 0.10 m s-1. After 2.50 s of transient simulation, the bed became fluidized for gas velocities greater or equal to 0.38 m s-1 staying in a pseudo-steady state. For the biomassgas system, the bed remained fixed only at the speed of 0.03 m s-1. Two systems were tested using the three components (gas, sand and biomass) differing from each other only by the size of sand and biomass particles. For high differences between these sizes, the system showed segregation during fluidization. In the system with lower size difference, the fluidization occurred more easily, since the segregation effects were attenuated. Volumetric fraction profiles of gas, sand and biomass were obtained for the 17 factorial design conditions used as well as a model that predicts the bed expansion in fluidized systems. The assay that showed higher final height of the bed (0.50 m) staying in a bubbling regime was one with 15% biomass particles with 375 mm in diameter and 85% of sand, being, therefore, a good condition to carry out fluidization.

Orientador: Paulo Cesar Rocha / Resumo: O regime hidrológico do rio Madeira é caracterizado pela sazonalidade dos volumes de água na bacia hidrográfica. As variações do clima e as ações antrópicas são os principais responsáveis pelas alterações nestes volumes. Para avaliar tais mudanças alguns indicadores podem ser analisados levando em consideração períodos com regime de fluxo natural e alterado. Os Indicadores de Alteração Hidrológica (IAH) são ideais para comparar regimes hidrológicos afetados por usinas hidrelétricas, que criam barreiras no fluxo natural e modificam o regime de vazões. Calculados com métodos paramétricos e não paramétricos, o IAH leva em consideração as análises das estatísticas de médias, desvio padrão e percentuais dos hidrogramas fluviais. No rio Madeira, as hidrelétricas de Jirau (3.750 MW) e Santo Antônio (3.568 MW) entraram em operação a fio d’água no ano de 2012. Como resultado este trabalho apresentou anos úmidos após o término destas obras hidráulicas gerando vazões mais altas que as médias do período anterior as usinas. O ano de 2014 (grande cheia) pode ser considerado um ano atípico e pode ter camuflado os resultados, elevando as médias de vazões e outros indicadores observados no IAH, denominado período pós impactos. Além das variações de vazões bem definidas nos períodos úmido e seco, a bacia hidrográfica do Madeira é uma grande produtora e transportadora de sedimentos. Foram encontrados valores médios de retenção de sedimentos pelos barramentos na ordem de 17%, o que pode indicar ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The hydrological regime of the Madeira River is characterized by the seasonality of water volumes in the river basin. The changes in climate and anthropic actions are mainly responsible for the changes in these volumes. In order to evaluate such changes some indicators can be analyzed taking into account periods with natural and modified flow regime. The Indicators of Hydrological Alteration (IHA) are ideal for comparing hydrological regimes affected by hydroelectric plants, which create barriers in the natural flow and modify the flow regime. Calculated using parametric and nonparametric methods, the IHA takes into account the statistical analysis of means, standard deviation and percentages of fluvial hydrograms. In the Madeira River, Jirau hydroelectric plants (3,750 MW) and Santo Antônio (3,568 MW) entered operation in 2012 and result this paper presented wet years after the completion of these hydraulic works. The year 2014 (large flood) can be considered an atypical year and may have camouflaged the results, raising the averages of flows and other indicators observed in the IHA, called post-impact period. In addition to well-defined variations and flows in the wet and dry periods, the Madeira basin is a major producer and sediment conveyor. Averages values of sediment retention were found in the order of 17% of suspened sediment. / Mestre

The understanding and study of electron transport in semiconductor systems has been the instigation behind the growth of semiconductor electronics industry which has enabled technological developments that are part of our everyday lives. However, most materials exhibit diffusive electron transport where electrons scatter off disorder (impurities, phonons, defects, etc.) inevitably present in the system, and lose their momentum. Advances in material science have led to the discovery of materials which are essentially disorder-free and exhibit exceptionally high mobilities, enabling transport physics beyond diffusive transport. In this work, we explore non-diffusive transport regimes, namely, the ballistic and hydrodynamic regimes in a high-mobility two-dimensional electron system in a GaAs quantum well in a GaAs/AlGaAs heterostructure. The hydrodynamic regime exhibits collective fluid-like behavior of electrons which leads to the formation of current vortices, attributable to the dominance of electron-electron interactions in this regime. The ballistic regime occurs at low temperatures, where electron-electron interactions are weak, constraining the electrons to scatter predominantly against the device boundaries. To study these non-diffusive regimes, we fabricate mesoscopic devices with multiple point contacts on the heterostructure, and perform variable-temperature (4.1 K to 40 K) zero-field nonlocal resistance measurements at various locations in the device to map the movement of electrons. The experiments, along with interpretation using kinetic simulations, demarcate hydrodynamic and ballistic regimes and establish the dominant role of electron-electron interactions in the hydrodynamic regime. To further understand the role of electron-electron interactions, we perform nonlocal resistance measurements in the presence of magnetic field in transverse magnetic focusing geometries under variable temperature (0.39 K to 36 K). Using our experimental results and insights from the kinetic simulations, we quantify electron-electron scattering length, while also highlighting the importance of electron-electron interactions even in ballistic transport. At a more fundamental level, we reveal the presence of current vortices in both hydrodynamic and surprisingly, ballistic regimes both in the presence and absence of magnetic field. We demonstrate that even the ballistic regime can manifest negative nonlocal resistances which should not be considered as the hallmark signature of hydrodynamic regime. The work sheds a new light on both hydrodynamic and ballistic transport in high-mobility solid-state systems, highlighting the similarities between these non-diffusive regimes and at the same time providing a way of effectively demarcating them using innovative device design, measurement schemes and one-to-one modeling. The similarities stem from total electron system momentum conservation in both the hydrodynamic and ballistic regimes. The work also presents a sensitive and precise experimental technique for measuring electron-electron scattering length, which is a fundamental quantity in solid-state physics. / Doctor of Philosophy / Electrons are the charged particles that are bound around the nuclei of atoms. But sometimes in a solid material electrons break free away from the nuclei and wander around. They are then the carriers of electric current ubiquitous in our daily lives as in our homes, and in our electronic devices such as smartphones and computers. Often an analogy is made between the flow of electric current in a material and the flow of water in a stream. However, the analogy does not hold well for most materials. In most materials the motion of electrons can be thought of as balls in a pinball machine - their movement hindered and randomized by collisions with the countless defects and impurities present in the material they travel through. However, recently scientists have been able to synthesize ultraclean materials, where electrons can indeed mimic the flow of water under the right conditions. In this aptly-named hydrodynamic regime, electrons predominantly interact with each other and that leads to the formation of current whirlpools or vortices similar to those forming in water. A telling signature of this regime is a negative electrical resistance appearing near the location of the vortex. When the interactions between electrons are weak, such as at very low temperatures, electrons move along straight-line trajectories until they hit and bounce off the device edges, similar to billiard balls. This low-temperature phenomenon is called ballistic transport. In this work we reveal that measurement of negative resistance and formation of current vortices are not unique to the hydrodynamic regime but can occur in the ballistic regime as well. It is indeed counterintuitive that electrons moving like billiards balls can behave similarly to electrons flowing like water. The similarities can be traced back to a fundamental physics conservation law active in both situations, namely momentum conservation. To experimentally realize the tests, we use a very high purity semiconductor material GaAs/AlGaAs and fabricate tiny devices on the material with a cutting-edge design, capable of precisely measuring resistance at various locations along the device to map the movement of electrons. The simulations of the novel physics indeed reveal current vortices of various sizes in the ballistic regime, in agreement with the experimental data showing negative resistance. In another experiment, we apply a magnetic field, making the electrons move in circular paths. If uninterrupted, electrons complete half circles and are collected through an opening in the device, giving resistance peaks in experiments. Due to electron-electron interactions, the electrons on their circular trajectory are interrupted by other electrons which leads to a decay in resistance peaks. This decay is utilized to measure the strength of electron-electron interactions. The work has both fundamental and applied implications. The existence of whirlpools shows that the electron momentum is not lost by collisions, and that in turn means that the conduction of electrical current in these regimes is inherently efficient. This opens up avenues for electronic devices which are faster, more functional and more power efficient than present electronic devices.

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This thesis deals with the problem of determining the reasons behind the purge conducted by various high officials in the Nazi regime on June 30-July 2, 1934.

Die Arbeit untersucht den Einfluss von Nichtregierungsorganisationen (NGOs)und Wissenschaftlicher Gemeinschaften auf Internationale Regime. Ausgehend vom Kooperationsproblem in einer anarchischen Staatenwelt wird der Leistungsbeitrag der beiden nichtstaatlichen Akteure auf das Zustandekommen von Kooperation analysiert und seine schwankende Rolle im Verlauf des Regimeprozesses untersucht. Das Fallbeispiel bildet dabei das internationale Klimaschutzregime, wobei der Untersuchungszeitraum von den ersten Anfängen der Thematisierung des Klimawandels bis hin zu der in Marrakesch erreichten Ausformulierung des Kyoto-Protokolls reicht. / The thesis investigates the influence of non-governmental organizations (NGOs) and scientific communities on international regimes. Starting with the problem of cooperation in an anarchical world the thesis analyses the performance of the two non-state actors on achieving international cooperation and their varying role during the negotiation process. The case study focusses on the International Regime on Climate Change. The period of investigation starts with the beginning of the discussions on climate change and ends with the "Marrakesh Accords" which build the final point of the formulation of the "Kyoto Protocol".

Thesis advisor: Robert C. Bartlett / This thesis seeks to explain why Aristotle considers piety a necessary component of the best regime that he presents in book 7 of the Politics. It argues that Aristotle includes piety in the best regime because the pious belief in divine providence, that is, divine reward for virtuous human beings and punishment for vicious human beings, provides an essential justification for moral virtue that enables the best regime to habituate its citizens in the practice of moral virtue without compelling them to deny their natural longing for happiness. Only this pious conception of divine providence enables the citizens of the best regime to be happy as they cope with the demands of moral virtue and citizenship. / Thesis (MA) — Boston College, 2019. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Political Science.

Cette thèse traite du paradigme du « régime néo-patrimonial », développé notamment par le politologue Jean-François Médard pour décrire la domination africaine. Partant des débats scientifiques qu’il a suscités, l’étude esquisse une concrétisation de ce modèle d’analyse dans cas nationaux : la Côte d’Ivoire et le Cameroun, pays africains en transition démocratique. Dans la lignée des travaux académiques sur la pénétration africaine de la démocratie électorale, la thèse considère cette démocratisation comme un facteur de crise pour les régimes néo-patrimoniaux très ancrés et développe une approche compréhensive de la manière dont le vote et la compétition politique se heurtent à la résistance de deux chefs d’Etat, Paul Biya et Laurent Gbagbo formés à l’imaginaire néo-patrimonial qui incite au perpétualisme. Dans la première partie méthodologique, le premier chapitre présente l’état de la recherche universitaire sur cette théorie et les termes de la controverse qu’elle suscite. Sont ensuite analysées (chapitre 2) les conditions d’inscription de ce paradigme dans les études africanistes comme modèle explicatif de la domination. La deuxième partie développe l’hypothèse d’un « néo-patrimonialisme national » pour analyser les trajectoires hégémoniques et l’émergence indigène des figures de domination (chapitre 3), ainsi que les modalités de la succession organisée par les « pères de la nation », Ahidjo et Houphouët-Boigny, dont la fin de règne a inauguré une crise hégémonique (Cameroun) et sociétale (Côte d’Ivoire) aux ramifications complexes (chapitre 4). La troisième partie observe la cohabitation ambiguë de la domination néo-patrimoniale et de la démocratie électorale qui aurait dû constituer une alternative. Ce paradoxe a un destin national : on analyse les ressources politico-stratégiques qui ont permis au régime néo-patrimonial de Paul Biya de survivre à la pénétration démocratique (chapitre 5), et à celui de Laurent Gbagbo de se fissurer au milieu des jeux d’acteurs et d’enjeux complexes le transcendant (chapitre 6). / This PhD dissertation addresses the neo-patrimonial regime paradigm, developed by Jean-François Médard as theory to explore African domination. Starting by academic debates around this paradigm, the study focus on two national cases: Cote d’Ivoire and Cameroon, two Subsaharian Africa countries (SSAC) in democratic transition process. Keeping the way of academic studies on the electoral democracy penetration process in SSAC, the study considers democratization as critical event for neopatrimonialism, the principal regime of domination in SSAC. The analysis proposes a comprehensive approach of this crisis, observing the terms of contact between votes, political competition and resistance of two heads of state, Paul Biya and Laurent Gbagbo, who are children of neopatrimonalism, the regime of perpetual power. In the first part consecrated to methodology, we present the academic debate around the neopatrimonialism (chapter 1st), looking deeply in the contextualization of this paradigm in Africanist studies (chapter 2). The second part develops the hypothesis of “national neopatrimonialism”, by presenting the local trajectories of hegemonic category and figures of domination (chapter 3). We also observe the constitutional terms of replacement of “Father of the Nation” Ahidjo and Houphouet-Boigny as the origin of hegemonic crisis in Cameroon and part of determinant of civil war in Cote d’Ivoire (chapter 4). The study consider (part 3) the ambiguous cohabitation between neopatrimonialism regime and electoral democracy, the alternative mode of power exercise. This cohabitation makes sense at national level : we specifically analyse resources of Paul Biya long stay in power in time of electoral democracy(chapter 5) and, in contrary, the causes of Gbagbo fall inside this complex games and issues of Cote d’Ivoire crisis (2002-2010) and transition (chapter 6).