L’évolution des galaxies est un sujet relativement débattu en astronomie extra-galactique, étant donné que la plupart des mécanismes responsables des propriétés observées dans les galaxies (masse, taux de formation d’étoiles, contenu en métaux, moment angulaire) sont encore peu contraints et certains ne sont probablement même pas encore observés. Ma thèse porte sur une analyse de la région entourant les galaxies, connue sous le nom de Milieu Circum Galactique (MCG). Le MCG est à l’interface entreles galaxies et le Milieu Inter Galactique (MIG) et est considéré comme le lieu de prédilection pour les échanges gazeux et énergétiques entre les galaxies et le MIG, ce qui en fait la clé pour une meilleure compréhension de l’évolution des galaxies et du destin des baryons. Je présenterai dans un premier temps l’analyse d’un échantillon de systèmes à forte absorption issuent de la spectroscopie de quasars en absorption qui tracent les régions denses en hydrogène généralement associées au MCG des galaxies.Dans un deuxième temps, je présenterai ma contribution au développement d’une mission ballon embarquant un spectrographe UV, FIREBall-2, spécialement conçu pour observer l’émission faible et diffuse du MCG des galaxies à décalage vers le rouge inférieur à 1. D’un point de vue technique, je présenterai l’étude du composant optique clé de l’instrument: le réseau. D’un point de vue modélisation, je décrirai une simulation complète des observations, qui servira à la préparation du vol prévu pour l’Automne 2017notamment en ce qui concerne la sélection des cibles, la stratégie observationelle et le traitement des données. / The evolution of galaxies is a rather hot topic in extra galactic astronomy, as many of the main mechanisms underlying the observed properties of galaxies (mass, star formation rate, metal content, angular momentum) are still poorly constraints and many of them are probably undiscovered yet. My thesis focuses on an analysis of the region surrounding galaxies, known as the Circum Galactic Medium (CGM). The CGMinterfaces the galaxy with the Inter Galactic Medium (IGM) and is thought to be the most active location for gas and energy exchanges (in and out), which makes it a key ingredient towards a better understanding of galaxy evolution and the fate of all baryons. I will present in a first part, the analysis of a sample of strong absorption features based on quasar absorption spectroscopy, that probe the dense neutral hydrogen usually associated with galaxies’ CGM. In a second part, I will present my contribution to the development of a balloon-borne UV spectrograph, FIREBall-2, specifically designed to observe the faint and diffuse emissions from the CGM of galaxies at redshifts below 1. On the technical side, I will present the characterization of the key optical component ofthe instrument: the grating. On the modeling side, I will focus on an end-to-end pixel simulation of the observations to prepare for the upcoming flight, planned for Autumn 2017, in terms of target selection, observational strategy and data analysis.

A model has been developed to assess the hazard presented by a condensed phase explosion in a built-up area. The principal application of this model is as an aid to quantitative risk assessment (QRA) of operations involving the transport of high explosive substances' and articles by road or by rail. The methodology employed is to utilise a consequence model in conjunction with a scenario model. The consequence model is used to establish as a function of distance the intensities of the various explosion phenomena and then to estimate, again as a function of distance, the injuries that are likely to result. This yields probabilities that persons will become casualties of the accident, given that people are exposed to the hazard. This effectively determines the level of individual risk as a function of distance. The scenario model is employed to define the location of the population in terms of its vulnerability (exposure) at the time of the explosion. This enables the total number of casualties to be estimated and is effectively a measure of societal risk. Elements of the consequence model include submodels for housing damage and. indoor injury; window breakage and injury from flying glass; air blast and injury by lung damage, eardrum rupture and impact as a result of bodily displacement; fireball and bum injury; generation, flight and wounding power of primary fragments; other explosion ejecta; and falling building debris (glass and masonry). The overall model has been implemented as a computer program, 'EXMOD'. The primary fragmentation submodel has been used as the basis of another, 'EXFRAG'. Many of the results presented in this thesis have been obtained with the aid of these computer programs.

We studied the wurtzite to rock salt phase transition in gallium nitride ( GaN ). Using the mapping algorithm of COMSUBS we found 435 possible mechanisms for this transition. We then used FIREBALL to do density functional theory calculations and found enthalpy barrier heights for the transition pathway. We used this to determine the mechanisms that are the most favorable for GaN. The most favorable mechanisms for GaN are those that break no bonds during the phase transition. The bond-preserving mechanisms involve bilayer sliding of (010) hexagonal plane in the plus or minus [100] hexagonal direction.

I used ab initio molecular dynamics calculations to model cadmium sulfide nanoparticles. The nanoparticles were originaly spherical, bulk-like zinc-blende structures. Constant temperature molecular dynamics calculations reveals that CdS nanoparticles that are about 2 nm in diameter and have unpassivated surfaces are in an amorphous structure with short range order. The nearest neighbor distance on the surface of the nanoparticles being near the wurtzite nearest neighbor distance. I wrote the program xyzSTATS and used its results in justifying the amorphous nanoparticles claim. I also estimated the band gap of the CdS nanoparticles with unpassivated dangling bonds.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23703号 / 理博第4793号 / 新制||理||1686(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 井岡 邦仁, 教授 萩野 浩一, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

O presente estudo analisa as transformações por que o Bólide passa no decurso da obra de Hélio Oiticica, na qual assume diferentes aspectos de 1963 a 1980. Pode-se dizer que, mais do que configurar objetos ou mesmo proposições, o Bólide oferece possibilidades abertas a um comportamento criativo. Ele é parte constitutiva de uma dinâmica própria ao Programa de Oiticica que redimensiona e rearticula seus elementos continuamente; é na particularidade dessa dinâmica que deve ser abordado. No processo experimental do artista, a cada inscrição, o Bólide instaura uma nova significação ele possui tantas significações quantas foram suas inscrições , de modo que estudá-lo implica restabelecer constantemente articulações de significados. Primeiramente, então, o estudo aborda os Bólides cujas estruturas estão vinculadas às experiências do artista com a cor. Entende-se que essas peças ampliam os limites formais do objeto por meio do corpo da cor. Num segundo momento, a análise incide sobre os Bólides configurados a partir de materiais retirados do contexto local, tais como brita, conchas e lata. A especificidade desses elementos, conjugada com uma estrutura formal aberta, reforça o anseio de Oiticica por instaurar uma experiência artística de cunho autônomo. Em seguida, o estudo dedica-se aos Bólides relacionados com os conceitos de suprasensorial e crelazer, que se estruturam como extensões do corpo do participador e podem atingir a escala arquitetônica. Por fim, são abordados o Para-bólide e os Contra-bólides, que trazem uma nova dimensão a essa ordem propositiva. / This study analyzes the transformations that the Bólide (Fireball) undergoes throughout the work of Hélio Oiticica, when from 1963 to 1980, it takes on different aspects. It can be said that more that shaping objects or even proposals, the Bólide discloses new possibilities for a creative behavior. The Bólide is a component of dynamics inherent to Oiticicas program that continuously reshape and rearticulate its elements. It is in the peculiarity of these dynamics that it should be approached. Studying them involves a constant renewal of new mingling of meanings. First then, the study approaches the Bólides whose structures are tied to the artists experiences with color. It is perceived that these pieces expand the formal boundaries of the object by means of the body of color. In a second instance, analysis focuses on the Bólides fashioned from materials taken from the local context such as gravel, shells and tin. The specificity of these elements together with an open formal structure strengthens Oiticicas craving to implant an artistic experience with an autonomous imprint. From then on, the study is centered on the Bólides related with concepts of supersensorial and creleisure, which are structured as extensions of the participants body and may attain an architectural scale. And finally, the Para-bólide and the Contra-bólides that bring forth a new dimension to this proposed order are approached.

O presente estudo analisa as transformações por que o Bólide passa no decurso da obra de Hélio Oiticica, na qual assume diferentes aspectos de 1963 a 1980. Pode-se dizer que, mais do que configurar objetos ou mesmo proposições, o Bólide oferece possibilidades abertas a um comportamento criativo. Ele é parte constitutiva de uma dinâmica própria ao Programa de Oiticica que redimensiona e rearticula seus elementos continuamente; é na particularidade dessa dinâmica que deve ser abordado. No processo experimental do artista, a cada inscrição, o Bólide instaura uma nova significação ele possui tantas significações quantas foram suas inscrições , de modo que estudá-lo implica restabelecer constantemente articulações de significados. Primeiramente, então, o estudo aborda os Bólides cujas estruturas estão vinculadas às experiências do artista com a cor. Entende-se que essas peças ampliam os limites formais do objeto por meio do corpo da cor. Num segundo momento, a análise incide sobre os Bólides configurados a partir de materiais retirados do contexto local, tais como brita, conchas e lata. A especificidade desses elementos, conjugada com uma estrutura formal aberta, reforça o anseio de Oiticica por instaurar uma experiência artística de cunho autônomo. Em seguida, o estudo dedica-se aos Bólides relacionados com os conceitos de suprasensorial e crelazer, que se estruturam como extensões do corpo do participador e podem atingir a escala arquitetônica. Por fim, são abordados o Para-bólide e os Contra-bólides, que trazem uma nova dimensão a essa ordem propositiva. / This study analyzes the transformations that the Bólide (Fireball) undergoes throughout the work of Hélio Oiticica, when from 1963 to 1980, it takes on different aspects. It can be said that more that shaping objects or even proposals, the Bólide discloses new possibilities for a creative behavior. The Bólide is a component of dynamics inherent to Oiticicas program that continuously reshape and rearticulate its elements. It is in the peculiarity of these dynamics that it should be approached. Studying them involves a constant renewal of new mingling of meanings. First then, the study approaches the Bólides whose structures are tied to the artists experiences with color. It is perceived that these pieces expand the formal boundaries of the object by means of the body of color. In a second instance, analysis focuses on the Bólides fashioned from materials taken from the local context such as gravel, shells and tin. The specificity of these elements together with an open formal structure strengthens Oiticicas craving to implant an artistic experience with an autonomous imprint. From then on, the study is centered on the Bólides related with concepts of supersensorial and creleisure, which are structured as extensions of the participants body and may attain an architectural scale. And finally, the Para-bólide and the Contra-bólides that bring forth a new dimension to this proposed order are approached.

We have expanded the capabilities of the ab initio tight-binding molecular dynamics package FIREBALL to include calculations of optical properties. Basic zero order approximation is based on transitions between Kohn-Sham states. Corrections for electron-electron interactions are based on time dependant density functional theory (TDDFT). Consistent with the FIREBALL approach, we use precalculated integrals and approximations to make the program faster.

This thesis contends that the image of fire is a multivalent and theologically valuable image for application in British Christian communities. My research offers an original contribution by contextualising the image of fire for Christian practice in Britain, and combining critical observation of several contemporary fire rites with theological analysis. In addition, I conduct original case studies of three Scottish fire rituals: the Stonehaven Fireball Ceremony, the Beltane Fire Festival, and Up-Helly-Aa in Lerwick, Shetland. The potential contribution of fire imagery to Christian practice has been overlooked by modern theological scholarship, social anthropologists, and Christian practitioners. Since the multivalence of the image has not been fully recognised, fire imagery has often been reduced to a binary of ‘positive' and ‘negative' associations. Through my study of non-faith fire rituals and existing Christian fire practices, I explore the interplay between multivalence, multiplicity, and liminality in fire imagery. I demonstrate that deeper theological engagement with the image of fire can enhance participation, transformation, and reflection in transitional ritual experience. I argue that engaging with the multivalence of the image of fire could allow faith communities to move beyond dominant interpretive frameworks and apply the image within their own specific context. First, I orientate the discussion by examining the multivalence of biblical fire imagery and establishing the character of fire within the British social imagination. Second, I use critical observation of community fire practices in non-faith contexts to build a new contextual framework for the analysis of fire imagery. Finally, I apply my findings to a contextual analysis of existing Christian fire practices in Britain. Throughout, I argue that sensory and imaginative interaction with the image of fire provides a way to communicate and interact with theological ideas; experience personal and communal change; and mediate experience of the sacred.