Esta dissertação faz parte de um projeto que tem como objetivo investigar a origem e evolução do magmatismo de arco e pós-colisional do Escudo Sul-rio-grandense (ESRG), caracterizando a partir de estudos geoquímicos, estruturais e petrográficos os Granitóides Sanga do Areal (GSA), localizados na região de Quitéria, porção leste do Escudo Sul-rio-grandense. Estes granitóides consistem de dois corpos principais, alongados na direção NE-SW, com aproximadamente 14 km de extensão e 2 km de largura, e também de diversas intrusões menores, posicionadas, preferencialmente, na porção mediana de alta deformação cisalhante do Complexo Arroio dos Ratos. Estão em contato na porção NW com metatonalitos, metagranodioritos e gnaisses tonalíticos a dioríticos de idade paleoproterozóica do referido complexo e com horblenda-biotita granodioritos da unidade neoproterozóica Granodiorito Cruzeiro do Sul. Na porção SE o contato se dá com tonalitos a dioritos relacionados aos Granitóides Arroio Divisa de idade neoproterozóica. Os GSA são biotita monzogranitos de textura porfirítica em seu termo principal, com cerca de 30% de megacristais de até 5 cm de comprimento de plagioclásio e K-feldspato. A matriz heterogranular média a grossa é composta por quartzo fitado, feldspato parcialmente recristalizado e biotita. Subordinadamente, observam-se corpos de espessura centimétrica a métrica de biotita granodiorito equigranular médio, com fenocristais esparsos de feldspatos alinhados na foliação. Raramente ocorrem enclaves microgranulares máficos. A foliação milonítica é bem marcada pela orientação da biotita, dos megacristais lenticulares e do quartzo fitado e tem direção E-W, com alto ângulo de mergulho para N e para S, contendo lineação de estiramento direcional, com baixo caimento para W a SW. A foliação ígnea primária, concordante a sub-concordante com a foliação milonítica, tem ocorrência restrita e é marcada pela orientação dos megacristais não deformados e das lamelas de biotita. Estruturas S-C, caudas assimétricas em porfiroclastos de feldspatos, biotita fish e fitas assimétricas de quartzo são consistentes e indicam movimento transcorrente sinistral. Os Granitóides Sanga do Areal têm afinidade sub-alcalina médio a alto K, provavelmente toleítica, compatível com ambiente pós-colisional, onde foram deformados e controlados por zonas de cisalhamento transcorrente sub-verticais. Foi obtida uma idade U-Pb em zircão dos granitóides de 626,6±4,9 Ma (MSWD=2.2), coerente com as relações de campo. / This research investigates the evolution of arc to post-collisional magmatism in the Sul-rio-grandense Shield (ESGR), using geochemistry, structural and petrographic studies of the Sanga do Areal Granitoids (GSA). These granitoids are located in the Quitéria region, east of ESRG. The GSA form two main, NE-striking intrusions, and several other small ones, mainly within the shear zone croscutting the central portion of the Arroio dos Ratos Complex. The two main bodies are about 14 km long and 2 km wide. To the northwest, the GSA rocks are in contact with Paleoproterozoic metatonalites, metagranodiorites, tonalitic to dioritic gneisses of the Complex, and Neoproterozoic horblende-biotite granodiorites of the Cruzeiro do Sul unit. To the southeast, they are surrounded by tonalitic to dioritic rocks, related to the Neoproterozoic Arroio da Divisa Granitoids. The GSA rocks are composed mainly of porphyritic biotite monzogranites, with about 30% megacrysts of plagioclase and 5 cm long K-feldspar. The medium to coarse grained heterogranular groundmass is composed of microcrystalline ribbon quartz, partially re-crystallized feldspar and biotite. Medium-grained equigranular granodiorite occurs as centimeter to meter- thick bodies, with sparse feldspar megacrysts aligned on the foliation plane. Microgranular mafic enclaves are rarely observed within the GSA rocks. The mylonitic foliation is well-developed and marked by biotite, oriented lenticular megacrysts, as well as quartz ribbons. It strikes E-W and dips at high angles either N or S. The stretching lineation within the foliation shows shallow plunges, preferentially W-SW. A primary igneous foliation is sometimes observed, and it is concordant or sub-concordant with the mylonitic one, and marked by orientation of igneous megacrysts and biotite lamellae. S-C structures, asymetric tails in feldspar porphyroclasts, biotite fish, and asymetric quartz ribbons indicate transcurrent movement with consistent sinistral shear sense. The Sanga do Areal Granitoids show subalkaline medium- to high-K affinity, probably tholeiitic, and trace element composition consistent with sources related to post-collisional settings, which were deformed and controlled by E-NE and NE sub-vertical transcurrent shear zones. A U-Pb age in zircon grains from Sanga do Areal Granitoids of 626.6 ± 4.6Ma ((MSWD=2.2) was obtained and considered coherent with stratigraphic relations.

The cyclic peroxides: diphenoyl peroxide (1), spiro-adamantyl-1,2-dioxetanone (2) and 4-(3-tert-butyldimethylsilyloxyphenyl)-4-methoxyspiro[1.2-dioxetane-3.2\'-adamantane] (3) synthesized, purified and characterized, also their kinetic and chemiluminescence (CL) properties were determined. The influence of solvent polarity on the chemiexcitation parameters of the catalyzed decomposition of 1 and 2, as well as the induced decomposition of 3 were examined in several binary solvent mixtures with different polarity and polarizability parameters, but similar viscosities. For solvents with low polarity, singlet quantum yields for the intermolecular catalyzed decomposition of diphenoyl peroxide (1,) and 1,2-dioxetanone (2) increase in function of medium polarity, showing maximum values in mediums of intermediate polarity, and decreasing in highly polar mixtures. For the induced decomposition of 3, the quantum yield showed to increase with increasing solvent polarity, including high polar solvent systems. In the binary solvent systems studied, the polarizability parameter showed to be contrary to the polarity values, therefore, it might appear that an increase of polarizability leads to a decrease in the singlet quantum yields for catalyzed decomposition of diphenoyl peroxide (1) and the induced decomposition of 3, however an increase in the singlet quantum yields for 1,2-dioxetanone 2. The three CL systems were also studied in binary solvent mixtures with different viscosities but similar polarity and polarizability parameters and singlet quantum yields showed an increase with increasing medium viscosity. Data were analyzed by using the collisional and the free volume models. The highly efficient intramolecular system induced 1,2-dioxetane 3 decomposition showed to be much more sensible to viscosity effects than the inefficient intermolecular systems. This surprising fact indicates that, even showing a significant solvent-cage effect, the induced 1,2-dioxetane should occur by an intramolecular electron back transfer. Moreover, chemiluminescence parameters of these systems were studied in several pure solvents. The obtained singlet quantum yields were correlated with viscosity, polarizability and polarity parameters by using multiple linear regression analysis. / Os peróxidos cíclicos: peróxido de difenoila (1), spiro-adamantil-1,2-dioxetanona (2) e 4-(3-terc-butildimetilsililoxifenil)-4-metoxispiro[1,2-dioxetano-3.2\'-adamantano] (3) foram sintetizados, purificados e caracterizados e as suas propriedades cinéticas e de quimiluminescência (CL) determinadas. A influência da polaridade do solvente sobre os parâmetros de quimi-excitação da decomposição catalisada de 1 e 2, e a decomposição induzida de 3 foi examinada em diversas misturas binárias de solventes com parâmetros de polaridade e polarizabilidade diferente, mas viscosidades semelhantes. Para solventes com baixa polaridade, os rendimentos quânticos singlete para a decomposição catalisada intermolecular do peróxido de difenoila (1) e 1,2-dioxetanona (2) aumentam em função da polaridade do meio, mostrando valores máximos em meios com polaridade intermediária, e diminuim para misturas altamente polares. Para a decomposição induzida de 3, o rendimento quântico mostrou aumentar com o aumento da polaridade do solvente, inclusive para sistemas com alta polaridade. Nos sistemas binários de solventes estudados, os parâmetros de polarizabilidade mostraram-se contrários aos valores de polaridade, portanto, parece que um aumento da polarizability leva a uma diminuição nos rendimentos quânticos singlete para a decomposição catalisada do peróxido de difenoila (1) e a decomposição induzida de 3, no entanto, um aumento nos rendimentos quânticos singlete para a 1,2-dioxetanona 2. Os três sistemas de CL também foram estudados em misturas binárias de solventes com diferentes viscosidades, mas com parâmetros de polaridade e polarizabilidade semelhantes e os rendimentos quânticos singlete mostraram aumentar com o aumento da viscosidade do meio. Os dados foram analisados usando tanto o modelos colisional quando o modelo de volume livre. Surpreendentemente, o sistema altamente eficiente decomposição induzida intramolecular do 1,2-dioxetano 3 mostrou-se muito mais sensível aos efeitos da viscosidade do que os sistemas intermoleculares ineficientes, o que indica claramente que a decomposição induzida do 1,2-dioxetano deve ocorrer por um processo de retro-transferência de elétron intramolecular. Além disso, os parâmetros de quimiluminescência destes sistemas foram estudados em vários solventes puros. Os rendimentos quânticos singlete obtidos foram correlacionados com parâmetros de viscosidade, polarizabilidade e polaridade usando análise de regressão linear múltipla.

Résumé : Ce travail avait pour but de contribuer à la détermination précise des paramètres de raies du disulfure de carbone en vue d'applications atmosphériques. Il s'agissait de déterminer théoriquement et expérimentalement les coefficients d'élargissement collisionnel de raies de la bande gamma 3 du disulfure de carbone perturbé par l'air atmosphérique ainsi que leur dépendance en température. Pour cela, nous avons déterminé les coefficients d'élargissement collisionnel du disulfure de carbone perturbé par l'azote, l'oxygène et enfin par l'argon, principaux composants de l'air atmosphérique, aussi bien que leur dépendance en température. En outre, nous avons déterminé théoriquement et expérimentalement les coefficients d'auto élargissement collisionnel de raies de la bande gamma 3 - gamma 1 du disulfure de carbone, à température ambiante. La dépendance vibrationnelle des largeurs collisionnelles étant négligeable, les résultats sont valables quel que soit le niveau supérieur de la transition. Enfin, nous avons déterminé les intensités absolues de quelques raies de la bande gamma 3 - gamma 1 du disulfure de carbone qui nous ont permis de mettre en exergue une des applications atmosphériques des paramètres de raie mesurés en laboratoire. Pour la partie expérimentale, un spectromètre diode-laser haute résolution (5x10-4cm-1) a été utilisé pour enregistrer les différents spectres. De ces derniers, nous avons déterminé les différents paramètres de raie d'absorption en ajustant aux profils expérimentaux des modèles de profils théoriques. Du point de vue théorique, les différents coefficients d'élargissement collisionnel ont été calculés sur base du formalisme semi-classique d'Anderson-Tsao-Curnutte amélioré par J. Bonamy et D. Robert, moyennant quelques modifications pour accorder les valeurs à celles mesurées en laboratoire. Ceci a permis de valider les différents potentiels d'interaction pour les différents systèmes moléculaires considérés. Abstract The purpose of this thesis was to contribute to the accurate determination of line parameters of carbon disulfide for atmospheric applications. We have determined experimentally as well as theoretically the collisional broadening coefficients of lines in the gamma 3 band of carbon disulfide perturbed by the atmospheric air and their temperature dependence. To this end, we determined collisional broadening coefficients, as well as their temperature dependence, of carbon disulfide diluted in nitrogen, oxygen and argon; the main components of the atmospheric air. In addition, we determined the self broadening coefficients of lines in the gamma 3 - gamma 1 band of carbon disulfide at room temperature. As the vibrational dependence of collisional widths is negligible, our results are valid whatever the higher level of transition. Finally, we determined the absolute intensities of a few lines in the gamma 3 - gamma 1 band of carbon disulfide, which have enabled us to highlight one of the atmospheric applications of line parameters measured in the laboratory. For the experimental part, a high resolution diode-laser spectrometer (5x10-4cm-1) was used to record the different spectra. Of these, we determined the parameters of absorption line by adjusting theoretical lineshape models to experimental profiles. From a theoretical point of view, different collisional broadening coefficients were calculated on the basis of semi classical formalism of Anderson-Tsao-Curnutte improved by J. Bonamy and D. Robert, with some modifications to make the calculated values more consistent with those measured. This enabled us to validate the different potentials of interactions for the different molecular systems considered.

Improving the knowledge of the spectral and temporal properties of plasma-based XUV lasers is an important issue for the ongoing development of these sources towards significantly higher peak power. The spectral properties of the XUV laser line actually control several physical quantities that are important for applications, such as the minimum duration that can be achieved (Fourier-transform limit). The shortest duration experimentally achieved to-date is ~1 picosecond. The demonstrated technique of seeding XUV laser plasmas with a coherent femtosecond pulse of high-order harmonic radiation opens new and promising prospects to reduce the duration to a few 100 fs, provided that the gain bandwidth can be kept large enough.XUV lasers pumped by collisional excitation of Ni-like and Ne-like ions have been developed worldwide in hot plasmas created either by fast electrical discharge, or by various types of high-power lasers. This leads to a variety of XUV laser sources with distinct output properties, but also markedly different plasma parameters (density, temperature) in the amplification zone. Hence different spectral properties are expected. The purpose of our work was then to investigate the spectral behaviour of the different types of existing collisional excitation XUV lasers, and to evaluate their potential to support amplification of pulses with duration below 1 ps in a seeded mode.The spectral characterization of plasma-based XUV lasers is challenging because the extremely narrow bandwidth (typically ∆λ/λ ~10-5) lies beyond the resolution limit of existing spectrometers in this spectral range. In our work the narrow linewidth was resolved using a wavefront-division interferometer specifically designed to measure temporal coherence, from which the spectral linewidth is inferred. We have characterized three types of collisional XUV lasers, developed in three different laboratories: transient pumping in Ni-like Mo, capillary discharge pumping in Ne-like Ar and quasi-steady state pumping in Ne-like Zn. Besides the accurate measurement of the temporal coherence of the laser in each case, we have studied the spectral behaviour when the laser is operated in the saturation regime and (in Ni-like Mo) when it is seeded with high-order harmonic radiation. We have also investigated the temporal behaviour of the Ni-like Mo transient XUV laser, using an ultrafast X-ray streak camera. Our linewidth measurements are compared with detailed numerical calculations including relevant broadening mechanisms as well as radiative transfer effects. The evolution of the spectral profile with amplification and saturation was studied for different plasma parameters, and corresponding Fourier-transform limit duration were evaluated.The shortest temporal coherence (ie the largest bandwidth) is measured for the quasi-steady state pumping XUV laser, which operates at the highest density and ionic temperature.

Das Afterglow tritt am Übergang vom Plasma zur Gasphase auf. Die dominierende aktive Spezies im Afterglow sind metastabil angeregte Neutralteilchen. Der Abbau der Metastabilen erfolgt in drei verschiedenen Prozessen: dem radiativen Zerfall, den Quenching-Stößen sowie der Relaxation in Stößen mit Oberflächen. Potentielle Anwendungsmöglichkeiten des Afterglows für Schichtabscheidung und Oberflächenmodifizierung werden diskutiert. Zur theoretischen Beschreibung des strömenden Afterglows wurde ein Collisional Radiative Modell entwickelt, welches die Reflexion angeregter Spezies an Oberflächen berücksichtigt. Als Diagnostikmethoden wurden die optische Emissionsspektroskopie (OES), die Chemolumineszenz sowie die Langmuir-Sondenmessungen eingesetzt, um die Konzentration metastabil angeregter Spezies zu bestimmen. Es wurde der Einfluß von konstruktiven und äußeren Paramentern auf die Konzentration metastabil angeregter Spezies im Afterglow untersucht. Es zeigt sich, daß unter den gegebenen Bedingungen die Quenching-Stöße der dominierende Verlustprozeß im Afterglow sind. Die Parameter Druck, Strömungsgeschwindigkeit und Länge des Afterglows können zu einem Skalierungsparameter zusammengefaßt werden, der zur online-Prozeßregulierung verwendet werden kann. Es werden

No description available.

Cette thèse étudie le transfert de chaleur par rayonnement observé dans les conditions d'écoulement raréfié, en régime hypersonique qui seraient rencontrés au cours d'une mission d'aérocapture dans l'atmosphère de Titan. Des estimations précises du rayonnement hors-équilibre dans des écoulements à grande vitesse tels que ceux autour des corps de re-entrée, sont indispensables pour la conception de systèmes de protection thermique plus efficace. Parce que la masse du système de protection thermique est une fraction importante de la masse totale du véhicule, il ya un grand intérêt dans la conception de systèmes plus légers et plus efficaces. Les expériences en vol sont coûteuses et contraignantes, c'est pourquoi l'essai en laboratoire dans des installations capables de produire des écoulements hypersoniques est nécessaire. Malheureusement, les échelles de longueur généralement impliquées dans les expériences en vol sont trop grandes pour être testées dans des installations expérimentales et donc des modèles réduits de véhicules 'aeroshells' sont généralement testés. Les tubes d'expansion de l'université de Queensland - X1, X2 et X3 - ont été largement utilisés pour la modélisation à l'échelle réduite des écoulements hypersoniques (Morgan 2001). Pour les installations d'essais au sol telle que la soufflerie X2, une mise à l'échelle binaire est utilisée pour tester des modèles à échelle réduite de véhicules de vol, ce qui constitue le paramètre le plus important à respecter afin de reproduire un vol à haute vitesse. La mise à l'échelle binaire, appelé aussi 'mise à l'échelle 'ƒÏL', exige que le produit de la densité et de la longueur caractéristique du véhicule soit conservé entre le vol et les conditions expérimentales. Toutefois, il a été montré par Capra (2007) que le transfert de chaleur par rayonnement ne suit pas cette même loi de mise à l'échelle, et la similitude n'est pas crée pour les cas en vol où le transfert de chaleur par rayonnement et par convection sont fortement couplés. Cela peut entraîner d'importantes erreurs dans les estimations des propriétés d'écoulement associée et l'estimation du transfert de chaleur due au rayonnement. L'installation X2 a été modifiée en 2006 pour permettre l'expérimentation à basse pression en mode tube à choc non-réfléchi. L'utilisation d'un tube à choc non-réfléchi a permis la mesure du transfert de chaleur par rayonnement à la densité réelle en vol et supprimé les problèmes d'échelle liés à la mesure des rayonnements sur les véhicules en modèle réduit, au moins pour une partie de l'écoulement. Des mesures ont été effectuées dans la région immédiatement située derrière le choc et le long de la ligne médiane de l'écoulement de base, où le choc reste plan. Les écoulements externes, tels que ceux entourant une capsule de re-enntrée, n'ont pas été reproduits. La limite de basse pression d'exploitation était d'environ 10 Pa, limitée par la croissance de la couche limite sur les murs. / This thesis investigates the radiative heat transfer encountered in rarefied, hypervelocity flow conditions such as would be experienced during an aerocapture mission to Titan. Accurate estimates of the nonequilibrium radiation involved in high speed operations such as reentry are essential in order to design these thermal protection systems more efficiently. Because the mass of the thermal protection system is a large fraction of the overall vehicle mass, there is great interest in designing lighter and more efficient systems. Flight experiments are expensive and restrictive, hence laboratory testing is needed in facilities that are capable of producing hypervelocity flow. Unfortunately, as the size of a typical flight vehicle is too large to reasonably test in experimental facilities, subscale models of the aeroshell vehicles are generally tested. The University of Queensland's expansion tube facilities - X1, X2 and X3 - have been widely used for subscale modelling of hypersonic flowfields (Morgan 2001). Ground testing facilities such as the X2 facility take advantage of binary scaling to test small scale models of flight vehicles, which is the most important parameter to match in order to reproduce high speed flight. Binary scaling, also called 'ƒÏL' scaling, requires that the multiplication of density and the characteristic length of the vehicle be balanced between flight and experimental conditions. However, it was shown by Capra (2007) that radiative heat transfer does not follow this same scaling factor, and true similarity with flight is not created for flows where the radiative and convective heat transfer are strongly coupled. This can result in significant errors in the estimates of the associated flow properties and the estimation of the heat transfer due to radiation. The X2 facility was modified in 2006 to allow experimentation at low pressures in nonreflected shock tube mode. Nonreflected shock tube operation allowed the taking of true-flight density measurements of the radiative heat transfer and removed the scaling problems involved in radiation measurements for model vehicles, at least for part of the flowfield. Measurements were made in the region immediately behind the shock along the centreline of the core flow, where the shock remained planar. External flow fields, such as those surrounding a reentry capsule, were not reproduced. The low density operating limit was approximately 10 Pa, limited by boundary layer growth on the walls.

Alors que les applications spatiales prennent une place de plus en plus cruciale dans nos vies, les coûts d'opération des satellites doivent être réduits. Ceci peut être obtenu par l'utilisation de systèmes de propulsion électriques, plus efficients que leurs homologues chimiques traditionnellement utilisés. Une des technologies de propulsion électrique la plus performante et la plus utilisée est le propulseur à effet Hall, toutefois ce système reste complexe et peu compris. En effet de nombreuses questions, concernant le transport anormal des électrons ou les interactions plasma/paroi, sont encore ouvertes.Les réponses à ces questions sont basées sur des mécanismes cinétiques et donc ne peuvent être résolues par des modèles fluides. De plus les caractéristiques géométriques et temporelles de ces mécanismes les rendent difficilement observables expérimentalement. Par conséquent nous avons, pour répondre à ces questions, développé un code cinétique bi-dimensionnel.Grâce à un modèle simplifié de propulseur à effet Hall, nous avons observé l'importance de l'instabilité de dérive électronique pour le transport anormal. Ensuite en utilisant un modèle réaliste de propulseur, nous avons pu étudier les effets des interactions plasma/paroi sur la décharge plasma. Nous avons également pu quantifier les effets intriqués des émissions électroniques secondaires et de l'instabilité de dérive sur le transport anormal. Par une étude paramétrique sur les émissions électroniques secondaires, nous avons pu identifier trois régimes de décharge plasma. Finalement l'impact des ergols alternatifs a pu être étudié en utilisant des processus collisionnels réalistes. / As space applications are increasingly crucial in our daily life, satellite operating costs need to be decreased. This can be achieved through the use of cost efficient electric propulsion systems. One of the most successful and competitive electric propulsion system is the Hall effect thruster, but this system is characterized by its complexity and remains poorly understood. Indeed some key questions, concerning electron anomalous transport or plasma/wall interactions, are still to be answered.Answers to both questions are based on kinetic mechanisms, and thus cannot be solved with fluid models. Furthermore the temporal and geometrical scales of these mechanisms make them difficult to be experimentally measured. Consequently we chose, in order to answer those questions, to develop a bi-dimensional fully kinetic simulation tool.Using a simplified simulation of the Hall effect thruster, we observed the importance of the azimuthal electron drift instability for anomalous cross-field electron transport. Then, using a realistic model of a Hall effect thruster, we were able to study the effects of plasma/wall interactions on the plasma discharge characteristics, as well as to quantify the coupled effects of secondary electron emission and electron drift instability on the anomalous transport. Through parametric study of secondary electron emission, three plasma discharge regimes were identified. Finally the impact of alternative propellants was studied.

No description available.

The quantum interference effects, such as the Autler-Townes (AT) effect and electromagnetically induced transparency (EIT) applied to molecular systems are the focus of this Dissertation in the context of high resolution molecular spectroscopy. We demonstrate that the AT effect can be used to manipulate the spin character of a spin-orbit coupled pair of molecular energy levels serving as a \textit{gateway} between the singlet and triplet electronic states. We demonstrate that the singlet-triplet mixing characters of the \textit{gateway} levels can be controlled by manipulating the coupling laser \textit{E} field amplitude. We observe experimentally the collisional population transfer between electronic states $G^1\Pi_g (v=12, J=21, f)$ and $1^3\Sigma _g^-(v=1, N=21, f)$ of $^7$Li$_2$. We obtain the Stern-Vollmer plot according to the vapor pressure dependence of collisional transfer rate. The triplet fluorescence from the mixed \textit{gateway} levels to the triplet $b^3\Pi_u(v'=1,J'= / Physics