O presente trabalho de mestrado está inserido nos estudos de refração profunda do Projeto Temático 'Estudos Geofísicos e Modelo Tectônico dos Setores Central e Sudeste da Província Tocantins, Brasil Central'. Nesses estudos foram levantadas três linhas de refração de aproximadamente 300 km de extensão, duas no setor Central da Província Tocantins e uma no setor Sudeste, que é o objeto de estudo deste trabalho. Foram utilizados 111 sismógrafos digitais SGR pertencentes ao programa PASSCAL, instrumentos auxiliares do USGS, e 13 sismógrafos digitais e instrumentos auxiliares do IAG/USP. A linha sísmica teve aproximadamente 300 km de extensão com pontos de registro separados a cada 2,5 km, distribuídos ao longo de estradas principais e secundárias. A cada 50 km, aproximadamente, foi realizada uma explosão, nas explosões dos extremos da linha foram utilizados 1000 kg de explosivo e para a explosão central uma carga de 500 kg. Para a determinação das coordenadas geográficas dos pontos de tiro e de registro, foi utilizado o método diferencial com medidas de GPS. O principal objetivo deste trabalho foi obter como produto final um modelo de velocidades sísmicas contendo as características físicas das principais descontinuidades na crosta terrestre e no manto superior. Para análise e processamento dos dados foram utilizados os pacotes SAC, SU, SEIS. Para a modelagem foram utilizados a teoria do raio e a elaboração de sismogramas sintéticos, do pacote SEIS. Para a elaboração do modelo final foram utilizados os dados das explosões dos pontos extremos e central, tendo em vista que devido a problemas técnicos não foram registrados os sinais das outras 4 explosões. Além disso, as explosões registradas não apresentaram sinais claros em toda a extensão da linha. Devido a tudo isso e considerando as unidades geológicas presentes na região de estudo são sugeridos três modelos de velocidades sísmicas. O primeiro modelo refere-se ao tiro direto (EX31) localizado no extremo sudoeste da linha, sobre a Bacia do Paraná. Para este modelo obteve-se para superfície (0 km) a velocidade inicial de 2 km/s (coberturas); para a profundidade de 0,086 km a velocidade inicial é de 5,15 km/s (basalto); para a profundidade de 0,350 km obteve-se a velocidade inicial de 4,6 km/s (arenito - camada de baixa velocidade); para profundidade de 0,650 km a velocidade inicial é de 5,75 km/s e para profundidade de 4 km obteve-se a velocidade inicial de 6,07 km/s. O segundo modelo refere-se ao tiro reverso (EX34) localizado no centro da linha sobre granitóides do Grupo Araxá. Para este modelo obteve -se para superfície (0 km) a velocidade inicial de 2 km/s; para a profundidade de 0,06 km a velocidade inicial é de 5,69 km/s e para a profundidade de 0,860 km obteve-se a velocidade inicial de 6,25 km/s. Finalmente, o terceiro modelo refere-se ao tiro direto para toda a extensão da linha (300 km). Este modelo foi definido a partir de fases secundárias lidas nos registros e modelos anteriores propostos na literatura. Da superfície até os 4 km iniciais de profundidade este modelo é igual ao primeiro, para uma profundidade de 20 km obteve-se a velocidade inicial de 6,70 km/s e para uma profundidade de 40 km a velocidade é de 8,00 km/s (descontinuidade de MOHO). / This work to fulfil the degree of Master of Sciences is inserted among the deep seismic refraction studies of the Thematic Project 'Geophysical Studies and Tectonic Model of the Tocantins Province Central and Southeast Sectors, Central Brazil'. Three refraction lines, of around 300 km long each, were deployed, two of them in the Central sector and the other in the SE sector, that is subject of the present work. The equipment used in this experiment was composed by 111 SGR digital seismographs belonging to the PASSCAL Program. Complemented with auxiliary instruments from USGS and 13 seismographs belonging to IAG/USP. The space among the recording points was 2.5 km, which were located along main and secondary roads. Every 50 km was fired an explosion with 1000 kg of emulsion in each extreme and 500 kg in the central point. The geographical co-ordinates were determined by using the GPS differential method. The main objective of this work is to obtain as a final product a seismic velocity model with the physical characteristics of the main discontinuities in the crust and upper mantle. The packages SAC, SU and SEIS were used to perform the data analysis and processing. To carry on the modelling were used the ray theory and the synthetic seismograms construction, belonging to the SEIS package Data from the extreme and middle points of the seismic line were used to elaborate the final model, considering that due to technical problems signals from the other four explosions were not recorded. Apart from that, the recorded explosions did not present clear signals all along the extension of the line. Due to these facts, and considering also the geological units present in the studied region, are suggested three seismic velocity models. The first model is referred to the direct shot (EX31), which is localised in the Southwest extreme of the line on the Parana Basin province. In this model we obtained the P wave velocity (VP) of 2 km/sec at the surface, corresponding to the unconsolidated sediments and soil on the top of that basin. At a depth of 86 m we found VP of 5,15 km/sec and at a depth of 350 m the velocity VP of 4,6 km/sec, corresponding to the basalt and sand layers of the Parana Basin. Underlying them, at 650 m of depth we found the basement with VP of 5,75 km/sec and finally at a depth of 4 km there is a layer with VP of 6,07 km/sec, corresponding to a typical upper crust P wave velocity. The second model corresponds to the reverse shot (EX34) that is localised in the middle point of the line on the granitoides of the Araxa Group. For this model we obtained VP of 2 km/sec for the superficial layers, then at a depth of 60 m was obtained V P of 5,69 km/sec and for a depth of 860 m the value of V P is 6,25 km/sec. Finally, the third model belongs to the whole line section (300 km) from the direct shot (EX31). This model was obtained by using the arrivals of secondary phases and the results of models proposed in other works. From the surface down to 4 km of depth this model is similar to the first one. At 20 km of depth there is a layer with VP of 6,70 km/sec, corresponding to the lower crust, with Moho at a depth of 40 km with VP of 8,00 km/sec.

Les suspensions qui sont des milieux continus hétérogènes composés d'une phasesolide granulaire et d'une phase liquide, présentent de nombreuses applicationsaux sciences naturelles ou industrielles. La modélisation des phénomènes mis enjeu dans ces applications suggère d'étudier des cas très complexesalors que les cas les plus simples présentent des comportements non-triviauxqui ne sont pas parfaitement compris. C'est pourquoi nous proposons ici des avancées surla modélisation de matériaux modèles, les suspensions de sphères dures mono-disperses.Nous revisitons d'abord la formalisation mathématique du lien entre les modèlescontinus diphasiques et les lois de conservation à l'échelle d'un grain enmoyennant celles-ci sur des volumes élémentaires de référence. Ainsi, nousconstruisons un système de lois de conservation continues. Cependant, ce systèmene peut être résolu numériquement sans l'adjonction de plusieurs hypothèses,nous choisissons alors de nous restreindre aux suspensions non-colloïdalesdans un fluide newtonien. Ainsi, nous proposons un nouveau modèle rhéologiqueintégrant un tenseur de texture, une variable auxiliaire permettant de représenterla déformation du réseau de voisins de chaque particule. Cela nous permetde reproduire quantitativement deux effets mis en évidence par des expériencesde laboratoire. Le premier concerne l'anisotropie que présente la micro-structured'une suspension cisaillée, mesurée par une fonction de distribution de pairesmoyenne. Le second est observé lors d'une inversion brutale de cisaillement,la viscosité apparente de la suspension baisse très rapidement avant de relaxervers un état stationnaire. Ce premier modèle donne un lien au niveau continu entrel'évolution du profil de la fonction de distribution de paires moyenne et l'évolutiond'une quantité macroscopique, la viscosité apparente. Cependant, il ne reproduitpas correctement l'évolution d'autres quantités macroscopiques comme les différencesde contraintes normales. Afin de corriger cela, nous en proposons une extension.Ce nouveau modèle permet d'envisager la modélisation de phénomènes mettant enjeu les différences de contraintes normales et se déroulant sur des échellesde temps plus longues. Ainsi, nous ouvrons la perspective d'améliorer la prédictiondes phénomènes de migration qui se traduisent par le fait que les particules nesuivent pas exactement les lignes de courant, par exemple celles-ci fuientles zones les plus cisaillées. En effet, les différences de contraintes normalesjouent un rôle important dans la dynamique de la phase granulaire. Cela suggèred'intégrer notre nouvelle rhéologie dans le système de lois de conservation quenous avions proposé. Nous transformons ensuite ce système en un problème intégrant deux vitesses,celle du mélange et celle de la phase granulaire. L'originalité de notre contributionréside dans l'introduction d'une contrainte unilatérale dans un modèle de suspension.Cela permet de modéliser au niveau continu le contact entre deux sphèresdures qui ne peuvent pas s'inter-pénétrer. Nous obtenons un problème pouvant s'interprétercomme un couplage entre deux sous-systèmes. Le premier sous-système ressemble à un modèle defluide visco-élastique, le second est un système compressible visqueux congestionné,comme ceux utilisés pour modéliser des mouvements de foule. / Suspensions which are heterogeneous continuous media composed by a solid granular phaseand a liquid phase present many applications from natural and industrial sciences.Modelling the phenomenon involved in those applications suggests studyingvery complex cases whereas the simplest one present non trivial behaviour that are notperfectly understood. This is why we put forward some progresses in the understanding ofa reference material, mono-disperse suspension of hard spheres. Firstly we compute averagedversions of conservation laws at the scale of the grain. Hence we get continuous quantities atthe scale of an elementary reference volume and it allows us to revisit mathematical buildingof continuous biphasic models. Hence, we provide a system of continuous conservation laws.Nevertheless, we have to add several hypothesis to get a well posedmathematical problem from our system. With that mind, we choose to focus on non-colloidalsuspensions with a Newtonian suspending fluid. Thus, we propose a new rheological modelincluding a texture tensor which is an ancillary variable modelling the average deformationof the local cages formed by neighbouring particles. Hence, we can quantitatively reproducetwo effects that have been experimentally measured. The first one is about the anisotropy ofthe microstructure in a sheared suspension, measured by the averaged pair distribution function.The second one is the evolution of apparent viscosity that drops brutally before relaxing to asteady state during a shear-reversal experiment. This first model provides a link between twocontinuous quantities, the averaged pair distribution function and the apparent viscosity.However, it reproduces badly the evolution of some macroscopic quantities, the normal stressdifferences. This is why we extend our first model, improving those bad predictions. On largertime scales, it has been observed that the particles do not follow strictly the flow lines,for instance, they leave sheared zones. This phenomenon is called migration. Our extendedrheological model allows to enhance migration phenomenon predictions because normal stressdifferences play a crucial role in granular phase motion. In that mind, we integrate ournew rheology in the system of conservation laws that we stated in the beginning, then, weprocess it into a new mathematical problem.We put forward a system including both a bulk velocity and a granular phase one.We introduce an unilateral constraint in order to model the inelastic contact interactionbetween two rigid spheres at the macroscopic level. It constitutes the originality of ourproposal. Finally, we get a problem that interprets as two coupled sub-problems.The first one is like a visco-elastic fluid model and the second one is a compressiblecongested viscous system, like those used to modelcrowd motions.

Le modèle de concordance de la cosmologie moderne repose entre autre sur l'existence de matière dite « noire », matière qui n'intéragirait que gravitationellement et qui ne peut donc pas être observée directement. Les vitesses particulières des galaxies, puisqu'elles tracent le champ de gravité, sont des sondes non-biaisées de la matière dans l'Univers. Ainsi, l'étude de ces vitesses particulières permet non seulement de cartographier l'Univers proche (matière noire comprise), mais aussi de tester le modèle ΛCDM via la vitesse d'expansion de l'Univers et le taux de formation des structures. Observationnellement, la mesure de la vitesse particulière d'une galaxie se fait à partir de la mesure de sa distance, mesure très imprécise pour les données extragalactiques. Mal modélisée, cette incertitude conduit à des analyses biaisées des vitesses particulières, et ainsi détériore la qualité de cette sonde cosmologique. Dans ce contexte, cette thèse s'intéresse aux erreurs systématiques statistiques des analyses de vitesses particulières. D'abord en étudiant puis modélisant ces erreurs systématiques. Ensuite en proposant de nouveaux modèles pour les prendre en compte. En particulier, y est développé un modèle permettant, à partir des mesures de la vitesse de rotation des galaxies, de reconstruire le champ de densité de l'Univers Local. Ce modèle s'appuie sur l'analyse des corrélations de vitesse données par le modèle de concordance, et la modélisation de la relation de Tully-Fisher, qui lie la vitesse de rotation des galaxies à leur luminosté. Le modèle développé est appliqué au catalogue de distances extragalactiques CosmicFlows-3, permettant ainsi une nouvelle cartographie de l'Univers proche et de sa cinématique / The cosmological concordance model relies on the existence of a ≪ dark ≫ matter which hypothetically only interacts through gravity. Hence, the dark matter could not be observed directly with standard techniques. Since they directly probe gravity, peculiar velocities of galaxies are an unbiased tool to probe the matter content of the Universe. They can trace the total matter field and constrain the Local Universe’s expansion rate and growth of structures. The peculiar velocity of a galaxy can only be measured from its distance, which determination is very inaccurate for distant objects. If not correctly modeled, these uncertainties can lead to biaised analyses and poor constraints on the ΛCDM model. Within this context, this PhD studies the systematic and statistical errors of peculiar velocity analyses. First by investigating and modeling these errors. Then by building Bayesian models to include them. In particular, a model of the Local Universe’s velocity field from the observations of the rotational velocity of galaxies is presented. This model relies on the ΛCDM’s peculiar velocity correlations and on a Tully-Fisher relation model. The model has then been applied to the CosmicFlows-3 catalog of distances and provides a new kinematic map of the Local Universe

Flows, instabilities, and magnetism play significant roles in the internal and atmospheric dynamics of objects ranging from the smallest exoplanets to the largest stars. These phenomena are governed by the equations of magnetohydrodynamics (MHD), which link the flows and magnetic fields, and from which the operational parameters and growth rates of instabilities can be recovered. Here we present an overview of interesting phenomena (such as the internal dynamics of stellar and planetary objects, as well as instabilities which might operate within these environs), as well as computational techniques by which these phenomena might both be understood and analysed (through both ‘simplifications’ of the MHD equations and different numerical/computational approaches). We first present an investigation into the Heat-Flux-Driven Buoyancy Instability (HBI) within stellar and planetary atmospheres, considering both the parameter space it might operate within as well as its non-linear effects during said operation. We find that whilst the HBI may be able to play a role in Solar, stellar and planetary atmospheres, it is likely to be quite limited in scope, only operating within small regions. However, its dramatic consequences for heat transport in the non-linearly evolved state, and the prospects that it may operate outside the narrow regimes that our analytical analysis suggested, suggest that it may merit further study. This is followed with a discussion of a method by which the surface flows of exoplanets might be measured: The Rossiter-Mclaughlin Effect at Secondary Eclipse (RMse). We formulate the effect, showing that the formalism is identical to the traditional Rossiter-Mclaughlin effect, albeit in a different frame (a planet transiting a star becomes a star transiting a planet), and consider its observational implications: the effect should be observable for the brightest planet hosting stars using upcoming 40m-class telescopes (i.e.E-ELT). We finish with a series of 3D anelastic simulations of fully convective stars, designed to investigate how the internal flows are affected by varying stellar parameters, as well as a possible link between residual entropy and differential rotation contours, and a method by which this link can be used (via the thermal wind equation - TWE) to extrapolate the internal rotation. We find a clear transition between ‘solar-like’ and ‘anti-solar’ internal dynamics, characterised in the meridional circulation, differential rotation, residual entropy, and angular momentum flux profiles. Furthermore we find that, whilst the alignment between residual entropy and differential rotation contours is somewhat varied, the resultant extrapolation, via the TWE, produces a generally good fit to the differential rotation contours, suggesting a general robustness to the theory.

This dissertation describes a new detailed abundance study of field red horizontal branch stars, RR Lyrae stars and blue horizontal branch stars. To carry out this study, we obtained high-resolution and high signal-to-noise ratio echelle spectra at the McDonald observatory and Las Campanas Observatory. In addition, new pulsational emphemerides were derived to analyze the spectra of RR Lyrae stars throughout the pulsational cycles. We find that the abundance ratios are generally consistent with those of field stars of similar metallicity in different evolutionary stages and throughout the pulsational cycles for RR Lyrae stars. We also estimated the red and blue edges of the RR Lyrae instability strip using the derived effective temperatures of RHB and BHB stars. New variations between microturbulence and effective temperature are found among the HB population. For the first time the variation of microturbulence as a function of phase is empirically shown to be similar to the theoretical calculations. Finally, through the study of a rare eclipsing sdB and M dwarf binary, we discovered an unusually low mass for this type of HB star, which observationally proved the existence of a new group of low-mass sdB stars that was theoretically predicted in the past. / text

Black shales are sedimentary rocks with a high content of organic carbon, which leads to a dark grayish to black color. Due to their potential to contain oil or gas, black shales are of great interest for the support of the worldwide energy supply. An integrated seismic investigation of the Lower Palaeozoic black shales was carried out at the Danish island Bornholm to locate the shallow-lying Alum Shale layer and its surrounding formations and to characterize its potential as a source rock. Therefore, two seismic experiments at a total of three crossing profiles were carried out in October 2010 and in June 2012 in the southern part of the island. Two different active measurements were conducted with either a weight drop source or a minivibrator. Additionally, the ambient noise field was recorded at the study location over a time interval of about one day, and also a laboratory analysis of borehole samples was carried out. The seismic profiles were positioned as close as possible to two scientific boreholes which were used for comparative purposes. The seismic field data was analyzed with traveltime tomography, surface wave inversion and seismic interferometry to obtain the P-wave and S-wave velocity models of the subsurface. The P-wave velocity models which were determined for all three profiles clearly locate the Alum Shale layer between the Komstad Limestone layer on top and the Læså Sandstone Formation at the base of the models. The black shale layer has P-wave velocities around 3 km/s which are lower compared to the adjacent formations. Due to a very good agreement of the sonic log and the vertical velocity profiles of the two seismic lines, which are directly crossing the borehole where the sonic log was conducted, the reliability of the traveltime tomography is proven. A correlation of the seismic velocities with the content of organic carbon is an important task for the characterization of the reservoir properties of a black shale formation. It is not possible without calibration but in combination with a full 2D tomographic image of the subsurface it gives the subsurface distribution of the organic material. The S-wave model obtained with surface wave inversion of the vibroseis data of one of the profiles images the Alum Shale layer also very well with S-wave velocities around 2 km/s. Although individual 1D velocity models for each of the source positions were determined, the subsurface S-wave velocity distribution is very uniform with a good match between the single models. A really new approach described here is the application of seismic interferometry to a really small study area and a quite short time interval. Also new is the selective procedure of only using time windows with the best crosscorrelation signals to achieve the final interferograms. Due to the small scale of the interferometry even P-wave signals can be observed in the final crosscorrelations. In the laboratory measurements the seismic body waves were recorded for different pressure and temperature stages. Therefore, samples of different depths of the Alum Shale were available from one of the scientific boreholes at the study location. The measured velocities have a high variance with changing pressure or temperature. Recordings with wave propagation both parallel and perpendicular to the bedding of the samples reveal a great amount of anisotropy for the P-wave velocity, whereas the S-wave velocity is almost independent of the wave direction. The calculated velocity ratio is also highly anisotropic with very low values for the perpendicular samples and very high values for the parallel ones. Interestingly, the laboratory velocities of the perpendicular samples are comparable to the velocities of the field experiments indicating that the field measurements are sensitive to wave propagation in vertical direction. The velocity ratio is also calculated with the P-wave and S-wave velocity models of the field experiments. Again, the Alum Shale can be clearly separated from the adjacent formations because it shows overall very low vP/vS ratios around 1.4. The very low velocity ratio indicates the content of gas in the black shale formation. With the combination of all the different methods described here, a comprehensive interpretation of the seismic response of the black shale layer can be made and the hydrocarbon source rock potential can be estimated. / Schwarzschiefer sind Sedimentgesteine, die einen hohen Gehalt an organischem Kohlenstoff aufweisen, was zu einer dunkelgrauen bis schwarzen Färbung führt. Da Schwarzschiefer das Potenzial besitzen, Öl oder Gas zu enthalten und somit zur weltweiten Energieversorgung beitragen könnten, sind sie von großem Interesse. Mit Hilfe der Kombination verschiedener seismischer Messverfahren wurden die Schwarzschiefer des Unteren Paläozoikums auf der dänischen Insel Bornholm untersucht um den oberflächennahen Alaunschiefer und dessen Umgebungsgestein dort zu lokalisieren und sein Potenzial als Muttergestein abzuschätzen. Dafür wurden im Oktober 2010 und im Juni 2012 im südlichen Teil der Insel zwei seismische Experimente auf insgesamt drei sich kreuzenden Profilen durchgeführt. Für zwei aktive seismische Messungen wurden ein Fallgewicht und ein Minivibrator als Quellen genutzt. Zusätzlich wurde im Messgebiet noch das Wellenfeld des umgebenden Rauschens über einen Zeitraum von etwa einem Tag aufgezeichnet. Außerdem wurden Labormessungen an Bohrkernen aus dem Alaunschiefer durchgeführt. Die seismischen Messprofile befanden sich so nah wie möglich an zwei wissenschaftlichen Bohrungen, die für Vergleichszwecke genutzt wurden. Um die P- und S-Wellengeschwindigkeitsmodelle des Untergrundes zu erhalten wurden die seismischen Felddaten mittels Laufzeittomographie, Oberflächenwelleninversion und seismischer Interferometrie ausgewertet. Die P-Wellenmodelle, die für alle drei seismischen Profile erstellt wurden, zeigen den Alaunschiefer zwischen dem Komstad Kalkstein, der den Alaunschiefer überdeckt, und der Læså Sandsteinformation, die die Basis der Modelle bildet. Für die Schwarzschieferschicht ergeben sich mit rund 3 km/s deutlich geringere P-Wellengeschwindigkeiten als für die umgebenden Gesteine. Zwei seismische Profile liegen direkt an einer der Bohrungen, für die verschiedene Bohrloch-Logs durchgeführt wurden. Der Vergleich des Sonic-Logs mit den vertikalen Geschwindigkeitsprofilen beider Modelle am Bohrpunkt zeigt eine sehr gute übereinstimmung aller Geschwindigkeiten. Dies ist ein Indiz für die Plausibilität der durchgeführten Laufzeittomographie. Um die Reservoireigenschaften der Schwarzschieferschicht einordnen zu können, wurde versucht, die seismischen Geschwindigkeiten mit dem Gehalt an organischem Material zu korrelieren. Ohne geeignete Kalibrierung ist diese Korrelation schwierig, kann aber mit Hilfe der Tomographieergebnisse ein zweidimensionales Abbild der Verteilung des organischen Materials im Untergrund liefern. Auch das S-Wellengeschwindigkeitsmodell, welches mit der Oberflächenwelleninversion der Vibroseisdaten erstellt wurde, bildet den Alaunschiefer gut ab. Hierbei zeigen sich S-Wellengeschwindigkeiten um 2 km/s. Obwohl jeweils nur 1D-Modelle für jede Quellposition bestimmt wurden, ergibt sich für die gesamte Untergrundstruktur des untersuchten Profils ein einheitliches Bild der Geschwindigkeiten. Einen sehr neuen Ansatz bildet die Anwendung der seismischen Interferometrie auf ein sehr kleines Untersuchungsgebiet und über einen sehr kurzen Zeitraum. Neu ist außerdem, dass für die Bestimmung der endgültigen Interferogramme nur Zeitfenster der Kreuzkorrelationen ausgewählt werden, in denen die Signalqualität hinreichend gut ist. In den berechneten Kreuzkorrelationen sind sogar P-Wellen enthalten, was auf die geringen Abstände der seismischen Rekorder zurück zu führen ist. Bei den Labormessungen wurden die Raumwellen für verschiedene Drücke und Temperaturen aufgezeichnet. Die Messungen der Geschwindigkeiten sowohl parallel als auch senkrecht zur Schichtung der Proben zeigen eine starke Anisotropie für die P-Welle. Dagegen scheint die S-Wellengeschwindigkeit fast unabhängig von der Ausbreitungsrichtung der Wellen zu sein. Auch das Verhältnis der Geschwindigkeiten weist starke Anisotropie auf. Für die Wellenausbreitung senkrecht zur Schichtung zeigen sich sehr niedrige Werte, die Werte für die Messungen parallel zur Schichtung sind dagegen deutlich erhöht. Ein interessanter Aspekt der aus den Labormessungen resultiert ist, dass die Geschwindigkeit der Messungen senkrecht zur Schichtung mit den Geschwindigkeitswerten der Feldmessungen übereinstimmen. Damit scheinen die Feldmessungen besonders die Ausbreitung der Wellen in vertikaler Richtung zu registrieren. Das Geschwindigkeitsverhältnis wurde auch mit den P- und S-Wellenmodellen der Feldexperimente berechnet. Auch hier hebt sich der Alaunschiefer mit deutlich verringerten Werten um 1.4 vom Umgebungsgestein ab. Solch geringe Werte für das Verhältnis der Geschwindigkeiten deutet auf den Gehalt von Gas im Schwarzschiefer. Mit der Kombination der verschiedenen Methoden ist es möglich, die seismische Antwort der Schwarzschieferschicht umfassend zu beschreiben und Schlussfolgerungen darüber zu ziehen, ob die hier untersuchte Schwarzschieferschicht das Potenzial hat als Kohlenwasserstofflagerstätte zu fungieren.

Depuis la première détection d'une planète extrasolaire autour d'une étoile de type solaire par Mayor et Queloz (1995), plus de 1500 planètes ont été découverts. Actuellement il existe un énorme intérêt à découvrir et caractériser des planètes semblables à la Terre, en particulier celles situées dans la zone habitable de leur étoile hôte (définie comme la distance à l'étoile hôte où la température de la planète permet l'existence d'eau liquide à la surface). La détection de planètes de type terrestre, et la recherche de biomarqueurs dans leurs atmosphères sont parmi les principaux objectifs de l'astronomie du vingt et unième siècle. La méthode des vitesses radiales (VR), consistant à mesurer le mouvement réflexe de l'étoile induit par des planètes en orbite, est une remarquable technique pour atteindre cet objectif.Pour atteindre les précisions nécessaire à la detection de telles planètes il est absolument nécessaire de concevoir des spectrographes extrêmement stables, d'avoir une très bonne compréhension de l'activité stellaire (qui peut mimer l'effet d'une planète), d'effectuer un traitement soigneux de l'atmosphère terrestre (laquelle inévitablement laisse des empreintes dans les spectres acquis depuis le sol), et de disposer d'une puissante technique pour extraire, à partir des spectres, autant d'information Doppler que possible. La recherche de planètes orbitant autour des étoiles de très faible masse, plutôt qu'autour des étoiles de type solaire, permet d'aborder dès maintenant la détection de planètes de faible masse dans la zone habitable. En effet, en gardant tout les autres paramètres égaux, le mouvement réflexe (et donc l'amplitude de la variation VR) sera plus grande si l'étoile centrale est de très faible masse. De plus les naines M ont une plus faible luminosité que les étoiles de type solaire, il en resulte des périodes orbitales courtes des planètes dans la zone habitable (~50 jours pour les naines M contre ~360 jours pour des étoiles de type solaire), entraînant à nouveau en une plus grande amplitude des VR. Une précision de ~1 m/s en VR permet la détection d'une planète dans la zone habitable d'une naine M, alors que ~0.1 m/s sont nécessaire dans le cas d'une étoile de type solaire.Cette thèse vise à optimiser l'extraction de VR des spectres des naines M à haute résolution acquis avec le spectrographe HARPS (avec une possibilité d'applications futures sur d'autres instruments comme SOPHIE, HARPS-N et le prochain spectrographe infrarouge SPIRou - prochainement mis en service au CFHT). Les effets de l'activité stellaire des naines M seront également analysées, dans le contexte de la technique des VR. Divers traceurs d'activité stellaire sont utilisés pour rejeter des fausses détections ou pour étudier les relations entre l'activité magnétique et la rotation. Dans cette thèse (Chap. 3) je calibre pour la première fois le flux dans les raies H et K du Calcium en fonction de la luminosité bolométrique et je détermine la relation entre cet estimateur R'HK et la période de rotation des naines M. Dans le chapitre 4 je décris l'implémentation d'une méthode d'extraction de VR par une minimisation du Chi-deux entre un template spectral et les spectres observés. Je démontre que cette méthode est plus précise que celle classiquement utilisée. Les raies telluriques qui affectent les mesures VR sont prises en compte dans les procédures d'analyse. Ces méthodes sont testées sur des systèmes avec des candidats planétaires, je discuterais l'analyse de certains de ces systèmes. / Since the first detection of an extrasolar planet orbiting a Sun-like star by Mayor and Queloz (1995), more than 1500 have been discovered. Enormous interest is currently focused on finding and characterising Earth-like planets, in particular those located in the habitable zone of their host star (defined as the distance from the host star where the planet temperature allows liquid water to flow on its surface). Both the detection of Earth-like planets, and the search for biomarkers in their atmospheres are among the main objectives of the twenty-first century's astronomy. The method known as radial velocities (RV), that consists in the measure of the star's reflex motion induced by orbiting planets, is a promising technique to achieve that quest.The main difficulties with the RV technique are the needs of an extremely stable spectrograph, a correct understanding of stellar activity (which can mimic the effect of a planet), a careful treatment of our Earth's atmosphere (which inevitable imprints spectra taken from the ground), and the need to dispose of a powerful algorithm to extract as much Doppler information as possible from the recorded spectra. Search for planets orbiting very low-mass stars (M dwarfs) can more easily reach the goal of detecting low-mass planets in the habitable zone of their parent star, compared to solar-type stars. Indeed, everything else being equal, a lower mass of the host star implies a larger reflex motion, and thus a larger RV amplitude. Moreover, the lower luminosity of M dwarfs compared to Sun-like stars, implies shorter orbital periods from planets in the habitable zone (~50 days against ~360 days, for M dwarfs compared to solar-type stars, respectively), resulting again in a larger RV amplitude. A RV precision of ~1 m/s allows a planet detection in the habitable zone of an M dwarf, whereas ~0.1 m/s is required in the case of a solar-type stars.This thesis aims to optimise the RV extraction from HARPS high-resolution spectra (and to open similar analysis on other instruments like SOPHIE, HARPS-N and the upcoming infrared spectrograph SPIRou -- to be commissioned to the 3.6-m CFH-Telescope). The effects of stellar activity will also be analysed, and contextualised in the RV technique. Stellar activity tracers are used to reject false detections or to study the relationships between the stellar magnetic activity and rotation. In this thesis (Chap.ref{chap:mag_activity}) I calibrate for the first time the ratio between the Ca textrm{small II} Htextrm{small &}K chromospheric lines and the bolometric luminosity for M dwarfs. I determine a relationship between the R^prime_{HK}-index and the rotation period of M dwarfs. In chapter~ref{chap:template_matching} I describe my algorithm to extract RVs through a chi^2-minimisation between a stellar template and the observed spectra. I demonstrate the improved accuracy of this method. Telluric spectral lines also affect the measurements of RV and are taken into account in the analysis procedures. I tested these methods on systems with planetary candidates, and for some systems, I took in charge the Keplerian analysis.

Made available in DSpace on 2014-06-11T19:24:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-08Bitstream added on 2014-06-13T18:52:23Z : No. of bitstreams: 1 silva_mc_me_botfca.pdf: 1187348 bytes, checksum: b926169213d8acbaf9358f1d270ff76d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Na operação de semeadura, o estande adequado e a uniformidade de distribuição de sementes são componentes de grande influência na produtividade do milho. Esses fatores podem ser afetados por inúmeras variáveis, sendo a velocidade de operação da semeadora-adubadora uma das mais importantes, além da adequação semente/orifício no disco dosador. A velocidade de deslocamento e a regulagem da semeadora, sendo inadequadas, podem proporcionar baixa população de plantas, acarretando em uma produtividade não desejada. O presente trabalho teve como objetivo analisar o desempenho operacional de uma semeadora-adubadora de precisão, em função de cinco velocidades de deslocamento e dois tipos de martelete, utilizada para a semeadura da cultura do milho em sistema plantio direto. O experimento foi instalado e conduzido em área experimental pertencente à Faculdade de Ciências Agronômicas, UNESP – Botucatu, SP, no período de dezembro de 2007 a maio de 2008. O solo da área experimental foi classificado como Nitossolo Vermelho Distroférrico, textura muito argilosa. O delineamento experimental utilizado foi de blocos ao acaso, com parcelas subdivididas, em esquema fatorial 2x5, sendo dois tipos de marteletes (4 e 5 dentes) e cinco velocidades de deslocamento (3,0; 4,5; 5,0; 7,0 e 9,0 km h-1) com quatro repetições. Assim, o experimento teve 10 tratamentos, totalizando 40 parcelas experimentais. Foram avaliados os dados referentes à porcentagem de cobertura do solo, profundidade do sulco de semeadura, área de solo mobilizado e de deposição de sementes, consumo horário e operacional de combustível, força na barra de tração do trator, velocidade de deslocamento, capacidade de campo efetiva, distribuição longitudinal de sementes, número médio de dias para emergência de plântulas, componentes morfológicos e componentes de produção da planta de milho, danos mecânicos nas... / In the sowing operation, the appropriate stand and the uniformity on the distribution of seeds are mentioned as factors of great influence on the corn yield.. These factors can be affected by several variables, being the planter displacement velocity one of the most important of them, besides the adjustment of seeds in the perforated disc device for seed dosage. The inadequate displacement velocity and adjustment of the planter may provide low population of plants, leading to an undesired yield. The current paper had as its objective to analyze the precision planter’s operational and energetically performances according to five different displacement velocities and two types of jumpers used for planting no-tillage corn.The experiment was installed and conducted at the experimental area belonging to the College of Agricultural Science - UNESP located in Botucatu, Sao Paulo state, in the period comprised between December, 2007 and May, 2008. The experimental soil area was classified as Nitossolo Vermelho Distroférrico presenting a deep argillaceous texture. The experimental design consisted of blocks at random with parcels subdivided in factorial scheme 2x5, two types of jumpers (4 and 5 staples) and 5 different displacement velocities (3,0; 4,5; 5,0; 7,0 e 9,0 Km h-1) with four repetitions. Thus, the experiment was composed by 10 treatments, totalizing 40 experimental plots. The evaluated data regarded to the percentage of soil coverage, the sowing line depth, mobilized soil and seed overthrown area, horal and operational fuel consumption, force on the tractor traction bar, displacement velocity, effective field capacity, longitudinal distribution of seeds, average number of days for the emergence of seedlings, morphological and corn production components, mechanical harm on seeds and grain production. The displacement velocity effect was verified on the following variables: horal... (Complete abstract click electronic access below)

O presente trabalho de mestrado está inserido nos estudos de refração profunda do Projeto Temático 'Estudos Geofísicos e Modelo Tectônico dos Setores Central e Sudeste da Província Tocantins, Brasil Central'. Nesses estudos foram levantadas três linhas de refração de aproximadamente 300 km de extensão, duas no setor Central da Província Tocantins e uma no setor Sudeste, que é o objeto de estudo deste trabalho. Foram utilizados 111 sismógrafos digitais SGR pertencentes ao programa PASSCAL, instrumentos auxiliares do USGS, e 13 sismógrafos digitais e instrumentos auxiliares do IAG/USP. A linha sísmica teve aproximadamente 300 km de extensão com pontos de registro separados a cada 2,5 km, distribuídos ao longo de estradas principais e secundárias. A cada 50 km, aproximadamente, foi realizada uma explosão, nas explosões dos extremos da linha foram utilizados 1000 kg de explosivo e para a explosão central uma carga de 500 kg. Para a determinação das coordenadas geográficas dos pontos de tiro e de registro, foi utilizado o método diferencial com medidas de GPS. O principal objetivo deste trabalho foi obter como produto final um modelo de velocidades sísmicas contendo as características físicas das principais descontinuidades na crosta terrestre e no manto superior. Para análise e processamento dos dados foram utilizados os pacotes SAC, SU, SEIS. Para a modelagem foram utilizados a teoria do raio e a elaboração de sismogramas sintéticos, do pacote SEIS. Para a elaboração do modelo final foram utilizados os dados das explosões dos pontos extremos e central, tendo em vista que devido a problemas técnicos não foram registrados os sinais das outras 4 explosões. Além disso, as explosões registradas não apresentaram sinais claros em toda a extensão da linha. Devido a tudo isso e considerando as unidades geológicas presentes na região de estudo são sugeridos três modelos de velocidades sísmicas. O primeiro modelo refere-se ao tiro direto (EX31) localizado no extremo sudoeste da linha, sobre a Bacia do Paraná. Para este modelo obteve-se para superfície (0 km) a velocidade inicial de 2 km/s (coberturas); para a profundidade de 0,086 km a velocidade inicial é de 5,15 km/s (basalto); para a profundidade de 0,350 km obteve-se a velocidade inicial de 4,6 km/s (arenito - camada de baixa velocidade); para profundidade de 0,650 km a velocidade inicial é de 5,75 km/s e para profundidade de 4 km obteve-se a velocidade inicial de 6,07 km/s. O segundo modelo refere-se ao tiro reverso (EX34) localizado no centro da linha sobre granitóides do Grupo Araxá. Para este modelo obteve -se para superfície (0 km) a velocidade inicial de 2 km/s; para a profundidade de 0,06 km a velocidade inicial é de 5,69 km/s e para a profundidade de 0,860 km obteve-se a velocidade inicial de 6,25 km/s. Finalmente, o terceiro modelo refere-se ao tiro direto para toda a extensão da linha (300 km). Este modelo foi definido a partir de fases secundárias lidas nos registros e modelos anteriores propostos na literatura. Da superfície até os 4 km iniciais de profundidade este modelo é igual ao primeiro, para uma profundidade de 20 km obteve-se a velocidade inicial de 6,70 km/s e para uma profundidade de 40 km a velocidade é de 8,00 km/s (descontinuidade de MOHO). / This work to fulfil the degree of Master of Sciences is inserted among the deep seismic refraction studies of the Thematic Project 'Geophysical Studies and Tectonic Model of the Tocantins Province Central and Southeast Sectors, Central Brazil'. Three refraction lines, of around 300 km long each, were deployed, two of them in the Central sector and the other in the SE sector, that is subject of the present work. The equipment used in this experiment was composed by 111 SGR digital seismographs belonging to the PASSCAL Program. Complemented with auxiliary instruments from USGS and 13 seismographs belonging to IAG/USP. The space among the recording points was 2.5 km, which were located along main and secondary roads. Every 50 km was fired an explosion with 1000 kg of emulsion in each extreme and 500 kg in the central point. The geographical co-ordinates were determined by using the GPS differential method. The main objective of this work is to obtain as a final product a seismic velocity model with the physical characteristics of the main discontinuities in the crust and upper mantle. The packages SAC, SU and SEIS were used to perform the data analysis and processing. To carry on the modelling were used the ray theory and the synthetic seismograms construction, belonging to the SEIS package Data from the extreme and middle points of the seismic line were used to elaborate the final model, considering that due to technical problems signals from the other four explosions were not recorded. Apart from that, the recorded explosions did not present clear signals all along the extension of the line. Due to these facts, and considering also the geological units present in the studied region, are suggested three seismic velocity models. The first model is referred to the direct shot (EX31), which is localised in the Southwest extreme of the line on the Parana Basin province. In this model we obtained the P wave velocity (VP) of 2 km/sec at the surface, corresponding to the unconsolidated sediments and soil on the top of that basin. At a depth of 86 m we found VP of 5,15 km/sec and at a depth of 350 m the velocity VP of 4,6 km/sec, corresponding to the basalt and sand layers of the Parana Basin. Underlying them, at 650 m of depth we found the basement with VP of 5,75 km/sec and finally at a depth of 4 km there is a layer with VP of 6,07 km/sec, corresponding to a typical upper crust P wave velocity. The second model corresponds to the reverse shot (EX34) that is localised in the middle point of the line on the granitoides of the Araxa Group. For this model we obtained VP of 2 km/sec for the superficial layers, then at a depth of 60 m was obtained V P of 5,69 km/sec and for a depth of 860 m the value of V P is 6,25 km/sec. Finally, the third model belongs to the whole line section (300 km) from the direct shot (EX31). This model was obtained by using the arrivals of secondary phases and the results of models proposed in other works. From the surface down to 4 km of depth this model is similar to the first one. At 20 km of depth there is a layer with VP of 6,70 km/sec, corresponding to the lower crust, with Moho at a depth of 40 km with VP of 8,00 km/sec.

This thesis deals with propagation of pressure and flow pulsations, which are strongly affected by the tube flexibility. There are two mathematic models introduced, which are derived from basic physical relations. First model assumes velocity only in the axis direction. Second one assumes also non-zero radial velocity. Kelvin-Voigt model for viscoelasticity was used. Furthermore, experimental measurement was designed and evaluated. Measured data was used to calculate material properties. In addition, dynamic transfer was determined.