Sliding isolation bearings are used widely around the world to minimize damage to structures and their contents during earthquakes. Past studies have typically focused on the behavior of sliding isolation bearing under design conditions; however, as the performance-based earthquake engineering advances, it is necessary and critical to understand the ultimate or even failure behavior, of structural systems under extreme conditions. Using a double friction pendulum bearing with non-articulated slider as an example, this thesis comprehensively investigates the extreme behavior of the sliding bearing components as well as steel frame buildings isolated using these bearings. This thesis is comprised of two major parts. The first includes numerical and experimental studies of double friction pendulum bearings at the component-level. Finite element investigation shows that depending on the superstructure mass there are two major failure modes for the double friction pendulum bearings. When the superstructure mass is sufficiently large, the failure mode is dominated by the restraining rim yielding; however, when the mass is relatively small, its failure mode shifts to bearing uplift. A simplified analytical model which can directly simulate the impact and uplift behavior of double friction pendulum bearing is also implemented, comparing well to the finite element analysis. Then, to validate the ability of the models to predict extreme behavior as well as to investigate the effect of the restraining rim design, which varies around the world, an experimental study was carried out. Uplift behavior and significant rim yielding were observed during the shake table tests. Moreover, other response parameters, including uplift and shear forces, are evaluated and compared among different rim designs. It is found the restraining rim design has a substantial influence on the bearing’s extreme behavior. The second part of the thesis investigates the system-level behavior of steel frame buildings isolated with double friction pendulum bearings. It is found that the stiffness of the superstructure largely dictates the system-level failure modes and collapse probability. Initially, bearings with rigid restraining rims are investigated. For flexible moment-resisting frames, the system-level failure modes are mixed: both the bearing uplift and superstructure yielding contribute; also, using current code-minimum design results in acceptably low probability of collapse. However, for stiff concentrically-braced frames, the impact force can impose large ductility demands on the superstructure regardless of its strength. As a result, the system-level failure comes exclusively from superstructure yielding, and only by increasing bearing’s displacement capacity beyond the minimum code allowed can the design meet as acceptably low collapse probability. When flat rims are used instead for the bearing design, the failure modes for both building types are exclusively bearing failure. Furthermore, while it is more apparent for concentrically-braced frames, using flat rims for the bearings can reduce the collapse probability compared to using rigid rims. / Thesis / Doctor of Philosophy (PhD)

[ES] La inyección de combustible es, entre los temas de investigación de motores, una de las piezas críticas para obtener un motor eficiente. El papel es aún más significativo cuando se persigue una estrategia de inyección directa. La geometría interna y el movimiento de la aguja determinan el comportamiento del flujo del inyector, que se sabe que afecta enormemente al desarrollo externo del spray y, en última instancia, al rendimiento de la combustión dentro de la cámara. La conciencia sobre el cambio climático y los contaminantes ha ido creciendo, impulsando el esfuerzo en motores más limpios. En este sentido, los motores de gasolina tienen un margen más amplio para mejo- rar que los motores diesel. La evolución de los antiguos PFI a las modernas estrategias de inyección directa, que se utilizan en los motores de nueva generación, demuestra esta tendencia. Los sistemas GDI tienen el potencial de cumplir con las estrictas emisiones y aumentar el ahorro de combustible, sin embargo, todavía se enfrenta a muchos desafíos. Este trabajo implica el uso de dos inyectores, uno es una moderna tobera de GDI de investigación designada por el Engine Combustion Network (ECN), y el otro es una unidad de inyección de producción (PIU) con la misma tecnología y una geometría ligeramente diferente. Ambos equipos se someten a una completa caracterización (flujo interno y externo) que abarca las técnicas más avanzadas en diversas instalaciones experimentales. Además, se diseña y construye una nueva instalación para realizar experimentos en condiciones de evaporación instantánea (cuando la presión de vapor del combustible inyectado es superior a la presión del volumen de descarga). La instalación construida está diseñada para simular un ambiente de descarga en ciertas condiciones del motor en las que podrían producirse fenómenos de flash boiling. Así, debido a las propiedades típicas del combustible de gasolina, era un requisito operar con presiones de cámara de 0,2 a 15 bares. Además, la temperatura ambiente se controlaba mediante la implementación de una resistencia que puede calentar el gas ambiente. La instalación funciona en un bucle abierto, pudiendo renovar el volumen de gas entre las inyecciones. Por último, se construyeron tres amplios accesos ópticos para acomodar muchas técnicas de diagnóstico óptico como DBI, MIE, shadowgraphy o PDA, entre otros. Para la evaluación del flujo interno se determinó la geometría de las toberas y la orientación de los agujeros, el movimiento de la aguja y, por último, la caracterización del ratio de inyección (ROM) y el momento de inyección (ROI) de ambas toberas. La geometría de las toberas y la elevación de la aguja se midieron mediante técnicas avanzadas de rayos X en el Laboratorio Nacional de Argonne (ANL). Las mediciones de ROI y ROM se realizaron utilizando las instalaciones de CMT-Motores Térmicos siguiendo los conocimientos técnicos aplicados en los inyectores de gasóleo y adaptándolos a las toberas de GDI. El ROI nos permitió comparar las boquillas, cuyo número de orificios y geometría eran diferentes, aunque entregan aproximadamente la misma cantidad de combustible. Se ensayó la respuesta a condiciones típicas de motor como variaciones en la presión del rail, la presión de descarga, la temperatura del combustible, etc. Para el inyector de investigación "Spray G", se desarrolló un modelo 0-D de la velocidad de inyección que permite obtener la señal para diferentes condiciones y duración de la inyección, lo cual es útil para la calibración del motor y la validación del CFD. Además, para la caracterización de la ROM, se desarrolló la metodología de la técnica de deformación plástica para obtener la orientación del cono del spray y orientar adecuadamente los chorros de combustible para la medición de ROM. En el análisis hidráulico se combinaron los datos para estudiar los bajos valores del coeficiente de descarga y / [CA] La injecció de combustible és, entre els temes d'investigació de motors, una de les peces crítiques per a obtindre un motor eficient. El paper és encara més significatiu quan es persegueix una estratègia d'injecció directa. La geometria interna i el moviment de l'agulla determinen el comportament del flux de l'injector, que se sap que afecta enormement el desenvolupament extern de l'esprai i, en última instància, al rendiment de la combustió dins de la cambra. La consciència sobre el canvi climàtic i els contaminants ha anat creixent, impulsant l'esforç en motors més nets. En aquest sentit, els motors de gasolina tenen un marge més ampli per a millorar que els motors dièsel. L'evolució dels antics PFI a les modernes estratègies d'injecció directa, que s'utilitzen en els motors de nova generació, demostra aquesta tendència. Els sistemes GDI tenen el potencial de complir amb les estrictes emissions i aug- mentar l'estalvi de combustible, no obstant això, encara s'enfronta a molts desafiaments. Aquest treball implica l'ús de dos injectors, un és una moderna tovera de GDI d'investigació designada pel Engine Combustion Network (ECN), i l'altre és una unitat d'injecció de producció (PIU) amb la mateixa tecnologia i una geometria lleugerament diferent. Tots dos equips se sotmeten a una completa caracterització (flux intern i extern) que abasta les tècniques més avançades en diverses instal·lacions experimentals. A més, es dissenya i construeix una nova instal·lació per a realitzar experiments en condicions d'evaporació instantània (quan la pressió de vapor del combustible injectat és superior a la pressió del volum de descàrrega). La instal·lació construïda està dissenyada per a simular un ambient de descàrrega en certes condicions del motor en les quals podrien produir-se fenòmens de flash boiling. Així, a causa de les propietats típiques del combustible de gasolina, era un requisit operar amb pressions de cambra de 0,2 a 15 bars. A més, la temperatura ambient es controlava mitjançant la implementació d'una resistència que pot calfar el gas ambiente. La instal·lació funciona en un bucle obert, podent renovar el volum de gas entre les injeccions. Finalment, es van construir tres amplis accessos òptics per a acomodar moltes tècniques de diagnòstic òptic com DBI, MIE, shadowgraphy o PDA, entre altres. Per a l'avaluació del flux intern es va determinar la geometria de les toveres i l'orientació dels forats, el moviment de l'agulla i, finalment, la caracterització del ràtio d'injecció (ROM) i el moment d'injecció (ROI) de totes dues toveres. La geometria de les toveres i l'elevació de l'agulla es van mesurar mitjançant tècniques avançades de raigs X en el Laboratori Nacional de Argonne (ANL). Els mesuraments de ROI i ROM es van realitzar utilitzant les instal·lacions de CMT-Motores Térmicos seguint els coneixements tècnics aplicats en els injectors de gasoil i adaptant-los a les toveres de GDI. El ROI ens va permetre comparar els filtres, el nombre d'orificis dels quals i geometria eren diferents, encara que entreguen aproximadament la mateixa quantitat de combustible. Es va assajar la resposta a condicions típiques de motor com a variacions en la pressió del rail, la pressió de descàrrega, la temperatura del combustible, etc. Per a l'injector d'investigació "Esprai G", es va desenvolupar un model 0-D de la velocitat d'injecció que permet obtindre el senyal per a diferents condicions i duració de la injecció, la qual cosa és útil per al calibratge del motor i la validació del CFD. A més, per a la caracterització de la ROM, es va desenvolupar la metodologia de la tècnica de deformació plàstica per a obtindre l'orientació del con de l'esprai i orientar adequadament els dolls de combustible per al mesurament de ROM. En l'anàlisi hidràulica es van combinar les dades per a estudiar els baixos valors del coeficient de descàrrega i del coeficient d'àr / [EN] Fuel injection is among the engine research topics one of the critical pieces to obtain an efficient engine. The role is even more significant when a direct injection strategy is pursued. The internal geometry and pintle movement determine the injector flow behavior, which is known to hugely affect the external spray development and, ultimately, the combustion performance inside the chamber. Climate change and pollutants awareness has been growing, pushing forward the effort on cleaner engines. In this regard, gasoline en- gines have a wider margin to improve than diesel engines. The evolution from old Port Fuel Injectors to modern direct injection strategies, which are used in new generation engines, demonstrates this trend. GDI systems have the potential to comply with stringent emissions and increase fuel economy, however, it still faces many challenges. This work involves the use of two injectors, one is a modern research GDI nozzle appointed by the Engine Combustion Network (ECN), and the other is a production injector unit (PIU) with the same technology and slightly different geometry. Both hardware's undergo a complete characterization (internal and external flow) covering the state- of-the-art techniques in various experimental facilities. Furthermore, a new facility is designed and built to perform experiments under flash boiling conditions (when the fuel injected's vapor pressure is higher than the pressure in the discharge volume). The developed facility is designed to simulate a discharge ambient at certain engine conditions in which flash boiling phenomena could occur. Thus, due to typical gasoline fuel properties, it was a requirement to operate from chamber pressures from 0.2 bar to 15 bar. Also, the ambient temperature was controlled by implementing a resistor that can heat the ambient gas. The facility operates in an open loop, being able to renovate the gas volume between injections. Finally, three wide optical accesses were built to accommodate many optical diagnostic techniques such as DBI, MIE, shadowgraphy, or PDA, among others. For the internal flow description, it was determined the nozzles geometry and holes orientation, the pintle movement, and finally, the characterization of the rate of momentum (ROM) and rate of injection (ROI) of both nozzles. The nozzles geometry and needle lift were measured using advanced optical x-ray techniques at Argonne National Laboratory (ANL). The ROI and ROM measurements were performed using CMT-Motores Térmicos facilities follow- ing the know-how applied in diesel injectors and adapting it to GDI nozzles. The ROI allowed us to compare the nozzles, whose orifices number and geometry were different, although they deliver approximately the same amount of fuel. It was tested their response to typical boundary conditions such as rail pressure, discharge pressure, fuel temperature, etc. For the research nozzle "Spray G", it was developed a 0-D model of the rate of injection allowing to obtain the signal for different injection duration and conditions, which is useful in engine calibration and CFD validation. Furthermore, for the ROM characterization, the plastic deformation technique methodology was developed to obtain spray cone orientation and adequately guide the fuel jets for measuring ROM. The hydraulic analysis combined the data to study the low discharge coefficient and area coefficient values, which could result from low needle lift combined with novel hole designs in both nozzles that promote cavitation and air interaction from inside the orifice. In the external flow characterization, it was used the new developed vessel to study the external spray covering flash boiling conditions. It was employed four surrogate fuels to simulate different volatility properties of gasoline com- pounds and ultimately reproduce more extreme flashing conditions. It was used lateral visualization using DBI and Schlieren in addition to frontal MIE visualization. Some of t / Bautista Rodríguez, A. (2021). Study of the Gasoline Direct Injection Process under Novel Operating Conditions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/167809

<p dir="ltr">The modern view of the plasma membrane is that of a complex, highly dynamic, compartmentalized system that critically impacts multiple important cellular functions. Supported model membranes of well-defined compositions have emerged as attractive experimental platforms to determine the underlying molecular processes that regulate membrane-associated cellular functions using advanced biophysical detection methods with up to single molecule resolution. However, membrane properties of previously employed supported membrane systems, such as solid-supported lipid bilayer (SLB) and polymer-supported lipid bilayer with a polymer layer thickness of several nm, were found to be perturbed by the nearby solid substrate. To overcome this limitation, the present work describes for the first time the capillary-assisted formation of a lipid bilayer (CA-PGB) on the surface of a fully hydrated, several micrometers thick polyacrylamide gel. CA-PGB formation can be accomplished by physisorption or specific chemical linkages (tethering) between polymer gel and bilayer. Not dissimilar to conditions found in plasma membranes, membrane properties of CA-PGB are found to be solely influenced by the attached polymer layer. The successful formation and lipid fluidity of CA-PGB is confirmed using confocal microscopy and fluorescence correlation spectroscopy (FCS). Lipid bilayer spreading on the hydrogel surface by capillary-assisted assembly is not altered when the polymer gel stiffness or bilayer bending stiffness are varied, illustrating the robustness and versatility of the assembly process. This work also shows that, unlike other supported membrane systems, the capillary-assisted assembly approach causes the formation of a lipid reservoir at the edge of the capillary. This lipid reservoir provides a lipid supply for the CA-PGB, enabling bilayer self-healing and superior bilayer stability relative to SLB. Experimental data are presented that support an assembly process, in which bilayer spreading on the gel surface inside the water capillary between two substrates is caused by monolayer collapse of suddenly accumulated lipids at the air-water interface of the capillary during sandwiching. A key aspect of the monolayer collapse-induced bilayer spreading is its rapid kinetics, which appears to be faster than the polymer gel swelling kinetics. The importance of the fast kinetics of bilayer spreading during capillary-assisted assembly is supported by the observation that attempts to build polymer gel-supported lipid bilayer using traditional lipid assembly methods [i. e., Langmuir-Blodgett (LB)/Langmuir-Schaefer (LS), LB- vesicle fusion, and spontaneous bilayer spreading from a hydrated lipid source], characterized by slower bilayer spreading kinetics, are unable to form a homogeneous fluid lipid bilayer on the polymer gel surface. The experimental results obtained in this work strongly suggest that the CA-PGB not only represents a powerful experimental model membrane platform for the analysis of membrane-associated processes relevant in cellular membranes, but also serves as promising cell surface mimetic to probe the cellular mechanosensitivity of adherend cells.</p>

Kollapsen av den klassiska Mayakulturen under sen 700- till sen 900-tal e.Kr. har förbluffat forskare ända sedan studier av Mayakulturen påbörjades på 1840-talet. Både arkeologer och antropologer som epigrafiker eller klimatforskare har arbetat med att lösa gåtan av hur ett kulturellt vidsträckt samhälle kunde kollapsa utan någon klar förklaring. Civilisationen som än idag talar till oss genom sina kolossala pyramider och tempel, inskriptioner och den vetenskapliga kunskapen som ansetts outförbara utan moderna instrument. Dock har inte kollapsen varit ett direkt fokus i Mayastudier sedan forskningen påbörjades. Det var inte förrän på 1960-talet som systematiska undersökningar utfördes för att hitta rimliga teorier till kollapsen. Ända sedan dess har hypoteser och teorier haglat in och forskarna idag hittar sig själva i en sjö av oförklarlig information. Kunskapen av Mayakulturen är enorm men det har inte hjälpt att hitta någon bestämd teori om kollapsen av klassiska Maya. Det finns forskare som fokuserar på stora katastrofala händelser såsom drastiska klimatförändringar, sjukdomar eller jordbävningar så svåra att återhämtning var omöjligt. Sedan finns den andra skaran av forskare som förkastar enskilda händelser och fokuserar mer på mångfaldiga katastrofer som kunnat utlösa ödesdigra mönster i samhället som till slut utmynnat i en kollaps. Trots oklarheter kring kollapsen har framsteg gjorts inom fältet. Många teorier har mycket tack vare avancerade metoder kunnat förkastas medan andra blivit mer debatterade. Vad som än Mayakulturen kan berätta för oss, står ändå kollapsen som den stora nöten att knäcka och ju längre forskningen av ämnet fortgår desto närmare kommer även forskare till svaret. Frågor dyker dock fortfarande upp om det är möjligt att lösa en av arkeologins stora gåtor.

VYSOKÉ UČENÍ TECHNICKÉ V BRNĚ The purpose of this work is to design and implement a computer system, which should be used for simplification of a polygonal models in 3D space. The system should be allowed to reduce a given number of geometrical primitives from source object. User should have impact to the reducing process by selecting a method, size of target object etc. System uses 3DS file format for model loading and saving. Reader should understand principles of the polygon reduction and used algorithms.

The last two decades have seen new insights, data and analytical methods to establish the behaviour of structures in fire. These methods have slowly migrated into practice and now form the basis for modern quantitative structural fire engineering. This study presents a novel methodology for determining the imposed heat fluxes on structural members. To properly characterise the temperature rise of the structural elements, a post-processing model for computational fluid dynamics tools was developed to establish the heat fluxes imposed on all surfaces by a fire. This model acts as a tool for any computational fluid dynamics model and works on the basis of well resolved local gas conditions. Analysis of the smoke layer and products of combustion allow for heat fluxes to be defined based on smoke absorption coefficients and temperatures. These heat fluxes are defined at all points on the structure by considering full spatial and temporal distributions. Furthermore, heat fluxes are defined by considering directionality and both characteristic length and time scales in fires. Length scales are evaluated for different structural member geometries, while time scales are evaluated for different structural materials including applied fire protection. It is the output given by this model that provides the input for the thermal analysis of the structural members that is a necessary step prior to the structural analysis to be undertaken. The model is validated against the experimental results of the previously mentioned large scale fire tests, showing good agreement. In addition, comparisons are made to current methods to highlight their potential inadequacies.

Ce mémoire étudie, par la voie de la modélisation numérique, le comportement des murs en terre armée sous l'effet de la corrosion des armatures. L'analyse de données recueillies sur des ouvrages réels, âgés de plusieurs dizaines d'années, a montré la différence de comportement selon les types d'armatures, mais aussi la forte dispersion de l'ensemble des données. Elle a permis de proposer des relations entre la perte de masse et la diminution de la résistance et de l'allongement à la rupture des armatures.La présence des armatures très minces par rapport aux dimensions de l'ouvrage rend intéressante l'utilisation de méthodes d'homogénéisation. On a retenu une modélisation multiphasique, qui permet une modélisation satisfaisante de la traction dans les armatures.Quatre scénarios de corrosion ont été étudiés pour prendre en compte diverses situations susceptibles de conduire à des taux de corrosion élevés. La répartition spatiale de la corrosion peut avoir une influence importante sur le comportement du mur, sur le mécanisme de ruine et provoquer des phénomènes complexes de report des effort d'une armature sur une autre.Nous avons réalisé une étude paramétrique de l'effet de surcharges appliquées à l'ouvrage, et de certains détails de modélisation comme la jonction entre écailles, et la jonction entre armatures et écailles. Les résultats obtenus sont comparés à des mesures sur des ouvrages réels ou des modèles réduits, et à d'autres résultats de calcul.Les résultats conduisent à formuler des propositions concernant le suivi des déformations des ouvrages (nature et précision des mesures à effectuer, intervalles de temps entre inspections successives) / This thesis presents numerical simulations of the behavior of reinforced earth walls induced by the corrosion of the reinforcement strips. The preliminary analysis of a database, gathering results of laboratory tests, performed on soil and steel samples extracted from wall built several decades ago, has shown the difference in behavior between different types of reinforcement strips, and the large scattering of data. It served as a basis to derive relationships between weight loss, ultimate strength and ultimate strain of reinforcement strips.The presence of very thin strips compared to the size of the reinforced earth wall makes it interesting to use homogenization methods. We adopted a multiphase model, that makes it possible to get a satisfactory modeling of the tensile forces in reinforcement strips.We studied four corrosion scenarios to take into account various situations in which corrosion rates can become significant. The spatial distribution of corrosion can have a clear influence on the behavior of the wall, the failure mechanism, and create complex redistributions of tensile forces between adjacent strips. Parametric studies were carried out to investigate the effects of surcharges, and of some details of modeling, such as the junction between panels, or the junction between the reinforcement strips and the facing panels. Results have been compared with measures obtained on full scale reinforced earth walls or on physical models, and with results of other numerical simulations. Results provide elements for the definition of a strategy for the monitoring and the surveillance of reinforced earth walls

Capillaries in tumours are often severely buckled (in a plane perpendicular to the axis) and / or chaotic in their direction. We develop a model of these phenomena using nonlinear solid mechanics. Our model focusses on the immediate surrounding of a capillary. The vessel and surrounding tissue are modelled as concentric annulii. The growth is dependent on the concentration of a nutrient (oxygen) diffusing from the vessel into the tumour interstitium. The stress is modelled using a multiplicative decomposition of the deformation gradient F=F_e F_g. The stress is determined by substituting the elastic deformation gradient F_e (which gives the deformation gradient from the hypothetical configuration to the current configuration) into a hyperelastic constitutive model as per classical solid mechanics. We use a Blatz-Ko model, parameterised using uniaxial compression experiments. The entire system is in quasi-static equilibrium, with the divergence of the stress tensor equal to zero. We determine the onset of buckling using a linear stability analysis. We then investigate the postbuckling behaviour by introducing higher order perturbations in the deformation and growth before using the Fredholm Alternative to obtain the magnitude of the buckle. Our results demonstrate that the growth-induced stresses are sufficient for the capillary to buckle in the absence of external loading and / or constraints. Planar buckling usually occurs after 2-5 times the cellular proliferation timescale. Buckles with axial variation almost always go unstable after planar buckles. Buckles of fine wavelength are initially preferred by the system, but over time buckles of large wavelength become energetically more favourable. The tumoural hoop stress T_{ThetaTheta} is the most invariant (Eulerian) variable at the time of buckling: it is typically of the order of the tumoural Young's Modulus when this occurs.

L'étude des signes précurseurs d'un effondrement brutal au-dessus de cavités souterraines, dont le recouvrement est caractérisé par la présence d'un banc massif et raide, est un problème majeur pour la sécurité publique. Aussi, pour progresser dans la compréhension et l'évolution des mécanismes mis en jeu, une cavité saline, située dans le NE de la France, a été suivie en temps réel, entre 2004 et 2009, jusqu'à son effondrement. Celle-ci a été exploitée par dissolution, jusqu'à atteindre une dimension critique (de l'ordre de 180 m) sous un recouvrement de 180 m, armé d'un banc raide de Dolomie situé à 120 m de profondeur.Un système de mesures multi-paramètres haute résolution visait à caractériser les signes précurseurs ainsi qu'à suivre l'effondrement lui-même. Il comprenait des dispositifs à la fois géotechniques et géophysiques, dont des mesures de nivellement de surface et un réseau permanent d'écoute microsismique. Ce dernier, dont les données font l'objet principal de cette thèse, était constitué de neuf sondes équipées de géophones 40 Hz (5 unidirectionnels et 4 tridirectionnels), réparties autour et à l'aplomb de la cavité, dont une dans le banc raide.L'évolution de la cavité a été marquée par deux épisodes majeurs d'activité microsismique :- au printemps 2008, la reprise de la dissolution dans la cavité a engendré l'apparition de crises répétées avec plusieurs milliers d'événements en quelques jours, traduisant un changement de régime microsismique, marqueur de l'instabilité de la cavité ;- en février 2009, suite à ces observations, l'exploitant a décidé de provoquer l'effondrement, par le rabattement intensif de saumure dans la cavité. Pendant les trois jours d'opération, plus de 30000 événements ont été enregistrés (sur 60000 depuis 2004).L'étude de la signature des événements apporte des renseignements essentiels pour la surveillance opérationnelle et la discrimination de ces deux périodes. En particulier, alors que les valeurs maximales atteintes en amplitude, énergie au capteur et fréquence fondamentale apparente, sont assez stables au cours des crises, les sauts marqués durant l'effondrement, permettent de présumer de son imminence. L'évolution de la distribution des microséismes en termes d'énergie libérée et d'occurrence, calculée de manière similaire à la loi de Gutenberg-Richter, bien que souvent difficile à interpréter, a pu être associée à des hausses du niveau piézométrique, ainsi qu'à de petites accélérations de l'affaissement mesuré en surface. Pendant la période d'effondrement, le nombre d'événements microsismiques augmente en suivant une loi en puissance.La localisation des microséismes a nécessité la mise en place d'une stratégie adaptée pour garantir la qualité et l'homogénéité des résultats (sélection des enregistrements, calibrage, étude paramétrique).Cependant, l'utilisation d'un modèle de vitesse constant sur toute la période s'est révélé impossible, compte tenu de l'évolution rapide et permanente du milieu. Il a donc été entrepris d'établir des modèles de vitesse différents en fonction des périodes d'évolution de la cavité.Les distributions spatio-temporelles des foyers ainsi localisés montrent l'existence de structures préférentielles de rupture et souligne le rôle majeur du banc raide.Croisées avec les autres mesures acquises sur le site, ces résultats ont permis d'établir un scénario probable d'évolution de la cavité et de proposer quelques recommandations pour la surveillance opérationnelle / The study of the precursory signs of a brutal collapse above underground caverns, with an overburden characterized by the presence of a massive and stiff bench, is a major problem for public safety. Thus, to progress in the comprehension and the evolution of the concerned mechanisms, a salt cavern, located in the NE France, was monitored in real-time, since 2004 to 2009, until its collapse. This cavern was mined by solution, until reaching its critical dimension (about 180 m) under a covering of 180 m thick, armed with a stiff Dolomite bench located at 120 m of depth.A multi-parameter high resolution monitoring system aimed at characterizing the precursory signs and following collapse itself. It included both geotechnical and geophysical devices as surface leveling measurements and a permanent microseismic network. This one, which data are the principal subject of this thesis, consisted in nine probes equipped with 40 Hz geophones (5 1D and 4 3D), distributed around and directly below the cavern, including one located in the stiff bench.The evolution of the cavern was marked by two major episodes of microseismic activity:- at the beginning of spring 2008, the dissolution restart in the cavern which caused repeated crisis with several thousand events in a few days, this represent a change in the microseismic regime and marked the cavern instability;- in February 2009, following these observations, the owner decided to trigger the collapse by intensive brine pumping in the cavern. During the three days of the operation, more than 30,000 events were recorded (against 60,000 since 2004).The study of the event signature provides essential information for operational monitoring and the discrimination of these two periods. Particularly, while maximal values reached in amplitude, energy and apparent fundamental frequency are quite stable during the 2008 episodes, the rises of this values are important during the collapse period (prior to the peak of activity), allowed us to suppose its imminence. The evolution of the microseism distribution in terms of energy released and occurrence, calculated similarly to the Gutenberg-Richter law, although often difficult to interpret, has been associated with piezometric level rises, and with small accelerations of surface subsidence. During the collapse, the microseismic activity acceleration follows a power law.Microseisms location required the establishment of an appropriate strategy to ensure the quality and the consistency of the results (record selection, calibration, parametric analysis). However, the use of a constant velocity model over all the period was impossible due to the fast and permanent evolution of the environment. Thus, several models were used, according to the a priori known cavern evolution.The event spatiotemporal distributions, thus located, revealed the existence of preferential failure structures and highlight the role of the stiff bench, located at 120 m depth

This dissertation examines Peter Singer's proposed ethical value of the "person" in Rethinking Life and Death . Chapter 1 introduces and outlines Singer's proposal, which argues for abortion, infanticide, euthanasia, and assisted suicide. His proposal consists of four key points. First, there is the foundation for his proposal--rejecting creation for evolution. Second, there is the substance of his proposal--replacing the value of the "human" with the value of the "person." Third, there is the criteria for his proposal--using "indicators" and "relevant characteristics" to identify the kinds of beings who qualify as "persons." Fourth, there are the consequences of his proposal--promising an ethical "Copernican Revolution." Chapters 2-5 critically evaluate the four key ideas from Singer above. The evaluation of the respective key idea in each chapter covers five steps: (1) the context of Singer's proposal; (2) the content of Singer's proposal; (3) positive evaluation; (4) negative critique; and (5) conclusion. The research methodology for the dissertation is to treat Singer's ethical proposal on the "person" as a hypothesis to be tested by his own truth standards of logical consistency, empirical evidence, and practicality. Following these four key chapters, Chapter 6 provides "Summary and Conclusions." The conclusion of this dissertation is that Peter Singer's proposal on life and death is not to be commended because its key elements are not supported by his own standards for testing truth. In fact, when examined by his own truth tests, Singer's program should be rejected because its foundation is faulty, its substance is illusory, its criteria are circular, and its consequences would be grave. / This item is only available to students and faculty of the Southern Baptist Theological Seminary. If you are not associated with SBTS, this dissertation may be purchased from <a href="http://disexpress.umi.com/dxweb">http://disexpress.umi.com/dxweb</a> or downloaded through ProQuest's Dissertation and Theses database if your institution subscribes to that service.