Ce travail présente une étude théorique et expérimentale portant sur le concept de Moteur Hybride Pneumatique ( MHP). En première approche, un modèle 0D d'un MHP monocylindre, incluant un sous-modèle cinématique original pour l'actuateur entièrement variable muant la soupape de charge, est présenté puis exploité. La modélisation 1D de la dynamique des gaz dans chaque tubulure est traitée, incluant différents modèles de Condition Limite de Soupape (CLS), basées sur la méthode des caractéristiques et issues de la littérature. Il est montré que ces CLS ne sont pas adaptées à la modélisation d'un MHP : existence de chocs numériques, problème de non-convergence et mise en défaut face à des relevés expérimentaux. Un modèle original de CLS, évitant ces problèmes et demeurant basé sur la méthode des caractéristiques, est alors développé puis validé expérimentalement à la foi sur bancs d'essais moteurs et de dynamique des gaz à la soupape. Une étude expérimentale des échanges de chaleur convectifs, en mode pneumatique et sans combustion, est conduite et débouche alors sur une modification nécessaire de la corrélation standard de Woschni, afin de correctement décrire l'extinction du mouvement de tumble en fin de course de compression. Une exploitation de la plate-forme de simulation 1D de MHP monocylindre, incluant l'ensemble des éléments développés, est finalement conduite afin de déterminer les phasages optimums d'ouverture et de fermeture de la soupape de charge, pour différents mode et conditions opératoires. Cette étude, nécessaire à de futures simulations de cycles routier, confirme d'une part, la viabilité du concept et d'autre part, montre l'importance que revêt la prise en compte de la cinématique de l'actuateur soupape et de la dynamique des gaz dans la tubulure de charge.

Alors que le protéome de l'ovocyte isolé, aux stades VG et MII a déjà été étudié, celui du follicule en croissance n'a jamais été décrit.Dans cette étude, nous avons cherché à identifier, comparer et caractériser les profils protéiques de follicules ovariens de souris à trois stades de leur développement in vitro distincts morphologiquement : follicules secondaires en début de culture - stade initial (IS), follicules avec une rupture complète de la membrane de Slavjanski (RMS) et follicules avec une cavité similaire à l'antrum (FA).Après un préfractionnement par IEF et une analyse LC-MS/MS en deux configurations (1D et 2D), 1403 protéines ont pu être identifiées dans le follicule ovarien de souris. 43,4 % (609) des protéines identifiées étaient communes aux trois stades et d'autres ont été identifiées uniquement à un stade : 71 au stade IS, 182 au stade RMS et 193 au stade FA. De plus, on a identifié 365 protéines qui n'avaient pas été décrites antérieurement dans le protéome de l'ovocyte ce qui pourrais indiquer qu'elles sont exprimées dans les cellules somatiques du follicule. Des analyses qualitatives et quantitatives complémentaires ont démontré une surreprésentation pour 44 fonctions biologiques par rapport aux fonctions biologiques des gènes constituant le génome de Mus musculus et mis en évidence des différences d'expression et d'abondance des protéines liées au cycle cellulaire, à la fixation des ions de calcium et à la glycolyse selon le stade de développement. Ces résultats représentent un point de départ pour beaucoup d'autres études de caractérisation moléculaire du développement folliculaire.

Grâce à leurs propriétés originales de propagation de la lumière, les structures à cristal photonique présentent d’excellents atouts pour la réalisation de dispositifs de faibles dimensions et d’excellente qualité en vue du traitement classique ou quantique du signal. L’objectif de ce travail est de montrer l’exaltation des non linéarités du troisième ordre dans les structures à cristal photonique et de favoriser, grâce à des calculs théoriques et aux expériences conduites, la compréhension de ce phénomène aux multiples facettes. Nous montrons que la clé réside en la formidable capacité des cristaux photoniques à localiser la lumière en bord de bande interdite. Ce phénomène, directement relié au ralentissement de l’onde lumineuse à l’intérieur de la structure, permet de favoriser largement les processus non linéaire d’ordre trois. Au plan théorique, nous avons étudié, grâce à un formalisme matriciel étendu au cas non linéaire du mélange à quatre ondes, différentes structures 1D. Nous avons montré la forte exaltation de la réflectivité conjuguée en bord de bande interdite, celle-ci étant directement reliée à la forte localisation de la lumière à cette longueur d’onde. Les paramètres structuraux favorisant cette localisation sont également mis en évidence. Nous avons d’autre part mené différentes études spectroscopiques et résolues en temps sur des structures 1D à faible (CP II-VI) ou fort contraste (CP III-V) d’indice. Ces études ont montré que de très forts changements d’indice de réfraction sont possibles. Nous montrons également que de fortes densités de porteurs libres photo-générés par absorption multi photonique sont extrêmement favorisées en bord de bande interdite. Nous avons en outre étudié les structures 2D grâce à une décomposition en série de Fourier du réseau 2D et nous comparons les performances du cristal photonique 1D incliné et du cristal photonique 2D.

Cette thèse présente la conception et l'implémentation d'une nouvelle génération de puces à atomes, ouvrant de nouvelles perspectives expérimentales dans des micropièges magnétiques très anisotropes. Les propriétés thermiques des puces en nitrure d'aluminium sont étudiées en détail. Le dispositif a été optimisé pour piéger de plus grands nombres d'atomes et améliorer la qualité de l'imagerie, notamment en fabriquant un miroir de planéité sub-λ/10 à la surface de la puce.Nous étudions des gaz quasi-1D grâce à des images in situ de profils fluctuants et des méthodes précises de calibration et d'analyse statistique. Nous mesurons des fluctuations non-gaussiennes, ce qui permet de tester sensiblement la thermodynamique du gaz et donne une mesure de corrélations à trois corps. Nous étudions précisément la transition de quasicondensation et mesurons pour la première fois sa loi d'échelle. En régime 3D, c'est une condensation transverse qui déclenche la quasicondensation longitudinale, tandis qu'en régime 1D, la formation d'un quasicondensat est gouvernée par les interactions répulsives et non par la dégénérescence quantique.Obtenant des températures record pour des gaz 1D, nous observons des fluctuations subpoissoniennes lorsque les corrélations atomiques sont déterminées, au moins localement, par les fluctuations quantiques qui dominent les fluctuations thermiques. Nous discutons également la thermalisation étonnamment rapide mesurée en régime 1D profond qui suggère que des collisions effectives à 3 corps brisent l'intégrabilité du système.

L'imagerie par Résonance Magnétique permet de mesurer l'écoulement sanguin. Au niveau cardiovasculaire, elle permet d'acquérir non seulement des images anatomiques du cœur et des gros vaisseaux mais aussi des images fonctionnelles de vitesse par contraste de phase. Cette technique offre des perspectives dans l'étude de la dynamique des fluides et dans la caractérisation des artères, en particulier pour les grosses artères systémiques comme l'aorte dont le rôle est primordial dans la circulation sanguine. Par ailleurs, l'un des paramètres qui entrent en jeu dans la détermination de la fonction cardiaque et du comportement vasculaire est la pression artérielle. La méthode de référence de la mesure de pression dans l'aorte étant le cathétérisme, plusieurs méthodes combinant la modélisation à l'imagerie ont été proposées afin d'estimer un gradient de pression de façon non invasive. Ce travail de thèse propose de mesurer la pression dans un segment d'aorte grâce à un modèle 1D simplifié et en utilisant les données mesurées par IRM et un modèle 0D représentant le réseau vasculaire périphérique comme conditions aux limites. Aussi, afin d'adapter le modèle à l'aorte du patient, une loi de pression exprimant une relation entre la section aortique à la pression et basée sur la compliance a été utilisée. Cette dernière, liée à la vitesse d'onde de pouls (VOP), a été mesurée en IRM sur les ondes de vitesse.Par ailleurs, les séquences de codage de vitesse et d'accélération sont longues et ponctuées d'artéfacts dus au mouvement du patient. Une apnée est requise afin de limiter le mouvement respiratoire. Cependant, la durée de l'apnée atteint 25 à 30 secondes pour de telles séquences, ce qui est souvent impossible à tenir pour les malades. Une technique d'optimisation de séquences dynamiques par réduction du champ de vue est proposée et étudiée. La technique décrit un dépliement des régions repliées par différence complexe de deux images, l'une codée et l'autre non codée en vitesse. Cette méthode réalise une réduction de plus de 25% de la durée d'apnée.

Thailand has been often affected by severe flood events over the past century. The 2011’s Thailand Flood Catastrophe was the costliest in country’s history, and it was ranked to be the second most damaging natural hazard in the world in terms of economic losses. The Chao Phraya River Basin was noted to be the most vulnerable area prone to flooding in Thailand. The dynamics of flood risk in the river basin have changed drastically over the past fifty years. In particular, flood exposure increased due to rapid urbanization and population growth. Since 2012, integrated flood risk management has been addressed to be the major framework of water-related disasters with the goal of losses and damage reductions. However, there is currently little research in Thailand on how to quantify flood risks and mitigate flood inundation damage on the relation between the occurrence of flood events and their consequential socio-economic implications. In this study, a tradition method in flood risk assessment is implemented by integrating 2D hydrodynamic modelling and the assessment of socio-economic impact of floods into the Chao Phraya River Basin. More specifically, the fully 2D version of the LISFLOOD-FP model code was used to model flood inundation processes. The output of the model was then used to map inundation depth and assess the levels of physical/environmental risk associated to flood hazards on multiple receptors/elements at risk. The European Flood Directive and the KULTURisk methodology were applied to quantify flood risks in monetary terms for residential, industrial, and agricultural sectors. The 2011 flood event was used for model calibration, while a hypothetical flood event with a return period of 100 years was simulated to identify the potential flood losses. Depth-damage functions comprising of JRC-ASIA, the Flemish, and JICA models were used to estimate potential damage for residential and industrial structures. The results showed that LISFLOOD-FP could satisfactorily reproduce the flood inundation extent obtained from satellite imagery in 2011. The model performance (Critical Success Index or F1) was of 56%, with a Bias of 112%. The latter meant the total inundated area was 12% larger than flood extent’s observation. Moreover, the model could simulate flood levels with overall Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) of 2.03 m a.s.l. and 1.78 m a.s.l., respectively. For the estimation of flood damage and losses, the Flemish model showed the strongest agreement with the reported flood damage in the residential sector, while JICA-ASIA model underestimated flood damage for industrial sector by just 1%. The KULTURisk methodology also well-estimated crop losses in the 2011 event which an overestimation about 21% from the reported value. Apart from that, fully 2D numerical method could not perfectly represent 1-in-100 year flood inundation due to non-consideration of important features such as the precise river channel topography, hydraulic infrastructures, and flood protection schemes in the river basin. Lack of such features results in an overestimation of flood damage and losses for 1-in-100 year flood comparing to the national flood hazard map and damage assessment which are simulated and estimated by JICA’s study. Such features can be better handled by using a coupled 1D/2D numerical method in order to simulate flood inundation extent more realistically and estimate flood losses. This could help the Thai government to better prepare a budget for flood risk prevention. In addition, even if the Flemish model indicates a good representation of relative flood damage to housing structures, the government should establish depth-damage curves specific for Thailand.

A passagem progressiva de estados de Landau bidimensional (2D) para estados tridimensional (3D) foi estudada em Poços Quânticos Parabólicos (PQW) largos (W = 1000 6000 Å). Utilizou-se como técnica de transporte medidas da magnetoresistência em campo magnético intenso (B = 0 15 T) e inclinado ( = 0 90°; perpendicular paralelo), a baixas temperaturas (T = 50 mK). Observou-se, através da dependência angular das oscilações de Shubnikov de Haas ( = 0 90°), em PQWs cheios, várias sub-bandas ocupadas (5 a 8), a coexistência de estados de Landau 2D e 3D, sendo o gás 3D formado pelo colapso das sub-bandas elevadas, e o gás 2D pertencendo à primeira sub-banda. Através de cálculos do alargamento dos níveis de Landau devido ao espalhamento elástico ( = /2 , onde é o tempo quântico) e de cálculos auto-consistentes da energia de separação entre sub-bandas do PQW (ij = Ej Ei; e 12=12/2), obtiveram-se as condições 2 j-1,j para as sub-bandas elevadas j = 3,4,..., corroborando com as observações experimentais da coexistência de estados de Landau 2D e 3D no poço. Em PQWs parcialmente cheios, com apenas 2 sub-bandas ocupadas, observou-se, através do efeito do anticruzamento de níveis de Landau, de medidas da dependência angular da energia de ativação no regime de efeito Hall quântico, e de comparações com resultados de cálculos da estrutura eletrônica de PQWs em campo magnético inclinado, a coexistência de estados de Landau 2D e 3D, ocorrendo somente em campos intensos e com inclinação acentuada ( = 80 90°). Esta coexistência é diferente da mencionada anteriormente, quando od estados de Landau 3D são observados já em campo perpendicular. / The gradual progress, or evolution, of the two-dimensional (2D) toward three-dimensional (3D) Landau states was studied in wide parabolic quantum Wells (W = 1000 6000 Å). As transport technique, we used measurements of the magnetoresistence in intense (B = 0 15 T) and tilted ( = 0 90°; perpendicular parallel) magnetic Field at low temperature (T = 50 Mk). We observed in PQWs with Five to eight sub-bands occupied full well the coexistence of the 2D and 3D Landau states, through the angular dependence of the Shubnikov de Hass oscillation ( = 0 90°), where the 2D states belong to the lowest sub-band and the 3D states are formed by overlap of the other sub-bands. We calculated the level broadening due to the elastic scattering rate ( = /2 , where is the quantum time), and the energy separation between sub-bands (ij = Ej Ei; e 12=12/2). We obtained 2 j-1,j to j=3,4,... . This confirms the experimental observations of the coexistence of the 2D and 3D states in the well. We also measured PQWs partially full 2 sub-bands occupied. Experiments revel anticrossing of the Landau level (LL) belonging to the lowest sub-band and the last LL belonging to the second sub-band. Such antisrossuing occurs due to a decrease of the energy of the LL with tilt angle. This observation was supported by measurements of the angular dependence of the activation energy in the quantum Hall regime. In these measurements, we also observed the coexistence of the 2D and 3D Landau states. However, the coexistence only occurs at large tilt angles ( = 80 90°). Thus, it is different from the coexistence above mentioned, when 3D Landau states are observed already in the perpendicular magnetic field.

The concepts of engine downsizing and down-speeding offer reductions in CO2 emissions from passenger cars. These reductions are achieved by reducing pumping and friction losses at part-load operation. Conventionally, rated torque and power for downsized units are recovered by means of turbocharging. The transient response of such engines is, however, affected by the static and dynamic characteristics of the turbo-machinery. Recent advances in engine simulation and control tools have been employed for the purpose of the research reported in this thesis to identify and verify possible air-path enhancements. A systematic method for evaluating various turbocharger assistance concepts is proposed and discussed in this thesis. To ensure a fair comparison of selected candidate systems, an easily reconfigurable controller providing a close-to-optimal operation, while satisfying physical limits, is formulated. This controller is based on the Model Predictive Control framework and uses a linearised mean value model to optimise the predicted behaviour of the engine. Initially, the controller was applied to a 1D simulation model of a conventional light-duty Diesel engine, for which the desired closed-loop features were verified. This procedure was subsequently applied to various air-path enhancement systems. In this thesis, a turbocharger electric assistance and various concepts based on compressed gas injection were considered. The capability of these systems to improve engine response during third gear tip-in manoeuvre was quantified. This investigation was also complemented with a parametric study of how effectively each of the considered methods used its available resources. As a result, injecting compressed gas into the exhaust manifold was identified as an effective method, which to date has attracted limited attention from engine research community. The effectiveness of the exhaust manifold assistance was experimentally verified on a light-duty Diesel engine. The sensitivity of the improvements to compressed gas supply parameters was also investigated. This led to the development of the BREES system: a low component count, compressed gas based system for reducing turbo-lag. It was shown that during braking manoeuvres a tank can be charged to the level sufficient for a subsequent boost assistance event. Such a functionality was implemented with a very limited set of additional components and only minor changes to the standard engine control.

Voluntary coughs are used as a diagnostic tool to detect lung diseases. Understanding the mechanics of a cough is therefore crucial to accurately interpreting the test results. A cough is characterised by a dynamic compression of the airways, resulting in large flow velocities and producing transient peak expiratory flows. Existing models for pulmonary flow have one or more of the following limitations: 1) they assume quasi-steady flows, 2) they assume low speed flows, 3) they assume a symmetrical branching airway system. The main objective of this thesis is to develop a model for a cough in the branching pulmonary airway system. First, the time-dependent one-dimensional equations for flow in a compliant tube is used to simulate a cough in a single airway. Using anatomical and physiological data, the tube law coupling the fluid and airway mechanics is constructed to accurately mimic the airway behaviour in its inflated and collapsed states. Next, a novel model for air flow in an airway bifurcation is constructed. The model is the first to capture successfully subcritical and supercritical flows across the bifurcation and allows for free time evolution from one case to another. The model is investigated by simulating a cough in both symmetric and asymmetric airway bifurcations. Finally, a cough model for the complete branching airway system is developed. The model takes into account the key factors involved in a cough; namely, the compliance of the lungs and the airways, the coughing effort and the sudden opening of the glottis. The reliability of the model is assessed by comparing the model predictions with previous experimental results. The model captures the main characteristics of forced expiatory flows; namely, the flow limitation phenomenon (the flow out of the lungs becomes independent of the applied expiratory effort) and the negative effort dependence phenomenon (the flow out of the lungs decreases with increasing expiratory effort). The model also gives a good qualitative agreement with the measured values of airway resistance. The location of the collapsed airway segment during forced expiration is, however, inconsistent with previous experimental results. The effect of changing the model parameters on the model predictions is therefore discussed.

Recently, efforts have been made for self-powering the batteries and portable electronic devices by piezoelectric nanogenerators. The piezoelectric nanogenerators can work as a power source for nano-systems and also as an active sensor. The piezoelectric nanogenerator is a device that converts random mechanical energy into electrical energy by utilizing the semiconducting and piezoelectric properties. Also, the mechanical energy is always available in and around us for powering these nano devices. The aim of the present thesis work is to explore 1D and 2D ZnO nanostructures (nanorods and nanosheets) on metal alloy substrates for the development of piezoelectric nanogenerators in energy harvesting and sensors applications. Hydrothermal synthesis method was adopted for the growth of ZnO nanostructures. The nanogenerators were fabricated by using the optimized synthesis parameters and subsequently studied their performance for power generation and as an active speed sensor. These 1D and 2D nanostructures based nanogenerators have opened up a new window for the energy harvesting applications and sensors development. The thesis is divided into following six chapters. Chapter 1: This chapter gives a general introduction about energy harvesting devices such as nanogenerators, available energy sources, mechanical energy harvesting, ZnO material and the details on hydrothermal synthesis process. A brief literature survey on different applications of piezoelectric nanogenerators is also included. Chapter 2: A novel flexible metal alloy (Phynox) and its properties along with its applications are discussed in this chapter. Details on the synthesis of 1D ZnO nanorods on Phynox alloy substrate by hydrothermal method are presented. Further, the optimization of parameters such as growth temperature, seed layer annealing and substrate temperature effects on the synthesis of ZnO nanorods are discussed in detail. As-synthesized ZnO nanorods have been characterized using XRD, FE-SEM, TEM and XPS. Chapter 3: It reports on the fabrication of piezoelectric nanogenerator on Phynox alloy substrate as power generating device by harvesting the mechanical energy. Initially, the performance of the nanogenerator for power generation due to finger tip impacts was studied and subsequently its switching polarity test was also carried out. Output voltage measurements were carried out using the in-house developed experimental setup. Stability test was also carried out to see the robustness of the nanogenerator. Finally, the output voltage response of the nanogenerator was studied for its use as an active speed sensor. Chapter 4: Synthesis of Al doped 2D ZnO nanorsheets on Aluminum alloy (AA-6061) substrate by hydrothermal method is reported in this chapter. The optimized parameters such as growth temperature and growth time effects on the synthesis of ZnO nanosheets are discussed. As-synthesized ZnO nanosheets were characterized using XRD, FE-SEM, TEM and XPS. The Al doping in ZnO is confirmed by EDXS and XPS analysis. Chapter 5: Cost effective fabrication of Al doped 2D ZnO nanosheets based nanogenerator for direct current (DC) power generation is reported in this chapter. The performance of the nanogenerator for DC power generation due to finger tip impacts was studied and subsequently its switching polarity test was also carried out. Output voltage measurements were carried out using the in-house developed experimental setup. Stability test was also carried out to see the robustness of the nanogenerator. Finally, the DC output voltage response of the nanogenerator was studied for its use as an active speed sensor. Chapter 6: The first section summarizes the significant features of the work presented in this thesis. In the second section the scope for carrying out the further work is given.