Дисертації з теми "Analyse d’empreinte de pression"
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Bancora, Simone. "Characterization of fabric layups by pressure print analysis and simulation of dual-scale flow based on topological skeletonization : application to composite materials processing." Thesis, Ecole centrale de Nantes, 2021. http://www.theses.fr/2021ECDN0049.
In this work, we study continuous fiber preforms in the context of Resin Transfer Moulding (RTM) processes. The aim of the thesis is two-fold: propose a new methodology to obtain mesoscale geometrical data from preforms and provide a new numerical model able to predict permeability or perform mesoscale filling simulations in a computationally efficient way. In the first part, the focus is on the acquisition of geometrical data from preforms: we propose a novel methodology based on the analysis of the pressure field experienced by a dry preform under compaction. By using a commercial pressure-sensitive film, the pressure field exerted by a stack of layers against mould walls is captured and analyzed. Taking advantage of the periodic morphology of textiles, geometric patterns revealed by the pressure field are interpreted according to spectral Moiré analysis to recover the orientation and spatial distribution of each individual layer in the stack. In the second part, the reconstructed digital architecture of the preform is used to carry out numerical flow simulations at the scale of the yarns, to characterize permeability of the stack or directly perform filling simulations. The stack geometry is replaced by a skeletonized representation of the same, on which a two-dimensional flow problem can be solved numerically, greatly reducing the computational cost when compared to a full 3D approach. This “medial skeleton” model is first formulated in its single-scale version (flow in channels) and then extended to dual-scale (flow in channels and yarns). The model potential is illustrated through several test cases. This research establishes a pathway going from the non-destructive acquisition of data to the simulation of the dual-scale flow inside a multi-layer layup of textiles
Thébault-Leborgne, Ludmila. "Analyse expérimentale d'un plasma d'argon supersonique, turbulent, basse pression." Rouen, 1998. http://www.theses.fr/1998ROUES058.
Nourhashemi, Mina. "Analyse multimodale du couplage neurovasculaire chez le nouveau-né." Thesis, Amiens, 2018. http://www.theses.fr/2018AMIE0059/document.
Neurovascular coupling (NVC) has become the key aspect for understanding brain function. A multimodal exploration would aim to identify the early NVC biomarkers and determine their predictive character. Paper (1): In this chapter, the photothermal interaction of NIR laser on human tissues were modelled in silico. The results demonstrated the safety of the noninvasive optical evaluation of the brain function and the maximum temperature increase was higher in the neonatal brain than in the adult brain. Paper (2 & 3): The main purpose of this thesis was to provide a multimodal view of the NVC and cerebrovascular regulation in the neonatal premature brain. Paper (2): Key findings included that rCBV and rCMRO2 have a predominant driving influence on rCBF at the resting-state in the preterm neonatal brain. Paper (3): The bursts of electroencephalographic activity in neonates in resting state were found to be coupled to a transient hemodynamic response involving different types of hemodynamic response including: (a) positive stereotyped hemodynamic responses (increases in HbO, decreases in HbR together with increases in CBF and CMRO2), (b) negative hemodynamic responses (increases in HbR, decreases in HbO together with decreases in CBF and CMRO2), (c) Increases and decreases in both HbO-HbR and CMRO2 together with no changes in CBF. The establishment of neurovascular coupling system was observed as a function of age. High coherence was observed between the cerebral hemodynamic (vascular) and electrical (neuronal) oscillations which was less in the non-encephalopathic newborns than in the two pathological groups
Elefterion, Marie-Anne, and PHILIPPE ELEFTERION. "Pression artérielle ambulatoire : analyse de données recueillies chez 42 sujets normotendus, methode et intérêts, paramètres caractéristiques de la pression artérielle systolique, pression artérielle diastolique, fréquence cardiaque." Toulouse 3, 1987. http://www.theses.fr/1987TOU31203.
Feghali, Ramzi El. "Analyse des signaux de la pression artérielle, intérêts en pratique clinique." Lyon 1, 2007. http://www.theses.fr/2007LYO10060.
The aim of this work was to improve high-risk hypertensive care with cardiovascular outcomes especially metabolic syndrome. Blood pressure (BP) parameters and pulse wave velocity (PWV) were detected using non invasive technics. The first step consisted in analyzing the fiability of the oscillometric BP measurements in obeses with a large arm. As a second step, the effect of clinical or ambulatory BP, heart rate, and metabolic syndrome factors on arterial stiffness assessed by PWV was evaluated by conducting phase IV studies. Finally, we evaluated the BP normalization values after a short to medium term treatment of hypertensive diabetes and non diabetes with different antihypertensives (ARB : angiotensin 2 receptor blockers, ACEI : angiotensin converting enzyme inhibitors, and CCB : calcium channel blockers)
MALJEAN, BRUNO. "Hydrocephalie a pression normale idiopathique : etude clinique et pronostique, analyse statistique de 53 patients." Lyon 1, 1988. http://www.theses.fr/1988LYO1M044.
Solis, Coaguila Moisés Salvador. "Analyse numérique et expérimentale des fluctuations de pression dans les pompes centrifuges." Phd thesis, Paris, ENSAM, 2011. http://pastel.archives-ouvertes.fr/pastel-00676011.
Arpe, Alca Jorge Alejandro Arpe Jorge. "Analyse du champ de pression pariétale d'un diffuseur coudé de turbine Francis /." [S.l.] : [s.n.], 2003. http://library.epfl.ch/theses/?display=detail&nr=2779.
Landari, Hamza. "Analyse et conception d'une micropompe pour des applications à très faible pression." Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/28319.
In this project, a new architecture of an air-driven micropump prototype with self-actuating microvalves is presented. A finite element model is also presented. Fabrication and characterization of the system and the electronic control of the micro-pump was also introduced. The designed micropump was able to generate a flow rate of 9 µL/min. Pumping pressure was 1500 Pa. Frequency of membrane deformation was 1.25 Hz and its maximum deformation was 3.66 µm. Finite element modeling shows that the flow rate ratio between the admission and delivery phase was 99.99 %. Fabrication of the micropump was achieved through two processes. First, a manual molding for microvalves with cylindrical and cubic chambers whose external dimensions was 8 mm x 12 mm x 6 mm and actuation membrane thickness of 20 µm. The entire system, including the membrane, was made from polydimethylsiloxane (PDMS). Second, in collaboration with the department of mechanical engineering, a new printing process based on sugar glass was also used. The latter is based on the 3D printing of a sugar mold. The mold is dissolved after the pouring and curing of PDMS. The actuating chambers of the micropump wetre cylindrical with a diameter of 4 mm and a height of 1 mm. The pumping chamber was also cylindrical with the same diameter but with a height of 0.5 mm. The thickness of the pumping membranes was 250 µm. Through this process, the entire pumping system (expect microvalves) were fabricated as a one block to eliminate leakage and reduce system dimensions. The external dimensions of the micropump was 20 mm x 20 mm x 10 mm. Experimental results of the micro-pump showed that the flow rate that can be generated is 7 µL/min. The electrical power consumption of the system was 114 mW. Finally, the microvalve can resist to a back pressure up to 13 psi. A graphical interface to control the actuation part of the micropump using an FPGA has also been developed.
Lepage, Patrick. "Pression des pairs, Incitatifs et Qualité : une analyse expérimentale en situation de travail." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24478/24478.pdf.
Casanova, Jean-Jérôme. "Analyse et contrôle de systèmes fluide-structure avec conditions limites sur la pression." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30073/document.
In this thesis we study the well-posedness (existence, uniqueness, regularity) and the control of fluid-structure system with boundary conditions involving the pressure. The fluid part of the system is described by the incompressible Navier- Stokes equations in a 2D rectangular type domain coupled with a 1D damped beam equation localised on a boundary part of the fluid domain. In Chapter 2 we investigate the existence of strong solutions for this model. We prove optimal regularity results for the Stokes system with mixed boundary conditions in non-regular domains. These results are then used to obtain the local-in-time existence and uniqueness of strong solutions for the fluid-structure system without smallness assumption on the initial data. Chapter 3 uses the previous analysis in the framework of periodic (in time) solutions. We develop a criteria for the existence of periodic solutions for an abstract parabolic system. This criteria is then used on the fluid- structure system to prove the existence of a periodic and regular in time strict solution, provided that the periodic source terms are small enough. In Chapter 4 we study the stabilisation of the fluid-structure system in a neighbourhood of a periodic solution. The underlying linear system involves an operator A(t) with a domain which depends on time. We prove the existence of a parabolic evolution operator for this linear system. This operator is then used to apply the Floquet theory and to describe the asymptotic behaviour of the system. We adapt the known results for an operator with constant domain to the case of operators with non constant domain. We obtain the exponential stabilisation of the linear system with control acting on a part of the boundary of the fluid domain
Albenois-Gondelaud, Marie-Christine. "Urticaires et angiooedemes retardes a la pression : analyse de 60 cas du geru." Aix-Marseille 2, 1990. http://www.theses.fr/1990AIX20838.
Lagrandeur, Junior. "Imprégnation du bois assistée par des ondes de pression." Mémoire, Université de Sherbrooke, 2010. http://savoirs.usherbrooke.ca/handle/11143/1532.
Rohart, Philippe. "Mise en oeuvre de méthodes de dimensionnement par analyse appliquées aux équipements sous pression." Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10017.
Design by analysis of pressure vessels is placed within guidelines. Two methodologies are currently considered in international standards. The first one was proposed in the 60’ : it considers an elastic stress classification, depending on the nature of loads. It nowadays suffers from obsolescence, as technological demand and computational facilities increased considerably. The – much more recent – second one deals with elastoplastic calculations : it is based on limit and shakedown analysis theory, but causes applicative difficulties. The work achieved in this thesis begins with a state of the art, dealing with legal aspects of this industry, and detailing commonly-applied design rules and criteria. Several failure modes were identified, and the study focuses on two of them : gross plastic deformation and ratchet. Direct methods were selected for their relevance toward design considerations. Currently developed in research labs, they were studied, implemented, tested, and criteria were modified so as to take into account safety margins. Three solutions were explored : direct cyclic analysis, yield modification, and elastic compensation. For comparison purposes, methodologies were evaluated on academic and realistic cases. Accuracy and computational time were measured, along with the relation between these datas. Trends could be established, relating the pertinent use of a methodology to a problem complexity
Bouquillon, Jean. "Etude de la pression artérielle au cours de l'évolution du diabète insulino-dépendants : analyse des résultats obtenus par mesure ambulatoire de pression artérielle et FINAPRES." Lille 2, 1995. http://www.theses.fr/1995LIL2M101.
Schneewele, Manuel. "Implantation d'un E.N.T. dans l'enseignement secondaire, analyse et modélisation des usages : le cas lorrain." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0116/document.
The implementation, by local collectivity, of a VLE (Virtual Learning Environment) in secondary schools and high school is not without consequences for the educational community daily activities. Our study aims to understand emerging uses by carry out a decomposition of the appropriation process. It also responds to an institutional command whose aim is turned toward the promotion and stimulation of the utilisation of this type of tool. Therefore, our objective is to create a model to understand which are VLE users and how is managed the transition between uses prescribed by the creators and observed behaviors.For its concretization, our model is built on a set of preliminary work.- The operating frame study based on interviews with prescribers and the analysis of the Lorraine VLE project specification chart.- The use frame study, on one hand, through uses counter measures from the CDC (Caisse des Dépôts group), on the other hand, by questionnaires upon which functions we report first uses and social representation of a VLE and his book-texts by students, teachers and parents.The model pattern, supported by a robust literature, is called: DAME (Dynamic Acceptance Model for Education). It was applied to a population of 3,100 students, 774 parents, 617 teachers and 44 staff members of school life.The results show in a first step, the importance given to "usefulness" and "usability" perceptions. To promote the adoption of a VLA, and therefore its acceptability in the daily teaching activities, it's crucial that its handling and its added value were associated with its use are fully perceived. In a second step, it seems necessary to take into account, the social network of the user, what we call in our model "social pressure", students and staff of school life being particularly responsive to it. In a third step, we observe that tool properties can generate what we designate by "instrumental pressure" which retroactively impact on previous variables. Due to repeated use, addiction to ENT may be installed when it becomes essential for the quality of his professional or learning activity, which is notably the case for two functionalities: text-book and information space. Nevertheless, our model shows that other factors can be able to explain uses; therefore, new research prospects can be expected. Finally, it seems clear, on the basis of our various surveys, that the main beneficiaries of VLE are mainly parents and students. But if both show strong interest for its use, they are confronted to the resistance of some teachers denouncing an overwork and an excessive transparency of uploaded information
Laleg, Taous-Meriem. "Analyse de signaux par quantification semi-classique. Application à l'analyse des signaux de pression artérielle." Phd thesis, Université de Versailles-Saint Quentin en Yvelines, 2008. http://tel.archives-ouvertes.fr/tel-00357309.
Laghzale, Nor-Eddine. "Analyse des contraintes résiduelles dans les assemblages tubes-plaques à tubes dudgonnés par pression hydraulique." Mémoire, École de technologie supérieure, 2009. http://espace.etsmtl.ca/61/1/LAGHZALE_Nor%2Deddine.pdf.
Rochuon, Nicolas Trebinjac Isabelle. "Analyse de l'écoulemeent tridimensionnel et instationnaire dans un compresseur centrifuge à fort taux de pression." [S.l.] : [s.n.], 2007. http://bibli.ec-lyon.fr/exl-doc/nrochuon.pdf.
Laleg, Kirati Taous-Meriem. "Analyse de signaux par quantification semi-classique : application à l'analyse des signaux de pression artérielle." Versailles-St Quentin en Yvelines, 2008. http://www.theses.fr/2008VERS0041.
Cette thèse introduit une nouvelle méthode d'analyse de signaux, appelée SCSA, basée sur une quantification semi-classique. L'idée principale de la SCSA consiste à interpréter un signal en forme d’impulsions comme un puits de potentiel pour une particule semi-classique et à le représenter par les niveaux d’énergie discrets associés donnés par le spectre discret d’un opérateur de Schrödinger. La SCSA est une première étape vers une approximation par solitons (potentiels sans réflexion), qui définit une représentation parcimonieuse du signal, intéressante pour des applications en traitement du signal, par exemple la compression de données. Ce travail propose aussi un algorithme numérique pour l’estimation de signaux par la SCSA et présente les résultats de l’analyse des signaux de pression artérielle par cette méthode. En plus de la reconstruction satisfaisante de ces signaux, la SCSA introduit de nouveaux indices qui semblent véhiculer des informations physiologiques importantes
Torredème, Sophie. "Analyse et modélisation de la pression cylindre pour le contrôle des moteurs à allumage commandé." Toulouse, INPT, 1994. http://www.theses.fr/1994INPT085H.
Bultel, Arnaud. "Analyse d'un plasma d'azote basse pression en situations de jet libre et de couche limite." Rouen, 1994. http://www.theses.fr/1994ROUE5007.
Rochuon, Nicolas. "Analyse de l'écoulement tridimensionnel et instationnaire dans un compresseur centrifuge à fort taux de pression." Ecully, Ecole centrale de Lyon, 2007. http://bibli.ec-lyon.fr/exl-doc/nrochuon.pdf.
This study deals with a centrifugal compressor, designed and built by Turbomeca. Its impeller has a non-axisymmetric hub and was designed to evaluate the capacity of such a geometry to modify the flow structure within the compressor. The present study is based on both an experimental and a numerical approach. On one hand, it shows that the modification of geometry results in a decrease in intensity of the vortical structures. However, in the present design, this beneficial behavior is balanced by an increase in entropy in the vicinity of the shroud, because of the growth of the shear stresses. On the other hand, the application of analytic methods allows the extraction of the unsteady part of the rotor/stator interaction, from both the experimental and numerical unsteady results. In particular, the periodic modification in the shock wave structure at the diffuser inlet is shown to result in an increase in loss, compared with the loss predicted by steady calculations
Fauchet, Bertrand. "Analyse poroplastique des barrages en beton et de leurs fondations. Role de la pression interstitielle." Marne-la-vallée, ENPC, 1991. http://www.theses.fr/1991ENPC9121.
Bailly, Yannick. "Analyse expérimentale des champs acoustiques par méthodes optiques et microcapteurs de température et de pression." Besançon, 1998. http://www.theses.fr/1998BESA2080.
This work presents an original analysis of acoustic phenomena (low frequencies) inside and at the frontiers of cylindrical waves guides. With the hypothesis of the low reduced frequencies, we propose a theoretical model of the acoustic propagation, first for the infinite length duct and then for the real duct. Then we introduce phase lag phenomena to the reflection by using notably the complex notation. In the experimental analysis, we investigate all measurable physical quantities. In a first time, we use a miniature pressure sensor to access to the acoustic pressure. Then, we show how a thermoelectric junction of extremely reduced dimension (0. 5 micrometers) allows to measure a second thermodynamic quantity : the temperature. Thus, we find the temperature and the pressure experimental profiles in the resonator and notably in the thermal boundary layer. These simultaneous measurements also allow to determine a polytropic coefficient that charcterizes real thermodynamic transformations that govern acoustic phenomena. To complete this analysis, we develop several optical methods that allow to access to the acoustic elongation and to the flow structure at the openedend. Visualization techniques are largely described both on the theoretical plan and on the experimental plan. Finally, we show how a Laser Doppler Velocimeter (interference fringes) allows to reconstitute temporal evolution of the velocity field in the resonator. Again, we obtain the theoretical profile of the dynamic boundary layer
Lelong, Hélène. "Relations entre Mesures Non Médicamenteuses et Pression Artérielle. Analyse des données de l’étude NutriNet-Santé." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCD081/document.
Hypertension is the most prevalent chronic disease in the world and lifestyle behaviors, namely adherence to a healthy diet (rich in fruits and vegetables and with reduced consumption of salt), maintain of normal weight, regular physical activity and limitation of alcohol, for its prevention and control are recommended within worldwide guidelines. Our aim was to study the relationship between those recommended lifestyle behaviors and first blood pressure level and second risk of incident hypertension, through cross-sectional and prospective analyses using data from the NutriNet-Santé study, a French web-based cohort. Our results reported significant associations between body mass index, fruits and vegetables and alcohol consumption, and physical activity; confirmed the association of several nutritional factors and incident hypertension and highlighted that adopting a global healthy diet could strongly contribute to the prevention of hypertension. Moreover, adhere to all the recommended lifestyle behaviors could reduce the hypertension risk of half or at least delay the new onsets of hypertension
Bourgeois, Lydie. "Etudes structurales et dynamiques d'un composite d'inclusion incommensurable sous pression hydrostatique." Rennes 1, 2002. http://www.theses.fr/2002REN10055.
Seront, Bernard. "Déformation expérimentale à haute pression et haute température d'agrégats polycristallins de plagioclase et d'olivine." Montpellier 2, 1993. http://www.theses.fr/1993MON20139.
Ratier, Pierre-Nicolas. "Simulation du comportement des capteurs de pression capacitifs microélectroniques." Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0027.
Payer, Florent. "Prédiction et analyse du phénomène de réponse forcée : application à un cas de compresseur haute pression." Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-01063776.
Trassy, Christian. "Approche des mécanismes de transfert d'énergie dans les plasmas H.F. à pression atmosphérique utilisés en analyse." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb376016290.
Pereira, Jérémy. "Analyse et comportements des particules créées dans un plasma radiofréquence basse pression en mélange méthane/azote." Orléans, 2007. http://www.theses.fr/2007ORLE2032.
Franck, Raphaël. "Les annonces de politique de change en période de pression spéculative : une analyse théorique et empirique." Paris 2, 2002. http://www.theses.fr/2002PA020116.
Nguyen, Thi Phuong. "Simulation numérique et analyse physique des couches limites turbulentes compressibles sous l'influence des gradients de pression." Toulouse, INPT, 1998. http://www.theses.fr/1998INPT041H.
Rihane, Khadija. "Identification et dosage du tamoxifène et de ses métabolites N-déméthylés dans le plasma et dans la cuture de microsomes de rats-chromatographie en phase liquide à haute pression-barette de diodes-chromatographie en phase liquide à haute pression-fluorimétrie-chromatographie en phase gazeuse-spectométrie de masse (marquage isotopique)." Saint-Etienne, 2001. http://www.theses.fr/2001STET004T.
Lemaire, Jean-Jacques. "Analyse des ondes lentes de pression intracranienne chez l'homme : approche dans le domaine frequentiel : traitement du signal, aspects biophysiques, physiologiques, et physiopathologiques." Clermont-Ferrand 1, 1994. http://www.theses.fr/1994CLF1MM12.
Préau, Stéphane. "Etude théorique et numérique de l' "évaporation" d'une "goutte" de densité critique le long d'une isobare légèrement supercritique." Paris 6, 2003. http://www.theses.fr/2003PA066572.
Clinet, Sylvie. "Variabilité du champ de pression sur l'hémisphère nord extratropical : analyse des géopotentiels décadaires et mensuels à 700 et 500 hPa." Université Joseph Fourier (Grenoble), 1990. http://www.theses.fr/1990GRE19003.
Branchu, Samuel. "Plasticité de InSb [antimoniure d'indium] à basse température : analyse des microstructures par microscopie électronique en transmission." Poitiers, 1997. http://www.theses.fr/1997POIT2283.
Kennel, Nathalie. "Analyse comparative de deux tonomètres à air pulsé (X PERT NCT, TOP CON CT 20) au tonomètre de Goldmann." Université Louis Pasteur (Strasbourg) (1971-2008), 1992. http://www.theses.fr/1992STR1M195.
Pereira, de Souza Neto Edmundo. "Variabilité de la pression artérielle et de l'intervalle R-R : validation et analyse par méthode temps-fréquence." Lyon 1, 2000. http://www.theses.fr/2000LYO1T196.
LECOURT, STEPHANE. "Etude retrospective de 524 mesures ambulatoires de la pression arterielle : analyse globale et notion d'effet blouse blanche." Toulouse 3, 1994. http://www.theses.fr/1994TOU31042.
Ben, Ramdane Salem. "Analyse du champ de pression pariétale des surfaces portantes en mouvements instationnaires forcés par décomposition modale empirique." Nantes, 2008. http://www.theses.fr/2008NANT2117.
This work is conducted in the insight of the interest given to unsteady hydrodynamics of moving lifting bodies. We analyse the transient motion of a hydrofoil in a hydrodynamic water tunnel. Focus is given to the Parietal pressure field which constitutes the basis of hydrodynamic load on the hydrofoil. Experiments are carried at high Reynolds number where different phenomena are observed during the transient pitching motion of the hydrofoil. Pressure measurements on the hydrofoil' suction side reveals inception of phenomena such as laminar separation bubble, transition to turbulence and a separation bubble near the leading edge before stall occurs. Pressure signals are processed using a newly introduced method in signal processing. This latter, is suitable for non-stationary, non-linear signals processing. Differents approaches are proposed for signals decomposition and reconstruction. A time-frequency analysis is also conducted on the signals at the regions of interest to instabilities occuring at laminar separation bubble onset as well as leading edge separation
Sauton, Fabien. "Analyse des performances et des émissions d'un moteur diesel à injection haute pression fonctionnant au dimethyl ether." Paris 6, 2003. http://www.theses.fr/2003PA066481.
De, Bigault de Granrut Mathilde. "Analyse et interprétation de la pression d'eau en fondation des barrages-voûtes à partir des mesures d'auscultation." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI048/document.
The aperture of the rock-concrete interface of arch dams is a frequently observed phenomenon that shows through the non-linear features it induces in the local piezometry: threshold effects, couplings between its explanatory factors (hydrostatic effects, thermal effects, temporal effects). In order to interpret the corresponding monitoring measurements, it is necessary to take into account the non-additivity of those influences. This is not feasible with the multi-linear regression models that are commonly used in engineering. In that context, the aim of this thesis is to come to a better understanding of the hydraulic phenomena that occur at the rock-concrete interface based on the analysis and interpretation of monitoring measurements. In parallel, the objective is to characterise the state of deterioration of the contact, and more particularly its spatial extent, thanks to those measurements. To that end, two models were developed, the first one based on artificial neural networks, the second one based on a non-linear formulation of HST, enabling to make explicit the effects of the different loads on the flow. The interpretation of the piezometry in terms of reversible and irreversible effects made it possible to propose a geometrical characterisation of the contact state in an upstream-downstream profile, based only on the analysis of those effects. Then, an analytical flow model was expressed and investigated, built on this geometrical description of the contact. It permits to interpret the pressure field in several measuring points in one profile
Largeau, Jean-François. "Analyse expérimentale de la dynamique et du rayonnement acoustique d’un écoulement de marche montante." Poitiers, 2004. http://www.theses.fr/2004POIT2306.
The subject of this experimental study is the flow generated over a forward-facing step. The impact of several parameters (height of step and rate of flow) on the spatio-temporal flow organisation is investigated. The aim is also to clarify relationships between wall fluctuation pressure and the velocity field. Also, a model is designed and microphones probes are developed to investigated wall fluctuations pressures. Moreover, spatial flow organisation is examined with a Particle Image Velocimetry system for different configurations (height and flow rate). First the 2D hypothesis is improved (with wall flow visualisations experiments, hot-wire anemometry, wall pressure fluctuations probes). Moreover, spatial flow organisation is examined with a Particle Image Velocimetry system for different configurations (height and flow rate). The velocity field is mesurated simultaneously with the wall pressure fluctuations and acoustic pressure. Accordingly, the structure convection velocity, integrals flow scales and correlations between these different data are obtained overall the model. Finally, a Curle model computation is realised with experimental wall pressure fluctuations data and the estimated sound field is compared with acoustic measurements
Nisr, Carole. "Caractérisation des dislocations in situ dans les minéraux sous haute pression." Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10114/document.
The Earth mantle and inner core are submitted to large scale movements of solid materials. The physical process allowing the flow of solid materials is connected to plastic properties and, in particular, dislocations. It is the source of seismic wave velocities anisotropy. However, the deformation mechanisms of deep Earth minerals are poorly understood. Deep in the Earth’s interior, minerals are under extreme conditions; the temperature reaches several thousand degrees and the pressure is more than one million times the atmospheric pressure. The experimental study of the plasticity of those minerals requires deformation experiments under high pressure and temperature. High pressure phenomena are often determined from experiments using diamond anvil cell to reach the conditions of pressure and temperature of the mantle. The objective of this thesis was to develop a new technique for studying dislocations in situ in grains inside a polycrystal under high pressure, directly from their effect on the X ray diffraction profiles. To do so, we combine three-dimensional X-ray diffraction (3D-XRD) to X ray Line Profile Analysis method (XLPA). The development done in this thesis was applied to post-perovskite, the main constituent of the D'' layer at the core-mantle boundary and to stishovite, present mainly in subducting slabs. The results obtained are useful for understanding and modeling of convection and the development of seismic anisotropy in the mantle
Wattieaux, Gaëtan. "Détection et métrologie de nanoparticules en suspension dans un plasma froid basse pression." Thesis, Orléans, 2010. http://www.theses.fr/2010ORLE2080.
The recent development of nanotechnology has made nanoparticle sizing more and more important for the quality of manufactured products as well as for human health and environmental protection. The aim of this thesis was to look for innovative solutions to measure the size and the concentration of nanoparticles in dry environnement. To meet this requirement we focused on the physics of dusty plasmas because the desagglomeration of a powder sample is enhanced when it is exposed to a plasma and the dusts modify signifcantly the electrical properties of the plasma where they are trapped. The first result of this work is the determination of the mean size of dusts that are injected or formed in a RF low pressure capacitive discharge from the variations of the electrical parameters of the plasma and of the discharge. A new particle sizing technique has also been developed. It consists of determining the powder size distribution from the measurement of its sedimentation speed following the extinction of the discharge. The system that has been designed was successfully used to monitor in real time a nanopowder production line based at the CEA Saclay
Guéroult, Sébastien. "Analyse expérimentale de la saturation des milieux fibreux à double échelle de pores : application à la mise en oeuvre des matériaux composites par procédé RTM." Le Havre, 2012. http://www.theses.fr/2012LEHA0008.
The objective of this thesis is to contribute to a better understanding of the mechanisms during the impregnation in a dual scale porous media. As any process consisting in an injection of liquid into a fiber preform, RTM process is prone to have void type defects. Those defects may lead to a reduction of the final mechanical properties. To address this problem of void creation during infiltration, original experimental devices have been designed to measure the saturation in fibrous media. Sensors have been developed based on the electrical properties of materials: conductivity and permittivity. The saturation results show a dependency with the capillary number. Different mechanisms for the creation and transport of voids have been highlighted. These data are then correlated with pressure measurements. The evolution of the capillary pressure as a function of the capillary number has been introduced to characterize properly the impregnations. The correlation of all the data concerning saturation and pressure allows us to propose a new analysis of the permeability in dual scale porous media. Two concepts of permeability are defined: the geometric permeability as an intrinsic characteristic of the preform and the relative permeability as a function of the saturation
FEIGEL, PHILIPPE. "Analyse de la pression arterielle mesuree en continu au cours du sommeil : application au syndrome d'apnees du sommeil avant et avec traitement." Nantes, 1991. http://www.theses.fr/1991NANT079M.