Dissertations / Theses on the topic 'Matière condensée – Modèles mathématiques'
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Chiron, David. "Etude mathématique de modèles issus de la physique de la matière condensée." Paris 6, 2004. http://www.theses.fr/2004PA066053.
Théveniaut, Hugo. "Méthodes d'apprentissage automatique et phases quantiques de la matière." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30228.
My PhD thesis presents three applications of machine learning to condensed matter theory. Firstly, I will explain how the problem of detecting phase transitions can be rephrased as an image classification task, paving the way to the automatic mapping of phase diagrams. I tested the reliability of this approach and showed its limits for models exhibiting a many-body localized phase in 1 and 2 dimensions. Secondly, I will introduce a variational representation of quantum many-body ground-states in the form of neural-networks and show our results on a constrained model of hardcore bosons in 2d using variational and projection methods. In particular, we confirmed the phase diagram obtained independently earlier and extends its validity to larger system sizes. Moreover we also established the ability of neural-network quantum states to approximate accurately solid and liquid bosonic phases of matter. Finally, I will present a new approach to quantum error correction based on the same techniques used to conceive the best Go game engine. We showed that efficient correction strategies can be uncovered with evolutionary optimization algorithms, competitive with gradient-based optimization techniques. In particular, we found that shallow neural-networks are competitive with deep neural-networks
Herzog, Basile. "Chemically accurate simulations by machine learning correlated approximations." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0126.
The ability to systematically compute physical properties at chemical accuracy would be of tremendous help for efficient in silico material discovery, drug design or chemical reaction pathways study. While density functional theory has become the workhorse of materials simulations, the quality of results unfortunately often varies depending on the specific choice of the exchange-correlation functional, andthis significantly limits the predictive power of this approach. More correlated approaches, such a coupled cluster theory, the random phase approximation, or configuration interaction, provide more reliable results in a systematically improvable way. Their computational cost however render them inaccessible in a lot of applications, and this is particularly true for finite temperature properties, where many samples calculations are necessary to reproduce ensemble averages. Machine learning (ML) on the other, has proven its ability to efficiently reduce computational costs by using knowledge from previous calculations. The aim of this thesis is to contribute to the on-going development of ML assisted methods to obtain chemically accurate calculations. Machine learning perturbation theory (MLPT) is a recent promising approach capable of obtaining chemically accurate finite temperature properties by producing ensemble property estimates for highly expensive computational methods. This is achieved by learning the energy difference between two methods, using few samples from a reference statistics produced from a computationally feasible level of theory, and reweighting the later statistics to the computationally inaccessible target method, with thermodynamic perturbation theory (TPT). In this thesis, the MLPT method is tested against possible limitations of TPT, when a poor overlap between reference and target configurational space produce biased target estimates. A diagnostic test for this problem is proposed, together with a solution in the form of Monte Carlo resampling using the same ML model. MLPT is further applied to compute a coupled cluster estimate of the adsorption enthalpy of carbon dioxide inside a periodic zeolite. Finally, on another topic, a new method is presented, in the framework of configuration interaction (CI), to efficiently iteratively sample new Slater determinants using a generative ML model. This algorithm, called CIgen, is shown to be competitive or outperform other Monte Carlo and ML approaches to the CI problem
Lours, Thierry. "Etude structurale de la transformation sol-gel : caractérisation des aérogels et étude de leur densification par diffusion des rayons X aux petits angles." Montpellier 2, 1989. http://www.theses.fr/1989MON20012.
Nambully, Suresh Kumar. "A Filtered-Laminar-Flame PDF subgrid scale closure for LES of Premixed Turbulent Flames : Application to a Stratified Bluff-body burner with Differential Diffusion." Electronic Thesis or Diss., Rouen, INSA, 2013. http://www.theses.fr/2013ISAM0014.
A sub-grid scale closure for Large Eddy Simulation (LES) of turbulent combustion, based on physical space filtering of laminar flames is presented. The proposed formalism relies on a presumed probability density function (PDF) derived from the filtered laminar flames and flamelet tabulated chemistry. The combustion LES filter size is not fixed in this novel approach when sub-grid scale wrinkling occurs, but calibrated depending on the local level of unresolved scalar fluctuations. The model was validated by simulating 1D filtered laminar flames and 2D Bunsen flames. Subsequently, the model was tested on a 3D turbulent scenario by performing LES of the premixed and stratified configurations of the Cambridge swirl burner, experimentally studied by Sweeney and co-workers. Comparison of simulation and experiments for both the premixed and stratified configurations showed good agreement emphasizing the model characteristiscs. Instantaneous and time averaged LES data were analyzed to extract
Castel, Alexis. "Comportement vibratoire de structures composites intégrant des éléments amortissants." Phd thesis, Université de Bourgogne, 2013. http://tel.archives-ouvertes.fr/tel-00983378.
Petit, Xavier. "Etude de l'interaction cinétique chimique/turbulence dans une flamme cryotechnique LOx/CHA4." Phd thesis, INSA de Rouen, 2014. http://tel.archives-ouvertes.fr/tel-01020523.
Elmi, Robleh Hassan. "Modélisation numérique des écoulements pulmonaires." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00766647.
Seisson, Gabriel. "Etude expérimentale et théorique de l'endommagement du graphite sous sollicitation dynamique - Application aux impacts hypervéloces." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2014. http://www.theses.fr/2014ESMA0015/document.
Composite materials are widely used in various applications and may be submittedto hypervelocity impacts (HVI), such as in the aerospace field. The size of the impactors beingclose to that of a strand of fibers, mesoscopic simulations are of great interest but they need reliablenumerical models for each meso-Constituent. Graphite often being used as fiber or matrix,we studied its dynamic behavior. Penetration and craterization experiments have been conductedonto porous isotropic graphite. Post-Mortem analysis of targets, associated to order-Of-Magnitudecalculations, sheds a new light on the phenomenology of impacts and brings useful informationfor numerical simulation. A model for porous and brittle materials, implemented into a hydrocode,is used. Partially based on static mechanical properties, it has been progressively tested on planeshocks. Its use for simulating HVI gives satisfying results. Nevertheless, it was necessary to validateit by disregarding the projectile behavior. In that purpose, a campaign of laser-Driven shocks hasbeen conducted. In-Situ diagnostics have been simultaneously used and their correlation with postmortemanalysis allowed the identification of different damaging regimes of the targets. Finally,although the equivalence between HVI and laser-Driven shocks is not proved, the latter turned outto be complementary, suggesting the future evolutions of the numerical model
Fomin, Victor. "Modèles de Hubbard unidimensionnels généralisés." Chambéry, 2010. http://www.theses.fr/2010CHAMS024.
This thesis is devoted to the one-dimensional integrable Hubbard model and its generalizations. The Hubbard model is one of the fondamental models in condensed matter physics which describes nteracting electrons on the lattice. In one dimension the Hubbard model is an integrable model which bas been intensively studied and served as a theoretical laboratory for the condensed matter physics. Recently, the integrable systems and in particular the Hubbard model, have surprisingly appeared in the AdS/CFT correspondance context. In the first part of the thesis, we present basis notions of the quantum integrability. In the second part we review several fundamental results of the one-dimensional Hubbard model. Moreover, applications in the AdS/CFT duality are considered. However, certain modifications of the integrable Hubbard model are necessary to reproduce the correct results of the AdS/CFT context. This is one of the main motivations of the studies of generalized Hubbard models. The fourth chapter is devoted to generalizations of the Hubbard model and we focus our attention on supersymmetric ones. The fifth chapter contains the results obtained in the framework of this thesis on the supersymmetric generalizations of the Hubbard models. Namely, the Coordinate Bethe Ansatz solution and real solutions of the Bethe equations in the thermodynamic limit are exposed. We point out that we obtained Bethe equations differs from the Lieb-Wu ones by phases which appearance is encouraging sign for the application in the AdS/CFT context. We also discuss possible applications in the AdS/CFT duality and in condensed matter physics
Nambully, Suresh Kumar. "A Filtered-Laminar-Flame PDF subgrid scale closure for LES of Premixed Turbulent Flames : Application to a Stratified Bluff-body burner with Differential Diffusion." Phd thesis, INSA de Rouen, 2013. http://tel.archives-ouvertes.fr/tel-00845904.
Ngome, Abiaga Juste Jean-Paul. "(Super) symétries des modèles semi-classiques en physique théorique et de la matière condensée." Phd thesis, Tours, 2011. http://tel.archives-ouvertes.fr/tel-00622874.
Arryman, Arif. "Dynamique et simulation des marches de matière plastique." Paris 9, 1995. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1995PA090018.
This thesis concerns with the problem of dynamic modelling of market behavior. Its purpose is to introduce system dynamic simulation models capable of representing the dynamic of the polystyrene market. System dynamics methodology is employed as it provides conceptual devices that facilitate the clarification and formalization of mental model of market agents or experts. It facilitates also the conceptualization and formulation of complex relationships consist of time delays, non-linearity embedded in many interconnected feedback loops existing in the real-world market system. An aggregate and a competitive market models are constructed to represent the dynamic of the polystyrene market. The causal relationships and feedback structures of the models include classical economics forces and concepts such as market clearing through adjustment of supply and demand. Qualitative factors and concepts such as viscosity socio-psychology (elasticity) as well as accelerators of pressures psycho-financial (anticipation, speculation) underlying market mechanism. The analysis and simulation of model’s behavior produce insight and facilitate understanding and comprehension of the relationship between the complex behavior of the plastics markets and its underlying structure
Duret, Benjamin. "Simulation numérique directe des écoulements liquide-gaz avec évaporation : application à l'atomisation." Phd thesis, INSA de Rouen, 2013. http://tel.archives-ouvertes.fr/tel-00971810.
Enjalbert, Nicolas. "Modélisation avancée de la combustion turbulente diphasique en régime de forte dilution par les gaz brûlés." Phd thesis, INSA de Rouen, 2011. http://tel.archives-ouvertes.fr/tel-00735875.
Denèfle, Romain. "Modélisation locale diphasique eau-vapeur des écoulements dans les générateurs de vapeur." Phd thesis, Bordeaux 1, 2013. http://tel.archives-ouvertes.fr/tel-00919838.
Fajraoui, Noura. "Analyse de sensibilité globale et polynômes de chaos pour l'estimation des paramètres : application aux transferts en milieu poreux." Phd thesis, Université de Strasbourg, 2014. http://tel.archives-ouvertes.fr/tel-01019528.
Joyot, Pierre. "Modélisation numérique et expérimentale de l'enlèvement de matière : application à la coupe orthogonale." Bordeaux 1, 1994. http://www.theses.fr/1994BOR11040.
Joyot, Pierre. "Modélisation numérique et expérimentale de l'enlèvement de matière : application à la coupe orthogonale." Bordeaux 1, 1994. http://www.theses.fr/1994BOR10670.
Pereda, Jorge. "Formation des microstructures de solidification dans des alliages transparents modèles des alliages métalliques." Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0174.
The study of solidification microstructure formation is of utmost importance for the design and processing of materials, as solid-liquid interface patterns largely govern mechanical and physical properties. Pattern selection occurs under dynamic conditions of growth. The materials of choice for direct visualization of interface dynamics are transparent organic analogs. On Earth, convection alters the formation of cellular and dendritic microstructures. The micro-gravity of Space is therefore mandatory for fluid flow elimination in bulk samples. Over a hundred days of experiments between 2010 and 2011 were carried out in the DECLIC-DSI, (CNES-NASA) onboard the International Space Station. During the experimental campaign, a huge amount of data, mainly images, was obtained. The objective of this thesis work is to study the dynamics of formation and evolution of the interfacial array, from its birth to its steady state.A significant amount of work was the development of in-house software to robustly treat the white-light and interferometric image sequences.Two major topics are examined in this work: First, the study of the selection of primary spacing (the microstructure's characteristic size). Second, the in-depth characterization of pattern oscillation, which is a secondary instability of the cellular pattern. The analysis of the results is supported by 3D phase-field simulation, undertaken by the modellers in this team and in the team of Pr. A. Karma (Northeastern University, Boston)
Paris, Johanne. "Etude et modélisation des mécanismes de transfert de matière en ultrafiltration." Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30109.
This study essentially deals with the description and modelling of mass transport phenomena in ultrafiltration. First, according to an experimental study under controlled conditions, various resistances to the mass transfer were underlined and the influence of experimental parameters on the relative importance of each of them was studied. Then, modelling was used in order to predict permeate flux as a function of operating conditions such as initial concentration, mean velocity, transmembrane pressure. In the light of previously published results as well as new experimental results, we discussed the most classical models such as the gel-polarization model, the osmotic pressure model, the resistance-in-series model. No doubt that the first two models are based on deficient assumptions. Moreover, despite several modifications, the resistance-in-series model fails in predicting permeate fluxes. Nevertheless, these models require the knowledge of the mass transfer coefficient k which can be in principle estimated by correlations including Sherwood number. Classical correlations and corrected correlations published were investigated. Due to strong coupling of the transport phenomena (diffusion- convection- high concentration at the membrane surface) close to the membrane, a reliable mass transfer coefficient is difficult to obtain. Thus we have developed a new two-dimensional model based on the numerical resolution of the convective and diffusion equations. This model makes it possible to predict permeate flux according to the operating conditions such as transmembrane pressure, initial concentration, velocity and membrane length. This model was tested using two different solutes and two kind of membranes and good prediction of flux is obtained
Souilem, Inès. "Élaboration de miniémulsions dans un nouveau mélangeur à écoulement élongationnel : influence des paramètres du procédé et de la formulation." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00864095.
Allouane, Tassadit. "Modelisation par la thermodynamique des processus irréversibles du transfert de matière en pervaporation : cas de mélanges liquides complexes." Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30039.
Pervaporation is a membrane process which is of great importance since it makes possible efficient separations which are at once clean and moderate in energy consumption. Up to now the modelling of mass transfer involved is very difficult due to coupling effects between permeants and also between the permeants and the membrane material. In order to rationalize these complex phenomena we develop an approach based on the thermodynamics of irreversible processes(TIP). The pervaporation flux for each component is derived which is a linear function of the driving forces. The phenomenological coefficients involved account for the coupling effects mentioned above. There is neither need of precise knowledge of the transfer mechanisms within the membranes, nor of many difficult experiments. The model can be applied to various binary, ternary and even more complex mixtures, over large variations of the compositions. Phenomenological coefficients can be deduced which are actually independent of the fluxes and driving forces. .
Hameurlaine, Kheira. "Contribution à l'étude d'un arc électrique de faible puissance." Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00821030.
Bernard, Pierre. "Etude du polissage mécano-chimique du cuivre et modélisation du processus d'enlèvement de matière." Ecully, Ecole centrale de Lyon, 2006. http://bibli.ec-lyon.fr/exl-doc/pbernard.pdf.
Chemical Mechanical Polishing (CMP) has benn introduced in semiconductor manufacturing thirty years ago. It makes it possible to obtain fast and high quality planarization at nanometric scales. CMP consists in polishing a chemically modified copper surface with abrasive particules on a polyurethane pad. The chemical transformation of the copper (or other materials) leads to a modification of the mechanical properties of the superficial layer, that is more easily removed. Our study focused firstly on the composition of this modified layer, and secondly on the elaboration of a model that could explain the removal and planarization of the surface layer. We were able to point out that the modified layer is Cu2O. Our model is based on the properties of the pad (roughness, elastic properties), the wafer (mechanical properties of the modified layer) and the abrasive particles (mass concentration, hardness). We established a simple expression between the removal rate (RR), the rotating speed V of the platen and the pressure P applied on the wafer : RR = K. V. P 1,19. Our experimental results corroborate this model. Oour model is also able to explain the planarization phase
Atlan, Samuel. "Modélisation de la libération des composés d'arôme à partir de matrices alimentaires dans des systemes experimentaux et en bouche : détermination des proprietés et mécanismes de transfert de matière." Paris, AgroParisTech, 2007. http://pastel.paristech.org/3444/01/2007-03-19_Th%C3%A8se_Atlan_(version_finale).pdf.
Aroma compounds are volatile molecules which are present in low concentration in food. They are responsible for olfactory perception, and are determinant for organoleptic quality explaining consumer preference. In order to improve the understanding of stimuli generation during food consumption, this work aimed at studying aroma compounds release by modelling mass transfer in real food matrices. The work consisted in two major steps: i) identification of aroma compounds properties ii) analysis of mass transfer, from in vitro systems to in vivo systems (the mouth during food consumption). Knowledge of physicochemical properties is a prerequisite for mass transfer models. The first part of this work thus consisted in their determination. They are divided in two groups: equilibrium properties between two phases (the partition coefficient) and dynamic properties (the diffusion coefficient and the mass transfer coefficient). A new method for processing the experimental data from the PRV (Phase Ratio Variation) was developed for 12 aroma compounds. The partition coefficient varied from 3·10-5 to 3·10-2, coupled with the confidence interval calculation with all the available degrees of freedom. To determine the diffusion coefficient of aroma compounds in complex food matrices, an experimental cell was designed for this purpose, based on the mass transfer simulation, and validated on model matrices. Experimental measurements were then carried out on complex food matrices, allowing the determination of the diffusion coefficients and their variations based on the matrix composition (type of proteins) and the mechanical treatment. The associated confidence interval of the diffusion coefficient was calculated for ethyl hexanoate in different yogurts with various fat and protein ratio. Using a static headspace device, an analysis of the mass transfer mechanisms and its modelling showed that the partition and the diffusion coefficients could be determined simultaneously. The release model was based on ethyl hexanoate in carrageen gels and showed that it is necessary to control the steps of the experimental protocol. Finally, a model of aroma compound release during in vivo consumption was developed. The model takes into account the physicochemical properties of aroma compounds and the physiological properties related to the subject. The model was established for “perfect swallowers”, who close the velopharynx when the product is set in the mouth until the deglutition process. The model allowed the simulation of the release of some aroma compounds (ethyl hexanoate, acetate and butanoate) from the product (yogurt) up to the nasal cavity, and in addition, it was possible to determine the limiting parameters of this release, namely the breathing flow
Chatelain, Christophe. "Modèles de Potts désordonnés et hors de l'équilibre." Habilitation à diriger des recherches, Université de Lorraine, 2012. http://tel.archives-ouvertes.fr/tel-00959733.
Côté, Benoit. "Modèle de vents galactiques destiné aux simulations cosmologiques à grande échelle." Master's thesis, Université Laval, 2010. http://hdl.handle.net/20.500.11794/22281.
Pinsonneault, Steve. "Enrichissement chimique du milieu intergalactique par des vents galactiques anisotropes." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28775/28775.pdf.
Tamain, Patrick. "Etude des flux de matière dans le plasma de bord des tokamaks : alimentation, transport et turbulence." Aix-Marseille 1, 2007. http://www.theses.fr/2007AIX11060.
Particle transport in the edge of tokamaks plays a decisive role both in the center on plasma performances, since it governs the building of density profiles from external particle fuelling, and in the edge on the lifetime of plasma facing components, since it determines particle and energy fluxes reaching the wall. However, this subject has been little explored due to the complexity of modelling the interaction, in the same volume, of the plasma with strong particle, momentum and energy sources and sinks. In the perspective of ITER, the capability of gas puffing systems to reach required density levels without degrading the confinement, as well as the properties of density profiles and flows near the pedestal and in the SOL, remain open questions. This thesis contributes to the effort aiming at giving a better understanding of the mechanisms governing particle fluxes in the edge plasma and their impact on these questions. In a first phase of our work, we present an original approach for the modelling of fuelling by gas puffing, focusing on the thermal impact of the injection on the plasma. On the basis of analytical and numerical models with a reduced number of dimensions, we demonstrate the existence of thermal bifurcations trigerred by the injection and their importance in the dynamics of the neutral penetration and of the plasma relaxation. In the case of Tore Supra, we show that the local cooling linked to a strong injection allows a deeper penetration of particles (r/a = 1. 1 to r/a = 0. 9), but can also lead to a thermal instability of the whole plasma below a given ratio heating power / particle source. The extrapolation of this study for ITER remains pessimistic on the penetration depth of neutrals. However, the sensitivity of the results of these simplified models to the interaction between the parallel and perpendicular directions show that the developpement of numerical tools modelling coherently particle transport in both directions is necessary to progress on these questions. This led to the design of a 3D code presented in the second part of this work. This new tool is a full-torus code, including curvature effects. It solves electrostatic fluid drift equations without scale separation hypothesis, which allows to address with the same tool issues linked to large scale transport as well as micro-turbulence. Two versions of the code have been developped and validated : one treats exclusively closed field lines ; the other, more demanding from the numerical point of view, includes both the Scrape Off Layer (SOL) and the external part of the confined plasma. In a last part, the code is used to address the issue of poloidal asymmetries of parallel flows in the SOL which are observed experimentally but whose origin is not fully clear yet. Simulations reproduce the order of magnitude of measured amplitudes and evidence two different mechanisms which are likely to play a role in this phenomenon, the first at large scales, the other linked to turbulence. The former leans on a coupling between large scale drifts and curvature effects in the SOL while the latter is linked to the ballooning of the radial turbulent flux on the low field side. Finally, the importance of the plasma parallel resistivity on the characteristics of the turbulent transport is analysed as well as the impact of a localized particle injection on the local properties of turbulence
Belkhelfa, Yazid. "Etude du comportement dynamique et du transfert de matière et de chaleur entre des particules sphériques et un écoulement laminaire ou turbulent." Electronic Thesis or Diss., Rouen, INSA, 2008. http://www.theses.fr/2008ISAM0013.
The characterization of flow, mass and heat transfer during moving droplets of diameter inferior to the millimetre makes the object of our study. In the first part, we present the theoretical and experimental knowledge. In the second part, we studied the evaporation of a free falling droplet in the air. In the third part, we make a simulation of the interaction between the spherical particles in laminar flow. This model takes into account the nature of the particle, the Reynolds number and the separation distance. In the last part, we study the dispersion of droplets in a homogeneous and isotropic turbulent flow
Pereda, Jorge. "Formation des microstructures de solidification dans des alliages transparents modèles des alliages métalliques." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0174/document.
The study of solidification microstructure formation is of utmost importance for the design and processing of materials, as solid-liquid interface patterns largely govern mechanical and physical properties. Pattern selection occurs under dynamic conditions of growth. The materials of choice for direct visualization of interface dynamics are transparent organic analogs. On Earth, convection alters the formation of cellular and dendritic microstructures. The micro-gravity of Space is therefore mandatory for fluid flow elimination in bulk samples. Over a hundred days of experiments between 2010 and 2011 were carried out in the DECLIC-DSI, (CNES-NASA) onboard the International Space Station. During the experimental campaign, a huge amount of data, mainly images, was obtained. The objective of this thesis work is to study the dynamics of formation and evolution of the interfacial array, from its birth to its steady state.A significant amount of work was the development of in-house software to robustly treat the white-light and interferometric image sequences.Two major topics are examined in this work: First, the study of the selection of primary spacing (the microstructure's characteristic size). Second, the in-depth characterization of pattern oscillation, which is a secondary instability of the cellular pattern. The analysis of the results is supported by 3D phase-field simulation, undertaken by the modellers in this team and in the team of Pr. A. Karma (Northeastern University, Boston)
Baup, Stéphane. "Elimination de pesticides sur lit de charbon actif en grain en présence de matière organique naturelle : élaboration d'un protocole couplant expériences et calculs numériques afin de simuler les équilibres et les cinétiques compétitifs d'adsorption." Poitiers, 2000. https://tel.archives-ouvertes.fr/tel-00983252.
Hage, Hassan Maya. "Méthodologies de conception optimale de systèmes de conversion électromécanique." Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-01002008.
Jouon, Aymeric. "Hydrodynamique et transport de particules en suspension dans le lagon Sud-ouest de Nouvelle-Calédonie." Toulon, 2007. http://www.theses.fr/2007TOUL0010.
This thesis participates to a study that has been lead for several vears by IRD which aims increased knowledge of hydrodynamics and transport of dissolved substances and particles on the South-west Lagoon of New Caledonia (SLNC). This work stands on field measurements and numerical modelling. The first step of this thesis is an attempt to Synthesise the great amount of data produced by a numerical hydrodynamic model (MARS3D). Indexes having the dimension of time and related to the renewal of water masse Mere computed from numerical Tools applied to the In drodynamic model. The computation methods, the significance and the application of these indexes to the Southwest Lagoon of New-Caledonia (SLNC) are exposed. Examples of application of these indexes aiming to quantity the influence of hydrodynamics on biological processes are shown. Out of flooding periods, the re-suspension of freshly deposited sediments is the main source of suspended particles! on the SLNC. The combined actions of waves and currents induce a bottom shear stress that is responsible for particle re-suspension. In order to access the wave field characteristics, a wave model (WavewatchlII) was implemented over the SLNC. It was \alidated by in situ directional measurements of the wave field. The last part of this thesis focuses on the determination of physical properties of suspended particles such as particle si/e distributions, density, and fall velocit), are compulsory to model particle transport. I his work stands on in situ measurements and laboratory experiences performed with laser particle si/e anal\ser. Results emphasis the importance of bio-aggregation in a coral reef ecosystem
Gardan, Erwan. "Etude des disques externes de galaxies spirales : observation et modélisation de Messier 33." Bordeaux 1, 2007. http://www.theses.fr/2007BOR13474.
Vacassy, Robert. "Synthèse et caractérisations de membranes minérales de nanofiltration : Modélisations du transport de matière et de la perméabilité à l'eau." Montpellier 2, 1996. http://www.theses.fr/1996MON20082.
Zimmermann, Albert. "Simulation du transfert de matière multiconstituant en colonne d'extraction à l'aide d'un bilan de population de gouttes." Toulouse, INPT, 1993. http://www.theses.fr/1993INPT071G.
Abdelmoumni, Lei͏̈la. "Epuration et transfert de matière en réacteur anaérobie membranaire." Montpellier 2, 1996. http://www.theses.fr/1996MON20095.
Majidi, Behzad. "Discrete Element Method Applied To The Vibration Process Of Coke Particles." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29386/29386.pdf.
Physical, mechanical and chemical properties of raw materials have considerable effects on quality of carbon anodes for aluminium smelting process. The present work attempts to investigate the feasibility of application of Discrete Element Method (DEM) simulations in anode production technology. Effects of coke particles shape and size distribution on vibrated bulk density (VBD) of dry coke samples are studied. Coke particles are digitized using two-dimensional and three-dimensional imaging techniques and real-shape particles are used in DEM models of VBD test in Particle Flow Code (PFC). Internal friction coefficient of coke particles were estimated by means of angle of repose tests. Results showed that, as expected, VBD of coke samples is affected by shape and size distribution of the particles. Two-dimensional simulations confirmed that in general, mixed-sized samples have higher VBD than mono-sized cokes and as the fraction of coarse particles increases vibrated bulk density increases. However, existence of 10 wt.% of fine particles to fill the pores between coarse particles is essential. For 3D simulations also, the model follows the trend of experimental data showing that in the container of 2.9 mm diameter, as the content of -4+6 mesh (3.36-4.76 mm) particles increase, VBD increases. It can be concluded that a well-tailored DEM model is capable of predicting the particle rearrangement and density evolution during the vibration process.
Quittau, François. "Vers un comportement de synthèse de particules cohésives par une approche de nanomécanique." Toulouse, INSA, 1996. http://www.theses.fr/1996ISAT0035.
Boichot, Raphael. "Filtration des particules issues des moteurs Diesel par matrices fibreuses plongées dans un champ électrique." Chambéry, 2005. http://www.theses.fr/2005CHAMS008.
The filtration of diesel particulate matter is a major industrial and environmental stake, since the discovery of carcinogenic effects of this kind of particles and the advent of Euro IV (2005) and Euro V (2008-2010) regulations. The aim of this study is to point out the industrial practicability of filtration of this particles by a fibrous media immersed in an electric field. The global shape of this process is a wire-to-cylinder electrostatic precipitator with an porous earth collecting electrode, the whole flow passing through it. It was shown that this process is essentially an agglomerator and not a filter, and that it allows an increase by 50 of the mean diameter of particles. The process, by its completely new and original shape, allows to work with only several millisecondes of residence time. The energetic intensity is so important that the whole volume is compatible with an installation on vehicles. On a technical point of view, the efficiency of this electrostatic agglomerator depends only little on the fibrous matrices or high voltage electrodes used. It is in return very influenced by the quality of electric insulation by ceramic plugs between the canning and high voltage electrodes, and by the discharge polarity. During the last tests with a very optimised agglomerator, we obtain a decrease of 90% in number of the submicronic particulate matter (on a NEDC cycle), with a fuel over-consumption of less than 1%, which corresponds to an "volumic energy” of about 1 Joule per litre. A mathematical model of agglomerator was constructed during this study, integrating the last recent improvements in numeric simulation of Maxwell's equations in presence of space charge, integrating the particle turbulence and taking into account the fractal dimension of diesel aerosol particles. The process is nowadays in an advanced industrialisation stage
Thill, Antoine. "Agrégation des particules : structure, dynamique et simulation : application au cas d'un écoulement stratifié : l'estuaire du Rhône." Phd thesis, Aix-Marseille 3, 1999. http://tel.archives-ouvertes.fr/tel-00109390.
En effet, afin de mener à bien cette étude, il a fallu développer de façon préliminaire différents outils. On a ainsi mis au point deux nouvelles méthodes de mesure expérimentale de la structure des agrégats qui échappent aux techniques existantes. Ces méthodes permettent, outre une meilleure connaissance du système, de développer et de valider un nouveau modèle de la cinétique de croissance des agrégats. Ce modèle numérique prend en compte la dimension fractale des agrégats ainsi que sa variabilité. Il est validé par confrontation à des données issues de la bibliographie et l'expériences.
Une étude de terrain dans l'estuaire du grand Rhône est menée dans des conditions hydrodynamiques contrastées (étiage, débit moyen et crue). Elle a permis d'obtenir, pour la première fois, une série de mesures de tailles de particules tout au long de la zone de mélange. Il est établi que les particules les plus grosses (supérieures à 5 microns) présentent une évolution contrôlée par la dilution, la sédimentation et
éventuellement la remise en suspension. Par contre, les particules plus petites (2 à 5 microns) montrent une augmentation de leur concentration le long de la zone de mélange. Dans les premiers temps du mélange, cette augmentation est liée à la fragmentation d'agrégats. Il est possible de montrer ensuite i) que l'agrégation des colloïdes ne peut expliquer cette augmentation que si ceux ci ne réagissent pas avec les fractions de tailles supérieures et présentent une réactivité très supérieure à la réactivité moyenne (alpha : 0.009) et ii) que la production primaire est un mécanisme probable pour expliquer cette augmentation.
Idoughi, Mohand Laïd. "Extraction de modèles thermiques simplifiés des machines électriques à partir d'un calcul du champ de températures." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00664666.
Benbelkacem, Hassen. "Modélisation du transfert de matière couplé avec une réaction chimique en réacteur fermé." Toulouse, INSA, 2002. http://www.theses.fr/2002ISAT0024.
This work is related to ozone treatment of organic wastes, a gas-liquid reaction. In the first part, a model is proposed for the description of a semi-batch gas-liquid reactor. This model accounts for mass transfer and for irreversible chemical reactions. Using Matlab, the film model is solved and the results are included in the mass balances within the reactor. The 'intermediate regime' is specially studied by introducing a new parameter, the depletion factor D. Associated with the enhancement factor E, it allows the determination of the part of reaction occurring within the film. The second part of this work is specifically related to ozone treatment of organic wastes. Experiments on maleic acid and fumaric acid ozonation are conducted in a bubble column reactor. The rate constants are determined by a trial and error method which compares experimental and numerical results. The ozone fraction reacting within the film is also determined by following the variation of E and D with time
Jamin, Frédéric. "Contribution à l'étude du transport de matière et de la rhéologie dans les sols non saturés à différentes températures." Montpellier 2, 2003. https://tel.archives-ouvertes.fr/tel-00006051.
Druon, Sébastien. "Modélisation et recalage d'objets et d'environnements en déformation viscoplastique : Aide au geste pour les métiers matière." Montpellier 2, 2004. http://www.theses.fr/2004MON20213.
Boissonnat, Philippe. "Étude paramétrique et modélisation des écoulements de la matière par analyse de la distribution des temps de séjour dans trois cuiseurs-extrudeurs bi-vis." Compiègne, 1990. http://www.theses.fr/1990COMPD283.
Jiang, Jian. "Modeling of complex network, application to road and cultural networks." Phd thesis, Université du Maine, 2011. http://tel.archives-ouvertes.fr/tel-00691129.
Yang, Fan. "Modèles topologiques de Majorana Fermions et nouvelles applications." Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX041.
We present a theoretical study of topological models hosting Majorana fermion which is its own anti-particle, with relevant probe of quantum entanglement and experimental protocol for quantum engineering in cQED. In the first part, by proximity effects we address the topological superconducting wire systems, where Majorana fermions emerge as zero-energy modes at edges. By varying strengths of inter-wire couplings and changing fluxes of orbital magnetic fields, we show an interplay between topological p-wave superconductivity and quantum Hall states. For the remaining two parts of the thesis, we focus on Kitaev spin liquids that can be exactly solved in a Majorana fermion representation. We introduce valence bond fluctuations to characterize phase transitions between Abelian and non-Abelian phases, and find a general relation with the entanglement entropy. To simulate these many-body Majorana states, we propose a driven superconducting box circuit with generalizations to coupled box ensembles. There, a variety of models can be implemented including the toric code, the random Ising chain as well as the SYK Majorana model