Dissertationen zum Thema „Chimie – Simulation par ordinateur“
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Beaudré, Anne. „Simulation spatio-temporelle sur ordinateur des processus radiolytiques induits dans l'eau par des electrons“. Toulouse 3, 1988. http://www.theses.fr/1988TOU30182.
Der volle Inhalt der QuelleSchall, Eric. „Contribution numérique à l'étude des écoulements dissipatifs externes hypersoniques : effet du couplage chimie-vibration“. Aix-Marseille 1, 1995. http://www.theses.fr/1995AIX11047.
Der volle Inhalt der QuelleKezic, Bernarda. „Analyse statistique et thermodynamique de la micro-structure dans les émulsions moléculaires“. Paris 6, 2013. http://www.theses.fr/2013PA066749.
Der volle Inhalt der QuelleLes mélanges aqueux diffèrent des mélanges des liquides simples, du fait que les molécules d'eau tendent à s'associer préférentiellement entre elles au travers de la liaison hydrogène, de ce fait ségréguant les molécules de soluté sans pour autant entraîner une démixtion macroscopique des mélanges. Même des mélanges aussi simples que l'eau avec le méthanol exhibent ce type d'ordre local. La micro-hétérogénéité (MH) résultante apparait ainsi comme étant distincte des fluctuations de concentration (CF) qui jouent un rôle important dans la stabilité des mélanges. En établissant la correspondance entre les micro-émulsions et ces mélanges que nous appelons « émulsions moléculaires » à partir de la théorie d'Ornstein-Zernike aux petits vecteurs d'onde, nous montrons comment certains problèmes intrinsèques aux simulations peuvent être résolus en recalculant les corrélations à longue portée. De même, l'introduction des fonctions bridges des corps purs extraits des simulations, permet de mieux comprendre le comportement des équations intégrales pour les mélanges, éclairant en particulier la distinction entre CF et MF
Crevel, François. „Simulations numériques des polymères vivants“. Strasbourg 1, 2007. https://publication-theses.unistra.fr/public/theses_doctorat/2007/CREVEL_Francois_2007.pdf.
Der volle Inhalt der QuelleIn this thesis, we explore the static and dynamical properties of equilibrium polymers, polymers systems being able to cut and recombine themselves, in three and two dimensions. We confirmed recents results about Flory's ideality hypothesis in dense regime in three dimensions and mesured the effects of of this correction on equilibirum polymers. We also studied the dynamic of scission et recombination et showed the existence of the predicted regime of controled diffusion. In the two dimensional systems, we show measure ment of critical exponents predicted in recent theories
Crevel, François Wittmer Joachim Baschnagel Jörg. „Simulations numériques des polymères vivants“. Strasbourg : Université Louis Pasteur, 2007. http://eprints-scd-ulp.u-strasbg.fr:8080/859/01/CREVEL_Francois_2007.PDF.
Der volle Inhalt der QuelleJoulia, Xavier. „Simulation des procédés chimiques en régime permanent : formulation et convergence“. Toulouse, INPT, 1987. http://www.theses.fr/1987INPT021G.
Der volle Inhalt der QuelleHaroun, Mohamed Fahim. „Simulation numérique de l'activation du méthane sur la surface (111) du nickel idéale et avec un adatome“. Université Louis Pasteur (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/restreint/theses_doctorat/2007/HAROUN_Mohamed_Fahim_2007.pdf.
Der volle Inhalt der QuelleHaroun, Mohamed Fahim Légaré Pierre Maamache Mustapha. „Simulation numérique de l'activation du méthane sur la surface (111) du nickel idéale et avec un adatome“. Strasbourg : Université Louis Pasteur, 2008. http://eprints-scd-ulp.u-strasbg.fr:8080/00000932.
Der volle Inhalt der QuelleVincent, Stéphane. „Modélisation de l'allumage en milieu turbulent avec chimie complexe“. Rouen, 1997. http://www.theses.fr/1997ROUES049.
Der volle Inhalt der QuelleRottereau, Manuel. „Agrégation, percolation et séparation de phase d'une assemblée de sphères dures browniennes adhésives : approche par simulation hors réseau“. Le Mans, 2005. http://cyberdoc.univ-lemans.fr/theses/2005/2005LEMA1003.pdf.
Der volle Inhalt der QuelleThe complex fluids form a class of materials exhibiting a large originality in their static and dynamic properties which results from the chemical structure of the constituting elementary particles and their spatial organization in particular on mesoscopic scales. These systems often involve phenomena of aggregation, gelation and/or phase separation due to the interactions between their constituents. The objective of this thesis is to understand and model the formation of these structures and their way of filling the space by monitoring these processes by computer simulations. These simulations are based on off-lattice hard spheres models which can mimic for example an assembly of spherical micelles in attractive or repulsive interactions
Coupez, Bernard. „Etudes théoriques de la complexation et de l'extraction de cations uranyles et lanthanides par des molécules bidentates : Effects chélate et de synergie“. Université Louis Pasteur (Strasbourg) (1971-2008), 2004. http://www.theses.fr/2004STR13114.
Der volle Inhalt der QuelleTran, Huong-Lan. „Numerical modelling of natural convection of binay mixtures : case of a helium buoyant jet in an air-filled enclosure“. Paris 6, 2013. http://www.theses.fr/2013PA066379.
Der volle Inhalt der QuelleThis study focuses on the understanding of the dispersing and mixing mechanisms of helium in air in a semi-confined cavity. This phenomenon is an example of a low-density fluid injected in a high-density ambient fluid which results in a buoyant plume. This is an important safety issue for all hydrogen-based systems. A numerical model has been developed combining the appropriate boundary conditions with the conservation equations for the mixture mass, species mass, momentum and the state law of the mixture as well as the variation laws of the physical properties. First a laminar starting plume of a glycerol-water mixture is considered as a validation test-case by comparison with experimental data [Rogers & Morris 09]. The propagation of the axisymmetric buoyant-jet is modeled for large Grashof numbers and small injection Reynolds numbers. A good agreement has been found for the ascent velocity as well as the two types of head shape. A modified scaling law of the ascent velocity versus a modified Reynolds number is proposed to take into account for the kinetic viscosities of both fluids. For the helium-air mixture, a 2D planar air-filled cavity was first considered. The auto-similar scaling laws for steady plane plumes in unconfined environment [Gebhart et al. 88] have been reproduced for the vertical velocity and the density profiles along the vertical centerline, when considering moments before the plume impact on the top wall. Then a cylindrical container is considered to model the CEA experiment [Cariteau & Tkatschenko 12]. Numerical results are compared to experimental data and to a numerical benchmark. The effect of the axisymmetry assumption is evidence
Doyon, Julien. „Simulation numérique d'agrégats fractals en milieu de microgravité“. Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28588/28588.pdf.
Der volle Inhalt der QuelleKireeva, Natalia. „Ensemble QSPR modeling of stabilities of metal : ligands complexes and melting points of ionic liquids“. Strasbourg, 2009. http://www.theses.fr/2009STRA6008.
Der volle Inhalt der QuelleBabu, Sujin Nicolai Taco Gimel Jean-Christophe. „Propriétés statiques et dynamiques de sphères dures attractives étude par simulation numérique /“. [S.l.] : [s.n.], 2008. http://cyberdoc.univ-lemans.fr/theses/2008/2008LEMA1001.pdf.
Der volle Inhalt der QuelleDeutsch, Emmanuel. „Dispersion de particules dans une turbulence homogène isotrope stationnaire calculée par simulation numérique directe des grandes échelles“. Ecully, Ecole centrale de Lyon, 1992. http://bibli.ec-lyon.fr/exl-doc/TH_T1454_edeutsch.pdf.
Der volle Inhalt der QuelleArnold, Céline. „Formation de films minces polymères à partir de nanocolloides composites“. Strasbourg, 2009. http://www.theses.fr/2009STRA6038.
Der volle Inhalt der QuelleThis thesis focuses on the formation of waterborne polymer films and is part of the integrated European project Napoleon (NAnostructured waterborne POLymEr films with OutstaNding properties). Two main topics were investigated: the drying mechanisms and the distribution of the surfactant in the latexes and the dry films. The effect of some relevant physicochemical parameters (composition, size of the particles, pH of the latex) has been studied on a range of homogeneous and composite (containing a mineral filler: laponite or montmorillonite) acrylic latexes stabilized with sodium dodecyl sulphate (SDS). The surface of the dry films was investigated by atomic force microscopy (AFM) and by X-ray photoelectron spectroscopy (XPS). The bulk of the films was investigated during drying by magnetic resonance profiling (MRP) and in the dry state by confocal Raman spectroscopy in order to obtain essentially the distribution of the surfactant. A model based on the transport and the diffusion of the surfactant during drying has been developed to explain the formation of SDS aggregates in the films. Finally, Monte Carlo simulation was used to study the adsorption/desorption of the surfactant at the water/particle interface in a drying latex
Fourches, Denis. „Modèles multiples en QSAR/QSPR : Développement de nouvelles approches et leurs applications au design "in silico" de nouveaux extractants de métaux, aux propriétés ADMETox ainsi qu'à différentes activités biologiques de molécules organiques“. Université Louis Pasteur (Strasbourg) (1971-2008), 2007. http://www.theses.fr/2007STR13119.
Der volle Inhalt der QuelleThis thesis work concerns the improvement of prediction performances of QSAR structureproperty models, using consensus modelling strategies based on fragment descriptors, and also, to their applications for « in silico » design of metal binders, ADMETox properties and different biological activities of organic compounds. In the first part, some important concepts and methodologies of chemoinformatics are described. In the second part, the ensemble of programs ISIDA (In Silico Design and Data Analysis) is introduced. During this thesis work, two consensus approaches have been suggested: the « Divide and Conquer » strategy and the Stepwise k- Nearest Neighbors approach. Applications of new strategies lead to significant improvement of predictions accuracy, compared to the conventional models. In the third part, all ISIDA methods have been successfully applied to model various chemical and biological properties. Experimentally proven predictions demonstrate the robustness of the methods
Augoula, Steve. „Conception et analyse de schémas d'ordre élevé pour l'approximation des équations de Hamilton-Jacobi du premier ordre“. Bordeaux 1, 2000. http://www.theses.fr/2000BOR10599.
Der volle Inhalt der QuelleThe propagation of a flame front in streaked medium can be seen as a particular case of a first order Hamilton Jacobi mixed problem. It acts like a system coupling a version of the well-known eikonal equation, Dirichlet boundary conditions and a state constraint. The aim of this thesis is to develop and analyse new numerical high order schemes for the approximation of general first order Hamilton Jacobi equations. And finally to simulate, thanks to these latter methods, the evolution of solid propellant combustion. The first part characterizes and analyses the Hamilton Jacobi systems stemming from the modelisation of the phenomenon. In particular, a proof of the existence and uniqueness is given in the viscosity sense. The second part is devoted to the approximation of standard Cauchy problems related to general first order Hamilton Jacobi equations. The numerical solutions are approached by new high order methods which are stabilized by innovator filters. The new schemes are valided by several numerical experiments giving k-th order convergence rate when the piecewise polynomials of degree k function are used, measured in L¹-norm
Bellec, Steve, und Steve Bellec. „Simulation et optimisation des rhéogrammes d'usines d'extraction de l'or par cyanuration“. Doctoral thesis, Université Laval, 2012. http://hdl.handle.net/20.500.11794/23881.
Der volle Inhalt der QuelleL’or, en raison de sa rareté et de ses nombreuses applications, est l’un des métaux les plus convoités. Il est principalement recherché pour sa valeur monétaire élevée qui a d’autant plus subi une hausse importante au cours des dernières années. Cette hausse de la valeur de l’or a grandement contribué à modifier le visage des nouveaux projets aurifères mis de l’avant en permettant à plusieurs compagnies d’exploiter des gisements à faibles teneurs ou contenant des minerais difficiles à traiter. Une chute drastique du prix de l’or aurait un impact important sur la rentabilité de ces nouveaux projets. L’une des façons de minimiser ce risque est de cibler une optimisation économique des circuits de cyanuration. Ce projet propose d’optimiser les circuits de cyanuration de l’or par simulation en basant son raisonnement sur la caractérisation de l’accessibilité des surfaces d’or. Pour ce faire, on caractérise cette accessibilité et on exploite ensuite l’information obtenue pour modéliser les différentes étapes d’un circuit conventionnel d’extraction de l’or par cyanuration. Lors de l’étape de broyage, les particules aurifères sont fragmentées pour libérer les surfaces d’or. Étant donné la grande différence de densité entre l’or et la gangue, cette libération a un impact considérable sur la classification gravimétrique des particules. Finalement, lors de l’étape de lixiviation, l’accessibilité des surfaces facilite l’attaque de l’or par le cyanure en présence d’oxygène et joue un rôle primordial sur l’optimisation du circuit. Pour créer des modèles représentatifs, il est essentiel d’avoir en main des données cohérentes et justes. Sans une bonne qualité de données, la calibration et même l’identification de la structure d’un modèle peuvent être faussées. Dans le cas des minerais aurifères, la nature intrinsèque du minerai et les difficultés associées à l’analyse des concentrations en or dans les phases liquides et solides peuvent entraîner des mesures non représentatives de la population globale à caractériser. La première étape de ce projet de recherche consiste donc à explorer l’application de la réconciliation de données aux procédés d’extraction de l’or. Ceci permet de rendre cohérentes les données issues de campagnes industrielles d’échantillonnage et de créer des modèles représentatifs de fragmentation, de classification et de lixiviation. La vitesse de cyanuration est fortement dépendante du degré de libération de l’or et par conséquent de la taille des particules aurifères. Il est donc important d’identifier dans quelle classe granulométrique se trouvent les grains d’or dans le minerai. Le premier modèle proposé dans ce projet permet de caractériser la distribution de l’or dans les différentes classes granulométriques ainsi que son accessibilité. Ceci est effectué en combinant un modèle de libération cubique et un modèle de broyage qui fait intervenir des fonctions de broyage et de sélection différentes pour les particules porteuses d’or et celles de gangue. Le modèle proposé est calibré et validé sur une série d’essais de broyage effectués en laboratoire. La classification gravimétrique influence différemment le partage des particules mixtes, d’or libre et de gangue entre la surverse et la sousverse d’hydrocyclones. Étant donné que les particules mixtes et d’or libre ont des degrés d’accessibilité différents et, par conséquent, des cinétiques de lixiviation différentes, la classification influence la performance des circuits de cyanuration positionnés en aval d’hydrocyclones. On propose donc de coupler le degré d’accessibilité, obtenu par le modèle de broyage, au modèle de Plitt à l’aide de la densité des particules. En bref, selon que l’or est totalement libéré ou attaché à une particule de minerai, son comportement en classification est différent puisqu’il est influencé par la densité de la particule. Le modèle développé est ensuite appliqué à des données industrielles. Pour ce faire, il est cependant nécessaire de faire intervenir un second modèle puisqu’une cyanuration a lieu à l’intérieur des broyeurs de ce circuit. Un modèle simplifié permettant de caractériser la lixiviation de l’or simultanément à la fragmentation du minerai est donc proposé. L’information relative au degré d’exposition des surfaces d’or alimente un modèle phénoménologique de cyanuration. Le modèle intègre les concepts d’exposition et de diffusion tout en tenant compte de la stœchiométrie de la réaction de dissolution de l’or et de la consommation du cyanure par les cyanicides. Des essais en laboratoire sont utilisés pour confirmer la prédominance de la réaction diffusionnelle dans le processus de cyanuration industriel. Ces essais sont également utilisés pour calibrer et valider le modèle proposé. L’ensemble des modèles développés est regroupé dans un simulateur d’usine couplant l’accessibilité des surfaces d’or à sa dissolution. À cette fin, les modèles développés pour des conditions discontinues sont adaptés à une application continue. Finalement, le simulateur est utilisé pour étudier différents scénarios d’optimisation économique de circuits de cyanuration. Les modèles développés et les résultats obtenus sont encourageants et permettent de jeter les bases d’une approche reliant l’accessibilité des surfaces au broyage, à la classification gravimétrique et à la cyanuration de l’or.
Gold, because of its rarity and its various applications is one of the most coveted metals. It is mainly known for its high value that has significantly increased recently. This increase in the value of gold contributed to change the face of new gold projects by allowing companies to exploit low grade deposits or difficult ore to process. A drastic fall in the price of gold would have a significant impact on the profitability of these new projects. One way to minimize this risk is to focus on economic optimization of cyanidation circuits. This project proposes to optimize gold cyanidation circuits with simulation based on the characterization of gold surfaces accessibility. To do so, gold accessibility is characterized. The information is then use to model the different stages of a conventional cyanidation gold extraction circuit. During the grinding step, the gold particles are broken to liberate gold surfaces. Given the high density difference between gold and the non-value minerals, liberation has a significant impact on the gravimetric classification. Finally, during leaching, the accessibility of surfaces facilitates the attack of gold by cyanide in presence of oxygen. This latest link is used to optimize leaching circuits. To create representative models, it is essential to have consistent data. With poor data quality, calibration, and even model structure may be distorted. In the case of gold ores, the intrinsic nature of the ore and the difficulties associated with gold concentration measurements in the liquid and solid phases can lead to non-representative data sets of the ore to characterize. Therefore, the first step of this research project is to explore the data reconciliation application to gold extraction processes measurements. This corrects data from industrial sampling campaigns and allows creating representative models of fragmentation, classification and leaching. Cyanidation kinetic is highly dependent of the degree of gold liberation and consequently is dependant on ore particle size. It is therefore important to identify in which ore size class the gold grains are. The first model proposed in this project characterizes the distribution of gold in different size classes as well as its accessibility. This is done by combining a cubic liberation model and a grinding model that uses different breakage and selection functions for mixed and non-value particles. The proposed model is calibrated and validated on a series of laboratory grinding tests. The gravimetric classification influences differently mixed particles, free gold and free non-value particles partition to the overflow and underflow of hydrocyclones. Liberated gold grains and gold attached to mixed particle have different classification behavior because they are influenced by the density of the particle. Furthermore, mixed particles and liberated gold grains have different degrees of accessibility and different leaching kinetics. Consequently, classification as an influence on cyanidation circuits performances positioned downstream of hydrocyclones. It is therefore proposed to link the information on the degree of gold accessibility obtained by the grinding model to Plitt’s classification model by using particle density. The model is then applied to industrial data. To do so, it is however necessary to introduce a second model since cyanidation takes place inside the mills of this grinding circuit. A simplified model for characterizing the gold leaching simultaneously with the fragmentation of the ore is proposed. Information on the exposure of gold surfaces feed a phenomenological model of cyanidation. The model incorporates the concepts of exposure and diffusion while taking into account the stoichiometry of gold dissolution reaction and cyanide consumption by cyanicides. Laboratory tests are used to confirm that the reaction rate is limited by diffusion in the industrial cyanidation process. These tests are also used to calibrate and validate the proposed model. All the models developed are grouped in a simulator combining the degree of gold surface accessibility to gold dissolution. To this end, the models developed for batch conditions are adapted for continuous application. Finally, the simulator is used to study different scenarios of cyanidation circuit economic optimization. The models developed and the results obtained lay the foundations to integrate liberation to grinding, gravity classification and cyanidation of gold.
Gold, because of its rarity and its various applications is one of the most coveted metals. It is mainly known for its high value that has significantly increased recently. This increase in the value of gold contributed to change the face of new gold projects by allowing companies to exploit low grade deposits or difficult ore to process. A drastic fall in the price of gold would have a significant impact on the profitability of these new projects. One way to minimize this risk is to focus on economic optimization of cyanidation circuits. This project proposes to optimize gold cyanidation circuits with simulation based on the characterization of gold surfaces accessibility. To do so, gold accessibility is characterized. The information is then use to model the different stages of a conventional cyanidation gold extraction circuit. During the grinding step, the gold particles are broken to liberate gold surfaces. Given the high density difference between gold and the non-value minerals, liberation has a significant impact on the gravimetric classification. Finally, during leaching, the accessibility of surfaces facilitates the attack of gold by cyanide in presence of oxygen. This latest link is used to optimize leaching circuits. To create representative models, it is essential to have consistent data. With poor data quality, calibration, and even model structure may be distorted. In the case of gold ores, the intrinsic nature of the ore and the difficulties associated with gold concentration measurements in the liquid and solid phases can lead to non-representative data sets of the ore to characterize. Therefore, the first step of this research project is to explore the data reconciliation application to gold extraction processes measurements. This corrects data from industrial sampling campaigns and allows creating representative models of fragmentation, classification and leaching. Cyanidation kinetic is highly dependent of the degree of gold liberation and consequently is dependant on ore particle size. It is therefore important to identify in which ore size class the gold grains are. The first model proposed in this project characterizes the distribution of gold in different size classes as well as its accessibility. This is done by combining a cubic liberation model and a grinding model that uses different breakage and selection functions for mixed and non-value particles. The proposed model is calibrated and validated on a series of laboratory grinding tests. The gravimetric classification influences differently mixed particles, free gold and free non-value particles partition to the overflow and underflow of hydrocyclones. Liberated gold grains and gold attached to mixed particle have different classification behavior because they are influenced by the density of the particle. Furthermore, mixed particles and liberated gold grains have different degrees of accessibility and different leaching kinetics. Consequently, classification as an influence on cyanidation circuits performances positioned downstream of hydrocyclones. It is therefore proposed to link the information on the degree of gold accessibility obtained by the grinding model to Plitt’s classification model by using particle density. The model is then applied to industrial data. To do so, it is however necessary to introduce a second model since cyanidation takes place inside the mills of this grinding circuit. A simplified model for characterizing the gold leaching simultaneously with the fragmentation of the ore is proposed. Information on the exposure of gold surfaces feed a phenomenological model of cyanidation. The model incorporates the concepts of exposure and diffusion while taking into account the stoichiometry of gold dissolution reaction and cyanide consumption by cyanicides. Laboratory tests are used to confirm that the reaction rate is limited by diffusion in the industrial cyanidation process. These tests are also used to calibrate and validate the proposed model. All the models developed are grouped in a simulator combining the degree of gold surface accessibility to gold dissolution. To this end, the models developed for batch conditions are adapted for continuous application. Finally, the simulator is used to study different scenarios of cyanidation circuit economic optimization. The models developed and the results obtained lay the foundations to integrate liberation to grinding, gravity classification and cyanidation of gold.
Babu, Sujin. „Propriétés statiques et dynamiques de sphères dures attractives : étude par simulation numérique“. Le Mans, 2008. http://cyberdoc.univ-lemans.fr/theses/2008/2008LEMA1001.pdf.
Der volle Inhalt der QuelleThis thesis deals with the study of the structure and the dynamics of attractive spheres. For this purpose a new simulation technique called the Brownian cluster dynamics (BCD) was introduced. With BCD we can relax the system by cooperative cluster relaxation and can also study the effect of bond rigidity. The method was compared with Event Driven Brownian Dynamic simulations which gave the same static and dynamic properties. Using zero interaction range we were able to suppress phase separation and thereby to study the slow dynamics of strongly attracting spheres. The results disproves the existence of so-called attractive glasses proposed in the literature. By introducing rigid bonds we suppressed crystallization for short range interaction which allowed us to study the kinetics of phase separation and more specifically the inter play between phase separation and gelation. As we distribute bonds between nearest neighbors we were able to trace out two kinds of percolation lines as a function of volume fraction and interaction strength : the bond percolation and the contact percolation. We also studied the effect of flexibility of bonds on irreversible aggregation. Even though the structures created by flexibly bonded diffusion limited cluster aggregation were locally quite dense they showed fractal behavior at large length scales. Tracer diffusion was studied in gels formed by irreversible aggregation of hard spheres. It was found that the diffusion coefficient is determined by the accessible volume, i. E. The volume available to the centre of mass of the tracer. We put forward a phenomenological equation connecting the diffusion coefficient and the accessible valid for different gel structures and tracer sizes
Fortin, Camille. „Etudes par simulations numériques et moléculaires de la réactivité atmosphérique de l'iode“. Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R053.
Der volle Inhalt der QuelleDuring a severe accident occurring to a pressurized nuclear water reactor, radiological consequences are related to the transport and deposition of radionuclides released into the environment. Following the Fukushima Daiichi accident, significant differences between measurements and simulations were observed for iodine deposition. It could notably be explained by the absence of any iodine chemistry in the IRSN dispersion codes. To address this, a mechanism of atmospheric iodine chemistry involving 257 reactions was developed from a critical review of the literature. In parallel, missing thermokinetic data were determined by molecular-scale simulations for the X + H2O2 (X = Br, I) and OH + CH2IOH reactions. 0D and 3D simulations were performed using ASTEC and Polair3D after an injection of either I2 or CH3I. The results showed a partial and rapid transformation of these iodinated gaseous compounds. The influence of several parameters (air quality, quantity and nature of iodine released) on iodine speciation was evaluated. For all simulations, iodine is quickly found in the form of iodine oxides and nitroxides or gaseous iodocarbon compounds. The latter may be the cause of iodinated aerosols formation and deposition
Coelho, Daniel. „Génération, géométrie et propriétés de transport de milieux granulaires“. Poitiers, 1996. http://www.theses.fr/1996POIT2346.
Der volle Inhalt der QuelleCerbelaud, Manuella. „Hétéroagglomération de suspensions céramiques : une étude numérique“. Limoges, 2008. https://aurore.unilim.fr/theses/nxfile/default/265324bc-02ff-4c5b-ab85-07aada762eb8/blobholder:0/2008LIMO4024.pdf.
Der volle Inhalt der QuelleHeteroagglomeration in ceramic dilute suspensions composed of alumina and silica has been studied by means of two simulation methods : Brownian dynamics and global minimization. First, simulationswere applied to a system, inwhich alumina and silica particles have similar sizes. They allowed to analyze the composition and the structure of the agglomerates. Then, simulations were adapted to a second system, where the silica particles are sixteen times smaller than those of alumina. In this case, simulations showed that the silica particles adsorb on alumina and that the strongly charged alumina particles agglomerate via the silicawhich is placed between them. These agglomerates are very elongated although their equilibrium shapes are more compact. The experimental observations obtained in both systems are in agreement with the simulation results
Araujo, Filho Moacyr Cunha de. „Circulations de Langmuir et turbulence sous une houle cisaillée par le vent“. Toulouse, INPT, 1996. http://www.theses.fr/1996INPT019H.
Der volle Inhalt der QuelleFremont, Hélène. „Test de circuit intégrés par faisceau d'électrons : étude de la mesure de potentiel à travers les couches isolantes“. Bordeaux 1, 1988. http://www.theses.fr/1988BOR10579.
Der volle Inhalt der QuelleFelder, Christophe. „Transport d'une solution saline en cellule de Hele-Shaw : expériences et simulations numériques“. Vandoeuvre-les-Nancy, INPL, 2003. http://www.theses.fr/2003INPL067N.
Der volle Inhalt der QuelleTo study the spatio-temporal evolution of a miscible and non-reactive contaminant into a saturated porous media, a laboratory mode! (a transparent Hele-Shaw cell) was developed. The carrying out of the experimental set-up, the plates are made of optical glass, allowed to elaborate a global and non-intrusive method to measure concentration in the mixing zone. This method is based on light absorption properties by dye marking injected solution
Zhong, Guoming. „Contribution à l'étude de l'adsorption dans une colonne : modélisation et simulation numérique“. Compiègne, 1991. http://www.theses.fr/1991COMPD373.
Der volle Inhalt der QuelleIbănescu, Liliana. „Programmation par règles et stratégies pour la génération automatique de mécanismes de combustion d'hydrocarbures polycycliques“. Vandoeuvre-les-Nancy, INPL, 2004. http://www.theses.fr/2004INPL031N.
Der volle Inhalt der QuelleThe primary objective ofthis thesis is to explore the approach ofusing rule-based systems and strategies, for a complex problem of chemical kinetic: the automated generation of reaction niechanisms. The thesis presents the basic concepts of the chemical kinetics, the chemical and computational problems related to the conception and validation of a reaction mechanism, and gives a general structure for the generator of reaction mechanisms called Ga sEl. The representation of the chemical species uses the notion of molecular graphs, encoded by a term structure called GasEI terms. The chemical reactions are expressed by rewriting roles on molecular graphs, encoded by a set of conditional rewriting roles on GasEI terms. The strategies language of the ELAN system is used to express the reactions chaining. Qualitative chemical validations are presented for acyclic and polycyclic molecules
Latouche, Gaétan. „Évaluation des teneurs de radionucléides dans le milieu aqueux en aval de la Centrale Nucléaire Gentilly-2“. Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25311/25311.pdf.
Der volle Inhalt der QuelleDuboc, Bastien. „Modélisation hybride de la chimie pour la simulation numérique de la combustion“. Thesis, Normandie, 2017. http://www.theses.fr/2017NORMIR23/document.
Der volle Inhalt der QuelleEven if significant progress is being made to improve the power of high-performance computers, the numerical simulation of reactive flows involving complex chemistry is still a challenging task. The objective of this work is the development of the Hybrid Transported-Tabulated Chemistry method (HTTC), designed for the DNS/LES simulations of flames with detailed kinetic mechanisms, with an acceptable cost. This novel approach combines the transport of the main species in the flow with the tabulation of the radical species. It has been implemented in a DNS/LES code and validated on 1D methane and kerosene flames. The cost of the simulations has been considerably decreased, compared to classic detailed chemistry solvers. Then, simulations of methane edge flames, featuring large gradients of mixture fraction, have been performed with HTTC. In particular, the impact of the methods used to extend the chemical tables and to compute the control variables have been analyzed in details. A very good agreement has been found by comparison with detailed chemistry
Hoonakker, Frank. „Graphes condensés de réactions, applications à la recherche par similarité, la classification et la modélisation“. Université Louis Pasteur (Strasbourg) (1971-2008), 2008. https://publication-theses.unistra.fr/restreint/theses_doctorat/2008/HOONAKKER_Frank_2008.pdf.
Der volle Inhalt der QuelleThis work is devoted to the developpement of new methods of mining of chemical reactions based on the Condensed Graph of Reaction (CGR) approach. A CGR integrates an information about all reactants and products of a given chemical reaction into one 2D molecular graph. Due to the application of both conventional (simple, double, etc. ) and dynamical (single to double, broken single, etc. ) bond types, a CGR ”condenses” a reaction (involving many molecules) into one pseudo-molecule. This formally allows one to apply to CGRs the chemoinformatics approaches earlier developed for individual compounds. Three possible applications of CGRs were considered: – unsupervised classification of reactions based on clustering algorithms; – reactions similarity search, and – Quantitative Structure Reactivity Relationships (QSRR). Model calculations performed on four databases containing from 1 000 to 200 000 reactions demonstrated high efficiency of the developed approaches and software tools. An system for optimizing reactions condition has been designed, and patented in the USA
Hilka, Martin. „Simulation numérique directe et modélisation de la pollution des flammes turbulentes“. Châtenay-Malabry, Ecole centrale de Paris, 1999. http://www.theses.fr/1998ECAP0640.
Der volle Inhalt der QuelleRogaume, Thomas. „Caractérisation expérimentale et modélisation de l'émission de polluants lors de l'incinération des déchets ménagers“. Poitiers, 2001. http://www.theses.fr/2001POIT2296.
Der volle Inhalt der QuelleThe aim of this study concernes the emissions of the pollutants, principally the NOx, during the incineration of the municipal solid wastes. A mixture of wood, cardboard and plastics is used to simulate the combustible part of the municipal wastes. The objective of the work is the optimisation of the techniques of reduction of the emissions of NOx and the development of a kinetic model of their formation. Two experimental set-ups are used : a counter flow fixed bed reactor and a tubular furnace. The fixed bed reactor permits to simulate the combustion process observed in an industrial furnace. The tubular furnace permits to study the thermal degradation of our combustibles (wood, cardboard, PET and polyamid). A program have been developed to simulate the chemical process of combustion taking place into the fixed bed reactor. It uses a detailed kinetic mechanism with a simple physical model. The agreement obtained between the experimental and the theoretical emissions is very good
Serrière, Mickaël. „Modélisation des processus de transformation des dispersoi͏̈des dans un alliage d'aluminium 3003 : influence de la description des équilibres thermodynamiques locaux“. Vandoeuvre-les-Nancy, INPL, 2004. http://www.theses.fr/2004INPL058N.
Der volle Inhalt der QuelleA precipitation model is developped for a multicomponent alloy, in particular for 3003 aluminium alloy and multiphase precipitation during industrial thermal treatment. This model handle the evolution of the particle size distribution during different thermal treatments, either simple thermal treatment as isothermal holdings or more complex ther- mal treatment as industrial homogenisation treatment. Ln this way, the model is coupled to an equilibrium thermodynamic calculation software called Thermo-Calc. Ln a first time, we have studied the influence of the different description parameters which enter the model, then we have studied the influence of the way the equilibrium is thermodynamically described. Ln a second time, the modelling results are compared to experimental ones obtained in the frame of the VirCast project. Those results leads to satisfaying qualitative comparisons but do not permit quantitative comparisons. Ln order to enhance the results, the model must be coupled to an homogenisation model
El, Mir Hafid. „Comportement de l'arc électrique et fusion de l'électrode consommable dans un four de refusion VAR“. Vandoeuvre-les-Nancy, INPL, 2005. http://www.theses.fr/2005INPL040N.
Der volle Inhalt der QuelleThe present study is aimed to improve our knowledge of the electric arc in the Vacuum Arc Remelting VAR process, as weil as characterize the cathode melting stage. The first step consisted in investigating, thanks to an experimental modulus, the behaviour of the electric arc during the remelting of zirconium alloys, for various operating conditions. High speed video camera observations have put in evidence the influence of the cathode tip shape and the effect of applying an external magnetic field on the movement of the clusters of cathode spots. Besides, infrared thermography measurements show qualitatively that the electrode height thermally affected by the arc is very sm ail and depends on the melt rate. The goal of the second part of this work is the development of a numerical model to simulate the motion of clusters of spots at the tip of the cathode. Coupling this approach with the simulation of the behaviour of a plasma jet emitted by a single cluster, previously established in LSG2M, enables calculating the power distribution at the VAR ingot top as a function of process parameters (current, electrode geometry and external magnetic field). Ln a third step, a thermal model of the consumable electrode during melting has been written, assuming a 2D axisymmetrical geometry. Using the operating parameters as model inputs, it predicts in particular the melting rate value and evolution of the cathode tip shape. The model was validated through simulating the three successive remeltings of a zirconium alloy, following an industrial processing route
Rodríguez, Román Carlos Manuel. „Analyse statistique des équations d'évolution : application à la redistribution de la turbulence en écoulements entre plaques“. Toulouse, INPT, 1997. http://www.theses.fr/1997INPT028H.
Der volle Inhalt der QuelleDemenay, Aurélien. „Estimation des sensibilités des matériaux énergétiques soumis à divers stimuli. Interprétation de la sensibilité à l’aide de mécanismes cinétiques détaillés“. Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLY007.
Der volle Inhalt der QuelleThe main aim of this work is to elaborate predictive tools allowing sensitivity estimation of energetic materials submitted to various stimuli. The main work concerns the calculation of targeted properties of materials having a probable effect on sensitivity predictions. Especially the physico-chemical properties, the thermodynamic properties and properties related to electrostatic potential of the molecule. Prediction is done using correlations established for impact, shock wave, electrostatic discharge, thermal stress and friction. The results are overall good given the current limitations on the subject. Especially there is a lack of quality experimental data and methods for physico-chemical property calculations of energetic materials.The second aim of this work is the study of a potential link between the sensitivity and the auto-ignition delay of energetic materials. Checking this hypothesis requires the development and the use of detailed kinetic mechanisms for a variety of compounds having different sensitivities (RDX, HMX, TNT, TNAZ, NG, PETN, FOX-7, NTO, CL-20). Writing series of reactions, the estimation of rate constants and the calculation of thermodynamic data were carried out. The experimental data available do not allow to validate the mechanisms which must be also improved. At this time it is not possible to assess or not this hypothesis even if trends are such as to confirm it. However, this approach needs to be further worked out
Neji, Mejdi. „Modélisation chimie mécanique et simulation numérique du comportement expansif de résines échangeuses d’ions enrobées dans une matrice cimentaire“. Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10106/document.
Der volle Inhalt der QuelleIon exchange resins (IER) are widely used in the nuclear industry to purge non directly storable infected effluents. IER then become a solid waste which could be stored as any classical nuclear waste. One way of conditioning consists in embedding it into a cement paste matrix. This process raises some concerns regarding the cohesiveness of the composite. Once embedded, the IER might indeed interact with the cement paste which would lead, in some cases, to the swelling of the composite. This thesis has been set up to address this potential issue, with the aim to develop a numerical tool able to predict the mechanical behavior of this kind of material. This work only focuses on the long term behavior and more specifically on the potential degradations of the cement paste /IER composite due to cationic IER
Vincent-Bonnieu, Sébastien. „Simulation et modélisation multiéchelles de la rhéologie des mousses 2D“. Phd thesis, Université de Marne la Vallée, 2006. http://tel.archives-ouvertes.fr/tel-00165161.
Der volle Inhalt der QuelleUn premier fil conducteur est le couplage entre les échelles macroscopique, mésoscopique et locale. Nous montrons que l'allongement d'un film individuel sous l'effet d'une déformation macroscopique suit une nouvelle loi qui permet de modéliser l'élasticité des mousses 2D en fonction de la microstructure. Par ailleurs, nous discutons comment un écoulement
macroscopique résulte de réarrangements de bulles agissant comme des dipôles de force au sein d'un milieu continu élastique.
Un second fil conducteur est le couplage entre rhéologie et vieillissement. A l'aide de la représentation dipolaire, nous établissons une loi analytique décrivant la déformation induite par les réarrangements dus au vieillissement. Sur cette base, nous formulons un modèle rhéologique constitutif prenant en compte la dynamique intrinsèque due au vieillissement, et les contraintes géométriques et topologiques.
Costa-Cabral, Benedito José. „Étude de la structure des liquides moléculaires à l'aide de simulations du type Monte-Carlo : Applications à la modélisation des effets de solvant“. Nancy 1, 1985. http://www.theses.fr/1985NAN10864.
Der volle Inhalt der QuelleElmonser, Lassaad. „Simulation de procédés de gravure par faisceau ionique assistée chimiquement des matériaux III-V“. Nantes, 2006. http://www.theses.fr/2006NANT2090.
Der volle Inhalt der QuelleThis project is carried out under RMNT contract of research ministry and in collaboration with Elvion Veeco, LPN and Alcaltel OPTO+. It concerns the development of 2D etching model of GaAs by Ar+/Cl2 using chemically assisted ion beam etching process (CAIBE). This model allows to study the etching rate and the etch profile evolution in time and space as a function of the experimental conditions of CAIBE machine. The 2D etching model takes into account of several local surface phenomena such as the neutral reflection on the surface elements, the shadowing effects of neutrals and ions, the angular dependence of sputtering yield and mask erosion. Good agreements between the simulation results and the experiments have been obtained. This affirms that our model can be considered as a good tool to predict the etch profile evolution for the optoelectronic applications
Jaouen, Nicolas. „An automated approach to derive and optimise reduced chemical mechanisms for turbulent combustion“. Thesis, Normandie, 2017. http://www.theses.fr/2017NORMIR03/document.
Der volle Inhalt der QuelleComplex chemistry is an essential ingredient in advanced numerical simulation of combustion systems. However, introducing detailed chemistry in Computational Fluid Dynamics (CFD) softwares is a non trivial task since the time and space resolutions necessary to capture and solve for a flame are very often smaller than the turbulent characteristic scales by several orders of magnitude. A solution based on the reduction of chemical mechanisms is proposed to tackle this issue. An automated reduction and optimisation strategy is suggested relying on the construction of reference trajectories computed with the evolution of stochastic particles that face mixing, evaporation and chemical reactions. The methodology, which offers strong reduction in CPU cost, is applied to the derivation of several mechanisms for canonical and industrial applications, for simple fuel such as methane up to more complex hydrocarbon fuels, as kerosene, including an optimised lumping procedure for isomers
Truc, Olivier. „Prediction of chloride penetration into saturates concrete - multi-species approach“. Toulouse, INSA, 2000. http://www.theses.fr/2000ISAT0019.
Der volle Inhalt der QuelleAchir, Samira. „Etude des mécanismes de stabilisation des protéines par spectroscopie Raman et dynamique moléculaire“. Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10022/document.
Der volle Inhalt der QuelleThe mechanisms of protein stabilization in solution and dry state have been investigated in this thesis. New therapeutic approaches are developing from many therapeutic biomolecules related to advances in recombinant DNA technology. Although we are not able to use them because of their low stability. The latter is improved in the dry state albeit freeze-drying gets a source of stress for many proteins. This work has mainly focused on the stability of model proteins, by in-situ Raman micro-spectroscopy during freeze-drying. The analysis identified the origin and the process of denaturation and the structural transformations of the inherent protein freeze-drying. Raman mapping was implemented at different stages of drying cycle, leading to the description of the protein/solvent/co-solvent interactions and decrypting the protein stabilizing mechanisms during the whole freeze-drying process. The protein stability was also analyzed during accelerated aging, by using several biopreservers. It revealed that the bioprotective efficiency of trehalose is enhanced by adding a small amount of glycerol. Molecular dynamics simulations were also carried out on trehalose-glycerol glassy matrices and the plasticizing / anti- plasticizing effects of the residual water were studied
He, Longting. „Etude des phénomènes d'allumage : applications aux mélanges H2/O2“. Aix-Marseille 1, 1991. http://www.theses.fr/1991AIX11377.
Der volle Inhalt der QuelleWafo. „Déchloration catalytique des PCB (polychlorobiphényles) : optimisation et approche mécanistique de la réaction“. Aix-Marseille 1, 1996. http://www.theses.fr/1996AIX11032.
Der volle Inhalt der QuelleLauvaux, Thomas. „Inversion à méso échelle des sources et puits de carbone“. Versailles-St Quentin en Yvelines, 2008. http://www.theses.fr/2008VERS0007.
Der volle Inhalt der QuelleLes méthodes d'inversion à grande échelle ont permis d'estimer la variabilité spatiale des sources et puits de carbone continentaux mais les incertitudes associées restent importantes. En e_et, les concentrations atmosphériques intègrent la variabilité des _ux de surface, mais les modèles de transport à basse résolution utilisés dans les inversions ne peuvent reproduire correctement la complexité da la dynamique atmosphérique locale des sites de mesure. Cependant, ces estimations sont plus représentatives de la grande hétérogénéité spatiale des écosystèmes que les mesures directes des _ux. Les méthodes inverses et directes qui visent toutes les deux à estimer le bilan des échanges de carbone entre la surface et l'atmosphère s'appliquent donc à des échelles di_érentes et sont ainsi di_cilement comparables. Au cours de cette thèse, un système d'inversion à méso échelle a été développé pour corrigerles _ux de carbone à une résolution de 8km. Le modèle de transport à haute résolution (MésoNH) a permis de simuler la variabilité des concentrations atmosphériques avec une meilleure précision, ce qui a permis de limiter les incertitudes sur les _ux inversés. L'intégralité des données est issue de la campagne régionale intensive CERES de mai et juin 2005, lors de laquelle plusieurs tours instrumentées ont mesurées les concentrations et les _ux de CO2 dans le Sud Ouest de la France. Des mesures aéroportées ont permis également d'observer les concentrations en altitude ainsi que les _ux de CO2 aggrégées sur de larges bandes à la surface. Dans un premier temps, la capacité du système à corriger les _ux de CO2 a été estimé par l'intermédiaire de pseudo-données. La majeure partie de la variabilité des concentrations a été attribuée aux _ux régionaux dans une zone qui s'étend, selon les conditions météorologiques, jusqu'à 300km autour des sites de mesure. Dans un second temps, un ensemble de simulations a permis de dé_nir les structures spatiale et temporelle des erreurs de transport. Dans un dernier temps, les _ux corrigés par l'inversion à 8km de résolution ont été comparés à des mesures directes de _ux. Le système d'inversion a été ainsi validé dans le temps et l'espace et a montré une amélioration de l'estimation des _ux de CO2 issues d'un modèle de végétation en diminuant signi_cativement les erreurs initiales par rapport aux observations indépendantes de _ux de CO2
Creazzo, Fabrizio. „Oxygen evolution reaction at cobalt oxides/water interfaces : heterogeneous electrocatalysis by DFT-MD simulations & metadynamics Ab initio molecular dynamics study of an aqueous NaCl solution under an electric field Ionic diffusion and proton transfer in aqueous solutions of alkali metal salts Ionic Diffusion and Proton Transfer in Aqueous Solutions under an Electric Field: State-of-The-Art Ionic diffusion and proton transfer of MgCl2 and CaCl2 aqueous solutions: an ab initio study under electric field DFT-MD of the (110)-Co 3 O 4 cobalt oxide semiconductor in contact with liquid water, preliminary chemical and physical insights into the electrochemical environment Enhanced conductivity of water at the electrified air–water interface: a DFT-MD characterization Ions tune interfacial water structure and modulate hydrophobic interactions at silica surfaces“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASE012.
Der volle Inhalt der QuelleIn this thesis, DFT-MD simulations, coupled with state-of-the-art metadynamics techniques, are applied to gain a global understanding of Co3O4 and CoO(OH) cobalt oxide aqueous interfaces in catalyzing the oxygen evolution reaction (OER), and hence possibly help in the design of novel catalysts basedon non-precious materials, a current key field of research in science and technology, especially of importance for the hydrogen economy, for green technology in a period of time with an ever more growing demand in green-energy. In this thesis, we step-by-step reveal the OER mechanisms on spinel Co3O4 andCoO(OH) cobalt aqueous electrocatalysts carefully and rationally via novelmetadynamics techniques.Up to now, the literature has never taken into account the atomistic modifications on the electrode structure as well as on the interfacial water into their modeling of OER processes. Such lack of knowledge clearly represents a significant hurdle toward the development of improved catalysts, which couldbe overcome by employing methods able to track the catalytic features of theOER at the atomistic scale. For the first time, we show how important itis to take into consideration the presence of the liquid water environment inthe structural characterization of catalyst surfaces, i.e. for (110)-Co3O4 and(0001)-CoO(OH) in this work. A detailed characterization of chemical andphysical properties of the aqueous interfaces is provided (i.e. structure, dynamics, spectroscopy, electric field), for the (110)-Co3O4 and (0001)-CoO(OH)aqueous surfaces.A study of the OER is presented not only by looking at the catalysts, butalso by addressing the role of the water environment in the catalytic process,not done before in literature. Accordingly, both gas-phase and liquid-phaseOER are here investigated at the (110)-Co3O4 and (0001)-CoO(OH) adoptinga novel enhanced sampling metadynamics approach able to address a widerange of chemical reaction mechanisms and to fully include the role of thesolvent degrees of freedom, allowing to unveil reaction networks of remarkablecomplexity. The energetics, kinetics and thermodynamics behind the OER aretherefore found at these cobalt oxide surfaces
Cinar, Éric. „Structure et dynamique dans les solutions aqueuses d'urée et d'acétone : étude par simulation de dynamique moléculaire“. Lille 1, 2006. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2006/50376_2006_164.pdf.
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