Дисертації з теми "Études de dissolution"
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Mirabelli-Bakaya, Sylviane. "Le rôle de la faute dans la dissolution du mariage en droit français et en droit italien." Lyon 3, 2004. http://www.theses.fr/2004LYO33005.
Повний текст джерелаGosselin, Léa. "Trajectoires de satisfaction conjugale et dissolution d'union." Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26000.
Повний текст джерелаSandré, Anne-Laure. "Nouveau procédé de dissolution-précipitation pour l’exploitation de minerais nickélifères oxydés par voie hydrométallurgique : études cinétiques, modélisation et calcul de réacteurs." Thesis, Paris, ENMP, 2012. http://www.theses.fr/2012ENMP0037.
Повний текст джерелаThe goal of this thesis is to build a predictive model for a continuous industrial unit combining simultaneously nickel ore dissolution and iron precipitation. A two steps method was used. First experiments in batch or semi-batch reactors were done in order to understand and model separately the different phenomenon that take place. Then all the equations and associated constants were used to build a model. This work allowed some advances both on the system studied and on the methods used. First thermodynamics of Na-Fe(III)-H2SO4 solutions in the 70-100°C temperature range was clarified and natrojarosite solubility constant Na0,84H0,16Fe2,90(SO4)2(OH)5,7 was deduced. Secondly parameters acting on sodium and potassium jarosite precipitation were highlighted and their growth kinetics were deduced through an original use of caracterisctics method. Then ore dissolution kinetics were found, taking into account different ores phases and their granulometry. After deducing all the necessary parameters, an original model allowing to simulate a cascade of dissolution/precipitation reactors with recyling loop was build and validated. This conception tool, coupled with a technico-economic study allows the optimisation of such a process
Heisbourg, Guillaume. "Synthèse, caractérisation et études cinétiques et thermodynamique de la dissolution de ThO2 et des solutions solides Th1-xMxO2 (M=U, Pu)." Paris 11, 2003. https://tel.archives-ouvertes.fr/tel-00005511.
Повний текст джерелаThe goal of this work is to study the aqueous corrosion resistance of ThO2 and Th(1-x)MxO2 (M = U, Pu) ceramics, within the framework of direct storage of potential nuclear fuels in deep geological site. These solids were synthesized by precipitation in oxalic medium, calcined at high temperature then characterized by various analytical techniques: XRD, SEM, TEM, XPS, XAS, PIXE, MASE. The structural characterization of the solids showed that ail the synthesized mixed oxides are homogeneous solid solutions. The optimization of sintering conditions of ThO2 and Th(1-x)UxO2 solid solutions was studied in order to obtain sintered pellets with the highest experimental density. At last, the dissolution study of these ceramics was undertaken in several aqueous media (HNO3, HCl, H2SO4, natural waters) versus several chemical parameters, varying independently in order to determine the kinetics law of dissolution. In a general way, the leaching rate of Th(l-x)UxO2 solid solutions increases ail the more than the molar fraction U/Th+U is increasing. Dissolution process is governed by the relative importance of the process described by the dissolution rate of the solid and the oxidation rate of uranium. The concentration of dissolved actinides is controlled at first by dissolution kinetics then by the solubility of secondary phase (ThO2, nH2O) when the saturation of the leachate is reached. In order to compare the resistance of these solids with respect to the dissolution with those of other materials, normalized leaching rates were extrapolated with pH = 5. 5 and 90ʿC. The normalized dissolution rates obtained are approximately 10^(-8) g. M^(-2). J^(-1) for ThO2 and Th(0,87)Pu(0. 13)O2 and 10^(-6) g. M^(-2). J^(-1) for Th(0,76)U(0,24)O2. These normalized dissolution rates are low compared to those of ceramics currently studied within the framework of the specific conditioning matrices
Heisbourg, Guillaume. "Synthèse, caractérisation et études cinétique et thermodynamique de la dissolution de ThO_2 et des solutions solides Th_(1-chi)M_(chi)O_2 (M=U,Pu)." Phd thesis, Université Paris Sud - Paris XI, 2003. http://tel.archives-ouvertes.fr/tel-00005511.
Повний текст джерелаBelbey, Salim. "Formation, effets et dissolution du mariage en droit international privé algérien et comparé : étude des conflits de lois." Thesis, Paris 2, 2019. http://www.theses.fr/2019PA020001.
Повний текст джерелаFormation, Effects and Dissolution of Marriage in Algerian and Comparative Private International Law: Study of Conflicts of LawsAbstract: The marriage, object of this study, is not submitted in its entirety to a single law. One distinguishes traditionally between its formation, its effects and its dissolution. Algerian private international law subjects the basic conditions of marriage to the jurisdiction of the national law of the spouses and the form, to one of the following laws : the law of the place of celebration, the law of the common domicile, the common national law or the law governing the substantive rules. The effects of marriage are governed by the national law of the husband at the time of the conclusion of the marriage; the dissolution is, in turn, subject to the national law of the husband assessed at the time of the initiating act. The elaboration of the conflict rules as well as the exact qualification of certain conditions of validity of the marriage are not enough to be able to affirm that the conflicts are settled; because the law, designated as competent by the national conflict rules, can be overridden in favor of another. Next to public order, which is the most well-known reason and whose conception varies from one country to another, there is the case of the dismissal and the case of the fraud with the law. The comparison made here between the Algerian, Egyptian and French systems reveals that, although these systems have a common language, that of private international law, this language has a different emphasis in the first two systems because of the religious nature of the domestic law of marriage. The originality of these two systems resides in the fact that they establish the Muslim religion and the privilege of nationality as connecting factors in matters of personal status. It is thus that the solutions of the conflicts of laws relating to the formation, the effects and the dissolution of the marriage, become more delicate
El, Masri Sarah. "Low transition temperature mixtures based on cyclodextrins as solubilizing vehicles in pharmaceutical preparations." Electronic Thesis or Diss., Littoral, 2024. https://documents.univ-littoral.fr/access/content/group/50b76a52-4e4b-4ade-a198-f84bc4e1bc3c/BULCO/Th%C3%A8ses/Toxicologie/122040_EL_MASRI_2024_archivage.pdf.
Повний текст джерелаSolubility enhancement is a critical aspect in the formulation and development of novel drug molecules. To overcome challenges associated with poor solubility, formulation scientists have explored numerous strategies, among them the use of cyclodextrins and cosolvents. The latter approach is a simple and effective method, where organic solvents are used to enhance the solubility of poorly water-soluble compounds. In recent years, deep eutectic solvents (DESs) have emerged as a cheap and green alternative to organic solvents, showing great promise for the solubilization of hydrophobic molecules. More recently, DESs based on cyclodextrins (CDs) have been introduced under the name "supramolecular deep eutectic solvents" (SUPRADESs). Cyclodextrins (CDs) are cage molecules renowned for their ability to enhance the solubility and stability of drug molecules entrapped inside their cavity.This study aimed to evaluate the potential of DESs and SUPRADESs for use in pharmaceutical preparations. To this end, a panel of selected DESs and SUPRADESs were first prepared and characterized. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) demonstrated that the solvents are liquid over a broad temperature range and stable up to 100°C. Density and viscovity measurements showed that DESs' properties can be tuned depending on their composition. Infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies provided evidence of hydrogen bonds formation in the prepared solvents. Further, the solubility and stability of a series of poorly water-soluble active pharmaceutical ingredients (APIs) were evaluated. The solvents displayed significant solubility enhancement and good stability after a year of storage. In addition, the effect of water addition on the solubilizing potential was evaluated. These experiments highlighted the advantage of using SUPRADESs over DESs, since they were revealed to be more resistant to dilution effect. This was attributed to the formation of CD/API inclusion complex, as proved by NMR studies. Finally, drug release experiments showed that the use of DESs and SUPRADESs resulted in increased dissolution rates compared to the solid drug. Overall, these findings support the potential of DESs and SUPRADESs for being used as solubilizing vehicles in phamaceutical formulations
Somali, Kossi. "Le parlement dans le nouveau constitutionnalisme en Afrique : essai d'analyse comparée à partir des exemples du Bénin, du Burkina Faso et du Togo." Phd thesis, Université du Droit et de la Santé - Lille II, 2008. http://tel.archives-ouvertes.fr/tel-00288063.
Повний текст джерелаCadoré, Eric. "Mécanismes de dissolution du quartz dans les solutions naturelles : étude expérimentale et modélisation." Toulouse 3, 1995. http://www.theses.fr/1995TOU30251.
Повний текст джерелаChabert, Anne-Marie. "Étude de la clarification des fines de dissolution des combustibles nucléaires irradiés." Châtenay-Malabry, Ecole centrale de Paris, 1991. http://www.theses.fr/1991ECAP0723.
Повний текст джерелаMarc, Philippe. "Étude de réactions hétérogènes autocatalytiques : application à la dissolution du dioxyde d’uranium." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0382/document.
Повний текст джерелаDissolution is a milestone of the head-end of hydrometallurgical processes used for recycling spent nuclear fuel. The solubilization of the chemical elements is essential before performing the liquid-liquid extraction steps to separate reusable material and final waste. This study aims at better understanding the chemical, physico-chemical and hydrodynamic phenomena of uranium dioxide dissolution reactions in nitric medium. This study is also part of a modeling approach aiming at expressing the intrinsic reaction rates and describing of the physico-chemical phenomena at interfaces. Optical microscopy confirmed the highly autocatalytic nature of the reaction and led to measurements, for the very first time, of "true" chemical kinetics of the reaction. The acid attack of sintering-manufactured solids occurs through preferential attack sites. It develops cracks in the solids that can lead to the cleavage of the solid. This inhomogeneous attack is made possible by the establishment of bubbling in the cracks which allows periodic renewal of the reagents and thus maintains the reaction within the cracks. This point is a key component of the mechanism: a strong link between the development of cracks, bubbling through the cracks, and overall dissolution kinetics is demonstrated in this work. Finally, a model coupling material balance to the structural evolution of the solid and liquid phase compositions, and taking into account the interfacial transport is proposed. The simulations based on this model are close to the experimental observations, and allow to reproduce for the very the first time the effect of various reaction parameters, such as the reduction of overall kinetics when turbulence increases
Grisenti, Martine. "Étude de l'hydrodynamique et des transferts en cuve agitée par microjets." Toulouse, INPT, 1991. http://www.theses.fr/1991INPT046H.
Повний текст джерелаGauthier, Pascale. "Formulation de microsphères de principes actifs en rotogranulation : étude de divers excipients." Clermont-Ferrand 1, 1995. http://www.theses.fr/1995CLF1PP01.
Повний текст джерелаPrud'homme, Nathalie. "Cristallisation-dissolution de GaPO₄ : phénomènes à l'interface cristal-solvant. Étude de la dissolution contrôlée de GaPO₄ pour la réalisation de résonateurs piézoélectriques à haute fréquence." Montpellier 2, 2005. http://www.theses.fr/2005MON20138.
Повний текст джерелаPollet-Villard, Marion. "Évolution de la surface réactive du feldspath potassique au cours de son altération en contexte géothermal : étude expérimentale et modélisation." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAH015/document.
Повний текст джерелаThis thesis aims at quantifying the reactive surface area evolution of dissolving K- feldspar, and evaluating the impact on the dissolution kinetics during its alteration in geothermal context. The study focuses on : (1) the influence of secondary coatings on the orthoclase surface, (2) the impact of the anisotropic crystalline structure of orthoclase and (3) the effect of etch pit formation on the mineral surface. Experimental and numerical results highlight that the orthoclase dissolution rate and its evolution over time mainly depends onits morphology. Some orthoclase faces dissolve 10 times faster than others, resulting in an increase of the surface proportion of rapid vs. slow dissolving faces during the process and the increase of up to an order of magnitude of the overall orthoclase dissolution rate. These results question the significance of rate laws and reaction mechanisms determined from powder experiments and the pave to new approaches for investigating mineral reactivity
Benioug, Marbe. "Étude numérique de la croissance microbienne en milieu poreux." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0104/document.
Повний текст джерелаMathematical modeling of transport in porous media of organic chemical species in the presence of a bacterial population growing in the form of biofilms is an important area of research for environmental and industrial applications such as the treatment and the remediation of groundwater contaminated by organic pollutants. Biofilms, which are composed of bacteria and extracellular organic substances, grow on the pore-walls of the porous medium. Biodegradable organic solutes are converted into biomass or other organic compounds by the bacterial metabolism. This evolution of the microbial biomass phase within the porous medium is a complex process due mainly to growth (or decay) and spatial spreading of the cellular phase. Processes such as biofilm sloughing and attachment (or detachment) of cells from the fluid phase may also contribute to the biofilm volume variation. In this context, the aim of the thesis is to focus on the mechanisms that control the development of biofilms in porous media and its impact on the hydrodynamic properties of the porous matrix. The objective of this work is to model this pore-scale phenomenon of biofilm growth by integrating the various mechanisms which favor the bacterial development (bacterial proliferation, assimilation of nutrients to synthesize new cellular materials, attachment of cells) or, conversely, which are responsible for slowing down (e.g., detachment of cells, toxicity). An IB-LB model is developed for flow calculation and non-boundary conforming finite volume methods (volume of fluid and reconstruction methods) are used for reactive solute transport. A sophisticated cellular automaton model is developed to describe the spatial distribution of bacteria. Several numerical simulations have been performed on complex porous media and a quantitative diagram representing the transitions between the different biofilm growth patterns was proposed. Finally, the bioenhanced dissolution of NAPL in the presence of biofilms was simulated at the pore scale. The impact of biosurfactants and NAPL toxicity on bacterial growth has been investigated
Sonaglio, Diva. "Développement de systèmes multiparticulaires par extrusion/sphéronisation : étude physico-chimique et pharmacotechnique de sphéroi͏̈des à base de polymères cellulosiques." Montpellier 1, 1996. http://www.theses.fr/1996MON13511.
Повний текст джерелаLembezat-Real, Valérie. "Les dissolutions du lien familial en droit comparé franco-espagnol." Bordeaux 1, 1994. http://www.theses.fr/1994BOR1D018.
Повний текст джерелаAfter franco spain made an attempt to catch up with europe. Their law tried to be in keeping with european law. Only the fiel of marriage and especially the methods of dissolution of the wedlock has still preserved the print of spanish civilization. First of all de point is to study the dissolution of marriage based on previous or concomiting facts at the moment when marriage was conclued : invaliditeies. In the first part, we'll try to consider the contents of the notion of marriage. The debaded, ambiguous spanish system, the contents of in the laws of the two countries. Then, we'll lay the stress on the existence of marriage dissolution founded on posterior facts: separation and divorce. Three ideas are to be stresses : the special place of separation in spanish law, the idea of democracy tied with the notion of divorce, the child's advantage in divorce procedure
Besseyrias, Alain. "Dissolution coulométrique de toles d'acier galvanisé allié : étude des mécanismes et amélioration de la technique d'analyse." Grenoble INPG, 1995. http://www.theses.fr/1995INPG0111.
Повний текст джерелаPachon-Rodriguez, Edgar-Alejandro. "Étude de l’influence de la dissolution sous contrainte sur les propriétés mécaniques des solides : fluage du plâtre." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10284/document.
Повний текст джерелаThe huge enhancement of the creep of plasterboard by humid environments is an old problem in the building industry, but its origin remains unknown. To understand this mechanism a three scales study (macro : mechanical behavior, micro : dissolution kinetics, nano : atomic observation) has been done. There is a strong correlation between wet plaster creep and gypsum dissolution kinetics. The concordance between this correlation and the law of deformation by pressure solution, well-known in geology, permits to propose pressure solution as one of the mechanisms responsible of wet plaster creep. The topological evolution of the cleaved surface of a gypsum single crystal during its dissolution in a flowing under-saturated aqueous solution has been observed with an atomic force microscope. The kinetics of step migration strongly depends on the saturation state of the solution, the force applied by the tip on the surface, as well as the used additives. The study of the influence of the force applied by the tip on the step velocity evidence two different dissolution enhancement regimes. At high forces (> 15 nN) a corrosive wear behavior is observed, while at low forces (< 10 nN) pressure solution is the observed mechanism. The step velocity evolution with the force obeys the known kinetic law of pressure solution
Pachon-Rodriguez, Edgar. "Étude de l'influence de la dissolution sous contrainte sur les propriétés mécaniques des solides : fluage du plâtre." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00697835.
Повний текст джерелаAl, Azzi Patricia. "Formation et dissolution du mariage en droit international privé libanais, étude à la lumière du droit français." Rennes 1, 2011. http://www.theses.fr/2011REN1G044.
Повний текст джерелаThe contribution of the Lebanese law to private international law of marriage is original due to the particular structure of the Lebanese nation. Lebanon possesses an original and specific system related to its history and the Lebanese society is a pluralistic society constituted of different communities, having each its tradition, its beliefs, and its own organization. This pluralism impregnates the various structures of the state, based on the balance of representation of communities. It reflects as well through its legal system, which seeks to preserve the identities of communities, essentially in matters of personal status where the traditional attributions of religious authorities are recognized by the state and assured by civil efficiency. This religious and cultural pluralism allows considering the issue of the conflict of laws in private international law both in the formation and the dissolution of marriage, as well as in the complex relations between law and religion. This implies the richness that the study of the Lebanese inter-communitarian law can reveal to private international law within this field
Sallek, Brahim. "Les phosphates de calcium, supports potentiels de médicaments implantables : étude de leurs mécanismes de dissolution et d'adsorption." Toulouse, INPT, 1993. http://www.theses.fr/1993INPT058G.
Повний текст джерелаGarzón, Losik Germán Alexander. "Étude et modélisation d’un procédé de dissolution poussée en réacteur continu – application aux oxydes (U, Pu)O₂." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0050.
Повний текст джерелаPlutonium multirecycling aims to stabilise the plutonium inventory and eventually close the fuel cycle in France. This action involves the reprocessing and recycling of plutonium-rich Mixed OXide (MOX) spent fuel, which implies the adaptation of current technologies, in particular dissolution. Therefore, an experimental study of the reaction between uranium-plutonium mixed oxides and nitric acid coupled with chemical reactor modelling is required. In this context, a study of the dissolution of three mixed oxides (30, 40, and 65% Pu/(U+Pu)) and plutonium dioxide in nitric acid is carried out using an optical setup. It can be highlighted that the mixed oxide dissolves according to a similar mechanism as plutonium dioxide when the plutonium content in the solid exceeds 30%. Moreover, only the mixed oxide with the highest uranium content undergoes an autocatalytic reaction mechanism similar to that identified for uranium dioxide. A dissolution model describing the size evolution of a single particle against time was developed. Such model considers the description of particles surface by a fractal geometry approach as well as the surface where the reaction actually takes place. Model was validated by comparison of experimental data from this work and from literature. In addition, a second model was developed, taking into account the single particlemodel, based on population balance equations. The model allows to describe the behaviour of a fluidised bed dissolver, which presents interesting advantages for solid-fluid type reactions. Finally, by implementing the developed model, simulations were performed showing a first estimation of the feasibility of a new dissolution process for current and upcoming MOX fuels
Moriceau, Brivaëla. "Étude de la dissolution de la silice biogénique des agrégats : utilisation dans la reconstruction des flux de sédimentation de la silice biogénique et du carbonne dans la colonne d'eau." Brest, 2005. http://www.theses.fr/2005BRES2034.
Повний текст джерелаThe dramatic increase of carbon concentration in the atmosphere is limited by the action of some oceanic areas that act like a “sink of carbon” mainly thanks to the biological pump. Because of the strong participation of diatoms to the primary production and their ability to aggregate, we study the role of diatoms and the impact of aggregation on the biological pump. Laboratory experiments determined that the BSiO2 dissolution rate of aggregated cells is lower than the one of freely suspended cells. The model of aggregate used to better understand aggregate internal parameters that provoke the decrease of the dissolution rate, confirmed that the dissolution is lower in aggregates and added that the DSi diffusion in aggregate is lower than in seawater. The decrease of the BSiO2 dissolution rate is attributed to the strong DSi concentrations measured into aggregates and to the higher viability of aggregated cells. Experimental results were then combined with in situ measurements of BSiO2 fluxes in nine areas cf the ocean, intc a simple model that reconstruct BSiO2 fluxes in the water column. This model allows to calculate the repartition of the BSiO2 between large particles and freely suspended cells and to better understand particles dynamic. The BSiO2 fluxes reconstructed using the model, were then associated with a relation between Si/C ratios and water column depth to determine the real importance of diatoms in the biological pump cf carbon. We then calculated the carbon fluxes at the maximum depth of the mixing layer. The use of the Si fluxes as a proxy of the carbon fluxes allow to ignore difficulties due to the cornplexity of the carbon chemistry. The role of diatoms in the export and transfer of carbon strongly depend on the way used to calculate the export out of the surface layer
Stockmann, Gabrielle J. "Étude expérimentale de la carbonatation du basalte." Phd thesis, Université Paul Sabatier - Toulouse III, 2012. http://tel.archives-ouvertes.fr/tel-00712597.
Повний текст джерелаRong, Yi. "Formation du sulfate de calcium hémihydrate de type α à partir de gypse par un procédé de dissolution-cristallisation : étude cinétique expérimentale et modélisation". Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM070/document.
Повний текст джерелаIn mineral or pharmaceutical industry, many transformations of solids in solution (polymorphic or not), take place by the dissolution of the first solid and the crystallization of the second solid. Instead of the traditional drying process, the conversion of gypsum (calcium sulfate dihydrate) to alpha-bassanite (calcium sulphate hemihydrate) can be carried out in aqueous solution by increasing the temperature sufficiently. At this moment, the gypsum becomes more soluble in water than the hemihydrate, which then has the possibility to crystallize. An apparatus and an original procedure have been designed to investigate the sensitivity of the kinetics of transformation and the characteristics of the hemihydrate crystals obtained under its operating conditions. In fact, this dissolution-recrystallization route allows to control the aspect ratio of the hemihydrate crystals, and even their average size and size dispersion, by the choice of its physicochemical conditions such as temperature, pH, use of additives, and seeding the solution with the appropriate hemihydrate particles. Image analysis techniques are developed to identify the aspect ratio of the particles.A kinetic model taking into account the dissolution of gypsum, the nucleation and the growth of calcium sulphate hemihydrate and their equilibrium in aqueous phase and solubility had been developed and the equations of this model are solved with the help of MATLAB software. Coupled with a numerical optimization method, this resolution under MATLAB makes it possible to examine the validity of the assumptions on the selected processes and to identify their kinetic parameters
Ahoulou, Assohoun Wilfried. "Étude expérimentale du transport réactif en milieu poreux : application à la dissolution couplée à des gradients de masse volumique." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0172.
Повний текст джерелаPredicting the instabilities triggered by the chemical reaction of a percolating fluid passing through soluble rock is a major scientific challenge for many fields of application (formation of karstic systems, fracture evolution, acid stimulation of oil wells or CO2 sequestration and storage). Indeed, the dissolution of the solid matrix often leads to the appearance and development of channels, called wormholes, which modify the hydrodynamic characteristics (permeability and porosity) of the crossed medium. The objective of this thesis is to study, through an experimental laboratory program, the influence of the variation of the physical properties of the percolating fluid and in particular the variation of its density on the configuration of the wormholes. In other words, the coupling between chemical and hydrodynamic instabilities induced by density contrast is studied. In a first step, the experimental program is based on the interpretation of images acquired during the injection of pure water ("acid" phase) in a saline massif ("soluble" rock) reconstituted in 2D via a Hele-Shaw type cell and considering different injection configurations. In a second step, the use of X-ray tomography allowed to approach these effects in a 3D configuration consisting of specimens of salts dissolved by under-saturated salt solutions. Whatever the studied configuration, the experimental results suggest that the dissolution regimes can still be described by the two classical adimensional numbers, namely the Damköhler and Péclet numbers. The regime diagram is not very sensitive to variations in density contrast, especially for relatively strong Péclet and weak Damköhler numbers, but suffers a slowing down of the propagation of the dissolution front when the Richardson number (ratio of gravitational and convective effects) increases. The analysis of morphological descriptors such as volume, dissolved/undissolved zone interface, tortuosity and pore size distribution shows that the density contrast has a non-negligible influence on the dissolution regimes for medium to strong Richardson. Some of our experimental results were confirmed by two-dimensional numerical simulations conducted with COMSOL Multiphysics® software
Verlaguet, Anne. "Fluides métamorphiques et transfert de matière : approche expérimentale et étude des veines de haute pression-basse température de Vanoise." Paris 11, 2006. http://www.theses.fr/2006PA112152.
Повний текст джерелаDuring orogenesis, large quantities of aqueous fluid are produced by dehydration metamorphic reactions. Metamorphic veins can be considered as traces of this fluid in rocks. Two major questions arise: (1) are metamorphic veins the result of external fluid circulations in open systems, or resulting from local interaction between the rock and the dehydrating fluid in a closed system? (2) Is Al an immobile element because of its low solubility? We realized both a petrologic study of karstic metabauxites from Vanoise (French Alps) and an experimental study (tube-in-tube setup) coupled to thermochemical modeling of fluid-mineral interactions. Experiments show that Al is a mobile element in metamorphic processes, and is preferentially transferred to secondary phases due to its low solubility. However, the amount of Al-rich phases precipitated in response to P, T or stress fluctuations is insufficient to explain the abundant crystallizations observed in veins. In Vanoise, several generations of veins are observed: they result from closed system interactions between the rock and the fluid produced along dehydration reactions (13-16 % of rock volume) and do not require external fluid circulations. Some vein crystallizations correspond to the products of metamorphic reactions. Pressure-solution mechanisms in high-stress zones can drive preferential dissolution of minerals with high molar volume. The nature of nucleation sites and the energies of fluid-mineral interfaces can potentially drive selective mineral transfer towards veins
Ghazal, Ghassan. "Etude de la propreté inclusionnaire des lingots VAR - Application aux alliages de titane." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL016N/document.
Повний текст джерелаThe presence of exogeneous inclusions has always been a major concern for the titanium industry. To help improve the inclusional cleanliness of VAR (Vacuum Arc Remelting) titanium ingots, a numerical and experimental study was undertaken.The numerical model is capable of predicting the motion and dissolution of a hard-α defect falling from the electrode tip into the ingot melt pool during vacuum arc remelting. It is implemented in SOLAR, a CFD code that simulates the ingot growth and solidification. The dissolution of the inclusion is governed by nitrogen diffusion from the defect towards the surrounding molten metal. A model describing this phenomenon predicts the particle size evolution and the nitrogen profile at each moment. The motion of the spherical particle is tracked using a Lagrangian model and the influence of turbulence is accounted for by a modification of the drag coefficient.Results show that inclusion removal is difficult with a single melt since the growth of a β-phase layer leads to an initial increase in the defect size. The inclusion behaviour is highly dependent on the pool hydrodynamics and on inclusion characteristics.In order to clarify dissolution aspects of these defects and to measure their dissolution kinetics, synthetically processed defects were introduced into molten titanium heated in an electron beam melting furnace. Dissolution rates were calculated by measuring the size of the defects before and after the experiments and the results were used to validate the numerical models. Furthermore, the experiments show that dissolution kinetics highly depend on fluid motion and temperature
Perrudin, François. "Étude de la dissolution de diverses terres rares dans des liquides silicatés (CMAS) de composition variable : contribution au développement des barrières thermiques en ZRO₂-RE₂O₃ (RE=La-Lu)." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0277/document.
Повний текст джерелаFine particles of sand, dust or volcanic ashes ingested by aircraft engines are well-known to damage Thermal Barrier Coatings (TBC) when they infiltrate their porous microstructure as molten silicate (CMAS). They are mainly constituted of CaO-MgO-Al2O3-SiO2 in variable proportions and also contain metallic oxides. RE2Zr2O7 compositions are TBC candidate materials as they have shown efficiency to mitigate CMAS infiltration due to their reactivity with synthetic CMAS. Indeed, the dissolution reaction leads to rapid sealing of the topcoat porosity mainly due to the formation of crystalline Ca2Gd8(SiO4)6O2 apatite. However, many rare-earth silicates are likely to compete with apatite crystallization and little is known on reaction kinetics and thermodynamics involving RE2O3 and multi-component CMAS system. This work aims to determine the influence of CMAS and rare earth composition on dissolution and precipitation mechanisms. A simplified CAS was first selected with eutectic (1170°C), 65SiO2-26CaO-9Al2O3 (mol. %) composition. Dissolution of various RE2O3 with increasing basicity (RE = Yb, Dy, Gd, Sm and Nd) as well as synthetic apatite and cyclosilicate Ca3RE2(Si3O9)2 phases was then performed at 1200°C in CAS-melt. Finally, fixed MgO and Fe2O3 contents were added to CAS melt with an increasing CaO/SiO2 ratio. The results showed that RE2O3 dissolution mechanism is indirect. Apatite formation results from local equilibrium at the interface with solid RE2O3 whatever the rare earth and CMAS composition. Its crystallization is favored when Ca2+ and RE3+ ionic radii are close as they are both distributed within 9-fold coordination sites. Conversely, Ca and RE mismatch leads to rapid nucleation of cyclosilicate phase in CAS as they are preferentially distributed within a 6-fold coordination site. MgO and Fe2O3 addition in CAS as well as RE2O3 basicity tend to increase RE solubility in silicate melt. Phases in thermodynamic equilibrium strongly depend on CMAS composition but generally exhibits lower RE solubility and dissolution rate in melt than apatite
Rassineux, François. "Altération des mortiers : étude expérimentale et analogues anciens." Poitiers, 1987. http://www.theses.fr/1987POIT2314.
Повний текст джерелаBiganska, Olga. "Étude physico-chimique des solutions de cellulose dans la N-Méthylmorpholine-N-Oxyde." Phd thesis, École Nationale Supérieure des Mines de Paris, 2002. http://tel.archives-ouvertes.fr/tel-00443727.
Повний текст джерелаAssa, Kaudjhis Narcisse Bonaventure. "Étude pratique d'analyse régionale en Côte d'Ivoire : l'aménagement de la Vallée du Bandama : bilan, une décennie aprés la dissolution de l'A.V.B." Paris 4, 1996. http://www.theses.fr/1996PA040402.
Повний текст джерелаDebure, Mathieu. "Étude de la dissolution de verres borosilicatés en présence de minéraux magnésiens modèles représentatifs des minéraux de l'argilite du Callovo-Oxfordien." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00797458.
Повний текст джерелаDebure, Mathieu. "Étude de la dissolution de verres borosilicatés en présence de minéraux magnésiens modèles représentatifs des minéraux de l'argilite du Callovo-Oxfordien." Electronic Thesis or Diss., Paris, ENMP, 2012. http://www.theses.fr/2012ENMP0047.
Повний текст джерелаBorosilicate glasses dissolution has been studied in presence of magnesium minerals. Those minerals (dolomite, illite, smectite…) belong to the Callovo-Oxfordian (COx) claystone layer, studied in France as a potential site for nuclear waste disposal. Such minerals contain magnesium, an element able to sustain glass alteration when it is available in solution. In the confined media of the wastes disposal, thesolids reactivity controls the solution composition and can be the driving force of nuclear glass alteration. Experiments show that magnesium carbonates (hydromagnesite and dolomite) increase in the glass alteration: the precipitation of magnesium silicates consumes silicon which slows down the formation of the glass passivating layer. The lower the magnesium mineral solubility, the lower the glass alteration.The purified clay phases (illite, smectite…) from the COx layer increase the glass alteration. Half the magnesium was remplaced by sodium during the purification process. In such conditions, the effect of clay phases on glass alteration is in part due to the acidic pH-buffering effect of the clay fraction. The GRAAL model implemented in the geochemical transport code HYTEC has confirmed and quantified the mechanisms put in evidence in the experiments. Cells diffusion experiments where the two solids were separated by an inert diffusion barrier allow to valid reactive transport modelling. Such experiments are more representative of the glass package which will be separated from the COx by corrosion products. They show that glass alteration rate is reduced when solids are not close
Flaathen, Therese Kaarbø. "Étude de l'interaction eau-basalte lors de l'injection de CO2." Phd thesis, Université Paul Sabatier - Toulouse III, 2009. http://tel.archives-ouvertes.fr/tel-00421959.
Повний текст джерелаUne étude détaillée de la composition chimique des eaux souterraines au pied du volcan Mont Hekla, dans le sud de l'Islande, a d'abord été menée afin d'évaluer l'évolution chimique des fluides et la mobilité des métaux toxiques lors des interactions entre basalte et fluides riches en CO2. Ces fluides fournissent un analogue naturel pour estimer les conséquences de la séquestration du CO2 dans les basaltes. La teneur de ces fluides en carbone inorganique dissous diminue de 3,88 à 0,746 mmole/kg avec l'augmentation de la mise en solution du basalte tandis que le pH passe de 6,9 à 9,2. Ces observations fournissent une preuve directe du potentiel qu'offre la dissolution du basalte pour séquestrer le CO2. Les concentrations des métaux toxiques dans ces eaux sont faibles et la modélisation des chemins réactionnels suggère que la calcite et les (oxy)hydroxydes de fer piègent ces métaux, suite à l'alcalinisation des fluides induite par la dissolution continue du basalte.
On sait que ce sont les cations divalents libérés par la dissolution du verre basaltique qui contrôlent la minéralisation du gaz carbonique dans les basaltes. La vitesse de dissolution du verre basaltique peut être accrue par l'addition de ligands qui se complexent avec Al3+. L'ion SO42- fait partie de ces ligands et l'étude de son impact sur la vitesse de dissolution du verre basaltique a été conduite dans des réacteurs de type ‘mixed flow' à 50°C et 3 < pH < 10. Le soufre est souvent présent dans les gaz émis par les centrales électriques et son stockage constitue un challenge environnemental. La co-injection avec CO2, si elle est réalisable, peut donc constituer une nouvelle méthode peu couteuse de stockage du soufre généré par l'industrie. En accord avec les modèles actuels décrivant la cinétique de dissolution du verre basaltique en fonction de la composition de la solution aqueuse, les résultats de ce travail montrent que SO42-augmente la vitesse de dissolution du verre aux conditions acide mais qu'il n'a aucun effet aux pH alcalins. Ces résultats suggèrent à la fois que 1) la co-injection de sulfate peut accélérer la minéralisation du CO2 dans les basaltes et 2) les modèles cinétiques existant permettent une description précise de la dissolution du verre basaltique.
Afin d'évaluer plus précisément l'impact des ions sulfates sur la vitesse de précipitation des carbonates, la vitesse de précipitation de la calcite en régime stationnaire a été mesurée dans des réacteurs à circulation ‘mixed flow' à 25°C et pH ~9.1. Les résultats montrent qu'en présence de 0.005 M de Na2SO4 la vitesse de précipitation de la calcite est diminuée d'environ 40% et qu'ainsi la co-injection de sulfate peut ralentir la précipitation de la calcite aux pH typiques de la précipitation de ce minéral en subsurface. Des expériences supplémentaires sont prévues pour caractériser définitivement l'effet du sulfate aux conditions attendues aux sites d'injection du CO2 en subsurface.
Casetta, Mathilde. "Procédé de teinture du polyester par les colorants dispersés : étude physico-chimique et modélisation+." Lille 1, 2000. http://www.theses.fr/2000LIL10181.
Повний текст джерелаAinsi, l'étude de l'influence de différents paramètres (temps, température, produits auxiliaires,. . . ) sur le comportement des colorants en solution aqueuse met en évidence des phénomènes de déstabilisation des dispersions et permet de sélectionner un colorant présentant des propriétés adaptées à la teinture à haute température. La réalisation des expériences de teinture pour diverses températures de mise en oeuvre et avec différentes concentrations initiales en colorant conduit à l'obtention des isothermes de partage qui reflètent la manière dont le colorant se répartit entre le bain et la fibre. La procédure de modélisation est réalisée à partir des valeurs obtenues suite à ces expériences et aboutit à l'établissement de modèles mathématiques du coefficient de diffusion. Les paramètres intervenant dans ces nouveaux modèles sont identifiés grâce à l'utilisation de l'optimisation par les algorithmes génétiques et leur dépendance par rapport. à la. Concentration initiale en colorant et la température est établie
Poulard, Karine. "Étude de l'influence de la corrosion en milieu basique sur le relâchement d'activité par la zircone : application au stockage des coques." Lyon 1, 2001. https://tel.archives-ouvertes.fr/tel-00007333.
Повний текст джерелаFlaathen, Therese Kaarbo. "Étude de l'interaction eau-basaltes lors d'injection de CO2." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/677/.
Повний текст джерелаThe potential dangers with increased concentration of CO2 in the atmosphere, such as climate changes and sea level rise, have lead to an interest in CO2 sequestration in geological formations. The thermodynamically most stable way to store carbon is as carbonate minerals. Carbonate mineral formation, however, requires divalent cations originating from a non-carbonate source. One such source is basaltic rocks which contain high concentrations of Ca2+, Mg2+ and Fe2+. The potential for forming carbonate minerals through the injection of CO2 into basalt is under investigation in Iceland and several other places around the world. The aim of this thesis is to help optimize carbonate mineral precipitation in basalts during CO2 injection through a series of related field and laboratory studies. A detailed study of the chemical composition of the groundwater surrounding the Mt. Hekla volcano in south Iceland was performed to assess fluid evolution and toxic metal mobility during CO2-rich fluid basalt interaction. These fluids provide a natural analogue for evaluating the consequences of CO2 sequestration in basalt. The concentration of dissolved inorganic carbon in these groundwaters decreases from 3. 88 to 0. 746 mmol/kg with increasing basalt dissolution while the pH increases from 6. 9 to 9. 2. This observation provides direct evidence of the potential for basalt dissolution to sequester CO2. The concentrations of toxic metals in these waters are low and reaction path modeling suggests that calcite and Fe(III) (oxy)hydroxides scavenge these metals as the fluid phase is neutralized by further basalt dissolution. The rate limiting step for mineralization of CO2 in basalt is thought to be the release of divalent cations to solution through basaltic glass dissolution. .
N'Takpé, Adjoua Marie-Hortense. "La société anonyme unipersonnelle en droit OHADA : étude critique." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0097.
Повний текст джерелаThe one-person limited company under the OHADA LAW has seen itslegal regime being defined with reference to the regime of the multi-persons limited company,with minimum adaptations. In fact the one-person character of the Limited company gives it a certain peculiarity that renders inappropriate the pure and simple transportation of rules of the multi-person limited company model. Besides the difficulty of implementation that it oftenentails, the technique of referring leaves unresolved many questions raised by the one-personlimited company model. The legal regime of the one-person limited company as a whole thatarises is insufficiently adapted to the unique shareholder.An adaptation of the one-person limited company legal regime of the OHADA LAWto the particularity of the one-person thus becomes necessary. It has to be undertaken underthe simplification of rules, on the one hand with regards to the company, through rules relatedto its constitution and its evolution, on the other hand, with respect to the actors that are thesole shareholders, administrative and control bodies
Jakab, Sandrine. "Cinétique de précipitation par voie électrochimique et de dissolution de solides mixtes de type molybdates ou hydroxydes/oxydes de lanthanide : étude de gravimétrie." Paris 6, 2009. http://www.theses.fr/2009PA066774.
Повний текст джерелаDubois, Jean Luc. "Contribution à la connaissance des intéractions principes actifs-polymères : étude de dispersions solides de polyéthylénéglycol." Paris 5, 1992. http://www.theses.fr/1992PA05P636.
Повний текст джерелаLavergne-Gosselin, Laurence. "Étude de détecteurs nucléaires minces, passivés et implantés, réalisés à partir de silicium épitaxique : applications aux ions lourds et au rayonnement synchrotron." Paris 11, 1989. http://www.theses.fr/1989PA112094.
Повний текст джерелаPerrudin, François. "Étude de la dissolution de diverses terres rares dans des liquides silicatés (CMAS) de composition variable : contribution au développement des barrières thermiques en ZRO₂-RE₂O₃ (RE=La-Lu)." Electronic Thesis or Diss., Université de Lorraine, 2018. http://www.theses.fr/2018LORR0277.
Повний текст джерелаFine particles of sand, dust or volcanic ashes ingested by aircraft engines are well-known to damage Thermal Barrier Coatings (TBC) when they infiltrate their porous microstructure as molten silicate (CMAS). They are mainly constituted of CaO-MgO-Al2O3-SiO2 in variable proportions and also contain metallic oxides. RE2Zr2O7 compositions are TBC candidate materials as they have shown efficiency to mitigate CMAS infiltration due to their reactivity with synthetic CMAS. Indeed, the dissolution reaction leads to rapid sealing of the topcoat porosity mainly due to the formation of crystalline Ca2Gd8(SiO4)6O2 apatite. However, many rare-earth silicates are likely to compete with apatite crystallization and little is known on reaction kinetics and thermodynamics involving RE2O3 and multi-component CMAS system. This work aims to determine the influence of CMAS and rare earth composition on dissolution and precipitation mechanisms. A simplified CAS was first selected with eutectic (1170°C), 65SiO2-26CaO-9Al2O3 (mol. %) composition. Dissolution of various RE2O3 with increasing basicity (RE = Yb, Dy, Gd, Sm and Nd) as well as synthetic apatite and cyclosilicate Ca3RE2(Si3O9)2 phases was then performed at 1200°C in CAS-melt. Finally, fixed MgO and Fe2O3 contents were added to CAS melt with an increasing CaO/SiO2 ratio. The results showed that RE2O3 dissolution mechanism is indirect. Apatite formation results from local equilibrium at the interface with solid RE2O3 whatever the rare earth and CMAS composition. Its crystallization is favored when Ca2+ and RE3+ ionic radii are close as they are both distributed within 9-fold coordination sites. Conversely, Ca and RE mismatch leads to rapid nucleation of cyclosilicate phase in CAS as they are preferentially distributed within a 6-fold coordination site. MgO and Fe2O3 addition in CAS as well as RE2O3 basicity tend to increase RE solubility in silicate melt. Phases in thermodynamic equilibrium strongly depend on CMAS composition but generally exhibits lower RE solubility and dissolution rate in melt than apatite
Hubert, Nathalie. "Contribution à la détermination des propriétés thermodynamiques des solutions aqueuses d'électrolytes forts : étude des systèmes H2O-NaCl et H2O-Na2SO4 entre 25°C et 100°C par mesures d'équilibre liquide-vapeur et par calorimétrie." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL005N.
Повний текст джерелаCoppee, Thibault. "Étude expérimentale et numérique de la durabilité du gypse dans les structures géotechniques : approche couplée hydro-mécanique et chimique." Electronic Thesis or Diss., Université Gustave Eiffel, 2023. http://www.theses.fr/2023UEFL2061.
Повний текст джерелаThe extension of anthropogenic activities leads to the development of infrastructure in areas rich in gypsum and subject to the hazards of land movements and cavities. Indeed, gypsum, a rock from the evaporite family, is commonly encountered and exploited by excavation or tunneling. This exploitation can generate over time phenomena of rising fontis. In addition, gypsum formations can also play a “soap board” role in triggering landslides and causing pathologies on geotechnical structures. If gypsum is particularly studied by geochemists through dissolution kinetics tests given the high solubility of this material (2.5 g/L at 20°C) and its variability depending on physicochemical conditions, the permeability properties of gypsum remain less well known. Although this low permeability rock has a porous structure allowing fluid circulation, it is often considered impermeable and subject to simple dissolution by regression of its contact surface, without formation of an alteration gradient. This thesis work aims to study the flow of a fluid (water) in a gypsum material or on its surface while the material dissolves. This study includes both an experimental approach via measuring the evolution of hydromechanical properties and a numerical approach via coupled thermo-hydro-mechanical and chemical modeling (THMC). Firstly, six gypsum facies, more or less heterogeneous in their mineralogical composition, were collected and characterized in terms of porosity and mechanical properties. This part made it possible to highlight the variability of properties depending on a given facies. For example, the porosity of around 1% for the albastroid form can vary up to 10% for the saccharoid facies.3 facies were then retained to undergo alteration by percolation over maximum periods of 2 months. The evolution of their morphology was analyzed and quantified using porosimetric and non-destructive measurement methods (speed of sound, resonance frequency) depending on the facies and their microstructural properties. Percolation tests show in particular the non-systematic establishment of preferential dissolution paths in saccharoid gypsums. This evolution is associated with several parameters including the diameter of access to the pore. In the case of facies with a significant fraction of secondary mineral phases such as clays or carbonates (calcite), we observe the same preferential path process earlier. An erosion test on gypsum board was also developed to monitor the degradation of the material and to look for clues as to the initiation of this phenomenon. In parallel, dissolution tests on powder were carried out to measure the dissolution kinetics parameters for each facies, by varying the stirring speeds of the suspensions, the temperature and the particle size of the powders tested. Measurements of gypsum sensitivity to flow and degradation show that saccharoid gypsum is more sensitive than matrix gypsum. All the chemical parameters (dissolution rate particularly at very low flow speed) and mechanical parameters (porosity, pore diameter, elastic modulus, etc.) obtained experimentally respectively on the powders and the percolated specimens fed into a model of evolution of the mechanical and hydraulic properties of gypsum materials in the presence of a dissolution process (coupling of effects). The model was implemented in the Disroc finite element calculation code to simulate the evolution of the mechanical stability of a geotechnical structure subjected to an undersaturated fluid flow, infiltrating into a gypsum pocket
Miroud, Lakhdar. "Étude par traction lente de la corrosion sous contrainte des aciers au carbone en milieu alcalin : rôle des inhibiteurs passivants." Compiègne, 1991. http://www.theses.fr/1991COMPD371.
Повний текст джерелаJutard, Jérôme. "Instabilités interfaciales morphologiques : étude de l'évolution morphologique d'une électrode de cuivre soumise à une réaction électrochimique." Phd thesis, Grenoble INPG, 1993. https://theses.hal.science/tel-00844069.
Повний текст джерелаStolarz, Jacques. "Corrosion d'aciers inoxydables austénitiques au silicium dans les conditions tranpassives." Paris, ENMP, 1989. http://www.theses.fr/1989ENMP0133.
Повний текст джерела