Дисертації з теми "Dissolution (Chimie)"
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Driouche, Mohammed. "Caractérisation des alumino-silicates par dissolution dans l'acide fluorhydrique dilué." Lyon, INSA, 1987. http://www.theses.fr/1987ISAL0020.
Повний текст джерелаPatel, Saket. "Development of polarizing agents for dissolution-dynamic nuclear polarization technique." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0729/document.
Повний текст джерелаNMR and MRI play a key role in science and notably in chemistry and clinical research. Both NMR and MRI techniques suffer from sensitivity limitation and hyperpolarization can help push back this limitation by increasing the signal by 1-4 orders of magnitudes. Dynamic nuclear polarization (DNP) is one of the most widely used method to overcome the sensitivity limitation of NMR/MRI. This thesis concerns the design and synthesis of new improved UV-induced non-persistent polarizing agents for dissolution DNP and matrix dependence of the magnetic properties of free radical at high magnetic field and low temperature. The DNP efficiency of UV-induced polarizing agents has been tested at 6.7 T and 1 K. Herein, we overcome the issue of providing UV-radical precursors that are not involved in any metabolic pathway, improvement in generated radical yield, and 13C dDNP performances. The DNP efficiency of these radicals was tested for the [U-2H, U-13C]-D-glucose and 13C-dihydroxyacetone (DHAc). In the optimal conditions, for glucose polarization, a usable liquid-state polarization of 32% has been achieved, the highest value reported in the literature to date. Additionally, photo-irradiation of phenylglyoxylic acid (PhGA) using visible (Vis) light instead of UV-light produced a non-persistent radical that can be used to hyperpolarize UV-sensitive probes. Furthermore, matrix dependence and effect of [Gd] 3+ complex on trityl radical (AH111501) relaxation time (T1e), high field EPR study, and dDNP experiment on [U-2H, U-13C]-D-glucose has been studied at 6.7 T
Patel, Saket. "Development of polarizing agents for dissolution-dynamic nuclear polarization technique." Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0729.
Повний текст джерелаNMR and MRI play a key role in science and notably in chemistry and clinical research. Both NMR and MRI techniques suffer from sensitivity limitation and hyperpolarization can help push back this limitation by increasing the signal by 1-4 orders of magnitudes. Dynamic nuclear polarization (DNP) is one of the most widely used method to overcome the sensitivity limitation of NMR/MRI. This thesis concerns the design and synthesis of new improved UV-induced non-persistent polarizing agents for dissolution DNP and matrix dependence of the magnetic properties of free radical at high magnetic field and low temperature. The DNP efficiency of UV-induced polarizing agents has been tested at 6.7 T and 1 K. Herein, we overcome the issue of providing UV-radical precursors that are not involved in any metabolic pathway, improvement in generated radical yield, and 13C dDNP performances. The DNP efficiency of these radicals was tested for the [U-2H, U-13C]-D-glucose and 13C-dihydroxyacetone (DHAc). In the optimal conditions, for glucose polarization, a usable liquid-state polarization of 32% has been achieved, the highest value reported in the literature to date. Additionally, photo-irradiation of phenylglyoxylic acid (PhGA) using visible (Vis) light instead of UV-light produced a non-persistent radical that can be used to hyperpolarize UV-sensitive probes. Furthermore, matrix dependence and effect of [Gd] 3+ complex on trityl radical (AH111501) relaxation time (T1e), high field EPR study, and dDNP experiment on [U-2H, U-13C]-D-glucose has been studied at 6.7 T
Ziouane, Yannis. "Dissolution de poudres d'oxydes mixtes (U,Pu)O2 monophasées." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS005.
Повний текст джерелаThe main objective of this study is to acquire data on the dissolution of (U, Pu)O2 compounds to support the understanding of the phenomena occurring during the dissolution steps of MOX fuels irradiated in light water or sodium fast reactors. Previous studies, in particular on unirradiated MOX fuel, have highlighted the complexity of understanding the dissolution mechanisms through a direct approach. Indeed, the dissolution depends on a large number of parameters, which are mainly chemical dissolution parameters (acidity, temperature…). But it also depends on the physico-chemical characteristics of the fuel pellets (plutonium content, homogeneity of the plutonium content, microstructure, geometry...), a majority of which being highly dependent on the manufacturing process used. To avoid getting averaged responses due to the presence of heterogeneity in the Pu distribution in pellets, it is proposed to carry out a study on single-phase compounds in the shape of powders characterized by a well-defined stoichiometry (U and Pu) and a perfectly determined morphology. A step approach allowed the determination of the key parameters controlling the dissolution kinetics of these actinide oxides (specific surface area, crystal size, Pu content, activity of nitrate ions, dissolution temperature).A global kinetics law describing the dissolution kinetics of U1-xPuxO2 oxides was established from 45 dissolution tests (with 0≤x≤1, [HNO3] and temperature ranging from 1.5 to 8.5M and from 50 to 95°C respectively). Despite the 5 orders of magnitude between dissolution kinetics of UO2 and PuO2, the model shows a good precision. Additional dissolution tests were conducted on different single-phase oxide powders to validate the predictive quality of this model
Badie, Jérôme. "Réduction de l'iodure d'argent en solution aqueuse : application à la séparation poussée de l'iode lors du traitement des combustibles nucléaires usés." Aix-Marseille 3, 2002. http://www.theses.fr/2002AIX30005.
Повний текст джерелаSilver iodide is a key-compound in nuclear chemistry either in accidental conditions or during the reprocessing of spent nuclear fuel. In french reprocessing plants, iodine is trapped in the dissolver off-gas treatment unit by scrubbing with a caustic soda solution and by chemisorption on mineral porous traps impregnated with silver nitrate, leading to the production of silver iodide and silver iodate. Enhanced separation policy would make necessary to recover iodine from the filters by silver iodide dissolution during a reducing treatment. For this purpose, ascorbic acid and hydroxylamine were used
Loodts, Vanessa. "Influence of chemical reactions on convective dissolution: a theoretical study." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/242093.
Повний текст джерелаDoctorat en Sciences
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Lemaigre, Lorena. "Convective patterns triggered by chemical reactions, dissolution and cross-diffusion: an experimental study." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/229759.
Повний текст джерелаThe understanding of the effect of chemical reactions on fluid motions is an issue at the heart of numerous applications, such as polluted soil remediation or geological storage of CO2. In this context, the goal of our work is to understand through an experimental approach to what extent a chemical reaction is able to modify the development and the properties of buoyancy-driven convective patterns. Our experiments are carried out by putting in contact reactive aqueous solutions or non reactive liquids in a vertical Hele-Shaw cell. This model reactor consists in two glass plates separated by a thin gap and is commonly used to study fluid motions at the laboratory scale. We analyze in various cases the spatio-temporal structures resulting from the build-up of unstable density gradients due to chemical reactions, dissolution processes or cross-diffusion. During our thesis, we first studied the interplay between an acid-base reaction and buoyancy-driven instabilities, namely double diffusion and the Rayleigh-Taylor instability. We have shown that this simple A+B -->C type of reaction breaks the up-down symmetry which is characteristic of the non reactive patterns. Next we focused on a chemical reaction featuring more complex kinetics, namely the oscillating Belousov-Zhabotinsky reaction. The reactants were initially segregated in space in order to spatially localize the reaction at the interface between two solutions with different composition. Our aim is to obtain a localized chemical oscillator and to study its effect on buoyancy-driven flows. To do so, we first characterized the corresponding reaction-diffusion patterns which develop from this particular initial condition. We showed that, in the absence of convection, the spatial segregation of the reactants produces spatial gradients in the excitability and hence the nucleation of one or two spatially localized wave trains. We observed that in the presence of convective motions, these wave trains can also appear and remain localized, according to the type of buoyancy-driven instability which is at play. Moreover the chemical reaction triggers the onset of additional patterns. We have also characterized the hydrodynamic patterns which appear due to cross-diffusion in microemulsions. We have shown that, if a concentration gradient of one species is able to trigger a flux of another species, an unstable density stratification may appear and cause the onset of convection. Finally we have studied the convective dissolution of an organic phase (alkyl formate) into an aqueous phase. We have shown that, above a certain threshold, an increase in the miscibility between the two phases leads to an increase in the intensity of the fluid motions. Our results help to understand the effect of bimolecular or oscillating reactions, dissolution processes and cross-diffusion on the properties of reaction-diffusion-convection structures. This work paves the way towards the study of novel self-organized spatio-temporal patterns coupling the organizing power of chemical reactions and of hydrodynamic flows, both in aqueous solutions and multiphase media.
Doctorat en Sciences
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Bouché, Karine. "Etude thermocinétique de la dissolution de métaux solides (fer et nickel) dans l'aluminium liquide." Aix-Marseille 1, 1995. http://www.theses.fr/1995AIX11051.
Повний текст джерелаDeleuze, Marc. "Dissolution contrôlée du quartz en milieu basique. Application à la mise en fréquence de résonateurs piézoélectriques." Montpellier 2, 1994. http://www.theses.fr/1994MON20107.
Повний текст джерелаMuzeau, Benoist. "Mécanismes d’altération sous eau du combustible irradié de type UOX." Paris 11, 2007. http://www.theses.fr/2007PA112101.
Повний текст джерелаThe mechanisms of underwater alteration of spent fuels need to be understood on the assumption of a direct disposal of the assemblies in a geological formation or for long duration storage in pool. This work is a contribution to the study of the effects of the alpha and/or beta/gamma radiolysis of water on the oxidation and the dissolution of the UO2 matrix of UOX spent fuel. The effects of the alpha radiolysis, predominant in geological disposal conditions, were quantified using samples of UO2 doped with plutonium. The leaching experiments highlighted two types of control for the matrix alteration according to the alpha activity. The first is based on the radiolytic oxidation of the surface and leads to a continuous release of uranium in solution whereas the second is based on a control by the solubility of uranium. An activity threshold, located between 18 MBq/g and 33 MBq/g, was defined in a carbonated water. The value of this threshold is dependent on the experimental conditions and the presence or not of electro-active species such as hydrogen in the system. The effects of the alpha/beta/gamma radiolysis in relation with the storage conditions were also quantified. The experimental data obtained on spent fuel indicate that the alteration rate of the matrix based on the behaviour of tracer elements (caesium and strontium) reached a maximum value of some mg/m. J, even under very oxidizing conditions. The solubility of uranium and the nature of the secondary phases depend however on the extent of the oxidizing conditions
Devigne, Vincent Graillot Didier Mikelic Andro Batton-Hubert Mireille. "Écoulements et conditions aux limites particulières appliquées en hydrogéologie et théorie mathématique des processus de dissolution / précipitation en milieux poreux = Flows and Particular Boundary Conditions applied in Hydrogeology and Mathematical Theory of Dissolution/Precipitation process in porous media." Lyon : [s.n], 2006. http://tel.archives-ouvertes.fr/docs/00/13/20/36/PDF/UCBL_manuscrit.pdf.
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 джерелаAupoil, Julien. "Etude des mécanismes de dissolution/polycondensation lors de la géopolymérisation : réactivité du métakaolin et influence de la solution d'activation." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLET014.
Повний текст джерелаGeopolymers are alternative aluminosilicates binders prepared from metakaolin and alkaline silicate solutions. However, the origin of their setting through a massive polycondensation of aluminosilicates remains unclear. The influence of hydroxide ions and of the stoichiometry Si-Al-alkali in solution has to be clarified. But these species are also implicated in the dissolution of metakaolin. First, interactions between hydroxides and silicates in the activating solution were expressed by means of the Hammett function H- to quantify free hydroxides, and of the buffering capacity β to quantify hydroxide bonded to silicates. Then the dissolution was dissociated from the polycondensation by progressively diluting the metakaolin mixed with the solution. The dissolution was then monitored by microcalorimetry and static 27Al NMR. As a complement, the geopolymerization was described as occurring in several steps using rheometry, conductimetry, SAXS and QENS. Third, a microcalorimetry-NMR correlation exhibited that the dissolution pathway remained unchanged whatever the initial silicate and sodium concentrations and the nature of the alkali used, thus whatever the initial H- and β. On the contrary, the higher those parameters, the higher the dissolution rate. The rheological setting time of geopolymers is also directly dependent on the dissolution rate. The suggested mechanisms involves that the initially bonded hydroxides in the activating solution, expressed by β, are progressively released in solution according to a dissolution-condensation loop process
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 джерелаFournier, Sabine. "Etude de la dissolution des oxydes mixtes (U,Pu)O2 à forte teneur en plutonium." Montpellier 2, 2000. http://www.theses.fr/2000MON20203.
Повний текст джерелаBouali, Noureddine. "Dissolution des gaz dans des solutions aqueuses d'agents tensioactifs ioniques : aspects cinétique et thermodynamique." Montpellier 2, 1996. http://www.theses.fr/1996MON20264.
Повний текст джерелаJakab, 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 джерелаBillard, Olivier. "Mécanismes du décapage des peintures par voie chimique : de la compréhension des phénomènes physico-chimiques au développement d'outils d'aide à la formulation de décapants." Lille 1, 1998. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1998/50376-1998-458.pdf.
Повний текст джерелаDans notre quatrième partie, nous avons étudié les mécanismes de séparation peinture / subjectile à travers des tests originaux de pelage par voie humide. Ces résultats ont été interprétés grâce à la théorie thermodynamique sur l'adhésion. Le pouvoir pelant des solvants a été relié à leur polarité ou à leur caractère acido-basique. Enfin, notre cinquième partie a été consacrée au développement d'outils pour la formulation de décapants : nous avons appliqué le principe de la vectorisation à la recherche de solvants susceptibles d'accélérer la diffusion du DMSCO, nous avons élaboré un modèle semi-empirique permettant de calculer le temps de décapage d'un solvant quelconque vis-à-vis d'une peinture en batiment et, enfin, nous avons mis au point une méthode d'identification systématique des solvants verts : le "solvent design"
Maisse, Éric. "Analyse et simulations numériques de phénomènes de diffusion-dissolution - précipitation en milieux poreux, appliquées au stockage de déchets." Lyon 1, 1998. http://www.theses.fr/1998LYO10021.
Повний текст джерелаArcis, Hugues. "Etude thermodynamique de la dissolution du dioxyde de carbone dans des solutions aqueuses d'alcanolamines." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2008. http://tel.archives-ouvertes.fr/tel-00731443.
Повний текст джерелаThirioux, Laurence. "Mécanismes et cinétique de dissolution de matériaux phosphatés cristallisés et amorphes en milieux acides chlorhydrique et citrique." Phd thesis, Université d'Orléans, 1990. http://tel.archives-ouvertes.fr/tel-00802315.
Повний текст джерелаTrinh, Pierre. "Réactions d'oxydation dans une mousse : application à la dissolution du cuivre." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS116.
Повний текст джерелаRetrieving metals contained in waste from electric and electronic equipements (WEEEs) is an environnemental and economic challenge. One step of this process is hydrometallurgy : metals contained in crushed WEEEs are lixiviated by concentrated inorganic acid solutions. In this framework, we explore the use of liquid foams for copper lixiviation. Liquid foams have two main advantages : decreasing the liquid waste volume and benefiting from oxidizing properties of the bubble gas. Two reactants that require dioxygene to dissolve copper have been studied : hydrochloric acid and hydroxylamine. Compared to a solution, liquid foams increase the kinetics of copper dissolution reactions that imply a gas phase. This effet is due to a faster dioxygen transport to the metal. To go further into the understanding of these transport phenomena, we designed a forced drainage experimental setup. It consists in injecting the foaming solution at a constant flowrate on the top of a foam column. We then observe two regimes. In the first one, the dissolved copper quantity is limited by the protons flux that reaches the copper surface. Thus, this quantity increases with the set flowrate. In the second regime, it is limited by the dioxygene flux and so it decreases with the flowrate. Thus, the foam structure directly influence the copper dissolved quantity
Beaudoux, Xavier. "Dissolution réductrice d'oxydes de lanthanides et de PuO2 assistée par ultrasons." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS046.
Повний текст джерелаIn the French nuclear program, the reactor fuel consists of uranium oxides or uranium plutonium mixed oxides (called MOX). Developments are constantly made on the resulting reprocessing of these fuels in order to optimize the recovery of reusable materials and to minimize the waste volume. In the case of MOX dissolution, the amount of Pu-rich dissolution residues is sometimes high despite the use of hard chemical conditions (oxidizing and corrosive). The difficulty to dissolve PuO2 batches declared non-standard during the fabrication of MOX can also be a technological barrier. In this context, sonochemistry can be considered as an alternative to current methods of dissolution of PuO2 or Pu enriched MOX. First, experiments of sonochemical dissolution were performed on an inactive analogue of PuO2, namely CeO2. The results were then used as a working basis for the dissolution of PuO2. Under reducing and acidic conditions, much milder than those used industrially, the complete dissolution of these two oxides was carried out within a few hours. Meanwhile, a related study showed that it is possible to completely dissolve lanthanide mixed oxides by a process of sonocatalytic and reductive dissolution in the presence of Pt. The dissolution rates increase with the trivalent lanthanide content within the oxide. Finally, the last part was devoted to the dissolution under magnetic stirring of Ce-based oxides in the presence or absence of noble metals, in weakly acidic media containing reducing natural molecules. Under these conditions, a complete, rapid and selective dissolution of these oxides was observed. These last two studies present an interest beyond the scope of nuclear chemistry, concerning the recycling of industrial materials (catalytic converters, fuel cells...)
Chbihi, Mohammed El Mahi. "Caractérisation de l’état de désorganisation des argiles thermiquement activées." Lyon, INSA, 1986. http://www.theses.fr/1986ISAL0041.
Повний текст джерелаLe, Guen Yvi. "Etude expérimentale du couplage chimie-mécanique lors de la percolation d'un fluide réactif dans des roches sous contrainte, dans le contexte de la séquestration géologique du CO2." Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00120023.
Повний текст джерелаLes cellules triaxiales utilisées pour les expériences permettent de contrôler et de mesurer indépendamment les contraintes, la température, la composition et la pression du fluide injecté. Les déformations verticales ont été mesurées sur plusieurs mois, avec une résolution sur le taux de déformation de 10-12 s-1. En parallèle, les fluides étaient analysés afin de quantifier les interactions fluide-roche.
Pour les calcaires, l'écoulement de fluides avec CO2 accélère la déformation de 1,7 à 5 fois ; par contre, la déformation du grès ne s'est pas accrue. L'accélération de la déformation des calcaires est expliquée par l'acidification du fluide injecté qui augmente la solubilité et les cinétiques de réaction. Inversement, la faible déformation du grès est expliquée par la faible influence du CO2 sur le quartz. Des observations par rayons X ont montré l'importance de la composition et de la structure de la roche sur l'évolution de la porosité. Des simulations mécaniques élastiques montrent que l'hétérogénéité de la dissolution peut induire des concentrations de contrainte dans la roche.
L'évolution des propriétés rhéologiques de certaines roches réservoir est expliquée par des mécanismes de déformation par dissolution sous contrainte, prenant place, en parallèle, dans les pores de la roche, et au niveau des contacts entre les grains.
Jhajharia, Aditya. "Dissolution dynamic nuclear polarization of deuterated molecules." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEE046/document.
Повний текст джерелаNowadays, Nuclear Magnetic Resonance (NMR) has become an inevitable spectroscopic technique that can be applied in many fields of science and medicine. However it is limited by low sensitivity due to the low nuclear polarization, defined by the difference of populations between the energy levels involved, thus leading to long experimental times. This drawback can be overcome by using the huge polarization of unpaired electrons compared to nuclear spins and its transfer to nuclear spins at low temperatures (using microwave irradiation) to achieve a large nuclear magnetization - a method know as dynamic nuclear polarization (DNP). Sami Jannin and co-workers have recently combined the cross-polarization (CP) method with DNP at very low temperatures to polarize low γ nuclei faster by transferring the electron polarization to protons and then to low γ nuclei like ¹³C. This thesis demonstrates that the efficiency of the CP method can be improved by switching the microwave irradiation off for a few hundred milliseconds prior to CP. By performing these microwave gating experiments, ¹³C polarizations for sodium [1-¹³C]acetate as high as 64% could be achieved with a polarization build-up time constant as short as 160 s. The hyperpolarized sample can subsequently be rapidly dissolved to achieve NMR signal enhancement in the liquid state at ambient temperature. This method has been developed by Ardenkjaer-Larsen and co-workers in 2003 and became known as dissolution-dynamic nuclear polarization (D-DNP). It can provide signal enhancements by a factor of up to four orders of magnitude in liquid state at room temperature. Combining D-DNP with CP techniques from ¹H to ¹³C can be used to create to create long-lived states (LLS) in deuterated molecules like ethanol-d₆ and DMSO-d₆, which can have much longer life times than conventional Zeeman magnetization. These LLS can be detected indirectly via the asymmetric multiplets in ¹³C NMR spectra in solution state at room temperature after dissolution due to scalar couplings between ¹³C and ²H. These LLS result from population imbalances between spin manifolds of distinct irreducible representations of the relevant symmetry groups of the investigated deuterated moities. In this thesis we have investigated LLS in CD₂ and CD₃ groups. Lifetimes of these LLS can exceed the spin-lattice relaxation times T₁(²H) of deuterium nuclei by a factor up to 20 (depending on the underlying molecular dynamics) and can be obtained by monitoring the decay of the asymmetry of the ¹³C multiplet. These observations can expend the scope of DNP by adding ²H nucleus to the list of possible observables
Botella, Philippe. "Étude du comportement électrochimique des matériaux (316L, Hastelloy C,T60) soumis aux contraintes du traitement hydrothermal des déchets organiques jusqu'au domaine supercritique : adaptation de moyens expérimentaux pour le calcul des vitesses de corrosion et la modélisation de la dissolution passivation en milieu chloruré peu acide." Bordeaux 1, 2000. http://www.theses.fr/2000BOR12238.
Повний текст джерелаMilliard, Alex. "Méthodologie combinant la fusion automatisée à la chromatographie d'extraction pour la dissolution de l'uranium dans des échantillons environnementaux pour la détermination par spectrométrie de masse." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27869/27869.pdf.
Повний текст джерелаRichard, Bruno. "Influence de la physico-chimie des poudres laitières et des conditions opératoires de dispersion sur la dynamique de réhydratation." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10094/document.
Повний текст джерелаThe analysis of rehydration of dairy powders of different composition and different structure (granulated or not) showed the influence of different operating conditions on rehydration, whether an operational point of view (temperature or speed agitation), as a design point of view (geometry of the stirrer). This study allowed to highlight relationships of processes to anticipate the rehydration time necessary to achieve powder dissolution and to better understand the mechanisms of dissolution of dairy and the steps involved from inserting the powder until the end of dissolution. In parallel, the study of ultrasound enabled the development of tools for predicting the ability of a powder to rehydrate on a simple, rapid, and nondestructive test. This technique can also monitor the aging of a powder, significant theme in the use of dairy and having been a pre-study. Finally, calorimetry, a technique with a growing interest in the field of food powders, was also studied in monitoring the ability of powders to rehydrate faster or slower and aging, and showed its limitations for classifying powders in relation to their dissolution ability
Vialle, Stéphanie. "Etude expérimentale des effets de la dissolution (ou de la précipitation) de minéraux sur les propriétés de transport des roches." Paris 7, 2008. http://www.theses.fr/2008PA077175.
Повний текст джерелаOne of the main challenge in the area of the reactive transport in porous rocks is nowadays to identify, develop and test geophysical methods being able to follow, from the surface (and hence at the field scale) the processes that occur inside the rock formation. In this study we have hence sawk to document and better understand the relationships between the dissolution and/or the precipitation of rocks with various textures and mineralogical compositions and the change in the physical parameters (permeability and electrical formation factor). To this end, percolation experiments have been carried out on very well characterized samples and with various injected fluids (oversaturated in calcite in the case of precipitation and rendered acidic by saturation with CO2 in the one of dissolution). The temperature, the pressions, the flow rate, the electrical fluid's and rock's conductivities, the alkalinity, the pH and the chemical composition of the outflow fluid have been followed, that/enables us to have access all the experiment long and in real time both to geochemical (namely alkalinity and calcium's concentrations) and to geophysical parameters (permeability and electrical formation factor). In addition, the results obtained in the laboratory at different scales (centimetric to decimetric) are in good agreement with the ones obtained at a larger scale in the laboratory carrier of the Mayet de Montagne (Mass Central - France)
Cagnon, Benjamin. "Etude fondamentale de la dissolution des silicates amorphes et cristallins : apport à la robustesse des modèles." Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALU012.
Повний текст джерелаThe safety of high-level nuclear waste geological storage is a major scientific and technological challenges of our century. These wastes, inherited from nuclear fuels, are vitrified and stored on production sites (La Hague, Marcoule), waiting on the opening of a storage facility. Their chemical durability is the object of several studies to assess the impact of the release of radionuclides in the environment. Based on this background, this thesis relies on two axes.The first one focuses on the effect of structural disorder on the dissolution of silicates at 90°C, pH 1.5 and 3. Historically, two alteration mechanisms have been identified to explain silicate dissolution: the dissolution–reprecipitation mechanism, generally attributed to crystals, and the hydrolysis–recondensation mechanism, generally attributed to glasses. However, recent studies have shown the need to revisit this dichotomy. To address this point, the dissolution of an amorphous silicate, albite glass, and its crystalline equivalent, albite feldspar, in contact with a solution marked with 29Si was studied. Through the incorporation of this isotope into the altered layer, the contribution of the solution to the formation of the altered layer was quantified to discuss the significance of each mechanism. An antagonistic effect of Al was highlighted as a function of the amorphous and crystalline structure. Moreover, we suggested that the limitation of transport properties within the gel was the key phenomenon controlling the alteration throughout the experiment.The second axis concerns the dissolution of a model glass (International Simple Glass – ISG) in an environment rich in Ca and Si. One of the most likely scenarios for the geological storage site suggests that environmental fluids more or less concentrated in Si and Ca would come into contact with the glass. A 6-oxides glass simulating the nuclear glass was altered in a solution at 90°C, pH > 10. Literature shows that the presence of Ca can have antagonistic effects on the material's dissolution depending on the environment. Among these effects, calcium silicate hydrates (CSH) can precipitate and promote glass alteration.Through the evolution of the dissolution rate, two observations were made: i) the alteration rate is strongly correlated with the solution's saturation state with respect to amorphous silica and ii) the presence of secondary phases, especially CSH, has only a secondary effect on the short-term alteration rate (<20 days). For longer duration experiments, a resumption of glass alteration was observed between 19 days and 76 days, corresponding to a period of CSH growth. After this period, a competition between the formation of CSH and calcium carbonate limited the glass alteration. Finally, the effect of Ca and the transport properties of the gel formed during the first 20 days of alteration were studied in more detail. The addition of calcium to the solution reduces the alteration. Two main effects are discussed: the first consists of a catalytic effect on the recondensation of the gel, and the second on the formation of a (Si, Ca)-rich layer that passivates the gel. It was found that the gel diffusion coefficients based on the tracing experiment were systematically several orders of magnitude lower than those based on the total thickness of the gel. If this difference is partly explained by a variation in temperature, other hypotheses such as i) the evolution of the transport properties of the gel layer during the experiment, ii) a difference in diffusivity between the penetration and release of glass elements within this layer, or iii) a post-mortem restructuration of the gel, are discussed. In conclusion, this work brings several critical information to the understanding of the mechanistic continuum existing between the dissolution of crystalline and vitreous silicates, and of the glass dissolution in chemically relevant environments for long-term geological storage
Devigne, Vincent. "Écoulements et conditions aux limites particulières appliquées en hydrogéologie et théorie mathématique des processus de dissolution / précipitation en milieux poreux." Lyon 1, 2006. http://tel.archives-ouvertes.fr/docs/00/13/20/36/PDF/UCBL_manuscrit.pdf.
Повний текст джерелаCrétaz, Fanny. "Etude de la solubilité et des cinétiques de dissolution des phosphates et vanadates d'uranium : implications pour l'amont du cycle électronucléaire." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20244/document.
Повний текст джерелаIn the current context of restart of the nuclear energy, the needs in uranium are expected to increase significantly. Moreover, in a perspective of sustainable development, the exploitation, the treatment and the purification of uranium ores need to be optimized. It is thus necessary to determine reliable thermodynamic data (and especially solubility constants) for the systems of interest, especially uranium(VI) phosphates and vanadates. In this aim, a multiparametric study of the dissolution of meta-torbernite Cu0.8(H3O)0.2(UO2)2(PO4)2.8H2O, meta-autunite Ca(UO2)2(PO4)2.6H2O, meta-ankoleïte K2(UO2)2(PO4)2.6H2O and carnotite K2(UO2)2(VO4)2.3H2O was undertaken.First, analogues of these four minerals were synthesized, based only on dry chemistry process for carnotite or on wet chemistry methods for the phosphate phases. They were then extensively characterized (in terms of structure, microstructure and chemical composition). It particularly highlighted the similar structures of such compounds. The anionic groups (PO43- or V2O86-) and uranyl form parallel layers between which counter cations (Cu2+, Ca2+ or K+) and water molecules are inserted. However, the counter cations present in the interlayer space of the three phosphate phases present different lability. The synthetic phases were also compared to their natural analogues, except for meta-ankoleïte, which allowed us to point out significant differences in the composition (presence of impurities in natural samples) and the morphology (grain size).The dissolution of these phases was then studied from a kinetic and thermodynamic point of view, through leaching tests in static and dynamic conditions, in various acid media (sulfuric, nitric and hydrochloric) and at different temperatures. In these conditions, the dissolution of meta-autunite was found to be uncongruent due to the precipitation of uranyl phosphate then avoidinf the determination of solubility constants. Similarly, the dissolution of meta-ankoleite was preceded by a cation exchange step between K+ and H3O+ leading to the formation of (H3O)2xK2x-2(UO2)2(PO4)2.6H2O (0 < x < 2) solid solutions, whose solubility constant have been evaluated. Finally, meta-torbernite and carnotite presented congruent dissolutions which allowed the determination of thermodynamic data of interest such as solubility products and standard enthalpy, Gibbs free energy and entropy associated with the dissolution reaction (DrH°, DrG° and DrS°) and formation of each phase (DfH°, DfG° and DfS°).The results obtained evidenced very low and similar solubility constants for the three phosphate phases studied (10-53 < Ks,0° < 10-45). Such small variation directly came from the closely related crystal structures previously described. In addition, the difference in composition of the sheets between phosphate and vanadate phases led to greater stability of carnotite (Ks,0° = 10-63) compared to phosphates phases. The solubility values derived from this study for phosphates and vanadates uranium(VI) allowed estimating values for similar phases. These data were also used in a geochemical model for the prediction of neoformed phases in a real case (water of a lake near an uranium deposit)
Elbiache, Abdelmoula. "Adsorption et ségrégation du soufre sur les alliages Fe-Cr-Ni et Fe-Cr-Ni-Mo : compositions superficielles, dissolution anodique et passivation." Paris 6, 1987. http://www.theses.fr/1987PA066357.
Повний текст джерелаBenzekri, Najoua. "Contribution au developpement de l'electrode disque-anneau en courant alternatif : applications aux mecanismes de dissolution et passivation anodique." Paris 6, 1988. http://www.theses.fr/1988PA066069.
Повний текст джерелаHeisbourg, 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 джерелаShrestha, Binod. "Characterization of lignin thermal processing in a biorefinery perspective." Electronic Thesis or Diss., Université de Lorraine, 2016. http://www.theses.fr/2016LORR0007.
Повний текст джерелаThe thermo-chemical conversion of lignin is an important aspect of lignocellulosic biorefinery in order to produce carbon fibers, polymer additives, green aromatics or biofuels. Protobind 1000 lignin was characterized by thermogravimetry, calorimetry, in-situ rheology, in-situ 1H NMR, solution state 13C and 31P NMR. A multiple techniques including elemental analysis, GPC-UV, FTIR, solid-state NMR and LDI-FTICRMS, were performed to understand the softening and pyrolysis of lignin. An overall physical and chemical mechanism of thermo-chemical conversion of lignin has been proposed. A twin screw extrusion of lignin was carried out using Process 11, following the in-situ high temperature rheology and rheomix internal mixing. The operating window was derived from torque evolution at varying throughputs of 0.1-0.3kg.h-1 and rotation speed of 300-600 rpm at barrel temperature of 150°C for two screw configurations. The lignin extrudates obtained at key extrusion conditions were characterized by FTIR, GPC-UV/ELSD, solution state 1H-13C HSQC NMR. The analysis of lignin melts shows no major structural changes concluding twin screw extruder as a hot melt feeder. The lignin characterization in a liquid media i.e. H2O, ethanol and aq. NaOH, were studied by wet rheology, DLS, zeta potential measurement, SAXS and real-time visual analysis. The lignin liquefaction was carried out in ethanol and the liquefaction products were analysed by UV resonance Raman spectroscopy, GPC-UV and UV-Visible absorption and fluorescence spectroscopy. The structural changes undergone by lignin during liquefaction was accounted
Serre, Christophe. "Contribution à l'étude des mécanismes responsables de la dissolution anodique du silicium en milieu acide fluorhydrique aqueux." Grenoble 1, 1992. http://www.theses.fr/1992GRE10189.
Повний текст джерелаSaldi, Giuseppe. "Les cinétiques de dissolution et de précipitation de la magnésite aux conditions hydrothermales." Phd thesis, Université Paul Sabatier - Toulouse III, 2009. http://tel.archives-ouvertes.fr/tel-00425552.
Повний текст джерелаProvens, Hélène. "Formulation de mousses chimiquement réactives pour la dissolution des oxydes polluant les circuits secondaires des générateurs de vapeur." Montpellier 2, 1999. http://www.theses.fr/1999MON20039.
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 джерелаJeanmaire, Guillaume. "Précipitation des nitrures d’aluminium (AlN) dans un acier maraging à très faible teneur en azote : influence de la déformation plastique à chaud." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0162/document.
Повний текст джерелаThe mechanical properties of the conventional maraging steels are controlled by the choice of chemical composition and appropriate heat treatment parameters; the latter leading to martensitic microstructure and precipitation hardening phases (carbides and intermetallics). In the last decade, this steel family, that mechanical properties are in steady progress, has enabled the development of a new grade of steel, namely: the ML340TM. The performance of the ML340TM is scheduled to meet applications in the aeronautic domain. Despite a strictly controlled chemical composition, requiring very low nitrogen content, aluminium nitride (AlN) can precipitate with particle size up to few tens of microns. The precipitation of these nitrides could be at the origin of micro-cracks formation, which is responsible of the fatigue properties degradation. Improvement of the fatigue property is undoubtedly related to a drastic reduction of the nitrides size. During this study, it was found that the parameters of thermal and thermo-mechanical treatments might have an influence on microstructural features of aluminium nitrides: mass fraction, surface density, size and spatial distribution. This task was made possible thanks to the introduction of an automated method coupling the image analysis to the chemical composition. This unusual method allows discriminating, by size and by chemistry, aluminium nitrides from the other particles (carbides inclusion, etc.). The role of some of the heat treatment parameters (cooling rate, time and isothermal holding temperature, intermediate and direct quenching) on the microstructural features of aluminium nitrides has been clearly identified. Furthermore, hot plastic deformation, in the austenitic range, has a highlighted effect on the microstructure features of the aluminium nitrides. Ultimately, in this study, we have revealed that getting a submicron aluminium nitride precipitation is subjected to a controlled combination of thermal and thermo-mechanical parameters
Jiang, Chongjun. "Etude des alternances récurrentes dans les skarns et des instabilités du front de dissolution/précipitation." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 1993. http://tel.archives-ouvertes.fr/tel-01052909.
Повний текст джерелаChen, Tao. "Evolution de la perméabilité d'agrégats de sels sous contrainte liée à des circulations de fluides : dissolution, colmatage, déformation." Phd thesis, Université Joseph Fourier (Grenoble), 1994. http://tel.archives-ouvertes.fr/tel-00743930.
Повний текст джерелаESTRADA, MALDONADO C. FABIOLA. "Contribution a l'etude du systeme ca-mg-co#2-h#2o : dissolution de la calcite et de la dolomite dans l'eau de mer et dans des solutions de nacl de 0 a 300c." Toulouse 3, 1991. http://www.theses.fr/1991TOU30223.
Повний текст джерелаMailleur, Alexandra. "Évaporation de goutte sur substrat soluble." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1268/document.
Повний текст джерелаRecent progresses have led to a better understanding of the mechanisms driving the evaporation kinetics of a sessile droplet of simple liquid on an inert substrate. For instance, the influence of the contact angle of the droplet, of the thermal conductivity of the solid, of its roughness, of the thermocapillary convection inside the droplet, or of the convection in the vapor are now better understood. Besides, the way coffee-stain-like deposits form during the evaporation of complex fluids (colloidal suspension, blood …) has now been studied in detail.All these studies have been carried out with non-reacting solids. We propose here the investigation of the behavior of a water droplet evaporating on a soluble substrate. In this configuration, three phenomena are strongly interacting: dissolution/precipitation of the substrate at the solid-liquid interface, diffusion/convection of the dissolved species in the droplet, evaporation of water at the liquid-air interface. We have worked with fast-dissolving solids, NaCl and KCl single crystals, with controlled temperature and humidity. To test the influence of thermogravitational instabilities, experiments on the ground and in microgravity (parabolic flights) have been carried out.We have observed that the dissolution induces a pinning of the triple line at the early beginning of the evaporation, leading to a decrease of the contact angle linear in time. At the end of the evaporation, a peripheral deposit (coffee-ring-like) resulting from the salt migration and precipitation, is always present, proof of an outward flow inside the droplet. The observation of drops seeded with fluorescent particles evaporating on a dissolving solid (NaCl single crystal) has highlighted complex capillary flows inside the liquid. The shape of this ring-like deposit is very diversified and vary with the substrate temperature and the initial volume of the droplet
Rebiere, Jérémy. "Nouvelle méthodologie pour la caractérisation de distributions de masses molaires d'échantillons cellulosiques complexes." Thesis, Toulouse, INPT, 2017. http://www.theses.fr/2017INPT0017/document.
Повний текст джерелаCellulose is a very abundant natural biopolymer. According to its origin and to its extraction mode, it presents various cristallinity rate and molar mass. Its organization relies mainly on intermolecular hydrogen bonds that form a strong network and thus limitating cellulose solubility. Complete andnon-degradative dissolution is then complicated and depends on the solvent ability to disrupt these hydrogen bonds. Analysis of the molar mass distribution (MMD) of cellulose by size exclusion chromatography (SEC) of cellulose is consequently problematic while the study of the evolution of cellulose molar mass during transformations could be extremely useful in many processes. The most common solvent used in SEC is lithium chloride/N,N-dimethylacetamide (LiCl/DMAc), which is extremely toxic. The aim of this PhD study is then to develop a new analytical method to characterize cellulose MMD using safer solvents and adapted to all kinds of cellulosic sample. Among the numerous non-derivatizing solvent systems described in the literature, three of themhave been selected. Greener and less toxic than LiCl/DMAc, their ability to dissolve cellulosic sample of various cristallinity and average molar mass without degradation was then tested. Thermogravimetric analyses and viscosimetric studies allowed to evaluate and to compare the modifications involved by the dissolution for four different cellulosic samples. LiCl/DMAc degraded the samples of higher molar mass (-cellulose and Vitacel) decreasing their degree ofpolymerization by 50 % after dissolution. Tetrabutylammonium/dimethylsulfoxide (TBAF/DMSO) system allows rapid dissolution of the 4 cellulose samples, without major degradation or modification. TBAF/DMSO system was then studied as solvent for SEC analysis of these cellulose samples. Due to the interactions between the aromatic groups composing the stationary phase with TBAF molecules, the complete system could not be used as eluant. Chosen eluant was then DMSO alone. However, as the TBAF molecules are mandatory for the dissolution of cellulose, TBAF concentration was adapted according to the cellulose nature for the preparation of the samples. For low molar mass cellulose samples, a TBAF concentration of 1 %(w/v) was sufficient and allowed to performed correctly the chromatographic analysis. For the samples of higher molar mass, this concentration was not high enough to complete the dissolution. Using, higher concentrations caused aggregation phenomena resulting in the elution of a large amount of the macromolecules in the dead volume, as observed with the analysis of pullulan standards
Berger, Pascal. "Etude du mecanisme de la dissolution par oxydoreduction chimique et electrochimique des bioxydes d'actinides (uo2, npo2, puo2, amo2) en milieu aqueux acide." Paris 6, 1988. http://www.theses.fr/1988PA066073.
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
Bettayeb, Mohamed. "Etude des relations entre résistance à l’amorçage de la corrosion intergranulaire et structure des joints de grains sur cuivre polycristallin." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEC018.
Повний текст джерелаEtude des relation entre microstructure et phénomènes liés à l'initiation de la corrosion intergranulaire. notre stratégie et l’étude des surface de cuivre polycristallin par microscopie à champs proche et en ebsd