Дисертації з теми "Poudre en suspension"
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Jacquelin, Marjorie Gehin Evelyne. "Étude de la mise en suspension de particules par chute de poudre." Créteil : Université de Paris-Val-de-Marne, 2008. http://doxa.scd.univ-paris12.fr:80/theses/th0407082.pdf.
Jacquelin, Marjorie. "Étude de la mise en suspension de particules par chute de poudre." Paris 12, 2007. http://www.theses.fr/2007PA120042.
This study comes within the general framework of industrial facilities’ safety research. Indeed, industrial processes, notably in the nuclear field, handle hazardous materials in powder form and can produce large quantities of fugitive dust. The study of the particles resuspension from powders is of interest of first order in order to estimate the consequences of this source term of contamination on the operator, the neighbouring installations and, if necessary, the environment. Up to now, there are very few reliable data in the scientific literature on the particulate emission in case of a scenario with an accidental free fall spill of powder. The powder dustiness evaluation is carried out using coefficients obtained in experiments, or using empirical correlations. The objective of the present work is to study the influence of some parameters involved in the airborne particles production by a free fall of powder. For that purpose, experiments are carried out in order to study the influence of parameters such as the type of dischargement, the powder nature, the type of surface on which occurs the powder impaction , the system diameter used for discharge, and the falling mass. The results of mass fractions and number concentrations obtained highlighted the dominating parameters according to the type of discharge employed. Thereafter, the comparisons between our results and the empirical correlations available in the literature showed that those led to an undervaluation of the powder dustiness. This thus led us to develop, starting from the whole of experimental data, empirical correlations taking into account the various parameters studied as well as the interactions
Tiabi, Nadia. "Synthèse de préformes dopées ytterbium par voie poudre pour la réalisation des lasers à fibre de haute puissance." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0049.
The work presented in this manuscript is part of a PhD thesis carried out by CIFRE in collabora-tion between the laboratory of Xlim and the technological center of optics and lasers "ALPhA-NOV". The main objective of this thesis is to design ytterbium doped preforms that are resistant to the photodarkening (PD) phenomenon for use in high power laser applications.This phenomenon degrades laser performance and leads to reduced output. Two main areas are focused in this thesis. The first is the definition of the core composition and the appropriate synthesis method for the production of preform cores which are resistant to photodarkening (PD). The second is to develop, characterize and evaluate the optical performance of the resulting fiber. The matrix that has been chosen for the study is the alumino-phosphosilicate matrix. To obtain this matrix, a synthesis method called "powder in suspension" was used.From the synthesis of the preform to the drawing of the optical fiber, the different stages of the process have been validated. Excellent performance, with low attenuation of 0.1 dB/m and a very promising optical-to-optical conversion efficiency of 76%, was obtained from the optical tests performed on the fiber. The evaluation of the fiber against photodarkening showed an exceptional resistance. No performance degradation was observed over 100 hours
Ravaux, Alice. "Réalisation et étude de dépôts composites multi-échelle élaborés par projection plasma pour applications tribologiques à hautes températures." Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0077/document.
Nowadays, tribology has a high energetic impact on economic and industrial areas. Thus, reducing wear and friction of mechanical parts has become a real stakes for various industries. This study is focused on the wear prevention of mechanical parts subjected to severe operating conditions like high temperatures.The realization of protective ceramic-metal coatings is thus particularly appropriated to improve corrosion resistance induced by the high temperatures, with a suitable alloy, and the wear resistance, thanks to the ceramics hardness. Furthermore, researches development in the nanoscale field have shown the interest of scale reduction on the improvement of coatings tribological properties. Thermal spraying is then the most appropriate process for the realization of such coatings.In this work, multi-components (ceramic-metal) and multi-scales (micrometric-nanometric) coatings are developed by plasma spraying in order to give an answer to the high temperature tribological resistance issue. Coatings are realized using a three-cathodes plasma gun (TriplexPro-200) which provides a more stable plasma jet and offers wide possibilities by an extended operating window. First, the special features of this kind of plasma gun will be studied in order to adjust the process to the complex realization of multi-scale coatings. An innovative approach using a hybrid spraying process was thus developed, combining conventional micrometric powder spraying and suspension of nanoscale powders spraying. In a second time, the steps leading to the production of such coatings will be detailed, and finally, their main properties and their tribological behavior will be studied
Ramenatte, Nicolas. "Fonctionnalisation de surface de l’Inconel 625 élaboré par fabrication additive par fusion de lit de poudre." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0093.
Currently the development of hydrogen mobility is hampered by the sizes of plants that cannot produce small volumes as close as possible to the distribution points. The emergence of metallic additive manufacturing gives the opportunity to develop compact equipment whose size will make it possible their installation as close as possible to the users. These thesis works are performed in the frame of the project FAIR (Additive manufacturing for the intensification of the reactors). They aim on one hand at developing reactors-exchangers based on the Inconel 625 elaborated by the laser beam melting (LBM) technology, and on the other hand at functionalizing the surface to improve their resistance against Metal Dusting corrosion, making these equipments compatible with their industrialization. Two ways have been followed in this work. The first one is focused on the study of the microstructure of these new materials and its evolution during heat treatment. The second one aims to assess the reactivity of these new materials in oxidizing atmosphere. Several areas of the LBM material have been characterized: the core, the subsurface and the surface zone with important roughness. The heterogeneity of the solidification structure and the associated chemical segregations have been observed. The microstructure of the core alloy is partially restored as elaborating. During the heat treatment, the stored energy induces a structural rearrangement (recrystallization) favoring the formation of special grain boundaries like twinned grain. The influences of temperature (1075 and 1160 ° C) and time of heat treatment on the mechanisms underlying this microstructure evolution have been studied. Although the raw microstructure provides an oxidation resistance at 900°C equivalent to a conventional material (alloy inconel 625 lamited), oxidation of LBM alloy is catastrophic from 125h at 1050°C whatever the surface roughness or the microstructure. These difference cannot be improved with a thermal pre-treatment. An oxidation mechanism, taking into account the microstructural state of the material, has been developped enabling the description of the morphology of the oxidation products as well as the measured oxidation kinetics
Catalot-Martinent, Valérie. "Étude de suspensions ciment alumineux-eau : corrélations rhéologie-granularité-compacité." Grenoble INPG, 1997. http://www.theses.fr/1997INPG4209.
Do, Anh Lam. "Approche LPV pour la commande robuste de la dynamique des véhicules : amélioration conjointe du confort et de la sécurité." Electronic Thesis or Diss., Grenoble, 2011. http://www.theses.fr/2011GRENT114.
This work concerns the development of advanced control methods for automotive suspensions to improve road holding and passenger comfort, while satisfying the technological constraints related to the suspension actuators (passivity, nonlinearity, structural limit). In the first part, we propose two control schemes by polytopic LPV (Linear Parameter Varying) approach and by Strong Stabilization with genetic algorithm optimization to solve the comfort/handling and comfort/suspension travel conflits. In the second part, to solve the full semi-active suspension problem, we develop first a generic strategy for general LPV systems subject to actuator saturation and state constraints. The problem is studied in the form of resolution matrix of linear inequalities (LMI) that allows synthesizing an LPV controller and an anti-windup gain to ensure the stability and performance of the closed-loop system. Second, the theoretical result is applied to the case of semi-active suspension control. The proposed methods are validated by an evaluation based on an industrial standard and simulations on a nonlinear quarter vehicle model
Do, Anh Lam. "Approche LPV pour la commande robuste de la dynamique des véhicules : amélioration conjointe du confort et de la sécurité." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENT114/document.
This work concerns the development of advanced control methods for automotive suspensions to improve road holding and passenger comfort, while satisfying the technological constraints related to the suspension actuators (passivity, nonlinearity, structural limit). In the first part, we propose two control schemes by polytopic LPV (Linear Parameter Varying) approach and by Strong Stabilization with genetic algorithm optimization to solve the comfort/handling and comfort/suspension travel conflits. In the second part, to solve the full semi-active suspension problem, we develop first a generic strategy for general LPV systems subject to actuator saturation and state constraints. The problem is studied in the form of resolution matrix of linear inequalities (LMI) that allows synthesizing an LPV controller and an anti-windup gain to ensure the stability and performance of the closed-loop system. Second, the theoretical result is applied to the case of semi-active suspension control. The proposed methods are validated by an evaluation based on an industrial standard and simulations on a nonlinear quarter vehicle model
Vu, Tuyet-Oanh. "Dispersion d'une poudre dans un liquide : caractérisation des interactions interfaciales et effets de différents facteurs sur la vitesse de dispersion." Saint-Etienne, EMSE, 2002. http://www.theses.fr/2002EMSE0029.
The aim of this work is to study a powder/liquid system for instantizing a powder in a liquid. The model powder chosen, cocoa, and its interaction with water were characterised to determine the dispersion behaviour. Contact angles and adhesion forces were measured by the sessile drop method and by a modified Washburm method. Water is a non-wetting liquid with respect to cocoa powder. Dispersion kinetics were measured by using an optical fibre detector. The most significant parameters on dispersion speed were the power of the agitation and the rise in temperature. Granulated powder was prepared by two processes : atomisation and high shear granulation. Atomisation lead to better dispersion while high shear granulation gave granules having an increased speed of dispersion
Ben, Romdhane Mohamed Ramzi. "Nouveaux auxiliaires organiques pour le pressage de poudres d'alumines atomisées." Limoges, 2005. http://aurore.unilim.fr/theses/nxfile/default/5505a06a-ec3e-49da-8347-8c14e89e78c2/blobholder:0/2005LIMO0016.pdf.
The forming of advanced ceramics generally requires the use of organic additives, in order to confer to the system desired properties of flow and cohesion. The introduction of different organics in the ceramic suspension often involves interactions not only between the additives and the particles but also between the additives themselves. In the spray-drying process of powders for die pressing, the weak adsorption of the binder in comparison to that of the dispersant generates a heterogeneous distribution of the organic phase in the ceramic green part. The aims of this study is the definition and the synthesis of new polymers, which would carry two functions in order to confer both the role of binder and dispersant. A particular attention is paid in on hand, on the comprehension of the phenomena of interaction between these copolymers and the surface of the alumina powders in aqueous suspension with the study of the adsorption isotherms, the electrokinetic and rheological properties and, in the other hand, on the effect of these interactions on the state of dispersion of the powders. The mechanical properties of green parts pressed using spray dried powders with the synthesized copolymers are evaluated and discussed according to the nature copolymers
Faure, Fabien. "Suspension magnétique pour volant d'inertie." Grenoble INPG, 2003. http://www.theses.fr/2003INPG0079.
Chernoburova, Olga. "Étude des interactions entre les particules fines dans les suspensions concentrées pour améliorer la valorisation de minerais complexes durable." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0272.
Fine particle mineral slurries are known to exhibit non-Newtonian behavior under the load. The particle-particle interactions in such suspensions go beyond physical contact due to the collision and friction. An ability of minerals to gain the charge in the aqueous environment justifies different behaviors of the similar systems. Being characterized with the same volumetric fraction, chemistry and particle size distribution of solids, and specific gravity of dispersing media, two suspensions can possess different rheological behavior due to the chemistry of the solution. In this case, the ionic composition of the media defines particle charging, and thus the degree of agglomeration/dispersion in the suspension. Phyllosilicate clays are known to be particularly problematic in the mineral beneficiation processes. Their nature leads spatial chemical inhomogeneity, meaning that the particle edge and face possess different chemical and physical properties. The presence of such minerals in the stirring devices (stirring tanks, flotation cells) is often characterized with coexistence of stagnant and agitated volumes of slurry, which negatively impacts the efficiency of stirring. In this work, the dilute aqueous Na-bentonite suspensions were examined via magnetic resonance imaging velocimetry to investigate the influence of pH and type of monovalent electrolyte on their local rheological behavior. The results indicated that suspensions with 0.1 vol.% solid can exhibit shear banding, shear localization or no local phenomenon as a function of chemistry of the suspending media. It was suggested that the existence of master curve (or global flow curve) for dilute suspensions was dependent on the bentonite particle organization in the suspension, which was influenced by the chemistry of the environment and the previous flow history. In the next step, second mineral phase (hematite or quartz) was added to the bentonite matrix. The interest in examination of such systems is related to the flow behavior of matrix formed with different kinds of inter-particle contacts. For example, at pH 4 the resulting electrostatic interaction between positively charged bentonite edge and negatively charged quartz is attractive, whereas at the same pH it is repulsive with the positively charged hematite. These electrostatic interactions result in different organization of matrix particles around another mineral phase. In the system with solely repulsive interactions between all sites of all mineral phases (e.g., quartz and bentonite, pH 10) the deviation from Newtonian behavior is justified by the shear-induced particle rearrangements, collision and friction. The difference in the arrangement of bentonite particle aggregates around the hematite or quartz particles was observed using SEM. As a next step the third mineral phase was added. The types of contacts established in the suspensions with different chemistry of the media were discussed along with their flow propperties
Leylavergne, Maryse. "Rechargement par plasma d'arc tranféré de substrats d'alliages (base fer et base nickel) recouverts de films métalliques déposés par coulage en bande." Limoges, 1999. http://www.theses.fr/1999LIMO0032.
Chassoulier, Damien. "Suspension magnétique pour roue d'inertie orientable." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0079.
Wattieaux, Gaëtan. "Détection et métrologie de nanoparticules en suspension dans un plasma froid basse pression." Thesis, Orléans, 2010. http://www.theses.fr/2010ORLE2080.
The recent development of nanotechnology has made nanoparticle sizing more and more important for the quality of manufactured products as well as for human health and environmental protection. The aim of this thesis was to look for innovative solutions to measure the size and the concentration of nanoparticles in dry environnement. To meet this requirement we focused on the physics of dusty plasmas because the desagglomeration of a powder sample is enhanced when it is exposed to a plasma and the dusts modify signifcantly the electrical properties of the plasma where they are trapped. The first result of this work is the determination of the mean size of dusts that are injected or formed in a RF low pressure capacitive discharge from the variations of the electrical parameters of the plasma and of the discharge. A new particle sizing technique has also been developed. It consists of determining the powder size distribution from the measurement of its sedimentation speed following the extinction of the discharge. The system that has been designed was successfully used to monitor in real time a nanopowder production line based at the CEA Saclay
Chernoburova, Olga. "Étude des interactions entre les particules fines dans les suspensions concentrées pour améliorer la valorisation de minerais complexes durable." Electronic Thesis or Diss., Université de Lorraine, 2018. http://www.theses.fr/2018LORR0272.
Fine particle mineral slurries are known to exhibit non-Newtonian behavior under the load. The particle-particle interactions in such suspensions go beyond physical contact due to the collision and friction. An ability of minerals to gain the charge in the aqueous environment justifies different behaviors of the similar systems. Being characterized with the same volumetric fraction, chemistry and particle size distribution of solids, and specific gravity of dispersing media, two suspensions can possess different rheological behavior due to the chemistry of the solution. In this case, the ionic composition of the media defines particle charging, and thus the degree of agglomeration/dispersion in the suspension. Phyllosilicate clays are known to be particularly problematic in the mineral beneficiation processes. Their nature leads spatial chemical inhomogeneity, meaning that the particle edge and face possess different chemical and physical properties. The presence of such minerals in the stirring devices (stirring tanks, flotation cells) is often characterized with coexistence of stagnant and agitated volumes of slurry, which negatively impacts the efficiency of stirring. In this work, the dilute aqueous Na-bentonite suspensions were examined via magnetic resonance imaging velocimetry to investigate the influence of pH and type of monovalent electrolyte on their local rheological behavior. The results indicated that suspensions with 0.1 vol.% solid can exhibit shear banding, shear localization or no local phenomenon as a function of chemistry of the suspending media. It was suggested that the existence of master curve (or global flow curve) for dilute suspensions was dependent on the bentonite particle organization in the suspension, which was influenced by the chemistry of the environment and the previous flow history. In the next step, second mineral phase (hematite or quartz) was added to the bentonite matrix. The interest in examination of such systems is related to the flow behavior of matrix formed with different kinds of inter-particle contacts. For example, at pH 4 the resulting electrostatic interaction between positively charged bentonite edge and negatively charged quartz is attractive, whereas at the same pH it is repulsive with the positively charged hematite. These electrostatic interactions result in different organization of matrix particles around another mineral phase. In the system with solely repulsive interactions between all sites of all mineral phases (e.g., quartz and bentonite, pH 10) the deviation from Newtonian behavior is justified by the shear-induced particle rearrangements, collision and friction. The difference in the arrangement of bentonite particle aggregates around the hematite or quartz particles was observed using SEM. As a next step the third mineral phase was added. The types of contacts established in the suspensions with different chemistry of the media were discussed along with their flow propperties
Schmandt, Claire-Annie Brouillaud Jean-Pierre. "La suspension de peine pour raisons médicales." [S.l.] : [s.n.], 2006. http://edoctorale74.univ-lille2.fr/fileadmin/master_recherche/T_l_chargement/memoires/penal/schmandtca06.pdf.
García, Pérez Pascual. "Hétérocoagulation de poudres d’oxydes en milieu aqueux : étude d’un processus d’agglomération pour l’élaboration de sphères en suspension." Limoges, 2007. https://aurore.unilim.fr/theses/nxfile/default/f3d0be72-fa17-42ac-8c31-c9334fa3fb3f/blobholder:0/2007LIMO4001.pdf.
This work is focused on the study of the interactions between two inorganic materials, alumina and silica. When the two partially dispersed suspensions of these two oxides are mixed, the surface charge with an opposed polarity produces an heterocoagulation process in a large range of pH. Nanoparticles of silica adsorb on the submicronic alumina surface. An adapted mass relationship between the two oxides destabilizes the system and agglomerates alumina. The application of a rotational movement to the suspension bottle increases the agglomerates size with time. The consolidation of the suspension leads to a very homogeneous distribution of spheres in terms of size and form. This process was extended to others raw materials like zirconia, silica or titanium oxide. Hollow spheres was also obtained
Castel, Aude. "Électrochimie en milieux hétérogènes : synthèse, électroactivité et applications redox de quelques suspensions aqueuses de poudres métalliques." Rennes 1, 2007. http://www.theses.fr/2007REN1S006.
This manuscript relates to the electrochemical study of heterogeneous media made up of iron, zinc or copper powders in a suspension of aqueous media. A voltammetric study showed that the activity of solid particles at an electrode depends on the nature of the electrode and of the particle. The modification of the electrode surface by a conductive film of polyaniline allowed the observation of an electrochemical activity of a few conductive suspensions (metal or carbon particles). The electrodeposition of copper, iron and zinc was studied in two types of heterogeneous media : solid / liquid or solid / gas. The formation of cathodic hydrogen promotes an important but fragile metal coating. This observation was put to use for the synthesis of metal powders by a process using a soluble anode. An electrolytic reactor for the production of zinc and iron powders was then finalized. These synthesized metal powders revealed to be much more reactive than powders ordinarily sold in the application of electrocatalyzed denitratation
D'Ambrosio, Enzo. "Imagerie de suspensions pour la mesure des contraintes particulaires dans les suspensions non-browniennes." Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4045.
Many studies have been done on the rheology of suspensions since the previous work of Einstein at the beginning of the 20th century but many scientific puzzles still remain, especially when the concentration increases. Nowadays, we know that the solid contact between particles rules the behavior of non Brownian concentrated suspensions : it increases the viscosity, inducesbehavior more complex than the basic Newtonian model and are responsible for phenomenon of migrations of solid particles inside a suspension. Naturally, theoretical models as the Suspension Balance Model which predict and describe the behavior of a sheared non Brownian suspension deals with these non hydrodynamic interactions. But there is a lack of experimental measurements to confront these predictions. Indeed, it is very difficult to measure experimentally the contribution of solid particles to the total stress of suspension and this is precisely what I’ve tried to do during these last three years. I’ve organized my work following two lines of research. The first one is a macroscopic study of the rheological behavior of different suspensions where the particle form varies from a suspension to another. Therewith, I show that non-Brownian and non-colloidal suspensions have a shear thinning behavior which can be correctly captured by the introduction of a jamming volumefraction which is shear stress-dependant. The second line of research is the biggest part of my work. Thanks to an experimental home-made set up, I study locally the behavior of a non Brownian suspension in two cases : with or without buoyancy effects. Matching the refractive index of the particles and of the fluid, I manage to image the particles inside the suspensions subjected to a shear flow in order to determine the concentration and the velocity fields. From these local measurements, I deduce on the one hand the variation of the shear viscosity with particle volume fraction and shear stress and, on the otherhand the variation of the normal particle stresses in the direction of the velocity gradient and the vorticity. I also show that there are significant differences in the flow of a suspension depending on whether gravity plays a role or not. More precisely, I show that the radial migration observed in a cylindrical large gap Couette flow is much less pronounced than what the Suspension Balance Model predicts if the particles do not have the same density as the suspending liquid
Boissière, Benjamin. "Étude hydrodynamique et thermique d'un nouveau concept de récepteur solaire à suspensions denses gazparticules." Phd thesis, Toulouse, INPT, 2015. http://oatao.univ-toulouse.fr/13944/1/boissiere.pdf.
Walesch, Dieter. "Étude de la mise en suspension de poudres d'aluminium dans un milieu liquide en vue de réaliser des dépôts d'aluminium sur tôles galvanisées." Valenciennes, 1997. https://ged.uphf.fr/nuxeo/site/esupversions/9a67be5e-54d4-431d-be0f-fe42d2dd61ca.
Odet, Margot. "Étude biomécanique d’une suspension implantable pour la préservation des disques intervertébraux dans le traitement des scolioses infantiles." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1135/document.
Infantile scoliosis is a progressive spinal deformity occurring in children under 3 years-old. The most common currently correction technic is the "growing rods" one. However, the implant rigidity causes intervertebral discs degeneration, which decreases the treatment efficiency. Recent studies have shown the benefic effect of flexible implants on discs. Our team has developed the concept of an implantable suspension that keeps the axial mobility of the instrumented segments, associated with a new fastening ball joint system. However, which is the stiffness value that preserves discs while correcting scoliosis? This thesis goal is to demonstrate the effectiveness of a suspension device for preserving inter-vertebral discs health and obtain quantifiable information on the optimum stiffness value. Prototype suspensions with ball joint fastenings, implantable in quadruped mammals and humans, have been de-veloped to study several ranges of stiffness values in vivo and in silico. An in vivo study on healthy adult goats was conducted to test these prototypes for two different stiffness values. The intervertebral discs health after 6 months was evaluated by MRI and histological sections. In parallel the biomechanics of a human spine was studied with a rigid multi-body numerical model previously validated against in vitro literature data. Healthy and scoliosis subjects instrumented with different devices (traditional rods, sus-pensions, with or without the ball) were modeled. The results of the in vivo study showed no significant difference between the several instrumen-tations. A longer test time seems necessary to observe the onset of disc degeneration. Numerical simulations have shown a marked mobility improvement for the segments in the in-strumented area with a suspension device associated with a ball joint system. However, the majority of the mobility is provided by the new fixing system and not by a greater axial flexibility. The suspension still allows additional gain for certain spine movements. No significant differences were found between the two studied stiffness values. The presence of a ball joint fastening decreases strongly the correction obtained during surgery distraction simulations. The suspension has an interest during correction by reducing the forces trans-mitted to the material when used alone. Future developments thus would lead to a suspension device associated with ball joint fasten-ings that also have rotational stiffness to keep both good scoliosis correction and segments mobility
Bergougnoux, Laurence. "Diagnostic optique pour la mesure de concentration de matières en suspension." Aix-Marseille 1, 1995. http://www.theses.fr/1995AIX11060.
Goalard, Carol. "Étude physico-chimique du procédé de dispersion des poudres libres et agglomérées en milieu liquide." Toulouse, INPT, 2005. http://ethesis.inp-toulouse.fr/archive/00000411/.
The dispersion of powders in liquids is a process widely used in industry and in every day life. The requirement to disperse a powder in a liquid rapidly and uniformly where the quality of the dispersion will define the quality of the final product. The optimisation of the process requires knowledge of the influence of the parameters on the kinetics of dispersion. To better understand the different energies involved, the process of dispersion may be divided into three stages : adhesion, immersion, and spreading. These stages can be examined as a function of the solid/liquid interfacial energy, the surface energy of the solid and the energy required to stir the liquid. A experimental device, with en optical fibre is used to characterise the dispersion. This technique allows the determination of the effects of various parameters on the operation
Goalard, Carol Dodds John. "Étude physico-chimique du procédé de dispersion des poudres libres et agglomérées en milieu liquide." Toulouse : INP Toulouse, 2007. http://ethesis.inp-toulouse.fr/archive/00000411.
Loubière, Sophie. "Elaboration et caractérisation de poudres et de suspensions électrolytiques. Application à la fabrication de revêtements composites." Toulouse 3, 1996. http://www.theses.fr/1996TOU30209.
Henni, Becherif Assia. "Analyse de la robustesse de la stabilité pour des systèmes non linéaires dynamiques." Paris 11, 2004. http://www.theses.fr/2004PA112182.
This work deals with the problem of stability robustness analysis of nonlinear systems with bounded uncertainties. On the basis of L2-gain analysis and small-gain theorem, this problem may be characterized by HJI. The HJI conditions are expressed in terms of nonlinear matrix inequalities (NLMI) which are convex. The NLMI conditions involve neither a finite number of unknowns nor finite number of constraints. Despite of the existing attempts, the NLMI numerical resolution still remains a difficult problem. Therefore, it is herein proposed to reformulate the problem in order to suggest more exploitable methods in the case of the affine nonlinear systems. We then propose an easier possible way to overcome the difficulty encountered by the NLMI characterization by using the notion of dissipation, in the case of nonlinear systems with bounded unstructured uncertainties. The stabilization of a spacecraft during vertically descent on the surface of a planet with bounded unstructured uncertainties is given as illustration. The obtained simulation results are shown to be in concordance with the required performance. However in the case of nonlinear systems with bounded structured uncertainties, it has been proposed a new way for the stability robustness analysis. As application, we have applied the nonlinear backstepping based approach to deal with the problem of stabilizing a magnetic suspension device with bounded structured uncertainties. Numerical simulations as well as experimental results have been performed and are shown to be satisfactory
Maitrejean, Guillaume. "Couplages moléculaire- théorie cinétique pour la simulation du comportement des matériaux complexes." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENI067/document.
This work is a contribution to the numerical modeling of suspension system in the kinetic theory framework. This continuum description of suspension system allows to account for the microstructure impact on the kinetic of the macroscopic flow. However, its main drawback is related to the high dimensional spaces in which kinetic theory models are defined and makes difficult for classical deterministic approaches to solve such systems. One possibility for circumventing, or at least alleviate, the weight of the micro-macro kinetic theory approaches lies in the use of separated representations strategies based on the Proper Generalized Decomposition (PGD). A study of different PGD algorithms is driven, illustrating the efficiency of these algorithms in terms of convergence speed and optimality of the solution obtained. The immiscible fluids blends modeling is driven using the area tensor which is a powerful numerical tool for characterizing blends. However it needs the introduction of closure relation of which impact is measured using equivalent and exact kinetic theory model. Finally, the numerical modeling of colloidal suspension system described by the Smoluchowski equation presents an original approach of the modeling of solid suspension system. This description allows to circumvent the statistical noise inherent to the stochastic approaches commonly used
Pizarro, Céline. "Développement d'un amortisseur multi-plages pour la suspension des motoneiges Ski-Doo." Mémoire, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6204.
Lafourcade, Pascal. "Étude des manipulateurs parallèles à câbles : conception d'une suspension active pour soufflerie." Toulouse, ENSAE, 2004. http://www.theses.fr/2004ESAE0012.
Sleiman, Hussein. "Systèmes de suspension semi-active à base de fluide magnétorhéologique pour l’automobile." Paris, ENSAM, 2010. http://www.theses.fr/2010ENAM0020.
In the automotive field, semi-active suspensions based on magnetorheological (MR) fluid put forward a very interesting compromise between high performance and low power consumption. These devices have adjustable properties and damping parameter that can be controlled thereby optimize in real time their behavior over a wide frequency range of excitations. Under an external magnetic field, the MR fluids see their viscosity increases, with a response time lower than few milliseconds. In this dissertation, we present the design of a MR damper and an experimental test bench for a scaled-down semi-active suspension. The static and dynamic characterization of the damper is shown. Experimental evaluation of the damping force according to dynamic and electrical variables is presented and compared with the specifications used to assess the design method proposed. A Bingham model is proposed for the static behaviour of the damper whereas the dynamic behaviour is explained by a Bouc-Wen model. The last part of this study concerns the development and validation of several control and strategy laws for semi-active suspensions, in particular innovative laws based on model inversion EMR. A comparison performances study from comfort and power consumption point of view of each law is presented. Compared to existing control laws, these new control laws shown very interesting performances while reducing power consumption
Fillion, Alain. "Anesthesie generale pour laryngoscopie en suspension : interet de l'association etomidate-diazepam-fentanyl." Lyon 1, 1989. http://www.theses.fr/1989LYO1M027.
Saint-Raymond, Hubert. "Etude de l'agglomération par turbidimétrie de poudres d'alumine en milieu liquide." Grenoble INPG, 1995. http://tel.archives-ouvertes.fr/tel-00843295.
CAVIGNEAUX, DECOURTEIX-TURQUET ISABELLE. "Techniques chirurgicales dans la suspension palpebrale pour la cure du ptosis : etude a propos de 6 cas personnels." Limoges, 1988. http://www.theses.fr/1988LIMO0152.
Fergani, Soheib. "Commande robuste LPV/H infini multivariable pour la dynamique véhicule." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT053/document.
The main issue of this thesis is to work out new Global Chassis MIMO controllers that enhance the overall dynamics of the vehicle while preserving the vehicle stability in critical driving situations. Many innovative strategies have been explored and finalized to deal with these problematics. Various solutions have been given to deal with the vehicle stability and performance objectives. Indeed, many works based on the LPV/Hinf approach have been developed to control simultaneously the braking, steering and suspension actuators. On the other hand, innovative road profile estimation strategies have been introduced and validated via experimental procedures, providing new cheap and easily implementable techniques to estimate the road profile characteristics. Then, the vehicle control is adapted, depending on the road roughness (since it influences greatly the behaviour and the stability of the car). Several fault tolerant control strategies have been also considered to handle the actuators failures while keeping the vehicle stability, safety and enhancing the dynamical behaviour of the car in dangerous and critical driving situations.The general content of this thesisis as follows :-PART I : Theoretical backgrounds and vehicle modeling.-PART II : Road adaptive control vehicle dynamics.-PART III : Global chassis control using several actuators.Also, during this thesis and using the previous works of the advisors and the thesis results, a Matlab ToolBox "Automotive" has been developed to provide a bench test for the different automotive control studies. Implementations on test beds and real vehicle are also achieved to prove the efficiency of the proposed strategies
Nguyen, Van Nga. "Microsphères résorbables pour embolisation et chimio embolisation." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA114808/document.
Therapeutic embolization is nowadays a first line treatment for haemorrhage, arteriovenous malformation or tumors. Among different embolization agents, non degradable microspheres(Embozene®, Bead BlockTM,…) are the most employed thanks to their well calibrated spherical shape which allows good occlusion. In some cases including treatment of uterine fibroids or chemo-sensitive tumors, it may be interesting to achieve a temporary embolization to avoid definitive destruction of the tissue. Temporary embolization would be possible using biodegradable microspheres. The aim of our work was to develop degradable microspheres having all requiredcharacteristics to be used as embolization material (well calibrated in size, biocompatible, rigide enough to resist blood pressure but elastic enough to remain intact during injection through catheter). To this purpose, we have developed hydrolysable hydrogel based microspheres by suspension polymerization. A wide range of microspheres was synthesized by varying the type of crosslinker and composition of the polymerization medium. In vitro test showed that the microspheres have suitable characteristics to pass through catheter. Degradation studies revealed a rapid diminution of G’ modulus and the pH of the supernatants, accompanied by an increase of swelling ratio due to the hydrolysis of the crosslinkings. Although microspheres were not totally degradable as expected (since a side reaction had created non degradable crosslinking during the polymerisation), characterisations showed promising results that the degradation did occur within a suitable time scale requirements for temporal embolization
Gers, Romain. "Analyse locale de l'hydrodynamique d'un broyeur à billes agité pour le traitement de dispersions solide-liquide." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT024H/document.
The stirred media mill is used to produce nanoparticles from dense suspensions. The purpose of our study is to analyse the influence of the hydrodynamics on the fragmentation process. The first part is devoted to the flow modelling in the mill for an equivalent fluid. The constitutive law is accounting for the properties of grinding beads and suspended particles. Velocity fields, obtained by direct numerical simulations, have permitted to analyse the collision characteristics and to determine the major mechanisms leading to fragmentation. By determining the impact velocities and collisional Reynolds we were able to set up an experiment modelling two approaching grinding beads. One bead is mobile while the other is fixed. The flow velocities in the fluid have been measured by PIV for a wide range of conditions. These velocity fields have been used to calculate particle trajectories within the gap between the two beads. This yields to estimate a capture efficiency for particles. We concluded that an increase of the particle diameter or an increase of the impact velocity increases the probability of capture. Additionally, trajectories of deposited particle at the surface of the fixed spheres show that the capture efficiency decreases when the Stokes number of the particle increases
Lafargue, Laurent. "Configuration mécanique d'accéléromètres électrostatiques pour le test en orbite du principe d'équivalence." Paris 6, 2002. http://www.theses.fr/2002PA066204.
Minker-Villemin, Caroline. "Préparation de suspensions aqueuses de vermiculite pour l'élaboration de films diélectriques /." [S.l.] : [s.n.], 1994. http://library.epfl.ch/theses/?nr=1249.
Hudson, Danya. "Investigation expérimentale et théorique du prototype du capteur inertiel pour la vérification du principe d’équivalence dans la mission spatiale MICROSCOPE." Paris 6, 2007. http://www.theses.fr/2007PA066448.
The MICROSCOPE mission is a space based test of the equivalence principle, to a precision of 10^-15. The test will be performed by a differential accelerometer in which two proof masses of different materials are held on the same trajectory by means of electrostatic forces. Because the instrument optimized for use in orbit can not function on ground, a series of development models are necessary. The first functional model, the prototype, is the subject of this thesis. The work begins with the development of equations for the capacitance between the proof mass and its control electrodes and the creation of a computer simulation required to define the mass control laws. The precision of the sensor integration is verified before beginning the experimentation which leads to the first complete levitation of a cylindrical proof mass. Measurements from the prototype, once in an optimal configuration, provide the first confirmation of the theoretical predictions of the sensor performance
Mascart, Monique. "Mise en suspension de poudres métalliques en vue de leur application par roll-coat analyse structurale des revêtements obtenus." Valenciennes, 1997. https://ged.uphf.fr/nuxeo/site/esupversions/d0ebab09-ade0-42e4-93b2-f4cf273386f9.
Malo-Estepa, Andrés. "Prise en compte de la variabilité des caractéristiques de suspension d'un bogie pour l'optimisation des opérations de maintenance." Thesis, Valenciennes, 2018. http://www.theses.fr/2018VALE0041.
The reduction of maintenance costs is a key stake for the competitivity of railway rolling stock manufacturers. The optimization of maintenance operations can be addressed by less, better-planned overhaul operations, through an increase of the life-cycle of some components. Among the most frequently checked suspension organs, rubber-to-metal elements have a key role on the bogie performance. The change on the mechanical properties of these elements are studied by accelerated ageing techniques, so as to represent their behaviour throughout their lifecycle. Several hyper-elastic laws, associated with the characterization of the rubber ageing, have been proposed in these works. These models have been used to simulate the behaviour of the real components. Hence, a set of tools describing the variability observed on the parts is proposed, allowing the design of a strategy for dynamics simulations considering several models of an already approved rolling stock model. The aim is to quantify the variability effect on the safety indexes demanded by standard norms. Finally, this study justifies the pertinence of a strategy aiming life-cycle extensions while ensuring the intrinsic safety levels required on railway rolling stock
Gelade, Pierre. "Stabilité et comportement rhéologique des coulis d'injection pour gaine de précontrainte." Paris 7, 2001. http://www.theses.fr/2001PA077198.
Marzougui, Donia. "Extension de la DEM aux granulaires immergés pour l'étude des suspensions denses." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI101.
A numerical model is used to simulate rheometer experiments at constant normal stress on dense suspensions of spheres. The complete model includes sphere-sphere contacts using a soft contact approach, short range hydrodynamic interactions defined by frame-invariant expressions of forces and torques in the lubrication approximation, and drag forces resulting from the poromechanical coupling computed with the DEM-PFV technique. Series of simulations in which some of the coupling terms are neglected, are also performed to evaluate the impact of some approximations which are classical inthe literature. It is found that the shear component of short range interactions plays a significant role in the magnitude of the bulk stress and it has a critical effect on the evolution of solid fraction. The effect of the poromechanical coupling is visible in the transient regime. The bulk shear stress is decomposed into contact stress and hydrodynamic stress terms whose dependency on the dimensionless shear rate Iv are examined. Both contributions are increasing functions of Iv. Statistics of microstructural variables are computed and highlight a complex interplay between contacts and hydrodynamic interactions. Finally, the dependance of the behavior of submarine avalanches function of the fluid viscosity η and of the angle θ of the material relative to the horizontal is studied. Results are in a good agreement with the phenomenological laws found experimentally
Rano, Simon. "Etude des propriétés de nanoparticules de LiCoO2 en suspension pour une application redox-flow microfluidique." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066197/document.
The aim of this work is to make a redox-flow battery that runs on lithium insertion material suspensions in order to increase the energy density of such systems. The use of microfluidic technics allows to solve the issues and limitations of ion exchange membrane by removing them. In the first part controlled size LiCoO2 nanoparticles are synthesized by hydrothermal route and dispersed into suspensions. The aggregation state of these suspensions are investigated using diffusion light scattering and transmission electronic cryoscopy. Rheological properties were also characterized for redox-flow use. The electronic transfer between a particle in suspension and the flow cell electrodes is crucial for their performances. This transfer is studied in the second part using the single event collision technic which consist of isolating individual aggregate electrochemical response at the surface of an ultramicroelectrode. This approach allows an extensive investigation of suspensions aggregates size, mobility and insertion reaction kinetic. Finally this works propose to replace the conventional ion exchange membrane by the mean of microfluidic technics. In co-laminar condition the fluid interface acts as a separation membrane to create a membrane-less redox-flow battery. The last part focuses on the fabrication of microfluidic cells and the behavior of suspensions in micro-channels
Bouyer, Étienne. "Étude de la préparation de poudres et de dépôts à partir de suspension par plasma inductif, le cas de l'hydroxyapatite phosphocalcique." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ35760.pdf.
Bouyer, Etienne. "Étude de la préparation de poudres et de dépôts à partir de suspension par plasma inductif le cas de l'hydroxyapatite phosphocalcique." Thèse, Université de Sherbrooke, 1997. http://savoirs.usherbrooke.ca/handle/11143/1673.
Bouyer, Etienne. "Étude de la préparation de poudres et de dépôts à partir de suspension par plasma inductif le cas de l'hydroxyapatite phosphocalcique." Sherbrooke : Université de Sherbrooke, 1997.
Shen, Yan. "Synthèse de poudres nanocomposites et dépôts de cathodes pour les piles à combustible à température moyenne." Mémoire, Université de Sherbrooke, 2011. http://savoirs.usherbrooke.ca/handle/11143/1620.