Добірка наукової літератури з теми "Porosité contrôlée"
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Статті в журналах з теми "Porosité contrôlée":
Baudu, Michel, Gilles Guibaud, David Raveau, and Pierre Lafrance. "Prévision de l'adsorption de molécules organiques en solution aqueuse en fonctions de quelques caractéristiques physico-chimiques de charbons actifs." Water Quality Research Journal 36, no. 4 (November 1, 2001): 631–57. http://dx.doi.org/10.2166/wqrj.2001.034.
Durand, David. "Porosité du contrôle des utilisateurs d’armes & ‘Taqiya’ made in France." Sécurité globale 11, no. 3 (2017): 171. http://dx.doi.org/10.3917/secug.173.0171.
Colin, F., Y. Noack, J. J. Trescases, and D. Nahon. "L'alteration lateritique debutante des pyroxenites de Jacuba, Niquelandia, Bresil." Clay Minerals 20, no. 1 (March 1985): 93–113. http://dx.doi.org/10.1180/claymin.1985.020.1.08.
Eyebiyi, Elieth. "Étudier l’État à partir de l’informalité. Répression et résistances autour du commerce informel de carburant1." Lien social et Politiques, no. 76 (July 18, 2016): 77–95. http://dx.doi.org/10.7202/1037066ar.
Дисертації з теми "Porosité contrôlée":
Lei, Yannick Ruani. "Matériaux composites électroactifs à porosité contrôlée." Montpellier 2, 2009. http://www.theses.fr/2009MON20074.
Among all systems for electrical storage, electrochemical devices are interesting because they turn chemical energy into electrical energy. Supercapacitor and Li-ion battery have high power density and good energy density, respectively. The topic of the present work is the preparation of composite electrode material MnO2/C for supercapacitor, SnO2/C for Li-ion battery and synthesis of porous SiC. This could be achieved starting by the synthesis of mesoporous carbon (900m2/g) following a hard template method. At first, the evaluation of electrochemical performances of composite electrode material for supercapacitor shows two different behaviours versus the ratio of MnO2. We could observe an optimal ratio for which capacitance was maximal (900F/g). Secondly, the volumic variations occurring while charge/discharge of SnO2/C electrode materials are contained by the carbon matrix. In spite of limited electrochemical performances for pure SnO2 electrode material, the cyclability of SnO2/C electrode materials is enhanced. At last, the synthesis of porous SiC can be achieved by the thermal reduction of SiO2/C composite using Mg as reducing agent. The as-prepared material is a replica of silica template
Boulvert, Jean. "Traitements acoustiques à porosité contrôlée pour atténuation optimale." Thesis, Le Mans, 2020. http://www.theses.fr/2020LEMA1033.
This thesis exploits some of the new possibilities offered by additive manufacturing to design and optimize treatments for sound attenuation consisting in porous materials. Additive manufacturing allows to control individually each pore of a material. The porous treatment design process is turned upside down: instead of searching through a catalogue of existing materials to solve a problem, it is possible to directly design the right material by adjusting its microstructure. This research is part of a plan to reduce aircraft engine noise but extends beyond the aeronautical field, both theoretically and in terms of possible applications. A predicting method of the acoustic behaviour of porous materials produced by additive manufacturing and taking into account the impact of manufacturing defects is first introduced. Porous materials with controlled graded properties are then studied. A method for optimizing microstructural or manufacturing parameters is developed. The ability of graded porous materials to attenuate frequencies too low to be attenuated by non-graded materials is then proven and the optimal gradient for broadband attenuation is defined. The impact of the wall thickness of the pores along with the impact of transverse propagation inside porous materials is studied. Finally, a metaporous treatment allowing broadband and sub-wavelength absorption is developed. The results of this research can be applied to create porous treatments with a high noise attenuation. The analytical and numerical models used in this research are based on the hypothesis of porous materials acoustically behaving as equivalent fluids. The results are physically analyzed and experimentally validated through impedance tube testing of specimens produced by additive manufacturing
Benamor, Taissire. "Synthèse et caractérisation de silices mésoporeuses hydrophobes à porosité contrôlée." Phd thesis, Université de Haute Alsace - Mulhouse, 2011. http://tel.archives-ouvertes.fr/tel-00705930.
Karaki, Mariam. "Matériaux à porosité contrôlée sulfonés : Synthèse, Caractérisation, Etude des propriétés catalytiques." Phd thesis, Université de Haute Alsace - Mulhouse, 2013. http://tel.archives-ouvertes.fr/tel-01064374.
Henon, Joseph. "Elaboration de matériaux poreux géopolymères à porosité multi-échelle et contrôlée." Limoges, 2012. http://aurore.unilim.fr/theses/nxfile/default/2e0cd75e-4baa-4db6-980a-67278d007105/blobholder:0/2012LIMO4019.pdf.
This work is focused on the preparation, the characterization, and the control of the porosity in geopolymer foams, synthesized from the mixing of metakaolin, a alkali silicate solution, alkali hydroxide, and silica fume as the pore forming agent. This mixture results in a foam in which hydrogen gas is produced continuously in an evolutive viscous gel. The control of porosity, in consideration of the very high value of pH, requires the establishment of an equilibrium between the kinetics of polycondensation reactions (hardening) and the kinetics of gassing. The influence of different parameters is studied through the characterization of the obtained porous network. The thermal conductivity of the homogeneous samples is measured with a fluxmeter and also with a hot wire method. The values obtained are then discussed in relation to the microstructure and relevant analytical models of the literature. An inverse numerical approach is used to find the thermal conductivity value of the skeleton of the foam λs. In fact, it is difficult to prepare a material with a low pore volume fraction from the same composition. A finite element calculation, coupled with a homogenization method, is applied on Representative Volume Elements constructed in relation with the experimental data. The value of λs is then calculated between 0. 98 and 1. 12 W. M-1. K-1. The foams have pore volume fractions values between 65 and 85% corresponding to thermal conductivity values between 0. 12 and 0. 35 W. M-1. K-1, yielding a good material for thermal insulation
Morin, Camille. "Préparation d'alumine à porosité contrôlée : étude de l'interaction de la boehmite dans des solvants et des propriétés fonctionnelles des matériaux résultants." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066702/document.
Textural properties of catalytic supports are closely related to the organization of boehmite crystallites (AlOOH, nH2O) during the synthesis and the shaping. The modification of this organization by mixing the boehmite with alcohols leads to an increase of the porosity which is very interesting for catalysis processes sensitive to diffusional limitations. A novel way of support preparation obtained by dispersing boehmite in mixed protic polar solvents allows highlighting a control of the porosity depending on the solvents ratio. The kinetic of aggregation, and hence the particles organization, is influenced by the solvent nature. The tuning of the steric effect and the affinity of the solvent for the boehmite surface allows controlling the solvation layer thickness. Consequently of this particular microstructure in dispersion, the porosity can be tuned on a wide range, while keeping a constant specific surface area. The impact on the functional properties of the support, like the mechanical and the catalytic properties, are estimated. A two-nested scales micromechanical approach was carried out and leads to elastic modulus close to the experimental one. Hydrodemetallization activity is greatly enhanced with the porosity, while preserving a high hydrodesulfurization activity. This study is promising in order to predict the properties of the final support from the control of the dispersion microstructure
Petlitckaia, Svetlana. "Synthèse de mousses géopolymères à porosité contrôlée : application à la décontamination nucléaire." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS029/document.
This study aims to develop geopolymer foams with connected macroporosity for the treatment of radioactive liquid wastes. The first part of this work was to synthesize geopolymer monoliths by direct foaming using hydrogen peroxide (H2O2) as blowing agent. It decomposes in a basic medium to produce oxygen and thus produces the geopolymer foam by nucleation and growth of oxygen bubbles until exhaustion of the source term and/or setting of the material. To stabilize the generated gas bubbles, the addition of a surfactant is necessary to limit coalescence phenomena. The influence of the H2O2 concentration, the chemical nature of the surfactant and the viscosity of the paste on the kinetics of production and on the final properties of the foam thus produced, was studied. The results conventionally show that a high initial concentration of H2O2 produces high porous foams, with high pore sizes and less mechanical properties. On the other hand, the choice of the chemical nature of the surfactant has a very strong influence on the one hand on the rheology of the geopolymer paste and on the other hand on the properties of the porous network. Indeed, by an appropriate choice of the surfactant, it is possible to obtain geopolymer foams with closed or open macroporosity, with pore size distributions more or less spread and with good mechanical properties. At the end of this first step, a well-connected geopolymer monolith was functionalized by precipitation of copper hexacyanoferrate particles known to be very selective with respect to cesium. The tests were performed in batch mode in different media (pure water, fresh water and fresh water loaded with competitor cations in high concentration). The kinetic and adsorption isotherms of cesium were determined over a wide range of cesium concentration (from trace to 1000 ppm) and the functionalized geopolymer foam showed remarkable performance for selective entrapment of cesium as compared to an unfunctionalized foam. Indeed, the tests in radioactive medium (trace of cesium in fresh water) have shown that the value of the distribution coefficient (Kd) for the functionalized foam is around 5.5 105 ml.g-1
Ballestero, Anthony. "Elaboration de matériaux à base de carbure de silicium et à porosité contrôlée." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT192/document.
Preceramic polymers have been proposed in the late fifty’s as non-oxide silicon based ceramic precursors generally called PDCs for “Polymer Derived Ceramics”. Compared to traditional synthesis ways, the PDCs route can offer many advantages in terms of compositions, structures and textures of ceramics. Due to its intrinsic properties (thermal, chemical and mechanical resistance, semi-conductor behavior,...), silicon carbide (SiC) and their derivatives with nitrogen (silicon carbonitride, SiCN) can be considered as one of the best materials for the next generation of ceramic based membranes, in particular in the hydrogen production processes (from CO2, CH4 or through the water gas shift reaction for example). By investigating the PDCs route, a hydrophobic and amorphous SiC material suitable for hydrogen separation process exhibiting good permeability/selectivity ratio, high thermal mechanical and chemical resistance coupled with a good stability under wet atmosphere up to 500°C can be proposed. However, the use of preceramic polymrers induces an important dimensional modification during the pyrolysis allowing the conversion from polymer to ceramic. Residual stresses caused by the volume shrinkage leads to the formation of cracks or even collapses of the structure of shaped preceramic polymers. This study is focused on the elaboration of SiC based macroporous substrates or microcellular foams, mesoporous and microporous coatings in the aim to propose a SiC based material showing a hierarchized porosity dedicated to gaseous separation applications. The AllylHydridoPolycarbosilane (AHPCS) is used as SiC precursor. After the chapters I and II, respectively dedicated to a literature review and the materials and methods used, two strategies are enforced in the chapters III and IV to generate these materials with a better control of the polymer dimensional change. In the first strategy (chapter III), passive (nanodiamonds) and active (boron particles) fillers are introduced in the AHPCS to generate some formulations with different fillers proportions and opposing to the volume shrinkage of the polymer during the pyrolysis and create composite materials. In the second strategy (chapter IV), a single molecular source approach consisting of the introduction of boron at the molecular state in the AHPCS is proposed. This introduction of boron leads to increase the ceramic yield and to reduce the mass loss of the modified AHPCS during the pyrolysis. In the chapters III and IV, monolithic dense structures are developed to better understand the dimensional change occurring during the pyrolysis. Synthetized and selected formulations and polymers will serve as precursors for macroporous, mesoporous and microporous materials in the chapter V
Nguyen, Thi Hoa. "Films minces de copolymères à blocs pour la réalisation de gabarits à porosité contrôlée." Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00821029.
Coupé, Aurélie. "Synthèse et caractérisation de particules aluminosilicates à porosité contrôlée par atomisation : application à la catalyse." Paris 6, 2005. http://www.theses.fr/2005PA066491.