Tesi sul tema "Séparation moléculaire"
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Moreno, Martinez Diego. "Etude par dynamique moléculaire de la séparation de l'uranium (VI) sur support solide". Electronic Thesis or Diss., Montpellier, Ecole nationale supérieure de chimie, 2022. http://www.theses.fr/2022ENCM0018.
The uranium extraction plays an essential role in the nuclear fuel cycle. The extraction using mesoporous silica solid supports represents a promising alternative to the liquid-liquid extraction processes. In fact, the compactness of these solid supports, the facility of implementation associated to the reduction of organic effluents give to this system great competitive advantage. This kind of systems has already been studied experimentally within the framework of two PhD students in the CEA (Atomic Energy Commission). Thus, the objective of this research, centered on theoretical chemistry studies (especially by molecular dynamics), is to rationalize the behaviors that have been experimentally observed and to provide comprehension elements about the involved mechanisms. In order to do this, the uranium (VI) coordination at the interface within the solid phase and the aqueous phase, the influence of diverse structural parameters of the solid support, and the chemical conditions of the uranium speciation will be studied
Piras, Patrick. "Développement et exploitation d'une base de données moléculaire pour la séparation d'énantiomères par chromatographie liquide". Aix-Marseille 3, 1994. http://www.theses.fr/1994AIX30097.
Boudard, Sébastien. "Séparation de phases contrôlée dans des couches phospholipidiques supportées : vers des empreintes moléculaires". Strasbourg 1, 2007. http://www.theses.fr/2007STR13137.
The aim of this work was to investigate if supported lipid bilayers can be used as two-dimensional matrices for large templates (proteins, DNA, etc. ). This idea requires a liquid bilayer composed of at least two compounds to allow a phase separation in contact with a suitable template. The composition and the physicochemical properties permit to control the combinatorial recognition of the template and the freezing of the imprints by temperature. The features of the lipid supports assure the reversibility of the imprinting process based on the transition of a lipid mixture from the fluid state to the gel state and vice versa. We have carried out detailed physicochemical characterisations of several such systems with a phase transition temperature close to the ambient. This has led to new conclusions concerning the mechanism of bilayer formation. In addition we have demonstrated that the mobility of the lipids strongly depends on the lateral pressure of the upper leaflet of the bilayer, confirming existing hypothesis. We have also been able to demonstrate by various techniques (QCM-D, fluorescence microscopy and AFM) that the adsorbing template leads to a 2D-phase separation (patterning). However this remains a difficulty to prove that this structuration leads to reversible recognition events. The present work has been successful in narrowing down considerably the parameter space for future experiments. Thus, the validation of our approach will require the optimization of the lipid system and the use of new investigation techniques
Bahhitti, Meryem. "Extraction, séparation et identification des principes tinctoriaux du pastel (Isatis Tinctoria L. )". Toulouse, INPT, 1997. http://www.theses.fr/1997INPT009G.
Morel, Lydie. "Vulnérabilité à la dépendance : étude comportementale, biochimique et moléculaire du modèle de séparation maternelle chez le rat". Paris 5, 2009. http://www.theses.fr/2009PA05P629.
Neurobiological characteristics of an individual depend, on one hand on its genes and on the other one on his environment. Consequently, environmental factors (chronic stress, psychoactives substances) can produce long term effects on the neurophysiology and hence on neuropathologies such as depression or addiction. In order to analyze molecular mechanisms leading to vulnerability to drug dependence we have used a maternal deprivation model. In this model, maternal deprivation results into i) an increased sensitivity to morphine reward and ii) a decreased expression of preproenkephaline (PPE) mRNA and the peptid Met-enkephalin in striatum. In this model we investigated the consequences of cannabis exposure during adolescence on the vulnerability to opiates dependence in adults rats. THC treatment of young rats suppressed the hypersensitivity of mother deprived (D) rats whereas it sensitized non deprived animals (AFR). These behavioral modifications are paralleled respectively by an increase or a decrease of PPE mRNA levels in he striatum of D rats. Then, a lentiviral vector was designed for exogenous modulation of PPE expression in the rat striatum. This tool, will be used to enhance PPE expression and Met-enkephalin in D rats and observe the behavioral consequences on opiate dependence. Then, we tried to identify the mechanisms involved in long term regulation of PPE expression after maternal deprivation. We focused on epigenetic modifications of its promotor. We observed an hypermethylation and MeCP2 binding on the promotor region of PPE. These results suggest that epigenetic regulation occur after maternal deprivation. Thus providing possible therapeutic target for vulnerability to drug dependence
Palaprat, Guillaume. "Polysiloxanes mésomorphes à empreinte moléculaire chirale : synthèse des squelettes et des substituants : application à la séparation d'énantiomères". Paris 6, 2006. http://www.theses.fr/2006PA066074.
Dong, Chen. "Modification de systèmes époxy avec des élastomères solubles et réactifs : Étude de la séparation de phase induite par la réaction chimique". Lyon, INSA, 1992. http://www.theses.fr/1992ISAL0051.
The reaction induced phase separation in an epoxy s ystem modified by a soluble and reactive rubber was observed i n-situ with several methods. By light scattering and light transmission, the formation of microsize particulate morphology keeps unchanged there after. By SAXS, the beginning of phase separation was detected much earlier than the cloud point After the particulate morphology formation, further phase separation takes place only inside the formed particules resulting in a heterooeneous sturcture. Development of such a strcture can be followed by SAKX and observed by TEM in the final materials. A theoretical model based on Flory-Huggings equation was used to scheme the phase separation process. Influences of the molecular weight and en groups of rubber on the miscibility, the phase separation, the particulate morphology and the sub-particle structure were examined
Nedez, Christophe. "Chimie organométallique de surface de l'étain, du germanium et du zirconium : application à la séparation moléculaire sur zéolithes". Lyon 1, 1992. http://www.theses.fr/1992LYO10197.
Pandiyan, Sudharsan. "Modélisation moléculaire de la perméabilité du CO2 dans les membranes polymères". Chambéry, 2009. http://www.theses.fr/2009CHAMS045.
Carbon dioxide (CO2) separation studies have become a major interest for researchers in the 21st century. In the case of polymer matrices, it is important to examine the relationships between the permeation properties of CO2 and the structural and dynamical features of the polymers. We have selected three fluorinated polyimides (6FDA-6FpDA, 6FDA-6FmDA and 6FDA-DAM) and used molecular dynamics (MD) simulations to provide a detailed picture of their CO2 permeation properties at the molecular level. Atomistic models of the three fluorinated polyimides were generated using the well-established hybrid Pivot Monte Carlo (PMC)-MD single-chain sampling technique, and were subsequently simulated using MD on its own. All the models were found to compare well with experimentally-derived properties such as densities, fractional free volumes, d-spacing parameters, solubility parameters, energies and X-ray data. Structures and void-space distributions in the pure matrices were also analysed. A realistic stepwise addition of CO2 was carried out in the pure polymer matrices and an iterative procedure was used to calculate the CO2 model sorption isotherms. In addition, the volume swelling induced by CO2 sorption and the immediate effect of exposure to high concentrations of CO2 on the desorption isotherms were also studied. The void spaces, potential energies and the formation of CO2 clusters were characterized and compared with experimental characterizations. The diffusivity of CO2 as a function of CO2 concentration within the polymer matrices was analysed, and the factors affecting mobility were reported in detail
Vigneau, Olivier. "Synthèse et évaluation de polymères imprimés pour la séparation d'éléments f : application en chromatographie liquide". Lyon 1, 2002. http://www.theses.fr/2002LYO10012.
Garcia, Régis. "Contribution à la séparation actinides-lanthanides : utilisation de matériaux ionosélectifs synthétisés par empreinte ionique". Lyon 1, 1998. http://www.theses.fr/1998LYO10098.
Turgeon, Pierre-Alexandre. "Étude de la séparation et des mécanismes de conversion des isomères de spins de l'eau". Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/11079.
Milon, Nicolas. "Technologie µLAS pour l'analyse et la purification d'ADN de haut poids moléculaire". Thesis, Toulouse, INSA, 2019. http://www.theses.fr/2019ISAT0005.
In forty years only, DNA sequencing technologies triggered a revolution in biological analysis with the beginning of the genomic era. Nevertheless, this booming technological field is still hampered by unmet technological needs for DNA sample preparation and quality control. The most recent third generation sequencing technologies require very long DNA fragments of more than 50,000 base pairs, the manipulation and characterization of which remains a technological challenge. In the prospect of accelerating and improving state of the art protocols for sample preparation, we developed an instrument, based on the µLAS technology that allows the concentration and separation of high molecular weight DNA fragments with high sensitivity. With this technology, we developed a method for the isolation and sequencing of target genomic regions in complex genomes. We report the isolation, the sequencing and the assembly of a locus of 31.5 kb extracted from the genome of the plant Medicago Truncatula. We finally developed a prototype for high molecular weight DNA purification in complex samples, which is based on a size-accordable DNA valve for the size selection in the range 200 – 50,000 bp. In this manuscript we highlighted the relevance of µLAS technology for the analysis and purification of high molecular weight DNA
Cevallos, Ramiro. "Micrométastases dans le cancer du sein : de l'image scintigraphique à la détection moléculaire". Compiègne, 1999. http://www.theses.fr/1999COMP1241.
Pinel, Eliette. "Relations entre architecture à différentes échelles de membranes copolyimides et propriétés physiques : application à la séparation des gaz". Chambéry, 2001. http://www.theses.fr/2001CHAMS021.
Jeffroy, Marie. "Simulation moléculaire des propriétés des zéolithes cationiques : Propriétés thermodynamiques et propriétés structurales". Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00517043.
Foucaud, Yann. "Récupération du tungstène à partir d'un skarn à faible contraste de séparation : apport de la modélisation moléculaire dans la flottation des minéraux calciques". Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0149.
Nowadays, skarns represent more than 40% of the global resources in tungsten, which has been classified as a critical raw material in the European Union. In particular, the Tabuaço deposit constitutes an archetype of tungsten skarns and contains high amounts of calcium minerals, including fluorite, apatite, and vesuvianite, in close association with scheelite (CaWO4). According to their similar surface properties, the separation of these minerals by flotation with fatty acids is significantly difficult and, therefore, remains a scientific challenge. In this study, which has been conducted within the framework of the FAME H2020 European project, an economic, environment friendly, and transferable process has been developed for the Tabuaço ore to demonstrate the feasibility of the tungsten skarns processing. In the froth flotation process, the Na2CO3/Na2SiO3 system has exhibited the best efficiency in terms of gangue minerals depression due to considerable synergistic effects that have been subsequently described by statistical, spectroscopic, and atomistic methods. Meanwhile, the influence of the ratios between different carboxylic acids in the collector formulations (Tall Oil Fatty Acids) has been assessed to improve the flotation selectivity. In addition, the enhanced gravity separation (Falcon centrifuge concentrator) has been investigated, optimised, and combined with the flotation to produce a marketable scheelite concentrate assaying 63% WO3 with 59% recovery. Besides, to gain understanding in the molecular mechanisms involved in the flotation process, the fluorite and scheelite interfaces have been modelled using the density functional theory. This study has allowed to characterise the hydration state of these minerals, which display different affinities for water molecules. Furthermore, the adsorption of fatty acids on fluorite has been studied to unravel the adsorption mechanisms of these molecules on calcium minerals, confirmed by experimental investigations
Douarche, Carine. "Étude de l'adsorption de l'ADN simple brin et double brin aux interfaces". Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-183.pdf.
Guo, Juncheng. "Molecular Simulation Study of Transport and Separation of Gas through Nanoporous Graphene Membranes". Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3029.
Nanoporous graphene membranes are gaining attention in the field of separation processes. Regarding gas separation, perm-selective membranes technology consumes less energy than other conventional technologies. Due to nanoporous graphene’s atomic thickness, controllable pore size in the range of molecular diameters, mechanical and chemical stability, it is considered as one of the most favorable membrane material for industrial gas separation applications. For instance, in the context of natural gas production and air separation, the separation of CH4/CO2, N2/O2 mixtures would greatly benefit from this kind of new materials. With the rapid development in graphene fabrication technology, breakthroughs in nanoporous graphene membranes are expected in the next few years and quite sufficient data can be found in publications. However,there is no accurate theory that can predict gas permeation and separation factor quantitively.In this work, we show that gas permeation through single-layer nanoporous graphene membranes can be divided into three regimes: molecular sieving, crossover regime and effusion. We propose a theoretical framework to explain the mechanisms and predict the diffusive transport coefficient. In our framework, the transport coefficient is related to the parameters which can be computed from the potential of mean force (PMF) between permeating gas molecules and the membrane atoms. By means of Equilibrium (EMD) and Non Equilibrium (NEMD) molecular dynamics simulations, we explore the permeation of pure compounds through nanoporous graphene membranes exhibiting differentpore sizes and geometry. We also investigate the effect of thermodynamic conditions (pressure and temperature) on the transport coefficient. Simulated transport coefficients are in good agreement with the predictions of our theory over the whole range of permeation regimes. Furthermore, based on the knowledge acquired on the permeation of pure compounds, we define the concept of selectivity. By comparing the results of molecular simulations performed with gas mixtures, we show in which cases the results weobtained for pure compounds, and consequently our theoretical framework, allow us to predict the selectivity of mixtures
Venet, Saphir. "Stockage du CO2 et séparation CO2/CH4 par des matériaux de silice à porosité et fonctionnalité contrôlées : étude expérimentale et modélisation de dynamique moléculaire". Thesis, Pau, 2018. http://www.theses.fr/2018PAUU3027/document.
This work aims to evaluate the performance of silica-based materials and to rationalize their synthesis according to their desired adsorption properties (capacity and/or selectivity) by combining experimental approaches and the management of the molecular animal. These materials are ideally suited for CO2 adsorption capacity but also CO2/ CH4 selectivity. The different stages of this work were:- the synthesis and functionalization of the silica materials,- their textural and chemical characterization,- the determination of CO2 adsorption capacities, of their CO2/ CH4 selectivity.- the characterizations by various spectroscopic and microscopic techniques of tests to try to locate the adsorption of CO2 and to measure its mobility,- microscopic identification by the factor of physic-Factors influence the preferential adsorption of CO2 and its diffusivity in the role of hydrophilic / hydrophobic character in silica by functional.These objectives required the preparation of high specific surface materials through a simple sol-gel process. These materials have been modified in order to obtain a degree of functionalization with -CH3 groups sufficient to modify the hydrophilic nature of the material while maintaining a sufficient specific surface area. The influence of pore size was also probed.The adsorption capacities of the gases under pressure were carried out for pure gases but also on CO2/ CH4 mixtures in different proportions. The CH4/ CO2 selectivity, often estimated from the pure body isotherms and / or the IAST method, was in this case determined from the direct measurement of the isotherms of the gas mixtures. It has become apparent that water plays a crucial role in adsorption capacity and selectivity. This parameter is one of those studied through molecular dynamics simulations. The influence of the introduction of hydrophobic groups has also been explored.The results obtained by molecular dynamics are on the whole in good agreement with the experimental data. These two parallel experience / theory approaches have highlighted the selectivity of one of the materials for applications where the gaseous effluent is little loaded with CO2
Gannaz, Benoît. "Spéciations moléculaire et supramoléculaire de systèmes d'extraction liquide-liquide à base de malonamide et/ou d'acides dialkylphosphoriques pour la séparation An(III)/Ln(III)". Paris 11, 2006. http://www.theses.fr/2006PA112061.
The solvent extraction system used in the diamex-sanex process, developed for the actinide(iii)/lanthanide(iii) separation, is based on the use of mixtures of the malonamide dmdohema and a dialkylphosphoric acid (hdehp or hdhp), in hydrogenated tetrapropylene. The complexity of these systems urges on a novel approach to improve the conventional methods (thermodynamics, solvent extraction) which hardly explain the macroscopic behaviors observed (3rd phase, over-stoichiometry). This approach combines studies on both supramolecular (vpo, sans, saxs) and molecular (liquid-liquid extraction, esi-ms, ir, exafs) speciations of single extractant systems (dmdohema or hdhp in n-dodecane) and their mixture. In spite of safety constraints due to the handling of radiomaterial, they were used in the studies as much as possible, like for saxs measurements on americium-containing samples, a worldwide first-time. In each of the investigated systems, actinides(iii) and lanthanides(iii) are extracted to the organic phase in polar cores of reversed micelles, the inner and outer-sphere compositions of which are proposed. Thus, the 4f and 5f cations are extracted by reversed micelles such as [(dmdohema)2m(no3)3]inn[(dmdohema)x(hno3)z(h2o)w]out and m(dhp)3(hdhp)y-3(h2o)w with y = 3 to 6, for the single extractant systems. In the case of the two extractants system, the less concentrated one acts like a co-surfactant regarding the mixed aggregate formation [(dmdohema)2m(no3)3-v(dhp)v]inn [(dmdohema)x(hdhp)y(hno3)z(h2o)w]out
Chouikhi, Najib. "Production de biométhane à partir de biogaz par technologie de séparation par adsorption PSA : optimisation numérique par approche multi-échelle". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST043.
As global interest in renewable energy intensifies, biogas production continues to grow as a clean, renewable source. Pressure Swing Adsorption (PSA) is considered as one of the most interesting technologies for the valorization of biogas into biomethane. The great flexibility of the PSA process is linked in some way to its complexity with several design and operating parameters which control the performance of the separation unit. The identification of these parameters by an experimental approach is practically impossible. A numerical study stage is essential for sizing the unit, designing the pressure cycle and identifying the optimal operating conditions before any experimental test.The general objective of the thesis was focused on the development of simulation tools for a biomethane purification process using PSA technology.In a first stage, a simulation based on one-dimensional non-isothermal dynamic model, where the intragranular mass transfer kinetics was modelled using a double driving force (bi-LDF) approximation, was implemented. A carbon molecular sieve (CMS-3K) was selected. This adsorbent ensures a high kinetic selectivity of carbon dioxide with respect to methane (CH4). The optimized cycle, composed of five columns and fifteen steps including three equalization steps and a purge gas recycling allowed a CH4 recovery of 92% with a moderate specific energy consumption of 0.35 kWh/Nm3 , at the same time respecting the grid injection specifications (97% CH4 purity ). The performance obtained is thus compatible with industrial operation.The development of a multidimensional (3D) and multi-scale (column/grain/crystal) numerical model would serve to evaluate the limits of the assumptions and correlations used in usual simulators. The first step consists in simulating the gas flow in an adsorbent bed having a reaslistic stacking.. Thus, an inert packed bed was numerically generated by DEM calculation (discrete element modeling) for a column of laboratory size. The use of OpenFOAM (CFD software) allowed to calculate the three-dimensional tracer gas flow in the column. In parallel an experimental study of the breakthrough curves was carried out using a bed having the same dimensions and characteristics. The breakthrough times and the dispersion-diffusion coefficients calculated and measured were similar. However the simulation showed some divergences in the concentration of the tracer locally in the column, due to difficulties in meshing. The next step will consist in taking into account grain-fluid interactions by considering porous adsorbent grains
Wakkel, Manel. "Contribution à l'étude de la séparation des protéines par chromatographie d'échange d'ions en milieu complexe. Effet du poids moléculaire sur l'équilibre et la cinétique de rétention". Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0023/document.
Bioseparations from crude media, vegetable or biological, is a large and complex subject. Future industrial issues depend ontheir understanding and development, namely for biotechnological processes as downstream processes represent up to 80 %of their total cost. This work hopes to contribute to these general questions. It is justified by previous results obtained in thelaboratory showing that it is possible to recover a high molecular weight (HMW) protein from a complex vegetal juice in justone chromatographic operation. Hypotheses have been formulated, to which this work tries to answer: what mechanism couldexplain this behaviour? Is-there a specific location inside particles for the uptake of such protein, facilitating the recoveryduring elution step? Our objective has been to progress on the knowledge of fundamental questions concerning ion-exchangechromatography and their applications for proteins recovery from complex media. The effect of the other proteins in solutionhas been analysed, specifically in the situation where both proteins have a very different molecular weight, as in the previouscited work. Theoretical and experimental approaches, at various scales, have been applied or developed on real or syntheticsystems in order to answer some of these questions. At the process scale, a statistical method for data analysis (PrincipalComponent Analysis or PCA) has been applied. The complete interpretation of its results remains very hard. At thelaboratory scale, equilibrium and kinetics of ion exchange have been studied for synthetic solutions of two proteins: bovineserum albumin (BSA) (as reference protein widely studied), and ferritin (iron storage protein) having similar isoelectric pointas BSA but with higher molecular weight. Classical models for ion-exchange kinetics can explain the experimental results,even for HMW proteins. Mass transfer fluxes seem to be coupled for both proteins, even if they have usually very differentdiffusivities. The interpretation of equilibrium results is much more difficult. Equilibrium uptake of ferritin is not, or lightly,influenced by salt concentration or BSA content. Nevertheless, the presence of ferritin in the medium affects strongly BSAequilibrium uptake (however more favourable). Among the phenomena suggested in the literature, the Vroman effect hasbeen researched but it does not take place under the experimental conditions applied. Simulation of multi-componentisotherms has not been possible by classical models (such as multi-component Langmuir isotherm), while protein isothermsin single solution are standard. Besides, a partial blockage of the resin pores by ferritin is possible, preventing BSA diffusion.Therefore, a methodology has been developed at the microscopic scale, with the aim to observe concentration profiles forrepresentatives elements (P, Fe, Cl …) inside particles. The method, well developed, does not allow to conclude for themoment, because the probes used were not sensible enough
Danjou, Pierre-Édouard. "Élaboration de nouveaux fluoroionophores et de supports chélatants en vue de l'amélioration de la caractérisation du fer dans les particules atmosphériques". Thesis, Littoral, 2012. http://www.theses.fr/2012DUNK0446/document.
The aim of this work is to provide new molecular tools for the physico-chemical characterization of atmospheric particles in order to establish a link between their properties and their pulmonary toxicity. We particularly investigate the detection and quantification of iron, a major element in industrial particle of Dunkirk city, France. So, in a first hand, we have developed the efficient synthesis of new fluorescents chemosensors by ultrasounds and microwave irradiation. Then the study of these compounds was undertaken and has revealed a highly selective sensor of ferric iron in non-buffered aqueous solution in presence of other metallic cation. In the other hand, we have synthesized new solid supports which beard supramolecular chelatant or bio-inspired entities in order to separate iron traces from complex aqueous matrix
Coutte, François. "Production sélective de lipopeptides par Bacillus subtilis en bioréacteur à membrane : du génie moléculaire au génie des procédés". Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10115/document.
Bacillus subtilis produces up to three families of lipopeptides through a non-ribosomal mechanism, i.e., iturins, surfactins and fengycins or plipastatins. These molecules show a broad range of biological properties.Their biosynthesis is most often subject to complex regulation. In addition, the surface properties of these molecules make the production of the lipopeptide in an aerated bioreactor difficult because of the foaming, rendering difficult their large-scale production. This work was based on two approaches to optimize the production of the lipopeptide. On the one hand, an innovative process based on the technology of membrane bioreactor was developed for the production of lipopeptide to circumvant the massive foaming problem. For the first time, different bubbleless bioreactors were used for lipopeptide production by B. subtilis using hollow fiber membranes as air-liquid contactor. The performance of this bubbleless bioreactor enabled us to conduct a study of the lipopeptide production in a bubbleless bioreactor coupled with a continuous lipopeptide membrane extraction. On the other hand, a genetic optimization of the production of surfactin was undertaken to release its synthesis from a complex regulation and to obtain a single surfactin producer strain derived from B. subtilis 168, named BBG131. The different mutant strains obtained in this genetic optimisation process allow us to demonstrate some synergistic or antagonistic effect of surfactin and fengycin co-production on biological properties of Bacillus subtilis. Furthermore, the use of BBG131 in the integrated process previously developed led to the production, extraction and purification of several tens of grams of surfactin, pointing out the feasibility of this integrated process at the industrial scale
Ducouret-Cérèze, Annie. "Etude Mössbauer de l'ion Fe2+ dans les structures quadratiques K2FeF4 et Ba2FeF6, interprétée dans un modèle vibronique de complexe moléculaire". Le Mans, 1987. http://www.theses.fr/1987LEMA1032.
Kafrouni, Wassim. "Membranes a-SiCxNy:H déposées par CVD-plasma, tamis moléculaire pour la perméation de l'hélium". Phd thesis, Montpellier 2, 2009. http://www.theses.fr/2009MON20062.
This thesis was conducted to develop a new membrane material non-oxide silicon by PECVD used a molecular sieves mechanism for small gas permeation with a good resistance to water vapor. A-SiCxNy:H thin films were deposited in a capacitive reactor, using HMDSN as precursor, NH3 as dilution gas and argon as feed gas. We have varied the ammonia dilution and the plasma power to obtained different materials compositions, ranged from plasma polymers rich in carbon, to inorganic materials rich in nitrogen. The membranes were deposited on three kind of substrate: silicon wafer for microstructural characterization (XPS, EDX, FTIR, ellipsometry, contact angle, SEM), on piezoelectrique Quartz for sorption test (QCM) and on mesoporous alumina gamma for permeation test with He and N2. He permeance tests based on the transmembrane pressure at 25 C show that we are in a Knudsen diffusion mechanism with little effect of viscous mechanism, which reveals the presence of a very little amount of defects in the layer. The permeation test carried up to 150C on a series of membranes obtained under different plasma conditions that the permeance of He is activated by temperature, have shown that best performance are obtained for definite plasma conditions that have been optimized (plasma power and NH3 dilution). The transport mechanism of He in these membranes are thermally activated, the permeance of He increases with temperature
Kafrouni, Wassim. "Membranes a-SiCxNy:H déposées par CVD-plasma. Tamis moléculaire pour la perméation de l'hélium". Phd thesis, Montpellier 2, 2009. http://tel.archives-ouvertes.fr/tel-00466225.
Martinez, Triana Alvaro. "Transmembrane distillation for recovery of industrial aqueous effluents". Electronic Thesis or Diss., Université de Lorraine, 2023. https://docnum.univ-lorraine.fr/ulprive/DDOC_T_2023_0140_MARTINEZ_TRIANA.pdf.
The major subject of this research is the conceptual study of a transmembrane distillation process for the recovery of industrial effluents. The scientific issues studied in this work are covered by advanced separation processes: Materials: dense or porous polymers, experimental quantification at laboratory scale of the mass transfer mechanism, modelling of mass and heat coupled transfers, process simulation and optimization. In this thesis, the technological issues are addressed by a process simulation approach. A numerical unit operation brick for membrane technology simuation is proposed. It considers the physical and chemical phenomena at three levels: material, module (geometry, flow patterns) and process (operating conditions). The generic mathematical model presented in this work is adapted to three systems of industrial interest: water desalination (non-volatile component), boron-containing effluent treatment (component less volatile than water) and ammonia recovery (component more volatile than water). The adaptation of the mathematical model is based on experimental data found in the literature and complemented by experiments performed on laboratory-scale equipment. These experiments target the comprehension of the two main phenomena necessary for the calculation of the process selectivity: the modelling of the liquid-vapour equilibrium and the evaluation of the transfer coefficients for each component at the material level. This dedicated code, modified with the experimental results, is then integrated into a process simulation software, allowing architecture optimization, process synthesis and optimization. Industrial issues are evaluated by comparing traditionally deployed technologies (thermal-based technologies) with membrane technologies based on the evaluation of energy and production performances. Finally, the results allow the identification of the transmembrane distillation potential for the selective separation of components as alternative processes to existing technologies
Ziyyat, Ahmed. "Séparation de spermatides rondes par cytométrie en flux et expression génique durant le développement préimplantatoire après microinjection de la spermatide dans l'ovocyte de souris". Paris 11, 2000. http://www.theses.fr/2000PA11T062.
Bidault, Xavier. "Etude par modélisation des nanoparticules formées par séparation de phase dans les verres dopés terres rares". Thesis, Angers, 2015. http://www.theses.fr/2015ANGE0021/document.
Optical fibers with tailored spectral response are doped with luminescent ions, rare-earth ions (re), embedded in nanoparticles (np) formed in situ in silica glass through a phase separation process. This engineering requires to understand the relation between the np composition and the re environment. In molecular dynamics, the existing interatomic potentials fail to reproduce the phase separation as experimentally observed. The system xmgo-(1-x)sio2 exhibits a domain inside of which two mixed phases coexist, mg-rich either si-rich. Such a phase separation can only be modeled by an interatomic potential that takes into account bond ionicity, and the transferability isEnabled here by the adaptation of oxygen charges according to the local environment. This adaptive model allows for the 1st time to track the formation of amorphous np of few nanometers. Mixed and mg-rich, they separate from a si-rich matrix. The re doping (er3+ or eu3+) shows that re environment depends on the size of the containing np: the bigger it is, the more the proportions of embedded re and mg increase. Thus, this mg-rich environment enables re ions to increase their oxygen coordination and to no more aggregate to each other to satisfy this natural trend. A simulation of the high-temperature drawing of silica-glass confirms the existence of an anisotropy in optical fiber, explained by the persistent orientation that small silica rings acquire in this fiber, and manifests itself by an elastic anisotropy. The nontrivial effects induced on np by these extreme conditions of temperature and stress can be studied later. The crystal-field model can be used to correlate the changes of the re environment with their spectral response
Essafri, Ilham. "Microstructure of binary mixtures in bulk and nanoconfined phases". Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S130.
The study of hydrogen bonded liquids under nanoscale confinement were the focus of this thesis. By molecular dynamics simulations, we've investigated the physical behavior of binary liquids in bulk and nanoconfined phases. By tuning the surface chemistry of the nanopore to mimic hydrophilic and hydrophobic confinement, we show that it is possible to control the structural characteristics of the core–shell structure. Thereon, a core–shell organization was evidenced such that one of the liquids was strongly anchored to the solid surface whereas the other was confined at the center of the pore
Chahbani, Mohamed Hachemi. "Séparation de gaz par adsorption modulée en pression : modélisation des écoulements et de la cinétique de transfert de matière". Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL108N.
Bureau, Emmanuel. "Propriétés physiques et étude des cinétiques de relaxation à la transition vitreuse pour des polymères à base d'éthylène-co-acétate de vynile". Rouen, 2004. http://www.theses.fr/2004ROUES019.
This work is placed in the study of molecular dynamics at glass transition for polar polymers. Firstly, we have studied the characterization of few polymer serials. Secondly, we are interested to the study of molecular relaxation in the glassy state and in the glass-forming liquid state. So, we have studied three serials of materials: EVA with different content of VA, EVA hydrolyzed with different reaction time, blends of PVC/EVA. We have determined the glass transition, cristallinity and thermal degradation for each material. These results allow knowing the structure of polymers. In collaboration with chemistry laboratory UMR 6522, we correlated the material structure with the permeation properties. Indeed, these polymers used in packaging for food and good selectivities of these membranes are very interesting. Moreover, three materials (EVA containing 70% in weight of VA, PVC and a blend of these two polymers have been studied for determine the molecular dynamic at glass transition. The glass state has been characterized by Tool-Narayanaswami-Moynihan model, thus permit to understand the structural relaxation in glass. For the glass-forming liquid, we have used the Vogel-Tamman-Fulcher model and Arkhipov model. This last tries to explain all the relaxation phenomena in the glass-forming liquid. In one hand, we demonstrated that this model allow to determine the distribution of cooperative rearranging regions at glass transition in material and the a relaxation cooperativity. In regard to the fragility concept, the energy landscape is good predicted by the Random Walk Model. In another hand, we have demonstrated that the molecular dynamic is strongly correlated at the polarity of materials
Coquerel, Gérard. "Etude de dérives chiraux de la fenfluramine et de la norfenfluramine en vue de la séparation par cristallisation préférentielle". Rouen, 1986. http://www.theses.fr/1986ROUES045.
Turlier, Jérémy. "Simulation par dynamique moléculaire de la formation et du devenir sous étirage de nanoparticules diélectriques dans la silice dopée terre rare". Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0004.
With the aim of monitoring luminescence properties in rare-earth-doped silica-based optical fibers, a new strategy consists in encapsulating luminescent ions within oxide nanoparticles, in order to control their spectroscopic behavior. Nanoparticles are formed in situ through phase separation phenomenon within MgO–SiO2 binary melt during MCVD process of preform fabrication. The preform is then transformed into a fiber. During the drawing step, nanoparticles undergo glass flow effects and can elongate and break-up into smaller nanoparticles. This phenomenon raises many questions, notably about the drawing effect over nanoparticles size distribution. But it also offers new possibilities for optical property tailoring. By means of molecular dynamics, we investigated rare-earth-doped nanoparticles structure within the preform as well as within the fiber. Using an interatomic potential reproducing the phase separation within MgO–SiO2 binary melt, we showed that silica depolymerization occurring inside nanoparticles released bridging oxygens from the SiO4 tetrahedral network, increasing rare-earth ions coordination, leading consequently to a weaker clustering effect. We also corroborated that drawing process induced elongation and break-up for larger nanoparticles
Frédérix, Caroline. "Étude de mélanges de polyéthylènes couvrant une large gamme de taux de cristallinité dans la perspective d'élaboration de matériaux à gradient de propriétés mécaniques". Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10182/document.
The extremely large variety of molecular architecture and crystal morphology of polyethylene (PE) materials results in a wide range of properties of these materials. Different types of PE were blended and assembled in the aim to understand their compatibility and the resulting mechanical properties. ln this study, two ethylene-octene copolymers, i.e. an ultra low density polyethylene (UL) and a linear IOl\" density polyethylene (LL) from the metallocene catalysis, and a high density polyethylene (HD) obtained by Ziegler-Natta polymerization, were used. Binary blends were processed by extrusion and characterized by several complementary techniques:dvnamic melt rheology in the aim to study the miscibility in the melt, thermal analysis to determine the melting behavior and the crystallization kinetics, MFA microscopy and X-ray diffusion for the morphology investigation at various scale levels. The phase separation seems to apply to every blend of this study, with a low mutual solubility. However. a semi-crystalline phase with a composition gradient has been shown to occur at the intertàce of the unlike phases. Due to the quite broad distribution of the co-units in the se materials, the presence of structurally similar chains in the components creates an opportunity for partial miscibility and co-crystallization. The incidence of this structural organisation on the efficiency of welding of bilayer assemblies was assessed by mechanical testing
Coupe, Stéphane. "Applications des techniques de biologie moléculaire à l' étude de la contamination environnementale par des parasites d' intérêt médical et vétérinaire : valorisation industrielle". Paris 6, 2005. http://www.theses.fr/2005PA066395.
Yahia, Marei Abdelrahim Mohamed. "Bio(molecular) control of selective ion transport, gas separation and catalytic enzyme-based reactions using functionalized membranes". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS251/document.
Different research works have been described in this thesis. The research works can be summarized as the following. The first chapter deals with the identification of effective potent inhibitors for the human carbonic anhydrase I (hCAI) isozyme. Considering the pharmacological importance to find selective CA inhibitors (CAIs) and CA activators (CAAs), human carbonic anhydrase I (hCAI) has been subjected to a parallel screening of various constitutional dynamic libraries (CDL). In the second chapter, constitutional dynamic networks have been used in liquid and solid membrane systems as a carrier network for transporting lanthanides. The transport is based on the complexing ability of lanthanides metals (La+3, Lu+3, and Eu+3) with the functional polyether groups in the membrane materials. In the third chapter, the proposed approach consists in using supported ionic liquid membranes (SILMs) comprising two different carbonic anhydrase enzymes, the thermo-resistant SspCA enzyme and the Bovine-CA enzyme, which catalyze the reaction of reversible conversion of CO2 to bicarbonate, enhancing the driving force for CO2 transport. Membrane stability, CO2 and N2 permeability and (CO2/N2) ideal selectivity were determined for the membranes developed. In the fourth chapter, the research work consists in the synthesis and characterization of dense polymeric membranes for gas separation application. The gas permeability measurements for the synthesized polymeric membranes showed that the permeability of CO2 is higher than other used gases (N2 and CH4). In the last chapter, two different methods of PVDF membrane functionalization with a phosphotriesterase (PTE) enzyme have been developed to construct biocatalytic membrane reactor (BMR) for bioconversion and selective separation of paraoxon substrate. The first method employs reversible dispersion of magnetic nanoparticle immobilized with PTE using an external magnetic field on the surface of native PVDF membrane. On the contrary, the second method comprises chemical grafting of the PTE enzyme, after surface modification of the native PVDF membrane (DAMP-GA-Enzyme). Both methods of enzyme immobilization showed good efficiency and sensitivity towards the bioconversion of paraoxon substrate at different conditions applied in a biocatalytic membrane reactor (BMR).In general, the concepts developed in this thesis research work will help bring new tracks on the way to the development of a polymeric membrane for selective ion and gas separation but also for selective catalytic reaction under bio(molecular) control
Plays, Thibault. "Influence d’un champ magnétique sur la séparabilité d’un mélange de molécules paramagnétiques et diamagnétiques". Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM045.
The purpose of my thesis is to evaluate the impact of a magnetic field on the separation process of a mixture of paramagnetic and diamagnetic molecules. More precisely, the system of interest is the air. Oxygen, nitrogen and argon have quite similar chemicophysical properties, so the energy and the economical cost to separate those molecules are pretty high. However, the magnetic properties of those three molecules are different : the oxygen is paramagnetic whereas the nitrogen and the argon are diamagnetic. The internal energy of oxygen increases when a magnetic field is applied to the molecule, and a force attracts the oxygen towards the area with the higher magnetic field. The objective was to explore different ways to apply a magnetic field to our system in order to observe an impact on the possibility to separate the molecules. Literature reveals three major axes of study. The first one is the thermodynamic study of liquid-vapor equilibrium under a magnetic field. The second one is about the impact of a magnetic field on the hydrodynamic flow of gaseous air. And the le last one, concerns the magnetic membranes composed of a membrane doped with magnetic particles. Those three axes have been studied. A theoretical analysis and several experiments have been conducted to observe an impact of the magnetic field. The strategy was to explore many approaches with a multitude of prototype in order to find the most valuable solution for a separation process. For the magnetic membranes, we had neither the knowledge to synthesis one nor the time to acquire one. However, we tried to reproduce the concept to evaluate the potential of magnetic nanoparticles in a separation process. The interaction between nanoparticles and oxygen has been evaluated. A campaign of measure on the solubility of oxygen in a ferrofluide (solvent containing magnetic nanoparticles) has been conducted. We prove that the impact of the magnetic field on the liquid/vapor equilibrium is too weak to use it in an industrial separation process. The lead of a kinetic process is more encouraging. The experiments with hydrodynamic flows seem to be impact by a magnetic field, even if this impact is pretty moderate. In this work, the complexity of the simulation of the phenomenon in order to establish the best geometry and conditions for the process was described. However, the lead of nanoparticles is promising. Even if my study did not reveal any influence of the magnetic field on the solubility in a ferrofluid nor on the interaction between oxygen and the nanoparticles, literature shows impressive results for systems using magnetic membranes
Torzuoli, Lyna. "Etude de la structure des verres des systèmes TeO2-MxOy (M = Ti, TI) par diffusion totale des rayons X et dynamique moléculaire". Thesis, Limoges, 2020. http://www.theses.fr/2020LIMO0072.
This work aims to improve the structural description of the pure TeO2 glass and to give an insight of the structure of TeO2-MxOy binary glasses (M = Ti, Tl) by means of X-ray total scattering experiments and molecular dynamics (MD) simulations. We were able to determine, via Raman spectroscopy and X-ray total scattering experiments, that Tl2O causes the depolymerization of the glass structure whereas the addition of TiO2 leads to the conservation of Te(IV) environments. The MD simulations of the pure TeO2 glass and glasses within the TeO2-TiO2 system are carried out. First, we refined the Te(IV)-O interatomic potentials allowing us to reproduce TeO2 polymorphs as well as 14 crystalline structures containing TeO2. It was then demonstrated that the TeO2 glass consists largely of TeO4 and TeO3 units, giving a coordination number of 3.71, lower than that in the TeO2 polymorphs. Adding TiO2 tends to reinforce the connectivity within the tellurite framework via the reduction of the number of non-bridging oxygen atoms and the creation of Te-O-X bridges (with X = Te, Ti), which would justify the improvement of mechanical and thermal resistance of these glasses
Flores, Gonzalez Jessica. "Isotopic Enrichments of lanthanide based single molecule magnets". Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S064.
Molecular materials, and in particular those based on Lanthanides, have been extensively studied for their use in data storage, spintronics and quantum computing, as they promise high anisotropic systems and magnetic bistability of the discrete entity. Actually, in Athe last twenty-five years a plethora of compounds have been reported, thus showing slow of their magnetic relaxation and the characteristic magnetic hysteresis at low temperature. Moreover, some of the last investigations have reach blocking temperatures (temperature for which the system shows superparamagnetic behavior) at the liquid nitrogen level, hence facilitating the applicability of devices based on these molecules. However, the slow relaxation is commonly accompanied by quantum phenomena, favoring a fasten relaxation. The quantum effects open the possibility to different magnetic objects, but only if the operating mechanisms are well known. Dipolar interactions, with the neighboring molecules, and hyperfine interactions, with the metal ion, are known to be some of the reasons why this fast relaxations occurs. With the aim of acquiring a better understanding of the quantum events, and the contribution of the different interactions, different systems have been chosen to be studied in this work. Thus, the synthesis and magnetic characterization of magnetically diluted (suppression of dipolar interactions) and isotopic enrichment (tuning of the hyperfine interactions) of the different systems have been performed in order to find a general direction for the optimization of the slow relaxation process
Boixel, Julien. "Synthèse et caractérisation d’édifices moléculaires pour la séparation et l’accumulation de charges photo-induites". Nantes, 2009. http://www.theses.fr/2009NANT2138.
During this thesis project different molecular architectures were synthesized and studied to mimic the process of natural photosynthesis. The synthesis and physico-chemical and photo-physical characterizations of the new molecular architectures were performed. The different molecules were composed of an electron donor (ferrocene, polyarylamine, zinc porphyrin, zinc phthalocyanine, extended tetrathiafulvalene, and ruthenium polypyridine complex) and an electron acceptor (perylene monoimide, fullerene C60, naphthalene bisimide, gold porphyrin). These redox and/or photoactive units were linked by supramolecular interactions or by covalent bonds. A special interest was devoted to the influence of this linker on the electron transfer rate. Oligophenyleethynylene bridges enable an excellent electronic communication, whereas the triazole moiety, formed by click chemistry, exhibits lower electronic coupling. A photo-accumulative electron transfer function was also achieved with a dyad composed of a ruthenium complex sensitizer and a polyarylamine electron donor. The dyad was chemisorbed on a semi-conducteur surface (TiO2) and, for the first time, a double photoinduced electron transfer upon two successives excitations was demonstrated without the use of a sacrificial electron donor
Joinet, Angélique. "Production de faisceaux d'ions radioactifs chimiquement réactifs par séparation en ligne". Paris 11, 2003. http://www.theses.fr/2003PA112163.
The isotope separation on line method allows to produce by spallation, fragmentation or fission reaction, radioactive ion beams far from the valley of stability. A thick target is irradiated by a high intensity primary beam. Therefore, high production can be achieved. The problem is to find target material that releases rapidly at high temperature, the reaction products stopped into the target. This radiochemical method, optimised to work with an ion source, is based on the thermochemical properties as vapour pressure, diffusion and desorption. The delay due to the mass transfer will have some consequences on the production efficiency, and particularly for the short half life isotopes. This technique has been inefficient for the 14 and 16 group elements, which are chemically reactive in their production environment. The introduction of the chemical evaporation can solve the problem. Chemical specie is introduced into the target, allowing the transportation of the element as a molecule towards the ion source. The neutron deficient selenium and sulphur radioactive ion beams and the neutron rich tin beams are of great interest for the physicist community. The goal of my work has been to optimise the target and ion source unit in order to achieve high intensity and purity. First, off line measurements allowed to find target material dealing to a fast release of these isotopes and of several elements. Afterwards, we studied the formation, stability and ionisation of the COSe, COS, SnS and GeS molecules by on line measurements. One advantage of the chemical evaporation method is to obtaine volatile molecules and to reduce isobaric contamination. This thesis has been done in the frame of the EURISOL project. This would construct a new generation accelerator, that would deliver high intensity and high purity ion beams. And this work demonstrates that a chemical physical treatment of isotopes in their environment is crucial
Anstett, Martine. "Préparation et caractérisation de nouvelles membranes de zéolithe : application à la séparation gazeuse". Mulhouse, 1996. http://www.theses.fr/1996MULH0452.
Bahout, Mona. "Propriétés photophysiques de complexes polypyridine de Fe(II), Ru(II) et Os(II) : mise en évidence d'une localisation de l'électron dans les états excités de complexes 4-phényl-terpyridine de Ru(II)". Paris 11, 1989. http://www.theses.fr/1989PA112389.
Rebolini, Elisa. "Théorie de la fonctionnelle de la densité à séparation de portée pour les énergies d'excitation moléculaires". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-01027522.
Lang, Natacha. "Nouvelles voies d'échange dans les matériaux mésoporeux : application à la séparation azote-oxygène de l'air". Lyon 1, 2003. http://www.theses.fr/2003LYO10169.
Sharkas, Kamal. "Développement de nouvelles méthodes hybrides en théorie de la fonctionnelle de la densité par séparation linéaire de l’interaction électronique". Paris 6, 2013. http://www.theses.fr/2013PA066765.
This thesis draws together methodological contributions to the hybrid methods in density functional theory (DFT). The combination of DFT and several wave function methods has been done by linear separation of the electron-electron interaction in the multideterminantal extension of the Kohn-Sham scheme. Aiming at improving the calculation of (near-)degeneracy correlation effects in molecular systems, we have developed the multiconfigurational hybrids which combine DFT with a multiconfiguration self-consistent field calculation. The coupling between DFT and second-order Møller-Plesset perturbation theory (MP2) has provided the theoretical justification and development of double hybrid approximations which have been tested for molecular and extended systems
Oustric, Mireille. "Défauts et séparations de phase dans alinas préparé par épitaxie par jets moléculaires influence sur les propriétés électriques". Ecully, Ecole centrale de Lyon, 1996. http://www.theses.fr/1996ECDL0045.