Tesi sul tema "Membranes bipolaires"
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Van, Volden Olivier. "Les membranes d'électrodialyse :propriétés physico-chimiques des membranes monofonctionnelles constituant les membranes bipolaires". Doctoral thesis, Universite Libre de Bruxelles, 2000. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211783.
Coux, Michel. "Conception et optimisation d'accumulateurs plomb/acide de type bipolaire : Étude et réalisation de membranes bipolaires composites allégées". ENSMP, 1998. http://www.theses.fr/1998ENMP0828.
El, Moussaoui Rachid. "Synthèses de membranes bipolaires et études de leur perméabilité ionique". Doctoral thesis, Universite Libre de Bruxelles, 1995. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212537.
Lin, Teng Shee Fabrice. "Optimisation et rationalisation de la transformation du chitosane en oligomères par électrodialyse avec membranes bipolaires". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24826/24826.pdf.
Bazinet, Laurent. "Séparation des caséines du lait bovin par électro-acidification avec membranes bipolaires et caractérisation des isolats". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/NQ53999.pdf.
Dibiani, Rachid. "Comportement des membranes bipolaires sous l'effet de mesures électrochimiques à l'état stationnaire et dans des conditions transitoires". Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211580.
Doss, Nizar. "Plaques bipolaires dans une pile à combustible à membrane : effet du design sur les performances et recherche de matériaux métalliques adaptés". Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL068N/document.
This work is a contribution to the study of the role of bipolar plates on the operation of fuel cell membrane, in particular the effect of the design of these plates as a distributor of reactive gases, and the search for metallic materials that can replace conventional carbon materials .The performance of fuel cells are limited by , among other problems related to thermal hydraulics : dewatering membranes and waterlogging distribution channels gas . This performance is also limited by the type of membrane and bipolar plates used . This thesis deal primarily a comparison between membranes and bipolar plates . We also investigated problems related to moisture , especially the '' water flooding in the channels of a fuel cell by visualization tests : the evacuation of liquid water is highly dependent on the etching platesIn addition, we have searched for metallic materials candidates embodiment to replace the bipolar plates of graphite, cumbersome and costly . Two materials have been studied : 316L stainless steel and the nickel - tungsten deposited on a copper plate . The 316 L stainless steel , used as material for bipolar plates , shows good resistance to aggressive conditions within the fuel cell membrane, as shown by tests carried out over nearly 1000 hours
Abou-Diab, Mira. "Production éco-circulaire de peptides antibactériens, antifongiques et antioxydants déminéralisés à partir d'hémoglobine bovine par électrodialyse avec membranes bipolaires : étude de faisabilité, mécanisme enzymatique, optimisation des paramètres, comparaison avec l'hydrolyse conventionnelle et prévention du colmatage". Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUR031.
Bovine cruor, a slaughterhouse waste, is produced in large quantities all around the world. This co-product was mainly composed of hemoglobin, a protein rich in bioactive peptides after its enzymatic hydrolysis. However, during conventional hydrolysis, chemical agents are necessary to adjust/regulate the pH of the solution and the final hydrolysates produced contain high levels of mineral salts. Therefore, in this study, it is proposed to apply, for the first time, a green technology, named electrodialysis with bipolar membrane (EDBM), as an alternative method to the conventional enzymatic hydrolysis of hemoglobin to obtain purified bioactive peptides. The main objectives of the present thesis were to test the feasibility of this new process to produce bioactive peptides from bovine hemoglobin, to establish the optimal conditions, to avoid membrane fouling and to apply a new original « multiple-step » EDMB process allowing the production of demineralized bioactive peptides without the addition of chemical salts. Bipolar/monopolar (anionic or cationic) configurations using the H+ and OH- generated by the bipolar membranes to regulate the pH were investigated and compared to a conventional process using chemical acid and base. The EDBM configuration formed with cationic membranes allowed the production of hydrolysates containing a low concentration of mineral salts but with fouling formation on the cationic membrane, while EDBM configuration formed with anionic membranes allowed the production of hydrolysates without fouling but with a similar salt concentration than the control. Based on these results, a new 3 compartments EDBM configuration was carried-out for denaturing the hemoglobin, inactivating the enzymatic reaction and demineralizing up to 85% the hemoglobin hydrolysate simultaneously. However, a fouling was still observed on the anionic membrane due to hem precipitation. For this reason, an additional step of discoloration was tested before the demineralization to avoid fouling using the electrogenerated acid. The discolored and demineralized peptides recovered showed antioxidant activity, antibacterial activity against many bacterial strains (Gram + and Gram -) and for the first time antifungal activity against many molds and yeasts strains. Moving towards a circular economy, this sustainable technology has found to be effective in performing multiple operations simultaneously and has a great potential for industrial hydrolysis of blood, since it produces purified biopeptides with a low mineral content and can be used as natural preservatives on meat
Jaime, Ferrer Jesus Salvador. "Conversion du formiate de sodium en acide formique et hydroxyde de sodium par procédés électromembranaires : rôle de la diffusion à travers les membranes et modélisation de l'électrodialyse à membranes bipolaires". Châtenay-Malabry, Ecole centrale de Paris, 2008. http://www.theses.fr/2008ECAP1107.
In this work the conventionally electrodialysis (CED) was used to concentrate a dilute solution of sodium formate up to a concentration of2 mol L-1. Then, the bipolar membrane electrodialysis (BMED) has been proposed to regenerate formic acid and sodium hydroxide from the concentrated sodium formate solution. The influence of various operating parameters on the performance of the BMED, such as initial concentrations and current density, was studied for two configurations: two compartments with a cation-exchange membrane (CEM) and three compartments with a CEM and anion-exchange membrane (AEM). Il has been shown that the diffusion of formic acid and leakage of OH- are the main phenomena that limit the current efficiency and purity of obtained solutions. A small cell (Electrocell AB) was used to study the diffusion through various commercial membranes. The influence of parameters on the diffusion has been studied: the concentration of formic acid, sodium formate and sodium hydroxide, temperature, mature of membranes. These studies compare the performance between the differents commercial membranes. The diffusion tests were compared to pilote experiments. A predictivemodel based on mass balance was proposed and validated at pilot scale for two and three compartments BMED. It allows to predict the evolution of different species and current efficiency expected from the initial concentrations, the current density and temperature
Faucher, Mélanie, e Mélanie Faucher. "Optimisation à l'échelle semi-industrielle de la désacidification du jus de canneberge par électrodialyse avec membranes bipolaires : impacts sur les performances et la composition du jus". Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/29850.
Tableau d'honneur de la Faculté des études supérieures et postdoctorales, 2018-2019
La canneberge, petit fruit riche en composés phénoliques dont les anthocyanes et les proanthocyanidines, a de nombreux effets positifs sur la santé humaine. La consommation de jus de canneberge brut est un moyen d’en bénéficier, mais ce produit n’est pas toujours attrayant pour les consommateurs en raison de son manque de palatabilité et des possibles effets secondaires qu’il peut entraîner. Pour limiter ces désagréments, il est possible de désacidifier le jus de canneberge brut et parmi les méthodes actuellement disponibles, l’électrodialyse avec membranes bipolaires est particulièrement prometteuse. Jusqu’à présent les essais de désacidification du jus de canneberge par électrodialyse avec membranes bipolaires ont été réalisés sur des cellules à l’échelle laboratoire et en utilisant une nouvelle solution de récupération des acides organiques d’un essai à l’autre, ce qui limite son application à l’échelle industrielle. Le but de cette étude était, dans une optique d’industrialisation future, de tester le procédé à long terme sur une cellule semi-industrielle et de l’améliorer en réutilisant la solution de récupération d’un essai de désacidification à l’autre. Ainsi, des essais de désacidification du jus de canneberge ont été réalisés pour comptabiliser un total de 95 heures d’utilisation de la cellule semi-industrielle, sans poser de problème majeur au niveau de la résistance globale du système. De plus, le fait de réutiliser la solution de récupération des acides organiques n’a pas eu d’impact sur les caractéristiques physico-chimiques du jus désacidifié, et a permis des gains d’énergie allant jusqu’à 42,9 % après trois réutilisations, en plus de réduire les effluents du procédé. Ainsi, la mise à plus grande échelle et l’amélioration du procédé de désacidification du jus de canneberge par électrodialyse avec membranes bipolaires ont été concluantes et le transfert de la technologie en industrie est la prochaine étape à envisager.
La canneberge, petit fruit riche en composés phénoliques dont les anthocyanes et les proanthocyanidines, a de nombreux effets positifs sur la santé humaine. La consommation de jus de canneberge brut est un moyen d’en bénéficier, mais ce produit n’est pas toujours attrayant pour les consommateurs en raison de son manque de palatabilité et des possibles effets secondaires qu’il peut entraîner. Pour limiter ces désagréments, il est possible de désacidifier le jus de canneberge brut et parmi les méthodes actuellement disponibles, l’électrodialyse avec membranes bipolaires est particulièrement prometteuse. Jusqu’à présent les essais de désacidification du jus de canneberge par électrodialyse avec membranes bipolaires ont été réalisés sur des cellules à l’échelle laboratoire et en utilisant une nouvelle solution de récupération des acides organiques d’un essai à l’autre, ce qui limite son application à l’échelle industrielle. Le but de cette étude était, dans une optique d’industrialisation future, de tester le procédé à long terme sur une cellule semi-industrielle et de l’améliorer en réutilisant la solution de récupération d’un essai de désacidification à l’autre. Ainsi, des essais de désacidification du jus de canneberge ont été réalisés pour comptabiliser un total de 95 heures d’utilisation de la cellule semi-industrielle, sans poser de problème majeur au niveau de la résistance globale du système. De plus, le fait de réutiliser la solution de récupération des acides organiques n’a pas eu d’impact sur les caractéristiques physico-chimiques du jus désacidifié, et a permis des gains d’énergie allant jusqu’à 42,9 % après trois réutilisations, en plus de réduire les effluents du procédé. Ainsi, la mise à plus grande échelle et l’amélioration du procédé de désacidification du jus de canneberge par électrodialyse avec membranes bipolaires ont été concluantes et le transfert de la technologie en industrie est la prochaine étape à envisager.
Cranberry, a berry rich in phenolic compounds as anthocyanins and proanthocyanidins, has many beneficial effects on human health. To consume raw cranberry juice is a way to benefit from them, but that product presents a lack of palatability and can cause some side effects. To limit those inconveniences, raw juice can be deacidified and among all methods currently available, electrodialysis with bipolar membranes is very promising. Until now, essays to deacidify cranberry juice by electrodialysis with bipolar membranes were performed on laboratory scale cells using a fresh recovery solution from a deacidification essay to another. The aim of this work was to test the process on a larger scale for a longer period of time and to improve it by reusing the same recovery solution. Deacidification essays were performed in batch for a total of 95 hours on a semi-industrial cell and there was no major impact on the system global resistance. Furthermore, reusing the same recovery solution had no effect on the physicochemical properties of the deacidified juice, and energy savings up to 42.9% were recorded while the amount of waste produced was reduced. These positive results suggest the possibility to transfer the process at larger scale. Therefore, the next logical step for this project would be to scale-up the technology in factories for the industrial production of deacidified cranberry juice.
Cranberry, a berry rich in phenolic compounds as anthocyanins and proanthocyanidins, has many beneficial effects on human health. To consume raw cranberry juice is a way to benefit from them, but that product presents a lack of palatability and can cause some side effects. To limit those inconveniences, raw juice can be deacidified and among all methods currently available, electrodialysis with bipolar membranes is very promising. Until now, essays to deacidify cranberry juice by electrodialysis with bipolar membranes were performed on laboratory scale cells using a fresh recovery solution from a deacidification essay to another. The aim of this work was to test the process on a larger scale for a longer period of time and to improve it by reusing the same recovery solution. Deacidification essays were performed in batch for a total of 95 hours on a semi-industrial cell and there was no major impact on the system global resistance. Furthermore, reusing the same recovery solution had no effect on the physicochemical properties of the deacidified juice, and energy savings up to 42.9% were recorded while the amount of waste produced was reduced. These positive results suggest the possibility to transfer the process at larger scale. Therefore, the next logical step for this project would be to scale-up the technology in factories for the industrial production of deacidified cranberry juice.
Renaud, Valentine. "Impacts du retrait des acides organiques du jus de canneberge, par électrodialyse avec membranes bipolaires, sur sa digestion, l'apparition de l'inflammation intestinale et le microbiote intestinal". Doctoral thesis, Université Laval, 2021. http://hdl.handle.net/20.500.11794/69518.
Cranberry is a typical fruit from North America and its consumption increased due toits beneficial effects on human health. Cranberry juice is also recognized for its health benefits due to its richness in anthocyanins and proanthocyanidins (PACs). However, its high content of citric, malic and quinic acids could induce intestinal side effects when daily consumed. In addition, the composition of such a type of juice could also induce changes in the gut microbiota. Therefore, the main objective of this thesis was to demonstrate the potential effects of the removal of organic acids by electrodialysis with bipolar membrane(EDBM) in cranberry juice, on the apparition of intestinal inflammation in vitro and in vivo,as well as on the gut microbiota, while identifying the organic acid(s) responsible for this inflammation and their evolution during digestion. Firstly, an in vitro study demonstrated, for the first time, the evolution of composition of cranberry juice at each step of the digestion. Results indicated a loss in anthocyanins and PACs mainly at the gastric step while the content in organic acids was stable at the end of the digestion. Further more, it was evidenced that the content in citric acid of cranberry juice was responsible for the loss of integrity of the epithelial cells and, thereby, could induce intestinal inflammation. Secondly, a first in vivo study has shown the effect of the organic acid content of cranberry juice on the apparition of intestinal inflammation in mice. Results indicated a relation between the concentration in organic acids and the severity of the intestinal inflammation observed. Furthermore, the protective action of polyphenols, at the concentration of the juice, was decreased by the high content in organic acids. Thirdly, a second in vivo study, demonstrated the significance of the concentrations of polyphenols of cranberry juice in protecting the intestine from the occurrence of the inflammation. Experiments conducted in mice could not evidence intestinal inflammation modulated by the content in organic acids of cranberry juice, due to its high content in polyphenols. Therefore, the effect of EDBM on improving intestinal inflammation by removing the organic acid content of cranberry juice, could not be demonstrated. However, it was observed that the removal of organic acids, at different levels, induced a modulation of the composition and the functions of the gut microbiota. Finally, this thesis demonstrated the importance of the compositional aspect of cranberry juice for the apparition of intestinal inflammation and the modulation of gut microbiota when daily consumed. This thesis has also contributed to the understanding of the impact of EDBM applied to cranberry juice and its following health effects.
Ben, Ali Mohamed Amine. "Traitement d'un effluent contenant du nitrate d'ammonium par électrodialyse à membrane bipolaire". Châtenay-Malabry, Ecole centrale de Paris, 2002. http://www.theses.fr/2002ECAP0860.
Coeuriot, Vincent. "Caractérisation de l'écoulement diphasique dans les canaux des plaques bipolaires des piles à combustible à membrane". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0191/document.
This work focuses on the gas-liquid flows in the cathode plate, with the objective to observe their patterns, to understand their behavior, to estimate the pressure drops (PD) and eventually, to reduce clogging and its possible consequences in term of oxygen starvation downstream. A special emphasis is put on the effect of the channel section (typically between 0.5 and 1 mm²) and on the surface properties of the flow field plate materials. The experiments are performed ex-situ. The PD is measured locally along the channel as well as globally between the inlet and outlet, which put forward the existence of clogging/unclogging sequences. The characteristic frequency of these sequences increases with the air flow rate. The results show that the ratio of PD in two-phase flow to PD in dry flow decreases with the air flow rate while it does not seem to depend on the channel size (within the tested range). Moreover this ratio is lower with hydrophilic coating. Finally two main flow patterns (slug and annular flow) have been observed depending on the distance from the inlet and they have been simulated
Bouatia, Eloumami Souhail. "Développement de matériaux électriquement conducteurs pour les plaques bipolaires de piles à combustibles à membrane échangeuse de protons, PEMFC". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25545/25545.pdf.
Jaouadi, Meyssa. "Étude d'un procédé hybride de séparation couplant l’électrodialyse à membrane bipolaire et l’échange d'ions : application à la valorisation de solutions diluées d'acide organique". Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0208/document.
This work is dedicated to the study of a hybrid separation process involving bipolar membrane electrodialysis and ion exchange. This study is applied to the treatment of diluted effluents. The aim is first to acquire a theoretical understanding of transfer processes and mechanisms that affect energy consumption of this hybrid system. Then, in a more applied way, the objective is to be able to propose a cell configuration that allows to remove the acid from the treated solution by transferring it to a concentration compartment. This configuration must allow to obtain the highest purification rates as possible while minimizing energy consumption. Criteria aiming at optimizing ion exchange resins (strong or weak) in dilution compartment are proposed. The interest of the introduction of strong cationic resin under H+ form in the concentrated compartment is highlighted, as it enables reducing compartment resistance and hence energy consumption. Furthermore, experimental measurements successively conducted with “decoupled” and “coupled” systems identified resistive contributions of the different elements of the stack. This approach led to the determination of parameters of a model which predicts the resin bed electrical resistance in a given solution. Specific energy consumption (kWh/Kg transferred acid) was evaluated as a function of the desired purification rate. All the work led to recommendations for the cell design and for the choice of operating parameters
Jorioz, Claudine. "Effets du lithium sur les transports membranaires et sur les systèmes de transduction". Paris 5, 1990. http://www.theses.fr/1990PA05P071.
Athmouni, Nafaa. "Développement et caractérisation de nouveaux nanocomposites polymères électriquement conductueurs pour plaques bipolaires de piles à combustible à membrane échangeuse de protons, PEMFC". Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26861.
Faced to the declining of energy resources and the increase of energy pollution, many researches are focused on the production of clean and sustainable energy in order to reduce the use of fossil sources energy since they are the main source of greenhouse gases production. The Proton Exchange Membrane Fuel Cell (PEMFC) is a technology that is becoming increasingly important for clean and sustainable energy production. The PEMFC is an electrochemical device that operates according to the principle of inverse electrolysis of water. A PEMFC converts the chemical reaction between hydrogen and oxygen (or air) into electrical power, heat and water, while releasing only water steam into the atmosphere. A PEMFC consists of a bended multilayer Electrode-Membrane-Electrode (EME), where the membrane is a solid polymer electrolyte separating the anode and the cathode. This set is built between two bipolar plates used for collecting the electrical current and distributing the gas (hydrogen or oxygen) through gas flow paths etched on each face of the bipolar plates. Most of the recent research focused on the improvement of PEMFC performances, their durability and the reduction of their production cost. A lot of work was done on the development and characterization of the different elements of PEMFCs, including the bipolar plates, considered as one of the most expensive and most massive parts. The design of the bipolar plates must consider several parameters. They should combine good mechanical strength, good chemical and thermal stability, sufficient electrical conductivity and good ability to remove heat generated in the heart of the cell. Metal bipolar plates are penalized by their corrosion resistance, which causes a reduction of the cell life. Those obtained from graphite are brittle and their manufacturing cost is high (mainly due to channels machining cost). Therefore, much research is focused on the development of new concepts of bipolar plates in order to replace metals and graphite by new polymer based composites. The latter appear to be more attractive because of their good processing ability that could help reducing the production cost of PEMFCs. However, much more research has to be done on the improvement of their electrical and mechanical properties, which is the main objective of the present thesis in which we propose: i) To develop by twin-screw extrusion process an optimized polymer nanocomposite material in which conductive solid additives are incorporated, including carbon nanotubes. ii) Fabricate a bipolar plate prototype from theses optimized nanocomposites by using the compression molding process under controlled cooling. In this project, two thermoplastic polymers have been used as the matrix: polyvinylidene fluoride (PVDF) and polyethylene terephthalate (PET). Three electrically conductive fillers were also used: carbon black, graphite and carbon nanotubes. Various combinations of these conductive additives were also studied in order to develop optimized nanocomposite formulations. Through-plane electrical conductivity of the developed nanocomposites as well as their mechanical properties have been carefully characterized. The obtained results showed that not only the combination of the conductive additives influences the nanocomposites through-plane conductivity and their mechanical properties, but also the distribution of these solid additives (which in turn depends on their nature, their size and their surface properties) helped to improve these properties. It has been observed that the surface treatment of the carbon nanotubes used in this study helped to increase both through-plane conductivity and mechanical strength of the developed bipolar plate prototypes. It was also observed that the crystallinity generated during bipolar plate cooling inside the compression mold as well as the crystallization rate play an important role in the optimization of the through-plane electrical conductivity and mechanical properties.
Moisescu, Georgeta Mihaela. "Effets des champs électromagnétiques sur la membrane cellulaire et applications biomédicales potentielles". Paris 11, 2007. http://www.theses.fr/2007PA114814.
This thesis reports the effects of electromagnetic GSM mobile phones pulses (900MHz, 217Hs, 576µs) with SAR (specific absorption rate) up to 4. 6 W/kg on cellular endocytosis and mitosis. The results here presented report that the fluid phase endocytosis of different cells in culture is stimulated 1. 4 fold under GSM exposure to average SARs above treshold values from 1. 3 to 2. 6W/kg without any bulk temperature increase. The effect was revealed using two exposure setups: a wire patch cell and a TEM cell, at 30°C. The clathrin-mediated endocytosis is the endocytotic pathway perturbed by the GSM exposure. A similar stimulation was observed under exposure to electrical pulses comparable to GSM electrical component suggesting that this electrical component is at the origin of endocytosis perturbation. The GSM exposure of 2. 2W/kg local SAR applied for 1h did not affect the mitosis progression, the total mitosis duration or each mitotic phase duration in our experimental conditions
Schab, Frédéric. "Étude comparative des procédés d'électrodialyse et d'électrodéionisation : application à la fabrication d'acide lactique". Thesis, Vandoeuvre-les-Nancy, INPL, 2007. http://www.theses.fr/2007INPL035N/document.
This work deals with the comparative study of electrodialysis and electrodeionization. The possibilities to integrate the electro-membrane processes in the lactic acid fermentive production lines are investigated. Two main research ways are chosen : the first one lies in the continuous extraction of natrium lactate out of the fermentation middle. For this, an electrodialysis stack of only anionic membranes is coupled with the fermenter : approximately 95 % of lactate are removed during the operation. By comparison with a standard fermentation in batch mode, no inhibition is observed, and the productivity is increased by 13. The second way is to convert the natrium lactate in lactic acid : a high purity rate is seeked. A continuous electrodeioniation process including bipolar membranes, leading to 99,9% conversion rate, is elaborated for the treatment of diluted solutions. Finally is presented the mathematic calculation of an electrodeionization compartment : experimental points and calculated values are very similar
Aspirault, Claudie. "Impact de la température de préchauffage sur la séparation des protéines du lactosérum par acidification chimique ou électrochimique avec membrane bipolaire". Master's thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66343.
Andre, Johan. "Optimisation des propriétés de conduction électrique et de passivité d'aciers inoxydables pour la réalisation de plaques bipolaires de pile à combustible de type pemfc". Grenoble INPG, 2007. http://www.theses.fr/2007INPG0105.
PEM fuel cells have to comply with stringent cost, performance, and durability criteria. Thus, the goal of this PhD was to optimize electrical conduction properties and passivity of stainless steels (SS) for PEMFC bipolar plates. This work presents the possible problems when using SS plates and corresponding solutions, SS passive film properties, as weIl as their modifications by low cost surface treatments. Material characterizations were performed, allowing to study the behaviour of two alloys in different states and conditions representative of a PEMFC media. The plate industrial state is not convenient for direct use in fuel cell. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side
Heinze, Sylver. "Etude de l'électrolyse bipolaire de l'eau tritiée appliquée à la séparation des isotopes de l'hydrogène par perméation électrochimique à travers des membranes d'alliage Pd-Ag". Dijon, 2000. http://www.theses.fr/2000DIJOS008.
Pellerin, Geneviève. "Impact de la désacidification du jus de canneberge par électrodialyse avec membrane bipolaire sur ses propriétés bénéfiques en lien avec la santé buccodentaire". Master's thesis, Université Laval, 2021. http://hdl.handle.net/20.500.11794/70282.
The high content in phenolic compounds found in cranberry (Vaccinium macrocarpon) is associated with well-known beneficial effects on oral health. However, cranberry juice (CJ)is rich in organic acids, which are responsible for the low palatability of the product and cancause gastrointestinal discomfort. Electrodialysis with bipolar membrane (EDBM) is an ecoefficient process that can be used for the deacidification of CJ, thus removing the requirement to dilute the product prior to consumption. This study aimed to evaluate how the deacidification of CJ by EDBM impacts its effects against the etiological factors of dental caries and periodontitis. The antibacterial activities of the raw and deacidifed CJ samples were assessed on commensal streptococci (Streptococcus gordonii, Streptococcus oralis,Streptococcus salivarius), cariogenic streptococci (Streptococcus mutans, Streptococcussobrinus), and key periodontopathogenic bacteria (Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis). Moreover, the impact of CJdeacidification on the host oral defenses (oral epithelial barrier function and host inflammatory response) was investigated in in vitro models.It appears from the results that removing organic acids from the product reduced the bactericidal activities of CJ against some bacterial species included in the study, though its hould be noted that deacidified CJ had generally higher anti-adherence properties comparedto its raw diluted counterpart. On the other hand, deacidification of CJ helped preserve the integrity of the oral epithelial barrier compared to the raw beverage. However, even though all undiluted CJ samples exerted anti-inflammatory properties, exposition to deacidified CJappears to lower this property in an oral epithelial cell model. Overall, this work brought evidence that a moderate deacidification of CJ by EDBM could allow the production of cranberry juice that provides benefits with respect to the maintenance of oral health
Souissi, Mohamed Ali. "Développement et caractérisation de matériaux électriquement conducteurs à base de mélanges polymères pour plaques bipolaires de piles à combustible de type PEMFC". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28082/28082.pdf.
Nguyen, Luc. "Développement et caractérisation de nouveaux matériaux à base de PET, PVDF, et de mélanges PET/PVDF, pour la fabrication de plaques bipolaires pour piles à combustibles à membrane échangeuse de protons, PEMFC". Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26799/26799.pdf.
Lu, Wei. "Étude de l'échange d'ions modulé électriquement : application du couplage échange d'ions-électrodialyse à la séparation de biomolécules". Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL027N/document.
The present work aims to study the coupling of ion exchange and electrodialysis. This study is applied to the separation of biomolecules. One objective is to reduce the generation of saline wastewater produced by the ion exchange steps used conventionally in bioseparations. One approach has led to the design of architecture with a cyclic mode in 3 steps to purify some families of peptides without using a buffer pH or generate wastes. The experimental device consists of an electrodialysis cell in which are introduced anion exchange resins. The three steps are: loading of biomolecules on the resin initially in the carbonate form, elution with a solution of carbon dioxide dissolved in water, electroregeneration of the resin in its original form leading simultaneously to the regeneration of the carbonic acid solution. Using a modelling of the electroregeneration step, simulations can improve the understanding of coupled processes as the ion exchange equilibria, the equilibria in solution, the electromigration. A second approach has then been to study the possibilities of controlling the pH by electrochemical means to limit the use of buffers. The dissociation of water, leading to the formation of protons and hydroxyl ions, has been particularly studied by accounting the properties of contacts called « bipolar » as a result of an electric field. It was established that the choice of resin type and the current density can modify the pH. However this work must be pursued through research of architectures and operating procedures that deliver appropriate buffer capacity
Bénichou, Gilles. "Signalisation cellulaire par pontage bipolaire (mono- ou bicellulaire) au moyen d'anticorps specifiques : influence de l'isotype sur la nature du signal". Paris 6, 1987. http://www.theses.fr/1987PA066261.
Nandjou, Fredy. "Etude locale de la thermique dans les piles à combustibles pour application automobile. Corrélation à la durée de vie". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI079/document.
One of the main challenges for Proton Exchange Membrane Fuel Cells development is the performance loss, which largely limits the durability. The study of the degradation phenomena of the different MEA components is a challenge addressed by many researchers, but a study at a stack scale is needed in order to better understand the ageing mechanisms. Indeed, in an industrial fuel cell the operating conditions are not homogeneous as for laboratory fuel cells, especially as regards thermal aspects. The heterogeneities are particularly emphasized for automotive fuel cells, because of the compactness constraint of the cooling circuit. Moreover, the requirements of cold start should be considered, as well as the inertial effects of the stacks and the increased heterogeneities during the driving cycles.In this work, the effects of the temperature heterogeneities and hot spots on the automotive fuel cell performances and degradations are investigated. The study is conducted in different conditions: nominal conditions, load/thermal cycling and New European Driving Cycles (NEDC).The work is composed of an experimental study, which consists of ageing tests on fuel cells and on-line diagnosis at both global and local scales. At the end of the tests, post-mortem analyses of the aged components are conducted. In parallel, a physic-based model is developed in order to predict the local temperature and humidity in the different components of the cell. Then, the impact of the reactive gases and cooling flow fields design on the thermal and water management of the cell is investigated. Finally, the experimental and modeling results are coupled in order to investigate the correlation between heat management, water management and degradations
"Optimisation et rationalisation de la transformation du chitosane en oligomères par électrodialyse avec membranes bipolaires". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24826/24826.pdf.
"Développement de matériaux électriquement conducteurs pour les plaques bipolaires de piles à combustibles à membrane échangeuse de protons, PEMFC". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25545/25545.pdf.