Teses / dissertações sobre o tema "Filtres à air – Matériaux"
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Daouli, Ayoub. "Ab initio exploration of materials for the detection and selective capture of iodine species and nitrogen oxide". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0023.
Texto completo da fonteRadioactive isotopes of iodine, such as ¹²⁹I and ¹³¹I, are likely to be disseminated in the environment after a serious nuclear accident or a leak in fuel reprocessing facilities, under the form of highly volatile gaseous species, I₂ and ICH₃, resulting in dramatic consequences. It is therefore necessary to accurately detect these molecules and develop passive filters for trapping them. The challenge today is to find an effective solution that can be applied in nuclear conditions. In particular, the presence of other gaseous species called contaminants, such as CO, H₂O and O₂ can affect the performance of materials used to detect or trap these iodine volatile species in a perennial manner. Molecular scale simulation methods provide a fundamental understanding of the observed phenomena, providing in-depth knowledge at the atomic level that is often difficult to obtain by experimental methods. In this work, density function theory (DFT) calculations and grand canonical Monte Carlo (GCMC) simulations have been used to identify promising materials for the detection and capture of gaseous molecules. Regarding sensing, graphene, and two-dimensional carbon materials (BC₃, C₃N, BCN₆-2) are promising candidates. For graphene, our results reveal that in terms of thermodynamic selectivity, PG (pristine graphene), Cu_PG (copper-doped pristine graphene) and to a lesser extent Ag_MG (silver-doped monolayer graphene) are clearly the most interesting graphene monolayers for the selective capture of I₂, ICH₃ in the presence of CO, H₂O and O₂. As far as 2D carbon materials are concerned, results of adsorption on C₃N seem very promising insofar the difference between the adsorption energies of (I₂, ICH₃) vs (CO, H₂O) is very significant. These findings are strengthened by simulations at finite temperatures. In addition, a discussion of electronic structure calculations is also provided. For trapping, we have selected a class of porous materials named Metal-Organic Frameworks (MOFs). Our systematic evaluation of the adsorption performance of M-MOF-74 where M = Mg, Zn, Cu, Fe, Co, Ni and Mn showed that from a thermodynamic point of view, Fe-MOF-74 and Cu-MOF-74 are clearly the most interesting structures for the selective capture of iodine compounds. A second application addressed in this thesis, still in the context of noxious gases, is the adsorption of NOx emissions. These emissions in a confined work environment without ventilation or treatment represent a major concern. Recent studies have revealed that zeolites can provide effective capture of NOx. In this context, our results reveal that from a series of divalent cations-exchanged zeolite (Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Fe²⁺, Cu²⁺, Zn²⁺, Pd²⁺, Pt²⁺), Faujasite Y-Pt²⁺, is an interesting material for the selective adsorption of NOx from diesel engine exhaust in the presence of water vapor. We then have extended our explorations to MOFs by integrating the same cations as metals into the catecholate ligand prior to its incorporation into the cage-like UiO-66. GCMC simulations implementing a new NOx/MOF force field were deployed to gain an in-depth understanding of the microscopic mechanism involved. Our molecular simulations indicate that the nanoporous UiO-66-CatFe(II) would be an excellent adsorbent for NOx capture, even at very low concentrations of a few ppm. This complements the portfolio of porous materials that, to date, have been almost exclusively tested under operating conditions involving higher NOx concentrations (>1000 ppm)
Mokthari, Ilham. "Synthèse et caractérisation de polyimides poreux à faible constante diélectrique". Chambéry, 2005. http://www.theses.fr/2005CHAMS049.
Texto completo da fonteThis research work concerns the elaboration of low dielectric constant materials to be used as interlayer dielectrics in microelectronics. The strategy adopted for the generation of porosity relies on the thermal degradation of thermolabiles polycaprolactone sequences simply dispersed or covalently linked to thermostable polyimide matrices, slightly crosslinked by a photochemical process. The first part of this work is devoted to the synthesis and characterization of different polyimides matrices. In a second part, functionnalized polycaprolactone segments (amine-PCL or diamine-PCL) have been synthesized, characterized and involved in a polycondensation reaction in order to end up with controlled architecture copolymers. The last part of the work is related to the elaboration of porous materials. First, the experimental conditions suitable for a complete elimination of the thermolabile segments without any mage to the polyimide matrix have been determined. Therefore, a precise study of the influence of different parameters (polyimide structure, glass transition temperature, polycaprolactone proportion introduced. . . ) on the elaboration of porous structures have been realized. The results obtained suggest at two parameters are crucial for the elaboration of porosity : a high transition temperature of the matrix as well as a phase separation of the thermolabile segments in the themostable polymer
Shirkovskiy, Pavel. "Conjugaison de phase ultrasonore pour la vélocimétrie des écoulements gazeux : investigations des potentialités en micro-fluidique". Phd thesis, Ecole Centrale de Lille, 2010. http://tel.archives-ouvertes.fr/tel-00604511.
Texto completo da fonteBadoil, Bruno. "Contrôle spectrophotométrique large bande de filtres interférentiels en cours de dépôt". Aix-Marseille 3, 2007. http://www.theses.fr/2007AIX30047.
Texto completo da fonteBroadband optical monitoring for thin-film filter manufacturing is more and more developed thanks to better performances of spectrometers with array detectors. With our broadband system developed during this thesis work, we have two monitoring channels, a transmittance and a reflectance one. The two spectral responses are recorded simultaneously at each turn of the substrate holder over an extended spectral range [400 nm ; 1000 nm]. The use of such an optical measurement system enables a real time re-engineering process of reoptimizing the coating design after each layer. In situ determination of the real and imaginary parts of refractive indexes are possible too. Index characterization and manufacturing results are shown in this work
Lombardi, Mariangela. "Élaboration de matériaux céramiques cellulaires pour la réalisation de filtres à particules fines ou de substituts osseux". Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0018/these.pdf.
Texto completo da fonteL’objet de cette thèse est la mise au point d’une méthode pour l’élaboration de matériaux céramiques poreux et leur caractérisation mécanique. Les matériaux poreux ont été préparés en vue d’applications à température ambiante (en particulier, pour la filtration des particules en suspension dans l’atmosphère suite aux émissions des véhicules et des installations de chauffage) et biomédicales (comme substituts osseux). Le procédé mis au point dans cette thèse est une combinaison entre la technique basée sur l’utilisation d’agents porogènes et le gelcasting. En particulier, la méthode décrite dans cette thèse se base sur la gélification d’une gélatine naturelle. Des billes de polyéthylène sont ajoutées à la barbotine pour la création des pores dans le matériau céramique après frittage. Une poudre d’alumine alpha a été utilisée pour la mise au point de cette méthode, pour évaluer l’influence du taux de particules organiques sur le comportement mécanique des matériaux poreux. Enfin, en vue de l’application biomédicale de ces matériaux, une poudre d’hydroxyapatite a aussi été utilisée sans, et avec, les sphères de polyéthylène pour préparer des échantillons poreux à 60 % en volume
Lottiaux, Michel. "Caractérisation des couches minces d'oxyde de titane pour filtres optiques". Aix-Marseille 3, 1987. http://www.theses.fr/1987AIX30103.
Texto completo da fonteBadev, Alexandre. "Matériaux diélectriques à faibles pertes utilisés comme résonateurs et filtres dans les circuits micro-ondes". Toulouse 3, 2008. http://thesesups.ups-tlse.fr/480/.
Texto completo da fonteWith the request for information exchange via wireless communications, the needs for equipment using microwaves and microwave technology have been increasing in the last 10 years. At the beginning of the 21st century, relating to the field of telecommunications and aerospace, the microwave devices were miniaturized. Dielectric pellets were used as resonator-oscillator components, respectively micro-strip lines were integrated as waveguides. It should be noticed that a single microwave material is not universal and therefore cannot be used in a wide frequency range. The devices used in wireless communications tend to have smaller dimensions and larger capacity. Therefore the operating frequency shifts to a higher range, notably the GHz domain. Dielectric resonators are used in microwave integrated circuits in order to concentrate electric fields within the resonator body. Their quality factor (Q) is similar to that of resonant cavities, as they reflect a high linearity at high power levels. They are commonly used as frequency stabilizers for oscillators operating in the microwave frequency range. A dielectric resonator is characterized by its three main properties: a relatively high dielectric permittivity (er), low dielectric losses (tan d), and a thermal stability at a given resonant frequency (tf). The dielectric constant is a criterion for miniaturization of the resonator because the dielectric permittivity is inversely proportional to its size. The low loss (or high quality factor) allows greater selectivity of the bandwidth at the resonant frequency, a better noise suppression and low loss of transmitted power. .
Houndonougbo, Fiffamen Alphonsine. "Conception, réalisation, test et optimisation de filtres reconfigurables en fréquence intégrant de nouveaux matériaux ferroélectriques". Limoges, 2010. https://aurore.unilim.fr/theses/nxfile/default/e13e9767-8e0b-4889-8231-2d704147e6c2/blobholder:0/2010LIMO4068.pdf.
Texto completo da fonteThis thesis work discusses the design, manufacture, testing and optimization of a two-pole tunable band-pass filter, integrating new ferroelectric materials developed for a project of the National Agency for Research, ACOR2. In the first step, MIM (Metal-Insulator-Metal) capacitors, interdigitated capacitors and resonators were studied to assess the performance of materials and guide manufacturers to optimize the properties of the intended application. Then, the ferroelectric discrete capacitors were associated with microstrip resonators etched on alumina substrate to create two-pole tunable Bandpass Chebyshev filters of 6. 6 % fractional bandwidths. The filters tune from 380 MHz to 420 MHz (10 %) under a 1. 5 kV/mm electrical field. The insertion loss is -2. 9 dB at zero bias and the return loss was better than 11 dB at 420 MHz
Dionne, Pierre-Olivier. "Étude expérimentale et comparative de l'érosion de contact entre un till et différents matériaux filtres grossiers". Master's thesis, Université Laval, 2021. http://hdl.handle.net/20.500.11794/70263.
Texto completo da fonteContact erosion is an internal erosion process that can be found in embankment dams and dikes which can lead to failure. It is defined as the pullout and dragging of fines from a base material through an adjacent coarser material under seepage parallel to the interface. This study intends to understand and to identify the mechanisms that control contact erosion with a well-graded base soil (Romaine 3 till) combined with different filter materials. To study the erosion process, a new experimental setup has been developed. Also, in order to properly assess the mechanisms involved with a well-graded base soil, comparative tests have also been performed with poorly-graded base soils. It was found that the grading of the base material as an important impact on the initiation and progression of contact erosion as different mechanisms such as paving and clogging can develop to limit or even stop the erosion. With the experimental results of this study as well as those found in the literature, a model for contact erosion threshold evaluation is proposed. Additionally, an experimental approach is proposed in order to simplify the study of contact erosion for well-graded base soils. Finally, a conceptualization of the erosion process (initiation and evolution) depending on the grain size of both filter and base soils and on the hydraulic solicitation is proposed. The Romaine 3 till susceptibility to contact erosion is assessed with latter conceptualization.
Courrèges, Stanis. "Les matériaux ferroélectriques et supraconducteurs appliqués à la conception de dispositifs microondes". Limoges, 2007. https://aurore.unilim.fr/theses/nxfile/default/1310462e-e3ee-4477-9c6d-aa828a54b786/blobholder:0/2007LIMO4024.pdf.
Texto completo da fonteFirst of all, this manuscript deals with the input multiplexer channel superconductor band pass filters, with high selectivity, high Q and narrow bandwidth, for satellite applications. Tuning methods are developed with respect to the stringent specifications and limit the losses caused by the usual methods. The central frequencies of the superconductor filters are adjusted by taking into account the responsible and controllable physical parameters. An extra method is suggested to obtain a little frequency tuning after this first step and respect rigorously the specifications. Secondly, a 2D/3D static and electromagnetic analysis, based on the method of lines, of microwave planar tunable devices including ferroelectric thin-film is presented. This software can characterize the ferroelectric layers: determination of the permittivity versus the applied electric field
Benesse, Marc. "Filtration sur médias fibreux tissés en traitement d'air : Contribution à l'étude de la capture des particules". Nantes, 2005. http://www.theses.fr/2005NANT2014.
Texto completo da fonteIn order to develop an adsorption/filtration combined system for air treatment, this study proposes to characterise and model the filtration properties of an activated carbon fabric (ACF) usually used in COV treatment by adsorption. After the conception and the experimental validation of the setup, the characterisation of filter properties for solid particulate matter (PM10) capture shows the advantage to use multi layers of ACF to increase filter efficiency. Moreover, a model is elaborated to predict the global collection efficiency of woven fibrous medium in stationary filtration regime. Finally, a numerical model of flow through a woven fibrous medium associated with forces balance equation acting on particles is used to calculate the particles trajectories. This study helps to identify particles capture mechanisms in action and to localise clogging areas on the fabric
Dutheil, de la Rochère Aliénor. "Matériaux nanocomposites sur supports céramiques pour l'assainissement de l'air intérieur". Thesis, IMT Mines Alès, 2019. http://www.theses.fr/2019EMAL0011.
Texto completo da fonteIn developed countries, people spend more than 85% of their time in enclosed areas. Yet, air can carry pathogenic microorganisms such as Mycobacterium tuberculosis or Legionella pneumophila. In this context, the microbiologic quality of indoor air is an issue of common interest. Air treatment technologies for the microbial disinfection of indoor air do exist. However, most of them need external energy inputs and some do produce harmful compounds (nanoscale powders, ozone) when used. Therefore, the main goal of this thesis is to develop new antimicrobial materials for the disinfection of indoor air. These materials shall not need any energetic assistance and shall not release harmful compounds. To achieve this goal, this thesis focused on functionalizing the surface of macroscopic alumina beads. Several active compounds have been studied: manganese dioxide for its oxidizing properties, zinc oxide for its crystalline structure allowing the synthesis of nanoscale blades for the mechanical disruption of microorganisms and silver for its well-known antimicrobial ability. To assess the germicidal properties of these new materials, new test units have been designed. In particular, this thesis explored the use of tests units working in dynamic conditions with ambient air to evaluate the germicidal ability of materials in lifelike conditions
Andriamanjato, Razafimahazo M. "Contribution à l'étude des structures rectangulaires à ferrite : applications aux déphaseurs et aux filtres à commande magnétique". Toulouse, INPT, 1992. http://www.theses.fr/1992INPT097H.
Texto completo da fonteCazayus-Claverie, Emmanuelle. "Matériaux pour les batteries Li-AIR : nouvelles approches vers des nano-hétérostructures spinelles/graphène pour électrode à air". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066508/document.
Texto completo da fonteThis research work is focused on the design and characterisation of cobalt based oxides nanospinels anchored onto the surface of reduced graphene oxides (RGO) nanosheet, which will serve as bifunctional catalysts for the new generation lithium-air batteries. Whereas nanospinels are relatively simple to synthesize by conventional colloidal routes as nanoparticles dispersed into an aqueous solution, the synthesis we developed relies on a hydrothermal microwave treatment in the 100°C-200°C range. The main challenges of this nano-heterostructures synthesis was to create the interface between the nanoparticles and the RGO directly during the nanoparticles nucleation. RGO are very efficient microwave absorbers and could then convert microwave irradiation into heat in order to trigger precipitation of the spinel at the surface of the RGO sheet.Starting from Co3O4 as proof-of-concept material, the synthesis protocol has been successfully adapted to address binary oxides by substituting cobalt with first row transition metals such as nickel, manganese or iron. The precipitation of binary and ternary oxides was achievable thanks to a good understanding of the Pourbaix diagrams of all cations to adjust the acido-basic and redox conditions.Finally, the electrocatalytic activity of these supported spinel oxides was measured for both the oxygen reduction and oxygen evolution reactions (ORR and OER). The gap between the ORR and the OER potentials was significantly lowered by the presence of Co3O4 nanoparticles on the RGO, thus assuring the reversibility of this catalytic system, which is to be integrated in future scale-up test
Cazayus-Claverie, Emmanuelle. "Matériaux pour les batteries Li-AIR : nouvelles approches vers des nano-hétérostructures spinelles/graphène pour électrode à air". Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066508.pdf.
Texto completo da fonteThis research work is focused on the design and characterisation of cobalt based oxides nanospinels anchored onto the surface of reduced graphene oxides (RGO) nanosheet, which will serve as bifunctional catalysts for the new generation lithium-air batteries. Whereas nanospinels are relatively simple to synthesize by conventional colloidal routes as nanoparticles dispersed into an aqueous solution, the synthesis we developed relies on a hydrothermal microwave treatment in the 100°C-200°C range. The main challenges of this nano-heterostructures synthesis was to create the interface between the nanoparticles and the RGO directly during the nanoparticles nucleation. RGO are very efficient microwave absorbers and could then convert microwave irradiation into heat in order to trigger precipitation of the spinel at the surface of the RGO sheet.Starting from Co3O4 as proof-of-concept material, the synthesis protocol has been successfully adapted to address binary oxides by substituting cobalt with first row transition metals such as nickel, manganese or iron. The precipitation of binary and ternary oxides was achievable thanks to a good understanding of the Pourbaix diagrams of all cations to adjust the acido-basic and redox conditions.Finally, the electrocatalytic activity of these supported spinel oxides was measured for both the oxygen reduction and oxygen evolution reactions (ORR and OER). The gap between the ORR and the OER potentials was significantly lowered by the presence of Co3O4 nanoparticles on the RGO, thus assuring the reversibility of this catalytic system, which is to be integrated in future scale-up test
Givernaud, Julien. "Etude, conception et fabrication de dispositifs micro-ondes à base de matériaux intelligents type VO2". Limoges, 2010. https://aurore.unilim.fr/theses/nxfile/default/0ef7d7c3-180e-46e9-ad8a-305623c73fc7/blobholder:0/2010LIMO4009.pdf.
Texto completo da fonteThe researches described in this manuscript are dealing with the design and the fabrication of microwave devices based on the reversible semi-conductor to metal transition in a “smart” material: the vanadium dioxide, VO2. This transition can be triggered in different ways : thermally, electrically or optically. In a first step, the high modification of material’s electrical properties induced by temperature or by electrical current is exploited (change of three or four order of magnitude in resistivity) to realize microwave switches in coplanar waveguide configuration and secondly to prove the capabilities of some more complex devices like self resetable power limiters and tunable band stop filters. The fabricated circuits exhibit interesting characteristics, particularly concerning their electrical properties in the RF/ microwave domain (they can operate on a large frequency band with a high isolation). The aim of this work is to propose an interesting alternative solution to the others classical technologies (semi-conductors and RF MEMS devices) used in the fabrication of microwave devices
Popescu, R̆azvan Ștefan. "Modélisation du comportement des filtres en charbon actif utilisés pour l'épuration de l'air intérieur". La Rochelle, 2008. http://www.theses.fr/2008LAROS238.
Texto completo da fonteIndoor air cleaning by adsorption offers interesting solutions which haven’t been optimized, exploited and not even explored. The models of activated carbon filter systems take into consideration the mixture of several pollutants characterized by low concentrations, variable composition in time, temperature and humidity. All these properties are determining the operating criteria like the designing or endurance of those systems. The first part of the paper presents a synthesized biographical study upon the chemical and physical phenomenon which are typical for the filtration processes by adsorption. The second part presents the models developed in Matlab/Simulink software by taking into account the simplified hypothesis applied for the particularities of indoor air cleaning. First isothermal and dry conditions were modeled and then the effects of humidity and temperature influence. Finally the last part describes the simulations realized with the developed models. Mono and multi compound models for dry and isothermal conditions were compared with the experimental data for 6 pollutants measured at Ecole des Mines d’Ales. The influence of humidity was studied separately making a comparison between two models proposed in the present paper. In the end the last simulations show the potential of activated carbon filters to improve the indoor air quality
Costes, Romain. "Composites ferroélectriques/diélectriques commandables pour résonateurs accordables & déphaseurs RF/HF de puissance". Limoges, 2010. http://aurore.unilim.fr/theses/nxfile/default/179b34ff-b0cc-42a7-b4cb-2e696a821fc6/blobholder:0/2010LIMO4074.pdf.
Texto completo da fonteThis thesis presents a study of ceramic material for integration into electronic devices such as tunable filters or power phase shifters. The literature analysis shows that ferroelectric / dielectric composites meet the requirements for these devices realization. The main difficulty of this subject is to reconcile the three main parameters of the material: a moderate permittivity: (between 30 and 1000), low dielectric losses at frequencies of interest: (less than 0. 01) , an agility as high as possible. The first Ba0. 6Sr0. 4Ti0. 99Mn0. 01O3 - MgO and Ba0. 7Sr0. 3Ti0. 99Mn0. 01O3 - MgO composites showed that there was an inhomogeneous diffusion between these two phases, affecting dielectric properties (agility, dielectric losses). In addition, cofiring of these two phases is not optimal because the differences of sintering temperature of the two phases. By saturating the BST in magnesium magnesium and lowering the sintering temperature of magnesia (by addition of — TiO2), new composites were developed. This work led to new Ba0. 693Sro0. 297 Mg0. 01Ti 0. 99Mn0. 01O3 - MgO +1%TiO2 composite materials with a good compromise agility - dielectric loss at ambient temperatures (agility by 32% under an electric field of 3kV/mm and tan δ= 0. 02 to 4 GHz ε'= 230 to 4GHz)
Martin, Tifenn. "Air-Filled Substrate Integrated Waveguide (AFSIW) Filters and multiplexers for space application". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0391.
Texto completo da fonteThe emergence of novel microwave and millimeter wave applications in the automotive and communication sectors including the internet of things (IoT), the fifth generation of mobile (5G), and the new space, require the development of new alternative technologies providing a suitable tradeoff in terms of size, weight, power, and cost (SWaP C). This change of paradigm is essentially due to the increase of data rate, leading to the growth of bandwidth. As a substantially increasing number of systems are competing for frequency spectrum occupancy, the microwave community is pushed to develop new innovative systems at higher frequency with an increased efficiency.This change of paradigm has highly stimulated the development of low cost, high performance, highly integrated, compact, and mass producible microwave and millimeter wave systems. At the heart of a system, microwave and millimeter wave filters are essential devices allowing to select the desired information. Low loss filters are highly desired in transmitter and receiver circuits to achieve high efficiency and low noise figures. The conventional way to achieve low loss performance is to use high quality factor resonators. For most high performance applications, the air-filled rectangular waveguide (RWG) technology is used to comply with the severe specifications requested by the industry. Nevertheless, this technology becomes prohibitive in terms of cost where a mass production is needed. To reduce the cost of such components, the use of the so called substrate integrated waveguide (SIW) emerging technology has been proposed. This technology benefits from low cost and highly integrated properties. The SIW technology is a good candidate for application that needs low cost with medium insertion loss, but for high performance applications, such as the emerging new space, the achieved performances are not compliant with the severe specifications, making the implementation of the SIW technology for high performance applications restrictive.Recently, the alternative air filled substrate integrated waveguide (AFSIW), based on multilayer printed circuit board (PCB) is expected to fulfill satellite constellation application requirements as it offers a compromise between the conventional RWG and SIW technologies. This structure aims to dramatically reduce the insertion loss of the propagation medium, while maintaining the high integration and low cost aspect. Hence making it a potential good candidate for future generation of satellite payloads.Taking into consideration the presented context, the work carried out during this Ph.D. thesis has been led towards the implementation of the AFSIW for the new space applications. A particular attention has been given to the proposal, analysis, development, and implementation of innovative and original concepts for microwave filtering functions. The proposed work is based on the classic waveguide theory taking advantage of the standard PCB process to allow the development of improved and novel filters and multiplexer for space applications.This Ph.D. thesis highlights the last advances made on the development of microwave filters and multiplexer using the AFSIW technology. This includes the starting ideas, theoretical demonstrations, simulations, and experimental validations with fabricated prototypes. The results of this work are promising and demonstrate the relevance of the technology for its implementation in future satellite payload systems. In fact, a sub system of a satellite payload has been developed in this thesis to answer the need of the European Space Agency (ESA) and the Centre National d’Études Spatiales (CNES). The demonstrated concepts gained from this thesis can be considered as a good base to further develop and popularize the AFSIW technology not only for space applications but also for ground systems
Abidat, Ismail. "Matériaux catalytiques innovants pour la réalisation d'électrodes à air réversibles : applications aux accumulateurs métal-air à haute densité d'énergie". Thesis, Poitiers, 2017. http://www.theses.fr/2017POIT2306/document.
Texto completo da fonteRechargeable metal-air batteries exhibit high theoretical energy densities, and could be an ideal candidate for a technological breakthrough in the field of electric vehicles and large-scale stationary energy storage. Aqueous metal-air batteries are low-cost, safe, recyclable, and have environmental footprint. Thus, the outcome of this emerging technology could offer a credible alternative to Li-ion batteries, which are reaching a technology readiness level. However, the main scientific challenge to bring these systems into a commercial reality concerns the development of bifunctional air electrodes. This requires the design of low-cost, stable and efficient catalysts for both oxygen reduction (discharge) and oxygen evolution reactions (charge). The present work focuses on various investigations of electrocatalysts derived from graphene, cobaltites and carbon/oxide composites. The main objective was the better understanding of the effects induced by their composition, their electronic and morphostructural properties on the catalytic activity and stability of materials towards oxygen electrocatalysis. Experiments were thereby conducted in order to be able to separate effects induced by chemical nature of the carbon substrate from those resulted in the incorporation of heteroatoms or from the spinel cobaltites surface properties. In addition, a part of this study dealt with the impact of the chemical nature of the electrolyte (LiOH and K2ZnOH4) encountered in real aqueous alkali Li-air and Zn-air batteries on the activity and stability of Co3O4/N;S-RGO nanocomposites towards oxygen electrocatalysis
Lecoq, Marie. "Étude du colmatage de filtres métalliques par un aérosol liquide". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0006.
Texto completo da fonteIndustrial installations often contain hazardous materials in aerosol form. High efficiency filters (HEPA) are usually the last barrier that ensure the containment of these airborne particles. In the nuclear industry, a large amount of radioactivity is handled in liquid form, that may release, in few scenarios, liquid aerosols. These particles may affect the performance of HEPA filters with a huge increase of the pressure drop, which lead in return to a significant reduction of the ventilation flowrate. In such scenarios the pressure drop increase may exceed the filter mechanical strength and induce degradations of the media and leading to a deterioration of its capacity to retain aerosol pollutants. To overcome this problem, and to protect HEPA filter, one of the solutions is to use pre-filter (more mechanically resistant but less efficient) made up with metallic fibers. To validate this approach, it is necessary to study the behavior of these prefilters, composed of a stack of different monolayers of media. In my work, I first focused on the clogging of industrial prefilters with liquid aerosol particles. Then, for a more analytical study, I study the clogging each layer separately, in order, to model, on the future, the behavior of the assembly. The microphysical of each media (thickness, packing density, and fiber size distribution) are determined. The evolution of both filter collection efficiency and pressure drop are studied along the clogging by a submicron liquid aerosol DEHS, for different filtration velocity (0,9 à 18 cm/s). For monolayer filters, I measure pressure drops in line with the previous results found in the literature. These experiments first highlight a quasi-linear increase of the pressure drop, associate with a collection of the droplets by the fibers. Then an exponential growth is measures, that corresponds to the clogging of the pores. And finally, an abrupt stabilization is observed corresponding a liquid film formation and its continuous drainage by the airflow. However, I show a more gradual stabilization for multilayer filters. A clogging scenario is proposed, and a simplistic model is established to forecast the pressure drop as a function of the mass of liquid accumulated. To this aim, I develop a new method to freeze the liquid accumulation using resin, that where further analyze using X-ray tomography
Volatier, Alexandre. "Intégration de matériaux piézoélectriques et électrostrictifs dans les dispositifs radiofréquence à ondes acoustiques". Lille 1, 2007. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2007/50376-2007-27.pdf.
Texto completo da fonteMohammedi, Mourad. "Etude de matériaux de garnissage en vue d'une réduction géométrique des filtres biologiques dans le cadre de l'assainissement autonome". Limoges, 1998. http://www.theses.fr/1998LIMO0024.
Texto completo da fonteBoni, Michele. "Air et architecture : comprendre par la matière". Paris 8, 2008. http://www.theses.fr/2008PA083587.
Texto completo da fonteProblem links to the "air like matter" concern a whole of disciplines : architecture, art, sociology, philosophy. Air is a social matter : how do we consider it? Shall we use air like a construction matter? What's the limits of this reflexion? Do we speak about "air architecture"? Do we find examples of the "air architecture"? By the explanation of Peter Sloterdijk about "Iles anthropogènes", shall we conclude that air is the best metaphor to describe the contemporary culture and society's characteristics? Is "air architecture" on the air?
Zou, Xiaoqin. "Etude de la sélectivité moléculaire des membranes à base de matériaux poreux". Caen, 2012. http://www.theses.fr/2012CAEN2012.
Texto completo da fonteZeolitic membranes, films and composites with regular pore systems are attractive for a wide range of applications including gas/liquid separation, chemical sensors, catalytic membrane reactors, and light-harvesting materials. In this study, detection, removal or reduction of pollutants from liquid and gas media using porous materials (zeolites and MOFs) assembled in films and membranes are presented. As-prepared ZSM-5 membrane by secondary growth and LTL-hemp composite by in-situ crystallization are used to remove toxic heavy metals and aromatics contaminants from aqueous solutions. Design of new materials and development of facile and efficient processes for fuel gas or vapour separations are presented. In addition to pure silica MFI membrane (Silicalite-1) applied for extraction of ethanol from aqueous solution, the focus was on the preparation of MOF [Co3(HCOO)6] membranes via secondary growth approach, and further evaluation for the upgrading of natural gas by binary gas permeation of CO2/CH4. The porous materials (zeolites and MOFs) are also used as selective and high sensitive films for detection of air pollutants. MOF films composed of Y(BTC) nanocrystals are fabricated and apply for sensing of volatile organic compounds (VOCs), such as chloroform, acetone and 2-ethylthiophene. Besides, zeolites and MOF thin films loaded with metals are prepared and used for detection of CO with low concentration in the presence of water and hydrocarbons
Barca, Cristian. "Mise au point de filtres garnis de matériaux réactifs destinés au traitement des eaux usées au sein de petites installations". Phd thesis, Ecole des Mines de Nantes, 2012. http://tel.archives-ouvertes.fr/tel-00771472.
Texto completo da fonteThomas, Daphné. "Développement de couches lipidiques fonctionnalisées pour la détection spécifique de Brins d'ADN à l'interface air-eau : application à un nouveau concept de biopuce à interface fluide". Lyon 1, 2005. http://www.theses.fr/2005LYO10298.
Texto completo da fonteAlvarez, Elsa. "Traitement de l'air habitacle par des matériaux hybrides de type Metal-Organic Frameworks". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV006/document.
Texto completo da fonteThe indoor air pollution awareness of general public and the increasing demands of regulations / recommendations, combined with a need to stand out from the competition, make limiting the concentration of VOCs (VOCs : volatile organic compounds ) in the air cockpit crucial for the automotive industry. For example, inside a vehicle, the VOCs are originated from the outside air by combustion and evaporation of fuel. However, unlike other pollutants, it may also have an inner origin from the desorption of existing chemical substances used in the manufacture of the vehicle. Thus, the capture of VOCs by adsorption is one of the challenging techniques today. In this context, activated carbon and zeolite based VOC abatement are effective and least expensive but suffers some limitations in stability, selectivity and regeneration. The aim of this thesis was to study an alternative class of 'hybrid' adsorbents i.e. Metal-Organic Frameworks (MOFs). These porous crystalline materials are built by the association of inorganic bricks connected by organic ligands. They have highly tunable structural diversity,chemical composition (metal:ligand) and porosity (pore size, surface area and pore volume). Moreover, they possess almost infinite ability to vary both the metal center and the organic ligand that is not found at this level in zeolites and activated carbons. The work was to evaluate the performance of a series of ten MOFs, having diverse architecture (size and shape of the pores, rigid or flexible networks ...), chemical properties (acidity, redox, hydrophilic / hydrophobic, ...) and stability (water temperature). In addition to the usual characterization (X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, porosimetry N2 at 77K), Infra-Red spectroscopy operando was performed to simulate the behavior of these MOFs in the presence of VOCs in conditions as close as possible to the reality. Furthermore, the most promising adsorbents were scaled up (50-100 g) and formatted/fabricated as pellets and tested for environmental simulation chamber
Burtin, Christian. "Comportement au choc de structures tubulaires en matériaux composites". Lyon, INSA, 1988. http://www.theses.fr/1988ISAL0001.
Texto completo da fonteMassenot, Sébastien. "Etude, modélisation et réalisation de composants diffractants: Contribution à l'étude de matériaux accordables et application à l'enregistrement holographique de filtres résonants". Phd thesis, Ecole Nationale Supérieure des Télécommunications de Bretagne - ENSTB, 2006. http://tel.archives-ouvertes.fr/tel-00092017.
Texto completo da fonteles fonctions destinées au traitement optique de l'information. Ce travail est basé sur l'étude de
réseaux de diffraction 1D ou 2D réalisés par technique holographique et permettant d'obtenir des fonctionnalit
és de type réseau de Bragg ou des filtres en longueur d'onde basés sur des effets de résonance. Des
outils de simulation permettant de calculer la réponse de ces réseaux de diffraction ont été développés.
Les méthodes adaptées qui ont été retenues sont la théorie rigoureuse des ondes couplées et la théorie
différentielle qui prennent en compte la nature vectorielle de la lumière. Ce travail s'est ensuite poursuivi
par l'étude de deux matériaux d'enregistrements holographiques permettant la réalisation d'hologrammes
en volume. Le premier est le photopolymère Dupont pour lequel un modèle de formation d'hologrammes
a été établi. Nous nous sommes également intéressés au matériau composite polymère cristal liquide (HPDLC)
permettant de réaliser des hologrammes reconfigurables par application d'un champ électrique.
Ces études de modélisation et sur les matériaux d'enregistrement ont permis de valider le principe de
deux filtres en longueur d'onde originaux. Le premier est un cristal photonique 2D constitué de deux
structures périodiques orthogonales. L'opération de filtrage est due à une exaltation de la diffraction de
la structure lorsque nous sommes placés au bord de sa bande interdite photonique. Le second filtre est
accordable et utilise le phénomène de résonance de plasmon de surface survenant pour les réseaux de
diffraction métalliques ainsi que le matériau PDLC comme élément ajustable.
Massenot, Sébastien. "Étude, modélisation et réalisation de composants diffractants : contribution à l'étude de matériaux accordables et application à l'enregistrement holographique de filtres résonants". Télécom Bretagne, 2006. http://www.theses.fr/2006TELB0007.
Texto completo da fonteThis thesis is in keeping with the research activities of the optics department of the ENST Bretagne concerning optical information processing functions. This work is based on the study of 1D or 2D diffraction gratings realized holographically in order to obtain functions such as Bragg gratings or resonant optical filters. Suitable simulation tools are developed to determine the theoretical response of these structures: the rigorous coupled-wave theory and the differential method, which take the vector nature of light into account. Two holographic materials used for recording volume holograms are studied: Dupont photopolymers for which a diffusion model is established and H-PDLCs (Holographic Polymer Dispersed Liquid Crystals) which can be used to realize electrically switchable Bragg gratings. These studies concerning modelling and recording materials allow us to validate the principle of two resonant optical filters. The first filter is a 2D photonic crystal made of two orthogonal periodic structures. The filtering operation is due to the enhancement of the diffraction by the structure when the incident light is at the photonic band-edge. The second resonant filter is tunable and uses surface plasmon resonance phenomena occurring for metallic surface relief gratings, the tunability being provided by the PDLC material
Shojaedin, Mohammadmahdi. "Propriétés mécaniques des matériaux du filtre et de transition du barrage Romaine-3". Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/30437.
Texto completo da fonte345092\u Granular materials containing coarse particles are widely used in the large geotechnical works, such as embankments and dams. The investigation of the mechanical behavior of these materials requires large scale testing apparatus, resulting in costly and difficult testing programs. Therefore, in most of the current projects, the specimens with finer-grained materials having parallel grading and similar physical characteristics to original materials are prepared and the results directly used in the analysis and design of the structures. However, recent studies confirmed that the role of the particle size effect caused by using this technique should be considered. To improve understanding of this effect, in the first part of this study, the influence of particle size on the mechanical properties of filter materials of Romaine-3 dam is investigated through a series of the monotonic compression triaxial tests in the drained and undrained conditions as well as repeated-load triaxial (RLT) tests. The drained and undrained tests results showed that there is no change in the slope of CSLs in q-p’ space. The RLT test results also indicate that the load-unload modulus increases with increasing in particle size. Moreover, the shape of a particle has been identified as one of the most important parameters affecting the behavior of coarse materials. Thus, the second part consists of drained and undrained triaxial and RLT tests on filter and transition materials, having rounded and angular materials respectively, with different sizes in order to examine particle shape effect. The triaxial results show that the maximum stress ratio increases with increasing in the angularity, whereas the comparison of RLT results between the rounded and angular materials does not show any clear trend.
Huet, Isabelle. "Elaboration et caractérisation de films minces de LiNbO3 et LiTaO3 en vue de la réalisation de filtres à ondes acoustiques de surface". Montpellier 2, 2001. http://www.theses.fr/2001MON20112.
Texto completo da fonteTeetaert, Véronique. "Etude de matériaux adsorbants pour le prélèvement de composés volatils odorants : Application au prélevement d'un effluent industriel". Pau, 1999. http://www.theses.fr/1999PAUU3025.
Texto completo da fonteThe objective of this work is the study of the adsoption of volatile compounds in odorous matter on adsorbent materials before their physicochemical analysis. The analysis of the odorous compounds thanks to powerful analytical tools such as Gas chromatography coupled with Mass Spectrometry, often require a concentration stage of gases to reach the thresholds of detection. A technique, easy to omplement, is adsorption on cartridges filled with adsorbents, the recovery of th sample being generally carried out by a thermal way. In this context, the choice of the adsorbent having significant capacities of adsorption and a certain selectivity with respect to the odorous molecules is not easy. The aim of the work was to test adsorbents commonly used for instance Carbosieve SIII, Carboxen 564, Carboxen 569, HayeSepQ and finally Tenax TA. The exclusively microporous adsorbent proves to be most effective for the adsorption of the model odorous molecules selected in the three odorous families (oxygenated, nitrogenated and sulphur). A study on combinations of adsorbents did not show any improvement of the adsoption of these same molecules even in the case of a complex mixtures except for the 1-propanethiol. Lastly, a study on an effluent resulting from the paper pulp industry showed the importance of the matrix. It is necessary to be freed from this matrix, mainly made up of terpenic compounds, to exploit the capacities of the adsorbents. First of all Carboxen 564 seems to show the most interesting characteristics because of its aptitude to trap as well heavy compounds then light compounds. In addition, this time, the mixtures of adsorbents such as HayeSepQ-Carbosieve SIII or HayeSepQ-Carboxen 564 seem to be interesting for trapping this complex effluent
Lavigne, Olivier. "Caractérisation des films passifs pour la définition de nouveaux matériaux : application aux plaques bipolaires métalliques des systèmes PEMFCs". Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0047/these.pdf.
Texto completo da fonteThe aim of this work is the determination of materials solutions for stamped bipolar plates used in PEMFCs systems. The 316L SS was chosen as the reference material. However, the conductivity of its passive layer remains low, and leads to a diminution of the fuel cell performances. Surface modifications of this material are thus essential. The first way developed in this work was the physical vapour deposition of chromium nitrides onto the stainless steel. Structure, as well as corrosion resistance and physical properties, of formed passive layers onto these samples, depend on the nitrogen content of the coating and the nature of the substrate. Ex-situ characterisations of ‘high nitrogen’ coating on 316L suggest its suitability for use in the bipolar plates of PEMFCs. However, the coated materials induce supplementary costs (process) and need good mechanical properties for stamping. The second way of surface modification was thus the modification of the existent passive layer formed onto the 316L. Cerium was added within the oxide layer by an electrochemical treatment. This treatment preserves the corrosion resistance of the material, and allows a decrease of the interfacial contact resistance value of 78%. Based on the above treatment, new steels compositions was proposed, including some % in weight of doping elements (Ce, Ta) in order to modify the passive film. Physical and chemical characterisations of these new materials showed their suitability for the targeted application. Indeed, these alloys display good corrosion resistance properties, as well as a great decrease of the interfacial contact resistance. In spite of the fact that these values do not reach the wanted goal, this work validates an original method of material choice
Boisbouvier, Nicolas. "Application des matériaux à Bande Interdite Photonique (BIP) pour la conception d'antennes et dispositifs associés destinés aux réseaux domestiques sans fils". Rennes 1, 2004. http://www.theses.fr/2004REN10164.
Texto completo da fonteBourdin, Delphine Marcelle Jeanne. "Composés organiques volatils émis par les matériaux de construction : impact sur la qualité de l’air intérieur". Thesis, Pau, 2013. http://www.theses.fr/2013PAUU3030.
Texto completo da fonteNowadays, buildings are more and more airtight in order to limit heat loss as much as possible. At the same time, building, decorative and furnishing materials are known to be a volatile organic compound (VOC) and formaldehyde source. The result of these two facts is that indoor air is finally more polluted than outdoor air. During this PhD, a new analytical method based on SPME/GC/MS to analyse simultaneously VOCs and formaldehyde in indoor air was developed. A new emission cell was also designed to evaluate materials emission by coupling it with SPME. All these new methods were then applied in two new buildings (a high school and a dwelling) in order to follow indoor air quality and building materials emissions during the six month following their construction. Finally, the data collected during this study were used to develop an indoor air quality modeling
Ponsaud, Philippe. "Amélioration des propriétés mécaniques transverses de matériaux composites polymérisés sous rayonnement ionisant : étude des facteurs influents". Lille 1, 2005. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2005/50376_2005_376.pdf.
Texto completo da fonteElectron-beam curing is a promising technology for manufacturing fiber-reinforced composite materials. These materials generally present insufficient transverse mechanical properties for high performances applications. This work was aimed at improving the properties of carbon fiber-reinforced composites based on epoxy acrylate matrices. Various aspects as fibers wetting, matrix shrinkage on curing, and chemistry occurring at the fiber-matrix interface were studied separately in some details. Solutions were proposed and evaluated at the lab scale and implemented on the composite materials. Significant improvements were obtained by inducing covalent bonding between fibers and matrix. In addition, a study of the morphology of UV- and EB-cured diacrylate networks was carried out to address the issue of matrix heterogeneity
Xu, Yanghai. "Matériaux de cathode et électrolytes solides en sulfures pour batteries au lithium". Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S094/document.
Texto completo da fonteLithium-air and Li-S batteries are promising techniques for high power density storage. The main challenges are to develop solid electrolyte with high ionic conductivity and highly efficient catalyzed cathode. In this work, highly conductive carbon aerogels with dual-pore structure have been synthesized by using sol-gel method, and have been used as air cathode in Lithium-air batteries. This dual- pore structure can provide two types of channels for storing discharge products and for gas-liquid diffusion, thus reducing the risk of clogging. Nearly 100 cycles with a capacity of 0.4mAh at a current density of 0.1 mA cm-2 have been obtained. For developing stable and highly conductive solid electrolyte, sulfides, especially Li4SnS4 and its phosphorous derivative Li10SnP2S12 have been particularly investigated. These compounds have been synthesized by using a two-step technique including ball milling and a relatively low temperature heat treatment. The heat treatment has been carefully optimized in order to enhance the ionic conductivity. The best-obtained conductivity is 8.27×10-4 S/cm at 25°C and the electrolytes show high electrochemical stability over a wide working range of 0.5 – 7V. Thin films have also been deposited by using the sputtering technique, with generally improved ionic conductivity. The performance of the Li-S batteries assembled with these bulk electrolytes is still to be improved, particularly by improving the ionic conductivity of the electrolyte
Volto, Patricia. "Etude de l'endommagement laser dans les couches minces optiques". Aix-Marseille 3, 1998. http://www.theses.fr/1998AIX30099.
Texto completo da fonteBouilly, Cristiana Monica. "Caractérisation de l'influence de l'humidité sur les interactions entre les polluants gazeux et les matériaux du bâtiment". La Rochelle, 2007. http://www.theses.fr/2007LAROS186.
Texto completo da fonteThe indoor air quality (IAQ) field has gained considerable interest of many researchers, interest clearly justified by the fact that the citizens spend more then 80% of their time inside of the buildings. During the past 15 years, many experimental studies have dealt with the environmental parameters (temperature, humidity, air velocity…) influence of on the volatiles organic compounds (VOC) emission and the reversible sink effect of materials. While for the temperature all this lead to a general consensus on its influence, the conclusions are very different sometimes even divergent for humidity. This appears as the main reason of our study. Our work implies an experimental study on the phenomena parameters identification involved into the pollutants transport through the building materials and a static and a dynamic modeling on the gaseous contaminants/humidity/wall interactions. To accomplish these items, the phenomena that appear in the pollutant transport process through the building materials are described. The lack in amount of data concerning the transfer coefficients give a good reason to research and to find some relations between the physical - chemical characteristics of VOC and transfer coefficients. The last part of this work implies the integration of the mass transfer models into a simulation code on the Matlab environment. This approach is similar with the thermal transfer models used by CSTB. Within these models we are able to reproduce the gaseous pollutant and humidity transfer in the materials and also we can study the humidity influence on the VOC/ wall interactions at many levels: diffusion level, adsorption and absorption level
Bourrous, Soleiman. "Étude du colmatage des filtres THE plans et à petits plis par des agrégats de nanoparticules simulant un aérosol de combustion". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0301/document.
Texto completo da fonteIn nuclear facilities, airborne particles are the vector of most of the radiological contamination. For this reason, pleated HEPA filters are one of the containment devices which are actively studied by the IRSN (Institut de Radioprotection et de Sûreté Nucléaire) to ensure the safety of nuclear exploitation. To avoid contamination of the environment, the understanding of the behavior of the filters especially in accidental situation has to be as exhaustive as possible. The most probable accident and the most penalizing for the containment devices is fire which leads to a massive soot particle production. In this case, the clogging of the filters is a problematic which has to be taken into account. Up to now, an empirical correlation has been developed to predict the pressure drop increase. The empirical nature of this correlation doesn’t allow its use in all situations. A phenomenological understanding and model of the clogging is then necessary. The following PhD work aims to reduce the pressure drop evolution to physical observations for each step of the clogging in order to model it on the most physical basis as possible. To do so, the study has been divided in two parts. The first one focusing on the behavior of flat filter by measuring the penetration of particles inside the medium and the porosity of the deposit formed on its surface. In the second part a small scale experiment based on a single pleat has been developed. Accumulation of the particles inside the pleat has been directly observed, deformation of the pleat as well as airflow in the pleat (using a PIV method) has been measured. During these experiments, pressure drop has been monitored and the measured parameters have been linked to the pressure drop evolution. Finality is to build a simple analytical model to predict the pressure drop evolution of the filters as a function of the deposited mass, the aerosol characteristics and the ventilation conditions. The main perspective opened by these results is the validation of complete numerical models to overcome the experimental limits. The logical extension of this work will be the study of the interaction of a clogged filter with temperature, air moisture and chemical aggression
Bandaly, Victor. "Etude de la persistance de virus sur les filtres des centrales de traitement d'air : influence des paramètres de procédé et impact sur la santé". Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1B038/document.
Texto completo da fonteAir pollution is one of the major public health problems of our century and especially of indoor air as we spend about 90% of our time in closed environments. Among pollutants bioaerosols have been poorly studied. However, epidemiological studies have already shown a relationship between bioaerosols and human health. The aim of this PhD work is to learn about respiratory viruses in closed environments via ventilation systems in order to study indoor air quality. At the end of state of the art of air pollutants, it is important to define those present in the air that need to be treated, ventilation systems, filtration processes by fibrous media and the processing methods being able to be implemented. The effects of viral bioaerosols on public health in indoor environments were discussed and drafted in a bibliographic review. The methodology of the study was to assess the fate of respiratory viruses, mengoviruses and adenoviruses, in a miniature experimental system similar to air treatment systems used in closed environments. The experimental system used was validated and the filter performance against viral aerosols was investigated. This study presented originality for the characterization and the fate of two non-enveloped respiratory viruses, mengovirus (RNA) and adenovirus (DNA), in indoor environments and their fate on fiber glass filter. This study showed the ability of viruses to pass through the filter and to remain infectious upstream and downstream the filter. There is scarce literature on this subject, and this project allowed us to add new relevant data on the persistence of respiratory viruses in indoor air and more precisely at the level of filters in air handling units
Farre, Marie-Thérèse. "Développement et validation d'une procédure expérimentale pour l’étude de la corrosion sous contrainte biaxiale : application aux couples alliage 600/air et 316l/mgcl 2". ENSMP, 1998. http://www.theses.fr/1998ENMP0839.
Texto completo da fonteMonlouis-Bonnaire, Jean-Philippe. "Modélisation numérique des transferts couplés air-eau-sel dans les matériaux cimentaires et les terres cuites". Toulouse 3, 2003. http://www.theses.fr/2003TOU30135.
Texto completo da fonteCharlet, Thibault. "Filtres hyperfréquences reportés en surface, à fort facteur de qualité et compensés en température". Thesis, Limoges, 2021. http://www.theses.fr/2021LIMO0010.
Texto completo da fonteIn this work, we study microwave filters for space telecommunication with two main application fields. The devices should be surface mounted, on printed circuit board to remain low-cost with a minimal bulkiness and high performances. We also want the frequency functions to be kept efficient despite the temperature shift in space. The first chapter deals with the state of the art of the field by presenting the needs: the multiphysics simulations and the filter design, the surface mounted process, and their temperature compensation. In the second chapters, we focused on the multiphysics modeling and how we have applied it in our study. We have also characterized the materials and the microwave system thanks to a dedicated measurement bench: the permittivity, the dielectric losses, the conductivity, and the frequency shift are collected to supply the databases. In the last two chapters, we designed resonators and filters. The mounted surface technologies need to be well controlled to provide sufficient efficiency for the devices. We achieve thermal frequency stability by using specific materials, non-affected by thermal effects, or through a combination of materials with specific properties to create an offset. At last, we applied these techniques to show different types of filter that can be an answer to our needs
Laur, Vincent. "Contribution à la réalisation de circuits hyperfréquences reconfigurables à partir de couches minces ferroélectriques : des matériaux aux dispositifs". Phd thesis, Université de Bretagne occidentale - Brest, 2007. http://tel.archives-ouvertes.fr/tel-00265851.
Texto completo da fonteNotre travail a débuté par la mise au point d'une méthode de caractérisation adaptée à des couches d'épaisseur très faible dans des conditions de mesure proches de celles de nos futurs dispositifs. L'analyse de couches minces KTN déposées sur des substrats différents a mis en évidence une forte influence du substrat sur les propriétés diélectriques hautes fréquences de KTN.
Par la suite, nous avons réalisé plusieurs séries de démonstrateurs (capacités interdigitées et résonateurs stub) afin de tester le potentiel des couches minces KTN pour l'accordabilité en hautes fréquences. De nombreux substrats et compositions KTN ont été étudiés afin d'identifier le couple présentant les performances les plus intéressantes. Les couches minces de KTa0,5Nb0,5O3 déposées sur saphir se sont avérées les plus prometteuses et ont été privilégiées pour la suite de nos travaux.
Puis, de nouveaux systèmes de mesure ont été mis en place pour permettre l'application de tensions de commande importantes. Plusieurs types de circuits ont alors été réalisés puis mesurés dont des capacités variables en transmission et en réflexion, des résonateurs de type coupe-bande et passe-bande, des déphaseurs et des filtres. Globalement, les performances obtenues démontrent le très fort potentiel des dispositifs utilisant des couches minces KTN en terme d'agilité. Par contre, les pertes d'insertion observées sont pour l'instant trop élevées. Les pistes actuellement explorées pour l'amélioration des performances de ces dispositifs, tant sur le plan de la réalisation des couches que de la conception des circuits, sont très prometteuses et laissent présager, à moyen terme, une intégration possible de ces dispositifs au sein de front-end multistandards.
Beaugeard, Vincent. "Développement de nouveaux matériaux fonctionnalisés pour application dans un procédé de traitement par flottation". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS229.
Texto completo da fonteAt the end of clarification process, after coagulation-flocculation steps, flocs can be removed from treated water by settling or flotation. In the latter case, Dissolved Air Flotation is the currently used process. However, this method showed important drawbacks, especially an important energetic cost due to the production of air saturated water. In that context, the goal of the reported work dealt with achieving air-free flotation using innovative floating materials. First of all, the synthesis of expandable polystyrene beads using water or ethanol as blowing agent was investigated. Other beads containing both styrene and 4-(chloromethyl)styrene were prepared. Then, surface initiated atom transfer radical polymerization of acrylamide (SI-ATRP) was achieved. Unfortunately, the expansion of such materials was not possible. Therefore, the second part focused on the functionalization of Expancel beads by “grafting from” or “grafting onto” techniques. The first step consisted in reducing some nitrile functions at the surface into primary amine ones. After functionalization with bromoisobutyryl bromide, the SI-ATRP of acrylamide was performed in water at room temperature. On the other hand, the acryloyl chloride was grafted onto amine functions, and grafting of starch was achieved using a redox initiator. All materials obtained have been used for flocculation/flotation tests and demonstrated satisfactory performances in terms of turbidity removal. Beads functionalized with starch have been successfully regenerated with oxalic acid and sodium dithionite and kept appropriate efficiency during several flotation/regeneration cycles
Caruyer, Grégory. "Modélisation, conception et caractérisation de résonateurs et filtres à onde acoustique de volume pour le filtrage RF en téléphonie mobile". Lille 1, 2005. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2005/50376-2005-Caruyer.pdf.
Texto completo da fonteLang, 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.
Texto completo da fonte