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Lorenzini, Cédric. "Elaboration de matériaux polymères issus de ressources renouvelables". Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1121.
Pełny tekst źródłaThe progressive exhaustion of the fossil resources has entrainé these last years a transfer of interest of the synthetic materials towards materials stemming from renewable resources. The latter can be developed from polymers and/or from synthons presents in the biomass. In this context, the synthesis of new biomaterials with poly (3-hydroxyalcanoate ( PHAs) and of isosorbide was realized. The obtaining of linear architectures and réticulées allowed to obtain diversified properties. At first, we prepared fonctionnalisées units, called elementary reactive bricks, with PHAs and with isosorbide. Oligomères of PHAs téléchéliques fonctionnalisés diols, dihydroxy-acid, diallyls, di-triethoxysilanes or still diepoxys was produced
Didierjean, Sébastien. "Étude du comportement des matériaux composites carbone-époxy en environnement hygrothermique". Toulouse 3, 2004. http://www.theses.fr/2004TOU30266.
Pełny tekst źródłaThe carbon/epoxy aeronautical structures are subjected to outside environments combining both temperature and humidity therefore these materials are subject to water molecules sorption by the epoxy resin. First, a model of the water propagation was implemented. It takes account of the effect of the hydrolysis taking place between the water molecules and the epoxide groups that have not been cured. This mechanism is coupled with a Fickean diffusion. The second part deals with the effects of the local water molecules presence on the elastic modulus of an elementary composite ply. The local level of water concentration is responsible for the plasticization of the polymer matrix represented by the decrease of its Simple Softening Temperature. The use of a Micro-Mechanical model of homogenization allowed to directly assess the evolutions of the elastic properties of an elementary ply. The third part is about the study of the cyclic hygrothermal environments and shows how the effects of that type of loads are different compared to their equivalent monotonous solicitations. Special attention is given to the effect on damage behaviour of the material
Kamali, Siham. "Comportement et simulation des matériaux cimentaires en environnement agressifs : Lixiviation et température". Cachan, Ecole normale supérieure, 2003. http://www.theses.fr/2003DENS0004.
Pełny tekst źródłaLamouroux, Franck. "Étude du comportement en environnement oxydant des matériaux composites 2D C/SIC". Bordeaux 1, 1992. http://www.theses.fr/1992BOR10668.
Pełny tekst źródłaMendy, Henri Joseph. "Etudes expérimentales et simulations des processus de corrosion aux interfaces matériaux métalliques-environnement". Thesis, Evry-Val d'Essonne, 2008. http://www.theses.fr/2008EVRY0026/document.
Pełny tekst źródłaThe aim of this study is, using a mesoscopic model based on cellular automata and taking into account a small number of simple processes, to explain numerical simulations obtained in order to better understand the complexity of corrosion. In the first part of this work, the model is used to simulate corrosion in a defect of material protected by an insulating layer and on a metal covered by an oxide layer. Anodic and cathodic reactions simulated in the model can take place in the same site (localized reactions) or in two different (spatially separated reactions) sites. Study of localized reactions shows the detachment of metallic islands during corrosion. These results correspond to a phenomenon which has been experimentally proven, named chunk effect, and is responsible of the deviation with Faraday’s law. It is shown that effective corrosion speed is enhanced by the production of islands resulting from corrosion-erosion coupling. Secondly studies of spatially separated reactions, have shown the influence of the diffusion of acid-basic species in the solution and have permitted to carry out, an initial regime characterised by an homogenous solution, followed by diffusion limited regime, where chemical heterogeneities leading to physical heterogeneities (roughness of the front) appear. The relationship between chemical and morphological phenomena is clearly demonstrated. Finally we have demonstrated experimental deviations with Faraday’s law in the case of zinc corrosion, in sulphuric acid medium
Chaulet, Didier. "Approche expérimentale de la mobilité des éléments durant l'altération des matériaux vitreux : Impacts environnementaux". Poitiers, 2000. http://www.theses.fr/2000POIT2298.
Pełny tekst źródłaValentin, Dijksman Laurence. "Matériaux nouveaux et théorie de l'innovation : une approche en termes de réseaux de projet". Paris 1, 1994. http://www.theses.fr/1994PA010069.
Pełny tekst źródłaPresently, the theory of innovation does not include the new technologies, in particular the new materials. However, they are very important. Owing to the innovation, they are potentially present in all fields of economy. They encourage links between participants of those various fields within networks. New materials have got coracteristics that differ from those of the traditionnal materials already present in the economy. Those caracteristics are either technical or industrial or economic. Innovation in new materials can be separated into two categories. On the one hand, the innovation of structural materials, not really strategic, is based on a "let it do" logic. It is a vertical and contractual network which results in a partition of the competences. The common culture is weak. The members of the network are consequently constrained to submit their participation to a coordinator. On the other hand, the functionnal materials are highly strategic and organise their innovation according to a "do it in common" logic. The members take part in a common project, in the limits of horizontal and informal networks with averlap of competences. Reality intermingles the respective caracteristics of the materials. The network is based on a project of innovation common to all the members. In integrates the secificities of the two logics. Rather contractual, it mixes heterogeneous competences owing to a deep knowledge circulation. That is the reason why i call it "project network". It gives importance to technology, information and knowledge
Raulet, Marie-Ange. "Contribution à la modélisation des matériaux magnétiques liés à leur environnement en génie électrique". Habilitation à diriger des recherches, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00703561.
Pełny tekst źródłaDurin, Christian. "Contribution à l'étude du vieillissement de matériaux composites carbone/epoxyde sous ambiance spatiale". Toulouse, ENSAE, 1988. http://www.theses.fr/1988ESAE0008.
Pełny tekst źródłaAdokanou, Kokou. "Etude micro et nanostructurale des défaillances d'architectures microélectroniques en environnement humide". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM064.
Pełny tekst źródłaThis thesis aims at using mechanical stress engineering to improve the reliability of microelectronic components under Temperature-Humidity-Bias testing in order to develop robust packaging technologies for space. The application is done on microware devices based on gallium arsenic (GaAs) with low noise amplifier function (LLA and LNA). We started work by analyzing failure mechanisms of MMIC devices (Monolithic Microwave Integrated Circuit) in severe environment and with the evaluation of thermomechanical induced stresses in stack layers by test temperature. We propose two methods to study the impact of mechanical applied stress on the reliability of microware devices in space qualification: the first method called “indirect” is a bending by buckling way which applies uniaxial stress (250MPa in absolute value) and the second method called “direct” with biaxial stress by treating silicon nitride passivation (SiNx) layer with nitrogen ion implantation (~ -1,2GPa). A system which applies mechanical stress and a printed circuit especially designed for this thesis. Characterization benches with connectors of probes are used to make electrical measurements of transistors and to calibrate the changes of internal stress by piezoresistive effects in semi semiconductors. Numerical simulations have been performed in Abaqus ® to evaluate thermomechanical stresses induced in layers through devices preparation and after plastic encapsulation (Dam&Fill). For each proposed method, aging test was carried out in the most severe conditions (85°C / 85%RH / inverse polarization of the gate). The results of indirect case by buckling on 1850h (A) / 2450h (B) of testing showed a significant improvement of their reliability either in tensile or compressive applied stress. Indeed, for the studied devices the presence of stress delayed considerably damage of more than 80% of aged devices. The failure analysis of failed devices was completed by finite element method simulations in Abaqus ®. We observed and blisters near the gate fingers and capacitors which are linked to the loss of static and dynamic performances. The results in the direct case by surface treatment on 1000h (A and B) of testing also showed the improvement of the reliability for all aged components. The comparison of these results with the indirect case helps to identify the nature and level of optimal applied stress to ensure a better reliability of GaAs devices under THB testing. A study of the physico-chemical behavior of the failures at the surface was also performed in order to make a link between different scales of failure: from the loss of performance until the breaking of chemical bonds through changes of internal stress of the layers
Tonon, Claire. "Modèle de comportement des revêtements de contrôle thermique en environnement spatial simulé". École nationale supérieure de l'aéronautique et de l'espace (Toulouse ; 1972-2007), 2000. http://www.theses.fr/2000ESAE0014.
Pełny tekst źródłaZombré, Wendlamita. "Durabilité des matériaux composites dans un environnement Génie Civil : expérimentation multi-échelle et analyse statistique". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1106/document.
Pełny tekst źródłaOur thesis is part of this MICRO project "Innovative Composite Materials for the Repair of Structures: Reliability approach of the dimensioning for their requalification and the prediction of their durability". Final objective of the thesis is to understand the problem of sustainability through a multi-scale phenomenological experimental approach and to propose probabilistic life-time models. So, we defined the methodology of our study, as well as the methods, materials and analysis techniques. The study material is a non-equilibrium (70% / 30%) unbalanced bidirectional carbon / epoxy that is crosslinked at room temperature and made by hand layup process. Six hygrothermal aging obtained by crossing between temperatures (20°C, 40°C and 60°C) and humidities (50%, 75% and immersion) at various times were carried out during the study. After identifying the various indicators, we carried out physicochemical analyzes (absorption-desorption, DSC, TMA, Infrared, DMA and Tomography) as well as a follow-up of the mechanical characteristics (tensile, interlaminar shear, pull-out and double shear). These indicators were analyzed statistically to more rigorously validate the trends that were observed. The monitoring of mechanical performance indicators by accelerated aging was carried out and then compared to 1 year of natural aging. The antagonism of the various mechanisms of damage has been demonstrated in the case of simple traction and interlaminar shear. It appears that plasticization is the mechanism that most affects the performance of carbon / epoxy composites. For high temperatures, it appears that post-cure by densifying the network has improved interfacial cohesion, which has inhibited the impact of thermal degradation on mechanical performance. Comparing with natural aging, it was noted that aging in an aqueous condition was more generally degrading and aqueous conditions accelerated well the degradation in a natural environment. In particular, the trends observed do not follow evolutions that permit to write simplified prediction models. The quality of the composite / concrete adhesion was evaluated by pull-out tests. The strong disparities between the results make the analysis delicate. But it has been shown that the post-cure seems to improve the cohesion whereas the plasticization is very harmful for the stability of the bonded joints accelerating excessively the degradation in comparison to the natural aging. This instability has also been proven by the double shear tests where the delamination was observed from the first maturities of aging. The anchor length is reduced and a time-sensitive model has been proposed for the selected aging condition (60°C-immersion). On the other hand, this plasticization softens the failure due to the increased deformability of the joint. In this environmental condition, the monitoring of the elastic limit stress seems to be a relevant indicator for the monitoring of the durability because it simulates the natural aging with reasonable differences. The last part of our work consisted in the proposal of a statistical treatment of the data in order to validate firstly the trends observed experimentally, to bring more information and to discuss on the choice of the models of prediction. Although, physical model is very appreciated by the community, it is not systematically applicable. Indeed, it assumes degenerative performance, which in practice is not the case. A physical approach has been proposed on the refined database in order to respect the writing conditions of the model (degenerative trends). The model chosen to predict the ultimate tensile strength is conservative but applicable for reliability studies. Bayesian enrichment can be used to demonstrate the advantage it can confer in reliability studies
Issoupov, Vitali. "Proposition d'une procédure pour la simulation de l'effet d'un environnement spatial d'orbite basse sur des matériaux composites". Toulouse 3, 2002. http://www.theses.fr/2002TOU30074.
Pełny tekst źródłaBailly, Laurence. "Etude du comportement de deux grades cyanates esters pour des applications structurales en matériaux composites en environnement tiède". Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0064.
Pełny tekst źródłaComposite materials made of cyanate ester resins and in particular phenolic triazine resins such as PT15 and PT30 are selected to replace structural metal parts in aircraft at operating temperatures between 200 and 300°C. The main advantages of these resins are their high glass transition temperature, above 300°C, and their low viscosity at 80°C make them suitable for Resin Transfert Molding (RTM) process. The main goals of this work are to understand the resins’ behavior during crosslinking and then to study their durability through thermo-oxidative aging at operating temperatures. Physico-chemical characterizations of PT15 and PT30 resins at their initial state showed a similar chemical composition and spatial configuration but a different molar mass distribution. Triazine rings have only been detected in PT30 only, indicating a “pre-cured” state. These differences have consequences on the crosslinking kinetics and promote an autocatalytic mechanism for PT30. After cure optimization, PT15 has a glass transition temperature 70°C lower than the one of PT30. Among different analysis techniques, the rheological study during crosslinking provided an understanding of the networks’ structuration dissimilarities between the two grades, highlighting the formation of an intermediate structure which relaxes at lower temperatures in PT15. This different networks’ organization is the key element to understand dissimilar thermal stabilities analyzed during thermo-oxidative aging
Latapie, Simon. "Visualisation interactive de simulations à grand nombre d'atomes en Physique des Matériaux". Phd thesis, Ecole Centrale Paris, 2009. http://tel.archives-ouvertes.fr/tel-00453299.
Pełny tekst źródłaDoungmene, Floriant. "Molécules et matériaux à base de polyoxométallates pour l’énergie et l’environnement". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112173/document.
Pełny tekst źródłaThe present work concerns the synthesis and characterisation of new polyoxometalate (POMs) based molecules and materials for applications in energy and environment matters. As far as the environment is concerned, our efforts involved the electro-catalytic and photo-catalytic transformation of pollutants such as nitrogen oxides and recalcitrant azo dyes like Acid Orange 7. As for the domain of energy, we focused on electro-catalytic systems aimed at producing dihydrogen (a high calorific power fuel) and at reducing dioxygen (an important reagent in fuel cells). These reactions usually require several electrons in order to take place, which led us to choose POM-based catalysts. In fact, POMs are capable of stocking and returning an important number of electrons without changing their structure.In the first part, several POMs in which different transition metals are sandwiched in the equatorial plane of the molecular scaffold are synthesised and characterised by experimental (cyclic voltammetry, coulometry, microbalance) et theoretical (DFT calculations) methods. These compounds have shown a very good electro-catalytic activity towards the reduction of substrates such as nitrogen oxides, dioxygen and hydrogen peroxide.In the second part, some materials exhibiting improved properties are synthesised through the incorporation of POMs in matrices like Metal Organic Framework (MOF)-type molecular networks and ionic liquid polymers. The association with a semi-conductor such as TiO₂ has also been considered. The materials obtained were characterised by several techniques: Fourier transform infrared spectroscopy, electrochemistry, diffuse reflectance spectroscopy, thermogravimetric analysis, X ray diffraction, X ray photoelectron spectroscopy, transmission electron microscopy. The POM and MOFs based materials are very performing for the electro-catalytic reduction of protons, having onset potentials better than those exhibited by platinum electrodes. The hybrids consisting of POMs, ionic liquid polymers and TiO₂ are photo-sensitive under visible light, unlike each component taken individually. They have shown a good activity towards the degradation of Acid Orange 7. In addition, the composite obtained by photo-deposition of silver nanoparticles on these materials exhibits a good electro-catalytic performance as a cathode for the reduction of O₂ and NO‾₃
Bispo, Antonio. "Contribution à l'élaboration d'une méthodologie pour évaluer les dangers et les risques liés aux matériaux solides contaminés". Vandoeuvre-les-Nancy, INPL, 1998. http://docnum.univ-lorraine.fr/public/INPL_T_1998_BISPO_A.pdf.
Pełny tekst źródłaLebaillif, David. "Fissuration en fatigue des structures mécano-soudées soumises à un environnement mécanique complexe". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2006. http://tel.archives-ouvertes.fr/tel-00695047.
Pełny tekst źródłaFriederich, Blandine. "Développement de nouveaux systèmes retardateurs de flammes à base de nanocomposites plus respectueux de l'environnement". Electronic Thesis or Diss., Metz, 2011. http://www.theses.fr/2011METZ012S.
Pełny tekst źródłaFollowing the restrictions made by the United Nations and the European Community on certain halogenated flame-retardants, the current market demand tends to move towards non-halogenated compounds such as phosphorous flame-retardants. However, it is necessary to use high amounts of material for reaching interesting fire resistance properties, resulting in a drop of mechanical properties. This led us to combine a part of the phosphorous compounds with nanoscale metal oxides, known for their ability to improve the stability of poly (methyl methacrylate) (PMMA).We have first studied the effect of nanoparticles (titanium dioxide, alumina and boehmite) on the thermal diffusivity of PMMA, in order to highlight a mode of action of these additives during the thermal degradation of PMMA. A part of these metal oxides have then been substituted by two flame-retardants based on phosphorus and nitrogen: ammonium polyphosphate (APP) and melamine polyphosphate (MPP). In the obtained ternary systems (APP/MPP/metal oxide), the properties of fire resistance and thermal stability were studied and also the mechanisms involved in the degradation. Gaseous and condensed phases have been analyzed for this purpose
Schiopu, Nicoleta. "Caractérisation des émissions dans l'eau des produits de construction pendant leur vie en oeuvre". Lyon, INSA, 2007. http://theses.insa-lyon.fr/publication/2007ISAL0076/these.pdf.
Pełny tekst źródłaThe various French and European regulatory or voluntary actions push more and more the construction products manufacturers to an environmental assessment policy. A « horizontal » approach (i. E. , applicable to one or several families of products used in a certain scenario) is considered the best route for the assessment. Moreover, it is required by the Mandate M/366 addressed to CEN. The aim of this research is to contribute to the development of this kind of approach, in order to assess the substances emission from construction products into water, during their service life. Three products were tested: concrete slabs, wood duckboards and zinc gutters. The experiments were carried out at two scales: laboratory scale (controlled conditions) and pilot scale (outdoor / not-controlled conditions, with meteorological monitoring). At pilot scale the products were exposed to meteoric water, during one year. A release model (chemical and transport modelling) was developed for the case of the concrete slabs. PHREEQC software was adapted and used. The main results show that in order to assess the substances emission from construction products into water, in a « horizontal » approach framework, the following steps are required and must take into account the product and the exposure conditions specificities: - physicochemical characterisation of the product, which could be more or less complex, depending on the product and on the knowledge already available ; - characterisation of leaching behaviour, under static (equilibrium) and dynamic conditions, which must take into account especially the use and the evolution of the product during its service life. The Continuous Monolithic Leaching Test (CMLT) seems more suitable for release dynamic assessment ; - modelling of the products behaviour in a specific exposure scenario. The laboratory data cannot be directly transferred to service conditions but they are essential for the modelling of environmental behaviour
Coque, Yves. "Proposition d'outils d'optimisation de procédé d'oxydation avancée (POA) par UV/H2O2". Pau, 2002. http://www.theses.fr/2002PAUU3012.
Pełny tekst źródłaWignacourt, Alex. "Caractérisation, mesure et évaluation des indicateurs techniques, économiques et financiers des éco-matériaux : application au secteur du bâtiment". Electronic Thesis or Diss., Ecole centrale de Lille, 2009. http://www.theses.fr/2009ECLI0020.
Pełny tekst źródłaEco-materials, have revealed a number of interesting characteristics compared with more traditional technical or architectural solutions. The criteria so far used to differentiate them were often related to the preservation of the environment or health. The main research objective has been to study the technical, economic and financial advantages of such more environmentally friendly materials by collecting selected referential information- assessment indicators and criteria- inside a proposed system of reference. The first part of my work has been devoted to identifying eco-materials in the broader context of the conception of high environmental quality buildings. The position of eco-materials in international and European Environmental Quality Management Systems for Buildings- SMQEB- has then been reviewed in a second part. The third part of this work has consisted in designing a technical, economic and financial prescription decision tool for eco –materials. In the final part, the main concern has been to implement this designed and tested methodology within the Nord Pas De Calais region. An elaborate construction system - a flat roof - has been selected to compare a set of eco-built solutions with more conventional ones. The technical, economic, financial, environmental and health criteria have in-fine been used in easily understood language: the cost/profit ratio
Kebe, Seydina Ibrahima. "Synthèse de matériaux monolithiques pour la séparation et la catalyse en phase liquide : problématiques environnementales et du développement durable". Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1127/document.
Pełny tekst źródłaPolymeric materials have gained immense popularity with the golden age of petroleum and they still today meet with great success through Green polymer chemistry approaches and numerous high added value dedicated application in scientific domains such as analytical chemistry, medicine, space investigations, where one of the key for success is the design of miniaturized objects. In this contribution, micro-sized monolithic materials have been designed though either in microchannel immobilization (I.D. = 75 µm) or surface attachment on glass substrates (hundredths of microns in thickness). Polymers exhibiting monolithic morphology were considered to benefit of high permeability, mechanical and thermal resistances which are mandatory to flow chemistry applications. With the aim to control the interfacial interaction ability, a generic monolith having N-hydroxysuccinimide ester groups was used and on purpose functionalized. Molecular segments acting as selector – for electrochromatographic applications – of metal nanoparticles ligands – for supported catalysis applications – have been immobilized on the monolith surface via classical (nucleophilic substitution) or original (photo-induced thiol-ene click) grafting reactions.The so-designed materials were characterized through spectroscopic, microscopic, diffraction, thermogravimetric methods providing insight into correlation between the observed separation and catalytic abilities and the interfacial structure of the monolith. As representative examples of application, one may cite the electrochromatographic separation of toxic molecules such as organic pollutants (phenols, anilines, polycyclic aromatic hydrocarbons, polychlorobiphenyls), preservatives in cosmetics (parabens) and biomarkers (polycyclic aromatic hydrocarbons, pyrimidic bases). The analyses were conducted on model solutions and complex matrices (cosmetics, extraterrestrial analog samples). Flow catalytic reaction meant for the reduction of nitroarenes, the oxidation of aromatic alcohol, the carbon-carbon coupling and the sensitive detection of pesticides and synthesis intermediates (para-nitrophenol) have been achieved
Goueffon, Yann. "Étude et simulation des mécanismes de dégradation de revêtements anodiques noirs sur alliage d'aluminium pour applications en environnement spatial". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/643/.
Pełny tekst źródłaThermal exchanges between space vehicles and their environment are only radiative. A passive thermal regulation is possible using black inorganic coatings, prepared on aluminium alloys substrates, due to their thermo-optical properties (as>0,93; en>0,90). However, several cases of film flaking have been observed after thermal cycling performed to simulate the space environment. The goal of this work is the understanding of the anomaly causes, which could be a critical contamination source for the satellite. The process of black anodizing is composed of four main steps: pretreatments, sulphuric anodizing, inorganic colouring, and sealing. The influence of each step on the film's microstructure and composition has been studied. In particular, it has been shown that an increase of the anodizing temperature results in a drastic increase of the film porosity. Thermo-mechanical properties of these films (such as the Young modulus, residual stress, limit tensile stress or the coefficient of thermal expansion) have been experimentally determined. It has been proved that the colouring and sealing steps can lead to the crazing of highly porous anodic films. Adhesion evaluation (peel, scratch and four point bending tests) and a finite element model were used to identify the mechanisms of degradation during thermal cycling. Differential thermal expansions and dehydration of the film favour crack propagation inside the film and can lead to flaking
Graniel, tamayo Octavio. "Atomic layer deposition for biosensing applications". Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS071.
Pełny tekst źródłaAtomic layer deposition (gls{ald}) has emerged as an essential vapor deposition technique of thin films for countless applications. The rising demand for electronic components and nanostructured materials has established gls{ald} as one of the key fabrication processes in the nanotechnology market.In this work, novel nanostructured materials that can be used as transducers in biosensor devices are presented. These materials have been prepared by a combination of gls{ald} with top-down and bottom-up techniques such as nanosphere lithography (gls{nsl}), physical vapor deposition (gls{pvd}), metal-assisted chemical etching (gls{mace}), and electrodeposition.As a first promising candidate, silicon nanowires (gls{sinws}) covered with ZnO by gls{ald} were fabricated. These 3D structures are quite attractive for optical biosensing applications thanks to their intense photoluminescence (gls{pl}) activity at room temperature. As a first approach, these core/shell nanostructures were fully characterized and tested as possible sensors for the detection of hydrogen peroxide, which is a common reaction product of several oxidoreductases.In addition, Au-covered hollow urchin-like ZnO nanostructures were prepared with controlled size by combining NSL, gls{ald}, electrodeposition, and electron beam (gls{ebeam}) evaporation. The influence of the Au film thickness on the surface-enhanced Raman scattering (gls{sers}) capabilities of the substrates was investigated. The optimized structures were used to detect thiophenol molecules with a limit of detection (gls{lod}) of SI{e-8}{Molar}. Additionally, adenine can be detected with a concentration as low as SI{e-6}{Molar}. The excellent uniformity and batch-to-batch repeatability of the substrates makes them excellent candidates for reliable SERS sensing and biosensing.Moreover, a miscellaneous group of novel materials with enticing features that can be readily applied in sensing, catalysis, and plasmonics is presented. Bimetallic Pd/Au nanoparticles supported on gls{sinws} with gls{ald} and galvanic replacement were fabricated. Furthermore, hollow urchin-like ZnO structures with ZIF-8 via electrodeposition were fabricated for possible SERS applications
Al-Mohamadawi, Ali Abdullah Hassan. "Contribution à l'étude de l'impact de l'environnement vis-à-vis d'éco-matériaux lignocellulosiques". Electronic Thesis or Diss., Amiens, 2016. http://www.theses.fr/2016AMIE0040.
Pełny tekst źródłaDue to their low cost, lightness and thermal properties, lignocellulosic byproducts received a particular attention, in the recent years, for manufacturing lightweight concretes. However, these byproducts are not fully compatible with the cement matrix, leading to setting delay, significant dimensional variations, and low mechanical strengths of the composites elaborated. To avoid such drawbacks, a coating process of flax shives using different substances has been adopted in this study. It leads to a reduction in treated shive water absorption compared to raw shives. The composites obtained exhibit significant improvements in hydrous behavior and mechanical strengths with moderate increase in the apparent bulk density and thermal conductivity. The phenomena of moisture transfer in the produced composites can significantly influence the durability and performance of them. In fact most of the materials used in the building area are porous, containing water as vapor or liquid. Therefore the water vapour permeability, sorption isotherms and moisture buffering capacity have been determined. The results obtained show the good hygric performance of the eco-composites elaborated. Three leaching tests have been proposed in this study to identify the chemical speciation of the materials and to evaluate their releasing into the environment. The experimental conditions of the leaching tests have been chosen to simulate different states of our composites in external environments in service or end of life. The leaching behaviour of the cement-based products elaborated differs little according to flax shive treatment and the leaching of toxic substances has not been identified
Tlijani, Mohamed. "Contribution à la caractérisation thermophysique de matériaux bio-isolants : valorisation des déchets de bois de palmier". Electronic Thesis or Diss., Paris Est, 2016. http://www.theses.fr/2016PESC1157.
Pełny tekst źródłaThe growing interest in new concrete and their use in many fields of civil engineering was that we wanted to bring a new approach to the design of a new product consisting of a reinforced concrete with basel end frond palm fibers. This led us to conduct the experimental study of thermal properties of natural fibers of date palm (Phoenix dactylifera L.). The analysis of experimental results showed that the essential factors affecting the thermal conductivity are the variety of date palm and the fiber orientation and that the basel end of the frond palm is the most interesting part as thermal insulation. However, the main problem encountered when using plant fibers as reinforcement is cohesion, bonding with the matrix and dimensional instability so the composite loses its mechanical properties. In this context, an alkaline pretreatment of palm fibers was envisaged to clean and modify the fiber surface to address the problems of dimensional stability of the fibers and degradation before their use as reinforcement in the cement matrix. We also studied the influence of chemical treatment with sodium hydroxide on the mechanical properties of processed samples, they were subjected to the tensile test to estimate the fracture strength for each treatment concentration, the Young's modulus and elongation at break corresponding. Subsequently, we conducted experimental and theoretical research on the thermal conductivity of different formulations of basel end palm wood concrete composite. The study of the theoretical apparent thermal conductivity was based on an approach that relies on a process whereas the material consists of a solid matrix combined with a fluid phase (air). Finally, we performed a numerical simulation of heat transfer phenomena to assess the thermal conductivity of basel end frond palm concrete composite and validate subsequently the theoretical prediction model selected. The results showed that the numerical approach based on the isotropic orientation of the particles in the composite coincides and approaches the physical reality
Clair, Guillaume. "Etudes théorique et expérimentale des plasmas produits par laser en vue de leur application à l'analyse chimique des matériaux en environnement complexe". Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2011. http://tel.archives-ouvertes.fr/tel-00925927.
Pełny tekst źródłaClair, Guillaume. "Etudes théorique et expérimentale de plasmas produits par laser en vue de leur application a l'analyse chimique des matériaux en environnement complexe". Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22019/document.
Pełny tekst źródłaThis work provides an original study about laser-matter interaction in the nanosecond regime, based on a coupling between the experiments and the modelling. The experimental study provides a description of the dynamics of the laser produced plasmas. The modelling, based on a 1D numerical scheme, is aimed to describe the heating of the target by the laser pulse, the process of matter ablation and the formation of a plasma in this ablated material due to the interaction with the laser. The comparisons between both experimental and numerical results give the order of accuracy of the results obtained by modelling. These comparisons are limited to the first hundred nanoseconds of plasma expansion. We show that the plasma shielding, the plasma expansion and the propagation of the shockwave are well modelled. Furthermore, the values of both ablation and plasma formation threshold are accurately computed. However, many differences are observed in the results concerning the laser-target interaction process. Finally, the degree of accuracy of the model is sufficiently high to study precisely the background gas effet on both plasma dynamics and properties
Youssef, Alice. "Prise en compte des apports mécaniques du béton de chanvre pour le calcul de structure bois/béton de chanvre et métal/béton de chanvre". Electronic Thesis or Diss., Lorient, 2017. http://www.theses.fr/2017LORIS431.
Pełny tekst źródłaLime and hemp concrete (LHC) is nowadays the most developed bio-based aggregate building material in Europe. It consists of hemp shiv and mineral binder mixing with water. Generally, bio-based materials like LHC are used for their thermal insulation properties in building. Most blocks of Lime Hemp Concrete which have been studied, show a brittle behavior and a very low mechanical strength. The formulations are generally rich in binder and slightly compacted. Up to now, this material is then not considered as a load bearing material and is mainly used as filler insulation, combined with structure components made of wood, concrete or masonry. A study has tested other formulations, with higher contents of aggregates thanks to a compaction process, in order to improve both the rigidity and the strength of the hardened mixtures. In these formulations, shiv which has higher amount is definitely lighter and more porous than lime, which prevents a significant increase in thermal conductivity. The present work of my PhD is an experimental study of the compressive and shearing behavior of hemp concrete, in order to study the load-bearing capacity and bracing of this bio based material, while maintaining good qualities of thermal insulation in building. Two compacted formulations were tested M1 & M4, as well as samples obtained from trade-blocks Chanvribloc®. Two series of tests were performed. The first one is a uniaxial compression test in each direction for characterizing the mechanical anisotropy of the material. This anisotropy is induced by the compacting process. The second one permits to characterize the shearing behavior of the different mix-designs. In this study, an original shear device was developed, specifically designed for this kind of material, which allows shearing under controlled normal stress. An image processing performed was carried out, using a camera and ARAMIS image processing software during shear tests, to evaluate the fields of deformations and to study the behavior of the specimen during the shear test. The compressive experiments results have shown that this material is anisotropic, even when it is industrially molded by vibrations. The material has a transverse isotropic behavior. The behavior in the longitudinal direction is characterized by very high ductility, while the transverse behavior is very brittle, with a highly variable and unsteady behavior. The experimental results in shear show a high ductility of this material. These results are very promising, an interesting behavior of LHC walls in term of potential bracing. Numerical modeling and applications have been carried out to illustrate the use of hemp concrete blocks for bracing buildings. The formulation M4 exhibits a better behavior under moderate and average seismic actions, compared to the formulation M1, while the Chanvribloc walls in the present state do not allowthe buildings to be braced in moderate or medium seismic zones
Bouchenafa, Othmane. "Mécanosynthèse et matériaux de construction : optimisation et application pour la clinkérisation et la géopolymérisation". Electronic Thesis or Diss., Paris Est, 2019. http://www.theses.fr/2019PESC1003.
Pełny tekst źródłaConstruction materials are an essential need for humans. After Water, concrete is the most widely used material in the world and cement production is constantly increasing due to the increase in the world population. In 2010, the annual cement production reached 3.3 billion tonnes. An increase of +6.9% was recorded in 2015 for a production that reached 4.6 billion tonnesStudies conducted on the environmental impact of the clinker manufacturing process have revealed that for a production of one tonne of clinker, a quantity of 0.7 to 0.8 tonnes of CO2 is released into the atmosphere or an annual emission of 2.8 billion tonnes of CO2. These greenhouse gas emissions are responsible for 5% of global emissions. In order to reduce this impact, solutions already proposed such as the use of alternative fuels for clinker manufacture, the partial substitution of cement by industrial co-products or carbon capture and storage.This thesis is part of a desire to reduce the carbon impact in the manufacture of construction materials by introducing the mechanosynthesis process into the production process of clinker and cement as well as geopolymers.The thesis work has been divided into 3 main parts:The first part concerns the mechanosynthesis process optimization by adding process control agents (PCAs). The use of these agents for the grinding of fly ash and blast furnace slag has reduced the milling time to 15 minutes, whereas without PCA, 1 hour milling time is required, or even 3 hours for optimal milling. Cement pastes which we have substituted up to 50% clinker with industrial co-products activated by mechanosynthesis with PCAs (we have used alcohol and water) have shown higher mechanical performance than those prepared with 100% Portland cement.Cement pastes prepared with a substitution of 50% milled slag 15 min + 4% alcohol has shown an improvement in mechanical performance (compression) of + 10%, + 15% and + 40% compared to a reference cement paste for 7, 28 and 90 days respectively.The second part aims to propose a clinkerization process by indirect mechanosynthesis. We have used limestone and clay (traditional products for clinker manufacturing) to produce an equivalent clinker. To achieve our objective, we have used indirect mechanosynthesis, which consists of coupling a mechanical activation with short milling time and a heat treatment not exceeding 900°C. This technique has allowed us to produce the essential compounds of clinker, C3S alite (Ca3SiO5), β-C2S belite (Ca2SiO4) and C3A aluminates.The last part is focused on the direct mechanosynthesis process used for the production of a ready-to-use geopolymer powder only by adding water. This process consists of mixing aluminosilicates such as slag, fly ash or metakaolin with chemical activators by grinding to obtain a final geopolymer product.Geopolymer paste formulations have been made and encouraging results in terms of compressive strength have been obtained
Cazaux, David. "Mesure et contrôle in situ de la perméabilité des matériaux utilisés dans les dispositifs d'étanchéité pour la protection de l'environnement : état de l'art et développements". Lyon, INSA, 1998. http://www.theses.fr/1998ISAL0066.
Pełny tekst źródłaField permeability measurement of soils and materials used in containment system for protection of soils et groundwater is now a obligation in French regulation. These materials have a permeability generally Jess than 1. 10-6 m/s and need specific test methods. We distinguish traditionally two families that are shallow methods with ting infiltrometers and borehole methods more common for characterization of deeper materials. We wrote a State of the Art about the main methods used in France and abroad trying, with the help of comparative tests, to determinate their respective field of application and eventual restrictions. We propose a precise analysis of constant head test methods which was chosen for French standardization with the new apparatus we conceived from passed experiences. Experimental studies are performed on clayey soils which have different physical properties and permeability: silt, clay, sand bentonite mixtures, and also geosynthetic clay liners. Our work deal with an original analysis of infiltration data during the first hours of infiltration. We compare different unsaturated and saturated approach with the traditional methods. To manage short term tests to qualify soil liners, we propose some developments on the pressure pulse technique applied to boreholes. This method can lead to estimation of perm abilities less than 1. 10-9 m/s in a few hours what provide a great interest for permeability control during construction of soil liners
Ratovoson, Domoina. "Propriétés thermomécaniques de la peau et de son environnement direct". Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2011. http://tel.archives-ouvertes.fr/tel-00716268.
Pełny tekst źródłaMarchetti, Mario. "Aspects globaux et locaux de la mise en oeuvre de la lubrification fluide en ambiance spatiale". Lyon, INSA, 2000. http://theses.insa-lyon.fr/publication/2000ISAL0082/these.pdf.
Pełny tekst źródłaFluid lubrication is applied for space applications since the sixties. Physico-chemical and rheological properties of lubricants are adapted to such a severe environment. Nevertheless, several aspects have to get clear before a safer use of this lubrication technique. General first ones deal with cleaning procedures of metallic parts and with tribological and rheological behaviour of oils used for these extreme applications. Due to the environment (ultrahigh vacuum,. . . ), oil spreading, and the absence of maintenance, oil losses must be necessarily compensated. Techniques to continuously feed and to maintain enough lubricant to ensure long lifetime mission are employed in ball-bearings. Cleaning procedure has four objectives. They include the removal of contaminants harmful for fluid lubrication, a reproducible efficiency, continuity of the use of solvents and the respect of legislation. The combination of an alkaline solution and an azeotrope of hydrofluorocarbon-dichloroethylene allows to reach an acceptable contamination level and a good wettability of stainless steel. Numerous satellite mechanisms run at low speed. The most common lubrication regimes are so elastohydrodynamic and mixed. Two lubricants for aerospace applications have shown different behaviours. A linear perfluoropolyalkylether can create an elastohydrodynamic film, even at very low speed
Portier, Eric. "Lien entre environnement de dépôt et diagenèse précoce : importance dans la prédiction des qualités réservoir". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS548.
Pełny tekst źródłaReservoir quality distribution in subsurface, within an aquifer, storage or a hydrocarbon bearing reservoir, is largely variable and hence, difficult to predict. This study focuses on the early diagenetic processes, which are considered as key in the next steps of the diagenesis of deeply buried reservoir. Based on the examples of sandstones deposited in glacial setting during Ordovician of a gas field in Algeria and tidal sandstones from a Permian formation in Australia, the objective is to show the role and control exerted by the depositional environment on early diagenesis, and especially the major role of sediment reworking to predict reservoir quality distribution. The studied reworking processes are responsible of clay incorporation into sand deposits, as clay coats around detrital gains or as pore linings. The nature of clay is then determinant in the diagenetic processes, as these coatings may enhance chemical compaction if illitic in nature, or reversely, may inhibit cementation and help preserving reservoir quality if they are made of ferrous chlorite. These reworkings are associated to fluid overpressure within the sediment in glacial settings, whilst they are associated to the permanent reworking of sands by tidal currents, enabling the agglomeration of clay flocs to detrital grains with biofilm elements acting as natural glue
Ngoufo, donkeng Noëlle Edwige. "Vieillissement de matériaux hybrides composites biosourcés/métal sous sollicitations thermiques et hydriques. Application au développement de mobiliers urbains ultra légers et durables". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2021. http://www.theses.fr/2021UBFCK019.
Pełny tekst źródłaIn the perspectives of the future city, the progressive use of autonomous vehicles seems to become unavoidable. The preparation of an adequate framework for the deployment of this future mobility represents an important issue. This requires revisiting the urban infrastructures of cities from the choice of material to the design, and to propose solutions based on mobile street furniture. Faced with this challenge, hybrid materials such fibre metal laminates (FML) present interesting characteristics. FML made of plant fibre composites are of particular interest to minimize their environmental impact. Thus, the objective of this thesis is to design and manufacture plant-fibre metal laminates and assess their mechanical performance and durability in view of their use for street furniture.Two families of hybrid materials are studied, namely steel/flax-epoxy and steel/flax-polypropylene. For the steel/flax-epoxy hybrid material, the influence of some aspects such as the composite/metal assembly method, the lamination of the composite layers, and the structuring of the hybrid was evaluated on the mechanical performances using three-point bending and impact tests. The structuring of the hybrid is the most influential parameter on the measured properties. The results also show that the developed hybrid solutions have superior properties when compared to most of the mono-material solutions generally used for street furniture.Hybrid steel/flax-polypropylene and flax/polypropylene composites were subjected to accelerated hydrothermal and thermal ageing. Hydrothermal ageing leads to a drop in the flexural and impact properties of the composite, as well as a degradation of the latter. For the hybrid, a real drop was only observed in the flexural properties. The composite of the hybrid also degrades, but the phenomenon is attenuated by the presence of the metallic layers. Thermal ageing leads to yellowing and embrittlement of the composite by thermo-oxidation. This results in a significant drop in the bending properties and impact of the composite over the long term. At the hybrid level, the interface is severely affected by aging; the metal is delaminated after less than two days of aging
Sayagh, Shahinaz. "Approche multicritère de l'utilisation de matériaux alternatifs dans les chaussées". Phd thesis, Ecole Nationale des Ponts et Chaussées, 2007. http://tel.archives-ouvertes.fr/tel-00348412.
Pełny tekst źródłaPodesta, Laurie. "Etude expérimentale de la fissuration en fluage de l'acier 316H vieilli sous environnement CO2". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTS011/document.
Pełny tekst źródłaAt elevated temperature (550°C) in CO2 environment, intergranular creep cracks have been observed in thermally and environmentally aged 316H austenitic stainless steel. The objective of this work is to enhance the understanding of the creep crack mechanism and the effects of environment on crack initiation and growth. Some microtests on Single Edge Notched Tensile specimen (SENT) have been performed to better describe the interaction between chemistry and mechanics at the microstructural scale. A creep crack monitoring procedure using Digital Image Correlation (DIC) have been developped and assessed using Finite Element Modelling (FEM) of cracked bi-crystal. Based on a projection on Linear Elastic Fracture Mechanics expressions, the crack parameters (crack tip position, orientation) can be determined and the growth can be measured. A validation on in-situ tensile tests on SENT 316H specimen is proposed
Larippe, Laure. "Étude du comportement en fatigue des câbles d'acier sous environnement et chargement variables". Electronic Thesis or Diss., université Paris-Saclay, 2022. http://www.theses.fr/2022UPAST121.
Pełny tekst źródłaHeavy duty tyres are reinforced with steel cords to take up the stresses generated by the inflation pressure and the weight of the vehicle. The cable is an assembly of drawn wires helically wound in several layers. The mechanical behaviour of a cable is a function of its architecture as well as the material-processing possibilities available at the wire scale. In service, the cable is subjected to a complex combination of cyclic mechanical and chemical stresses leading to fatigue damage. To reduce the environmental impact, these cables are targeted by a lightweighting strategy, viable only at similar or better performance. A prerequisite for the introduction of new materials in a tyre is therefore the development of reliable models predicting the fatigue life of the cords, which implies an understanding of the fatigue mechanisms. For simplicity, the study was carried out at the unit wire scale (180 µm diameter).Different types of wires were produced by the manufacturer, varying the parameters that have an influence on fatigue. A tensile-tensile fatigue test under a controlled environment representative of the stress in service was developed. The material-process-environment parameters involved in crack initiation and propagation are identified by constructing Wöhler curves. In-situ crack propagation monitoring tests within the wire were performed in a controlled environment under synchrotron radiation for positive load ratios. The Paris laws and the parameters impacting them were obtained.All the experiments made it possible to identify the physical mechanisms involved and the corresponding parameters. A predictive model was developed at the wire scale. Based on the propagation of a distribution of surface defects, it estimates the life of the wire for a given mechanical and chemical stress
Matoiri, Chaibati Nadare. "Méthode probabiliste générique de qualification de la durabilité / fiabilité du béton dans son environnement". Thesis, Angers, 2020. http://www.theses.fr/2020ANGE0021.
Pełny tekst źródłaThe evolution of construction techniques, innovation and the environmental consideration standards are driving construction players to offer efficient and innovative materials for the construction of buildings and various infrastructures around the world. The material remains the most widely used in the construction industry today.Concrete standardization is generally based on prescriptive rules that take into account the Water/Cement ratio, the minimum resistance class, the minimum cement content, minimum air content, etc. This prescriptive method remains satisfactory but must be supplemented by another alternative to take into account the use of concrete composition not mentioned in the standard. Thus, the performance-based approach to concrete durability has been proposed. The aimis to allow the manufacture of concrete with a different formula than the standard while showing that it is as efficient as that of the standard. This performance demonstration involves the use of durability indicators and performance tests.The results of the tests carried out on the new concrete formulation will show whether its performance is equal to or above that of the standard. The problem arises in the number of tests to be carried out in order to guarantee the performance of the concrete. In this thesis, a generic method of qualifying the durability/Reliability of concrete with an optimized test plan is proposed for different types of environments. This method allows to estimate the durability/reliability of concrete in its environment with a given guarantee and a statistic of the tests to be carried out. The Wiener process is used to model degradation processes in concrete.An application of the method is carried out for the case of a concrete subject to carbonation
Ficheux, Maxime. "Diffusion multicomposante et environnement structural dans le verre Na2O-CaO-Al2O3-SiO2 contenant du zirconium". Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS429.
Pełny tekst źródłaZirconium is widely spread element on Earth and actually intensively used either in its oxide form (zirconia) or in its silicate oxide form (zircon). The main interest of zirconium is to improve thermomechanical properties. This element enters in the composition of refractory materials that are sintered or electro fused ceramics used for glass furnace structure. Zirconium may also enter in glass composition through two different possibilities: at high temperature, it may move from the wall of the furnace to the glass as contaminant or it can enter in the initial glass composition, for which it can increase chemical corrosion by strengthening glass chemical durability. The understanding of its incorporation to the silicate glass structure is the first research axis of this thesis. This axis is also interesting for geosciences where zircon dissolution in geological glasses like magmas have similar issues. This dissolution phenomenon of zircon or refractory directly depends on zirconium mobility from the crystal towards the glass. This mobility may be led by several mechanisms like convection or diffusion. We focused our researches on chemical diffusion determination. Several studies have already determined diffusion coefficient of zirconium in glasses. The innovation of this thesis is the determination of mobility trough multicomponent approach, considering that each element impacts the mobility of all others. Additionally, a structural study of zirconium environment is coupled with the mobility determination
Dieng, Mountakha. "Evaluation des contraintes thermomécaniques dans un packaging plastique pour l'environnement spatial". Limoges, 2014. http://www.theses.fr/2014LIMO4002.
Pełny tekst źródłaOrganics materials such as PCB and glob top are increasingly used in space equipment to reduce the cost and weight by replacing the micro and macros packaging with non-hermetic packaging. The work developed in this report deals with the thermo-mechanical stresses of packaging plastics in a space environment. In this context we interested on th study of materials, satellite environment and its associated stress. The multi-physics numerical tool, ANSYS allows predict the behavior of plastic packaging and identify new design rules. We worked on various structures, studied the stress more complex structures such as an LNA module with bonding wire of encapsulated in resin, and CSP packaging components. Finally, we set up a thermo-mechanical bench measurement which is able to measure the deflection of assembled materials using a camera and control software. These measurements allow the cross-validation with the simulation results
Fernandez, Laure. "Transposition en architecture des connaissances d'ingénierie environnementale et des savoirs relatifs au choix des matériaux". Thesis, Toulouse, INSA, 2010. http://www.theses.fr/2010ISAT0020/document.
Pełny tekst źródłaNowadays, environmental proceedings can use more and more methods and design tools to start with the conception. However, these technical methods turn out to be untapped into architectural projects. This question orientated our research towards environmental quality of materials and processes of implementation. Through the update of the knowledge and innovative methods, our work tends to increase the capacity of operational practice in architecture. The implementation of a design assistance tool - easy to use for non experts and providing several clearly configuration fields, based on caseworks and linked to quality of materials - is a significant evolution in architectural communities. We point up several innovative propositions for future design assistance tools. We illustrate it by the setting up of a prototype named MaTerre’iO. This mock up informs architectural designers about the knowledge upon materials, and more specifically on the environmental engineering knowledge.The main repercussion of our researched work is to contribute to initiate an innovating interface between environmental engineering topics and expectations of architectural design
Caboche, Juline. "Développement d’assemblages brasés céramique-métal à haute tenue en température dans un environnement agressif". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM076.
Pełny tekst źródłaAerospace technology developments are blooming. Since the 1960’s the Turbine Entry Temperature for aero-engines gas turbines keeps rising to improve their efficiency. Sensors working close to the combustion chamber are required in order to master the turbine performances. This results in an industrial urge to develop ceramic-to-metal assemblies able to endure severe engine environment (>1100°C under air, vibrations, etc.)The choice of an alumina as the ceramic part ensures a good insulation at high temperature. The main issue remains the metallic material which must be refractory, resistant to oxidation and affordable. The application of a ternary carbide (phase MAX) is tested. The braze alloy composition is adjusted to each system so as to provide a good ductility, thermal stability and a metallurgical matching as regards dissolution and brittle compounds formation.Braze alloys based on the Au-Pd-Pt system are investigated. The aforesaid liquidus and solidus surfaces are defined from experimental measures. Diffusion, dissolution and inter-granular penetration at the metal/braze alloy interface are described to suggest improvements. Aluminum diffusion from alumina-forming materials towards the braze alloy is the dominant phenomenon during brazing, despite the use of a diffusion barrier. The use of noble materials for the metallic substrate is mandatory.Geometrical and chemical assembly parameters are defined for selected brazed system based on the physicochemical interactions occurring during brazing and aging under air. The best brazed assemblies present an excellent hermeticity after brazing. Thermal cycling aging in severe conditions is detrimental to ceramic-braze alloy bonding, leading to interfacial cracks. Two promising strategies are suggested to ensure a reliable ceramic-to-braze alloy bonding during thermal cycling
Cheminet, Hélèna. "Élaboration de nouveaux revêtements de contrôle thermique pour applications spatiales". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14330.
Pełny tekst źródłaThis work presents the formulation and the study of polysiloxane resins and hybrid sol-gel materials to develop new protective coatings resistant to space environment. Spacecraft thermal control and polymer protection towards atomic oxygen are required in Low Earth Orbit applications. Besides the stability in the space environment and the process requirements, the coatings have to exhibit innovative properties (such as a low curing temperature) and be composed of raw materials with easy supply in order to avoid any risk of obsolescence
Rival, Guilhem. "Vieillissement sous irradiation électronique du PolyEtherEtherKetone : optimisation des propriétés électriques pour applications en environnement spatial". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30073.
Pełny tekst źródłaThis thesis is part of a research concerning the behaviour of polymers in space environment. It has two goals: to study the ageing of PolyEtherEtherKetone (PEEK) under electronic irradiation and to optimise its electrical properties in order to limit surface charge phenomena. For this purpose, PEEK/Short Carbon Fibre composites have been developed. The electrical percolation threshold of the fibres was determined at a volume content of 9 %. As space applications of PEEK require an electrical insulating behaviour, a filler content of 3 %vol was selected. The presence of the fibres improves electronic conductivity at room temperature, even below the electrical percolation threshold. Samples were then subjected to a high-energy electron beam to simulate their ageing in a space environment. Analysis of the irradiated samples revealed two simultaneous ageing phenomena: cross-linking of the amorphous phase and amorphisation of the crystalline phase. Irradiation near the glass transition (165 °C) leads to a higher cross-linking density due to a higher recombination rate of radicals. In composites, fibres limit amorphisation and stabilise the mechanical behaviour evolution. With regard to the electrical properties, ageing induces a decrease in ionic conductivity above Tg. In composites, this decrease is amplified. At room temperature, irradiation at 25 °C and at 165 °C leads to opposite evolutions in electronic transport which are associated with competition between cross-linking and amorphisation. In composites, fibres stabilize the evolution of potential relaxation and always allow a faster flow of electrons
Nguyen, Thanh Binh. "Valorisation des sédiments de dragage traités par le procédé NOVOSOL(R) dans des matériaux d'assises de chaussée : comportement mécanique et environnemental". Toulouse 3, 2008. http://thesesups.ups-tlse.fr/704/.
Pełny tekst źródłaThe management of dredged sediments is a challenge for our society because of their huge volume. The contamination of heavy metals and organic micro pollutants make that the majority of dredged sediments are regarded as dangerous waste and are put in discharge. This isn't in the same point of view of the durable development policy: the French law supports the valorization so that only ultimate waste is put in discharge. In this context, Solvay Company has developed the process NOVOSOL(r) for the treatment of the dredged sediments polluted. The process comprises two stages: an immobilization of heavy metals by formation of apatite under a phosphatising reaction with acid phosphoric and a destruction of the organic matter by a calcination. The goal of this thesis is to use river sediments treated by the process NOVOSOL(r) in road base materials. Experimental studies in laboratory comprise two aspects: mechanical performance and leaching behaviour. The treated sediments by NOVOSOL(r) are introduced into road base mixes treated with cementitious binders as substitute for regular sand. The preparation of materials according to the normalized methodology in laboratory does not present any difficulty. As the treated sediments content increases, the water demand increases and the materials are less compact than reference material. This is due to the characteristics of treated sediments: important ratio of fines, friability and the porosity of granular. These characteristics have as a consequence to weaken the granular skeleton, which results in a reduction in the stiffness module of materials. On the other side, the reactivity of treated sediments NOVOSOL(r) in the matrix of cimentitious binder and a better homogeneity of materials lead to an improvement of the tensile strength. Mechanical performance of all the materials with of treated sediments NOVOSOL(r) evaluated by index of elastic quality is better than that of the reference material. .
Tornay, Nathalie. "Vers des outils d'aide à la conception pour intégrer les dimensions techniques, écologiques et sensibles des matériaux de construction". Electronic Thesis or Diss., Toulouse, INSA, 2011. http://www.theses.fr/2011ISAT0003.
Pełny tekst źródłaThe choice of materials and way of implementation is known and will be known as a significant growth in the world of architecture. Actually, changes are largely induced by technical dimension, but also representations and precepts that appear with the emergence of the concept of sustainable development in our society.Design support tools about materials scale focus on the physical dimensions (thermal, life cycle, refreshments, etc.). Our work is questioning the integration of technical, environmental and sensible dimensions in a design support tool based on reference. The referential activity is a specific approach in the initial phases of designing on a project. These phases correspond to crucial choice, which remain poorly assisted by digital tools.Our work aims to highlight the different characteristics of materials, but also their interactions. This study differs from conventional approaches of materials, which generally, constructive solutions are presented material by material. Indeed, we rely on a data structure and interdisciplinary knowledge (architecture, urbanism, landscape, aesthetic, technical, cognitive, perception approach, environmental approach, etc.).This research tends to be a first proposal for a design support tool named DILEM'MAtériaux that takes into account materials in their contribution to origin of founding ideas and definition of concept, in the initial phases of designing on a project
Rioland, Guillaume. "Elaboration de matériaux zéolithiques pour la décontamination moléculaire en orbite". Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH9333/document.
Pełny tekst źródłaIn low earth orbit, global performances of satellites can be affected by the contamination of critical surfaces as optical devices and detectors. On-orbit molecular contamination is due to outgassed organic pollutants emanating from spacecraft materials. One way to reduce and to eliminate this phenomenon is the use of molecular adsorbents. Among them, zeolites appear to be relevant materials for contaminants retaining. Unlike common powder materials, zeolites films can also avoid the secondary dust contamination due to particles breeding and can be easily inserted in the satellite structure. As a consequence, this work deals with the shaping of zeolitic powder.Three shapes were developed during this work: pellets, beads and paints. Zeolitic pellets showed very interesting mechanical properties, on the contrary to zeolitic beads which can beget a particulate contamination (vibrations). The adsorption capacities of these two shapes are good: molecules such as n-hexane, cyclohexane and 3-methylpentane were adsorbed. Finally, the first formulation of a zeolitic paint was developed: a loss of 20 % of the adsorption capacities was observed (presence of binder). The adhesion (ISO 2409 test) was acceptable. This last shape is one of the many perspectives of this work
Blanck, Gaëtan. "Utilisation de produits non traditionnels pour le traitement des matériaux de terrassement : impact sur les propriétés géotechniques et bilan environnemental". Electronic Thesis or Diss., Université de Lorraine, 2013. http://www.theses.fr/2013LORR0126.
Pełny tekst źródłaSustainable development principles lead earthworks companies to use all natural materials and to reduce the environmental impact of their activities. In this context, the use of industrial organic products derived from the processing of renewable matter has been proposed. In this study, three non traditional products have been selected: an enzymatic solution, a lignosulfonate and an acid solution. In a first approach, hydromechanical properties of four treated soils (a silt, a clayey soil and two sands) were investigated. The experimental results showed interesting applications for the silt when its natural water content is low. Indeed, the compaction ability of the soil was increased after enzymatic and lignosulfonate treatments. Thus, savings of water and energy could be expected during the construction stage. To gain a better understanding of the mechanisms of the treatment products, the microstructure of treated soil were investigated with scanning electron microscopy, mercury injection porosity and was completed by the study of a surfactant addition in soils. The global aim of the study was beyond the characterization of mechanical behavior of treated soils, therefore, environmental balance was also estimated for the different applications defined in accordance to the experimental results. For enzymatic and lignosulfonate treatments, a comparison of the global environmental impact was done thanks to a life cycle assessment methodology. This approach showed that technical and environmental interest are associated for the compaction of dry soils when the production and transport steps have limited environmental impact as demonstrated in the sensitivity analysis