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Sangely, Matthieu. "Dégradation biologique des polychlorobiphényles". Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0094/document.
Pełny tekst źródłaSoil is a complex interface between all compartments of the environment. Their pollution contributes to the spread of many pollutants. PCBs are persistent toxic compounds in the environment. Widely used especially in dielectric oils, they now contaminate many industrial floors. Heat treatment of these soils is very expensive and can cause the emission of dioxins. The objective of this work is to study a biological treatment process for the degradation of PCBs in soils. Biological degradation of PCBs has been observed in the presence of two cultured organisms, Burkholderia xenovorans and Phanerochaete chrysosporium, confirming their technological potential under aerobic conditions. Under anaerobic conditions, a microbial community with the ability to degrade PCBs was developed. A study of the diversity of 16S rDNA gene within this community has identified the species in this community. An analysis of life cycle assess the environmental performance of two methods for treating soils contaminated with PCBs, one thermal and one biological. This analysis quantifies the environmental benefit of the biological process compared with the heat treatment
Boutin, Olivier. "Analyse des processus primaires de dégradation thermochimique de la biomasse". Vandoeuvre-les-Nancy, INPL, 1999. http://docnum.univ-lorraine.fr/public/INPL_T_1999_BOUTIN_O.pdf.
Pełny tekst źródłaThe primary processes of thermal degradation of biomass are studied. A bibliographical research reveals the knowledge and the deficiencies on this subject. Fast pyrolysis of cellulose pellets are carried out in an image furnace and in a solar fumace. These original experimental deviees using a concentrated radiation deliver high and clean flux densities during controled irradiance times. Ali the products of the reaction are collected and analysed by liquid and gas phase chomatography. Mass and C, H and O balances are very good. The evolution of the products composition (liquid, volatile, gas and char) are examined as a function of the irradiance time and flux density. An intermediate liquid (at the reaction temperatures) species is observed. It is directly produced from cellulose partial depolymerisation. It mainly contains anhydrooligosacharides with degrees of polymerisation ranging from two to seven. The condensable products contain few compounds, unlike the bio ails usually obtained in fast pyrolysis. Gases are formed by secondary crakings of the vapors. Lt is possible to obtain only liquids and gases beyond a given flux density. The modeling of heat transfers (pellets and small particules) associated with the kinetics of decomposition is made. Ln most of the cases the agreement between theory and experiments is very good. The comparison between the results of this work and those usually obtained in classical fast pyrolysis is examined on the basis of the elementary processes of heat transfers
Contreras-Dominguez, Monica. "Dégradation de tanins condensés par des champignons filamenteux : analyse structurelle et enzymatique". Aix-Marseille 1, 2007. http://www.theses.fr/2007AIX11035.
Pełny tekst źródłaGousseau, William. "Pronostic de dégradation d'endommagements de roulements sur application aéronautique par analyse vibratoire". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI063.
Pełny tekst źródłaAs part of preventive maintenance of its engines, Safran Aircraft Engines wishes to complete its diagnostic operations with a reliable prognosis of the residual life of the bearings. Following an attack, there is currently a great deal of uncertainty about the remaining life before bearing failure from the threshold of vibrational observability of the damage. Current algorithms diagnose an approximate stage of degradation and generate alarm messages of different levels, each level corresponding to a different stage of degradation, combining confidence and severity of diagnosis. An important aspect of the prognosis is the taking into account of the contextual parameters influencing the rate of degradation. The objectives of this thesis are to have methods and tools to quantify a running time remaining before bearing failure with regard to: - the severity of the damage detected, - the environmental conditions of operation, - the depth The industrial constraints associated with these objectives are as follows: 1) The prognosis should be based, at least, on high-frequency vibratory measurements of a few kHz (accelerometers), contextual data (the rotational speeds of the different rotors, for example, or the amplitudes of the levels piloted on them), rotation regimes, revealing a loading of the bearings) 2). Constituing a database of tests resulting from a plan of experiments: these tests will have to take into account the constraints related to the control of the parameters considered to be significantly influential 3) This database must take into account the representativity of the vibratory environment of an aircraft engine. 4) Propose a tool or method of prognosis taking into account the nature of the bearing to consider
Blond, Eric Henri. "Dégradation thermomécanique des réfractaires au contact de laitiers sidérurgiques". Cachan, Ecole normale supérieure, 2003. https://tel.archives-ouvertes.fr/tel-00370776.
Pełny tekst źródłaDoukhan, Giuliana Nathalie. "Étude expérimentale et analyse thermochimique de la dégradation d'alliages pour surchauffeurs d'incinérateurs d'ordures ménagères". Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-337.pdf.
Pełny tekst źródłaGérard, Corinne. "Dégradation oxydante de la nicotine sur zéolithe de métal supporté ou échangé". Le Havre, 1994. http://www.theses.fr/1994LEHA0010.
Pełny tekst źródłaCarillo, Serge. "Dégradation des facteurs de transcription nucléaires FOS et JUN". Montpellier 2, 1994. http://www.theses.fr/1994MON20235.
Pełny tekst źródłaGrégoire, Laurie-Anne. "Analyse de profils de chaussées : effet du gel saisonnier et de la dégradation du pergélisol". Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27218.
Pełny tekst źródłaMethods adapted to road condition are needed to maintain and rehabilitate roads built on permafrost or in context of seasonal frost. Several issues can lead to increase repair and maintenance costs, decrease the pavement’s lifetime and increase problems related to the safety of road users. The project objective is to develop a profile analysis tool, which would help to locate thaw and frost sensitive zones, diagnose the causes of degradation and select proper mitigation strategies. The research project is divided into two parts. The first section is related to frost heaves on pavements in context of seasonal frost. Currently, there are diagnosis methods for detecting areas where frost susceptibility is present. These methods do not allow to determine whether the freezing problem is under or at the surface of the road; in other words if the problem is related to differential heave or uplift cracks. Moreover, the methods used are not adapted to municipal roads. According to the known problems of some sites, it was possible to develop a chart used to differentiate if the frost problem is in surface layers or deep in the road subgrade. Then, a 3D analysis was done to complement the chart. Using this technology, a new method will be developed to detect freezing problems through the transverse profiles. The second part focuses on the pavements built on permafrost. Current methods for detecting the degradation of permafrost under roads are unclear and need to be refined. Three test sites were studied on the Alaska Highway in Yukon. Depending on various analysis, such as analysis of longitudinal profiles, the spectral density and wavelength, trends analysis were found to characterize the instability of permafrost.
Léoni, Eric. "Modélisation dynamique des systèmes thermochimiques : réactions en phase liquide-dégradation thermique d'un combustible végétal". Corte, 2002. http://www.theses.fr/2002CORT2010.
Pełny tekst źródłaMallat, Amjad. "Phénomènes de dégradation des ouvrages anciens, techniques et matériaux de réhabilitation". Châtenay-Malabry, Ecole centrale de Paris, 2008. http://www.theses.fr/2008ECAP1111.
Pełny tekst źródłaJafar, Raed. "Modélisation de la dégradation des réseaux d'eau en vue d'une gestion prévisionnelle". Lille 1, 2006. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2006/50376_2006_132.pdf.
Pełny tekst źródłaAmiot-Carlin, Marie-Josèphe. "Dégradation de l'oleuropéine de l'olive (Olea europaea L. ) : aspects physiologiques, chimiques et technologiques". Montpellier 2, 1986. http://www.theses.fr/1986MON20155.
Pełny tekst źródłaBen, Ismail Nizar. "Etude des mécanismes radicalaires et ioniques lors de la dégradation thermique du polystyrène". Nancy 1, 1999. http://www.theses.fr/1999NAN10278.
Pełny tekst źródłaReverte, Cédric. "Stratégie expérimentale pour la détermination de modèles stoechio-cinétiques des réactions de dégradation thermique". Phd thesis, Toulouse, INPT, 2007. http://oatao.univ-toulouse.fr/7574/1/reverte.pdf.
Pełny tekst źródłaPrulho, Romain. "Analyse multi-échelle de la dégradation de membranes polymères d'ultrafiltration au contact de l'hypochlorite de sodium". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00866935.
Pełny tekst źródłaBoinsk, Frédéric Romuald. "Analyse et caractérisation d'une silice soumise à un processus de dégradation chimique : approche ponctuelle et locale". Mulhouse, 2007. https://www.learning-center.uha.fr/opac/resource/analyse-et-caracterisation-dune-silice-soumise-a-un-processus-de-degradation-chimique-approche-ponct/BUS4081234.
Pełny tekst źródłaThese works are based on the study of the structural behaviour of a heterogeneous reactive silica resulting from a natural siliceous aggregate (flint) submitted to a physico-chemical degradation process: the Alkali Silica Reaction. The impact of the reaction on the aggregate depends punctually of the degree of heterogeneousness of the structure; therefore, the appeal to the techniques of punctual analysis is then necessary. So, all the stages of the degradation of the silica on a grain of some microns were realized due to the use of the microbeam of the line LUCIA on SLS. The study of the behaviour of elements calcium and potassium in the structure of the aggregate was realized by EDX and consolidated by the analysis of the atomic environments of the silicon and cations by the interpretation of X-Ray absorption spectrums (XANES). These studies allowed to advance in the understanding of reactions mechanisms involved during ASR
Devynck, Pascal. "Dégradation de composés organiques volatils chlorés dans des flammes de méthane : analyse expérimentale et modélisation cinétique". Lille 1, 1997. http://www.theses.fr/1997LIL10121.
Pełny tekst źródłaRoy, François. "Caractérisation des transistors couches minces à base de silicium amorphe hydrogéné : analyse des processus de dégradation". Paris 11, 1986. http://www.theses.fr/1986PA112267.
Pełny tekst źródłaVan, Der Sypt Paul. "Analyse et modélisation des chemins d'efforts et de la dégradation des assemblages de type HYPER joints". Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0015.
Pełny tekst źródłaStructures need to cope with specifications displaying a rising complexity. Cost and mass budget reduction is no more an option. Optimization of structures occurs through innovative solutions for metal / composite assemblies. The current work focus on a new technology: the HYPER joints. Pins are manufactured on the top of a metallic part using additive manufacturing and then inserted inside a composite laminate while it is still uncured. From an industrial view, designers must be able to determinate the adequate pin pattern on the overlap surface to deal with the mechanical properties required. This work aims to propose a model predicting the failure load and the associated failure mode. To build such tool, a numerical / experimental dialog has been set up. A finite element model is established modeling the failure modes experimentally observed: pin failure and composite failure by ignition and propagation of delamination. Pin failure mode is investigated through three steps: material characterization, pin geometry analysis and finally the implementation of the finite element model integrating an elasto-plastic law. Delamination failure mode is analyzed thanks to cohesive zone modelling (CZM). Under pull-off loading, interface properties are identified using a model based on the linear fracture mechanic. Domain of validity is discussed through two study cases: a mixed mode loading combining pull-off and shear, and a configuration providing a complex load distribution between the pins. Finally, design tools were generated using the finite element model. Those tools are formed by reference curve allowing predicting the failure load and failure mode regarding the pin density and pattern chosen
De, Almeida André. "Propriétés mécaniques et dégradation des élastomères EPDM chargés ATH". Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0053/document.
Pełny tekst źródłaEPDM (EThylene Propylene Diene Monomer) are used as insulation for electrical cables in nuclear plants. Because of the radiative environment, the degradation of these cables is accelerated and a strong industrial challenge consists in the prediction of the cables lifetime. To address this crucial industrial concern, we first looked into the influence of the chemical composition of EPDM on their kinetics of degradation. To do so, two EPDM with different chemical compositions have been irradiated under radiations and in the presence of oxygen. The soluble fraction and the active chain density have been monitored as a function of the irradiation dose, and revealed the degradation by cross-linking and chain scissions. Furthermore, the kinetics of these mechanisms have been estimated based on statistical models: the cross-linking kinetics depends on the residual ENB content while the chain scission kinetics vary neither with the chemical composition nor the initial cross-linking degree. Moreover, beyond an irradiation dose, the cross-links are progressively broken. The mechanical performances were then studied at 80°C to prevent crystallinity. If the irradiation induces a decrease of the stress at break, the materials show an increase of the strain at break conversely to the EPDM systems studied by Planès et al. The mechanical properties of notched samples have then been employed in order prevent heterogeneities driven crack initiation. The tearing energy measured was correlated with the failure energy of notched samples andcan be described by the Lake and Thomas model with account for the real length between cross-links. The same study has then been performed at 25°C where the properties at break are seen to improve. Such improvements despite irradiation confirm that crystallites attenuate the degradation. This effect is more pronounced for the current set of materials because of a strong chemi-crystallisation. The addition of ATH fillers has been studied as well, showing an acceleration of the matrix degradation with the specific surface of the fillers. The understanding of the mechanical properties at break of filled materials seems complex because the failure can be obtained by various competing processes. Nevertheless, the matrix chemical nature can be mentioned as an important factor since the difference between the matrix mechanical properties and the matrix-filler interface properties will trigger the creation of macro-defects at the origin of failure. As for the neat matrix, the evolution of the composites mechanical properties tested at 25°C depends on the evolutions of both the crystallinity and the amorphous phase. More generally, this work questions the relevance of the actual lifetime criterion used in the industry. The energies at break are more directly correlated to the microstructural parameters and thus could correspond to a relevant criteria for predicting these systems lifetime
Revil, Narcisse. "Caractérisation et analyse de la dégradation induite par porteurs chauds dans les transistors MOS submicroniques et mésoscopiques". Grenoble INPG, 1993. http://www.theses.fr/1993INPG0098.
Pełny tekst źródłaPayre, Sébastien. "Analyse du stress dysfonctionnel au travers de la dégradation de la performance socio-économique des moyennes entreprises". Lyon 3, 2007. http://www.theses.fr/2007LYO33047.
Pełny tekst źródłaThe sharp increase in the number of illnesses could be attributed in part to the problems of stress that medical studies have increasingly forward, and which particularly concerns as we demonstrate the medium-sized enterprises. Through the analysis of this phenomenon, we try to overcome the traditional approaches to health and safety at work for a comprehensive approach that integrates ail of the socio-economic performance of enterprises. Ln the first part, we are positioning research on SMEs before define Medium Enterprises and describe the structural characteristics of their environment that will enhance the development of stress in their midst. Then we look at the theoretical approaches of this phenomenon before construct a dysfunctional definition. We based on a content analysis of sentences collected during interviews conducted in thirty enterprises and organizations. We characterize in the second part, the deterioration of the social performance and economic performance through three cases of medium enterprises. This deterioration leads to a lack of professionalism of the actors through the low quality of industrial relations and monitoring activities and men. We show that this situation generates conflicts that cause dysfunctional stress. Finally, we present a process of change tailored to the problem of dysfunctional stress to improve the functioning of the medium¬sized enterprises
Ruyffelaere, Fanny. "Etude mécanistique et cinétique de la dégradation oxydante des molécules parfumantes". Lille 1, 2005. http://www.theses.fr/2005LIL10154.
Pełny tekst źródłaPerfumes degradation is a problem of major concern in the perfumery industry because it is responsible for the loss of the odoriferous properties. The aim of this study was to identify the main chemical and photochemical processes, which result in the oxidative degradation of perfumed molecules. The first part was dedicated to the determination of the reactivity of perfumed molecules towards singlet oxygen(1O2) by measuring their global reactivity constants (kr + kq) by resorting to flash photolysis. The photosensitizing properties of dyes commonly used in perfumed composition were also assessed. The second part focuses on the interest of the oxidation potential as an oxidability index for the perfumed molecules. The third part deals with the elucidation of the aldehydes degradation mechanism in a silicone based complex matrix. The last part aimed at determining the antioxidant properties of phenolic perfumed molecules
Del, Vecchio Pamela. "Étude de la dégradation et analyse de défaillance de diodes laser de puissance spatialement monomodes émettant à 980nm". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0140.
Pełny tekst źródłaThis study addresses InGaAs / AlGaAs / GaAs laser diode emitting at 980 nm in bare chip configuration (COS-Component on Submount) for optical pumping in Er3+ doped fiber amplifiers. These devices have a level of technological maturity that the changes in the parameters observed during aging do not present sufficiently significant variations in order to obtain exhaustive conclusions in terms of reliability. Searching for alternative and/or complementary methods to the so-called « classical » methods aimed to understanding the failure mechanisms and the identification of signatures indicating possible future degradation of the laser diodes, represents today a strategic challenge for the current components. In this context, this study suggests a set of techniques based on the discrimination of the operation mode of the diodes in direct bias and in particular in reverse bias by electrical spectroscopy. The correlation of the different measurements in reverse bias, not more studied in the characterization of laser diodes, can reveal atypical behaviors highlighting presence of residual point defects in the volume of a diode because the currents observed are very weak. The reverse bias makes it possible to offer interesting perspectives considering that, this operation mode remains today almost unexplored for optoelectronic emitting devices such as laser diodes
Effendi, R.-Riesdam. "Analyse des mécanismes de dégradation en compression des composites unidirectionnels fibres de carbone-matrice organique et modélisation associée". Toulouse, ENSAE, 1993. http://www.theses.fr/1993ESAE0007.
Pełny tekst źródłaZurek, Antoine. "Problèmes à interface mobile pour la dégradation de matériaux et la croissance de biofilms : analyse numérique et modélisation". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I044/document.
Pełny tekst źródłaThis thesis deals with the numerical and mathematical study of models with free boundaries coming from physics and biology. In the first part, we consider a model which describes the carbonnation phenomena in reinforced concrete. The model involves a system of 1D-parabolic equation of reaction diffusion type defined on a domain with a moving boundary. The motion of this interface is governed by an ordinary differential equation and it increases asymptotically as a square root of t for large times. We first introduce a Finite Volume numerical scheme for the model with implicit/explicit time discretization and we prove its convergence. Next, we build a fully implicit scheme for which we are able to establish the behavior in square root of t of the interface in this discrete setting. In a second part, we study a cross-diffusion system modeling the expansion of some biofilms. We introduce a numerical scheme of Finite Volumes type which preserves the gradient flow structure of the model. We establish the existence of solutions to the scheme and its convergence towards a solution to the original model. Eventually, we consider a toy model derived from a more complete model called DPCM (Diffusion-Poisson-Coupled-Model). The later describes the corrosion of (nuclear waste) containers made of iron and stored in clay soil. Again the model involves a free boundary whose position is part of the unknowns. Using tools from Optimal Transport Theory and Calculus of Variations, we establish the existence of a solution to the model. This is a first step towards the study of DPCM for which no such result is availiable
Pellegrin, Bastien. "Analyse multi-échelle de la dégradation de membranes d'ultrafiltration en polyethersulfone - poly(N-vinyl pyrrolidone) en conditions d'usage". Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2084/.
Pełny tekst źródłaMotivated by drinking water production plants reporting membrane failure issues, this study investigates the ageing of a commercially available PES / PVP UF hollow fiber. Proof is given that membrane degradation is mainly induced by sodium hypochlorite exposure. The effects on the PES chemical structure are limited, very low extend of chain scission occurs and the formation of an ortho-substituted phenol is observed as the main modification. Experiments show that the presence of PVP and/or PVP degradation products is a required condition for the PES oxidation to occur. On the other hand, PVP appears to be very sensitive to hypochlorite exposure. PVP radical oxidation mechanisms are identified presenting a maximal reaction rate for neutral to slightly basic pH and leading to the partial removal of the PVP degradation products from the membrane structure. Correlation of macroscopic and molecular characterizations demonstrates that PVP degradation is responsible for the membrane integrity loss (impairing selectivity and mechanical performance), while hypochlorite exposure also induces enhanced membrane / solutes interactions, leading to an accentuated fouling. The representativeness of static continuous hypochlorite exposure regarding the actual on-site membrane ageing is confirmed by the analysis of membranes extracted from an industrially operated module. Nevertheless, the hypochlorite dose parameter, widely used in the literature, is demonstrated to be inappropriate to describe the degradation rate: the hypochlorite concentration impact is shown to be dominating the exposure time impact on the degradation rate
Jacquet, Pauline. "Amélioration d'une enzyme hyperthermostable pour la dégradation des organophosphorés". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0618/document.
Pełny tekst źródłaOrganophosphates (OPs) are neurotoxic compounds widely used as pesticides. Over the years, utilization of OP led to a considerable environmental contamination of soils and agricultural wastewaters, this pollution is furthermore a major health issue as these insecticides can be found in food. OP are highly toxic and are responsible for 300,000 deaths in the world every year. OPs were also developed as chemical warfare nerve agents such as sarin. Currently, no satisfying method for external decontamination is available, therefore bioremediation with enzymes is highly appealing. Among OP degrading enzymes, phosphotriesterases (PTEs) are the most active biocatalysts but are poorly stable what hinders their potential for bioremediation. Hyperthermostable enzymes from extreme environments were thus considered to circumvent this limitation. In particular, SsoPox isolated from the archaeon Sulfolobus solfataricus, displaying a lactonase activity and a promiscuous phosphotriesterase activity was deeply investigated. SsoPox is extremely robust but its activity for OP degradation is from far lower. A protein engineering strategy was started in order to reach a compromise between PTE activity and SsoPox robustness. Using structural similarities between PTEs and SsoPox, a mutational database was designed in order to transfer the highly performant active site of PTE into the hyperstable scaffold of SsoPox. This strategy led to variants displaying up to 2,000-fold increase against OPs as compared to wild-type enzyme. The variants efficiency was demonstrated in vivo using an original animal model planarian, allowed to enhance survival rate as well as mobility and regeneration capacity
Wong, Quai Lam Mary Sarah-Jane. "Assemblage et dégradation des parois de maïs : de la plante entière à l'échelle cellulaire". Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1406/.
Pełny tekst źródłaMaize is one of the most widely grown crops in the world and is grown for grain for human consumption, feedstock for cattle and more recently biofuel. When used as fuel, the most important agronomic trait is digestibility which is dictated by cell wall composition and structure. Many studies have been undertaken in order to improve cell wall digestibility and have essentially focused on the lignin biosynthetic pathway. During my PhD research, we have shown that a mutation in ZmCCR1 (Cinnamoyl-CoA reductase 1), key enzyme in lignin biosynthesis, modified lignin structure which in turn resulted in an increase in digestibility. Beyond lignification per se, my studies focused on the identification of other potential parameters influencing digestibility at the cellular level. This is especially pertinent in maize since its stem biomass is made up of different several lignified tissues and cell types. By combining cell wall biochemistry on laser microdissected (LMD) lignified tissues, with histological studies, we have been able to show that in highly contrasting lines (Cm484 and F98902) the lignified cell types patterning and in particular, the amount and cell wall composition are critical factors in determining maize digestibility
Limam, Emna. "Étude des mécanismes de dégradation de couches minces d'argent protégées par un revêtement d’oxyde". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066757.
Pełny tekst źródłaBecause of his unique optical properties, silver is more and more used in satellite mirrors, in particular for earth observation missions. Because of silver instability, a protective layer is necessary. Nevertheless, major defects (sulfidation points) observed during qualification and storage phases still raise the question of mirrors durability, particularly given that they are often stored for 10 to 15 years after satellite assembly. Our study focused on the space mirrors degradation, more specifically on the degradation of silver layers protected by oxide films () in the presence of sulfur components. Accelerated ageing in the presence of sulfur (gaseous or ions) manifests itself by sulfidation points growing from the silver layer through the protective layer defects, thus forming silver sulfide columns. The growth rate of these sulfide columns is fast at the beginning then slower and is accelerated by temperature and pressure. Degradation in solution () is markedly faster than in gas (). Moreover, the substrate surface morphology influences strongly the stability. Mirrors optical performances are markedly impacted by sulfidation. Mirror degradations were correlated to optical performances losses. The study of the non-accelerated ageing highlighted the major role of humidity in the silver layer degradation, involving layers delamination and protective layer cracking. As a consequence, the silver layer sulfidation is accelerated. On the basis of our results, a mirror degradation mechanism is proposed. Finally, a qualification test of the stability of mirrors against sulfidation was proposed
Kieu, Van Cuong. "Modèle de dégradation d’images de documents anciens pour la génération de données semi-synthétiques". Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS029/document.
Pełny tekst źródłaIn the last two decades, the increase in document image digitization projects results in scientific effervescence for conceiving document image processing and analysis algorithms (handwritten recognition, structure document analysis, spotting and indexing / retrieval graphical elements, etc.). A number of successful algorithms are based on learning (supervised, semi-supervised or unsupervised). In order to train such algorithms and to compare their performances, the scientific community on document image analysis needs many publicly available annotated document image databases. Their contents must be exhaustive enough to be representative of the possible variations in the documents to process / analyze. To create real document image databases, one needs an automatic or a manual annotation process. The performance of an automatic annotation process is proportional to the quality and completeness of these databases, and therefore annotation remains largely manual. Regarding the manual process, it is complicated, subjective, and tedious. To overcome such difficulties, several crowd-sourcing initiatives have been proposed, and some of them being modelled as a game to be more attractive. Such processes reduce significantly the price andsubjectivity of annotation, but difficulties still exist. For example, transcription and textline alignment have to be carried out manually. Since the 1990s, alternative document image generation approaches have been proposed including in generating semi-synthetic document images mimicking real ones. Semi-synthetic document image generation allows creating rapidly and cheaply benchmarking databases for evaluating the performances and trainingdocument processing and analysis algorithms. In the context of the project DIGIDOC (Document Image diGitisation with Interactive DescriptiOn Capability) funded by ANR (Agence Nationale de la Recherche), we focus on semi-synthetic document image generation adapted to ancient documents. First, we investigate new degradation models or adapt existing degradation models to ancient documents such as bleed-through model, distortion model, character degradation model, etc. Second, we apply such degradation models to generate semi-synthetic document image databases for performance evaluation (e.g the competition ICDAR2013, GREC2013) or for performance improvement (by re-training a handwritten recognition system, a segmentation system, and a binarisation system). This research work raises many collaboration opportunities with other researchers to share our experimental results with our scientific community. This collaborative work also helps us to validate our degradation models and to prove the efficiency of semi-synthetic document images for performance evaluation and re-training
Barré, Jean-Baptiste. "Évaluation du niveau de dégradation du bois dans les ouvrages de protection par spectroscopie proche infrarouge et analyse vibratoire". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAS005/document.
Pełny tekst źródłaThe construction of protective works responds to the need to protect themselves from natural hazards such as erosion or landslides. If the concrete is conventionally used for their construction, wood is regularly used on natural hazards generating low or moderate stresses. For this, practitioners rely on two different approaches, civil engineering and ecological engineering, which require, in this context, the implementation of a structure built on the basis of an arrangement of logs. However, there are knowledge gaps hampering the prescription of these works. In particular, scientists locks concern the assessment of the level of decay, in the sense of mechanical properties, of logs for monitoring existing structures.The aim of this thesis is to develop two methods for assessing the level of decay of silver fir logs from near infrared spectroscopy (NIRS) and vibration analysis. In this thesis, the level of decay is set from the rate of loss in modulus of elasticity (MOE) or modulus of rupture (MOR) in relation to their intact value .The results showed that the methods allowed evaluating the log level of decay both in semi-controlled and in natural conditions. The NIRS method assesses the level of decay from prediction models of $Dw_{MOE}$ and of $Dw_{MOR}$ based on multivariate statistics. The method by vibration analysis measuring the loss rate in dynamic MOE ($Dw_{E_n}$)of the logs, which are characterized by their geometric imperfections.This work helps to deepen knowledge on the assessment of the level of decay of wood. The methods may be considered for application on real structures. These two methods are actually suitable for textit{in-situ} measurements.The objective of this thesis is to develop two indicators, DwNIRS and DwE1, from two complementary methods, the near infra-red spectroscopy (NIRS) and the vibration resonant method (VRM), to assess decay-extent of small-diameters silver fir logs decayed by a microbial community. These indicators are intended to help to practitioners in the diagnostic of the structures. The work is based on a mechanical definition of the decay-extent. A reference indicator DwMOE is defined for this purpose from the normalized loss in modulus of elasticity (MOE) of the logs between intact and decayed states.The thesis is composed of three parts. The first part explores the ability of NIRS to assess decay-extent in semi controlled conditions. Small-diameter logs have been degraded in a greenhouse and monitored at different decay levels. The indicator DwNIRS is calculated from a prediction model using multivariate statistics to predict the reference indicator DwMOE. The second part studies VRM. This method allows measuring dynamically the modulus of elasticity of logs at different decay levels. The third part is dedicated to the comparison of both methods in semi-controlled conditions and also in natural conditions.The results show that both methods allow identifying the effects of the microbial community on wood from early stages of decay. The indicators DwNIRS and DwE1 follow faithfully DwMOE even if the intrinsic variability of wood properties coupled with those bring with the microbial activity alter the precision. Thus, the definition of decay classes from DwNIRS and DwE1 limits the undesirable effects of the variability and brings closer the methods from those already used to assess decay in natural conditions. Finally, the classifications obtained from logs decayed in natural conditions are comparable and allow considering an application on real structures. Both methods are effectively adaptable to in-situ measurements with a limited degradation impact on structures
Décatoire, Rodrigue. "Optimisation des campagnes d'inspection dans le cadre de processus stochastiques de dégradation : Application aux structures en béton armé". Nantes, 2015. https://archive.bu.univ-nantes.fr/pollux/show/show?id=831818a0-80d5-4c3d-a74c-f5adae962f0d.
Pełny tekst źródłaThe development of modern societies has seen the construction of several structures and infrastructures built in reinforced concrete. The management of those structures, potentially large and subjected to important pathologies, aiming at ensuring and guaranteeing their safety and durability has become a true economical challenge. Looking for an optimal inspection, maintenance and repair plan according to safety constraints is one of the possible solutions to address this challenge. This work is bounded by a preventive maintenance context where the concrete degradations may lead to the corrosion of the reinforcements and not to structural failure. The corresponding degradation models are put in an uncertainty context where the spatial variability of the environmental exposure and the concrete properties are accounted for. Based on such predictions, an adaptive design of experiments helps to identify, at a given time, where the structure should be inspected in order to evaluate its degradation state which will indicate the need for maintenance or a repair action. A decision tree therefore allows to predict the probabilistic evolution of the structure state, including the effect of maintenance and repairs. This tree is then used in an optimisation process which aims at finding where and with which inspection technique the structure is to be inspected to minimise both the expectation of the exploitation costs and the associated uncertainties due to the measurement errors, accounting for the stakeholder’s constraints
Lagarrigue, Mélanie. "Détection, identification et préconcentration de produits de dégradation d'agents de guerre chimique organophosphorés par couplage électrophorèse capillaire-spectrométrie de masse". Phd thesis, Paris 6, 2007. http://pastel.archives-ouvertes.fr/pastel-00004615.
Pełny tekst źródłaBana, Franck Lionel. "Dégradation par électromigration dans les interconnexions en cuivre : étude des facteurs d'amélioration des durées de vie et analyse des défaillances précoces". Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENI081/document.
Pełny tekst źródłaIntegrated circuits are part of our nowadays life as they are presents everywhere; as well as in daily life or industry. They are continuously downscaled to increase their performances. As a result, this downscaling lead to complex interconnects grid architectures. Interconnects which are metal lines carrying electric signal in the circuit are thus more and more sensitive to electromigration failure. This I because of increasingly higher current densities they carry. Obviously, in advanced technology nodes, it is more and more difficult to ensure the reliability level required for interconnects. Interconnects lifetime reduction is linked to increasing difficulty to perform all process steps with these very small features and also to increasing failure times dispersion. In the first part of the work presented here, we deepened the understanding of mechanisms involved during electromigration degradation. We have thus shown the fundamental role played by the microstructure and the chemical composition of the line in increasing its lifetime. The second part of the work dealt with the improvement of statistical analysis of failure times. We thus focused on early failures and the bimodal failure times distributions they generate. As far as that goes, the multilink structure we have designed answers the fundamental question of increase test sampling. This lead then to improved precision at very low failure rates for robust lifetime's extrapolation to use conditions
Parodi, Aurély. "Impact de nouveaux modes de gestion sur l’accélération de la dégradation de déchets ménagers : approche multiparamétrique et multi-échelle". Limoges, 2010. https://aurore.unilim.fr/theses/nxfile/default/6f645e4d-e00a-4f35-8d61-118e54ac2faa/blobholder:0/2010LIMO4077.pdf.
Pełny tekst źródłaThis research is a multi-parametric and multi-scale comparison of municipal solid waste pretreatment in order to accelerate waste degradation in landfill conditions. This work is part of two research projects (ELIA and BIOPTIME) in which 21 types of treatment were tested at 68 L and 23m3 scale. In a first time, this research aims at developed a leaching test protocol adapted to the waste matrix and to highlight differences between pretreatments. The protocol established combines liquid phases, gaseous and solid analysis during a period of 120 hours without renewal. The organic compounds mobilized in liquid phase are relevant indicators of the potential leaching of waste. With the results for all considered matrices (analytical monitoring during the pilot operation of waste, leachate and biogas) correlated with the leaching test data, two treatments were found to have a real impact on the biodegradation of waste. This multi-parameter approach has also identified the fractionation of organic compounds according to their hydrophobicity and the index SUVA as relevant indicators to assess state of waste degradation or stabilization. A complete water and mass balance of the most efficient treatments confirmed the results of the analysis
Haghighi, Firoozeh. "Fiabilité et analyse de survie : le modèle semi-paramétrique de dégradation : une généralisation de la famille Weibull et ses applications". Bordeaux 2, 2004. http://www.theses.fr/2004BOR21136.
Pełny tekst źródłaWe consider the general degradation path model in dynamic environment. We proposed semi parametric estimators and we studied their asympthotic properties. We present a new extension of weibull families. We consider goodness-of-fit test for weibull against generalized weibull, applied Nikulin-Moore statistic. We compared chi-squared test and kullback-lieber test in the case of censored data
Dutruch, Lionel. "Etude de la réticulation, du vieillissement et de la dégradation thermique de bisnadimides : couplage analyse thermogravimétrique - chromatographie en phase gazeuse". Lyon 1, 1996. http://www.theses.fr/1996LYO10252.
Pełny tekst źródłaLazar, Oana. "Analyse et modélisation des mécanismes de dégradation de grille des transistors à haute mobilité électronique (HEMT) de type AlGaN/GaN". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30349.
Pełny tekst źródłaThe recent introduction of wide bandgap materials revolutionizes the RF field of power modules. Due to the high-power levels for telecommunication frequency bands, GaN technologies represent nowadays a major integrated alternative which is believed to gradually replace III-V GaAs technologies (SSPA amplifiers), and even to compete with wave tubes technologies (TWTA amplifiers). Development of GaN material in the last decade is proved by the market release of several GaN versions, such as GH50 and GH25 from UMS. These batches are issued from technological versions that feature delicate mastering of the various degradation mechanisms induced by thermal, electrical or RF stress: IDQ tests, HTRB, HTOL, etc. The complexity of the involved processes (thermal, piezoelectric, ...) often makes difficult the analysis of mechanisms that caused the identified damage, and it is necessary to establish a rigorous multi-physics study in order to identify the sensitive electrical and technological parameters. The analysis associated with this work are based on cross non-invasive measurements, in transient and spectral domains. This purely metrological approach reaches its limits insofar as the crossing between non-destructive and destructive data cannot be applied to the same components, nor before/after application of a stress. Therefore, the objective of this thesis consists in giving some key indicators which can be useful when converging from these industrial and under development technologies to more robust and more efficient processes. In this way, we will be able to improve also our knowledge concerning the multitude and poorly controlled degradation kinetics. The identified technologies for technological support are the qualified or under development dies, issued from UMS: GH50 and GH25. On each of these versions, we can identify limiting mechanisms both at instant t0, and during evolution under stress. From technology maturation point of view, we can identify sensitive areas that limit operational security zones of the devices, and enable technologists to improve the technological processes. In addition, this dual input technology will allow us to implement the working methods that we have developed in this thesis. Transient techniques (non-invasive), such as I-V-T DC and pulsed measurements, will be analyzed and correlated with low frequency noise measurements (in frequency domain), on witness (virgin) components. By the means of electrical measurements, gate lag and lag drain phenomena can be identified, which are the main limiting factors for power applications and pulsed radar applications. Low frequency noise characterizations are recognized as reliable indicators for the analysis of defects in different areas (active or not) of the devices under test. The analysis and the location of these noise sources is fundamental for the next step. Then, these associated measurements and modeling techniques are used to study stressed (aged) components. On one hand, the evolution of electric linearity characteristics allows the comprehension of the stress consequences on the operational behavior of the device. On the other hand, the evolution of noise spectra allows the access to a corpuscular view of the defect that initiates the lowering of the transistor performances. These evolutions constitute a reliable database, which can be used in order to better understand the immediate and slow changes in reversible and irreversible degradation process of the devices under test: modification of the Schottky diode, presence of acceptors traps, mobile and fixed charges, slow and fast traps phenomena
Noël, Cyril. "Réseaux microbiens de dégradation des hydrocarbures aux interfaces oxie/anoxie des sédiments marins côtiers". Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3038/document.
Pełny tekst źródłaCoastal marine ecosystems are constantly subject to pollution, particularly hydrocarbons, because of their location and their environmental characteristics. The key role of microorganisms in the degradation of these pollutants is now well described. However, fluctuating oxygenation conditions in these coastal environments, due to tides and macrofauna bioturbation activities influence microbial communities.Thus, this thesis work aimed to characterize the assembly of microbial hydrocarbonoclastic communities of coastal marine sediments subjected to oxic/anoxic oscillations in the presence of oil during a bioreactor experiment. The adaptation of MOHCB, particularly of Alcanivorax and Cycloclasticus genera, to these oxygen variations has been investigated by oligotyping. Ecotypes were identified according to the oxygenation conditions demonstrating adaptation capacities of these two genera to the oscillating oxygen conditions. The structure of archaeal communities (16S rRNA transcript sequencing) did not show any modification related to the oxygenation conditions thus demonstrating greater adaptation and/or resistance capacities in these microorganisms compared to the bacterial communities. Finally, metagenomics analyses revealed a specific functional response to oxic/anoxic oscillations. Thus, this thesis provides new insights into the influence of oxygenation variations on microbial communities and consequently on the degradation of hydrocarbons in coastal marine ecosystems
Piettre, Charline. "Caractérisation des gènes gouvernant la dégradation de l'urée chez Alcaligenes eutrophus H16". Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10201.
Pełny tekst źródłaTerrei, Lucas. "Comportement au feu du matériau bois : auto-inflammation, dégradation et auto-extinction". Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0118.
Pełny tekst źródłaThe construction of positive energy and low carbon footprint buildings is a real response to the environmental issues and challenges of the coming decades. An increasing number of high-rise building construction projects made largely of wood are either under study or under construction. A key issue for the construction of such buildings is the fire behavior of these structures. Indeed, when the wood is subjected to a high heat flux, it will degrade and it can self-ignite. Conversely, in certain conditions, wood can self-extinguish. However, the bibliography shows the disparity concerning experimental results for a same material subjected to a given test such as the cone calorimeter. The results on the wood extinction remain limited in view of recent research carried out on this phenomenon. The aim of the thesis is to experimentally study the self-ignition, degradation and self-extinction of the wood material used in buildings. For this, many tests at different scales have been performed to examine the ability of the wood material to self-ignite or self-extinct under prescribed conditions. A total of 600 tests, were performed in vertical orientation and allowed to consolidate results with a statistical approach. A dedicated experimental setup has been deployed on each experimental device studied: an infrared camera providing to measure the surface temperature of the samples when they are subjected to a heat flux, two fast cameras (visible and infrared) in order to record the location and the auto-ignition mechanisms and very thin thermocouples embedded in the wood to measure the temperature evolution in the material according to fixed conditions. Results showed that for the auto-ignition (i.e. without pilot), the notion of ignition temperature of the material could be questionable when the ignition occurs at short times. Indeed, the flame appearance is, in most of the experiments, at a distance far from the exposed surface to the heat flux. The ignition mechanisms do not depend on the surface temperature but on the gas / air mixing conditions as well as the mixture temperature. The auto-ignition surface temperature makes therefore sense only for long auto-ignition times, for which ignition occurs close to the surface. The samples degradation depends on many factors: sample orientation, sample humidity, wood species, oxygen concentration in the atmosphere. The effect of these parameters was considered in this work. A particular attention was focused on the establishment of a metrology aimed at obtaining precise and accurate measurements. Very thin thermocouples, embedded in the sample and oriented parallel to the isotherms allow a better estimation of the temperature and were therefore used. Finally, a new experimental device based on two cones calorimeter arranged on a sliding table system was set up and made it possible to determine simple criteria for wood self-extinguishment at small scale
Gomes, Romeu. "Compréhension des mécanismes de dégradation des outils de découpage à chaud de tôles d'acier trempant au bore-manganèse". Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2018. http://www.theses.fr/2018EMAC0018/document.
Pełny tekst źródłaCar manufacturers are building using a self-hardening high strength boron steel (22MnB5) for safety and environmental concerns. But the shaping of sheets made of these kind of steel imposes on tools severe mechanical stresses and strong thermal transfer. The integration of a blanking function in transfer presses is a response to reach high profitability, but blades are subjected to the same durability problems. The aim of this thesis is to understand how hot blanking tools are wearing in order to give to manufacturers tool material guidelines (X38CrMoV5-3 or X70CrMoV5-2) and process parameters guidelines. To do so, an estimation of mechanical stresses and thermal solicitation is required. The methodology is based on four steps: literature search, hot blanking trials on a specific module of ICA laboratory industrial pilot MEFISTO, finite element simulations of the operation, and microstructural analysis. The state of art is focused on the description of the operation, the physical and mechanical properties of the blank material and tools materials, the blank/tool interface behavior, and the techniques used simulate the hot blanking process. Trials on the hot blanking module provided blanking force and observations of worn blades. These informations are needed to validate the finite element model. This model shows that mechanical stresses are local, intense and slides in the blade cutting edge. Moreover, the blade heating generates a surface temperature close to tool steel tempering temperature. Experimental results compared to numerical ones allow to understand the link between thermo-mechanical stresses and how the damage occurs
Bouexière, Isabelle. "Analyse de l'influence de polyélectrolytes sur la floculation et la filtration de suspensions colloïdales par une méthode ultrasonore". Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPL099N.
Pełny tekst źródłaRaguideau, Sébastien. "Analyse de données de métagénomique fonctionnelle par NMF pour la modélisation de la dégradation des fibres par le microbiote intestinal humain". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLA027/document.
Pełny tekst źródłaThe purpose of this work of thesis is to model the capacity of degradation of non-digestible polysaccharides by the human intestinal microbiote. To this end we exploit metagenomic data. We use abundances of nucleotide sequences in 1408 samples whose metabolic function are assigned by annotation against a database. The sequences are annotated with functional markers. Upon manual selection of 86 functional markers relevant to the activity of metabolisation of polysaccharides, we their abundances variation among the metagenomic samples are studied.We propose an ecological approach in modeling the human intestinal microbiote. We consider the intense functional selection of this ecosystem and assume that identical cluster of metabolic functions can be found in different proportions in every human gut microbiota. We propose the term of functional assembly as to account for spacial and temporal co-occurence of functional cluster. In practice, theses assemblies are determined by their composition and can be interpreted as combinations of functional traits aggregated at the levels of the cluster of microorganisms composing each assembly. Functional assemblies are inferred by the means of Non-Negative Matrix Factorization (NMF). This method allows to determine the composition of functional assemblies and their abundance in each of the 1408 metagenomic sample.Furthermore, we exploit metabolic information from bibliographic resources and 190 microbial genomes in order to specify the composition of these functional assemblies. This information is translated in the form of a constraint.We find 4 assemblies by considering a consensus between various criteria. The use of metabolic information allow to interpret theses assemblies biologically. By exploiting the metadata of the 1408 samples, we observe a different behaviour for the samples coming from individuals suffering from Crohn disease. We validate this observation on external data.We proposed a reductionistic approach allowing to represent an important metabolic process at the level of the microbiota. We find a small number of 4 functional assemblies which are biologically likely and approach well the 1408 metagenomic samples
Fruitier-Arnaudin, Ingrid. "Les hémorphines : peptides biologiquement actifs issus de l'hémoglobine : détermination d'une voie potentielle de biosynthèse et de dégradation in vivo et mise en évidence de sites récepteurs cibles". La Rochelle, 1999. http://www.theses.fr/1999LAROS039.
Pełny tekst źródłaTouzeau, Josselyn. "Approches numérique multi-échelle/multi-modèle de la dégradation des matériaux composites". Phd thesis, Ecole Centrale Paris, 2012. http://tel.archives-ouvertes.fr/tel-00837874.
Pełny tekst źródłaNguyen, Thi-Phuong. "Etude des effets de la pollution atmosphérique sur la dégradation de la gélatine photographique". Rouen, 1998. http://www.theses.fr/1998ROUES101.
Pełny tekst źródłaIsselmou, Mohamed Habib Mohamedou. "Applications des méthodes de l'analyse thermique à l'étude du vieillissement des polymères". Thesis, Clermont-Ferrand 2, 2013. http://www.theses.fr/2013CLF22404/document.
Pełny tekst źródłaThis work focuses on the contribution of thermal analysis techniques to the multi-scale study and monitoring of the phenomena of thermal and photochemical aging of polymer materials.After a bibliographic study on the state of the art in this field, the thesis presented the results obtained during the application of the Differential Scanning Calorimetry (DSC) to the study of the aging of these materials. First of all, this part focused on the crystallinity of Poly (Lactic Acid) (PLA) and Poly (Ethylene Terephthalate) (PET). A correlation was established between the results obtained from the DSC and those obtained by Fourier Transform Infrared Spectroscopy (FTIR) with respect to the evolution of the crystallinity during aging of the polymer.Furthermore, our work focused on the follow-up of the thermo-optical properties by photo-DSC. This work was illustrated by the study of Poly (Vinyl Chloride) (PVC).A final section of this work focuses on the DSC and ThermoGravimetric Analysis (TGA) monitoring of the diffusion of water in the polymer matrix during aging. Here, the technique known as Thermoporosimetry was chosen. The results were compared with those obtained by coupling ATG-DSC-Moisture. The type of products which are chosen in this part of study, were Polyisoprene (PI) and on PolyDiMethylSiloxane (PDMS)