Дисертації з теми "Résistance in-situ"
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Sniezewski, Julien. "Etude in situ sous gradient thermique de l’écaillage d’alliages alumino-formeurs et de barrières thermiques aéronautiques." Phd thesis, Toulouse, INPT, 2008. http://oatao.univ-toulouse.fr/7229/1/sniezewski.pdf.
Zhao, Fei. "Study on mechanical properties of the in situ TiB/TiC reinforced titanium matrix composites." Troyes, 2010. http://www.theses.fr/2010TROY0030.
The aim of this research is to study the effects of reinforcements TiB and TiC materials by experimental analyzing structures and mechanical testing of properties of in situ synthesize TiB/TiC reinforced titanium matrix composites. The tensile, friction and fatigue properties of in situ TiB/TiC reinforced composites structures were tested. Finite element analysis was also used to simulate the effect of the reinforcements. The results show that the reinforcements can play an important role in the composites properties. The elastic modulus and shear modulus have some relation with the type, the quantity, the shape and the distribution of the reinforcements in the composite materials. Some formulas about the modulus of the composites are suggested by modelling the composite behaviours with numerical method. The reinforcements can prevent the crack initiation and propagation in static load. For the fatigue properties, the reinforcement TiB reduces the fatigue life of the composites under high level of load, but increases it in low load conditions, while TiC reinforcements can improve the fatigue strength of the composites. So in practice, the applying conditions of the composites should be considered. The contents of the reinforcements should be determined by taking account of the manufacturing costs, so that we can to optimize the practical needs and to but reduce the costs
Chelta, Antoine. "Projet d'instrumentation "in situ" monopuits pour la reconnaissance de caractéristiques sismiques de sols." Montpellier 2, 1990. http://www.theses.fr/1990MON20207.
Sasaki, Layla. "Influence du vieillissement sur la résistance à la fissuration par fatigue à haute température d'alliages de titane pour mâts-réacteurs." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2018. http://www.theses.fr/2018ESMA0006/document.
The conception of more efficient aircraft engines induces increased stress and temperature levels on the titanium alloys constitutive of the engine pylon. On the one hand, these materials have to be qualified in terms of damage tolerance. On the other hand, the long term high temperature exposure of these titanium alloys gives also rise to the question of thermal aging and metallurgical stability. Hence, the dimensioning as well as the maintenance of such aerostructures need to be considered in the light of both these critical issues.In the present work, the cyclic behavior as well as the fatigue crack resistance of different titanium alloys (TA6V, Ti 6242 et Ti 17), with various microstructures were studied after different aging conditions. Aging induces mainly an increase in crack growth rates at high values of the stress intensity factor, at room temperature. Subsequently, a thorough characterization procedure of this phenomenon was undertaken,including various types of loadings, at different scales and associated with fractographic analyses. The results allowed to suggest a damage scenario before and after aging, in the case of the alloy most affected by aging: theTi 17 alloy. This scenario shows the occurrence of a « static » mode of failure, which is linked to a damage process associated with intralamellar fracture and decohesion, without noticeable changes in the cyclic behavior. Finally, a time-temperature equivalency approach was developed to describe the kinetics of degradation of the mechanical properties induced by aging
Laflamme, Christian. "Agents du bioterrorisme : détection in situ de gènes de résistance aux antibiotiques chez les spores de Bacillus sp." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25821/25821.pdf.
Cristofari, François. "Etude du comportement et de la résistance mécanique d'un pancréas bioartificiel pour l'homme. Caractérisation expérimentale et simulation numérique." Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0055.
In order to treat type 1 diabetics, a bioartificial pancreas has been developed. It consists in the encapsulation of insulin producing cells: it is made of porous membranes which isolate cells from patient antibodies, allowing the glucose and the insulin to pass through. Before its commercialization, it is necessary to verify that its mechanical behavior allows it to be implanted in a human body without any risk for the patient. The mechanical strength of the membranes under loading is therefore studied. Their structure is first obtained using scanning electron microscopy and X-ray nanotomography. Tensile tests are then done at both macroscopic and microscopic scales, digital image correlation techniques being used to characterize the membranes at each scale. At the same time, a numerical model using finite element method is built based on the microstructural and mechanical characteristics of the membranes experimentally identified. A methodology to compare the experimental and numerical results behavior of the membranes is proposed and used. The results of the study are finally considered to assess the possibility to use the device in clinic phase
Devillard, Julie. "Lien entre microstructure et résistance à la compression du gypse moussé." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI043.
This study focuses on the microstructural and mechanical characterization of foamed gypsum, the core material of lightweight gypsum boards, with a high (75%) multi-scale porosity. The objective of this work is to determine the influence of the microstructure of foamed gypsum on the hardness measured in spherical indentation and to analyze the damage mechanisms for different microstructures. Spherical indentation tests were conducted on samples showing variations in microstructural features of foamed gypsum. The results of these tests show that density has a first-order influence on hardness and that the dispersion of hardness measurements in spherical indentation can be related to heterogeneity in macroporosity. In situ indentation tests were also carried out, with X-ray tomography and digital volume correlation (DVC) analysis, in order to accurately study the damage mechanisms. Two different modes of damage were determined according to the densities considered (variable macropore fraction). The results of these tests were used to feed an analytical model, based on an energy criterion that links the indentation force to the damaged area under the indenter. This provides the prediction of the indentation force-displacement curve specific to a microstructure with a scan of the initial microstructure as the only input data. Numerical modelling was also carried out using the finite element method with consideration of the actual microstructure, at two scales. The densified areas were properly predicted by different behaviour models based on plasticity criteria
Findik, Busra. "Formulations innovantes pour la résistance au feu de systèmes actifs par addition physique et génération in situ de charges minérales." Electronic Thesis or Diss., Lyon 1, 2022. http://www.theses.fr/2022LYO10117.
One of Nexans' major challenges is to develop fire-resistant cables for buildings, industry and infrastructure networks. In this context, one of the systems developed is a three-layer insulated electric cable. The main disadvantage of the composite material used in the composition of this electrical cable is its high filler content, necessary to obtain a material that meets the expected electrical and thermal performance. This high filler rate can constitute an obstacle to the fabrication process of the material due to the high viscosity induced, but also deteriorate its final properties such as flexibility and hardness. The alternative strategy developed aiming to reduce the filler rate and thus reduce the viscosity of the materials to facilitate their implementation was to synthesize the fillers directly in the molten polymer. The sol-gel process by which an inorganic phase can be generated in situ during the extrusion process through the use of inorganic precursors is particularly suitable. Indeed, the inorganic precursors can play the role of solvent or plasticizer prior to their reaction, thus making it possible to lower the viscosity of the complete system. From these observations stems the main objective of the work of this thesis, which is to develop fire-resistant materials by integrating charges generated in situ by reactive extrusion in a pre-charged polymer matrix
Le, boulch Pauline. "Déterminants moléculaires de la résistance au puceron vert (Myzus persicae) chez le pêcher (Prunus persica) : étude multi-omique des réponses à l'infestation." Electronic Thesis or Diss., Avignon, 2022. http://www.theses.fr/2022AVIG0371.
Of the many pests that plants face, aphids are certainly the most damaging to crops due to their rapid multiplication, the direct damage they cause and the plant pathogenic viruses they transmit. The green peach aphid (Myzus persicae, Sulzer) is a generalist pest that attacks a wide range of plants including peach, its primary host, but also numerous secondary hosts from various botanical families including different cultivated species. Previous work has highlighted peach accessions with resistance to M. persicae conferred by the Rm locus that was characterised by an antixenosis phenomenon that rapidly causing the aphids to leave. The objective of our study was to identify, using an integrated transcriptomics and metabolomics approach, the factors involved in the expression of resistance to M. persicae in peach trees in order to obtain a quasi-exhaustive description of the biological functions activated or repressed by the infestation. We compared the responses to infestation of two peach genotypes, GF305 susceptible to M. persicae and Rubira carrying the Rm2 resistance gene, 48 h post-infestation, a period corresponding to the effective establishment of Rm2-induced resistance.Comparative transcriptomic and metabolomic analysis of the two peach varieties revealed a very limited response of GF305 to infestation while profound reconfigurations in Rubira were observed. The transcriptional reconfiguration resulted in a repression of genes involved in growth and development functions and an overexpression of defence genes, indicating a reorientation of cell function towards defence. This observation was confirmed by the significant reduction in metabolic pools of carbon, nitrogen and sulphur and by the accumulation of caffeic acid conjugates with anti-appetent or toxic properties towards aphids. Among the defence genes, the overexpression of PRR and NLR receptors suggested a joint activation of both branches of the plant immune system, PTI and ETI. Furthermore, the enrichment of oxidative stress-related genes, coupled with the activation of H2O2-generating metabolic pathways such as photorespiratory glyoxylate synthesis and P5C/proline futile cycle activation, underlineed the probable involvement of ROS synthesis in Rubira resistance to M. persicae. The appearance of necrotic lesions indicative of a hypersensitive reaction could also be attributed to an oxidative burst in response to infestation. The triggering of an acquired systemic response was also suggested by the activation of salicylic and pipecolic acid metabolism. Finally, as the involvement of pipecolic acid in plant resistance to aphids is poorly documented and in order to determine the role of this compound in peach resistance, the effect of an exogenous supply of pipecolic acid on the escape behaviour of M. persicae and on the development of aphid colonies, as well as on the metabolic profile of the apices was investigated. Although this experiment did not show the capacity of pipecolic acid to induce resistance, it provided new informations concerning the metabolic markers inducible by this molecule. To conclude, this work illustrates the extent and complexity of the expression of resistance to M. persicae conferred by Rm2 and underlines the interest of integrating transcriptomic and metabolomic data for the analysis of the plant/aphid interaction. This functional knowledge will be crucial in order to exploit natural sources of resistance and sustainably control aphid populations
Kay, Élisabeth. "Transfert latéral d'ADN chez les bactéries : étude de paramètres biotiques et abiotiques affectant la fréquence des transferts in situ." Lyon 1, 2002. http://www.theses.fr/2002LYO10245.
Mabssout, Mokhtar. "Introduction à la reconnaissance dynamique de sols in situ par système harmonique sismique." Montpellier 2, 1993. http://www.theses.fr/1993MON20155.
Fortineau, Julien. "Caractérisation et contrôle ultrasonore in situ de membranes échangeuses de protons." Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4004/document.
No summary available
Carvou, Erwann. "Réalisation et caractérisation de structures intégrées en technologie BCD de micro-capteurs de positionmagnétiques réalisés à partir de couches de silicum polycristallin dopées in-situ." Rennes 1, 2003. http://www.theses.fr/2003REN10015.
Tubbs, Emily. "Importance of intracellular Mitochondria-Associated endoplasmic reticulum Membranes (MAM) in insulin-resistance." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10210.
Mitochondria-associated endoplasmic reticulum membranes (MAM) are functional domains between both organelles involved in Ca2+ exchange, through the voltage-dependent anion channel (VDAC)-1/glucose regulated protein 75 (Grp75)/inositol 1,4,5-triphosphate receptor (TP3R)-1 complex, and regulating energy metabolism. Whereas mitochondrial dysfunction, ER stress, and altered Ca2+ homeostasis are associated with altered insulin signalling, the implication of MAM dysfunctions in insulin resistance is unknown. During my PhD, my work has underlined a new role of MAM in hepatic insulin- resistance. T have developed a quantitative method called in situ Proximity Ligation Assay to visualise and quantify the interactions between ER and mitochondria. T have shown that MAM integrity is required for insulin signalling and that disruption of MAM is implicated in hepatic insulin resistance. Preliminary data also suggest that MAM alterations are also associated with muscle insulin resistance. T have also identified the presence of the protein kinase B (PKB), a key protein involved in metabolic effects of insulin, at the MAM interface, and demonstrated that its phosphorylation by insulin is altered in this fraction in liver of diabetic mice. Lastly, T have also participated to the identification of: 1) the presence of cyclophilin D (CypD) at MAM interface which regulates calcium transfer from ER to mitochondria in both cardiomyocytes and hepatocytes, and 2) a regulation of MAM by glucose in liver, which is involved in the regulation of mitochondria dynamics and function during nutritional transitions. Consequently, my work improved the knowledge on the composition, function and regulation of MAM, and highlighted MAM as a potential new target for the modulation of hepatic insulin action and metabolism
Zerzouri, Maroua. "Faisabilité d’élaboration des poudres pré-géopolymères par mécanosynthèse : caractérisation physico-chimique et application aux pâtes, mortiers et enrobés bitumineux." Thesis, Université Gustave Eiffel, 2021. http://www.theses.fr/2021UEFL2039.
Geopolymers are inorganic materials made from compounds of natural origin (kaolin, for example), or from industrial waste (fly ash, blast furnace slag, etc.). Their excellent physicochemical and mechanical properties justify the growing interest they arouse in the construction field. However, their potential of employment remains limited due to the use, during their preparation, of highly concentrated alkaline solutions causing significant health risks and transport storage difficulty; hence it is necessary to implement solvent-free manufacturing techniques.This thesis aims to propose a new producing pre-geopolymer powders (PGP) method by “mechanosynthesis” that are easy to transport and store. Several raw materials, of different types and chemical compositions, were tested as aluminosilicate precursors (fly ash, metakaolin, blast furnace slag and clay); they were activated by different alkaline mixtures (NaOH, KOH, Na2SiO3 and CaO), at fixed mass ratios. The effect of several process parameters was considered, including milling time and speed rotation. The produced pre-geopolymer powders were then incorporated into formulations of pastes, mortars and bituminous mixes. The pastes physicochemical and mechanical properties were studied. The obtained results were compared with those of pastes made by the conventional method under the same conditions. The kinetics of pastes geopolymerization reaction were followed by infrared spectrometry in situ just after the hydration of the PGP. In addition, the indirect mechanosynthesis process has been used to improve the reactivity of clay.The results demonstrated the mechanosynthesis process efficiency for producing the pre-geopolymer powders. These give rise after hydration to geopolymer pastes with a similar structure to that of conventional geopolymers. This process has also helped to improve the mechanical performances of geopolymer products. The pre-geopolymer powders based on illitic clay, produced by indirect mechanosynthesis, give rise to pastes with mechanical resistance reaching 72.5 MPa after 28 curing days at 20 ° C and 50% of relative humidity, against 12.5 MPa for the classic case. The results obtained on slag-based mortars show mechanical strengths reaching 38 MPa after 28 curing daysFinally, the preliminary results on slag PGP-based bituminous mixes reveal better water and rutting resistance, even after 100,000 cycles, than those of the reference formulas without PGP
Kouddane, Bouchra. "Évaluation non destructive optimale des bétons par couplage des méthodes CND." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0084.
Understanding the in situ mechanical properties of concrete is essential for determining the structural capacity of both existing structures and new constructions. The recent methodology for assessing concrete strength in an existing structure involves integrating nondestructive testing (NDT) techniques with destructive measurements (coring) to establish a conversion model that correlates mechanical strength with nondestructive measurements. Subsequently, the conversion model is applied to estimate the local mechanical strength at each testing location based on the corresponding NDT values.The Rebound Hammer (RH) test and the Ultrasonic Pulse Velocity (UPV) test are widely used for estimating the compressive strength of concrete. However, the accuracy of the results obtained from these methods can be influenced by various factors. To mitigate these effects, the strategic combination of these two nondestructive tests provides an effective way to evaluate concrete strength in existing structures. Therefore, the aim of this thesis is to analyze the assessment methodology of structures by combining nondestructive techniques and to offer practical recommendations that can enhance the reliability of in-situ concrete strength. For this purpose, a simulator was developed to analyze the methodology of nondestructive assessment using an extensive dataset derived from various sources, including in-situ studies, as well as generated synthetic data.The primary contribution of this study is to propose a new model identification approach based on multi-objective optimization to predict the mean strength of concrete and its variability, based on the combination of NDT measurements. Monte Carlo simulations were carried out to check the performance by considering the uncertainty of NDT measurements and the variability of concrete. The results highlighted the effectiveness of the multi-objective method in determining both the average strength and the variability of strength compared to other approaches. Furthermore, this innovative approach enables enhanced accuracy in estimating concrete properties with a reduced number of cores compared to traditional methods.In addition, a thorough and accurate representation of the structure under examination can be achieved by carefully choosing the core locations. The efficacy of various suggested sample strategies has been evaluated in this study in order to select the optimal locations for the core extractions. Through these thorough comparisons, the study aims to discover the sampling plan that best aligns with the specific objectives of evaluating concrete strength. It is suggested to use variance sampling, which appears to be a suitable alternative for reducing inherent uncertainties in the nondestructive assessment process [...]
Alwash, Maitham Fadhil Abbas. "Assessment of concrete strength in existing structures using nondestructive tests and cores : analysis of current methodology and recommendations for more reliable assessment." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0587/document.
To assess concrete strength in an existing structure, the current methodology combines nondestructive measurements (NDT) like rebound hammer or/and pulse velocity with destructive technique (cores) in order to implement a relationship ‘‘conversion model” between the compressive strength and NDT measurements. The conversion model is used to estimate the local strength value at each test location using the corresponding NDT value.Then the estimated mean strength and/or estimated strength standard deviation (concrete strength variability) values are calculated. However, the reliability of these estimated values isalways a questionable issue because of the uncertainties associated with the strength assessment based upon NDT measurements. To improve the reliability, the uncertainties must be reduced by specifying and controlling their influencing factors. Therefore, the objective of this thesis is to analyze the current assessment methodology in order to provide practical recommendations that can improve the reliability of assessing the in-situ strength in existing concrete structures by nondestructive tests and cores.To this end, a simulator was built in order to analyze the effects of the most influencing factors using a large campaign of datasets from different sources (in-situ or laboratory studies,and generated synthetic data).The first contribution of this work is the development of a new model identification approach“bi-objective” that can efficiently capture the strength variability in addition to the mean strength. After studying the effect of the way of selection the core locations, a method was proposed to select these locations depending on the NDT measurements “conditional selection” that improves the quality of assessment without additional cost. A third innovation was the development of a procedure to identify the relation between the number of cores and the accuracy of the estimation. Finally recommendations were derived in order to providemore reliable estimated values
Venteo, Lydie. "Etude des proteines du cycle cellulaire, de la résistance aux inhibiteurs des topoisomérases et des virus polyoma dans 84 tumeurs cérébrales humaines astrocytaires et oligogliales : immunohistochimie, hybridation in situ et biologie moléculaire." Reims, 2007. http://www.theses.fr/2007REIMP214.
Barbeyrac, Bertille de. "Application des techniques d'hybridation au diagnostic des infections à mycoplasmes et chlamydia trachomatis et à la détection du gène de résistance aux tetracyclines TET(M) chez certaines bactéries responsables d'infections génitales." Bordeaux 2, 1994. http://www.theses.fr/1994BOR28307.
Ghazi, Arash. "Microstructural computational modeling of the mechanical behaviour of closed-cell foams: from tessellation-based to CT scan-based modeling." Doctoral thesis, Universite Libre de Bruxelles, 2020. https://dipot.ulb.ac.be/dspace/bitstream/2013/306841/3/Thesis.pdf.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
Derode, Benoît. "Approche expérimentale in-situ de la signature sismique du rôle des fluides dans la rupture des zones de faille : application à la rupture des grands versants rocheux fracturés." Phd thesis, Université Nice Sophia Antipolis, 2013. http://tel.archives-ouvertes.fr/tel-00942554.
Trinh, Viet Nam. "Comportement hydromécanique de matériaux constitutifs de plateformes ferroviaires anciennes." Phd thesis, Université Paris-Est, 2011. http://pastel.archives-ouvertes.fr/pastel-00647893.
Esslimani-Sahla, Majida. "Marqueurs moléculaires de réponse aux hormones ovariennes et au tamoxifène dans les lésions précancéreuses mammaires et cancers invasifs du sein." Montpellier 1, 2006. http://www.theses.fr/2006MON1T025.
Talhouët, Anne-Claire. "Stratégies d’acclimatation de deux plantes alpines, Soldanella alpina et Geum montanum, à deux points clefs de leur developpement Dynamic acclimation to sunlight in an alpine plant, Soldanella alpina L.” Epidermal UVA screening capacity measured in situ as an indicator of light acclimation state of leaves of a very plastic alpine plant Soldanella alpina L." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS018.
Alpine plants are subject to stressful conditions, with extreme temperatures, intense light, and UV radiation. The majority of these plants therefore develop over a short growing period. But some exceptions exist: Soldanella alpina and Geum montanum keep their leaves during several vegetation periods. They are thus confronted with brutal variations of their environment, in particular during the changes of season, which is a source of oxidative stress. Thus in spring, the snow melts and the leaf temperature quickly goes from -10 to 40 ° C coupled with an increase in light intensity and in autumn the leaves, hitherto covered by the surrounding vegetation and therefore acclimated to shade, have to face strong lights. To tolerate these rapid changes, we can assume that S. alpina and G. montanum have developed unique acclimation strategies that I sought to understand during my thesis.In autumn and spring, the main concern for the leaves of S. alpina and G. montanum comes from the fact that they are acclimated to low light intensities.We have shown that the leaves acclimate to the change in light intensity through morphological changes and by improving their photoprotection thanks to an increase in the concentration of flavonoids for the 23 major flavonoids found in the epidermis and mesophyll of the leaves in S. alpina. However, there is no acclimation of photosynthesis to changes in light intensities in the fall: the leaves confronted with strong lights cannot manage to use all of the light energy. This excess energy creates an imbalance between the total electronic flux and the electronic flux used for photochemical processes which result in exacerbated oxidative stress, in the spring, when in addition to light stress there are extreme temperatures. After having succeeded in estimating the various electronic fluxes, we observe in S. alpina and G. montanum the existence of a flux of excess electrons, not dissipated by photosynthesis. The dissipation of energy in the form of heat and a strong capacity of the malate valve and the antioxidant system allow respectively to limit and partly consume the excess electrons
Haidara, Fanta. "Étude des mécanismes de formation de phases dans des films minces du système ternaire Al-Cu-Fe." Phd thesis, Université Paul Cézanne - Aix-Marseille III, 2011. http://tel.archives-ouvertes.fr/tel-00647911.
Çami, Kastriot. "Imagerie du module de cisaillement in situ du sol par méthodes d’ondes de surface et essais géotechniques : caractérisation des petites aux grandes déformations." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1216/document.
The difficulty of dealing with complex geotechnical projects implies the necessity to determine adequately soil’s behaviour with strain’s increase. The information provided for these geotechnical studies mostly concerns soil’s in situ resistance and it is only punctual. In order to fully characterize soil’s behaviour with strains, this work exposes a detailed study of the shear modulus evolution with increasing strain by using surface waves methods, geotechnical laboratory tests such as soil mechanics tests and geotechnical in situ tests such as pressure meter test. More sophisticated tests such as resonant column test and cyclic triaxial test have been also used for this purpose. The experimental program described soil behaviour as being nonlinear. This observed behaviour permitted to propose an approach of characterizing the behaviour of soil incase if the needed information is only partial. This thesis manuscript presents a data synthesis of different types of in situ and laboratory tests which allowed describing soil shear modulus evolution for different ranges of deformation
Laplaze, Laurent. "Approche moléculaire de la mise en place de la symbiose actinorhizienne." Montpellier 2, 1999. http://www.theses.fr/1999MON20070.
Ovono, Ovono Delavand. "Recyclabilité des alliages d'aluminium de fonderie : Influence des éléments résiduels sur la microstructure et le comportement mécanique." Compiègne, 2004. http://www.theses.fr/2004COMP1549.
Cast aluminium alloys make popular candidates for automotive applications and in particular on the fabrication of cylinder head and engine block materials. For the development of a new cylinder head and in order to lower the costs of provision at the refiner, we have chosen to increase the iron, manganese, and zinc contents used in AS7U3G alloys. The effect of residual element on the microstructure and mechanicals properties of two cast aluminium alloys, the reference AS7U3G and the AS9U3G with a high content in residuals elements, in T5 state, has been studied. Fatigue, tensile, and microhardness tests were performed and the test data were analyzed in relation with the evolution of microstructure. The results of tensile and low cycle fatigue tests showed that stresses levels in the two alloys were identical, but some differences appear at the level of precipitation evolution; And the fatigue life defers considerably because of the significant number of intermetallics compounds and volume fraction of pores in the AS9U3G alloy which are fatigue cracks initiation sites
Haidara, Fanta. "Etude des mécanismes de formation de phases dans des films minces du système ternaire Al-Cu-Fe." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30008.
The mechanisms of phase formation in thin films have been studied in the Al-Cu, Al-Fe, Fe-Cu and Al-Cu-Fe systems. Several samples with different compositions have been prepared by sputtering. Aluminium, copper and iron layers were deposited onto oxidized silicon substrates, they were heat treated and characterized by using several techniques. In situ X-ray diffraction and resistivity measurements were used to follow the phase formation. Thermal annealings followed by quenching have also been carried out to get additional information.Differential Scanning Calorimetry and coupled in-situ resistivity and X-ray diffractionmeasurements were performed. The whole results allowed us to suggest a mechanism of phase formation for each sample and by using theoretical models of growth we determined kinetic data on the phase formation
Hamy, Anne-Sophie. "Identification of Factors Predicting Sensitivity or Resistance to Neoadjuvant Chemotherapy in Breast Cancer Neoadjuvant treatment : the future of patients with breast cancer Neoadjuvant treatment for intermediate/high-risk HER2-positive and triple-negative breast cancers: no longer an “option” but an ethical obligation Long-term outcome of the REMAGUS 02 trial, a multicenter randomised phase II trial in locally advanced breast cancer patients treated with neoadjuvant chemotherapy with or without celecoxib or trastuzumab according to HER2 status BIRC5 (survivin) : a pejorative prognostic marker in stage II/III breast cancer with no response to neoadjuvant chemotherapy Beyond Axillary Lymph Node Metastasis, BMI and Menopausal Status Are Prognostic Determinants for Triple-Negative Breast Cancer Treated by Neoadjuvant Chemotherapy Pathological complete response and prognosis after neoadjuvant chemotherapy for HER2-positive breast cancers before and after trastuzumab era: results from a real-life cohort The presence of an in situ component on pre-treatment biopsy is not associated with response to neoadjuvant chemotherapy for breast cancer Chemosensitivity, tumor infiltrating lymphocytes (TILs), and survival of postpartum PABC patients treated by neoadjuvant chemotherapy Lymphovascular invasion after neoadjuvant chemotherapy is strongly associated with poor prognosis in breast carcinoma New insight for pharmacogenomics studies from the transcriptional analysis of two large-scale cancer cell line panels Biological network-driven gene selection identifies a stromal immune module as a key determinant of triple-negative breast carcinoma prognosis A Stromal Immune Module Correlated with the Response to Neoadjuvant Chemotherapy, Prognosis and Lymphocyte Infiltration in HER2-Positive Breast Carcinoma Is Inversely Correlated with Hormonal Pathways Stromal lymphocyte infiltration after neoadjuvant chemotherapy is associated with aggressive residual disease and lower disease-free survival in HER2-positive breast cancer Interaction between molecular subtypes, stromal immune infiltration before and after treatment in breast cancer patients treated with neoadjuvant chemotherapy COX2/PTGS2 Expression Is Predictive of Response to Neoadjuvant Celecoxib in HER2-negative Breast Cancer Patients Celecoxib With Neoadjuvant Chemotherapy for Breast Cancer Might Worsen Outcomes Differentially by COX-2 Expression and ER Status: Exploratory Analysis of the REMAGUS02 Trial Comedications influence immune infiltration and pathological response to neoadjuvant chemotherapy in breast cancer." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS129.
Neoadjuvant chemotherapy (NAC i.e. chemotherapy before surgery) is increasingly being used for aggressive or locally advanced breast cancer (BCs). Beyond clinical benefits, it represents an opportunity to monitor in vivo sensitivity to treatment. Based on the analysis of datasets of BCs patients treated with NAC, we aimed at identifying mechanisms associated with resistance or sensitivity to treatment.In the first part, we evaluated biological, clinical, pathological and transcriptomic patterns. We demonstrated that unexplored pathological features such as post-NAC lymphovascular invasion may carried an important prognostic information.In a second part, we analyzed impact of imune infiltration in BC and we described extensively the changes of tumor infiltrating lymphocytes (TILs) between pre and post-NAC samples. We showed that the prognostic impact of TILs was different before and after NAC, and was opposite in TNBC and HER2-positive BCs. Finally, we investigated the impact of comedications use during NAC. We found both positive effects - while enhancing immune infiltration and response to treatment - and negative effects with deleterisous oncologic outcomes in specific patients subgroups. In conclusion, the neoadjuvant setting represents a platform to both generate and potentially validate research hypotheses aiming at increasing the efficacy of treatment. The public release of real-life datasets of BC patients treated with NAC would represent a major resource to accelerate BC research
Struski, Stéphanie. "Intérêt de l'hybridation génomique comparative pour la caractérisation de déséquilibres chromosomiques tumoraux : application à des lignées cellulaires chimiorésistantes." Reims, 2001. http://www.theses.fr/2001REIMM204.
Acquired chemotherapy resistance is a major problem in the treatment of many human cancers. This process is difficult to assess because mechanisms of resistance often implicate a panoply of genes. The Comparative Genomic Hybridization identifies quantitative abnormalities present in a genome. CGH interest is thus evident for the targeting of amplified or deleted genes, as testify the review of literature presented in this work. After the optimization of the CGH, we applied it to different chemoresistant tumor cell lines: a ALL-T cell line resistant to vinblastine, mediated by the classical way of P-gp/MDR1; 3 lung adenocarcinoma cell lines resistant to increasing concentrations of etoposide, implicating some process independent to the P-gp way; and finally, 4 ovarian adenocarcinoma cell lines presenting a resistance to various concentrations of vincristine, and a loss of tumorigenicity properties. The CGH reveals new chromosomal loci in these tumor chemoresistant genomes
Millot, Coraline. "Multi-scale characterization of deformation mechanisms of bulk polyamide 6 under tensile stretching below and above the glass transition." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0028/document.
Mechanical properties of bulk polyamide 6 (PA6) have been studied in relation to microscopic deformation mechanisms. By applying various thermal treatments, sets of samples with different semi-crystalline microstructures, namely various crystalline allotropic forms (denoted α, γ and β) and different values of the crystallinity index (from 24 to 35%) and of the long period of the lamellar stacks (from 7 to 12 nm), have been obtained, for two different molecular masses. Mechanical properties have been measured in the linear (viscoelastic) and nonlinear (plastic) regimes below and above the glass transition of the amorphous phase (Tg). Differences of behavior have been observed depending on the microstructure. While the crystallinity index seems to be the predominant factor affecting the mechanical behavior above Tg, other structural parameters such as the crystalline form and the lamellar morphology (thickness and aspect ratio) have to be taken into account below Tg. Deformations at the scales of lamellar stacks and of the crystalline unit cell have been characterized by small and wide angle X-ray scattering (SAXS and WAXS) performed in-situ during tensile tests. In samples with predominantly β phase, lamellae tend to orient perpendicular to the tensile direction (TD). This orientation mechanism (which we denote as ‘Chain Network model’) is driven by the amorphous chains which transmit the stress between adjacent lamellae. The tensile strain in lamellar stacks perpendicular to TD is lower than the macroscopic tensile strain, which must be compensated by increased shear in inclined stacks. Also, at high extension ratios, the β phase transforms into α phase. In samples with predominantly α phase and above Tg, morphology changes are more complex. In a first step, chains orient perpendicular to TD, which implies that lamellar planes tend to orient parallel to TD, possibly due to their high aspect ratio (denoted as ‘Rigid Lamella’ model). In a second step, beyond the yield, a major fraction of crystallites then reorients normal to TD, i.e. chains themselves become parallel to TD, while a minor fraction remains oriented along TD. A highly oriented fibrillar morphology is ultimately obtained in all cases
Alia, Adem. "Comportement à la rupture d'un composite à fibres végétales." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI016.
The objective of this thesis is the characterization of the mechanical behavior and the damage of a woven jute / polyester composite. natural fibers are indeed an interesting ecological alternative to synthetic fibers, in particular glass fibers which are the most used for composite manufacturing. The studied composite is developed in the LMNM laboratory at IOMP, Sétif, Algeria. Two fibre orientations ([0] 8 and [+ 45 / -45] 2S) are considered. The mechanical characterization is carried out in monotonic tensile and compression as well as in cyclic fatigue. Mechanical and microstructural characterizations are carried out in the MATEIS laboratory. The study of the damage is carried out by combining five techniques: the evolution of mechanical parameters via cyclic and fatigue tests, microscopy, acoustic emission (EA), image correlation and micro- RX tomography. The study of the evolution of the mechanical parameters combined with the global analysis of the AE provides first indicators concerning the development of the damage during the tests. Microstructural analyzes allow to finely identify the damage mechanisms that occur during mechanical tests (fiber / matrix decohesions, matrix cracks and fiber breakage). For the segmentation of acoustic emission signals in monotonic tests, an unsupervised classification is used, emphasizing the choice of descriptors and the labeling of the classes obtained. Tensile tests instrumented by image correlation as well as in situ tensile tests under tomography allow to identify the chronology of appearance of the damage. These results are also used to label the obtained classes . The labeled signals are then used to create a library to identify the chronology of evolution of the modes of damage in cyclic fatigue achieved by supervised classification. Finally, all these analyzes made it possible to establish damage scenarios for the different damage modes and for the two orientations. It is thus possible to reconsider the development to optimize the mechanical properties
Jouni, Fatina. "Synergistic interaction earthworm-microbiota : a role in the tolerance and detoxification of pesticides?" Thesis, Avignon, 2018. http://www.theses.fr/2018AVIG0699/document.
Pesticides used to protect plants from pests, threat grievously non-target organisms such as earthworms. Due to their feeding and burrowing activities, earthworms are in direct contact with soil particles and microorganisms, as well as pollutants including pesticides. This work investigated (1) the effect of an organophosphate “ethyl-parathion” on the sensitivity of two endogeic earthworms’ species, Aporrectodea caliginosa and Allolobophora chlorotica; and (2) the role of the gut-microbiota, in synergy with the earthworm’s detoxification pathways, in pesticide tolerance or detoxification. In the first part, biochemical and behavioral responses showed that A. caliginosa is more sensitive to “ethyl-parathion” exposure than A. chlorotica. The endpoints measured ranged from physiological (weight), biochemical (AChE, CbEs, GST) to behavioral biomarkers (cast production and burrowing activity). Our findings showed that the sensitivity of A. caliginosa could be mainly due to the intrinsic sensitivity of its AChE to “ethyl-parathion”. The role of the carboxylesterases, acting as bioscavenger of OP, and the role of the detoxifying enzymes GST did not appear to be efficient mechanisms involved in A. chlorotica tolerance. In the second part, we aimed to characterize the microbiome within the ingested soil, the cast and the gut tissue of A. caliginosa and A. chlorotica in control or polluted soils. Our results showed differences in the microbial composition between these compartments. In this line, we suggested that these two earthworms’ species harbor a species-specific microbiome in their gut. In particular, our findings showed that the earthworm’s gut acts as a “biological filter” for ingested microbial communities during the gut passage. At the level of the gut, we identified four dominated genus within the gut of A. caliginosa versus two dominated genus in the gut of A. chlorotica. Notably, we identified a Rhodococcus strain, which is highly abundant in the gut of A. chlorotica. Previous studies reported Rhodococcus strains for their ability to degrade some group of pesticides. We suggest that the presence of this strain could contribute to the tolerance of A. chlorotica. Finally, we showed that the effect of ethyl-parathion on soil enzyme activities mainly depend on soil texture rather than the presence and/or the species of earthworms. According to our findings, it is of considerable importance to include more than one species to assess toxicity from organophosphorus insecticides, due to the interspecific differences that can occur within the same ecological category. Moreover, the identification and the functional analysis of the microorganisms found in the earthworm’s gut and able to intervene in pesticide detoxification could enhance our knowledge about the fate of the pesticide inside the organism, and could be an important tool for bioremediation program
Lallemand, Florent. "Etude des propriétés thermiques électriques et mécaniques des couches minces de polysilicium dopées in situ phosphore déposées par LPCVD sur des structures à fort rapport d'aspect." Caen, 2009. http://www.theses.fr/2009CAEN2039.
PICS technology (Passive Integration Connective Substrate) allows high integration of passives components onto a silicon substrate and more specifically high density trench capacitors formed by etching of high aspect ratio 3D structures. One of the most critical steps of this process consists in filling 3D structures with an in-situ doped polysilicon layer. Preliminary experiments performed during the development of the second PICS generation have revealed that the tridimensional structures cause an important degradation of deposited films uniformity (thickness and doping). Furthermore, the filling of such 3D structures with polysilicon is inducing wafer warpage that could lead to wafer breakage. In this thesis, studies aimed at solving these two related issues by tuning deposition and crystallization parameters in order to fit the process specifications. Experiments have demonstrated that wafer warpage is closely related to the crystal phase deposited, even after layer re-crystallization at high temperature. First experiments have shown that the best deposition conditions for a good layer uniformity generate damage of the 3D structures. So, new process conditions for deposition and annealing of the polysilicon layer have been developed to limit wafer warpage without degrading uniformity and productivity. Physical, electrical and structural characterizations have shown the correlation of electrical performances improvements with the microstructure of the layer
Medina, Elise. "Synthèse de revêtements anticorrosion par voie sol-gel pour la protection de l’alliage 2024 T3. Caractérisation par spectroscopie d’impédance électrochimique et ellipsométrie in situ." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS673.
Aluminum alloy 2024 T3 is widely used in the aeronautical field due to its high weight-to-strength ratio. However, such material is particularly sensitive to corrosion because of its heterogeneous structure. To protect these alloys, the current strategy is to use a three layer stack doped with CrVI based corrosion inhibitors. Nevertheless, those substances are highly toxic. Therefore, their replacement has become a critical issue for the aircraft industry. In this context, synthesis and characterization of new protective coatings are particularly important. The objective of this work is thus to study materials evolution and corrosion phenomena using in situ ellipsometry and electrochemical impedance spectroscopy. Coupling those tow techniques provides new insights to understand the relationship between coating synthesis, microstructure, durability and anticorrosion properties. On one hand, a study has been done on hybrid hydrophobic layers to enhance barrier properties. On the other hand, mesostructured layers, potential matrix for anticorrosion inhibitors have been studied. The final goal is to couple those two materials in a multi-layer system in order to optimize anticorrosion properties
Evin, Harold. "Low Cr alloys with an improved high temperature corrosion resistance." Thesis, Dijon, 2010. http://www.theses.fr/2010DIJOS082/document.
The improvement of high temperature oxidation resistance of low chromium content steels, such as T/P91, is of great interest in regards with their application in thermal power generating plants. Indeed, they possess good creep properties, and low thermal expansion coefficient. Important needs in energy together with environmental issues place power generation plants under constraints which lead to develop high efficiency systems. A usual way to increase the efficiency consists in increasing temperature and pressure parameters of the power generating plant. Studies has shown that the total efficiency of a plant increases by nearly 8 % when changing the steam parameters from 538°C/18.5 MPa to 650°C/30 MPa. Then, the problem of corrosion resistance of 9% chromium steel in those conditions is asked. In this work, the behavior of a ferritic / martensitic 9% chromium steel has been studied at 650°C in dry air and in water vapor containing environment in both isothermal and thermal cyclic conditions. The weight gain of samples provides information on the kinetics of the oxidation reaction and the adhesion of formed oxide scale. Corrosion products were characterized by several analytical techniques in order to identify oxides with accuracy and to understand their formation mechanisms. Mixed iron and chromium oxides (Cr, Fe) 2O3 are initially formed and provide temporary protection to the substrate. For long time exposure or temperatures above 650°C, magnetite, Fe3O4 and hematite Fe2O3 are the main oxides formed, highlighting the fact that low chromium steel are inappropriate for applications in such drastic conditions. In order to increase the high temperature corrosion resistance of this alloy, various solutions have been proposed as aluminizing by pack cementation, reactive element oxides coatings of by MOCVD, or addition of alloying elements in the steel composition. These solutions were then tested at 650 ° C in dry air and in water vapor environments
Dubille, Matthieu. "Transport solide et abrasion dans les rivières à fond rocheux.De la mesure au modèle sur un exemple himalayen." Phd thesis, 2008. http://tel.archives-ouvertes.fr/tel-00361017.
Au travers des plis de l'avant pays himalayen que nous avons choisis comme « laboratoire naturel », dans les Siwaliks du Népal Central, l'abrasion fluviatile annuelle a atteint localement plusieurs millimètres voire dizaines de millimètres en 2006. Nous proposons un modèle simple intégrant les caractéristiques des flux et les l'érodabilités des roches permettant de reproduire assez fidèlement les valeurs d'érosion mesurées sur le terrain (à l'échelle d'une section de chenal). Ce mémoire est également l'occasion d'avancées méthodologiques, notamment sur la mesure indirecte de la charge de fond (granulométrie sur image des séries conglomératiques, désagrégation des grès) et sur la mesure de « l'érodabilité » des roches directement sur le terrain grâce au rebond du marteau de Schmidt. Nous présentons enfin de nouveaux dispositifs autonomes de mesure en continu dont un « capteur d'érosion » très prometteur.