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École doctorale Ingénierie - matériaux mécanique énergétique environnement procédés production (Grenoble)

Overview
Works: 1,191 works in 1,206 publications in 2 languages and 2,114 library holdings
Roles: Other, Degree grantor, 996
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Most widely held works by École doctorale Ingénierie - matériaux mécanique énergétique environnement procédés production (Grenoble)
Procédés de séparation membranaire pour la production en continu de nanocristaux de polysaccharides : approche expérimentale et modélisation by Ahlem Romdhane( )

2 editions published in 2014 in French and held by 3 WorldCat member libraries worldwide

The current work investigates the use of cross flow microfiltration using ceramic membrane to fractionate the heterogeneous suspension obtained after starch hydrolysis in order to isolate starch nanocrystals. The final aim is to evaluate the possibility of coupling the filtration step to the hydrolysis step in a single production loop in order to enhance the starch nanocrystal production yield. The characterizations of the suspension (particle size and charge) obtained with the classic production process indicates that it was a mixture of starch nanocrystal aggregates and starch residues, individualized starch nanocrystals represent only 5 % of the initial starch. The fractionation study was done using two pilot plans, in a dead end configuration at laboratory scale (plate membrane) and in a cross flow configuration at semi-industrial scale (tubular membrane). Design of experiments methodology was used to optimize the fractionation efficiency when filtering a neutral suspension considering the effect of filtration parameter on the transmission yield and membrane fouling. In the optimized condition, it was possible to recover 25 % of starch nanocrystals while keeping the permeate flux at its highest value. Mean diameter of the recovered particle was less than 300 nm. At this condition, it was also possible to recover the starch nanocrystals directly from the acidic mixture obtained at the end of the hydrolysis step. The analysis of fouling mechanism using dead end filtration experiments highlights that membrane fouling occurs because a cake bult up at the membrane surface. This study investigates also the use of ceramic ultrafiltration membrane in a diafiltration process in order to purify the acidic suspension from soluble molecules without modifying particle size distribution which is a promising technique for a large scale production
Optimisation des procédés d'impression dédiés à la production de masse de composants microélectroniques by Rita Faddoul( )

2 editions published in 2012 in French and English and held by 3 WorldCat member libraries worldwide

This work demonstrates the printing processes potential for manufacturing ceramic based electronic devices. Several printing techniques were studied: screen printing, flexography, rotogravure and inkjet. Ceramic tapes surface properties were characterised: surface pore size, roughness and surface energy. These analyses allowed the selection of the inks raw materials adapted to the substrates and the printing processes. Water-based silver inks were formulated. Inks properties, rheology and surface tension, were analysed and their effect on line properties was investigated. Printed substrates were afterwards sintered. Resistivity values close to that of bulk silver were reached (2 to 12x10-8 Ohm.m). These work novelties are mainly the formulation of water-based environmentally friendly screen printing pastes and the flexography printing of silver inks onto ceramic substrates. This study offers new perspectives for the industrialisation and the mass production of electronic components on flexible ceramic substrates
Conception d'étiquettes autoadhésives par microencapsulation d'adhésif by Robin Abderrahmen( )

2 editions published in 2012 in French and held by 3 WorldCat member libraries worldwide

The main objective of this investigation is to prepare innovative silicone liner-free labels. It can be achieved by the adhesive 'self protection', thanks to its incorporation into microcapsules. This allows the preparation of 'dry labels' gluing under the application of a pressure, which induces the rupture of the microcapsules, thus releasing the core material, a pressure sensitive adhesive. The first step was to analyse 3 water-based PSA in view of their encapsulation. Then, the most suitable adhesive was microencapsulated by coacervation (using biopolymer as shell) and by in situ polymerisation. Two other encapsulation processes (spray-cooling and spray-drying), were also carried out at the LAGEP and were compared with the 2 former processes. Coating colour formulations were prepared with spray-cooling microcapsules (the most adhesive ones). Coating trials were carried out with a Meyer rod, and by screen printing. Compatibility between microcapsules and the label making process, using a flexographic printing press, was determined. Finally, the mains characteristics of the prepared innovative products (adhesion, application pressure) were compared to industrial self-adhesive homologues, and found that they could be suitable for the preparation of silicon liner-free envelops and stamps
Caractérisation physique de la microstructure des interconnexions avancées Cu/Low-k pour l'étude des défaillances par électromigration by Romain Galand( )

2 editions published in 2011 in French and held by 3 WorldCat member libraries worldwide

L'electromigration est identifiée comme la principale cause de dégradation des interconnexions en cuivre limitant ainsi la fiabilité des produits issus de la microélectronique. Dans ces travaux nous proposons d'approfondir notre connaissance de ce phénomène en étudiant le lien qu'il présente avec les paramètres morphologiques du cuivre. Dans ce but, la technique de diffraction des électrons rétrodiffusés est utilisée. Nous avons d'abord développé les méthodes de préparation et d'acquisition nécessaires afin de pouvoir caractériser les structures issues des technologies 45 nm et au-delà que nous avons choisies pour cette étude. Un lien entre les joints de grains de forte désorientation et la localisation des cavités a alors pu être mis en évidence. Nous avons ensuite tenté de modifier la microstructure du cuivre pour impacter la fiabilité sans succès. Finalement, c'est l'intégration de nouveaux matériaux (Al, Co) renforçant l'interface supérieure, chemin de diffusion du phénomène, qui semble être la voie à adopter pour améliorer la résistance des lignes à l'électromigration
Modélisation et simulation de l'atelier de régénération de l'usine Kraft by Jean-Baptiste Picot( )

2 editions published in 2012 in French and held by 3 WorldCat member libraries worldwide

L'atelier de régénération d'une usine kraft permet d'extraire des liqueurs noires les élémentschimiques nécessaires à la cuisson du bois et de les régénérer sous leur forme active, ainsi quede valoriser la fraction organique dissoute sous forme de chaleur. Les opérations unitaires enoeuvre sont nombreuses, complexes, et souvent mal décrites. Ce travail vise à permettre unemeilleure compréhension de la régénération, par la réalisation de modèles fiables décrivant lesphénomènes et processus dans chaque opération unitaire, leur implémentation algorithmiqueet leur exploitation par la simulation du procédé global
Etude du cloquage de films minces élastoplastiques sur substrat rigide by Nadia Ben Dahmane( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Thin film coatings submitted to high compressive stresses may experience a simultaneous buckling and delamination phenomenon called "blistering". The mechanism of formation and propagation of blisters in the form of straight wrinkles and circular blisters has been extensively studied in the literature considering a linear elastic behavior for the film. However, the effect of plasticity on the propagation and mechanical equilibrium of such blisters, although experimentally observed, had not been systematically studied to date.In this work, we are interested in the observation and characterization of buckling structures observed on gold films deposited on silicon substrates. The effects of plasticity on the morphology or critical buckling load of buckled structures are quantitatively demonstrated using small scale surface observation techniques such as AFM, as well as mechanical testing by nanoindentation tests and stress measurement methods.A mechanical model is developed in order to model the film as a geometric nonlinear plate with elastic-plastic behavior in unilateral contact with a rigid support representing the substrate. In addition, a cohesive zone model is introduced between the plate and the support in order to take into account the delamination of the film, with a separation work depending on the mode mix of the interface loading.This model allowed us to highlight the effect of plasticity on the equilibrium profiles resulting from elastic-plastic blistering, for both straight and circular blisters morphologies. The effect on the offset of the critical buckling load has also been studied. Finally, the influence of plastic deformation on the propagation mechanism of the interfacial fracture itself has been studied. In particular, a stabilizing effect of the circular blister form, which has been observed experimentally in various studies, has been demonstrated through calculation
Sur la prise en compte de la qualité environnementale des produits dans la conception des chaines logistiques vertes by Imen Nouira( )

1 edition published in 2013 in French and held by 2 WorldCat member libraries worldwide

Les enjeux environnementaux impactent de plus en plus le comportement des clients ainsi que les stratégies des entreprises. Dans ce contexte, l'optimisation de la chaine logistique en tenant compte des questions environnementales devient un enjeu critique. Dans cette thèse nous nous intéressons à cette problématique. Une originalité de ce travail est de montrer que les décisions prises lors de la conception d'une chaine (localisation des sites, choix des processus de production, de transport,...) ont une influence sur la qualité environnementale d'un produit perçue par les clients, et influent donc sur le niveau de la demande et/ou prix de ces produits. La demande et le prix ne sont plus des variables exogènes comme pratiquement toujours considéré dans les travaux existants, mais bien des variables endogènes. Dans cette thèse nous proposons alors des modèles d'optimisation des activités logistiques en tenant compte de la qualité environnementale des produits élaborés et des préférences clients. Nous montrons grâce à des expérimentations sur un cas d'étude du secteur de textile, la pertinence de la considération de la qualité environnementale des produits dans les modèles d'optimisation des activités logistiques
Experimental analysis of the confined behavior of concrete under static and dynamic shear loading by Reem Abdul rahman( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

This PhD thesis focuses on studying the confined behavior of concrete under shear loading in static and dynamic conditions. An experimental method based on the Punch-Through Shear (PTS) test is used in order to investigate shear behavior in mode II conditions. The concept of this test is to first subject the specimen to a confining pressure and then an axial loading is applied to punch through the central portion of the core.In order to introduce confinement to the concrete sample prior to testing it under shear, two methods have been used. The first one is an active confinement applied by means of a high capacity triaxial press Giga. The second method consists in confining the sample with a pre-stressed metallic cell instrumented with hoop strain gages in order to evaluate the confinement acting in the ligament of the concrete sample.Samples confined with the pre-stressed cell are subjected to two types of loading; static and dynamic. The static tests are carried out by means of a normal hydraulic press while dynamic shear testing are performed using a modified Split Hopkinson Bar setup which allows to determine the shear response of concrete over a wide range of strain-rates.The results of test campaigns show that the shear strength of the concrete increases significantly with an increase of confining pressure. Furthermore, dry and saturated concrete samples have been tested in order to study the influence of saturation ratio on the shear behavior of concrete. The results show a higher shear strength with dry samples than in wet ones. Moreover, a small influence (compared to what was observed in dynamic tension) of the strain rate was observed. A high performance concrete was also studied to investigate the influence of concrete composition on its shear strength. It was observed that its shear strength strongly exceeds that of the ordinary concrete. The obtained results are compared with data from literature obtained with different experimental methods
Développement et compréhension des mécanismes électrochimiques des accumulateurs Lithium-ion/Soufre by Alice Robba( )

1 edition published in 2018 in French and held by 2 WorldCat member libraries worldwide

Melt processing of cellulose nanocrystals : thermal, mechanical and rheological properties of polymer nanocomposites by Malladi Nagalakshmaiah( )

1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide

The low thermal stability and irreversible agglomeration issues are limiting to process the polymer nanocomposites using CNC as the reinforcing phase. In this context, thermally stable and highly dispersed CNC were prepared by green process (Aqueous based methods) like physical adsorption and surface modification. These two different Extrudable CNC was reinforced in to hydrophobic polymers. Ensuing polymer nanocomposites had a positive impact on the storage modulus, tensile strength, Young's modulus. Importantly, no evidence of micro aggregates in the matrix was observed in the scanning electron microscopy images contrary to non-treated CNC. Both the surface modification and adsorption are the water based methods and is an industrially viable solution. Also, it can be applicable at industrial level
Optimisation de la préparation de commandes dans les entrepôts de distribution by Nicolas Lenoble( )

1 edition published in 2017 in French and held by 2 WorldCat member libraries worldwide

The order picking is a critical activity in distribution warehouses (60% of the operational costs in traditional warehouses). One way to reduce these costs is to collect several orders simultaneously, rather than individually, to avoid unnecessary travels to the operators in the case of manual picking of the products, and less workload for the machines, in the case of automated picking. We consider, in this PhD, warehouses where products are stored in automated storage systems composed by trays on which products are stored. We consider two types of machines: VLMs and Carousels. These two types differ by the time required to move from a tray to the next one to visit (constant in the case of a VLM, depending on the number of trays between 2 consecutively visited trays for the carousels). We aim to develop order batching methods in automated warehouses to collect a set of orders efficiently, according to criteria that we will define.We study a first category of order batching, for which each batch will be entirely collected (all orders associated with a given batch will be collected) before moving to the next batch. We evaluate completion time, when the operator does the picking on one or several machines. The interest of using multiple machines is to search trays in masked time (the machine change trays while the operator is busy to collect on other machines). From this evaluation of the completion time, we extract an optimization criterion and establish optimization models for the VLMs then the carousels. These models are then tested with actual data, thanks to the partnership with the company KLS Logistic, editor of the WMS Gildas. Finally, we extend the resolution to metaheuristics, to ensure good solutions under reasonable computation time. Significant savings in terms of completion time reduction justifies the interest of our work.We then study the second category, where a set of orders is collected simultaneously, but unlike the previous case, whenever an order is collected, it is immediately replaced by a new one. We'll talk here about "Rolling batching”. This approach is typically used in the "Drive-in shops". We develop an algorithm for the computation of the waiting time of the operator. Resolution coupling heuristics and a metaheuristic is proposed in order to effectively resolve the order sequencing. Significant gains are achieved by the use of the proposed method
Stockage d'énergie thermique par changement de phase - Application aux réseaux de chaleur by Matthieu Martinelli( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

This study is about a shell and tubes latent heat thermal energy storage system. This system is expected to be integrated in a district heating network substation. Heat transfers inside the PCM as well as convection flow regime inside the heat transfer fluid are investigated.A first experimental study aims at demonstrating the necessity of internal insert inside the tubes in order to avoid mixed convection flow regime. Two highly finned tubes as well as two inserts are tested. Inserts are either cylindrical or helical. Better thermal performances are obtained with the helical one. Besides, it is shown that free convection, between the fins is negligible. Effective thermal conductivities are estimated with an experimental and analytical approach at 7.4 and 10.9 W/m/K for the 7 fpi and the 10 fpi tube.A second test campaign is carried out with metallic foams. The first one is stochastic and in copper while the second one is regular and in alumina. Effective thermal conductivities are around 13.4 and 39.4 W/m/K respectively. The copper foam heat exchanger is shown to be better than a copper finned tube in terms of stored energy and thermal power, whereas only half the mass of the fins is used in the foam.Eventually a CFD numerical model is experimentally validated. This model shows that free convection inside the PCM is negligible on the overall thermal performances even though it modifies the solid/liquid interface shape locally
Méthodologie d'éco-conception orientée utilisation by Lucie Domingo( )

1 edition published in 2013 in French and held by 2 WorldCat member libraries worldwide

En intégrant le cycle de vie d'un bien dans son processus de développement, l'éco-conception permet d'améliorer la performance environnementale de ce futur produit. La combinaison, dans cette thèse, des notions de la conception centrée utilisateur et de la pensée cycle de vie, permet de proposer une méthode pour l'intégration de la phase d'utilisation en éco-conception. La méthode repose sur la proposition de nouveaux modèles pour représenter l'utilisation adaptés aux spécificités de l'éco-conception. A partir du modèle de produit, un modèle de la phase d'utilisation, connectée aux phases de distribution et de fin de vie, permet d'associer l'utilisation du produit à son cycle de vie complet. Le modèle de contexte permet de positionner la performance environnementale du produit en utilisation par rapport à des paramètres associés à l'utilisateur et à l'environnement d'utilisation. L'évaluation environnementale du scénario d'utilisation regroupant tous ces modèles permet d'adapter les stratégies d'amélioration de la méthode à l'utilisation d'un produit en conception. Une application de la démarche à la re-conception d'un réfrigérateur pour la France et le Brésil permet d'illustrer le fonctionnement de la méthode
Caractérisation photoélectrochimique des oxydes formés sur alliages base nickel en milieu primaire des réacteurs à eau pressurisée by Abdelhalim Loucif( )

1 edition published in 2012 in French and held by 2 WorldCat member libraries worldwide

In this thesis, we are interested in semiconducting properties of oxides formed on nickel base alloys. The aim is to demonstrate the effects of hydrogen partial pressure, the nature of the alloy and the surface conditions on the semi-conduction type and the band gap energies. Photoelectrochemical technique was used to characterize the semiconducting properties. Other complementary techniques were also used such as FEG-SEM, X-ray diffraction, Raman spectroscopy and XPS. Corrosion tests were performed in simulated primary medium (titanium autoclave, temperature 325°C, duration 500 hours). Samples of alloys 600 and 690 of 1 µm diamond polishing were oxidized at P(H2) < 0,01 ; 0,3 et 6,5 bar. The surface conditions concerned only the alloy 600 oxidized at P(H2) = 0,3 bar. We used a new method for fitting energy spectra to obtain the band gap energies. The obtained results show that only the hydrogen pressure affects the semiconducting type of oxides presented by the high energies, it shift from n-type (P(H2) < 0,01 bar) to insulating type (P(H2) = 0,3 and 6,5 bar). An n-type behavior was recorded at low energy whatever the study parameters. Band gaps energies of NiO, Cr2O3 and NiFe2O4 were revealed
Turbulence de grille oscillante à basses températures by Ndeye Fatimata Issaga Sy( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

This thesis aims at comparing the isothermal turbulence in Helium I (HeI, classical fluid) and in Helium II (HeII, which has one inviscid component) through a Lagrangian analysis. Analogies and/or differences between the classical and superfluid behaviors are expected to shed new light on the intrinsic multi-scale properties of turbulence. This is a pioneering study, as no similar cryogenic experiment had been performed prior to this thesis, which opens a full range of possible future studies (as an example, similar measurements of Lagrangian tracking in the wake of an oscillating cylinder, are currently in progress at Charles University in Prague). We opted for an oscillating grid turbulence generation, which produces isotropic and homogeneous (per plane) turbulence, with no mean velocity (hence allowing longer observation times). As tracers we use hollow glass microspheres, which are almost neutrally buoyant in liquid Helium. This being a new facility, significant effort was dedicated to the design and the tailoring of the experiment, its implementation and the calibration of the flow. The cryostat hosting the experiment is fully transparent (made of glass), allowing visualization at multiple angles. Measurements were performed using high speed imaging in backlight illumination. Particle trajectories were reconstructed using Lagrangian tracking, from which we performed analysis of single particle statistics (single time and two times) as well as relative dispersion of pairs of particles. The spatial and temporal resolution of our measurements give us access to the dynamics of the flow at inertial scales, while dissipative scales are marginally resolved. In these conditions, we find that turbulence in HeI behaves in agreement with previous results obtained in similar flows using classical fluids. Interestingly, the same turbulence properties stands also for superfluid conditions
Croissance de la céramique eutectique Al₂O₃-YAG-ZrO₂∶Y et étude de la microstructure Chinese Script by Maya Cherif( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

These last decades, directionally solidified eutectic oxides have drawn attention and are seen as an alternative to Ni based superalloys for the development of high temperature turbine blades. Indeed, their 3D entangled and complex microstructure, called Chinese Script and the high quality of the interphases provide a thermal stability and mechanical properties, creep and strength, constant up to 1973 K.Our study focuses on the directional solidification of an alumina-based ternary eutectic alloy. The work is based on two approaches, experimental and modeling, in order to understand two inherent aspects of this alloy morphology: -The Chinese Script microstructure composed of irregular entangled lamellas of the two major phases Al2O3 and YAG and the third phase ZrO2:Y. - Colonies formation due to the presence of an impurity causing an interface destabilization.Experiments have been performed by different growth techniques: EFG, Bridgman and Micro-Pulling down exploring a large range of growth conditions. The modeling of these processes on a commercial software COMSOL gave the precise knowledge of the growth rate and the temperature gradient, needed for the study of the growth mechanisms. In the meanwhile, samples' composition has been confronted to the phases equilibrium diagram calculated by the CALPHAD method.A characterization route of the microstructures obtained for different growth conditions has been set up in order to describe this irregular eutectic. Thus, the influence of speed and temperature gradient have been studied, showing identical growth behavior with eutectic metals. Moreover, it appears that this eutectic structure is composed of two single crystals: Al2O3 and YAG and a finely dispersed particles of ZrO2:Y.Finally, a physico-chemical model is presented, based on classical models in the case of metallic eutectics, in order to describe the formation of this microstructure and the appearance of colonies at the eutectic composition. The model is confirmed by the experimental observations. Peculiarities of the ceramic eutectic growth, with respect to metallic eutectics, are discussed.Besides, a way to control the microstructure through an electric field is presented. Indeed, by using the ionic property of the molten material, applying an electric field allows to modify ions transport and thus influences the diffusion phenomena at the origin of the microstructure
In situ nanotomography investigation of cavity nucleation and growth in light alloys during high temperature deformation by Richi Kumar( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

La déformation à haute température induit la germination, la croissance et la coalescence de cavités, domaine très étudié en science des matériaux. Plusieurs modèles théoriques ont été proposés pour prédire la nucléation et la croissance de la cavité mais la comparaison avec l'expérience est limitée. La principale raison en est le manque d'outils de caractérisation appropriés permettant d'étudier in situ la nucléation et la croissance des cavités à haute résolution spatiale (inférieure à 1 µm).Dans le cadre de ce travail, la nanotomographie in situ aux RX a été mise au point pour l'étude des déformations à haute température. Deux dispositifs mécaniques pouvant s'adapter dans un four ont été développés : ceci permet de réaliser une analyse 4D in situ des dommages à haute température (inférieure à 1073 K). De plus, des routines d'acquisition de données à résolutions multiples ont été mises au point, ce qui a permis d'obtenir alternativement des images à haute résolution (100 nm) et à basse résolution (645 nm). Ces développements ont permis l'imagerie 4D de la germination et de la croissance de l'endommagement avec une taille de pixels de 100 nm et un temps de balayage de 7 secondes. Ces données expérimentales ont été comparées aux modèles théoriques par el suivi du volume de chaque cavité.Cette technique a été utilisée pour étudier la nucléation et la croissance des dommages lors de déformations à haute température (7,9 MPa, 698 K), dans un alliage d'Al -3,6% en poids de Cu. Cet alliage modèle permet la génération contrôlée de particules de seconde phase pour favoriser la germination des cavités. Les changements de forme des cavités avec la déformation ont été étudiés. De plus, le changement du taux de croissance volumétrique de la cavité par rapport au rayon équivalent des cavités individuelles a été comparé aux modèles existants de croissance de la cavité par diffusion et plasticité. On a constaté la présence de plusieurs porosités préexistantes dans l'alliage, alors que très peu de germination de cavité ont été observées. Les données expérimentales sur le taux de croissance correspondent bien aux modèles étudiés et il a été conclu que les cavités se développaient initialement par diffusion suivi par une croissance par plasticité.L'utilisation de la nanotomographie in situ a été étendue à l'étude de la nucléation et de la croissance pendant la déformation à haute température (3,2 MPa, 673 K) dans l'alliage commercial AZ31. L'évolution de petites cavités presque sphériques en cavités complexes a été étudiée, en analysant les changements de forme pendant la croissance. Le taux de croissance volumétrique de la cavité a également été calculé et comparé aux modèles de diffusion et de glissement aux joints de grain. Dans un cas particulier, le glissement aux joints de grain a été estimé en suivant les déplacements des intermétalliques qui servaient de marqueurs.Peu de germination de cavité ont été observées au cours de la déformation, par contre les cavités préexistantes, issues du laminage, ont évolué en taille avec la déformation. L'examen des formes des cavités a révélé que la diffusion et le glissement aux joints de grain sont les mécanismes principaux de la croissance. La diffusion dominant la croissance dans les premiers stades (déformation inférieure à 0,3) puis une combinaison des deux mécanismes gouverne la croissance. Le modèle de croissance par diffusion surestime les données expérimentales tandis que les modèles de diffusion restreinte s'ajustent mieux aux évolutions de volume des cavités. Une proportionnalité directe a été observée entre le du grain et la longueur de la cavité dans une cavité où la croissance est dominée par le glissement aux joints de grain. De plus, outre la croissance, une proportion importante de cavités a montré une diminution du volume pendant la déformation. Ceci a été attribué au frittage des cavités sous l'effet de la tension superficielle
Détection et évaluation des fuites à travers les ouvrages hydrauliques en remblai, par analyse des températures réparties, mesurées par fibre optique by Pierre Cunat( )

1 edition published in 2012 in French and held by 2 WorldCat member libraries worldwide

Les fuites au travers des ouvrages hydrauliques en remblai sont les signes précurseurs d'un dysfonctionnementdu dispositif d'étanchéité de l'ouvrage pouvant entraîner leur rupture. La détectionprécoce des fuites et leur quanti_cation est donc primordiale.Les méthodes géophysiques et thermométriques à grand rendement apportent des éléments deréponse pour la détection des fuites, le long des ouvrages à long linéaire, mais l'estimation de leurvitesse, nécessaire à l'évaluation de la dangerosité des fuites, n'est pas encore satisfaisante.Cette étude porte sur la détection et quanti_cation des fuites à travers les ouvrages hydrauliquesen remblai soumis à une charge d'eau permanente. Les méthodes proposées exploitent des mesures detempératures naturelles du sol à l'aide de _bres optiques placées sous le talus amont ou aval.Deux modèles de quanti_cation ont été développés et testés sur les données d'un site expérimentalcontrôlé et d'un site réel. Les résultats obtenus concordent avec les mesures de vitesse e_ectuées surles deux sites
Etude de réalisation de scellement des MEMS par l'alliage eutectique Al-Ge by Victor Lumineau( )

1 edition published in 2018 in French and held by 2 WorldCat member libraries worldwide

Les microsystèmes électromécaniques (MEMS) sont une des révolutions issues de la microélectronique de ces dernières années qui ont permis l'apparition de nouveaux objets connectés à leur environnement tels que les smartphones. Pour répondre entre autres à la problématique de miniaturisation, ces capteurs doivent être assemblés avec les transistors qui les pilotent via des procédés d'intégration en trois dimensions. Les études de la littérature montrent que la brasure à base d'alliage eutectique Al-Ge permet de répondre de ce besoin. Dans le procédé de scellement eutectique Al-Ge, les constituants de l'alliage sont déposés sur au moins une des deux surfaces à coller. La fusion puis la solidification de la brasure va donner lieu à une structure eutectique et fermer mécaniquement l'interface pour former un assemblage. Cependant, des points cruciaux restent encore à approfondir, notamment la fuite de l'alliage liquide en dehors de la zone à coller ainsi que l'apparition de trous à l'interface de scellement.Le but de cette thèse est donc d'étudier dans un premier temps les phénomènes physiques (mouillage, solidification, diffusion) qui déterminent la qualité finale des assemblages. Dans un second temps, ces résultats sont mis à profit pour développer des procédés de scellement hermétiques et avec une bonne tenue mécanique pour l'encapsulation des MEMS. L'étude porte sur l'influence des paramètres tels que la température, l'épaisseur et l'état surfacique des couches, mais également sur les mécanismes de réactivité aux interfaces entre l'alliage liquide et les substrats
Effet de la température sur les hétérogénéités de déformation plastique dans les alliages de magnésium by Thibaut Dessolier( )

1 edition published in 2018 in French and held by 2 WorldCat member libraries worldwide

The aim of this study is to quantify the intra and intergranular contribution of the deformation during a high temperature micromechanical test on a magnesium alloy (AZ31). In order to answer this scientific issue, we have developed an in situ tensile test at high temperature within a SEM. It has required a significant preparation work in order to push the current technical limits of this type of test on magnesium alloy. These technical limits can partly explain why there are currently few in situ studies at high temperature on magnesium alloys. A local marker in the form of a microgrid was placed on our sample as it does not provide any local contrast for digital image correlation (DIC). Before the deposition of the microgrid, EBSD mapping was made. Using the grain boundaries from the EBSD, we can superimpose the deformed grain boundaries on the strain map from the DIC.Using high temperature in-situ tensile tests, we were able to highlight the effect of the temperature on the different active deformation mechanisms. This whole development work enables us to locate the plastic deformation heterogeneities both according to the evolution of the deformation and for several temperatures. From the tests conducted, it has been shown that the higher the temperature, the more heterogeneous the plastic deformation heterogeneities are located in the vicinity of the grain boundaries. Based on a heart/coat hypothesis, we were able to quantify the intra and intergranular contribution, and show that it became more important with temperature
 
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Alternative Names
École doctorale 510

École doctorale Ingénierie - matériaux environnement mécanique énergétique procédés production (Grenoble)

École doctorale Ingénierie - matériaux mécanique énergétique environnement procédés production (Grenoble)

Ecole doctorale Ingénierie, matériaux, mécanique, environnement, procédés (Grenoble)

ED 510

ED I-MEP²

ED IMEP2

ED510

EDIMEP2

I-MEP²

I- MEP2 (Grenoble)

IMEP2

Languages
French (20)

English (5)