Search results for "Éléments"

Le pur, l'impur et l'imaginaire des éléments chez Bachelard

2011

International audience

Contribution to the investigation of dynamic responses of human tissues under high velocity impacts using finite element modeling

2022

Thoracic injuries happen frequently in various frameworks of high velocity impact biomechanics. Rib fractures and lung injuries are the most common hard and soft tissue injuries in human thorax. This thesis aims to contribute to the investigation of dynamic responses of human tissues especially ribs and soft tissues under high velocity impacts using finite element modeling. Firstly, a novel strain-rate-dependent elasto-hydrodynamic constitutive law of the synthetic polymer Styrene-Ethylene-Butylene-Styrene (SEBS) gel was proposed and implemented as a user material subroutine in Radioss (Altair Hyperworks) to interpret dynamic behaviors of SEBS gel under various loading configurations. Numer…

Representations of the world and elementary symbolism

2013

Confronting different philosophical, religious and literary pieces of work, this thesis studies the concept of representation through the use of the four elements: Air, Earth, Water and Fire. Through the similar notions of participation, analogy, fold or flesh which bring up the question of relationship between body and soul, we realize that the representation, or staging, is an obvious way to understand this relationship, and is also, paradoxically, a way for the subject to put a distance between himself and the world. How can we understand this "presence-absence" ambivalence? In order to do it we have to question the relationship between objectivity and subjectivity and furthermore the on…

Modélisation de phénomènes locaux : vers leur prise en compte dans la simulation de la cinétique d'oxydation d'un métal.

2006

The oxidation of metals is a complex process involving several mechanisms that take place at different length scale (macroscopic and microscopic). In this work, we try to integrate local phenomena (microscopic scale) in macroscopic models, especially to the modelling of the metal oxidation kinetics. The study is divided in two parts ; the first one based on non-equilibrium thermodynamics allows us to obtain the evolution laws of the system metal/oxyde, those were used to modelling oxidation kinetics. The second one is microscopic ; it consists in a study of the thermo-mechanical behaviour of various aluminium surfaces by molecular dynamic and the calculation of their surface energy density.…

Interconnecteurs métalliques de piles à combustible de type SOFC - Résistance à la corrosion et conductivité électrique à haute température

2009

The need of interconnect to connect individual cells into electrical series in a SOFC stack appears as one of the most important point in fuel cell technology. The main important criteria requires for interconnect is an excellent oxidation resistance in air and in H2/H2O. The goal of this study is to determine the influence on corrosion behaviour of a reactive element oxide coating (La2O3, Y2O3) realized by MOCVD on different metallic alloys like Crofer22APU, Haynes230 and Fe30Cr. The realisation of long ageing (7 700 and 15 400 hours) proved to be insightful. The corrosion kinetic experiments, the oxide scale characterisation and ASR measurements established that the presence of perovskite…

Etude de la variable fiscale comme facteur de contingence dans la reconnaissance des immobilisations incorporelles

1999

International audience; En pratique, la rubrique "immobilisations incorporelles" pèse peu lourd dans le bilan des comptes sociaux des entreprises françaises. L'un des facteurs explicatifs peut être l'existence de liens théoriques entre la comptabilité et la fiscalité; cette existence conduit, en effet, à une pratique fiscalo-comptable des entreprises en matière de choix comptables ou d'amortissement du fonds de commerce. Cette influence de la variable fiscale sur le traitement comptable des éléments incorporels pose d'ailleurs problème dans le cadre du processus de normalisation internationale.

Ecophysiological and molecular processes involved in water stress memory in pea: from gene expression regulation to plant hydromineral nutrition

2022

Climate change induces increasingly frequent periods of water deficits during the crop cycle. These periods of water stress negatively impact the plant, notably by limiting the availability of resources (water, mineral elements) and by limiting carbon fixation by the plant. In this context, several studies highlighted the beneficial effect of “priming” of a first stress on the response to a second stress by the induction of a transcriptional memory. This memory depends on epigenetic modifications implemented during the first stress. These modifications can regulate the expression of genes known as “memory genes” which have been characterized in the aerial parts of Arabidospsis and maize. Ho…

Prédiction de la contrainte de rupture de composites unidirectionnels et suivi de l'accumulation de ruptures de fibres

2005

Contribution to the modeling of microstructural corrosion on aluminium alloys : definition of a methodology to study the bimetallic corrosion phenome…

2008

The initiation and the propagation of aluminum alloys microstructural corrosion is mainly based on the bimetallic corrosion phenomenon. This type of corrosion is caused by galvanic coupling at a local scale between the different phases contained in the alloy. The description of the localized corrosion phenomenon has been largely studied. Their complexity can explain why they are so difficult to predict by the way of numerical tools and why the works that have been done on this subject are so scarce. The present thesis brings a new contribution to this field by suggesting a methodology based on the complementary use of local electrochemical techniques and the finite element simulation of bim…

Fonctionnalisation de surfaces métalliques par des couches minces d'oxynitrures de titane obtenues par irradiation laser sous atmosphère contrôlée et…

2013

The technological advances in areas such as automotive and aerospace industries require materials capable of withstanding demanding conditions. Surface treatments are effective tools to improve the surface properties of materials while preserving their bulk properties. Besides many conventional processes, laser treatments are efficient methods for hardening and increasing the durability of materials. This work is focused on the growth of titanium oxynitride surface layers by laser irradiation of pure titanium plates with nanosecond pulsed sources. The influence of the laser treatment conditions on the composition and the structure of these surface layers was studied. In particular, for lase…