Search results for "Mécanique"
showing 10 items of 83 documents
Mitochondrial dysfunction and host immune response during pneumococcal pneumonia : impact of mechanical ventilation?
2020
Lung damage induced by mechanical ventilation (MV) worsens the prognosis of pneumonia. Mitochondrial dysfunctions could account for such deleterious effects. Accordingly, data obtained from both in vitro and in vivo experimental studies, as well as in ventilated patients with acute respiratory distress syndrome, show that mitochondrial alarmins, especially mitochondrial DNA, are released in the alveolar compartment as a result of the cyclic stretch, and could thus represent one link between the mechanical insult and the sterile inflammation leading to VILI (ventilator-induced lung injury). In rabbits, we show herein that adverse and prolonged MV worsens the prognosis of pneumococcal pneumon…
Polygalacturonate hydrogels using Fe2+ as cross-linkers : impact of the local association mode on gelation mechanisms, control of the multiscale stru…
2018
This pHD thesis describes the design of polygalacturonate hydrogels (polyGal) cross-linked by the Fe2+ cations, and their experimental characterization from the molecular scales up to the macroscopic scales, by combining EXAFS spectroscopy, Small Angle Neutron Scattering (SANS) and rheological measurements. We designed a robust gelling protocol that allowed to obtain reproducible cylindrical gels with controlled concentration gradients from the lower side to the upper side of the gel. The ratio [Fe]/[Gal] has a constant value all along the gel, which demonstrate that the Fe2+ cations are associated with 4 galacturonate units. The comparison of EXAFS measurements and molecular dynamics simul…
Properties evolution of flax/epoxy composites under fatigue loading
2014
International audience; The tension-tension fatigue behaviour of flax fibre reinforced epoxy matrix composites have been investigated for specimens having [0]12, [90]12, [0/90]3S and [±45]3S lay-ups. The Probabilized Stress-Number of cycles (P-S-N) curves have been determined for each laminate type. The measured stress and strain data allowed to quantify the evolution of the mechanical properties, i.e. stiffness, damping and permanent strain as a function of imposed cycles. Especially, the stiffening phenomenon of flax reinforcements oriented parallel to the loading direction has been confirmed. However, due to the competition between damage development and the fibre stiffening, the increas…
De la psychomécanique du langage à la néoténie linguistique : épistémologie, transfert de concepts et emprunts terminologiques
2021
International audience; No abstract
Experimental and numerical assessment of subsurface plastic deformation induced by OFHC copper machining
2015
Strain distributions in the machined surface and subsurface of OFHC copper workpieces were determined experimentally and through numerical simulations. An experimental setup, comprising a double frame camera and a pulsed laser, was developed to measure the displacement fields using the digital image correlation (DIC) technique; strain distributions were then calculated. A numerical orthogonal cutting model was also developed and applied in order to predict such distributions. Comparison between simulated and measured results enabled an understanding of the fundamental mechanisms of plastic deformation of the machined surface of OFHC copper.; International audience; Strain distributions in t…
Integration of thermal building simulation and VR techniques for sustainable building projects
2013
Déjà présent sur HAL mais sans le fichier pdf; The importance of energy efficiency and integration of advances in building design and VR technology have led this research to focus on thermal simulation results visualized in a virtual environment to optimize building design. This paper combines the principle of integration for thermal calculation and scientific visualization in VR. The method is to use CAD models (extensively used in architectural design) to analyze a building's thermal performance and visualize it, as well as simulating it through VR technology. Interaction between users and objects in a virtual world are certainly through techniques of visualization metaphors. The object o…
La conférence du Columa 2013 racontée par des étudiants AgroSup-Dijon
2014
Document accessible depuis la notice de ProdInra : https://prodinra.inra.fr/?locale=en#!ConsultNotice:306111; La 22e conférence du Columa de l’AFPP, tenue à Dijon du 11 au 13 décembre 2013, a été suivie par des étudiants d’AgroSup-Dijon. Ils rendent compte ici de ce qu’ils en ont retenu. Ils analysent particulièrement les sessions : – « Nuisibilité » des adventices (indirecte, ex. : favoriser l’ergot, et directe). – « Cultures méditerranéennes et tropicales » (différences Dom-Tom/autres pays, techniques émergentes). – « Résistance » (extension, mécanismes, facteurs de risque). – « Transfert aux milieux » (facteurs de risque de pollution des eaux, suivis et modélisation pour les prévoir). – …
Analysis of laser shock waves and resulting surface deformations in an Al-Cu-Li aluminium alloy
2012
Abstract Laser shock processing is now a recognized surface treatment for improving fatigue or corrosion behaviour of metallic materials through the generation of a compressive stress field. In turn, the analysis of shock wave propagation is of primary importance to predict numerically morphological and mechanical surface modifications. Considering experimental and numerical analyses of shock wave propagation, and surface deformations induced by single impacts, a 2050 aluminum alloy having different microstructures was investigated under laser-shock loading. In a first step, the evolution of shock wave attenuation and elastic precursor amplitude was correctly reproduced by finite element si…
Validation d'un banc d'essais reproduisant les rafales de vent sur véhicule terrestre. Caractérisation de l'écoulement par TR-PIV
2011
National audience; Les phénomènes aérodynamiques instationnaires apparaissant autour de véhicules terrestres lors de rafales latérales, demeurent encore mal connus de par les difficultés, tant expérimentales que numériques, à reproduire fidèlement ces situations en laboratoire. L’ISAE a développé un banc d'essai, inspiré des travaux de Ryan et Dominy (Ryan et Dominy [2000]), dans lequel le déferlement de la rafale sur la maquette automobile est reproduit par un jet latéral mobile longitudinalement. L’écoulement généré par ce dispositif est validé PIV résolue en temps dans ce présent document. L’angle de dérapage obtenu lors d’une simulation de rafale présente une évolution temporelle proche…
Biomechanics of human ascending aorta and aneurysm rupture risk assessment
2021
Ascending aortic aneurysms (AsAA) and aortic dissections are life-threatening cardiovascular diseases. The main criteria for determining surgical intervention of AsAA are the maximum diameter or the increasing annual rate of the aneurysm. The mortality of the untreated aortic dissection can be 21% to 74%, depending on the delay of hospital admission.Our study aims to characterize the biomechanical properties of the ascending aorta and propose a patient-specific approach to assess the risks of rupture. The purpose of this PhD work is multifold.On the one hand, biaxial tensile tests were performed on AsAA samples obtained from one hundred patients with surgery of AsAA. The impact on the diffe…