Search results for "COUPLAGE"

Energy management of a thermally coupled fuel cell system and metal hydride tank

2019

International audience; Being produced from renewable energy, hydrogen is one of the most efficient energy carriers of the future. Using metal alloys, hydrogen can be stored and transported at a low cost, in a safe and effective manner. However, most metals react with hydrogen to form a compound called metal hydride (MH). This reaction is an exothermic process, and as a result releases heat. With sufficient heat supply, hydrogen can be released from the as-formed metal hydride. In this work, we propose an integrated power system of a proton exchange membrane fuel cell (PEMFC) together with a hydride tank designed for vehicle use. We investigate different aspects for developing metal hydride…

Modeling and numerical simulation of the propagation of pitting corrosion of iron in chlorinated medium : contribution to the evaluation of the durab…

2012

This study deals with the understanding of the mechanisms of pitting corrosion susceptible to occur on carbon steel selected for high level nuclear waste containers. Transport/reaction models have been developed in order to simulate, by finite element method, the propagation of a pit on iron in chlorinated medium. For conservative models, pit is activated by imposing a potential on metal. Thanks to different parametric studies (geometry, environment…) simulations have permitted to classify, by severity order, the factors responsible of the increase or the inhibition of the localized corrosion rate. Otherwise, experiments on occluded (called « lead-in-pencil ») electrodes confirm that confin…

Rôle des espèces sulfures dans la corrosion des aciers non alliés : hétérogénéités de la couche de produits de corrosion et couplages galvaniques

2014

The present study relates to the problem of the long-term interim storage of nuclear wastes. In France, it is envisaged that high-level radioactive wastes will be confined in a glass matrix, stored in a stainless steel canister, itself placed in a carbon steel overpack. The wastes will then be stored at a depth of ~450 m in a deep geological disposal, drilled in a very stiff (indurated) clay (argillite) formation. A temperature as high as 90°C is expected at the steel surface because of the intense radioactivity. Anodic polarization at applied current density was used to synthetize corrosion product layers likely to be formed in storage conditions. The S235 steel electrodes were covered by …

Quantum Nanoplasmonic : from dressed atom picture to superradiance

2019

Controlling quantum emitters (atoms, molecules, quantum dots, etc.), light, and its interactions is a key issue for implementing devices for information optical processing at the quantum level. For example, controlling dynamics of emitters coupled to a high-Q cavity can be achieved through cavity quantum electrodynamics (cQED). Plasmonic structures hybrid system are of growing interest in the quantum control at the nanoscale because of their capability to confine light beyond the diffraction limit. However, its application appears notoriously limited in practical situations due to the intrinsic presence of numerous and lossy modes, which complicates the description and the interpretation of…

Théorie des spectres rovibroniques des molécules octaédriques : Hamiltonien et moments de transition

2002

This thesis is devoted to the treatment of rovibronic couplings of octahedral species for which the Born-Oppenheimer approximation is broken down. By using the octahedral formalism, a full effective rovibronic model is extended from works about molecules in a non-degenerate electronic state. This effective model is dedicated to molecules with an odd or an even number of electrons and it has been successfully applied to V(CO)6 and ReF6. For both of them we have four interacting vibronic sublevels attributed to a dynamical Jahn-Teller effect and giving rise to very complicated spectra. This model is validated by the overall agreement between predicted and observed band profiles. Moreover, an …

Ligands hybrides : synthèse et chimie de coordination

2011

This manuscript deals with the synthesis of hybrids ligands and their coordination ability. The first part is dedicated to Cp-imidazole, Cp-imidazolium and Cp-phosphine ligands. Several synthetic routes have been developed to reach these mixed ligands and their coordination chemistry has been studied with titanium. In a second part, a method developed in our laboratory to synthesize phosphine-olefines was applied to obtain a phosphino-diene bearing three potential coordination sites. We have studied the coordination modes of this hybrid ligand using various transition metals and some of the formed complexes were tested in catalysis. In the third part is described the coordination chemistry …

Réseaux métalliques pour le couplage dans des guides en dioxyde de titane

2016

National audience; Nous montrons la fabrication de réseaux métalliques enterrés entre deux couches de dioxyde de titane. En utilisant un supercontinuum, nous démontrons expérimentalement une efficacité de couplage supérieure à -8 dB pour une bande passante à 3 dB supérieure à 80 nm.

Potientalities of a hydroclimatic modelling chain at the basin scale of Burgundy.

2014

Qualité aromatique de la framboise (Rubus idaeus L.) II. Interprétation de l'indice d'arôme

1982

International audience; La mesure de l'indice d'Arôme, basée sur l'intensité de la coloration bleue qui se développe dans les distillats de framboises aromatiques traités par la vanilline en solution sulfurique concentrée, est interprétée en identifiant les principaux composés participant à cette réaction colorée. Six composés : géraniol, linalol, nérol, α-terpinéol, α- et β-ionones, ont été séparés, révélés et inolés par chromatographie sur couche mince de gel de silice (CCM) et identifiés par couplage chromatographie en phase gazeuse (CPG) et spectrométrie de masse (SM). Ces composés représentent près de 80% de la valeur de l'Indice d'Arôme d'un distillat d'une variété aromatique : Mallin…

Contribution to the study of interaction between residual stress and oxygen diffusion in a deformable and reactive solid

2011

The aim of this PhD work is to highlight the interactions between the mechanical stress and the chemical composition within diffusion of matter process for a reactive solid. The chronological evolution of our work goes from a parametric numerical study to an experimental study and reveals the role of mechanical stresses on the oxygen diffusion process.Different origins of mechanical stress were first numerically analysed from the point of view of their impacts on the process of oxygen diffusion into a metal (Zr) or a ceramic (UO2) subjected to an oxidizing environment. This approach allowed us: to identify a surface treatment (shot-peening) able to generate a residual specific stress field,…