3-Dimensional modeling of fault-slip rockbursting

International audienceA research program has been carried out at INERIS aiming to quantify rockburst potential from mining-induced fault-slip. As a part of the research, numerical modeling of fractured rock mass has been undertaken, using the three-dimensional distinct element code 3DEC. Results presented in this paper demonstrate a very good agreement between calculated deformations of modeled faults and the experienced rockburst sequence of the Estaque-sud district of the collier

Molecular tracing of viral diseases in aquaculture

Molecular Tracing of Viral Diseases in Aquaculture = Traçage Moléculaire des Maladies Virales en Aquaculture : Colloque, Montpellier (FRA), 2015/01/27-29International audienc

Modélisation tridimensionnelle de seisme induit

National audienceA l 'Unite d' Exploitation de Provence, le charbon est exploite ä une profondeur atteignant 1000 m. La methode d'exploitation par longue taille permet de dimensionner des chantiers de 200 m de long, pour une veine de puissance d'environ 2,8 m. Le foudroyage permanent du toit en arriere taille provoque de nombreuses secousses dans les environs immediats des chantiers. Ces ruptures des bancs surplombant la veine exploitee rendent compte de la redistdbution permanente des contraintes dans le massif environnant, ainsi que de la liberation de l'energie potentielle sous une forme plus ou moins violente

Chemical Functionalization of Carbon Supported Metal Nanoparticles by Ionic Conductive Polymer via the "Grafting From" Method

International audiencefavor Platinum nanoparticles (Pt-NPs) supported on carbon powder are prepared via a water-in-oil microemulsion method and modified by a disulfide aryl initiator either by a postgrafting method or by a one pot in situ "grafting from" method. It is shown that the grafting of the disulfide derivation initiator is quantitative from 2 to 10 wt %, independently on the method. ATRP of sodium styrene sulfonate (SSNa) has then been performed from the initiator molecules grafted on the surface of the Pt-NPs supported on an electron conductive porous substrate and electrochemical measurements are performed. Although the polymerization reaction was not total (60%), derivatization of the Pt-NPs-initiator/C with different polymerization densities and polymer molecular weights are obtained. Electrodes fabricated from such nanocomposites shows enhanced performances toward the oxygen reduction reaction. Higher activity is obtained with lower polymerization density and higher polymer molecular weight. The enhancement of activity is attributed to the difference in hydrophilic character between the polymer skeleton (which could favor oxygen transport toward active sites) and the pendant sulfonic acid groups (which favor the proton transport toward the active sites)

PdPt nanocatalyst synthesis via liquid medium sputtering

International audiencePdPt nano-catalysts were synthesized via magnetron sputtering method in vacuum on vegetal glycerin as liquid substrate. The nanoparticles formation and their dispersion in the liquid phase have been studied by varying deposition parameters as the argon pressure, the magnetron power and glycerin temperature. Pt-based nano-catalysts are incorporated into electrochemical cells and their catalytic activities towards oxygen reduction reaction (ORR) are evaluated

3-Dimensional modeling of fault-slip rockbursting

International audienc

Procédé de préparation d’un matériau composite échangeur d’ions comprenant une matrice polymère et une charge consistant en des particules échangeuses d’ions

L'objectif de ce brevet consiste à réaliser une membrane de pile a combustible sans avoir recours au procédé "casting" qui nécessite un solvant. Ce procédé d’extrusion réactive permet de former une charge inorganique pendant la mise en œuvre de la matrice polymere en présence d’un agent comptabilisant à base de copolymère synthétisé par copolymérisation radicalaire du fluorure de vinylidène avec un autre comonomère fonctionnelL'application visée de ces matériaux concerne le domaine de l’énergie (matériaux pour piles à combustible PEMFC ou DMFC, AFC, les matériaux pour batterie Lithium-ion). ainsi que le domaine de l’environnement tel que les purificateurs d’ions ou de matériaux électrochromes (efficacité énergétique)

Procédé de préparation d’un matériau composite échangeur d’ions comprenant une matrice polymère et une charge consistant en des particules échangeuses d’ions

L'objectif de ce brevet consiste à réaliser une membrane de pile a combustible sans avoir recours au procédé "casting" qui nécessite un solvant. Ce procédé d’extrusion réactive permet de former une charge inorganique pendant la mise en œuvre de la matrice polymere en présence d’un agent comptabilisant à base de copolymère synthétisé par copolymérisation radicalaire du fluorure de vinylidène avec un autre comonomère fonctionnelL'application visée de ces matériaux concerne le domaine de l’énergie (matériaux pour piles à combustible PEMFC ou DMFC, AFC, les matériaux pour batterie Lithium-ion). ainsi que le domaine de l’environnement tel que les purificateurs d’ions ou de matériaux électrochromes (efficacité énergétique)

Location of microseismic swarms induced by salt solution mining

International audienceGround failures, caving processes and collapses of large natural or man-made underground cavities can produce significant socio-economic damages and represent a serious risk envisaged by the mine managements and municipalities. In order to improve our understanding of the mechanisms governing such a geohazard and to test the potential of geophysical methods to prevent them, the development and collapse of a salt solution mining cavity was monitored in the Lorraine basin in northeastern France. During the experiment, a huge microseismic data set (similar to 50 000 event files) was recorded by a local microseismic network. 80 per cent of the data comprised unusual swarming sequences with complex clusters of superimposed microseismic events which could not be processed through standard automatic detection and location routines. Here, we present two probabilistic methods which provide a powerful tool to assess the spatio-temporal characteristics of these swarming sequences in an automatic manner. Both methods take advantage of strong attenuation effects and significantly polarized P-wave energies at higher frequencies (>100 Hz). The first location approach uses simple signal amplitude estimates for different frequency bands, and an attenuation model to constrain the hypocentre locations. The second approach was designed to identify significantly polarized P-wave energies and the associated polarization angles which provide very valuable information on the hypocentre location. Both methods are applied to a microseismic data set recorded during an important step of the development of the cavity, that is, before its collapse. From our results, systematic spatio-temporal epicentre migration trends are observed in the order of seconds to minutes and several tens of meters which are partially associated with cyclic behaviours. In addition, from spatio-temporal distribution of epicentre clusters we observed similar epicentre migration in the order of hours and days. All together, we suggest that the recorded microseismicity mainly represents detachment and block breakage processes acting at the cavity's roof, indicating a zone of critical state of stress and where partial fractures cause chain reaction failures as a result of stress redistribution processes