Hydrogen Storage: State-of-the-Art and Future Perspective.

Abstract not availableJRC.F-Institute for Energy (Petten

Mechanical Behaviour of Hi-Nicalon Fibre-Reinforced Si3N4 Matrix Composites under Monotonic and Fatigue Tensile Loading

Fully dense SiC / Si3N4 were fabricated by slurry infiltration followed by hot-pressing. Two types of pyrolytic carbon coating were deposited at the fibre-matrix interface and resulted in clearly different interfacial properties thus mechanical behaviour . Composite "A" showed a higher monotonic tensile strenght (700 MPa) and a better fatigue limit (550 MPa) compared to composite "B" (620 MPa and 450 MPa respectively). Interfacial properties were assessed by modelling of hysteresis loops.JRC.(IAM)-Institute For Advanced Material

Transverse Strain Response of Hi-Nicalon Fibre Reinforced Silicon Nitride Matrix Composites.

In this paper, the Etr response of a series of Hi-Nicalon (SiC) fibre reinforced silicon nitride matrix composites is studied. At first, the processing route of the material is briefly described. Axial and transverse tensile mechanical behaviour, along with matrix crack density measurements , are then shown. Characterisation of the interface properties and evaluation of thermal residual stresses, obtained by modelling of axial hysterisis loops are finally presented. This is followed by a short description of a micromechanical model for the Etr response UD- CMCs. To conclude, experimental and theoretical transverse strain evolution are compared and discussed.JRC.(IAM)-Institute For Advanced Material

Dynamic and thermal study of a pulsatile flow in presence of a heated rotating solid

International audienceDynamic and thermal study of a pulsatile flow in presence of a heated rotating solid. This work concerns the dynamic and the thermal study between a heated rotating solid and a pulsatile flow evolving periodically in a cylindrical cavity. The reference frequency of pulsatile flow was determined by the evolution regime to his stationary state. The frequency varied from the 1/3 reference frequency to 10 once this value. The periodicity is assured by the periodical inlet conditions. The numerical study concerns the Reynolds number less than 100 and the Taylor number less than 500, in order to avoid the presence of instabilities in the flow. Two numerical methods have been used; the finite-elements method and the finite-differences combined with ADI scheme. The fluid considered is the air with constant physiques proprieties. The influence of ratio conductivity, K, between solid conductivity and fluid conductivity, has taken from K = 10(-2) to K = 10(+3). The influence of the two periodical combined motions; rotation of the solid and axial flow, on the thermal transfer mechanism is studied. The results show that the velocity components are in phase with the rate flow but the pressure and the different thermal parameters are in difference of phase. We note also the oscillatory shape of different dynamical and thermal parameters. The frequency influence appears at the greater values. The Nusselt number is proportional to the frequencies. The results are in good agreement with previous numerical and experimental studies

Hydrogen Research Activities in the Joint Research Centre of the European Commission

Abstract not availableJRC.F-Institute for Energy (Petten

L'érosion entre nature et société

International audienc

Environnement humain de l'érosion

Les techniques de mesure des isotopes dans les sols ont été développées aux USA en particulier par Ritchie & Mc Henry à partir des années 1970, puis ont été utilisées plus tard dans d'autres pays : Canada, Australie, Angleterre, Pologne. Il s'avère que le Césium-137 s'impose comme l'un des meilleurs marqueurs de la dégradation des sols : sa durée de vie est de plus de trente ans et grâce à un seul échantillonnage il nous permet d'évaluer l'érosion des sols. Actuellement des expériences utilisant cette méthode sont menées par les auteurs sur plusieurs sites au Québec et en France. Il est prouvé que l'activité du Césium-137 dépend des données morphostructurales climatiques et également des couverts végétaux. Le lien direct entre les quantités de la pluviométrie et l'activité du Cesium-137 est évident. Ces études seront développées afin de déterminer l'impact de l'agriculture sur la qualité des sols et des eaux, en pariculier à travers l'étude concernant les relations entre agrosystèmes et sylvosystèmes pour favoriser une agriculture durable et une meilleure gestion des espaces ruraux. (Résumé d'auteur