Experiments to increase the used Energy with the PEGASUS Railgun

The French-German Research Institute (ISL) has several railguns installed, the largest of these is the PEGASUS accelerator. It is a 6m long, 4x4 cm2 caliber distributed energy supply (DES) railgun. It has a 10 MJ capacitor bank as energy supply attached to it. In the past, this installation was used to accelerate projectiles with a mass of about 300 g to velocities up to 2500 m/s. In the ongoing investigation, it is attempted to accelerate heavier projectiles to velocities above 2000m/s. For this a new type of projectile including a payload section was developed. In this paper the results of the experiments with payload projectiles using a primary energy between 3.8 MJ and 4.8 MJ are discussed.Comment: 6 pages, 11 figures, Submitted to IEEE Transactions on Plasma Science, Special Issue -- Pulsed Power Science & Technology 201

Experimental study of the ageing of building stones exposed to sulfurous and nitric acid atmospheres

During the last few decades, due to remediation procedures, SO2 emissions in the atmosphere have decreased, unlike NOx. Air pollution has changed. Indeed, the aim of this research is to assess the effect of NOx and their interactions with SO2 on stones, particularly on limestones used in Champagne-Ardenne (France) during the restoration processes. Three French building limestones (Courville, Dom and Savonnières) and one reconstituted stone were exposed during 28 days to four strong acid atmospheres i.e. two H2SO3 solutions with different concentrations and two mixed atmospheres with different proportions of HNO3 and H2SO3. These tests produced an intensive acid attack on the stone, allowing the observation of short-term salt precipitation and the evolution of stone properties. Each day, one sample was removed from the acid atmosphere to measure the concentration of SO4(2-) and NO3(-) by ion-chromatography. The surface changes were assessed before and after the tests by 3D scanning and observations with electron microscopy. X-ray microtomography has been performed in the Centre for X-ray Tomography (UGCT) and the Department of Geology at Ghent University (Belgium) in order to observe the penetration of salts and the consequences in stones porosity. First observations showed that exposure to acid atmosphere, led to gypsum efflorescences. Obvious colour changes occurred in all tests. Salt crystallization entailed a change in the porous system, which was evidenced by 3D, mercury porosimetry and X-ray microtomography. Difference between weathered and fresh stone was highlighted by Ion chromatography analyses

Diffractive optics with harmonic radiation in 2d nonlinear photonic crystal waveguide

International audienceThe propagation of modulated light in a 2d nonlinear photonic waveguide is investigated in the framework of diffractive optics. It is shown that the dynamics obeys a nonlinear Schrodinger equation at leading order. We compute the first and second corrector and show that the latter may describe some dispersive radiation through the structure. We prove the validity of the approximation in the interval of existence of the leading term

Développement d'une offre de formation sur la gestion des données de la recherche en médecine et santé publique

Le présent mandat a été réalisé pour la Bibliothèque Universitaire de Médecine (BIUM) du CHUV ainsi que pour l’unité de Documentation et Données en Santé Publique (uDDSP) de l’Institut en Médecine Sociale et Préventive (IUMSP) de Lausanne. La problématique de la gestion des données de la recherche est actuellement l’un des axes de réflexion majeurs des universités, notamment de l’Université de Lausanne (UNIL). Les données de la recherche en médecine et santé publique, en ce sens, n’échappent pas à la règle et leur gestion est d’autant plus importante que leur partage et leur description sont des conditions sine qua non à la reproduction des expériences ainsi qu’à leur compréhension. Soucieuses de cette thématique, la BIUM et l’uDDSP ont décidé de proposer aux chercheurs de l’IUMSP ainsi que de la Faculté de Biologie et de Médecine (FBM) de l’UNIL deux modules de formation enseignant cette problématique aux scientifiques. Ce travail s’articulera autour de trois axes. Le premier consistera à réaliser une réflexion sur l'importance de la gestion des données de recherche notamment dans le contexte de la recherche biomédicale effectuée à la Faculté de Biologie et de Médecine ainsi qu’en santé publique effectuée à l’IUMSP. Le deuxième axe consistera en une revue et une analyse de formations existantes à la gestion des données de recherche en Suisse mais aussi à l’étranger. Ces formations pourront être généralistes ou s’intéresser précisément aux données biomédicales. Le but étant de faire ressortir des exemples pertinents dont nous pourrons nous inspirer par la suite. Le troisième axe consistera en la proposition de deux modules de formation complémentaires pour les chercheurs. Le premier se réalisera au début du processus de recherche et représentera une introduction à la thématique de la gestion des données de recherche. Cette introduction s’articulera autour du Data Management Plan, document indispensable dans la gestion des données de recherche. Le second module sera réalisé à la fin du cycle de recherche. Il s’intéressera plus précisément à la problématique du partage des données de la recherche, la mise en ligne sur des dépôts spécialisés ainsi que la création des métadonnées. Ces modules ne seront pas obligatoires pour les chercheurs et aucun prérequis n’est demandé. La durée de chaque module sera de deux heures, rendant difficile la création d’un compromis entre exhaustivité et rapidité. Au terme de ce travail, nous espérons donc pouvoir réaliser une formation complète, mariant pratique et théorie qui sera adaptée aux besoins des chercheurs et des institutions concernées

Derivation of BGK models for mixtures

International audienceThis paper is devoted to the construction of a BGK operator for gas mixtures. The construction is based as in ([12], [13]) on the introduction of relaxation coefficients and a principle of minimization of the entropy under constraints of moments. These free parameters are com pared with the free parameters introduced in the Thermodynamics of Irr eversible Processes approach of the Navier-Stokes system. At the end t he BGK model is proved to satisfy Fick and Newton law

Report No. 28: Review of Methodologies Applied for the Assessment of Employment and Social Impacts

Joint report with ECORYS Netherlands for the DG Employment, Social Affairs and Equal Opportunities of the European Commission, Bonn 2010 (217 pages)

Updated high-resolution grids of monthly climatic observations - the CRU TS3.10 Dataset

This paper describes the construction of an updated gridded climate dataset (referred to as CRU TS3.10) from monthly observations at meteorological stations across the world's land areas. Station anomalies (from 1961 to 1990 means) were interpolated into 0.5° latitude/longitude grid cells covering the global land surface (excluding Antarctica), and combined with an existing climatology to obtain absolute monthly values. The dataset includes six mostly independent climate variables (mean temperature, diurnal temperature range, precipitation, wet-day frequency, vapour pressure and cloud cover). Maximum and minimum temperatures have been arithmetically derived from these. Secondary variables (frost day frequency and potential evapotranspiration) have been estimated from the six primary variables using well-known formulae. Time series for hemispheric averages and 20 large sub-continental scale regions were calculated (for mean, maximum and minimum temperature and precipitation totals) and compared to a number of similar gridded products. The new dataset compares very favourably, with the major deviations mostly in regions and/or time periods with sparser observational data. CRU TS3.10 includes diagnostics associated with each interpolated value that indicates the number of stations used in the interpolation, allowing determination of the reliability of values in an objective way. This gridded product will be publicly available, including the input station series (http://www.cru.uea.ac.uk/ and http://badc.nerc.ac.uk/data/cru/)

Cenozoic paleoceanography 1986: An introduction

New developments in Cenozoic paleoceanography include the application of climate models and atmospheric general circulation models to questions of climate reconstruction, the refinement of conceptual models for interpretation of the carbon isotope record in terms of carbon mass balance, paleocirculation, paleoproductivity, and the regional mapping of paleoceanographic events by acoustic stratigraphy. Sea level change emerges as a master variable to which changes in the ocean environment must be traced in many cases, and tests of the onlap-offlap paradigm therefore are of crucial importance

SPOT: a New Monte Carlo Solver for Fast Alpha Particles

12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)The predictive transport code CRONOS has been augmented by an orbit following Monte Carlo code, SPOT (Simulation of Particle Orbits in a Tokamak). The SPOT code simulates the dynamics of non-thermal particles, and takes into account effects of finite orbit width and collisional transport of fast ions. Recent developments indicate that it might be difficult to avoid, at least transiently, current holes in a reactor. They occur already on existing tokamaks during advanced tokamak scenarios. For this reason the SPOT code has been used to study the alpha particle behaviour in the presence of current holes for both JET and ITER relevant parameters