A comment on 'Accurate spin axes and solar system dynamics'

In a recent paper, Edvardsson etal (2002) propose a new solution for the spin evolution of the Earth and Mars. Their results differ significantly with respect to previous studies, as they found a large contribution on the precession of the planet axis from the tidal effects of Phobos and Deimos. In fact, this probably results from the omission by the authors of the torques exerted on the satellites orbits by the planet's equatorial bulge, as otherwise the average torque exerted by the satellites on the planet is null.Comment: november 19, 200

Testing Lorentz symmetry with Lunar Laser Ranging

Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both general relativity and the standard model of particle physics called the standard-model extension (SME). We present new constraints on pure gravity SME coefficients obtained by analyzing lunar laser ranging (LLR) observations. We use a new numerical lunar ephemeris computed in the SME framework and we perform a LLR data analysis using a set of 20721 normal points covering the period of August, 1969 to December, 2013. We emphasize that linear combination of SME coefficients to which LLR data are sensitive and not the same as those fitted in previous postfit residuals analysis using LLR observations and based on theoretical grounds. We found no evidence for Lorentz violation at the level of $10^{-8}$ for $\bar{s}^{TX}$, $10^{-12}$ for $\bar{s}^{XY}$ and $\bar{s}^{XZ}$, $10^{-11}$ for $\bar{s}^{XX}-\bar{s}^{YY}$ and $\bar{s}^{XX}+\bar{s}^{YY}-2\bar{s}^{ZZ}-4.5\bar{s}^{YZ}$ and $10^{-9}$ for $\bar{s}^{TY}+0.43\bar{s}^{TZ}$. We improve previous constraints on SME coefficient by a factor up to 5 and 800 compared to postfit residuals analysis of respectively binary pulsars and LLR observations

Hydrogenation Catalysis in Biobased Ionic Liquids

This chapter is dedicated to hydrogenation procedures of (poly)-alkenes or unsaturated ketones in various biobased and not-biobased ionic liquids. The first part of this chapter defines the concept of biobased ionic liquids and their preparation. In the second part, hydrogenation processes performed in non-biobased ionic liquids are described. Finally, in the last part, the two themes are mixed and recent examples of hydrogenation procedures of alkenes, polyalkenes or unsaturated ketones in biobased ionic liquids are developed

Raman spectroscopy, a non-destructive solution to the study of glass and its alteration

This paper presents the potential of Raman spectroscopy, a non-destructive technique which can be applied in-situ, for the analyses of glass and their alteration. Recent analytical developments are summarised for different glass composition and practical examples are given. The paper describes how to extract compositional information from the glass, first based on the spectra profile to distinguish rapidly alkali silicate from alkaline-earth alkali silicate and lead alkali silicate glass, then using the spectral decomposition and correlations to extract quantitative data. For alkali silicate glasses, that are most prone to alteration, the spectral characteristics are described to interpret the alteration process (selective leaching or dissolution of the glass) from the Raman spectra of the altered glass. These developments have greatly widened the potential of the technique and supplement well its ability to measure the thickness of the altered layer and identify the crystalline deposits

A WCET-aware cache coloring technique for reducing interference in real-time systems

International audienceThe time predictability of a system is the condition to give safe and precise bounds on the worst-case execution time of real-time functionalities which are running on it. Commercial off-the-shelf(COTS) processors are increasingly used in embedded systems and contain shared cache memory. This component has a hard predictable behavior because its state depends on the execution history of the systems. To increase the predictability of COTS component we use cache coloring, a technique widely used to partition cache memory. Our main contribution is a WCET aware heuristic which partition task according to the needs of each task. Our experiments are made with CPLEX an ILP solver with random tasks set generated running on preemptive system scheduled with earliest deadline first(EDF)

Les céramiques post-palisséennes de provenance ancienne dans les collections françaises : analyse des glaçures

Les glaçures mises en œuvre par les céramistes post-palisséens sont dans l’ensemble assez homogènes. À partir de pièces dont la provenance est datée des xviie et xviiie siècles, nous en donnons les principales caractéristiques et tentons de dégager quelques différences afin de proposer des regroupements. Ce sont de faibles variations dans les compositions chimiques et la présence ou l’absence de certains éléments comme le bore qui conduisent à formuler des hypothèses sur la répartition des ateliers de production. Un bref aperçu est donné en outre sur les premiers résultats concernant un groupe de petits personnages, production post-palisséenne autrefois attribuée à Avon.The glazes used by post-Palissian potters are relatively homogeneous overall. Based on pieces dated with precision from the 17th and 18th centuries, we shall describe their principal characteristics and attempt to draw forth certain differences so as to propose groupings. The slight variations in chemical compositions, and the presence or absence of certain elements such as boron, are what have led us to formulate hypotheses on the separate production workshops. In addition, we shall give a brief overview of the first results concerning a group of small post-Palissian figures, formerly thought to have been produced in Avon

Modélisation numérique de jets et leurs applications dans la simulation des écoulements dans la cuve du modérateur du réacteur CANDU

Concepts de la turbulence -- Modèles numériques existants -- Équations en régime laminaire -- Règles sur la décomposition de Reynolds -- Équation de la continuité -- Équations de Navier -- Stokes -- Problèmes de fermeture -- Modèle des contraintes de Reynolds -- Équation de K -- Équation de E -- Modèles à deux équations -- Jets turbulents libres -- modèles analytiques -- Dynamique du jet -- Modèle de Daily et Harleman (1966) -- Modèle de Schlichting et Gersten (1960) -- Modélisation des jets turbulents -- Dimensions du domaine -- Maillage -- Conditions frontières -- Précision -- Solutionneur -- Discrétisation de la pression -- Couplage entre la pression et la vitesse -- Convergence de la solution -- Traitement au voisinage des parois -- Modèle de turbulence -- Validation de nos résultats numériques -- Influence de la hauteur de décharge -- Données expérimentales disponibles pour valider nos résultats numériques -- Jet libre -- H/D=50 -- H/D=25 -- H/D=10 -- H/D=8 -- Conclusion sur les hauteurs de décharge supérieures à 7D -- Faibles hauteurs de décharge : H/D<7 -- Développement de modèle analytique -- À l'intérieur de l'injecteur -- Région de décharge -- Zone proche de l'impact

SYRTE and PARSEC Contribution for the GBOT/GAIA Moving Target Astrometry

4 p.International audienceGAIA will measure to unprecedent precision positions, movements, and parallaxes, by the superposition of two fields apart by 174deg, taken from the L2 Earth-Sun, about 1.5 million km from the ground. To achieve the aimed precision for stars, and particularly for solar system bodies, the instantaneous position and speed of the satellite must be known respectively to 150m and 2.5 mm/s. This translates to the GBOT (Ground Base Optical Tracking) requirement to deliver quasi-daily positions of the satellite at the accuracy of 10mas relatively to the GAIA's reference frame itself (Altmann et al., 2010, this proceeding). The challenge increases because the satellite will probably be dimmer than R 17th magnitude and will be moving on average at 30mas/s, and switching hemispheres between summer and winter. We will present the strategies worked out for the satellite centroid's determination, including tracking mode, binning, super-gaussian fit, blind co-addition of images; as well as the astrometric reduction open code designed to cope with this variety of conditions. We will show applications of these resources to observations of the satellites WMAP and PLANCK, and to fast asteroids