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International audience; A large diameter Pulsating Heat Pipe (PHP) is a device operating as a thermosyphon on ground and as a PHP under microgravity conditions. Such a prototype with a transparent (sapphire) tube section in the adiabatic region has been tested during the 67th ESA parabolic flight campaign. Infrared visualizations of the fluid in the sapphire section along with measurements of all the relevant quantities, which characterize the device state (pressures, temperatures), are acquired during the tests and exploited for the validation of CASCO code of PHP simulation. After accurate implementation of the PHP geometry and material properties, transient simulations have been carried out. A comparison with the experiment is possible only for the cases where the PHP can be initially assumed at equilibrium. The transients for tube wall temperatures, liquid plug velocities, lengths and temperatures show a good agreement with the experiments during the start-up phase in microgravity conditions reducing the gap towards the development of a fully validated PHP design tool.

- Le texte de cette conférence a été publié dans : M. Fattal, Logos et image chez Plotin, Paris, L'Harmattan, 1998.Il a également été publié en italien dans : M. Fattal, Ricerche sul logos. Da Omero a Plotino, A cura di R. Radice, Milano, Vita e Pensiero, "Temi metafisici e problemi del pensiero antico. Studi e testi, n° 99", 2005.; International audience

International audience; This study concerns the feedback of a synthetic rubber geomembrane EPDM that was installed 12 years ago for the landfill cell cover of Lann Hir. An inspection visit has been organized to assess the condition of the geomembrane and sealing details. Part of the covering soil has been removed to allow visual inspection and take samples of the geomembrane that were subjected to analysis. The publication presents the Lann Hir landfill, the specificities of installing an EPDM geomembrane landfill cover and the test results showing that twelve years after its installation, the mechanical characteristics of the EPDM geomembrane and its seams are almost unchanged.

EBEX is a NASA-funded balloon-borne experiment designed to measure the polarization of the cosmic microwave background (CMB). Observations will be made using 1432 transition edge sensor (TES) bolometric detectors read out with frequency multiplexed SQuIDs. EBEX will observe in three frequency bands centered at 150, 250, and 410 GHz, with 768, 384, and 280 detectors in each band, respectively. This broad frequency coverage is designed to provide valuable information about polarized foreground signals from dust. The polarized sky signals will be modulated with an achromatic half wave plate (AHWP) rotating on a superconducting magnetic bearing (SMB) and analyzed with a fixed wire grid polarizer. EBEX will observe a patch covering ~1% of the sky with 8' resolution, allowing for observation of the angular power spectrum from \ell = 20 to 1000. This will allow EBEX to search for both the primordial B-mode signal predicted by inflation and the anticipated lensing B-mode signal. Calculations to predict EBEX constraints on r using expected noise levels show that, for a likelihood centered around zero and with negligible foregrounds, 99% of the area falls below r = 0.035. This value increases by a factor of 1.6 after a process of foreground subtraction. This estimate does not include systematic uncertainties. An engineering flight was launched in June, 2009, from Ft. Sumner, NM, and the long duration science flight in Antarctica is planned for 2011. These proceedings describe the EBEX instrument and the North American engineering flight. 12 pages, 9 figures, Conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010)

International audience; In this article, we question the relevance of uniform random models for algorithms that use expressions as inputs. Using a general framework to describe expressions, we prove that if there is a subexpression that is absorbing for a given operator, then, after repeatedly applying the induced simplification to a uniform random expression of size n, we obtain an equivalent expression of constant expected size. This proves that uniform random expressions lack expressivity, as soon as there is an absorbing pattern. For instance, (a + b) is absorbing for the union for regular expressions on {a, b}, hence random regular expressions can be drastically reduced using the induced simplification.