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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.

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.

International audience