Etude de l'endommagement de structures composites à matrice thermoplastique : application aux réservoirs de stockage hyperbare de l'hydrogène = Study of damages on thermoplastic composite structures: application for hydrogen storage vessels under high pressure

National audienceLe stockage de l'hydrogène est un verrou technologique et scientifique majeur à son utilisation comme vecteur énergétique, en remplacement des sources d'énergie traditionnelles. En effet, aujourd'hui encore, aucune solution « Haute pression » ne satisfait pleinement l'ensemble des spécifications techniques et économiques des industriels. Des progrès sont donc encore nécessaires pour améliorer les performances et la durabilité des réservoirs. Depuis 1998, le CEA travaille sur le développement de réservoirs de stockage haute pression de type IV (liner polymère renforcé d'une structuration composite). L'identification des paramètres matériaux et procédé influents ainsi que des sollicitations susceptibles de modifier les performances et la durabilité des réservoirs doit être prise en compte. En ce sens, les composites à matrice thermoplastique apparaissent comme de bons candidats en terme de durabilité et sécurité (Projet Français HYPE). Cet article présente les premiers résultats de travaux visant à développer les connaissances sur les mécanismes d'endommagement de structures composites à matrice thermoplastique (polyamide) liés à leur procédé de mise en forme (enroulement filamentaire) et leur utilisation pour le stockage hyperbare. Cette étude vise notamment à optimiser les étapes de conception numérique et de fabrication grâce à la connaissance des lois de comportement et de la durabilité du matériau. Dans un premier temps, on s'intéresse à des endommagements sous sollicitations statiques avant de s'intéresser à des sollicitations dynamiques comme l'impact

Morphological assessment of non-human primate models of osteoarthritis: Comparisons of HR-MRI with CT arthrography (CTA)

International audienc

Macrodimers: ultralong range Rydberg molecules

We study long range interactions between two Rydberg atoms and predict the existence of ultralong range Rydberg dimers with equilibrium distances of many thousand Bohr radii. We calculate the dispersion coefficients $C_{5}$, $C_{6}$ and $C_{8}$ for two rubidium atoms in the same excited level $np$, and find that they scale like $n^{8}$, $n^{11}$ and $n^{15}$, respectively. We show that for certain molecular symmetries, these coefficients lead to long range potential wells that can support molecular bound levels. Such macrodimers would be very sensitive to their environment, and could probe weak interactions. We suggest experiments to detect these macrodimers.Comment: 4 pages, submitted to PR

Quantitative analysis of vegetative growth in response to nitrogen stress for<em> vitis vinifera</em> L. CV. Syrah from pot experiments

International audienc

Multi-scale crest line extraction based on half Gaussian Kernels

International audienceCrest line extraction has always been a challenging task in image processing and its applications. It is possible to detect ridges and valleys in images using second order filters. In order to estimate crest lines of variable widths, a multi-scale analysis of the image is required. In this paper we propose a new ridge/valley detection method in images based on the difference of rotating Gaussian semi filters adapted in a multi-scale process. Due to the directional filters, we obtain a new ridge/valley anisotropic detector enabling very precise detection of ridge/valley of varied widths. Moreover, as the detector filters compute the two directions of crest lines, even highly bended crest lines are correctly extracted. Numerical comparisons with other oriented Gaussian filters and results on real images validate the interest of this method

Investigation of trap induced power drift on 0.15µm GaN technology after aging tests

International audienc

Direct trace and ultra-trace metals determination in crude oil and fractions by inductively coupled plasma mass spectrometry

cited By 13International audienceA method was developed to analyze direct trace and ultra-trace metal elements in crude oil and its fractions (maltenes-asphaltenes) by ICP-MS after sample dilution in xylene. Efficient introduction of organic compounds requires addition of O2 for complete combustion of the sample; carbon deposit on cones (interface) and extraction lenses was minimized by optimization of argon to oxygen ratio in the plasma. A PFA-100 (100 μ1.mn-1) MicroFlow Nebulizer and a Scott "double pass" chilled spray chamber were associated for an optimal introduction of petroleum products. The Q-ICP/MS was equipped with platinum cones to limit drifts caused by cone corrosion during an organic analysis. A standard addition method was realized for the calibration procedure in order to control the matrix effects. Method validation was completed by analyzing three certified reference materials from the National Institute for Standards and Technology (NIST). NIST 1085b, NIST 1084a, and NIST 1634c accuracies were approximately 10 %. Detection limit of ultra trace elements in xylene were at pg.g-1 level. A clean PFA filter system was developed to separate the oil fractions (maltenes and asphaltenes) by precipitation of asphaltenes (heavy fraction) in n-heptane. For optimal detection conditions, the samples were diluted in xylene according to their pre-estimated element concentration range. Total mass balance shows a recovery close to 100 % for Ni, V, Cu, Mo, Ag, Sn, Ba, and Pb. These results show that elements analyzed are highly concentrated in the asphaltenic fraction. Copyright © 2005 by ASTM International

Méthodologie d’extraction de la puissance de sortie au cours de vieillissements accélérés à partir de mesures I-V pulsées

International audienc

The SQ HDM SLIT-Tablet is safe and well tolerated in patients with House Dust Mite allergic rhinitis with or without asthma: A "real-life" French study

International audienceBackground: The SQ House Dust Mite (HDM) SubLingual ImmunoTherapy (SLIT)-Tablet (Acarizax) is the only allergen immunotherapy authorized by European regulatory authorities to treat HDM-induced allergic asthma (AA) that is not wellcontrolled by inhaled corticosteroids and associated with mild-to-severe HDM allergic rhinitis (AR). The aim of this study was to add evidence on the safety of the SQ HDM SLIT-Tablet in patients with AR, alone or with AA, under real-life conditions. Methods: This was a French "real-life", multicenter, non-comparative, longitudinal, prospective study. It included patients initiating the SQ HDM SLIT-Tablet for either persistent moderate-to-severe HDM AR or AA not well-controlled by inhaled corticosteroids and associated with mild-to-severe HDM AR. Adverse Events (AEs) were collected at the first intake and throughout the study. Logistic regression was used to compare safety according to asthma control before treatment initiation.Results: Between May 09, 2018 and May 29, 2019, 1526 patients were enrolled at 185 sites and 1483 were included in the safety population (SAF). Of them, 33.6% had suspected clinical manifestations of AA. Asthma was uncontrolled for 18.2% of the patients, partially controlled for 27.9% and well-controlled for 53.8%. Overall, 31.9% of the SAF patients experienced at least one AE. The percentage of patients with AEs was 29.9% among patients with AR alone and 35.9% among those with AA (p = 0.0193). No significant difference was observed in the rate of AE or SAE depending on asthma control at inclusion (2.2% of SAEs reported for patients with uncontrolled asthma, 1.4% for partly controlled and 1.1% for well-controlled).Conclusions: The overall results indicate a good SQ HDM SLIT-Tablet safety profile consistent with that reported in previous studies, regardless of asthma control

Using spad for the early detection of nitrogen deficiency on different vine varieties in pots or in the field

Using spad for the early detection of nitrogen deficiency on different vine varieties in pots or in the field. 19. Journées Internationales de Viticulture GiESC