26 research outputs found
Ultra-high vacuum characterization of molybdenum-carbide graphite for HL-LHC collimators
No full textIn view of the High-Luminosity upgrade of the Large Hadron Collider (LHC) collimation system, a family of novel molybdenum-carbide graphite (MoGr) composites was developed to meet the challenging requirements of HL-LHC beam-halo collimation, in particular the electrical conductivity and thermo-mechanical performances. The Ultra-High Vacuum (UHV) behaviour of this material was extensively characterized to assess its compatibility with the accelerator’s specifications. The results presented in this paper correlate the outgassing behaviour with the microscopic features of MoGr compared to other graphite-based materials. Residual gas analysis (RGA) was exploited to optimize post-production treatments
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No full textInternational audienceCollective migration is a complex process that contributes to build precise tissue and organ architecture. Several molecules implicated in cell interactions also control collective migration, but their precise role and the finely tuned expression that orchestrates this complex developmental process are poorly understood. Here, we show that the timely and threshold expression of the Netrin receptor Frazzled triggers the initiation of glia migration in the developing Drosophila wing. Frazzled expression is induced by the transcription factor Glide/Gcm in a dose-dependent manner. Thus, the glial determinant also regulates the efficiency of collective migration. NetrinB but not NetrinA serves as a chemoattractant and Unc5 contributes as a repellant Netrin receptor for glia migration. Our model includes strict spatial localization of a ligand, a cell autonomously acting receptor and a fate determinant that act coordinately to direct glia toward their final destination
Classification of red wines analysed by middle infrared spectroscopy of dry extract according to their geographical origin
No full textMid-infrared transmission spectroscopy and classical analyses have been used to classify 165 wines of the same variety (Gamay), from three geographical origins (Gaillac, Beaujolais and Touraine). For spectroscopic analyses; the wines were dried on polyethylene membrane and infrared spectra were recorded by transmission between 800 cm-1 and 1800 cm-1. Classical analyses included pH, total acidity, total phenol, colour, sugars and major acids. The three groups of wines were classified by applying factorial discriminant analyses with cross validation. 97 p. cent of wines were correctly classified, based on the infrared data, versus 67 p. cent based on the classical analyses
Analyse par spectroscopie infrarouge d'extraits secs de vins rouges et classification en fonction de leur origine géographique
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Méthode de suivi de la taille de particules de caillé dans le lactosérum pendant le processus de fabrication fromagère
No full textN° Spécial: Des développements méthodologiques en imagerie à l’InraNational audienceNous proposons une nouvelle méthode pour estimer la proportion volumique des grains de caillé dans le lactosérum et leur répartition par taille en fonction du temps pendant la synérèse lors du brassage en cuve de fromagerie. Elle repose sur la mise au point d'un dispositif de prise d'images original associé à un traitement spécifique des images
Comparaison des performances de différents systèmes d'agitation en milieux de fermentation
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Vacuum Acceptance Tests for the UHV Room Temperature Vacuum System of the LHC during LS1
No full textDuring the CERN Large Hadron Collider (LHC) first long shut down (LS1), a large number of vacuum tests are carried out on consolidated or newly fabricated devices. In such a way, the vacuum compatibility is assessed before installation in the UHV system of the LHC. According to the equipment’s nature, the vacuum acceptance tests consist in functional checks, leak test, outgassing rate measurements, evaluation of contaminants by Residual Gas Analysis (RGA), pumping speed measurements and qualification of the H2 sticking probability of Non-Evaporable-Getter (NEG) coating. In this paper, the methods used for the tests and the acceptance criteria are described. A summary of the measured vacuum characteristics for the tested components is also given
Beam induced heating
No full textIn 2011, the rapid increase of the luminosity performance of LHC came at the expense of increased temperature and pressure readings on several near-beam LHC equipments. In some cases, this beam induced heating was suspected to cause beam dumps and even degradation of the equipment. This contribution aims at gathering the observations of beam induced heating due to beam coupling impedance, their current level of understanding and possible actions that could be implemented during the winter stop 2011-2012
