78 research outputs found
The air microwave yield (AMY) experiment - A laboratory measurement of the microwave emission from extensive air showers
No full textThe AMY experiment aims to measure the microwave bremsstrahlung radiation (MBR) emitted by air-showers secondary electrons accelerating in collisions with neutral molecules of the atmosphere. The measurements are performed using a beam of 510 MeV electrons at the Beam Test Facility (BTF) of Frascati INFN National Laboratories. The goal of the AMY experiment is to measure in laboratory conditions the yield and the spectrum of the GHz emission in the frequency range between 1 and 20 GHz. The final purpose is to characterise the process to be used in a next generation detectors of ultra-high energy cosmic rays. A description of the experimental setup and the first results are presented. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence
Caractérisation de l'endommagement post-impact dans un composite PA6.6/6-Sergé2.2 : indentation permanente et micro-tomographie X
No full textInternational audienceThe present experimental works study the response of a polyamide 6.6/ 6 reinforced with woven glass fibers to drop weight solicitations. Several tests were carried out under numerous impact energies. A quantitative along with a qualitative study of the induced damage are the main objectives of this study. Differentnon-destructive evaluation (NDE) methods were utilized for this purpose. The damage mechanisms were each identified using X-Ray micro-computed tomography (μCT). The impacted area was first localized using C-scan imaging, and then the depth and diameter of permanent indentation left on the impactedsurface were extracted from the ultrasonic map. These measures were later validated using 3D optical profilometry. Afterwards, a link between the X-Ray tomography results and the PI measurements was established.Dans cette étude, des essais d’impacts à faible vitesse ont été réalisés sur un polyamide 6.6/6 renforcé de fibres de verre tissées.L’objectif principal est d’étudier qualitativement et quantitativement l’endommagement induit ainsi que sa détectabilité au moyen de différentes méthodologies expérimentales.Pour ce faire, plusieurs méthodes de contrôle non destructif (CND) ont été employées. L’identification des différents mécanismes d’endommagements a été effectuée par micro-tomographie à rayons X (μCT). Des mesures ultrasonores par imagerie C-scans en transmission et en réflexion ont été utilisés pour localiser la zone endommagée ainsi que pour extraire les informations relatives à l’indentation permanente observée sur la face impactée. Ces informations ont ensuite été vérifiées par une mesure de la planéité à l’aide de la profilometrie optique3D. Une corrélation entre les résultats obtenus par micro-tomographie à rayons X et la taille de l’indentation permanente a été réalisée
Caractérisation de l'endommagement post-impact dans un composite PA6.6/6-Sergé2.2 : indentation permanente et micro-tomographie X
No full textInternational audienceThe present experimental works study the response of a polyamide 6.6/ 6 reinforced with woven glass fibers to drop weight solicitations. Several tests were carried out under numerous impact energies. A quantitative along with a qualitative study of the induced damage are the main objectives of this study. Differentnon-destructive evaluation (NDE) methods were utilized for this purpose. The damage mechanisms were each identified using X-Ray micro-computed tomography (μCT). The impacted area was first localized using C-scan imaging, and then the depth and diameter of permanent indentation left on the impactedsurface were extracted from the ultrasonic map. These measures were later validated using 3D optical profilometry. Afterwards, a link between the X-Ray tomography results and the PI measurements was established.Dans cette étude, des essais d’impacts à faible vitesse ont été réalisés sur un polyamide 6.6/6 renforcé de fibres de verre tissées.L’objectif principal est d’étudier qualitativement et quantitativement l’endommagement induit ainsi que sa détectabilité au moyen de différentes méthodologies expérimentales.Pour ce faire, plusieurs méthodes de contrôle non destructif (CND) ont été employées. L’identification des différents mécanismes d’endommagements a été effectuée par micro-tomographie à rayons X (μCT). Des mesures ultrasonores par imagerie C-scans en transmission et en réflexion ont été utilisés pour localiser la zone endommagée ainsi que pour extraire les informations relatives à l’indentation permanente observée sur la face impactée. Ces informations ont ensuite été vérifiées par une mesure de la planéité à l’aide de la profilometrie optique3D. Une corrélation entre les résultats obtenus par micro-tomographie à rayons X et la taille de l’indentation permanente a été réalisée
Caractérisation de l'endommagement post-impact dans un composite PA6.6/6-Sergé2.2 : indentation permanente et micro-tomographie X
No full textInternational audienceThe present experimental works study the response of a polyamide 6.6/ 6 reinforced with woven glass fibers to drop weight solicitations. Several tests were carried out under numerous impact energies. A quantitative along with a qualitative study of the induced damage are the main objectives of this study. Differentnon-destructive evaluation (NDE) methods were utilized for this purpose. The damage mechanisms were each identified using X-Ray micro-computed tomography (μCT). The impacted area was first localized using C-scan imaging, and then the depth and diameter of permanent indentation left on the impactedsurface were extracted from the ultrasonic map. These measures were later validated using 3D optical profilometry. Afterwards, a link between the X-Ray tomography results and the PI measurements was established.Dans cette étude, des essais d’impacts à faible vitesse ont été réalisés sur un polyamide 6.6/6 renforcé de fibres de verre tissées.L’objectif principal est d’étudier qualitativement et quantitativement l’endommagement induit ainsi que sa détectabilité au moyen de différentes méthodologies expérimentales.Pour ce faire, plusieurs méthodes de contrôle non destructif (CND) ont été employées. L’identification des différents mécanismes d’endommagements a été effectuée par micro-tomographie à rayons X (μCT). Des mesures ultrasonores par imagerie C-scans en transmission et en réflexion ont été utilisés pour localiser la zone endommagée ainsi que pour extraire les informations relatives à l’indentation permanente observée sur la face impactée. Ces informations ont ensuite été vérifiées par une mesure de la planéité à l’aide de la profilometrie optique3D. Une corrélation entre les résultats obtenus par micro-tomographie à rayons X et la taille de l’indentation permanente a été réalisée
F-SSCP Screening for Two Common Mutations HIS1070GLN and GLY1267LYS in French Wilson Patients, and Report of Two Novel Mutations
No full textCompositional Approximate Markov Chain Aggregation for PEPA Models
No full textApproximate Markov chain aggregation involves the construction of a smaller Markov chain that approximates the behaviour of a given chain. We discuss two different approaches to obtain a nearly optimal partition of the state-space, based on different notions of approximate state equivalence. Both approximate aggregation methods require an explicit representation of the transition matrix, a fact that renders them inefficient for large models. The main objective of this work is to investigate the possibility of compositionally applying such an approximate aggregation technique. We make use of the Kronecker representation of PEPA models, in order to aggregate the state-space of components rather than of the entire model
Caractérisation de l’endommagement post-impact dans un composite PA6.6/6- Sergé2.2 : indentation permanente et micro-tomographie X: Post-impact damage characterization of woven glass reinforced polyamide 6.6/6 composites : permanent indentation measurements and X-Ray tomography
No full textNational audienceDans cette étude, des essais d’impacts à faible vitesse ont été réalisés sur un polyamide 6.6/6 renforcé de fibres de verre tissées. L’objectif principal est d’étudier qualitativement et quantitativement l’endommagement induit ainsi que sa détectabilité au moyen de différentes méthodologies expérimentales. Pour ce faire, plusieurs méthodes de contrôle non destructif (CND) ont été employées. L’identification des différents mécanismes d’endommagements a été effectuée par micro-tomographie à rayons X (μCT). Des mesures ultrasonores par imagerie C-scans en transmission et en réflexion ont été utilisés pour localiser la zone endommagée ainsi que pour extraire les informations relatives à l’indentation permanente observée sur la face impactée. Ces informations ont ensuite été vérifiées par une mesure de la planéité à l’aide de la profilometrie optique 3D. Une corrélation entre les résultats obtenus par micro-tomographie à rayons X et la taille de l’indentation permanente a été réalisée
Effect of reproduction on escape responses, metabolic rates and muscle mitochondrial properties in the scallop Placopecten magellanicus
No full textInternational audienceIn scallops, gametogenesis and spawning can diminish the metabolic capacities of the adductor muscle and reduce escape response performance. To evaluate potential mechanisms underlying this compromise between reproductive investment and escape response, we examined the impact of reproductive stage (pre-spawned, spawned and reproductive quiescent) of the giant scallop, Placopecten magellanicus, on behavioural (i.e., escape responses), physiological (i.e., standard metabolic rates and metabolic rates after complete fatigue) and mitochondrial capacities (i.e., oxidative rates) and composition. Escape responses changed markedly with reproductive investment, with spawned scallops making fewer claps and having shorter responses than pre-spawned or reproductive-quiescent animals. After recuperation, spawned scallops also recovered a lower proportion of their initial escape response. Scallop metabolic rate after complete fatigue (VO2max) did not vary significantly with reproductive stage whereas standard metabolic rate (VO2min) was higher in spawned scallops. Thus spawned scallops had the highest maintenance requirements (VO2min/VO2max). Maximal capacities for glutamate oxidation by muscle mitochondria did not change with reproductive stage although levels of ANT and cytochromes as well as cytochrome C oxidase (CCO) activity did. Total mitochondrial phospholipids, sterols and the proportion of phospholipid classes differed only slightly between reproductive stages. Few modifications were detected in the fatty acid (FA) composition of the phospholipid classes except in cardiolipin (CL). In this class, pre-spawned and spawned scallops had fairly high proportions of 20:5n-3 whereas this FA in reproductive-quiescent scallops was threefold lower and 22:6n-3 was significantly higher. These changes paralleled the increases in CCO activity and suggest an important role of CL on the modifications of CCO activity in scallops. However, mitochondrial properties could not explain the decreased recuperation ability from exhausting exercise in spawned scallops. Shifts in maintenance requirements (VO2min/VO2max) and aerobic scope (VO2max - VO2min) provided the best explanation for the impact of reproduction on escape response performance
GIGAS: a set of microwave sensor arrays to detect molecular Bremsstrahlung radiation from extensive air shower
No full textInternational audienceWe present the GIGAS (Gigahertz Identification of Giant Air Shower) microwave radio sensor arrays of the EASIER project (Extensive Air Shower Identification with Electron Radiometers), deployed at the site of the Pierre Auger cosmic ray observatory. The aim of these novel arrays is to probe the intensity of the molecular bremsstrahlung radiation expected from the development of the extensive air showers produced by the interaction of ultra high energy cosmic rays in the atmosphere. In the designed setup, the sensors are embedded within the surface detector array of the Pierre Auger observatory allowing us to use the particle signals at ground level to trigger the radio system. A series of seven, then 61 sensors have been deployed in the C-band, followed by a new series of 14 higher sensitivity ones in the C-band and the L-band. The design, the operation, the calibration and the sensitivity to extensive air showers of these arrays are described in this paper
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