Strain inhomogeneity in copper islands probed by coherent X-ray diffraction

International audienceThe strain field of individual epitaxial sub-micrometric copper islands is studied using coherent X-ray diffraction and finite element modelling. The strain inhomogeneity in each island is so large that the characteristic features of the island shape tend to disappear in the diffraction pattern, which is dominated by strain effects. The model confirms the tensile strain imposed to the island by the thermal mismatch occurring during the preparation of the samples. An evaluation of the residual strain is obtained by qualitatively fitting the diffraction data

Color Imaging with Multimodal Three-Photon Microscopy

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The catastrophic flash-flood event of 8–9 September 2002 in the Gard region, France: a first case study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory

The Cévennes–Vivarais Mediterranean Hydrometeorological Observatory (OHM-CV) is a research initiative aimed at improving the understanding and modeling of the Mediterranean intense rain events that frequently result in devastating flash floods in southern France. A primary objective is to bring together the skills of meteorologists and hydrologists, modelers and instrumentalists, researchers and practitioners, to cope with these rather unpredictable events. In line with previously published flash-flood monographs, the present paper aims at documenting the 8–9 September 2002 catastrophic event, which resulted in 24 casualties and an economic damage evaluated at 1.2 billion euros (i.e., about 1 billion U.S. dollars) in the Gard region, France. A description of the synoptic meteorological situation is first given and shows that no particular precursor indicated the imminence of such an extreme event. Then, radar and rain gauge analyses are used to assess the magnitude of the rain event, which was particularly remarkable for its spatial extent with rain amounts greater than 200 mm in 24 h over 5500 km2. The maximum values of 600–700 mm observed locally are among the highest daily records in the region. The preliminary results of the postevent hydrological investigation show that the hydrologic response of the upstream watersheds of the Gard and Vidourle Rivers is consistent with the marked space–time structure of the rain event. It is noteworthy that peak specific discharges were very high over most of the affected areas (5–10 m3 s−1 km−2) and reached locally extraordinary values of more than 20 m3 s−1 km−2. A preliminary analysis indicates contrasting hydrological behaviors that seem to be related to geomorphological factors, notably the influence of karst in part of the region. An overview of the ongoing meteorological and hydrological research projects devoted to this case study within the OHM-CV is finally presented

Modélisation des systèmes physiques de production pour l'évaluation des coûts des activités

Notre étude s'intéresse à l'utilisation et l'exploitation des concepts de ressource et d'activité. Ces notions sont utilisées communément par les ingénieurs et les gestionnaires dans le but d'améliorer les performances des systèmes de production ou de le mesurer financièrement. Malheureusement, l'exploitation pratique de ces concepts se heurte à une difficulté commune aux deux domaines : quantifier les activités. De plus, l'absence de langage commun entre ingénieur et gestionnaire nuie à la liaison entre la vue activité des ingénieurs (vision micro) et la vue coût des gestionnaires (vision macro). Notre travail a contribué, dans un premier temps, à concevoir selon les canons de la modélisation d'entreprise, un modèle de référence qui constituait un chaînon manquant de la fonction lexicologique d'un langage commun. Les manques constatés sur l'existence de démarche concrète exploitant un modèle de référence pour évaluer un système ont abouti à notre seconde contribution : une démarche d'instanciation de notre modèle de référence en un modèle particulier. Enfin, notre objectif étant la quantification des activités, la troisième contribution porte sur une démarche de mesure du modèle particulier, intégrable aux méthodes de conception et d 'évaluation à base d'activités. Nous avons montré diverses applications possibles reposant sur la combinaison des modèles et démarches présentés.Our study concerns the use and exploitation of the resource and activity concepts used in design of a production system. These two concepts are used by engineers and managers in order to improve efficiency of production systems or to measure its financial performance. Unfortunately, the convenient exploitation of these two concepts is confronted to a common difficulty of the both fields : quantify activities. Moreover, because of the absence of common language between engineers and managers, it isn't possible to link the engineer's activity view (micro view) and the manager's cost view (macro view). These both views are however essential to quantify activities. Our work proposes a reference model based on the rules of enterprise modeling. This one constitutes the missing link for a common language and the bridge between a generic model and a particular model. Then we propose an instantiation approach to transform the reference model in a particular model. Finally, in order to quantify the activities, we propose a measure approach of the particular model, which can for example be integrated to activities based costing methods. We illustrate our approach with an industrial example.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Evaluer un système de production à l'aide d'un modèle de référence basé sur l'activity based costing

International audienceLa maîtrise de l'évaluation des coûts de production est devenue une nécessité pour les entreprises contemporaines. Depuis plusieurs décennies, la méthode ABC (Activity Based Casting) propose une solution pour répartir les coûts indirects de production à l'aide du concept d'inducteur de coût. Cependant la méthode ABC ne propose pas de critères généraux pour identifier les inducteurs de coût pertinents. Un nouveau principe de résolution basé sur l'utilisation d'un modèle de référence est proposé dans cet article dans le cas particulier des systèmes de production. Ce modèle tient compte simultanément de l'ensemble des inducteurs de coût sans pour autant complexifier l'utilisation de la méthode ABC. Une application industrielle illustre l'utilisation et l'intérêt de ce modèle

Characterizing unsaturated flow from packed scoriated lapilli : Application to Strombolian cone hydrodynamic behavior

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Turbomachinery blades damping by optimized shunted piezoelectric circuits

MarchInternational audienc

Structural multi-modal damping by optimizing shunted piezoelectric transducers

International audienceThe capacity of different auto-supplied devices using shunted piezoelectric circuits are studied here to improve structural damping by avoiding implementation of complex and heavy control devices. The presented technique uses a dedicated numerical piezo-mechanical model combining both mechanical and electrical coupling parameters. An original methodology are also introduced for optimizing the parameters of electrical shunt circuits connected to piezoelectric elements and also structural locations of these integrated transducers. The results, experimentally validated (on beams and a plate), demonstrate that vibrations can be significantly reduced when shunted piezoelectric devices are mounted on a real structure. Finally, the proposed methodology is used for optimizing shape and location of the shunted piezoelectric patches to damp several modes of a plate