Modélisation par Eléments Finis d'une Ligne à Retard à Ondes de Love

Les microcapteurs acoustiques à ondes de surface ont largement démontré leurs performances pour détecter des composés chimiques et biologiques en milieux gazeux et liquides. Plus précisément, les dispositifs à onde de Love font l’objet d’une attention particulière en raison de leurs bons résultats en milieux liquides notamment. La conception de ces dispositifs nécessite une phase de modélisation et de simulation indispensable à leur mise en œuvre opérationnelle. Cependant, à ce jour, en raison de la complexité de ces dispositifs, la plupart des modèles présentés simulent quelques caractéristiques de propagation de l’onde. La vitesse de phase est plus particulièrement calculée afin de permettre l’estimation de la sensibilité à l’effet de masse des capteurs. Nous proposons dans cette communication d’aller au-delà des modélisations classiques en présentant l’utilisation d’un logiciel à éléments finis pour un dispositif à ondes de Love. Nous présentons ainsi une modélisation globale permettant l’estimation d’un large champ de paramètres lors du fonctionnement du dispositif. Les premiers résultats seront présentés et analysés. Les perspectives et potentialités de l’utilisation de ce logiciel pour les capteurs à ondes de Love seront également abordées

Travelers With Cutaneous Leishmaniasis Cured Without Systemic Therapy

Guidelines recommend wound care and/or local therapy as first-line treatment for cutaneous leishmaniasis. An analysis of a referral treatment program in 135 travelers showed that this approach was feasible in 62% of patients, with positive outcome in 83% of evaluable patient

Simulating the midlatitude atmospheric circulation: what might we gain from high-resolution modeling of air-sea interactions?

Purpose of Review. To provide a snapshot of the current research on the oceanic forcing of the atmospheric circulation in midlatitudes and a concise update on previous review papers. Recent findings. Atmospheric models used for seasonal and longer timescales predictions are starting to resolve motions so far only studied in conjunction with weather forecasts. These phenomena have horizontal scales of ~ 10–100 km which coincide with energetic scales in the ocean circulation. Evidence has been presented that, as a result of this matching of scale, oceanic forcing of the atmosphere was enhanced in models with 10–100 km grid size, especially at upper tropospheric levels. The robustness of these results and their underlying mechanisms are however unclear. Summary. Despite indications that higher resolution atmospheric models respond more strongly to sea surface temperature anomalies, their responses are still generally weaker than those estimated empirically from observations. Coarse atmospheric models (grid size greater than 100 km) will miss important signals arising from future changes in ocean circulation unless new parameterizations are developed

An overview of using small punch testing for mechanical characterization of MCrAlY bond coats

Considerable work has been carried out on overlay bond coats in the past several decades because of its excellent oxidation resistance and good adhesion between the top coat and superalloy substrate in the thermal barrier coating systems. Previous studies mainly focus on oxidation and diffusion behavior of these coatings. However, the mechanical behavior and the dominant fracture and deformation mechanisms of the overlay bond coats at different temperatures are still under investigation. Direct comparison between individual studies has not yet been achieved due to the fragmentary data on deposition processes, microstructure and, more apparently, the difficulty in accurately measuring the mechanical properties of thin coatings. One of the miniaturized specimen testing methods, small punch testing, appears to have the potential to provide such mechanical property measurements for thin coatings. The purpose of this paper is to give an overview of using small punch testing to evaluate material properties and to summarize the available mechanical properties that include the ductile-to-brittle transition and creep of MCrAlY bond coat alloys, in an attempt to understand the mechanical behavior of MCrAlY coatings over a broad temperature range

Love Wave acoustic sensors behavior in complex liquids. Multiparameter sensing using acoustic and electrical signals

International audienceLove wave (LW) acoustic sensors are promising devices for biochemical detection in the liquid media. However, their application for in-situ biochemical detection especially in the turbid liquid medium is not yet explored. Turbid liquids are complex in nature with both mechanical and electrical characteristics. These characteristics could be reliably estimated with LW acoustic sensor response, where some of the dedicated sensors based on electrochemistry or optical principle show limitations. This paper presents experimental responses of LW acoustic sensor to turbid liquids based on Formazin solutions and its comparison to the spectrophotometer response. Analysis of sensor’s electro-acoustic response is used to better characterize the sensor performance with turbid liquids. Further, this paper demonstrates the feasibility of LW acoustic sensor as a multiparameter sensing unit by estimating the influence of electro-mechanical parameters of the turbid liquids on the overall response of the sensor

Modelisation et simulation d'un sechoir solaire diurne et nocturne

In French Guiana, like in the countries of the African continent the access to the electrical energy is often a problem. For this reason, isolated agricultural farms requires the implementation of autonomous solar drying devices, easy to install and robust. We propose in this paper to present a solar dryer prototype to answer this problematic. The device is designed to dry agricultural products along day and night while maintaining a temperature and the air flow constant. The modelling of the dryer decomposed into subsystems using the nodal approach is also presented. The simulation results obtained are compared with experimental results and commented. 

Modelling and simulation of a doubly fed induction generator in stand alone variable speed hydro turbine

International audienceIn this paper, the authors propose an approach with problems of electricity production in isolated sites in French Guiana. Indeed, the geographical context of French Guiana implies a concentration of the population on the littoral connected to the electrical national grid "EDF", whereas population living in rural areas and in majority located at the edge of the rivers, are dedicated to their own means of production by using power diesel generators or photovoltaic system