Search results for "Engineering sciences"
showing 10 items of 2347 documents
QUANTIFICATION OF MUSCLE FATIGUE WITHWAVELET ANALYSIS BASED ON EMG DURING MYOELECTRICAL STIMULATION
2012
6; International audience; We propose a device dedicated to real time analysis of electromyograms (EMG) under myoelectrical stimulation (ES). The muscular fatigue analysis, which is obtained by the use of a dedicated analog circuit and a processing part, is the main purpose of this study. The description of a hardware device which incorporates an electro-stimulator and an electromyogram amplifier combined to a computer is detailed. Then, we present a muscular fatigue analysis part based on wavelet decomposition in order to extract a fatigue index, which is confronted with synthetic and experimental data. We conclude that the CWT index applies well to M waves. The noise sensitivity is invest…
Design of a LLC Resonant Converter for Powering a PEM Electrolyzer
2021
International audience; This paper proposes the design of a LLC resonant converter to supply a proton exchange membrane (PEM) electrolyzer. The PEM requires a low voltage with high current, a reduced output voltage ripple, and an overdamped dynamic behavior of the converter to avoid voltage overshoots. The designed converter allows satisfying the design constraints, minimizing switching and reverse recovery losses; the efficiency is influenced mainly by the output rectifier's conduction losses.
Silencing and enhancement of second-harmonic generation in optical gap antennas
2012
International audience; Amplifying local electromagnetic fields by engineering optical interactions between individual constituents of an optical antenna is considered fundamental for efficient nonlinear wavelength conversion in nanometer-scale devices. In contrast to this general statement we show that high field enhancement does not necessarily lead to an optimized nonlinear activity. In particular, we demonstrate that second-harmonic responses generated at strongly interacting optical gap antennas can be significantly suppressed. Numerical simulations are confirming silencing of second-harmonic in these coupled systems despite the existence of local field amplification. We then propose a…
Design and Development of a Labview Application for the Measurement of the Complex Impedance of a Fuel Cell in Real Time
2014
International audience; To optimize the performance of fuel cells and to deepen the knowledge of their behavior, it is necessary to make measurements in real time. To run such a measure, it is necessary to use specific software and hardware tools to instrumentation fuel cells. In this context, we presented the steps of designing and developing an application for the measurement of the complex impedance by electrochemical impedance spectroscopy method (EIS) using LabVIEW® software. The experimental results are obtained using a Ballard Nexa® PEM fuel cell, an electronic load produced in our laboratory and application developed by the LabVIEW® software.
FITNESS, première plateforme européenne sur l’emballage et le conditionnement des aliments
2019
National audience; FITNESS (2017-2020) est un projet financé dans le cadre du programme européen Erasmus+. Le but de ce projet est de mettre en place une plateforme virtuelle proposant librement des contenus interactifs (présentations, guides, quizz, webinaires, outils de calcul) en lien avec l’emballage alimentaire et les problématiques de conditionnement des aliments. L’objectif est d’offrir un contenu permettant de comprendre les principes et les enjeux (modules de base), et d’apprendre des techniques plus avancées permettant de maîtriser les impacts ou la sécurité sanitaires des matériaux utilisés (modules avancés). La plateforme s’adresse aussi bien aux étudiants, enseignants et profes…
Les emballages biodégradables : durée de vie du produit ou durée de vie de l’emballage ? Exemple du PLA
2019
National audience; Parmi les matériaux d’emballages issus de ressources renouvelables, il est important de bien différencier ceux qui sont biosourcés mais non biodégradables (souvent analogues aux matériaux conventionnels pétrosourcés) de ceux qui sont à la fois biosourcés et biodégradables. Pour ces derniers, la question de leur stabilité au contact des produits alimentaires s’avère alors cruciale. Le cas du poly(lactide), ou PLA, est détaillé ici, en prenant en compte non seulement sa stabilité chimique, mais aussi sa stabilité physique. Se pose alors la question de la durée de vie de l’emballage en parallèle de celle de la durée de vie de l’aliment emballé.
SYSTEMES DE VISION INTELLIGENTS : ADEQUATION ARCHITECTURE ALGORITHME, CONCEPTION ET IMPLANTATION MATERIELLES
2013
Optimisation d'un électromyostimulateur intelligent pour le reconditionnement musculaire
2017
This project aims to optimize smart electromyostimulators for the muscular reeducation. The electrostimulator optimization aims to improve the electrostimulation sessions (EMS) by obtaining informations on the muscular electical stimulations and the control application in real time in order to control the muscular response. Various control methods of the muscular force are been developed and applied on an accurate model. In first, the techniques will be applied on the partial model without taking into account the muscular fatigue then in second in taking into account the presence of fatigue and its effects. Theses control methods act on the stimulation parameters in frequency and in amplitu…
Dietary xenoestrogens differentially impair 3T3-L1 preadipocyte differentiation and persistently affect leptin synthesis
2008
International audience; Recent observations have highlighted adipogenesis alterations under exposure to several xenoestrogens at critical stages, and pointed at their possible involvement in the pathogenesis of obesity. However, it remains unclear whether these effects are mediated by classical estrogen receptor (ER) binding and subsequent transcriptional modulation. The aim of this study was to determine the (anti-)adipogenic impact of apigenin, bisphenol A, genistein and 17β-estradiol at the onset of adipose cell maturation, and to correlate it to their estrogenic potential. In steroid-free conditions, 3T3-L1 preadipocytes were induced to differentiate in the presence of xenoestrogens for…
Integrating DSS in public transportation monitoring systems
2010
Abstract Decision Support Systems (DSS) ensure the computer-based support for the conscientious decision-making in solving problems that require a large amount of information processing and complex scenarios. DSS for Transportation (DSST) are intelligent systems that are used at operational and organizational management levels. Operating a DSST in a public transportation web-based monitoring system is presented in this paper.