Réconcilier le citoyen et la science. Autour du principe de précaution ?

Tourtelier Philippe. Réconcilier le citoyen et la science. Autour du principe de précaution ?. In: Raison présente, n°184, 4e trimestre 2012. Regards sur le principe de précaution. pp. 45-54

COMPARAISON DES DIFFERENTES METHODES D'EVALUATION DE FIDES

International audienceSummary The FIDES guide assesses the reliability of electronic systems with different methods depending on the level of information available. Depending on the progress of the product design, the definition will be more or less detailed. So, it is not always possible to make a complete component reliability study. This publication proposes to compare the results obtained through these different methods, detailed or simplified, defined in the FIDES guide (UTEC 80811): component method (or part stress), part count, families count and COTS board. The study is conducted on 5 boards from different military systems. This analysis will be supplemented by a concrete case of evaluation of a COTS consumer board to show the possibilities and interest of these methods. The objective of this two-step study is to verify the relevance of FIDES macroscopic methods ("part/family count") compared to the traditional method at the component level "Part stress".Résumé Le guide FIDES permet d'évaluer la fiabilité de systèmes électroniques à partir de différentes méthodes en fonction du niveau d'information disponible. En effet, suivant l'avancement du développement d'un produit, le dossier de définition sera plus ou moins détaillé et ne permet pas toujours de réaliser une étude de fiabilité complète composant par composant. Cette publication propose de comparer les résultats obtenus à travers ces différentes méthodes, détaillées ou simplifiées, définies dans le guide FIDES (UTE C 80811) : méthodes composant (« Part stress »), comptage par famille d'article (« families count »), comptage par type d'article (« part count »), carte COTS. L'étude est réalisée sur 5 cartes issues de différents systèmes militaires. Cette analyse sera complétée d'un cas concret d'évaluation d'une carte COTS grand public pour montrer les possibilités et l'intérêt de ces méthodes. L'objectif de cette étude en 2 temps est de vérifier la pertinence des méthodes macroscopiques (par comptage) de FIDES par rapport à la méthode fine traditionnelle au niveau composant

Enhanced electromechanical coupling of piezoelectric beams through an innovative design

International audienceThis work reports the finite element model simulations of an innovative design of piezoelectric cantilevers in order to maximize their global electromechanical coupling coefficient k².A strong electromechanical coupling coefficient is necessary for piezoelectric cantilever to improve their performances as vibration energy harvesters. Its value can be increased by minimizing the strain in the width direction of the beam.The purpose of the proposed design is to block the lateral deformations of the beam while allowing longitudinal deformations. This is implemented by placing several rigid bars on the piezoelectric patches in the width direction.Such a design is interesting when strong global electromechanical coupling coefficients are needed for resonant frequency tuning by electrical methods, or to increase the performance of lead-free materials that are still weakly coupled materials

Enhanced electromechanical coupling of piezoelectric beams through an innovative design

International audienceThis work reports the finite element model simulations of an innovative design of piezoelectric cantilevers in order to maximize their global electromechanical coupling coefficient k².A strong electromechanical coupling coefficient is necessary for piezoelectric cantilever to improve their performances as vibration energy harvesters. Its value can be increased by minimizing the strain in the width direction of the beam.The purpose of the proposed design is to block the lateral deformations of the beam while allowing longitudinal deformations. This is implemented by placing several rigid bars on the piezoelectric patches in the width direction.Such a design is interesting when strong global electromechanical coupling coefficients are needed for resonant frequency tuning by electrical methods, or to increase the performance of lead-free materials that are still weakly coupled materials

Inflammatory Bowel Diseases and School Absenteeism

International audienceObjectives - Inflammatory bowel diseases (IBDs) are chronic diseases which negatively affect the schooling of children. The aim is to analyze school absenteeism and its causes in children followed for IBD. Methods - A prospective multicenter study of IBD patients aged from 5 to 18 years old, from September 2016 to June 2017. Data on absenteeism and its causes were collected via a monthly questionnaire completed by patients or their family by mail. The results were compared with existing data supplied by the school authorities (497 students without IBD divided by class). Results - A total of 106 patients (62 boys), median age of 14 (5-18), were included. The global response rate was 83.1%. The patients with IBD were absent an average of 4.8% ± 5.5% of school days during the school year, against 3.2% ± 1.6% for non IBD group (P = 0.034). Digestive disorders accounted for 34% of the causes of absenteeism. Approximately 27% of the absences were due to scheduled events (hospitalizations, endoscopy, or consultations). By excluding the absences for scheduled care, the rate of school absenteeism of patients with IBD is significantly lower than that of non-IBD group. Conclusion - Children with IBD are more frequently absent from school than non-IBD group. The main cause of school absenteeism appears to be associated with the disease itself. The share of scheduled absenteeism is quite large. The organization and scheduling of the patients' care path must be a priority to maximally limit the negative impact of their disease on the patients' schooling