Optimisation des empilements dans les structures composites stratifiées avec arrêts de plis

http://www.emse.fr/~leriche/JNC18_IRISARRI_Article_8.pdfCet article introduit le concept de table de drapage pour la conception optimale de structures composites stratifiées avec arrêts de plis. La table de drapage décrit la série des arrêts de plis assurant la transition entre un empilement maître épais et un empilement plus fin. Une structure stratifiée d'épaisseur variable est représentée par une table de drapage combinée à une distribution d'épaisseur sur les régions de la structure. Un algorithme évolutionnaire est spécialisé pour l'optimisation des tables de drapage. L'optimisation de la série des arrêts de plis à l'aide de l'algorithme proposé permet de satisfaire des règles de conception qui n'avaient pu être introduites dans les études publiées à ce jour. Un large ensemble de règles de conception, représentatif des exigences industrielles actuelles, est introduit. La méthode est appliquée à un cas -test de la littérature, composé de 18 panneaux, avec des résultats convaincants. En particulier, ces résultats montrent que les règles de conception peuvent être appliquées sans pénaliser significativement le comportement en raideur et la masse de la structure

Numerical model applied to the reassessment of the serviceability and safety of AAR-affected power-plant

ICAAR 2016 - 15th International Conference on Alkali-Aggregate Reaction, Sao Paulo, BRESIL, 03-/07/2016 - 07/07/2016Veytaux power-plant is a hydraulic facility affected by AAR. The concrete deformations of the structure are transmitted to sensitive equipments connected to it with major consequences on the serviceability and safety. Predicting the amplitude and rate of future displacements is an essential condition to choose the manager's strategy: adaptation of the equipment, repair or strengthening of the structure... The main difficulty lies in the heterogeneous moisture distribution which induces complex expansion gradients and the complex interactions between chemically-induced swelling and mechanical resistance of less-affected parts of the structure. Hence, the prediction of the displacement transmitted to the equipments requires a complete chemo-mechanical model of the structure. A macroscopic model is used and takes into account various coupling with moisture, temperature and stress states in the concrete. Its fitting requires several data: material samples from the structure for laboratory tests, monitoring devices for measuring displacements, moisture and temperature.... The resulting heterogeneous displacements in the concrete structure allow to re-assess the stress-state generated in the anchored equipment, especially in the 130-m long main distributor pipe

Atlas-Free Surface Reconstruction of the Cortical Grey-White Interface in Infants

BACKGROUND: The segmentation of the cortical interface between grey and white matter in magnetic resonance images (MRI) is highly challenging during the first post-natal year. First, the heterogeneous brain maturation creates important intensity fluctuations across regions. Second, the cortical ribbon is highly folded creating complex shapes. Finally, the low tissue contrast and partial volume effects hamper cortex edge detection in parts of the brain. METHODS AND FINDINGS: We present an atlas-free method for segmenting the grey-white matter interface of infant brains in T2-weighted (T2w) images. We used a broad characterization of tissue using features based not only on local contrast but also on geometric properties. Furthermore, inaccuracies in localization were reduced by the convergence of two evolving surfaces located on each side of the inner cortical surface. Our method has been applied to eleven brains of one- to four-month-old infants. Both quantitative validations against manual segmentations and sulcal landmarks demonstrated good performance for infants younger than two months old. Inaccuracies in surface reconstruction increased with age in specific brain regions where the tissue contrast decreased with maturation, such as in the central region. CONCLUSIONS: We presented a new segmentation method which achieved good to very good performance at the grey-white matter interface depending on the infant age. This method should reduce manual intervention and could be applied to pathological brains since it does not require any brain atlas

Egg and meat production performances of two varieties of the local Ardennaise poultry breed: silver black and golden black

peer reviewedThe Ardennaise breed is emblematic of the Belgian poultry diversity. We compared two varieties of the breed, the golden black and the silver black. The comparison encompassed: (i) the morphology of adult birds, (ii) the growth, carcass characteristics and meat quality of broilers 22 weeks old, (iii) the laying rate during 52 weeks and the egg quality. Significant differences were observed in the size of mature males and females: body weight, diameter and length of the tarsus, size of the comb and wattles. The two varieties did not differ concerning the carcass and meat quality traits. The golden black has a higher laying rate and a higher yolk / albumen ratio, but lays lighter eggs. It could be interesting to complete this study by molecular markers analysis to evaluate the degree of genetic diversity between the two varieties