Anévrysme de l’aorte ascendante associé à une insuffisance aortique massive: complication rare et grave de la maladie de Behçet

L'atteinte artérielle au cours de la maladie de Behçet survient chez 2 à 12% des patients et se traduit par des lésions oblitérantes et/ou anévrysmales prédominant sur les gros troncs. Les complications cardiaques sont plus rares (1 à 6%) touchant les trois tuniques. En revanche, les anévrysmes de l'aorte ascendante associés à une insuffisance aortique restent une complication très rare de la maladie de Behçet. Nous rapportons l'observation d'un jeune patient de 35ans suivie pour une maladie de Behçet compliquée d'un anévrysme de l'aorte ascendante associé à une régurgitation aortique massive. Le diagnostic a été posé sur les données cliniques radiologiques de l'échocardiographie et de la tomodensitométrie puis confirmé à l'examen histologique de la pièce. Le traitement était chirurgical et a consisté en un remplacement total de la racine de l'aorte à coeur ouvert selon la technique de Bentall afin d'éviter le risque de rupture ou de dissection. L'évolution à 18 mois de l'intervention était favorable. Le traitement médical associant la corticothérapie et les immunosuppresseurs est la règle en postopératoire pour éviter les récidives

Transferts de Chaleur Couplés dans une Cavité Partitionnée en Régime Stationnaire ou instationnaire (Unsteady coupled heat transfer in partially divided cavities)

International audienceBricks with large numbers of air cells have been designed as a method for improving the thermal insulation of the buildings. Increases in the thermal efficiency of these kinds of bricks require a better understanding of the heat transferred by thermal diffusion, natural convection and radiation. The results discussed herein clearly show the large influences of radiation heat transfer for the case of multipartitioned, differentially heated cavities, both for steady and unsteady regimes. The numerical solutions are also compared with analytical solutions based on networks of thermal resistances and with experimental measurements

Simulation numérique d’un écoulement transitoire de convection naturelle dans une cavité allongée

International audienceCe travail concerne la simulation numérique de la transition en double structure de la couche limite thermique dans une cavité différentiellement chauffée. La modélisation des transferts par convection naturelle dans la cavité rectangulaire est basée sur les hypothèses d’écoulements laminaires en régime transitoire. La formation et le développement de la couche limite thermique dans la cavité de rapport de forme (A=0,24), remplie d’eau (Pr=6,64) a été étudiée numériquement en tenant compte de paramètres spécifiques liés à l’expérience. La transition en double structure a été examinée en comparant des résultats numériques et expérimentaux

An example of comparison between ISO Norm calculations and full CFD simulations of thermal performances of hollow bricks

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Experimental study of thermal properties of a new ecological building material based on peanut shells and plaster

The aim of the present work was to investigate the thermal properties of a new building material consisting of a mixture of plaster and peanut shells for use as insulating materials in building. The properties are commonly measured by using the steady state asymmetric hot plate method, the asymmetrical transient hot plate method and the flash method. The experimental study that we have conducted, enabled us to determine the conductivity, the effusivity and the thermal diffusivity of our material. The influence of the size and the mass fraction of the peanut shell shards on thermophysical properties of tested material, was investigated. Our experimental data show a good efficiency and a significant decrease in the thermal conductivity of material with peanut shell shards compared to simple plaster material. The purpose is to obtain ecological composite materials with better thermal performance, which can contribute to improve the thermal comfort in constructions in Morocco. The results show that the density of the new material was not substantially influenced by the size of the peanut shell shards. However, the thermal conductivity and diffusivity decrease from 0.3 Wm−1 K−1 and 3.75 × 10−7 m2 s−1 to 0.14 Wm−1 K−1 and 2.11 × 10−7m2 s−1, respectively, according to the variation of the mass fraction of peanut from 0 to20%

Occupant presence and behavior: A major issue for building energy performance simulation and assessment

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Measurement of thermal properties of brick materials based on clay mixtures

International audienceThermal properties of building materials such as clay used in construction are measured using transient and steady state hot-plate and flash methods. The experimental methods are applied to measure the thermal properties of clay samples. The estimation of these thermal characteristics is based on a one dimensional model. A tridimensional model of the heat transfer in the system is considered to determine the validity conditions of the one dimensional model used to represent the center temperature. The use of a brick as a thermal insulating material requires prior knowledge of all its thermal properties. For that purpose, we have conducted an experimental study in order to characterize the thermal properties of brick samples, coming from the Moroccan Slaoui’s factory. The thermal diffusivity ‘‘a’’, specific heat ‘‘c’’ and thermal conductivity ‘‘λ’’ of this clay are experimentally obtained and their values are reported for design purposes. Finally, a comparative study based on different experimental methods is performed and the measurements are compared. The error estimations are found less than 3%

Occupant behaviour: a major issue for building energy performance

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