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Modeling of radiative heat transfer of a real gas in 2D enclosure
No full textp.p. 967-974A two-dimensional radiation code based on the discrete ordinates method (DOM) coupled with spectral line-based weighted sum of grey gases (SLW) model for radiative heat transfer in non-grey absorbing–emitting media for use in conjunction with a computational fluid dynamics (CFD ) code was developed. The code was applied to four different kinds of participating media: two homogeneous and isothermal and two non-homogeneous and non- isothermal cases with a single participating gas (CO 2 or H 2 O). Predictive accuracy of the code is compared with the available results in the literature. Comp arisons reveal that the discrete or dinates method (DOM) coupled with SLW model provides accurate solutions for ra diative heat fluxes and source terms and can be used with confidence in conjunction with CFD code
Kinetic and equilibrium studies of cobalt adsorption on apricot stone activated carbon
No full textThe activated carbon from apricot stone with H3PO4 and its ability to remove Co2+ are reported. The FTIR spectroscopy brings insights on interactions between the functional groups of the carbon and Co2+. Adsorption studies are carried in batch mode by varying the initial Co2+ concentration and pH. A comparison of two kinetic models on the overall adsorption rate shows that the system is described by the pseudo-second-order kinetic model. The Freundlich model fits the data with a monolayer adsorption capacity of 111.11 mg/g at pH 9. The enthalpy and free energy indicate an endothermic and not spontaneous proces
Acquisition and excretion of bartonella quintana by the cat flea, ctenocephalides felis felis
No full textPreparation and characterization of activated coal from bitter almond shells (Prunus amygdalus) = Préparation et caractérisation d’un charbon actif à partir de la coquille d’amande (Prunus amygdalus) amère
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An accurate combination of on-the-fly interface trap and threshold voltage methods for NBTI degradation extraction
No full textComparative study between solar and conventional heating-economic study and environmental impact
No full textDegradation of poly(ether ulfone)/polyvinylpyrrolidone membranes by sodium hypochlorite : insight from advanced electrokinetic characterizations
No full textModélisation de l'endommagement d'un matériau composite stratifié à plusieurs
No full text119 p. : ill. ; 30 cmLa rupture des composites stratifiés est un phénomène complexe, dans lequel interviennent plusieurs mécanismes de ruine à différentes échelles. Généralement, l’évolution de l’endommagement a lieu sur une plage importante de chargement et une interaction significative est observée entre les différents mécanismes, qui mène à la rupture finale. La complexité de leur micro et méso structure rend difficile la modélisation et la simulation de leur réponse mécanique. La résolution de ces problèmes complexes nécessite d'utiliser des modèles fins de micromécanique, tout en conservant une approche apte au calcul de structures de complexité industrielle. Dans ce but ultime, un pont micro/méso est proposé entre les modèles classiques de micromécanique et le mésomodèle d'endommagement développé au LMT-Cachan depuis une quinzaine d'années. Un critère de rupture finale basé sur une approche numérique est établi pour prendre en considération l’accumulation de l’endommagement engendré par tous les plis. Cependant, des applications numériques pour conformer les résultats numériques par des observations microscopiques, sont mises en place sur des composites stratifiés croisés sous un chargement en traction et en flexion trois point
A review on protective relays’ developments and trends
No full textOne of the most complex disciplines in electrical
engineering is power system protection which
requires not only the proper understanding of the
different components of a power system and their
behaviours but also a good knowledge and analysis
of the abnormal circumstances and failures that can
occur in any element of a power system. Moreover,
the rapid changing and development in relays principles
as well as in their technologies are additional
factors that oblige those people working in the field
to expand and update continuously their knowledge.
In this paper, we shed light in the evolution of protective relays since the onset of electrical energy to currently. We try also to foresee the future prospects and trends in this area