Modélisation des transferts radiatifs dans les plasmas thermiques.

On cherche à modéliser les transferts radiatifs dans un plasma inductif d'argon pur. Un modèle spectral est développé pour les raies d'argon susceptibles d'être absorbées. Les profils d'émission et d'absorption des raies d'argon seront donc examinés. Les phénomènes radiatifs pour lesquels le plasma est transparent sont traités par un Coefficient d'Emission Nette(CEN) et les autres par un modèle diffusif spectral bien adapté aux milieux optiquement épais. On examinera les contributions relatives des différents phénomènes dans différentes configurations de torches

The Concepts of Heritage and Heritage Resource Applied to Karsts: Protecting the Choranche Caves (Vercors, France)

In 2005, French Ministry of Ecology started procedure to inscribe 18 Caves of Chorance into the World Heritage list of UNESCO. The application has to answer to three objectives: the scientific interest, definition of the territory, and to propose the management model. For the first all the heritage sources has to be identified, such as flowstone formations, karst water objects and historical curiosities. This are very important and sensitive questions specially because they have been not answered before the procedure of the inscription started off

Refining of metallurgical silicon for crystalline solar cells

International audienceA plasma-retining technique is applied to upgraded metallurgical grade silicon (UMG) to produce solar grade silicon for multi-c silicon ingots at direct costs lower than 15€/kg. Using oxygen and hydrogen as reactive gases injected in the plasma, boron is removed from the material mainly in form of BOH and BO. The boron volatili- Zation time has been reduced to 50 min compared to previous processes, by increasing the temperature of the silicon bath. At the same time, the Al, Ca, C, O concentrations are strongly reduced. From a Íirst batch of puritied UMG Silicon, multi-crystalline ingots (l2kg), wafers (125X125mm2) and solar cells have been produced for an evaluation of this intermediate material. The obtained solar cells gave efticiencies of up to ll.7%. Process development towards an up-scaled pilot equipment is on the Way to further increase the puritication efticiency

Couplage Flux-Expert / Fluent : application à la modélisation 3D d'un électrolyseur à production d'hydrogène

Les électrolyseurs à production d'hydrogène de type Westinghouse sont des dispositifs électrochimiques constitués d'un empilement de compartiments cathodiques et anodiques séparés par une membrane. Ils abritent un ensemble de phénomènes physiques couplés. Pour modéliser ces installations nous avons développé un couplage entre les logiciels Fluent® (volumes finis) et Flux-Expert® (éléments finis). Le premier est utilisé pour la résolution de la partie thermo-hydraulique du problème, le second pour la partie électrocinétique avec surtensions d'activation. Leur couplage met en œuvre un processus itératif dans lequel chacun calcule des grandeurs physiques et les transmet à l'autre. Ces interpolations de grandeurs d'un maillage sur l'autre nécessitent une localisation des points de calcul sur des régions volumiques ou surfaciques 3D. Une librairie de passation de messages simple et robuste permet aux deux codes de communiquer

Dynamique moléculaire et plasticité d'un polymère amorphe sous traction

L'amélioration des performances des matériaux polymères passent notamment par une meilleure compression du lien entre dynamiques moléculaires à l'échelle microscopique et propriétés mécaniques macroscopiques. Dans ce but, la mobilité des chaînes polymères a été sondée par une mesure de spectroscopie diélectrique lors de la déformation plastique d'un polymère vitreux

Unraveling the Developmental and Genetic Mechanisms Underpinning Floral Architecture in Proteaceae

Proteaceae are a basal eudicot family with a highly conserved floral groundplan but which displays considerable variation in other aspects of floral and inflorescence morphology. Their morphological diversity and phylogenetic position make them good candidates for understanding the evolution of floral architecture, in particular the question of the homology of the undifferentiated perianth with the differentiated perianth of core eudicots, and the mechanisms underlying the repeated evolution of zygomorphy. In this paper, we combine a morphological approach to explore floral ontogenesis and a transcriptomic approach to access the genes involved in floral organ identity and development, focusing on Grevillea juniperina, a species from subfamily Grevilleoideae. We present developmental data for Grevillea juniperina and three additional species that differ in their floral symmetry using stereomicroscopy, SEM and High Resolution X-Ray Computed Tomography. We find that the adnation of stamens to tepals takes place at early developmental stages, and that the establishment of bilateral symmetry coincides with the asymmetrical growth of the single carpel. To set a framework for understanding the genetic basis of floral development in Proteaceae, we generated and annotated de novo a reference leaf/flower transcriptome from Grevillea juniperina. We found Grevillea homologs of all lineages of MADS-box genes involved in floral organ identity. Using Arabidopsis thaliana gene expression data as a reference, we found homologs of other genes involved in floral development in the transcriptome of G. juniperina. We also found at least 21 class I and class II TCP genes, a gene family involved in the regulation of growth processes, including floral symmetry. The expression patterns of a set of floral genes obtained from the transcriptome were characterized during floral development to assess their organ specificity and asymmetry of expression

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis