Characterization of a dc plasma torch by pressure measurements : analytical models and experiments

International audienceThe aim of this contribution is to propose an analytical model to describe dc plasma torch properpties at the nozzle exit from experimental data. This simplified approach attempts to highlight the influence of experimental parameters on plasma jet velocity and pressure contributions. The plasma inside the anode-nozzle is considered as stationary and is divided into the arc column and a surrounding cold layer which electrically insulates the plasma from the nozzle wall. Heat conduction is evaluated by using Kirchoff's potential, which is described, as it is done also for the electrical conductivity, as a function of the gas specific enthalpy instead of temperature

Grooming

chapter VI.27International audienceState-of-the-art on traffic grooming with a design theory approac

Paramètres influençant la structure et la fonction du globule rouge chez le cheval

The erythrocyte, as an oxygen carrier, is submitted to areas where oxidative stress is important. The maintenance of the structure and fluidity of its membrane is essential to its function. Indeed, oxygen must diffuse through the membrane and the deformability of the cell is essential to its progression through capillaries. The structure and, as a consequence, the fluidity of the membrane influence these properties. The red blood cell presents antioxydant capacities, but in some cases, free radical production is increased and exceeds antiradical defences leading to irreversible defects of the membrane, and, as a consequence, of its function. Horse erythrocyte seems to be more sensitive to oxidative stress than other species and resulting hemorheological changes could have tissular and organic consequences.Le globule rouge, de par sa fonction de transport de l’oxygène, est soumis à des milieux où le stress oxydant est important. Le maintien de la structure et de la dynamique de sa membrane est essentiel à la réalisation de sa fonction. En effet, l’oxygène doit pouvoir diffuser à travers la membrane et la cellule doit être capable de se déformer pour progresser dans les capillaires. La structure et, en conséquence, la fluidité de la membrane influencent ces propriétés. Le globule rouge présente des défenses antioxydantes importantes, mais dans certaines situations la production de radicaux libres est accrue et dépasse ces défenses aboutissant à des lésions irréversibles de la membrane cellulaire et donc de la fonction. L’érythrocyte équin semble plus sensible au stress oxydant que celui des autres espèces et les modifications hemorhéologiques qui en résultent peuvent avoir des conséquences au niveau tissulaire et organique.Peer reviewe

Reconfiguration dans les réseaux optiques

International audienceL'évolution permanente du trafic, les opérations de maintenance et l'existence de pannes dans les réseaux WDM, obligent à rerouter régulièrement des connexions. Les nouvelles demandes de connexions sont routées en utilisant les ressources disponibles et, si possible, sans modifier le routage des connexions existantes. Ceci peut engendrer une mauvaise utilisation des ressources disponibles. Il est donc préférable de reconfigurer régulièrement l'ensemble des routes des différentes connexions. Un objectif particulièrement important est alors de minimiser le nombre de requêtes simultanément interrompues lors de la reconfiguration. Nous proposons une heuristique pour résoudre ce problème dans les réseaux WDM. Les simulations montrent que cette heuristique réalise de meilleures performances que celle proposée par Jose et Somani (2003). Nous proposons également un modèle permettant de prendre en compte différentes classes de clients, avec notamment la contrainte que des requêtes, dites prioritaires, ne peuvent pas être interrompues. Une simple transformation permet de réduire le problème avec requêtes prioritaires au problème initial. De ce fait, notre heuristique s'applique également au cas autorisant des requêtes prioritaires

Randomly organized and self-assembled Na0.5Bi0.5TiO3 nanodots elaborated by sol-gel and pulsed laser deposition routes

International audienceThis work reports for the first time on the elaboration, by both chemical (sol-gel) and physical (pulsed laser deposition) routes, of lead-free ferroelectric Na0.5Bi0.5TiO3 nanodots deposited on bare c-sapphire single crystal substrates presenting a 5° miscut angle along the [110] direction. Prior to any deposition, the sapphire substrates were treated at 1350 °C, during 24 h in air, in order to increase the height of the surface steps, reaching by this way ~8 nm. The experimental parameters adjusted for the growth of Na0.5Bi0.5TiO3 dots were the concentration of sols and the number of laser pulses (50 and 100) for the sol-gel and pulsed laser deposition routes, respectively. Whereas the sol-gel route leads to randomly organized Na0.5Bi0.5TiO3 nanodots in respect to the surface steps, the pulsed laser deposition route provokes the self-assembly for some important proportion of these dots along the same surface steps. Despite the lack of organization for the sol-gel dots, the latter present a much more regular distribution in size (~100 and ~10-20 nm as an average lateral dimensions and height, respectively) compared to dots deposited by laser ablation, where three different populations of grains can be observed. In each case, the dots do not seem to be epitaxially grown

Characterization of graphs and digraphs with small process number

International audienceWe introduce the process number of a digraph as a tool to study rerouting issues in \wdm networks. This parameter is closely related to the vertex separation (or pathwidth). We consider the recognition and the characterization of (di)graphs with small process number. In particular, we give a linear time algorithm to recognize (and process) graphs with process number at most 2, along with a characterization in terms of forbidden minors, and a structural description. As for digraphs with process number 2, we exhibit a characterization that allows one to recognize (and process) them in polynomial time

Traffic Grooming in Unidirectional WDM Ring Networks using Design Theory

International audienceWe address the problem of traffic grooming in WDM rings with all-to-all uniform unitary traffic. We want to minimize the total number of SONET add-drop multiplexers (ADMs) required. We show that this problem corresponds to a partition of the edges of the complete graph into subgraphs, where each subgraph has at most C edges (where C is the grooming ratio) and where the total number of vertices has to be minimized. Using tools of graph and design theory, we optimally solve the problem for practical values and infinite congruence classes of values for a given C , and thus improve and unify all the preceding results. We disprove a conjecture of [7] saying that the minimum number of ADMs cannot be achieved with the minimum number of wavelengths, and also another conjecture of [17]

Detailed foraging behavior of Adelie penguins from Adelie Land, East Antarctica, revealed by video and accelerometry loggers

第6回極域科学シンポジウム[OB] 極域生物圏11月16日（月）　国立極地研究所１階交流アトリウ