Cooling process for inelastic Boltzmann equations for hard spheres, Part I: The Cauchy problem

We develop the Cauchy theory of the spatially homogeneous inelastic Boltzmann equation for hard spheres, for a general form of collision rate which includes in particular variable restitution coefficients depending on the kinetic energy and the relative velocity as well as the sticky particles model. We prove (local in time) non-concentration estimates in Orlicz spaces, from which we deduce weak stability and existence theorem. Strong stability together with uniqueness and instantaneous appearance of exponential moments are proved under additional smoothness assumption on the initial datum, for a restricted class of collision rates. Concerning the long-time behaviour, we give conditions for the cooling process to occur or not in finite time.Comment: 45 page

The TRIZ-CBR synergy: A knowledge based innovation process

Today innovation is recognised as the main driving force in the market. This complex process involves several intangible dimensions, such as creativity, knowledge and social interactions among others. Creativity is the starting point of the process, and knowledge is the force that transforms and materialises creativity in new products, services and processes. In this paper a synergy that aims to assists the innovation process is presented. The synergy combines several concepts and tools of the theory of inventive problem solving (TRIZ) and the case-based reasoning (CBR) process. The main objective of this synergy is to support creative engineering design and problem solving. This synergy is based on the strong link between knowledge and action. In this link, TRIZ offers several concepts and tools to facilitate concept creation and to solve problems, and the CBR process offers a framework capable of storing and reusing knowledge with the aim of accelerating the innovation process

The Role of PTEN in Tumor Angiogenesis

During the past 20 years, the phosphatase and tensin homolog PTEN has been shown to be involved in major physiological processes, and its mutation or loss is often associated with tumor formation. In addition PTEN regulates angiogenesis not only through its antagonizing effect on the PI3 kinase pathway mainly, but also through some phosphatase-independent functions. In this paper we delineate the role of this powerful tumor suppressor in tumor angiogenesis and dissect the underlying molecular mechanisms. Furthermore, it appears that, in a number of cancers, the PTEN status determines the response to chemotherapy, highlighting the need to monitor PTEN expression and to develop PTEN-targeted therapies

Equilibration Scales in Silicic to Intermediate Magmas - Implications for Experimental Studies

International audienceExperimental phase equilibrium studies are increasingly being used for the determination of intensive variables (P, T, fH2O, fO2 ) in silicic to intermediate magmas. In contrast, silicic igneous bodies are now perceived as open, periodically recharged, systems involving only limited chemical equilibration. Thus, the use of laboratory-determined crystal–liquid equilibrium data needs clarification. Here we review the field, petrological and geochemical evidence concerning states and scales of chemical equilibrium in silicic magma bodies. It is concluded that total chemical equilibrium is generally not the rule. However, a subsystem in local equilibrium (the reactive magma) can be identified. Equilibration scales in silicic magmas are rate-limited either by diffusive flux in crystals (DICL regime) or by diffusive flux in the melt (MD regime). The recognition that equilibrium in magmas is limited to a reactive subsystem requires phase equilibrium studies to be chemically scaled. Experiments, either of total or partial equilibrium type, should aim at a close reproduction of equilibrium states specific to natural systems. The laboratory reconstruction of the natural equilibrium states guarantees a precise determination of the pre-eruptive parameters and a reliable application of the experimental data to active volcanic systems

Evidence of Titan's Climate History from Evaporite Distribution

Water-ice-poor, 5-$\mu$m-bright material on Saturn's moon Titan has previously been geomorphologically identified as evaporitic. Here we present a global distribution of the occurrences of the 5-$\mu$m-bright spectral unit, identified with Cassini's Visual Infrared Mapping Spectrometer (VIMS) and examined with RADAR when possible. We explore the possibility that each of these occurrences are evaporite deposits. The 5-$\mu$m-bright material covers 1\% of Titan's surface and is not limited to the poles (the only regions with extensive, long-lived surface liquid). We find the greatest areal concentration to be in the equatorial basins Tui Regio and Hotei Regio. Our interpretations, based on the correlation between 5-$\mu$m-bright material and lakebeds, imply that there was enough liquid present at some time to create the observed 5-$\mu$m-bright material. We address the climate implications surrounding a lack of evaporitic material at the south polar basins: if the south pole basins were filled at some point in the past, then where is the evaporite

Nouvelle méthode de détermination de la distribution de la tailles des pores d’un milieu poreux par l’injection d’un fluide à seuil

La caractérisation des milieux poreux (M.P.) en termes de porosité, de surface spécifique, de distribution de tailles des pores etc. est un enjeu important pour de nombreuses filières industrielles : récupération assistée de pétrole, thermique du bâtiment, séquestration de CO2, stockage d'énergie ... Ainsi, les phénomènes de transports liés aux écouelments au sein des M.P. ont occupé et continuent à stimuler une forte activité de recherche aussi bien fondamentale qu'appliquée. Dans cette communication, nous présentons une méthode innovante qui s'appuie sur l'écoulement d'un fluide viscoplastique à seuil au travers d'un poreux permettant de scanner la distribution de taille de pores