Application of Hierarchical Matrix Techniques To The Homogenization of Composite Materials

In this paper, we study numerical homogenization methods based on integral equations. Our work is motivated by materials such as concrete, modeled as composites structured as randomly distributed inclusions imbedded in a matrix. We investigate two integral reformulations of the corrector problem to be solved, namely the equivalent inclusion method based on the Lippmann-Schwinger equation, and a method based on boundary integral equations. The fully populated matrices obtained by the discretization of the integral operators are successfully dealt with using the H-matrix format

Homogenization of a Multiscale Viscoelastic Model with Nonlocal Damping, Application to the Human Lungs

International audienceWe are interested in the mathematical modeling of the deformation of the human lung tissue, called the lung parenchyma, during the respiration process. The parenchyma is a foam–like elastic material containing millions of air–filled alveoli connected by a tree– shaped network of airways. In this study, the parenchyma is governed by the linearized elasticity equations and the air movement in the tree by the Poiseuille law in each airway. The geometric arrangement of the alveoli is assumed to be periodic with a small period ε > 0. We use the two–scale convergence theory to study the asymptotic behavior as ε goes to zero. The effect of the network of airways is described by a nonlocal operator and we propose a simple geometrical setting for which we show that this operator converges as ε goes to zero. We identify in the limit the equations modeling the homogenized behavior under an abstract convergence condition on this nonlocal operator. We derive some mechanical properties of the limit material by studying the homogenized equations: the limit model is nonlocal both in space and time if the parenchyma material is considered compressible, but only in space if it is incompressible. Finally, we propose a numerical method to solve the homogenized equations and we study numerically a few properties of the homogenized parenchyma model

Art, Research, Philosophy

The idea that art can be a form of research and, therefore, a contribution to knowledge, raises a number of philosophical questions such as: What is research in, through or for art? Should art draw upon research methods from other subjects, or develop its own? What kind of forms are produced or might be produced through artistic research?This is the first book to address the questions raised by visual arts research and is designed to give those working in the area new and challenging ways to reflect on how their practices engage with questions of knowledge-construction. Covering debates within aesthetics, epistemology and visual culture, this is an ideal text for art research students

La mora del deudor (la reforma del artículo 509)

Fil: Cazeaux, Pedro Néstor. Universidad Católica Argentina. Mar del Plata, Argentin

Ensemble, pour réinventer le cinéclub

Les ciné-clubs ont disparu. Pourtant, quelques irréductibles, à contre-courant, tentent de faire vivre ces moments indispensables d’échanges et l’apprentissages du cinéma à tout âge. Pour ce faire, il faut s’appuyer sur des militants et sur une collaboration entre toutes les parties impliquées dans l’action culturelle : Éducation nationale, cinéma, mairie, médiathèque. Deux expériences exemplaire

Location dynamics of general practitioners in France

Background For several years now, the socio-political context in France has widened the territorial divide between metropolitan France and peripheral France. Access to healthcare is part of this divide, which harms small and medium-sized towns as well as rural fringes. This article focuses on these geographic dynamics in access to healthcare, with a focus on self-employed general practitioners (GPs), who are essential links in the care pathway as referring physicians. Methods This paper uses data from French public statistics from 2007 to 2017 to build spatial panels and to highlight the territorial factors that explain the dynamics of the locations of GPs. Results Over the period under review, the density of GPs has decreased and territorial disparity has increased. There is no trend towards a worsening of this isolation of either the periphery or deprived cantons with regard to the density of GPs in these areas. However, we note a clear trend towards the grouping together of different types of care within cantons, leading to a tendency towards the polarization of the healthcare supply in the territories of mainland France, which implies another type of geographical difficulty. Conclusion The increase in territorial disparities in accessibility to GPs does not really seem to correspond to the classical divides in France, but rather raises the issue of intra-metropolis and intra-periphery disparities