Reconstructing initial data using observers: error analysis of the semi-discrete and fully discrete approximations

A new iterative algorithm for solving initial data inverse problems from partial observations has been recently proposed in Ramdani et al. (Automatica 46(10), 1616-1625, 2010 ). Based on the concept of observers (also called Luenberger observers), this algorithm covers a large class of abstract evolution PDE's. In this paper, we are concerned with the convergence analysis of this algorithm. More precisely, we provide a complete numerical analysis for semi-discrete (in space) and fully discrete approximations derived using finite elements in space and an implicit Euler method in time. The analysis is carried out for abstract Schrödinger and wave conservative systems with bounded observation (locally distributed)

INFLUENCE OF PROCESSING CONDITIONS ON THE MONOTONIC PROPERTIES OF 8090 ALLOY

Three processing conditions, namely quench rate after solution heat treatment, cold work prior to aging and aging conditions, were varied and their effect on the mechanical properties of 8090 extruded flat bars was evaluated. The influence of cold work and aging conditions was examined on the underaged material for the same proof strength level. A slow quench is unfavourable both for tensile properties and SL fracture toughness due to a heavy precipitation of stable phases within grain (and subgrain) boundaries. For a same proof strength level, raising the aging temperature from 170 to 210°C improves ductility. This effect mainly results from an increased resistance to shear rupture, which is related to changes in precipitation characteristics

Carbon-reinforced magnesium and aluminium composites fabricated by liquid hot pressing

Tire de ECCM-4, Stutttgart (RFA), September 25-28, 1990SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.1990 n.127 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Characterization of a new generation gamma alloy with an increased temperature capability

Communication to : Proceedings of the international symposium TURBOMAT : 137-142, Bonn (Allemagne), June 19, 2002SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.2002 n.107 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Asymptotic behaviour of some nonlocal diffusion problems

We deal with a parabolic equation having a diffusion coefficient depending on a nonlocal quantity. We investigate the convergence of the solution towards a steady state, extending previous results obtained by [M. Chipot and B. Lovat (1999). On the asympotic behaviour of some nonlocal problems. Positivity, 3, 65-81]. Using the dynamical systems point of view, we are able to treat the case of a continuum of steady states