École normale supérieure de Cachan

About: École normale supérieure de Cachan is a education organization based out in Cachan, Île-de-France, France. It is known for research contribution in the topics: Decidability & Nonlinear system. The organization has 2717 authors who have published 5585 publications receiving 175925 citations.

Development of Roughness in Crack Propagation

Abstract: We report on the statistical analysis of experimental measurements of the crack roughness for a fracture initiated from a straight notch in a granite sample. The crack surface is shown to develop a self-affine character over a correlation length ξ which depends on the distance to the notch y as a power law ξ ∝ yα characterized by a dynamic exponent 1/α estimated to be 1.2 ± 0.15. The self-affine roughness exponent below the correlation length is found to be 0.80 ± 0.05. The scaling is obtained from two maps of the surface, consisting each in more than 105 data points.

Thermal parameter identification of simplified building model with electric appliance

Abstract: In order to reduce heat energy demand in residential building, thermal insulation and indoor air tightness become more important. However, in a well-insulated environment, internal heat gain caused by solar radiation, metabolism and losses of home electric appliance (i.e. refrigerator, lamp, television, etc.) can be dominant to home global energy management. To quantify and to modelize the heat gain due to home appliances, we begin experimental measurements in a well-insulated room. The first step in this work is the identification of the room. In this paper we suggest a 1R1C lumped parameter circuit which presents a building thermal model using thermal-electric analogy. Then, we identify the circuit components (the global thermal resistor and the global thermal capacitor) from the heat balance equation and experimental results. Based on the model and the obtained parameters, we simulate the indoor temperature of the model using Matlab/Simulink. To check its accuracy we compare the measured data and simulation results and calculate their error ratio.