Multi-parameter generalization of nonextensive statistical mechanics

We show that the stochastic interpretation of Tsallis' thermostatistics given recently by Beck [Phys. Rev. Lett {\bf 87}, 180601 (2001)] leads naturally to a multi-parameter generalization. The resulting class of distributions is able to fit experimental results which cannot be reproduced within the Boltzmann's or Tsallis' formalism.Comment: ReVTex 4.0, 4 eps figure

Strain localization in polyurethane foams. Experiments and theoretical model

none2Confined compression tests up to 70% of deformation have been performed on polyurethane foams. During these experiments strain localization has been observed (Pampolini et al. 2007-2). This behavior is described by a one-dimensional model, in which the foam is represented as a chain of non-linear elastic springs with a double-well strain energy density, and the localization is attributed to progressive phase change.noneG. Del Piero; G. PampoliniDEL PIERO, Gianpietro; Pampolini, Giampier