Michael Ortiz, California Institute of Technology, Pasadena (Stati Uniti)
Multiscale problems in crystal plasticity
Monday, June 06 2005, at 17:00
Dipartimento di Matematica - Politecnico di Milano - Via Bonardi 9 - Milano - Aula Seminari III piano |
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Abstract
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The macroscopic plasticity of ductile crystals is the net result of the collective motion of large numbers of crystal lattice defects, most notably, glissile dislocations, with structures forming at multiple length scales. These include the scale of the lattice, where dislocations may be regarded as discrete topological defects: the scale of the mean distance between dislocations, where the dynamics of the dislocation ensemble is of primary interest: and the sub-grain scale, where dislocations form characteristic patterns. The development of mathematical links between the behaviors at all scales, and the characterization of the effective macroscopic behavior of ductile crystals, remains a central and long-standing problem in physical metallurgy. Tools of the calculus of variations such as relaxation and Gamma convergence prove powerful and convenient in forging those links. I plan to review a number of mathematical problems that arise in that context, and some recent results pertaining to those problems, including: the formulation of a geometrical mechanics of discrete dislocations and the passage to the continuum: the effective energetics and dynamics of dislocation ensembles: and the relaxation and optimal scaling properties of single-crystals. |
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Mauro Spera, Università di Padova
Alcuni aspetti simplettici della teoria dei nodi
Monday, May 02 2005, at 15:00
Dipartimento di Matematica e Applicazioni - Università degli Studi di Milano Bicocca - Via Cozzi, 53 - Aula 3014 | |
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Igor Chueshov, Kharkov National University (Ucraina)
Long-time behaviour of nonlinearly damped semilinear wave equation
Monday, April 18 2005, at 17:00
Dipartimento di Matematica - Università degli Studi - Via Saldini 50 - Milano - Sala di Rappresentanza | |
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Louis Nirenberg, Courant Institute, New York (Stati Uniti)
A geometric problem and the Hopf Lemma
Wednesday, April 13 2005, at 17:00
Dipartimento di Matematica - Università degli Studi - Via Saldini 50 - Milano - Sala di Rappresentanza | |
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Francesco Baldassarri, Università di Padova
Towards an algebraic proof of Deligne's regularity criterion
Monday, April 04 2005, at 17:00
Dipartimento di Matematica - Università degli Studi - Via Saldini 50 - Milano - Sala di Rappresentanza | |
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Nicola Varopoulos, Université de Paris VI (Francia)
A classification of connected Lie groups in three different but equivalent ways
Monday, March 14 2005, at 16:00
Dipartimento di Matematica e Applicazioni - Università degli Studi di Milano Bicocca - Via Cozzi, 53 - Aula 3014 | |
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