Nell’ambito delle attività del progetto EBRAINS-Italy, il giorno 26 marzo dalle ore 15:00 alle ore

16:00, nell’Aula Professori II Livello, la dott.ssa Annalisa Iuorio, dell’Università degli Studi di

Napoli Parthenope, terrà il seminario:

Travelling pulses of vegetation driven by autotoxicity effects

I proponenti

A. Marasco, M. Menale

Giacomo Canevari (Verona) – Seminario di Analisi

Martedì, 8 aprile⋅16:00 – 17:00

Sala Professori I livello

A free-discontinuity problem for smectic liquid crystals

Smectic liquid crystals are a phase of matter in which the constituent molecules tend to align locally parallel to one another and to arrange themselves in layers. Experimental evidence shows that the configuration of the layers in smectic films may be complex, possibly with defects – that is, localised regions of sharp change in the orientation of the layers. Defects may occur at isolated points, along lines, or surfaces. In this talk, we discuss a free-discontinuity variational problem for smectic A liquid crystals in two dimensions. We focus on a specific form of the energy functional, which penalises dislocations of the layers along the defects and is lower semicontinuous so that minimisers exist. The talk is based on joint work with John M. Ball (Heriot-Watt University, Edinburgh and Hong Kong Institute of Advanced Studies) and Bianca Stroffolini (Università Federico II, Napoli).

Roberta Marziani (Siena)

Mercoledì, 28 maggio⋅15:00 – 16:00

Sala Professori I livello

Titolo: Gamma-convergence for plane to wrinkles transition region Abstract: Motivated by physical experiments, we consider a variational problem modelling wrinkling effect of a thin annular sheet radially stretched. We start with a brief introduction on elasticity theory for thin films. We then settle a model for an annular domain radially stretched and describe an energy scaling result for low energy wrinkle patterns [Bella-Kohn 2014]. Afterwards, to better characterize the wrinkle pattern, in particular to describe the transition  between flat and wrinkled regions we set up a toy problem and perform an asymptotic analysis, via Gamma-concergence, as the sheet thickness goes to 0.  The limiting problem is scalar and convex, but constrained and posed for measures. The latter are in some sense related to Fourier coefficients of the vertical displacement of the elastic deformation.  Eventually for the limiting problem we show existence of a minimizer and equipartition of the energy for each frequency. This is based on a joint work with Peter Bella (TU Dortmund).