Analysis of a moving mask approximation for martensitic transformations

In this work we introduce a moving mask approximation to describe the dynamics of austenite to martensite phase transitions at a continuum level. In this framework, we prove a new type of Hadamard jump condition, from which we deduce that the deformation gradient must be of the form $\mathsf{1} +\mathbf{a}\otimes \mathbf{n}$ a.e. in the martensite phase. This is useful to better understand the complex microstructures and the formation of curved interfaces between phases in new ultra-low hysteresis alloys such as Zn45Au30Cu25, and provides a selection mechanism for physically-relevant energy-minimising microstructures. In particular, we use the new type of Hadamard jump condition to deduce a rigidity theorem for the two well problem. The latter provides more insight on the cofactor conditions, particular conditions of supercompatibility between phases believed to influence reversibility of martensitic transformations

A statistical analysis of a Galactic all sky survey at 1.4 GHz

Radio surveys at frequencies of about 1 GHz allow to map the synchrotron emission in a frequency range where (except for very low Galactic latitudes or towards localized regions) it dominates over the other radio components. New all sky total intensity and polarization data at 1.4 GHz have been recently collected. We focus on the Galactic radio emission correlation properties described in terms of angular power spectrum (APS). We present for the first time the APS, in both total intensity and polarization modes, for some representative Galactic cuts and suitable APS power law parametrizations.Comment: Comments: 2 pages, 2 figures; in Astronomische Nachrichten, Vol.327, Issue 5/6, p.491 (2006); Proceedings of International Conference "The Origin and Evolution of Cosmic Magnetism", 29 August - 2 September 2005, CNR Area della Ricerca, Bologna, Italy, eds. R. Beck, G. Brunetti, L. Feretti, and B. Gaensle