Existence and approximation for a 3D model of thermally-induced phase transformations in shape-memory alloys

This note deals with a three–dimensional model for thermal stress–induced transformations in shape–memory materials. Microstructure, like twined martensites, is described mesoscopically by a vector of internal variables containing the volume fractions of each phase. The problem is formulated mathematically within the energetic framework of rate–independent processes. An existence result is proved and we study space–time discretizations and establish convergence of these approximations. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

From Damage to Delamination in Nonlinearly Elastic Materials at Small Strains

Brittle Griffith-type delamination of compounds is deduced by means of ??-convergence from partial, isotropic damage of three-specimen-sandwich-structures by flattening the middle component to the thickness 0. The models used here allow for nonlinearly elastic materials at small strains and consider the processes to be unidirectional and rate-independent. The limit passage is performed via a double limit: first, we gain a delamination model involving the gradient of the delamination variable, which is essential to overcome the lack of a uniform coercivity arising from the passage from partial damage to delamination. Second, the delamination gradient is suppressed. Noninterpenetration- and transmission-conditions along the interface are obtained.     

Dynamics of Synthetic Membraneless Organelles in Microfluidic Droplets

Cells can form membraneless organelles by liquid–liquid phase separation. As these organelles are highly dynamic, it is crucial to understand the kinetics of these phase transitions. Here, we use droplet‐based microfluidics to mix reagents by chaotic advection and observe nucleation, growth, and coarsening in volumes comparable to cells (pL) and on timescales of seconds. We apply this platform to analyze the dynamics of synthetic organelles formed by the DEAD‐box ATPase Dhh1 and RNA, which are associated with the formation of processing bodies in yeast. We show that the timescale of phase separation decreases linearly as the volume of the compartment increases. Moreover, the synthetic organelles coarsen into one single droplet via gravity‐induced coalescence, which can be arrested by introducing a hydrogel matrix that mimics the cytoskeleton. This approach is an attractive platform to investigate the dynamics of compartmentalization in artificial cells.     

Die elektrische Leitf?higkeitdes Meerwassers

Ohne Zusammenfassung     

Eine colorimetrische Bestimmung der Salicyls?ure

Ohne Zusammenfassung     

Gasanalyse

Ohne Zusammenfassung