Veranstaltungen
Aufgrund notwendiger Maßnahmen zum Infektionsschutz ist die Teilnahme an Veranstaltungen am Institut gegenwärtig für Gäste leider nicht möglich.
Viele Veranstaltungen werden aktuell auch online durchgeführt. Informationen zum Zugang finden Sie jeweils unter „mehr” bei dem betreffenden Eintrag.
- Dienstag, 17.11.2020, 13:30 Uhr (Online Event)
- Seminar Numerische Mathematik
Prof. Peter Berg, University of Alberta, Kanada:
From microscale to macroscale properties of polymer electrolyte membranes: A case for pore network models
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Online Event
Abstrakt
We present the first attempt at describing the flow of water and protons through polymer electrolyte membranes (PEM) by use of an elastic pore network model. The main feature of our approach lies in the interplay between fluxes and pore structures, determined by randomized pore properties, the elasticity of the pores, and the liquid pressure distribution across the network.
Closed-form solutions of the Poisson-Nernst-Planck-Stokes equations along each bond (pore) are employed and coupled to a swelling model for the pores which are embedded in the elastic PEM backbone. All parameter values are taken from the literature, leaving little room for the fitting of model results to literature values.
The resulting nonlinear problem is solved computationally in an efficient manner. More importantly, computed PEM properties at different operating conditions, such as the specific conductivity and the electro-osmotic drag coefficient, compare favourably to values in the literature. In addition, the analysis reveals insights into the nonlinear couplings between transport processes and the structure of the elastic domain which motivates studies of other elastic, nanofluidic systems.
Weitere Informationen
For zoom login details please contact Alexander Linke linke@wias-berlin.de
Veranstalter
WIAS Berlin
- Mittwoch, 18.11.2020, 10:00 Uhr (Online Event)
- Forschungsseminar Mathematische Statistik
Dr. Matthias Löffler, ETH Zürich:
Computationally efficient sparse clustering
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Online Event
Weitere Informationen
Der Vortrag findet bei Zoom statt: https://zoom.us/j/159082384
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Mittwoch, 18.11.2020, 15:15 Uhr (Online Event)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Janusz Ginster, Humboldt-Universität zu Berlin:
On the motion of curved dislocations in three dimensions: Simplified linearized elasticity
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Online Event
Abstrakt
In this talk we discuss a simplified equilibrium problem for a curved dislocation line in a three-dimensional domain. As the core radius tends to zero, we derive an asymptotic expression to characterize the induced elastic energy. We then obtain the force on the dislocation line as the variation of thi sexpression and identify the highest order terms explicitly. As a main ingredient, we present an explicit asymptotic formula for the induced elastic strain which depends on the curvature of the dislocation line and thus highlights the difference to existing work on straight dislocation lines. Eventually, we present results on the corresponding dynamics. The presented methods area blueprint for the more physical setting of linearized isotropic elasticity. This is joint work with I. Fonseca and S. Wojtowytsch.
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Donnerstag, 19.11.2020, 15:00 Uhr (Online Event)
- TES-Seminar on Energy-based Mathematical Methods and Thermodynamics
Prof. Dr. Christian Wieners, Karlsruher Institut für Technologie:
A discontinuous Galerkin method for phase field approximations of dynamic fracture
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Online Event
Abstrakt
We present a new numerical method for dynamic fracture at small strains which is based on a discontinuous Galerkin approximation of a first order formulation for elastic waves and where the fracture is approximated by a phase field driven by a stress based fracture criterion. The staggered algorithm in time combines the implicit midpoint rule for the wave propagation followed by an implicit Euler step for the phase field evolution. Then, driven by a stress based fracture criterion, the material is degradated, and the waves are reflected at the diffusive interface. Then method is evaluated in detail in one dimension, and then we demonstrate in a 2D application the fracture evolution with multiple fractures initiated by reflections. This is joint work with Kerstin Weinberg, Siegen.
Weitere Informationen
Please register on this link: https://mathplus.de/topic-development-lab/tes-winter-2020-21/tes-seminar-on-energy-based-mathematical-methods-and-thermodynamics/
Veranstalter
Technische Universität Berlin
WIAS Berlin
- Donnerstag, 19.11.2020, 16:00 Uhr (Online Event)
- Forschungsseminar Mathematische Modelle der Photonik
Dr. Konstantinos Mamis, Hellenic Naval Academy, Greece:
Formulating nonlinear Fokker--Planck equations for dynamical systems under coloured noise excitation
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Online Event
Veranstalter
WIAS Berlin