Tidligere gjesteforelesninger og seminarer - Side 15

Nordfjordeid Summer school 2022

Migration of particles and deformation and coalescence of droplets can be highly affected by the non-Newtonian properties of the carrier fluid. 
In this talk, we focus on the effects of viscoelasticity and yield stress (plasticity) on particle and droplet dynamics. Results are presented from numerical simulations of Navier-Stokes equations coupled with viscoelastic and elastoviscoplastic constitutive models. We will investigate how to yield stress and elasticity affect the final position of a particle in channel flows, and how complex fluid droplets deform, merge and jump on a superhydrophobic surface.

Hybrid format via Zoom possible on demand (contact timokoch at uio.no)

Til minne om Norges fremste astrofysiker og grunnlegger av Institutt for teoretisk astrofysikk, professor Svein Rosseland (1894 – 1985), arrangerer Institutt for teoretisk astrofysikk hvert år en Rosselandforelesning.

C*-algebra seminar talk by John Quigg (Arizona State University)

Brain source analysis is an important tool in brain research. It is used for example during operation planning for epilepsy patients. Given EEG (electroencephalography) and MEG (magnetoencephalography) measurements the goal is to reconstruct the brain activity, i.e. the electric potential in the brain. This poses an inverse problem. It was observed in experiments, that the accuracy of the inverse problem strongly depends on the quality of the forward simulation, in particular the head model. We discuss how modern numerical methods like discontinuous Galerkin (dG) methods and cut-cell techniques can increase the robustness of the forward problem and simplify the overall workflow. Hardware-oriented design of numerical methods allows for improved speed of the inverse simulation by making use of modern hardware resources. In order to compute the forward problem efficiently, we propose an algebraic multigrid solver for cut-cell dG methods. We introduce the challenges of EEG/MEG inverse modeling and discuss how different parts of the problem can be improved using modern numerical methods.

Hybrid format via Zoom possible on demand (contact timokoch at uio.no)

The talk will start at ca. 13:00 right after the talk by Andrea Bressan.

Abstract: Many constructions have been proposed to attain adaptivity within the IGA framework (HB-, T-, LR-splines among others).
The idea of all approaches is to break the tensor product structure of the space in order to allow a spatially varying resolution.
Here we present an approach for adaptivity in IGA aimed at solving PDEs with preconditioned Krylov methods. 
All the main ingredients of this work are already known, but their combination looks promising for the 
development of isogeometric solvers with a good balance of flexibility and computational efficiency.

Hybrid format via Zoom possible on demand (contact timokoch at uio.no)

Cristian Vignali, Physics and Astronomy Department, Bologna University (Italy)

C*-algebra seminar talk by Guillaume Aubrun (Université Claude Bernard Lyon 1)

C*-algebra seminar talk by Alistair Miller (Queen Mary University of London)

By Quentin Mauvisseau from the Natural History Museum, University of Oslo

Abstract: Dynamic Contact Lines are moving lines at which two fluids (eg air and water) and a solid meet. They offer longstanding paradoxes in the theory of continuum mechanics. I describe some aspects of their computation: a curtain-coating numerical experiment, a withdrawing plate, and a droplet between parallel plates.  All computations are done using Volume-Of-Fluid methods on octree grids, and comparisons with phase field and molecular dynamics approaches performed in collaboration with KTH, Stockholm.

Hybrid format via Zoom possible on demand (contact timokoch at uio.no)

Marianne Dahl, senior researcher at The Peace Research Institute Oslo (PRIO)

The Section 4 seminar for the Spring of 2022 will be held on Tuesdays from 10:15–12:00 (see the schedule)

C*-algebra seminar talk by Judy Packer (University of Colorado Boulder)

C*-algebra seminar talk by Roberto Conti (Sapienza University of Rome)

C*-algebra seminar / Gemini Center seminar talk by Paula Belzig (University of Copenhagen)

Abstract: I present the electrophoretic transport phenomenon of spherical soft particles. Electrophoresis is one of the important electrokinetic techniques, which is often used to characterize, and separation of colloids.  It is commonly used as a separation technique and often used in the separation of DNA, protein molecules, serum to identify paraproteins, etc. Electrophoretic transport phenomenon is also used to understand the electric properties of several bioparticles including virus, bacteria, humic cells and macromolecules and may be used to understand the transport of cargo vessel in treatments of various diseases, e.g., cancer, inflammation, multiple myeloma, rental pathological disorders and macroglobulinemia, etc. Thus, the proper understanding of the electrophoretic transport of soft particles is important to understand the characteristics features of various bio-colloids and macromolecules, which can be viewed as soft particles. In this talk, I will present some of the existing simplified models for electrophoretic transport of soft particles. In addition, I have further extended it for the real situation, considering the effect of pH-dependent charge densities of the inner core and peripheral soft polymeric layer, effect of hydrodynamic slip length of the hydrophobic core surface, etc. 

Hybrid format via Zoom possible on demand (contact timokoch at uio.no)

Max Grönke, Max Planck Institute for Astrophysics, Garching (Germany).