BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:MEchanics GAthering -MEGA- Seminar: Talk1 - Interplay between geom
 etry and growth generates bending cracks in the African bush elephant’s 
 skin\; Talk2 - High fidelity and fast simulations of deformable red blood 
 cells using a combined finite elements immersed boundary lattice Boltzmann
  method
DTSTART:20181129T161500
DTEND:20181129T173000
DTSTAMP:20260509T191309Z
UID:513d19b9f6233bda44e710e99dea20f4a256ae06fa8ecbd97975deac
CATEGORIES:Conferences - Seminars
DESCRIPTION:Antonio Martins\, LANE\, University of Geneva and Christos
  Kotsalos\, SPC\, University of Geneva\nInterplay between geometry and gr
 owth generates bending cracks in the African bush elephant’s skin by An
 tonio Martins\, LANE\, University of Geneva\nAbstract An intricate netw
 ork of crevices adorns the skin surface of the African bush elephant\, Lo
 xodonta africana. These micrometer-wide channels enhance the effectiveness
  of thermal regulation (by water retention) and provide protection against
  parasites and intense solar radiation (by mud adherence). However\, while
  the adaptive value of these structures was well established \, their morp
 hological characterization and generative mechanism remained unknown. Usin
 g microscopy\, computed tomography and numerical simulations\, we show tha
 t the African elephant’s skin channels are cracks in the animal’s brit
 tle outermost skin layer\, the stratum corneum. Our results reveal that t
 he latter lies on top of an intricately curved lattice of millimetric skin
  elevations (papillae)\, and we propose that the continuous growth of the 
 underlying skin layers forces the stratum corneum to bend inside the tro
 ughs between papillae\, eventually causing it to crack. Therefore\, the n
 etwork of skin crevices emerges from the bending-dominated cracking of the
  animal’s stratum corneum.\n\nHigh fidelity and fast simulations of def
 ormable red blood cells using a combined finite elements immersed boundary
  lattice Boltzmann method by Christos Kotsalos\, SPC\, University of Ge
 neva\nAbstract We present a computational framework for the simulation of
  blood flows at the microscopic level using a modular approach that consis
 ts of a lattice Boltzmann solver for the blood plasma\, a finite element s
 olver for the deformable bodies and an immersed boundary method for the fl
 uid-solid interactions. The novelty of our approach comes from the fact th
 at our suggested FEM solver with its unconditional stability and versatile
  material expressivity\, is almost as fast as mass-spring systems. For a k
 nown material\, our solver has only one free parameter that demands tuning
 \, which is related to the membrane viscoelasticity. In contrast\, state-o
 f-the-art solvers for deformable bodies have more free parameters (typical
 ly 4)\, while the calibration of the models demand special assumptions on 
 mesh topology which restricts their generality. We suggest as well a corre
 ction on the energy proposed by Skalak et al. for the red blood cell membr
 ane enhancing the strain hardening behavior at higher deformations. Our vi
 scoelasticity model for the red blood cells\, while simple enough and appl
 icable to any kind of solver as a post-processing step\, can capture accur
 ately the characteristic recovery time and tank-treading frequencies. The 
 framework is validated using experimental data\, e.g.\, optical tweezers\,
  low viscosity ektacytometry\, while its scaling capability for multiple d
 eformable bodies is proved.
LOCATION:MED 2 2423 https://plan.epfl.ch/?room=MED22423
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR