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PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:MechE Colloquium: Mechanics of wrinkled structures
DTSTART:20220308T120000
DTEND:20220308T130000
DTSTAMP:20260504T080617Z
UID:1cf7f329d7cc8cf6e7709dcceafc27967d04077fcff4f21f03729c53
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Andrej Košmrlj\, Mechanical and Aerospace Engineering\,
  Princeton University\nFace masks are recommended for in-person attendance
  in MED 0 1418.\n\nAbstract: Wrinkling instability of compressed stiff thi
 n films bound to soft substrates has been studied for many years and the f
 ormation and evolution of wrinkles is well understood. Similar wrinkling i
 nstabilities also play important role in biology during the development of
  organs\, such as brains and guts\, and during the formation of bacterial 
 biofilms grown on soft substrates. In recent years\, the wrinkling instabi
 lity has been exploited to create structures with tunable drag\, wetting\,
  adhesion\, and to create a template for wire formation. While these studi
 es successfully demonstrated the proofs of concepts\, quantitative underst
 anding is still lacking\, because very little is known about how wrinkled 
 surfaces deform in response to interactions with the environment. To addre
 ss this issue\, we investigated the linear response of wrinkled structures
  to external forces. By mapping the problem to the Landau theory of phase 
 transitions\, we demonstrated that the linear response to external forces 
 diverges near the onset of wrinkling instability with the usual mean-field
  exponent found in critical phenomena. Interactions with the environment a
 lso dictate the morphology of wrinkled patterns in growing biological syst
 ems. I will discuss the formation of wrinkling patterns in bacterial biofi
 lms grown on agar substrates\, which usually have radial stripe patterns n
 ear the outer edge and zigzag herringbone-like patterns in the core. The o
 bserved wrinkling patterns result from uneven stress distribution in the b
 iofilm as a consequence of the depletion of slowly diffusing nutrients und
 erneath the biofilm\, which are required for bacterial growth.\n\nBio: And
 rej Košmrlj is an assistant professor of Mechanical and Aerospace Enginee
 ring at Princeton University. Andrej Košmrlj received his Ph.D. in Physic
 s from the Massachusetts Institute of Technology in 2011\, and his postdoc
 toral training at Harvard University. He joined Princeton University in 20
 15\, where his group is doing theoretical and computational research on co
 mplex systems ranging from materials science to the physics of living syst
 ems. For his research achievements\, Andrej Košmrlj has received the NSF 
 Career Award and the Alfred Rheinstein Faculty Award. For his teaching eff
 orts\, Andrej Košmrlj has received the Excellence in Teaching Award from 
 the School of Engineering and Applied Science.
LOCATION:MED 0 1418 https://plan.epfl.ch/?room==MED%200%201418 https://epf
 l.zoom.us/j/67275071152
STATUS:CONFIRMED
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