BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:Order and CHAOS*: collective behavior of crowded drops in microflu
 idic systems
DTSTART:20170327T131500
DTEND:20170327T141500
DTSTAMP:20260427T203144Z
UID:97ac045fe2f79fe7eb9b45c625b60e5e0b25135d9a0868a926a6d1f3
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Sindy Tang\, Standford University\, USA\nDroplet microfl
 uidics\, in which micro-droplets serve as individual reactors\, has enable
 d a range of high-throughput biochemical processes. Although the physics o
 f single drops has been studied extensively\, the flow of crowded drops or
  concentrated emulsions—where droplet volume fraction exceeds ~80%—is 
 relatively unexplored in microfluidics. Ability to leverage concentrated e
 mulsions is critical for further increasing the throughput of droplet appl
 ications. Prior work on concentrated emulsions focused on their bulk rheol
 ogical properties. The behavior of individual drops within the emulsion is
  not well understood\, but is important as each droplet carries a differen
 t reaction.\n \nThis talk examines the collective behavior of drops in a 
 concentrated emulsion by tracking the dynamics and the fate of individual 
 drops within the emulsion. At the fast flow limit\, we show that droplet b
 reakup within the emulsion is stochastic. This contrasts the deterministic
  breakup in classical single-drop studies. We further demonstrate that the
  breakup probability is described by dimensionless numbers including the c
 apillary number and confinement factor\, and the stochasticity originates 
 from the time-varying packing configuration of the drops. To mitigate brea
 kup\, we design novel amphiphilic nanoparticles\, and show they are more e
 ffective than surfactant molecules as droplet stabilizers.\n \nAt the slo
 w flow limit\, we observe an unexpected order\, where the velocity of indi
 vidual drops in the emulsion exhibits spatiotemporal periodicity. Such per
 iodicity is surprising from both fluid and solid mechanics point of view. 
 We show the phenomenon can be explained by treating the emulsion as a soft
  crystal undergoing plasticity\, in a nanoscale system comprising thousand
 s of atoms as modeled by droplets. Our results represent a new type of col
 lective order not described before\, and have practical use in on-chip dro
 plet manipulation. From the solid mechanics perspective\, the phenomenon d
 irectly contrasts the stochasticity of dislocations in microscopic crystal
 s\, and suggests a new approach to control the mechanical forming of nanoc
 rystals.\n \n*Chaos stands for Crowded droplet breakup HydrodynAmics not 
 Ordered but Stochastic\nBio:\nDr. Sindy KY Tang joined the faculty of Stan
 ford University in September 2011 as an assistant professor in the Departm
 ent of Mechanical Engineering. She received her Ph.D. from Harvard Univers
 ity in Engineering Sciences under the supervision of Prof. George Whitesid
 es. Her lab at Stanford works on the fundamental understanding of fluid me
 chanics and mass transport in microfluidic systems\, and the application o
 f this knowledge towards problems in biology\, rapid diagnostics for healt
 h and environmental sustainability. The current areas of focus include the
  hydrodynamics of concentrated emulsions in confinements\, interfacial mas
 s transport and self-assembly\, and ultrahigh throughput opto-microfluidic
  systems for biochemical sensing and diagnostics\, water and energy sustai
 nability\, and single-cell wound healing studies. Dr. Tang’s work has be
 en recognized by multiple awards including the NSF CAREER Award\, 3M Nonte
 nured Faculty Award\, and the ACS Petroleum Fund New Investigator Award.\n
 Website: http://web.stanford.edu/group/tanglab/\n 
LOCATION:MXF 1 https://plan.epfl.ch/?room==MXF%201
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR