Fall 2007
Sept 20
-------
Speaker: Daniel Blair, Georgetown University
Title: Colloids in action: Microscopic insights into
clogging and jamming
Abstract:
Suspensions of colloidal particles are astounding model systems used to
study a variety of fundamentally important problems in soft matter
physics. The versatility of colloids is due in large part to the
increasing sophistication of their synthesis, and the relative physical
simplicity of their interactions. This talk will discuss recent
experimental results on two soft-matter topics that utilize colloidal
particles; clogging during flow and jamming in glasses.
I will first present results from microfluidic studies of clogging in
model porous media. By using simple imaging techniques, and a minimal
geometric model, I will describe the physical origins of clogging in
microfluidic devices. These results demonstrate that the aggregation of
micron sized particles, in a low Reynolds number flow, is dominated by
single particle interactions. In the second half of the talk, I will
discuss the microscopic response of colloidal glasses to a
macroscopically applied compressive stress. Using time resolved laser
scanning confocal microscopy, I identify and track the motion of
thousands of colloidal particles in real space over very long times.
With this technique, and ideas garnered from metallic glasses, the
complete local strain tensor for each particle is determined. I will
demonstrate that highly localized, correlated shear and compression
transformations are necessary for colloidal glasses to approach a
maximally jammed state.
Sept 27
-------
Speaker: Samuel Zambrano,
Title: Safe sets for horseshoe maps
Speaker 2: TBA
Oct 4
-----
Speaker: Shmuel Fishman, Technion
Title: Anderson Localization for the Nonlinear Schroedinger
Equation (NLS): results and puzzles.
Abstract: The NLS is relevant for the explorations of Bose-Einstein
Condensates and for Nonlinear Classical Optics. A natural question is
whether Anderson Localization survives the effect of nonlinearities.
Relevant experimental, numerical, heuristic and rigorous results will be
reviewed. Some our preliminary results (in collaboration with A Soffer
and Y. Krivolapov), obtained in the framework of perturbation theory
will be presented.
Oct 11 (n)
------
Oct 18
------
Speaker: Visiting Graduate Student
Speaker 2: TBA
Oct 25 (n)
------
Nov 1
-----
Nov 8
-----
BURGERS symposium - no seminar
Nov 15
------
Pre DFD seminars
Nov 22
------
Thanksgiving - no seminar
Nov 29
------
Speaker: Gregg Lois, Yale University
Title: TBA
Dec 6
-----
Speaker: Tom Wanner, George Mason University
Title:
SPRING 2007
Feb 7
-----
Speaker: Dan Goldman, Georgia Tech
Feb 14
------
Feb 21
------
Speaker: Leslie Smith, Univ of Wisconsin
Title: TBA
Feb 28
------
Mar 6
-----
Mar 13
------
No seminar - APS March meeting
Mar 20
------
No seminar - Spring break
Mar 27 (n)
------
Apr 3 (n)
-----
Apr 10
------
Apr 17 (n)
------
Apr 24
------
May 1
-----
May 8
-----
PRIOR SEMiNAR
Sept 6
------
Speaker: Tom Solomon, Bucknell University
Title: Fronts and patterns in advection-reaction-diffusion
systems.
Host: Dan Lathrop/Matthew Paoletti