Institute for Mathematics and its Applications University of Minnesota 114 Lind Hall 207 Church Street SE Minneapolis, MN 55455 
20092010 Program
See http://www.ima.umn.edu/20092010/ for a full description of the 20092010 program on Complex Fluids and Complex Flows.
20092010 IMA Participating Institutions Conferences
All Day  NSF site visit  
10:45am11:15am  Coffee break  Lind Hall 400 
All Day  NSF site visit  
10:45am11:15am  Coffee break  Lind Hall 400 
1:00pm6:30pm  Board of Governor's Meeting  Lind Hall 409  BOG10.45.09 
All Day  Morning Chair: Matt Feiszli (Yale University) Afternoon Chair: Mario Micheli (University of California, Los Angeles)  SW10.57.09  
8:15am8:45am  Registration and coffee  Lind Hall 305  SW10.57.09  
8:30am2:30pm  Board of Governor's Meeting  Lind Hall 409  BOG10.45.09  
8:45am9:00am  Welcome to the IMA  Fadil Santosa (University of Minnesota)  Lind Hall 305  SW10.57.09 
9:00am9:45am  Local scales in oscillatory patterns and boundaries of objects  Triet Minh Le (Yale University)  Lind Hall 305  SW10.57.09 
9:45am10:30am  Total variation, relaxation & convex optimization for image segmentation & graph clustering  Xavier Bresson (University of California, Los Angeles)  Lind Hall 305  SW10.57.09 
10:30am11:00am  Break  Lind Hall 400  SW10.57.09  
11:00am11:30am  Metric geometry in action: Nonrigid shape acquisition, processing and analysis  Ron Kimmel (TechnionIsrael Institute of Technology)  Lind Hall 305  SW10.57.09 
11:30am12:00pm  Diffeomorphisms and active contours  Laurent Younes (Johns Hopkins University)  Lind Hall 305  SW10.57.09 
12:00pm1:15pm  Lunch  SW10.57.09  
1:15pm2:00pm  Some recent developments in the use of GromovHausdorff and GromovWasserstein metrics  Facundo Mémoli (Stanford University)  Lind Hall 305  SW10.57.09 
2:00pm2:30pm  Learning feature hierarchies with sparse coding  Yann LeCun (New York University)  Lind Hall 305  SW10.57.09 
2:30pm3:00pm  Break  Lind Hall 305  SW10.57.09  
3:00pm3:30pm  Computational conformal geometry and its applications  Xianfeng David Gu (SUNY)  Lind Hall 305  SW10.57.09 
3:30pm4:00pm  Selection of canonical subsets using nonlinear optimization  Ali Shokoufandeh (Drexel University)  Lind Hall 305  SW10.57.09 
4:00pm4:30pm  Government/DoD/Navy talk: Navy needs Automated image understanding  Alan VanNevel (Naval Air Warfare Center)  Lind Hall 305  SW10.57.09 
4:30pm4:40pm  Group Photo  SW10.57.09 
All Day  Morning Chair: Triet Minh Le
(Yale University) Afternoon Chair: Facundo Memoli (Stanford University)  SW10.57.09  
8:30am9:00am  Coffee  Lind Hall 400  SW10.57.09  
9:00am9:45am  Multiscale metrics on plane curves  Matt Feiszli (Yale University)  Lind Hall 305  SW10.57.09 
9:45am10:15am  A fast view of real life video segmentation and a slower view of learning dictionaries for efficient representations  Guillermo R. Sapiro (University of Minnesota)  Lind Hall 305  SW10.57.09 
10:15am10:45am  Break  Lind Hall 400  SW10.57.09  
10:45am11:15am  Stationary features and cat detection  Donald Geman (Johns Hopkins University)  Lind Hall 305  SW10.57.09 
11:15am12:15pm  Modified immersed boundary modeling and simulation of concentrated suspensions  Weigang Zhong (University of Minnesota)  Lind Hall 409  PS 
11:15am11:45am  Sparse subspace clustering  René Vidal (Johns Hopkins University)  Lind Hall 305  SW10.57.09 
11:45am1:15pm  Lunch  SW10.57.09  
1:15pm2:00pm  Sectional curvature of the Riemannian manifold of landmarks  Mario Micheli (University of California, Los Angeles)  Lind Hall 305  SW10.57.09 
2:00pm2:30pm  Robust principal component analysis: Exact recovery of corrupted lowrank matrices via convex optimization  Yi Ma (University of Illinois at UrbanaChampaign)  Lind Hall 305  SW10.57.09 
2:30pm3:00pm  Break  Lind Hall 305  SW10.57.09  
3:00pm3:30pm  Geometry based image processing  a survey of recent results  Andrea L. Bertozzi (University of California, Los Angeles)  Lind Hall 305  SW10.57.09 
3:30pm4:00pm  Nonparametric Bayesian dictionary learning for sparse image representations  Lawrence Carin (Duke University)  Lind Hall 305  SW10.57.09 
4:00pm4:30pm  Government/DoD/Navy Talk  Lind Hall 305  SW10.57.09  
6:30pm8:30pm  Workshop Dinner at Caspian Bistro  Caspian Bistro 2418 University Ave SE Minneapolis, MN 55414 6126231133 
SW10.57.09 
All Day  Chair: Tristan Nguyen (Office of Naval Research)  SW10.57.09  
8:30am9:00am  Coffee  Lind Hall 400  SW10.57.09  
9:00am9:45am  Toward real/interactivetime for l^{1} related problem  Jérôme Darbon (École Normale Supérieure de Cachan)  Lind Hall 305  SW10.57.09 
9:45am10:15am  Clifford algebras and image processing  Michel Berthier (Université de La Rochelle)  Lind Hall 305  SW10.57.09 
10:15am10:45am  Break  Lind Hall 400  SW10.57.09  
10:45am11:15am  Online image processing  JeanMichel Morel (École Normale Supérieure de Cachan)  Lind Hall 305  SW10.57.09 
11:15am11:30am  Closing Remarks  Lind Hall 305  SW10.57.09  
11:15am12:15pm  The generalized hydrodynamic theory  transient elasticity and other examples  Harald Pleiner (Max Planck Institute for Polymer Research)  EE/CS 3180  20092010Seminar 
2:30pm3:20pm  Topics in the theory of the NavierStokes equations  Vladimir Sverak (University of Minnesota)  Lind Hall 305  
3:35pm4:35pm  School of Mathematics, University of Minnesota PDE Seminar  Twist & shout: Maximal enstrophy production in the 3D NavierStokes equations  Charles Doering (University of Michigan)  Vincent Hall 6 
10:45am11:15am  Coffee break  Lind Hall 400  
3:30pm4:30pm  Colloquium: Wellposedness of the full water wave problem in two and three dimensions  Sijue Wu (University of Michigan)  Vincent Hall 16 
10:45am11:15am  Coffee break  Lind Hall 400 
8:30am9:00am  Registration and coffee  EE/CS 3176  T10.11.09  
9:00am10:15am  Fluid dynamics and transport in particulate suspensions I  John F. Brady (California Institute of Technology)  EE/CS 3180  T10.11.09 
10:15am10:30am  Break  EE/CS 3176  T10.11.09  
10:30am11:45am  Fluid dynamics and transport in particulate suspensions II  John F. Brady (California Institute of Technology)  EE/CS 3180  T10.11.09 
11:45am1:30pm  Lunch  T10.11.09  
1:30pm2:45pm  Dynamics of flowing polymer solutions I  Eric S. G. Shaqfeh (Stanford University)  EE/CS 3180  T10.11.09 
2:45pm3:15pm  Break  EE/CS 3176  T10.11.09  
3:15pm4:30pm  Dynamics of flowing polymer solutions II  Eric S. G. Shaqfeh (Stanford University)  EE/CS 3180  T10.11.09 
All Day  Complex flows of complex fluids I Chair: Michael D. Graham (University of Wisconsin, Madison)  W10.1216.09  
8:15am8:45am  Registration and coffee  EE/CS 3176  W10.1216.09  
8:45am9:00am  Welcome to the IMA  Fadil Santosa (University of Minnesota)  EE/CS 3180  W10.1216.09 
9:00am9:40am  Effects of elasticity on high Reynolds number instabilities in TaylorCouette flow  Susan J. Muller (University of California, Berkeley)  EE/CS 3180  W10.1216.09 
9:40am9:45am  Discussion  EE/CS 3180  W10.1216.09  
9:45am10:25am  Nonlinear pattern formation and coherent structure dynamics in viscoelastic Flows  Radhakrishna Sureshkumar (Washington University)  EE/CS 3180  W10.1216.09 
10:25am10:30am  Discussion  EE/CS 3180  W10.1216.09  
10:30am11:00am  Coffee break  EE/CS 3180  W10.1216.09  
11:00am11:40am  Data reduction in viscoelastic turbulent channel flows  Antony N. Beris (University of Delaware)  EE/CS 3180  W10.1216.09 
11:40am11:45am  Discussion  EE/CS 3180  W10.1216.09  
11:45am2:00pm  Lunch  W10.1216.09  
2:00pm2:40pm  Nonmodal amplification of disturbances in channel flows of viscoelastic fluids: A possible route to elastic turbulence?  Satish Kumar (University of Minnesota)  EE/CS 3180  W10.1216.09 
2:40pm2:45pm  Discussion  EE/CS 3180  W10.1216.09  
2:45pm3:25pm  Computing complex flows of complex fluids  Matteo Pasquali (Rice University)  EE/CS 3180  W10.1216.09 
3:25pm3:30pm  Discussion  EE/CS 3180  W10.1216.09  
3:30pm3:40pm  Group Photo  W10.1216.09  
3:40pm4:00pm  Coffee break  EE/CS 3176  W10.1216.09  
4:00pm4:30pm  Second chances  EE/CS 3180  W10.1216.09  
4:30pm6:30pm  Reception and Poster Session Poster submissions welcome from all participants Instructions  Lind Hall 400  W10.1216.09  
Microscale shear flow of focal conic defects in layered liquids  Shelley L. Anna (Carnegie Mellon University)  
Simulation and experiments on selective withdrawal of polymer solutions  James J. Feng (University of British Columbia)  
Multiscale modeling and simulation of fluid flows in deformable porous media  Yuliya Gorb (University of Houston)  
Effective viscosity and dynamics of dilute bacterial suspensions: A threedimensional model  Brian Haines (Pennsylvania State University)  
An O(N) iterative scheme for viscoelastic flow simulations with DEVSS  Oliver Harlen (University of Leeds)  
Numerical prediction of the dynamics of nanoparticles embedded in a liquid crystalline solvent  Juan Pablo HernandezOrtiz (National University of Colombia)  
Simulation of particle migration in viscoelastic fluids using the extended finite element method  Martien A. Hulsen (Technische Universiteit Eindhoven)  
A maximum entropy principle based closure method and hysteresis for macromicro models of polymeric materials  Yunkyong Hyon (University of Minnesota)  
Teaching rheology using product design  Christopher Macosko (University of Minnesota)  
Human tear film dynamics on an eyeshaped domain  Kara Lee Maki (University of Minnesota)  
Structural instability in sedimentation through viscoelastic fluids  Ronald Phillips (University of California, Davis)  
Spherical bubble collapse in viscoelastic fluids  Tim Phillips (Cardiff University)  
Purelyelastic instabilities in extensional flows  Rob Poole (University of Liverpool)  
The response of a hydrophobic superparamagnetic ferrofluid droplet suspended in a viscous fluid in a uniform magnetic field: the influence of microstructure on interfacial tension  Yuriko Renardy (Virginia Polytechnic Institute and State University)  
Efficient numerical computation of fluid interfaces with soluble surfactant: a viscous drop  Michael S. Siegel (New Jersey Institute of Technology)  
Planar extensional motion of an inertiallydriven liquid sheet  Linda B. Smolka (Bucknell University)  
Hydrodynamic pattern formation in ultrathin metal films: Robust route to plasmonic nanomaterials  Radhakrishna Sureshkumar (Washington University)  
A thermodynamically compatible rate type fluid to describe the response of asphalt  Karel Tuma (Charles University in Prague)  
Complex motions of vesicles and red blood cells in flow  Petia M. Vlahovska (Dartmouth College)  
Shape optimization of peristaltic pumping  Shawn W. Walker (New York University)  
Validity and limitations of the statistical scaling hypothesis for a nematic liquid crystal flow  Arghir Dani Zarnescu (University of Oxford) 
All Day  Complex flows of complex fluids II Chair: Gareth Huw Mckinley (Massachusetts Institute of Technology)  W10.1216.09  
8:30am9:00am  Coffee  EE/CS 3176  W10.1216.09  
9:00am9:40am  The effects of polymer molecular weight on filament thinning & drop breakup in microchannels  Paulo E. Arratia (University of Pennsylvania)  EE/CS 3180  W10.1216.09 
9:40am9:45am  Discussion  EE/CS 3180  W10.1216.09  
9:45am10:25am  Mixing and instability in two complex fluid flows  Michael J. Shelley (New York University)  EE/CS 3180  W10.1216.09 
10:25am10:30am  Discussion  EE/CS 3180  W10.1216.09  
10:30am11:00am  Coffee break  EE/CS 3180  W10.1216.09  
11:00am11:40am  The dynamics and stability of viscoelastic wormlike micelle solutions in strong extensional flows  Jonathan P. Rothstein (University of Massachusetts)  EE/CS 3180  W10.1216.09 
11:40am11:45am  Discussion  EE/CS 3180  W10.1216.09  
11:45am1:30pm  Lunch  W10.1216.09  
1:30pm2:10pm  Instabilities due to microstructure growth at fluid interfaces  Andrew Belmonte (Pennsylvania State University)  EE/CS 3180  W10.1216.09 
2:10pm2:15pm  Discussion  EE/CS 3180  W10.1216.09  
2:15pm2:55pm  Modeling the inhomogeneous response in transient shearing and extensional flows of entangled/micellar solutions  L. Pamela Cook (University of Delaware)  EE/CS 3180  W10.1216.09 
2:55pm3:00pm  Discussion  EE/CS 3180  W10.1216.09  
3:00pm3:30pm  Coffee break  EE/CS 3176  W10.1216.09  
3:30pm4:10pm  Shear alignment and mechanical properties of nanostructured hydrogels  Lynn M. Walker (Carnegie Mellon University)  EE/CS 3180  W10.1216.09 
4:10pm4:15pm  Discussion  EE/CS 3180  W10.1216.09  
4:15pm4:45pm  Second chances  EE/CS 3180  W10.1216.09 
All Day  Mathematical analysis and numerical methods for flowing
complex fluids Chair: L. Pamela Cook (University of Delaware)  W10.1216.09  
8:30am9:00am  Coffee  EE/CS 3176  W10.1216.09  
9:00am9:40am  Mathematical issues in stability of viscoelastic flows  Michael Renardy (Virginia Polytechnic Institute and State University)  EE/CS 3180  W10.1216.09 
9:40am9:45am  Discussion  EE/CS 3180  W10.1216.09  
9:45am10:25am  LatticeBoltzmann methods for polymer solutions  A comparison with Brownian dynamics  Tony Ladd (University of Florida)  EE/CS 3180  W10.1216.09 
10:25am10:30am  Discussion  EE/CS 3180  W10.1216.09  
10:30am11:00am  Coffee break  EE/CS 3180  W10.1216.09  
11:00am11:40am  Numerical investigation of drop deformation in shear  Yuriko Renardy (Virginia Polytechnic Institute and State University)  EE/CS 3180  W10.1216.09 
11:40am11:45am  Discussion  EE/CS 3180  W10.1216.09  
11:45am1:30pm  Lunch  W10.1216.09  
1:30pm2:10pm  Complex Fluids: an abstract framework, some analysis, many open problems  Peter Constantin (University of Chicago)  EE/CS 3180  W10.1216.09 
2:10pm2:15pm  Discussion  EE/CS 3180  W10.1216.09  
2:15pm2:55pm  The role of free energy in the mathematical and numerical analysis of complex fluids models  Claude Le Bris (CERMICS)  EE/CS 3180  W10.1216.09 
2:55pm3:00pm  Discussion  EE/CS 3180  W10.1216.09  
3:00pm3:30pm  Coffee break  EE/CS 3176  W10.1216.09  
3:30pm4:10pm  Continuummicroscopic computational modeling of nonequilibrium viscoelastic flow  Sorin Mitran (University of North Carolina)  EE/CS 3180  W10.1216.09 
4:10pm4:15pm  Discussion  EE/CS 3180  W10.1216.09  
4:15pm4:45pm  Second chances  EE/CS 3180  W10.1216.09 
All Day  Complex interfacial and multiphase flows Chair: Andrew M. Kraynik (Sandia National Laboratories)  W10.1216.09  
8:30am9:00am  Coffee  EE/CS 3176  W10.1216.09  
9:00am9:40am  Single particle motion in colloids: Microrheology and microdiffusivity  John F. Brady (California Institute of Technology)  EE/CS 3180  W10.1216.09 
9:40am9:45am  Discussion  EE/CS 3180  W10.1216.09  
9:45am10:25am  Foam structure and rheology: The shape and feel of random soap froth  Andrew M. Kraynik (Sandia National Laboratories)  EE/CS 3180  W10.1216.09 
10:25am10:30am  Discussion  EE/CS 3180  W10.1216.09  
10:30am11:00am  Coffee break  EE/CS 3180  W10.1216.09  
11:00am11:40am  Particle pressureinduced phenomena in suspensions: from osmosis to granular dilation  Jeffrey F. Morris (City College, CUNY)  EE/CS 3180  W10.1216.09 
11:40am11:45am  Discussion  EE/CS 3180  W10.1216.09  
11:45am1:30pm  Lunch  W10.1216.09  
1:30pm2:10pm  Jet breakup of polymer solutions in inkjet printing  Oliver Harlen (University of Leeds)  EE/CS 3180  W10.1216.09 
2:10pm2:15pm  Discussion  EE/CS 3180  W10.1216.09  
2:15pm2:55pm  Moving contact lines and enhanced slip on textured substrates  James J. Feng (University of British Columbia)  EE/CS 3180  W10.1216.09 
2:55pm3:00pm  Discussion  EE/CS 3180  W10.1216.09  
3:00pm3:30pm  Coffee break  EE/CS 3176  W10.1216.09  
3:30pm4:10pm  Polymeric threads: formation and instability  Jens Eggers (University of Bristol)  EE/CS 3180  W10.1216.09 
4:10pm4:15pm  Discussion  EE/CS 3180  W10.1216.09  
4:15pm4:45pm  Second chances  EE/CS 3180  W10.1216.09  
6:30pm8:30pm  Workshop Dinner at Pagoda  Pagoda Restaurant 1417 4th St. SE Minneapolis, MN 6123784710 
W10.1216.09 
All Day  Mesoscale and multiscale computational simulations of
flowing complex fluids Chair: John F. Brady (Caltech)  W10.1216.09  
8:15am8:30am  Coffee  EE/CS 3176  W10.1216.09  
8:30am9:10am  Mesoscopic simulation of the dynamics of confined complex fluids  Michael D. Graham (University of Wisconsin)  EE/CS 3180  W10.1216.09 
9:10am9:15am  Discussion  EE/CS 3180  W10.1216.09  
9:15am9:55am  Modeling and simulation of complex fluids via field theory  Hector D. Ceniceros (University of California, Santa Barbara)  EE/CS 3180  W10.1216.09 
9:55am10:00am  Discussion  EE/CS 3180  W10.1216.09  
10:00am10:15am  Coffee break  EE/CS 3176  W10.1216.09  
10:15am10:55am  Stochastic EulerianLagrangian methods for fluidstructure interactions with thermal fluctuations  Paul J. Atzberger (University of California, Santa Barbara)  EE/CS 3180  W10.1216.09 
10:55am11:00am  Discussion  EE/CS 3180  W10.1216.09  
11:00am11:40am  Dissipative particle dynamics: Algorithms and recent applications  Bruce Caswell (Brown University)  EE/CS 3180  W10.1216.09 
11:40am11:45am  Discussion  EE/CS 3180  W10.1216.09  
11:45am1:30pm  Lunch  W10.1216.09  
1:30pm2:10pm  Kinetic theories for complex fluids  Qi Wang (University of South Carolina)  EE/CS 3180  W10.1216.09 
2:10pm2:15pm  Discussion  EE/CS 3180  W10.1216.09  
2:15pm2:55pm  A seamless algorithm for multiscale simulations  Weiqing Ren (New York University)  EE/CS 3180  W10.1216.09 
2:55pm3:00pm  Discussion  EE/CS 3180  W10.1216.09  
3:00pm3:30pm  Second chances and closing remarks  EE/CS 3180  W10.1216.09 
10:45am11:15am  Coffee break  Lind Hall 400  
2:30pm3:20pm  Topics in the theory of the NavierStokes equations  Vladimir Sverak (University of Minnesota)  Lind Hall 305 
10:45am11:15am  Coffee break  Lind Hall 400  
11:15am12:15pm  Identifying, characterizing and modeling coherent structures of turbulent boundary layers  Cecilia OrtizDuenas (University of Minnesota)  Lind Hall 305  PS 
10:45am11:15am  Coffee break  Lind Hall 400  
11:15am12:15pm  Transition in inertialess flows of viscoelastic fluids: the role of uncertainty  Mihailo Jovanovic (University of Minnesota)  Lind Hall 305  20092010Seminar 
2:30pm3:20pm  Topics in the theory of the NavierStokes equations  Vladimir Sverak (University of Minnesota)  Lind Hall 305 
10:45am11:15am  Coffee break  Lind Hall 400 
10:45am11:15am  Coffee break  Lind Hall 400  
1:25pm2:25pm  Optimization algorithms for applications in industry  Todd Plantenga (Sandia National Laboratories)  Vincent Hall 570  IPS 
10:45am11:15am  Coffee break  Lind Hall 400  
2:30pm3:20pm  Topics in the theory of the NavierStokes equations  Vladimir Sverak (University of Minnesota)  Lind Hall 305 
10:45am11:15am  Coffee break  Lind Hall 400  
11:15am12:15pm  Thorough analysis of the Oseen system in 2D exterior domains  Pawel Konieczny (University of Minnesota)  Lind Hall 305  PS 
10:45am11:15am  Coffee break  Lind Hall 400 
10:45am11:15am  Coffee break  Lind Hall 400 
1:30pm2:30pm  Pumpkin painting and treats Contact Michelle Radtke, 69886 (radtke@ima.umn.edu) for further information on this event.  Lind Hall 400 
Event Legend: 

20092010Seminar  IMA Seminar on Complex Fluids and Complex Flows 
BOG10.45.09  Board of Governor's Meeting 
IPS  Industrial Problems Seminar 
PS  IMA Postdoc Seminar 
SW10.57.09  Research in Imaging Sciences 
T10.11.09  From Microscopic to Macroscopic Fluid Dynamics in Complex Fluids 
W10.1216.09  Flowing Complex Fluids: Fluid MechanicsInteraction of Microstructure and Flow 
Second chances  
Abstract: No Abstract  
Second chances  
Abstract: No Abstract  
Second chances  
Abstract: No Abstract  
Second chances  
Abstract: No Abstract  
Second chances and closing remarks  
Abstract: No Abstract  
Shelley L. Anna (Carnegie Mellon University)  Microscale shear flow of focal conic defects in layered liquids 
Abstract: Intermolecular interactions in liquid crystals and concentrated surfactant solutions lead to unique microstructures including lamellae, in which parallel layers are incompressible but bend easily. In such systems, planar layers are easily destabilized via external fields and nearby surfaces to produce topological defects of the order of tens of microns in size. These microscopic defects play a leading role in the flow behavior of such materials, and therefore impact numerous industrial applications including optoelectronic devices and displays and the processing of coatings, adhesives, and biomaterials to encapsulate drugs. To examine the interaction between such microscale defects and flow, we have developed a shear cell to impose a linear Couette flow in a microscale thin gap, while allowing for real time microscopic visualization. We use the shear cell to visualize the dynamics of defect formation in initially defectfree samples of a common smallmolecule thermotropic liquid crystal, 8CB. We observe that the formation of focal conic defects, a specific topological defect typically found in thermotropic smectic liquid crystals, is triggered by edge effects and occurs in a series of phases, marked by distinct changes in the birefringence intensity. The defects are seen to annihilate partially or completely on reverse shear. The effect of shear rate and strain amplitude on defect formation and annihilation is studied.  
Paulo E. Arratia (University of Pennsylvania)  The effects of polymer molecular weight on filament thinning & drop breakup in microchannels 
Abstract: In this talk, the effects of fluid elasticity on the dynamics of filament thinning and drop breakup processes are investigated in a crossslot microchannel. Elasticity effects are examined using dilute aqueous polymeric solutions of molecular weight (MW) ranging from 1.5 x 10(^3) to 1.8 × 10(^7). Results for polymeric fluids are compared to those for a viscous Newtonian fluid. The shearing or continuous phase that induces breakup is mineral oil. All fluids possess similar shearviscosity (~0.2 Pa s) so that the viscosity ratio between the oil and aqueous phases is close to unity. Measurements of filament thickness as a function of time show different thinning behavior for the different aqueous fluids. For Newtonian fluids, the thinning process shows a single exponential decay of the filament thickness. For low MW fluids (10^{3}, 10^{4}, and 10^{5}), the thinning process also shows a single exponential decay, but with a decay rate that is slower than for the Newtonian fluid. The decay time increases with polymer MW. For high MW (10^{6} and 10^{7}) fluids, the initial exponential decay crosses over to a second exponential decay in which elastic stresses are important. We show that the decay rate of the filament thickness in this exponential decay regime can be used to measure the steady extensional viscosity of the fluids. At late times, all fluids cross over to an algebraic decay which is driven mainly by surface tension.  
Paul J. Atzberger (University of California, Santa Barbara)  Stochastic EulerianLagrangian methods for fluidstructure interactions with thermal fluctuations 
Abstract: Keywords: Statistical Mechanics, Soft Condensed Materials, Stochastic Eulerian Lagrangian Methods, Fluid Dynamics. Abstract: A modeling and simulation formalism is presented for the study of soft materials. The formalism takes into account microstructure elasticity, hydrodynamic interactions, and thermal fluctuations. As a specific motivation we consider lipid bilayer membranes and polymeric fluids. The approach couples a Lagrangian description of the microstructures (lipid molecules / polymers) with an Eulerian description of the hydrodynamics. Thermal fluctuations are incorporated in the formalism by an appropriate stochastic forcing of the resulting equations in accordance with the principles of statistical mechanics. The overall approach extends previous work on the Stochastic Immersed Boundary Method. Simulation studies are presenting showing applications of the methodology in the study of lipid flow in bilayer membranes, the shear viscosity of polymer fluids and lipid structures, and the diffusivity of particles in complex fluids.  
Andrew Belmonte (Pennsylvania State University)  Instabilities due to microstructure growth at fluid interfaces 
Abstract: Keywords: wormlike micelles, hydrodynamic instability, micellar aggregation reactions Abstract: The viscoelasticity of a wormlike micellar fluid derives from the presence at the microscale of long tubelike surfactant aggregations (micelles), which occur at low concentrations due to the presence of an organic salt/cosurfactant. Without this salt the micelles are spherical, and the fluid is completely Newtonian. I will present recent experiments on hydrodynamic instabilities caused or modified by the formation of a viscoelastic micellar layer between two Newtonian liquids containing either the surfactant or the organic salt. The micellar "reaction" produces a fragile material which grows in competition with local stretching or advection at the interface, leading to new effects in HeleShaw fingering, in droplet sedimentation, and in microfluidic emulsions.  
Antony N. Beris (University of Delaware)  Data reduction in viscoelastic turbulent channel flows 
Abstract: Direct Numerical Simulations (DNS) of turbulent viscoelastic channel flows typically generate a tremendous volume of information (terabytes per run. Data reduction is therefore essential in order to allow for an efficient processing of the data, let alone its preservation for future studies. However, previous attempts, using a projection of the velocity to the top KarhunenLoeve (KL) modes, failed to produce velocity fields that could generate the DNS conformation field adequately. In an effort to rectify this deficiency we investigate here three different approaches that attempt to introduce small scale information. First, we extended the KL analysis that allowed us to use a hybrid measure, based on a weight of the pseudodissipation and the fluctuating kinetic energy, as a new objective function. Second, we used a KL decomposition of the vorticity field using the enstrophy (average of the square of vorticity fluctuations) as our new objective function. As a third attempt, we used again the standard velocity KL approach, but in the reconstruction stage of the conformation tensor we compensated by suitably rescaling the Weissenberg number. It is shown here that, whereas the first two methods fail to give any improvement over the classical KL approach, we were able to reconstruct fairly accurately the conformation field using the third approach, even with a relatively small set of 1714 KL modes. The rescaling factor in that method was calculated objectively, based on the ratio of DNS vs. KLreconstructed based estimates of the extensional deformation rate in the buffer layer. Given that fact, we hope that this approach can also provide the starting point for future investigations into lowdimensional modeling of viscoelastic turbulence as well as other multiscale applications.  
Michel Berthier (Université de La Rochelle)  Clifford algebras and image processing 
Abstract: Keywords: Geometric and Clifford Algebras, Image and Signal Processing, Segmentation, Diffusion, Differential Geometry for Image Processing.
Abstract:
Since the seminal work of Hestenes, Clifford algebras (also called geometric algebras) appeared to be a powerful tool
for geometric modeling in theoretical physics. During the last years, the socalled "geometric calculus" has found many
applications in computer science, especially in vision and robotics (Lasenby, Bayro Corrochano, Dorst ...). Concerning
image processing, Clifford algebras were already used implicitly by Sangwine through the coding of color with quaternions.
The aim of this talk is first to give basic notions about these algebras and the related spinor groups. I will then detail two
applications : a metric approach for edge detection in nD images and the construction of a Clifford Hodge operator that
generalizes the Beltrami operator of Sochen et al. This latter can be used for diffusion in color images but also for diffusion
of vector and orthonormal frame fields. The geometric framework of these applications is the one of fiber and Clifford bundles.
Very roughly speaking, the basic idea is to take advantage of embedding an acquisition space in a higher dimensional algebra
containing elements of different kinds and related to a specified metric. If time remains, I will also mention in few words applications
for signal processing (Clifford Fourier transform and color monogenic signal).
Two basic references :
Math.: Chevalley, C.: The Algebraic Theory of Spinors and Clifford Algebras, new edn. Springer (1995) Computer Science: Sommer, G.: Geometric Computing with Clifford Algebras. Theoretical Fundations and Applications in Computer Vision and Robotics. Springer, Berlin (2001) 

Andrea L. Bertozzi (University of California, Los Angeles)  Geometry based image processing  a survey of recent results 
Abstract: Keywords: geometry, image processing, diffuse interface, sparse representations, pan sharpening Abstract: I will present a survey of recent results on geometrybased image processing. The topics will include waveletbased diffuse interface methods, pan sharpening and hyperspectral sharpening, and sparse image representation.  
John F. Brady (California Institute of Technology)  Fluid dynamics and transport in particulate suspensions I 
Abstract: No Abstract  
John F. Brady (California Institute of Technology)  Fluid dynamics and transport in particulate suspensions II 
Abstract: No Abstract  
John F. Brady (California Institute of Technology)  Single particle motion in colloids: Microrheology and microdiffusivity 
Abstract: Keywords: Colloidal dispersions, Brownian motion, rheology Abstract: The motion of a single individual particle in a complex material is fundamental to understanding the dynamical properties of the material. Monitoring such motion has given rise to a suite of experimental techniques collectively known as ‘microrheology,’ with the ability to probe the viscoelastic properties of soft heterogeneous materials (e.g. polymer solutions, colloidal dispersions, biomaterials, etc.) at the micrometer (and smaller) scale. In microrheology, elastic and viscous moduli are obtained from measurements of the fluctuating thermal motion of embedded colloidal probes. In such experiments, the probe motion is passive and reflects the nearequilibrium (linear response) properties of the surrounding medium. By actively pulling the probe through the material one can gain information about the nonlinear response, analogous to largeamplitude measurements in macrorheology. But what exactly is measured in a microrheological experiment? And how does the microrheological response compare with conventional macrorheology? To answer these questions, we consider a simple model – a colloidal probe pulled through a suspension of neutrally buoyant bath colloids – for which both micro and macroresults can be obtained exactly. The moving probe distorts the dispersion’s microstructure resulting in a reactive entropic or osmotic force that resists the probe’s motion, which can be calculated analytically and via Brownian Dynamics simulations and used to infer the dispersion's 'effective microviscosity.' By studying the fluctuations in the probe’s motion we can also determine the forceinduced 'microdiffusivity.' Connections between micro and macro behavior will be explored.  
Xavier Bresson (University of California, Los Angeles)  Total variation, relaxation & convex optimization for image segmentation & graph clustering 
Abstract: Keywords: Image segmentation, MumfordShah model, graph clustering, relaxation method, total variation, operator splitting technique, normalized cut, Cheeger cut. Abstract: In this talk, I will introduce two algorithms for image segmentation and graph clustering. One of the most influential image segmentation models is the MumfordShah’s model. Several algorithms such as the level set method have been introduced to compute a minimizing solution to the MS’s problem, but none of them can compute a global solution. We introduce a convex formulation for the multiphase piecewise constant MS problem (which is equivalent to the NPhard problem of Potts in the discrete literature) and compute exact global minimizing solutions. We believe our method is the first in the literature that can make this claim. The second model will focus on graph clustering, which aims at grouping similar highdimensional data s.a. images. The main problem of graph clustering is to minimize a cut of a graph. Popular cuts are the normalized cut of ShiMalik and the Cheeger’s cut, which are NPhard problems. We introduce a continuous relaxation of the Cheeger’s cut problem and we show that the relaxation is actually equivalent to the original problem, which is not the case with the ShiMalik’s relaxation. We also give an algorithm which is experimentally efficient on some clustering benchmarks since the algorithm can cluster 10,000 highdimensional points in a few seconds. This is joint work with T.F. Chan, E. Brown (UCLA) and A. Szlam (NYU).  
Lawrence Carin (Duke University)  Nonparametric Bayesian dictionary learning for sparse image representations 
Abstract: Nonparametric Bayesian techniques are considered for learning dictionaries for sparse image representations, with applications in denoising, inpainting and compressive sensing (CS). The beta process is employed as a prior for learning the dictionary, and this nonparametric method naturally infers an appropriate dictionary size. The Dirichlet process and a probit stickbreaking process are also considered to exploit structure within an image. The proposed method can learn a sparse dictionary in situ; training images may be exploited if available, but they are not required. Further, the noise variance need not be known, and can be nonstationary. Another virtue of the proposed method is that sequential inference can be readily employed, thereby allowing scaling to large images. Several example results are presented, using both Gibbs and variational Bayesian inference, with comparisons to other stateoftheart approaches.  
Bruce Caswell (Brown University)  Dissipative particle dynamics: Algorithms and recent applications 
Abstract: In its original version the governing equations of Dissipative Particle Dynamics (DPD) contain three forces which need to be specified in any application, namely: i. a conservative soft repulsion, ii. a random force, iii. a dissipative force. The required thermostat is enforced by balance of ii. and iii. through the FluctuationDissipation theorem . With about 3 to 4 thousand particles (number densities of 3 to 4) these forces simulate a nearly incompressible fluid whose compressibility is close to water’s, and whose viscosity is constant. When the latter is combined with the selfdiffusion coefficient a characteristic radius of the DPD particle can be calculated from the StokesEinstein relation. Drag force calculations on single DPD particles imersed in a streaming flow show consistency with Stokes law as the Schmidt numbe increases from one. Thus DPD particles are mesoscopic entities, and are hydrodynamically similar to the beads of Brownian Dynamics (BD). However, the hydrodynamic forces between DPD particles are implicit. Complex fluids such as polymers are modeled by connecting DPD particles with spring forces. Examples include dilute, concentrated and undiluted beadspring chains in plane Couette and in Poiseulle flow which are simulated with periodic boundary conditions. Real boundaries require carefull treatment to avoid unphysical density fluctuations near a wall. Another application of DPD is in the ‘tripple decker’ which attemps to match regions described by continuum, DPD, and Molecular Dynamics (MD) respectively. In the original DPD all forces on a particle are central which obviates the need to deal with angular momentum. However, the calculated rotational drag on a single DPD particle was found to deveate subtantially from the Stokes value. The remedy adds a noncentral term to the dissipative force, and includes angular momentum explicitly. The new formulation has been used to simulate a colloidal suspension of large hard DPDparticles in a solvent of soft DPD particles. The results show the model to be economical, and to exhibit the same features as those obtained by the Stokesian dynamics method. A more complex case is the red blood cell (RBC) model with a membrane constructed from DPD particles connected by nonlinear springs and with an extra dissipative force to describe the known viscolelastic properties of the RBC membrane. This model succeeds in describing quantitatively a number of static and dynamic experiments without adjustment of parameters. The models described above have been developed empirically by intuition. A more rigorous and difficult approach is to attempt to derive DPD from analysis at the molecular level. To this end MD simulations of LennardJonesium (LJ) are interpreted statistically for clusters of O(10) LJ molecules to derive the soft potentials and also the dissipative forces which are found generally to be noncentral.  
Hector D. Ceniceros (University of California, Santa Barbara)  Modeling and simulation of complex fluids via field theory 
Abstract: Keywords: Field theoretic polymer models, flowstructure interaction, mesoscale models, phase field models. Abstract: We will present examples of field theoretic models of multicomponent and complex fluids and discuss their main computational challenges and recent advances. We will start with simple phase field based models and progress to a class of fieldtheoretic models that incorporate exact thermodynamics. In particular, we will present a model for an inhomogeneous melt of elastic dumbbell polymers which incorporates thermodynamic forces acting on the polymers into the hydrodynamic equations. The resulting equations are composed of a system of fourth order PDEs coupled with a nonlinear optimization problem to determine the conjugate fields. We develop a semiimplicit numerical method for the resulting system of PDE's in addition to a parallel nonlinear optimization solver for the conjugate meanfields. The semiimplicit method effectively removes the fourth order stability constraint associated with explicit methods and we observe a first order timestep restriction. The algorithm for solving the nonlinear optimization problem, which takes advantage of the form of the operators being optimized, reduces the overall computational cost of simulations by several orders of magnitude.  
Peter Constantin (University of Chicago)  Complex Fluids: an abstract framework, some analysis, many open problems 
Abstract: Keywords: optimal transportation theory, nonlinear FokkerPlanck equations, gradient systems in metric space, Onsager equation Abstract: I will describe a framework for the study of the time evolution of probability distributions of complex systems based on ideas of optimal transportation theory and gradient systems in metric spaces.  
L. Pamela Cook (University of Delaware)  Modeling the inhomogeneous response in transient shearing and extensional flows of entangled/micellar solutions 
Abstract: Surfactant molecules (micelles) can selfassemble in solution into long flexible structures known as wormlike micelles. These structures entangle, forming a dense network and thus exhibit viscoelastic effects, similar to entangled polymer melts. In contrast to 'inert' polymeric networks, wormlike micelles continuously break and reform leading to an additional relaxation mechanism and the name 'living polymers.' Experimental studies show that, in shearing flows, wormlike micellar solutions exhibit spatial inhomogeneities, or shear bands. The VCM model, a twospecies elastic network model was formulated to capture, in a selfconsistent manner, the micellar breakage and reforming. This model consists of a coupled set of partial differential equations describing the breakage and reforming of two micellar species (a long species 'A' and a shorter species ‘B’)  in addition to reptative and Rousian stressrelaxation mechanisms. Transient and steadystate calculations of the full inhomogeneous flow field show localized shear bands that grow linearly in spatial extent across the gap as the apparent shear rate is incremented. This model also captures the nonmonotonic variation in the steady state elongational viscosity that has been reported experimentally and the marked differences between the response of micellar solutions in biaxial and uniaxial extensional flows. The nonmonotonic variation in the extensional viscosity has important dynamical consequences in transient elongational flows; In filament stretching experiments designed to measure the extensional rheology of wormlike micelle solutions, it has been observed that the elongating filaments may suddenly rupture near the axial midplane at high strain rates [Rothstein]. This newlyobserved failure mechanism is not related to the viscocapillary thinning observed in viscous Newtonian fluids. Results of timedependent simulations with the model carried out in a slender filament formulation appropriate for elongational flows of complex fluids are presented. The simulations show that elongating filaments described by the VCM model exhibit a dramatic and sudden rupture event similar to that observed in experiments. This instability is purely elastic in nature (i.e. it is not driven by capillarity) but arises from coupling between the evolution in the tensile stress and the number density of the entangled species. The dynamics of this localized necking are contrasted with predictions of other nonlinear viscoelastic models.  
Jérôme Darbon (École Normale Supérieure de Cachan)  Toward real/interactivetime for l^{1} related problem 
Abstract: Keywords: Parallel Programming, optimization, l^{1} Abstract: We consider the recovery of signal via compressive sensing where the signal itself or its gradient are assumed to be sparse. This amounts to solve a l^{1} or a Total Variation minimization problem. We propose minimization algorithms specifically designed to take advantage of shared memory, vectorized, parallel and manycore microprocessors such as the Cell processor, new generation Graphics Processing Units (GPUs) and standard vectorized multicore processors (e.g. standard quad core CPUs).  
Charles Doering (University of Michigan)  School of Mathematics, University of Minnesota PDE Seminar  Twist & shout: Maximal enstrophy production in the 3D NavierStokes equations 
Abstract: It is still not known whether solutions to the 3D NavierStokes equations for incompressible flows in a finite periodic box can become singular in finite time. (This question is the subject of one of the $1M Clay Prize problems.) It is known that a solution remains smooth as long as the enstrophy, i.e., the meansquare vorticity, of the solution is finite. The generation rate of enstrophy is given by a functional that can be bounded using elementary functional estimates. Those estimates establish shorttime regularity but do not rule out finitetime singularities in the solutions. In this work we formulate and solve the variational problem for the maximal growth rate of enstrophy and display flows that generate enstrophy at the greatest possible rate. Implications for questions of regularity or singularity in solutions of the 3D NavierStokes equations are discussed. This is joint work with Lu Lu, Indiana University Mathematics Journal Vol. 57, pp. 26932727 (2008).  
Jens Eggers (University of Bristol)  Polymeric threads: formation and instability 
Abstract: We report on recent experimental and theoretical work on the pinchoff of dilute solutions of flexible polymers. Owing to the strong extensional hardening of such solutions, pinchoff of a liquid drop is delayed. Instead, long threads of uniform thickness form, whose radius decreases exponentially in time. We derive a relationship between the thread radius and the extensional viscosity. When the thread radius has decreased to about 10 microns, the thread becomes unstable to the rapid growth of small ``blisters''. Observations are in strong disagreement with conventional models for dilute suspensions. The ensuing dynamics are very rich, and include iterated instabilities and periodic ``breathing''. For sufficiently high polymer concentrations, the fluid never breaks, and a solid nanometersized thread is left behind.  
Matt Feiszli (Yale University)  Multiscale metrics on plane curves 
Abstract: Keywords: conformal, metric, shape, curves, harmonic, multiscale Abstract: We will present several families of metrics on plane curves, each of which is based on some multiscale representation and is equivalent to a Sobolevtype norm. These metrics arise when trying to characterize local regularity of functions and curves. The underlying techniques are borrowed from harmonic and complex analysis. We will present theoretical and practical results; in particular we will show experimental results on the MPEG7 Shape 1b test dataset.  
James J. Feng (University of British Columbia)  Moving contact lines and enhanced slip on textured substrates 
Abstract: I will discuss the use of a diffuseinterface model for simulating moving contact lines. The CahnHilliard diffusion is known to regularize the singularity and makes possible a continuumlevel computation. But relating the results to physical reality is subtle. I will show numerical results that suggest a welldefined sharpinterface limit, with a finite contact line speed that can be related to measurements. Furthermore, I will discuss applications of this model to simulate enhanced slip on textured substrates due to contact line depinning, with viscous or viscoelastic liquids.  
James J. Feng (University of British Columbia)  Simulation and experiments on selective withdrawal of polymer solutions 
Abstract: Selective withdrawal refers to the removal of stratified fluids by a suction tube placed near the interface. We view this as an interesting complex fluid flow problem since the interface is disturbed by the nearby sink flow, and the interfacial morphology depends on the bulk rheology of the fluids. The poster will show recent numerical and experimental results for the selective withdrawal of polymer solutions. The most notable result is a transition from a smooth continuous interface to one with a thin air jet emanating from the tip of the interface, reminiscent of the Taylor cone.  
Donald Geman (Johns Hopkins University)  Stationary features and cat detection 
Abstract: Keywords: object detection, invariant features, hierarchical search Abstract: This talk is about research in scene interpretation. Most algorithms for detecting and describing instances from object categories consist of looping over a partition of a "pose space" with dedicated binary classifiers. This strategy is inefficient for a complex pose: fragmenting the training data severely reduces accuracy, and the computational cost is prohibitive due to visiting a massive pose partition. To overcome datafragmentation I will discuss a novel framework centered on poseindexed features, which allows for efficient, oneshot learning of posespecific classifiers. Such features are designed so that the probability distribution of the response is invariant if an object is actually present. I will illustrate these ideas by detecting and localizing cats in highly cluttered greyscale scenes. This is joint work with Francois Fleuret.  
Yuliya Gorb (University of Houston)  Multiscale modeling and simulation of fluid flows in deformable porous media 
Abstract: The main focus of the current poster presentation is on fluid flows in deformable elastic media and associated multiscale problems. Many upscaling methods are developed for flows in rigid porous media or deformable elastic media assuming infinitely small fluidsolid interface displacements relative to the pore size. Much research is needed for the most general and least studied problem of flow in deformable porous media when the fluidsolid interface deforms considerably at the pore level. We introduce a general framework for numerical upscaling of the deformable porous media in the context of a multiscale finite element method. This method allows for large interface displacements and significant changes in pore geometry and volume. For linear elastic solids we present some analysis of the proposed method.  
Michael D. Graham (University of Wisconsin)  Mesoscopic simulation of the dynamics of confined complex fluids 
Abstract: Keywords: Microfluidics, polymer solutions, Brownian dynamics, blood flow Abstract: Many interesting and important phenomena in flowing complex fluids arise when the length scale of the microstructure becomes comparable with the length scale of the flow geometry. This is the case, for example, for solutions of genomic DNA in a microfluidic device or blood in the microcirculation. We describe here an efficient computational framework, based on a new realspace particleparticle/particlemesh approach to solution of Stokes equations, for performing Brownian dynamics simulations of polymer solutions in micronscale geometries and use them to illustrate and understand hydrodynamic migration phenomena of DNA in these geometries. The methodology will also be combined with a novel immersed boundary method for elastic capsules in Stokes flow. With this approach, we take some initial steps toward understanding the observed beneficial effects that addition of dragreducing polymers have on blood flow.  
Xianfeng David Gu (SUNY)  Computational conformal geometry and its applications 
Abstract: Keywords: Conformal, Ricci flow, Hodge, Teichmuller, Riemann surface Abstract: Conformal mappings are anglepreserving mappings. All closed surfaces can be conformally mapped to one of three canonical spaces: the sphere, the plane or the hyperbolic disk. All surfaces with boundaries can be mapped to the canonical spaces with circular holes. The computational algorithms for finding such mappings will be explained. Two surfaces are conformally equivalent if they can be mapped to each other by a conformal mapping. All conformal equivalence classes form a finite dimensional Riemannian manifold, the socalled Teichmuller space. Teichmuller space is a natural shape space model. The algorithm for computing Teichmuller coordinates for each surface will be introduced. The computational algorithms are based on Ricci flow, which refers to the process of deforming Riemannian metric proprotional to curvature, such that curvature evolves according to a heat diffusion. Discrete Ricci flow will be explained in details. The broad applications of conformal geometry in computer graphics, computer vision, medical imaging, and networking will be briefly introduced as well.  
Brian Haines (Pennsylvania State University)  Effective viscosity and dynamics of dilute bacterial suspensions: A threedimensional model 
Abstract: We present a PDE model for dilute suspensions of bacteria in a threedimensional Stokesian fluid. This model is used to calculate the statisticallystationary bulk deviatoric stress and effective viscosity of the suspension from the microscopic details of the interaction of an elongated body with the background flow. A bacterium is modeled as a prolate spheroid with selfpropulsion provided by a point force, which shows up in the model as an inhomogeneous delta function in the PDE. The bacterium is also subject to a stochastic torque in order to model tumbling (random reorientation). Due to a bacterium's asymmetric shape, interactions with a prescribed generic background flow, such as pure shear or planar shear, cause the bacterium to preferentially align in certain directions. Due to the stochastic torque, the steadystate distribution of orientations is unique for a given background flow. Under this distribution of orientations, selfpropulsion produces a reduction in the effective viscosity. For sufficiently weak background flows, the effect of selfpropulsion on the effective viscosity dominates all other contributions, leading to an effective viscosity of the suspension that is lower than the viscosity of the ambient fluid. This is in agreement with recent experiments on suspensions of Bacillus subtilis.  
Oliver Harlen (University of Leeds)  Jet breakup of polymer solutions in inkjet printing 
Abstract: Keywords: dilute polymer solutions, FENE model, free surface flows, Finite Elements Abstract: The effects of polymer additives on the breakup of jets in continuous (CIJ) and drop on demand (DOD) inkjet printing are considered. In continuous inkjet printing the fluid jet is modulated at close to the Rayleigh frequency to produce a steady stream of uniform drops, while in drop on demand printing individual drops are generated by applying an impulse to the fluid. Even at very low concentrations the presence of high molecular weight polymers significantly affects how jets breakup into drops, due to the high extensionrates involved. By simulating these flows with the FENE dumbbell constitutive equation we are able to establish the parameter values controlling the breakup length and character of jet breakup, such as the production of small satellite droplets (which are detrimental to the inkjetting process). For the case of drop on demand printing, we compare our predictions to experimental measurements on dilute solutions of monodisperse polystyrene. By using Zimm theory to predict the parameter values in the FENE model, we are able to demonstrate quantitative agreement between simulations and experiments.  
Oliver Harlen (University of Leeds)  An O(N) iterative scheme for viscoelastic flow simulations with DEVSS 
Abstract: In largescale finite element simulations of timedependent viscoelastic flows the major computational difficulty is the solution of the linear system derived from the momentum and continuity equations. For Newtonian fluids highly efficient iterative solvers have been developed (Elman, Silvester & Wathen "Finite Elements and Fast Iterative Solvers") using block preconditioned Krylov space methods. These methods converge within a fixed number of outer iterations so that both the computational time and memory requirements are proportional to the number of unknowns. Based on these ideas we have developed an iterative scheme for viscoelastic computations discretised using the popular DEVSS (Discrete ElasticViscous Stress Splitting) algorithm. We show that this scheme also converges within a fixed number of outer iterations for both two and three dimensional calculations, allowing large three dimensional calculations to be performed efficiently.  
Juan Pablo HernandezOrtiz (National University of Colombia)  Numerical prediction of the dynamics of nanoparticles embedded in a liquid crystalline solvent 
Abstract: A hierarchical modeling approach has been adopted to examine the structure and dynamics of nanoparticle suspensions in confined liquid crystals. A molecular model and a combination of Monte Carlo and molecular dynamics simulations are used to investigate the defects that arise around the nanoparticles, both at rest and other imposed flow fields, and to explore how such defects influence the aggregation behavior of the particles. The continuum molecular model is solved by resorting to a unsymmetric radial basis function based technique. The validity of the model and our numerical results are established by direct comparison to results of molecular simulations and to experimental mobility data in both the isotropic and nematic phases. The model is then used to examine the response of different types of confinement, surface treatment, and flow field on the aggregation pathways of nanoparticles in liquid crystals.  
Martien A. Hulsen (Technische Universiteit Eindhoven)  Simulation of particle migration in viscoelastic fluids using the extended finite element method 
Abstract: We present an eXtended Finite Element Method (XFEM) combined with a DEVSSG/SUPG formulation for the direct numerical simulation of the flow of viscoelastic fluids with suspended rigid particles. For the whole computational domain including both the fluid and particles, we use a regular mesh which is not boundaryfitted. Then, the fluid domain and the particle domain are fully decoupled by using XFEM enrichment procedures. For moving particle problems, we incorporate a temporary arbitrary LagrangianEulerian (ALE) scheme without the need of any remeshing. We show the motion of a freely moving particle suspended in a Giesekus fluid between two rotating cylinders. The particle migrates to a stabilized radial position near the outer cylinder regardless of its initial position. As the Deborah number increases, the stabilized radial position of the particle shifts toward the outer cylinder.  
Yunkyong Hyon (University of Minnesota)  A maximum entropy principle based closure method and hysteresis for macromicro models of polymeric materials 
Abstract: We consider the finite extensible nonlinear elasticity (FENE) dumbbell model in viscoelastic polymeric fluids. The maximum entropy principle for FENE model is employed to obtain the solution which maximizes the entropy of FENE model in stationary situations. Then the maximum entropy solution is approximated using the second order terms in microscopic configuration field to get an probability density function (PDF). The approximated PDF gives a solution to avoid the difficulties caused by the nonlinearity of FENE model. The momentclosure system satisfies the energy dissipation law. The momentclosure system can also show the hysteresis which is a nonlinear behavior of viscoelastic dilute polymeric fluids. The hysteresis of FENE model can be seen during a relaxation in simple extensional flow employing the normal stress/the elongational viscosity versus the meansquare extension. The hysteretic behaviors of viscoelastic dilute polymeric fluids with momentclosure approximation models, FENEL, FENEP, FENED, are presented in extensional/enlongational flows.  
Mihailo Jovanovic (University of Minnesota)  Transition in inertialess flows of viscoelastic fluids: the role of uncertainty 
Abstract: In this talk a system theoretic approach is used to model and analyze the early stages of transition in inertialess channel flows of viscoelastic fluids. We argue that modeling of uncertainty, such as the approximate nature of polymer constitutive equations, is central to understanding the dynamics of viscoelastic fluids. Robustness with respect to uncertainty is quantified by induced norms from spatiotemporal body forces to components of velocity and polymer stress fluctuations. This inputoutput approach has strong connections to the analysis of pseudospectra of linear operators in Hilbert space, and it exhibits the importance of streamwise elongated flow patterns in viscoelastic fluids. For streamwise independent fluctuations, we establish an explicit unfavorable scaling of the L2induced norms with the Weissenberg number. This suggests that small amount of modeling uncertainty can destabilize nominally stable dynamics and promote transition to elastic turbulence. We also demonstrate that small stability margins originate from the stretching of polymer stress fluctuations by a background shear and identify the spatial structure of the most amplified fluctuations. One of the main messages of this talk is that, at the level of velocity fluctuation dynamics, polymer stretching and the Weissenberg number in elasticitydominated flows of viscoelastic fluids effectively play the role of vortex tilting and the Reynolds number in inertiadominated flows of Newtonian fluids.  
Ron Kimmel (TechnionIsrael Institute of Technology)  Metric geometry in action: Nonrigid shape acquisition, processing and analysis 
Abstract: GromovHausdorff distance (d_{GH}) is a definition for the discrepancy between metric spaces. Until recently, it has been applied mainly in theoretical exploration of metric spaces in metric geometry, as well as in theoretical computer science, specifically, in the context of metric embedding of graphs. A couple of years ago it was introduced into the field of shape analysis by Memoli and Sapiro. In this talk we will explore the relation between the GromovHausdorff distance and multidimensional scaling (MDS), a classical approach for embedding a given metric space into one in which distances can be analytically computed. The obvious example for such a target embedding space in MDS is Euclidean. Alternatively, we could use the Generalized MDS (GMDS) as a building block in numerically approximating d_{GH}. This generalization deals with target spaces in which distances can be numerically approximated rather than evaluated analytically. The exposition of ideas in metric geometry and numerical optimization would be motivated through practical examples like 3D face recognition, texture mapping in computer graphics, defining and numerically exploring intrinsic symmetries and more. We will start from the actual acquisition process and also present a 3D color video camera we developed and demonstrate the potential of our computational tools on various applications.  
Pawel Konieczny (University of Minnesota)  Thorough analysis of the Oseen system in 2D exterior domains 
Abstract: We construct Lpestimates for the inhomogeneous stationary Oseen system studied in a two dimensional exterior domain with inhomogeneous slip boundary conditions. The main part of the talk is a presentation of results for the half space ℝ2_{+}, which are substantial for the exterior problem. Main tools are given by the Fourier analysis in order to obtain maximal regularity estimates. In addition, these optimal estimates show us a difference between points on the boundary in front of the obstacle and behind the obstacle. The former are typical for elliptic problems while the latter show disturbance which is typical for parabolic problems.  
Andrew M. Kraynik (Sandia National Laboratories)  Foam structure and rheology: The shape and feel of random soap froth 
Abstract: Soap froth—the quintessential foam—is composed of polyhedral gas bubbles separated by thin liquid films. Why do foams have a shear modulus and yield stress, which we usually associate with solids? How are the bubbles shaped and how are they packed? These and other questions have been explored through simulations with the Surface Evolver, a computer program developed by Brakke. The calculations are in excellent agreement with seminal experiments by Matzke (1946) on the foam structure and shear modulus measurements by Princen and Kiss (1986). The connection between elasticplastic rheology and foam structure involves intermittent cascades of topological transitions; this cellneighbor switching is a fundamental mechanism of foam flow. The structure and rheology of wet foams, which have finite liquid content, will also be discussed.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DEAC0494AL85000. 

Satish Kumar (University of Minnesota)  Nonmodal amplification of disturbances in channel flows of viscoelastic fluids: A possible route to elastic turbulence? 
Abstract: This talk will provide an overview of our recent work on amplification of disturbances in channel flows of viscoelastic fluids. Even if a standard linear stability (i.e., modal) analysis predicts that a particular flow is stable, the question of the sensitivity of the flow to various disturbances remains. If disturbances to the linearized governing equations are sufficiently amplified over a finite time interval, then nonlinearities may become important and cause transition to a more complex flow state. This can happen if the underlying linear operator is nonnormal, and represents a nonmodal mechanism of disturbance amplification. We address this issue by adopting an inputoutput point of view borrowed from the systems and controltheory communities. The inputs to the linearized equations consist of spatially distributed and temporally varying body forces that are harmonic in the streamwise and spanwise directions and stochastic in the wallnormal direction and in time. Such inputs enable the use of powerful tools from linear systems theory that have recently been applied to analyze Newtonian fluid flows. We find that the most amplified disturbances are threedimensional in nature, and that large amplification can occur under conditions of weak inertia and strong elasticity. The underlying physical mechanism involves polymer stretching that introduces an effective liftup of flow fluctuations similar to vortextilting in inertiadominated flows. The mechanism examined here provides a possible route for a bypass transition to elastic turbulence and might be exploited to enhance mixing in microfluidic devices. (Joint work with Mihailo Jovanovic, University of Minnesota.)  
Tony Ladd (University of Florida)  LatticeBoltzmann methods for polymer solutions  A comparison with Brownian dynamics 
Abstract: I will outline the application of the fluctuating latticeBoltzmann equation to the simulation of polymer solutions. Then I will describe a numerical assessment of the accuracy of latticeBoltzmann methods for polymers, by comparison with Brownian dynamics simulations on a similar model system. We will examine the relaxation spectrum of an isolated chain and the migration of individual chains in shear and pressuredriven flows.  
Claude Le Bris (CERMICS)  The role of free energy in the mathematical and numerical analysis of complex fluids models 
Abstract: The talk will overview three recent works that make use of the notion of free energy to establish mathematical properties of some complex fluid models. The first work (in collaboration with B. Jourdain, T. Lelievre and F. Otto) studies the longtime behaviour of the solution to some multiscale models. The second work (by D. Hu and T. Lelievre) introduces a notion of free energy for purely macroscopic models. The third work (by S. Boyaval, T. Lelievre and C. Mangoubi) makes uses of the free energy to derive better numerical approaches.  
Triet Minh Le (Yale University)  Local scales in oscillatory patterns and boundaries of objects 
Abstract: In this talk, we study the problem of extracting local scales of oscillatory patterns in images and on plane curves. In the first case, Given a multiscale representation {u(t)} of an image f, we are interested in automatically picking out a few choices of t_{_}i(x), which we call local scales, that better represent the multiscale structure of f at x. We will characterize local scales coming from the Gaussian kernel. In the second case, we propose an approach to extracting local scales on curves to segment objects with irregular boundaries. Theory and experimental results will be presented with applications to image decomposition/denoising.  
Yann LeCun (New York University)  Learning feature hierarchies with sparse coding 
Abstract: Keywords: unsupervised learning, object recognition, sparse coding, convolutional networks Abstract:Image processing and recognition has traditionally relied on hardwired features and trainable classifiers. The next challenge of computer vision, machine learning, and image processing, is to devise methods that can automatically learn feature extractors and highlevel image representations from labeled and unlabeled data. The set of methods collectively known as "Deep Learning" is an attempt to learn hierarchies of features with multiple levels of abstraction, and suitable invariances. I will describe several deep learning methods, some of which involve new forms of sparse coding. Specific model architectures for image recognition, based on stacks on nonlinear filter banks, and trained with these methods will be described. A number of applications to object dectection, object recognition, and visionbased navigation for mobile robots will be shown.  
Yi Ma (University of Illinois at UrbanaChampaign)  Robust principal component analysis: Exact recovery of corrupted lowrank matrices via convex optimization 
Abstract: Principal component analysis is a fundamental operation in computational data analysis, with myriad applications ranging from web search, to bioinformatics, to dynamical system identification, to computer vision and image analysis. However, its performance and applicability in real scenarios are limited by a lack of robustness to outlying or corrupted observations. In this work, we consider the idealized “robust principal component analysis” problem of recovering a lowrank matrix A from corrupted observations D = A + E. Here, the error entries E can be arbitrarily large (modeling grossly corrupted observations common in visual and bioinformatic data), but are assumed to be sparse. We prove that most matrices A can be efficiently and exactly recovered from most error signandsupport patterns, by solving a simple convex program. Our result holds even when the rank of A grows nearly proportionally (up to a logarithmic factor) to the dimensionality of the observation space and the number of errors E grows in proportion to the total number of entries in the matrix. A byproduct of our analysis is the first proportional growth results for the related but somewhat easier problem of completing a lowrank matrix from a small fraction of its entries. We propose a provably convergent algorithm based on proximal gradient and iterative thresholding that, for large matrices, is significantly faster and more scalable than generalpurpose solvers. We provide simulations and realdata examples corroborating the theoretical results. The simulation results actually have revealed even more striking phenomena and remarkable pictures that merit future investigation.
This is joint work with my students John Wright, Arvind Ganesh, and Shankar Rao.
Brief Biography: Yi Ma is an associate professor at the Electrical & Computer Engineering Department of the University of Illinois at UrbanaChampaign. He is currently on leave as research manager of the Visual Computing group at Microsoft Research Asia in Beijing. His research interests include computer vision, image processing, and systems theory. Yi Ma received two Bachelors’ degree in Automation and Applied Mathematics from Tsinghua University (Beijing, China) in 1995, a Master of Science degree in EECS in 1997, a Master of Arts degree in Mathematics in 2000, and a PhD degree in EECS in 2000, all from the University of California at Berkeley. Yi Ma received the David Marr Best Paper Prize at the International Conference on Computer Vision 1999 and the LonguetHiggins Best Paper Prize at the European Conference on Computer Vision 2004. He also received the CAREER Award from the National Science Foundation in 2004 and the Young Investigator Award from the Office of Naval Research in 2005. He has given several Plenary Talks at international conferences. He is an associate editor of IEEE Transactions on Pattern Analysis and Machine Intelligence. He is a senior member of IEEE and a member of ACM, SIAM, and ASEE. 

Christopher Macosko (University of Minnesota)  Teaching rheology using product design 
Abstract: The poster describes two courses on experimental rheology offered over the past several years to seniors and first year graduate students at our institutions (KU Leuven Belgium and U of Minnesota). These laboratory courses use complex materials available from the shelves of our local retailers. We have found that measuring the rheology of face cream, shampoo, paint, chewing gum or plastic bags provides great motivation for students to learn rheology fundamentals.  
Kara Lee Maki (University of Minnesota)  Human tear film dynamics on an eyeshaped domain 
Abstract: We present recent progress in understanding the dynamics of human tear film on an eyeshaped domain. Using lubrication theory, we model the evolution of the tear film over a blink cycle. The highly nonlinear governing equation is solved on an overset grid by a method of lines coupled with finite difference in the Overture framework. Comparisons with experimental observations show qualitative agreement.  
Mario Micheli (University of California, Los Angeles)  Sectional curvature of the Riemannian manifold of landmarks 
Abstract: Keywords: Shape spaces, landmark points, sectional curvature Abstract: In the past few years there has been a growing interest, in diverse scientific communities, in endowing "shape spaces" with Riemannian metrics, so to be able to measure similarities between shapes and perform statistical analysis on data sets (e.g. for object recognition, target detection and tracking, classification, and automated medical diagnostics). The geometry of such spaces has started to emerge only very recently; in this talk we will explore the sectional curvature for the Riemannian manifold of landmark points (which is one of the simplest, in that it is finitedimensional) and discuss its effects on applications.  
Sorin Mitran (University of North Carolina)  Continuummicroscopic computational modeling of nonequilibrium viscoelastic flow 
Abstract: The problem of coupling microscopic and continuumlevel descriptions of complex fluids when the microscopic system exhibits slow relaxation times is considered. This type of problem arises whenever the fluid exhibits significant memory effects. The main difficulty in this type of multiscale computation is the initialization of microscopic configurations and establishing the duration of microscopic evolution that has to be computed before a continuum time step can be taken. Density estimation theory is applied to determine the distribution of random variables characterizing the microscopic system. Additional mesoscale equations for the probability density functions required to characterize microscopic states are determined from successive bursts of microscopic simulation. The time evolution of the mesoscale equations is computed using highorder AdamsBashforthMoulton predictorcorrector algorithms. The overall computational model is exemplified on a RoliePoly fluid. The main benefit of the approach considered here is that the complication of deriving an algorithm for complicated constitutive laws is sidestepped without the need for prohibitively expensive computation at the microscale.  
JeanMichel Morel (École Normale Supérieure de Cachan)  Online image processing 
Abstract: Keywords: Online image processing, unsupervised algorithms, fast algorithms, color balance, screened Poisson equation, denoising, image comparison, Retinex theory, affine invariant SIFT Abstract: This is a new concept of publication for image processing. Putting image processing and image analysis algorithms on line allows every researcher to test directly the algorithms on his (her) own images. Some sample images are also proposed on each algorithm site. This project is under construction, but several algorithms are already available at http://mw.cmla.enscachan.fr/megawave/algo/. Each on line algorithm is described in a web site, which gives the main bibliographic links, and which comments on many experimental results. Each algorithm is also thoroughly described, and a code can be downloaded. Image processing on line is only possible with algorithms which have been mathematically analyzed and rationalized to the point where they do not depend anymore on technical parameters. A publication on line is different from but can be complementary to a journal publication. The online algorithms must be elaborated to the point where they are fully autonomous, or depend on at most one user's parameter (typically the scale). I'll describe briefly the online algorithms: Microtexture synthesis algorithm, a Cartoon + Texture decomposition, a fully autonomous line segment detector, a PDE implementation of the color perception Retinex theory or a fully affine invariant image comparison algorithm, ASIFT.  
Jeffrey F. Morris (City College, CUNY)  Particle pressureinduced phenomena in suspensions: from osmosis to granular dilation 
Abstract: The coupling of microstructure to bulk flow behavior is a hallmark of nonNewtonian flows in general. When the nonNewtonian fluid is a twophase material where the dispersed and continuous phases may readily segregate, this coupling is found to result in quite striking migration of particles and fluid, with significant impact on the flow structure as a consequence. In this talk, we first describe a general approach to understanding the migration phenomena based on particle pressure, the nonequilibrium continuation of osmotic pressure to sheared dispersions of solids (here in Newtonian liquids only), considering the microstructural origins of the behavior, its the macroscopic consequences, and how particle pressure may be measured. This will be followed by a consideration of the flow through a channel contraction of a very concentrated suspension – near and at the jamming limit of about up to 58% solids for the system studied experimentally, so that hydrodynamic and contact forces both play a role. In the contraction geometry, the effluent generally has a lower solid fraction than the upstream suspension, a phenomenon known as selffiltration, and we will show that selffiltration may be described by a mechanism where liquid flow is driven by variation of the particle pressure within the geometry.  
Susan J. Muller (University of California, Berkeley)  Effects of elasticity on high Reynolds number instabilities in TaylorCouette flow 
Abstract: Keywords: Elasticity, viscoelastic instability, nonlinear transitions, dragreducing polymers Abstract: TaylorCouette flow (i.e., flow between concentric, rotating cylinders) has long served as a paradigm for studies of hydrodynamic stability. For Newtonian fluids, the rich cascade of transitions from laminar, Couette flow to turbulent flow occurs through a set of wellcharacterized flow states that depend on the Reynolds numbers of both the inner and outer cylinders (Re_{i} and Re_{o}). While extensive work has been done on (a) the effects of weak viscoelasticity on the first few transitions for Re_{o} = 0 and (b) the effects of strong viscoelasticity in the limit of vanishing inertia (Re_{i} and Re_{o} both vanishing), the viscoelastic TaylorCouette problem presents an enormous parameter space, much of which remains completely unexplored. Here we describe our recent experimental efforts to examine the effects of drag reducing polymers on the complete range of flow states observed in the TaylorCouette problem. Of particular importance in the present work is 1) the rheological characterization of the test solutions via both shear and extensional (CaBER) rheometry, 2) the wide range of parameters examined, including Re_{i}, Re_{o}, and Elasticity number El, and 3) the use of a consistent, conservative protocol for accessing flow states. We hope to gain insights into the roles of weak elasticity and of co and counterrotation on nonlinear transitions in this flow.  
Facundo Mémoli (Stanford University)  Some recent developments in the use of GromovHausdorff and GromovWasserstein metrics 
Abstract: Keywords: GromovHausdorff distance, GromovWasserstein distance, shape analysis, metric geometry Abstract: The GromovHausdorff distance provides a powerful tool for formalizing the problem of shape matching. Two problems with it are that (1) in practice it leads to combinatorial optimization problems which are NP hard and (2) despite its theoretical attractiveness and naturality, it has been difficult to use for studying and establishing links to the many other shape matching methods available in the literature. The GromovWasserstein distance, a variant of the GromovHausdorff distance that is based on mass transportation ideas, directly leads to continuous optimization problems with quadratic objective functions and linear constraints. Furthermore, it has been proved that the methods based on shape distributions, shape context/integral invariants, and eccentricity can all be related to this GromovWasserstein distance via explicit lower bounds. In this talk we review the construction of the GW distance, its properties and lower bounds. In particular, we describe recent work done on (1) relating it to persistent topology based shape signatures, and (2) on defining a certain spectral notion of the GW distance. This spectral notion of the GW distance permits proving that several invariants constructed from the spectrum of the LaplaceBeltrami operator on manifolds are stable in a quantitative way.  
Cecilia OrtizDuenas (University of Minnesota)  Identifying, characterizing and modeling coherent structures of turbulent boundary layers 
Abstract: Coherent structures, i.e. hairpin vortices, which align in groups or packets, were proposed as a fundamental structure of turbulent boundary layers more than 50 years ago in the literature. Although the existence of these structures and packets has been demonstrated, their generation, development, and interaction is not yet understood. Recently, planar and volumetric velocity measurements obtained by PIV provide direct information on spatial velocity variations as well as timeaveraged statistics from which the characteristics of individual and of statistical ensembles of structures can be obtained. It is proposed here to integrate these experimental results into numerical models, such as the attached eddy model as described by Perry and Marusic (1995), to further the understanding of these structures under various conditions. The challenges in identifying, characterizing and modeling these coherent structures will be discussed.  
Matteo Pasquali (Rice University)  Computing complex flows of complex fluids 
Abstract: Flows with free surfaces and free boundaries arise in many industrial and biological applications. Examples are coating, polymer processing, inkjet printing, DNA arrays, spraying, deformation of blood cells, blood flow in arteries and capillaries, and flow in the deep pulmonary alveoli. Most of these flows have two distinguishing features: (1) the fluid is complex (microstructured ); thus, the stress includes a viscoelastic term which is important and sometimes dominant, and (2) the surface forces are comparable to the viscous and elastic ones. Inertia is usually immaterial in these flows, because the relevant length scales are well below a millimeter. The surface and viscoelastic forces give rise to large nondiagonal contributions in the momentum equation. Other nondiagonal terms come from the coupling of the shape of the free boundaries to the velocity field, and strong dependence of the microstructure evolution on the velocity gradient. Thus, fullycoupled algorithms for solving the steady as well as timedependent equations of the flow are desirable. I will discuss developments in applying mesoscopic models of microstructured liquids to threedimensional free surface flows. In such models, the liquid microstructure is captured by tensors obeying convectiondiffusiongeneration equations—e.g., the gyration tensor of ensembles of polymer molecules, or the shape tensor of droplets or blood cells. Mesoscopic nonequilibrium thermodynamics ties the elastic stress to velocitygradientdependent terms in the microstructure evolution. This dependence yields general theories accounting for disparate microstructural models that are compatible with macroscopic transport phenomena and thermodynamics. Such theories can be incorporated into general threedimensional finite element codes based on fully coupled formulations. Combining Newton’s method with GMRES and a Sparse Approximate Inverse Preconditioner yields a robust and efficient method for computing threedimensional flows on lowcost parallel clusters. I will show results on model flows of polymer solutions, and discuss developments and connections to finegrain, microscopic models of complex fluids where microstructure is tracked by using stochastic differential equations.  
Ronald Phillips (University of California, Davis)  Structural instability in sedimentation through viscoelastic fluids 
Abstract: A theory has been developed to describe a structural instability that is observed during the sedimentation of particulate suspensions through viscoelastic fluids. The theory is based on the assumption that the influence of hydrodynamic interactions in viscoelastic fluids, which tend to cause particles to aggregate, is in competition with hydrodynamic dispersion, which acts to maintain a homogeneous microstructure. In keeping with the experimental observations, it predicts that the suspension structure will stratify into vertical columns when a dimensionless stability parameter exceeds a critical value. The columntocolumn separation, measured in particle radii, is predicted to be proportional to the square root of the ratio of the dimensionless dispersion coefficient to the product of the particle volume fraction and the Deborah number. The time for the formation of the columns is predicted to scale with the inverse of the average volume fraction. These predictions are in agreement with experimental data reported in the literature.  
Tim Phillips (Cardiff University)  Spherical bubble collapse in viscoelastic fluids 
Abstract: The collapse of a spherical bubble in an infinite expanse of viscoelastic fluid is considered. For a range of viscoelastic models, the problem is formulated in terms of a generalized Bernoulli equation for a velocity potential, under the assumptions of incompressibility and irrotationality. The boundary element method is used to determine the velocity potential and viscoelastic effects are incorporated into the model through the normal stress balance across the surface of the bubble. In the case of the Maxwell constitutive equation, the model predicts phenomena such as the damped oscillation of the bubble radius in time, the almost elastic oscillations in the large Deborah number limit and the rebound limit at large values of the Deborah number. A rebound condition in terms of $ReDe$ is derived theoretically for the Maxwell model by solving the RayleighPlesset equation. A range of other viscoelastic models such as the Jeffreys model, the Rouse model and the DoiEdwards model are amenable to solution using the same technique. Increasing the solvent viscosity in the Jeffreys model is shown to lead to increasingly damped oscillations of the bubble radius.  
Todd Plantenga (Sandia National Laboratories)  Optimization algorithms for applications in industry 
Abstract: The talk will describe the speaker's experience in designing and implementing optimization algorithms for applications in industry. Discussion will focus on a retail price optimization algorithm that uses stochastic methods to handle uncertainties. The project started with a textbook approach (stochastic optimization with recourse) and evolved into a special purpose solution suited to the business case. The speaker was directly involved in gathering requirements, prototyping a mathematical model and algorithmic approach, investigating issues with real world data, and writing production software for the final implementation. The completed project currently recommends optimal prices on over 10,000 items per day. Dr. Plantenga obtained a PhD from Northwestern University in 1994 studying largescale nonlinear optimization methods. He has developed optimization software for PeopleSoft/Oracle, Gap Inc, Ziena Optimization, and his current employer, Sandia National Laboratories.  
Harald Pleiner (Max Planck Institute for Polymer Research)  The generalized hydrodynamic theory  transient elasticity and other examples 
Abstract: For modeling complex fluids (and more generally soft matter) on the phenomenological level a generalization of the wellknown hydrodynamic method is proposed. It preserves the basic thermodynamic rules and linear response structure of ordinary hydrodynamics, but allows the handling of additional mesoscopic degrees of freedom that make those materials 'complex'. This is exemplified by discussing transient elasticity and applying it explicitly to the nonNewtonian behavior of polymers (and colloidal systems). Transient elasticity seems to be the defining physics for those systems and also for yield stress soft matter. As a second example true 2fluid systems and the problems of their generalized hydrodynamics are briefly described.  
Rob Poole (University of Liverpool)  Purelyelastic instabilities in extensional flows 
Abstract: Using a finitevolume numerical technique we demonstrate that viscoelastic flow in a range of symmetric geometries  with symmetric inlet flow conditions  containing a region of strong extensional flow goes through a bifurcation to a steady asymmetric state. We show that this asymmetry is purely elastic in nature and that the effect of inertia is a stabilizing one. Our results in one such geometry  the so called “crossslot”  are in excellent qualitative agreement with recent experimental visualizations of a similar flow in a microfluidic apparatus [Arratia et al. Phys. Rev. Lett., 2006 96(14)]. We investigate effects of constitutive equation (UCM, OldroydB, PTT and FENECR models), model parameters and effects due to three dimensionality.  
Weiqing Ren (New York University)  A seamless algorithm for multiscale simulations 
Abstract: I will present a seamless algorithm for the study of multiscale problems. The multiscale method aims at capturing the macroscale behavior of a given system which is modeled by an (incomplete) macroscale model. This is done by coupling the macro model with a micro model: The macro model provides the necessary constraint for the micro model and the micro model supplies the missing data (e.g. the constitutive relation or the boundary conditions) needed in the macro model. In the multiscale method, the macro and micro models evolve simultaneously using different time steps, and they exchange data at every step. The micro model uses its own appropriate (micro) time step. The macro model uses a macro time step but runs at a slower pace than required by accuracy and stability considerations in order for the micro dynamics to have sufficient time to adapt to the environment provided by the macro state. The method has the advantage that it does not require the reinitialization of the micro model at each macro time step or each macro iteration step. The data computed from the micro model is implicitly averaged over time.  
Michael Renardy (Virginia Polytechnic Institute and State University)  Mathematical issues in stability of viscoelastic flows 
Abstract: "Traditional" hydrodynamic stability studies infer stability of a flow from a computation of eigenvalues of the linearized system. While this is well justified for the NavierStokes equations, no rigorous result along these lines is known for general systems of partial differential equations; indeed there are counterexamples for lower order perturbations of the wave equations. This lecture will discuss how recent results on "advective" equations can be applied to creeping flows of viscoelastic fluids of Maxwell or Oldroyd type. For spatially periodic flows, stability can be reduced to the study of a) the eigenvalues, and b) a system of nonautonomous ordinary differential equations that arises from a geometric optics approximation for short waves. A more complete result for the upper convected Maxwell model will also be discussed.  
Yuriko Renardy (Virginia Polytechnic Institute and State University)  The response of a hydrophobic superparamagnetic ferrofluid droplet suspended in a viscous fluid in a uniform magnetic field: the influence of microstructure on interfacial tension 
Abstract: The microstructure of a ferrofluid influences its motion under applied magnetic fields. A ferrofluid typically consists of magnetite nanoparticles suspended in a solvent. Here, we consider a ferrofluid that has no solvent, with the advantage that the particles do not migrate under externally applied magnetic fields, and therefore the physical properties of the ferrofluid can be more easily characterized. The deformation of a biocompatible hydrophobic ferrofluid drop suspended in a viscous medium is investigated numerically and compared with experimental data. At high magnetic fields, experimental drop shapes deviate from numerical results when a constant surface tension value is used. One hypothesis for the difference is the dependence of interfacial tension on the magnetic field in the experimental data. This idea is investigated with direct numerical simulations.  
Yuriko Renardy (Virginia Polytechnic Institute and State University)  Numerical investigation of drop deformation in shear 
Abstract: No Abstract  
Jonathan P. Rothstein (University of Massachusetts)  The dynamics and stability of viscoelastic wormlike micelle solutions in strong extensional flows 
Abstract: Under the proper conditions, surfactant molecules can selfassemble into wormlike micelles, resembling slender rods, can entangle and impart viscoelasticity to the fluid. The behavior of wormlike micelles solutions is similar to that of polymer solutions. The primary difference being that, unlike covalently bound polymers, micelles are continuously breaking and reforming under Brownian fluctuations and the imposed shear or extensional flow field. In this talk, we will discuss the behavior of a series of viscoelastic wormlike micelle solutions in extensional flows and describe several newly observed instabilities and flow phenomena unique to these fluids. In the first part of the talk, we will describe the behavior of these fluids in the homogeneous uniaxial extensional flow produced by a filament stretching rheometer. Like polymer solutions, wormlike micelle solutions demonstrate significant strain hardening and a failure of the stressoptical. At a critical stress, the wormlike micelle solutions filaments were found to fail through a dramatic rupture near the axial midplane. This filament failure likely stems from the local scission of individual wormlike micelle chains. We will discuss the effect that preconditioning can have on the response of these materials and demonstrate that the presence of branching in wormlike micelle solutions can significant reduce the strain hardening of the extensional viscosity. In the second part of the talk, we will describe how the extensional rheology of these wormlike micelle solutions can affect more complex flows by presenting a series of interesting new flow phenomena unique to wormlike micelle solutions. The experiments will include the observation of a new instability in the flow past a falling sphere, through a periodic array of cylinders and past a single cylinder. The flows are investigated through a variety of experimental techniques including the use of high speed imaging, particle image velocimetry and flow induced birefringence measurements.  
Guillermo R. Sapiro (University of Minnesota)  A fast view of real life video segmentation and a slower view of learning dictionaries for efficient representations 
Abstract: After spending about 5 minutes showing recent results on video segmentation (joint work with Adobe), I will describe some recent works in my group in the area of dictionary learning and sparse coding. In particular I will present new models derived from information theory, new models dedicated to go beyond standard sparse coding applications and into unsupervised clustering, and new models related to compressed sensing.  
Eric S. G. Shaqfeh (Stanford University)  Dynamics of flowing polymer solutions I 
Abstract: No Abstract  
Eric S. G. Shaqfeh (Stanford University)  Dynamics of flowing polymer solutions II 
Abstract: No Abstract  
Michael J. Shelley (New York University)  Mixing and instability in two complex fluid flows 
Abstract: Keywords: Mixing, Instability, Complex Fluids Abstract: I will discuss two problems where flow instability drives a complex fluid  or at least its mathematical model  into intrinsic oscillations and unsteadiness. Both are in the Stokesian regiime where inertial effects are negligible. In the first, a viscoelastic fluid described by the OldroydB model is driven by a background force that creates a local extensional flow. Beyond a critical Weissenberg number, stress accumulates rapidly there, and a symmetry breaking instability leads to coherent structures and multiple frequencies of oscillation. In the second, the complex fluid is a selfdriven suspension of active swimmers. Analysis and simulation show the existence of longwave instabilities that drive the system from isotropy to strongly mixing flows with systemsize correlations.  
Ali Shokoufandeh (Drexel University)  Selection of canonical subsets using nonlinear optimization 
Abstract: Keywords: Feature Selection, Canonical Elements, Object Recognition, and Reconstruction Abstract: The problem of representing a large dataset consisiting of complex patterns with a smaller more compact form has been tackled through synthesis of new data points to represent clusters of the original data points (feature transformation). In contrast, the focus of this research is on the development of a generic methods for selecting canonical subsets of datasets that are highly representative of the original complex patterns. The development of the canonical subset method was motivated by the fact that in many cases feature transformation may not be practical, relevant, or even possible. Our objective is to expose the underlying structure of the data and have the global topology drive the subsetselection process. The contributions of the work are formulation of the subset selection problem as an optimization problem, an analysis of the complexity of the problem, the development of approximation algorithms to compute canonical subsets, and a demonstration of the utility of the algorithms in several problem domains.  
Michael S. Siegel (New Jersey Institute of Technology)  Efficient numerical computation of fluid interfaces with soluble surfactant: a viscous drop 
Abstract: We address a significant difficulty in the numerical computation of fluid interfaces with soluble surfactant. At large values of bulk Peclet number for representative fluidsurfactant systems, a transition layer forms adjacent to the interface in which the surfactant concentration varies rapidly. Accurate calculation of the concentration gradient at the interface is essential to determine bulkinterface exchange of surfactant and the drop's dynamics. We present a fast and accurate `hybrid' numerical method that incorporates a separate singular perturbation reduction of the transition layer into a full numerical solution of the interfacial free boundary problem. Results are presented for a drop of arbitrary viscosity in the Stokes flow limit, where the underlying flow solver for insoluble surfactant uses a direct (primitive variable) boundary integral method.  
Linda B. Smolka (Bucknell University)  Planar extensional motion of an inertiallydriven liquid sheet 
Abstract: We derive a timedependent exact solution of the free surface problem for the NavierStokes equations that describes the planar extensional motion of a viscous sheet driven by inertia. The linear stability of the exact solution to one and twodimensional symmetric perturbations is examined in the inviscid and viscous limits within the framework of the longwave or slender body approximation. Both transient growth and longtime asymptotic stability are considered. For onedimensional perturbations in the axial direction, viscous and inviscid sheets are asymptotically marginally stable, though depending on the Reynolds and Weber numbers transient growth can have an important effect. For onedimensional perturbations in the transverse direction, inviscid sheets are asymptotically unstable to perturbations of all wavelengths. For twodimensional perturbations, inviscid sheets are unstable to perturbations of all wavelengths with the transient dynamics controlled by axial perturbations and the longtime dynamics controlled by transverse perturbations. The asymptotic stability of viscous sheets to onedimensional transverse perturbations and to twodimensional perturbations depends on the capillary number (Ca); in both cases, the sheet is unstable to longwave transverse perturbations for any finite Ca. This work is in collaboration with Thomas P. Witelski.  
Radhakrishna Sureshkumar (Washington University)  Nonlinear pattern formation and coherent structure dynamics in viscoelastic Flows 
Abstract: Ability to manipulate equilibrium selfassembly and dynamical selforganization in nonlinear systems is of central importance to the success of many emerging technologies. This seminar will focus on flow instability and pattern formation in complex fluids, i.e., fluids with internal microstructure such as solutions/melts of polymers, surfactant/colloidal gels and suspensions. Specific examples discussed will include coherence and chaos in turbulent flows of “viscoelastic” dilute polymer solutions (PRL, 100, 134504 (2008)), solitary vortex solutions that manifest as a result of elastic stressmediated self organization in complex fluids (PRL, 97, 054501 (2006)) and purely flowinduced phase transitions in surfactant micelles (J. Rheol. . 52, 52750 (2008)).  
Radhakrishna Sureshkumar (Washington University)  Hydrodynamic pattern formation in ultrathin metal films: Robust route to plasmonic nanomaterials 
Abstract: Sustainable production, storage and transportation of renewable energy is one of the greatest challenges of the 21st century. Harnessing Sun's energy for powering our planet has long been a dream of scientists and engineers. Despite the universal appeal and growing usage of solar energy systems across the globe, notably in developing economies, the efficiency of energy conversion has remained well below desirable levels for commercial installations. This is especially a major concern for new generation photovoltaics, which utilize a thin film (~ 1 micron thick) of the photoactive material. In this case, traditional light trapping techniques such as optical gratings (~ several microns) employed for cells based on bulk photoconductors are not applicable. Metallic nanocomposites offer much promise in efficient and costeffective solar energy harvesting especially for thin film photocells. The central idea is to exploit the plasmonic interaction between electromagnetic waves and the localized oscillations of the free electron gas density at the nanoparticledielectric interface. From a renewable energy perspective, plasmonics principles can be used to tailor the spectral response of a material to fit applications such as broadband solar absorption and photobioreactor design. This is accomplished by manipulating the particle size, aspect ratio and volume fraction as well as utilizing hybridization techniques (e.g. coreshell materials, multimetal composites). In this talk, a robust manufacturing route for such materials, namely laserinduced melting, dewetting and selforganization of ultrathin (~ nm) metal films deposited on a suitable substrate, will be discussed [APL 91, 043105 (2007); Phys. Rev. B, 75, 235439 (2007); Nanotechnology, 17, 4229 (2006); Phys. Rev. Lett., 101, 017802 (2008)]. Specifically, it will be shown that the knowledge of thin film hydrodynamic instabilities can be utilized to predict nanoparticle size and spacing observed in such experiments. The mechanisms of pattern formation will be illustrated using experimental visualizations of the dewetting process.  
Vladimir Sverak (University of Minnesota)  Topics in the theory of the NavierStokes equations 
Abstract: The course will cover certain selected topics in the theory of the NavierStokes equations. After a brief overview of the main issues of the general theory we will focus on problems in the theory of the steadystate solutions. There are many open problems concerning the steadystate solutions. These problems are presumably easier than the main open questions about the timedependent equations. Nevertheless, some of them have remained unsolved since their first explicit formulation in the pioneering works of Jean Leray in the 1930s. There is a certain indirect similarity (or "duality") between the mathematical issues raised by these steadystate problems and the issues which come up in connection with the more wellknown open problems about the timedependent equations. In the lectures I hope to cover some of the important results about the steadystate solutions and discuss some of the open problems. The course will be accessible to postdocs and to graduate students with some knowledge of PDEs. For example, an introductory graduate PDE course should be a sufficient prerequisite.  
Vladimir Sverak (University of Minnesota)  Topics in the theory of the NavierStokes equations 
Abstract: The course will cover certain selected topics in the theory of the NavierStokes equations. After a brief overview of the main issues of the general theory we will focus on problems in the theory of the steadystate solutions. There are many open problems concerning the steadystate solutions. These problems are presumably easier than the main open questions about the timedependent equations. Nevertheless, some of them have remained unsolved since their first explicit formulation in the pioneering works of Jean Leray in the 1930s. There is a certain indirect similarity (or "duality") between the mathematical issues raised by these steadystate problems and the issues which come up in connection with the more wellknown open problems about the timedependent equations. In the lectures I hope to cover some of the important results about the steadystate solutions and discuss some of the open problems. The course will be accessible to postdocs and to graduate students with some knowledge of PDEs. For example, an introductory graduate PDE course should be a sufficient prerequisite.  
Vladimir Sverak (University of Minnesota)  Topics in the theory of the NavierStokes equations 
Abstract: The course will cover certain selected topics in the theory of the NavierStokes equations. After a brief overview of the main issues of the general theory we will focus on problems in the theory of the steadystate solutions. There are many open problems concerning the steadystate solutions. These problems are presumably easier than the main open questions about the timedependent equations. Nevertheless, some of them have remained unsolved since their first explicit formulation in the pioneering works of Jean Leray in the 1930s. There is a certain indirect similarity (or "duality") between the mathematical issues raised by these steadystate problems and the issues which come up in connection with the more wellknown open problems about the timedependent equations. In the lectures I hope to cover some of the important results about the steadystate solutions and discuss some of the open problems. The course will be accessible to postdocs and to graduate students with some knowledge of PDEs. For example, an introductory graduate PDE course should be a sufficient prerequisite.  
Vladimir Sverak (University of Minnesota)  Topics in the theory of the NavierStokes equations 
Abstract: The course will cover certain selected topics in the theory of the NavierStokes equations. After a brief overview of the main issues of the general theory we will focus on problems in the theory of the steadystate solutions. There are many open problems concerning the steadystate solutions. These problems are presumably easier than the main open questions about the timedependent equations. Nevertheless, some of them have remained unsolved since their first explicit formulation in the pioneering works of Jean Leray in the 1930s. There is a certain indirect similarity (or "duality") between the mathematical issues raised by these steadystate problems and the issues which come up in connection with the more wellknown open problems about the timedependent equations. In the lectures I hope to cover some of the important results about the steadystate solutions and discuss some of the open problems. The course will be accessible to postdocs and to graduate students with some knowledge of PDEs. For example, an introductory graduate PDE course should be a sufficient prerequisite.  
Karel Tuma (Charles University in Prague)  A thermodynamically compatible rate type fluid to describe the response of asphalt 
Abstract: We consider a class of viscoelastic rate type models that in particular includes: (i) OldroydB fluid model with three parameters, (ii) nonlinear fluid model derived Rajagopal and Srinivasa [2000] with three parameters, and (iii) nonlinear model with five parameters. We are interested in observing how well are these models capable to capture the experimental data for asphalt performed by J. Murali Krishnan, Indian Institute of Technology, Madras using dynamic shear rheometer. We find out that the model (i) is not able to capture the experimentally observed overshoot for the torque, while we obtain overshoots for the models (ii) and (iii).  
Alan VanNevel (Naval Air Warfare Center)  Government/DoD/Navy talk: Navy needs Automated image understanding 
Abstract: No Abstract  
René Vidal (Johns Hopkins University)  Sparse subspace clustering 
Abstract: We propose a method based on sparse representation to cluster data drawn from multiple lowdimensional linear or affine subspaces embedded in a highdimensional space. Our method is based on the fact that each point in a union of subspaces has a sparse representation with respect to a dictionary formed by all other data points. In general, finding such a spare representation is NP hard. Our key contribution is to show that, under mild assumptions, the sparse representation can be obtained 'exactly' by using _{1} optimization. The segmentation of the data is obtained by applying spectral clustering to a similarity matrix built from this sparse representation. Our method can be extended to handle noise, outliers as well as missing data by exploiting sparsity. Experiments on the Hopkins155 motion segmentation database and other motion sequences with outliers and missing data show that our approach significantly outperforms stateoftheart methods.  
Petia M. Vlahovska (Dartmouth College)  Complex motions of vesicles and red blood cells in flow 
Abstract: Blood flow in the microcirculation is an extensively studied problem, yet the behavior of red blood cells (RBCs) continues to surprise researchers. For example, recently it was discovered that in steady shear flow RBCs not only tanktread or tumble, but can also "swing" (tanktreading accompanied by oscillations in the inclination angle) [Abkarian et al. PRL 2007]. I will present our analytical work that quantitatively explains this behavior and other features in the RBCs dynamics. In steady shear flows, the theory shows that a closed lipid membrane (vesicle or RBC) deforms into a prolate ellipsoid, which tumbles at low shear rates, and swings at higher shear rates. The amplitude of the oscillations decreases with shear rate. The viscosity of a dilute suspension of vesicles or RBCs exhibits a minimum at the tanktreading to tumbling transition. In quadratic flows, the theory predicts a peculiar coexistence of parachute and bulletlike vesicle shapes at the flow centerline. Vesicles and RBCs always migrate towards the flow centerline unlike drops, whose direction of migration depends on the viscosity ratio. In timedependent flows, vesicles can exhibit chaotic dynamics.  
Lynn M. Walker (Carnegie Mellon University)  Shear alignment and mechanical properties of nanostructured hydrogels 
Abstract: Keywords: Block copolymer solutions, hydrogels, shear aligned, soft crystals Abstract: Selfassembled block copolymer templates can be used to control the nanoscale structure of materials that would not otherwise order in solution. In this work, we have developed a technique to use closepacked cubic and cylindrical mesophases of a thermoreversible block copolymer (PEOPPOPEO) to impart spatial order on dispersed nanoparticles. The thermoreversible nature of the template allows for the dispersion of particles synthesized outside the template. This feature extends the applicability of this templating method to many particlepolymer systems and also permits a systematic evaluation of the impact of design parameters on the structure and mechanical properties of the nanocomposites. The criteria for forming cocrystals has been fully characterized using contrastmatching smallangle neutron scatting (SANS) and the mechanical properties of these soft crystals determined. SANS experiments also demonstrate that shear can be used to align the nanocomposites into singlecrystal macrodomains; the first demonstration of the formation of singlecrystal nanoparticle superlattices. We are currently utilizing SANS to understand the flow mechanisms of both the neat block copolymer solutions and several types of these cocrystals.  
Shawn W. Walker (New York University)  Shape optimization of peristaltic pumping 
Abstract: We present a variational method for optimizing peristaltic pumping in a two dimensional periodic channel with moving walls to pump fluid (peristalsis is common in biology). No a priori assumption is made on the wall motion, except that the shape is static in a moving wave frame. Thus, we pose an infinite dimensional optimization problem and solve it with finite elements. L^{2}type projections are used to compute quantities such as curvature and boundary stresses.  
Qi Wang (University of South Carolina)  Kinetic theories for complex fluids 
Abstract: Keywords: kinetic theory, polymerparticulate nanocomposites, biaxial liquid crystal polymers. Abstract: In this talk, I will discuss some latest development in the modeling of polymerparticulate nanocomposites (PNC) and biaxial liquid crystal polymers (BLCP) using kinetic theories. Kinetic theory formulation allows one to integrate the microscopic dynamics to the background macroscopic flow field to yield a twolevel or even multilevel model for various complex fluids. Equilibrium phases and dynamical states of the PNC and BLCP will be discussed and their rheological responses to shear investigated.  
Sijue Wu (University of Michigan)  Colloquium: Wellposedness of the full water wave problem in two and three dimensions 
Abstract:  
Laurent Younes (Johns Hopkins University)  Diffeomorphisms and active contours 
Abstract: Keywords: Shape evolution; Shape spaces; Active contours; Riemannian metrics on diffeomorphisms Abstract: We present a geometric flow approach to the segmentation of two three dimensional shapes by minimizing a cost function similar to the ones used with geometric active contours or to the ChanVese approach. Our goal, welladapted to many shape segmentation problems, including those arising from medical images, is to ensure that the evolving contour or surface remains smooth and diffeomorphic to its initial position over time. This is formulated as a variational problem in a group of diffeomorphisms equipped with a rightinvariant Riemannian metric. A resulting gradient descent algorithm is used, with an interesting variant that constrains the velocity in shape space to belong in a finite dimensional space determined by timedependent control points. Experimental results with 2D and 3D shapes will be presented.  
Arghir Dani Zarnescu (University of Oxford)  Validity and limitations of the statistical scaling hypothesis for a nematic liquid crystal flow 
Abstract: The transition from the isotropic into the nematic state occurs, in a thermotropic liquid crystals, through the creation of nematically ordered islands in the overall isotropic fluid. It was argued in the physics literature that the domain growth of the nematic state is a scaling phenomenon: the pattern of domains at a later time looks statistically similar to that at an earlier time, up to a timedependent change of scale. The statistical scaling hypothesis states that at a large enough time the equal time scalar correlation function C(r,t) will assume a scaling form f(r/L(t)) where L(t) is the timedependent length scale of nematic domains. The precise asymptotics of L(t) for large t have been the subject of a significant debate in the physics literature. We present a mathematically rigorous analysis of the equations that shows under what conditions the scaling hypothesis holds and what are the correct asymptotics of L(t) for large t. This is joint work with Eduard Kirr (University of Illinois at UrbanaChampaign).  
Weigang Zhong (University of Minnesota)  Modified immersed boundary modeling and simulation of concentrated suspensions 
Abstract: One major example of dense multiphase flows in engineering is the extrusion process which is a crucial part in the industrial production of ceramic products. I study the extrusion batch flow through multiscale modeling and a modified immersed boundary (IB) method with directforcing. A software package (IBAMR) with support for Cartesian grid adaptive mesh refinement developed by B. Griffith from New York University is utilized to implement the IB method. Preliminary numerical experiments for suspensions with monodisperse and polydisperse particles provide evidence for this new IB method's potential for solving the problems of extrusion flow. 
Iman Aganj  University of Minnesota  10/5/2009  10/7/2009 
Patrick Anderson  Technische Universiteit Eindhoven  10/10/2009  10/16/2009 
Shelley L. Anna  Carnegie Mellon University  10/10/2009  10/16/2009 
Arezoo Ardekani  Massachusetts Institute of Technology  10/13/2009  10/16/2009 
Paulo E. Arratia  University of Pennsylvania  10/10/2009  10/15/2009 
Paul J. Atzberger  University of California, Santa Barbara  10/11/2009  10/17/2009 
Nusret Balci  University of Minnesota  9/1/2009  8/31/2010 
Leah Bar  University of Minnesota  10/5/2009  10/7/2009 
Thomas Batard  Université de La Rochelle  10/3/2009  10/8/2009 
Peter W. Bates  Michigan State University  10/2/2009  10/5/2009 
Jennifer Beichman  University of Michigan  9/1/2009  5/31/2010 
Andrew Belmonte  Pennsylvania State University  10/10/2009  10/14/2009 
Antony N. Beris  University of Delaware  10/11/2009  10/16/2009 
Leonid Berlyand  Pennsylvania State University  10/13/2009  10/16/2009 
Michel Berthier  Université de La Rochelle  10/3/2009  10/8/2009 
Andrea L. Bertozzi  University of California, Los Angeles  10/4/2009  10/7/2009 
Meredith Betterton  University of Colorado  9/29/2009  10/2/2009 
Michael Booty  New Jersey Institute of Technology  10/10/2009  10/16/2009 
Olus N. Boratav  Corning Incorporated  10/10/2009  10/17/2009 
John F. Brady  California Institute of Technology  10/10/2009  10/16/2009 
Richard J. Braun  University of Delaware  9/1/2009  12/20/2009 
Michael P. Brenner  Harvard University  10/4/2009  10/5/2009 
Xavier Bresson  University of California, Los Angeles  10/4/2009  10/7/2009 
MariaCarme T. Calderer  University of Minnesota  9/1/2009  6/30/2010 
Christine Cardinal  University of Minnesota  10/12/2009  10/16/2009 
Lawrence Carin  Duke University  10/4/2009  10/7/2009 
Gunnar Carlsson  Stanford University  9/30/2009  10/2/2009 
Alexey Castrodad  University of Minnesota  10/5/2009  10/7/2009 
Bruce Caswell  Brown University  10/14/2009  10/17/2009 
Hector D. Ceniceros  University of California, Santa Barbara  10/11/2009  10/16/2009 
Chi Hin Chan  University of Minnesota  9/1/2009  8/31/2010 
Bernard Chazelle  Princeton University  10/3/2009  10/5/2009 
Xianjin Chen  University of Minnesota  9/1/2008  8/31/2010 
Eric Choate  University of North Carolina  10/10/2009  11/10/2009 
David Chock  Ford  10/4/2009  10/5/2009 
Peter Constantin  University of Chicago  10/13/2009  10/14/2009 
L. Pamela Cook  University of Delaware  9/6/2009  12/20/2009 
Michael Earl Cromer Jr  University of Delaware  9/1/2009  12/31/2009 
Qing Cui  University of Minnesota  10/1/2009  10/2/2010 
Jérôme Darbon  École Normale Supérieure de Cachan  10/3/2009  10/7/2009 
Morton Denn  City College, CUNY  10/12/2009  10/16/2009 
Charles Doering  University of Michigan  8/15/2009  6/15/2010 
Julio Duarte  Eastman Kodak Company  10/5/2009  10/7/2009 
Jens Eggers  University of Bristol  10/10/2009  10/17/2009 
Bjorn Engquist  University of Texas  10/11/2009  10/16/2009 
Charles L. Epstein  University of Pennsylvania  9/29/2009  10/2/2009 
Katia Estabridis  Naval Air Warfare Center  10/4/2009  10/7/2009 
Dean M. Evasius  National Science Foundation  9/29/2009  10/2/2009 
Randy H. Ewoldt  University of Minnesota  9/1/2009  8/31/2010 
Angbo Fang  Hong Kong University of Science and Technology  9/10/2009  10/18/2009 
Matt Feiszli  Yale University  10/4/2009  10/7/2009 
James J. Feng  University of British Columbia  10/11/2009  10/16/2009 
Xiaobing Feng  University of Tennessee  10/2/2009  10/31/2009 
David Finn  RoseHulman Institute of Technology  9/1/2009  11/23/2009 
Arjuna Flenner  Naval Air Warfare Center  10/4/2009  10/7/2009 
Mark Gregory Forest  University of North Carolina  9/11/2009  10/20/2009 
Richard Garcia  University of Puerto Rico  10/14/2009  10/15/2009 
Donald Geman  Johns Hopkins University  10/4/2009  10/6/2009 
Sandip Ghosal  Northwestern University  9/21/2009  12/12/2009 
Robert Ghrist  University of Pennsylvania  10/3/2009  10/5/2009 
Anna Gilbert  University of Michigan  10/2/2009  10/5/2009 
Yuliya Gorb  University of Houston  10/11/2009  10/17/2009 
Michael D. Graham  University of Wisconsin  9/1/2009  12/22/2009 
Xianfeng David Gu  SUNY  10/4/2009  10/7/2009 
Thomas C. Hagen  University of Memphis  9/1/2009  12/31/2009 
Thomas Hagstrom  University of New Mexico  9/29/2009  10/2/2009 
Brian Haines  Pennsylvania State University  10/11/2009  10/14/2009 
Oliver Harlen  University of Leeds  10/10/2009  10/16/2009 
Ole Hassager  Technical University of Denmark  10/11/2009  10/16/2009 
Xuming He  University of Illinois at UrbanaChampaign  9/29/2009  10/2/2009 
Juan Pablo HernandezOrtiz  National University of Colombia  10/11/2009  10/16/2009 
Gary Arthur Hewer DR.  Naval Air Warfare Center  10/4/2009  10/7/2009 
Mary Ann Horn  National Science Foundation  9/29/2009  10/6/2009 
Anette (Peko) Hosoi  Massachusetts Institute of Technology  10/13/2009  10/16/2009 
Xianpeng Hu  University of Pittsburgh  10/10/2009  10/15/2009 
Martien A. Hulsen  Technische Universiteit Eindhoven  10/10/2009  10/16/2009 
Yunkyong Hyon  University of Minnesota  9/1/2008  8/31/2010 
Mark Iwen  University of Minnesota  9/1/2008  8/31/2010 
Srividhya Jeyaraman  University of Minnesota  9/1/2008  8/31/2010 
Lijian Jiang  University of Minnesota  9/10/2008  8/31/2010 
Mihailo Jovanovic  University of Minnesota  9/11/2009  6/10/2010 
Behzad KamgarParsi  Office of Naval Research  10/4/2009  10/7/2009 
Joanna KaniaBartoszynska  National Science Foundation  9/29/2009  10/2/2009 
Justin C.T. Kao  Massachusetts Institute of Technology  10/10/2009  10/16/2009 
Markus Keel  University of Minnesota  10/4/2009  10/5/2009 
Markus Keel  University of Minnesota  7/21/2008  6/30/2010 
Bamin Khomami  University of Tennessee  10/11/2009  10/16/2009 
Hyejin Kim  University of Minnesota  9/1/2009  8/31/2010 
KwangYeon Kim  Kangwon (Kangweon) National University  10/9/2009  10/17/2009 
Ron Kimmel  TechnionIsrael Institute of Technology  10/4/2009  10/7/2009 
Daniel J. Klingenberg  University of Wisconsin  10/11/2009  10/16/2009 
Pawel Konieczny  University of Minnesota  9/1/2009  8/31/2010 
Peter R. Kramer  Rensselaer Polytechnic Institute  10/10/2009  10/17/2009 
Andrew M. Kraynik  Sandia National Laboratories  10/11/2009  10/16/2009 
Satish Kumar  University of Minnesota  10/12/2009  10/16/2009 
Tony Ladd  University of Florida  10/11/2009  10/15/2009 
Diane Lambert  Google Inc.  10/3/2009  10/5/2009 
Ronald G. Larson  University of Michigan  9/12/2009  12/22/2009 
Triet Minh Le  Yale University  10/4/2009  10/7/2009 
Claude Le Bris  CERMICS  10/11/2009  10/15/2009 
Federico Lecumberry  University of the Republic  10/4/2009  10/7/2009 
Yann LeCun  New York University  10/4/2009  10/7/2009 
ChiunChang Lee  National Taiwan University  10/22/2009  6/30/2010 
YoungJu Lee  Rutgers University  9/11/2009  12/31/2009 
Christophe Lenglet  University of Minnesota  10/5/2009  10/7/2009 
Marta Lewicka  University of Minnesota  9/1/2009  6/30/2010 
Yi Li  University of Iowa  9/30/2009  10/1/2009 
Yi Li  Stevens Institute of Technology  9/16/2009  12/17/2009 
Yongfeng Li  University of Minnesota  9/1/2008  8/31/2010 
Zhilin Li  North Carolina State University  10/11/2009  10/16/2009 
Zhi (George) Lin  University of Minnesota  9/1/2009  8/31/2010 
Chun Liu  University of Minnesota  9/1/2008  8/31/2010 
Deborah F. Lockhart  National Science Foundation  9/29/2009  10/2/2009 
Ellen K. Longmire  University of Minnesota  9/1/2009  6/30/2010 
John Lowengrub  University of California, Irvine  10/11/2009  10/16/2009 
Tie Luo  National Science Foundation  9/29/2009  10/2/2009 
Yi Ma  University of Illinois at UrbanaChampaign  10/4/2009  10/7/2009 
Christopher Macosko  University of Minnesota  10/12/2009  10/16/2009 
Yasunori Maekawa  Kobe University  9/7/2009  3/1/2010 
Krishnan Mahesh  University of Minnesota  9/1/2009  6/30/2010 
Kara Lee Maki  University of Minnesota  9/1/2009  8/31/2010 
Vasileios Maroulas  University of Minnesota  9/1/2008  8/31/2010 
Luca Martinetti  University of Minnesota  10/12/2009  10/16/2009 
Nader Masmoudi  New York University  10/13/2009  10/16/2009 
Gareth Huw Mckinley  Massachusetts Institute of Technology  10/11/2009  10/16/2009 
Facundo Mémoli  Stanford University  10/4/2009  10/7/2009 
Mario Micheli  University of California, Los Angeles  10/4/2009  10/7/2009 
Petar Minev  Texas A & M University  10/11/2009  10/17/2009 
Sorin Mitran  University of North Carolina  10/11/2009  10/16/2009 
JeanMichel Morel  École Normale Supérieure de Cachan  10/4/2009  10/7/2009 
Yoichiro Mori  University of Minnesota  9/1/2009  6/30/2010 
Alexander Morozov  University of Edinburgh  10/11/2009  10/17/2009 
Jeffrey F. Morris  City College, CUNY  10/12/2009  10/15/2009 
Susan J. Muller  University of California, Berkeley  10/10/2009  10/16/2009 
Tristan Nguyen  Office of Naval Research  10/4/2009  10/7/2009 
Monika Nitsche  University of New Mexico  9/1/2009  12/22/2009 
David Olagunju  University of Delaware  10/10/2009  10/16/2009 
Cecilia OrtizDuenas  University of Minnesota  9/1/2009  8/31/2010 
Hans G. Othmer  University of Minnesota  9/1/2009  6/30/2010 
Matteo Pasquali  Rice University  10/11/2009  10/16/2009 
Arlie O. Petters  Duke University  10/3/2009  10/5/2009 
Ronald Phillips  University of California, Davis  10/11/2009  10/16/2009 
Tim Phillips  Cardiff University  10/10/2009  10/16/2009 
Todd Plantenga  Sandia National Laboratories  10/22/2009  10/23/2009 
Harald Pleiner  Max Planck Institute for Polymer Research  9/12/2009  10/17/2009 
Craig T. Poling  Lockheed Martin  10/3/2009  10/5/2009 
Rob Poole  University of Liverpool  10/10/2009  10/17/2009 
Keith Promislow  Michigan State University  10/10/2009  10/16/2009 
Ignacio Ramirez  University of Minnesota  10/5/2009  10/7/2009 
Gregory J. Randall  University of the Republic  10/5/2009  10/7/2009 
Weiqing Ren  New York University  10/14/2009  10/16/2009 
Michael Renardy  Virginia Polytechnic Institute and State University  9/1/2009  12/20/2009 
Yuriko Renardy  Virginia Polytechnic Institute and State University  9/1/2009  12/20/2009 
Rosemary Renaut  Arizona State University  9/29/2009  10/2/2009 
Juan Mario Restrepo  University of Arizona  8/11/2009  6/15/2010 
Donald Richards  Pennsylvania State University  9/30/2009  10/5/2009 
Fred Roberts  Rutgers University  9/29/2009  10/2/2009 
Scott Alan Roberts  University of Minnesota  10/12/2009  10/16/2009 
Peter Cornelis Roozemond  Technische Universiteit Eindhoven  10/10/2009  10/18/2009 
Jonathan P. Rothstein  University of Massachusetts  10/11/2009  10/14/2009 
Firooz Sadjadi  Lockheed Martin  10/5/2009  10/7/2009 
Gaurab Samanta  University of Minnesota  10/12/2009  10/16/2009 
Evelyn Sander  George Mason University  9/29/2009  10/2/2009 
Fadil Santosa  University of Minnesota  7/1/2008  6/30/2010 
Guillermo R. Sapiro  University of Minnesota  10/5/2009  10/7/2009 
Arnd Scheel  University of Minnesota  9/1/2009  6/30/2010 
George R Sell  University of Minnesota  9/1/2009  6/30/2010 
Tsvetanka Sendova  University of Minnesota  9/1/2008  8/31/2010 
Gregory Seregin  University of Oxford  9/20/2009  10/18/2009 
Shuanglin Shao  University of Minnesota  9/1/2009  8/31/2010 
Eric S. G. Shaqfeh  Stanford University  10/10/2009  10/13/2009 
David H. Sharp  Los Alamos National Laboratory  10/3/2009  10/6/2009 
Michael J. Shelley  New York University  10/11/2009  10/13/2009 
Steve Shkoller  University of California, Davis  10/11/2009  10/16/2009 
Ali Shokoufandeh  Drexel University  10/4/2009  10/7/2009 
Michael S. Siegel  New Jersey Institute of Technology  10/11/2009  10/15/2009 
Linda B. Smolka  Bucknell University  10/11/2009  10/16/2009 
Daniel Spirn  University of Minnesota  9/8/2009  6/1/2010 
Pablo Sprechmann  University of Minnesota  10/5/2009  10/7/2009 
Paul H. Steen  Cornell University  10/15/2009  12/15/2009 
Victor Steinberg  Weizmann Institute of Science  10/12/2009  10/16/2009 
Panagiotis Stinis  University of Minnesota  9/1/2009  6/30/2010 
Emily Stone  Utah State University  9/29/2009  10/2/2009 
Howard Stone  Harvard University  10/11/2009  10/15/2009 
Huan Sun  Pennsylvania State University  8/16/2009  12/15/2009 
Radhakrishna Sureshkumar  Washington University  10/11/2009  10/16/2009 
Vladimir Sverak  University of Minnesota  9/1/2009  6/30/2010 
Mark Taylor  Sandia National Laboratories  9/1/2009  12/22/2009 
JeanLuc Thiffeault  University of Wisconsin  9/1/2009  6/30/2010 
Chad Michael Topaz  Macalester College  9/1/2009  6/30/2010 
Karel Tuma  Charles University in Prague  10/9/2009  10/17/2009 
Patrick Theodore Underhill  Rensselaer Polytechnic Institute  10/11/2009  10/15/2009 
Alan VanNevel  Naval Air Warfare Center  10/4/2009  10/7/2009 
Paula Andrea Vasquez  University of Delaware  10/10/2009  10/16/2009 
Miguel VelezReyes  University of Puerto Rico  10/4/2009  10/6/2009 
René Vidal  Johns Hopkins University  10/4/2009  10/6/2009 
Petia M. Vlahovska  Dartmouth College  10/11/2009  10/16/2009 
Jesenko Vukadinovic  College of Staten Island, CUNY  10/11/2009  10/16/2009 
Lynn M. Walker  Carnegie Mellon University  10/10/2009  10/16/2009 
Shawn W. Walker  New York University  10/10/2009  10/16/2009 
Changyou Wang  University of Kentucky  9/1/2009  6/15/2010 
Qi Wang  University of South Carolina  10/12/2009  10/17/2009 
Sijue Wu  University of Michigan  9/1/2009  6/5/2010 
Wei Xiong  University of Minnesota  9/1/2008  8/31/2010 
Tsuyoshi Yoneda  University of Minnesota  9/4/2009  8/31/2010 
Laurent Younes  Johns Hopkins University  10/4/2009  10/7/2009 
Haijun Yu  Purdue University  10/11/2009  10/17/2009 
Arghir Dani Zarnescu  University of Oxford  10/10/2009  10/17/2009 
Linbao Zhang  University of Maryland  10/10/2009  10/16/2009 
Likun Zheng  University of Minnesota  10/12/2009  10/16/2009 
Weigang Zhong  University of Minnesota  9/8/2008  8/31/2010 
Chunfeng Zhou  University of Minnesota  10/12/2009  10/16/2009 
Meijun Zhu  University of Oklahoma  10/4/2009  10/7/2009 