Jun
10
11:50am11:50am

Analysis of Incompressible Viscoelastic Fluids

By Fanghua Lin, NYU and NYU Shanghai

One of the common origin and manifestations of anomalous phenomena in complex fluids are different "elastic" effects. Many rheological and hydrodynamic properties of such fluids can be attributed to the special coupling between the transportation of the internal variables and the induced elastic stress. One of the best examples is that of Oldroyd model for viscoelastic fluids. In this talk, I shall discuss briefly some recent analytic studies on the Oldroyd model.

 

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Jun
10
11:20am11:20am

Mathematics of Complex Fluids either Living or Critical to Life

By Gregory Forest, University of North Carolina at Chapel Hill

Remarkable advances in instrumentation and experimental technique provide unprecedented insight into in vivo biological fluids. Experiments and data will be presented from three such fluids:  native DNA within the nucleus of live yeast; highly irregular plasma membrane morphologies of diverse mammalian cell lines; and Nature's barrier fluid, mucus, which protects every organ in the human body not covered by skin.  Analysis of the data, mathematical models we have derived to understand these biological systems, results thus far,  and remaining significant open problems, will be presented.

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Jun
10
10:40am10:40am

Some Surprises and Open Questions in Active Matter

By Steve Granick, Institute of Basic Science and UNIST

A fundamental challenge of modern soft matter physics is to form structure that is not frozen in place but instead reconfigures internally driven by energy throughput and adapts to its environment robustly. Predicated on fluorescence imaging at the single-particle level, this talk describes quantitative studies of how this can happen. With Janus colloidal clusters, we show the powerful role of synchronized motion in self-assembly. In living cells, we find that transportation efficiency problems bear a provocative parallel with polymer chain trajectories with their spatial extent, and with jammed matter in their time evolution. A picture emerges in which simple experiments, performed at single-particle and single-molecule resolution, can dissect macroscopic phenomena in ways that surprise.

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Jun
10
9:40am 9:40am

Mobile and impeding boundaries in thermal convection

By Jun Zhang, NYU and NYU Shanghai

Thermal convection is ubiquitous in nature. It spans from a small cup of tea to the internal dynamics of the earth. In this talk, I will discuss a few experiments where boundaries to the fluid play surprising roles in changing the behaviors of a classical Rayleigh-Bénard convection system. In one, mobile boundaries lead to regular large-scale oscillations that involve the entire system. This could be related to the continental kinetics on earth over the past two billion years, as super-continents formed and broke apart in cyclic fashion. In another experiment, we found that seemingly impeding partitions in thermal convection can boost the overall heat transport by several folds, once the partitions are properly arranged, thanks to an unexpected symmetry-breaking bifurcation.

 

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Jun
10
9:00am 9:00am

Active fluids and structures

By Michael Shelley, New York University

Swimming, or self-locomotion through a fluid, is done by algae, bacteria, birds, and whales. It even occurs inside of cells. Swimming becomes especially fascinating when it involves collectives that interact through the fluid. I'll talk about a few examples. One involves experiments and models that explore the interactions of many flapping flyers. Surprising effects occur due to the ability of the fluid to store information on the history of the flow. At a very different scale I'll discuss how biological motor proteins can collectively drive flow and transport in the cell, such as the "swimming" and positioning of the pronuclear complex prior to cell division.

 

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