Bulletin of the American Physical Society
Fall 2020 Meeting of the APS New England Section
Volume 65, Number 21
Friday–Saturday, November 6–7, 2020; Virtual
Session A01: Plenary: Solid State and Material Sciences |
Hide Abstracts |
Chair: Dan Liu, University of Hartford |
Friday, November 6, 2020 2:00PM - 2:30PM |
A01.00001: Physics of Sand: Emergent Behavior in the Macro World Invited Speaker: Bulbul Chakraborty Diversity in the natural world emerges from the collective behavior of large numbers of interacting objects. The origin of collectively organized structures over the vast range of length scales from the subatomic to colloidal is the competition between energy and entropy. Thermal motion provides the mechanism for organization by allowing particles to explore the space of configurations. This well-established paradigm of emergent behavior breaks down for collections of macroscopic objects ranging from grains of sand to asteroids. In this macro-world, thermal motion is absent, and mechanical forces are all important. Surprisingly, we lack understanding of the basic, unifying principles that underlie the emergence of order in this world that we encounter in our everyday life. In this talk, I will explore the Statistical Mechanics of “sand”, and present a new paradigm for emergence of rigidity in these athermal systems. [Preview Abstract] |
Friday, November 6, 2020 2:30PM - 3:00PM |
A01.00002: The Role of Dilation in Discontinuous Shear Thickening Suspensions Invited Speaker: Eric Brown Concentrated suspensions of hard particles such as cornstarch in water exhibit Discontinuous Shear Thickening, a non-Newtonian fluid behavior in which an increasing shear rate causes the effective viscosity of the fluid to increase, and even crack like a solid. In recent years, the mechanics have been understood as a transition from a low-stress state to a high stress state as particles are pushed into frictional contact. Experimental measurements of the local shear profile and under different boundary conditions reveal that the local constitutive relation of the high-stress state is effectively frictional, where shear stress is proportional to normal stress, but not shear rate. The high-stress state is found intermittently along with dilation, indicating that stresses are transmitted along effectively frictional intermittent contact networks that form as dilation pushes the particle packing against the boundary. As the particles push against the boundary, it responds with a restoring force that is transmitted along the particle contact network. The scale of the stress in the high-stress state is thus determined by the effective stiffness of the boundary, which is usually determined by surface tension at the suspension-air interface in experiments. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700