Description:

Speaker:

James F. Gilchrist, Ruth H. and Sam Madrid Professor, Chemical & Biomolecular Engineering, Lehigh University

Title:

Going Against the Grain: Microrollers Flow Uphill as Granular Media

Abstract: 

Granular media is often referred to as a quintessential example of complexity in soft matter. Their interactions are localized to their nearest neighbors, and yet nonlocal length scales appear in granular flows and force chain networks that are defined by their complex geometric arrangement. Beyond their complex geometry and inertial profiles, granular media are embedded with surface science that define energy storage and dissipation. This experimental research explores collective response of field-responsive granular media in the form of microrollers. These microrollers are manipulated by rotating magnets that generate torque at the particle-scale and influence magnetic particle-particle attraction that can be loosely correlated as influencing friction in the system. The result is kinematics that scale as granular flows that readily flow uphill with a negative angle of repose, segregate, and generate uncommon collective behavior.

Speaker Bio:

Professor Gilchrist's research and scholarly activities are designed to impact both science and engineering through fundamental studies of particulate systems. From an engineering viewpoint, particle technology is ubiquitous, including pharmaceutical, chemical, agricultural, food, cosmetic, ceramic, electronic, and mining processes and in an uncountable number of natural processes including sediment transport in rivers, dune formation, and blood flow. An overarching objective of Gilchrist's research is to develop a better understanding of these far-from-equilibrium particulate processes exhibiting complexity and self-organization.

Location:

In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/96193851325
Passcode: NICO23

About the Speaker Series:

Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems and data science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.