Dr. Manoj K. Chaudhury, Franklin J. Howes Jr. Distinguished Professor, Department of Chemical Engineering, Lehigh University, Bethlehem, PA, will present the CLSE seminar on March 7th, 2012.
This event is free and open to the public.
The seminar will be held in Room 401, Engineering West Building from 12:30-2:00PM. Refreshments will be served.
Diffusive Motion with Non-linear Friction
ABSTRACT: We study experimentally the behaviors of several driven diffusive systems that involve the sliding and rolling of small solid objects or liquid drops on a surface with an external noise and an external field. The displacement statistics here are non-Gaussian at short observation time, but they tend towards a Gaussian behavior at long time scale. Furthermore, in each of these cases, the drift velocity increases sub-linearly, but the diffusivity increases super-linearly with the strength of the noise. These observations reflect the underlying non-linear friction control of their stochastic dynamics. Specific experiments have also been designed to study the hopping of a small object over a physical barrier assisted by an external noise. These results mimic the classical Arrhenius behavior from which an effective temperature may be deduced that can be compared with the Einstein's ratio of diffusivity and mobility. All the drifted diffusive systems studied here exhibit substantial negative fluctuations of displacement at a short observation time that diminishes at longer time scale. Using the integrated fluctuation theorem, we characterize the persistence time of negative fluctuations in terms of the diffusivity and the drift velocity that can be measured experimentally. Relevance of these studies in the noise induced motion of liquid droplets in micro-heat exchangers will be discussed.
BIO: Manoj K. Chaudhury received his PhD in chemical engineering from the University of Buffalo in 1984. After working in the central research and development division of Dow Corning Corporation for eight years, he joined the faculty of chemical engineering at Lehigh University in 1993. He is now a professor of the department of chemical engineering at Lehigh University and holds the Franklin J. Howes Jr. Distinguished Professor Chair in the P.C Rossin College of Engineering. At Lehigh University, he directed an NSF sponsored Center of Polymer Interfaces from 1996 to 2003, which supported research of about ten faculty members. Manoj Chaudhury's research interests are in statistical mechanics, continuum mechanics and surface science. For his research accomplishments, he received several recognitions that include Victor K. LaMer Award from the colloid and surface science division of ACS, the Adhesion Society's award of excellence in adhesion sponsored by 3M, the Herbert Doan Award for innovative research from Dow Chemical Co., elected fellowship to American Physical Society, Ingenuity award from the Rossin College of engineering for distinguished teaching and research as well as a few best paper awards. He has published more than hundred papers, was awarded patents in adhesives and integrated electronic packaging, presented numerous invited lectures and organized or chaired several national conferences including a Gordon conference. Currently, Chaudhury is an associate editor of the journal Biointerphases, which is jointly published by American Vacuum Society and American Institute of Physics. He has supervised the research of about a dozen PhD students and a dozen postdoctoral fellows, who now occupy various prominent positions in academia, government labs and industry.