Seminars

ME/IE 8773-8774
THERMODYNAMICS AND HEAT TRANSFER SERIES (1130 ME)
Topic: Heat Transfer and the Environment
Host: Terrence W. Simon

Heat Transfer in Nano Porous Media: Phonons in
Gage Crystals and Ion-Doped Powders

by

Massoud Kaviany
Department of Mechanical Engineering
and the Applied Physics Program
University of Michigan
Ann Arbor, MI 41809

Wednesday, April 6, 2005
3:30-5:00 p.m.
Room 1130 ME
Coffee and cookies will be available at 3:15 p.m. in Room 1130 ME before the seminar

Abstract: Two examples of porous nano structures in heat transfer research are presented. These involve phonon damping and phonon pumping. The low phonon conductivity of nano porous (cage) dielectric crystals is described using molecular dynamics (MD) simulations, along with the Green-Kubo autocorrelation integral decay. In metal-organic frameworks (considered for hydrogen storage), phonon localization (damping) occurs through the bridges connecting subunits. Enhanced, laser cooling of rare-earth ion-doped nano powders, based on anti-Stokes luminescence (involving phonon absorption, i.e., pumping), will be discussed. These include an enhanced, absorption phonon side band (due to extended high energy phonons in nano structures) and photon localization due to multiple pore scattering.

Bio: Massoud Kaviany is a Professor in the Department of Mechanical Engineering, and is also with the Applied Physics Program, at the University of Michigan, where he has been since 1986. His Ph.D. is from the University of California-Berkeley in 1979. His area of teaching and research is heat transfer, with a particular interest in porous media.

Informal Faculty Luncheon: Wednesday, April 6, 2005, 12:00 noon. Meet in 1100 ME and walk to lunch with other faculty. Prof. Massoud Kaviany will be able to attend.