Professor Robert D. Tzou of the University of Missouri gave a seminar Tuesday, April 15, on thermal lagging in multi-carrier systems. Tzou explored the lagging behavior for heat transport in systems containing multiple carriers by extending the microscopic two-step heating model where electrons and phones are two main carriers. He outlined fundamental behavior of thermal lagging, emphasizing its perfect correlations to the existing macroscopic and microscopic models in the various limits. Tzou also demonstrated, for the first time, that the system containing n carriers will display thermal lagging of the (n-1)^th order, resulting in new energy equations never seen before. He then provided an example to illustrate these high-order effects in thermal lagging. The seminar was hosted by Dr. Kwon.