Dr. Mark J. Lewis, former chief scientist for the U.S. Air Force and president of the American Institute of Aeronautics and Astronautics (AIAA), will present a seminar 4:45-6:10 p.m. Wednesday, April 29, in Room G-31 Emerson Hall. His lecture is titled “Hypersonic Flight: Progress and Challenges on the Way to High Mach Systems.” The event is presented by the student chapter of the AIAA. To attend a dinner with Lewis and the AIAA chapter, contact Thomas Knight for reservations.