1. U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
2. NRC postdoctoral associate, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
3. ASEE postdoctoral fellow, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
4. Department of Mechanical Engineering, Vanderbilt University, 2400 Highland Avenue, Nashville, Tennessee 37212, United States