1. Department of Mechanical and Aerospace Engineering, The University of California—San Diego, La Jolla, California 92093, United States
2. Department of Mechanical and Aerospace Engineering, The University of California—Irvine, Irvine, California 92697, United States
3. Department of Mechanical Engineering, The University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
4. Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37235-1592, United States