1. Department
of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 220 S. 33rd Street, Philadelphia, Pennsylvania 19104, United States
2. School
of Engineering, Brown University, 184 Hope Street, Providence, Rhode Island 02912, United States
3. Department
of Materials Science and Engineering, University of Pennsylvania, 3231
Walnut Street, Philadelphia, Pennsylvania 19104, United States
4. Naval Research Laboratory, Washington, DC 20375, United States