1. Department of Mechanical and Industrial Engineering, M/C 251, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL 60607‐7022, USA
2. Department of Civil and Materials Engineering, M/C 246, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL 60607‐7022, USA
3. MicroFab Technologies, 1104 Summit Avenue, Plano, TX 75074, USA