1. Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, South Carolina 29208, USA
2. Department of Electrical Engineering, University of South Carolina, 301 Main Street, Columbia, South Carolina 29208, USA
3. Electron Microscopy Center, University of South Carolina, 301 Main Street, Columbia, South Carolina 29205, USA
4. Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 3700 O'Hara Street, Pittsburgh, Pennsylvania 15261, USA
5. Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, Virginia 22904, USA