1. School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
2. School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
3. Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, USA
4. Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
5. School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, USA