1. Mem. ASME Department of Mechanical Engineering, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332
2. School of Mathematics, Georgia Institute of Technology, Atlanta, GA 30332
3. Mem. ASME Department of Mechanical Engineering, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 e-mail: