1. Dept. of Civil Engineering, Indian Institute of Technology, Roorkee-247667, India; presently, Curtis Visiting Professor, School of Civil Engineering, Purdue Univ., West Lafayette, IN, 47907.
2. Dept. of Mechanical Engineering, Dehradun Institute of Technology, Dehradun-248001, India (corresponding author).
3. Dept. of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee-247667, India.