1. Associate Professor, Dept. of Applied Mathematics, Indian School of Mines, Dhanbad, Jharkhand 826004, India (corresponding author).
2. Ph.D. Candidate, Dept. of Applied Mathematics, Indian School of Mines, Dhanbad, Jharkhand 826004, India.
3. Distinguished Professor; Caroline & William N. Lehrer Distinguished Chair in Water Engineering, Dept. of Biological and Agricultural Engineering and Zachry Dept. of Civil Engineering, Texas A and M Univ., 321 Scoates Hall, 2117 TAMU, College Station, TX 77843-2117.