1. Assistant Professor, Dept. of Mathematics, National Institute of Technology, Calicut, Kozhikode, Kerala 673601, India (corresponding author).
2. Research Scholar, Dept. of Applied Mathematics, Indian School of Mines, Dhanbad, Jharkhand 826004, India.
3. Professor, Dept. of Applied Mathematics, Indian School of Mines, Dhanbad, Jharkhand 826004, India.