1. GortEngovation (Biomechanics and Aerospace), 15 Southmere Avenue, Bradford, BD73NU, England, UK
2. Department of Mathematics, University of Dhaka, Dhaka-1000, Bangladesh
3. Aeronautical and Mechanical Engineering, Dept. Engineering and Mathematics, Sheffield, Hallam University, Sheaf Bldg, S11WB, Sheffield, England, UK