1. Department of Mathematics, Sidho-Kanho-Birsha University, Purulia 1 , West Bengal 723104, India
2. Department of Mathematics, Government General Degree College Ranibandh 2 , Bankura, West Bengal 722135, India
3. Integrated Science Education & Research Centre (ISERC) Visva-Bharati 3 , Santiniketan, West Bengal 731235, India
4. Laboratory on Convective Heat and Mass Transfer, Tomsk State University 4 , Tomsk 634050, Russia