1. Department of Mathematics, Koneru Lakshmaiah Education Foundation, Deemed to be University, Green Fields, Vaddeswaram, Guntur 522502, India
2. Department of Mechanical Engineering, Koneru Lakshmaiah Education Foundation, Deemed to be University, Green Fields, Vaddeswaram, Guntur 522502, India (Corresponding author), e-mail: bnrao52@rediffmail.com, https://orcid.org/0000-0003-1620-6188