1. Department of Mechanical Engineering, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa
2. Department of Energy Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3-9, H-1111 Budapest, Hungary
3. DSD Product Development, MOL Hungarian Oil and Gas Public Limited Company, Post Office Box 1, H-2443 Százhalombatta, Hungary