Author(s):
1. Saša Pavlović, Faculty of Mechanical Engineering in Niš, Serbia
2. Velimir Stefanovic, Faculty of Mechanical Engineering in Niš, Serbia
3. Bellos Evangelos, National Technical University of Athens, Zografou, Heroon Polytechniou , Greece
4. Christos Tzivanidis, National Technical University of Athens, Zografou, Heroon Polytechniou , Greece