Author(s):
1. Jasmina Bogdanović-Jovanović, Faculty of Mechanical Engineering in Niš, Serbia
2. Zivojin Stamenkovic, Faculty of Mechanical Engineering in Niš, Serbia
3. Živan Spasić, Faculty of Mechanical Engineering in Niš, Serbia
4. Jelena Petrović, Faculty of Mechanical Engineerning, Serbia
5. Milos Kocic, Faculty of Mechanical Engineering in Niš, Serbia