1. a Faculty of Mechanical Engineering, University of Ljubljana , Aškerčceva 6, SI-1000, Ljubljana, Slovenia
2. b Faculty of Mechanical Engineering, University of Ljubljana , Aškerčceva 6, SI-1000, Ljubljana, Slovenia E-mail:
3. c Litostroj EI d.o.o. , Litostrojska 50, SI-1000, Ljubljana, Slovenia E-mail: