1. Faculty of Mechanical Engineering, University Ss. Cyril and Methodius, Skopje 1000, Republic of Macedonia e-mail:
2. Mem. ASME Faculty of Engineering and Applied Science, UOIT-University of Ontario Institute of Technology, Oshawa, ON L1H 7K4, Canada e-mail:
3. Mem. ASME Faculty of Mechanical Engineering, University Ss. Cyril and Methodius, Skopje 1000, Republic of Macedonia e-mail: