1. Professor Faculty of Mechanical Engineering, Koszalin University of Technology, Koszalin 75-620, Poland e-mail:
2. Associate Professor Faculty of Mechanical Engineering, Koszalin University of Technology, Koszalin 75-620, Poland e-mail:
3. Assistant Professor Faculty of Mechanical Engineering, Koszalin University of Technology, Koszalin 75-620, Poland e-mail: