1. Czestochowa University of Technology, Department of Physics, 42-201 Częstochowa, Poland
2. Czestochowa University of Technology, Institute of Thermal Machinery, 42-201 Częstochowa, Poland
3. Department of Applied Mechanics, Faculty of Mechanical Engineering, VŠB - Technical University of Ostrava, 708 33 Ostrava-Poruba, Czech Republic