1. Faculty of Engineering, Mechanical and Process Engineering, University of Szeged, Moszkvai boulevard 5-7, Szeged 6725, Hungary E-mail: szangela@mk.u-szeged.hu
2. Uwatech Ltd, Majori str. 37, Cserszegtomaj 8372, Hungary E-mail: info@uwatechkft.t-online.hu