1. Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Avenue, PO Box 20537, 1678 Nicosia, Cyprus
2. National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, PO Box MG-36, 077125 Magurele, Romania
3. National Institute of Materials Physics, RO-077125 Magurele, Romania