1. Transilvania University of Brasov, Faculty of Materials Science and Engineering, Department of Materials Science, 500036 Brasov, Romania, petru.muresan@unitbv.ro
2. Transilvania University of Brasov, Faculty of Materials Science and Engineering, Department of Materials Science, 500036 Brasov, Romania, milosan@unitbv.ro
3. Territorial Labor Inspectorate of Brasov, Romania, Associate Professor, Transilvania University of Brasov, Faculty of Materials Science and Engineering, Department of Materials Science, 500036 Brasov, Romania, dorin_senchetru@yahoo.com
4. Territorial Labor Inspectorate of Brasov, 500036 Brasov, Romania, adrianreit@yahoo.com