[1] Univ Minho, Phys Dept, CFUM UP, P-4800058 Guimaraes, Portugal
[2] Univ Coimbra, SEG CEMMPRE Ctr Mech Engn, Dept Mech Engn Mat & Proc, Rua Luis Reis Santos, P-3030788 Coimbra, Portugal
[3] Ducom Instruments Europe BV, Applicat Dev Lab, NL-9713 GX Groningen, Netherlands
[4] IPN LED & MAT Inst Pedro Nunes, Lab Ensaios Desgaste & Mat, Rua Pedro Nunes, P-3030199 Coimbra, Portugal
[5] Czech Tech Univ, Dept Control Engn, Tech 2, Prague 616627, Czech Republic