1. Faculty of Industrial Chemistry and Environmental Engineering; “Politehnica” University of Timişoara; Piaţa Victoriei no. 2 Timişoara 300006 Timiş Romania
2. Lab. Magnetic Fluids; Center for Fundamental and Advanced Technical Research; Romanian Academy-Timişoara Branch Bv. M. Viteazu 24 Timişoara RO-300223 Romania