[1] Czech Univ Life Sci Prague, Dept Mech Engn, Kamycka 129, Prague 6, Czech Republic
[2] Czech Univ Life Sci Prague, Dept Mat Sci & Mfg Technol, Kamycka 129, Prague 6, Czech Republic
[3] Univ Sumatera Utara, Dept Agr Engn, Prof A Sofyan 3,Kampus USU, Medan, Indonesia