1. Department of Mechanical Engineering, Engineering Faculty, Diponegoro University, Jl. Prof. Sudharto, SH., Semarang 50275, Indonesia
2. College of Engineering, Pukyong National University, 365 Sinseon-ro, Nam-gu, Busan 608-739, Korea
3. Chemical Engineering Department, Vocational School, Diponegoro University, Jl. Prof. Sudharto, SH., Semarang 50275, Indonesia