R. D. Ratnani
Wahid Hasyim University
Indonesia

H. Hadiyanto
Department of Chemical Engineering, Faculty of Engineering, Diponegoro University, Semarang – Indonesia
Indonesia

W. Widiyanto
Department of Animal Husbandry, Faculty of Animal and Agricultural Science, Diponegoro University, Semarang – Indonesia
Indonesia

M. A. Adhi
Department of Physics, Faculty of Mathematics And Natural Sciences, Universitas Negeri Semarang, Indonesia