CaSO4 Scale Formation on Vibrated Piping System in the Presence Citric Acid W. Mangestiyono, J. Jamari, S. Muryanto and A. P. Bayuseno E3S Web Conf., 31 (2018) 01001 Published online: 21 February 2018 DOI: 10.1051/e3sconf/20183101001