Lewis E. Johns is Professor Emeritus of Chemical Engineering at the University of Florida, Gainesville. He received his B.S. (1957) and Ph.D. (1964) in Chemical Engineering from Carnegie Institute of Technology. He worked as a research scientist at Dow Chemical in Midland, Michigan (1961–1967), and then joined the University of Florida, where he served on the faculty from 1967 to 2019. Ranga Narayanan is Distinguished Professor of Chemical Engineering at the University of Florida, Gainesville. He received his B.Tech. (Honors) in Chemical Engineering from the University of Madras (1971), and his M.S. (1973) and Ph.D. (1978) from the Illinois Institute of Technology. He worked as a research engineer at the Amoco Research Center in Naperville, Illinois (1976–1981), and has been on the faculty at the University of Florida since 1981.