An American chemical engineer noted for his work on mixing. He obtained his first degree in chemical engineering from the University of (p. 334) Pennsylvania in 1926 and worked as an engineer before becoming an academic. He was professor and head of chemical engineering at the University of Virginia. In 1946 he moved to the Illinois Institute of Technology as professor and director of the Department of Chemical Engineering. He joined Purdue University in 1955 and remained there until 1971. He was considered a world expert on design and application of large-scale mixing, mass transfer equipment, and on process design, and was president of AIChE in 1957.