L. L. Simpson is a Corporate Engineering Fellow in Union Carbide's Central Engineering Department at the Technical Center, South Charleston, West Virginia. His past work includes plant design and startup, and for the past 18 years, fluid dynamics specialization. For the last ten years he has also managed the Heat Transfer and Fluid Dynamics Group. He has written several articles on different aspect of fluid dynamics, including a chapter in the book “Turbulence in Mixing Operations.” He has a BSChE from Purdue University and an MSChE from West Virginia University. He is a registered professional engineer in West Virginia and has been active in AIChE.