NOAH D. MANRING, PHD, is the Glen A. Barton Professor of fluid power and chair in the Mechanical and Aerospace Engineering Department at the University of Missouri. A former engineer for Caterpillar Inc. and Danfoss Power Solutions (formerly Sauer Sundstrand), he has experience developing hydraulic pumps and fluid power systems and controls. ROGER C. FALES, PHD, is an Associate Professor in the Mechanical and Aerospace Engineering Department at the University of Missouri. A former engineer for Caterpillar Inc., he has experience developing fluid power and off-highway machine systems and controls.