1. School of Engineering, 100 O'Shaughnessy Science Hall, University of St Thomas, 2115 Summit Avenue, St Paul, MN 55105-1079, USA
2. SEMS Corporate Research Laboratory, 3M Corporation, Building 235-3F-08, Maplewood, MN 55114-1000, USA; currently with the Department of Engineering Technology and Industrial Distribution, Texas A&M University, College Station, Texas 77843-3367, USA