1. Postdoctoral Fellow, Biosystems and Agricultural Engineering Dept., Oklahoma State Univ., Stillwater, OK 74078.
2. Professor and Head, Biosystems and Agricultural Engineering Dept., Oklahoma State Univ., Stillwater, OK 74078 (corresponding author).
3. Professor, Kimberly Research and Extension Center, Univ. of Idaho, Kimberly, ID 84322.
4. Ivan’s Engineering, Inc., Centennial, CO 80121.