1. Civil and Environmental Engineering Dept., Utah State Univ., EL 211, 4110 Old Main Hill, Logan, UT 84322-4110 Former Graduate Research Assistant, Agricultural and Biological Engineering Dept., Univ. of Florida, P.O. Box 110570, Gainesville, FL 32611.
2. Professor, Agricultural and Biological Engineering Dept., Univ. of Florida, P.O. Box 110570, Gainesville, FL 32611 (corresponding author).
3. Associate Professor, Agricultural and Biological Engineering Dept., Univ. of Florida, 18905 SW 280th St, Homestead, FL 33031.
4. Research Associate, Agricultural and Biological Engineering Dept., Univ. of Florida, P.O. Box 110570, Gainesville, FL 32611.