1. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701.
2. Research Scientist, Dept. of Mechanical Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701 (corresponding author).
3. Asscoiate Professor, Dept. of Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701.
4. Associate Professor, Dept. of Mechanical Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701.