1. Geosciences and Engineering Dept., Southwest Research Institute, 6220 Culebra Rd., San Antonio, TX 78238, US
2. Fire Technology Dept., Southwest Research Institute, 6220 Culebra Rd., San Antonio, TX 78238, US
3. Dept. of Electrical Engineering and Computer Science, University of Tennessee, 1520 Middle Dr., Knoxville, TN 37996, US