1. Department of Mechanical Systems Engineering, Hiroshima University, 1-4-1 Kagamiyama,
Higashi-Hiroshima, Hiroshima, 739-8527 Japan.
2. Division of Energy and Environmental Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima,
Hiroshima, 739-8527 Japan.