1. Laboratory for Atomistic and Molecular Mechanics, Dept. of Civil and Environmental Engineering, 77 Massachusetts Ave. Room 1-235A&B, Cambridge, MA; and Dept. of Materials Science and Engineering, Massachusetts Institute of Technology 77 Massachusetts Ave. Cambridge, MA 02139.
2. Laboratory for Atomistic and Molecular Mechanics, Dept. of Civil and Environmental Engineering, 77 Massachusetts Ave. Room 1-235A&B, Cambridge, MA.
3. Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, 77 MA Ave. Room 1-235A&B, Cambridge, MA (corresponding author).