1. Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, 500 Pillsbury Drive S.E., Minneapolis, MN 55455
2. Department of Mathematics, Kansas State University, 138 Cardwell Hall, Manhattan, KS 66506
3. Department of Computer Simulations and Mechanics of Composite Materials, Institute for Superhard Materials of the National Academy of Sciences of Ukraine, Kiev 04074, Ukraine