1. Lecturer, School of Science and Engineering, Univ. of Dundee, Dundee DD1 4HN, UK (corresponding author). ORCID: .
2. Professor, Dept. of Engineering Mathematics and Internetworking, Dalhousie Univ., Halifax, NS, Canada B3J 2X4.
3. Professor, Dept. of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401.