1. Mechanical Engineering Department University of California Santa Barbara CA 93106 USA
2. Mechanical Engineering Department University of British Colombia Vancouver BC V6T 1Z4 Canada
3. Materials Department University of California Santa Barbara CA 93106 USA
4. Leibniz Institute for New Materials Campus D2 2 66123 Saarbrücken Germany
5. School of Engineering University of Aberdeen King's College Aberdeen AB24 3UE UK