1. Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
2. Thermal Management Research Group, Efficient Energy Transfer (ηET) Department, Bell Laboratories Ireland, Alcatel-Lucent Ireland Ltd., Blanchardstown Business & Technology Park, Snugborough Road, Dublin 15, Ireland
3. Stokes Institute, University of Limerick, Limerick, Ireland