Национальный институт стандартов и технологий
He was a visiting faculty at Princeton University(1982–83) and a visiting scientist at National Institute of Standards and Technology, Boulder, Colorado(1990–91). He was a visiting scientist in the National Institute of Standards and Technology, Boulder, Colorado (1990–91), in RWTH, Aachen, Germany (summer 1983 and summer 1999) and a visiting thermodynamics expert in Aspen Tech, Massachusetts, US (summer 1991).