The National Bureau of Standards Boulder Laboratories at Boulder, Colorado once again served as the host for the 1972 Cryogenic Engineering Conference. For the Cryogenic Engineering Conference it was like coming horne, for it was at the NBS Boulder Laboratories that the Cryogenic Engineering Conference was first conceived and held m 1954m connection with the dedication ofthe NBS Boulder Laboratories by President Dwight D. Eisenhower. The Cryogenic Engineering Conference IS grateful for the continuing support that the National Bureau of Standards has gIVen over the years, and which was expanded on July 1, 1971 when the NBS Boulder Laboratories assumed the secretariat function of the Conference from the National Academy of Sciences. Because of common interests in heat transfer, the 1972 Cryogemc Engineering Conference worked with the 13th National Heat Transfer Conference to develop a joint program m heat transfer. A majority ofthe papers presented in this cooperative effort are incIuded m V olume 18 of the Advances zn Cryogenic Engineerzng through the kmd permission ofthe 13th NatIOnal Heat Transfer Conference and are acknowl­ edged accordingly.