The rapidly expanding use of very low temperatures in research and high technology during the last several decades and the concurrent high degree of activity in cryogenic engineering have mutually supported each other, each improvement in refrigeration technique making possible wider oppor­ tunities for research and each new scientific discovery creating a need for a refrigerator with special features. In this book, Professor Walker has provided us with an excellent exposition of the achievements of this period, the fundamental principles involved, and a critical examination of the many different cryogenic systems which have led to a new era of low-level refrigeration. I feel fortunate to have had a part in the developments discussed in this book. During the early 1930s I constructed several rotary engines using leather vanes. Their performance was not good, but I was able to liquefy air. I had been impressed by the usefulness of leather cups in tire pumps and in Claude-type engines for air liquefaction. I was trying to find a way to avoid that part of the friction generated by a leather cup as a result of the radial force of the working gas on the cylindrical part of the cup. During the 1950s I built two efficient helium liquefiers in which essentially leather pistons were used.

of Part 2.- 8 Heat Exchangers in Cryocoolers.- Heat Exchangers in Cryocoolers.- Types of Heat Exchangers Used in Cryocoolers.- Heat Pipe.- Heat Exchangers for Very Low Temperature.- References.- 9 Some Aspects of Design.- Target Definition.- Reliability.- Coldfinger Design.- Balancing.- Bearings.- Seals.- Materials.- Cooling.- Electrial and Electronic Systems.- References.- 10 Practical Problems in Cryocooler Design and Operation.- Comparison of Cryocooler Types.- Design Considerations and System Trade-OfTs.- Special Problems Related to Cryocooler Operation.- References.- 11 Fundamentals of Alternate Cooling Systems.- Thermodynamic Considerations.- Entropies and Refrigeration Principles of Various Systems.- How Much Entropy is Enough?.- Alternate Means to Eliminating Mechanical Parts.- References.- 12 Very-Low-Temperature Cooling Systems.- He3 Refrigerators.- Pomeranchuk Cooling.- Magnetic Refrigerators.- References.- 13 Cryogenic Engineering and Cryocooler Development in the USSR.- Cryogenic Research Centers in the USSR.- Principal Cryogenic Publications in the USSR.- Properties of Substances at Low Temperatures.- Computing and Analyzing Cryogenic Processes and Cycles.- Expanders and Stirling Engines.- Heat Transfer Processes and Heat Exchangers.- Cryogenic Cooling Systems and Some Types of Cryogenic Equipment.- References.- 14 Cryogenic Engineering and Cryocooler Development in Japan.- Helium Liquefiers and Refrigerators.- Component Development.- Instability in Forced Cooling Systems.- Superconducting Magnetic Levitation of Trains (Maglev)..- Pulsed Refrigeration System.- Appendix 14.1.- References.- General Reading.- Government Reports.- Relevant Conferences.- Patents.- Appendix I Glossary of Terms for Cryocoolers and List of Organizations.- Appendix II OrganizationsHaving Substantial Interest in Cryocoolers and Cryocooler Manufacturing.- Organizations.- Manufacturers.- Appendix III Guide to the Cryogenic Engineering Literature Introduction.- Government Reports.- NTISearches.- Superintendent of Documents (SupDocs).- The Cryogenic Data Center.- Conference Proceedings.- Foreign Government Sources.- Open Literature Sources.- Advances in Cryogenic Engineering.- Cryogenics.- International Cryogenic Engineering Conference.- Applications of Cryogenic Technology.- International Institute of Refrigeration.- Low-Temperature Physics.- Books, Monographs, and Course Notes.- House Journals.- Name Index.