Cryogenic Engineering in Cryobiology
Studies of the behavior and storability of biological materials at temperatures below their freezing point have been subjected to many research activities concerned with long-term preservation. Although it is generally understood that the lower the temperature, the longer a desired characteristic or material property is maintained, the phenomena associated with the frozen state were not fully recognized until scientific curiosity extended beyond the limits of commercially available refrigeration equipment and entered the field of cryogenic temperatures. The selection of liquid nitrogen as a refrigerant with a temperature of -3200F was a logical step in opening the door for an intensive and practical investigation of events that take place not only in the transformation of a fluid substance into its solid frozen state, but particularly in phenomena associated with low temperatures. Aside from its temperature, liquid nitrogen has been found to be superior as a refrigerant because of its inertness as well as its fluid state. Although our knowledge of preservation at cryogenic temperatures is far from complete, many significant fundamental concepts have emerged.
Unable to display preview. Download preview PDF.