Cryogenic engineering therefore is involved with the design and development of low-temperature systems and components. In such activities the designer must be familiar with the properties of fluids used to achieve these low temperatures as well as the physical properties of components used to produce, maintain, and apply such temperatures. General Applications Low-Temperature Properties Refrigeration and Liquefaction Cryocoolers Separation and Purification of Gases Equipment Low-Temperature Insulations Storage and Transfer Systems Instrumentation Hazards of Cryogenic Systems