Cryogenics scale, both of which measure from absolute zero, rather than more usual scales such as Celsius or Fahrenheit, with their zeroes at arbitrary temperatures. The word "cryogenics" stems from Greek "κρύο (cryo)" – "cold" + "γονική (genic)" – "having to do with production". Cryogenic fluids with their boiling point in Kelvin Liquefied gases, such as liquid nitrogen and liquid helium, are used in many cryogenic applications. Liquid nitrogen is the most commonly used element in cryogenics and is legally purchasable around the world. Liquid helium is also commonly used and allows for the lowest attainable temperatures to be reached. These
Ship prefix in 1970. A United States Navy ship that is not in active commission does not hold the title of United States Ship with simply the name without prefix used before and after commissioned service. Vessels, such as yard and harbor craft that are not commissioned and "in service" are officially referred to by name or hull number without prefix. Military Sealift Command (MSC) civilian manned ships "in service" are given the prefix United States Naval Ship (USNS). Prior to commissioning, ships may be described as a pre-commissioning unit or PCU; for example, the uncommissioned has been described as the "pre-commissioning