Gray (unit) Gray (unit) The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI). It is defined as the absorption of one joule of radiation energy per kilogram of matter. It is used as a unit of the radiation quantity absorbed dose which measures the energy deposited in a unit mass at a certain position, and of the radiation quantity kerma, which is the amount of energy that is transferred from photons to electrons per unit mass at a certain position. The corresponding cgs unit to the gray is the rad (equivalent to
Work of breathing narcotic effects. Standards for these conditions exist and to make useful comparisons between breathing apparatus they must be tested to the same standard. Factors which influence the work of breathing of an underwater breathing apparatus include density and viscosity of the gas, flow rates, cracking pressure (the pressure differential required to open the demand valve), and back pressure over exhaust valves. The ANSTI machine is used for automated testing of underwater breathing apparatus. Work of breathing Work of breathing (WOB) is the energy expended to inhale and exhale a breathing gas. It is usually expressed as work per unit volume,