found: Work cat.: Experimental determination of sodium vapor expansion characteristics with inert-gas-injection pressure-measuring technique, 1964:pp. 1-2 ("The application of alkali metals as working fluids for space power Rankine systems has emphasized the need for accurate and more extensive knowledge of their physical and thermodynamic properties. This knowledge is essential to evaluate properly the processes, such as vaporization, expansion, and condensation, that occur in this cycle. The vapor phase is of particular concern ...")
found: Webster's third new international dictionary of the English language, 1993("working substance - a usu. fluid substance that through changes of temperature, volume, and pressure is the means of carrying out thermodynamic processes or cycles (as in a heat engine or refrigerating machine")
found: Random House Webster's unabridged dictionary, 2001("working substance - a substance, usually a fluid, that undergoes changes in pressure, temperature, volume or form as part of a process for accomplishing work")
notfound: McGraw-Hill dictionary of scientific and technical terms, 2003;Academic Press dictionary of science and technology, 1992;Chambers dictionary of science and technology, 1999