- Quality (physics)
In physics, quality has several different meanings.
Thermodynamics
The quality of a fluid is the percentage of
mass that isvapor ; i.e. saturated vapor has a "quality" of 100%, and saturated liquid has a "quality" of 0%. For instance, in analysis of theRankine cycle the quality of a multi-phaseworking fluid would be understood to imply this definition.Another definition used by chemical engineers defines quality (q) of a fluid as the fraction that is saturated liquid. [cite book|last=Wankat|first=Philip C.|title=Equilibrium Staged Separations|publisher=Prentice Hall|place=Upper Saddle River, New Jersey|year=1988|pages=119-121|isbn=0135009685] By this definition, a saturated liquid has q = 1. A saturated vapor has q = 0. A sub-cooled liquid will have q < 0 while a superheated vapor has q > 1. [Perry's Chemical Engineers' Handbook (7th Edition), p 13-29]
An alternate meaning of quality of heat may be used to describe the "availability" of thermal energy as dictated by the
second law of thermodynamics . Also seeexergy efficiency .Harmonics
In response theory, the quality of an excited system is related to the number of
excitation frequencies to which it can respond. In the case of a homogeneous,isotropic system, the quality is proportional to the full width at half maximum.This sense of the phrase is the primogenitor of the usage of the word in
music theory . In music theory, quality is the number ofharmonics of afundamental frequency of an instrument (the higher the quality, the richer thesound ).References
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