Q factor — 1. The pressure coefficient of the un- 

 protected thermometer expressed in °C. (67) 

 2. See quality factor. 



quadrature — Tlie position in the phase cycle when 

 the two principal tide producing bodies (moon 

 and sun) are nearly at a right angle to the earth ; 

 the moon is then in quadrature in its first quarter 

 or last quarter. {See figure for tide cycle.) 



quadrature spectrum — The spectral decomposi- 

 tion of the 90-degree out-of -phase components of 

 the covariance of two functions of time. 



qualitative plankton sampler — A sampler that 

 sieves out orgaiiisms from the water but does not 

 measure the volume of water filtered. 



quality factor — (also called Q factor). The 

 quantity, ^, is a measure of the sharpness of 

 resonance of frequency selectivity of a resonant 

 vibrator system having a single degree of free- 

 dom, either mechanical or electrical. A high 

 value for Q means that the resonance is sharp, 

 that is, any small change in the frequency of the 

 excitation causes a large drop in the response of 

 the system. (3) 



quantitative plankton sampler — A sampler that 

 sieves out organisms from the water and meas- 

 ures the volume of water filtered. 



quantity of radiant energy — The quantity of 

 energy transferred by radiation. Unit of 

 measurement is in Joules or ergs. ( 8 ) 



quar ice — A Labrador term for ice formed in 

 spring from melt water draining on to a beach, 

 ice foot, or fast ice, where it refreezes. (8) 

 Rare. 



quarter-diurnal tide — The tide resulting from 

 the distortion of the normal tide in shallow wa- 



ter, with four high water and four low wa- 

 ters during one day. (32) 



quartering sea — See beam sea. 



quartz — A fonn of silicon dioxide. The most 

 common inorganic constituent of marine sedi- 

 ments. (9) 



quasi-synoptic — Nearly simultaneous environ- 

 mental measurements. 



quenching — The great reduction in underwater 

 sound transmission or reception resulting from 

 absorption and scattering of sound energy by 

 air bubbles entrapped around the sonar dome. 

 Roll and pitch of the ship in relatively rough 

 water is the primary cause of air bubble 

 entrapment. 



quench/ping ratio — In sound ranging, a meas- 

 ure of the somid lost from quenching. Based 

 on the ratio of the number of echoes received 

 (quench) to the number of pulses emitted 

 (ping). 



quick — Sediment of clay to sand size whicli by 

 absorption or admixture of water becomes loose, 

 incoherent, unstable, liquid or semiliquid, and 

 capable of flowing easily under load or by force 

 of gravity. Quick clay of glacial or marine 

 origin becames metastable or "quick" as a result 

 of the leacliing out of salts and their replace- 

 ment by water. Any shock may cause a re- 

 orientation of the grain structure with squeezing 

 out of the interstitial water and conversion of 

 the clay into a plastic or semiliquid state in 

 which the clay will flow and fail under load. 



quick clay — See quick. 



quicksand — See quick. 



Q wave — See Love wave. 



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