Decompression Any of a variety of maladies resulting either primarily or
sickness secondary from the formation of nitrogen bubbles in tis-
sues or body fluids, as a result of inadequately controlled
decompression. Commonly called “bends” or “DCS”.
Dive series A group of repetitive dives between which the IQ-400 indi-
cates some nitrogen loading is present. When nitrogen
loading reaches zero the IQ-400 deactivates.
Dive time Elapsed time between leaving the surface to descend, and
returning to the surface at the end of a dive.
Half-time After a change in ambient pressure, the amount of time
required for the partial pressure of nitrogen in a theoretical
compartment to go half-way from its previous value to sat-
uration at the new ambient pressure.
Multi-level dive A single or repetitive dive that includes time spent at vari-
ous depths and whose no-decompression limits are not
determined solely by the maximum depth attained.
No-decompression The maximum amount of time a diver may remain at a
time particular depth without having to make decompression
stops or remain below a ceiling during the subsequent
ascent.
No-decompression Any dive which permits a direct, uninterrupted ascent to
dive the surface at any time.
NO DEC TIME Abbreviation for no-decompression time limit.
Repetitive dive Any dive whose no-decompression time limits are affected
by residual nitrogen absorbed during previous dives.
Residual nitrogen The amount of excess nitrogen remaining in a diver after
one or more dives.
SURF TIME Abbreviation for surface interval time.
Surface interval Elapsed time between surfacing from a dive and beginning
time a descent for the subsequent repetitive dive.
Tissue group Theoretical concept used to model bodily tissues for the
construction of decompression tables or calculations.
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