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oxygen microphone
oxygen microphone Microphone fitted to oxygen mask
(probably arch.).
OY Option Year.
OY, Oy Lateral axis about which aircraft pitches;
confusingly, some authories now make this the roll
[longtitudinal] axis.
OYM Optional yield management.
OZ, Oz Vertical axis about which aircraft yaws.
oz Ounce, 1 /16 lb = 28.35 g.
OZB Civil aviation directory, under Ministry of Works
(Austria).
ozonosphere
ozone O 3 , allotropic form of oxygen present in minute
quantities in air, liquid fainly bluish, very reactive, BPt
–182.97°C.
ozone layer See ozonosphere.
ozonosphere Layer of upper atmosphere, roughly at
20–40 km altitude, where ozone concentration is much
higher than at SL and ozone plays major role in establishing
radiation balance.
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