Anemometer in pressure of the two lines. The measurement devices can be manometers, pressure transducers, or analog chart recorders. In the tube anemometer the dynamic pressure is actually being measured, although the scale is usually graduated as a velocity scale. If the actual air density differs from the calibration value, due to differing temperature, elevation or barometric pressure, a correction is required to obtain the actual wind speed. Approximately 1.5% (1.6% above 6,000 feet) should be added to the velocity recorded by a tube anemometer for each 1000 ft (5% for each kilometer) above sea-level. At airports, it is essential to
Signed measure finite signed measure is given by for all "A" in Σ. This signed measure takes only finite values. To allow it to take +∞ as a value, one needs to replace the assumption about "f" being absolutely integrable with the more relaxed condition where "f"("x") = max(−"f"("x"), 0) is the negative part of "f". What follows are two results which will imply that an extended signed measure is the difference of two nonnegative measures, and a finite signed measure is the difference of two finite non-negative measures. The Hahn decomposition theorem states that given a signed measure μ, there exist