In human history to date, only a few species of large animal have been domesticated. In approximate order of their earliest domestication these are: dog, sheep, goat, pig, ox, yak, reindeer, water buffalo, horse, donkey, llama, alpaca, Bactrian camel and Arabian camel.
For instance at sea level and standard weather (29.9 Hg) a gauge vacuum of -25.9 Hg is equivalent to an absolute pressure of 4 Hg. In other words, the vacuum gauges that read, for example, -25.9 Hg at full vacuum is actually reporting 4 Hg, or 136 mbar. That is still in the low vacuum range.
Gauge pressure is zero-referenced against ambient air pressure, so it is equal to absolute pressure minus atmospheric pressure. Absolute pressure is measured with reference to an absolute (and theoretical) vacuum. For example, an ordinary pressure gauge reading of zero does not mean there is no pressure; it simply means there is no pressure in excess of atmospheric pressure. Gauge Pressure = Total Pressure â 1 atm. The conversion factor that needs to be used in order to convert between gauge pressure and absolute pressure is atmospheric pressure. By adding a pressure of 1 atmosphere to an absolute pressure, the corresponding gauge pressure can be determined. Gauge pressure is measured with the standard atmospheric pressure as the baseline. Therefore, positive gauge pressures indicate that the pressure is above atmospheric pressure. Conversely, negative pressures indicate that the pressure is below atmospheric pressure.