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.
If this closed volume is bound by the surface of a vacuum cup and a workpiece, atmospheric pressure will press the two objects together. The amount of holding force depends on the surface area shared by the two objects and the vacuum level.he difference in height between the two levels indicates the vacuum level. Manometers can measure vacuum directly to 29.25 in.-Hg. An absolute pressure gauge shows the pressure above a theoretical perfect vacuum. It has the same U-shape as the manometer, but one leg of the absolute pressure gauge is sealed, Figure 3.