This video shows why you cant always trust all information on the internet, as well as shows the basics of torque wrenches and a few oddball calculations you might run across when building custom things.
Underground mine ventilation. Underground mine ventilation provides a flow of air to the underground workings of a mine of sufficient volume to dilute and remove dust and noxious gases (typically NOx, SO2, methane, CO2 and CO) and to regulate temperature.
Jet ventilation, gas exchange. Definition. Jet ventilation can be performed via either high or low frequency means. High frequency jet ventilation (HFJV) is accomplished with specialized ventilators capable of producing the high pressure, low volume breaths necessary. Low frequency jet ventilation (LFJV), however, is usually accomplished with a manually triggered hand-held device.