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.
Mechanical ventilation is the use of a mechanical device (machine) to inflate and deflate the lungs. Mechanical ventilation provides the force needed to deliver air to the lungs in a patient whose own ventilatory abilities are diminished or lost. Breathing requires the movement of air into and out of the lungs. This is normally accomplished by the diaphragm and chest muscles. A variety of medical conditions can impair the ability of these muscles to accomplish this task, including: muscular dystrophies.