Diesel engines could drive them at nine knots on the surface, but once submerged, large batteries permitted their electric motors to drive them underwater at the high speed of 15 knots for two hours. (Ten knots was a common speed for submerged submarines until after World War II.) Thus, ...
There are many different types of accelerometers. The mechanical ones are a bit like scaled-down versions of passengers sitting in cars shifting back and forth as forces act on them. They have something like a mass attached to a spring suspended inside an outer casing. When they accelerate, ...
Electric locomotives, introduced in 1887, rapidly became popular, but mules and horses were still working in some mines as late as the 1940s. Mechanized loading The loading by hand of broken coal into railcars was made obsolete early in the 20th century by mobile loaders. The Stanley Header...
Open-flame illumination, however, was a much more common cause of explosions until the introduction of theDavy safety lamp(about 1815), in which the flame is enclosed in a double layer of wire gauze that prevents ignition of flammable gases in the air of the mine. Presence of strong air ...
Open-flame illumination, however, was a much more common cause of explosions until the introduction of the Davy safety lamp (about 1815), in which the flame is enclosed in a double layer of wire gauze that prevents ignition of flammable gases in the air of the mine. Presence of strong air...