During 1990â2003, Pakistan sustained its historical lead as the second-most urbanized nation in South Asia with city dwellers making up 36% of its population. Furthermore, 50% of Pakistanis now reside in towns of 5,000 people or more.
Submarine Propulsion Systems. During World War II, most American submarines were powered by diesel-electric systems. This was a departure from earlier submarine power systems, which were direct drive types, little changed from the earliest boats. In this direct-drive power system, the diesel engine is directly connected to the propeller shaft.
Torpedo tubes used on German combat U-boats type II, VII, IX and XXIII during World War II were complex devices which allowed for setting the torpedo speed, depth and gyro angle, flooding the tube, launching the torpedo underwater or on the surface, draining the tube and reloading.