Angle of repose and science, including: Angle of repose The angle of repose, or critical angle of repose, of a granular material is the steepest angle of descent or dip relative to the horizontal plane to which a material can be piled without slumping. At this angle, the material on the slope face is on the verge of sliding. The angle of repose can range from 0° to 90°. The morphology of the material affects the angle of repose; smooth, rounded sand grains cannot be piled as steeply as can rough, interlocking sands. The angle of repose can also be affected by additions
Nambu Type 90 Nambu Type 90 The Nambu Type 90 was a flare gun of Japanese origin and manufactured by Nambu. It was used by the Imperial Japanese Navy and came with two or three barrels. The Type 90 designation is from the last two digits of its year of adoption, which was 2590 (or 1930 AD) on the Japanese "Kōki" calendar. It first came with three barrels with just less than 6,000 were manufactured. The First Model (made in the early 1930s during peacetime) was highly polished and finished, while the Second Model (dating from the mid-1930s to the mid-1940s during wartime)