Stridsbåt 90 H(alv) (Strb 90 H; CB90) is a class of fast military assault craft used by several countries after being originally developed for the by . Its name means Combat Boat 90 Half; the 90 refers to the year of acceptance (1990) and Half refers to the fact that it can carry and deploy a half platoon of amphibious infantry (18 men) fully equipped. The CB90 is an e.
[pdf] Core drilling is a method of drilling that involves using a special drill bit and drill to remove a cylindrical core of material. This technique is often used in construction and other industries to create holes.
[pdf] In DTH drilling, the percussion mechanism – commonly called the hammer – is located directly above the drill bit. The drill pipes transmit the necessary feed force and rotation to the hammer and the bit, along with the fluid (air, water or drilling mud) used to actuate the hammer and flush the cuttings. The drill pipes are added to the drill string successively behind the hammer as the hole gets deeper.
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