Background Cardiac implantable electric devices are commonly used to treat heart failure. Little is known about temporal and geographic variation in use of cardiac resynchronization therapy (CRT) devices in usual care settings.
A hammer drill, also known as a rotary hammer, roto-drill or hammering drill, (see also rotary drill) is a rotary drill with a hammering action. The hammering action provides a short, rapid hammer thrust to pulverize relatively brittle material and provide quicker drilling with less effort.
Water hammer is a complex process of formation of elastic deformations in a liquid and their propagation through a tube. If the pressure rise is very great, the impact can cause damage. Safety devices (equalizing reservoirs, air domes, valves, and so on) are installed in pipelines to prevent such damage.