The Prehistory of Jazz. The Africanization of American Music. An elderly black man sits astride a large cylindrical drum. Using his fingers and the edge of his hand, he jabs repeatedly at the drum head--which is around a foot in diameter and probably made from an animal skin--evoking a throbbing pulsation with rapid, sharp strokes.
nope, efficiency o fa machine cannot be greater than 100%...theoretically it shows sometime that efficiency of a machine can be 100%, but practically it cannot be possible as â¦ there is some loss of energy is always involved in different ways. Answer   In order for a machine to be 100% efficient, the amount of energy going into it has to be precisely equal to the energy the machine is putting out-with nothing lost.
equipment downtime, including the costs of lost operator wages, utilities and, more importantly, customer service; customer service or comfort, which is hard to measure but you sure do hear about it! Repair Or Replace? When a pump motor fails, managers face a repair-or-replace decision. Many companies use a 50-60 percent rule for repairs or replacement. If a repair cost is more than 50-60 percent of the cost of a new motor, it is not repaired. If the horsepower (hp) of the motor is less than a certain threshold, the motor is scrapped and replaced. A facility policy usually dictates this ratio.