efficiency

efficiency.

1 In business and industry, see industrial management

The Rise of Factories

..... ; productivity.

2 In physics, seemachine; work.

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efficiency

 or mechanical efficiency

In mechanics, the measure of the effectiveness with which a system performs. It is stated as the ratio of a system's work output to its work input. The efficiency of a real system is always less than 1 because of friction between moving parts. A machine with an efficiency of 0.8 returns 80% of the work input as work output; the remaining 20% is used to overcome friction. In a theoretically frictionless, or ideal, machine, the work input and work output are equal, and the efficiency would be 1, or 100%.

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efficiency [ə′fish·ən·sē]

Abbreviated eff.

(chemistry)

In an ion-exchange system, a measurement of the effectiveness of a system expressed as the amount of regenerant required to remove a given unit of adsorbed material.

(engineering)

Measure of the degree of heat output per unit of fuel when all available oxidizable materials in the fuel have been burned.

Ratio of useful energy provided by a dynamic system to the energy supplied to it during a specific period of operation.

(nucleonics)

The probability that a count will be produced in a counter tube by a specified particle or quantum incident.

(physics)

The ratio, usually expressed as a percentage, of the useful power output to the power input of a device.

(statistics)

An estimator is more efficient than another if it has a smaller variance.

An experimental design is more efficient than another if the same level of precision can be obtained in less time or with less cost.

(thermodynamics)

The ratio of the work done by a heat engine to the heat energy absorbed by it. Also known as thermal efficiency.

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Efficiency

The ratio, expressed as a percentage, of the output to the input of power (energy or work per unit time). As is common in engineering, this concept is defined precisely and made measurable. Thus, a gear transmission is 97% efficient when the useful energy output is 97% of the input, the other 3% being lost as heat due to friction. A boiler is 75% efficient when its product (steam) contains 75% of the heat theoretically contained in the fuel consumed. All automobile engines have low efficiency (below 30%) because of the total energy content of fuel converted to heat; only a portion provides motive power, while a substantial amount is lost in radiator and car exhaust.