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  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    One part per billion (ppb) denotes one part per 1,000,000,000 (10 9) parts, and a value of 10 −9. This is equivalent to about three seconds out of a century. One part per trillion (ppt) denotes one part per 1,000,000,000,000 (10 12) parts, and a value of 10 −12. This is equivalent to about thirty seconds out of every million years.

  3. Failure rate - Wikipedia

    en.wikipedia.org/wiki/Failure_rate

    The mean time between failures (MTBF, /) is often reported instead of the failure rate, as numbers such as "2,000 hours" are more intuitive than numbers such as "0.0005 per hour". However, this is only valid if the failure rate λ ( t ) {\displaystyle \lambda (t)} is actually constant over time, such as within the flat region of the bathtub curve.

  4. Piece work - Wikipedia

    en.wikipedia.org/wiki/Piece_work

    The fair rate is the amount that allows an average worker to be paid the minimum wage per hour if they work at an average rate. This must be calculated in a set way, a control trial is run to determine the average items produced by equivalent workers, this is divided by 1.2 to reach the agreed average figure, and the fair rate is set to ensure ...

  5. Overall equipment effectiveness - Wikipedia

    en.wikipedia.org/wiki/Overall_equipment...

    Total Time: 8-hour shift or 28,800 seconds, producing 14,400 parts, or one part every 2 seconds. Fastest possible cycle time is 1.5 seconds, hence only 21,600 seconds would have been needed to produce the 14,400 parts. The remaining 7,200 seconds or 2 hours were lost. The OEE is now the 21,600 seconds divided by 28,800 seconds (same as minimal ...

  6. Man-hour - Wikipedia

    en.wikipedia.org/wiki/Man-hour

    A man-hour or human-hour is the amount of work performed by the average worker in one hour. [1] [2] It is used for estimation of the total amount of uninterrupted labor required to perform a task. For example, researching and writing a college paper might require eighty man-hours, while preparing a family banquet from scratch might require ten ...

  7. Horsepower - Wikipedia

    en.wikipedia.org/wiki/Horsepower

    The average steam consumption of those engines (per output horsepower) was determined to be the evaporation of 30 pounds (14 kg) of water per hour, based on feed water at 100 °F (38 °C), and saturated steam generated at 70 psi (480 kPa). This original definition is equivalent to a boiler heat output of 33,485 Btu/h (9.813 kW).

  8. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    1 volume percent = 10,000 ppmv (i.e., parts per million by volume) with a million being defined as 10 6. Care must be taken with the concentrations expressed as ppbv to differentiate between the British billion which is 10 12 and the USA billion which is 10 9 (also referred to as the long scale and short scale billion, respectively).

  9. Air changes per hour - Wikipedia

    en.wikipedia.org/wiki/Air_changes_per_hour

    Air changes per hour, abbreviated ACPH or ACH, or air change rate is the number of times that the total air volume in a room or space is completely removed and replaced in an hour. If the air in the space is either uniform or perfectly mixed, air changes per hour is a measure of how many times the air within a defined space is replaced each hour.