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  2. High-temperature operating life - Wikipedia

    en.wikipedia.org/wiki/High-temperature_operating...

    Assuming Tj = 125 °C, commonly used checkpoints are after 48, 168, 500 and 1,000 hours. Different checkpoints for different temperatures can be calculated by using the Arrhenius equation. For example, with an activation energy of 0.7e V, T j of 135 °C and T use of 55 °C the equivalent checkpoints will be at 29, 102, 303 and 606 hours.

  3. Failure rate - Wikipedia

    en.wikipedia.org/wiki/Failure_rate

    The Failures In Time (FIT) rate of a device is the number of failures that can be expected in one billion (10 9) device-hours of operation [17] (e.g. 1,000 devices for 1,000,000 hours, or 1,000,000 devices for 1,000 hours each, or some other combination).

  4. Heating degree day - Wikipedia

    en.wikipedia.org/wiki/Heating_degree_day

    As total energy consumption is in kilowatt hours and heating degree days are [no. days×degrees] we must convert watts per kelvin into kilowatt hours per degree per day by dividing by 1000 (to convert watts to kilowatts), and multiplying by 24 hours in a day (1 kW = 1 kW⋅h/h).

  5. Decimal time - Wikipedia

    en.wikipedia.org/wiki/Decimal_time

    The time of day is sometimes represented as a decimal fraction of a day in science and computers. Standard 24-hour time is converted into a fractional day by dividing the number of hours elapsed since midnight by 24 to make a decimal fraction. Thus, midnight is 0.0 day, noon is 0.5 d, etc., which can be added to any type of date, including (all ...

  6. Mean time between failures - Wikipedia

    en.wikipedia.org/wiki/Mean_time_between_failures

    The first system fails after 100 hours, the second after 120 hours and the third after 130 hours. The MTBF of the systems is the average of the three failure times, which is 116.667 hours. If the systems were non-repairable, then their MTTF would be 116.667 hours.

  7. Why some parents are committing to spending 1,000 hours ... - AOL

    www.aol.com/lifestyle/why-parents-committing...

    Kids between 8 and 18 spend an average of 7.5 hours in front of a screen — every day, according to the Centers for Disease Control and Prevention. It’s probably not the most shocking statistic ...

  8. Seasonal energy efficiency ratio - Wikipedia

    en.wikipedia.org/wiki/Seasonal_energy_efficiency...

    The unit is operated 120 days each year for 8 hours per day (960 hours per year), and the electric energy cost is $0.10 per kilowatt-hour. What is its annual cost of operation in terms of electric energy? First, we convert tons of cooling to BTU/h: (4 tons) × (12,000 (BTU/h)/ton) = 48,000 BTU/h. The annual cost of the electric energy is:

  9. 7 Easy Ways to Make $1,000 in 30 Days - AOL

    www.aol.com/finance/7-easy-ways-1-000-180019786.html

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