Calories (15 °C, NBS 1939)
The 15 °C NBS 1939 calorie is the amount of energy required to raise the temperature of one gram of water by one degree Celsius, from 14.5 °C to 15.5 °C, at standard atmospheric pressure. This specific definition was established by the National Bureau of Standards (NBS) in 1939.
Kilotons (explosive energy)
A kiloton is a unit of measurement that quantifies the energy released in an explosion. It is the energy released by detonating 1,000 tons of TNT (trinitrotoluene). One kiloton is approximately equal to 4.184 × 1012 joules.