Description: Period of time during which an item performs its intended function, it includes all the time a machine is continuously running from start-up until it is shut down.; Name: ot
Description: passed time period after comissioning of a system, sub-system, component or piping; Name: Operating time 
Description: translation i of a pair of gears or a multiple gear pair is the ratio of the angle speed wa (or the speed na) of the first driving wheel to that of the last driven wheel wb (or nb); Name: Transmission ratio of the transmission