Description: The ratio of the output variable to the rate of change of the input variable; Name: differential factor
Description: for a derivative element, the quotient of the value of the output variable to the value of the time derivative of the input variable; Name: derivative action coefficient
Description: amount of the absolute value of the total head above the head, equivalent to the vapour pressure of the liquid at the particular temperature, with reference to the NPSH datum plane; Name: net positive suction head