A method for assembling a gas turbine engine assembly includes providing a core gas turbine engine including a high-pressure compressor, a combustor, and a high-pressure turbine, and coupling a low-pressure compressor between the core gas turbine engine and a motor such that the low-pressure compressor is driven only by the motor. The invention further provides a system and method for batch signal metering that provides feedback on the amount of fluid that has been dispensed. 01 to about 2 wt % of a fluorine compound, from about 1 to about 10 wt % of an inorganic acid, from about 0. Points in the region may be weighted according to their color distance relative to the seed color, where the color distance can also take into account alpha values.