Spray systems and control systems for use with spray systems are provided. A method of detecting fluid flow through a nozzle coupled in fluid communication with a solenoid valve including a solenoid coil and a poppet is provided. The method generally includes (1) dispensing fluid through the solenoid valve and the nozzle, (2) de-energizing the solenoid coil to close the solenoid valve and control a fluid flow through the nozzle, (3) determining a closing time of the solenoid valve based on a signal from a poppet measuring device, and (4) determining a fluid flow value based on a time delay between the de-energizing the solenoid coil and the closing time.

A computer apparatus and method to determine aircraft fuel mileage performance. The computer apparatus including a memory and a processor disposed in communication with the memory and configured to issue a plurality of instructions stored in the memory. The instructions issue signals to receive real-time aircraft data during aircraft flight and process the real-time data to determine real-time aircraft mass data. A calculation is performed to determine the real-time fuel mileage performance for the aircraft based upon determined real-time aircraft mass data.

This fuel calculation device comprises: a remaining fuel amount calculation unit that periodically calculates and stores an approximate value of the remaining fuel amount on the basis of the measurement value of the remaining fuel amount remaining in a fuel container, and the fuel flow rate of fuel supplied from the fuel container; a failure determination unit that determines whether a remaining fuel amount meter that outputs the measurement value of the remaining fuel amount has failed; and a display control unit that controls so as to display the measurement value of the remaining fuel amount when the remaining fuel amount meter has not failed, and to display the approximate value of the remaining fuel amount when the remaining fuel amount meter has failed.

A method for estimating a volume of liquid output from an electric pump during an operation period of the electric pump, the method comprising: determining a current delay of the pump, wherein the current delay is a period between a first time corresponding to a first current drawn by the pump, and a second time corresponding to a second current drawn by the pump; and generating, based on the current delay, an estimate of the volume of liquid output from the electric pump during the operation period.

A method includes receiving, by a processor of a dialysis machine, a dialysate flow rate, a bicarbonate setting value, a signal from a pressure sensor configured to measure a pressure within a container, and a signal indicating a state of a fill valve; determining, based on the signal received from the pressure sensor and the state of the fill valve, fill parameters; determining a volume of the container based on at least two of the fill parameters; determining a depletion time in which the concentrate will be depleted from the container based on the volume of the container, the dialysate flow rate, and the bicarbonate setting value; determining, based on the depletion time, an amount of time remaining before the concentrate will be depleted from the container; and causing the dialysis machine to indicate the amount of time remaining before the concentrate will be depleted from the container.