Microfluidic stepwise-waveform regulator driven by constant pressure

This paper reports a stepwise-waveform (SW) regulator that stepwise increases or decreases pressure without any dynamic controllers but only with constant water-head pressure. The SW regulator consists of a microfluidic oscillator and a diode pump, and sequentially converts constant pressure to pulsatile and then to stepwise pressure. The pressure increment and duration time were independently tuned in the range of 215-431 Pa and 26-181 s, respectively. With connection of an additional valve to the regulator, the SW regulator generated SWs of flow rate, shear stress, and chemical concentration.