Abstract: A fluid ejection device may include a first channel having a first end and a second end, a first drop ejector along the first channel, a second channel having a first end and a second end, a second drop ejector along the second channel, a third channel extending between and connecting the first end of the first channel and the first end of the second channel, a fourth channel extending between and connecting the second end of the first channel and the second end of the second channel and a fifth channel extending between and connecting the third channel and the fourth channel.

Abstract: In one embodiment, a polymerase chain reaction (PCR) system includes a mixture chamber, a denature chamber, an annealing chamber, an extension chamber, and a product chamber, that are fluidically coupled to one another through a plurality of microfluidic channels. An inertial pump is associated with each microfluidic channel, and each inertial pump includes a fluid actuator integrated asymmetrically within its associated microfluidic channel. The fluid actuators are capable of selective activation to circulate fluid between the chambers in a controlled cycle.

Abstract: A thermal fluid-ejection mechanism includes a substrate having a top surface. A cavity formed within the substrate has one or more sidewalls and a floor. The angle of the sidewalls from the floor is greater than or equal to nominally ninety degrees. The thermal fluid-ejection mechanism includes a patterned conductive layer on one or more of the substrate's top surface and the cavity's sidewalls. The thermal fluid-ejection mechanism includes a patterned resistive layer on the sidewalls of the cavity. The patterned resistive layer is located over the patterned conductive layer where the patterned conductive layer is formed on the sidewalls of the cavity. The patterned resistive layer is formed as a heating resistor of the thermal-fluid ejection mechanism. The conductive layer is formed as a conductor of the thermal-fluid ejection mechanism, to permit electrical activation of the heating resistor to cause fluid to be ejected from the thermal fluid-ejection mechanism.