Abstract: The invention can be used in a micropump for dispensing a pharmaceutical liquid, in an ink jet printer or similar devices, or in other applications for controlled pumping of a liquid through an opening in a barrier wall. A pair of electrodes is in electrical contact with a fluid confined behind a containing wall. Each electrode is connected to a source of different electrical potential. When current is conducted through the fluid between the electrodes, resistance heating in the fluid causes local boiling and thus the formation and expansion of a bubble within the fluid. The electrodes are disposed on either side of an opening in the wall, so that the bubble is formed on one side of the wall in close proximity to the opening. Fluid behavior is such that a fluid jet is formed when the bubble collapses in close proximity to the wall. This jet impacts the bubble in a direction toward the wall.

Abstract: The invention can be used in a micropump for dispensing a pharmaceutical liquid, in an ink jet printer or similar devices, or in other applications for controlled pumping of a liquid through an opening in a barrier wall. A pair of electrodes is in electrical contact with a fluid confined behind a containing wall. Each electrode is connected to a source of different electrical potential. When current is conducted through the fluid between the electrodes, resistance heating in the fluid causes local boiling and thus the formation and expansion of a bubble within the fluid. The electrodes are disposed on either side of an opening in the wall, so that the bubble is formed on one side of the wall in close proximity to the opening. Fluid behavior is such that a fluid jet is formed when the bubble collapses in close proximity to the wall. This jet impacts the bubble in a direction toward the wall.

Abstract: A micro-dimensional sensor measures the shear force, both in magnitude and direction, at the surface of a solid boundary as a fluid flows over that boundary. The sensor is a micro-mechanical capacitor-transducer system that includes a micro-dimensioned floating upper plate above a fixed lower plate supported on a substrate. The floating upper plate is mounted and held over the substrate by a number of zig-zap form supporting arms. The flow passing over the upper plate displaces the upper plate in a downstream direction, which results in a measurable change of the capacitance in the capacitor-transducer system. The direction and magnitude of the shear forces can then be obtained from the measured capacitance through specially designed circuitry.