Abstract: A technique of generating a flow from a gas. The technique includes the steps of selecting molecules from the gas on a nanoscopic or microscopic scale, and generating the flow from the selected molecules. The gas can be air. In one embodiment, the molecules are selected based on the direction of movement of the molecules. In another embodiment, the molecules are selected based on the velocities (i.e., direction and speed) of the molecules. Also, devices that implement the technique.

Abstract: A heteroscopic turbine with a Knudsen number of less than ten. In one embodiment, the heteroscopic turbine generates a flow from a gas. The turbine includes at least a moving surface and a plurality of turbine blades on or in said surface. Each of the blades has a height comparable to a mean free path distance that characterizes molecules in the gas, and the blades are spaced apart by a distance comparable to the mean free path distance. In operation, the surface moves such that the turbine blades pass through the gas at a speed comparable to the mean thermal velocity. In different embodiments, the turbine can perform filtering of molecules in the gas based on direction and/or speed (velocity). Also, techniques by which such a turbine operates.