Some tiny or nano heat engines

World's 'smallest steam engine' built in Germany

- Themicroscopic model was based on a 195-year-old design by the inventor Robert Stirling.

"Nowadays everybody is trying to make things smaller - electronic circuits and mechanical devices get smaller and smaller - so we thought why not try to investigate this basic process at a micro-scale."

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Tiny heat engine may be world's smallest

"The basis of the heat engine is a solid piece of micrometer-sized silicon crystal that has two short beams jutting out from one end. When 1.2 milliamps of DC current is applied to one of the beams, the beam heats up as a consequence of its electrical resistance, and expands due to thermal expansion."

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Graphene enables world's smallest heat engine, may power future nano robots

"The new nano-engine is made of graphene and weakly chemisorbed ClF3 molecules. The CIF3 molecules are used as actuators. The engine uses a laser light beam as the “ignition plug” - when the CIF3 molecules are exposed to the laser (532 nm wavelength) they sublimate - which expand the volume at the interface between the graphene and the substrate it is grown on. This generates a high pressure (around 23 MPa) and creates a "dome-like blister". The expansion (and later contraction when the laser is turned off) is equivalent to the motion of a piston in an internal combustion engine. The blister size can be controlled by changing the laser power."

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Single atom engine

"The new device makes far too little power to supply us with energy anytime soon. But Jacob Taylor, a physicist at the National Institute of Standards and Technology in Gaithersburg, Maryland, says it provides experimental data for "a quiet revolution” in statistical physics, the study of how heat flows both in microscopic systems and on the scale of everyday life."

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A quantum-dot heat engine operating close to the thermodynamic efficiency limits

"PE heat engine based on a quantum dot (QD) embedded into a semiconductor nanowire."

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