Dan #Gelbart’s description of his 2010 #steam-engine. (Or maybe it's Tom Kimmel’s.) Includes a sort of zero-#TCE construction to keep the inside diameter of the cylinder constant: when the 440C stainless-steel cylinder expands, the graphite-filled #polyimide (Vespel) liner tries to expand even more, but can only do so toward the inside of the cylinder, thus counteracting the cylinder’s expansion. The piston itself is made of electroless-nickel-plated #Invar, which really seems like overkill, but whatever. The tabletop model reaches 10% efficiency.
on 02015-08-13Roderic Lakes’s #bibliography on composite #metamaterials that can have either negative or colossal thermal coefficients of expansion (#TCE) even if their components don’t. This is potentially useful for making nanometrically-precise #flexures without resorting to exotic materials like #Invar or maybe even metals.
on 02015-08-12