Misleading education: "A NECESSARY component of a heat engine, then, is that TWO TEMPERATURES ARE INVOLVED. At one stage the system is heated, at another it is cooled." http://physics.bu.edu/~duffy/py105/Heatengines.html
"The Kelvin–Planck statement of the second law of thermodynamics states that no heat engine can produce a net amount of work while exchanging heat with a single reservoir only." https://anirudhbhaskaran.weebly.com/uploads/2/1/6/7/21674002/ch6.pdf
The second law of thermodynamics would be long forgotten if scientists were not misled into believing that one-temperature (single-reservoir) heat engines do not exist. Actually, such heat engines are commonplace. Just an example:
"When the pH is lowered (that is, on raising the chemical potential, μ, of the protons present) at the isothermal condition of 37°C, these matrices can exert forces, f, sufficient to lift weights that are a thousand times their dry weight." https://patentimages.storage.googleapis.com/12/1d/09/0fb416e99018cf/US5393602.pdf
This is the upper picture here:
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The contractile polymers that "lift weights that are a thousand times their dry weight" are described here: https://pubs.acs.org/doi/pdf/10.1021/jp972167t. One can heat and then cool them (TWO-TEMPERATURE or TWO-RESERVOIR heat engine), but one can alternatively decrease and then increase the pH in the system (ONE-TEMPERATURE or SINGLE-RESERVOIR heat engine).
Pentcho Valev https://twitter.com/pentcho_valev
