Rubber Band Heat Engines Do Violate the Second Law of Thermodynamics

"Stretchy Science: A Rubber Band Heat Engine. Learn how a rubber band can turn heat into mechanical work with this simple activity. [...] Your blow dryer essentially turned your rubber band into a heat engine - a machine that turns thermal energy into mechanical work." https://www.scientificamerican.com/a...ber-band-heat/

http://readingpenrose.files.wordpres...and-engine.gif

These are non-isothermal heat engines - they do not violate the second law of thermodynamics. (At least it would be difficult, if not impossible, to calculate their maximal efficiency and compare it with the efficiency of the Carnot engine.)

However there are ISOTHERMAL analogs which almost obviously violate the second law of thermodynamics (one should only evaluate the work involved in a quasi-static cycle):

http://www.gsjournal.net/old/valev/val3.gif

A. KATCHALSKY, POLYELECTROLYTES AND THEIR BIOLOGICAL INTERACTIONS, p. 15, Figure 4: "Polyacid gel in sodium hydroxide solution: expanded. Polyacid gel in acid solution: contracted; weight is lifted."
https://www.ncbi.nlm.nih.gov/pmc/art...00645-0017.pdf

"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." http://www.google.com/patents/US5520672

Pentcho Valev