Clifford Truesdell: Thermodynamics Is a Dismal Swamp of Obscurity
(trop ancien pour répondre)
Pentcho Valev
2017-08-01 07:03:53 UTC
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Clifford Truesdell, The Tragicomical History of Thermodynamics, 1822-1854, p. 6: "Finally, I confess to a heartfelt hope - very slender but tough - that even some thermodynamicists of the old tribe will study this book, master the contents, and so share in my discovery: Thermodynamics need never have been the Dismal Swamp of Obscurity that from the first it was and that today in common instruction it is; in consequence, it need not so remain." [...] p. 333: "Clausius' verbal statement of the "Second Law" makes no sense, for "some other change connected therewith" introduces two new and unexplained concepts: "other change" and "connection" of changes. Neither of these finds any place in Clausius' formal structure. All that remains is a Mosaic prohibition. A century of philosophers and journalists have acclaimed this commandment; a century of mathematicians have shuddered and averted their eyes from the unclean." https://www.amazon.com/Tragicomical-Thermodynamics-1822-1854-Mathematics-Physical/dp/1461394465

Thermodynamicists may disagree with Truesdell but it would be difficult to ignore the view of Jos Uffink, arguably the best expert on the foundations of thermodynamics:

Jos Uffink, Bluff your way in the Second Law of Thermodynamics: "I therefore argue for the view that the second law has nothing to do with the arrow of time. [...] Before one can claim that acquaintance with the Second Law is as indispensable to a cultural education as Macbeth or Hamlet, it should obviously be clear what this law states. This question is surprisingly difficult. The Second Law made its appearance in physics around 1850, but a half century later it was already surrounded by so much confusion that the British Association for the Advancement of Science decided to appoint a special committee with the task of providing clarity about the meaning of this law. However, its final report (Bryan 1891) did not settle the issue. Half a century later, the physicist/philosopher Bridgman still complained that there are almost as many formulations of the second law as there have been discussions of it. And even today, the Second Law remains so obscure that it continues to attract new efforts at clarification." http://philsci-archive.pitt.edu/313/1/engtot.pdf

So Clausius' statement of the second law "makes no sense"; "the second law has nothing to do with the arrow of time"; "the Second Law remains so obscure that it continues to attract new efforts at clarification"... What the hell is going on? Is it possible that in the "Dismal Swamp of Obscurity" commonplace mechanisms able to convert ambient heat into work are forbidden, derided, anathematized etc.? It is not only possible, it is the case:

Here is water placed in an electric field. Vigorous cyclic motion can be seen, obviously able to produce unlimited amount of work at the expense of heat absorbed from the surroundings (no other source of energy is conceivable - no electric current passes through the system). Also, heat flows from cold (surroundings) to hot (the bridge) - the heat accumulated in the bridge can come from nowhere else:

Floating Water Bridge - Wasserfadden - Physics Experiment

"The Formation of the Floating Water Bridge including electric breakdowns"

"One thing that the researchers did notice is that the water in the bridge tends to get quite hot as the bridge forms – in some cases exceeding 50 degrees Celsius (122 degrees Fahrenheit). According to Benmore, there have been cases in which boiling floating water bridges have formed."

Floating water bridge / thermography

Physicists watch the videos - not one could think of a reason why the second law of thermodynamics should be questioned. Actually there is no thought at all in physicists' heads at that moment:

"Crimestop means the faculty of stopping short, as though by instinct, at the threshold of any dangerous thought. It includes the power of not grasping analogies, of failing to perceive logical errors, of misunderstanding the simplest arguments if they are inimical to Ingsoc, and of being bored or repelled by any train of thought which is capable of leading in a heretical direction. Crimestop, in short, means protective stupidity."

Water in an electric field again:

"However, in experiments in which a capacitor is submerged in a dielectric liquid the force per unit area exerted by one plate on another is observed to decrease... [...] This apparent paradox can be explained by taking into account the difference in liquid pressure in the field filled space between the plates and the field free region outside the capacitor."

We have a high pressure between the plates and a lower pressure outside the capacitor so if we punch a small hole in one of the plates, there will be an ETERNAL FLOW through the hole, from inside (between the plates) to outside. That is, we will have a SYSTEM IN DYNAMIC EQUILIBRIUM. The eternal flow can be harnessed to do work, in violation of the second law of thermodynamics.

If the plates of the capacitor are only partially immersed, the pressure between them pushes the liquid upwards:

I. Brevik, Fluids in electric and magnetic fields: Pressure variation and stability, Can. J . Phys. (1982): "Fig. 1. Two charged condenser plates partly immersed in a dielectric liquid. [...] Fig. 2. The hydrostatic pressure variation from point 1 to point 5 in Fig. 1."

Rise in Liquid Level Between Plates of a Capacitor

Liquid Dielectric Capacitor

Chapter 11.6.2: Force on a liquid dielectric

But the rising dielectric liquid can do useful work, e.g. by lifting some floating weight, and the crucial question is: At the expense of what energy is the work done? Since, by switching the field on and off, we do no work on the system, the energy supplier can only be the ambient heat. That is, the system can cyclically lift floating weights at the expense of heat absorbed from the surroundings, in violation of the second law of thermodynamics.

Pentcho Valev
Pentcho Valev
2017-08-02 08:08:18 UTC
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"Scientists have developed a special heat-sensitive polymer that's capable of lifting 1,000 times its own weight and quickly contracting back to its original shape. The new material could eventually be used in everything from medical devices that work according to your body heat, to clothes that automatically shrink to provide a snug fit. The fact that the heat of a human body is enough to get the polymer to react is what makes it such a potentially useful material." http://www.sciencealert.com/this-new-shape-shifting-polymer-can-lift-1-000-times-its-own-weight

When the temperature varies the violation of the second law of thermodynamics is difficult to prove but still the suspicion should be strong: We have small temperature changes and a great amount of work produced. Similar polymers can work isothermally (pH changes replace temperature changes) - in isothermal conditions the second law is almost obviously violated:

"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

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." http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1367611/pdf/biophysj00645-0017.pdf

The work-producing cycle is easy to imagine. The experimentalist adds hydrogen ions to the system - the polymer contracts and lifts a weight. The experimentalist removes the same amount of hydrogen ions from the system - the polymer resumes its initial state and a new cycle can begin:

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The second law of thermodynamics is violated unless the experimentalist, in adding hydrogen ions to the system and then removing them, does (wastes) more work than the work gained as the polymer lifts the weight. However electrochemists know that, if both adding and removing are performed quasi-statically, the net work involved is (almost) zero - the experimentalist gains work if the hydrogen ions are transported from a high to a low concentration but then loses the same amount of work in the backward transport. One can imagine that the polymer is placed in one of the half-cells of a concentration cell:

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Second-law-violating systems of this kind are commonplace:

"pH sensitive or pH responsive polymers are materials which will respond to the changes in the pH of the surrounding medium by varying their dimensions. Such materials increase its size (swell) or collapse depending on the pH of their environment. [...] Although many sources talk about synthetic pH sensitive polymers, natural polymers can also display pH-responsive behavior." https://en.wikipedia.org/wiki/PH-sensitive_polymers

Pentcho Valev
Pentcho Valev
2017-08-02 16:15:23 UTC
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The following argument is obviously valid:

If there is no evidence that the entropy is a state function for ANY system, then the concept of entropy is not even wrong.

Is there any evidence that the entropy is a state function for ANY system? No. If you define the entropy S as a quantity that obeys the equation dS=dQrev/T, you will find that, so defined, the entropy is a state function FOR AN IDEAL GAS. Clausius was very impressed by this statefunctionness and decided to prove that the entropy (so defined) is a state function for ANY system. So "Entropy is a state function" became a fundamental theorem in thermodynamics. Clausius deduced it from the assumption that any cycle can be disintegrated into small Carnot cycles, and nowadays this deduction remains the only justification of "Entropy is a state function":

"Carnot Cycles: S is a State Function. Any reversible cycle can be thought of as a collection of Carnot cycles - this approximation becomes exact as cycles become infinitesimal. Entropy change around an individual cycle is zero. Sum of entropy changes over all cycles is zero." http://mutuslab.cs.uwindsor.ca/schurko/introphyschem/lectures/240_l10.pdf

"Entropy Changes in Arbitrary Cycles. What if we have a process which occurs in a cycle other than the Carnot cycle, e.g., the cycle depicted in Fig. 3. If entropy is a state function, cyclic integral of dS = 0, no matter what the nature of the cycle. In order to see that this is true, break up the cycle into sub-cycles, each of which is a Carnot cycle, as shown in Fig. 3. If we apply Eq. (7) to each piece, and add the results, we get zero for the sum." http://ronispc.chem.mcgill.ca/ronis/chem213/hnd8.pdf

The assumption on which "Entropy is a state function" is based - that any cycle can be subdivided into small Carnot cycles - is obviously false. An isothermal cycle CANNOT be subdivided into small Carnot cycles. A cycle involving the action of conservative forces CANNOT be subdivided into small Carnot cycles.

Conclusion: The belief that the entropy is a state function is totally unjustified. Any time scientists use the term "entropy", they don't know what they are talking about.

"My greatest concern was what to call it. I thought of calling it 'information', but the word was overly used, so I decided to call it 'uncertainty'. When I discussed it with John von Neumann, he had a better idea. Von Neumann told me, 'You should call it entropy, for two reasons: In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, nobody knows what entropy really is, so in a debate you will always have the advantage." https://en.wikipedia.org/wiki/History_of_entropy

Jos Uffink, Bluff your way in the Second Law of Thermodynamics: "I therefore argue for the view that the second law has nothing to do with the arrow of time. [...] This summary leads to the question whether it is fruitful to see irreversibility or time-asymmetry as the essence of the second law. Is it not more straightforward, in view of the unargued statements of Kelvin, the bold claims of Clausius and the strained attempts of Planck, to give up this idea? I believe that Ehrenfest-Afanassjewa was right in her verdict that the discussion about the arrow of time as expressed in the second law of the thermodynamics is actually a RED HERRING." http://philsci-archive.pitt.edu/313/1/engtot.pdf

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