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THE FALSE SECOND LAW OF THERMODYNAMICS



 
 
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Old January 1st 14, 06:09 PM posted to sci.astro
Pentcho Valev
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Default THE FALSE SECOND LAW OF THERMODYNAMICS

The original formulations of the second law of thermodynamics have made it unfalsifiable:

http://en.wikipedia.org/wiki/Kelvin%...anck_statement
"The Kelvin-Planck statement (or the heat engine statement) of the second law of thermodynamics states that it is impossible to devise a cyclically operating device, the sole effect of which is to absorb energy in the form of heat from a single thermal reservoir and to deliver an equivalent amount of work. This implies that it is impossible to build a heat engine that has 100% thermal efficiency."

How can one refute this? By building the device and showing it to a jury? But there can be various other, e.g. purely technological, reasons (that have nothing to do with the second law of thermodynamics) why this would be difficult or even impossible.

Here I am going to convert the above unfalsifiable version of the second law of thermodynamics into an easily refutable one.

For a closed system (exchanges energy but not matter with the surroundings) the first law of thermodynamics defines the internal energy change, dU, to be:

dU = dQ - dW = dQ - FdX /1/

where dQ is the heat absorbed, dW is the work done by the system on the surroundings, F0 is the work-producing force and dX is the respective displacement.

Let us consider a system with two work-producing forces, F1 and F2 - here is an illustration:

http://chemmaster.co.in/chapters/img/SL42.jpg

We assume that the system does work UNDER ISOTHERMAL CONDITIONS (that is, the system converts heat absorbed from the surroundings into work but operates so slowly, virtually reversibly, that the temperature of both the system and the surroundings remains unchanged). The work done by this system on the surroundings is:

dW = dW1 + dW2 = F1dX1 + F2dX2 /2/

Is W a function of X1 and X2? If yes, the second law of thermodynamics (Kelvin-Planck version) is obeyed - at the end of the (isothermal) cycle W returns to its initial value and no net work is done on the surroundings.

The following theorem is relevant:

Theorem: W is a function of X1 and X2 if and only if the mixed partial derivatives are equal:

http://www.youtube.com/watch?v=Y-lEuHpTS9k
"Mixed Partial Derivatives"

Since F1 and F2 are in fact the first partial derivatives, the theorem can be expressed in the following way:

Theorem: W is a function of X1 and X2, that is, the second law is obeyed, if and only if:

dF1/dX2 = dF2/dX1 /3/

where "d" should be the partial derivative symbol - when X2 varies, X1 is fixed and vice versa.

In terms of the system with two work-producing forces which does work under isothermal conditions, the second law now states:

SECOND LAW OF THERMODYNAMICS (KELVIN-PLANCK VERSION): The partial derivatives dF1/dX2 and dF2/dX1 are EQUAL.

That is, if experiments show that the two sides of /3/ are equal, the second law is confirmed. If, however, experiments unambiguously show that the two sides of /3/ are not equal - e.g. dF1/dX2 is positive and dF2/dX1 negative - the second law of thermodynamics is false and will have to be abandoned..

Consider, for instance, the so-called "chemical springs". There are two types of macroscopic contractile polymers which on acidification (decreasing the pH of the system) contract and can lift a weight:

http://pubs.acs.org/doi/abs/10.1021/jp972167t
J. Phys. Chem. B, 1997, 101 (51), pp 11007 - 11028, Dan W. Urry, "Physical Chemistry of Biological Free Energy Transduction As Demonstrated by Elastic Protein-Based Polymers"

Polymers designed by Urry (U) absorb protons as their length, Lu, increases, whereas polymers designed by Katchalsky (K) release protons as their length, Lk, increases. (See discussion on p. 11020 in Urry's paper: "stretching causes an uptake of protons", for Urry's polymers, and "stretching causes the release of protons", for Katchalsky's polymers).

Let us assume that two macroscopic polymers, one of each type (U and K) are suspended in the same system. At constant temperature, IF THE SECOND LAW IS TRUE, we must have

dFu / dLk = dFk / dLu

where Fu0 and Fk0 are work-producing forces of contraction. The values of the partial derivatives dFu/dLk and dFk/dLu can be assessed from experimental results reported on p. 11020 in Urry's paper. As K is being stretched (Lk increases), it releases protons, the pH decreases and, accordingly, Fu must increase. Therefore, dFu/dLk is positive. In contrast, as U is being stretched (Lu increases), it absorbs protons, the pH increases and Fk must decrease. Therefore, dFk/dLu is negative. One partial derivative is positive, the other negative: this shows that the second law of thermodynamics is false.

Pentcho Valev
  #2  
Old January 2nd 14, 01:10 PM posted to sci.astro
Pentcho Valev
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Posts: 8,078
Default THE FALSE SECOND LAW OF THERMODYNAMICS

In 1824 Sadi Carnot deduced the prototype of the second law of thermodynamics from a postulate that eventually turned out to be false:

Carnot's false postulate: Heat is an indestructible substance (caloric) that cannot be converted into work by the heat engine.

Consequence (prototype of the second law of thermodynamics) : As the heat engine produces work, A COLD BODY IS NECESSARY.

That is, since the heat is not converted into work in the heat engine (in accordance with Carnot's false postulate), a cold body is necessary to accept ALL THE HEAT taken from the warm body.

Unpublished notes written in the period 1824-1832 reveal that, after discovering that his postulate was false, Carnot started to doubt the necessity for a cold body:

http://www.nd.edu/~powers/ame.20231/carnot1897.pdf
REFLECTIONS ON THE MOTIVE POWER OF HEAT, Sadi Carnot: p. 225: "Heat is simply motive power, or rather motion which has changed form. It is a movement among the particles of bodies. Wherever there is destruction of motive power there is, at the same time, production of heat in quantity exactly proportional to the quantity of motive power destroyed. Reciprocally, wherever there is destruction of heat, there is production of motive power." p. 222: "Could a motion (that of radiating heat) produce matter (caloric)? No, undoubtedly; it can only produce a motion. Heat is then the result of a motion. Then it is plain that it could be produced by the consumption of motive power, and that it could produce this power. All the other phenomena - composition and decomposition of bodies, passage to the gaseous state, specific heat, equilibrium of heat, its more or less easy transmission, its constancy in experiments with the calorimeter - could be explained by this hypothesis. But it would be DIFFICULT TO EXPLAIN WHY, IN THE DEVELOPMENT OF MOTIVE POWER BY HEAT, A COLD BODY IS NECESSARY; why, in consuming the heat of a warm body, motion cannot be produced."

Now, almost 200 years later, Carnot's question is still relevant:

Carnot's question (asked after discovering that his postulate was false): WHY, IN THE DEVELOPMENT OF MOTIVE POWER BY HEAT, A COLD BODY IS NECESSARY?

Answer: Generally a cold body is not necessary, that is, the second law of thermodynamics is false. The cold body is only TECHNOLOGICALLY necessary as it makes heat engines fast-working. Heat engines working under isothermal conditions (in the absence of a cold body) are possible but are too slow-working to be of interest to the industry. On the other hand, thermodynamicists don't discuss them because they violate the second law of thermodynamics.. So effects suggesting that isothermal work production is possible are rarely described in the literature, and usually any mentioning of the second law of thermodynamics is avoided:

http://physicsworld.com/cws/article/news/48889
"Researchers at Hong Kong Polytechnic University claim to have invented a new kind of graphene-based "battery" that runs solely on ambient heat. The device is said to capture the thermal energy of ions in a solution and convert it into electricity."

http://scitation.aip.org/content/aip...1063/1.4825269
Electricity generated from ambient heat across a silicon surface, Appl. Phys. Lett. 103, 163902 (2013): "We report generation of electricity from the limitless thermal motion of ions across a two-dimensional (2D) silicon (Si) surface at room temperature. (...) This finding provides a self-charging technology for energy harvesting from ambient heat."

http://arxiv.org/abs/1203.0161
Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment, Zihan Xu et al: "Moreover, the thermal velocity of ions can be maintained by the external environment, which means it is unlimited. However, little study has been reported on converting the ionic thermal energy into electricity. Here we present a graphene device with asymmetric electrodes configuration to capture such ionic thermal energy and convert it into electricity. (...) To exclude the possibility of chemical reaction, we performed control experiments... (...) In conclusion, we could not find any evidences that support the opinion that the induced voltage came from chemical reaction. The mechanism for electricity generation by graphene in solution is a pure physical process..."

http://physics.aps.org/synopsis-for/...ett.108.097403
"Physicists have known for decades that, in principle, a semiconductor device can emit more light power than it consumes electrically. Experiments published in Physical Review Letters finally demonstrate this in practice, though at a small scale. (...) Decreasing the input power to 30 picowatts, the team detected nearly 70 picowatts of emitted light. The extra energy comes from lattice vibrations, so the device should be cooled slightly, as occurs in thermoelectric coolers. These initial results provide too little light for most applications. However, heating the light emitters increases their output power and efficiency, meaning they are like thermodynamic heat engines..."

http://physicsworld.com/cws/article/news/48882
"At first glance this conversion of waste heat to useful photons could appear to violate fundamental laws of thermodynamics, but lead researcher Parthiban Santhanam of the Massachusetts Institute of Technology explains that the process is perfectly consistent with the second law of thermodynamics. "The most counterintuitive aspect of this result is that we don't typically think of light as being a form of heat. Usually we ignore the entropy and think of light as work," he explains. "If the photons didn't have entropy (i.e. if they were a form of work, rather than heat), this would break the second law. Instead, the entropy shows up in the outgoing photons, so the second law is satisfied."

http://www.dailytech.com/An+Incredib...ticle21285.htm
"Overcoming technical challenges, the University of Illinois team used an atomic force microscope tip as a temperature probe to make the first nanometer-scale temperature measurements of a working graphene transistor. What they found was that the resistive heating ("waste heat") effect in graphene was weaker than its thermo-electric cooling effect at times. (...) Further, as the heat is converted back into electricity by the device, graphene transistors may have a two-fold power efficiency gain, both in ditching energetically expensive fans and by recycling heat losses into usable electricity.. Professor King describes, "In silicon and most materials, the electronic heating is much larger than the self-cooling. However, we found that in these graphene transistors, there are regions where the thermoelectric cooling can be larger than the resistive heating, which allows these devices to cool themselves."

http://arxiv.org/ftp/arxiv/papers/1207/1207.6599.pdf
"We have studied the Si devices to generate electricity from thermal motion of ions in aqueous electrolyte solutions at room temperature. (...) However,, this finding does not agree with the second law of thermodynamics, which limits the utilization of the random thermal motion of ions to be spontaneously collected to produce electricity. We cannot explain why either this experiment or the previous experiment of graphene did not agree with the traditional theory. More research will be required to fully understand this phenomenon."

Pentcho Valev
 




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