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Author Topic: quentron.com  (Read 1261356 times)

MarkE

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Re: quentron.com
« Reply #2085 on: February 13, 2014, 03:16:53 PM »
Profitis, thanks. 

So the answer to 1) is that energy is needed to recharge.  Given that reversibility requires that a system can move between two states in either direction without expenditure of energy, it would seem then that the requirement for outside energy to move in the recharge direction means that the process is not thermodynamically reversible.   I think that reinforces rather than refutes the idea that the Nernst equation describes irreversible processes.

I ask that you provide further clarification to your answer to 2).  By "switching between 2 directions of entropy ...", do you mean to say that which way the battery goes depends on the external circumstances?


profitis

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Re: quentron.com
« Reply #2086 on: February 13, 2014, 04:22:09 PM »
@mark E 1) wrong.you,re saying that the word reversability implies spontaneity which it doesnt.a nicad battery is totaly reversable but not spontaneously.it needs work input by you and me to recharge it.work by you and me isnt needed to recharge any karpen system,only a spontaneous reversability is needed,ie.a spontaneous heat-sink. Any voltage including nernst voltage says nothing about reversability,only about spontaneity of reaction.it is only kelvin statement that implies thermodynamic irreversability on everything,thats why its written in textbooks.if nernst equation told us everything about irreversability then kelvin statement wouldnt be needed. 2) only if the rate of discharge exceeds the rate of recharge is a switch needed and that can be powered by the battery itself,eg.transistor so no external influence is required for switching between on/off modes.the original karpen cell used a motor-switch to recharge inbetween discharge pulses.

MarkE

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Re: quentron.com
« Reply #2087 on: February 13, 2014, 05:07:30 PM »
@mark E 1) wrong.you,re saying that the word reversability implies spontaneity which it doesnt.a nicad battery is totaly reversable but not spontaneously.it needs work input by you and me to recharge it.work by you and me isnt needed to recharge any karpen system,only a spontaneous reversability is needed,ie.a spontaneous heat-sink. Any voltage including nernst voltage says nothing about reversability,only about spontaneity of reaction.it is only kelvin statement that implies thermodynamic irreversability on everything,thats why its written in textbooks.if nernst equation told us everything about irreversability then kelvin statement wouldnt be needed. 2) only if the rate of discharge exceeds the rate of recharge is a switch needed and that can be powered by the battery itself,eg.transistor so no external influence is required for switching between on/off modes.the original karpen cell used a motor-switch to recharge inbetween discharge pulses.
Profitis, I said that reversibility requires that a system can traverse either direction between two states without external energy input.  Since the answer to question 1) is that external energy is required to go in the recharge direction, that system is thermodynamically irreversible.  No battery that I know of is thermodynamically reversible.  As you acknowledge with the NiCd external energy is required to recharge. 

There are numerous academic references that state that the Nernst equation at least implies irreversibility based on the Gibbs free energy. 

The Karpen battery's claimed properties are disputed.

I would as much as anyone else love to see a break through discovery in energy.  A macro scale violation of any of the laws of energy would certainly qualify.  That's going to take some rock solid evidence to prove. 

profitis

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Re: quentron.com
« Reply #2088 on: February 13, 2014, 05:16:04 PM »
@mark E i can summerise the whole process like this: work isnt needed by the system to  spontaneously compress gas.a spontaneous heat-sink is needed.

profitis

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Re: quentron.com
« Reply #2089 on: February 13, 2014, 05:17:31 PM »
@mark E.im going to answer your post just now..

MarkE

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Re: quentron.com
« Reply #2090 on: February 13, 2014, 05:31:31 PM »
@mark E i can summerise the whole process like this: work isnt needed by the system to  spontaneously compress gas.a spontaneous heat-sink is needed.
I never considered that there is such a thing as thermal reservoir in some state popping into existence.  That sounds kind of scary.  What would prevent a large reservoir popping up that is at a considerable different temperature than my body at some inconvenient moment?  I don't like the idea that I might instantly evaporate or freeze solid on the whim of some capricious heat sink.

If we stick to one subject to the point of resolution or impasse: Do we agree or disagree on what constitutes thermodynamic reversibility?  I can offer plenty of citations that thermodynamic reversibility requires that a system be able to traverse either way between two states without external energy input.   If you are familiar with a different definition and are relying upon that, then let's get the definition resolved.


profitis

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Re: quentron.com
« Reply #2091 on: February 13, 2014, 06:06:08 PM »
@mark E you asked me if there was consumption of external energy during recharge phase when a compressed gas is released.what happens when we compress a gas in a cylinder then release it? Heat energy flows in from the environment not so? You didnt ask me if work was required by us to recharge the cell which is what im trying to explain here. We can compress a gas in a cylinder and release it a million cycles over,but not spontaneously.its a pretty reversable process but not spontaneously.if your talking about THERMODYNAMIC reversability then sure i can answer with a yes.the whole karpen cycle is perfectly reversable.100% of heat absorbed is converted to work.the nernst equation says nothing about kelvin statement @mark E but i think the confusion here is about its use to describe deviations from standard reversability of electrode potentials with concentration changes,the foundation of concentration cells.

profitis

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Re: quentron.com
« Reply #2092 on: February 13, 2014, 06:30:57 PM »
@mark E a perfect thermodynamic reversability and heat sink will always pop up into existence in any system that has at least 2 assymetric entropy states like a quenco for example: on mode= equalization of electrochemical potential.off mode= redistribution of electron gas charge.

MarkE

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Re: quentron.com
« Reply #2093 on: February 13, 2014, 06:40:19 PM »
@mark E a perfect thermodynamic reversability and heat sink will always pop up into existence in any system that has at least 2 assymetric entropy states like a quenco for example: on mode= equalization of electrochemical potential.off mode= redistribution of electron gas charge.
Profitis, I am sorry but I cannot parse that sentence into anything meaningful and true.

Reversibility or non-reversibility is a an intrinsic quality of a system.  Reversibility is not a property that can be dynamically changed.

Heat sinks are reservoirs.

I do not know of any things that have "2 assymetric (sic) entropy states", including the claimed Quenco device. Quencos have so far never worked. 

I think we are getting further and further from reality here.

profitis

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Re: quentron.com
« Reply #2094 on: February 13, 2014, 07:28:12 PM »
ok @mark E lets rather deal with something that is claimed to exist by established sources e.g. wikipedia.perhaps if i ask you a few questions then there,l be less confusion for everyone.can you tell me how an oxygen electrode concentration cell will reach equilibrium spontaneously? Im talking about 2 platinum oxygen electrodes in same electrolyte with different exposure to gas in a closed system here.   

MarkE

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Re: quentron.com
« Reply #2095 on: February 13, 2014, 07:37:15 PM »
ok @mark E lets rather deal with something that is claimed to exist by established sources e.g. wikipedia.perhaps if i ask you a few questions then there,l be less confusion for everyone.can you tell me how an oxygen electrode concentration cell will reach equilibrium spontaneously? Im talking about 2 platinum oxygen electrodes in same electrolyte with different exposure to gas in a closed system here.
It is basic chemistry that two reservoirs with different ion concentrations that are allowed to communicate will change concentrations until they reach equilibrium.  Is there even a question about that?

profitis

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Re: quentron.com
« Reply #2096 on: February 13, 2014, 07:43:43 PM »
im talking about an oxygen gas electrode concentration cell @mark E not an ionic one.can you tell me what must spontaneously shift from one electrode to the other to go to equilibrium...

MarkE

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Re: quentron.com
« Reply #2097 on: February 13, 2014, 07:58:27 PM »
im talking about an oxygen gas electrode concentration cell @mark E not an ionic one.can you tell me what must spontaneously shift from one electrode to the other to go to equilibrium...
As far as I know, the mere existence of the concentration disparity of two species and the ability of the two concentrations to physically communicate is sufficient to cause the system to drive towards equilibrium.  I would ask the complementary question:  If the species can communicate what is there to keep them from driving towards equilibrium?

profitis

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Re: quentron.com
« Reply #2098 on: February 13, 2014, 08:09:49 PM »
precisely @mark E.what is keeping the system so dead-stable in communication and yet giving a classical nernst potential in direct proportion to relative gas exposures of electrodes???

MarkE

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Re: quentron.com
« Reply #2099 on: February 13, 2014, 08:19:19 PM »
precisely @mark E.what is keeping the system so dead-stable in communication and yet giving a classical nernst potential in direct proportion to relative gas exposures of electrodes???
Communication is a physical condition of materials being in contact directly or through an intermediary fluid.  It is a stipulation.  Since such configurations are what the Nernst equation describes potentials for, what is unusual here that might make the Nernst equation inapplicable?