User talk:Jdpipe
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[edit] Real and Imaginary...
You made some edits on the thermodynamics page about real and imaginary boundaries. I don't think you actually explained what is meant by those terms. To me, it read a little like "it can be A or B. A is A and B is B". Perhaps you could expand? --Jdpipe 00:59, 3 April 2007 (UTC)
- Hi, Jd. Yes those terms could use some more clarifying; however, that particular contribution was made by an anonymous user prior to my edit, I was just cleaning it. I’ll see if I can think of some good clarifying examples over the coming days. Basically, however, the “boundary” is simply an imagery dotted line drawn around the volume of a something in which there is going to be a change in the internal energy of that something. Anything that passes across the boundary that effects a change in the internal energy of that something needs to be accounted for in the energy balance equation. That “something” can be the volumetric region surrounding a single atom resonating energy, such as Max Planck defined in 1900, it can be a body of steam or air in a steam engine, such as Sadi Carnot defined in 1824, or it can be the body of a tropical cyclone, such as K. Emanuel theorized in 1986, or it can a single nuclide, i.e. a system of quarks, as some are currently theorizing presently. Later: --Sadi Carnot 01:24, 3 April 2007 (UTC)
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- So that use of terms is revolving around the idea that a real boundary is something hard, as opposed to an arbitrary surface drawn in space. I suppose that in open systems we expect mass transfer across boundaries but in close systems we do not. Perhaps that is the distinction that is required. Jdpipe 02:16, 3 April 2007 (UTC)
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- Basically, yes; if mass transfers across the system, however, the system is considered open and chemical potential terms are added to the energy balance equation to quantify how the internal energy of the system changes as each particle passes the imaginary (a fictitious delineation in space) or real boundary (such as a cell membrane). The definitions really are only superficial; it is the manner in which the differential equations are applied to quantify all the details of the problem that really matters. --Sadi Carnot 14:28, 3 April 2007 (UTC)
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