# Talk:Dissipation

## Dissipative systems and boundaries

The conservation of energy requries that in a closed system (where there is no energy crossing the boundary, either in or out) the total amount remains exactly constant, so adding up all the energies, potential, kinetic, heat gives a constant, measured in joules. Most systems are not closed, and it's a matter of choice where we draw a system boundary. I think it's important to be clear about the thermodynamic manifestation of energy - the generation of heat is not, of course, loss, it is just a movement of the system towards a more entropic state. The heat and noise created by waves may transfer energy to the atmosphere and coastal matter, but in the overall system there is no energy loss. Looking at the sea as a system means there is energy leaving it, but at the same time the sun and wind add energy to it, so it's a dynamic system with flux in and out. Overall I'd say there is conservation in a closed system, but closed systems can consist of many interacting dissipative systems, all exchanging energy. I'm sure someone could express this ina neater form, it's early in the day for me.

Jas 11:50, 12 January 2007 (UTC)

## Biblical Usage of Dissipation

Ephesians 5:18 provides; And do not get drunk with wine, for that is dissipation, but be filled with the Spirit, [5:19] speaking to one another in psalms and hymns and spiritual songs, singing and making melody with your heart to the lord;...

Dissipation used in this biblical context appears to define the term as a concept of a weakening or divided spirituality. —Preceding unsigned comment added by Jentingh1 (talkcontribs) 12:02, 7 April 2009 (UTC)

Sure, but this is about Physics, not superstition. Jas (talk) 20:24, 7 May 2010 (UTC)

## Artificial Dissipation

In many numerical simulations, forms of artificial dissipation are intentionally added in order to make a system numerically stable. For instance, Runge-Kutta 4 is not always stable when using multigrid methods and various modes can grow exponentially at grid boundaries. However, it's been found that intentionally adding small amounts of dissipation over the domain can overcome this problem without significantly affecting the physics being simulated. I don't know the citation but I am certain this is discussed in a book by Kreis and Oliger. —Preceding unsigned comment added by Grigjd3 (talkcontribs) 13:52, 30 September 2010 (UTC)

I was thinking the same thing. One possible citiation is Thomas, J.W. Numerical Partial Differential Equation: Finite Difference Methods. Springer-Verlag. (1995). I've made a cursory change to the main article.

Ovis23 (talk) 21:03, 13 December 2010 (UTC)

## deleted sub-section 'Energy'

I deleted the new sub-section headed 'Energy' because it had a notion of heat that contradicts present Wikipedia thermodynamic consensus. The deleted quote treated heat as a state variable. The present Wikipedia thermodynamic consensus is that heat is a process variable. The source was of a chatty character in a foreign language and was a unsuitable source for an article of this kind.Chjoaygame (talk) 13:00, 15 March 2014 (UTC)

Please provide a source for your claim that the part you mentioned is contradicting the Wikipedia thermodynamic consensus. See for a proper description https://en.wikipedia.org/wiki/Thermodynamics which is very clear on energy and heat. The "deleted quote" treated heat part of a process function, which is considered 101 of Thermodynamics. Prokaryotes (talk) 14:05, 15 March 2014 (UTC)
Heat.Chjoaygame (talk) 23:03, 15 March 2014 (UTC)

## deleted sub-section 'Physics'

I have deleted the new sub-section headed 'Physics" because it was not about physics. It was about computation. The deleted material may well have a place in an article about computation, but it would not be a good plan to try to extend the reach of the present article to cover dissipation in all its possible meanings. The present article is about dissipation as it is meant in physics, especially in thermodynamics.

True, considering that there are uses of the term 'dissipation' other than in physics, especially in thermodynamics, it would be a good idea to change the heading of the present article to 'Dissipation (thermodynamics)' or to 'Dissipation (physics)'. I am not familiar with the process for changing the heading or title of an article. I know it requires special expertise. If anyone here knows the proper process, I would be glad if they would set it in motion.Chjoaygame (talk) 13:11, 15 March 2014 (UTC)

## deleted sub-section 'Mathematics'

I have deleted the new sub-section headed 'Mathematics'. While an advanced article on physical dissipation could perhaps use such material, it is not suitable for the present article, which is not advanced.Chjoaygame (talk) 13:15, 15 March 2014 (UTC)

Hmm, that is because you changed the scope of the article (renaming and such). And this part wasn't new ( i just added a headline), it has been there in your earlier edits. Prokaryotes (talk) 13:52, 15 March 2014 (UTC)
Yes, it should not have been there at all, and should have been removed in the past. Just because I make an edit to one part of an article, I am not obliged to fix every fault in that article.Chjoaygame (talk) 23:05, 15 March 2014 (UTC)

## when all else fails

When all else fails, connect the device with good leads, and turn the power switch to the 'on' position. On no account read the instructions. Well, I did read the instructions, and have moved the page to have a more precise title. It didn't need such great expertise after all!Chjoaygame (talk) 13:31, 15 March 2014 (UTC)

Ok. Well, if you change the scope of an article you shouldn't just start by deleting everything which falls out of your scope. If you change the scope move the other parts to a new article. Prokaryotes (talk) 13:55, 15 March 2014 (UTC)
The inappropriate material that I removed should not have been shoe-horned into the article in the first place. Those who want to post that material should have posted it to a suitable article initially.Chjoaygame (talk) 23:07, 15 March 2014 (UTC)
Chjoaygame (talk), as long this article amounts only to a few paragraph i conclude: No reason to diversify the term at this stage. However, if you insist on term diversity create the relevant articles and move content there, instead of just deleting content. Prokaryotes (talk) 15:03, 16 March 2014 (UTC)

## Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: Moved. I recommend that editors try to reach a consensus on the proper scope of the article before attempting any further moves. Unilateral changes are not helpful when there is still no agreement on what constitutes the subject of the article. One way you might search for consensus is to open an WP:RFC. You might also consider asking for input at some WikiProjects. EdJohnston (talk) 17:39, 24 March 2014 (UTC)

Dissipation (thermodynamics)Dissipation – Page has been moved recently without discussion but the new name doesn't cover the scope of the topic. Prokaryotes (talk) 14:01, 16 March 2014 (UTC) Prokaryotes (talk) 14:01, 16 March 2014 (UTC)

• Support - I would think this is the primary topic for dissipation... Red Slash 19:08, 16 March 2014 (UTC)
With respect, may I ask Red Slash please which precisely is he supporting? Heading the article 'Dissipation (thermodynamics)' or heading it 'Dissipation'?Chjoaygame (talk) 07:05, 17 March 2014 (UTC)
Definitely to put the thermodynamics concept at the main page, dissipation. There may be other uses but this is the primary one. Red Slash 00:21, 18 March 2014 (UTC)
I agree with your view that the main interest of the article is the thermodynamic use of the term. But there is a problem which I would like to ask your thoughts about. When the title of the article lacks the qualifier (thermodynamics), there is an unfortunate tendency that has manifested itself several times, for people to put in scattered bits about other uses of the term, non-thermodynamic uses that would better have their own separate articles. To forestall that unfortunate tendency, I am proposing to add the qualifier (thermodynamics). Would you consider that proposal?Chjoaygame (talk) 03:59, 18 March 2014 (UTC)
I appreciate your concern. One helpful way to stem off additions of extraneous information is to use a hatnote to clarify the specific topic in question. But it is not the job of the article title to clarify that. For instance, Paris is not just the name of the city in France, but also several other very small cities across the world. Yet we title the article Paris and trust that editors will not add random factoids about festivals held in Paris, Texas or whatever. WP:D has a lot of useful information about this. Red Slash 04:52, 18 March 2014 (UTC)
Thank you for this. We will see what happens. At least we can expect to keep the article on one topic, dissipation in thermodynamics, by one means or another.Chjoaygame (talk) 07:31, 18 March 2014 (UTC)
• Oppose - I think the present article should be about, and titled, 'Dissipation (thermodynamics)', not covering other topics, such as dissipation in numerical calculations. I oppose the move as worded above.
As I read the foregoing comment of Red Slash , I think he intends that dissipation in thermodynamics is the primary topic for the article? Please correct me if I am mistaken.
I think the insertion of the three sentences about dissipation in numerical calculations was a mistake that should long ago have been and still now should be rectified by deletion, and if there is someone who wants to create a new article about dissipation in numerical calculations, let him do so. I am not competent to write such a new article. I think that the insertion of three sentences about a topic with clang word association is not a reason to regard that insertion part of the original topic of the article.
Dissipation is a fairly important topic in non-equilibrium thermodynamics, and is a good topic for an article in its own right. Computational dissipation is not a primary part of this subject.
As for the comment about the relation of dissipation to wandering sets, I think that might be suitable for an advanced article on thermodynamic dissipation, but is not suitable for the article in its present stage of being not an advanced article. Therefore I favour just deleting it. If someone wants to create an article about it, of course he is free to do so.Chjoaygame (talk) 07:05, 17 March 2014 (UTC)
• Comment. We usually only disambiguate titles like this when there are multiple articles with the same title, but the main article dissipation now redirects here. This is a only a very minor issue as I see it. Ultimately, the redirect dissipation should probably be changed into a disambiguation page at some later point when and if there is a need for disambiguation, but at present it seems a little early to say one way or another. I think a much bigger problem is that this article is rather unclear and lacking in detail. I think that a lot of real writing work is needed, possibly along the lines of what Chjoaygame has been attempting (although I'm not really qualified to comment on the content). If streamlining the topic of the article could lead to an improved, clearer article, then I fully support this. Sławomir Biały (talk) 12:24, 22 March 2014 (UTC)
The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

## edits today

I have written some notes on the physics of dissipation. Also I have deleted the quote from François Roddier because it is in obsolete terminology that would be misleading to readers unless the obsoleteness was pointed out. In current Wikipedia thermodynamics, heat is not produced, it is manifest only in transfer. I have changed some headings. I have not deleted the entries in the section Dissipation (thermodynamics)#Other uses of the term 'dissipation' out of regard for the concerns of one editor, but I think the section should be deleted in due course.Chjoaygame (talk) 11:45, 18 March 2014 (UTC)

## another edit

I have more or less repeated my revision of the explanation in the lead. I originally wrote the unrevised explanation some time ago, and looking at it now I see it was not a very lucid explanation. I hope my revision is better. Pace an editor who is concerned about the introduction of the heat engine idea here, I think it is helpful.Chjoaygame (talk) 01:38, 19 March 2014 (UTC)

1.) Pick proper section headlines 2.) Do not spam section headlines 3.) Do not proceed with your rewriting of the article scope unless the related discussion has settled. I find your repeated edits without acknowledging input from others not helpful. Prokaryotes (talk) 17:25, 20 March 2014 (UTC)