User talk:ThorinMuglindir

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You may also be interested in the discussions at Wikipedia talk:WikiProject Physics. linas 00:23, 25 October 2005 (UTC)

Heat equation

Thank you for your edits at the Heat equation. I have a remark though. I think your contributions need to be better integrated in the article, and the sectioning needs to be changed. I mean, after all, the heat equation and the diffusion equation are the same thing, but now things look as is they are two, albeit related equations.

In other words, the part about the Green's function needs to go up, etc. Good luck working on it. :) Oleg Alexandrov (talk) 02:41, 25 October 2005 (UTC)

Style remark

One remark. One should not put links into section headings. That is, instead of ==Diffusion== one better write ==Diffusion== and embed the link in the text below. This is good style, rather universally followed on Wikipedia. Thanks. Oleg Alexandrov (talk) 13:03, 25 October 2005 (UTC)

Heat equation, again

I just wonder if you plan to do more work on heat equation. For now it looks that there is one object called "heat equation", and it has an evil twin called "diffusion equation". I think one should use the same "heat equation" terminology throughout most the article, as it is the same equation. More work on integrating your contributions would be needed, so that the stuff in there reads as one article. Wonder what you think. Thanks. Oleg Alexandrov (talk) 02:23, 30 October 2005 (UTC)

I don't mind the way you reversed the move. I do plan more work on it yes, I was thinking introducing the source terms, and explaining briefly that with source terms Green functions are replaced by path integrals (I just have to document myself on this to bring back a few memories). As for integrating the diffusion part better into the article... We could just say that the two equations are the same if you do the k -> D transformation.ThorinMuglindir 02:39, 30 October 2005 (UTC)

I did not completely reversed the order of sections. Originally you put that text at the bottom, then you moved it to the top, and I then put it in the middle. About integrating, more is needed than just saying that k-->D. This article should only talk about the heat equation most of the time, even if you are more familiar with diffusion terminology. Changing terminology in the middle of an article is not a good idea. Heat+diffusion=confusion. :) I will work on it too, but not in the next several days, as I will travel. Oleg Alexandrov (talk) 03:19, 30 October 2005 (UTC)

Heat+diffusion = necessity. I did not move the part about the diffusion equation up because I was unfamiliar with the heat equation, but because you asked for it. You probably should realize that working as an engineer in heat transfers, I am hardly more familiar with the diffusion equation than with the heat equation. So that my supposed ignorance of the heat equation is not the reason why I introduced Green functions starting from the diffusion equation either. The reason is that they are much more easily understood in that context. Though apparently I still need to put some more work on that article, as this might not have been apparent to those who are unfamiliar with physics.ThorinMuglindir 13:52, 30 October 2005 (UTC)

There really need to be two articles: Here it may be reasonable to have two approaches. This may raise eyebrows among NPOV purists, but I think it is entirely justified. Both articles could point to each other.--CSTAR 21:30, 30 October 2005 (UTC)

I am open to two articles pointing to each other, in some conditions. However it is probably better to not start anything serious until we know that at least Oleg is not completely opposed to the idea, and if that can fit with the edits he intended. Global NPOV of the encyclopedia seems to demand that the two article titles be put on the same semantic level. For example diffusion equation vs heat equaton, or mathematical approach to the heat equation vs physical approach to the diffusion equation. ThorinMuglindir 22:01, 30 October 2005 (UTC)

All up to you guys. I think I know about the heat equation less than any of you, my comments were purely editorial (it did not make much sence to treat an equation as "heat equation" only to call it "diffusion equation" in the second half of the article. So I would agree with whatever you two agree with. (Sorry I did not reply so far, I have been traveling.)Oleg Alexandrov (talk) 21:23, 6 November 2005 (UTC)

OK so it seems we are going toward a separation between the articles. I've been trapped online for a few days, but a, back now and it'shigh on my list of edits ThorinMuglindir 14:11, 15 November 2005 (UTC)

Mathematical notation

Hello. Please note the difference in positioning of the two bounds of summation ("i = 1" and "n") below. Also, the capital sigmas have different sizes. The latter is standard. You used the former in probability density function.

$f(t)={\frac {1}{n}}\Sigma _{i=1}^{n}P_{i}\,\delta (t-x_{i}),$

$f(t)={\frac {1}{n}}\sum _{i=1}^{n}P_{i}\,\delta (t-x_{i}),$

Michael Hardy 20:59, 30 October 2005 (UTC)

that is right. I'll try to check if there are other articles where I wrote such sumsThorinMuglindir 21:01, 30 October 2005 (UTC)

PS: In the normal use of TeX, as opposed to the use of Wikipedia's more limited version of TeX, the positioning of the subscripts depends on whether it's "inline" or "displayed", and when \sum is used rather than \Sigma, then the user does not need to worry about the difference because it's built in to the software. Michael Hardy 21:02, 30 October 2005 (UTC)

Re: microscopic definitons of heat and work

1) You wrote: I come to you as the statistical mechanics specialist of the physics project.

Do you refer to me or yourself as the specialist?

I referred to you as the specialist (I could refer to me too as the specialist, but then I'm not from the physics project, I'm just an editor).ThorinMuglindir 19:13, 31 October 2005 (UTC)

Well, I assure you that I'm no specialist in neither statistical mechanics nor thermodynamics. Although I did study it a couple of years ago at university, my field of research is very far away from entropy and Boltzman. In fact, in my models temperature does not exist :) Karol 20:16, 31 October 2005 (UTC)

2) I don't know about which formula is "most general", but there'd be nothing wrong in adding another definition to entropy. The "Shanon" definition you put on my talk page is discussed at information entropy. I guess the entropy article just has focused more on the aspects related to phenomonological thermodynamics and the second law of thermodynamics. Karol 16:35, 31 October 2005 (UTC)

the formula which lets you have any probability for each micro-state is more general as the formula in which all micro-state have to be equally likely. In the micro-canonical ensemble, both formulas can be used. In the canonical, grand-canonical ensembles, only the general formula works for the system itself, though the other formula can still be used to describe the entropy of the system + the outside (it is by maximizing this latter entropy that you demonstrate the maxwell-boltzman weights in the canonical ensemble)ThorinMuglindir 19:13, 31 October 2005 (UTC)

Yes, I know that $-\sum _{n}p_{n}ln(p_{n})=..=ln(N)$ if $\forall n:p_{n}=1/N$. I was referring to a more general generality, nevermind though. Looking forward to your valuable edits. Karol 20:16, 31 October 2005 (UTC)

P.S. What did you mean here by "those 2 text boxes"? Karol 16:45, 31 October 2005 (UTC)

I meant that if you start editing a page, then someone saves an edited version of the page before you save your edit, then you are sent to a page which contains two text boxes, one with your edit, the other with the edit that the other guy has done in the meantime, and then you need to do the merging... If you just hit save, then the edit of the other guy is saved, not yours. If you cut the info in your edit's text box and paste it in the other guy's edit text box, then it's your edit which is saved. The latter is of course not very nice

I don't do that, that's foof. Anyways, my large edits to diffusion where a couple of days before yours. Karol 20:16, 31 October 2005 (UTC)

Heat, heat, heat

I replied two or three sections above this. Oleg Alexandrov (talk) 21:24, 6 November 2005 (UTC)