User talk:PAR/archive 2

• User talk:PAR/archive 1

Statistical mechanics, thermodyanmics and all the related goodies

Hey there! I thought you deserve a barnstar for your extensive contributions to articles on Wikipedia, particularly those related to statistical mechanics, thermodynamics and probability theory. May it be a constant reminder that your work and efforts are appreciated here! --HappyCamper 03:22, 24 November 2005 (UTC)

Hey there! - Thanks, I appreciate that. PAR 03:44, 24 November 2005 (UTC)

Just thought that I's say that I like the work on the law of thermodynamics too ... you might want to bold the Third law of thermodynamics statement also though (for continuity between the articles). Sincerely, JDR 22:16, 29 November 2005 (UTC)

Hot & Cold Photons?

I've left some comment on the thermodynamic evolution "Talk Page". Let me know if you have suggestions. Thanks:--Wavesmikey 04:49, 26 November 2005 (UTC)

GBthumb

I have replied on my talk page. -- RHaworth 18:59, 27 November 2005 (UTC)

Pressure

Best edit summary ever! ;-) --Calair 06:00, 30 November 2005 (UTC)

Principles of energetics

Can you help out with the article Principles of energetics, which has lots of thermodynamic content, but from the point of view of ecology? linas 16:41, 4 December 2005 (UTC)

Polylogarithm

Can you take a look at my question at Wikipedia:Reference_desk/Mathematics, about a function that is related to the polylog, but is a generalization of some sort I can't identify. Perhaps it may ring a bell? linas 16:41, 4 December 2005 (UTC)

Thermodynamics

I have begun to work on the thermodynamics page as it needs serious edits. Please do not revert my changes without discussing it with me first. I requested this in the discussion page for the article as well. Lagrangian

Cooperation

Rather than berate me on a WT:AUM, why don't you tell me exactly what is wrong. I'll be happy to help where I can. -- Netoholic @ 16:24, 19 December 2005 (UTC)

It wasn't personal, I was just describing the effects of your edits on articles that I have written, and not acting very happy about it. There are two main problems:

• Template:Thermodynamic equations - I changed the "If" to "qif" and it seems to work, but I don't know if the qif template is going to keep working or not.
• Template:Infobox_City which was using the Template:GBNewYorkState template to display a map. The cities using the GBNewYorkState template for displaying maps now have no maps. (three total I think - not as bad as I thought)

Thanks for the offer of help, and any help would be appreciated - PAR 19:37, 19 December 2005 (UTC)

Well, I fixed up Template:Thermodynamic equations preemptively after looking at your post. I replaced qif and it seems to be working well. As for Template:GBNewYorkState, it's an interesting idea, but doesn't seem like it'll be a practical method for most users nor does it conform to WP:AUM as is. -- Netoholic @ 22:27, 19 December 2005 (UTC)

Can you tell me, is Template:GBNewYorkState all right as it is, but should not be included in a Template:Infobox_City (where it was involved with a conditional template) or is there something wrong with it as it stands? Thanks - PAR 01:49, 20 December 2005 (UTC)

Also - are there instructions somewhere on the use of the "class=hiddenStructure" construct? PAR 21:36, 24 December 2005 (UTC)

Paul Dirac

Hi PAR, I was wondering if you'd be in a position to help fix some apparent errors in the article on Dirac. See the list of errors identified recently by Nature: Wikipedia:External peer review/Nature December 2005/Errors#Paul Dirac. Thanks! --MarkSweep (call me collect) 21:45, 22 December 2005 (UTC)

Hi MarkSweep - I'm not so good with the history of physics so I will concentrate on the technical parts first. PAR 23:43, 22 December 2005 (UTC)

Don't feel obligated. Thanks for your help! --MarkSweep (call me collect) 00:02, 23 December 2005 (UTC)

Classical field theory

Your additions to the SR page are welcome, but I think some of them are really applications of SR in describing the universe. I think this would fit better in the Classical field theory page. What do you think? Masud 15:22, 24 December 2005 (UTC)

I think changing the name of the current Classical field theory to lagrangian formulation of electrodynamics would be useful. in that case much of your writing from this article can go in there. Masud 20:33, 24 December 2005 (UTC)

You may be right about the electrodynamics stuff going somewhere else. I looked at Maxwell's Equations and the same stuff is in there too. I have no objection to any of it being moved to an appropriate place. I question whether classical field theory should be narrowed down to electrodynamics. Where will classical field theory in general be dealt with? PAR 21:12, 24 December 2005 (UTC)

That's what I originally thought, but other Wikipedians don't agree. Take a look at Talk:Classical field theory#Name change? I'm inclined to agree with Linas. Masud 09:31, 25 December 2005 (UTC)

Ship table

I've come across Template:Ship table before and have been working on a replacement at Template:Infobox Ship. This replacement does not use meta-templates and also simplifies the parameter names. I've converted a couple of articles to use it, so maybe you could take a look and make some final suggestions. If it looks fine, I can run a bot process which will convert all the ship articles. -- Netoholic @ 18:48, 29 December 2005 (UTC)

Hi - yes, that's what I was trying to do. But it needs:

• A way to include a NavyColor parameter to set the bar color to a user-chosen color, with "navy" as the default
• A way to display "unknown" as the answer to a required variable if that required variable is missing.

Is this doable? PAR 12:37, 30 December 2005 (UTC)

I removed the Edit link because it is misleading to novice editors. They will see it and believe they are editing the content of the page's infobox, but instead are taken to the template source. For advanced users, they are all aware that a link to the template exists at the bottom of the article's Edit screen. It's basically of no benefit either way. -- Netoholic @ 01:15, 31 December 2005 (UTC)

Thanks for your email. I've had a run-in with Netoholic over this one, and I was not pleased that the user went ahead and wrote things without even having the grace to contact me. Let me give you a bit of background on why the navy blue colour for the ship table is there. The Wikiproject: Ships is one of the oldest and largest on Wikipedia. The standard table design was developed for that wikiproject back in the days before wiki table markup existed, meaning that we had to use HTML table markup back then (for examples look at some of the USN carrier or battleship articles). The standard colour was decided as a dark blue and it has not altered in several years. We have gone through using wiki markup for tables, a hacked together version of my template using very clumsy syntax, changing that to use QIF and then changing it again to using the CSS trick. Through all of those iterations the blue has remained. It's not a Union vs Confederacy thing, it's just inertia and convenience and wikiproject choice. I suggest that you go and join that project and post about the colour scheme for the standard table sinec that's where you'll be able to get input from the people most interested in the subject. Personally I'm not that keen on changing things since I think using a dark/navy blue is very suggestive of the ocean, but my opinion is far from the only one that matters. David Newton 22:21, 20 January 2006 (UTC)

Thanks for your response - when you say "join that project", which project is that? PAR 02:57, 21 January 2006 (UTC)

I mean this: Wikipedia:WikiProject Ships. WikiProjects are groups of users who come together to try and hammer out standard formats for articles about a particular subject. For example, whilst working on ship articles you might have noticed that they do not necessarily conform to the usual disambig rules. That is because the rules for ship article disambig nomenclature were settled by the WikiProject before the main rules on disambig nomenclature were written. The WikiProject also designed the standard ship table.

BTW, just to let you know, I've reverted the standard ship table to the QIF form. I've done that because one of the developers, Brion Vibber, has said that the use of things like QIF in templates is NOT a massive server load. QIF syntax provides functionality that the CSS hack does not and so since the main reason for changing things over the last month is gone I have reverted. That does mean that a couple of your additions are no longer there but I will see about adding them back in later today when I have a bit more time (lunchtime will be over soon).

I hope to see you at the WikiProject Ships soon so that you can share in the collective experience, and we can benefit from your insights. David Newton 13:18, 24 January 2006 (UTC)

Thanks, I didn't know about that. I will check in. I hope my edits of the Confederate ships have not been a problem. PAR 16:08, 24 January 2006 (UTC)

Your edits are not a problem. You did them in good faith and did not know about the WikiProject. I've added in a variable Ship notes to the table to replace part of what you put in with Note1. I presume that you added the variable to enable things that aren't covered elsewhere in the table to be inserted if they are particularly notable. I've put as much in the documentation of the template. Please let me know if I am mistaken about the intent of the variable insertion. I'm more leery of reinserting NavyColor as a variable because its functionality could potentially break existing uses of the table, and also because I don't really see why using navy blue for Confederate vessels is NPOV. I suggest you bring the subject up at the WikiProject talk and see what others think. If there is an consensus, then I will certainly be happy to reinsert it. I also think that fiddling round to see if we can get a better implementation of the alternative US/UK versions of various spellings is a good idea. David Newton 17:32, 24 January 2006 (UTC)

Yes, I ran into a few cases where there was information in a table that was not contained in the template, and it was a one-time situation, so I added the "Note1" field. I called it Note1 just in case a "Note2" field was needed, but thankfully, thats not the case.

With regard to color, I put in a petition at the project page. PAR 21:02, 24 January 2006 (UTC)

notation changes at DFT?

Hi PAR, I thought everyone had agreed to change (N,j,k) to (N,k,n) in Discrete Fourier transform and friends. Why did you change it to (N,m,n) instead? Like it or not, k is much more common for the output index in the DFT. (Analogously, k is often used as the momentum-space variable in physics for spatial Fourier transforms.)

Please change it to what everyone agreed upon, thanks.

—Steven G. Johnson 01:14, 31 December 2005 (UTC)

Ok, no problem. Give me a day or less. PAR 01:17, 31 December 2005 (UTC)

Thanks, PAR. —Steven G. Johnson 01:26, 31 December 2005 (UTC)

removal of diagram

Hello Par - I think it was a mistake to remove the tetrahedral group cycle graph (not that I am biased...). Here's why. Wikipedia math entries should be ideally accesible to anyone, not just the already math-literate or math-educated. We don't need it to become another Mathworld clone. So I made that diagram with the specific intent of having the concept of a group cycle graph, along with other concepts such as symmetry group/rotation group etc, be presented visually. Many people learn best visually, and to be able to see how doing three 120degree rotations brings you back to the original position will help someone understand what a group cycle means, in a way that (a²b)²=e might not. As for not showing all features of a graph cycle (such as labelling e), well, that can be easily addressed. What do you say? Debivort 03:17, 8 January 2006 (UTC)

thanks for the thermo

Just writing to thank you for the thermo content you've contributed to Wikipedia, especially those great templates. Please have a look at the diagram and content I added to the enthalpy page about how it's applied to open systems. Flying Jazz 08:17, 10 January 2006 (UTC)

Image Tagging Image:Mae West Signature.png

This image may be deleted.

Thanks for uploading Image:Mae West Signature.png. I notice the image page currently doesn't specify who created the image, so the copyright status is therefore unclear. If you have not created the image yourself then you need to argue that we have the right to use the image on Wikipedia (see copyright tagging below). If you have not created the image yourself then you should also specify where you found it, i.e., in most cases link to the website where you got it, and the terms of use for content from that page.

If the image also doesn't have a copyright tag then you must also add one. If you created/took the picture then you can use {{GFDL}} to release it under the GFDL. If you believe the image qualifies as fair use, please read fair use, and then use a tag such as {{Non-free fair use in|article name}} or one of the other tags listed at Wikipedia:Image copyright tags#Fair_use. See Wikipedia:Image copyright tags for the full list of copyright tags that you can use.

If you have uploaded other images, please check that you have specified their source and copyright tagged them, too. You can find a list of image pages you have edited by clicking on the "my contributions" link (it is located at the very top of any Wikipedia page when you are logged in), and then selecting "Image" from the dropdown box. Note that any unsourced and untagged images will be deleted one week after they have been uploaded, as described on criteria for speedy deletion. Thank you. Netoholic @ 05:29, 18 January 2006 (UTC)

CIE 1931 color space

I was wondering why you added the huge "STOP STOP STOP" notice to the existing comment pointing out that Grassmann is correctly spelled with two n's. I don't see any recent edits that mis-corrected it. --Macrakis 00:00, 20 January 2006 (UTC)

My edit corrected it. This is about the fourth time I've had to revert it over the past 6 months or so. I had a notice on there before this one, and it was changed anyway, so I went $#@#%! berserk. I'm ok now, I have resumed my medication, thanks for your concern. Please change it if you think its excessive. PAR 01:00, 20 January 2006 (UTC)

Impedance Matching.

THanks for including the piece on mechanical matching to the article. Is funny because I was only just recently thinking about this concept and how useful it might be in analysing the dynamics of (rigid) bodies and thinking about momentum, KE etc. I have a gut feeling that there may be more to extract from similar analogies, but I haven't thought them out yet. Any way, you seem to be on the same 'wavelength' so I'll mention any ideas I have to you (as soon as I have them)--Light current 03:20, 24 January 2006 (UTC)

I try to think of it as anytime there is a "reflection", there is an "impedance mismatch" and then have a very open attitude as to what constitutes reflection. Reflection is more intuitive to me than impedance. PAR 03:28, 24 January 2006 (UTC)

I agree!! I shall have to reflect more on these things! --Light current 03:37, 24 January 2006 (UTC)

Regarding Image:Masuda1.png

Hi PAR. I was looking at Standard test image and I was wondering who has used Image:Masuda1.png as a test image. Perhaps you could add that information somewhere in the article? I've never seen it before, so I'm curious. Thanks! ~MDD4696 00:38, 26 January 2006 (UTC)

Well, I know it was named for the researcher who first used it. His name is Ichiro Matsuda and there's a list of his publications at http://itohws03.ee.noda.sut.ac.jp/~matsuda/mrp/ and an email address. I believe that the image was first used by him, then by other researchers. I don't know which of the publications use it. Why not email him and ask? PAR 04:24, 26 January 2006 (UTC)

Orientational analysis

Hi PAR, I looked over the section you added to dimensional analysis on orientational analysis, and like much of what I see. However, I do have some reservations about some of it. I don't care for the very first sentence "A problem with Huntley's addition is that it only works when the physical problem is expressed as a scalar, vector, or tensor equation." Orientational analysis works because the equations of physics are tensor eqns., and all physically meaningful equations are tensor equations (includes vectors and scalars). The problem with the sentence is that it seems to imply that orientational analysis works when Huntley's does not, i.e. when the underlying equation is not scalar, vector or tensor. That is not the case.

It is important to emphasize that Huntley's addition as used in all of his cases _never_ makes use of a cross-product sort of rule (Lz=LxLy). The product LxLy =LyLx in his system is irreducible. He claims he makes use of the symmetry of the situation to determine how to write the Huntley symbols for each assumed physical quantity and exactly how he does this would have to be carefully described, were his analysis to be retained. The write-up as it stands does not include the "symmetry problem" of his method, as I call it.

I'm having some difficulty understanding the above. It seems clear that orientational analysis works in all cases where Huntley's works, and more. I don't mean to say that Huntley uses LxLy=Lz, he doesn't. I'm trying to avoid dealing with the "symmetry problem" right now because I can't really quantify it, its like an intuition and I agree, its not straightforward.

The absence of a rule like LxLy = Lz gives problems in another way too. Look at the torque eqn. at the end of the preceding section: "z-component of torque is dimensionally equal to τz = MLxLy / T2." The subscript z used on torque would seem to imply that Lz = Lx Ly or maybe Lz^2=Lx Ly or what? Very confusing. Orientational analysis is unambiguous here. 1z=1x1y. No problemo.

Yes, physical equations involving the cross product are a problem for Huntley, but not for orientational analysis.

Under the dot and cross product equations "Since only parallel orientations yield a non-zero dot product..." is not quite correct. The vectors may be non-parallel. It is rather just that they can't be perpendicular.

Yes, that was a mistake.

Your treatment seems to imply that Lz=L 1z. Where the symbol Lz belongs to Huntley's addition and 1z to orientational analysis. This mixing of symbols leads to contradictions. Orientational analysis is not applied after a Huntley's analysis, but rather after Dimensional analysis. In orientational analysis the orientational and dimensional symbols are never mixed. Two separate sets of equations are set up: first the conventional dimensional analysis, then the (independent) orientational equations set up and solved separately. To set them up requires that the results from dimensional analysis be in normal form, which is not mentioned in the article as it stands.

I don't see how the mixing of symbols leads to contradictions. Can you give a simple example?

It is worthwhile to look at huntley's very first example on p 85 of the Dover addition, which I assume you are following--the nicholson hydrometer vibration. It is not explained there how he got the dimension formulas for cross section of the neck, nor of the density of the liquid, nor for that matter, of gravity. I could argue, using his "symmetry" method, any of a number of reasonable sets. In particular he uses for the area of the neck of the hydrometer, which is bobbing up and down in the z plane, as LxLy. Looks reasonable until you carefully read the case of the moving body in a liquid problem on p 80 -81 where he takes the area (moving in the x-direction) as Lx Ly^.5 Lz^.5. So an area moving through a fluid in the z direction would be Lz Ly^.5 Lx^.5. !!! Similarly, in the same example he uses density as M L^-1 Ly^-1 Lz^-1 rather than Lx^-1 Ly^-1 Lz^-1 (as he does in Ex 3) or even L^-3. His "symmetrization" procedure appears to me to be arbitrary and unpredictable. When I, a mere mortal, try to use his symmetrization procedure on a problem he describes, without looking at his presentation, I almost always get something different. Try it yourself, to see what I mean. I have a very strong impression that he knows the answer to each of the examples, and tries several sets of symmetrization choices, then picks the set that gives him the answer he wants. Tough, I know. But I know for fact that others have the same exact reservation.

I looked at it and, as you say, the nicholson hydrometer example looks good, and when he gets to a torpedo, he changes tactics. I have a feel for what he is doing, but its not clearly shown. I did something similar on a problem, where I used Lr as a radial length and Lz as a z-length, with the cross sectional area being of dimension Lr squared. It works, but again the process requires some intuition.

A strong virtue of orientational analysis, I think, is that they are always crystal clear. Density has orientational symbol of the identity element, always. It doesn't change from problem to problem. Areas always have the straightforward orientational symbol that corresponds to the normal direction. Always. Scalars, such as work, always have the identity element for its orientational symbol. Never varies, no matter how the work was done, and in what directions the forces are applied, nor does it change when the symmetry of the body on which the forces act change. Never.

Yes, I agree.

The last sentence "This method may be extended to higher dimensional spaces for a suitably generalized cross product." is a mystery to me and should be omitted unless you have some reference...

I am operating under the idea that the only dot products involving 1a1b is when a=b and the result is dimensionless so that 1x1x=10 and so forth. The only cross products involving 1a1b is when a and b are different, in which case the result is perpendicular to both. In other words the product rules follow naturally from the various vector and tensor products that you have in 3 space. You have analogous operations in 4-space, and an analogous group structure. I believe that in 4-space there will be 7 irreducible elements: 10, 1x, 1y, 1z, 1xy, 1xz, 1xt with rules like 1xy=1zt, etc. I am quite sure this is valid, but there being no reference, it cannot be included. However, it would be a shame to imply that the orientational analysis is somehow restricted to physical 3-space.

In summary, I believe reference to Huntley's addition should be omitted everywhere, and the orientational analysis section extended a little to show how the procedure works along the lines I give (including normalization, and the reason it is required) and how two separate requirements on physical equations yield two sets of equations, both of which must be satisfied for the starting physical equation to be correct.

DonSiano 22:14, 26 January 2006 (UTC)

Hi Don - I've read what you wrote above, then I read Huntley again, and I see that much of what you say is true. I will make some changes. I'm sure they won't be right, but they will address some of what you say. Then we can talk about further changes. My biggest disagreement is getting rid of Huntley's addition completely. I think a mention of what he did is in order, because he came up with the idea (right?). There should be an example which shows the power of the method he introduced, then an explanation of its shortcomings. Then introduce orientational analysis to show how it is a superior method, including an example which Huntley can't handle. However, I'm not certain of anything at this point, since I'm still learning both methods. PAR 14:47, 27 January 2006 (UTC)

Hi PAR - I think the article is moving in the right direction, and I like all the changes you have made on the last rev. I need to learn more about how to use wiki math notation. The article still needs work, and I am still pretty uncomfortable about spending so much of it on Huntley's addition. Certainly it is ok to describe it, but the two worked examples seems too much to me to give a good balance to the article as a whole. At the very least, the second example should go (noting that he has extended his proposal to mass in this way, perhaps).

And we need some remark about moving from a dimensionless product can alternatively be turned into an equation with one physical variable on the left, and how the dimensionless constant enters. We also need a remark that gives notice to the fact that the dimensionless constant C in so many problems is of order unity. Why is that?

On the higher dimensional space generalization, I didn't mean that I doubted it, but I was concerned that it seems to be more of a curiosity at this point. But who knows, maybe it will lead somewhere interesting...

Well, lets keep working on this for a while yet. We're getting there.

I'm anxious to get a look at what you've been doing on fat tails... DonSiano 17:53, 28 January 2006 (UTC)

Hi Don - I would like to keep the Huntley section more or less the same for now. I think the mass part is useful, it shows that the extension possibilities are not limited to just orientation. I think you downgrade Huntley too much. You give the impression that little of what he did was of any use, and thats not true. He discovered the technique and applied it sucessfully to many cases. He missed the boat on angles and cross products, and he got a little too exuberant with some of his examples, and that's where the orientational analysis picks up the story and does the whole thing more correctly.

I think the higher dimensional stuff is more than a curiosity, it is informative. Even the three space stuff can be made more informative. The cross product of A and B is a pseudovector, so its not really physical, since its value depends on the coordinate system. The truly physical entity is the wedge product of A and B which is an antisymmetric 2-tensor. If AxB=C then

${\vec {A}}\times {\vec {B}}=[C_{x},C_{y},C_{z}]$

and the wedge product is

${\vec {A}}\wedge {\vec {B}}={\begin{bmatrix}0&C_{z}&-C_{y}\\-C_{z}&0&-C_{x}\\C_{y}&-C_{x}&0\end{bmatrix}}$

so you can see that there is a one-to-one correspondence. The cross product is just shorthand for the true entity. The good thing about the wedge product is that it does not change sign when the coordinate system is inverted. It is a "true" physical quantity. Another unique thing about the wedge product 2-tensor is that it can be squared, yielding another 2-tensor with the same dimensional characteristics. If we take your suggestion that an angle is a pseudovector, then by the above argument, its really a 2-tensor. Since it can be squared, we can now have exp(θ) which is also a 2-tensor. However, its not an antisymmetric 2-tensor, so there is no pseudovector to be associated with it. It turns out that exp(θ) is the transformation matrix for converting from one coordinate system to another rotated by angle theta about the axis specified by the vector direction of theta!. Anyway, this line of thinking can go on and on, and there is a lot of neat stuff to be figured out here. PAR 19:35, 28 January 2006 (UTC)

Integral transform

What do you want to say with this edit? -- Jitse Niesen (talk) 23:51, 1 February 2006 (UTC)

Just that the equality of the inverse transformation may not be true at every point. For example, if H(x) is zero for negative x, and unity for x greater than or equal to zero, the inverse Fourier transform of the Fourier transform of H(x) is equal to H(x) except that at x=0, its equal to 1/2. The \sim was used to say that, but it needs to be clearer. PAR 00:05, 2 February 2006 (UTC)

I see what you mean. However, if you want to be rigorous, I think that there are a lot more things to be mentioned there. Just to take your example, if you take the Fourier transform of H to be

$({\mathcal {F}}H)(u)=\int _{-\infty }^{\infty }{\frac {e^{-iut}}{\sqrt {2\pi }}}H(t)\,dt,$

which is the definition in the article, then the Fourier transform does not even exist because the integral does not converge. So, I think we should either give the full details (which may not be so hard; for instance, for Fourier I think it's enough to say that everything is square integrable and "=" means equality almost everything), or we do some hand-waving and say that we assume that everything is well-behaved. -- Jitse Niesen (talk) 16:33, 2 February 2006 (UTC)

Yes, that was a bad example. A function that goes up at zero and returns to zero at x=1 would illustrate the point better. I am in favor of being more detailed about the relationship between the function and the inverse transform of the transform of the function, but I don't know enough to write that with any authority except perhaps the Fourier transform. The hand waving option is the best I can do without doing some research. PAR 07:10, 4 February 2006 (UTC)

Lambertian reflectance

I would like to put a merge message on Lambertian reflectance, suggesting that it be merged with Lambert's cosine law, unless you have an objection. PAR 03:12, 20 February 2006 (UTC)

I thought about doing that too, but hesitated because the former page is very strongly influenced by the computer graphics community, while the latter is more physics oriented. There might be some merit to this separation. Think about it and do what you think is best.--Srleffler 03:22, 20 February 2006 (UTC)

I noticed that too. I think it might be good to have a section in the cosine law article that includes computer graphics applications, but then the computer graphics people might think it would be good to have a physics section in a computer graphics article. I will put the merge message up and see what happens. PAR 01:06, 21 February 2006 (UTC)

Dimensional analysis

Please don't remove copyright-violation templates; replacing the text isn't enough, as the violation is still in the page history. You can place the replacement text at the temp page, and someone (me, if I see it first) can delete the article and replace it with the new one. I know that it's a pain, but blame the person who made the oiginal mess. --Mel Etitis (Μελ Ετητης) 10:16, 25 February 2006 (UTC)

Sorry — I did all this before noticing your message on my Talk page. The thing to do is to move back the Huntley's Analysis. I've now done that, and removed Dimensional analysis from Wikipedia:Copyright problems, so I think that everything should be OK. --Mel Etitis (Μελ Ετητης) 10:22, 25 February 2006 (UTC)

Polylogarithm

Hi,

I think I found an error in the polylogarithm article. If I remember the article history correctly, this would be in a section you've added. Can you please review? I'm rather desperate, as this seems to be the source of an error that perpetuated itself into my calculations. 14:13, 2 May 2006 (UTC)

Impedance & thermodynamics

Hello PAR.

Previously you wrote "I don't think gear changing is a form of impedance matching" on the thermodynamics talk.

User:Light current has posed an opposing view at impedance matching talk.

I would be interested to read your response. Regards, Sholto Maud 03:23, 3 May 2006 (UTC)

Hello again PAR.

Thankyou for your contributions to the impedance mathcing discussion. I've moved discussion to the analogical models page where it seems more appropriate. Sorry to disturb you again. Lightcurrent and myself are having trouble with finding the analog definitions for load rotational resistance and internal rotational resistance if you are able to help clarify the matter it would be most useful. Thanks again. Sholto Maud 04:24, 6 May 2006 (UTC)

Commons images

Hi, two of your images commons:Image:Pulley0.png and commons:Image:Pulley3a.png does not have any license. --Tomia 20:57, 17 May 2006 (UTC)

Fixed - thanks PAR 15:30, 20 May 2006 (UTC)

please take a look at:

Talk:Sinc_function_(unnormalized) . i am reasserting the issue of the primary definition of sinc function and am proposing that the primary definition be changed to $\mathrm {sinc} (x)\equiv {\frac {\sin(\pi x)}{\pi x}}\$ with mention to the historical definition (without the π factors) as the alternative definition and the one that fits the zero^th order spherical Bessel function of the first kind without scaling. whereas i respectfully disagree with you, i really do want your position to be represented in the discussion. r b-j 21:31, 31 May 2006 (UTC)

question

Hello

Please see my question on Talk:Internal energy. eman 13:32, 2 June 2006 (UTC)

Knot pictures

Hi,
I've been looking at the file history and copyright status of some pictures of knots. I see that you uploaded image:Grannyknot.png. Do you know anything about the provenance of image:Fishknot.png and image:Sqrknot.png? They're very similar stylistically to your image, but we have no license information for them, and seem to have lost the uploader's identity. I've placed your talk page on my watchlist, so you may reply right here, to keep the discussion all in one place. --Smack (talk) 21:07, 12 June 2006 (UTC)

I generated the granny knot and the grief knot images to be as close as possible stylistically to the two you mentioned, but I did not generate them. Let me know if there are problems, and I will generate four new images from scratch. PAR 00:25, 13 June 2006 (UTC)

I don't think there's anything wrong with your images. The older images, though, are unlicensed and, theoretically, subject to deletion. How did you make your images? They look suspiciously like derivative works, in which case you can't PD them. --Smack (talk) 01:27, 13 June 2006 (UTC)

They are deriviative. I took the older images, and modified them to form the new ones. I will generate some new ones, please delete all four. PAR 03:56, 13 June 2006 (UTC)

I uploaded the following images to the Wikipedia Commons using the PD-self tag

Square Knot

Granny Knot

Thief Knot

Grief Knot

I inserted SquareKnot.png into the square knot article, but it did not seem to display and I don't know why. Anyway, these images are now avialable with good copyright tags. PAR 05:00, 13 June 2006 (UTC)

Looks nice. --Smack (talk) 20:36, 13 June 2006 (UTC)

P.S. Would you mind if I tagged the derivative images as "source unknown" instead of your PD tags? --Smack (talk) 20:38, 13 June 2006 (UTC)

Once we can figure out why some of the new images don't show up, lets just delete all the old ones. I can't figure out why the granny knot picture displays, but the square knot picture does not. I thought it might have to do with the fact that the square knot was in a template, but even outside the template it seems to be flaky. Is it just me or do you have the same trouble? PAR 22:55, 13 June 2006 (UTC)

I think I know what's going on here. See this discussion. --Smack (talk) 01:37, 14 June 2006 (UTC)

Good, I was hoping it was not some subtle problem in the files I uploaded. PAR 03:22, 14 June 2006 (UTC)

I was able to insert the new images in their respective articles by purging each image (and reloading the page containing the image). PAR 12:37, 20 June 2006 (UTC)

Good work. How did you do it, exactly? --Smack (talk) 05:06, 21 June 2006 (UTC)

I went to each image page (In the commons) and edited it, putting in {{purge|purge}}. Then I hit the "Show preview" button, and hit the word "purge" in the preview. Then I went to the article with the knot picture and hit "reload" in my browser. PAR 16:49, 21 June 2006 (UTC)

Ah, that sneaky commons. That's what I was missing. --Smack (talk) 05:11, 25 June 2006 (UTC)

enthalpy and unternak energy

hi

Could you please look at my question on Talk:Enthalpy#contradiction? - is dQ = dH in isobaric chemical reactions?, and Talk:Internal energy#U=TS-PV?/

Thanks
eman 17:56, 28 June 2006 (UTC)

Image:GBRedDot.png not displaying in IE

The creator of the template Template:Infobox Town NY has modified the template so it accepts this image template you created. Which means no creating unique image files for every location in NYS, so thank you very much! What a great combination! However, in testing it I discovered that the red dot image () does not display in MS IE. Initially I thought it was a problem with the template, but it seems the actual image does not like IE (I'm using 6 on an XP SP2 platform); the state image display fine. I get both just fine in the latest version of Firefox. Any ideas? Thanks. Jim Dunning 18:18, 31 July 2006 (UTC)

I adapted this from Template:GBthumb by User:RHaworth. My discussions with him are at User talk:RHaworth/Archive to 2006 January#GBthumb template. He's the guy to talk to about this. I have Firefox, which is why it works on firefox, but I think MS IE is non-standard. PAR 22:18, 31 July 2006 (UTC)

Planck's law

You wrote:

Thomas - don't change it. You forgot to transform the differential dν. In other words, you don't want to say

$I(\nu )=I(\lambda )\qquad \mathbf {(WRONG)}$

you want to say:

$I(\nu )d\nu =I(\lambda )d\lambda \qquad \mathbf {(RIGHT)}$

Since λν = c, you have dλ = − cdν / ν2 and dν = − cdλ / λ2. If you redo the math, and realize that the signs on the differentials don't matter, you will see that everything is ok. PAR 16:23, 31 July 2006 (UTC) Retrieved from "http://en.wiki.x.io/wiki/Talk:Planck%27s_law_of_black_body_radiation"

PAR - you are obviously right! I am really glad I didn't change it in the main article. I rely heavily on Wikipedia when doing research, so I would be ashamed of introducing mistakes myself. Actually, I went home after having written my comment and already on the way home the penny fell and I saw that the units were correct indeed.

I deleted the comment from the discussion page of "Planck's law" in order to avoid that others might doubt the credibility of the article. Many thanks for the correct answer though, because it was only after seeing it from you that I knew that my ultimate thought on that days way home was the right one. Otherwise who knows how long it might have bothered me.

Thanks for all the work done on Wikipedia, it looks like a hell of a lot of time you are putting into it,

Thomas

Hi Thomas - Glad to help. I've been contributing on and off for a couple of years, and it adds up. Also - it's generally bad form to modify a talk page except to add to it, so you shouldn't have erased the discussion. (I see it has been restored, so no problem now). I broke the rules by modifying what you wrote, but I was hopeful that anyone comparing the two would see that I only reformatted what you wrote to make it read easier, and did not change the content. Carry on. PAR 17:30, 2 August 2006 (UTC)

Hi PAR, sure the reformating is fine, even very welcome. I am not familiar with latec so I just didn't know how to write the equations neatly. As for the restoring I consider erasing the right thing to do since my original post might lead to confusion. If the Wiki-family prefers not to erase it I consent though. Remains that I think in this case the discussion title had better be changed, since it gives too strong an impression of something really being faulty in the main article (yeah, I sould have thought about that earlier), don't you think? PS. A question for an old fox; how do i get rid of the "you have new messages"-bar? Since this was a first for me I didn't create a personal login and it seems the IP is the server IP so anyone at work with me will get the message, which will lead to yet more confusion.

Thomas

Hi Thomas - Yes, it shouldn't be erased because its helpful to others who might read it and also its "policy" not to erase it because some discussions get pretty heated, and erasure of what one said is reprehensible and always wrong. I think we can get away with changing the title to "Planck's law is wrong?" with a question mark, which I will do. You get rid of the new messages bar by clicking on it. That should take you to the talk page, where you can answer the question. For example, after you wrote the above, I had a message bar, and now that I have clicked on it and replied, It will be gone. Why not get a personal login? You will avoid the confusion and be able to communicate with people more consistently. PAR 13:55, 3 August 2006 (UTC)

• Thanks so much for adding to Wayne, New York, Stepp-Wulf 01:45, 5 August 2006 (UTC).

Unspecified source for Image:Lenna.png

Thanks for uploading Image:Lenna.png. I notice the file's description page currently doesn't specify who created the content, so the copyright status is unclear. If you have not created this file yourself, then there needs to be a justification explaining why we have the right to use it on Wikipedia (see copyright tagging below). If you did not create the file yourself, then you need to specify where it was found, i.e., in most cases link to the website where it was taken from, and the terms of use for content from that page.

If the file also doesn't have a copyright tag, then one should be added. If you created/took the picture, audio, or video then the {{GFDL-self}} tag can be used to release it under the GFDL. If you believe the media meets the criteria at Wikipedia:Fair use, use a tag such as {{Non-free fair use in|article name}} or one of the other tags listed at Wikipedia:Image copyright tags#Fair_use. See Wikipedia:Image copyright tags for the full list of copyright tags that you can use.

If you have uploaded other files, consider checking that you have specified their source and tagged them, too. You can find a list of files you have uploaded by following this link. Unsourced and untagged images may be deleted one week after they have been uploaded, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you. howcheng {chat} 18:33, 29 August 2006 (UTC)

Abramowitz and Stegun - confusing situation

Hi PAR, your change to Orthogonal polynomials breaks the link to the Wikipedia article on A&S called Handbook of Mathematical Functions. Also, I know people use ISBNs historically, but there is a real Dover edition of this book which is available for purchase through Amazon for $24.39, but its ISBN is now gone! The only ISBN remaining is the hardcover edition that can only be purchased from the government, for $68.50. Would you consider reverting your change, or at least undoing these particular consequences? I agree that some of the bibliographic details are unclear. EdJohnston 05:30, 23 September 2006 (UTC)

Well I thought I was doing a good thing, eliminating older references in favor of new. I reverted it, but I'd like to get it right before changing other A&S references. PAR 02:07, 25 September 2006 (UTC)

All A&S references should be converted to a template, so that the layout can be centrally controlled. linas 03:22, 4 October 2006 (UTC)

Fourier function talk

Thank you for your positive attitude in your reply of September 13. I'm sorry that I don't have much time these days to follow up as intensively as one should who put a merge tag on an article. I think, however, that I found a better way to explain my motivation for the tag, and I just added it there. (I also replied to your question "How do the "significant structural inconsistencies" change this?" further up in the discussion.) — Sebastian (talk) 00:33, 24 September 2006 (UTC)

You mentioned Fourier Transform on Locally compact abelian Groups. Unfortunately I'm not familiar with this generalization. How many of the properties of the continues FT does it preserve? — Sebastian (talk) 22:07, 27 September 2006 (UTC)

I'm not familiar with it either. User:Thenub314 suggested it as a generalization which would cover all four cases. We should ask Thenub314 for clarification. PAR 03:05, 28 September 2006 (UTC)

Abramowitz & Stegun references

Please see my note on Talk:Orthogonal_polynomials

I see Ed Johnston has already paid you a visit :-) William Ackerman 21:52, 24 September 2006 (UTC)

In case you miss it above, I'll repeat myself: all A&S refs should be converted to a template, so that the style and layout can be centrally controlled. linas 03:25, 4 October 2006 (UTC)

That sounds like an excellent idea. Maybe I'll try to do it. I'm not an advanced template programmer, but I think I know what we need, and then a more advanced programmer can do it better. PAR 03:29, 4 October 2006 (UTC)

Polylog algos

Do you know of any papers that might describe fast algorithms for computing the polylog, in the general case? linas 03:25, 4 October 2006 (UTC)

No, I don't. I would search around the Mathematica website to begin with, because obviously they have implemented some algorithm. Also, the Wood reference on the polylogarithm article might be helpful. Wood was looking for a polylogarithm algorithm himself and this was what drove him to write that article - to condense the knowledge he had gained from a number of scattered sources, each with a piece of the puzzle. I had email conversations with him about his article, and he seemed to be very ready to help. You might try emailing him with this question. PAR 03:35, 4 October 2006 (UTC)

FWIW, I've been prompted to write An efficient algorithm for accelerating the convergence of oscillatory series, useful for computing the polylogarithm and Hurwitz zeta functions, which is now almost done. linas 04:49, 5 February 2007 (UTC)

Fitness landscape

Err, my delisting comment still seems to be on the talk page....? Homestarmy 19:15, 19 October 2006 (UTC)

Yup. Please see your talk page. Sorry about that. PAR 19:19, 19 October 2006 (UTC)

You deleted a lot from Black body

I noticed your edit http://en.wiki.x.io/w/index.php?title=Black_body&oldid=80573683 deleted an entire section and also deleted and moved around images. It was quite the major edit, but your edit sumary was simply "Link to Planckian locus." Was it all a mistake? JabberWok 03:37, 20 October 2006 (UTC)

YOW - All I can say is those are not my edits. I have no idea what happened there, none of those changes are familiar to me. All I did was rewrite a sentence in the introduction to link to the Planckian locus article. One of us should start from the version before "my" edit and reconstruct things. I can do that, or you can do that, whatever you want. PAR 14:43, 20 October 2006 (UTC)

I see you have done that - good. PAR 16:41, 20 October 2006 (UTC)

Leff's paper

Par, I've been digging into that thermodynamic entropy paper by Leff and in doing so I have been reading parts of the books he references. If you want to get a good presentation of the energy sharing, mixing, or spreading between quantized energy levels I would recommend that you get a copy of Kenneth Denbigh's The Principles of Chemical Equilibrium (originally published in 1955). The theory or argument starts on page 48, it has nice diagrams, and is argued and written 10x better than the Leff paper, which I have to say turns me off because it is presented in such a sloppy manner. He also uses Ralph Baierlein as a reference, but I have Baierlein's 2003 Thermal Physics, and it is not at all written like Leff's article. Baierlein's book is one of my favorites. It is well-written and full of atomic insight. This is all I can give you. To really dig into this issue would take a month's worth of reading. P.S. do you know how to make an S with a dot on it or an S with a triangle hat on it in math formula? Later: --Sadi Carnot 18:33, 5 November 2006 (UTC)

Hi - thanks for the reference, I will check it out. For the dot, I would do

${\dot {S}}$

but for the triangle, I don't know, the best I could do would be:

${\stackrel {\triangle }{S}}$

PAR 21:41, 5 November 2006 (UTC)

Thanks, then I'll add the following entropy balance equation for an open system, in which heat, work, and mass flows across the system boundary, i.e. according to Sandler's 1989 Chemical and Engineering Thermodynamics, 2nd Ed. I'll add it to the entropy article, with more comment and elaboration. I'll check the Wiki help (Math symbols ) page to see if someone knows the hat notation. Later: --Sadi Carnot 14:13, 6 November 2006 (UTC)

After looking at what you wrote, I think you want this:

${\hat {S}}$

PAR 21:36, 6 November 2006 (UTC)

Thanks, I'll change it. P.S. I'm kind of interested in your minimum potential energy principle endeavors, e.g. my notes. I think these two articles need to be grouped up into one. I’ve been keeping notes, whenever I find this principle in books. Out of time for today, talk later: --Sadi Carnot 01:31, 7 November 2006 (UTC)

They are two different, but related principles (which is not to say they shouldn't be merged). The minimum potential energy principle says (roughly) that at equilibrium, for a fixed total energy, potential energy minimizes, since this maximizes entropy. The minimum energy principle says that for a fixed entropy the total energy minimizes. PAR 05:03, 7 November 2006 (UTC)

Entropy balance equation for open systems

In chemical engineering, the principles of thermodynamics are commonly applied to "open systems", i.e. those in which heat, work, and mass flow across the system boundary. In a system in which there are flows of both heat (${\dot {S}}$) and work [(${\dot {W}}_{S}$) and ($P{\frac {dV}{dt}}$)] across the system boundaries, the heat flow, but not the work flow, causes a change in the entropy of the system. This rate of entropy change is ${\dot {S}}/T$, where T is the absolute thermodynamic temperature of the system at the point of the heat flow. If, in addition, there are mass flows across the system boundaries, the total entropy of the system will also change due to this convected flow. To derive, we start with the general balance equation for the change in any extensive quantity Θ in a thermodynamic system, which states that dΘ/dt, i.e. the rate of change of Θ in the system, equals the rate at which Θ enters the system at the boundaries, minus the rate at which Θ leaves the system across the system boundaries, plus the rate at which Θ is generated within the system. With respect to the rate of change with time of the extensive quantity entropy S, this gives:

${\frac {dS}{dt}}=\sum _{k=1}^{K}{\dot {M}}_{k}{\stackrel {\triangle }{S}}_{k}+{\frac {\dot {Q}}{T}}+{\dot {S}}_{gen}$

where

$\sum _{k=1}^{K}{\dot {M}}_{k}{\stackrel {\triangle }{S}}_{k}$ = the net rate of entropy flow due to the flows of mass into and out of the system (where ${\stackrel {\triangle }{S}}$ = entropy per unit mass).

${\frac {\partial {\dot {Q}}}{\partial T}}$ = the rate of entropy flow due to the flow of heat across the system boundary.

${\dot {S}}_{gen}$ = the rate of internal generation of entropy within the system.

Note, also, that if there are multiple heat flows, the term ${\dot {Q}}/T$ is to be replaced by $\sum {\dot {Q}}_{j}/T_{j}$, where ${\dot {Q}}_{j}$ is the heat flow and $T_{j}$ is the temperature at the jth heat flow port into the system.

Entropy and life

Par, someone recently started this article as a stub on the entropy page; I beefed it up and moved it to its own page. Have any contributions for this page? I see that you are interested in the potential energy minimization principle. I am interested in this as well; however, I think the page needs to be moved to a shorter title and the entropy maximization principle needs to go to a non-information theory page with a discussion of the second law. And this: principle of minimum energy needs to be merged somewhere. Any comments? Later: --Sadi Carnot 13:07, 7 November 2006 (UTC)

Hi Sadi - I will look at the "entropy and life" page. Regarding the principles, they all follow from the first and second laws -

• Principle of maximum entropy (call it PME) - Yes, this is a probability theory type page and is not equivalent to the second law. I think it should be renamed "Principle of maximum entropy (probability)" or something, and a disambiguation should point to the second law page for the thermodynamic principle. However, thermodynamic entropy is a type of information entropy so I think the PME page is a thermodynamically relevant page. I don't think a "principle of maximum entropy (thermo)" page is needed, since this is covered by the second law page. The second law page should reference the PME page with a suitable explanation of relevance.
• principle of minimum energy - This is a restatement of the second law for closed systems instead of isolated systems. (closed system = no particle transfer, possible energy transfer, isolated system = no particle transfer, no energy transfer). So a symmetric pair of statements is:
  • entropy max principle = closed system, constant energy means the entropy is maximized.
  • energy min principle = closed system, constant entropy means the energy is minimized.

The energy min principle is not an independent priciple, but statement of the equilibrium condition for a closed, constant entropy system. It is derivable from the first and second law but it is fully equivalent to the second law. Using the first law and the energy minimum principle, the second law may be derived.

• potential energy minimization principle This is subordinate to the second law - it is a consequence of the second law for a particular situation. Unlike the energy minimum principle, it does not hold for closed, constant entropy systems, but rather, like the second law, it holds for isolated (closed, constant energy) systems. It says that for isolated systems, entropy is maximized when as much energy as possible exists as heat energy rather than potential energy, and therefore minimum potential energy is the equilibrium state.

As far as pages are concerned, I believe the energy minimum principle is a "strong" statement, while the potential energy minimum principle is a "weaker" statement. If they are to be merged, I would say they would be merged into the second law page. I would favor the potential energy minimum page be merged into the second law page before the energy minimum page, since the energy minimum principle is a stronger statement. PAR 15:33, 7 November 2006 (UTC)

Yes, this looks like a good start, yet this whole group looks like it needs a good cleaning, regrouping, and reorganizing. I'm pretty sure that Clausius is the source of the maximum entropy principle and that Gibbs is the source of the minimum (potential) energy principle. But, the minimum energy principle is a big topic; Gibbs switches around between internal energy, enthalpy, free energy, and others using this old notation, which is difficult to follow. We'll have to work on cleaning and sourcing these as time goes on; over the next two months or so, however, I am going to try to cut back a Wikipedia a bit so that I can finish a new book I'm working on. P.S. did you see this. Later: --Sadi Carnot 01:01, 8 November 2006 (UTC)

Information entropy definitions

Hi par, I see that you want the "information entropy" definitions moved off the page. There was an edit conflict when you did this. Could you see how they fit now with the new material I added? I think that trying to pigeon hole this page to focus predominantly on thermodynamic entropy, to the exclusion of other types of entropy, will be difficult. Any comments? --Sadi Carnot 16:29, 21 November 2006 (UTC)

Hi Sadi - I moved the "information entropy" subsection back to the "approaches" section because I strongly believe that the first section should be devoted to non-controversial descriptions and definitions of entropy. I expanded what was "information theory" section and renamed it "similarities between the two" in contrast to the section "differences between the two". This could be the repository of successively refined postions pro and con.

I also believe that there should be a separate page devoted to thermodynamic entropy. A page that is devoted to all types of entropy should not try to explain thermodynamic entropy in any detail, but rather should point to a thermo entropy page, otherwise that page will be too long, and for the person who wants to study a particular type of entropy, (thermo or not) it will be cluttered with irrelevant stuff. Now, how this is implemented, I am not too concerned. We could have an "Entropy (thermodynamics)" page and an "Entropy" page, or we could leave it as it is. PAR 18:14, 21 November 2006 (UTC)

As to a separate page on "thermodynamic entropy, we already have this page: entropy (thermodynamic views)?

Well, what do you think? I haven't paid any attention to that article, but maybe all the thermodynamic details should go to that page. We should take this discussion to the Entropy talk page, and make the suggestion. PAR 04:21, 22 November 2006 (UTC)

I'm taking a break from all the entropy pages for a while; I'll have to get back to you. Later: --Sadi Carnot 05:28, 28 November 2006 (UTC)

Fourier transform

Can you take a look at this comment ? I would like to get your input. Abecedare 03:50, 28 November 2006 (UTC)

\equiv

Thank you for offering your help! I replied to your question on WT:WPM, but no need to look it up, here you go again: The list is Wikipedia talk:WikiProject Mathematics/equivlist - simply delete the bullet points for articles you completed. — Sebastian (talk) 19:35, 28 November 2006 (UTC)

New Thermodynamics template.

Have a good look at this; it looks quite good, i think. Maybe User:JCraw will make changes to it? James S 01:16, 29 November 2006 (UTC)

Hi - WAY too large, but otherwise kind of neat. The font size should be less than or equal to the text size for the body of the article. These navigational templates should not be obtrusive - they should not appear more important than the text. Also, this kind of thing should be discussed by more editors than just us. I will try to bring some more people in on this. PAR 06:28, 29 November 2006 (UTC)

I have moved this discussion to the talk page of the Thermodynamic equations template. Lets continue it there. PAR 06:45, 29 November 2006 (UTC)

Now, that new template is excellent. I think the one with the beakers on it is better, but User:JCraw did a great job with it. Shall we replace it? James S 17:22, 29 November 2006 (UTC)

Created one for the formulae. Hope it's okay. James S 18:12, 29 November 2006 (UTC)

Thermodynamic equations
Internal Energy	$U(S,V)$
Helmholtz free energy	$A(T,V)=U-TS$
Enthalpy	$H(S,P)=U+PV$
Gibbs free energy	$G(T,P)=U+PV-TS$

Two points - this template should be labelled "Thermodynamic potentials" not "Thermodynamic equations" and second - lets move this discussion to the talk page for Thermodynamic potentials which is where it really should be.

Welativity

This is positively hysterical. It seems someone has already taken care of it, however. Thanks kindly for the heads-up. — Dan | talk 03:45, 4 December 2006 (UTC)

redirect at real gas

Why did you change the redirect at real gas to gas from ideal gas? The two are very different articles, and you didn't even leave an edit comment. ... aa:talk 01:48, 9 December 2006 (UTC)

The quick answer is because a real gas is not an ideal gas. Shouldn't "real gas" point to an article which deals with actual gases and their deviations from any idealized model? I looked at the "gas" article and thought that was about the best article I could find, without beginning a new article entitled "real gas". PAR 03:50, 9 December 2006 (UTC)

Well, this is why I asked. I was rather hoping you would explain the difference. The gas article doesn't seem to address what a "real" gas is versus an.. unnamed gas? As you clearly understand the subject more than I, I'm glad you made the call. That's the only reason I ask, and I hope you didn't infer any hostility on my part. Thanks, ... aa:talk 22:32, 9 December 2006 (UTC)

Sure, no problem. PAR 22:49, 9 December 2006 (UTC)

WP:ELAC

Hi PAR, want to join a new project-group I recently started the WP:Extra-Long Article Committee? You could help keep the group posted on or help projects related to the division of extra-long science articles (or anything along these lines) from time to time? Talk later: --Sadi Carnot 19:02, 9 December 2006 (UTC)

Sure, sounds like a good idea. PAR 19:56, 9 December 2006 (UTC)

ELAC welcome

Hi PAR, thanks for joining the Extra-Long Article Committee. Here’s a useful site map for you:

{{ELAC site map}}

Your inputs are always good. Feel free to contribute any way you want. No rush on this project; it's more of a chip-away a little at a time kind of project. Thanks, talk soon: --Sadi Carnot 18:50, 9 December 2006 (UTC)

Confluent hypergeometric function

I note you added text to identify two solutions as Kummer's and Whittaker's. This is not the usage that A&S uses; I'm wondering where you are getting these two names from? linas 00:49, 11 December 2006 (UTC)

My mistake - I will fix it. PAR 01:03, 11 December 2006 (UTC)

Hi Linas - I fixed it, but the Confluent hypergeometric function is not finished. It only deals with Kummer's functions M and U but not Whittaker's functions. The text follows A&S except for the "first kind" and "second kind" names which I took from Mathworld. PAR 02:14, 11 December 2006 (UTC)