User talk:Petergans/Archive 1

Welcome!

Hello, Petergans, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

• The five pillars of Wikipedia
• How to edit a page
• Help pages
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• How to write a great article
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I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or ask your question and then place {{helpme}} after the question on your talk page. Again, welcome!  Nimur 09:11, 19 March 2007 (UTC)

Articles

Hi Peter. It looks like you put two really good articles on your user page. Do you want me to split them up into subpages for you? That way you can have both drafts in your userspace to edit as you please. --HappyCamper 18:36, 14 April 2007 (UTC)

Hmm...what I mean is that the edits to your user page contain two articles. One on numerical smoothing (dated March 26) [1], and your current rewrite [2]. The user page isn't usually used this way, so I wanted to fix it up - but I didn't want to surprise you either. I was thinking of putting them in User:Petergans/Numerical differentiation and User:Petergans/Molecular vibration and have links point to them from your userpage. --HappyCamper 23:37, 14 April 2007 (UTC)

I can see the two articles by looking at page histories. I put your draft at Talk:Molecular vibration/draft. Also, check out Wikipedia:About the Sandbox. In the future, you can put drafts in your "sandbox" in addition to putting drafts on the article talk page. Some Wikipedians like to write articles in their sandbox first, and then move them to where there are supposed to be when it is time to publish. --HappyCamper 18:42, 15 April 2007 (UTC)

I've never come across an HTML to Wiki translator, but I'll ask and see if anything interesting comes up. Do you plan on importing material from webpages you own? Some people find it easiest to just cut and paste, but that can be quite tedious. Just make sure the material can be licensed under the GFDL (just like the rest of Wikipedia). I don't understand what you mean by having difficulties finding information...Maybe our Wikipedia:Searching page might be useful? In particular, take a look at the section about using Google. If you prepend "site:en.wikipedia.org" before your search items, it will do a search within Wikipedia's domain. There are other editing and convenience tricks on Wikipedia, but I'm trying to hold back a little so that I don't overwhelm you with too much new information.

I think molecular vibration is pretty well written - infinitely better than what the article used to be! Thank you so much for sharing your expertise here. With the exception of a few esoteric wikifying edits, the article will probably be quite stable...probably comparable to polythiophene. Image creation is quite sporadic, so I don't know when a labeled ethylene image will be made. I hope it comes soon though, that would be really nice. By the way, feel free to add to Template:Chemical equilibrium constants (for want of a better name!). If it's useful, we can use the template as a navigational aid for all the related concepts. Cheers, --HappyCamper 23:04, 22 April 2007 (UTC)

I removed that note about entropy of mixing...As for the rewrite, we should talk about this over at Talk:Chemical equilibrium since these articles have quite an extensive edit history. On another note, I moved the template to Template:Chemical equilibria. --HappyCamper 16:41, 24 April 2007 (UTC)

Yes, I think your idea is best. Click on this link here to start --> /draft . Probably better to write it in that spot instead of on the article for now. --HappyCamper 00:32, 25 April 2007 (UTC)

Hi Peter - Somebody gave me a link to a Word to MediaWiki converter: [3]. I've never experimented with it before, but it might work. As for item two, I don't think there is an editorial standard on Wikipedia yet. Go with what's easiest to use for now. As for the templates, feel free to edit them. There is this policy which governs this. Personally, I'm aiming to be even more ambitious and make a navigational template similar to Template:Physics-footer. It would be really great to organize all the chemistry articles in this way. --HappyCamper 19:10, 26 April 2007 (UTC)

Draft

Hi Peter - I thought it might be better to make a new section here since we'll be talking mostly about your draft. I'm glad the Word macro worked out well. I don't think it's possible to render the math equations with smaller font. Generally, if the equation is "sufficiently complicated", it will be rendered with the larger TeX font. If you click on "my preferences" in the top right hand corner of your screen, there might be a better local setting for your computer. The full path to your draft is User talk:Petergans/draft, so [[User talk:Petergans/draft]] will refer to it. The [[/draft]] notation is just a shortcut way of referring to subpages. In other words, if you were editing on say, Talk:Equilibrium constant, the [[/draft]] page would actually refer to [[Talk:Equilibrium constant/draft]]. --HappyCamper 04:02, 29 April 2007 (UTC)

Articles, merging...

Thanks for your message. I have to keep this response brief for now, but I'll come back with more when I get the chance to.

• In short, I like your ideas, but what you are proposing is akin to "wiki-brain-surgery". Normally, I would advocate being bold and simply do what you think is best, but this time, it's a little different, and things are probably going to move a little slower than usual. Perhaps it's "Wikipedian culture" or "Wikipedian bureaucracy". You were able to replace molecular vibration much easier because nobody visited that page for ages, and everyone was in agreement that your version was better.
• Cutting and pasting is avoided on Wikipedia - it's tempting, quick, and easy, but it's generally not done. More details here: Wikipedia:Merging and moving pages. Boils down to keeping page histories intact so that individual authorship is clear.
• As for deletion, see Wikipedia:Deletion policy. If you want to delete your draft, put {{db|some reason}} at the top of it. This is known as "speedy deletion". An administrator will come by and decide whether to follow through with your request for deletion.
• My hunch is that it would be better to put your article in a separate place (Thermodynamics of equilibrium perhaps?) for now, and "publish" it in that way. Avoids all the complexities of this merging process entirely. If you decide this is better, move the page to its new location. Then, request a speedy deletion of the redirect that is created.
• If you want to make changes to existing articles, save often, and make changes incrementally. Use edit summaries, so that the page history summarizes your train of thought. This is preferable to replacing it entirely with a new article, especially if the article has had a long history on Wikipedia. As much as editors are supposed to be detached from their edits, this is often not the case, and you will see people care deeply about major changes to "their" edits or articles. This is often a double-edged sword, but I hope this gives you some idea behind some of the dynamics that occurs on this site.
• Can I safely say that the Wikipedia bug has bitten you? :-) When you have an inclination to click on that "edit this page" button fix errors on Wikipedia, well, I'd say you're pretty much a Wikipedian now! Anyway, all this discussion about articles is heavy stuff. Let me invite you to our cherished archive of "bad jokes and other deleted nonsense". --HappyCamper 20:04, 5 May 2007 (UTC)

HD

I've added some comments to your help desk question. - Mgm|^(talk) 22:31, 8 May 2007 (UTC)

• While I agree with the general concept of having laymen involved in article writing, I also believe that having them add material without saying where it came from (which is probably the cause of the error in irreversible reaction) is not a good idea. I need some more time to respond to your post - talk to you later. - Mgm|^(talk) 09:42, 9 May 2007 (UTC)

Redirects

It's probably easiest to do this by example. Click on Agamenon (which is a misspelling). It will redirect you to the correct article. In the upper left hand corner, you should see a tiny blue link that says "(Redirected from Agamenon)". It should be right under the article title. If you click on this page, you will get to go back to the original location of the redirect - and naturally, you'll be able to edit this page. --HappyCamper 16:29, 9 May 2007 (UTC)

Helpme on draft

If you're talking about the interwiki links on the bottom of the article, they work differently in the user space than they do in the mainspace. They're formated correctly, and when the article is moved to mainspace they will work as expected. I'll remove the helpme, but please put it back if this does not answer your question. Cheers, ➪HiDrNick! 13:30, 10 May 2007 (UTC)

Re:Chemical equilibrium

The problem is, how to present the subject to the general reader and at the same time not make erroneous simplifications.

• You saw it in Molecular Hamiltonian and there's multiple other instances, we shouldn't be too technical, but a lot of articles are simply because the writers have a different idea of what is technical than the average reader. It's a problem and the only way to address it is to rewrite the articles affected. I can't find the specific page yet, but what I've read is to write with college graduates in mind.

Incidentally I did not cite Atkins because his treatment (I only have the first edition!) does not go far enough on the activity issue, or on multiple equilibria.

• You'll be glad to know he does now. That, or what I learned was covered in one of my biochemistry books.

I am strongly opposed to deriving the equilibrium concept from kinetics as, once learnt, this (historical) derivation has to be unlearnt and replaced by the thermodynamic derivation. The original mass action of Guldberg and Waage was incorrect in so far as rate laws do not necessarily follow stoichiometry, whereas equilibrium constants do so. I believe that kinetics is pretty much irrelevant to equilibrium, so I banished it from my draft.

• You may be personally opposed to it, but people will have learned about equilibriums through kinetics. It's better to include it as a precursor and explain what's wrong about it.

The other thing which troubles me is the Wikipedia notion of concensus. In a printed encyclopedia the articles are written by acknowledged experts, but in Wiki it seems that experts are equal to laymen. I have more than 30 years experience of research and teaching in equilibrium chemistry at Leeds University home page.

• At times I can be frustrated by that too. Laymen are subject to the same rules as anyone else. Anything they post should be backed up by a reliable source. The reliable sources will back up the stuff you've written, so I doubt much untruths could get through. Most of the inaccuracies occur when writers write from memory or hearsay or cite erronous webpages that try to be helpful or course readers that happen to have an error. Keeping good articles in a correct state is a constant struggle on any article, but the developers are working on a technical solution for that.

I hope I've helped a bit. One thing about the draft. 2 citations in an article this size is too little. See if you can use any of the general reading entries as a reference and make sure you provide a citation to back up the definition you give in the very first line. Also "as the reaction is driven to the left" may need a more overt wording explaining exactly which particles react to become what to restore the balance. - Mgm|^(talk) 10:05, 11 May 2007 (UTC)

[HF_2]^-

So you removed my square brackets. I have to say that I disagree with you, and just because thy're not in the hydronium article doesn't make it right. Maybe I'll sneak them back in when you're not looking.

As for [HF₂]^- being a three centre, two electron bond... Thinking about it, I think it's actually a three centre, four-electron bond, as the non-bonding three centre MO is filled as well as the bonding one. I've not come across such a thing before though; I'll look it up tomorrow. If you think about it as HF hydrogen bonded to F^-, it's obvious where the four electrons come from. Chris 17:59, 14 May 2007 (UTC)

• Having just written that, I find we have actually have an article on three centre, four electron bonds, so I've changed the link to that instead! Chris 18:02, 14 May 2007 (UTC)

• • I found a more recent article and added that to the references for three-center four-electron bonding. Chris 12:21, 15 May 2007 (UTC)

Greenwood and Earnshaw

Thanks for your message. I saw that you were at Leeds and figured you might know them. I remember the late great Ron Snaith telling me once that one of them (I forget which) was his father in law, and that I had to buy the book because he needed the money :)

I changed the bonding in [HF₂]^- to 3c-4e; the references there are very clear that this is the correct desciption.

Incidentally, I think this : ⇌ looks better than this: $\rightleftharpoons$

Cheers, Chris 20:21, 14 May 2007 (UTC)

reponse left to your Request for Feedback

I left a response at Wikipedia:Requests for feedback to your question on Reversable Chemical Processes. Please read it over and let me know if it makes sense. --Jayron32|talk|contribs 05:18, 15 May 2007 (UTC)

Nice to see inorganic chemists!

It's always a joy to see other inorganic chemists out there; so many people tend to go towards organic chemistry as i have in the past, but find myself drawn more to inorganic and physical :-). Thanks for coming to wikipedia, hope you decide to edit lots here! ♥♥ ΜÏΠЄSΓRΘΠ€ ♥♥ ^{slurp me!} 20:16, 23 May 2007 (UTC)

Equilibrium

I'm sorry for the lack of response on my part, but I have been busy with other things. You could ask the nice guy who posted above me to help out, but if that doesn't work, I suggest talking to the Wikipedia:Mediation Cabal. If the person in question keeps reverting without any sort of discussion, you're doing nothing wrong in reverting him as long as you try to initiate discussion. - Mgm|^(talk) 08:25, 29 May 2007 (UTC)

I just wanted to add an image to the article and added whatever was available. If you can find a better illustration, feel free to add it. It is also a characteristic feature of Wikipedia that expertise and qualifications do not matter. This is our blessing and curse, make what you will of it. Einsteine himself wouldn't have been allowed to edit according to his will if he did not put in references. Any objection you have to the article in its current state should be discussed in the talk page with reason and references instead of flaunting your credentials. Loom91 07:55, 1 June 2007 (UTC)

You are right, it is not correct to say time-derivative. I was fully aware that it was a mistake, but I thought it would simplify the writing. In hindsight, it was a mistake. I've corrected it. Loom91 20:54, 4 June 2007 (UTC)

Haber process; entropy of mixing

After some delay due to travel I have replied to your questions in my talk page. --Itub 07:14, 5 June 2007 (UTC)

Your message.

If you want attention from an administrator, please ask for attention from another administrator. At the moment I am too busy to help you out. WP:AN or WP:ANI should be helpful. - Mgm|^(talk) 17:24, 20 June 2007 (UTC)

Activity coefficients

Thank you for your contributions to the Activity coefficient article; it is much the better for it. I think, however, I have espied an error.

You wrote, "As concentrations tends to zero, activity coefficients tend to one, so in very dilute solution, activity is equal to concentration." (I have taken the liberty of adding two commas).

Shouldn't it instead read "As concentrations tend to one..."? Since according to the equation,

$\mu _{B}=\mu _{B}^{\ominus }+RT\ln x_{B}\gamma _{B}\,$,

if $x_{B}$ were zero, $lnx_{B}$ would be -∞. One the other hand, if $x_{B}$ referred to the mole ratio of the solvent instead of a solute, $x_{B}=1$ would correspond to a dilute solution. This would give the desired result

$\mu _{B}=\mu _{B}^{\ominus }$.

Or am I misunderstanding something?

-Wiccan Quagga 10:05, 10 November 2007 (UTC)

Upon further consideration, I realize that it's not whether a particular substance is a solute or a solvent that counts--the distinction fades to nothing when both substances are infinitely miscible--but whether or not they are pure. I'm going to go ahead and change the article to reflect this. Please feel free to revert me if you think I'm making a mistake.

-Wiccan Quagga 10:56, 10 November 2007 (UTC)

I feel that my last statement requires a clarification. There is at least one property that does depend on whether a substance is a "solute" or a "solvent": the activity coefficient of the substance that is nearly pure approaches one; the activity coefficient of the substance that is greatly diluted does not. Sorry to clutter up your talk page with my ramblings :)

-Wiccan Quagga 11:19, 10 November 2007 (UTC)

The assertion that activity coefficients go to one was based originally on the Debye-Hückel limiting law used to derive the mean activity coefficient of an ionic substance.

$\log \gamma _{\pm }=-\mid z_{+}z_{-}\mid AI^{1/2}$

As the ionic strength, I, goes to zero, $\log \gamma _{\pm }$ goes to zero so $\gamma _{\pm }$ goes to one. Although the Debye-Hückel law strictly only applies to ionic substances, it is clear that activity coefficients deviate from unity because the species concerned interact with each other in some way, so they should always approach one in very dilute solutions.Petergans 11:42, 10 November 2007 (UTC)

ls proposals

Hi, I just wanted to thank you for suggesting reorgaizing the least squares related articles and in doing it in such a smart way (on a talk page, and giving people lots of time to respond) I disagree with Oleg's comment on your push for consistent notation, I think it's great that you are thinking of the project as a series of articles, not just a few here and there. Pdbailey (talk) 16:49, 24 January 2008 (UTC)

The question of notation is rather secondary though. A bigger issue is that the new linear least squares article is harder to understand than the old one. Oleg Alexandrov (talk) 04:17, 1 February 2008 (UTC)

Your name has been mentioned at Wikipedia talk:WikiProject Mathematics

Hello Petergans! A number of mathematics editors have been discussing the Least squares article. You are welcome to add your own comments there. EdJohnston (talk) 18:29, 31 January 2008 (UTC)

Note of move

I moved User:Petergans/b/sandbox to Non-linear least squares. Thank you for the fine work. However, I would disagree with merging Gauss-Newton algorithm to it, and other people seem to echo my sentiments that such a merge would make things harder to understand.

I also further commented at Wikipedia talk:WikiProject Mathematics. My suggestion there is that we attempt to make linear least squares easier to understand before attempting further rewrites.

You can reply here if you have comments. Cheers, Oleg Alexandrov (talk) 04:16, 1 February 2008 (UTC)

Linear least squares

I see that you are still working on this article in your sandbox. I think if you want to contribute to that article you should edit the Linear least squares article directly rather than keeping a parallel version in your sandbox, and we should discuss any differences. Wonder what you think. You can reply here. Thanks. Oleg Alexandrov (talk) 04:41, 8 February 2008 (UTC)

The reason for doing this is is that I have been trying to achieve consistency between least squares, linear least squares, non-linear least squares, Gauss-Newton algorithm and eventually some of the related articles. This was the purpose outlined in my major proposal. I know you don't approve of "grand projects", but I see this rather as a tidying up operation. If I had worked on the article directly some of the changes would not have made sense.

Regarding linear least squares, I have said that some of your recent edits were unacceptable. This is very strong criticism and I stick by it. To me your latest definitions section is very hard to understand, even without norms. My new version uses simple algebra which should be much more accessible to non-mathematicians.

As it happens I am going live today with all four revised articles, with a note of explanation on Talk:Least squares. I am suggesting that general comments be made there, but comments specific to each article be made on the respective talk pages, where I will also place notes.

Incidentally this is the dictionary definition of objectionable: unpleasant, offensive or repugnant. I know you meant to imply that it was something to which you objected, and I let it pass as English is not your mother tongue, but I thought you should know.

Petergans (talk) 09:09, 8 February 2008 (UTC)

I commented at Wikipedia_talk:WikiProject_Mathematics#Least_squares: implementation of proposal. You basically refused all discussion and went ahead with what you think was best at linear least squares. Such strategy is rude to say the least, and as I said earlier will result on wasted effort on all sides. Oleg Alexandrov (talk) —Preceding comment was added at 15:44, 8 February 2008 (UTC)

Gauss-Newton

I wrote a comment on the rewrite of that article at Talk:Gauss-Newton algorithm#Response to rewrite. Oleg Alexandrov (talk) 03:25, 9 February 2008 (UTC)

Hemoglobin O2 binding

The section about the oxidation state of iron in oxyhaemoglobin is wrong. It is now known that it is low-spin Fe(II). See Greenwood and Earshaw, Chemistry of the Elements 2nd edition, pp 1099-1100. The key point is that in deoxy-Hb the high-spin Fe(II) is too large to enter the plane of the porphirin ring (Figure 25.7) but when oxygen binds the low-spin Fe(II) enters the plane as it is small enough. The paramagnetism of O₂ is destroyed because the Fe-O₂ angle is 120^o, so the pi-star orbitals are no longer doubly degenerate.

I'm not a biochemist, so I hesitate to edit the article myself.Petergans 09:56, 11 May 2007 (UTC)

I made the same mistake in originally fleshing out this section. Apparently the old classic crystal field theory view of the iron pi-star orbitals being forced to give up their electrons into low spin pairs when O2 enters the picture, is wrong. Fe(III) when present in free hemoglobin won't bind oxygen, but oddly enough X-ray spectrocopy and IR show that iron in oxygenated hemoglobin actually is Fe(III), and the O2 bond had elongated enough that it's really a bond with order 3/2, i.e. it is superoxide .O2-. So the (surprising) fact is that O2 binding to hemoglobin involves a (temporary) partial oxidation of iron to Fe(III) and reduction of O2 to .O2-. Basically about one electron gets temporarily transferred in a charge-transfer complex (of course you realized that electrons often don't get transfered exactly, but only approximately, since these bonds have some covalent character). Anyway, that's the modern picture. It's the simple loss of an electron which allows the iron to shrink and drop back into the ring plane, not pairing up of its previous electrons into a more compact configuration.SBHarris 18:40, 11 February 2008 (UTC)

Linear regression Example: heights and weights

Sorry but I'd prefer not to enable email – i wouldn't mind receiving an email from you, but I don't want anyone on wikipedia to be able to email me. I'd rather conduct conversations on talk pages (whether article or user - decided to move this to your User talk page as it seems to be a 2-party conversation at the moment). I think something's wrong with your regression results. It could just be the units. But in results of the last model in the example (without the linear term in height) the coefficient of x² is clearly inconsistent with the graph. I've just rerun the model in my favourite statistical package (Stata) and got this:

. regress weight height2
 
    Source |       SS       df       MS              Number of obs =      15
-----------+------------------------------           F(  1,    13) = 2208.52
     Model |  689.315143     1  689.315143           Prob > F      =  0.0000
  Residual |  4.05750798    13  .312115998           R-squared     =  0.9941
-----------+------------------------------           Adj R-squared =  0.9937
     Total |  693.372651    14  49.5266179           Root MSE      =  .55867
 
----------------------------------------------------------------------------
    weight |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-----------+----------------------------------------------------------------
   height2 |   18.60872   .3959729    46.99   0.000     17.75327    19.46416
     _cons |   11.14818   1.093288    10.20   0.000     8.786274    13.51009
----------------------------------------------------------------------------

This appears more consistent with the graph. Qwfp (talk) 20:24, 2 March 2008 (UTC)

I'm not familiar with stata, so I've put the spreadsheet at http://www.hyperquad.co.uk/Downloads.htm. I hope you can spot the error. I'll have another look at it tomorrow. Petergans (talk) 23:16, 2 March 2008 (UTC)

The mystery is resolved. Your results relate to the model $y=\beta _{0}+\beta _{1}h^{2}$: I rejected this model because the plot of residuals vs ht² show a clear systematic. My second model is $y=\beta _{0}+\beta _{1}h^{4}$, but the plots have ht² on the x-axis. I did this because the second parameter in the first model came out as probably zero. The fit is remarkably good!

In terms of BMI the second plot may not make much sense, but I know nothing about BMI etc. Maybe you can suggest some improvement. Petergans (talk) 07:43, 3 March 2008 (UTC)

My apologies, I misread the article, or didn't take in that x, the is the height squared. However I doubt I'd be the only one to make this error. Squaring a variable which is itself defined as the square of a physical quantity is likely to get a bit confusing. To be honest I'm rather going off the use of this example data set here at all, as it seems to bring up too many distractions from the main points that need illustrating. I've played around with it a bit more now and I agree that a regression of weight on (height)^4 gives a good fit, but it seems that a regression of 1/weight on height is just as good a fit! But all this is almost a better illustration for the data transformation article – I think it's getting too distracting here. Qwfp (talk) 11:38, 3 March 2008 (UTC)

I agree, it's not an ideal illustration. The motivation for plotting with ht² on the x-axis was to illustrate the fact that w/ht² is not constant, but the variable choice is potentially confusing. The model y = a + b ht+ c ht² is also adequate, as was the original cubic. Can you suggest a better data set? We need a system for which there is a good reason to expect that a quadratic will fit the data. Petergans (talk) 17:50, 3 March 2008 (UTC)

Do we? Why? I can see the need for an example that's not simple linear regression. But it could have two separate covariates, and in some ways that's less confusing. I guess one advantage of a quadratic in one variable is that it's easier to graph though, in which case one good reason for using a quadratic is to fit a maximum or minimum, No transformation is ever going to turn a min or max into a straight line for one thing. I don't have any example data sets that spring to mind, but there are lots of publicly-available data sets on the web. Statsci.org has a large list of such, if you have time to browse. Qwfp (talk) 23:14, 3 March 2008 (UTC)

Couldn't find anything useful there, so I've finally settled a quadratic model $y=\beta _{0}+\beta _{1}ht+\beta _{2}ht^{2}$. That's me done with this article. From now on it's up to others to improve it. Many thanks for your correspondence, it has been really useful. Petergans (talk) 15:08, 4 March 2008 (UTC) /* Linear regression Example: heights and weights */ ::I had a quick look and that's certainly clearer. I appreciate all the work you've put into this article. Regards, Qwfp (talk) 17:21, 4 March 2008 (UTC)

Linear Regression: mean and predicted response

Check out what I've put in the talk page as descriptions of the mean and predicted response. I'm sure the language can be refined somewhat, but it explains the concepts and gives the start and end of the derivation :) Velocidex (talk) 04:07, 11 March 2008 (UTC)

Gauss-Newton

I wonder if you have any comments regarding my comment at Talk:Gauss-Newton algorithm. I have my own proposal for a rewrite, but I wonder what you will say first. Thanks. Oleg Alexandrov (talk) 02:28, 12 March 2008 (UTC)

Probability and statistics sub-project?

Dear Peter, I recently proposed starting a "probability and statistics" sub-project (aka task force or work group) of WikiProject Maths and was wondering if you'd be interested in participating. If so, please add your name and any comments at WP:WikiProject Council/Proposals#Probability and statistics. Regards, Qwfp (talk) 21:57, 12 March 2008 (UTC)

More on Gauss-Newton

Peter, I wonder if you could comment on the recent discussion on Gauss-Newton. What you've been claiming about the data-fitting application having better convergence properties is wrong, the algorithm can fail even for data fitting, and the second derivative of data-fitting residuals may not be zero even at the minimum.

The plan is to merge the two sections on convergence, as the properties of the algorithm are the same in data fitting as in the general case. Please state your objections there. Oleg Alexandrov (talk) 15:23, 17 March 2008 (UTC)

Hold on ADC edits

Hi Peter, we seem to have made large edits simultaneously on ADC. I'm currently in the process of resolving the edit conflict by integrating my changes into your version, please hold until my next edit save. It shouldn't take more than 10 or 15 minutes. EagleFalconn (talk) 14:08, 23 July 2008 (UTC)

Follow up question to this: In the new lead you use pK frequently when discussing applications. Should this remain pK or for the sake of consistancy within the article, is it correct to change those to pKa? EagleFalconn (talk) 14:14, 23 July 2008 (UTC)

Featured Article Candidate for pKa

Howdy, I'm looking at listing Acid Dissociation Constant on WP:FAC. Any reason for me to wait? EagleFalconn (talk) 16:54, 4 August 2008 (UTC)

Image copyright problem with Image:Citric acid speciation.png

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Chemistry books

I mean this in the best possible way, but out of curiosity do you just have a library of relatively old chemistry books sitting around in your office or at home? Every time you reference a book it seems to come from the pre-1980s, and I'm curious where you're finding them. EagleFalconn (talk) 13:51, 8 August 2008 (UTC)

I've got no problem with old books -- I'm frequently dissatisfied with a lot of my textbooks in school because they focus on pictures instead of rigor. Prime example would be my physical chemistry book...too afraid to show me an integral, so it uses 5 paragraphs instead. I was just curious in general. EagleFalconn (talk) 14:08, 8 August 2008 (UTC)

Regarding Scifinder access at home, while you're at the library you might want to speak to the librarian about it. At Purdue, we use a program called Citrix which allow us to login to the library servers and remotely use SciFinder. It might be worth seeing if Leeds has something similar. The reason Purdue has it is because SciFinder use is so expensive that its cheaper to offer this remote service and simply restrict the number of people who can use it at any given time than it is to try some other distributed method. Have a good weekend. EagleFalconn (talk) 14:54, 8 August 2008 (UTC)

Hi Petergans

I have a little crazy question. I´m a german student and I have to write an english abstract about my work with FTIR. The problem is that I don´t know a native speaker to read it and my english is only enough to communicate. I saw you comment the english article about FTIR and so I pluck up my courage and ask you. It is half a page, so I perhaps could place it here. About help I would be VERY greatful!!! Claudia --80.132.234.231 (talk) 23:19, 27 September 2008 (UTC)

This is not a matter for Wikipedia. Contact me by e-mail, address at my site. Petergans (talk) 12:46, 28 September 2008 (UTC)

Duplicate Image:Phosphoric2.png

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Equilibrium symbol

There is some discussion at Wikipedia talk:Accessibility#Equilibrium_symbol that you may find of interest. --Itub (talk) 15:53, 17 October 2008 (UTC)

Update on ADC

Peter, I was about to update my comments at Wikipedia:Featured article candidates/Acid dissociation constant when I noticed that Sandy had just archived it, so it appears it will be not be promoted this time around. I'll add my responses to your changes to the article talk page, so that you can follow them up if you wish. My feeling is that the content of the article is in good shape; all that is needed is to fix some of the stylistic and layout issues and it will have a much better chance. More at the article page. Mike Christie (talk) 23:09, 25 October 2008 (UTC)

Hi, Petergans. I agree with Mike that the article is well on the way; I've left some sample edits of issues that will help bring it over the hump. (Please review each of my edit summaries to understand the invidividual issues, including WP:ACCESS, WP:DASH, WP:MSH, how to write citations correctly, WP:MOSDATE#Precise language, etc.) Per your comment on my talk page: If this were a peer-reviewed journal, I would expect the editor to make a final decision regarding publication on the basis of whether the author(s) have responded adequately to the referees' comments. I assume that a similar process applies in WP. Unfortunately, unlike a peer-reviewed journal, we don't have paid staff members, and we must rely on volunteers who donate their time to review articles. When a nomination has been at FAC for two weeks, and hasn't gained consensus for promotion, it can become harder to entice reviewers to revisit, and a clean start once issues are addressed is often the fastest path to featured status. In this case, few reviewers had engaged, and the FAC commentary indicated a lot of work remaining; a clean start in a few weeks after all of these issues are dealt with is likely to yield the best outcome and attract more reviewers to Support. With Mike Christie on board, you should be in good shape: please renominate whenever Mike concurs it's ready (including the sample edits I left). SandyGeorgia (Talk) 21:53, 26 October 2008 (UTC)

Just checking in to see how it's going, and I realized you might not know why I suggested that you're in good hands if you work with Mike Christie: see WP:WBFAN. SandyGeorgia (Talk) 23:45, 29 October 2008 (UTC)

Osmotic coefficient

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Phase diagram

Hi...Thanks for adding a reference to the phase diagram article. I also see that you added a note saying that it covered most of the text in the article. If this is the case could you added page numbers for each paragraph, similar to the way the references are in the forging article, that way others can confirm it. Thanks! Wizard191 (talk) 14:19, 20 November 2008 (UTC)

I'm not clear what the real issue is here. Let me put it this way: all the diagrams in the article are famililiar to me from various physical chemistry text-books, going back to when I was an undergraduate, 50 years ago. In other words, this is "common knowledge". As it happens we've just been discussing the issue of common knowledge in chemistry at Talk:Acid dissociation constant in the process of getting that article promoted to featured article status. I suggest you also look at wp:SCR. For me, it's difficult to see the need to supply specific references to verify things that have been common knowledge for more than a century. [book review]. This book is still available! Petergans (talk) 19:27, 20 November 2008 (UTC)

I think you meant WP:SCG. I agree, and the forging article is an especially bad example, because all the citations are within 30 pages of the book or less (probably one chapter). We don't require pages to individual pages of journal articles, which may be longer than 30 pages. Why would anyone need citations to individual pages within a 30-page chapter? One citation to refer to the entire chapter or 30-page range should be enough. Or how lazy are our readers supposed to be? Even if one is referring to an entire 900-page textbook, (decent) textbooks have good tables of contents and indexes, which are useful even if one does not happen to have the same edition that was cited (textbooks are generally not cited for their brilliant quotations, but for facts which often don't vary from one edition to the next). --Itub (talk) 20:26, 20 November 2008 (UTC)

I apologize for the inconvenience. I was not aware of the policy WP:SCG. I generally edit metalworking and mechanical engineering articles where that policy does not apply.

FYI...I was asked to add the page numbers to reference each paragraph in the forging article. This is not unique. See welding which is a FA. Wizard191 (talk) 21:27, 20 November 2008 (UTC)