User talk:AndrewDressel/Archive 1

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Images

A note on images: the JPEG format, which you’ve been using a lot, is not very well suited for line graphics. In mathematical terms, JPEG encodes local gradients in matrices, which is a good method in some cases (e. g. for photographs) but fails in general. See also Wikipedia:Preparing images for upload for more information on this. I’ll try to convert some of your images to the SVG format (which encodes geometrical shapes and has a number of significant advantages over raster formats like JPEG), but two are problematic:

• For Image:BicycleEigenvalues.jpg, it would be easier to make the plot in SVG. If you made the plot in Matlab, try using this script to export to SVG.

- Hmmm. I can't get it to create an image that I can view. My browser doesn't need a plug-in to render SVG, does it? AndrewDressel 15:37, 30 July 2006 (UTC)

It depends. Most browsers do not have built-in support for SVG, the notable exceptions being Firefox, version 1.5 or newer, Opera, beginning with version 8, Safari, and, to some extent, recent versions of Amaya. If you are using Internet Exploder and can’t get Firefox, you can try Adobe’s SVG plugin. However, the best way to check whether an image will display well on Wikipedia is to use the same tool which is used here: librsvg, which includes a viewer for SVG files, rsvg-view, which shows almost exactly what an image will look like after upload. Recent Linux distributions should offer packages for librsvg and similar options are probably available for other popular Unix clones (e. g. MacOS X and the *BSDs), but I am unaware of a Windows port of the viewer (although the a port of the library itself is available). The second best way, imho, is to use Firefox. —xyzzy_n 16:08, 30 July 2006 (UTC)

…Neat! The dimensions were set a bit too low (the text is hard to read below 150% magnification), but since SVG is a vector format, zooming the image does not incur any loss of quality. —xyzzy_n 12:48, 31 July 2006 (UTC)

- Finally got it to work with Adobe’s SVG plugin. I think librsvg is a site that only a developer would love. So now the problem is that I don't appear to be able to scale the image. I created it to be the same size as the JPG image, on my machine at home. Now, here at the cafe, it is too small. Is that correct? Images in SVG format do not scale? That's not too handy. AndrewDressel 13:07, 31 July 2006 (UTC)

SVG images do scale, somewhat better than raster images. (For the former, all you have to do is an almost lossless coordinate transform; for the latter, you have to recompute the values of all pixels, and after that, there’s always a visible impact on quality.) I don’t know why the size is wrong. From skimming the script, I’d say that the output should have the size you set for the plot in Matlab. However, you could easily scale the image with Inkscape. —xyzzy_n 13:37, 31 July 2006 (UTC)

• For Image:BikeModel.jpg, I’m not really sure what to do. If you can get the image like that in Matlab, the same method as before might work. Otherwise, try exporting it to PNG (a lossless raster graphics format that is somewhat better than JPEG for this kind of image).

- It is written as VRML from MATLAB and rendered by a plug-in: Cosmo Player. AndrewDressel 13:07, 31 July 2006 (UTC)

In general, neither Word nor Paint are good tools for image creation or editing.

- They work fine for me. Since Wikipedia serves up raster images anyway, I don't really see the benefit of uploading vector images, especially if it means I then cannot scale them as necessary. AndrewDressel 13:07, 31 July 2006 (UTC)

The benefit of vector images is that you can scale them as necessary, without loss of quality. ;) Another benefit is that if somebody needs to edit a Wikipedia image, that can be done with relative ease if the image is in a vector format, but not so easily if it’s a raster image. —xyzzy_n 13:37, 31 July 2006 (UTC)

For vector graphics, try Inkscape. For other things, try GIMP. —xyzzy_n 14:00, 29 July 2006 (UTC)

Oops, I forgot about Image:BikeModel.jpg earlier. I can try to make a screenshot of the VRML file in PNG format if you send me the VRML file (e. g. compressed and by e-mail). I would then send the screenshot to you so you could upload it.

-Sure, you can follow the links on my page to find my e-mail address. I don't see yours on your page. Once you create the PGN image, you could certainly upload it yourself. There's probably some rule against uploading the VRML to Wikipedia, right? -AndrewDressel 03:22, 8 August 2006 (UTC)

There’s an ‘e-mail mail this user’ link in the ‘toolbox’ to the left (if you use the default skin). It’s not as comfortable as just putting the address somewhere, but I’m already getting enough spam. I think you can also just upload the VRML file—as long as the licence is right. That’s fine and we could link to it from the article, although VRML on Wikipedia is quite rare. The only example I have found so far is Image:Tetrakis_hexahedron.wrl. —xyzzy_n 14:19, 8 August 2006 (UTC)

Okay, I'll work on getting you a file. -AndrewDressel 14:31, 8 August 2006 (UTC)

(By the way, you have checked with your employer regarding uploading all those images to Wikipedia, haven’t you?) —xyzzy_n 00:41, 5 August 2006 (UTC)

-Ha ha. Which employer would that be? -AndrewDressel 03:26, 8 August 2006 (UTC)

Cornell University, I assume from your website. Did you create those images as part of your work for Cornell? —xyzzy_n 14:19, 8 August 2006 (UTC)

-Interesting question. I've been on a leave of absense for two years and have continued to work on my thesis. So, I'm not there and they are not paying me. In any case, I paid for my copy of MATLAB myself, the JBike6 application is freely downloadable, and its end user license agreement mentions only copies, not its output. -AndrewDressel 14:31, 8 August 2006 (UTC)

I guess it’s OK, then. (For future reference, see the last section of s:GPL for useful information.) —xyzzy_n 15:07, 8 August 2006 (UTC)

Bicycle and motorcycle dynamics

I’ve tried to change the citations a bit, away from the style of the articles you named in the todo list. The problem with it is that it’s difficult to follow while reading the article—it’s hard to tell whether a given citation refers to a newspaper article or a published paper. Also, with the other style, there is no need to maintain a second list of the same sources in the references section.

In the process, I omitted some sources because I did not think they are really usable. Since the article is about physics, it’s probably a good idea to stick to published scientific works for all important points. On this topic, could you please check whether Hand’s thesis has been published anywhere?

Regarding citation templates in general, please remember always to select the right one for a purpose (e. g. {{cite web}} for websites, but {{cite journal}} for (published) papers, even if there is an electronic version available) and read the documentation for the templates (on the template pages or their talk pages) to know the parameters.

As for the misconceptions, I don’t think the section should remain in that form at all. If there is a different point of view on the issue, it should be explained properly in the article—even if it’s technically wrong. —xyzzy_n 17:49, 4 August 2006 (UTC)

Hi, thanks for your message. This seems to be quite a complex subject, I’m afraid I’m not really qualified to add anything to the article. Compared to this, bottom brackets are a lot easier to understand! LDHan 22:58, 9 March 2007 (UTC)

Bicycle/motorcycle physics

You are one serious bicycle/motorcycle physics dweeb! I fell in love with the concept of countersteering when I first encountered it in the Motorcycle Safety Foundation course. Spalding 16:44, 29 June 2006 (UTC) (Copied from his talk page)

Countersteering (Duplicate of Talk:Countersteering)

That the lean angle is very small or that the handlebars are turned far in the direction of the desired turn does not mean that the momentary countersteering necessary to initiate that lean can be skipped. -AndrewDressel 14:52, 3 October 2006 (UTC)

I'm a farily experienced (motor)bike rider, and at very low speed, say walking pace, you do not countersteer (or at least it's optional), even to lean. Dave 04:23, 28 October 2006 (UTC)

How then do you create the necessary lean? -AndrewDressel 03:13, 29 October 2006 (UTC)

At the lowest speeds, you don't lean. Dave 17:01, 29 October 2006 (UTC)

Then how does one counter the Centrifugal force? -AndrewDressel 19:54, 29 October 2006 (UTC)

I don't see why it needs countering - tyre sidewalls should surely take it, as far as I know there's no reason why resultant force on the bike need be vertical (with respect to the bike). Dave

The reason the resultant force (sum of all forces) needs to be vertical with respect to the the bike (exactly coincident with the plane defined by the two wheel contact points and the combined center of mass of the bike and rider) is to keep the bike from falling over. I don't know what you mean by "tyre sidewalls should surely take it." -AndrewDressel 22:01, 29 October 2006 (UTC)

On reflection, as counter intuitive as it seems you must be right, as I can't see any other way there wouldn't be a resultant moment around the centre of mass. Dave 13:34, 30 October 2006 (UTC)

Reply to your inquiry regarding torque reaction in Talk:V-twin

I posted a reply to your inquiry. If you'd like to discuss, I'll check back there but I'm only on once or twice a week or so, so don't expect any heated discussions.  ;) Unfocused 03:28, 1 November 2006 (UTC)

Excellent, thanks. In fact, I pasted your entire 3rd paragraph into the article. I hope you don't mind. I actually have a Guzzi, and while I can notice when stopped at a light, it hasn't been a factor for me while riding. Perhaps I'm too casual. -AndrewDressel 19:54, 1 November 2006 (UTC)

Re: Gregarious Lonewolf's talk page

You wrote in the edit summary: (Fix typo: Those -> Though (hope you don't mind))

Thank you! No, I didn't mind it at all. :) Gregarious Lonewolf 20:08, 3 November 2006 (UTC)

Re: "a thread pitch unique to bike pedals."

Andrew: My error, unintended, was perhaps one of wording clarity, not technical accuracy. It is the "size & thread pitch" combination which is unique to bike pedals, see http://www.sizes.com/tools/thread_american.htm , as one of many examples, inc;luding your one Sears marketed tap & die set.

The SAE standard fine thread pitch for bolt size 9/16" is 18 TPI, not 20 TPI. No major bolt/nut, tap/die, or thread repair device manufacturer (including any custom product manufacturer I could find) in the U.S. or abroad, offers any products in a 9/16" x 20 TPI combination, even in only a RH tread. After a rather extensive Google search (broadband connection), Park (previously unknown to me) was the only manufacturer I could find which offered any 9/16" x 20 TPI taps, RH & LH threads (which I ordered from the lowest cost net retailer I could find); they do not offer dies in this size.

TPI is an individual characteristic; the reason TPI gauges are routinely supplied in better quality tap and die sets. As with all fastening systems, it is combinations of characteristics which come to be recognized as standards, not individual characteristics. My comment about the "9/16 in. x 20 TPI" combination being quite unique to bicycle pedals is factually correct, an apparent historical but accepted event in the history of bicycle part manufacturers, assemblers and retailers. "9/16 in. x 20 TPI" is neither a United States (SAE: Society of Automotive Engineers, sae.org usually the dominant authority) or a metric standard. Given current practice to manufacture bicycle cranks from aluminum, the 20 TPI standard, as opposed to the national course "9/16 in. x 12 TPI" standard, which provides a much deeper thread, renders bicycle pedal bolts more prone to stripping out the finer/shallower 20 TPI treads within bicycle cranks. It is also the reason many local bicycle shops either carry specialized repair kits for bicycle cranks (generally rated as of poor reliability by many in the bicycle business) and/or sell crank replacements.

The above issues are part of the reason I ended up doing a search on the "9/16 in. x 20 TPI" engineering odyssey. Having extensive mechanical engineering experience and some small scale manufacturing capability, I elected to purchase the Park taps and will manufacture my own steel inserts from center-drilled grade 8 bolts and in-turn drill, tap and epoxy these custome inserts into cranks needing repair. This should end up more reliable than most currently available cranks, in terms of pedal thread toughness.

As such, and for the benefit of others, I would suggest that you correct, rather than delete the comment about "9/16 in. x 20 TPI" being unique to bicycle pedals. Thank you. MA | T@lk 14:56, 26 November 2006 (UTC)

I believe that you will find that 20 TPI is an old BS Cycle Thread Coarse measurement. I'm well experience in "odd" threads as a Norton and Soviet bike owner. I believe that Bicycle Tap and Die sets are still manufactured in Russia and other parts of the FSU and you should be able to find those dies. M-72 07:38, 19 December 2006 (UTC)

bicycle and bicycle gearing

You've done a great job on moving stuff between these articles. Murray Langton 08:59, 30 November 2006 (UTC)

Motorcycle Forks

You are welcome for the photographs! I am glad you find them useful. -Jeff dean 23:21, 9 December 2006 (UTC)

I don't know who the mysterious M-72 is, but I appreciated and learned form his additions to your motorcycle forks page. He should make himself known! -Jeff dean 15:10, 10 December 2006 (UTC)

I know what you mean. Isn't it fascinating what information comes out of the woodwork? -AndrewDressel 15:53, 10 December 2006 (UTC)

Coaxial steering front suspension

But ... what does it LOOK like?? :) -Jeff dean 18:20, 15 December 2006 (UTC)

Hard to tell exactly. Plus, any image I can find certainly is copyrighted. Anyway, you can find some pictures here [1] that do not reveal much. Good luck. -AndrewDressel 21:04, 15 December 2006 (UTC)