User talk:Srleffler

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Antireflective coating

(→‎Index-matching: "Normalized" is unclear here.)

The form is r=(n1-n2)/(n1+n2), squared for intensity. It is not proportional to n1-n2, but is close for small (n1-n2). I am not against your change, though. Gah4 (talk) 06:42, 9 January 2016 (UTC)

I know. Calling that "normalized" without further explanation isn't clear enough to the reader. Better to point them to Fresnel equations and leave it at that.--Srleffler (talk) 07:18, 9 January 2016 (UTC)

Talk:Dispersion

Hi, I removed the comment because it was one of several random utterings from that user going back weeks. See their deleted contributions for the worst examples. --Redrose64 (talk) 10:52, 9 January 2016 (UTC)

I understand. I assumed good faith on this particular edit.--Srleffler (talk) 14:00, 9 January 2016 (UTC)

Info deleted from Incandescent light bulb

In 2016, researchers have developed a way to improve the efficiency of the incandescent light. Incandescents right now only convert only 2-3% of their energy into light. The scientists created an incandescent bulb that converts 6.6% of the energy into light. They theoretically can convert 40% of the energy into light which is three time more efficient than LEDs. They have built a structure that surrounds the filament of the bulb and captures the leaking infrared radiation, reflecting it back to the filament where it is re-absorbed and then re-emitted as visible light.<ref>New development could lead to more effective lightbulbs, BBC News, 12 January 2026, Matt McGrath</ref>

This paragraph below is missing important info from the paragraph above.

Prompted by legislation in various countries mandating increased bulb efficiency, new "hybrid" incandescent bulbs have been introduced by Philips. The "Halogena Energy Saver" incandescents can produce about 23 lm/W; about 30 percent more efficient than traditional incandescents, by using a reflective capsule to reflect formerly wasted infrared radiation back to the filament from which it can be re-emitted as visible light.<ref>Broydo Vestel, Leora (6 July 2009). "Incandescent Bulbs Return to the Cutting Edge". The New York Times. Retrieved 6 July 2009.</ref> More advanced reflectors can theoretically be much more efficient. Laboratory proof-of-concept experiments have produced as much as 45 lm/W, approaching the efficacy of compact fluorescent bulbs.<ref>New development could lead to more effective lightbulbs, BBC News, 12 January 2026, Matt McGrath</ref><ref>Ilic, Ognjen (2016). "Tailoring high-temperature radiation and the resurrection of the incandescent source". Nature Nanotechnology. doi:10.1038/nnano.2015.309.</ref>

Would you consider adding some of the info from the first paragraph?

--Wyn.junior (talk) 23:31, 13 January 2016 (UTC)

The original paragraph put too much weight on this research result. It's a laboratory proof-of-concept experiment, not a developed commercial product. The 40% number is completely theoretical; it's not clear that even the researchers think they can approach that in practice. I think my version captures all of the useful information and puts it into proper context and with proper weight. What do you think is missing?--Srleffler (talk) 06:59, 14 January 2016 (UTC)

is a Keplerian telescope afocal?

Perhaps the author was thinking about a Keplerian telescope, but I do not think such a telescope matches the description given, while I think a Gallilean telescope does. While Kepler's design makes a generally better instrument, I think simple, "opera glass" telescopes are still quite common. --AJim (talk) 04:07, 25 February 2016 (UTC)

Answering my own question, yes, it is, under the specific conditions they specify. In fact they go on to show how the sign of the magnification tells whether the image is upright or inverted. I still think it could be helpful to a learner to make the connection from this theory to the two historical telescope names. --AJim (talk) 01:11, 26 February 2016 (UTC)

I agree. I added a link to the end of the section that points directly to Refracting telescope § Refracting telescope designs, so that readers who are interested in learning more about telescopes can. I think this is better than having an easter egg link to optical telescope. --Srleffler (talk) 02:11, 26 February 2016 (UTC)

Could I now put on Wikipedia.en references to my simulation program?

In April 2014, I made an attempt to put on Wikipedia.en my simulations, which are meant to help lecturing students in classical physics. You refused them, (see item 6 of the Contents list of your talk page) because you felt these simulations were not safe, coming from a personal google site. You wanted me to use a "certified" site, the one of an university for instance. Since that time, among others things, I moved my programs to the site of my former lab (I am now retired): the "Laboratoire de l'Accélérateur Linéaire" (LAL) at Orsay, which is one of the mean French lab in High Energy physics. So there should be no more safety problems. You told me also that the way my programs were proposed, as executable .jar's (java exec's), which are to be downloaded, were not very appropriate. So I stick to these .jars, which seem to me the most handy way to work. I ask you if it were any way possible to put my simulations on the english version of wikipedia. These simulations can be seen using the link: https://groups.lal.in2p3.fr/simulations-pour-cours-de-physique, with french items, all of them translated into English as well (the wikipedia.en visitors would go directly to english versions).

Best regards. Truocled (talk) 17:24, 4 March 2016 (UTC)Truocled

I won't stand in the way.--Srleffler (talk) 02:27, 6 March 2016 (UTC)

I apologize, but your answer is not clear to me (my understanding of English is still not perfect). Does it mean that you are not opposed to see my programms on Wikipedia.en, or that you are opposed to it? Truocled (talk) 14:33, 6 March 2016 (UTC)

It means that I won't prevent you from adding the links. (Not standing in someone's way means not blocking their path, stopping them from going where they want to go.)--Srleffler (talk) 20:16, 6 March 2016 (UTC)

I have put four external links on the pages; of Michelson and Fabry-Pérot interferometers, of Young slits and of microscope. Best regards . Truocled (talk) 17:54, 2 July 2016 (UTC)Truocled

Spectral Irradiance edit undo

It was that very difference I was trying to make clear, as if you didn't read my reason for the edit... maybe some extra commas would more properly relate correctly the clauses... ok went back to look at it again and now it is much clearer as to what is referring which. Better than what I did. DPHutchins (talk) 06:26, 7 March 2016 (UTC)

Your edit summary seemed to indicate that you didn't understand that the two types of spectral irradiance have different dimensions. Your edit was nonsense: "watt per square metre per the wavelength of a particular frequency in hertz" doesn't mean anything, and "W·m⁻²·λ⁻¹" is just flat out wrong. "λ" is not a unit symbol.--Srleffler (talk) 06:58, 7 March 2016 (UTC)

Luneburg lens edit undo

Hi, could you please comment on your motivation about removing external link, because it is in a different language?

I agree that links to English language pages are more appropriate *if they exist*, but I've found only very short summaries in English, unlike the rather detailed instructions and description of the antenna "construction" and testing in my link. rado (talk) 08:42, 31 March 2016 (UTC)

The guidelines on this are at WP:NONENGEL. The English language Wikipedia is for people who read English. External resources in other languages are of no use to our readers, in general. Your link belongs in the Portugese Wikipedia.--Srleffler (talk) 00:50, 1 April 2016 (UTC)

Thin-film interference

Thanks for your assistance. That does look a lot better and more concise than what I had for the lede. I knew I should've just let you take care of it.

Part of my trepidation, however, comes from defining a term with that term. In example from our own article (which I plan to clarify soon): "A solid solution is a solid-state solution of one or more solutes in a solvent." (Huh?) Of course, I know what it's saying, but to the layman it's pure gibberish. Or until recently we had "Air combat manoeuvering (ACM) is the art of manoeuvring a combat aircraft." (Well, duh?) I know we have wikilinks to articles that (hopefully) define the terminology, but for the opening sentence I have usually found it helpful to clearly define the jargon for the layperson, so they don't have to click three different links to get the gist of it. Do you think there is a simple way to define both "thin film" and "interference" in the opening sentence, so that the definition doesn't seem so circular? Zaereth (talk) 00:16, 6 April 2016 (UTC)

I think it's fine as it is. It's not defining a term with the same term; it's breaking a term down into simpler concepts: thin-film interference is interference in a thin film. The linked articles are fine for the reader needing a thorough explanation, and the rest of the lede gives a good-enough overview for a reader who doesn't need so much detail. --Srleffler (talk) 03:39, 6 April 2016 (UTC)

Ok, sounds good. My first instinct was to simply look for some synonyms, but there really aren't any, so I thought I'd ask to see if you had any ideas. I guess in this case it's best to leave them as self-explanatory from context. Thanks again for your help. Zaereth (talk) 21:11, 6 April 2016 (UTC)

Reference

I've added a couple of ref at Numerophobia. Please check.--Vin09 (talk) 05:59, 9 April 2016 (UTC)

I've deprodded the article. The reason is given in the old prod box on the talk page. Thanks! Uanfala (talk) 10:51, 9 April 2016 (UTC)

Corrigendas

It appears Corrigendas Special:Contributions/Corrigendas has been changing refs links to http://www.tunablelasers.com on several pages that I checked. Including List of laser applications What's your view on this? Cheers Jim1138 (talk) 07:10, 12 May 2016 (UTC)

It's clear promotion of his own website. Corrigendas is clearly F.J. Duarte, from his past editing history. I don't have any doubt in his academic credentials or the merits of his work, but he has a long history of trying to promote it on Wikipedia --Srleffler (talk) 05:09, 13 May 2016 (UTC)

(also @Jim1138:) You both may be interested in this discussion which didn't get picked up at the time. I simply did not know what to do about it, nor do I know now. I was wondering something, maybe you guys can answer---just how notable is Duarte's work in that field? It's hard to judge as an outsider. --Nanite (talk) 07:26, 13 May 2016 (UTC)

@Nanite: Time for an ANI? Jim1138 (talk) 17:06, 13 May 2016 (UTC)

@Nanite: I don't doubt that Duarte is notable, but he seems to have been promoting his work, his websites, and his books on Wikipedia for a long time. There is clearly undue coverage of his work here, and many external promotional links that should be removed. He has a lot to contribute on his topics of interest, but seems not to be able to avoid conflict of interest.--Srleffler (talk) 03:18, 14 May 2016 (UTC)

I did a quick survey of articles that link to his article. Not all of what I found was objectionable; perhaps most would not be if it were posted by someone other than Duarte himself. I don't doubt that he is notable, and not all discussion of and references to him and his work are undue. The worst things I found were references to articles on the "Optics Journal" website, which appears to be a fake journal owned by Duarte himself. While its perfectly legitimate for him to self-publish essays and editorials that way, there is absolutely no way under WP:RS that those works should ever be cited on Wikipedia. Particularly egregious was self-published criticism of Kodak and several of its executives, which was discussed and referenced in several Wikipedia articles. I removed references to "Optics Journal" wherever I found them, but probably missed lots.--Srleffler (talk) 04:46, 14 May 2016 (UTC)

Yes, I noticed this myself from the dye laser article. Duarte is definitely notable, especially in the field of lasers and dye lasers in particular. However, there were some truly bizarre edits from multiple accounts (Corrigendas, Northryde, Singlephoton, CSCarlton, to name a few) as well as a slew of similar IP addresses. Weird edits, such as linking his name in every reference where it appeared. That provoked me to put Duarte's article on my watchlist. Lot's of edits to references. Many edits, however, were perfectly good and even helpful, so I wasn't sure what to make of it, but have been watching closely. I usually don't revert unless it's like blatant vandalism or something, so I was kinda waiting to see what others would make of it. Zaereth (talk) 07:24, 14 May 2016 (UTC)

Question about image

Hi Srleffler,

I had a question about a diagram. I'm not too familiar with copyright laws, especially with images, so I usually upload only my own, and typically only when I se a need for one. I was fooling around one day with this image of a fluorescent lamp in a diffraction grating, and decided to cut a strip from the center and paste it to the graph. Lo and behold, all the peaks matched up almost perfectly. I thought it looked really good, adding some color to the graph. I tried to contact the author of the graph, but they seem to have disappeared.

Do you think it would be ok to upload the modified image as a derivative work, attributing it to the author of the graph? I think it would add both some aesthetic value, plus help the reader visualize where the visible peaks are on the chart. A problem is that I am not able to do anything with SVG files, so I'd have to upload as a JPEG. Do you think it would even be worth it? Zaereth (talk) 22:02, 23 May 2016 (UTC)

Yes, it's fine. You can read the license yourself at the commons page. You're free to modify the image and reissue it under the same license as long as you list the other contributors. See the "author" box on that page for an example. The ability to modify contributions to the project is a key part of Wikipedia's structure. Go for it.--Srleffler (talk) 06:10, 24 May 2016 (UTC)

Dioptre

I see you reverted my recent edit here. You are welcome to claim that a 0-dioptre lens does not technically converge rays of light at infinity (though this is what is "mathematically" suggested when you divide 1 (the length of a meter) by zero (the dioptre of a zero-dioptre "lens")). That is semantics, and I won't argue it. That there is no such thing as a zero-dioptre "lens" is untrue, however, and I wish you would reconsider that part of your reversion: how do you describe the dioptre of a flat piece of glass? Does a piece of glass exist as a lens at a dioptre of +0.00001 but then cease to be one when it reaches +0.0? If so, that is also semantics and the lay reader will not grasp it. Stating that a flat sheet of glass has a dioptre of +0.0 is a very useful concept for the non-expert who is struggling with the concept of correction. Wikipedia is intended to be for non-experts. Saying that a 0-diopter lens is a flat piece of glass is not untrue— it is just not the usual way of describing such a thing, and that makes it a very useful thing for understanding the concept of dioptre! I invite you to reintroduce this idea into the article somehow, if you would. If you didn't like my phrasing, then I would very much like to see your own, yes? Thanks! KDS4444 (talk) 10:32, 5 June 2016 (UTC)

I added something to the article. See what you think.

A refractive element with no optical power is a window, not a lens. Whether an element with a power of 0.00001 D is a very weak lens or an imperfect window probably depends on its intended application. It's semantics, but semantics matters even when talking to non-experts. Talking about a nonsensical optical element that doesn't exist is not going to help a naive reader to understand better. A naive reader is not going to understand what a "0-dioptre lens" is, but they do know what a window is, so it's better to explain that windows have no optical power (0 D) than to talk about a nonsense 0-dioptre lens.--Srleffler (talk) 00:21, 6 June 2016 (UTC)

ArbCom Elections 2016: Voting now open!

Hello, Srleffler. Voting in the 2016 Arbitration Committee elections is open from Monday, 00:00, 21 November through Sunday, 23:59, 4 December to all unblocked users who have registered an account before Wednesday, 00:00, 28 October 2016 and have made at least 150 mainspace edits before Sunday, 00:00, 1 November 2016.

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Lightbulbs listed at Redirects for discussion

An editor has asked for a discussion to address the redirect Lightbulbs. Since you had some involvement with the Lightbulbs redirect, you might want to participate in the redirect discussion if you have not already done so. Thryduulf (talk) 19:43, 19 December 2016 (UTC)

RE: Cardinal point (optics)

Hello, I do understand that you have to rotate the entire optical system and that the projection onto the non-spherical focal plane has an effect. I still am not convinced either way at the moment, and all references I have read are not complete in their analyses. In my actual work I don't do a lot of geometric optics, so I don't have great intuition on this particular subject. A full analyses of this particular issue would be a nice photography or physics stackexchange Q&A. Cheers, Daaxix (talk) 01:42, 30 December 2016 (UTC)

Van Eck Radiation

Years ago, I asked you about this, I found out what it is, it was the phonetics of the word that threw me off. I thought it was spelled "Vanic Radiation" here it is, unless you're interested, https://en.wikipedia.org/wiki/Tempest_(codename) it's not very direct/specific about, it glosses over/mentions it, you might also want to check this out: https://en.wikipedia.org/wiki/Van_Eck_phreaking, in a nutshell it's a form of radiation given off by EM devices that can be picked up and used to eavesdrop on people. I think it needs it's own article, though The snare (talk) 06:22, 6 February 2017 (UTC)

Wow, ten years ago, actually. Glad you finally found an answer.

The radiation should not have an article of it's own, because it isn't really a distinct thing. It's the fact that these leakage radiations can be used to eavesdrop that is notable; Van Eck phreaking is the correct placement for this on Wikipedia. Van Eck radiation now redirects to there.--Srleffler (talk) 03:41, 7 February 2017 (UTC)

I found the answer much sooner than just recently, but thought you might have wanted to know The snare (talk) 13:29, 15 February 2017 (UTC)

if you ever have the time I asked some things on my user page. Also, I wanted to ask, how is it possible that there is an equal number of protons to electrons in the universe, wouldn't it change every time an electron annihilates with a positron? The snare (talk) 20:22, 20 December 2017 (UTC)

Why do you think there are an equal number of protons and electrons in the universe? I have no reason to think that is true. Note, though, that charge is conserved, which means that if the Universe started with no net charge, it should have equal amounts of positive and negative charge today.--Srleffler (talk) 03:02, 21 December 2017 (UTC)

Take a look at this, specifically time index 7:50-8:00, is he wrong? https://www.youtube.com/watch?v=twq8h9BXY0I The snare (talk) 03:36, 21 December 2017 (UTC)

Plasma globe

Plasma globe

voltage is potential charge,

Voltages does condense in a condenser, IE capacitor. Read something by Tesla and he uses this language all the time.

electron volts corresponds to electron velocity (EV), hence Bremsstrahlung, de-acceleration radiation increases with voltage, not amp flow.

Gibberish? you know very little then...you must know nothing about electromagnetic induction

High voltage is not compatible with low voltage, you need Education on the subject; if you think a LC circuit or electromagnetic induction is gibberish.

"Earth Ground Should be used as lowest source of (-e) electron."

IS VERY CLEAR, electrons should be coming from the earth ground, not air ground, again, get Educated.

what grammatical errors are there? or are you wasting my time? — Preceding unsigned comment added by 75.86.98.216 (talk) 18:21, 20 March 2017 (UTC)

voltage is potential charge,

Voltages does condense in a condenser, IE capacitor. Read something by Nikola Tesla and he uses this language all the time, for instance, my reference Tesla, Nikola (1892). "Experiments with Alternate Currents of High Potential and High Frequency" Uses this definition over 40+ times! do you read before posting/editing?

electron volts corresponds to electron velocity (EV), hence Bremsstrahlung, de-acceleration radiation increases with voltage, not amp flow.

Gibberish? you know very little then...you must know nothing about electromagnetic induction

High voltage is not compatible with low voltage, you need Education on the subject; if you think a LC circuit or electromagnetic induction is gibberish.

"Earth Ground Should be used as lowest source of (-e) electron."

IS VERY CLEAR, electrons should be coming from the earth ground, not air ground, again, get Educated.

what grammatical errors are there? or are you wasting my time?

The entire book has reference to high-voltage-high frequency application, from gas-discharge tubes to inductive coils...

"causing real current to flow" LOL! now that's some gibberish, and un-referenced, BTW. Whats that supposed to mean?? are you confusing high voltage with low voltage?

One example of grammatical errors is the statement that "glass becomes heat." Glass cannot change into heat anymore than iron can become speed. The statement is nonsensical. Voltage is potential in an electrical system the same way pressure is potential in a hydraulic system. The potential does not correspond to speed. In an electrical system (just as in a hydraulic system), the potential is highest when no current is flowing, and drops as current increases. (ie: When you open the valve on a water faucet there is a sudden drop in line pressure.) An electron volt is a measure of work, in specific, the work done on one electron when it accelerates (or decelerates) through a field with a potential of one volt. With the exception of lightning, electrons rarely come from Earth ground, except to replenish what is lost in a circuit from leakage. In most electrical systems, the electrons are contained in the metals of the generator coils, and are simply "pumped" in a circle by the generator. High and low voltages are certainly compatible. One example is the series-triggered flashtube, where a high-voltage signal is injected directly into the lower-voltage of the flash circuit. I'd keep in mind that Tesla was at the forefront of electrical investigations, and lacked much of the knowledge that we have today about what electricity is and how it works. Zaereth (talk) 20:01, 20 March 2017 (UTC)

You're wrong, or do you purposely mis-quote people? I've never once stated "glass becomes heat." i said -If the glass heats and temperature is a concern, use -air cooling-. LOL! and that's not grammatical BTW... pumped? you mean electromagnetic induction! all electrical systems based off the "grid" use earth ground, flip a switch in your house, and you are making a fused earth ground contact. you've proven your ignorance on this subject to me more then enough... Get Educated, you clearly are not. As pressure increases and resistance stays constant, velocity increases as well! especially if you are using the "water" reference which is not a electron btw. "if electricity behaves as an in-compress-able liquid" as Tesla said, right?

"I'd keep in mind that Tesla was at the forefront of electrical investigations, and lacked much of the knowledge that we have today about what electricity is and how it works."

what a foolish statement, isn't Maxwell, Steinmetz, and JJ.Thomson, Tesla, etc, many others from the 1800's still used today? or are they "old"? i think you know nothing about the subject and make efforts to suppress information, but that's just my opinion.

Sorry, but that is completely wrong. Check any bacsic electrician's handbook. (I can recommend several.) When a switch is flipped in a house, the connection is from hot to neutral (for 110/120v), or hot to hot (for (208/240/277), or even hot-hot-hot (480V). A ground wire is provided only for fault protection, to prevent shocks from traveling through the body. Most appliances below a certain wattage don't even have ground wires, and before the 1960s they weren't even required. (My house, built in the 1940s is not even grounded at all.) For electricity to work it must travel in a full circle. Zaereth (talk) 23:43, 20 March 2017 (UTC)

you're wrong again, the "neutral" you reference is a fused ground. check with a ohm meter you will see they are connected, houses have always had a fused ground called neutral...the ground is UN-fused, the only difference. you are very wrong. lol electrician's hand book, you must not of read yours... — Preceding unsigned comment added by 75.86.98.216 (talk) 23:55, 20 March 2017 (UTC)

In the case of the neutral, the ground is merely a conductor back to the generator, which itself is grounded. A simple example is an electric fence. A fence that is electrified will not shock you unless the negative terminal is planted in the ground, providing a pathway from the fence, through your body, the ground, and back to the source. For 208V and higher, there is no neutral. In this case, the circuit runs totally through the wiring. Zaereth (talk) 00:16, 21 March 2017 (UTC)

You just said it, the neutral→ goes back to ground... the 240v line you refer to, are two 120v lines divided by a grounded center tap.

here are some images you might be able to understand...

http://www.rain.org/~mkummel/stumpers/10jan03b.gif http://www.rain.org/~mkummel/stumpers/10jan03c.gif http://www.rain.org/~mkummel/stumpers/10jan03d.gif http://central-energy.com/images/Single%20Phase.gif

— Preceding unsigned comment added by 75.86.98.216 (talk) 00:28, 21 March 2017 (UTC) 

Please, prove that you're wrong some more, i welcome it ;)

Zaereth's complaint about you writing "glass becomes heat" is a reference to this edit, where you did in fact write that. It's clear what you meant, and you wrote it correctly several other times. In that case, though, you were in a hurry to replicate the edit that had been reverted, and as a result you wrote carelessly and got it wrong. It's a petty issue in itself, but I think it is an example of a broader issue. In many cases where you've written ungrammatical or incoherent sentences, there is a clearer version in one of your earlier edits. If you slowed down a bit, and tried to improve what you've written instead of carelessly dashing off a less-coherent version of what you wrote before and slamming it back into the article, you might have been able to get your text accepted.

Poor grammar isn't necessarily a barrier to adding material to Wikipedia. If other editors can figure out what you meant, they will usually just correct the grammar and move on. The problem comes when the grammar prevents other editors from figuring out what you meant. In that case, they will much more likely remove the material. If you delete text and replace it with ungrammatical text that other editors can't interpret, it becomes almost certain that they will simply revert to the previous text. The solution is not to just reinsert the same flawed text again, and certainly not to insert a less-coherent version of it.

I'll leave the discussion of grounding to you two and other technical issues to the article talk page. I did want to respond to the comment about whether "Maxwell, Steinmetz, and JJ.Thomson, Tesla, etc, many others from the 1800's [are] still used today". While these great scientists are still revered for their contributions to our modern understanding of electricity, their writings are in fact not used much today, being somewhat antiquated. Science moves on. Old formulations are replaced by better ones. Concepts and theories get refined over time. Maxwell is a particularly good example. Every engineer and physicist learns Maxwell's equations. They are the core of modern electromagnetic theory. The equations we all learn are not the ones Maxwell published. See History of Maxwell's equations for a discussion of how the modern equations were developed based on Maxwell's earlier work. --Srleffler (talk) 04:43, 21 March 2017 (UTC)

@Srleffler Rv. Naadal again. Linkspam; poorly written site attempting to promote itself on Wikipedia.

@Srleffler

Ok. let the article given in Naadal might be poor. Can you please give a proper definition about spot diagram and spot diagram for spherical aberration. Because i am very much curious to know about spot diagram of spherical aberration.

Williambeke - Laser cutter image

Hi Srleffler

"Thanks for your edit to Fiber laser, but we can't use that image as things stand. The image appears to have been taken from the HACO website, which is copyrighted. Wikipedia can't use copyrighted images unless they are appropriately licensed. When you uploaded the file you selected "Own work" as the source of the image. Did you actually take this picture yourself? Uploading the image to Wikipedia requires you and HACO to release the image under an open license, which allows anyone to use it for any purpose.--Srleffler (talk) 23:43, 22 June 2017 (UTC)" --> I work at HACO and took this picture myself. Please accept the change of this image, we hereby release all our images under open license :)

Thanks! — Preceding unsigned comment added by Williambeke (talk • contribs) 05:44, 23 June 2017 (UTC)

Flobbadob re. Silphium

Hello Srleffler

Glad you liked the Heracleum image, even if you felt it wasn't an appropriate addition.

Re. 'indehiscent mericarp' (thank you for leaving it in, with the link, despite your reservations) - no, I don't think it's overly technical, given that a) 'Silphium' is a page about a plant and therefore botanically orientated and b) not only is Silphium known to have been an Umbellifer, but known also, with reasonable certainty, to have been a species of Ferula - or at least of some closely-related genus in the Apiaceae.

If you are going to devote a page to an Apiaceous plant, I think it's highly relevant to provide information about what constitutes an Apiaceous fruit. Surely it is one of the functions of Wikipedia to educate - how technical is 'overly technical' ? As, primarily, a physicist, do you think botany is of only secondary importance and that therefore a bit of botanical exactitude doesn't matter? I am glad to see that you've refrained from reinstating any references to the Silphium fruit being a 'pod', which it could not possibly have been if Silphium was, as seems pretty certain, an Umbellifer (Apiaceae).

Forgive me for getting a little worked up - it's just that I feel one of the most admirable features of Wikipedia is the way in which we can weave an interconnected web of knowledge that creates surprising and delightful links between what have hitherto been specialisms or disciplines partitioned off in their own little 'boxes' and oblivious to each others' areas of study. I enjoyed your Silphium page a great deal - I would not have felt moved to add to it otherwise.

Incidentally, the reason that I chose an illustration of a Heracleum mericarp, not a Ferula mericarp was that I couldn't find a free image on Wikimedia Commons of a close-up of a Ferula mericarp - heart-shaped or otherwise. I often visit botanic gardens in order to take photos to upload to Wikimedia, so I'll keep an eye peeled for you to find a heart-shaped Ferula fruit.

cordially yours (pun intended...)

Flobbadob.

Good points. I put the image back, with different layout.

No, I don't think of botany as being of secondary importance. Frankly, I wasn't really thinking of this as a botany article (although of course it is). I'm more interested in the history, and thought of it more as a history article.--Srleffler (talk) 02:31, 2 August 2017 (UTC)

Incandescent, reflective, halogen

Hi, my tagging of the text merely goes on the claim that Phillips is using an IR-reflective coating in their halogen bulb. If we both agree that this is not what the source says, this segment of text should be reworded to avoid confusion. Artoria2e5 contrib 05:27, 8 September 2017 (UTC)

The source says pretty clearly that the Phillips bulbs are using such a coating.--Srleffler (talk) 05:59, 8 September 2017 (UTC)

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Battlefield illumination

Hi, I've reviewed this article. The topic is obviously notable and it's great that you've filled a gap. I've added an image and a couple of citations; much remains to be done. However, you are experienced enough to know that you should have provided some halfway decent citations for this stub; the one ref that there was, was to the Art of War, a historic source, and that without a page reference. All the best, Chiswick Chap (talk) 10:06, 5 December 2017 (UTC)

Thanks. I didn't write that stub; I just copied it there from an older version of Lighting. That section had been deleted, but Battlefield illumination still redirected to it.--Srleffler (talk) 04:14, 6 December 2017 (UTC)

Thank you

...for the enormous improvements you have made to Lasers in cancer treatment. You could probably tell that I am not an expert on the topic but was dismayed that such an important topic wasn't covered on WP. You made the article so much better and I apologize for all the inaccuracies that I unintentionally had in the article. You are free to check up on other similar topics that I have worked on or created. Thank you very much and Best Regards, Barbara (WVS) ✐  ✉ ^{and Merry Christmas} 13:29, 21 December 2017 (UTC)

Merry Christmas

And a Happy New Year. Thanks, Srleffler, for all you do around Wikipedia. I hope your holiday season is a joyous one and the coming year brings many days of happiness and wonder. _{(By the way, if you don't celebrate Christmas then please take it as a Happy Hanukkah, Merry Makar Sankranti, Enlightening Bodhi Day, Merry Yule, Happy Tenno no tanjobi, or fill in whatever holiday is your preference.)} Zaereth (talk) 00:39, 23 December 2017 (UTC)

Merry Christmas to you too!--Srleffler (talk) 05:02, 23 December 2017 (UTC)

M squared

Hi, I absolutely agree with your interpretation of focus size vs M2. Why don't you put this explanation in the article? The way it is presented now is misleading: it is not clear that the comparison is between the multimode beam and the embedded Gaussian, rather than the Gaussian of the same size. Actually, most people working on laser applications are looking for a simple answer to the question: "I have a beam of a given size and a given M2. What is the minimum size I can focus it to with a given lens?". And the answer they get in the "Applications"(!) section of the article is "M times larger than a Gaussian at same wavelength". So they calculate the size of the focus of a same-size Gaussian and multiply it by M. — Preceding unsigned comment added by Mpolyanskiy (talk • contribs) 23:10, 11 January 2018 (UTC)

Good idea. Done.--Srleffler (talk) 16:30, 13 January 2018 (UTC)