Wikipedia:Reference desk/Archives/Science/2016 June 16

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June 16

FTIR

I've just seen a used FTIR machine on eBay for only $300, and it appears to be in good shape, but it has failed 2 of the self-tests -- the non-volatile RAM read and the +12V high-current test. My question is, will this machine be functional despite failing these self-tests? In other words, is it a bargain, or a waste of money? 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 05:14, 16 June 2016 (UTC)

Well, the NV RAM means it won't remember settings when you switch it off, and may have to be recalibrated every time. The 12V problem is probably something to do with the IR side. If it's a good make buy it and strip it for spares. I see they have a working Nicolet for $750, if that is what you want Greglocock (talk) 08:58, 16 June 2016 (UTC)

Spares for what? I don't have an FTIR unit right now -- I'm just getting set up, and I need a not-too-expensive FTIR machine (I'm on a pretty tight budget right now) so that I could do my own quality control rather than having to send every specimen of my product to an outside lab for analysis (which costs money too). So whichever machine I buy will be my only one for the time being (at least until I get the crowd-funding done and start getting ready for full-scale production), and will be used for its primary purpose. So with all this in mind, do you think it will be better for me to buy the good machine for $750, the not-so-good one for $300, or just forget the whole thing and outsource the FTIR analysis to an outside lab? 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 09:33, 16 June 2016 (UTC)

It might work fine, or it might be worthless. If I already owned such a machine, I would try to run it against known standards and see how it performed. It might work okay. However, without more testing I doubt one could tell. Buying such a machine based solely on your description would be a gamble. If the seller has multiple machines, you could try asking them to show an analysis using the somewhat faulty machine and a fully functional machine and verify that they are similar. Personally though, I wouldn't buy any mission critical equipment with known faulty hardware. It's generally not worth the headaches and worry. Dragons flight (talk) 10:20, 16 June 2016 (UTC)

What about repairing the machine -- would it be worthwhile, or would it cost less to buy the fully functional machine? (Once again, the faulty machine costs $300 and the fully functional one costs $750.) 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 10:34, 16 June 2016 (UTC)

Note the Refdesk is for answering questions, not giving advice. There's no money back guarantee here if you are steered wrong. It would be more productive to ask and answer where manuals about these tests or other specifications might be found. Wnt (talk) 12:17, 16 June 2016 (UTC)

OK, let me put it another way: If I decide to buy the faulty FTIR machine and have it repaired, how much can I expect the repairs to cost me? 67.164.54.236 (talk) 01:28, 17 June 2016 (UTC)

There's an FTIR power supply on ebay for $410. Various suppliers have IR sources for also in the $400 vicinity. DMacks (talk) 03:28, 17 June 2016 (UTC)

Thanks! 67.164.54.236 (talk) 05:10, 17 June 2016 (UTC)

I think the big issue is what do you mean by "expect the repairs to cost me". If you mean you plan to pay someone to repair it for you, consider that if it's a business who regularly deal with second hand lab equipment, they probably aren't interested in throwing money away and also have some basic technical and financial competence. If it $300 and they can sell it for $750 if it's repaired and the repairs are only likely to cost them $150, there's a fair chance they will either repair it themselves or sell it for at least $500.

In other words, it's actually quite difficult for it to be worthwhile if you're using the same commercial repair services as everyone else. So such repair required items often only makes sense either if the seller has no idea what they're doing (and you get lucky since you're competing with everyone else interested in realise the seller doesn't know) or you plan to do a big chunk of the repair work yourself. But to be honest, if you can't figure out how much it's likely to cost, there's a fair chance you probably shouldn't be doing the repair work yourself, particularly when dealing with a power supply.

Also how are you going to figure out if it's working properly and calibrated etc if you don't even have a working one to compare the results against and have limited idea what you're doing? (This applies even to a commercial repair service unless they provide this service themselves, and that's something not likely to come cheap.)

Further since it sounds like you actually need it rather than just being a toy you'd like to have, the risk is fairly high. Maybe the repairs end up costing more than expected or maybe there's more wrong than expected masked by ther other symptoms (well these are related but the point is you could end up with a situation where it's simply not worth repairing it). So now you have a $300 item which maybe you spent more money on and you still need to spend $750 and you're probably not going to even get $300 back for the item you bought if you're lucky.

In your situation such a risk doesn't seem to make much sense, especially since you're probably only going to be saving $350 at most. (You shouldn't need to look or ask to figure that if you're in a developed country it's going to cost at least $100 to pay someone to fix a machine like that. And probably a lot more when we consider the need for some testing or calibration.)

P.S. I'm sure I'm going to get in trouble for this, but if you plan to crowdfund in the future you really need to be able to figure these basic ideas out for yourself. While there's still a lot of weird stuff that happens if you're lucky, the crowdfunding market has also gotten a lot more wary now. If you sound like you have zero idea what you're doing, don't be surprised if your crowdfunding falls flat. Note also that a lot of what I'm saying is basically just what others like Dragons flight have said but in more detail.

Nil Einne (talk) 08:54, 17 June 2016 (UTC)

I don't think anyone should get in trouble for saying: "be careful" and/or "ask a professional". (((The Quixotic Potato))) (talk) 13:10, 17 June 2016 (UTC)

First of all, "ask a professional" ≠ "figure it out for yourself" -- and did I tell you that my forte is in engineering, not cost analysis? 67.164.54.236 (talk) 04:07, 18 June 2016 (UTC)

You don't have to be an expert in cost analysis to realize that "What will it cost?" depends on the answer to "What's wrong with the machine?" which would require visiting a repair shop to get an estimate. The real question should be "How much money am I willing to spend?" ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:11, 18 June 2016 (UTC)

True enough, but you can't very well get an estimate from a repair shop for a machine you don't have, can you? 67.164.54.236 (talk) 04:18, 18 June 2016 (UTC)

And you expect us to do better? Again, how much money are you willing to spend? One tip: If it's advertised "as-is" and/or non-returnable, be skeptical. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:45, 18 June 2016 (UTC)

I was hoping for a typical (average) figure for this kind of repair, at least within an order of magnitude -- but I'm leaning more toward buying the Nicolet instead. 67.164.54.236 (talk) 07:57, 18 June 2016 (UTC)

difference between web(unfinished?) version and published book

Hi I dont have access to following book: Metamorphic Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Metamorphic Rocks, ISBN-13: 978-0521336185.

I found "web version" on external link from 01/02/07. I am interested if there are differences between this version and published version on page 11, where use of ‘metamorphic/igneous’ ultramafic terms are discussed.

Thank you in advance Obradow (talk) 12:55, 16 June 2016 (UTC)

I'd be surprised if one of the relatively few of us happens to have that book handy to compare. But maybe I'll be surprised... May I ask what you intend to use this information for? Even if I were using this authority/ systematic convention for writing a serious scientific paper and naming rocks, I'd be comfortable using this pdf, and assuming it is either the same or better than the book. To be safe, I'd cite the pdf, not the book. The pdf and book both came out in the same year, and it is highly unlikely, in my opinion, that there are substantive differences. Sorry I can only offer opinion - since you're asking about one specific book it kind of limits our ability to give references! Also, I was not aware of SCMR, so thanks for the interesting question :) SemanticMantis (talk) 13:40, 16 June 2016 (UTC)

Lots of American university libraries own copies of this book (see [1]); if you'd asked this question two years ago, I would have been able to answer it easily. Nyttend (talk) 16:25, 16 June 2016 (UTC)

Lizard ID

a lizard

Does anyone know what species this one is? He lives on top of a 500m hill near Bratislava, Slovakia. I was hoping that the black spot behind the head would be characteristic, but it seems that several of the European lizards have them. Thanks, Henry^Flower 21:17, 16 June 2016 (UTC)

Might be Podarcis muralis. They are very common and widespread across Europe, so in that sense a parsimonious option as well. They come in lots of different morphs though, so you will see some examples that have rather different colors, though they will share other, more conserved morphological traits. Yours looks like this guy [2] to me. As for the dark spot: I'm not sure what you're referring to but if it's that depression on the side of the head, just in front of the neck, that's his ear [3]. SemanticMantis (talk) 22:30, 16 June 2016 (UTC)

Thanks -- those morphs are confusing, but fascinating! And yes, I meant his ear -- I really need to learn more about lizards. :) Henry^Flower 05:39, 17 June 2016 (UTC)

Cute lizard. The article doesn't indicate any harm to humans, but it also doesn't indicate what they eat. It's reasonable to suppose that they feed on insects, so having one as a pet might be advantageous. (Provided you don't have larger pets that might see the lizard as dinner.) ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:22, 18 June 2016 (UTC)

"Eat insects and other invertebrates" according to this. They are found in the UK but not native, however taking one from the wild would probably be in breach of the Wildlife and Countryside Act 1981, even though they are not scheduled. What the situation is in other European countries, I can't say. Alansplodge (talk) 19:37, 18 June 2016 (UTC)