Wikipedia:Reference desk/Archives/Science/2016 June 11

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June 11

Acid pump

Help! I'm looking for a compact, acid-resistant and not too expensive centrifugal pump for an experimental application, but I can't get a quote or even a comparison anywhere without having to enter the company name! I'm not actually affiliated with a company, but am doing the experiments on my own time (or planning to -- I can't get started until I get the pump) -- what should I do? 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 04:15, 11 June 2016 (UTC)

try aliexpress. I'd be more helpful but since your spec is virtually undefined (pH, head, flow rate, etc) then i won't be. Greglocock (talk) 04:38, 11 June 2016 (UTC)

Thanks! And here's the more detailed spec: I'm looking for a pump which can circulate small quantities (<1 L) of dilute phosphoric acid (10% or less) at VERY high pressures (head of 100 m or more). Oh, and it has to run on 60 Hz AC. 2601:646:A180:C88C:7465:D06A:8B2E:A8BD (talk) 04:45, 11 June 2016 (UTC)

I'd be looking at a food processing pump, 10% phosphoric is not scary, and your pressures are pretty trivial. I'd expect a peristaltic pump with silicone tubing would do. BUT. I am not a professional chemist. I have never specced a food industry pump in my life. http://www.welco.net/product/wp1000_1100/wp1000_1100_guide.html So if that is helpful, great, if not, oh well. Greglocock (talk) 05:17, 11 June 2016 (UTC)

That's helpful, but I'd strongly prefer a centrifugal or axial pump -- the downstream setup is a packed-bed reactor which I expect will routinely clog up (in fact, it will be set up for batch operation only due to the product forming a crust and blocking the flow), and in such a setup a positive-displacement pump of any sort could be positively dangerous. Also, if there are pumps which develop even higher pressures, I'd like to see them -- but if not, then 10 bar probably would do. 2601:646:A180:C88C:7465:D06A:8B2E:A8BD (talk) 05:52, 11 June 2016 (UTC)

On second thought, I've looked at the specs, and they do not specify the head -- but they do say the pump should be mounted no more than 2 m above the inlet. If this has to do with the pressure, then it follows that the working pressure is only 0.2 bar or so, and that will NOT do -- I need probably at least 10 bar (corresponding to a head of 100 m), maybe more. 2601:646:A180:C88C:7465:D06A:8B2E:A8BD (talk) 06:01, 11 June 2016 (UTC)

Don't confuse intake pressure and output pressure. http://www.shanleypump.com/corrosive_and_acids_resistant_centrifugal_pumps.html say. Greglocock (talk) 06:57, 11 June 2016 (UTC)

They have PRECISELY what I'm looking for! Thanks a million! Now I just hope I can afford it... 2601:646:A180:C88C:7465:D06A:8B2E:A8BD (talk) 08:22, 11 June 2016 (UTC)

You could try entering freelance or N/A in the company name field. Worst that's likely to happen is they'll ignore you because they don't think your worth dealing with. Nil Einne (talk) 06:31, 11 June 2016 (UTC)

*you're AllBestFaith (talk) 13:39, 11 June 2016 (UTC)

Given your concerns about clogging the downstream system, you'll want to check the pump's specs (or sales rep) about the risks of "deadheading" (running with outflow blocked). I assume you've already planned for a way to monitor and relieve pressure:) On additional concern for the intake pressure (or height above supply) relevant to centrifugal pumps is that (to quote our article) "Most centrifugal pumps are not self-priming." DMacks (talk) 10:09, 11 June 2016 (UTC)

Bubbles

What causes the sound of bubbles popping? JoshMuirWikipedia (talk) 11:01, 11 June 2016 (UTC)

The surface tension of the liquid slightly pressurizes the interior, and when the layer of liquid goes away suddenly, the gas in the interior expands rapidly with a "pop" sound. --Guy Macon (talk) 12:50, 11 June 2016 (UTC)

Is it the same thing for balloons? It just occurred to me something I heard a while ago about latex exceeding the sound barrier, though I'm not sure if I heard it right. Thanks for your answer though! JoshMuirWikipedia (talk) 13:28, 11 June 2016 (UTC)

This article may be interesting to you. For more detailed information see here The Quixotic Potato (talk) 17:27, 11 June 2016 (UTC)

Confusion about mumps and measles

Mumps and measles has different symptoms but causative virus is same for both. How? — Preceding unsigned comment added by Achyut Prashad Paudel (talk • contribs) 13:12, 11 June 2016 (UTC)

Measles is caused by the Measles virus. Mumps is caused by the Mumps virus. Still confused? AllBestFaith (talk) 13:28, 11 June 2016 (UTC)

Agreed. The measles virus and mumps virus are not the same. The MMR vaccine is a multi-vaccine mixture which vaccinates against both these and the rubella virus, but that's an accident of history, not a sign that they are the same causative agent. -- The Anome (talk)

International Journal of Advanced Research (IJAR), a credible journal?

International Journal of Advanced Research (IJAR) claims on its website to have an impact factor of 5+. www.journalijar.com/Journal website Is this journal reliable and acceptable in academic circles or is it a paid publishing journal? I am curious why this article clai?medly publishing about a new species of plant got published in this journal. Can somebody help? — Preceding unsigned comment added by 117.253.199.233 (talk) 14:17, 11 June 2016 (UTC)

WP:RSN is the best place for this sort of question, but my non-expert answer is "probably not" - see this forum posting. Note also that we do not have an article on the journal, and details of its publisher do not seem to be immediately available. Tevildo (talk) 15:36, 11 June 2016 (UTC)

The journal's subject matter is incredibly broad -- agriculture to psychology to astronomy and everything in between. This raises a huge red flag. Shock Brigade Harvester Boris (talk) 15:48, 11 June 2016 (UTC)

Agreed. The journal is also on Beall’s List of Predatory Publishers 2016[1] DrChrissy ^(talk) 16:22, 11 June 2016 (UTC)

Being on the List of Predatory Publishers is a red flag, being very broad in topic/scope is not in itself, a cause for suspicion. Most of the absolute top journals (Science, Nature, Proc. Roy. Soc., PNAS, etc.) do in fact publish on everything from agriculture to psychology. So does PLoS ONE for that matter. SemanticMantis (talk) 13:22, 13 June 2016 (UTC)

WOT Services rates the site's trustworth Very Poor. —Tamfang (talk) 03:43, 12 June 2016 (UTC)

"R^deloc" in a chemical formula

The compound [(R^delocSn)₄S₆](R^deloc=4–(CH2=CH)–C₆H₄) is mentioned at [2] and presumably [3] (though I don't presently have access). I assume there is some kind of electron delocalization implied there, but I've never seen this format and I don't know what it means. The illustration in the sci-news article doesn't even look like it has the phenyls the right way around (wait, no, I get that part now, the 4-(CH2=CH) is just another constituent, not the attachment site), but then again, how can I say that when I don't understand the formula? Wnt (talk) 14:53, 11 June 2016 (UTC)

Certainly an odd way to represent a 4-vinylphenyl substituted Sn atom with a Sn₄S₆ core. [(p-CH₂=CH-C₆H₄-Sn)₄S₆] would be clearer. EdChem (talk) 15:58, 11 June 2016 (UTC)

The underlying Science ref does indeed identify it as R^deloc as mentioned in the sci-news.com highlight. EdChem is correct on its meaning according to the 3D diagrams included in both links. As final confirmation, the supporting material for the Science article says the starting material is "Trichloro(4-vinylphenyl)tin (R^delocSnCl₃, R^deloc = 4-(CH₂=CH)-₆H₄)" and similar naming for the other related compounds they synthesized. DMacks (talk) 18:33, 11 June 2016 (UTC)

OH! The parenthesis and the equals sign (not double bond) were simply a definition. Well I... I shoulda seen dat. Thanks! Wnt (talk) 22:29, 11 June 2016 (UTC)

Checking Biophysics calculation of cardiogram

The question that I got is: What is the value of a point (1 mm square) horizontally in seconds or milliseconds if the recording speed of the cardiograph is 50 mm/s, 25 mm/s? My answer is: Each big square is equal to 5mm which are divided to 5 small squares of 1mm. and in calibration of 25mm/s it equals to 0.04 sec or 40 ms therefore: 40/5= 8ms. In calibration of 50mm/s we have to multiply the aforementioned value of 25mm/s and therefore it equals to 16ms. (8ms*2=16ms). My answer is correct? 93.126.88.30 (talk) 15:45, 11 June 2016 (UTC)

It's simpler than that. At 50 mm/s, one square is 1/50 = 0.02 s = 20 ms. At 25 mm/s, one square is 1/25 = 0.04 s = 40 ms. 25 mm/s is the standard speed - see Electrocardiograph. Tevildo (talk) 16:32, 11 June 2016 (UTC)

Thank you. Then I see that mistake was that I multiplied instead of dividing. Am I right? 93.126.88.30 (talk) 16:13, 12 June 2016 (UTC)

The basic equation is $v={x \over t}$, where $v$ is the speed (mm/s), $x$ is the distance (mm), and $t$ is the time (s). We know the distance (x = 1 mm) and the speed (v = 50 mm/s or v = 25 mm/s), so the equation we need to calculate the time is $t={x \over v}$. There are two mistakes in your calculation - you've divided instead of multiplying when calculating the time for a large square: one large square at 25 mm/s is 40 * 5 = 200 ms, not 40/5 = 8 ms, and you've multiplied by 2 rather than dividing by 2 when converting from 25 mm/s to 50 mm/s. Tevildo (talk) 22:18, 12 June 2016 (UTC)

Thank you for the explanation! 93.126.88.30 (talk) 00:44, 14 June 2016 (UTC)

Claim that Pando (tree) is the oldest living organism

Some IP changed the text:

"The root system of Pando, at an estimated 80,000 years old, is among the oldest known living organisms."

to:

"The root system of Pando, at an estimated 80,000 years old, the oldest known living organism."

Is that true? I think the original version is better. The edit could not be undone due to conflicting intermediate edits; it has to be fixed manually.

TIME claims that the Posidonia sea grass meadow may be 100,000 years old! [4] The Quixotic Potato (talk) 16:02, 11 June 2016 (UTC)

Link for the sea grass meadow: Posidonia oceanica. clpo13_(talk) 16:06, 11 June 2016 (UTC)

The linked list of long-living organisms seems to quite thoroughly indicate that no one knows what is the "oldest living organism", or for that matter how to define "oldest living organism", so I agree that the edit is inaccurate. There isn't even a hard-and-fast definition of life. Whether viruses are alive is debated. If you want to define things loosely enough you could argue all life is just part of a single thing that's been around for about four billion years since the last universal ancestor. --71.110.8.102 (talk) 23:34, 11 June 2016 (UTC)

Basically, the question of how long DNA has existed. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:14, 12 June 2016 (UTC)

Thanks, I have reverted back. Maybe the edits by 24.151.43.14 were useful but I am unsure, can someone please check that? The Quixotic Potato (talk) 01:29, 12 June 2016 (UTC)