Wikipedia:Reference desk/Archives/Science/2020 September 22

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September 22

Moonwalk suits in c. -100°F and brutal katabatic wind on Earth

How effective is the Apollo moonwalking suit for Earth, Mars and LEO? It's very heavy and they walked in mild temps but if you're just sitting or lying down in 100 mph gusts on top of Everest in winter how would the discomfort vs continuous duration graph compare to Luna? Let's pretend there's a helipad and shack at the top that's room temperature and pressurized so you start feeling 100% but with lowlanders' oxygen needs. What about Antarctica's worst windchill under hurricane force, or good and bad Martian weather? Or those marathon modern spacewalks? Sagittarian Milky Way (talk) 00:12, 22 September 2020 (UTC)

Let's also pretend Mount Everest is less than half as high as it is, since one would not be able to operate a helipad even in low-wind conditions at a height of 29,000 feet (8,800 metres).  --Lambiam 10:51, 22 September 2020 (UTC)

Didier Delsalle literally landed at the tip. Sagittarian Milky Way (talk) 14:54, 22 September 2020 (UTC)

There have been some helicopter rescues on Mt. Everest about 6000 meters.[1] The 1996 rescue of Weathers and Gau at 6200 meters mentioned in that link is also detailed in Jon Krakauer's book Into Thin Air. 2601:648:8202:96B0:0:0:0:DDAF (talk) 06:20, 23 September 2020 (UTC)

Spacesuits, including the Apollo version used on the moon, are built to solve the opposite problem: they have to get rid of body heat. See Apollo/Skylab space suit and Liquid cooling and ventilation garment. It would be easy to add some heaters, but I don't think a spacesuit actually has them. The Primary life support system ("backpack") contains electronics, circulating water, and breathing air systems that would not function under those conditions. Worse, the pressure suit has flanges and other items that would provide a large thermal conductance to the environment in some places. I suspect the pressure helmet and neck ring would get very cold, and possibly break because of differential thermal contraction. The gloves have silicone fingertips that would freeze at -67°C. Summary: not a good choice. --Amble (talk) 23:00, 23 September 2020 (UTC)

Yep, this is a good example of how human intuition—which of course is "designed" for our comfy Earth environment—is misleading when it comes to space. Space is a vacuum, and vacuum is an ideal insulator because there's nothing to convect heat away. Your problem is getting rid of heat, not keeping it in. Manned spacecraft (and a spacesuit is really just a one-person spacecraft) boil away a working fluid to get rid of excess heat; the ISS uses ammonia. Spacesuits also have components that generally aren't needed on Earth, such as protection against radiation and micrometeorites. --01:24, 24 September 2020 (UTC) — Preceding unsigned comment added by 47.146.63.87 (talk)

Types of vets

If there are many types of physicians practicing human medicine, are there as many types of vets also? Our fellow mammals such as cats and dogs have organisms basically as complex as ours, after all. --Qnowledge (talk) 00:28, 22 September 2020 (UTC)

There are specialized parrot veterinarians, for sure. 146.200.128.134 (talk) 07:15, 22 September 2020 (UTC)

According to Veterinarian#Focus_of_practice there are (at least) eleven specialities. (According to the disambiguation page at vet there are ten types of vet.)--Shantavira|^{feed me} 07:47, 22 September 2020 (UTC)

There are the (US-based) Association of Reptile and Amphibian Veterinarians (who I believe are themselves mammals but treat animals in the Sauropsida clade), and The American Association of Fish Veterinarians. Some people keep a tarantula as their pet, but I did not readily find vets specializing in arthropods. I see some hints of people taking veterinarian psychiatry classes, but no substantial evidence that such classes are being offered, or of people practicing veterinarian psychiatry.  --Lambiam 08:11, 22 September 2020 (UTC)

The list of Veterinary specialties has some animal groups not yet specifically mentioned here.  --Lambiam 08:16, 22 September 2020 (UTC)

To really compare specialisations in vets with those among human doctors, we would be looking at those who specialise on different parts of animal anatomy. A few years back my dog had some expensive treatment from an orthopedic veterinary specialist. But, in the spirit of of having an article on everything, we have Veterinary specialties. It has a very long list of specialties. I've also encountered dog and cat psychologists. HiLo48 (talk) 08:32, 22 September 2020 (UTC)

I knew someone who got a prozac prescription for her neurotic cat (not sure whether it was from an ordinary vet, or a cat psychiatrist, or what) and the treatment mellowed the cat out quite a lot, even after being tapered off after a while. At the other end of the scale Dr. Igor Smirnov, DVM is one of the co-authors of the paper announcing discovery of the meningeal lymphatic vessels. His part in the discovery was doing a bunch of intricate brain surgery on mice. I could only think that surgery on humans must be trivial compared to that. The whole discovery was amazing. 2601:648:8202:96B0:0:0:0:DDAF (talk) 06:30, 23 September 2020 (UTC)

Perhaps that vet can prescribe Ritalin for my hyperactive chihuahua, who seems to have an attention deficit.  --Lambiam 11:49, 23 September 2020 (UTC)

P vs V(isotherm) graph of real gas with critical temperature and critical pressure marked.

I want a P vs V graph for some real gas(say, CO₂), which shows the plots on a few temperatures, with plot at critical temperature as well, for comparison. I also want to have the representation of critical pressure on that very same graph. Also included should be the plot for Triple point temperature, with explanation for why the graph is that way. To sum up, there should also be a plot of the P vs V graph at Boyle's temperature.(fyi P= pressure, V= volume). Graph could be like this one:

— Preceding unsigned comment added by 16AdityaG09 (talk • contribs) 04:00, 22 September 2020 (UTC) <<clear}}

There are plots for CO₂ in the same Commons category as that one. Unfortunately they are jpegs and pngs rather than svgs. catslash (talk) 23:59, 22 September 2020 (UTC)

Correction: This one is svg, so you can easily change the language of the labels if you wish, or change °C to K, or re-label the y-axis in MPa if you don't like bar. catslash (talk) 00:12, 23 September 2020 (UTC)

Fortunately this SVG uses <text>...</text> for the text, which makes the editing of the text very easy. Many SVG on commons (and in the world in general) use graphical paths for text, which is only slightly easier to edit than a plain PNG. DMacks (talk) 13:45, 23 September 2020 (UTC)

Also, since it was created in Inkscape, it is very simple to open it again in that app and edit it there, which is easier than playing with the .svg file directly if you are not so familiar with editing such files. Michael D. Turnbull (talk) 14:14, 23 September 2020 (UTC)

If you do translate it, please consider uploading it to commons so others can benefit as well. See commons:Help:Translation tutorial#SVG_files for several technical ways if you don't have Inkscape. DMacks (talk) 14:29, 23 September 2020 (UTC)

Carbon dioxide isotherms-en

As I'm fairly new to Inkscape, I tried this myself and uploaded the English version to Commons, as now coped here. I used the option to output the file in what Inkscape calls their optimised format, which reduces the file size and makes it much easier to use a text editor to make further alterations. Michael D. Turnbull (talk) 15:08, 23 September 2020 (UTC)

Nice! I renamed your file to "-en", per wiki-world standard to use two-letter language-codes, and fixed capitalization of "kg" in the x-axis also. There are a ton of spacing nits due to different SVG engines having inconsistent handling of superscript:( DMacks (talk) 03:58, 24 September 2020 (UTC)

Liquid elements

At what temperature are the most elements on the periodic table in liquid form?

User:Heyoostorm^_talk! 17:39, 22 September 2020 (UTC)

@Heyoostorm: It may depend on pressure, as we learn from the example of water (Water#Triple and critical points). --CiaPan (talk) 17:46, 22 September 2020 (UTC)

Fair point, let's say normal atmospheric pressure. User:Heyoostorm^_talk! 17:49, 22 September 2020 (UTC)

At 2609-2673K there are 44 liquid elements, also 44 between 2719-2742K and 2750 to 2792K. (Data from List of chemical elements), ignoring post-actinides. Graeme Bartlett (talk) 22:50, 22 September 2020 (UTC)

Also it depends on allotropes for example white phosphorus melts lower than other forms. Graeme Bartlett (talk) 23:06, 22 September 2020 (UTC)

As Graeme Bartlett notes, we don't really know because no one has ever had enough of the heaviest elements to measure their melting points. In fact, we have the same problem with things like francium. Double sharp (talk) 07:20, 23 September 2020 (UTC)

Indeed, something like 1/5 of known elements we have never had enough atoms together in one place to take a reliable melting point. --Jayron32 11:38, 23 September 2020 (UTC)