Wikipedia:Reference desk/Archives/Science/2018 January 19

= January 19 =

What's a cryogel?
Hi. The word "cryogel" appears in various WP articles but doesn't have its own article or redirect. There's also no Wiktionary entry, and I ask as someone who works on Wiktionary. Could someone give us a quick but clear definition we can use, that distinguishes a cryogel from other things (gel, aerogel, xerogel, whatever)? Thanks! Equinox ◑ 06:56, 19 January 2018 (UTC)


 * I can't seem to find an explicit definition of the word, but the various things I find that are referred to as "cryogels" have in common that they are made by first dissolving something in a solvent, and then freezing and thawing until it polymerizes. Someguy1221 (talk) 07:19, 19 January 2018 (UTC)


 * Cryogel seems to be a registered trademark. What would be the inclusive uncapitalised term?  I suppose the word might enter the language as a normal term like hoover and vaseline.   Dbfirs  08:12, 19 January 2018 (UTC)
 * This is the website of the company which manufactures it, with plenty of details . Here is a definition from a technical glossary which might be a basis if you wanted to write something, but that is Russian, and elsewhere there might be trademark issues. Wymspen (talk) 10:11, 19 January 2018 (UTC)


 * Thanks for the feedback! So I gather it might be a trademark. But if ya look at Google Books you can see a lot of apparently generic talk about "cryogels". The plural and lack of caps suggests maybe the writers often see it as a generic term. Equinox ◑ 10:20, 19 January 2018 (UTC)
 * Found a review of the biological applications, which describes them as "macroporous gels produced at subzero temperatures (known as cryogels)". Klbrain (talk) 00:55, 20 January 2018 (UTC)

Current uses of radium-226
Does anyone actually still use radium-226 for anything? (That's the most stable isotope, which used to be the common one used; I know 223Ra is used as a radiopharmaceutical). The sources in our radium article on current uses are from last decade, and even then those uses were being supplanted: we usually use other isotopes (e.g. 192Ir, 60Co) for industrial radiography instead, and we usually use actinides (Pu, Am, Cf) for neutron sources instead of Ra. Is the main use of 226Ra really just to get rid of it by transmutation to 227Ac, like Ullmann's Encyclopaedia said in 1993? Double sharp (talk) 13:01, 19 January 2018 (UTC)


 * According to this the main use is the production of radon. Mikenorton (talk) 13:25, 19 January 2018 (UTC)
 * That's interesting, though I'd like to see where they got that information from. At first glance it seems to me a bit overdoing it to produce pure Ra specifically to get Rn: you can get Rn from anything above it in its decay chain quite easily (it's a gas, while its parents aren't, so the separation is trivial), so isn't a chunk of uranium ore already a serviceable radon source? Double sharp (talk) 13:49, 19 January 2018 (UTC)


 * For uses of Radon see Radon, although it doesn't look like it gets much use these days, for production see Radon, which supports it being produced normally from radium, even if the need for it is not great. Mikenorton (talk) 16:35, 19 January 2018 (UTC)