Wikipedia:Reference desk/Archives/Science/2023 May 16

= May 16 =

Is there such a thing as a totally noiseless refrigerator?
Is there such a thing as a totally noiseless refrigerator?

A refrigerator which doesn't not make any noise at all. 100% noiseless refrigerator. Zero noise.

A refrigerator which is compressorless (no compressor) and maybe also fanless (no fan).

Is there such a thing at least under research if not in retail markets?

Please refer me to an article or share some data. Thanks a lot. 2A10:8012:17:CDC6:9584:54AE:7AE6:F8E7 (talk) 07:11, 16 May 2023 (UTC)


 * Have a look at Einstein refrigerator. Dolphin ( t ) 07:30, 16 May 2023 (UTC)


 * The Einstein refrigerator is an example of an Absorption refrigerator. I'm familiar with these from what we called gas refrigerators here in Australia, in places without mains electricity. These use a real gas to burn, not the stuff Americans put in their cars, which of course is normally a liquid, not a gas. They are silent. HiLo48 (talk) 07:38, 16 May 2023 (UTC)
 * Oh, I live in Israel and from a quick check, no absorption refrigerators available here. If I want to buy something readily available and warranted, I need to pick a new regular refrigerator and to do some research to ensure that it's less noisy as possible (for example, having just one small compressor?). 2A10:8012:17:CDC6:9584:54AE:7AE6:F8E7 (talk) 07:52, 16 May 2023 (UTC)


 * The term "gasoline" originated in Britain in the 1800s, and "petroleum" was Anglo-French from a few hundred years ago. Commonly abbreviated to "gas" and "petrol". ←Baseball Bugs What's up, Doc? carrots→ 12:21, 16 May 2023 (UTC)


 * There are refrigerators based on thermoelectric cooling using the Peltier effect. These are usually small, able to contain a couple of cans of soft drink, sometimes running on USB power.  There are somewhat larger ones, e.g. "mini bar" types.  These may not be entirely silent, as they can use a small fan to cool the Peltier element.  The downside of Peltier devices is that they consume several times the electric power of a compressor refrigerator. 85.76.41.21 (talk) 10:47, 16 May 2023 (UTC)
 * Even with fan, these can be very quiet. Graeme Bartlett (talk) 10:54, 16 May 2023 (UTC)


 * My first fridge only made noise when the compressor ran. It had one compressor and was rather quiet. It make a soft "tink-tink-tink" sound. My newest fridge makes a chunking noise when the freezer compressor runs, a swooshing sound when the fridge compressor runs, a clanking and rattling sound when the ice maker runs, and a whistling sound when the water pump runs. As far as noise goes, fridge technology has gone backwards. 12.116.29.106 (talk) 12:21, 16 May 2023 (UTC)
 * Icebox. You might get the occasional dripping sound. Bazza (talk) 12:25, 16 May 2023 (UTC)


 * My family had one ages ago which ran on kerosene. Quite amazing that it could cool stuff by running a fire! It wasn't absolutely quiet but as near as makes no difference. NadVolum (talk) 16:40, 16 May 2023 (UTC)
 * That would have probably a version of an Absorption refrigerator that I mentioned above. HiLo48 (talk) 21:16, 16 May 2023 (UTC)


 * You could try an old-fashioned, icebox, which is silent (assuming the iceman cometh quietly). 136.56.52.157 (talk) 18:56, 16 May 2023 (UTC)

Dual Perceptrons
It's my understanding that Rosenblatt includes two kinds: logical and temporal. This seems important, but if it's in the article it's obscure to me. Can anyone point to a cite and suggest how to give this aspect of the theory its due. Thanks. Temerarius (talk) 15:17, 16 May 2023 (UTC)


 * I can't find anything in the literature about temporal perceptrons. There are publications about spatiotemporal perceptrons,which are not so much a special kind, but perceptrons used in learning to recognize [[wikt:spatiotemporal|spatiotemporal] patterns. --Lambiam 10:51, 17 May 2023 (UTC)

Can a subatomic particle annihilate with antimatter particle that isn't its antiparticle?
For example, what if an electron collides with an antimuon or an antimeson? will any annihilation take place, or what will happen if not annihilation? Rich (talk) 17:52, 16 May 2023 (UTC)
 * So, the answer is "nothing in particular". This is because there's nothing fundamentally different between anti-matter and matter in the sense of its properties.  Annihilation covers the details.  The reason for this is because annihilation happens because of the various conservation laws surrounding the quantum numbers of the particles.  In a normal collision (or in situations where two particles interact to make a new, third particle) all of the quantum numbers have to be conserved both before and after the interaction.  Since those are non-zero, there exists some particle with those quantum numbers. In the specific case of a particle-antiparticle pair, literally every one of the quantum numbers is now exactly zero; which means it doesn't exist as such.  The only thing left that hasn't cancelled is the energy and momentum, and energy/momentum which has no particle to which it is assigned is a photon.  -- Jayron 32 18:05, 16 May 2023 (UTC)
 * That interaction is sometimes described as an "annihilation", , according to the second link (slide deck from 2014), it has not been observed. What usually happens instead is that the muon simply decays. There are some models with particles beyond the standard model of particle physics that can't simply decay, but can "coannihilate" in pairs to produce standard model particles: see for example . --Amble (talk) 20:10, 16 May 2023 (UTC)
 * It can be regarded as annihilation in some sense because, while the electron and muonic leptonic charges must still be conserved separately, this can result in birth of a electron neutrino and a muonic antineutrino. The same goes (for instance) for proton-antineutron annihilation. Ruslik_ Zero 20:42, 16 May 2023 (UTC)
 * It should be noted that such an annihilation still meets the basic understanding of particle-antiparticle annihilation as protons and neutrons are composite particles, and so a proton is composed of 2 up quarks and a down quark, while an antineutron is one anti-up quark and two anti-down quarks. Such an interaction would result in a meson composed of an up quark and an anti-down quark, aka a Rho meson, ρ+.  Such mesons are better known as one of the virtual force carriers in the nuclear force, but as real particles, they can exist for a tiny fraction of a second before decaying into pions, which also decay after a tiny fraction of a second into muon and a muon neutrino, the muon then decays into an electron, and anti-electron neutrino, and another muon neutrino.  So, if I am doing my math right (and there's a large non-zero chance I am not) then proton-antineutron annihilation results ultimately in an electron and a bunch of different kinds of neutrinos as the final stable products.  -- Jayron 32 12:06, 17 May 2023 (UTC)
 * I may have flipped a sign in there somewhere; it may actually be a positron at the last step, now that I'm thinking about it, as charge still needs to be conserved. -- Jayron 32 12:09, 17 May 2023 (UTC)
 * That's it. ρ+ becomes π+ becomes μ+ becomes e+.  Should have been an anti-muon above.  -- Jayron 32 12:11, 17 May 2023 (UTC)

Can energetic muons colliding with uranium 235
or other fissionable nuclei trigger fission? If so, could it have scientific or practical applications? Rich (talk) 23:03, 16 May 2023 (UTC)
 * Maybe not? 136.56.52.157 (talk) 00:28, 17 May 2023 (UTC)
 * An energetic particle of any type colliding with any heavy nucleus (fissile or not) can cause it to fission. Ruslik_ Zero 19:59, 17 May 2023 (UTC)