Wikipedia:Reference desk/Archives/Science/2024 January 22

= January 22 =

bad weather drones
This question is inspired by the recent incident of a guy freezing to death in the White Mountains (New Hampshire) in very windy, bad weather conditions because SAR helicopters couldn't fly safely in the storm, and rescuers couldn't get to him either.

'm wondering if there are drones that can fly in such conditions, or alternatively, whether there are serious technical obstacles to building them. Note that while in principle they should be expected to not crash during missions, the point of using a drone is that the risk tolerance is higher than it would be for a copter carrying humans. Also the drone can be smaller, and doesn't have to land in the snow: if it can drop a 5kg or 10kg payload at the location, that is probably enough to deliver some Duraflame logs and matches, or whatever else it would have taken to keep the person warm til the next day. While it was unusually cold for New Hampshire (single digit Fahrenheit, or well below 0 with wind chill), compared to say a Mount Everest expedition it sounded mild. I.e. from my uninformed perspective it seems like the guy would have been ok with the right gear.

I'm not connected to any SAR stuff or to the victim. It's just about understanding a news story. Thanks! 2602:243:2007:9330:15DA:CAD1:28F4:E61E (talk) 03:08, 22 January 2024 (UTC)


 * I searched for bad weather military drones and found this one. Modocc (talk) 06:04, 22 January 2024 (UTC)


 * British mountain rescue teams are beginning to work with drones, but as this paper points out, they are limited by law to only operate drones within Visual Line of Sight (VLOS), which rather negates their effectiveness. Alansplodge (talk) 12:16, 22 January 2024 (UTC)
 * The majestic and steadfast Saint Bernard is famous for rescuing travelers in peril on the snowy slopes of the Swiss Alps. Here are mountain dog breeds that may reach places that drones cannot reach. Philvoids (talk) 14:56, 22 January 2024 (UTC)
 * Civilian drones are limited to unobstructed visual sight here in the US too, but perhaps one of our delivery services will build drones that are equipped and operated safe enough to be exempt, especially for SAR uses. Last year, four companies applied for exemptions with the FAA. Modocc (talk) 18:37, 22 January 2024 (UTC)

Amount of elements in universe and Earth
Does the sequence of the atomic number of elements sorted by the amounts in the universe from high to low be 1, 2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 3, 4, 21, 22, 23, 24, …? How about in the Earth? In the Earth the sequence seems to be 8, 14, 13, …?

Also, which elements occur as free state in nature, and which elements occur as chemical compound in nature? I think that the only elements which occur as free state are 2, 7, 8, 10, 16, 18, 36, 44, 45, 46, 47, 54, 76, 77, 78, 79, 86, am I right? Since even some elements with low activity such as 14 and 29 also occur as chemical compound in nature. 36.233.233.71 (talk) 13:48, 22 January 2024 (UTC)
 * This table of the elements will help anyone investigate your question. The sequence that you assume applies in Earth is Oxygen, Silicon, Aluminium. Philvoids (talk) 14:42, 22 January 2024 (UTC)
 * More commonly we refer to elements by their names, rather than atomic number. And our article on this topic is "Abundance of the chemical elements". This has a different order for cosmic abundance. Your Earthly figures match those in "Abundance of elements in Earth's crust". For your second part of the question see native element mineral for occurrences in pure form. For gases they may be mixed even if the molecules only contain one kind of element, eg oxygen, nitrogen, and noble gases in the air. Even element 1 occurs as natural hydrogen on Earth. Graeme Bartlett (talk) 21:59, 22 January 2024 (UTC)
 * The native element mineral article looks pretty hard to read and seems to include things other than 'free state'. Better might be native metal. Note that both of these include alloys. Is that considered "an element in its free state, mixed with other things", for purposes of this discussion? DMacks (talk) 17:28, 24 January 2024 (UTC)

Max Planck and intensity of radiation
Reading "The theory of heat radiation" from Max Plank, I found the formula (9):

K=$$\int_{0}^\infty d\nu(K_\nu+K_\nu')$$

Then Max Plank write about this formula "it is seen that the quantity K$$_\nu$$, the intensity of radiation of frequency $$\nu$$, and the quantity K, is the intensity of radiation of the whole spectrumn are of different dimensions."

K being in watts per square meter, what is the dimension of K$$_\nu$$ and what kind intensity is it?

Malypaet (talk) 18:39, 22 January 2024 (UTC)
 * Kν is the "specific intensity" and has units of Watt per square meter per Hertz (or equivalent). --Wrongfilter (talk) 18:46, 22 January 2024 (UTC)
 * Ok, indeed we have $$d\nu K_\nu$$ in Watt per square meter, because $$d\nu$$ is in Hz. Malypaet (talk) 23:00, 22 January 2024 (UTC)

Bare electrode stick welding
I want to learn about bare electrode stick welding, ie without flux. Wikipedia tells us that coated electrodes were invented around 1900. So for nearly 100 years they welded without flux, yet I can find almost no information on this older technique. All I can find is this one forum thread from 2004 which talks about using a pine block to provide shielding to the bare electrode, and various other scattered mentions of "old timers" welding with car batteries and coat hangers. Can anyone point me towards old books from the era or whatever that discuss this method in detail? Gkarkp (talk) 19:09, 22 January 2024 (UTC)
 * The article you point to says "there was little development in electrical welding until Auguste de Méritens developed a carbon arc torch that was patented in 1881" and that "in 1885, Nikolay Benardos and Stanisław Olszewski developed carbon arc welding". So at most for 19 years people suffered with whatever that method entailed until "around 1900, Arthur Percy Strohmenger and Oscar Kjellberg released the first coated electrodes". I would guess that previous efforts involved mechanical means of feeding flux and/or shielding onto the growing weld. Abductive  (reasoning) 02:47, 23 January 2024 (UTC)

Time zone questions
These questions are questions that I have thought quite a long time and are not homework.


 * 1) Why Belarus switched to Moscow time in 2010? Why they don't use Eastern European Time?
 * 2) Why western Russia (St. Petersburg) has always been in UTC+3, rather than its natural time zone UTC+2? Why St. Petersburg has always been in same time zone as Moscow? --40bus (talk) 19:32, 22 January 2024 (UTC)


 * Belarus stopped doing the Summer Time/DST thing in 2010, and went on the equivalent of year round EEST. Here's a neat map of deviations between solar time and standard time. http://blog.poormansmath.net/images/SolarTimeVsStandardTime.png --jpgordon&#x1d122;&#x1d106;&#x1D110;&#x1d107; 21:20, 22 January 2024 (UTC)
 * That's a really neat map! Thanks for posting it. DMacks (talk) 17:13, 24 January 2024 (UTC)

Data mittens
What are data mittens? Thank you. 86.187.226.242 (talk) 22:52, 22 January 2024 (UTC)


 * Wired gloves AKA datagloves? Modocc (talk) 23:09, 22 January 2024 (UTC)
 * Or mittens to handle data kittens? --Lambiam 08:50, 24 January 2024 (UTC)
 * "Handy" if you take a virtual walk through Beatrix Potter land? Martinevans123 (talk) 09:56, 24 January 2024 (UTC)
 * Cheap knockoffs of data gloves, probably made by Guccy. Clarityfiend (talk) 13:30, 25 January 2024 (UTC)