Wikipedia:Reference desk/Archives/Science/2018 August 13

= August 13 =

Float gauges


What does one of these things look like when it's in good condition? We have no float gauge article, and the other images in Commons:Category:Level gauges don't look like they could be contorted into this shape. A Google Images search for "float gauge" returned a mix of images of dial-shaped displays (example) and images of glass objects (example), none of which I can imagine becoming shaped like this under any kind of pressure. NB, the image appears in Water hammer, where it's captioned "Effect of a pressure surge on a float gauge". Nyttend (talk) 00:54, 13 August 2018 (UTC)


 * The item in the photograph is a float gauge for an industrial application like a large fuel tank or a separating tank. (The image page has a caption that specifies this detail: this is a float gauge for a pressure-relief valve in a separator tank).  Here's a diagram from the horizontal separator article at the Schlumberger Oilfield Glossary.
 * Of course, separating tanks occur in all kinds of other industries as well: for example, we have an article on vapor–liquid separators.
 * You might use these as starting points to find more complete diagrams of similar float valves in fully-intact systems.
 * For example, you can buy a new float valve, also suitable for use in industrial propane systems or refrigeration systems, from this catalog: (Page 70): flange plate with float valve, from ESK Schultze, esteemed distributor of high-quality schwimmerventile.
 * Nimur (talk) 05:17, 13 August 2018 (UTC)
 * It is hard to imagine how one would get water hammer inside a separating tank.
 * I asked the person who uploaded the picture: --Guy Macon (talk) 05:34, 13 August 2018 (UTC)
 * You flood a closed rigid tank with an excessive flow rate inwards, which then creates a shock wave. Or you introduce a shock wave down one of its pipes (even backwards against normal flow). The fact it's a closed tank (it might even have been vented) doesn't mean that it can't have a float gauge in it. Andy Dingley (talk) 10:30, 13 August 2018 (UTC)


 * It's an easily manufactured, closed, sealed volume. Typically spherical or cylindrical, they used to be made from a pair of metal pressings (or spinnings), with a seam between them, rolled, soldered or welded.  For low pressures, most are now plastic and made by something like rotational moulding which can make an inherently closed volume. Andy Dingley (talk) 10:33, 13 August 2018 (UTC)
 * The appearance under the article "Water hammer" is quite suitable. Without the damage, the shape is a cylindrical with a curved upper and lower bottom. Pressure surges along a longer pipe system, also known as Joukowski shock can reach a considerable high pressure. The depicted objects was located in such a pipe system. --Cccefalon (talk • contribs) 19:22, 23 August 2018 (UTC)
 * On request of Guy Macon, I added an additional answer on my Userpage, see here. --Cccefalon (talk • contribs) 14:40, 16 October 2018 (UTC)

What place has the shortest average wait for sustained hurricane wind from tropical cyclones?
What about for the US? It must be somewhere in Florida or North Carolina. Worldwide, I'm guessing it's somewhere in Greater China, the Philippines or another West Pacific island. Each storm counts as one (getting 2 eyewalls and an eye doesn't count as 2) Sagittarian Milky Way (talk) 19:49, 13 August 2018 (UTC)
 * Let me reword your question. "We can calculate a location's average time from when it gets hit by one hurricane until it gets hit by another.  Where in the world is this average time shortest?"  Is this what you mean, or did I mangle it?  Obviously I saw the hurricane-force winds bit, so I know you don't want to count a storm if the outer bands hit, with sub-hurricane-force winds.  Nyttend (talk) 23:31, 13 August 2018 (UTC)
 * To reword it again, does the question not boil down to "Which places get the most frequent hurricanes?" Matt Deres (talk) 01:30, 14 August 2018 (UTC)
 * That question (obviously the one intended, based on next response) could be answered with "This place gets them every two years", but "shortest average wait" sounds to me like the standard deviation is low, i.e. they come at more regular intervals. Nyttend (talk) 04:06, 14 August 2018 (UTC)
 * Maybe I didn't think that one though. Below Philippines doesn't have much Coriolis effect, the hurricane wrecking mountains of Taiwan and the Philippines partially shield a lot of coast like Vietnam and Fujian and the Honshu elbow near Tokyo might be too north to have the record? There's also smaller islands like Okinawa and Guam that would have the benefit of not affecting circulation of approaching storms as much as the big mountainous landmasses like Taiwan (altitude: 13,000 feet) Sagittarian Milky Way (talk) 05:33, 14 August 2018 (UTC)
 * "Which places get hurricanes most frequently? (where hurricane is defined as getting close enough for hurricane force wind (1-minute average (some countries call them typhoons etc. and use longer averages))" Sagittarian Milky Way (talk) 03:10, 14 August 2018 (UTC)
 * This is becoming confusing. The first post mentioned tropical cyclones, which are a particular type of storm. In the US such events are called hurricanes. But a hurricane is also a wind speed, which can occur occur independent of a tropical cyclone. So I have no idea where this is going. HiLo48 (talk) 03:16, 14 August 2018 (UTC)
 * Only counting hurricane force wind caused by tropical cyclones. Sagittarian Milky Way (talk) 03:24, 14 August 2018 (UTC)


 * Does This help? -- Jayron 32 14:10, 14 August 2018 (UTC)
 * Taiwan is a significantly smaller target than a lot of the rest of the list and is 7th so Taiwan is certainly a candidate. #1 Mainland China had 127 storms in that time period but is a big target so who knows if any point of the Mainland beats all points of Taiwan. I'd be happy with narrowing the point down to a length of coast or archipelago the size of Luzon or the Marianas. Sagittarian Milky Way (talk) 20:32, 14 August 2018 (UTC)

What's the last vegetable here?
The leafy green "san choi" (Cantonese, represented by a character with three dots on the left signifying water, not lettuce) Thank you. 104.162.197.70 (talk) 22:06, 13 August 2018 (UTC)
 * I'm not getting anything from Google. The picture is not great; many leafy greens look broadly similar at a resolution like that, but if I had to hazard a guess it would be that it's baby spinach. I am less than useless at Cantonese; do any of the terms here make sense? Matt Deres (talk) 01:27, 14 August 2018 (UTC)
 * Possibly Basella alba also known as "Malabar Spinach, vine spinach, red vine spinach, climbing spinach, creeping spinach, buffalo spinach and Ceylon spinach". See figure 9. Our article says "潺菜, 木耳菜, 落葵 or 蚕菜, being saan choy, xan choy, shan tsoi, luo kai, shu chieh, and lo kwai in some of readings of Cantonese". Nil Einne (talk) 04:29, 14 August 2018 (UTC)


 * BTW same answer is suggested here for a similar sounding vegetable [//www.chowhound.com/post/identify-delicious-vegetable-638175] although I guess we already have what wikipedia says anyway. See also [//www.clovegarden.com/ingred/cn_malabarz.html] which has an image of the vegetable removed from the plant. (And also the same names etc.) Nil Einne (talk) 04:51, 14 August 2018 (UTC)