Wikipedia:Reference desk/Archives/Science/2015 June 29

Science desk
< June 28	<< May | June | Jul >>	June 30 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

June 29

Identify a submarine

This photo of a submarine was found among a collection of documents and photos related to a South African warship, HMSAS Transvaal's trip to Australia in 1951. Unfortunately there is no other information about the encounter with the submarine, though we suspect it was probably Australian. Roger (Dodger67) (talk) 06:39, 29 June 2015 (UTC)

The silhouette is very similar to a British T-class submarine, a number of which operated from Australia during and after the war. WegianWarrior (talk) 07:00, 29 June 2015 (UTC)

A quick bit of research on Wikipedia suggests the Royal Australian Navy had no submarines in 1951. See Royal Australian Navy Submarine Service#1945 to present. (In fact, the RAN had no submarine from April 1931 when HMAS Otway (1927) and HMAS Oxley (1927) were returned to the RN, until HMAS Oxley (S57) et al were commissioned in the late 1960s.) Dolphin (t) 07:07, 29 June 2015 (UTC)

Thanks this info narrows down the research task considerably: Which Royal Navy T-class subs were in Australian waters during January 1951. Roger (Dodger67) (talk) 09:28, 29 June 2015 (UTC)

A March 1951 newspaper report of a Commonwealth naval exercise in Australian waters, in which two unnamed British submarines "acted as hares" for the combined surface fleet; Modern Submarine Main Danger. It might be difficult to pinpoint as the RN maintained a whole submarine flotilla at Singapore during the 1950s and early 1960s. Alansplodge (talk) 10:10, 29 June 2015 (UTC)

It was called "Operation Convex" according to The West Australian, 12 March 1951: "Big Naval Exercise". Alansplodge (talk) 12:05, 29 June 2015 (UTC)

Another photo of the sub has turned up, in Sydney Harbour, date not known but definitely early 1951. If anyone is interested, a forum discussion about the HMSAS Transvaal documents and photos is at http://www.saairforce.co.za/forum/viewtopic.php?f=18&t=8225&p=103962#p103962 -- Roger (Dodger67) (talk) 10:45, 29 June 2015 (UTC)

Just found that the Royal Navy's 4th Submarine Flotilla was based at HMAS Penguin in Sydney, the last British submarine leaving in 1969. According to The Royal Navy 4th Submarine Squadron Based in Sydney, AUSTRALIA, those based there in 1951 were: HMS Telemachus (P321), HMS Thorough (P324) and HMS Taciturn (P314). Alansplodge (talk) 12:25, 29 June 2015 (UTC)

But we can rule out HMS Taciturn, as she had been modernised in 1948 to look like this. Alansplodge (talk) 18:07, 29 June 2015 (UTC)

Thanks all I think the three names are as close as we're ever going to get unless another photo showing a hull number or other distinctive marking turns up. Roger (Dodger67) (talk) 18:06, 29 June 2015 (UTC)

What is relation of the bacterium "Helicobacter pylori" to the pylorus?

I don't find the answer In the article Helicobacter pylori "The bacterium was initially named Campylobacter pyloridis, then renamed C. pylori (pylori being the genitive of pylorus, the circular opening leading from the stomach into the duodenum, from the Ancient Greek word πυλωρός, which means gatekeeper.[110]). When 16S ribosomal RNA gene sequencing and other research showed in 1989 that the bacterium did not belong in the genus Campylobacter, it was placed in its own genus, Helicobacter from the ancient Greek hělix/έλιξ "spiral" or "coil".[110]" 192.117.186.252 (talk) 14:34, 29 June 2015 (UTC)

Found in the stomach, named for a part of the stomach? DMacks (talk) 17:07, 29 June 2015 (UTC)

Well, the article states that it is linked to duodenal cancers, leading to me to assume it's found in the duodenum as well as the stomach. It seems entirely reasonable that it was named pyloridis/ pylori simply be because of where it was first found, around the bottom of the stomach, top of the duodenum, in particular the pylorus. But that's just my guess' at present.

Now, for a reference that supports the claim, I got to this article [1] by searching for /pyloridis new/. That led me to the original describing article UNIDENTIFIED CURVED BACILLI IN THE STOMACH OF PATIENTS WITH GASTRITIS AND PEPTIC ULCERATION paywalled here [2] (you might be able to find an accessible copy by searching the title). In it, Marshall says

“ If

it is premature to talk of "Campylobacter pyloridis" perhaps the name "pyloric campylobacter" will do to define the site where these organisms are commonly found and to indicate the similarity to known Campylobacter spp.

”

- emphasis mine. So I'd say that we've now confirmed that it is named after where it is commonly found. If you want to thank me, you could do so by editing the H. pylori article to cite that ref for the claim that Marshall first detected it in the second sentence, and possibly later for a new sentence explaining the name :) SemanticMantis (talk) 17:08, 29 June 2015 (UTC)

Home-made air conditioner

The air-con projects I have seen so far are build based on ice (from the freezer) in some isolating box and blowing a fan on it.

Is there a home-made air-con project that would not work with the principle above? Something based on evaporating water could also work, couldn't it?--YX-1000A (talk) 17:01, 29 June 2015 (UTC)

Yes, evaporative cooling is our general article, the devices are commonly called swamp coolers in parts of the USA, though many names are used. These get a lot of use in greenhouses, where you might not mind exchanging some heat for humidity. I just recently saw a decent installation of one in an orchid house near Corpus_Christi,_Texas. Quite cooling indeed, even in a humid environment, despite reports that the maker of said cooler warned that it might not work well at that ambient heat and humidity. Might not be very suitable for in-home use in very humid climates though. Here's a homemade version I found on youtube [3]. SemanticMantis (talk) 17:21, 29 June 2015 (UTC)

An even simpler method is to drape a damp towel over a box fan (being sure to leave enough air flow to not overload the fan). You will need to rewet the towel often, though. You can toss it in the washing machine periodically with some bleach to avoid mildew. StuRat (talk) 17:51, 29 June 2015 (UTC)

Another way to make a homemade air conditioner would be to get a long hose (ideally thin-walled), connect to the faucet, loop the hose around the room, have it drain someplace safe, and turn the water on. This relies on underground water pipes supplying cooler water than the air temperature. Advantages are the simplicity and no electricity use. However, it is extremely wasteful of water, so would only make economic sense if you drain the water someplace you can use it anyway, like to irrigate a garden/crops, fill a bathtub (that would only take a few minutes, though), etc.

An alternate version could use a water pump and rain barrels (although the pump could be omitted if the rain barrels are elevated enough above the area you want to cool). Here it would only work early in the day, when the rain barrel water is still cool from night, but that water is free, so you don't have to worry about wasting it (although irrigating a garden or crops with it still makes sense). Both variations would likely only work to cool a small area, unless you are a farmer, and have need for massive amounts of water to irrigate your crops anyway, in which case the first method might cool the entire house (but a farmer is more likely pumping water out of a stream or underground reservoir, so there would be some increased electrical use to pump it through the house, too). StuRat (talk) 17:37, 29 June 2015 (UTC)

Swamp coolers are not very effective when evaporation is limited due to humidity (it just makes the room feel like a swamp by adding moisture to the air). The hose method is used in places where it is easy to cool water - such as Hawaii. Just run the hose extremely deep into the ocean to cool the water down and then loop it back up to the house. The actual system there is more complicated - but the principle is to send the house's heat into the ocean. Another method, not mentioned, is simply moving the air. If it is hotter at the top of a room than it is outside, automate a system of trapping the hot air at the ceiling and sending in slightly less warm air from outside - a rather poor version of a heat pump. Overall, none of those works as well as running coolant through a radiator and blowing air past it. Doing so also gives you the benefit of dehumidifying the air because condensation will collect on the radiator and drip down. 209.149.113.185 (talk) 17:47, 29 June 2015 (UTC)

And I suppose I should mention the method I actually use to cool my house. Put box fans (not those silly, tiny, underpowered twin "window fans" shown at the top of that article, but rather the large, single fan, shown below it) in windows, to blow hot air out and cool air in at night. Put all the fans blowing in at the lower floor and out on the upper floor to take advantage of the tendency of hot air to rise (or put fans pointing in on one side of the house and out on the other, for a single story home). Try to seal the area around each fan as well as possible to prevent local recirculation (air going the wrong way around the fan). I've cut a circular "mask" out of plastic sheeting for each fan, custom fit to each window opening, to do this. Don't leave any other windows open without fans. Can cool the house quickly when it is cool and dry at night and hot during the day. However, if it's humid out, say over 60°F dew point, the humidity getting inside makes it not practical. Also, you will have to make the house uncomfortably cold by morning to keep it cool all day, so wear a sweater to bed, and even then it's only good to keep the house maybe 10°F cooler than the outside temp. And if you leave the fans on too long in the morning you are paying to blow warm air into the house. Also, can't use this method when there's a risk of rain or bad fumes (like from cars in the driveway) that may be blown inside, or security issues with open windows. Still, with all these caveats, I can cool my house much faster than with A/C, under ideal conditions. Note that I mean the air is cooled quickly, but to cool the walls, floors, ceiling, furniture, etc., takes hours. If you don't cool those down, then the air temp quickly rebounds as soon as you turn the fans off.

One other caution is to always maintain positive pressure in the house, by having more fans blowing in than out. This means you turn the fans blowing in, on first, and off last. If you don't do this and create a negative pressure, it may suck exhaust (water heater, etc.) down chimneys, and you don't want that. StuRat (talk) 18:13, 29 June 2015 (UTC)

Number of bones and joints in human body

Ironically, Google search engine shows 360 joints according to non-reliable sources if you just type the following "number of joints in human body". However I'm really surprised why such very old question doesn't get interest of the scientific community to answer. I searched some other sites (like this), found that bones are about 206 in an adult human and about 250-350 joints. I assume that if a joint is linking two (or more bones unless there are two or more consecutive joints) and thus total number of joints should be always less than or equal total number of bones which should limit that of human body to 206 joint. Do you have an explanation?--Almuhammedi (talk) 21:18, 29 June 2015 (UTC)

A quick search on Google led me to Talk:Joint, where there are several links that try to explain this seeming contradiction in logic. Maybe it depends how one defines a "joint". ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:58, 29 June 2015 (UTC)

Please remember that some bones don't have precisely one or two joints; some bones have several suture-type joints, for example. Nyttend (talk) 12:16, 30 June 2015 (UTC)

Surprisingly, this is a question about Islam, not science. See [4] for example. --Dweller (talk) 12:22, 30 June 2015 (UTC)

Indeed the question is about Science, but a lot of Muslims are addicted to Quran and miracles, and so they filled web pages with such rubbish and even Google has been confused accordingly citing wrong information.--Almuhammedi (talk) 11:58, 6 July 2015 (UTC)