Wikipedia:Reference desk/Archives/Science/2011 January 14

= January 14 =

Sail
What is the name of the sail that hangs under the bowsprit, as seen here? --  T H F S W  (T · C · E) 00:02, 14 January 2011 (UTC)
 * According to this lexicon it is called a spritsail, although our spritsail article doesn't give any indication of that. Looie496 (talk) 00:24, 14 January 2011 (UTC)
 * The bowsprit article, however, does mention that one or two "spritsails" could be hung from yards on the bowsprit. –Henning Makholm (talk) 00:47, 14 January 2011 (UTC)
 * I find that somewhat surprising, as a spritsail is normally a fore-and-aft sail. The rectangular sail under the bowsprit is called a Blinde (literally "blind one") in German, and German sailing terminology shares low German roots with English. Does this ring a bell? --Stephan Schulz (talk) 01:02, 14 January 2011 (UTC)
 * Our overly-thorough sailboat diagram doesn't show any sail projected below the bowsprit. (I have never seen anything there on any ship either, but I haven't spent much time on tall ships).  Our carrack article names six sails: "bowsprit, foresail, mizzen, spritsail, and two topsails" - so we can rule out a few of those.  Our spritsail article illustrates what I would call a gaff rig; so let's call the square forwardmost sail on Santa María the "bowsprit sail" until something more authoritative comes along.  Nimur (talk) 01:44, 14 January 2011 (UTC)
 * Here is another web source that also calls it a "spritsail": "An additional sail, the spritsail was bended to a yard under the bowsprit. The sail was called "blinda" in Germanic languages, which reflected the fact that the sail effectively prevented visibility forward." –Henning Makholm (talk) 02:21, 14 January 2011 (UTC)
 * And here and here, from published books and thus higher on the WP:RS scale. This source also seems to be a webification of an actual book. –Henning Makholm (talk) 02:32, 14 January 2011 (UTC)
 * One more web source, then I'll stop, promise. –Henning Makholm (talk) 02:37, 14 January 2011 (UTC)
 * New stub article Spritsail (square-rigged) created. –Henning Makholm (talk) 03:38, 14 January 2011 (UTC)

Positive beta decay
The articles on positron emission and such don't really explain this well. My understanding is that a proton absorbs a W+ boson and it then turns into a neutron while releasing a positron and an electron neutrino. Is this correct? ScienceApe (talk) 04:57, 14 January 2011 (UTC)
 * I would put it slightly different. The proton EMITS a W+ WHILE turning into a neutron AND THEN the w+ turns into a positron plus electron neutrino. Dauto (talk) 05:08, 14 January 2011 (UTC)
 * There's a diagram and formulas at W and Z bosons. –Henning Makholm (talk) 05:16, 14 January 2011 (UTC)
 * That's a diagram of a negative beta decay. Granted the diagram for a positive beta decay would be very similar to that one. Dauto (talk) 05:29, 14 January 2011 (UTC)
 * Oh, right. –Henning Makholm (talk) 06:18, 14 January 2011 (UTC)

Thanks, but a proton needs energy in order to turn into a neutron. Where does the energy come from? ScienceApe (talk) 18:18, 14 January 2011 (UTC)
 * It comes from nuclear binding energy. The neutron must come out of the interaction in a state within the nucleus that has lower energy than the one it occupied as a proton. Neutrons and protons obey the Pauli exclusion principle separately, so in a nucleus with a relative surplus of protons there can be unoccupied neutron states with lower energy than the highest occupied proton state.
 * The energy thus released is nowhere near the rest mass of a W+, but thanks to quantum tunnelling, the W+ is allowed to exist as a virtual particle for a short time until it decays into a positron and neutrino. The two leptons are much lighter than the W, so even if the W had negative kinetic energy there can be enough energy left over to produce a real positron and neutrino. –Henning Makholm (talk) 20:51, 14 January 2011 (UTC)

Kindly help me find some good used solar panels for the K-State Wesley
Even though I don't tithe regularly, I don't like to let God down by depriving His churches this way. While reflecting on this, I decided that a better, 21st-century way to tithe would be to give a gift that will keep on giving long after the initial offering.

Such a gift would be in the form of residential wind turbines or solar panels. An energy-generating wind-turbine of any form could be well out of my budget range (I'm looking for no more than a $400 investment) so I've decided to find our campus ministry center a solar panel to donate.

Froogle.com won't be too useful when I search for "used solar panel," so that's why I seek your suggestions. I prefer used for the cost savings, but I hope they're still quite useful despite no longer being new. I also hope for a substantial power output from the said panel. The more watts-per-dollar, the better.

I believe that when item donations to churches/ministry centers keep generating them money (or saving them costs), the donor would keep tithing to God even when not actively giving. Therefore, I would call this a form of "passive tithing," a term most of you have never heard of, but would be possible thanks to these environmentally-inclined power generators. —Preceding unsigned comment added by 70.179.178.5 (talk) 09:14, 14 January 2011 (UTC) --70.179.178.5 (talk) 09:14, 14 January 2011 (UTC)


 * Sorry to throw cold water on your idea, but $400 doesn't come remotely close. Just the inverter and grid hookup will cost you thousands (including installation). Almost no one sells used solar panels, so used are not much cheaper than new. And $400 in solar panels will get you maybe 150 to 300 watts (and remember practically you'll get 1/3 of that because of night), which is almost nothing for a large building, and that doesn't even include installation. On top of that solar panels have a payback period of around 5 to 15 years - meaning it will take that long for them to save $400. Ariel. (talk) 10:33, 14 January 2011 (UTC)


 * Um shouldn't you get a job before you worry about tithing ? Also have you considered donating a bidet? Considering how wonderful they are perhaps the church will find more members come because of the bidet? This would seem to be the greatest gift of all at least for most churches. From your POV you'll get converts both ways! Nil Einne (talk) 11:05, 14 January 2011 (UTC)


 * It would be feasible to set up a little solar demonstration project for $400 total. Harbor Freight presently offers a 45 watt solar panel kit on sale for $159.99. A number of hobbyists have YouTube videos showing what they have done with these kits: . It includes 3 solar panels totalling about a meter square, and a steel frame which shoulde be bolted to wood crosspieces as a base. It includes a battery charge controller which provides regulated outputs of various DC voltages and a digital voltage display. It includes two 20watt equivalent, 5 watt actual fluorescent lights. To function, it must be connected to a storage battery. For a storage battery you might choose a 12 volt deep cycle battery intended for use with a backup sump pump. The price will vary with the amp hours, but one for about $100 is designed to run a sump pump 6 hours. Battery acid is a few dollars extra. Some have used smaller UPS type batteries of just a few ampere hours. Harbor Freight suggests a 300 watt inverter to operate AC. The bigger the inverter, the quicker it will drain the battery. Small inverters are available which can connect to the grid and push power back into the AC mains. An installation this size could provide a few hours an evening of lighting for a small area, or could run AC equipment for a shorter period each day. It could also be used to charge rechargeable appliances. Edison (talk) 16:00, 14 January 2011 (UTC)
 * One experimenter on Youtube claimed that even the full moon's light could produce measurable current, though not sutticient to power anything. Edison (talk) 18:43, 14 January 2011 (UTC)
 * (after ec) Please stop with the irrelevant answers and direct insults to our questioners. If you don't know the answer, please don't bother to reply. If you feel a need to disrepect other's religious beliefs, please find one of the many not-Wikipedia forums available on the internet. Solar panels, even used ones are often available on Ebay or Craiglist and similar sites. Solar installation companies and suppliers sometimes sell used panels from refits and upgrades. Solar panels last a very long time time. For instance, several of the solar panels from the Carter White House project are still in use and have made the news recently. Solar panels are certainly available for less than $400 - the are just lower wattage models. For instance, shows $400 buys a panel in the 50 to 85 watt range. Panels with integrated micro-inverters are available which can be used with no wiring or installation at all. Plug it in and shove it in a window. Of course, they are more expensive and less efficient when used in this manner. This is not an impossible mission but is one of very long-term returns. See also Home Power magaizines' solar  guerillas.[ Perhaps organizing a group of like-minded individuals to finance a larger installation or convincing the facility to use a single panel in a prominent and symbolic location?  [[User:Rmhermen|Rmhermen]] (talk) 16:12, 14 January 2011 (UTC)
 * To whom were you responding? Are you OK? Edison (talk) 16:16, 14 January 2011 (UTC)
 * Not you, Edison. We were both writing at the same time. Rmhermen (talk) 16:20, 14 January 2011 (UTC)
 * Could you clarify precisely who you are replying to? I see there are some replies from CA3 which were removed and the indenting is very confusing here Nil Einne (talk) 17:06, 14 January 2011 (UTC)
 * To clarify, there is a discussion on the talk page about some extremely insulting comments that were removed. I've fixed the indenting so that responses to the original poster are all at the first level, as they should be.  Rmhermen's admonition against irrelevant responses and direct insults applies to remarks which are no longer present, not to anyone whose posts remain here.  Sorry for any confusion.   TenOfAllTrades(talk) 17:45, 14 January 2011 (UTC)

Hiroshima/Nagasaki and radiation
Do we have an article/s that deal/s with persisting levels of radiation in these cities? I couldn't find the information during a quick flick through some likely articles. --Dweller (talk) 10:43, 14 January 2011 (UTC)
 * A couple of weeks ago I ran across something, probably off-wiki here, that stated that neither city had much residual radiation even in the days immediately after the attacks because the explosions were airbursts and thus relatively clean. "Clean" in this context would mean that the fission products and unfissioned material fell elsewhere, and that the main radiation exposures to humans were neutron exposures from the moment of actual explosion. I can't remember where I saw it, though.  Acroterion  (talk)  13:35, 14 January 2011 (UTC)
 * We have answered earlier about Present day radiation levels at Hiroshima and Nagasaki. Cuddlyable3 (talk) 14:56, 14 January 2011 (UTC)

Birds and animals living along the Rhine River
I have searched and searched for information on birds and animals living along the Rhine River, to no avail. Can you help? —Preceding unsigned comment added by 87.156.247.172 (talk) 13:38, 14 January 2011 (UTC)


 * The Rhine: an eco-biography appears to mention the flora nad fauna of the Rhine, but it also refers to Robert Lauterborn, saying that by the time he died in 1952, he had published over 100 articles on Rhine Flora and Fauna - He might be a good person to search for. Searching for him on google scholar does turn up a number of articles but the almost all appear to be in German. Obviously though, being dead, he won't have published any articles recently - A you searching specifically for recently published information?
 * On a side note, he does look like a suitable candidate for an article. Darigan (talk) 14:53, 14 January 2011 (UTC)
 * additional source that may be of some use, pdf doc: Robert Lauterborn (1869—1952) and his Paulinella chromatophora Darigan (talk) 14:55, 14 January 2011 (UTC)

Biomass into Crude Oil
This is kind of off the wall, but: I heard a comedian state that he wanted to be cremated because he "didn't want to end up as someone's oil" at some point in the future. Now, the unlikeliness of that aside, it got me wondering: how much biomass from ancient life end up as a barrel of crude. Or more simply: How many "dinosaurs" (I know, I know...) are in one gallon of gasoline/petrol? Arakunem Talk 15:51, 14 January 2011 (UTC)


 * Perhaps a bit more technically, one might rephrase the question as "What are the origins of kerogen, and what fraction of that do large land animals represent?" While I suspect the answer is 'not much at all', I don't have a more quantitative result handy.  Our article on Biomass notes that most of the biomass on earth is on land, and that plants there outweigh animals by about a thousand to one.  If we assume a proportionate contribution to oil formation, then the animal contribution to a gallon of gas is less than a teaspoon.  The contribution of any single species to that teaspoon, meanwhile, is apt to be tinier still. TenOfAllTrades(talk) 17:06, 14 January 2011 (UTC)


 * Given the quotes around dinosaurs and the "(I know, I know...)", I think the questioner wasn't interested in actual dinosaurs but may have been looking for general efficiency numbers. That is, during the time when oil was forming, what proportion of total biomass was locked away as oil? Or, slightly differently, how much raw biomass would you need if you wanted to create a gallon of petroleum? (BTW, oil is generally thought to have formed from microscopic ocean life. Terrestrial biomass (plants) formed coal.) -- 174.21.250.227 (talk) 17:17, 14 January 2011 (UTC)


 * I was actually reading a bit on this the other day. The estimate was that about 1 part in 1000 of organic material was buried and stopped recycling through the carbon cycle.  So, 999 out of every 1000 plants/animals/algae are eaten or decay in a biologically useful way, and 1 is buried.  Of that 1 out of 1000, only about 1 out of 1000 convert to economically producible hydrocarbons.  Basically, 1 Carbon atom out of 1,000,000 is turned into oil or gas or other hydrocarbons.  The reference given in the text is Waples, D. W., 1981, Organic Geochemistry for Exploration Geologists, Burgess Publishing Co., Minneapolis, MN, 151 p., but I can't read it on Google books, so I'm not sure if he actually says those numbers or if the authors of the material I was looking at came up with that number from another source. Tobyc75 (talk) 19:35, 14 January 2011 (UTC)


 * Is that a current estimate, or a long-term average? I've seen it suggested that coal deposits from the Carboniferous reflect the absence of fungi. Whether that's correct or not, I would guess that these rates are not constant over geological time. Guettarda (talk) 20:27, 14 January 2011 (UTC)


 * Was it Ricky Gervais? Guettarda (talk) 20:28, 14 January 2011 (UTC)


 * And because this is fascinating so I had to find out for myself, at 1 in 10^6 atoms becoming useful crude, with crude density being about 0.8g/mL, a 100kg person will yield about 0.25mL of crude. There are 5mL in a teaspoon, so this guy's only contribution to future societies is 1/20 of a teaspoon - not even more than the "pinch of salt" in recipes. That said, perhaps cremation will result in a much better rate of transference of the body, as ashes, into future crude - anyone know? SamuelRiv (talk) 04:46, 16 January 2011 (UTC)
 * There shouldn't be much carbon left in ashes at all. It all goes up the smokestack. (So instead of oil, you can become part of someone's breakfast cereal in the next round of the carbon cycle). –Henning Makholm (talk) 05:33, 16 January 2011 (UTC)

Follow-up: What looks like peas?
I asked the question here when there were still leaves oon the trees. I never remember to ask anyone on the college campus where the trees may be located. Or even if it is someone else's land, they have professors who teach students to identify trees. But I can't remember to do it.

This time of year the fruit or whatever you want to call it is dark brown and just hanging there. The bark makes the trees look like the leg of a deceased person. Those are the only clues I can offer. Vchimpanzee ·  talk  ·  contributions  · 20:17, 14 January 2011 (UTC)


 * Ask at WT:PLANTS. Guettarda (talk) 20:23, 14 January 2011 (UTC)
 * Thanks, I guess. Vchimpanzee ·  talk  ·  contributions  · 20:47, 14 January 2011 (UTC)
 * My guess would have been the carob tree, but in the previous time you asked, there was mention that these were not in pods. Googlemeister (talk) 21:51, 14 January 2011 (UTC)


 * Are you sure they are not lime trees as previously discussed? If you do not have a camera then you could use a scanner to produce an image of the "peas" and leaves. 92.15.25.173 (talk) 22:29, 14 January 2011 (UTC)

Anticoagulant in donated blood
For keeping donated blood from clotting, anticoagulants are added to it. However, what happens during a blood transfusion? Does the receiving patient get some anti-anti-coagulant or doesn't it matter? Quest09 (talk) 23:15, 14 January 2011 (UTC)
 * The anticoagulant is normally citrate, although heparin is occationally used in special circumstances. Citrate works by binding calcium ions, which are necessary for the coagulation cascade. The patient will of course receive all the citrate that is present in the blood product. However, citrate is normally metabolised rapidly in the liver, and does not cause coagulation problems in the patient. A patient who receives many units of blood/platelets/plasma needs to be monitored for hypocalcemia, which is easily corrected by giving calcium intravenously. --NorwegianBluetalk 10:37, 15 January 2011 (UTC)