Wikipedia:Reference desk/Archives/Science/2012 March 26

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March 26

Flower Identification

Could someone tell me what this flower is called? They grow on a small tree. The burnt-looking edges of the petals are really interesting. Found in the southern U.S. Thanks so much!

72.218.72.80 (talk) 00:34, 26 March 2012 (UTC)happiness

Cornus florida --Digrpat (talk) 00:50, 26 March 2012 (UTC)

How much less does PARC's method of making fuel from seawater cost than the Navy's?

When we last checked in on our intrepid US Navy scientists, they claimed they could produce 41,000 gallons of fuel per day with 100 megawatts (page 28) which at typical electricity prices works out to less than a dollar per gallon. This process depends on extracting carbon from seawater which they have extensively detailed and scaled up for production. (Note that they claim their major stumbling block is resistance from electrode mineralization, which is probably one of the best understood problems in electrochemistry engineering -- you simply swap out cathodes periodically and treat the mineralized electrode in a solvent bath with a modest reverse current to dissolve the crusted calcification. I suspect this "difficulty" is a remnant of the security classification of this "Center for Safety and Survivability" project, but of course I have no proof.)

In any case, now, along comes the famous Palo Alto Research Center, not previously known for their work in alternative fuels, electrochemisty, or oceanic chemical engineering, and just last month publishes Eisaman, M.D. et al (2012) "CO₂ extraction from seawater using bipolar membrane electrodialysis" Energy & Environmental Science in which they state: "We efficiently extract CO₂ gas from the dissolved inorganic carbon of seawater using a new technique employing bipolar membrane electrodialysis [with] the ability to extract 59% of the total dissolved inorganic carbon from seawater as CO₂ gas with an electrochemical energy consumption of 242 kJ mol^-1(CO₂).... To put this number into context, simplistically considering the reaction of three moles of H₂ and one mole of CO₂ to form one mole of methanol (CH₃OH, LHV = 644 kJ mol^-1)^[31] with an overall energy storage efficiency of 20%, the CO₂ extraction energy of 242 kJ mol^-1(CO₂) represents only 7.5% of the required energy input."

My question is: How much less expensive, in terms of dollars per gallon, does this process make carbon neutral fuel from seawater, compared to the Navy's?

A second question: Does this process produce plastic feedstock carbon compounds which could be used to make structural plastic lumber (for carbon sequestration and reforestation) for less than the cost of wood?

Thank you. 71.212.241.67 (talk) 04:31, 26 March 2012 (UTC)

The 242 kJ/mol is only the electrochemical energy needed, it does not include the energy for pumping the water through the membranes, or the vacuum pump needed to extract the CO2 from solution. Makes comparing it with the Navy process impossible. As to the practical value, I notice they used DI water with added salt, and I'm guessing this means de-ionized water, so whether it would work in practice with real sea water remains to be seen. Using ACS reagent grade chemicals, lots of membranes, electrodes and catalysts will work, but once you're dealing with contaminations, most of those rapidly degrade. 84.197.178.75 (talk) 18:12, 26 March 2012 (UTC)

The text of the paper and much of the work that it cites explicitly involve scaling up processes which use real seawater. 70.59.24.75 (talk) 21:02, 28 March 2012 (UTC)

Comment - providing the full text of the paper, via the link above, is probably in violation of this paper's copyright. Here is the journal's landing-page: CO2 extraction from seawater using bipolar membrane electrodialysis, where you can access the full text if you have a subscription. Nimur (talk) 18:27, 26 March 2012 (UTC)

Wikipedia makes extensive resort to Fair Use, and we should recognize that others do also. In the old days before the Internet was big, every university library had a few photocopiers, often swamped by people with stacks of journals to photocopy, and every one of them was "violating copyright" the same way. There were some idiots like Nature constantly running ads about it, and there actually was some court precedent about it when people at a company had runners bringing them the photocopies - sometimes I wondered if it would serve everybody right if the policy was enforced all of a sudden, the universities closed, and people interested in science packed up shop and moved to Cuba to get any work done. Wnt (talk) 04:43, 30 March 2012 (UTC)

As for the question here... in general, the problem I have is, why is it cost-effective to extract CO2 from seawater when there is perfectly good carbon being burned in coal fired power plants and the CO2 released to cause the greenhouse problem?

The Navy slide presentation gives the formulae:

• H₂O -> H + O₂
• H + H₂O + CaHCO₃ -> HCO₃ + CaOH
• H₂CO₃ -> CO₂ + H₂O

Not sure why this is atomic hydrogen but I assume all entities here have to be neutral. Trying to balance this out:

• 2H₂O -> 4H + O₂
• 0.5H + 0.5H₂O + 1CaHCO₃ -> 1H₂CO₃ + 1CaOH
• H₂CO₃ -> CO₂ + H₂O

Unfortunately I can't make sense out of that second equation - either calcium is being swept under the rug, or extra oxygen has to be added, or hydrogen is released, or something. Allowing extra carbon to come into the equation is clearly not an option. But on consideration of the next equation they must mean H₂CO₃ to be released. Even so ... I still don't see what the added hydrogen is needed for, since it's a straight swap of bicarbonate for hydroxide ion. Hmmm.

Meteorite identification

I'm a bit puzzled about the identification of this meteorite as TinEye didn't help. The capture says it's 1581 in Germany, is it that in Thuringia or it's just the artwork from 1581? The Russian caption mentions the locality, something like "Niederraisen", whose correct German spelling I can't figure out. --37.31.49.254 (talk) 11:54, 26 March 2012 (UTC)

It is. "Нидеррайзен" seems to be an ad-hoc or old-fashioned cyrillisation of Niederreißen (normally written as Нидеррайсен), a town in Thuringia. The English article is very sparse, but according to the German Wikipedia:

Am 26. Juli 1581 fiel gegen 13 Uhr ein Meteorit in ein Gartengrundstück. Der Stein mit einem Gewicht von 39 Pfund wurde nach Dresden gebracht. Über seinen weiteren Verbleib ist nichts mehr bekannt.

which I believe is roughly:

On the 26th July 1581 at around 1 PM, a meteorite landed in a vegetable patch. The stone, which weighed 39 pounds, was taken to Dresden. Its whereabouts are now unknown.

Hope that helps. Smurrayinchester 13:33, 26 March 2012 (UTC)

African Hairless Dog

The African Hairless Dog is still alive?--Proki (talk) 12:16, 26 March 2012 (UTC)

I'm unsure how to take your question. There are still examples of the breed which are living. It's unknown whether the one that is pictured in the article is still alive. If you meant something else, please specify what it is you're asking. Dismas|^(talk) 13:01, 26 March 2012 (UTC)

The one pictured in the article is stuffed.--Shantavira|^{feed me} 13:33, 26 March 2012 (UTC)

Serves me right for not looking closer.  :( Dismas|^(talk) 16:07, 26 March 2012 (UTC)

Actually, both "external links" from that article say that there are no confirmed living members of this breed. I think it's safe to say that few if any purebred members of this breed exist. APL (talk) 01:57, 27 March 2012 (UTC)

This is a living animal of the breed: [1]. Stay in that it is a very rare breed. --Proki (talk) 13:26, 27 March 2012 (UTC)

Smiling Moon

Why are there no refenences to the smiling moon that has been clearly visible in the sky over the last few months as of 3/26/2012. There seems to be no news coverage of it as well. It would seem that there is something wrong or a change is occuring. Please explore this matter ! — Preceding unsigned comment added by 67.212.42.101 (talk) 15:36, 26 March 2012 (UTC)

Well, that's the first time I've heard the term smiling moon! A quick google for "smiling moon" reveals some images of a crescent moon (the "smile") with 2 bright stars above it (the "eyes"). It that the sort of thing you're talking about? Most likely the "stars" are Venus and Jupiter, currently both very prominent in the dusk sky, and close to the moon. Nothing to be worried about! Fgf10 (talk) 15:50, 26 March 2012 (UTC)

I don't know what it's doing in Loris right now but it is definitely not smiling in the UK. Could be an interesting case of pareidolia. ;) Richard Avery (talk) 15:56, 26 March 2012 (UTC)

The basic reason for the "smiling moon"

It's a well observed behaviour of the moon - the Hawaiians call it a wet moon (so called because it looks like a bowl of water, and tends to herald the wet season), and it can also apparently be a Cheshire moon (like the cat) or a West Virginia moon (a reference I don't understand). The article on the wet moon has a decent explanation of why this happens. It's something that happens in the winter, and the smiling effect will decrease as summer approaches. Smurrayinchester 09:33, 27 March 2012 (UTC)

on this point, someone said venus or another bright planet is visible at present from the northern hemisphere, much brighter than a star (and not twinkling). Is this true? Is there a site that lists planets visible at present? — Preceding unsigned comment added by 80.99.254.208 (talk) 19:00, 26 March 2012 (UTC)

Yes, that's true. Venus is visible, right now just right of the moon. A little closer to the horizon is Jupiter, and you can at the same time see Mars in the south-eastern sky, in the constellation of Leo. There are various sites that list planet positions, but the best tool currently available for free (works for both Windows and Linux) is Stellarium (computer program). Google Sky Map for Android is quite decent, too. --NorwegianBlue ^talk 19:32, 26 March 2012 (UTC)

While trying to more directly answer your question, I visited these sites:

• http://neave.com/planetarium/ -- interactive and nice, but hardly any labels for planet names and names of major stars, and I found no obvious way of enabling these globally. When doing a mouseover over a celestial object you get the info, however.
• Your Sky -- The first website I used for this purpose. Not very interactive, but still good. --NorwegianBlue ^talk 19:53, 26 March 2012 (UTC)

Jumping centipede ?

I occasionally get centipedes on my wall, here in Detroit, and they run like hell when I try to kill them. But this particular one seemed to have a new strategy, he jumped onto the dark carpet, effectively camouflaging himself as he ran away. He got away. Do I have the Einstein of centipedes here, or is this a known behavior ? StuRat (talk) 23:13, 26 March 2012 (UTC)

What makes you think it was intentional? If it only happened once, it could easily just be a coincidence. There are plenty of animals that do camouflage themselves, though, so it isn't impossible. --Tango (talk) 23:48, 26 March 2012 (UTC)

They seem to be rather good at holding onto walls, I've even seen them on the ceiling. So it seems unlikely one would just fall off a wall, especially right as I approached to squash it. StuRat (talk) 05:23, 27 March 2012 (UTC)

Natural selection needs variation to act on. gene pools that have survived up to this point have done this by being good at letting variations in individual traits emerge. Jumping seems to be a useful variation that that ought to be selected for in a proportion of centipedes that face being stepped on by human predators/ stuck in a hole / crushed by falling rock / etc. I have no idea how common this trait is among centipedes, but it seemed to work well for the one that escaped from you, so this trait is well developed it would appear. SkyMachine ⁽⁺⁺⁾ 05:19, 27 March 2012 (UTC)