Wikipedia:Reference desk/Archives/Science/2013 March 8

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March 8

Radiative transport?

Does the "Radiative transport" linked in the Sievert integral article mean the same thing as "Radiative transfer"? Or is this "Radiative transport" referring to some physiological aspect of radioactivity? I can't tell from the references. Thank you. Praemonitus (talk) 00:21, 8 March 2013 (UTC)

The former. The integral pertains to a layered medium, with $\varphi =0$ normal to the layers, such that $x\sec \varphi$ is the distance along a line at angle $\varphi$ to the normal to a point x away in the normal direction. Then the exponential decay of radiation over distance (in the simple case) is invoked. I'm not sure what should be taken from the weighting by angle; there may be compensating terms involving solid angle subtended at each end of the line segment. I think "radiation transport" (as it says: note the first word) is a common synonym for "radiative transfer"; it might deserve a redirect. --Tardis (talk) 03:08, 8 March 2013 (UTC)

Thank you for the clarification, Tardis. Praemonitus (talk) 05:23, 9 March 2013 (UTC)

Mixing chemicals

Hello. Can you tell me what would complete the following reaction, which I added together into a beaker. I have noted the solution is both black, and very acidic.:

C3H6O + H20 + NaCl + HCL + C3H8O + KCL + BaCl2 + HNO3 + CoCl2 + K2Cr2O7 + K2CrO4 + H2SO4 + K4Fe(C2O4)4·2H2O → ?

Thanks, Albacore (talk) 03:07, 8 March 2013 (UTC)

It depends on the initial concentration of the hydrochloric and nitric acids, many of the reagents in that reaction aren't reagents at all, and may only at best act as catalysts. The final solution is black because of colloidal carbon. Plasmic Physics (talk) 03:41, 8 March 2013 (UTC)

Also, barium sulfate may crash out of the solution, and if the chromate/dichromate is concentrated enough, they may oxidize the isopropyl alcohol to acetone. Of course, if the sulfuric acid is concentrated enough, it will dehydrate all organic compounds in the mixture to carbon like Plasmic said -- but if the nitric acid is highly concentrated, then it might in turn oxidize the carbon to CO2 (which will bubble out of the solution because of its low solubility in acid)! So if I had to guess, I'd say your solution contains the following: H2O (solvent), C(s), C3H6O(aq), Na+(aq), Cl-(aq), H3O+(aq) (lots of), K+(aq), BaSO4(s), NO3-(aq), Co+2(aq), Cr2O7(aq), HSO4-(aq), CO2(g), and Fe+2(aq). 24.23.196.85 (talk) 06:43, 8 March 2013 (UTC)

Oh, I forgot the oxalic acid H2C2O4(aq) (which will be fully protonated because of the acidity). 24.23.196.85 (talk) 06:48, 8 March 2013 (UTC)

A biological question about myself

we cannot offer diagnosis or medical advice
The following discussion has been closed. Please do not modify it.
I once took an otc pill was for Common coldness (it was in 2011) and contained: Dexchlorpheniramine maleate Pseudoephedrine for an unkown reason, it maid my hand-skin very dry !!!, so much so, that after 5 days some of the skin on the middle of the upper hand (next 2 where the fingers start-out), and also, in some cushions of the hand, skin could be easily ripped off from this areas (and it wasn't painful). other Antihistamine drugs didn't do that 2 me (except 2 one which i think contains the same AH molecule mentioned above, but don't take my word for it). could you at least try 2 tell me about this very interesting mechanism? thanks 4 your time. Ben-Natan (talk) 05:50, 8 March 2013 (UTC) The drug is a common antihistamine decongestant combination. Your skin changes were either (1) an effect of the respiratory infection for which you took the drug-- several of them can cause late skin desquamation and peeling; (2) an allergic reaction to either component of the drug; or (3) due to something completely unrelated. Note that an allergic reaction to a drug is different than a "side effect"-- what you describe is not a recognized side effect of either drug. I suspect the first possibility is most likely. The only way I can think of for you to determine whether it was a drug effect would be to take it again for a few days: if it didnt happen again, it probably wasnt the drug. Note that this is speculation because you asked for it and not medical advice. alteripse (talk) 12:41, 8 March 2013 (UTC) This is a one-off trial with a sample size of one person and no double-blind control. Literally nothing can be deduced from it. Without other information, there is zero reason to assume that the effect on your skin had anything whatever to do with the medication - rather than some chance encounter with some chemical or biological agent over some several days before you skin condition popped up - or as a side effect of the disease that caused you to take the drug in the first place. To even credit the question as something worth answering, you'd first have to take a thousand people, give half of them the medication and the other half a placebo, count the number that have skin problems and see if the result is higher for those taking the medication than those that didn't. If that's a big enough difference, then it's a side effect and you can start to ask why it happens. But if not...then this is not a meaningful question. Since the manufacturers most certainly did some kind of a trial like this for all of the active ingredients, then if this were a reasonably common side-effect, it would be printed on the label someplace. So check the label - and if it describes this symptom, then we can probably find the cause somehow. If not - then it was almost certainly something else that caused your skin issues. SteveBaker (talk) 14:20, 8 March 2013 (UTC) Hi. For the first answerer, anytime i take the drug, the exact thing happen, i took it again before and after the aforementioned time. thanks. Ben-Natan (talk) 17:16, 8 March 2013 (UTC)

the human singing voice - effects of age

Until age 50, I had a soprano voice and could sing a high A without difficulty. In the 15 years since, it has dropped an octave. I now sing (croak) lower than my husband does. I am aware that voices change over time and that women's voice generally get lower. What physical changes account for this please? And does it matter? There have been no illnesses which might explain it and my speaking voice has not much changed. Thank you. — Preceding unsigned comment added by 109.12.62.161 (talk) 07:59, 8 March 2013 (UTC)

One of the illnesses that affect voice, and that affects many females over the age of 50, is hypothyroidism. I presume you've ruled that out. --TammyMoet (talk) 10:25, 8 March 2013 (UTC)

Firstly, we're not allowed to diagnose medical issues here on the Wikipedia reference desk - that's a huge "No-no" for use! So our advice has to be limited to "Go see a doctor"...and something like this does have the potential to be indicative of medical issues that you might not otherwise have noticed (see Vocal cord dysfunction for a range of alarming possibilities), so that's especially good advice in this case.

Our vocal cord article suggests that menopause can specifically change a woman's singing voice, and since this evidently happened in your early 50's (which is plausibly the age when menopause happened for you) the timing is right for that to be the cause here.

If all else fails...there is always helium! :-)

SteveBaker (talk) 14:37, 8 March 2013 (UTC)

And menopause causes a lowering in the voice frequency due to changing hormone levels (a higher testosterone to estrogen ratio, which also can cause facial hair). I wonder if anyone has studied if hormone replacement therapy reduces or reverses this effect ? StuRat (talk) 16:14, 8 March 2013 (UTC)

Does the concept of a "quantum speed" make any sense?

I am currently taking a Quantum Chemistry class at university and to test our knowledge on quantum mechanics, the professor just posted a rather interesting question. The question is:

"Does the concept of a 'quantum speed' make any sense?"

I thought this question in two ways:

1) Speed as a continuous variable is not quantizable. This means a "quantum of speed" doesn't exist, and therefore the concept of a "quantum speed" does not make any sense.

2) Since speed is the magnitude of velocity and velocity is the time derivative of position, the speed of a particle trapped in a box (say, a 1-D infinite square well potential) is represented by || d/dt [xΨ(x,t)] ||. Taking the position operator on the wave function yields a position with an imaginary part, and taking the magnitude of the time derivative of a complex position should be able to yield a real solution. Would the real solution represent the "quantum speed"

Am I at all on the right track with these two approaches? Hope to hear you guys' insights! — Preceding unsigned comment added by 169.232.187.44 (talk) 08:28, 8 March 2013 (UTC)

What evidence do you have to support your theory that "speed as a continuous variable is not quantizable"? It might be true, but is it established as a fact? See Planck length and Chronon. Also see [ http://arxiv.org/pdf/quant-ph/0004086.pdf ]. --Guy Macon (talk) 10:19, 8 March 2013 (UTC)

The Planck length is just a distance at which quantum gravitational effects should become large. There's no particular reason to think that distances are quantized in units of the Planck length. Anyway, there's no Planck speed—or rather the Planck speed is c, which isn't particularly helpful in this context. -- BenRG (talk) 23:09, 8 March 2013 (UTC)

Perhaps an overly simple approach: aren't speed and temperature essentially the same thing, on a quantum scale? Isn't temperature quantized? --Mr.98 (talk) 12:50, 8 March 2013 (UTC)

Sorry for the digression, but no, absolutely not. Speed and temperature are not remotely the same thing. In fact temperature has nothing directly to do with kinetic energy. Temperature is a measurement of the relationship between entropy and internal energy. This is the statistical mechanics approach to temperature, and it is far more fundamental than the kinetic approach. Temperature can even be negative, that is, below absolute zero, which is obviously not possible for speed or kinetic energy. --Trovatore (talk) 17:13, 8 March 2013 (UTC)

Define a linear speed operator S by defining it on the functions exp(i k x) (which form a complete set), as

S exp(i k x) = hbar |k|/m exp(i k x)

Then S is defined for all states. You then need to check to see if S is a Hermitian operator. Count Iblis (talk) 15:51, 8 March 2013 (UTC)

In physics, I believe there are some massless particles which can only go the speed of light, while particles with rest mass can go speeds below, or, theoretically, above the speed of light, but not precisely that speed, as getting there would require infinite energy. A complicating factor is that the speed of light itself varies, depending on the medium. StuRat (talk) 16:04, 8 March 2013 (UTC)

If you're implying that particles can't travel faster than the speed of light in a medium, that's absolutely wrong. They can and do break the "light barrier" in water all the time, and the result is Cerenkov radiation. --140.180.243.114 (talk) 18:53, 8 March 2013 (UTC)

(Mostly responding to StuRat) The speed of light in a medium is just the speed of light in a medium and has nothing intrinsically to do with the speed of anything else. The universal constant c has nothing intrinsically to do with light, even though it's often called "the speed of light in vacuum" or even just "the speed of light". So your second sentence isn't a complicating factor in any physical sense. It's just a pun on the phrase "the speed of light". -- BenRG (talk) 23:09, 8 March 2013 (UTC)

To the OP: maybe I'm missing something here, but why can't you apply the momentum operator to the wavefunction, calculate the inner product of the result and the wavefunction, and integrate over all space? That would give you the expectation value of momentum. Divide that by mass and you'll get the classical analogue of velocity for a wavefunction. --140.180.243.114 (talk) 18:53, 8 March 2013 (UTC)

I wonder if this question had some specific context—i.e. there was something in the lectures or readings recently that looked like it was about "quantum speed", and the question is whether that's accurate or misleading. Without context it's hard to know what to say. Speed is an observable in quantum mechanics, as other people have already said. It's not quantized in general (though it can be in particular cases like the particle in a box), but not being quantized doesn't mean it's not quantum—"quantum X" and "quantized X" generally mean different things. -- BenRG (talk) 23:09, 8 March 2013 (UTC)

There isn't a really specific context that I can provide I'm afraid. We just wrapped up 3D particle-in-a-box and moved onto the harmonic oscillator approximation. The professor is pretty big on the interpretation of Quantum Mechanics though. I suppose the context for a "quantum speed" comes frmo the latest Verizon adverts where they allow the users to upgrade to a faster internet speed called "quantum." I think that's where he based the problem off of. In regards to 140.180.243.114, taking the momentum operator and then dividing it by the mass does seem to be a much quicker way to determining the velocity! — Preceding unsigned comment added by 169.232.187.164 (talk) 00:22, 9 March 2013 (UTC)

See also group velocity and phase velocity ? Jheald (talk) 10:11, 11 March 2013 (UTC)

Something about coelomates

In here (page 95), the classification chart of animals into different phyla is given. I'm having trouble understanding how coelomates are further divided. Can anybody help? Thank you. --Yashowardhani (talk) 09:30, 8 March 2013 (UTC)

The chart on that page clearly shows that coelomates are divided into Annelida, Mollusca and Arthropoda on one branch and Echinodermata and Chordata on the other. Wikipedia uses a 'superphylum' notation to name those two branches - so the Echiondermata and Chordata are both "Deuterostomes" (with a couple of other phyla tossed in that your chart doesn't mention) and the Annelida and Mollusca are all in the super-phylum "Lophotrochozoa". Wikipedia's chosen classification places the arthropoda in the "Ecdysozoa" super-phylum.

The trouble with these classifications is that they are changing rapidly as we discover more about the animals involved - and the entire structure of the tree is a matter of heavy debate with some biologists preferring a DNA-based approach, others an evolutionary approach - and with both laboring under some horrific mis-classifications made by observation of body structure alone dating back to Victorian times. Your book looks like it was probably published about 8 years ago...and things are changing faster than that!

SteveBaker (talk) 15:04, 8 March 2013 (UTC)

Some of the clades you mention, are fairly certain and stable such as the crown deuterostomes and the ecdysozoans. The big problem is the protostome/deuterostome dichotomy has turned out to be as flawed as the dicot/monocot dichotomy, with protostomy and dicotyledony turning out to be non-diagnostic symplesiomorphies. The linked information Yashowardhani provided would have been considered simplistic and out of date decades ago--it's basically suitable merely as an introduction to the fact that such concepts exist, as might be okay for non-science majors. There are plenty of popular books like Assembling the Tree of Life that are slightly more updated and at least bring up the issues that are at question. (Even that will be outdated, however--the field is in a huge flux, see Afrotheria for an unexpected recent yet now undoubted grouping.) μηδείς (talk) 01:25, 9 March 2013 (UTC)

The solubility of francium hydroxide: is it OR?

In Chinese article of francium hydroxide it is claimed that francium hydroxide is soluble in water along with this source:Maddock, A. G. (1951). "Radioactivity of the heavy elements". Q. Rev., Chem. Soc. 3 (3): 270–314. doi:10.1039/QR9510500270.. In English article of francium there is a similar claim using the same source says"Nearly all francium salts are water-soluble." But in the DOI page all I can say is an abstract of the research focusing mainly on the actinium series. So does this article actually describe the solubility of francium salts?

The article says "nearly all francium salts are soluble". That's it; no further details are given. It doesn't say water-soluble, though this is implied by the context. Chris (talk) 15:29, 8 March 2013 (UTC)

After all, the article might mean "soluble in molten tungsten"... :) --Guy Macon (talk) 17:05, 8 March 2013 (UTC)

What??? The wikipedia article did say water-soluble. You mean the doi article?--Inspector (talk) 23:57, 8 March 2013 (UTC)

Cinnamon Wattle

Hi!

How has the plant Cinnamon Wattle got its scientific name Acacia leprosa? Does it have something to do with leprosy? --213.214.155.24 (talk) 12:13, 8 March 2013 (UTC)

The word indeed derives from the original Latin word for leprosy (as of course does the English word itself), and in biological nomenclature is sometimes used to indicate a spotted or blotched appearance (as a sufferer of leprosy might have). Although it's not obvious in the pictures in our article on the Cinnamon Wattle, it looks as if the 'leaves' do have a slightly mottled appearance due to their texture. {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 14:42, 8 March 2013 (UTC)

This says: "Acacia; from Greek acis, a thorn. leprosa; having a whitish, mealy or scaly surface, presumably referring to the phylodes.". And according to leprosy: "The word leprosy comes from ancient Greek Λέπρα [léprā], "a disease that makes the skin scaly"". So the name basically refers to the scaly nature of the plant - and both "leprosa" and "leprosy" come from a common base term for scaliness. The plant itself has nothing whatever to do with leprosy. SteveBaker (talk) 14:45, 8 March 2013 (UTC)

Drat, I misread the title, and now I'm hungry for cinnamon waffles. StuRat (talk) 16:10, 8 March 2013 (UTC)

This here's the wattle, the emblem of our land,
you can stick it in a bottle, or hold it in your hand

— Monty Python

Amen. -- Jack of Oz ^[Talk] 04:27, 9 March 2013 (UTC)

specilization of the cell wall of epethilia

please i want it very soon

specilization of the cell wall of epethilia — Preceding unsigned comment added by 41.37.24.186 (talk) 16:07, 8 March 2013 (UTC)

See Epithelium, but "the epithelia" includes every type of tissue in the body, apart from muscles, nerves, and tendons. Without knowing the specific type of epithelium you need information about, it's not really possible to answer the question. Tevildo (talk) 18:07, 8 March 2013 (UTC)

Why azane, not nitrane?

All the examples listed at Substitutive nomenclature are constructed as main part of element name + "ane": borane, oxidane, phosphane. So why is azane not called "nitrane"? — Sebastian 16:44, 8 March 2013 (UTC)

It's named after azote which is an alternate name for nitrogen which has now fallen out of use. Dauto (talk) 18:58, 8 March 2013 (UTC)

Cool, thanks! BTW, German "Stickstoff" expresses the same idea, meaning "suffocating substance". — Sebastian 19:33, 8 March 2013 (UTC)

There's also Guns 'n' Roses copyright. μηδείς (talk) 01:13, 9 March 2013 (UTC)

Which they stole from Roy Acuff. 24.23.196.85 (talk) 03:37, 9 March 2013 (UTC)

Weird chemistry dream: The scent of a proton

I had an odd dream last night in which I was back in chemistry class. The teacher had a device which could strip the electron from atoms of hydrogen, leaving positively charged protons, which we sniffed via a tube stuck up the nose. They had an unpleasant acrid smell. Now in reality, would such a gas of low energy low density hydrogen atom stripped of electrons have a smell? I know that normal hydrogen is odorless. This is quite distinct from proton beam therapy. The Proton article in the section "Interaction of free protons with ordinary matter" says that such protons might combine with another atom or molecule to make "Bronsted acids," which makes the "acrid" scent in the dream plausible. Is such an experiment possible (however inadvisable)? Edison (talk) 17:56, 8 March 2013 (UTC)

It must have been an awesome dream! 140.254.121.60 (talk) 19:30, 8 March 2013 (UTC)

Maybe you were smelling ozone. The protons can also be called ionized hydrogen, and ions are generated during lighting storms which also makes ozone, which you can smell. Ariel. (talk) 20:18, 8 March 2013 (UTC)

Acrid: "Smells like Akron". :-) StuRat (talk) 22:51, 8 March 2013 (UTC)

Didn't you mean this Akron? 24.23.196.85 (talk) 03:40, 9 March 2013 (UTC)

Nope, Akron, Ohio, with that lovely rubber volcanization scent. StuRat (talk) 04:20, 9 March 2013 (UTC)

To be smellable, a substance must be volatile and soluble. (Volatile to get to your nose, soluble to penetrate the aqueous and lipid layers that surround the olfactory nerve cells.) I'm guessing that by the time a proton reaches your olfactory receptors, it's hydrogen, though as you point out other substances might be possible. - Nunh-huh 03:48, 9 March 2013 (UTC)

If a number of low energy protons were introduced to the olfactory area of the nose, they might steal an electron and become odorless hydrogen as you suggest. They might also latch onto another atom or molecule and share its electrons. The stray low energy proton would likely not combine with the nucleus of another atom, increasing its atomic number. Most air molecules would be nitrogen, followed by oxygen. What compound would nitrogen or oxygen plus a proton be? (For me, a chemistry or physics dream is interesting and thought provoking, while a math dream is literally a nightmare). Edison (talk) 03:20, 10 March 2013 (UTC)

A protonated oxygen molecule O₂H⁺ is called the hydroperoxyl ion.[1][2][3] The hydroperoxyl anion is O₂H^- the opposite charge. (but this may also just be called the hydroperoxyl ion too, casuing confusion) N₂H⁺ is rather boringly called protonated nitrogen.[4][5] The links I provided also list some reactions. There is also a protonated nitrogen dimer: N₂H⁺N₂ with two nitrogen molecules bridged by a proton.[6] There looks to be just enough material to justify articles. Graeme Bartlett (talk) 04:21, 10 March 2013 (UTC)

Thanks much. Edison (talk) 20:32, 10 March 2013 (UTC)

Actually, protonated oxygen is called dioxidanylium, and deprotonated hydrogen peroxide is called hydroperoxide, or dioxidanide. Plasmic Physics (talk) 06:10, 11 March 2013 (UTC)

Another name for dioxidanylium is hydroperoxonium. Hydroperoxyl is not an ion, it is the HO₂^• radical. Plasmic Physics (talk) 06:15, 11 March 2013 (UTC)

I'm thinking that you can't spray air full of protons without a counterion. A simple example would be H+ and Cl- ions. Of course these would be in equilibrium with HCl gas, which upon reaching moist nasal membranes will largely dissociate, and by the time the H+ affects an olfactory receptor, the Cl- is surely long gone. Since you have Cl- ions in your nose, i.e. sodium chloride, the very small amount of HCl gas you can smell without your olfactory epithelium falling out in clumps shouldn't have much of a smell. So HCl has a recognizable "sharp" smell, which should be roughly equivalent to the smell of a proton. Of course, you can argue that this isn't the "real" smell, since it probably reacts with something to create whatever scent you perceive, just as the smell of iron isn't its "real" smell, but that seems like excessive sophistry. Wnt (talk) 15:55, 12 March 2013 (UTC)

caffeine ==> adenosine receptors

Is caffeine a competitive agonist for ATP on the adenosine receptors? ATP stands for adenosine triphosphate, and it is used by cells as an energy source. Similarly, caffeine somehow gives you energy. Is it possible that they work the same way? 140.254.121.60 (talk) 19:27, 8 March 2013 (UTC)

The chemical that activates adenosine receptors is adenosine, not adenosine triphosphate. I am unaware of any evidence that ATP acts as an agonist at adenosine receptors. So I believe the answer to all these questions is no. You can look at our article on caffeine for more information. Looie496 (talk) 23:23, 8 March 2013 (UTC)

Adding water causes liquid soap to gel

We decant liquid dish soap from a large commercial bottle into a pump-action dispenser beside the kitchen sink. Recently in rinsing out the liquid remaining in the bottle by adding water, I found the resulting diluted soap lathered up well on the sponge and was then easier to rinse off the dish being washed. However, when I added water to the dish soap in the dispenser (about 1:3 ratio), I was dismayed to discover the lower part in the dispenser turned into a gel that resists dilution with water. What's going on here? -- Deborahjay (talk) 19:49, 8 March 2013 (UTC)

If you put the dispenser in warm water for a while, does the gel dissolve? --Guy Macon (talk) 20:00, 8 March 2013 (UTC)

I can't try that without recreating the original problem - I poured the entire contents of the dispenser into a large bowl and combined it with my fingers, then added much more water so it's highly diluted now. -- Deborahjay (talk) 20:23, 8 March 2013 (UTC)

I think what Guy is getting at is that the water temperature might make a big difference, with the water mixing much better if hot. Was the water a uniform temperature in both cases ? The other big difference might be the surface area. Presumable, on the plate, there was much more surface area available for mixing than in the dispenser. Next time, you might want to just add a little hot water to the dispenser, mix that in, then add a bit more, until it's all mixed. StuRat (talk) 22:48, 8 March 2013 (UTC)