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August 22

MO diagrams and term symbols

Regarding multiplicity, does the orbital momentum of unpaired electrons in non-degenerate orbitals cancel? For instance, in the hypothetical d⁸ excited complex, does the orbital momentum of the lone electron in the e_g orbital cancel that of the electron in the t_2g (is it a singlet or a triplet)?

   ↓

↑↓  ↑↓  ↑

Plasmic Physics (talk) 12:12, 22 August 2014 (UTC)

Multiplicity (chemistry) is solely about the number of unpaired electrons, not about their energy levels. The change (or lack of change) in total spin is one of the selection rules for electronic transitions. See Fluorescence#Physical principles for more discussion. DMacks (talk) 20:15, 22 August 2014 (UTC)

So, singlet then? Plasmic Physics (talk) 21:17, 22 August 2014 (UTC)

It's analogous to the example given in Intersystem crossing, yes. DMacks (talk) 03:03, 24 August 2014 (UTC)

Ho do I find the term symbol for a triatomic molecular MO diagram? Plasmic Physics (talk) 22:36, 23 August 2014 (UTC)

Molecular term symbol is the main article on the topic. It's horribly over-specific for a single simple type of molecule. Term symbol, although it's focused on single atoms, does talk through the basic analysis that's relevant in all cases (which orbitals to consider, what symmetry terms, etc.). DMacks (talk) 03:53, 24 August 2014 (UTC)

Thanks, I had a look at it. I don't understand it though. What makes a particular electron configuration symmetric or not. For instance, why is...

σ_s-p  ↑    ↑  

σ_s-p     ↑↓

n_s        ↑↓

...antisymmetric, whereas...

σ_s-p  ↑↓      

σ_s-p     ↑↓

n_s        ↑↓

... is symmetric (both states have C_2v symmetry)? Plasmic Physics (talk) 02:55, 25 August 2014 (UTC)

Solid state flight

Is it possible to propel a vehicle that flies in normal Earth atmosphere by some means that does not involve macroscopically moving parts?

• There is a very crude device the Crookes radiometer that does so weakly in a thin atmosphere, but I am thinking there ought to be some way to greatly improve its power. I understand you can't have a Maxwell's demon, but could you have a flat sheet of metal that somehow acts on air molecules that bump up against it so that those moving straight out bounce elastically, those that bounce to the left are greatly accelerated, and those that bounce to the right lose most of their energy, using only a catalytic amount of energy equivalent to not much more than those air molecules will generate when they eventually smack into others and reach equilibrium?

• How about an electrostatic system that charges tiny regions of air along a flat plate, then pushes on them with carefully patterned charge on the plate that responds adaptively to the measured external charge and pressure patterns?

• Or a gel that holds large amounts of dissolved air, releasing it on one side and absorbing it on the other to provide lift?

Etcetera. Could anything like this work? (But please let's exclude space-based solutions like photon drives, magnetic sails, etc., and any ordinary sort of hot air balloon) Wnt (talk) 12:41, 22 August 2014 (UTC)

Ramjets and solid fuel rockets have no moving parts - at least, on paper. In practice, real aircraft and rockets have electric pumps, hydraulic valves, starter devices, control surfaces and all sorts of peripheral moving parts. Nimur (talk) 14:15, 22 August 2014 (UTC)

Those without an irrational aversion to nuclear-powered aircraft may wish to consider nuclear ramjets such as Project Pluto. -- ToE 14:31, 22 August 2014 (UTC)

That prototype looks suspiciously like the rocket used in Flesh Gordon. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:30, 22 August 2014 (UTC)

Well, you need an upward force to counteract gravity...so what exerts a force?

• Bouyancy - so you have to displace the air with something lighter - which basically means balloons. Hot air, hydrogen, helium, methane...a vacuum (which is tougher than you'd think!).
• Action/Reaction - Newton's third law lets us push something downwards and have our aircraft go upwards as a result. The 'something' can be the air - or something that's ejected from the aircraft itself.
  • If it's the air itself, then you're thinking about jets and wings. But to use a wing, you need forward speed - which means either needing a rotor (like a helicopter or a hovercraft) - which fails the "no moving parts" rule - or something that uses a wing, needing a horizontal thrust instead. Generating horizontal thrust without moving parts is more or less the same problem as generating it vertically...although a glider operates without an onboard power source. Jets are definitely possible. RamJets...or pulse jets...or scramjets. The only moving parts are the fuel itself.
  • If it's something carried aboard the aircraft, then you have a rocket - or something very like one (eg that crazy spacecraft that drops atom bombs behind itself and then explodes them!) Firework rockets have no moving parts...so that could work...so do water rockets and such like. Of course if you count movement of the fuel as a "moving part" - then rockets are out of the question.
  • You could imagine an aircraft with a massive laser beam aiming downwards that would gain lift by photon pressure! (Well, you could *imagine* it...I don't think you could actually make it work!)
• Electric/magnetic forces - So we can think of a linear-induction motor powering a levitating train. Those can certainly be built with no moving parts. Trouble is that the magnetic force decreases as the square of the distance - so flying more than a few inches above the ground will be difficult!
• Forces exerted by something fired up from the ground, rather than down from the aircraft. So you could imagine a ground vehicle or some kind of a track or chamber which is generating an enormous column of upward moving air on which the craft balances. Those "indoor sky-diving" facilities use an enormous fan to blow air upwards and turn people into unpowered "aircraft"...if you're prepared to not count the thing that remains on the ground as a part of the aircraft - then there are all manner of ways to think of doing this. In a sense, a long distance glider that uses thermals and slope lift to get where it's going is using power generated elsewhere to do the work. You could imagine a large array of cannons on the ground, firing heavy weights upwards to impact the underside of a heavily armored plate that could be kept in the air that way. Basically, any mass, propelled upwards from the ground, could support the craft...if you allow the moving parts on the ground-based component to not count in the "no moving parts" rule.

I'm sure there are other possibilities.

SteveBaker (talk) 15:55, 22 August 2014 (UTC)

Ionocraft Jim.henderson (talk) 16:06, 22 August 2014 (UTC)

This is the general idea I was picturing: airflow would presumably be right to left. No idea if this could work.

The ionocraft is indeed an interesting lead! [1] I was reaching toward something similar in the second point above, but what surprises me about the hobbyist ionocrafts is that they rely on having single, fixed positive and negative electrodes. I would think that you could pattern the charge on a flight surface so that you would first use a very strong positive and negative voltage and intentional discharge to create little puffs of positive and negative air along its length, then continuously charge ever-changing strips of the surface to be intensely negative just behind the positive puff and vice versa so that they would always be pulling the surface forward relative to the puffs in the air, but without an actual discharge that would cancel the puff out. Wnt (talk) 17:10, 22 August 2014 (UTC)

If you're willing to put in a very large amount of energy, you can do nearly anything! The trick is to make this technology competitive with the costs, safety, and reliability, that can be delivered by more conventional propulsion schemes. Nimur (talk) 17:26, 22 August 2014 (UTC)

Well, the ionocraft article claims the method is very efficient, but doesn't scale. I don't know what would happen if it could scale, and I'm not sure this would really be a way to get there, but I feel as if there ought to be a way... Wnt (talk) 17:52, 22 August 2014 (UTC)

So far all the discussion has been on moving parts involved in lift or thrust or control surfaces. Note that there are many moving parts on aircraft unrelated to these. Wheels and landing gear is one category. Those could be replaced with fixed pontoons, if water landing is an option, or fixed skis, if snow landing is. You could possible land on skis on land, if it was prepared properly, such as spreading snow on it or a suitable substitute. However, I'd guess you need shock absorbers (with moving parts) to go with either skis or pontoons. For small enough unmanned planes, you can also catch them in a net.

If people are to be on the plane, then you need doors, unless the plane flies slow enough and low enough that the wind, noise, and low air pressure and temp aren't a problem. And rigid seats would be painful, but any soft surfaces will move a bit as you sit on them. Seat belts have moving parts, too, as do bathrooms and climate control systems. And, while you could use all touch screens for pilot controls, I doubt if those are as reliable as moving knobs, dials, buttons, etc.

Aside from aircraft, there's also projectiles fired from electromagnetic cannons. And there was an experiment where a metal object was spun up, then launched vertically using powerful ground lasers to push it upward. StuRat (talk) 21:59, 22 August 2014 (UTC)

Hmmm, the "rules" may be a distraction, but to be clear, subtle shifts in control surfaces are acceptable, special features on takeoff and landing are acceptable, ramjet fuel pumps are at best borderline, not firing things at the plane. The image I started with was a parallel-reality dream; I was in a bar with a fellow who was ticked off at a football referee so he tossed something called an "immerfliegende Bar-Dart", I think, which looked up navigational info for the name spoken, navigated its way out the window and a few blocks to the stadium, and proceeded to hone in on the ref's rump. :) Wnt (talk) 05:00, 23 August 2014 (UTC)

It wouldn't necessarily be static but I always wondered if Langmuir probes in a magnetized plasma could be biased electrically to generate a mechanical force. The concept of neutral current when the mass of electrons and ions is orders of magnitude differences seems like it could be exploited. Not sure what non-moving parts you want but any type of wing is motion of air over a asymmetric solid. Another thing that might be more "solid state" would be a wing with different temperatures driven by thermocouple principles. Basically a glider that creates it's own thermals using thermoelectric/thermocouple/heatpipe principles. Not sure on how difficult or practical. . --DHeyward (talk) 03:44, 25 August 2014 (UTC)

The glider would seem to spend a lot of energy making thermals it would immediately leave, so I'm not so sure. I can think of a few other variations: alternately heat a balloon and allow it to cool and extract some forward momentum with a properly set wing; or set up a little chimney ("electric ramjet?") and let the hot air push forward the vehicle by reaction. But they seem awfully inefficient because they allow the energy to be lost straight to heat, then try to salvage back part of it by some inefficient power generation process. Really, we'd want the stored energy to go directly to some sort of mechanical work on the air, just not on a macroscopic scale.

The Langmuir probe, well, I won't claim to understand it fully, and in any case, I'm looking for something in air. But the principles involved (Debye sheath / Bohm sheath?) might be relevant to the idea above. I can think of one case where I think most of us have felt electric charge give rise to wind: a Van de Graaf generator. Because that has a moving belt inside I was never totally sure the small air motions were due to the charge, but I would think so, since you have ions fleeing the central charge. Now the Van de Graaf is round and pushes wind all directions, and the ions get out of the area on the shortest possible route, so I'd think a different design would be more efficient, and the ionoflyer is proof of that much. But the other interesting thing about the Van de Graaf generators is that they can produce little "ball lightnings" which somehow, by magnetic effects I suppose, manage to take up macroscopic amounts of air. I'm thinking the problem with just propelling ions back along the wing is that if they merely move through the other air, without hitting it much, then they cannot deliver much thrust. You want to somehow "gum up" the air and make it have some decent reaction mass, and I wonder if some sheath, ball lightning, or other magnetically based mechanism could do that. I'll add (without any confidence) that there are claims that "Haunebu" had Van de Graaf generators aboard; usually those claims go on to follow a whole long track of crazy, but thinking about it from this perspective I have to wonder if there could be some misunderstood bit of truth in there somewhere. Wnt (talk) 15:48, 25 August 2014 (UTC)

Valveless ramjets are the clear winner there though. Your objection to a moving-parts fuel pump is easily countered by propelling them from a pressurized gas cylinder or a gravity-fed liquid fuel tank. Check out this (no-moving-parts) ramjet powering a go kart at alarming speeds: https://www.youtube.com/watch?v=5U-grFuXZ9U - all you need is a gas cylinder and an appropriately shaped U-shaped tube.

SteveBaker (talk) 15:37, 26 August 2014 (UTC)

That's a valveless pulse jet, apparently; I wouldn't expect a ramjet to take off from a standing start. I'll grant it has no moving parts, though that noisy monstrosity doesn't have the look and feel of what I'd be hoping for. Wnt (talk) 18:38, 26 August 2014 (UTC)

Using brute force n' ignorance, you might use a stationary, ground-based laser to heat a rocket engine with a cryogenic or liquid propellant - reflect the laser 90 degrees up under the rocket engine... the requirement not to have any macroscopic moving parts could be met simply by making the rocket motor such that the liquid reaction mass would flow by force of gravity down into the rocket nozzle/expansion chamber when a solid valve opened by shape memory effect (say, a martensitic phase transition in a steel "cork" at the top of the expansion chamber causing it to move upward from the chamber and let the reaction mass flow into the chamber when the engine was heated to the right temperature by the laser).

The advantage, of course, is that the laser device itself could be as large as needed, and powered by whatever it needed to be - CoIL, its own dedicated nuclear reactor, MHD plasma chamber... because IT wouldn't be going anywhere. And the cryogenic could be liquid nitrogen, liquid air, LOX, LH2, water... whatever was practical. No moving parts, except those which "moved" by thermal expansion out of the way of the reaction mass. loupgarous (talk) 08:31, 27 August 2014 (UTC)

What do you think the cushion is made of?

Thx. Ben-Natan (talk) 13:11, 22 August 2014 (UTC)

Waffle fabric? --Jayron32 13:46, 22 August 2014 (UTC)

I ask myself if there is any Leather in it?, Or how high are the chances it's filled with feathers or wool? Ben-Natan (talk) 14:00, 22 August 2014 (UTC)

This is really into speculation territory, but seems harmless. I assume you can't physically examine the object, or then you probably wouldn't need to ask. Anyway, I see no indication of leather. It is possible some old rattan and wicker work might use leather for lashing, but it is not common in my experience, and leather is much more expensive and less durable than other options (synthetics, integral woven wicker, etc.) I suspect the odds of wool or down stuffing to be very low. Cushion indicates a variety of stuffings, but most stuff made in the past ~40 years will have synthetic stuffing or perhaps cotton batting. The simple reason is that synthetics are much cheaper, and last longer, even if they don't feel quite as nice. Wool and feathers can both be allergenic, which is another reason to avoid them. I'd only expect to see wool or feathers in rather expensive furniture, which this does not seem to be (I do like the chair, it just doesn't seem like an expensive model to me :) SemanticMantis (talk) 17:21, 22 August 2014 (UTC)

As long as we're speculating, my first thought, given the cushion's thinness and lack of lumpiness, was foam rubber. Deor (talk) 20:02, 22 August 2014 (UTC)

What is a phone number?

A person can move elsewhere in the same town and take his or her landline phone number along instead of changing it, or even change it to a cell phone number. Or if that person is being harassed, he or she can change landline phone numbers. Or different people in the same house can have different landline phone numbers. I thought I had the answer to this question when I discovered the concept of IP address. But several branches of the same library system and several hotels in the same resort community have the same IP address when I try to edit Wikipedia without signing in. Plus AOL has dynamic IP addresses. And apparently unlike me, most people get their Internet service through the cable company. So there must be something comparable to an IP address that the phone company uses to identify you.— Vchimpanzee • talk • contributions • 18:10, 22 August 2014 (UTC)

Well, this question becomes a lot simpler if you consider common phone systems from e.g. 1980 or so. The reason being, Telephony services and IP phones now underlie even basic "land line" services in many areas, so in some cases there aren't that many distinctions between phone service and internet service. This is especially true for things like businesses, universities, hotels, etc., as it is now often less expensive to use the internet for calls in situations where you want a lot of phones in a relative small spaces. For the historical perspective, see Telephone_exchange, Public_switched_telephone_network, Telephone_numbering_plan, and even Telephone number. So, today the line between "phone number" and internet services is very blurry, but in the past, the phone systems basically worked via phone companies assigning numbers to customers, and using manual or digital switch devices to route calls. The key distinction is that the old phone networks had fixed cables, and calls had to travel down certain paths to be connected. With modern Packet switching (e.g. the TCP/IP that supports the internet), any given packet might take a different path between host and client. (I think I got most of the basics here right, but of course welcome clarification or correction if necessary) SemanticMantis (talk) 19:35, 22 August 2014 (UTC)

I guess what I'm trying to accomplish is something like what cops do in movies or TV shows. Thanks for trying.— Vchimpanzee • talk • contributions • 20:31, 22 August 2014 (UTC)

You mean like a call tracing or Telephone tapping or something? Cops do lots of things on tv, not sure what you might be thinking of. If you're interested in the kinds of shenanigans people can get up to with phones, you might be interested in phreaking. Again, it was a lot different in the past, I don't think whistling into the phone will get you free calls these days :) SemanticMantis (talk) 20:42, 22 August 2014 (UTC)

• For cell phones, each phone has a unique identification key entered on its SIM card, which the phone company uses to identify that phone and look up its subscriber information (including phone number) in a database. For landline phones I don't think there is any such universal system -- each phone company is allowed to implement the mapping from phone number to physical signal route in any way it wants to. Looie496 (talk) 21:12, 22 August 2014 (UTC)

As mentioned below, for landline phones, the mapping is all in the wiring. The copper wire is the physical signal route. Robert McClenon (talk) 21:42, 22 August 2014 (UTC)

To quibble for the sake of it, the IMEI is stored on the phone itself. The unique number on the SIM is the IMSI. Tevildo (talk) 21:22, 22 August 2014 (UTC)

No, there doesn't have to be anything unique in your landline phone for the phone company to identify it or you. (Some of the above answers were unique to cell phones.) Your landline phone or phones are the only phones that are at your end of a wire connection. You have a dedicated wire connection between the telephone exchange and your house. If you move from one location within the area served by a particular exchange to another location in the same exchange, the wire to your new location is connected to the switch connection for that number. ("Exchange", in 'telephone North America', is the NNN part of the 1-NPA-NNN-XXXX that is your telephone number.) That is also why you can use multiple handsets in your house without involving the phone company (assuming that you don't put too many handsets on, and so exceed the ringing impedance). There is nothing in a landline phone that identifies it to the phone company. It is the wiring that is unique. Robert McClenon (talk) 21:39, 22 August 2014 (UTC)

As former Bell employee from a family of Bell employees who manually wrote orders in code providing service, changing and moving numbers, and switching them between companies, I can confirm McClenon's answer is correct for land lines. μηδείς (talk) 01:45, 23 August 2014 (UTC)

By the way, what is shown on police procedural TV shows, getting a list of calls to and from the victim, is done using telephone metadata, consisting of records of calls. There is one metadata record written for every call that is attempted (whether or not it was completed), showing, among other things, the calling number, the called number, the status of the call (no answer, busy, completed), the length of the call, et cetera. The phone company collects the metadata for various purposes of its own, such as long distance billing, capacity planning, maintenance. It is also secondarily used by the police and for other purposes (e.g., formerly, by NSA acting as the secret police). The metadata is essentially the same for landline phones and for cell phones. Robert McClenon (talk) 21:39, 22 August 2014 (UTC)

Telephone numbers started off as Plain Old Telephone service or POTS. Literally the number eventually desc a pair of wires (a 110 punch down is very old). As computer and electronics progressed, only the last mile remained unchanged. Terms like T1 were based on the number of twisted pairs (24 for T1 if I recall and a T3 was 3 T1 bundles). Gradually, the phone system migrated from the physical layer description to different levels of abstraction but as long as it ended at a single pair, it worked. TCP/IP I believe is about 7 levels of abstraction from the physical wire. A telephone number today is simply a backward compatible description of a what was a much more physical model of switches and exchanges that described exactly where a pair of wires went. Note that two-wire POTS still works though it will be converted at the exchange to a more modern form. Old modems and Fax machines still have the POTs Data access arrangement and Tip and ring functionality and wire designation. There is a limit of phones that can exist on the tip/Ring pair and phones came with a Ring equivalency number. Equipment for phones was (and is regulated to allow tracing and pen registers. It certainly is possible to put equipment on the subscriber side, it's much more discrete to monitor at the switch. Also, with digital landline equiment, intercepting at the switch level gives much more information about the call. Cell phones only use their hard-coded network ID to request temporary ones which makes it more difficult. In the U.S., I believe latest implementations encrypt the temporary key so it requires the assignment log at the tower switch to know the assignment so it's not available as a simple radio intercept (and even before encryption the requests for new temps are infrequent). There are specific law enforcement tools that can be used in close proximity to the physical phone (i.e. cell tower range) to access and monitor calls under certain conditions. This is a requirement mandated under the spectrum leasing by the FCC. There are other tools that are available for longer term/wider area access. All of these requests, I believe, are funneled through a single federal LE agency to the carriers or other providers. --DHeyward (talk) 04:59, 25 August 2014 (UTC)

Using nukes to create graphene

Say you take a cylinder of carbon. Put two shaped nuclear charges on both ends of the cylinder and detonate them. Would this create graphene? Malamockq (talk) 23:51, 22 August 2014 (UTC)

If it did, it would also spread it over a wide area, making the experiment rather pointless. And which form of carbon are you proposing to start with? AndyTheGrump (talk) 00:16, 23 August 2014 (UTC)

What do you mean spread it over a wide area? I don't know what form of carbon. Whatever might produce graphene I suppose. Malamockq (talk) 01:21, 23 August 2014 (UTC)

Is the point to ignite wildefires, then collect the graphene from the soot? μηδείς (talk) 01:39, 23 August 2014 (UTC)

I was thinking it would be more prudent to detonate it underground. Malamockq (talk) 03:42, 23 August 2014 (UTC)

I don't believe high pressures are needed to produce graphene. It's basically just a very thin sheet of graphite. At least according to Superman comics, what you describe might end up producing diamond. Rojomoke (talk) 05:07, 23 August 2014 (UTC)

♦ 84.209.89.214 (talk) 12:05, 23 August 2014 (UTC)

Right, this would probably produce diamonds. You don't even need nuclear bombs to do it. It can be done with conventional explosives. If you have a piece of graphite, all you need to make graphene is some adhesive tape. Mr.Z-man 13:38, 25 August 2014 (UTC)

No, you cannot, like putting a grenade in a wax block doesnst produce Honeycombs. Graphen is being grown on structured layers, the bees are rather tiny ones compared ;) Serten (talk) 17:40, 26 August 2014 (UTC) You get soot or Impactites - but no diamonds. A diamond needs a longer time of high pressure to grow. Serten (talk) 17:46, 26 August 2014 (UTC)

At least follow the links. Nanodiamonds are still diamonds. Andre Geim and Konstantin Novoselov got the Nobel prize for getting graphene using sellotape.. Dmcq (talk) 17:51, 26 August 2014 (UTC)

The only actual experimental experience with graphite in the vicinity of nuclear detonations was coating steel spheres suspended from cables near a nuclear device with graphite. The result (after the nuclear detonation) was that instead of steel vaporizing from the body of the spheres, the graphite vaporized instead. No changes in the structure of the graphite itself were reported. This experiment led to the idea of coating the "pusher plate" on the Project Orion nuclear detonation-propelled spacecraft with oil or graphite between nuclear propellant pulses, so that ablation of the plate itself would be prevented or reduced. loupgarous (talk) 07:05, 27 August 2014 (UTC)

August 23

Furnace cement

Furnace cement seems to have little in common with Portland cement. Wikipedia does not appear to have an article on it. In particular, per its material safety data sheet, "Imperial Hi Temp Stove & Furnace Cement" by Kel Kem LTD, Ontario, Canada is an asbestos-free product for filling chinks around a fireplace or like high-temperature applications. It is a blend of Silica quartz (40-70%), Hydrous Aluminum Silicate (15-40%), Sodium Silicate (10-30%) and Sodium Hydroxide (1-5%). (I don't understand the stated extremely wide variation in their own statement of the composition). The directions say wet the surface, then apply with a wet trowel, allow to air dry for 24 hours, the heat it up gradually to cure it. It says it must be heat cured, and that it is not for exterior applications. it is rated for use up to 1482C (2700F). So my question is, is there some chemical reaction when it is heated to cure it, and what would that reaction be? Does some form of glass appear when it is heated, like Porcelain,or does it just dry and get hard because the water goes away? None of the chemicals seem similar to the clays which go into Pottery. Thanks. Edison (talk) 00:33, 23 August 2014 (UTC)

I've got a tub of fireclay, tho it actually calls itself refractory mortar. I'd say it just dries out but there is some chemical reaction as it doesn't immediately soften when wetted again. Greglocock (talk) 00:48, 23 August 2014 (UTC)

The chemicals listed do not appear to be "clay" right? If you heat clay, you get pottery or porcelain. If you heat Portland cement or concrete in a furnace, it gets crumbly and falls apart. But what is going on here? Edison (talk) 01:04, 23 August 2014 (UTC)

Try Refractory, under the 'Castable' heading. The link there to Fire clay also looks promising. --Heron (talk) 08:50, 23 August 2014 (UTC)

But not the same ingredients. Clay minerals lists " hydrous aluminium phyllosilicates." Is the "Hydrous Aluminum Silicate" the same? Are the chemicals in this product the same as other clays listed in Clay minerals, but with different nomenclature? ("Dickite" for instance. hahaha) Edison (talk) 17:32, 26 August 2014 (UTC)

Song identification after one musical note

I've decided to post the question here (and not in Entertainment) since it may (or may not) involve the brain's cognitive abilities. I've been briefly watching the Polish version of Name That Tune and there many folks correctly identified songs after hearing just one note (not even two). Even though they are given hints, I think it's almost impossible to ID a song after one note (I remember the old Russian version hosted by Valdis Pelšs, where players normally decided to hear at least two notes, but not one). Is it actually true or there's some foul play involved in guessing just after one note? Brandmeister^talk 11:10, 23 August 2014 (UTC)

If it was the first note of A Hard Days Night, it wouldn't be too hard. HiLo48 (talk) 11:27, 23 August 2014 (UTC)

AHDN is introduced by a chord which is several notes. Just a drumroll is enough to bring an audience to their feet singing the national anthem - if you happen to be in a British theater where the queen is expected to arrive. Music is shaped by expectation. Could the first note of this be anything other than this? 84.209.89.214 (talk) 11:43, 23 August 2014 (UTC)

So it's not just the note, it's the orchestration, right? If the host of the show were at a piano and simply hit some particular key, it seems unlikely they could do any more than guess. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:44, 23 August 2014 (UTC)

Yes, but the hints can be pretty good give-aways; that's the trick on the "one note" guess. Someone good with music trivia doesn't need notes at all; they just know enough pop music to be able to get the song from the clues alone. --Jayron32 19:35, 23 August 2014 (UTC)

When Name That Tune was on UK television (many, _many_ years ago), the contestants generally worked out the tune from the description, and didn't really need the single note to confirm their answer. Tevildo (talk) 14:03, 23 August 2014 (UTC)

Plan a half hour to listen to this properly but any Norwegian can tell what it is from the first note. We like you to enjoy. 84.209.89.214 (talk) 22:29, 23 August 2014 (UTC)

To which there is only one possible response... Tevildo (talk) 22:41, 23 August 2014 (UTC)

Whey protein

Can whey protein cause ibs or stomach issues in the long term? 82.132.216.31 (talk) 13:27, 23 August 2014 (UTC)

See Whey protein and irritable bowel syndrome for our articles. As the causes of IBS aren't known, it's not possible to say whether or not any particular diet can affect it. Tevildo (talk) 15:44, 23 August 2014 (UTC)

The scientific method could be used here, where one group of test subjects has a diet devoid of whey protein, and another group has a diet identical to the first group, except for the presence of whey protein. After the test period, the two groups could swap their diets for a 2nd test period of the same length. Questionaires would be used throughout, to tell if there is any noticeable difference in IBS symptoms. Or you could simply count the number of bowel movements per day, to make it less subjective. StuRat (talk) 21:31, 23 August 2014 (UTC)

Double-blind trial and Koch's postulates might be better starting points. Tevildo (talk) 22:49, 23 August 2014 (UTC)

The first link is applicable, but the 2nd is for diseases caused by organisms, while, if whey protein contributes to IBS, it would be likely due to an allergic reactions. StuRat (talk) 17:17, 24 August 2014 (UTC)

Despite the known sciency-ness of responders to the Wikipedia help desk, I doubt scientists have overlooked the scientific method. Rather I suspect both IBD, diets, allergies and whey protien to have far more intricate levels of interaction that have so far escaped science. Putting people on regimemted diets will affect them. So will consumption of foods (see latex allergy for the gradual emergence). The permutations and sample size along with subjective criteria will make definitive causation to be scientifically elusive. Even the time spans are difficult as the experiment has to be long enough to initiate the effect yet short enough not to be affected by other uncontrollable events such as seasons, aging or even as short as monthly hormonal cycles. To summarize, eat it. If you puke, get diarrhea, constipation or die - stop eating it. If you develop a condition over time, stop eating it. Note that it will be nearly impossible to physically isolate your IBD to Whey protein. However, your own empirical observation, (whether physical in origin or psychological or random) is probably more important to you as you assess your situation in the WC think tank. --DHeyward (talk) 05:21, 25 August 2014 (UTC)

One of IBS's top theories is related to bacterial flora, which are "organisms." --Wirbelwind(ヴィルヴェルヴィント) 23:25, 26 August 2014 (UTC)

Yes, based on my decidedly non-scientific survey of sources online (googling "whey protein and IBS") as well as my own recollection of nutritional research into the adverse health effects of cow's milk in general. On a common sensical/biological level, you might wonder why humans are the only species to drink another species' milk (cow, goat, etc) and even those species don't drink their mother's milk after a certain young age... but then maybe I'm a bit biased as a vegan. El duderino ^(abides) 13:40, 25 August 2014 (UTC)

Lactase persistence which enables adult humans to digest milk and dairy products beyond infancy is often cited as an example of recent human evolution correlated with the rise of dairy farming. As dairy farming originated in Europe, Europeans were exposed to increased lactose nutrition provided by dairy products, resulting in positive natural selection. The supply of fresh milk leads to the favoring of the lactase persistent trait.

Unlike ovo-lacto vegetarians, vegans object to dairy farming where female calves are separated from their mothers within 24–48 hours of birth and fed milk replacer, so that the cow's milk is retained for human consumption, and will be kept pregnant through artificial insemination to prolong lactation. 84.209.89.214 (talk) 14:32, 25 August 2014 (UTC)

Measurement of a standing object's stability

How the stability of a free-standing object is measured (in what units)? For example, of a one-legged torchère vs. three-legged tripod? Or of persons with different weights or of two persons with one's legs close to each other and the other person with his legs apart for more stability?--93.174.25.12 (talk) 19:57, 23 August 2014 (UTC)

You may find this lesson or maybe this lesson a good introduction; the relevant Wikipedia articles would be at center of gravity and moment of inertia. Stability is determined by whether or not an objects center of gravity is raised or lowered as a result of a force. An object's position is inherently unstable if its center of gravity is easily lowered by a small push in any direction. An object is inherently stable if no motion could lower the center of gravity (that is, the center of gravity is in the lowest possible position). An object would be metastable if the center of gravity is NOT in the lowest possible position, but where any push would still result in an initial raising of the center of gravity (that is, you would have to lift the center of gravity some before thw object spontaneously fell over). If you wanted to put a number on stability in this way, these concepts can be quantified using gravitational potential energy; the difference in gravitational potential energy between an object's current position and its most stable position would be it's instability, the SI unit for such measurement would be the Joule. If you are familiar with chemistry, this quantification of positional stability is exactly analogous to the Reaction coordinate diagram used in chemical kinetics and thermodynamics. Indeed, the concept of "stability" in this way is universal in physical sciences; the difference is in applying the general idea to specific situations, whether it be chemical reactions or things falling over. --Jayron32 20:10, 23 August 2014 (UTC)

Also, there can be dynamic stability, such as a spinning top that is stable so long as it spins, then falls over when it slows down. StuRat (talk) 21:25, 23 August 2014 (UTC)

The simplest answer is probably 'degrees'. In tests like this, they just tilt the object until it starts to fall over. The angle of tilt is a good measure of stability. --Heron (talk) 08:22, 24 August 2014 (UTC)

For boats, metacentric height (measured in units of length) is the relevant parameter. It would be easy to calculate this for a land-based structure, but I don't believe this is done routinely. Tevildo (talk) 09:12, 24 August 2014 (UTC)

Skyscrapers do something similar and to counteract sway (which can be substantial in upper levels), they often place a large mass at the top that is moved around to limit sway and nausea. Damping is the term I would use to describe stability but it leaves out cases that appear stable until perturbed (i.e. ball ot top of a hill -> meta-stable?). Resonance is another related concept to stability. --DHeyward (talk) 05:32, 25 August 2014 (UTC)

houseplants peperomia obtusifolia trouble

I took cuttings of my Peperomia Obtusifolia that had a severe accident, and have been attending them for the past week or so. I left them unnoticed (I have a lot of plants) for a few days, and noticed that they are dry to the bottom. It's four in the afternoon, very cloudy, and an apt. building wing blocks the direct Sun from my windows. Do I water anyway, or wait for the sunny day tomorrow? Thank you for your interest. Ed Meissner

This is a question, not an answer, because I have not grown Peperomia for years. But I'm wondering why you think you maybe should not provide water when it is dried out. C7nel (talk) 21:16, 23 August 2014 (UTC)

The OP seems to think that plants should only be watered when sunlight is on them. I've not heard that, but I suppose it might keep mold down. Personally I think watering them whenever they are dry is best. StuRat (talk) 21:23, 23 August 2014 (UTC)

I agree with StuRat, you should keep them damp and I think you should not allow direct sun onto the cuttings. Richard Avery (talk) 07:11, 24 August 2014 (UTC)

August 24

Maxwell's equations

The article Computational electromagnetics states Maxwell's equations as:

${\frac {\partial }{\partial t}}{\bar {u}}+A{\frac {\partial }{\partial x}}{\bar {u}}+B{\frac {\partial }{\partial y}}{\bar {u}}+C{\bar {u}}=g$

Someone please define $g$ in the above equation (this question is from the article Talk page). 84.209.89.214 (talk) 17:11, 24 August 2014 (UTC)

In this case, g is the generalized forcing function. Are you familiar with general solution methods for inhomogeneous differential equations? If not, that is where you ought to start reading. By extension to the 1-D case, g is the nonhomogeneous part, and it is a vector in the same space as u (as formulated above).

In physical terms (if you're one of those pesky "touchy-feely" computational electromagneticists who want to intuitively understand the equations), g is the representation of any "externally-applied" field.

The reason I express caution (rather, when I use wikt:touchy-feely in usage (2), ergo, with derogatory connotation), is that in practice this term is a sort of "garbage dump" for any other term in the equation. It can be an externally applied field. But it can also be a minimization constraint, or a nonlinear function in u, or anything else. If you really want to make use of it, you must understand that g is simply "the nonhomogeneous part of the equation": nothing more, nothing less.

Nimur (talk) 21:25, 24 August 2014 (UTC)

Thank you for your good answer and edits to the article. I suggest $g$ can be written ${\bar {g}}$ for notation consistency. 84.209.89.214 (talk) 12:39, 25 August 2014 (UTC)

I think you are correct, ${\bar {g}}$ makes more sense for consistency. When I first read that article section, I interpreted the overbar to mean that u was a vector of vectors, $({\vec {E}},{\vec {B}})$, but in fact whoever defined it actually wrote individual components and reduced to a simplified 2-D case. (This allows explicit specification of the elements of matrices A, B, C, which appears to be the actual purpose of the section). So, it seems we should use an overbar on ${\bar {g}}$. Notational consistency is a sore point on Wikipedia; this is one of the chief advantages that a conventional textbook source can provide. Personally, I've seen so many variations that I've totally given up on notation: my philosophy is, if it's not written in compile-able program code, I consider it "approximately notated, designed for human consumption (hand-waving implicit and expected)." Nimur (talk) 15:44, 25 August 2014 (UTC)

Electricity

list safety precautions required for series and parallel connections — Preceding unsigned comment added by 197.111.223.245 (talk) 20:02, 24 August 2014‎

We're not going to do your homework for you. Jc3s5h (talk) 20:26, 24 August 2014 (UTC)

First, be sure you're wearing insulated gloves. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:13, 24 August 2014 (UTC)

And learn how to spell the word. HiLo48 (talk) 21:26, 24 August 2014 (UTC)

Which one? —Tamfang (talk) 22:39, 25 August 2014 (UTC)

This section was headed "electrity"[2] until an alert editor cried out, "I C!" ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:42, 27 August 2014 (UTC)

The safety precautions you need depends on the voltage and currents you will be working with. Some information is given by High_voltage#Safety. Ulflund (talk) 21:48, 24 August 2014 (UTC)

For me, it's a short list. Step 1: Turn off the electricity. --DHeyward (talk) 05:36, 25 August 2014 (UTC)

No "Step 2: take whatever actions are necessary to make sure nobody undoes Step 1."? DMacks (talk) 05:43, 25 August 2014 (UTC)

People: This is a question about safety. A rather vague question in my opinion. Does anyone understand the question well enough to give a proper safety-conscious answer? If not, wouldn't the wisest course be to NOT give answers? CBHA (talk) 06:07, 25 August 2014 (UTC)

Well, the question requires the OP to regurgitate whatever was in the course notes, whether or not that's true or accurate. The actual safety precautions required for electrical work will depend on jurisdiction and the voltages involved (and, if we knew those details, we could give a proper answer), but this question just a "Wakalixes makes it go" test of the OP's memory. Tevildo (talk) 08:32, 25 August 2014 (UTC)

The main thing I think of where parallel connections are concerned is that each component can, potentially, create a short in the system or something near to one that might start a fire. But yes, you need to give more information. Also, I'm thinking if you're asking for safety tips on the Internet maybe you need an electrician. :) Wnt (talk) 10:26, 25 August 2014 (UTC)

Too vague a question. Safety precautions vary from designed in safety precautions such as current limiting devices as well as actions such as "how to work on a solar array without dying." Solar for example has both parallel and series wired panels and the short circuit problem is not nearly as problematic as the open circuit problem on the DC side. There's no mechanical off switch that will de-energize the array. --DHeyward (talk) 23:31, 25 August 2014 (UTC)

Nyuk, nyuk, nyuk! I'll fix that! (Shakes can of black spray paint) :) Wnt (talk) 13:00, 26 August 2014 (UTC)

Sliding a cover over it or pointing the panels at the ground ought to do it. StuRat (talk) 15:17, 26 August 2014 (UTC)

But that wouldn't be funny! Wnt (talk) 17:22, 26 August 2014 (UTC)

Covers are usually used. Still there is a separate section on solar array installations in the U.S. NEC that are safety related and constantly evolving. The differences are large enough that we will eventually see deaths and fires. This has already happened on small scales. The deratings required for main circuit breakers for fault tolerance, for example are not intuitive to average electricians (not even a factor for home systems ~5kW). Breaker location for grid-tie inverters is based on fault tolerance, too. I saw a backfeed design that was 250 amps into a 2000 amp service. The kicker was that the 2000A main breaker was to protect the switchgear. Adding 250 amps of potential fault current means the mains had to be derated to 1600 amps (the next lowest setting available). Kind of a big deal if they needed the 2000 amps. They were fortunately at the load limit at 1600 amps and could do it without upping the switchgear. Now, the instruction to reset the main breaker to 1600A is engineering instruction. The installer didn't do it because they see the solar array as source that offsets the incoming power, not as a source of fault current in addition to the 2000A of fault current. Kind of a bummer to add 250A of solar but reduce the site by a net 150A because of fault current limit in the switchgear. The Solar marketing guy did not like having that conversation with his customer. It's a mindset that is part of the code for solar but very counter-intuitive to electricians and contractors and Marketing. --DHeyward (talk) 06:53, 27 August 2014 (UTC)

August 25

Formula 1 steering wheel

I stumbled upon this photo of a Formula 1 steering wheel. Where can I find explanations about the function of each knob? TIA Zarnivop (talk) 12:27, 25 August 2014 (UTC)

Kde Pazletz. Found it! Zarnivop (talk) 12:35, 25 August 2014 (UTC)

The OP has stumbled on the steering wheel of the Sauber team C33 Formula 1 car. This reference guide is handy while driving. The PCU-8D LCD screen, made by McLaren Electronics, is 4.3 inches wide with a resolution of 480 x 272 pixels. It can display as many as 100 pages of info such as engine RPM and oil temperature, current lap speed and how many laps remain. [3]. The buttons are colour coded.

• Yellow N button: Selects neutral from 1st or 2nd gear.
• BRKBAL (brake balance) rotary switch: Adjusts the front and rear brake balance.
• Black Box button: Confirms the driver’s intention to come to the pits.
• Blue and orange S1/S2 buttons: These can be programmed for various functions.
• Entry rotary switch: This allows the driver to make changes to corner entry settings of the differential.
• Orange and green BRK-/BRK+ buttons: These change the brake balance between a programmed position and the current BRKBAL rotary position.
• IGN (ignition) rotary switch: Controls ignition timing.
• White ACK (acknowledge) button: Acknowledges changes in the system.
• PREL (preload) rotary switch: Controls the preload differential offset torque.
• Red Oil button: Transfers oil from the auxiliary tank to the main tank.
• Black BP (bite point) button: Activates the clutch bite point finding procedure.
• DRS (drag reduction system) button, upper left edge of the wheel: Activates the rear wing flap in the DRS zone.
• Red PL (pit lane) button: Activates the pit lane speed limiter, limiting the car to the designated pit lane speed limit (typically 100 km/hr).
• Black R button: Activates the driver radio transmission.
• SOC rotary switch: Controls the state of charge of the ERS energy storage system, whether the system is generating or consuming energy.
• Pedal rotary switch: Changes the pedal map dictating how the accelerator pedal responds to inputs.
• Fuel rotary switch: Controls the rate of fuel consumption.
• Black OT button: Activates configurable performance maps to assist the driver in overtaking or defending.
• Tire rotary switch: Tells the ECU and other systems what type of tire the car is running on.
• BBal-/BBal+ switches: These are used to make fine adjustments to the brake balance offset.
• MFRS (multi-function rotary switch): This allows the driver and engineers to control a variety of systems that don’t require a dedicated buttons. They include engine modes (PERF), rev limiter (ENG), air-fuel ratio (MIX), turbo-compressor (TURBO), corner exit differential (VISCO), MGU-K recovery limits (BRK), MGU-K boost limits (BOOST), dashboard options (DASH), cruise control (CC, disabled for qualifying and the race), shift type (SHIFT), and the clutch bite point offset (CLU).
• White -10/+1 buttons: These allow quick navigation of maps from the MFRS dial. 84.209.89.214 (talk) 14:04, 25 August 2014 (UTC)

• Is this used to play an electronic car racing game, as opposed to actually being used in a race car? (In a world where they worry about drivers getting distracted by texting or chatting on a cellphone) Edison (talk) 17:20, 26 August 2014 (UTC)

It's the real deal. Race driving is completely different from real world driving. Much more predictable behaviour on the part of other drivers, so the types of distractions are different. Mingmingla (talk) 18:17, 26 August 2014 (UTC)

A lot of the buttons are almost exclusively used in the pits, when making adjustments to race settings. But when there's a problem detected during a race in things like break balance, for example, it's important for the driver to be able to adjust things on the fly without having to go in for a pit stop. Race strategy will also dictate when you want to lower the fuel consumption rate, so it's important for the driver to be able to control that; smae for the activation of DRS and the buttons related to pit stop protocol. For a lot of these buttons, the drivers don't even need to take their eyes off the road, or only for a fraction of a second, to activate or deactivate the function. --Xuxl (talk) 09:01, 27 August 2014 (UTC)

I saw Talladega Nights: The Ballad of Ricky Bobby and none of that is needed. Just need to go fast. Maybe a cougar. --DHeyward (talk) 07:02, 27 August 2014 (UTC)

August 26

Is plasmid supercoiling sequence dependent?

Is plasmid supercoiling sequence dependent?

It will depend on sequence and ionic conditions together. Extreme cases are Z-DNA and triple-stranded DNA formation. Wnt (talk) 17:21, 26 August 2014 (UTC)

Yes, mechanical properties of DNA do indeed depend on sequence, as well as other factors. There is also some relevant info at DNA supercoil and Nucleic acid tertiary structure. Of note "Additionally, certain enzymes such as topoisomerases are able to change DNA topology to facilitate functions" -- e.g. there are enzymes that can add/remove twist, which changes the whole structure. Remember, unless you crystallize it, DNA is a very gangly, floppy thing, and it will take on different structures, depending on what it's doing. Another extreme example is that certain thermophilic archaea have "overtwisted" DNA, compared to "understwisted" supercoils that are prevalent at more normal temperatures. I can't find anything on WP about that, but this paper goes into it a bit [4]. This one describes how positive and negative supercoiling can both be useful, regardless of themophilic/mesophilic status: [5]. SemanticMantis (talk) 18:20, 26 August 2014 (UTC)

Thanks for the interesting article about the thermophilic archaea. So that's how people think the earliest DNA would have evolved and acted, it is quite surprising. Dmcq (talk) 19:30, 26 August 2014 (UTC)

I agree it's interesting, but I'd also be careful with what conclusions we draw. From the article: "Archaea were initially viewed as extremophiles living in harsh environments, such as hot springs and salt lakes, but they have since been found in a broad range of habitats, including soils, oceans, marshlands and the human colon and navel" -- in short, it's not clear to me that the extremophilic archaea are in some sense primitive. E.g. soil archaea may be more primitive, and might have "normal" DNA negative supercoiling. SemanticMantis (talk) 19:57, 26 August 2014 (UTC)

Purpose of naming new chemical elements and small moons

New chemical elements and new moons are named in order to honor scientist/laboratories or gods/deities. However, they aren't very relevant in their respective sciences and people won't use the names very often if at all. Naming makes everything complete although IUPAC and IAU always need much time for it. Are these names ever going to be practical? I think just using numbers would be enough. In Chinese for example, new characters have to be invented for every new chemical element and most Unicode versions don't support characters beyong element 103, so most keyboards can't type them anyway. On the contrary, moons are just numbered in Chinese. --2.246.3.119 (talk) 20:00, 26 August 2014 (UTC)

"Extended periodic table" has an interlanguage link to the Chinese version at zh:扩展元素周期表, which does show names for some elements beyond Z (that is, atomic number) = 103.

—Wavelength (talk) 23:07, 26 August 2014 (UTC)

If you look at that table, the high numbered elements without symbols are "钅" followed by another character, while the more familiar ones have specific characters that combine the two symbols side by side ([6]). But the second characters are symbols that already exist in the language. Wnt (talk) 00:40, 27 August 2014 (UTC)

Exactly. Every metal has the radical 钅 and every element corresponds to only one character. The table you linked above shows two characters for each element from 104 on, which looks very awkward. There may be unicodes for them, but the way the Chinese Wikipedia handled it proves that most computers wouldn't be able to see these new characters, so they decided to break them up into two. Most Chinese dictionaries have the periodic table on the very last page and they always print a new version when a new element has received its name. Of course, the characters won't look odd in dictionaries. --2.246.3.119 (talk) 00:55, 27 August 2014 (UTC)

"A superior man, in regard to what he does not know, shows a cautious reserve. If names be not correct, language is not in accordance with the truth of things. If language be not in accordance with the truth of things, affairs cannot be carried on to success. When affairs cannot be carried on to success, proprieties and music do not flourish. When proprieties and music do not flourish, punishments will not be properly awarded. When punishments are not properly awarded, the people do not know how to move hand or foot. Therefore a superior man considers it necessary that the names he uses may be spoken appropriately, and also that what he speaks may be carried out appropriately. What the superior man requires is just that in his words there may be nothing incorrect."

— Confucius, Analects, Book XIII, Chapter 3, verses 4-7, translated by James Legge loupgarous (talk) 05:53, 27 August 2014 (UTC)

I imagine new elements get named because it's an old tradition and also allows the discoverers to honour whatever or whoever they feel is important to them. Now of course finding new elements gets progressively harder and harder (if you're interested, we simply do not yet have the technology required to make elements with Z > 120), so the naming becomes increasingly important and fraught with significance because you will most likely not get to name all that many elements. And now the work is done in teams, so the team must come to an agreement on this issue which now seems very, very important: it is their one chance to get their desired reference to somewhere or someone onto the periodic table, where it will be remembered forever.

Consider Glenn T. Seaborg's reaction to the naming of seaborgium after him, three years before he died:

"This is the greatest honor ever bestowed upon me--even better, I think, than winning the Nobel Prize," said Seaborg, the co-discoverer of plutonium and nine other transuranium elements. "Future students of chemistry, in learning about the periodic table, may have reason to ask why the element was named for me, and thereby learn more about my work." (ref)

"Element 106" just doesn't feel as significant and important, does it? Yes, it's very short-lived, but it sticks around long enough to do chemistry and form compounds like SgO₃ or [SgO₂F₃]⁻. And what if we reach the island of stability around ³⁰⁶122 and find really long-lived nuclides, perhaps long enough to be practical? It would then get silly to keep calling them by the atomic number – the general public will want a snappier name. (A simple extrapolation of the half-lives of element 113 isotopes would mean that around ³⁰⁵113, the half-lives could get to the ²³²Th or even ²⁰⁹Bi range – this was, I think, first pointed out by Difluoroethene on Talk:Ununtrium. Now, I think the trend will probably turn around sometime in the middle, but I'm not ruling this out.)

Now, I don't know so much about naming new moons. It does create shorter names than the temporary IAU names like S/2007 S 3, but some small Jovian and Saturnian moons have renamed unnamed for years now. Some time ago there was indeed a problem because too many moons were being discovered and there just weren't enough characters from Greek and Roman mythology to be used as names that would fit the rules. So they got widened. I wonder if that might have happened again with the broadened rules? There's also the thing about these new moons being so small (come on, 1 or 2 km?!) that some people feel they shouldn't be called "moons". Double sharp (talk) 08:19, 27 August 2014 (UTC)

Reliable source for vitamin dose suggestions

My experience at pharmacies is that there is a very wide range of vitamin pills sold over the counter. Several brands, many different vitamins, and a wide range of "strengths" of a particular vitamin even within the same brand.

For example, (looking at three brands of Vitamin B Complex), I see Vitamin B6 (biotin) in amounts of 5 mcg, 60 mcg, and 500 mcg per pill. And Vitamin B12 (cyanocobalamin) in amounts of 10 mcg, 50 mcg, and 1000 mcg per pill.

Is there any more or less reliable source to turn to for answers to questions related to vitamin doses? Eg, looking at these products, I can't help but wonder - Is 10 mcg of Vitamin B12 a reasonable amount, in which case 1000 mcg is an absurd, wasteful, perhaps dangerous overdose? Or is 1000 mcg a reasonable amount, in which case 10 mcg is a trivial amount to bother with at all?

Please note I'm NOT asking the reference desk to tell me how much Vitamin B12 to take. I'm asking if there is a reliable source for answers to questions such as this. Thanks, CBHA (talk) 20:36, 26 August 2014 (UTC)

Our Vitamin article contains several such links - this is the one from Health Canada, although the equivalent US table is giving us a 404 at the moment. Incidentally, is "mcg" milli-centi-gram (0.00001 g)? An odd unit, if so. Tevildo (talk) 22:46, 26 August 2014 (UTC)

Quick follow-up - the USDA doesn't seem to maintain its own RDA chart any more, but this is their reference page. Tevildo (talk) 22:55, 26 August 2014 (UTC)

Tevildo, mcg is frequently used in the U.S. for microgram. Deor (talk) 23:06, 26 August 2014 (UTC)

I think it's worth noting that there was a terrible idea to use a non-English alternative to mcg (or the informal but practical "ug") in the scientific literature, namely µg. The problem with this is that for a long time pre Unicode it was typically a lowercase "m" in a symbol font, and any change in the font of a document meant that it became an m. So even in a professionally published scientific paper with no corrections, whenever you see "mg" or "mmol" or "ml" you always have to be wary it's really µg or µmol or µl. And if you see text that's been folded spindled and mutilated through some kind of automated processing into a database, you know it's random. Now fortunately this has been going away by leaps and bounds recently, but I suspect it has taken a heavy toll. For example, I remember I was really suspicious that the factor-of-1000 error that killed the Venezuelan polo team's horses could have been one of those word processing things. Wnt (talk) 00:28, 27 August 2014 (UTC)

Here is another article with added information about the action of and results of deficits of vitamins and minerals. Richard Avery (talk) 07:06, 27 August 2014 (UTC)

Are fusors dangerous?

Say you have a fusor on your desk, and you switch it on, are the neutron emissions dangerous? If you are just sitting there without any shielding? 69.121.131.137 (talk) 00:00, 27 August 2014 (UTC)

Despite a very nice-looking Wikipedia article, and extensive interest in the popular-science and amateur "home-brew nuclear physics experimenter" community, these devices do not actually exist. The ones that "do exist" do not actually undergo nuclear fusion. If they did exist, and they emitted neutrons, the relevant article would be neutron radiation, § health hazards.

If you review the more reputable sources that our article cites, you will find, for example, some experimental apparatuses at the Fusion Research Laboratory of the University of Illinois at Urbana-Champaign. Reviewing the photos and descriptions on their website, if I were in the vicinity of their laboratory, I'd be much more worried about electrocution and electrical fires than neutron emissions. (The PI may be a tenured faculty member at a respectable engineering university, but something about his website makes me worry that basic fire-safety is an issue in his lab). Long before you get neutron emissions, you'd probably get hazardous x-ray emission via bremsstrahlung. ... And he knows it!

But you don't have to take my word for it (even though I've spent a lot of time in physics laboratories)! You can check out the Division of Research Safety website from the university (here is their radiation safety manual, including information on personal protective equipment, dosimetry, and procedures); or, in fact, just track down the equivalent health and safety office at any similar research facility. For example, Los Alamos National Laboratory has a very useful set of webpages that are available to the general public: Health & Safety at LANL. Physics laboratories that work with "uniquely hazardous materials" will usually have stringent guidelines and procedures to make sure that researchers and bystanders are not exposed to dangerous conditions.

(Apologies to the enthusiast amateur "home-brew nuclear physics experimenters" ... but what-ever you think you're building, it's just not that exciting to actual scientists. We, too, know how to create corona discharge by applying high voltage to ionize a low-pressure gas, creating a glowing plasma: it's called a fluorescent light bulb, and I have several hanging from the ceiling).

Nimur (talk) 01:02, 27 August 2014 (UTC)

The US Navy seems to think they exist, Nimur. http://www.nbcnews.com/science/science-news/low-cost-fusion-project-steps-out-shadows-looks-money-n130661 - So far, the Navy's spent US$12 million on the Polywell fusor.

Since there's some justifiable scepticism regarding NBC News's hot news flashes (they ARE the House of Exploding Pickups), here's the Park group ("EMC2, Inc.") paper on their latest results with the "Wiffle Ball" fusor design: http://arxiv.org/pdf/1406.0133v1.pdf

Getting back to the original poster's question, bremsstrahlung X-radiation is one danger, assuming the fusor operates at anywhere near peak efficiency and that deuterium or tritium are introduced into the fusor as "fuel". It's probably worth having a Geiger counter operating in the vicinity (ionization chamber meters aren't apt to be sensitive enough) if you're running a fusor with heavy hydrogen isotopes as "fuel".

A greater danger to the operator is electrostatic discharge or actual high-voltage/high-current leakage from the grids of the fusor, ESPECIALLY a home-brewed fusor (effective containment of high-voltage charges in grids with corners and curves in them being a black art ever since solid-state electronics replaced vacuum tubes for high-voltage applications). As to whether or not fusors exist, I can assure the reader they do, indeed, exist. Whether the energy released from an operating Farnsworth-Hirsch fusor ever approaches the power put INTO the device is a moot point, electrostatic inertial fusion does exist, the machines to produce it exist, and have existed for decades.

If mere presence in a physics lab conferred the sort of absolute knowledge required to deny the existence of fusors, janitors at those facilities would have the best jobs on Earth. Just think - hang out in a physics lab long enough and you can dispense with all those advanced math courses, blow off thesis committees... gangsta paradise! loupgarous (talk) 03:44, 27 August 2014 (UTC)

You are of course entitled to your own interpretation of a news article?

The Department of the Navy spends $12 million every hour just driving buses that move janitors to swab the decks of their ships and research labs. In the world of high-energy physics and Navy research programs, this is not a large amount of money. The cost to the average American taxpayer is a fraction of a penny per year. It would not be the first, nor the last, time that risky research was funded; nor the last time that a junk scientist managed to get funding for a pet project; nor the last time that the popular press misrepresented a science story to sell copy (or drive web traffic). Nimur (talk) 04:14, 27 August 2014 (UTC)

You're saying, then, that the WB grid fusors don't exist because the Navy didn't spend US $1.2 billion on it, which is a low-ball estimate of DoE expenditures on the National Ignition Facility, or the approximately US $18 billion which the thermonuclear fusion power research community has spent so far not getting fusion to work?

So far, by the most rational measure of "pathological science" (as defined by the Knolls Atomic Power Labs' Irving Langmuir), it's the thermonuclear fusion power effort that qualifies as "junk science" - barely detectable results, poorly reproducible results, and a highly-politicized environment which is the only environment in which it can survive. Unless you're hiding some evidence that thermonuclear fusion is, US$ 18 BILLION dollars later, even close to break-even, and I wish you'd produce it, if it does exist.

However, I did take the NBC News article with a grain of salt; published scientific journals such as the ARXIV article I linked have confirmed the comparative viability of the Polywell fusor for years. The return on investment of inertial electrostatic confinement fusion research like the Polywell fusor research is literally three orders of magnitude higher than that of thermonuclear fusion power research - read the .pdf I linked to and show me comparable progress toward break-even in thermonuclear fusion power. loupgarous (talk) 04:47, 27 August 2014 (UTC)

This isn't my area of expertise, but it does look very suspicious. The only people who use the word "fusor", as far as I can tell, are amateurs who build vacuum-tube devices that make pretty lights and think that they're somehow advancing the cause of fusion research by doing so. The word "fusor" does not appear in arXiv:1406.0133, which is about a polywell fusion device, which has its own article. I suspect the thing is never going to work, and the Navy probably shouldn't be funding it, but calling it a "polywell fusor" seems like an attempt by the fusor aficionados to pretend that they're real fusion researchers. I suspect ITER is not going to work either, but this is also irrelevant to whether we should have an article about "fusors". -- BenRG (talk) 05:44, 27 August 2014 (UTC)

If you had actually read the article on Polywell fusion devices, you'd know they're an evolutionary development of the Farnsworth-Hirsch fusor, one which was developed from considerable research by Dr. Robert Bussard undertaken over many years. So, the Polywell device is indeed a "fusor" - specifically, a development of the Farnsworth-Hirsch fusor.

I'd say, based solely on publishable results, what you refer to as "fusor aficionados" have as much right to describe themselves as "real fusion researchers" as the prime investigators connected with the National Ignition Facility. loupgarous (talk) 06:41, 27 August 2014 (UTC)

Since the disapointing Fleischmann–Pons experiment in 1989, most scientists consider claims of achieving Cold fusion dead and they now have a reputation as pathological science. 84.209.89.214 (talk) 13:08, 27 August 2014 (UTC)

In simple words please - Mitochondrial DNA

Does the Mitochondrial DNA has any significant impact on one's phenotype (Later edit clarification: I mean to everything except basic Metabolism)?... In my Biology or Biopsychology Textbook I haven't seen any mention for such impacts... thank you for this clarification!, Regards. Ben-Natan (talk) 03:52, 27 August 2014 (UTC)

Mitochondria do two main things - burn glucose and oxygen to make energy, and make proteins. Since every part of your observable appearance, traits and activity - your "phenotype" - depends on the action of proteins in your body (peptides, neurotransmitters and structural proteins) the simple answer is "yes".

It's an overly simplistic "yes," to be sure - the 37 genes in mitochondrial DNA are the tools used by nuclear DNA - the true "blueprint" of the body containing all the other genes - to make those proteins. Nuclear DNA has the information needed to say how the proteins are made by the mitochondria.

But if the mitochondrial DNA don't work correctly (a) cells stop using glucose and oxygen to make energy, or (b) transcription of information to make proteins doesn't work right and illness of one sort or another occurs. Nuclear DNA can be described as the WHY of cellular DNA, the information needed to make proteins correctly. Mitochondrial DNA is the HOW of cellular DNA, the 37 genes that are used to do the cell's business, and is just as essential to the phenotype of a healthy organism. loupgarous (talk) 04:05, 27 August 2014 (UTC)

I've added a clarification above: I know it plays a basic and vital role in Metabolism and making proteins, but is there anything extra to it in relation to the phenotype? I once heard of a researcher which tried to link Homosexuality in males to differences in mitochondrial DNA (Sounds to me like a desperate attempt to "prove" Homosexuality is genetic - a claim that seems to me to be disproved by Monozygotic twin research as can be hypothesized from this vid - 1:50). What is your opinion of this? Ben-Natan (talk) 05:33, 27 August 2014 (UTC)

The reference desk will not answer requests for opinion. Nimur (talk) 06:11, 27 August 2014 (UTC)

I believe I was clear in my explanation of how mitochondrial function impacts an organism's phenotype. The 37 genes of the mitochondrial DNA (in h. sapiens) control oxidative phosphorylation and protein synthesis, but the actual information which codes for synthesis for individual proteins is in the nuclear DNA, not the mitochondrial DNA. The phenotype's affected in very broad strokes when the mitochondrial DNA doesn't work right (or works more efficiently than is usual). Individual traits are, however, coded for in the nuclear DNA. loupgarous (talk) 06:18, 27 August 2014 (UTC)

mass &weight

spring balance measures weight of a body whereas common balance measure mass. if so does the readings shown by the two differ? — Preceding unsigned comment added by 117.218.119.166 (talk) 05:56, 27 August 2014 (UTC)

Sure! Think about how each scale would register if you were in an (accelerating) elevator.

For more fun, think about how each scale would register during your freefall stage if you took them skydiving. Nimur (talk) 06:10, 27 August 2014 (UTC)

Strictly speaking, a pan-balance measures mass (in kg or lb), and a spring-balance measures weight (in newtons, or pound-force, but displayed in kg or lb). Spring-balances are affected by the local gravitational force (it changes by a few percent), etc. CS Miller (talk) 08:45, 27 August 2014 (UTC)

What is meant precisely by "structure" in materials science?

The science of materials science is all about determining properties of a material from its structure. What is meant precisely by "structure"? 131.217.255.4 (talk) 06:46, 27 August 2014 (UTC)

The spatial arrangement of atoms/molecules in the solid material. Plasmic Physics (talk) 07:37, 27 August 2014 (UTC)

"Structure" (as defined in http://www.merriam-webster.com/dictionary/structure): "the way that something is built, arranged, or organized".

In materials science, "structure" means how materials are made at the molecular level, generally to find out how useful they are for a given job.

Metals and alloys, for example, are almost always crystalline in structure, with the outer electron shells determining how individual atoms in the crystal are organized. The shape memory phenomenon can, for example, cause there to be two or more different crystalline structures for a metal or alloy sample, depending on its temperature at any given time.

Metals also expand and contract at different rates and temperatures, so that when strips of two different metals are bonded together (in what's known as a "bimetallic strip") the difference in how each metal expands causes the strip to move in predictable ways from side to side - which is useful in analog thermostats.

Also, the hardness of an object can be determined by its crystalline structure. Carbon can be very slippery and soft in its "graphite" form, or very hard in its "diamond" form. That's a classic materials science issue.

Chemical compounds which are not crystals also are studied in materials science. Polymers (chains of various atoms or compounds) are studied in materials science to determine how suitable they are for a given application. Some polymers are very durable (they don't come apart easily when rubbed or struck), some (like graphite) slide apart very easily.

The motion of electrons through various materials is another branch of material science with numerous modern applications. Addition of tiny impurities in a silicon crystal, for example, cause electrons to flow under some conditions and not others - this class of materials is called "semiconductors," and is crucial in the manufacture of computers and many other electronic devices. Materials science research has turned up similar properties in titanium dioxide, which potentially is cheaper and less hazardous to work with than silicon and the toxic, flammable compounds of carbon and various metals used as dopants to make silicon a semiconductor.

Superconductors are combinations of metals and other elements which have little or no resistance to the flow of electrons at low temperatures, causing less power to be wasted in Joule heating of electrically-conductive wire over long distances, or in devices such as electrical motors which use very large lengths of wire to turn electrical current into motion. Inertia and gravitational force may change around some superconducting substances as the shape of local space changes.

Properties can be engineered into a given substance by changing its structure at very small levels of physical scale, in what is known as nanotechnology. Certain carbon nanostructures such as nanotubes can be used as structural materials to make very light, durable objects; some carbon nanostructures are being investigated for their usefulness as materials to replace lead and lithium in batteries.

These are only a few ways in which the structure of various substances make them more or less useful for given applications in engineering. Materials science is expanding as our knowledge of how different substances are made and behave under different circumstances grows. loupgarous (talk) 07:55, 27 August 2014 (UTC)

How can you control the structure of a material? 131.217.255.4 (talk) 09:15, 27 August 2014 (UTC)

Generally speaking, in Chemical engineering a desired material is obtained by Chemical synthesis or chemical separation, e.g. by Distillation. Then chemical analysis or structural analysis of the product may be done by Crystallography or Microscopy. 84.209.89.214 (talk) 12:27, 27 August 2014 (UTC)

Intellect of human

Is intellect of human being a product of natural selection in which human population is represented by different types of human?--Alex Sazonov (talk) 08:44, 27 August 2014 (UTC)

I think that, during the segregations of human population which is represented by different types of human the intellect of human is been revealed. And also, the mobility of the human type is always explained by the presence in its habitat of many types of human. The competition between the types is represented in the natural environment as the competition is not equal to each other types--Alex Sazonov (talk) 11:23, 27 August 2014 (UTC)

Evolutionary psychologists (see article) argue that much of human behavior is the output of psychological adaptations that evolved to solve recurrent problems in human ancestral environments. 84.209.89.214 (talk) 12:01, 27 August 2014 (UTC)

Is this yet another white-supremacy argument? ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:52, 27 August 2014 (UTC)

What type of human is more biologically stable a type of black human or type of white human, so that in what type of human always contains a preservative of the human genome?--Alex Sazonov (talk) 13:31, 27 August 2014 (UTC)