Wikipedia:Reference desk/Archives/Science/2007 April 13

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

April 13

Diesel Generator - External Fuel Tank?

I need a fast, safe, and efficient way to add an external fuel tank to a diesel generator for electric generation in remote, off-grid areas. I can't find a commercial product. What would I need? Tank? Pump? Hose? Does anybody have experience attaching, say, a 55-gallon drum, or does some standard technique exist?

Unfortunately, "just refilling the tank" is out of the question, since the generator will be at a remote site. Nimur 01:48, 13 April 2007 (UTC)

I have seen people use home heating fuel tanks in this application. (This makes sense, since home heating fuel is essentially identical to diesel fuel.) I think those tanks typically hold 150-200 gallons. It might not be too hard to find one, since they're being removed from many homes as they convert to gas heat. In fact, if you ask around, you might be able to find someone with an abandoned tank in their basement that they've been reluctant to shell out the money to have removed and hauled away, that they'd be more than happy to have you take off their hands. —Steve Summit (talk) 02:36, 13 April 2007 (UTC)

In the US, the standard "steel home heating oil tank" is 275 gallons. [1]

Atlant 13:46, 13 April 2007 (UTC)

In places where people burn fuel oil for heat, such large outside tanks are common. Here is a typical setup: [2]. StuRat 02:42, 13 April 2007 (UTC)

A diesel generator which is run unattended for a long time, as by attaching a large fuel tank, is apt to run low on lubricating oil resulting in destruction of the engine. For this reason it is advisable to have an oil level sensor to shut down the engine if the lubricating oil is low. Edison 20:46, 13 April 2007 (UTC)

Yikes. We're looking at upwards of two-week runs without maintenance or refueling. Any other suggestions? Nimur 04:31, 14 April 2007 (UTC)

I think a diesel generator is a bad idea if you need to leave it unattended for long periods. For off-grid use, solar power with batteries is often used. While solar cells are expensive, you don't have the expense of continually driving in diesel deliveries. If solar power is out for some reason (if you're in a foggy area, say), a windmill might also work. Another option would be to bring in fully charged batteries and return discharged batteries to a charging location on the grid. This would only be a good option if you have quite modest electricity requirements. What kind of power requirements does this facility have ? StuRat 05:00, 14 April 2007 (UTC)

Two weeks? Hm. Depending on the size and fuel consumption of your generator, you might need a pretty sizeable tank. Depending on the volume, site, and permanence of your installation – not to mention your jurisdiction – there may be rules and regulations that describe specific precautions and certifications an installation such as your might require. (Provisions for remote monitoring, secondary containment in case of a fuel leak, systems to report or respond to a fire, etc.) You might want to seek professional advice before setting up your system. TenOfAllTrades(talk) 05:07, 14 April 2007 (UTC)

All are valid points. We've used solar panels in the past for some of our remote sites, (usually coupled to a battery bank) but this usually requires a more complicated power supply (chargers, and conversion to appropriate voltage for our equipment). I think a windmill is out of the question, since they aren't readily available on short notice (among other things). If time was not an issue we could assemble a commercial system or develop an in-house solution, but the timeframe is "this week." We need to power a standard computer (PC) and a few other small peripherals. This equipment will need around 500 watts, so a 1kW generator seems to be big enough. As far as safety, it is generally acknowledged that we don't want anything that might leak fuel or otherwise be hazardous while unattended. Safety-tanks exist, but there aren't any local regulations that preclude a simple 55-gallon diesel drum. I'm more worried about weather and exposure; the fuel tank and lines will be located outdoors. Given the very short notice for this deployment, we are even considering 'manning' the site for two or three weeks, but that has its own costs in terms of manpower. Nimur 06:35, 14 April 2007 (UTC)

Outdoors? Really? That poses additional problems. Home heating fuel tanks are, as far as I know, intended to be installed *indoors* (contrary to what StuRat said).

Presumably the generator itself will be shielded from the weather; can't the fuel tank be also?

If you're worried about complying with applicable regulations, I get the impression that a recent one is indeed (as TenOfAllTrades suggested) a secondary containment system beneath the fuel tank in case it leaks. --141.154.50.248 07:15, 14 April 2007 (UTC)

Ophidian Peritonitis

Is there a reptilian version of Peritonitis or Coelemitis? Is this fast onset and inevitably fatal? —The preceding unsigned comment was added by 203.23.136.8 (talk) 03:22, 13 April 2007 (UTC).

Critical condition...?

What are the various designations a hospital or emergency room or doctor can give to indicate the condition of a patient and what do they mean? 71.100.6.150 03:24, 13 April 2007 (UTC)

Here's a few I've heard of (somebody else can give you they full details): stable, serious, critical, grave. StuRat 03:30, 13 April 2007 (UTC)

You forgot "dead". :) --TotoBaggins 05:57, 13 April 2007 (UTC)

That falls under "Condition: stable". :-) StuRat 06:20, 13 April 2007 (UTC)

... or grave. Rockpocket 06:23, 13 April 2007 (UTC)

See medical conditions. − Twas Now ( talk • contribs • e-mail ) 03:48, 13 April 2007 (UTC)

Some emergency departments will triage patients into green, amber and red. 194.176.105.39 08:03, 13 April 2007 (UTC)

Smaller Time/Distance

Why do things become so powerfull at smaller quantities, for example I read somewhere that gold can be explosive at the nanoscale level, also I'm not sure of the accuracy of this but if energy is released from a compacitor at a faster time then the watt value is higher than if it were realesed in a slower time value? Anyways My main question is, Why is smaller better?67.126.242.52 03:42, 13 April 2007 (UTC)

There's no one single answer. However, for an explanation of why a force acting over a short period of time can do more than a lower force over a proportionally longer period of time, see impact force (written by a rather brilliant author). :-) StuRat 03:50, 13 April 2007 (UTC)

Another reason is that for small particles there is a larger surface area per unit mass than for larger particles. So for example a chunk of iron a centimeter across will not do much in air, but if you have it in the form of fine 000 steel wool or iron filings it will burn when ignited. Since chemical reactions happen at a surface interface, if there is more surface, the reaction will be faster. An electrolytic capacitor uses the surface of the electrode to form a dielectric and store charge. So if the material is very fine, it has more surface, and can store more charge. see Supercapacitor. GB 04:12, 13 April 2007 (UTC)

For the capicitor, you are correct. Releasing its energy faster, accomplished by putting it in a circuit with less resistance, increases the power output. This is simply because power happens to equal the rate of energy transfer per unit time. Shorter time = more power, even if the energy is the same. So a capicitor releasing its energy slowly might make a magnesium filament go warm for a few seconds, but released over a small fraction of a second that filament will flare brightly and burn away (how some disposable camera flashes work). Someguy1221 08:55, 13 April 2007 (UTC)

Here is a thought experiment: Take a large wooden log - take a lighted match and try to set it on fire...basically, you can scorch the surface but it's not going to burst into flames. Now imagine a thin stick about the thickness of a finger - will that burn? Well, it might be hard to get it started - but you could just maybe get it lit with a match. What about a stick the thinkness of a matchstick? Yes - it will quite easily catch fire. Now how about thin strips of shredded newspaper? Those will burn really quickly...and if you blow a lot of sawdust into the air and light a match, you can cause an explosion! The smaller the object is, the more surface area it has for a given volume. This allows the combustion to start over a larger and larger area as the particles get smaller and smaller. SteveBaker 20:22, 13 April 2007 (UTC)

Wow thanks alot in fact I came up with another example, the fineness of rocketpropellant in solid core rockets. Thanks!

Coefficient of Relatedness verus Degrees of Separation

What is the difference between Coefficient of Relatedness and Degrees of Separation and can Degrees of Separation be used in the place of Coefficient of Relatedness for the same purpose? Clem 04:05, 13 April 2007 (UTC)

A Coefficient of relationship/relatedness is defined as "the probability that at a random locus, the alleles there will be identical by descent." In other words, it is a geneticist's way of numerically representing how close our "blood relations" are to us and each other. According to our article on the subject, a "degrees of separation" idea is that every "person is one "step" away from each person he or she knows and two "steps" away from each person who is known by one of the people he or she knows". The conclusion from this is that "everyone is no more than six "steps" away from each person on Earth." This is a societal/cultural theory and has no relation to genetic relatedness. Rockpocket 05:45, 13 April 2007 (UTC)

So you are saying that the concept of degrees of separation can not be adapted to the measure of relatedness? Clem 16:59, 13 April 2007 (UTC)

Yes. Degrees of seperation is a social construct. It relies on the fact we make friends and build social relationships, and has no bearing on genetic relatedness. You can have never met a sibling (say you were seperated from you family at birth) but that does not change your genetic relatedness. It would effect your "degree of seperation", though. Rockpocket 17:20, 13 April 2007 (UTC)

Why are parrots so damn messy when they eat?

Give my lovebird a handful of peanuts to snack on and after shelling the nut (okay, legume!), she'll crunch it in her bill and drop about two thirds of it onto the floor, then go straight onto shelling the next one, ignoring the fragments from then on. Yep, she's wasting food and making a mess of my carpet at the same time. Give her a piece of apple/orange/banana and she seems to shred and fling more than she eats. All the psittacines I've ever owned have been the same. Question: why are these birds so wasteful with their food? I can't imagine food supplies being so plentiful and regular in the wild that they can get away with doing that all the time (yet, according to the parrot documentaries I've watched, wild birds seem to eat in pretty much the same way)... --Kurt Shaped Box 10:22, 13 April 2007 (UTC)

I've noticed that also, but I guess they just can't pick it back up with thir beaks once they've droped it, though you'd think they grab it with their feet. They could just be being fussy as they know there is a plentiful supply of food. In the wild it may be different. Think outside the box 11:51, 13 April 2007 (UTC)

Part of the problem is that birds sometimes have different ideas of what constitutes food than we do. For example, my sister used to have a cockatoo, and if you fed it a tangerine, first it would peel the tangerine, then it it would peel all the flesh off the seeds and discard the flesh, then it would carefully (with beak and tongue) peel the outer covering off of the seed, then finally eat just the inner part of the seed. It seemed that all the rest, as far as she was concerned, was just "peeling". (But no, I can't explain the wasting half the peanuts part.) --Steve Summit (talk) 13:33, 13 April 2007 (UTC)

Since my answer includes speculation, I've included it here: [3]. StuRat 13:54, 13 April 2007 (UTC)

Perhaps since a beak has no lips, if the seed is too big to properly fit in the beak, anything that is outside the beak when the bird bites has to drop down.-Czmtzc 15:05, 13 April 2007 (UTC)

Yes, but that doesn't explain why the bird doesn't go after the dropped morsels. Parrots are incredibly dexterous with their beaks - it's not a matter of not being able to pick them up again (they can pick up and manipulate the tiniest of objects if they're interested in them - my lovebird likes to break toothpicks). A friend of mine has a macaw that likes walnuts and brazils - he'll shell the thing (holding it in his foot), take a couple of bites of the nut and drop the rest. Then he'll grab another nut and repeat. --Kurt Shaped Box 16:27, 13 April 2007 (UTC)

I'd say it's just like people behave. Would you pick up food off the floor and eat it if you had plenty of food left on the table ? Probably not, because it could be contaminated. But, if you were starving and out of food, that would change things around. As for intentionally dropping parts, I go back to my earlier speculation. StuRat 18:05, 13 April 2007 (UTC)

And you might want to try being a lot more conservative in your feeding at least long enough to determine it this will trigger a behavior change. People in deprived situations have been known to eat cockroaches even if only in (not at) the movies. Clem 18:30, 13 April 2007 (UTC)

First, parrots just enjoy taking things apart. One of my birds often shells almonds and once he gets it open, drops the nut. He's not that fond of almonds, just interested in the taking apart (as opposed to pecans, which he loves and doesn't waste a bit of). They enjoy shredding wood, too, and it's not like they think it's edible (and see http://www.youtube.com/watch?v=Ozd3xAv-cZM ). Parrots also enjoy dropping things. They love the game where they drop it and you pick it up (and they drop it, and you pick it up, and they drop it... see http://www.youtube.com/watch?v=REFkDP7r7Jw ), but also enjoy dropping things in general (see http://www.youtube.com/watch?v=Hzh70XBxfB0 ). When we feed our birds broccoli or cauliflower, we have to cut it up fairly small before they'll eat it. They think it's more fun to fling big pieces. Small pieces don't make much noise when they hit the cage floor, so you may as well eat them.

Second, they often have an overabundance of food - not only in captivity but also in the wild. When a large fruit tree ripens, there may be more food than they can eat, and it won't last long. They may as well eat just the choicest bits. They're less picky when food is scarce and they're hungry.

Ours do not mind picking food off the floor. They often drop choice bits on the floor and climb down to get them later. (We think it's at least partly in hopes that we'll notice that they're out of good stuff and give them more. If it didn't work, no sense wasting the food).Brucemoko (talk) 16:11, 21 May 2009 (UTC)

Tunafish - cooked?

Hi, is tuna fish cooked when it's in a can? If not, is it a kind of sushi. It's stored in sunflower oil or brine so it could be uncooked but it seems more likely that it's cooked! Been bugging me for a while. Thanks for any help! JoshHolloway 13:20, 13 April 2007 (UTC)

Yes, it is cooked. Most tuna that you'll find at the grocery store has actually been cooked twice—once before canning, and again by the heat and pressure during the canning process. It's also possible to buy (or make) canned tuna that is cooked only once, during the canning process. This product tends to be more expensive, may result in more intense flavours (which may or may not be desirable) and retains more omega-3 fatty acids (a good thing). Explanatory link. —The preceding unsigned comment was added by TenOfAllTrades (talk • contribs) 13:47, 13 April 2007 (UTC).

(after EC)Technically, you'd mean sashimi, not sushi, but what's important here is that not only is the tuna that's in the can cooked, it is cooked while it's in the can. Here is a link to a description of tuna processing. Another more technical description. This method seems to be called "retort cooking," our article for pressure cooking mentions that "In the food industry, pressure cookers are often referred to as retorts." So, put away the seaweed, rice and wasabi. --LarryMac 13:49, 13 April 2007 (UTC)

Thanks to both of you :). JoshHolloway 18:55, 13 April 2007 (UTC)

As canned tuna fish has got a long shelf life, it has to be cooked, else Clostridium botulinum might kill you. Icek 01:57, 14 April 2007 (UTC)

tv vs monitor

Hello. I've found that buying a LCD computer monitor (with or without a built in TV tuner) is literally hundreds of currency units (£) less than buying a LCD TV. In addition they are a higher resolution (typically 1280x1024) than the TV equivalent (often only 1024x768). The only difference I can see is that the speakers are not very good in the monitor (but not much worse than the TV speakers) - Is there some reason why adding a TV tuner to a flat panel display seems to add hundreds to the price (in the UK) - am I missing some crucial functional difference.?87.102.84.170 16:02, 13 April 2007 (UTC)

The tv usually has a larger diameter. – b_jonas 16:16, 13 April 2007 (UTC)

Agreed, if you try to get a 25 inch LCD computer monitor, it is even more expensive than a 25 inch LCD TV. StuRat 16:22, 13 April 2007 (UTC)

I was comparing same sizes - but your answers show my experience must be a purely local phenonoma. Thanks.87.102.84.170 17:24, 13 April 2007 (UTC)

Another Radiation Question

Yep here i go again. i think some of this should be included in the articles anyways. How much of your body has to be exposed to Leathal radiation? in other words will radiation be lethal if it only your finger is exposed to the leathal dose? will your finger be the only thing to fall off? <(maybe a bit to extream there) and can you save yourself if you cut your finger off? thanks again guys User:Maverick423If It Looks Good • Nuke It 16:03, 13 April 2007 (UTC)

Generally something critical has to be exposed for you to die of radiation poisoning. This typically would include the lungs (death from asphyxiation), digestive tract (death from diarrhea), skin (death from dehydration), and immune system (death from disease). However, as cancer can metastasize from one area to another, even a strong dosage on a finger could spread cancer. Amputating the finger would eliminate this risk. However, you might not get it in time, and some cancer cells could get to the rest of the body. Of course, if your finger was injected with a highly radioactive isotope in liquid form, it would spread to the rest of the body within a few minutes, via the circulatory system. StuRat 16:16, 13 April 2007 (UTC)

Sweet thanks much!! User:Maverick423*If It Looks Good • Nuke It 16:35, 13 April 2007 (UTC)

You're quite welcome. StuRat 18:00, 13 April 2007 (UTC)

It should be noted that you are talking about two different ways of dying from radiation here. Generally speaking you get radiation sickness from highly radioactive, short-half-life isotopes, while cancer is more often from small bits of weekly radiating, long-half-life particles which through one pathway or another get into your lungs, bones, etc. and then sit there and radiate you with alpha particles, etc. They should not be mixed up, they are quite different types of hazards. --24.147.86.187 18:59, 13 April 2007 (UTC)

As the previous comment points out, there are lots of kinds of radiation (some kinds lethal, some not), and I'm no expert on any of them, but for a sobering tale, read about what happened to Louis Slotin. --Steve Summit (talk) 19:01, 13 April 2007 (UTC)

The questioner did not ask about injection of radioactive substances into the blood stream, but about exposure of the a finger to alpha, beta or gamma radiaton. I suspect the correct answer would be cancer of the exposed parts. So cutting off your finger before the cancer has time to spread may be a good idea. (I am not, nor have ever been, a doctor so this does not constitute medical advice) —The preceding unsigned comment was added by 88.110.125.229 (talk) 19:02, 13 April 2007 (UTC).

For a real life example, consider that breast tumors are sometimes treated with radiation directed to that body part alone if a small malignant tumor has been removed. What are the effects to the rest of the body? Nausea? Hair loss? Nothing? Also read about Clarence Madison Dally who was an early tester of X-Ray machines when nothing was known about radiation hazards. He died a horrible death after progressive amputations. There is more detail at [4] and a contemporary article at [5]. Edison 19:38, 13 April 2007 (UTC)

Here is an interesting ref on radiation standards from the beginning to now and case histories of injuries: [6] Edison 20:24, 13 April 2007 (UTC)

Wow that article acctually freaked me out a bit. Stuff like that just reminds of how weak and fragile the human body is. User:Maverick423 If It Looks Good Nuke It 20:29, 13 April 2007 (UTC)

Cylindrical mirror

What would it look like if a person were inside of a cylindrical mirror? What would the image look like? Dismas|^(talk) 17:17, 13 April 2007 (UTC)

If, by your question, you mean what would the person inside the cylinder see, then he/she would see a skinny version of him/herself, assuming that the cylinder isn`t HUGE! Please correct me if I`m wrong. 64.230.233.196 20:01, 13 April 2007 (UTC)Dave

Upon reconsideration, I believe I was exactly wrong. The person would view a 'wider' version of him/herself. I might add, right-side-up! Sorry for any confusion. 64.230.233.196 20:28, 13 April 2007 (UTC) Dave

But what about the reflections? --Wirbelwindヴィルヴェルヴィント (talk) 06:20, 14 April 2007 (UTC)

The reflection in the part of the mirror behind them would be behind them, so the light would have to travel through the person looking to create a reflection of a reflection, however the light could be reflected around them lots of times, which wouls make the reflections further around fade, and they would overlap too. I think the only realisic way to find out would be to try it.

Great, anybody got any cylindrical mirrors that I can get into?  :-) Dismas|^(talk) 19:22, 15 April 2007 (UTC)

The image seen from near the center of a cylindrical mirror would be highly astigmatic and therefore impossible to focus on. Why not consider the similar but more symmetric question of what you see if you put your head inside a hollow spherical mirror? That question has the advantage that Dismas may find a real concave spherical mirror easily to do the experiment (not a whole sphere, but enough of one to get the idea): bathroom shaving mirrors are often concave spherical on one side.

If the pupil of your eye is at the exact center of the sphere, you (that eye) will see its own pupil reflected in all directions, as a huge dark sphere. Actually, the mirror throws an image of the pupil back into the pupil. In general, if there is an object near the center of the sphere, the mirror will create a real image of that object (inverted left-to-right, up-to-down and back-to-front), at the same distance on the opposite side of the center of the sphere. Thus if your head is at the center, there will be an image of your head that roughly coincides with your actual head, except for being upside down etc. Unfortunately you can't focus on something that close, so you can't see this image. (Also, it can't quite form, because your head is in the way...) To see the image, you'd have to move your head back behind the center of the sphere; you would then see an upside-down (and slightly demagnified) image of your head hanging in the air in front of you, the same distance on the opposite side of the center. As you move forther back, the image moves further away and gets somewhat smaller. If you instead move forward from the center, your image will move back behind you and be even harder to focus on, until you get close to a point halfway from the center to the mirror surface (called the "focus"), at which point the real image ends up an infinite distance in back of you, and gets reincarnated as a virtual, non-inverted, magnified image an infinite distance in front of you. That one you can see! As you move even closer to the mirror, this virtual image moves closer and gets less magnified until, when your nose is up against the glass, it looks much like your image in any normal, flat mirror (and of course has its nose against the glass!) Shaving mirrors are used in the range where your head is between the focus and the glass, so that they produce a moderately magnified non-inverted image to help you avoid slicing your neck open with your razor. --mglg_(talk) 21:35, 15 April 2007 (UTC)

Coefficient of Relatedness envisioned

Can the concept of Coefficient of Relatedness be correctly envisioned by the situation of the probability of a news photographer who goes to a random location and while standing in the exact same spot as previous photographers will take the identical photograph? Clem 17:23, 13 April 2007 (UTC)

I suppose if it is an often photographed spot, and we are talking about the coefficient of relatedness to Dannielynn Stern, then yes, the probability is similar. In normal circumstances, no. Can you explain why you think they are related, and I might be able to give you a better response? − Twas Now ( talk • contribs • e-mail ) 22:28, 13 April 2007 (UTC)

Question has absolutely nothing to do whatsoever with Dannie Lynn Birkhead or her real father Larry Birkhead except perhaps for the twist that is in your mind. Clem 23:57, 13 April 2007 (UTC)

In fact now that I think about it the whole case of Smith vs Marshall will probably be thrown out now on the grounds of attempted fraud. Clem 00:08, 14 April 2007 (UTC)

can safety

Is it safe to put a can of any water based food product such as vegetables or beans, etc. into a deep pan of water and bring the water to a boil for several (15) minutes without the can exploding? Nebraska Bob 17:46, 13 April 2007 (UTC)

Definitely not. At best, you can put the can in hot tap water, but you don't want to get anywhere near boiling, or the can might explode. I'm guilty of having done that in college when I didn't want any dishes to clean. StuRat 17:58, 13 April 2007 (UTC)

Was th entire can submerged well below the water level? Nebraska Bob 18:23, 13 April 2007 (UTC)

Yes, and I typically had to replace the hot tap water a few times and wait several hours before the can contents got hot. One benefit for the absent-minded was that it wouldn't burn if you forgot about it, unlike stove top cooking. StuRat 20:25, 13 April 2007 (UTC)

I'm not sure what you're trying to acheive but if you just want to heat the can of food so that it can be eaten without dirtying the pot, you could put a few holes in the top of the can and then boil it with the top of the can above the water's surface. Dismas|^(talk) 18:52, 13 April 2007 (UTC)

If you pierce the can thare will be no danger of explosion. However, the food in the can might ooze out of the holes. —The preceding unsigned comment was added by 88.110.125.229 (talk) 18:56, 13 April 2007 (UTC).

After a few minutes in boiling water, the water in a container inside the boiling pot will also start to boil and the pressure will increase creating an explosion hazard. Even if a hole is punched in the lid of the can, all it takes is for a bit of the contents to plug the hole during the vigorous boiling, and the explosion hazard is back. This has even happened in pressure cookers when cabbage blocks the pressure vent, but fortunately there was a fuseplug which blew resulting in a cabbage spewed ceiling rather than shrapnel. This sounds like a good project for Mythbusters. Edison 19:35, 13 April 2007 (UTC)

Maybe but I thought all cans had lots or built in expansion ripples (in addition to the air gap inside) enough to prevent an explosion so that you could heat or even cook the contents in boiling water. 71.100.4.87 19:55, 13 April 2007 (UTC)

Definitely not - the volume of steam produced by even a tiny amount of water boiling is immense! No small ripples or air gaps could possibly provide enough space for the steam produced by even 1 cc of water. This is exceedingly dangerous - don't do it!! SteveBaker 20:13, 13 April 2007 (UTC)

Agreed. StuRat 20:25, 13 April 2007 (UTC)

Take a look at this: Dulce de Leche. Clem 20:01, 13 April 2007 (UTC)

OK exploding soup (at lowish velocity) in the eye can be a bit painful, but not as painful as exploding shrapnel at high velocity. —The preceding unsigned comment was added by 88.110.125.229 (talk) 20:03, 13 April 2007 (UTC).

Ok first of all StuRat OMG but hey it happened to me too =) (no one likes dirty dishes) secondly, there is one canned food that can acctually be boiled. its that Condensed milk the sweet one that is, cooking it in boiling water for a hour or so (more if you want) will cook the milk inside to create a delicacy known here in deep south texas as Cajeta It is very tasty and goes great with toast. User:Maverick423 If It Looks Good Nuke It 20:37, 13 April 2007 (UTC)

That sounds like the Dulce de Leche link above. Just because it hasn't exploded yet doesn't mean that it never will. StuRat 21:13, 13 April 2007 (UTC)

(edit conflict)

yea actually now that you point at it they are one in the same. they just have diffent names =) and i have seen hundreds of cans boiled like this yet not one has exploded. it might be something inside the cans that prevents such explosions? User:Maverick423 If It Looks Good Nuke It 21:50, 13 April 2007 (UTC)

I'm speaking off the top of my double boiler here, but perhaps the sugar or the concentrated milk protein raise the boiling point? Remember that in a water bath like that, the contents wouldn't ever get hotter than the boiling point of the water. Anchoress 00:04, 14 April 2007 (UTC)

Et voila! Anchoress 01:11, 14 April 2007 (UTC)

That makes sense, but it still seems dangerous, to me. If you forget about it, all the water boils off, and the can heats by conduction with the bottom of the pan, the heat could easily cause the can to boil and explode. Personally, I'd can the whole idea. StuRat 01:23, 14 April 2007 (UTC)

Yeah, I wouldn't do it. But what I don't understand is, if the fluid isn't actually evaporating, how does it get thicker? Anchoress 01:28, 14 April 2007 (UTC)

It sounds like a Maillard reaction. StuRat 01:34, 14 April 2007 (UTC)

I am aware of Hydrostatic pressure in which case there is no expansion room (air gap) left inside the can so how much expansion room would be required to accommodate a temperature of say 110 degrees Celsius? If its possible to do then lets petition the food canning industry to add ripples or whatever to help us save energy by not having to use all that hot water for cleaning dishes! 71.100.4.87 21:46, 13 April 2007 (UTC)

Just to complicate things, the can itself will expand with heat. Probably not as much as the liquid inside, though, even if it doesn't boil. --Anon, April 14, 02:52 (UTC).

heh i love 71's thinking however adding ripples that expand with heat will be more costly thus increasing the prices of a simple can of food. heck it might be enough to increase a 50 cent can to $1. im sorry to say but i would rather do dishes then pay more XD User:Maverick423 If It Looks Good Nuke It 22:35, 13 April 2007 (UTC)

I wouldn't worry about the price going up. In fact it would probably come down. How you ask? Simple. The on going manufacturing trend is to lower the price while either reducing the size or watering down the product. The only exception I have seen in the last 3 months is Wal-Mart Great Value brand Apple juice which increased the container size but did not increase the price or water down the product. Clem 23:49, 13 April 2007 (UTC)

According to this link [7] it is okay to boil cans for 10 minutes to disinfect them, provided they are not carbonated beverages. Also, in terms of the boiling condensed milk to make caramel thing, there are numerous suggestions you can find google (e.g. [8] & [9]) that it's okay, provided you don't let the water dry up (i.e. provided the can doesn't get above the the boiling point). Of course, there are anecdotal at best so I wouldn't say they are extremely trustworthy Nil Einne 09:28, 14 April 2007 (UTC)

I boil condensed milk fairly frequently, and have never yet had a can explode. I usually cook four cans at a time, in a big soup pot. For safety, I bring the water to a boil, but then turn it down to a simmer; and leave it on the stove for four hours but set the kitchen timer to remind me to top up the water every half an hour, to ensure it never reaches the top of the can. Then let the cans cool in the water - I don't take them out until I can put my bare hand in. The fudge is delicious - the longer you cook it, the darker it is. I wouldn't recommend trying it for anything else, though - I've seen soup cans explode (in a pot in an open campfire), without the water reaching the top of the can. But the condensed milk fudge? Perfectly safe if you're careful. Natgoo 18:46, 15 April 2007 (UTC)

urethra

Whenever I see diagrams of the male urethra, there's always a bulge at the piss hole end. What's the name and use of that bulge? —The preceding unsigned comment was added by Bonghits4muhammad (talk • contribs) 19:59, 13 April 2007 (UTC).

A gasket. Stops sperm from leaking out. Also prevents slipping out like the expanded end of a hammer or knife handle. Clem 20:06, 13 April 2007 (UTC)

See meatus. As to the porpoise, who knows? It appears to be called the lacuna magna

Clem?...By 'slipping out', do you mean, errr, 'post-penile drip'? 64.230.233.196 20:21, 13 April 2007 (UTC) Dave

Hmm, I rather think that Clem and Dave are misinterpreting the Question. The Question is about the increased diameter of the urethra (not the knob end) near the urethral meatus. This area is called the 'lacuna magna' (on which we dont have an article).

The purpose of increased diameter of the penis (knob end) has been postulated to be to remove semen from the vagina deposited by other males. This is yet to be comfirmed.

If so, vestigal by now then isn't it? But if the lacuna magna was to "suck it up" then what happens when ejaculation occurs? It goes right back. [Mαc Δαvιs] (How's my driving?)  ❖ 22:04, 13 April 2007 (UTC)

Why so? I suppose it depends what sort of woman you are having sex with. Rockpocket 00:46, 14 April 2007 (UTC)

I didn`t misinterpret the question. I was merely questioning Clem`s answer. I wanted to know what Clem meant by 'slipping out'. Interesting all the same. 64.230.233.196 22:45, 13 April 2007 (UTC) Dave

I've never heard of the "lacuna magna". The dilatation of the urethra in the glans penis is most commonly called the navicular fossa. --David Iberri (talk) 06:21, 14 April 2007 (UTC)

See here [10]. Do you have Gray's anatomy?

Thanks, but that link only exists because I just created the redirect. ;-) No, I don't have Gray's Anatomy, but I did notice "lacuna magna" in the Gray's image here. Still, it's more commonly called the navicular fossa. --David Iberri (talk) 18:04, 14 April 2007 (UTC)

It would appear lacuna magna is not a synonym for the navicular fossa. Also called the valve of Guerin, it "is a congenital diverticulum embryologically arising from the dorsal aspect of the fossa navicularis." [11] A "common embryologic remnant" in males, [12] it can result in "spotting of blood per urethram, hematuria and episodic painful voiding in boys" [13] Rockpocket 18:20, 14 April 2007 (UTC)

Nice work. The Gray's label threw me. Lacuna magna now has its own page. Cheers, David Iberri (talk) 15:22, 16 April 2007 (UTC)

The Skinny Wine?

From wine:

The color of wine is not determined by the juice of the grape, which is almost always clear, but rather by the presence or absence of the grape skin during fermentation. ... Red wine is made from red (or black) grapes, but its red color is bestowed by a process called maceration, whereby the skin is left in contact with the juice during fermentation. ...

Can a red wine be made with extra skin? For example, can I:

• Press the grapes lightly, use the clear juice to make white wine and use the remaining juice to make red wine; or
• Add extra grape skins into the juice to make red wine; or
• Add skins from other breeds of grapes?
• Recycle skins from the last batch of wine?

Can I make extra bitter red wines with much skin and just a little juice? Can I use other plants' skins? -- Toytoy 23:21, 13 April 2007 (UTC)

I don't buy that quote, because unfermented grape juice also comes in red (from red grapes), blue (from blue grapes), and white (from white/green grapes). StuRat 23:58, 13 April 2007 (UTC)

I did a vinyard tour in California a few years ago - and they do indeed make white and blush wines by crushing red grapes and pulling the skins out as rapidly as possible. For red wines they leave the skins in longer. Other regions make white wines from white grapes - and rose by mixing the grapes before crushing or by mixing the wine sometime later in the process. Check out Zinfandel for example - which explains that these are red-skinned grapes - yet White Zinfandel is made from them. SteveBaker 01:41, 14 April 2007 (UTC)

(after edit conflict) It is, nevertheless, correct. White Zinfandel is made from the 'black' (red) Zinfandel grape; it is pale pink in colour because it is allowed only a limited amount of time in contact with the coloured grapeskins. See the White Zin article and also our article on Rosé wines for more details. (Incidentally, the article on Rosés also addresses a number of the original poster's questions.)

Champagne (the French sparkling wine from the region of the same name) is almost exclusively made from three varieties of grapes. Two – Pinot Noir and Pinot Meunier – are black grapes, but Champagne is most assuredly not a red wine. A number of Champagne houses produce a Champagne from only black grapes; a blanc de noirs.

Vitis vinifera grapes all give pale, usually yellowish juice. Other grape species and cultivars – ones not typically used for winemaking – may have coloured flesh; the Concord grape (probably Vitis labrusca) is one example. TenOfAllTrades(talk) 01:46, 14 April 2007 (UTC)

But the quote seems to be saying that grape skins must be left in the juice, while it ferments, to impart their color into the wine. How then, can unfermented grape juice contain the color of the grape skins ? StuRat 02:07, 14 April 2007 (UTC)

It's in the last paragraph of my response. The grape species used for unfermented beverage production are not the same species of grape used for winemaking. Grapes used for juice represent a number of different species, some of which have vividly coloured juice. Grapes conventionally used for winemaking (almost exclusively of the species Vitis vinifera) have uncoloured juice and a variety of different colours of skin; red wines get their colour by leaching it from the grapeskins. TenOfAllTrades(talk) 02:40, 14 April 2007 (UTC)

However unlikely, can I brew wine using supermarket grape juice and natural yeast? Can I add extra skin to the juice to make the wine stronger in color and flavor? -- Toytoy 04:00, 14 April 2007 (UTC)

Let me answer the question by myself: see must, pomace and pomace wine. -- Toytoy 04:16, 14 April 2007 (UTC)

(after edit conflict which makes part of my reply redundant...) You can brew something that way. The yeast will ferment the sugars in the juice into alcohol. Whether it resembles wine in any way, shape, or form is anyone's guess. Note that the grape varieties used to make juice or sold as whole grapes at your supermarket are very unlikely (as I discussed above) to be the same species of grape as those used normally to make wine. Adding extra skins may also make the wine undesirably tannic in flavour.

You may also be interested in our articles on pomace wine (wine made from the leftovers from winemaking) and pruno: an alcoholic beverage made from fruits and juices, most often in prisons. TenOfAllTrades(talk) 04:25, 14 April 2007 (UTC)

Grapes that grow in vineyards have grains that are much smaller and have much thinker skins than those found in grocery stores. In fact, in the production of quality wine, it is undesirable for grains to contain much water at all. As illustrated by Sauternes, grapes infected with noble rot are most priced, because the fungus absorbes much of the water in the grains, leaving a rich and concentrated nectar, the prime ingredient to a grand cru. This is also why rain late in the growing season can ruin a potentially great vintage (as it happened in Bordeaux in 1992). The vines just suck the rain water in, diluting the grape juice. As an anecdote, Château Pétrus once actually covered their entire vineyard with cellophane sheets that prevented rain water from reaching the ground.--JLdesAlpins 14:10, 14 April 2007 (UTC)

It's apparent (or is that transparent) to me that the water would need to go somewhere. They would clearly also need to set up a trough system for drainage. StuRat 14:45, 14 April 2007 (UTC)

Feeding before training

I was wondering if it is good for your muscles to train after eating since you have less blood supply to them you should presumably build more respiratory pigments to compensate. Tell me if I missed anything. —The preceding unsigned comment was added by Bastard Soap (talk • contribs) 23:44, 13 April 2007 (UTC).

"Respiratory pigments" ? Does that mean red blood cells ? StuRat 23:55, 13 April 2007 (UTC)

Not quite. The respiratory pigment in humans is hemoglobin, which makes up most of the adult red blood cell. I confess I don't quite understand the original question. - Nunh-huh 02:45, 14 April 2007 (UTC)

Is it possible to increase the amount of hemoglobin without increasing the number of red blood cells ? StuRat 03:30, 14 April 2007 (UTC)

Well, yes, some diseases do that, but exercise shouldn't. Our coverage on red blood cell indices is a little fragmented: probably the most applicable article we have is mean corpuscular hemoglobin- Nunh-huh 03:40, 14 April 2007 (UTC)

Ok, so let me re-phrase the question. As far as I know when you experience continued insufficient oxygen supply to your tissues the body increases the ammounts of myoglobin in muscles and haemoglobin (increasing number of erythrocytes), and after feeding a lot of blood is occupied with digestion, so presumably you would have a greater oxygen dept. The question is if it is good for your ammount of respiratory pigment (and for general health) to train after lunch?Bastard Soap 08:06, 14 April 2007 (UTC)

The level of hypoxia you are able to induce in your muscles is directly related to the amount of exercise you are able to force yourselt to do (read: number of reps), and eating a meal isn't going to appreciably increase that level of hypoxia: your body would decrease the blood flow to the gut if needed to increase it to your muscle, though you likely have plenty of oxygen reserve to do both. - Nunh-huh 08:39, 14 April 2007 (UTC)

Are there any good methods to increase hypoxia?Bastard Soap 11:00, 14 April 2007 (UTC)

I think I understand now, you're trying to get an advantage over other athletes, like people get by taking epo, without it being detectable in a test. Do I have it right ? StuRat 14:38, 14 April 2007 (UTC)

Athletes do this by using altitude simulation tents. --NorwegianBlue ^talk 20:08, 14 April 2007 (UTC)

I don't intend to do this for any competition or anything, just looking for something healthy with can augment my training.Bastard Soap 17:22, 15 April 2007 (UTC)

Or they can take some of your erythrocytes out, then you would create more to make up for the loss, then they can put your blood back in just before the race.

Eating just before doing anything is a bad idea as the food sloshes around inside you.

Hmm..sloshes..exactly what do you mean by that? I searched a bit on those hypoxic tents but they're a couple of thousands, can't do anything with a thinner budget?Bastard Soap 20:36, 16 April 2007 (UTC)