Wikipedia:Reference desk/Archives/Science/2011 March 20: Difference between revisions
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::::Origins aside, many kiwis are probably familiar with the promotion of red meat (sometimes under that name) by Beef & Lamb NZ [http://www.beeflambnz.co.nz] some of which are available here [http://www.beeflambnz.co.nz/index.pl?page=campaigns&m=391] [[User:Nil Einne|Nil Einne]] ([[User talk:Nil Einne|talk]]) 08:30, 21 March 2011 (UTC) |
::::Origins aside, many kiwis are probably familiar with the promotion of red meat (sometimes under that name) by Beef & Lamb NZ [http://www.beeflambnz.co.nz] some of which are available here [http://www.beeflambnz.co.nz/index.pl?page=campaigns&m=391] [[User:Nil Einne|Nil Einne]] ([[User talk:Nil Einne|talk]]) 08:30, 21 March 2011 (UTC) |
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::::@90.201/Jayron - I was under the same impression as Jayron regarding the origin of the term, but it occurs to me know that I have absolutely no reference to back that up. Do either of you have anything to offer in terms of support? I did some Googling, but didn't get anything much at all and our [[red meat|article]] doesn't really cover it. [[User:Matt Deres|Matt Deres]] ([[User talk:Matt Deres|talk]]) 01:40, 22 March 2011 (UTC) |
::::@90.201/Jayron - I was under the same impression as Jayron regarding the origin of the term, but it occurs to me know that I have absolutely no reference to back that up. Do either of you have anything to offer in terms of support? I did some Googling, but didn't get anything much at all and our [[red meat|article]] doesn't really cover it. [[User:Matt Deres|Matt Deres]] ([[User talk:Matt Deres|talk]]) 01:40, 22 March 2011 (UTC) |
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:::::The (1933) OED has two citations: the first, purely descriptive one is from M Donovan's ''Domestic Economy Vol II'' of 1837; the second is from P Manson's ''Tropical Diseases'' of 1898 and advises avoiding it (though presumably in a particular context). Beyond that I can only say that I (being in my 50s) have always been familiar with the term , and have only encountered suggestions that red meat might be unhealthy within, say, the last 15. Personally I take such claims with a large pinch of salt. (Only a metaphorical one, before we start down that road as well!) {The poster formerly known as 87.81.230.195}[[Special:Contributions/90.201.110.155|90.201.110.155]] ([[User talk:90.201.110.155|talk]]) 18:32, 24 March 2011 (UTC) |
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::Nutritionally, duck is definite more chicken than beef. The biggest problem with red meat is the mammalian hemoglobins--not the fats. [[User:Imagine Reason|Imagine Reason]] ([[User talk:Imagine Reason|talk]]) 11:21, 22 March 2011 (UTC) |
::Nutritionally, duck is definite more chicken than beef. The biggest problem with red meat is the mammalian hemoglobins--not the fats. [[User:Imagine Reason|Imagine Reason]] ([[User talk:Imagine Reason|talk]]) 11:21, 22 March 2011 (UTC) |
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:::What, exactly, is wrong about those mammalian hemoglobins? [[Special:Contributions/93.132.164.231|93.132.164.231]] ([[User talk:93.132.164.231|talk]]) 21:38, 22 March 2011 (UTC) |
:::What, exactly, is wrong about those mammalian hemoglobins? [[Special:Contributions/93.132.164.231|93.132.164.231]] ([[User talk:93.132.164.231|talk]]) 21:38, 22 March 2011 (UTC) |
Revision as of 18:32, 24 March 2011
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March 20
What would it take to invent a vacuum-operated toilet?
If we don't have enough time in the day to even answer the call of nature the normal way, could there be a vacuum toilet that sucks out all the bodily wastes so that we wouldn't have to spend as much effort pushing it out ourselves? How much faster could this process be if this was vacuum assisted? Would it do a better job than normal? Would it be able to suck out more waste than we can push out?
So how come there hasn't been a vacuum-operated toilet yet? --70.179.169.115 (talk) 02:33, 20 March 2011 (UTC)
- Astronauts use something similar, but you don't want so much suction that it can do damage. A minimal vacuum, just to suck the stench out, might work. StuRat (talk) 02:40, 20 March 2011 (UTC)
- Before anyone goes through the effort, can you show that it's even necessary? Who says that we don't have enough time in the day to go the normal way? Dismas|(talk) 03:08, 20 March 2011 (UTC)
- It wouldn't work as you expect. To avoid disgusting mental images, think of this scenario: You have a plastic bag full of liquid. It has a narrow rubber hose so the liquid can drip out. To get it out, you squeeze the bag. That is how it should work. To make it faster, you suck the liquid out. The result is that the rubber hose collapses. Sucking harder makes the rubber hose squeeze tight. Nothing come out. The solution is to shove a stiff straw up the rubber hose to keep it from collapsing. Then, you have no problem sucking the liquid out (that's how those juice bags that kids drink work - they use a hard straw, not a flimsy little tube). So, your vacuum would actual keep you from evacuating your bladder or bowels instead of making it faster. The solution would be a stiff tube shoved in one hole or the other before attaching the vacuum - which will likely take longer than just going to the bathroom. So, what do people do? That's why they make magazine racks for bathrooms. Some people have televisions in their bathroom. Whatever you need to do, find something that allows you to sit for a while. -- kainaw™ 04:16, 20 March 2011 (UTC)
- Well then Kainaw, I guess I'll have to resort to a liquid-based "straw" called the Washlet. I wonder if that's what they have in the space stations. --70.179.169.115 (talk) 08:09, 20 March 2011 (UTC)
- Read Packing for Mars by Mary Roach; she discusses this stuff in enjoyable detail. --jpgordon::==( o ) 04:56, 20 March 2011 (UTC)
- Death of Abigail Taylor tells me that no one should ever attempt sucking his or her butt. If the issue is that you just don`t want to go to bathroom, you might try catheter (not sure if it would work for moving bowels though) ~~Xil (talk) 10:48, 20 March 2011 (UTC)
- Read Packing for Mars by Mary Roach; she discusses this stuff in enjoyable detail. --jpgordon::==( o ) 04:56, 20 March 2011 (UTC)
- If you are concerned about the time and effort involved in voiding waste, those are both related to diet, notably dietary fiber intake. SemanticMantis (talk) 14:22, 20 March 2011 (UTC)
- I agree, if you have this problem, then its a sign that you should be eating more vegetables fruit and wholemeal grains. 92.15.21.23 (talk) 23:08, 20 March 2011 (UTC)
- I think they already exist, front side anyway. Fighter pilots like these http://www.bbc.co.uk/news/uk-12798613 have white tubes as part of their jumpsuit. On an eight-hour trip they are going to need one. Perhaps they are required to have an enema before leaving too. 92.28.241.202 (talk) 15:52, 20 March 2011 (UTC)
- But note that any vacuum used in such suits is low, only sufficient to remove the waste once voided, not to actually pull it out of the body. StuRat (talk) 19:23, 20 March 2011 (UTC)
- Likewise for the ones astronauts use. The vacuums in "space toilets" just replace gravity, they don't replace the body's own forces. --Tango (talk) 21:35, 20 March 2011 (UTC)
- But note that any vacuum used in such suits is low, only sufficient to remove the waste once voided, not to actually pull it out of the body. StuRat (talk) 19:23, 20 March 2011 (UTC)
How do Tomahawk missiles get to the target without getting shot down?
The Tomahawk cruse missile was used in several recent conflicts against countries with late Soviet air defense systems. They apparently reached their targets without interference, even before radar, antiaircraft defense, and fighter jets were incapacitated. The Tomahawk is a jet powered drone rather than a ballistic missile or rocket. The WW2 V1 flying bomb flew along at 400 mph, and WW propeller fighters could sometimes shoot them down, even with the primitive radar of the time. The Tomahawk only flies at 550 mph, comparable to a commercial airliner, and a fraction of the speed of even the old Mig and Mirage fighters operated by such countries as Iraq and Libya. Flying at low level to avoid radar was a common practice even in WW2, and did not really protect bombers from detection and damage. The ability to fly at 100 feet through canyons or whatever would not help while they are still out over the Mediterranean, where fighters might be deployed as a defense. Do second rate air defenses like Libya rely on ground based radar, and have nothing comparable to Awacs to "look down" and detect the Tomahawk in tome to fire a ground to air or air to air missile at one? Do the best Libyan fighter planes have "look down, shoot down" systems? Would a first rate world power be able to detect and shoot down Tomahawk quality missiles? This report from the Gulf War claims that only 60% of the Tomahawks actually hit their targets. Were some of the "misses" actually shootdowns? Edison (talk) 03:12, 20 March 2011 (UTC)
- They are sometimes shot down. This PBS page says that as many as 6 were shot down in the Gulf War (out of 297 fired). It also lists counts for many other reasons they didn't reach the target. The point of the Tomahawk is that it is cheap and dependable (and what they blow up costs a lot more than a few Tomahawk missiles). -- kainaw™ 04:10, 20 March 2011 (UTC)
- Cheap and dependable? The things cost $569,000 each in 1999 dollars,[1] which for a single-use weapon makes "cheap" a stretch. And according to the source cited by Edison, more than 40% of the time Tomahawks don't hit their intended target (often blowing up innocent civilians instead), which makes "dependable" a stretch. Red Act (talk) 09:39, 20 March 2011 (UTC)
- Cheap depends on context. If the alternative is even a 1% chance that your billion dollar bomber is shot down, then a cruise missile would look cheap. Dragons flight (talk) 11:12, 20 March 2011 (UTC)
- Is that really how much one of those missiles cost? I would have guessed a much higher price in the range of several million dollars. I think that's a relatively cheap price tag. Dauto (talk) 14:21, 20 March 2011 (UTC)
- I think you've identified some of the deficiencies in third rate militaries. Another big one is the lack of communication between systems. You need the radar systems (ground, sea, air, and satellite), to all be hooked to each other, so they can identify a "bogey", track it, and fire a missile at it when it comes into range. Even if you have all the components, if they aren't connected properly, it's just about useless. StuRat (talk) 08:37, 20 March 2011 (UTC)
- News media sometimes give the impression that when a destroyer or sub fires one of these things at a country, the target is doomed, but I still haven't seen arguments as to whether a country such as India, Pakistan, or the UK or US, for that matter could spot and intercept one or more fired, say from a submarine a hundred km offshore. If they are following a canyon or flying between hill, a few might be expected to hit those geographic features or even powerlines, and skimming treetops and wavetops was certainly a WW2 tactic. Radar at 30,000 feet looking down should spot it better than ground based radar, and jet fighters for the past several decades have flown much faster than these devices. If everything works right, the GPS should let the launching country put 1000 pounds of high explosive close enough to a target to blow it up, at about a million dollars per explosion, but I wonder if it has a positional uncertainty in tens or hundreds of meters, making it less effective against hardened targets than laser guided bombs, which (at least in selected footage from the attacks on Iraq) could be flown right in a window. They tend to use about 5 Tomahawks per target. Edison (talk) 20:13, 20 March 2011 (UTC)
- Then there's the additional problem that the Israelis had when using the US-built Patriot missile, during the Gulf War, to shoot down Iraqi SCUDs. The SCUDs were inaccurate, and carried minimal warheads, meaning they weren't likely to create much damage when they hit. Shooting them down meant that both the remnants of the SCUD and the Patriot would then fall, frequently in a populated region, causing as much damage as the intact SCUD would have. StuRat (talk) 20:50, 20 March 2011 (UTC)
- There is a significant difference in the consequences of shooting down a low flying cruise missile and that of shooting down a ballistic missile during its terminal phase. -- 119.31.121.89 (talk) 23:02, 20 March 2011 (UTC)
- Then there's the additional problem that the Israelis had when using the US-built Patriot missile, during the Gulf War, to shoot down Iraqi SCUDs. The SCUDs were inaccurate, and carried minimal warheads, meaning they weren't likely to create much damage when they hit. Shooting them down meant that both the remnants of the SCUD and the Patriot would then fall, frequently in a populated region, causing as much damage as the intact SCUD would have. StuRat (talk) 20:50, 20 March 2011 (UTC)
- A reasonable proportion of them are shot down, equally a proportion of them crash or miss. There are percentages out there for the various elements of that but you can track them down yourself. The real success figures are classified.
- The targeting process accounts for the likelihood of losing weapons and enough are launched to assure a sufficiently high number reach the target to deliver an effect.
- ALR (talk) 10:43, 21 March 2011 (UTC)
- Knowing where the enemy radar and missile sites are and their performance parameters allows a route to be planned that avoids as many of these defences as possible. Flying very low and using terrain masking also helps. A Tomahawk flying at or below 100 feet and 500+ mph will only be in the line of sight of someone on the ground for a matter of seconds - rendering manual weapons such as MANPADS or anti-aircraft guns fairly ineffective. Roger (talk) 14:42, 21 March 2011 (UTC)
- A country which expected an attack, like Libya, could be expected to deploy fighters at high altitude near the coast, or AWACS equivalent if they had such. Libya has Mig 21, Mig 23, and Mirage F1 fighters with service ceilings above 60,000 ft and speeds over Mach 2.1, compared to the Tomahawk's 550 mph (mach 0.7) speed. Did those or other Libyan aircraft have the ability to see and intercept Tomahawks better than the "man on the ground" defense discussed above? What defense would, say, India, Pakistan, the UK, the US, China, or Russia use against cruise missile attack, that was not available to Iraq? Would world powers rely on satellites to see and track cruise missiles? Edison (talk) 20:29, 22 March 2011 (UTC)
- See Look-down/shoot-down - it describes the ability some modern combat aircraft have to firstly detect a low flying target and distinguish it from "ground clutter" and secondly the ability to effectively engage such a target. Roger (talk) 20:51, 22 March 2011 (UTC)
Not a conspiracy theory question but a true scientific question
Was reading about the conspiracy theories floating around about the Earthquake and Tsunami in Japan. This is not a political or a conspiracy theory question, neither is it in any way intended to insult the suffering people now. I would like to know, is it possible( does technology exist) to artificially create earthquakes at an intended site and plan a tsunami? Whats the science behind this, how does this work?--Fragrantforever 05:13, 20 March 2011 (UTC) — Preceding unsigned comment added by Fragrantforever (talk • contribs)
- No, it is not possible for mankind to create earthquakes or tsunamis. The technology does not exist. The technology does exist to pinpoint the epicentre of any earthquake, and it is now known that earthquakes occur many kilometres below the Earth's surface. This is a depth at which mankind has never had any influence. Also, the energy involved in an earthquake is truly immense. It makes manmade sources of energy look miniscule.
- Psychology is the science of behavior. This science does exist. It is known that when people are deeply distressed they display a range of emotions (anger etc) not normally seen in people who are free from distress. Some of these emotions are demonstrably irrational, and can be of extreme intensity. One of the characteristics of anger is the ability to display antipathy towards another person, or other people. When people are angry they often display a readiness to accept suggestions and rumors about how another person has, or other people have, deliberately brought about the event that caused the deep distress in the first place. For example, during a war people have displayed a naive readiness to accept suggestions and rumors that the enemy is extremely bad and wants to cause extreme suffering and hardship. After the war, these suggestions and rumors have usually been found to have no foundation. Similarly, in the aftermath of an accident the victims often display a naive readiness to target a person or group of people, and to believe that the accident was either deliberate or solely due to the criminal negligence of this person or group of people.
- With this in mind, it is to be expected in the aftermath of the truly tragic earthquake, tsunami and nuclear radiation problems in Japan that conspiracy theories will quickly take root and circulate rapidly. Some of the victims of these tragedies will derive a little comfort from focussing on the idea that their tribulations were actually designed and caused by one or more very bad people. A conspiracy theory that the earthquake and tsunami were deliberately caused by human action is entirely consistent with some elements of our understanding of human psychology. Dolphin (t) 05:38, 20 March 2011 (UTC)
- It appears to be possible to induce very small earthquakes at a site by using injection wellbores to inject fluids. It can be a problem in oil and gas field development amongst other things. That's about it. Getting a fault to move by several metres over hundreds of kilometres of its length is a bit out of our league although I suppose it's theoretically possible in the same sense that dropping a copy of Yilmaz's Seismic Data Processing book out of a window in the middle of a city could, in prinicpal at least, make all of the buildings fall down if you were really very exceptionally unlucky... Sean.hoyland - talk 06:38, 20 March 2011 (UTC)
- An explosion can cause seismic wave and water waves, which probably is the reasoning behind conspiracy theories. Not sure, though, if explosion can mimic devastation of earthquake and tsunami ~~Xil (talk) 10:59, 20 March 2011 (UTC)
- The closest we can get to an artificial earthquake is to detonate a nuclear bomb underground, even this is of many orders of magnitude weaker than the earthquake that did happen in Japan. Besides, it's not something you can prepare and execute without drawing a lot of attention.
- Some kind of "Tesla-earthquake-machine" present in some cheap science fiction or video games is completely absurd. The Earth is not of uniform density to allow waves to resonate enough, and even if such thing would be possible, it's utter nonsense to be the cause of the current events: such a thing would need a lot of resources, a lot of scientists working on it, which needs a huge infrastructure, a lot of people who support this infrastructure, then the whole international scientific community, all current ad future university professors and students who would find out what caused it, and soon we get to a point where millions of people would need to be involved in such a conspiracy all over the world, from every country. For such a conspiracy to remain a secret is completely implausible, even if the technology required for it would be possible, which I highly doubt. The problem with most conspiracy theorists is, that if what they believe has a 0.001% chance of being true, they regard it as proof of it being true.
- Another "possibility" would be to deliberately not stop the reactor in time, but as in the above discussion, it would need millions upon millions of people from all over the world to be involved, so it's stupid to even consider it as a possibility.
- Conspiracies can and do happen in the world, but they are mostly in the range of "bribe a politician to buy a property cheaper", or "manipulate the media to get a slightly better image of your company or ideology", or "steal some money by misusing legislative loopholes". To invent some completely new technology, or manipulate the currently existing highest technology, and hope no one will find out, is complete nonsense. --87.169.11.121 (talk) 15:51, 20 March 2011 (UTC)
- A great deal of effort has been made to distinguish between earthquakes and underground explosions as part of monitoring the Test Ban Treaty using seismometers. Basically the computed focal mechanism shows whether the event involved movement on fault plane (producing the classic 'beachball plot') or was the result of an explosion (or in some cases an implosion such as in the collapse of old mine workings) where the plot is uniformly compressional (or tensional in the other case). Mikenorton (talk) 18:12, 20 March 2011 (UTC)
- One of the top results of a Google search claims that the nuclear accident was much bigger than we believe it to be, and happened before the earthquake, killing many thousands, and irradiating even more. The whole tsunami was than artificially created as a cover-up, just to wash away the bodies, and to add to the realism, some agents were later planted as "survivors" to be rescued. The proof: so few bodies have been found, because the water washed away most of them.
- The problem is, that there is no known technology to cause an earthquake this big, so the conspirators either managed to create, deploy and use it in a matter of hours, or they invested those horrible amounts of resources to build such an installation in the past, on the off chance that a nuclear meltdown might happen and than they could use that device to cover it up, while not using such groundbreaking new technology for anything else. --87.169.11.121 (talk) 18:54, 20 March 2011 (UTC)
- That is an amazingly silly conspiracy theory. --Mr.98 (talk) 22:05, 20 March 2011 (UTC)
- See: tautology. ;) --Tango (talk) 00:44, 21 March 2011 (UTC)
- That is an amazingly silly conspiracy theory. --Mr.98 (talk) 22:05, 20 March 2011 (UTC)
- The energy of the recent earthquake in Japan was about 3x1022 joules. The largest nuclear bomb (and nuclear bombs are the closest we've ever got to making our own earthquakes) ever tested had an energy of about 2x1017 joules. That's more than 10,000 times smaller. There is no way we could create our own earthquake on that scale. I guess it might be possible to trigger an earthquake that would have happened sooner or later anyway. There have been proposals to try and do that before too much energy builds up so we can trigger a small, harmless earthquake instead of the very large earthquake we would get instead. However, no-one has come close to inventing a way to actually do that. --Tango (talk) 21:51, 20 March 2011 (UTC)
Thanks for all the answers. The article I was reading mentioned something about HAARP Project in Alaska being behind the quake and tsunami. When I read the wikipedia page on HAARP i ended up more confused. As a secondary question to my initial question - AGREED ALL THIS IS BASELESS ASSUMPTION AND CONSPIRACY- where does HAARP fit into this? And let me remind everyone I dont beleive in these theories I was asking these questions for better understanding of the scientific issues behind this. Even when I posed my initial question, there was not an iota of doubt in me about all this being baseless theories but the idea of this reference desk is to spread the correct and valuable info and I decided to ask this so the informed would answer the less informed. thanks again. — Preceding unsigned comment added by Fragrantforever (talk • contribs) 06:30, 21 March 2011 (UTC)
- HAARP fits in because it's a common element of conspiracy theories. --Carnildo (talk) 01:46, 22 March 2011 (UTC)
global warming
one big argument for nuclear power is it is better than coal for greenhouse gasses that cause "global warming," but what about all the excess "heat" that nuclear power releases plus the warming of the cool liquid used to keep the core cool? Isn't that contributing to global warming by definition, or has that already been considered in the comparison?98.221.254.154 (talk) 05:27, 20 March 2011 (UTC)
- Nuclear fission does produce heat, just as coal does, but the concern about global warming comes from the carbon dioxide produced, not the initial heat produced. Carbon dioxide keeps sunlight from escaping Earth's atmosphere, reflecting it back toward the Earth's surface. So when you release CO2 into the air, it contributes to global warming via sunlight for as long as it is there. Nuclear fission does not produce CO2, so it doesn't really contribute to global warming.Aaron (talk) 05:51, 20 March 2011 (UTC)
- Aaron's last sentence makes more sense as Nuclear fission does not produce CO2, so it doesn't really contribute to the Greenhouse effect. Greenhouse effect is retardation of the escape of heat from the Earth. Nuclear fission produces heat so it contributes to warming, but it doesn't produce CO2 so it doesn't contribute to the greenhouse effect. Dolphin (t) 07:03, 20 March 2011 (UTC)
- Is there some way to relate the global warming effects of greenhouse gas emission to that of heat production? That is, how many joules of heat would I have to add to the atmosphere to bring about an equivalent warming to that caused by the release of one ton of CO2? -- 119.31.126.66 (talk) 08:19, 20 March 2011 (UTC)
- Total global energy consumption is about 15 terawatts. The man-made effect of accumulated greenhouse gases is about 820 terawatts. So the man-made greenhouse effect is about 50 times the direct heating effect. Also, because greenhouse gases accumulate and have a long residence time in the atmosphere, that ratio is likely to increase over time. Dragons flight (talk) 08:42, 20 March 2011 (UTC)
- Also any direct heating increases the amount of infrared radiation emitted by the earth's surface which has a cooling effect which substantially cancels the direct heating. That's why any direct heating is essentially negligible. Dauto (talk) 14:07, 20 March 2011 (UTC)
- Total global energy consumption is about 15 terawatts. The man-made effect of accumulated greenhouse gases is about 820 terawatts. So the man-made greenhouse effect is about 50 times the direct heating effect. Also, because greenhouse gases accumulate and have a long residence time in the atmosphere, that ratio is likely to increase over time. Dragons flight (talk) 08:42, 20 March 2011 (UTC)
- (It should be noted, of course, that while the act of fission releases no greenhouse gases, the full fuel cycle is not carbon neutral. It's just tremendously better, per megawatt of energy produced, than fossil fuels. It produces about .5-4% the CO2 emissions as coal.[2]) --Mr.98 (talk) 15:34, 20 March 2011 (UTC)
- May I suggest that the IAEA is not a particularly non-partisan source, and that any paper that starts with "the Uranium Institute (UI) decided to examine these claims and to attempt to refute them in more detail" is dubious as a scientific source. --Stephan Schulz (talk) 15:52, 20 March 2011 (UTC)
- IAEA is a global independent organisation that reports to the UN. It's as unbiased as it gets. --85.77.43.229 (talk) 16:20, 20 March 2011 (UTC)
- May I suggest that the IAEA is not a particularly non-partisan source, and that any paper that starts with "the Uranium Institute (UI) decided to examine these claims and to attempt to refute them in more detail" is dubious as a scientific source. --Stephan Schulz (talk) 15:52, 20 March 2011 (UTC)
- The numbers they cite look fairly legit to me. If you have better numbers, have at it. The real bait and switch here is obviously comparing it to coal and coal only — it would be more useful to compare it to things other than the dirtiest form of energy production we have. However I find it completely plausible that nuclear does pretty good when stacked up against coal when measured in terms of CO2 emissions — or practically anything else. Coal is bad news. --Mr.98 (talk) 17:25, 20 March 2011 (UTC)
- I don't think anybody needs to actually read that paper to realize that nuclear power produces much less Co2 than coal. Dauto (talk) 18:03, 20 March 2011 (UTC)
But why is the average temperature of the atmosphere the gauge for this phenomenon, when you say it is about the CO2 level? why wouldn't a gauge be CO2 PPM, and call it global smogging? —Preceding unsigned comment added by 98.221.254.154 (talk) 03:24, 22 March 2011 (UTC)
Expression for Thrust and Power coefficients
Hey, can anyone tell me the expression for Thrust Coefficient and Power Coefficient for a propeller in terms of Re, Mach Number and J ? Yes Michael? •Talk 10:45, 20 March 2011 (UTC)
The relationship between these two coefficients and advance ratio J is shown graphically. I am looking at Chapter XI of Theory of Flight by Richard von Mises (1959), Dover Publications. This is now a very old book and I'm sure this information is available in all modern books on practical aerodynamics. Dolphin (t) 11:03, 20 March 2011 (UTC)
In Aerodynamics by L.J. Clancy (1975), Pitman Publishing Ltd, Section 17.3, there is also a definition of the Torque Coefficient, CQ:
Dolphin (t) 11:14, 20 March 2011 (UTC)
- Well, I was looking for an expression for itself. Also, if there is an expression for Thrust by Torque, can you let me know? Yes Michael? •Talk 11:32, 20 March 2011 (UTC)
- These three coefficients vary with advance ratio in a way that is unique for any given design of propeller. There is not a mathematical relationship between coefficient and advance ratio, and the relationships must be determined empirically (ie by experiment) in the same way that the lift coefficient of a particular airfoil section varies with angle of attack and must be determined empirically. Firstly, determine exactly which propeller you want to consider, then go looking for three diagrams which show the relationship between advance ratio and each of the three coefficients for this propeller. Such diagrams will be available for a range of advance ratios from zero up to some maximum value, just as the lift coefficient of an airfoil can be shown on a diagram for a range of angles of attack from zero (or even negative) up to the stalling angle and a bit beyond.
- Propeller manufacturers are likely to be reluctant to supply this information about their products, but all advanced text books about propellers should contain this information for at least one design of propeller. Dolphin (t) 21:47, 20 March 2011 (UTC)
- Have a look at Figure 2 in THIS web article. Dolphin (t) 03:43, 21 March 2011 (UTC)
Flat roof vs. sloped roof
Where is each of the options necessary? Can you have a flat roof in places where it snows?
- Snow ifself is not an absolute showstopper. If only the snow melts in the summer, all you need to do is make the roof construction strong enough to carry the weight of one winter's worth of snowfall.
- Liquid water is much more of a problem. Even slight deviations from perfect flatness will make rainwater (or meltwater) stand in shallow pools on the roof instead of running off, and it's hard to construct a roof surface that is watertight enough not to be damaged by this in the long run -- especially if temperatures reach freezing in the winter.
- Anecdotally, flat roofs were popular in Denmark abound 1970, but most of them have since been overbuilt with peaked roofs due to recurring water damage. –Henning Makholm (talk) 15:06, 20 March 2011 (UTC)
- OR: We have a flat roof in southern Ontario (Canada) where we get a lot of winter snow and a lot of days below freezing. Parts of the tar-and-gravel roof are 30 years old and parts only about 5 years old. We had one problem with a leak along one seam when storms came driving out of the east. It was repaired with an overlay of tar. Aside from that, we are warm and dry. The norm, however, is a pitched roof in such climates. Bielle (talk) 15:16, 20 March 2011 (UTC) P.S. Almost all commercial buildings of whatever floor area or height have flat roofs, and it is a rare one (though it does happen) that collapses under a snow load or leaks. Bielle (talk) 15:24, 20 March 2011 (UTC)
- One factor seems to be the width of the building (by width I mean the direction in which the roof would have an elevation difference, if sloped, which is usually the narrowest dimesnion). The wider the roof, the higher it has to be, if sloped, so snow will tumble off. This means the material required varies roughly with the square (width×height) of the width. (It just varies linearly with the length, as expected.) So, if a building is 10x as wide, a sloped roof would take 100x as much material, cost 100x as much, etc. This quickly makes sloped roofs impractical for large buildings (an exception being perhaps the pyramids, where the roof and the building are one in the same ?). StuRat (talk) 19:16, 20 March 2011 (UTC)
- As StuRat says, for a building of significant width, say more than 80 feet (24 m), one finds that the volume of structure for an appreciable slope becomes expensive. Multiple adjoining sloped roofs have issues with snow and water retention in the valleys that tend to discourage the use of that configuration. Simple sloped roofs are in general less vulnerable to leakage, since water doesn't linger. However, nobody nowadays designs a "flat" roof - there's always a modest slope to encourage drainage, although it may not be obvious on casual examination. Acroterion (talk) 22:09, 20 March 2011 (UTC)
- In addition to the roof installation being more expensive, having a sloped roof on a large building would cost more to heat/insulate/etc. If you have a sloped roof, the heat is going to want to accumulate in the peak of the roof. That's not where the people are in a large building. And if you have a ceiling with attic, then you have to insulate the floor of the attic as well. Dismas|(talk) 07:15, 21 March 2011 (UTC)
- Flat roofs are not actually flat normally. It may only be a 1 in 200 slope or even less for a hard concrete roof where it isn't going to sag and form ponds but a slope is put in so any water runs off. Dmcq (talk) 16:24, 21 March 2011 (UTC)
- One reason for at least a minimal slope is to avoid cumulative deflection under ponding, where water accumulates in an uneven section, the roof sags, more weight, more sagging, more water ... problem. Acroterion (talk) 21:03, 22 March 2011 (UTC)
Birdsong, UK
Yesterday in the suburbs and the countryside of south-eastern England I heard a lot of bird calls similar to this: Low-High-Low-High-Low-High-Low-High. Different birds sang between four and nine notes, all done quickly and without any pause in between the notes. The notes sounded more like something being plucked or twanged rather than whistled.
Is this sufficient to identify a particular species, or are there several species that sound similar? Is there anything like a Flora for birdsong? Thanks 92.28.241.202 (talk) 16:08, 20 March 2011 (UTC)
- Basically this is the call of the Tit species. Great Tits sound like "teacher, teacher". The smaller tits call higher and quicker. --TammyMoet (talk) 16:57, 20 March 2011 (UTC)
Thanks, the song description matched. I did not realise there were so many of them. Perhaps they have been eating the bees. Does anyone know which are the commonest tit species in SE England? 92.28.241.202 (talk) 17:05, 20 March 2011 (UTC)
- I suspect the blue tit is the commonest in SE England, but populations can fluctuate wildly from year to year. By the way, there are a number of websites where you can check out bird songs. This is one.--Shantavira|feed me 18:01, 20 March 2011 (UTC)
From that wonderful link of Shantavira's, it must have been a great tit. 92.28.241.202 (talk) 19:35, 20 March 2011 (UTC)
Why do old AA batteries appear to sweat?
I've often found that old batteries in transistor radios etc are often covered in tiny drops of clear fluid, like sweat. The batteries that I've just looked at are metal-covered alkali batteries, so the "sweat" may be simply condensation. But very old zinc-carbon batteries often appear to have moisture underneath their plastic sleeve.
Why do batteries appear to sweat? Thanks 92.28.241.202 (talk) 16:57, 20 March 2011 (UTC)
- Probably because they build up deposits of some sort of salt, which draws moisture out of the air, especially if you live in a very humid place such as Great Britain. Looie496 (talk) 17:42, 20 March 2011 (UTC)
- Thanks, but GB is not a "very humid place" as our American chums seem to believe. Fogs are infrequent or rare. 92.28.241.202 (talk) 18:23, 20 March 2011 (UTC)
- Oh please. I live in Britain, and it is indeed a damp, humid place most of the time. It has lower precipitation rates than many places in the USA, but it spreads them out over many days so we get days of mist, drizzle and, yes, fog. Fogs are not infrequent, especially in the cooler part of the year in the early morning and evening. We get river-mist here most mornings. How are our houses traditionally built? With sloping roofs that protrude past the walls, and with gutters when people can afford them. Because of all the rain. Recent improvements? Cavity walls anywhere even slightly exposed, because of all the rain and drizzle that gets driven against the walls by the wind. We have damp coursing as standard, and basements are rare. Mould and damp are common in certain parts of houses, because we live in a damp country. It is humid here most of the time: it is considered noteworthy when it is warm and dry, and people get over-excited.
- This is why we were good at growing corn for the Romans. This is why we did so well at wool manufacture. This is probably why your batteries behave this way. Unless you live somewhere with a specially dry microclimate? 86.164.66.59 (talk) 19:42, 20 March 2011 (UTC)
- Your experience is very different from mine - where are you? What you describe sounds like an extreme exaggeration. (I detect the Northern/Midlands mantra of "We're miserable, and it's all your (comfy southerners) fault!") You must be living in one the wettest parts of the country, somewhere like Manchester or the Lake District, or Scotland. In London its about 20 inches of precipitation a year. Its hardly a rain forest or the kind of place where they have monsoons - they are "very humid places", and has less rain that most parts of europe or the western side of the US. Corn needs a dry climate to ripen by the way - as far as I understand it will not grow in Scotland, hence the oats. Wool thread manufacture was purposedly done in a damp rainy part of the country. You forgot to mention the mushrooms growing out of the carpet, lol. 92.28.241.202 (talk) 20:05, 20 March 2011 (UTC)
- This image of unclear provenance seems to support the claim that London is a humid place. It's true that London is not very foggy. According to Wikipedia, London fog was pea soup fog, which is actually smog, and disappeared with the end of the coal-burning era. -- BenRG (talk) 20:44, 20 March 2011 (UTC)
- I agree that in mid-winter it may be more humid than it is in most parts of North America, the reason being because in England its above freezing most of the time, and so the water vapour in the air does not freeze into snow etc. 92.15.21.23 (talk) 22:20, 20 March 2011 (UTC)
- That humidity scale is grossly exaggerated. Where I am now, the humidity is only 42%, which is fairly typical. Its 42% indoors: outdoors it would be less. "Mould and damp are common in certain parts of houses" says our friend above - rubbish! Only if you are living in a cave or a slum. According to that image, a "wet day" is a day with more than 0.1mm of precipitation - you would have great difficulty measuring a tenth of a millimetre. I think that image is a fraud, as it also says that the hottest temperature is only about 60 degrees farehnheit in the summer ...... hey, is this London, Canada? Very funny. 92.15.21.23 (talk) 21:49, 20 March 2011 (UTC)
- This image of unclear provenance seems to support the claim that London is a humid place. It's true that London is not very foggy. According to Wikipedia, London fog was pea soup fog, which is actually smog, and disappeared with the end of the coal-burning era. -- BenRG (talk) 20:44, 20 March 2011 (UTC)
- Who in Britian can't afford gutters? They are just a few bits of plastic... --Tango (talk) 22:03, 20 March 2011 (UTC)
- Britons are not pieces of plastic. Their Rain gutters are constructed from materials such as cast iron, lead, zinc, galvanised steel, painted steel, copper, painted aluminium, require an outflow channel leading away from the building at ground level, need leaves to be cleared in case of blockage, and occasionally need repair e.g. after loading by snow or leaves. None of this comes free. Cuddlyable3 (talk) 09:44, 21 March 2011 (UTC)
- If we didnt have gutters we'd be living in a desert. And even primitive houses in deserts have rudimentary gutters. The picture linked to above was taken in Australia. 92.15.25.108 (talk) 11:27, 21 March 2011 (UTC)
- The UK has a wide range of annual rainfall (from about 15 inches to more than 200 inches). In an area such as the one where I live, with up to 100 inches a year, it does tend to feel damp (with high humidity) for most of the year, and it is very difficult to keep damp out of houses, though mould growth tends to be quickly dealt with to avoid slum conditions. Yesterday was 100% humidity all day in the low cloud. Dbfirs 14:36, 21 March 2011 (UTC)
- 100 inches a year is very rare and is almost the worst rainfall you can find in Britain, and is nearly five times worse than what you get in London. I think there is somewhere on top of a hill in the Lake District that gets 150 or more inches a year, but apart from a farmhouse or two nobody lives there. 92.15.25.108 (talk) 16:56, 21 March 2011 (UTC)
- Yes, it's not quite as wet where I live as it is in Seathwaite(Seathwaite, Allerdale), but 100 inches is not particularly rare in the valleys between the "fells" - and people do live there! I agree that 100 inches a year would be rare for densely populated areas in the UK. Dbfirs 08:05, 22 March 2011 (UTC)
- As you know this is due to the prevailing south west wind in Britain sweeping in rain clouds from the Atlantic. They dump their rain over the high elevations mainly to the west, such as the Lake District and Wales, and the east is consequently comparatively dry and sunny. You are unlucky/lucky to live close to the Lake District. 92.15.6.157 (talk) 10:42, 22 March 2011 (UTC)
- Yes, it's not quite as wet where I live as it is in Seathwaite(Seathwaite, Allerdale), but 100 inches is not particularly rare in the valleys between the "fells" - and people do live there! I agree that 100 inches a year would be rare for densely populated areas in the UK. Dbfirs 08:05, 22 March 2011 (UTC)
- 100 inches a year is very rare and is almost the worst rainfall you can find in Britain, and is nearly five times worse than what you get in London. I think there is somewhere on top of a hill in the Lake District that gets 150 or more inches a year, but apart from a farmhouse or two nobody lives there. 92.15.25.108 (talk) 16:56, 21 March 2011 (UTC)
- The UK has a wide range of annual rainfall (from about 15 inches to more than 200 inches). In an area such as the one where I live, with up to 100 inches a year, it does tend to feel damp (with high humidity) for most of the year, and it is very difficult to keep damp out of houses, though mould growth tends to be quickly dealt with to avoid slum conditions. Yesterday was 100% humidity all day in the low cloud. Dbfirs 14:36, 21 March 2011 (UTC)
- Most modern gutters in Britain are plastic. They aren't free, sure, but they aren't something only rich people have by any stretch of the imagination. Any modern house will be built with gutters. Almost all old houses have gutters too. If you don't have any gutters, rain just falls straight off the roof onto the ground, which isn't a good idea. The ground around your house would get very wet and so would you when you walked past. --Tango (talk) 19:51, 21 March 2011 (UTC)
- If we didnt have gutters we'd be living in a desert. And even primitive houses in deserts have rudimentary gutters. The picture linked to above was taken in Australia. 92.15.25.108 (talk) 11:27, 21 March 2011 (UTC)
- Britons are not pieces of plastic. Their Rain gutters are constructed from materials such as cast iron, lead, zinc, galvanised steel, painted steel, copper, painted aluminium, require an outflow channel leading away from the building at ground level, need leaves to be cleared in case of blockage, and occasionally need repair e.g. after loading by snow or leaves. None of this comes free. Cuddlyable3 (talk) 09:44, 21 March 2011 (UTC)
- Your experience is very different from mine - where are you? What you describe sounds like an extreme exaggeration. (I detect the Northern/Midlands mantra of "We're miserable, and it's all your (comfy southerners) fault!") You must be living in one the wettest parts of the country, somewhere like Manchester or the Lake District, or Scotland. In London its about 20 inches of precipitation a year. Its hardly a rain forest or the kind of place where they have monsoons - they are "very humid places", and has less rain that most parts of europe or the western side of the US. Corn needs a dry climate to ripen by the way - as far as I understand it will not grow in Scotland, hence the oats. Wool thread manufacture was purposedly done in a damp rainy part of the country. You forgot to mention the mushrooms growing out of the carpet, lol. 92.28.241.202 (talk) 20:05, 20 March 2011 (UTC)
- Thanks, but GB is not a "very humid place" as our American chums seem to believe. Fogs are infrequent or rare. 92.28.241.202 (talk) 18:23, 20 March 2011 (UTC)
- See Alkaline battery#Leaks Potassium hydroxide electrolyte can leak out of old alkaline batteries. When it dries it can leave a white residue I would expect electrolyte leakage is the source of moisture on an old failed alkaline battery, rathre than condensation of atmospheric moisture, unless the battery was brought into a moist place from a cold place. Carbon zinc batteries were worse in this respect in terms of destroying an device when the batteries were left in it too long. Edison (talk) 20:00, 20 March 2011 (UTC)
"This is why we were good at growing corn for the Romans.": your assertion is ridiculous. The Roman didn't know corn until the XVI century, when there were not Romans anymore... 212.169.178.75 (talk) 22:55, 20 March 2011 (UTC)
- "Corn" was (and still is) the generic term used in the Old World to cover all cereal crops, including wheat, barley, rye and others. When John Constable painted "The Cornfield" he wasn't looking at maize. (The term could also refer to non-food granular particles - "corned beef" is so called because it is preserved using salt in the form of coarse grains, or corns). As applied to New World maize, "corn" is a contraction of the original "Indian corn", i.e. a particular type of cereal. {The poster formerly known as 87.81.230.195} 90.201.110.155 (talk) 00:37, 21 March 2011 (UTC)
- Please make at least a small attempt to stay on topic. "Corn" has nothing to do with alkaline batteries. Edison (talk) 02:04, 21 March 2011 (UTC)
- However they were responding to an incorrect or confused assertion (which IMO shouldn't have gone unchallenged) by 212 (who were responding to a point by 86). Edit: Forgot to mention this but the big long discussion up there which has gotten longer since I first posted about whether or not the UK can be considered a 'wet' country (which considering 'wet' is subjective seems a bit pointless) is IMHO a bigger issue then the clarification that the Romans did grow corn. Nil Einne (talk) 08:53, 21 March 2011 (UTC)
- Please make at least a small attempt to stay on topic. "Corn" has nothing to do with alkaline batteries. Edison (talk) 02:04, 21 March 2011 (UTC)
About duck being a red meat...
With all the current hoopla about the risks of red meat, I'm trying to determine if duck is counted as one for the purposes of said elevated health risks. The article about red meat is unclear here... Egg Centric 18:52, 20 March 2011 (UTC)
- That's a good question, and I agree that the article may be contradictory. It says that red meat includes 'duck' but then goes on to talk about a bunch of health risks associated with 'red meat' when in fact the studies may or may not have included duck. What you'd have to do is go to the studies themselves. 220.244.35.181 (talk) 19:16, 20 March 2011 (UTC)
- Red meat is a phrase that was invented and pushed by the beef industry to refer to "beef" whenever health risks of eating beef are discussed. Thus, when beef is bad for you, it is called "red meat", but when beef is good for you, it is called "beef". Sort of a form of reverse marketing, so in your mind, you don't associate beef with unhealthy qualities. Duck does not fit into the "Standard" American triumverate of meat protein (Beef, Pork, and Chicken), so I am not sure that most people would think of duck as being substantially different from Chicken, excepting that ALL duck is, culinarily and probably nutritionally, closer to "dark meat chicken" (i.e. lower quarters, thigh and leg), even duck breast is more like chicken legs than anything. Whiter meats (including chicken breast meat, turkey breast meat, and some parts of the pork, like the loin and the tenderloin) are lower in fat, so for people who care about fat intake, they advise people to stick to "whiter" meats. Also, with regard to duck being "red meat", it can be culinarily treated more like "beef" than "chicken", so for example, duck is still tasty when cooked to "medium rare", like beef is, but unlike chicken where "medium rare" chicken is disgusting. Nutritionally, however, I don't know that duck is distinctly more like beef or chicken. --Jayron32 22:35, 20 March 2011 (UTC)
- I disagree with your contention about the origin of the term "red meat", Jayron, though I agree some anti-meat nutritionalists may use it in that way now. I can recall many references to "good red meat" or just "red meat" in an approving tone from writings going back many decades: the term simply distinguished redder mammalian meats from the whiter meat typically found in domesticated birds. Wild birds' meat tends to be darker than that of domesticated fowl, though not "red", because the wild birds exercise it more. Although some domesticated ducks are bred for meat, they are less distant from their wild forebears than domestic chickens, and of course wild ducks are also often killed for the table. {The poster formerly known as 87.81.230.195} 90.201.110.155 (talk) 00:49, 21 March 2011 (UTC)
- Origins aside, many kiwis are probably familiar with the promotion of red meat (sometimes under that name) by Beef & Lamb NZ [3] some of which are available here [4] Nil Einne (talk) 08:30, 21 March 2011 (UTC)
- @90.201/Jayron - I was under the same impression as Jayron regarding the origin of the term, but it occurs to me know that I have absolutely no reference to back that up. Do either of you have anything to offer in terms of support? I did some Googling, but didn't get anything much at all and our article doesn't really cover it. Matt Deres (talk) 01:40, 22 March 2011 (UTC)
- The (1933) OED has two citations: the first, purely descriptive one is from M Donovan's Domestic Economy Vol II of 1837; the second is from P Manson's Tropical Diseases of 1898 and advises avoiding it (though presumably in a particular context). Beyond that I can only say that I (being in my 50s) have always been familiar with the term , and have only encountered suggestions that red meat might be unhealthy within, say, the last 15. Personally I take such claims with a large pinch of salt. (Only a metaphorical one, before we start down that road as well!) {The poster formerly known as 87.81.230.195}90.201.110.155 (talk) 18:32, 24 March 2011 (UTC)
- I disagree with your contention about the origin of the term "red meat", Jayron, though I agree some anti-meat nutritionalists may use it in that way now. I can recall many references to "good red meat" or just "red meat" in an approving tone from writings going back many decades: the term simply distinguished redder mammalian meats from the whiter meat typically found in domesticated birds. Wild birds' meat tends to be darker than that of domesticated fowl, though not "red", because the wild birds exercise it more. Although some domesticated ducks are bred for meat, they are less distant from their wild forebears than domestic chickens, and of course wild ducks are also often killed for the table. {The poster formerly known as 87.81.230.195} 90.201.110.155 (talk) 00:49, 21 March 2011 (UTC)
- Nutritionally, duck is definite more chicken than beef. The biggest problem with red meat is the mammalian hemoglobins--not the fats. Imagine Reason (talk) 11:21, 22 March 2011 (UTC)
- What, exactly, is wrong about those mammalian hemoglobins? 93.132.164.231 (talk) 21:38, 22 March 2011 (UTC)
- Red meat is a phrase that was invented and pushed by the beef industry to refer to "beef" whenever health risks of eating beef are discussed. Thus, when beef is bad for you, it is called "red meat", but when beef is good for you, it is called "beef". Sort of a form of reverse marketing, so in your mind, you don't associate beef with unhealthy qualities. Duck does not fit into the "Standard" American triumverate of meat protein (Beef, Pork, and Chicken), so I am not sure that most people would think of duck as being substantially different from Chicken, excepting that ALL duck is, culinarily and probably nutritionally, closer to "dark meat chicken" (i.e. lower quarters, thigh and leg), even duck breast is more like chicken legs than anything. Whiter meats (including chicken breast meat, turkey breast meat, and some parts of the pork, like the loin and the tenderloin) are lower in fat, so for people who care about fat intake, they advise people to stick to "whiter" meats. Also, with regard to duck being "red meat", it can be culinarily treated more like "beef" than "chicken", so for example, duck is still tasty when cooked to "medium rare", like beef is, but unlike chicken where "medium rare" chicken is disgusting. Nutritionally, however, I don't know that duck is distinctly more like beef or chicken. --Jayron32 22:35, 20 March 2011 (UTC)
Potassium Iodide
Would it be bad to store potassium iodide in water? I diluted potassium iodide (SSKI) in water, would it make the shelf like any less or would it make it less effective if it was stores like this overtime? —Preceding unsigned comment added by 76.169.33.234 (talk) 20:54, 20 March 2011 (UTC)
- Potassium iodide is fully soluble, highly stable, and not likely to be a food source for any microbes. In other words, I can't see anything happening to it whether it is in solution or solid form. In either solution or solid form, it should outlive all of us. --Jayron32 22:26, 20 March 2011 (UTC)
Sea kelp and iodine
If I have sea kelp that says it has 0.06% iodine, how much would I have to take for it to be equivalent to 100mg of iodine which is what I read is equivalent to the amount of iodine in a 130mg tablet of potassium iodine pill? Thanks —Preceding unsigned comment added by 76.169.33.234 (talk) 21:01, 20 March 2011 (UTC)
- 0.06% of what? Is it 0.06% of the total mass of the seakelp or 0.06% of the Recommended Daily Allowance of iodine for an adult human? If it is the former, you would need to eat 100mg/.0006 = 16,667 mg or 16.667 grams. If it is the latter, you would first need to know what the RDA for iodine was... --Jayron32 22:24, 20 March 2011 (UTC)
- I think you slipped a decimal place somewhere, Jayron: I make it 166.67g both on my calculation and on your figures. Happy munching, OP! Incidently, this all assumes that the iodine in the kelp is as assimilable as that in the potassuim iodide in the tablet, which is unlikely. {The poster formerly known as 87.81.230.195} 90.201.110.155 (talk) 00:23, 21 March 2011 (UTC)
- You shouldnt take any iodine, unless you are in Japan close to the reactors. See http://www.bbc.co.uk/news/health-12784774 92.15.21.23 (talk) 22:33, 20 March 2011 (UTC)
- Or you have some medical condition for which your doctor has prescribed iodine supplements. (And, by the way, when we say "close to the reactors" we mean actually being one of the people working on fixing them. Even if you are just a few hundred metres away, you shouldn't need iodine supplements.) --Tango (talk) 00:40, 21 March 2011 (UTC)
Not to be pendandic, but this conversation should be about iodide, not iodine. If you are considering consuming them, mixing up the two could be dangerous. 71.185.49.174 (talk) 22:40, 20 March 2011 (UTC)
- No, it couldn't. Iodide is just iodine with an extra electron. The best way to get extra iodine into your body is taking ionic compounds of iodine and something else, usually potassium, so it that context we say "iodide", but it's the same thing. --Tango (talk) 00:40, 21 March 2011 (UTC)
- Um, excuse me, but chloride is just chlorine with an extra electron, and its effects on the body are quite different. That extra electron makes a big difference. Looie496 (talk) 01:14, 21 March 2011 (UTC)
- I just went into this above, but since this is a more appropriate title I'll paste it here for the archive: "for edible seaweeds e.g. kelp: "12 different species of seaweeds were analyzed for iodine content, and found to range from 16 microg/g (+/-2) in nori (Porphyra tenera) to over 8165 +/- 373 microg/g in one sample of processed kelp granules (a salt substitute) made from Laminaria digitata.";[5] "Edible seaweed contained I levels of between 4300 and 2,660,000 micrograms/kg";[6] (summarizing these two) "the average iodine content of kelp of 1,500 to 2,500 μg/g".[7] So we're looking at roughly 2 mg of iodine per gram of kelp (I assume these are all dry weight), if you happen to get an average sample, with a just ridiculous amount of variation. So eating 65 grams, a plausible dose, would be equivalent to the 130 mg tablet - though you might end up getting four times as much if you are unlucky. Or you might get less than a mg. Wnt (talk) 02:38, 18 March 2011 (UTC)"
- In some sources I read while preparing that last, iodine and iodide were used almost interchangeably, in the sense that the weight of iodide is the same as the weight of iodine. (neglecting the minisule electron mass) Actually eating iodine in its elemental form (or as tincture of iodine) is inadvisable for a variety of reasons, the least of which being that whatever physically reacts with and stains your sorry gullet is not going to your thyroid. Wnt (talk) 02:21, 21 March 2011 (UTC)
- A quick raid on NCBI suggests that kelp stores iodide as just plain iodide, noncovalently associated with other molecules.[8] So its iodide should be interchangeable with that from KI, at least in theory. Wnt (talk) 02:34, 21 March 2011 (UTC)
- Um, excuse me, but chloride is just chlorine with an extra electron, and its effects on the body are quite different. That extra electron makes a big difference. Looie496 (talk) 01:14, 21 March 2011 (UTC)
- I was asking about this product http://dealnay.com/1011927/natures-way-kelp-100-capsules.html I heard you can take it in the place of potassium iodide, I guess you can't... Thanks —Preceding unsigned comment added by 76.169.33.234 (talk) 02:59, 23 March 2011 (UTC)
Tidal energy from the Wash and the Severn
How many typical nuclear power stations would harnessing the tides of the Wash and Severn be equivalent to? 92.15.21.23 (talk) 22:01, 20 March 2011 (UTC)
- It would depend on the placement of the barrages and also which types of nuclear power stations you wish to compare them to. For instance, the proposed Severn Barrage may generate from 0.75-15GW depending on which plan you read. The proposed Hinkley Point C nuclear power station could produce 1.6GW. Nanonic (talk) 22:21, 20 March 2011 (UTC)
- The 15GW figure is peak power, which isn't terribly informative when you're costing it, compared with a source with a fairly steady rate. Unfortunately the article isn't very good at giving idea (beyond the rough "average" numbers below) as to how long a given barrier would spend delivering power at that level, at the average level, and at lower levels. -- Finlay McWalter ☻ Talk 22:31, 20 March 2011 (UTC)
- There are many different proposals for designs for a Severn Barrage, with quite a range of costs, power levels, and impacts. Looking at that article, the 1987 proposal would generate 313 MW on average, the 1989 design 2,000 MW on average. If you compare that to Torness Nuclear Power Station, the most productive of the UK's Advanced gas-cooled reactors, which produces at 1250 MW over two reactors. the Severn Barrage article, using those 1989 figures, puts the yield at 3 reactors worth, and observes that the estimated cost is "about the same as six nuclear reactors, but different lifespan". If Torness serves its planned 35 years of service, you'd expect a Barrage of the 1989 design to pass nuclear at some age shy of 70 years. But that's a hopelessly simplistic calculation: on the nuclear side it doesn't count the comparative cost of operating and maintaining both plants, and the cost of the fuel cycle; on the tidal side it doesn't count the (presumably fairly low) running and maintenance cost, or the (difficult to put into numbers, but not trivial) cost of the environmental impact the barrier would bring. So, handwaving a bit, power yield of 1 1/2 nuclear stations, more expensive in the short term but cheaper in the long term. -- Finlay McWalter ☻ Talk 22:24, 20 March 2011 (UTC)
I hate this "environmental impact" twaddle - who cares about a few ducks. 92.15.21.23 (talk) 22:30, 20 March 2011 (UTC)
- Nobody cares that you don't care about a few ducks. This is a reference desk. Personal opinions are off-topic. --Tango (talk) 23:09, 20 March 2011 (UTC)
- The ducks probably care. Sean.hoyland - talk 04:00, 21 March 2011 (UTC)
- Personal opinions from the OP about what the OP is or isn't interested in are perfectly on topic, and in fact define the topic. Turns out the scope of the question does not include impact on ducks. Now we know. 81.131.35.68 (talk) 06:08, 21 March 2011 (UTC)
Ducks and the pro-duck lobby are relevant because they can scupper plans to use tidal energy instead of building more nuclear reactors. However the plans to end repair of coastal defenses along the east coast may introduce more habitat for them, although the crowd-pleasing current government seems to be appearing to reverse that policy. If you've ever been to Hunstanton you can see how ugly the mud beaches are (Old Hunstanton on the corner of the coast is much nicer) so damming the Wash will be a big improvement for recreation. 92.15.25.108 (talk) 12:08, 21 March 2011 (UTC)
- By "the pro-duck lobby" you may mean the Ramsar Convention, which is an international treaty designed to protect the fundamental ecological functions of wetlands. Both the Severn Estuary and the Wash are listed here as being of international environmental importance. Perceived "ugliness" has nothing to do with it. Ghmyrtle (talk) 12:21, 21 March 2011 (UTC)
See what I mean? 92.15.25.108 (talk) 13:47, 21 March 2011 (UTC)
- Not really. Many people including some locals consider the protection of wetlands in Malaysia and Indonesia important. I don't believe ducks are even commonly present in these Nil Einne (talk) 16:06, 21 March 2011 (UTC)
Chernobyl vs Deepwater Horizon
In terms of environmental damage (both present and predicted by environmentalists), how does the Deepwater Horizon incident compare to Chernobyl? Thanks. 72.128.95.0 (talk) 23:06, 20 March 2011 (UTC)
- They're not really comparable. --Tango (talk) 23:11, 20 March 2011 (UTC)
- Deepwater did almost nothing - it requires intense study to find any negative effects at all. Chernobyl caused a 30km area to be uninhabitable for centuries. I should point out that the environmental damage from hydrocarbons comes in the burning, not the extraction, so comparing accidents is not very meaningful. Ariel. (talk) 00:01, 21 March 2011 (UTC)
- I wouldn't say it did almost nothing, see Deepwater_Horizon_oil_spill#Consequences. --Jayron32 03:55, 21 March 2011 (UTC)
- Yes, broadly Chernobyl was devastating and Deepwater comparatively marginal, after all oil is a biological product which degrades in a few years. However in one case there is a government wanting to deny it and move on, a lobby industry to try to downplay it and no one except people too poor to move to care. Interesting that a single NGO medical centre is still treating 200 new children a year for radiation sickness in 2011 [9] whereas based on reliable sources (cough) Wikipedia claims only 237 people have suffered from radiation sickness since 1986. In the case of Deepwater by contrast there is a well funded government and media desperately searching for "animal touch stories" to try to make cash from them. --BozMo talk 06:24, 21 March 2011 (UTC)
- The charity says it's treating children for "cancer and other diseases related to radiation exposure"; this is not the same as radiation sickness. -- BenRG (talk) 10:31, 21 March 2011 (UTC)
- As BenRG notes, there is a world of difference between radiation sickness and diseases (potentially) related to radiation exposure. As well, I do wonder – and this is not to in any way negate the value of the work they do – if there isn't a significant fundraising advantage that the charity enjoys from stating that they treat "cancer and other diseases related to radiation exposure" instead of just "childhood cancer". Belarus has a population of roughly ten million people; even in the absence of any unusual radiation exposure, a few hundred childhood cancers per year wouldn't be abnormally high. The number might be even less remarkable if we knew exactly what "other diseases" were included. (Some very quick searching seems to indicate that there was the expected increase in thyroid cancer due to radioiodine exposure, but that accounted for most of the increase in total cancer rates following Chernobyl. Cancer incidence in most categories appears to be comparable to that observed in the United States: [10]. No increase in childhood leukemia was observed: [11].)
- Incidentally, BozMo, do you really think that there aren't lobby groups and governments who would benefit from denying and downplaying the effects of the Deepwater spill? (When I started to read your comment, I initially thought you were talking about Big Oil and its lobbyists.) For that matter, aren't there well-funded, multinational, media-savvy pressure groups who are very active in publicizing the disaster at Chernobyl? TenOfAllTrades(talk) 13:18, 21 March 2011 (UTC)
- There is a valid criticism of my comparison above since our article just quotes radiation sickness in the immediate aftermath as 237, whereas the chronic stuff is further down the page. There is quite of lot of info on the types of illness in the medical centre but it all needs translating; it looks to me as though chronic radiation sickness is the main problem but I have sent off a few queries. On the fundraising and lobby groups as far as I know this is the only major NGO working in Belarus, and you do not get to be an orphan NGO working in Zimbabwe, Sudan, Israel, Gaza Strip, Somalia etc by saying things which governments don't like. As for "Big Oil" (I left working there 6 years ago) compared to the money vultures in the USA I regard the BP lobbying group as scoring about 0.1 on the Geoffrey Howe scale of savage dead sheep. --BozMo talk 13:42, 21 March 2011 (UTC)
- Yes, broadly Chernobyl was devastating and Deepwater comparatively marginal, after all oil is a biological product which degrades in a few years. However in one case there is a government wanting to deny it and move on, a lobby industry to try to downplay it and no one except people too poor to move to care. Interesting that a single NGO medical centre is still treating 200 new children a year for radiation sickness in 2011 [9] whereas based on reliable sources (cough) Wikipedia claims only 237 people have suffered from radiation sickness since 1986. In the case of Deepwater by contrast there is a well funded government and media desperately searching for "animal touch stories" to try to make cash from them. --BozMo talk 06:24, 21 March 2011 (UTC)
- I wouldn't say it did almost nothing, see Deepwater_Horizon_oil_spill#Consequences. --Jayron32 03:55, 21 March 2011 (UTC)
- BTW an excellent article on the effects of Deepwater and its complicated mix of science, politics, and the media, is this New Yorker piece from a few weeks ago (behind a pay-wall here, but worth tracking down). --Mr.98 (talk) 13:06, 22 March 2011 (UTC)