CaptainPanic

Starting with the last question: sure it could be more complicated. You could make numbers personal (you get to use a different number 1 than me. You get 1(Michel123456), while I get 1(CaptainPanic)... then, if we also keep a history of all numbers we use, each number in the entire world would be unique. It would certainly cause all computers to come to a grinding halt, because of all the extra operations they have to do :) I wouldn't want to see the result of any of the models that I build anymore, which use multiple loops of iterations (millions of calculations). Even without your suggestion, my relatively fast computer needs several minutes to arrive at an outcome... if the result would include a history of all operations, I would go nuts... a calculation would take multiple days, and the result would have such a massive history that I would need a year to read it. But if you write a program, it's possible to keep a summary of the history. So, if you want to do it, it's possible. I don't really see the point though.

I assume that you mean that the nuclear power lobby or the coal/oil/gas power lobby are always objective? [/sarcasm] Regarding the argument about the grid: electricity grids in rich countries are not very much suited for large-scale solar/wind yet. Just like South-Africa, any other country will need to improve/expand the grid.

True, but that is not an argument against those types of power... They should always be included (especially if the thread title asks us to include them). Solar and wind power are becoming more competitive (they are becoming cheaper while other forms of energy are getting more and more expensive). The discussion about nuclear energy is a long-term discussion because of the complexity of a nuclear reactor, so the price-trends and safety records of solar/wind must be considered in the right time frame too (long term). A comparison of nuclear and sustainable energy in the current situation is a fallacy in itself, because the at least 10 years pass between initial planning and actual start-up of a nuclear plant. The time needed between first plans and actual start-up of wind energy is much shorter (1 year?) and solar cells can be placed in a matter of days. It would only be fair to compare nuclear and solar/wind at the same start-up date, not the same day of the first draft plans. That would mean comparing the current state-of-the-art nuclear energy technology vs. solar/wind in 9-10 years from now.

Including solar and wind power?

I think you understood just fine. I think that the ISS has about 8 kW of power, while a full-size nuclear plant can be around 1 GW. That's a factor of 125000, or five orders of magnitude. Those radiators would be massive... and there would be a lot of piping involved, because you need to pump around a lot of water (I'm guestimating that it's about 1 m3/s). I would guestimate that you can radiate about 1 kW/m2 of heat if a radiator in space points away from the sun. So, you would need about 1,000,000 m2 of surface area (1 square kilometer). Pretty big indeed. Providing cooling water for a 1 GW power-unit is always a very large operation... which is why companies like to get cooling water from the sea or a river. It saves a tremendous amount of money. Without river/sea water, they need to build cooling towers, often more than one, which are huge (100 m high) structures.

It takes a while, but can be as short as 5 minutes. Strong coffee has a much stronger effect than Cola. (We call it 'cola' in the Netherlands, which on the other side of the Atlantic often got me a 'soda' by accident because you guys all call it 'coke', and the barman just misunderstood... but that's completely off-topic). p.s. should this be in one of the medical science subforums?

I have the same, but I'm not 100% sure why. Anyway, I think it's quite normal.

Kinda depends how the aliens present themselves, doesn't it? If they present themselves in a tiny village, in the middle of the night, then acceptance might be difficult. If they land on Times Square in broad daylight, then it might be a little faster. Regarding Facebook and alien friends... let's first find out if they also developed language, shall we?

Nitrogen removal is the removal of nitrogen. You really need to give more information. Nitrogen removal is probably denitrificationwhich happens in waste water treatment plants. But it can also be any of the following: - A process where nitrogen is removed from natural gas (also called nitrogen rejection). - A process where nitrogen is removed from crude oil in a refinery (often similar to sulphur removal - and often in the same reactor). This one is not very likely in your case, since nitrogen is not present as ammonia, but ammonia is formed instead. - A De-NOx installation (1, 2), removing nitrous oxides from exhaust gases. Also no ammonia. - Any other process where nitrogen is removed. Take your pick. Probably either the 1st or the 2nd. Waste water treatment or natural gas treatment.

Condensing steam is done at about 100 degrees Celsius, if you keep the pressure at 1 bar (atmospheric). The ISS also uses radiators to get rid of the heat. Still, I do not understand why anyone would want to put a nuclear reactor in orbit anyway (not if the goal is to supply the earth with power).

Agreed. Let the Valence bond theory, or thermodynamics, be your light in the darkness of pseudoscience hell. I have a profesisonal allergy to HHO. (But not to H2O, H2 or O2, luckily).

To all, I would like every one experimenting with HHO generators or what ever you are calling them to look at some thing called thermodynamics.

What I meant to say is that the reactor is inside the spaceship/spacestation. So, the reactor is cooled by the spaceships/spacestation water system, and then the water system cools itself with radiators. You do not want to cool a nuclear reactor directly with radiation...

I love the idea, but you overlook one huge sector of our economy: The real economy would continue. But millions of people who are working in the financial sector would lose their jobs, because the only thing they do is move money around... Which shows that the importance of these financial jobs is overrated.

I'm assuming that this is not some homework assignment (if it is, you're not learning anything from simply getting the answer). Total volume = 2000 (Volume warm water) + (volume cold water) = (Total volume) (Volume warm water) = (Total volume) - (volume cold water) T_final = { (Volume cold water)*T_cold + (Volume warmwater)*T_warm } / { Total volume } And combining two formulas: T_final = { (Volume cold water)*T_cold + ( (Total volume) - (volume cold water) )*T_warm } / { Total volume } And that last formula now has to be rearranged: (Volume cold water) = (Total volume) * { (T_final - T_warm) / (T_cold - T_warm) } If the creek is 8 degrees, and the warm water is 20, and you want to arrive at 15, then you need: (Volume cold water) = 2000 * { (15 - 20) / (8 - 20) } = 2000 * {-5 / -12} = 2000 * {5 / 12} = 833.3 liter cold water A better (long term) solution might be a thermostat and a pump. If the temperature gets above a certain value, the pump will start until the temperature drops below a certain value. (Make sure that whatever shop you get it understands that it's for cooling, not for heating).

Well... in a similar way, you would think that it would be a bad idea to carry highly flammable fuels in an atmosphere full of oxygen. Yet, we do that all the time.

I see few practical problems that we cannot overcome. My main question is: WHY? Why not build the reactor on the surface, if the electricity is needed down here anyway? I think an explosion on take-off is not a major issue. We can build containers that can withstand practically any explosion. It's the heat of re-entry and/or impact that can burn up almost anything... Still, I think we can even design something that can withstand that, and keep a nuclear fuel in its container. Although that is true for the entire spacecraft, it is not true for the nuclear reactor itself. You can have water cooling like any other reactor... and the water must then be cooled by radiation, which is no problem, as long as you point your (very large) radiator away from the sun, and coat its backside (which is pointed towards the sun) with a highly reflective material.

I think we had a rather excellent thread (65 posts, all good quality) on this same topic only last February. Is there anything in particular that you wish to discuss? Otherwise it may be better to simply refer to that one, instead of having the same discussion again? I certainly would simply copy-paste some of my posts. I still think they're valid.

What? SFN will be entering the 21st century as well?

I think that people often allow themselves to get distracted. I know I do - I wouldn't be on this forum if I didn't. If someone is potentially keeping an eye on me, I can suddenly focus much better. Could it be that simple?

This thread is double. It has also been posted in homework.

Actually, I don't think we can really help. The assignment pretty much spells out what you have to do. Start with choosing a higher level programming language. According to answers.com (not the best source, please doublecheck) ten examples are: * Java * C * Python * Scheme * Prolog * C++ * C# * Java script * Lisp * Ruby Please ask more specific questions for more specific help.

Based on what? In principle, more stages means you can achieve a higher speed. If you have a theoretical spaceship carrying its own fuel, and capable of reaching 1/3rd light speed, then I can attach another stage to it, and you bring your spaceship to, say 1/6th of the light speed. Then you can ignite yours, and since you already have some initial speed, you should get to more than 1/3rd light speed. Or is a stage not considered "carrying its own fuel" anymore?

Although free speech in itself is a good thing, I think your argument is wrong. Firstly, there was no such thing as free speech in 1517. The RC church determined what was allowed and what not... and they excommunicated Luther for his actions. That means he was not protected by the law, he enjoyed no such thing as free speech, but he still wrote his text. Secondly, there are many revolutions which started because some inspiring people broke the law. A black woman refuses to sit in the back of the bus. Is this a good argument for anarchy? Breaking the law apparently makes society more advanced, why shouldn't breaking the law be allowed then? See, your single example is not an argument for free speech. Thirdly, you suggest that we would advance through free speech... then why is it that in 2011 we seem to have gotten absolutely nowhere? The discussion is still at the level of 1517, if not worse. People still debate which religion is right and which is wrong... and it's not even a critical movement within a specific religion, but it's just the religious factions criticizing each other. Fourthly (don't worry, I won't go up to 95), the formation of Protestantism was not the milestone... but the coinciding Age of Enlightenment was the milestone. And that Age happened not only in the Protestant regions, although Protestant regions were the birthgrounds of some of the oldest universities in the world. And finally, there have also been many pointless wars which were started because of (free) speech. Hitler exercised his free speech by writing Mein Kampf, which is one of the reasons that WWII went the way it went. And that resulted in many technological breakthroughs. Good argument for free speech? I somehow don't think so... Free speech is only meant to prevent governments from repressing a population, but free speech should be used by a population with care. Before you know it, the free speech of one person represses the freedom of another. For example, in my own country (the Netherlands), there are politicians who constantly exercise their freedom of speech, but they use it to suggest that we ban (make illegal) the Quran... in summary, that's using your freedom of speech to make sure that others don't. That's not what the freedom of speech is meant for.

Companies they adhere strictly to regulations... which is why governments much make laws and regulations, to force companies to be clean. And that's exactly the point of this thread: new regulations to make the world cleaner. The regulations must come from governments. No regulations would mean that there would be no (successful) lawsuits from environmentalist groups either. It's ridiculous to suggest that the incentive to be clean lies with the corporations. They are the ones who generally oppose stricter regulations.