CaptainPanic

http://www.google.nl/#hl=nl&q=ferrous+ascorbate+water&meta=&fp=4cb2eba39722ca42 http://www.google.nl/#hl=nl&q=ferrous+ascorbate+solubility&meta=&fp=4cb2eba39722ca42

I specifically need the heat capacity of ethanol/water mixtures at various temperatures and pressures (all concentrations, from room temperature up to >200 deg C)... I'd like to learn how to calculate this myself but "Excess properties" (like the Excess Gibbs energy and excess enthalpy that you find in the thermodynamics textbooks give me a headache). In addition, I have a feeling that the beautiful thermodynamics theories are not of much use because the ethanol/water system is highly non-ideal (but I might be wrong here). Does anyone simply have a source (books are also fine - just tell me the title + author/editor) where stuff like this is listed? I'd rather work with measured data than some horrible integration or other maths exercise

I got as far as level 21 (in a couple of minutes)... and got bored. We're a demanding bunch here at SFN - it it ain't as difficult as rocketscience, we're bored.

Correct me if I'm wrong, but it looks like olweiser doesn't want to say what he needs this heating system for. That's a pity... and this makes it really difficult to help. We already explained several times that what he wants is nearly impossible. Anyway, let's crunch some numbers to show it again: Let's just assume we're dealing with a very standard liquid-liquid heat exchanger for water (heated also with hot water). The typical heat transfer coefficient is 1000 W/m2K (see for example: Perry's Handbook 7th edition, 11-25). We want to find out what temperature difference is needed to achieve 67 kW in 30 cm2 (or 0.003 m2). Formula: [math]P = U\cdot{A\cdot{\Delta{T}}}[/math] with: [math]P[/math], power, in [math]W = J/s[/math] [math]U[/math], heat transfer coefficient, in [math]W/m^2K[/math] [math]A[/math], surface area, in [math]m^2[/math] [math]\Delta{T}[/math], temperature difference, in [math]K[/math] (or Celsius - it's a temperature difference) so: [math]\Delta{T} = \frac{P}{U\cdot{A}}[/math] [math]\Delta{T} = \frac{67000}{1000\cdot{0.003}} = 22333 K[/math] That means that your outside heating must be hotter than the surface of the sun... (sun = 5,780 K (5,510 °C), and you need 22,631 K (22,358 °C)) And that's what insane_alien meant when he said: Stop looking for "someone (perhaps someone here?) who I can work with to create this", and start thinking about plan B.

Why is socialist: 1. Spelled with a capital letter 2. An insult And can anyone link to a genuine website that is written in a style that shows that Socialism is bad... I'd be very interested in that, because if Obama is already a socialist, then I guess I pretty much voted for Lenin himself at the last elections. Definitions are different on both sides of the Atlantic. In Europe being called "social" is a compliment... and the "socialists" are in many governments.

Seams like the auther of teh tekst shoed also take Obama's message's at haert: stai in skool end work hart. Then again, I guess that Obama didn't replace the entire staff last January. Could be a remnant of the Bush era. (After all, you don't want a simple webmaster who's smarter than the president, right?)

Why can't members just read, without posting? What good is a message to encourage people to post? It has a benefit to login, even if you don't wish to post: - You get your own layout (anything under "My Account > Thread Display Options). - You can happily click on the "did you like this post?" thingy. - You can make friends, and maybe send personal messages - You can report spam I don't see why people should post. Some people are passive when watching TV. Apparently, some people are passive even when reading a forum. And why not?

I realize that I say nothing new, but wikipedia has lots of information. It also has references at the bottom of most pages that guide you to additional information.

Aaaaahhh.... Media reports about incidents, makes stupid conclusions and goverments/organisations follow by making stupid laws/rules. Some people seem to think that safety should be the primary goal in life. That any avoidable death or injury should be avoided at all cost... Preferably by making something illegal, and demanding that the already overworked local police squad check everybody. Great. This won't work. It is not possible to create a society where the individuals have no responsibility for their own safety and the safety of those around them. And since this is impossible, why are we even trying? Can somebody just start suing the media for spreading terror among the population please? Damn, I'm not sure about the rest of the world, but the Netherlands has never been as safe as it is now. Yet we keep getting new laws that restrict us... generally speaking, these laws cost a lot of money, and might avoid one or two deaths per year. Sorry, that means they're not worth it. You cannot tie all the stupid people down because they might kill themselves. You cannot outlaw all sharp objects because they might become a murder weapon. And about the knife violence. Yes, some streets are dangerous in the UK. Yes, knife crime went up (actually, I haven't seen any statistics). At the same time, other crimes went down. The amount of murders per year remained nearly constant. Why are people so terrified? Why is the UK becoming such a police state? There is no point. Why don't we invest all this money in cancer research? I'm sure that would avoid a lot more deaths... deaths that are equally random and sad.

1. It's a pump. It probably has pistons moving that cause the thumping sound. I can't remember the name of such a pump right now. 2. Depends on the mixing, as you already guessed. With no information, I just have to guess that (1) it's a special kind of detergent which greatly increases surface tension, and (2) they have a very nice mixer (high rpm) with good aeration (meaning they have plenty of air). Actually, the stuff that's used in the 1st movie and the 2nd movie don't look like they're the same substance. To me, the 1st movie looks more like they're pumping paper pulp, while the stuff in the 2nd movie is clearly a foam.

I meant soil, sand, whatever. You can put it in concrete and it'll still work. The only reason you stick it into something like soil is to keep it upright (so that it doesn't fall over). So, how deep? Depends a bit on the aluminium pipe, doesn't it? If you have a 300 meter TV tower, I would suggest you put it quite deep. If you have a 5 meter pipe... You'll know better how deep to bury it. Depends on the soil. Depends on the pipe. Depends if you use any other tricks to keep the pipe standing (like ropes). Don't worry too much about conductivity. If you have a metal pipe, the conductivity is always good enough. Soil itself conducts also pretty well (especially if it's wet - anything except desert basically). My main concern would be safety. If you catch lightning... make sure you're in a safe place yourself.

So... people in caves plotting against America: bad terrorists, let's send 130,000 troops. People already living in America, disrupting important communication lines: just dumb, perhaps consider to send the cops? How come these people aren't being waterboarded? Excuse me for throwing more oil on a fire here... but these kinds of ideas aren't the kind of ideas you want to spread in the country. This is just as freaky and fundamentalist as some of Bin Laden's ideas... and a lot more dangerous. If these guys plan to knock down everything that sends radiation at us... they will disrupt the entire planet, and they might even block the sun (I really hope that nobody told them that the sun is a source or cancer)!

I'm curious how much more the negative rep will be used (relatively) in the politics subforum than on other forums. (Not sure if the mods can monitor that though).

Pure capitalism, in its extreme like we've seen over the last decade is indeed nearly as evil as communism in its extreme like in the Soviet Union. I really liked the documentary "The Corporation", that explores companies... and in a way also our capitalist system. The answer to the question is quite shocking, but not very surprising. Personally, I'd like a good portion socialism, a bit of capitalism to reward the good people and all under a democratic sauce of liberty. Thanks. Who could agree with any system that just sees people as a commodity that you can use and dump at will? That's what capitalism is. You don't need someone? Just fire him. We're talking about people here - not some lumber or iron ore.

Yeah, but while Obama is the one giving the lesson, Bush was actually at school to learn to count to 10. You can't compare the two. I can imagine that if you're an unemployed dropout yourself that you don't want a socialist president that encourages your kid to go to school [/sarcasm] Then don't tell them that a lot of their (European) allies that help keep their white American ass safe are socialist countries. This attitude is known as "American arrogance": wave the flag, and do whatever you want. "Whoever isn't with me is against me". (A statement that apparently can be reversed too: "if I didn't vote for the president, he must be against me"). It's been the standard American foreign policy for 8 years while Bush was in power. The boss showed how it's done - it's not surprising that some people copied the attitude. When people stop communicating... the next step usually is... ?

And here's the link to the rest: http://www.spiegel.de/international/zeitgeist/0,1518,644296,00.html I wouldn't mind to have an output only: me controlling a computer with my brain. It'd surely prevent repetitive strain injury. But I'm scared of the thought of the input into my brain. We have evolved important filters over the last million of years: filters that for example chimps don't have. We might just bypass a whole bunch of important filters if we start playing with this kind of technology. An overflow of information really will not make you more intelligent. In fact, it's the filters we have that make us so intelligent. Chimps have a better access to information ( - apologies for not searching for a better quality movie)... but it's humans that are more intelligent.

And from the (scam) website: Adding the two quotes together: according to J.C.MacSwell, this process would come to a halt in about 1 second. Which is 1 second longer than I predicted. I'm not sure that I understand the principle of the process that J.C. explained there though. What is 1 cycle? (Because my point is that the cycle isn't a true cycle: there is just a proposed heat input, but no output, therefore no Carnot cycle, and no spinning turbine).

Forget it. As insane_alien already said: it'll be too big to use the sun. And the energy in the flow of the water itself wouldn't even heat it by 1 degree C. You need 67 kW, and even in a best case scenario you need 30 m2 of heated area to get that from the sun. You might be able to concentrate that sunlight onto a very small surface (with shaped mirrors)... But your next problem is that this small surface is 10 cm of hosepipe. If you plan to build 30 m2 (or better a lot more) mirrors or solar boiler, perhaps it's easier to simply expand the size of the hose and make life simpler. So, since we mythbusted that you can heat up 0.25 liter/s of water in 10 cm plastic hosepipe using the sun, and we also mythbusted the idea of using that hosepipe - perhaps you might telling us what the whole thing is all about? Then we can help you properly. You might have noticed that there are plenty of people who are willing to help, and even to pick up a calculator and do (some of) the maths for you. Now it's time for you to help us. Write a long post to explain what this is all about. Please

Ok, Monday morning, it's a bad idea to do thermodynamics before finishing my first coffee, but here it goes. It's certainly a scam (coffee or not, I can recognize stupidity). Kender Solar Energy is a scam (<-- remark for Google hits). The system is essentially an open system with a turbine and a compressor. That simply means that the system has 2 areas with a different pressure. There is the entire heat exchanger and Helium storage, which should be entirely at 200 atm. And the little part between the turbine and the compressor is apparently at 20 atm. Now, laws of thermodynamics (before or after coffee) say that even in an ideal case, the turbine will generate at best the same amount of energy as the compressor needs. There is no heat exchanger between the turbine and the compressor... so, the two steps (expansion and compression) are two equal but opposite steps. They seem to suggest that the pressure after the compressor is not yet 200 atm (the pressure "builds up in the heat exchanger"). That means it would not work. If the heat exchanger is an open system (in its essence it's just a pipe), then the pressure is the same along the entire heat exchanger. This idea might just work if you have a set of valves which are controlled by a measuring system that can open them and close them. As a continuous system, I fail to see how this can work. You also will need a cold sink (a place to dump your heat). Carnot says that no cycle will run at 100% efficiency. That means that every Joule that isn't converted to electricity will become waste heat. Waste heat must be dumped. Finally, if this is a continuous process... why do they add this helium storage (the storage won't become mre or less full... so why not leave it out altogether)? And why don't they just use nitrogen, which is more dense and (I believe) will carry heat a bit easier? I'll read this again later. Feel free to correct my early morning thermodynamics. I got a feeling that it's correct though [edit] 39 kW from a (0.8*2.5 = 2 m2 area???). The sun provides about 10 times less even in the best circumstances. Just forget about this scam... If you want to make electricity from the sun, use either a solar cell, or go with a simple steam cycle (invented by Mr. Watt in 1745). Here's a picture of it. Just replace the boiler by a solar boiler. [edit 2] I finished my first coffee, and I still think it's a scam.

Yeah, good point insane_alien. I'd like to consciously choose when I send and receive any data... Knowing the commercial world a bit, you'd soon be sued for whistling a tune which is copyrighted by the music industry. Current internet technology is absolutely not suited to be connected to my brain... also not with a heavy firewall in between.

How fast is the water running? How warm does it have to be? Depending on those two questions, and on the surface area of your 10 cm hose (what's the diameter), you can calculate how many watts of heat you have to deliver per surface area. You're looking at a classic heat exchange problem here... and it can always be done. Whether it's practical is another issue. You could for example put a second (wider) hose around it and fill that with hot water. That will heat the inner hose and therefore the water. Then you heat it with hot water (which itself was heated by electricity or gas). You get better answers if you describe why you want it. That will limit us in our solutions. Can you adapt those last 10 cm of hosepipe and make it wider for example? Or do you have to heat it through the plastic of the pipe?

I'd like to emphasize and add to two things that hermanntrude already mentioned: 1. Safety of any material can be checked in the MSDS (Material Safety Data Sheet). These can simply be found using Google. Make sure to check more than one: the MSDS for fine tin powder is different than for a single lump of tin (because one can form a dust cloud, and a single lump can't). 2. A tin can is not made of tin.

You're right. We're talking about development of a new type of turbine... so we shouldn't compare this with two small ones, but with one bigger one (twice the power output). With wind turbines, it seems that bigger is always better

Cool video! Even if you try it 50 times... a human body doesn't always have the same friction going down a slide... and no way that you can have the same speed at the end of the slide twice in a row (unless you're just lucky). And therefore, the landing is rather unpredictable. If you have ever gone down a water slide, you know that you go (much) faster when you have very little contact with the slide itself (touching the slide only with your elbows and heels for example). And to miss that little pool, you only need a very small difference in your final velocity. If you have a special sledge to sit in, on a track... then perhaps the jump can be repeated. But just an ordinary human body in a wetsuit (why the wetsuit?) cannot go down twice the same way.