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John Cuthber

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Everything posted by John Cuthber

  1. The chemical and microbiological specifications for tap water are generally more stringent than for bottled water.
  2. Actually, those processes are (by the laws of thermodynamics) driven by a net reduction in organisation in the universe. It's true that trees grow, but it's also true (and a necessary part of evolution) that trees die. The expectation is that the universe will end up cold dull and empty. Your problem is only looking at yourself and the things near, and like, you. We may be getting more complex; so is life. But the universe isn't.
  3. Long ago, at school I really pissed off the metalwork teacher. He had just finished explaining to the class about pickling copper after annealing it. You wash it in 10% sulphuric acid to remove the oxide film. They also pointed out that you had to use the special brass tongs because the acid would damage the (usual) steel ones. And, of course, he made a big song and dance about being careful with the acid. It undermined his authority when i just took stuff out of the bath with my hands and rinsed it under the tap. Dilute sulphuric acid does attack normal human skin, but slowly. Washing your hands in it is stupid bravado (and yes, that applies to me doing it when I was a school kid) but it doesn't imply any superhero skills. I doubt I ever got through a gallon of coffee in a day, but when I was a student I was getting through half a dozen caffeine tablets with my breakfast. Lethal doses of caffeine taken rapidly- are of the order of 5 grams. A cup of coffee is of the order of 0.1 grams. So, 50 cups of coffee at once would kill you . But a gallon over the course of a day is just an expensive (and unhealthy) choice of drinks. One obvious effect would be an extra gallon of piss every day. That's rather a lot. Enough, for example, to wash out a lot of any medical drugs you took before they had time to work. So the idea that it takes 4 times as much medicine to have an effect isn't a miracle either. There's nothing here to investigate.
  4. "What is the best political direction?" Neither- if you go too far.
  5. Most of the people in the UK didn't vote for him or his party.
  6. I once got asked to analyse the stuff found on the inside of a burst gas cylinder. They were trying to work out what had happened. There had been a witness- very very briefly- but he wasn't telling us anything anymore. (re)filling high pressure cylinders isn't as easy as people thing. It's also often illegal. This is not the sort of thing to do with "string and sealing wax" as the phrase goes https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10309/1030908/Whatever-happened-to-the-string-and-sealing-wax/10.1117/12.2283713.short?SSO=1
  7. I think they value it; they just don't recognise it. To be fair, they have seen few examples.
  8. Watch this space. https://hydeploy.co.uk/faqs/what-is-hydeploy/
  9. Which bit don't you understand? This https://en.wikipedia.org/wiki/Nernst_equation which says the voltage depends on the pressure, or do you not understand the idea that you can store gas at constant pressure in something like this? https://en.wikipedia.org/wiki/Gas_holder Since the gas pressure never changes, the gas is never compressed, no work is done compressing it. That's why the voltage is higher.
  10. He pointed out that it's impractical. "Liquid hydrogen must be contained at incredibly high pressure or maintained at very low temperatures by complex cryogenic systems. " As far as I can tell, only space rockets use LH2 as a transport fuel- and even they sometimes shy away from it. I don't know of any serious project that is looking at LH2 as an energy storage medium . There are two reasons. 1 it's hard. 2 It's inefficient- you waste a lot of energy cooling and heating it. The thread is about an new trick in the process of making hydrogen; what you do with it after that is a separate issue. Incidentally, If you generate the gas electrolytically, the answer is "none". You don't need to do work compressing it; the reaction will still work at higher pressure but needs a slightly higher voltage. Hydrogen generators exist, so they are clearly "reasonable"
  11. Nobody said you did. But you did raise the equally irrelevant liquid hydrogen.
  12. Well... pretty much the same as a petrol tank. And there are plenty of 25 year old petrol fuelled vehicles on the road. They aren't all suddenly exploding, are they? At most, you need to add another line to the MOT test "leak test the tank". And LNG boils at about -162, and nobody is considering it as a transport fuel either. Why did you raise the issue? They never did. That's why we have regulations.
  13. Those were not incidents involving hydrogen. Hydrogen has one property which makes it rather more hazardous than natural gas- it has a very low ignition energy. On the other hand, the low molecular mass and comparatively low energy density (a litre of hydrogen carries less energy than a litre of methane) tend to reduce the risk. to exactly the same extent that it will leak through a badly made connection, it will also leak out of the area it is released into. There's a story of a demo where they emptied a tanker truck of liquid hydrogen onto the surface of a lake, waited 5 minutes and struck a match. They then invited anyone to do the same with petrol/ gasoline. Any fuel is, ipso facto, potentially dangerous. The way round that it to not let it escape. Not really. Once you tighten up the fittings so that the metal meets the metal, there's no hole. Practically speaking, Hydrogen won't diffuse through a mild steel pipe any more than propane will
  14. They typically use CuCl. Almost certainly not an organic dye. The tubes are typically coated on the inside- much like an ordinary fluorescent tube. That's a rather aggressive environment. These are more likely. https://en.wikipedia.org/wiki/Phosphor#Standard_phosphor_types though just painting a clear lacquer onto a white tube would work, as long as it was heat resistant enough.
  15. The emission spectra are changed slightly by a magnetic field. https://en.wikipedia.org/wiki/Zeeman_effect But the effect will be too small to see unless you have a tremendously strong magnetic field. The commonest use of copper chloride in this way is in fireworks. The colors of most modern fireworks involve a few metal chlorides, which fluoresce strongly in the visible wavelengths: Barium chloride produces green; strontium chloride produces red; and copper chloride produces blue. https://cen.acs.org/articles/95/i27/s-fireworks-produces-those-colorful.html But it's also used in lasers https://www.repairfaq.org/sam/laserccb.htm
  16. You don't seem to know what inbreeding is. That does not seem to be your only area of ignorance.
  17. They are the same as reindeer (note the spelling, btw). Caribou have been semi domesticated for a long time. Not sure there's much advantage over a horse.
  18. I love the advert for the stuff at the end of that page- particularly this bit "and it has a myriad of applications."
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