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exchemist

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Everything posted by exchemist

  1. This seems awfully garbled not to have much to do with the topic of the thread. 1) Temperature is a bulk property. An individual atom does not have a temperature. If you think you have read that it does on Wikipedia, I feel sure you have misunderstood what you have read. If you can provide a link perhaps I can explain what it is actually saying. 2) E=mc² has got nothing to do with the topic under discussion. 3) The Perfect Gas Equation, or Ideal Gas Law, has nothing to do with the topic either. Firstly the question is about metals, and secondly, the effect of temperature on pressure and volume has got nothing to do with how radiation is absorbed and causes a rise in temperature.
  2. The term “nootropic” does not seem to have a properly defined meaning and is often abused to promote agents and supplements of doubtful utility. Caffeine seems to work, for many people.
  3. Explain in your own words what this “law of vibration” is, please. Nobody is going to waste their time watching crappy YuoTube videos.
  4. Can you give examples of what you mean by dye "quality", e.g. good and poor quality? I was under the impression the issue was how the dye was fixed.
  5. I doubt it. Expansion is not a physical system. A physical system has to comprise matter, radiation or fields of some description, I think. As I understand it, the Big Bang hypothesis suggests radiation and maybe (?) some elements of matter were present at a very early stage, but since the laws of physics break down as one extrapolates back towards the presumed singularity (if there was one), it's probably a bit meaningless to speculate too much.
  6. You can’t have an expansion of energy. Energy is a property, not an entity. Energy has to be the energy of something, a physical system of some kind.
  7. Surely an explosion is a rapid expansion, in volume, of matter, isn’t it?
  8. It is not only bound electrons that absorb radiation. That is true for electronic transitions, absorbing light in the visible and UV range. However IR and microwaves stimulate vibrations and rotation, respectively, of polar molecules. So long as you have a degree of charge separation, you have in principle something that can couple to radiation, if the scale and frequency are right. But I think you must be right that to explain a temperature rise we need to account for how the nuclei are set in motion, in the form of lattice vibrations. A mere sympathetic oscillation of the conduction band electrons setup by the radiation will generate reflection rather than absorption, it seems to me. And of course metals are good at reflecting radiation. So I think we need to look at the interaction of electron motion with lattice vibration. It feels to me as if this is connected with the mechanism behind electrical resistance in metals. There has to be a process whereby coordinated induced motion of electrons is converted into randomised motion of electrons and vibrations of the lattice. But I don't know the relevant solid state physics.
  9. Not at all. That was asking about routes for commercialising a utility model (petty patent), e.g. toll-manufacturing vs. licensing, who bears the commercial risk and so forth, which are perfectly reasonable issues to discuss. This time, the post is asking us to put a commercial value on something we know nothing about.
  10. What a ridiculous question. “I have something in this bag which I will neither show you nor describe. Please tell me how valuable it is.”
  11. I think it is harder to explain for a metal than for a molecular substance. In molecules, there needs to be a dipole for the electric vector of the radiation to couple to, which excites vibrations in the molecule. For example, nitrogen gas does not absorb in the IR as the molecule has no dipole, whereas water vapour does, because the hydrogen atoms carry a partial +ve charge while the oxygen atoms carried a partial -ve charge. In a metals there is a lattice of +ve cores and a sea of surrounding delocalised electrons. Lattice vibrations (phonons) can presumably be excited by the +ve cores coupling to the electric vector of the radiation, but I'm guessing a bit as I never covered the relevant solid state physics at university. Perhaps someone else can comment further.
  12. I thought this article in the Guardian was rather intriguing: https://www.theguardian.com/science/2024/mar/09/controversial-new-theory-of-gravity-rules-out-need-for-dark-matter As I read this, the proposal is that fluctuations in spacetime itself (i.e. not vacuum fluctuations) could give rise to "extra" apparent gravitation which could dominate over conventional gravitation at long range, thereby accounting for the anomalous rotation rates of the edges of galaxies. Link to abstract of the paper here: https://arxiv.org/abs/2402.19459 There was a previous piece on this a few months ago which I missed: https://www.theguardian.com/science/2024/mar/09/controversial-new-theory-of-gravity-rules-out-need-for-dark-matter Abstract of the paper here: https://journals.aps.org/prx/abstract/10.1103/PhysRevX.13.041040 This comes from a group at University College London. They add the caveat that this hypothesis need further work - and some means of testing. (I see Carlo Rovelli has taken a bet at 5000:1 that it goes nowhere, though!)
  13. I ran my 3G iPhone, the original Jonathan Ive design, until last year. I replaced with the smallest modern iPhone I could get (SE), which is still a bit too long to be ideal but better than the others. I do most of my internet stuff on the laptop or iPad, not the phone, so I have no use for a large screen on the phone.
  14. Get the smallest you can. Then there is some chance you can the damned thing into a pocket.
  15. I am not sure what this means. Can you give an example of the kind of copper object in question?
  16. The UK NHS does keep such a record, though I don’t know how reliable it is in all cases. There’s nothing “mandatory” about it for the citizen, but everyone has an NHS number and a medical record which in the past followed them from doctor to doctor when they changed location and registered with a new local doctor. Nowadays it is computerised.
  17. Blimey! Do they polish their sidecars on a Sunday afternoon, then? 😄
  18. I would expect it to be the same mechanism, just in 2 stages, with an alkene as the intermediate step. In both alkynes and alkenes you have π-bonds which can bind to the metal surface. Kinetically, I imagine it may be a bit faster for alkynes, as they can approach in any orientation and still bind to the surface. There are descriptions of this on the internet. Here is one: https://www.masterorganicchemistry.com/2011/11/25/hydrogenation-alkenes-palladium-on-carbon-pdc/. This link suggests that alkynes are more readily reduced than alkenes. The only respect in which I think the mechanism you have drawn may not be quite right is that, according to my understanding, the alkyne or alkene itself binds to the metal via its π-bonds, whereas you have shown the molecule staying above the H atoms, rather than binding to the surface itself before reacting. (There is a diagram of the mechanism in the link.)
  19. On the contrary, a measuring device sees electrical activity in particular parts of the brain, when particular types of thinking take place. See for example this paper on music: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618809/. This kind of work strongly suggests thoughts are due to such electrical activity. The rest of your post seems simply to be arguing that human beings are capable of thinking about abstract concepts. We have a word for that: abstract. As for "inner voice", what is that? I sometimes talk to myself without speaking the words. Is that all you mean? If so, it is just a process of conscious thinking, rendered into words so that I can rationally follow and audit the process of thought. I do it when I am making sure my reasoning is sound, e.g. when working with electrical wiring, or doing an algebra problem. I do not see why this need be anything more than a form of electrical activity that happens to engage the "language programming" of my brain.
  20. It is you that is asserting there is such a thing as a mental "space". The rest of us could be forgiven for not understanding why you call it a "space". That word immediately creates connotations of a dimension. It is not obvious that that is a helpful way to think about the subject, for the reasons pointed out on this thread. Surely the cognitive processes of the brain can be thought of as its activity, rather like the operations of a computer? Consciousness can thus be seen as an activity, not a "thing". This way of thinking about it has at least the merit that electrical signals can be detected in the brain to show there is activity, activity which for example stops when someone dies. Why the need to treat it as a thing, existing in some unobservable "space"? That seems to me to be a category error, albeit one with a long and distinguished history.
  21. Actually not that much becomes converted to ammonium and hydroxide. Most of it is still NH3(aq) : https://en.wikipedia.org/wiki/Ammonia_solution As I recall, ammonia is not much of a reducing agent as it can't give up electrons easily, only share them in a covalent bond, as in H3N:->H+ . (If it actually reduced H+, hydrogen would be evolved.) But yeah it's easy to get in a muddle with Lewis acids and bases. It's one of those concepts I tended to dodge, not finding it awfully helpful on most occasions. No I don't think so. Sugars have hydroxy groups on them that can be protonated in acid conditions, i.e. R-OH + H⁺ <-> R-OH₂⁺ , but they are no more liable to be protonated than a water molecule, i.e. H₂O + H⁺ <->H₃O⁺, so that won't raise the pH. (While sweet substances make acidic substances taste less acid, they do not do so by neutralising the acidity. It's just a trick of the taste buds.)
  22. Not necessarily. For example, some cations form complexes with OH-, thereby causing water to release H+, acidifiying the solution. Both in the case of ammonia and in the case of metal cations such as Al 3+, water is caused to split, by abstracting either H+ in the case of ammonia or OH- in the case of Al 3+, leaving behind extra OH- or H+ respectively and thus altering the pH of the solution.
  23. Think of ammonia. It does not dissociate appreciably in solution but accepts H+, causing water to dissociate, and thereby raises pH. Stomach acid has a pH ~2, so has plenty of free H+. I can't see why this would in itself cause other substances to dissociate, though protein dissociation is catalysed by enzymes in the acid environment of the stomach, I believe.
  24. All you are saying is that science is a method which, like many things, is an abstract concept. Nobody would deny the usefulness of abstract concepts. Mathematics is abstract, and you can't do some sciences at all to any degree without maths. What you are demanding seems to be something different: the existence, not of an abstract concept but of an extra dimension. This implies that objects can be situated along this dimension and assigned intervals, relative to one another, in terms of it, by some kind of measurement.
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