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exchemist

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Everything posted by exchemist

  1. Yes I too saw that fairly uninformative news article. There is no "before and after" diagram or aerial shot to give any clue about what may have happened. It is normal for meanders, for instance, to become increasingly extreme until the river breaks through, leaving what is known as an "oxbow lake" in the dead meander. But it doesn't look like that here. There isn't enough information to comment. But this doesn't seem to me to have anything to do with the thread topic.
  2. It doesn't make sense to me either. Cargoes from where and going where?
  3. That's stupid. There is no "signal" from a telescope to tell you it is emitting energy. And I'm reporting this as it looks like yet another thinly disguised re-run of your previous threads.
  4. What would a -ve signal from a telescope look like? Radiation intensity is the square of radiation amplitude, isn't it? How can you have a real -ve square?
  5. The arch-debunker Mike West has different figures from Sabine's, with a far higher estimate of people engaged in work that might be thought in some way sensitive: about 700,000. So he says 10 deaths is well within expectations. His comments are a bit buried in this longer BBC article about this issue: https://www.bbc.co.uk/news/articles/cwyw9rpdl4po The quote is as follows: "The US Top Secret-cleared aerospace and nuclear workforce is ~700,000 people," science writer, investigator and pseudoscience debunker Mick West wrote on 16 April on his Substack. "Ordinary mortality over 22 months predicts ~4,000 deaths, ~70 homicides, and ~180 suicides. The list has 10 … The deaths are real. The families' grief is real. The pattern is not." This looks to me like just another of those American panics. I'm reminded of James Thurber's "The Day The Dam Broke"
  6. This seems to be a complete non sequitur. That energy is not an intrinsic property of an object is like pointing out that an object's velocity is not an intrinsic property. It is obvious that neither statement has any implications for the nature of the Big Bang, or (which is a different thing) the origin of the cosmos. You seem to be using this as a pretext to insert into the thread, quite arbitrarily, some unrelated metaphysical idea. Why? And please, please, do drop the crap about "frequency". It makes me suspect you are trying to work your way round to peddling quantum woo, Deepak Chopra - style. 🤪🤡🙃🫖
  7. I suspect the key to your question is in the term "vertebrates", more strictly these days called "chordates". The common body plan you mention is due to evolution of all chordates from a common ancestor, an early fish-type thing. The legs evolved from fishy fins. Fish, amphibians, dinosaurs, modern mammals are all in the chordate family, having the same basic body plan. So that's why. But in fact there are a lot more alternative body plans in the animal kingdom than just the chordates and the arthropods that you mention (insects, crustaceans and so forth). Both athropods and chordates are examples of a "phylum", which is a biological classification based on the basic type of body plan. A few examples of other phyla would be molluscs (shellfish, squid, octopuses etc) echinoderms (starfish, sea urchins, with 5-fold radial symmetry) and annelids (segmented worms). But there a lot more besides. You can read more here: https://en.wikipedia.org/wiki/Phylum It is true that all the large, land-dwelling animals are chordates, which is why you can get the impression that the majority of animals have the same body plan. But if you don't limit your consideration to size, or to dwelling on land, you get a very different picture, with a lot more variety.
  8. According to Wiki, Hegseth thinks (probably rightly and along with the rest of the Pentagon) that these Trump Class battleships are an idiotic distraction, whereas Phelan, who is thought to be particularly close to Trump, is a great proponent of them. (I wonder if it may even have been Phelan who suggested the idea of them to Trump, as a way to curry favour.) It makes me wonder if Hegseth has fired Phelan before Phelan can whisper in Trump's ear and get Hegseth fired! So a Kremlin-style struggle so that Stalin executes not you but the other guy. But if Phelan is that close to Trump, firing him is taking a risk.......
  9. Saw quite a good aphorism on another forum: MAGA are people with Stockholm Syndrome who don’t know where Stockholm is.
  10. Because a -ve "real" number squared is +ve, as you point out, there is no way the square roots of -ve numbers can be "real" numbers. For example what is √-4 ? To deal with this, back in the c.17th, it was decided to invent a square root of -1 and call it i. Once you have that, you can say that √-4 has a value of ±2i. Numbers like this with i as a factor in them are called "imaginary" numbers, as opposed to 'real" numbers. Numbers can also have both real parts and imaginary parts, e.g 1 +2i. Such numbers are called "complex" numbers. Graphically, you can plot the real numbers along a horizontal line, with zero in the middle, -ve numbers extending to the left and +ve numbers to the right, to form an 'x' axis. Imaginary numbers however would be be plotted at right angles, vertically, as if on a "y"axis, with +ve values upward and -ve values downward from the central zero. A complex number like 1+2i, with both real and imaginary parts, would be located on the graph 1 unit along the x axis to the right and 2 units up the y axis from the central zero or "origin". (Such a graph is sometimes called an Argand diagram, after the Frenchman who devised it.) Although one might at first think the notion of defining i is perhaps a bit silly and pointless, the fact that you can plot complex numbers on a graph in this way turns out to make them enormously powerful as a tool in mathematics and science. You can represent one on the Argand diagram as a line drawn from the zero (origin) to the location I have described. This line has a direction and a magnitude. It is therefore a vector, with real and imaginary components at right angles to one another. You can also define it in another way, by the length of the line and the angle that it makes with the x axis. If the length is r and the angle is 𝜽, the complex number can be written as r(cos𝜽 +i sin𝜽), where rcos𝜽 is the x component and rsin𝜽 is the y component. It turns out that angular representation opens the door to a host of applications in physics where there is "sinusoidal" periodic motion e.g. waves or the theory of alternating current in electrical circuits. There are also many connections in maths too, involving exponentials and so on but that's another story. So that is why imaginary numbers are such a fruitful idea, even though they may at first glance seem crazy and just a mathematical curiosity. (P.S. I write this as a chemist, not in any way a mathematician, so the way I express this may not be rigorous to a mathematician. It's just how I think of it. Actually, it was learning about complex numbers in the 6th form at school that first made me begin to enjoy maths. I just thought they were so cool in what they could do and how many areas of maths and physics they are able to link together.)
  11. Right. So either this is another "dead cat" tactic by Trumpy Republicans to distract and confuse the public, or they have been infected by the paranoia that the Trump administration likes to cultivate and actually believe it. What a waste of time.
  12. What's the evidence this is statistically significant? Could it not just be the normal incidence, given the size of these research programmes. Hofstadter's "paranoid style" in Right wing US politics was identified over 50 years ago. It is currently in the ascendant under Trump, who has encouraged conspiracist thinking as part of his drive to gaslight and bamboozle the public. We've just seen Trump announcing he's releasing a load of UFO "files", which is another load of distracting codswallop designed to make people distrust "elites", suspect conspiracies - and look in the wrong direction. In such a climate, it is any wonder that a Republican politician starts yet another hare running? It could either be a deliberate ploy or simply genuine concern on his part, if he has himself become paranoid enough as a result of all this conspiracist campaigning.
  13. exchemist replied to DrmDoc's topic in The Lounge
    Possibly, though I’m not sure why it would be an advantage. But yes I remember dismantling and tuning SU carburettors - and also the solenoid diaphragm fuel pump. The Minor used to stall towards the top of a steep hill going out of Oxford, which I eventually traced to fuel starvation. New contacts in the pump for £1.50 and a couple of hours fiddling solved the issue.
  14. That's interesting, because I've always felt one of Obama's biggest errors was to refer contemptuously to Putin's Russia as a "regional power". I remember wincing when he did that (probably because I'm in Europe rather than the USA). I suspect that remark was the original catalyst for Putin's revanchist drive, the fruits of which culminated in invading Ukraine. Unnecessarily pissing off psychopaths turns out to cause disproportionate trouble later on. No, that is just "bothsidesism" or false balance, giving undeserved respectability to an indefensible position. The USA offered no coherent rationale, and no evidence of any threat, to justify the attack. All we got a set of conflicting, changing and vague stories from the adminstration, ranging from regime change (justified how?) to securing nuclear material (how?), to the threat of probable retaliation against the US (how?) due to an attack Israel was in any case planning (why not instead dissuade Israel from doing that?). The evidence Trump is behaving irrationally comes from his own mouth. All you have to do is listen and you immediately see the inconsistencies from one day to the next, the vagueness, the capriciousness - and in fact the sadism, the most repulsive recent example of which was the relish with which he talked of "bombing our little hearts out". Trump would absolutely start a war for no reason if he thought he could have an excuse to hurt a lot of people. It would make him feel powerful. That's what turns him on. Trump has a rapist's mentality. And with Hegseth at the Pentagon, he has a kindred spirit.
  15. exchemist replied to DrmDoc's topic in The Lounge
    I think it may be more to do with droplet size. My understanding is that carburettors atomise the fuel into a fine mist rather than necessarily converting all it to vapour. But for sure the heavy ends have quite a low vapour pressure so won't evaporate quickly and may start to coat the sides of the inlet manifold, for instance. (It is noticeable how messy the ground can get at filling station fuel pumps that dispense diesel fuel. Any spills hang about instead of evaporating.)
  16. Yes and the thinking of those clever folks informed the 2015 agreement negotiated with Iran by Obama, the UN Security Council and the EU - which Trump tore up, preferring apparently to treat Iran as a caricature. Or else just because Obama was black. Very "rational", that.
  17. I'm sure this is right. My assessment of Khamenei's policy was to enrich to just short of bomb grade and stop there, so that Iran could plausibly say they had no bomb ambition, but to have in reserve the capability to get there very quickly if conditions were to change such as to require it. They probably foresaw exactly the kind of pre-emptive attack by the USA and Israel that has just taken place. That would make them wise planners, not "mad mullahs". The notion they would invite destruction of their country in a retaliatory strike by Israel, if they were to nuke Israel first is I think quite absurd. Though it is what Israel has hysterically been working on the Americans about for years. The whole notion of mad mullahs misjudges them entirely. There is no evidence the Iranian regime is irrational. Quite the contrary, as recent events have shown. Brutal at suppressing dissent, yes, of course. Irrational, no.
  18. exchemist replied to DrmDoc's topic in The Lounge
    Paraffinic heavy ends would resemble light luboil, so I’m not sure it would be that much of a problem. After all, diesel engines are built to a very similar design and don’t get gunged up. But there could be trouble with the carburettor, I’d have thought, with atomisation of the fuel.
  19. exchemist replied to DrmDoc's topic in The Lounge
    Indeed, in fact 7.5:1 according to Wiki, with the original 803cc version. : https://en.wikipedia.org/wiki/BMC_A-series_engine By the time my Minor was built it was 948cc and a compression ratio of 8.3:1, eventually raised further to 8.8:1 by the time of the 1275cc version in the go-faster Minis, in the 1970s. It seems that, after the revamp to the A+ the same basic engine continued until 2000, by which time the compression ratio was 10.1:1. Power output was originally 28hp and in the final version was up to 76hp. Quite an evolution. But I think one does tend to get this with IC engines. The 16SVT in the Class 40 diesel locomotive was rated at 2000hp, 2700 in the Class 50 (with intercooling) and in the much later Class 56, 3250hp. I've seen similar progressions with marine diesels. It seems because a new engine is such a big investment, the basic fixed components like the block are often generously designed to allow a lot of subsequent development.
  20. I had an awful feeling it might come to this. Let's hope the military professionals hold the line against insanity. I have a fair degree of faith in them. Especially since it is increasingly evident that the president is off his rocker.
  21. That's nonsense. There is no justification for this attack. Iran posed no immediate threat of any magnitude to the USA. No credible level of threat has even been asserted, much less corroborated. Furthermore no clear war aims have been articulated. Nor is this in any way a war of perception. It is a war with very practical consequences. These include civilian deaths in Iran including a school full of little girls, serious damage to Iranian infrastructure and civic buildings and to oil, gas and American military installations in the Gulf States. It is having a major effects on economies right across the world. As for "perception", the perception is that Trump has screwed up. Badly. Thanks to this ill-conceived operation, Iran has learnt what a powerful negotiating card they have in closing the Strait of Hormuz, something they had never before attempted. And they still have the military means to do that, because all they need is a few drones, which they have been mass-producing for years and which can be launched from almost anywhere in the country, which is vast. There is almost nobody outside the White House who thinks this is going well, or that any outcome will be better than could have been achieved by the negotiations that were broken off by the US when they decided to attack. And the cost of it all is huge.
  22. exchemist replied to DrmDoc's topic in The Lounge
    The A40 had the same A-series engine as the Minor. My Minor was 948cc though there was a 1098cc version and even, in some later Minis, a 1275cc version. But quite small engines and I suppose feasible to crank by hand. I think there was a free end of the crankshaft at the front to which a crank handle could be fitted, as your picture of the A40 shows. But I didn’t have a crank handle for it and would never have dared to try that. If the battery went flat one would get some mates to give it a push, just as my son now does with his Fiat Panda, or use jump leads.
  23. exchemist replied to DrmDoc's topic in The Lounge
    Ah yes, that’s it. So originally all the timing adjustment was manual, without any automatic centrifugal or inlet manifold compensation. So the driver tuned it by ear, presumably optimal just before the onset of pinking. And sure, if you did not fully retard the spark when cranking, the engine could fire backwards, in which direction the ratchet would not disengage, so the handle would whizz round, potentially breaking your arm. But I can’t help thinking there may have been an intermediate point, later on, when automatic compensation had come in but there was still a need to adjust for variations in octane number of the fuel.

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