exchemist
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Everything posted by exchemist
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No. Move to Europe, where these silly antiquated measures are not used.😁 More seriously, I went to school in the UK during the transition to metric units and had to learn both at school. If you live in a benighted country with these ancient systems, you just have to learn them, I'm afraid. P.S. I never knew a "cup" was an actual measure. We had to learn gills, quarts and gallons. It seems there are 2 gills in a cup. So I've learnt something today.
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Yes I agree. However it is normal in most western countries for illustrations in children's books to show a mixture of sexes and ethnicities, simply to make sure all the children see the book, and the subject, as being "for them". Especially perhaps with maths, as this has some baggage of -ve stereotyping, viz. a history of being seen as "nerdy", or "for boys" and so forth. So if that's all it is, then it's disgraceful that books are withdrawn for it.
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The integral, with respect to t, of 1/t is: ln t +C, surely?
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A winglet is to reduce wasted energy from wingtip vortices. That is a different thing.
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No reply yet from the person I was hoping might respond, but someone else reckons they are vortex generators to improve the air flow towards the wing tip, where, due to the flexing of the wing, it is (so I'm being told) the part likely to stall first as the angle of attack increases.
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Yes. The problem is fracking may be sold by our idiotic government as short term, but it isn't at all. The best short term options are renewables. Regarding education, that's a different topic but I've just listened to an episode on "The Briefing Room" on Radio 4 about Britain's poor economic productivity, which (among other things) laments our rigid education system. This fails to turn out the sort of mid-skilled people one needs to provide the bulk of the workforce in a higher productivity economy, like that of Germany or France. Our record is very poor compared to theirs. We are fixated on A levels, which are extraordinarily narrow (my son chose the IB instead), and on going to university to study more narrow disciplines, often of questionable value. Different governments try different gimmicks, like the apprenticeship scheme, but there is no consistency and so it never takes root and starts to show results.
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If they want more energy, cheaply and fast, they ought to be erecting wind turbines and encouraging farmers to put solar panels in the fields instead of trying to ban the practice. That could make a difference within 18 months, if they can bypass the planning process for an energy emergency. But they are far right fuckwits, unfortunately. (Rees-Mogg as Energy Minister? Seriously?) My understanding is that some abandoned N Sea fields - which would be economic once more at today's stratospheric prices - could be restarted a lot faster than 5 years, but I don't have chapter and verse, I'm afraid.
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I don't think explosives are used, are they? My understanding is it is done via hydraulic pressure. An article in yesterday's Guardian, from a former geologist for Cuadrilla, expressed the view that rocks in the UK are too heavily faulted for there to be many contiguous reserves, big enough to be economically recoverable. The current boss of Cuadrilla, interviewed today on R4, seemed more sanguine. However his estimate of recoverable reserves seemed to be 10x that of the British Geological Survey. I can't find numbers on this, unfortunately. But it seems there is no consensus on the size of the prize. What I have found is papers on the BGS report on induced seismicity: https://www.gov.uk/government/publications/review-of-the-geological-science-of-shale-gas-fracturing The other things to bear in mind, apart from induced seismicity, are the long lead time before gas from these new sources can enter the market (>5 years, typically) and the fact that when they do so, they will be priced at the global market price, so they will not make supplies any cheaper, though they can add to security of supply.
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I found this immediately on a web search: https://www.metric-conversions.org/weight-conversion.htm There must be lots of them.
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And I thought that was "Budweiser", the one made partly from rice. Real Budweiser, from Budweis,(Budweiser Budvar) is actually not bad, however. For a lager.
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Looking for basic theory on mixing of gases
exchemist replied to random_soldier1337's topic in Engineering
You can also get "static mixers" to put in the pipe, to speed up the mixing and ensure it is complete: https://komax.com/the-gas-static-mixer-produce-high-quality-process-gases-for-many-application/ -
I'm going to ask on another forum where there is an engineer who I think may have done some flying.
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I'm sure you are not dreaming! Since the beacon is often a rotating light, like a lighthouse beam, I imagine it would be expected to illuminate each one in sequence, though very rapidly. But we probably need comment from a pilot.
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Ah, I see. I wonder if it is significant that these are immediately ahead of the aileron. I think I've seen such things on other aircraft and always assumed they were not lights but small protuberances to aid airflow over the aileron. I could imagine that, if that is what they are, it's possible that at night they reflect light from a beacon on the fuselage. But I'm just speculating. I don't know if we have a pilot on the forum who can comment. Did these things seem to flash in unison or independently?
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By the way, didn't Geoffrey Wilkinson get his Nobel Prize for his work on organometallics, including ferrocene? If so, who better to know the unconventional (formal) oxidation states that can be involved?
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OK fair enough then: I don't know. But I guarantee it was not an Fe VIII compound. Maybe @John Cuthber will have a comment. He seems to be the best on inorganic chemistry that we have on this forum. I was hoping this discussion might bring him out of the woodwork, but anyway this will now ping him whenever he next logs in.
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Are you sure the aircraft was in clear air at the time? I've sometimes seen something similar when flying through very light cloud, which scatters light from the beacon lights on the underside so that a flashing glow becomes visible. Also could be something to do with the leading edge slat, or slot, that some aircraft extend for the approach and landing. I find it hard to think a diffuse beacon light would be helpful as a safety aid: you'd want something clear and bright, that could be seen for miles.
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Did you have any evidence that you made an Fe compound with an oxidation state of VIII? Or was it just a mystery reaction product that was not analysed? As far as Mellor is concerned, if he died in 1938 it seems likely that understanding of transition metal atoms and their chemistry when he was writing was less complete than today. The physics of QM only got going in the 1920s, after all, let alone its application to chemistry, and many of today's spectroscopic and other analytical techniques did not exist. I was at university about the same time as you and my Cotton & Wilkinson from that era says that for oxidation states of iron higher than III, "only for the states IV and VI are there substantiated reports of compounds." They go on to describe the tetrahedral, paramagnetic, ferrate ion.....
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What is the correct way to use a science based forum ?
exchemist replied to Ned's topic in Suggestions, Comments and Support
If you talk nonsensical crap, you must expect to get closed down. You have been banned over and over agin, from so many forums, that this message must have sunk in by now. The only explanation for you continuing as you do must be either that you have some insane compulsion to talk crap or that you are doing it for fun, as a wind-up. I incline to the latter view, as you know. -
But on this forum you need to express yourself in words, unfortunately, or at any rate without sending us off-site to click on on links of unknown provenance. It's been ages since we had a perpetual motion machine, so if you an explain it without sending us off-site to a link, it would be fun to identify the flaw.
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I'm afraid I am not au fait with what may have been tried recently in this area but I'd have thought there are reasons to expect Fe VIII not to exist, chiefly the effect of increasing nuclear charge as one goes across the period which will lower the energy of the valence shell orbitals, raising the ionisation energy and pulling them in, making them less available for covalent bonding as well. How recent is the work you cite that suggests Fe VIII ? I imagine Ru VIII and Os VIII might be expected to be similar to one another (due the effect of the lanthanide contraction on Os), and both of them to form high oxidation states more readily than Fe, due to having more diffuse (less strongly bound) valence orbitals. But I can't claim any practical knowledge of this. Maybe someone else here can.
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No, you need to take a more nuanced approach to this. Nobody is saying the 3-4 alkene is "not stable". It's more subtle than that. What we've been saying, and what the Zaitsev (or Saytzeff) Rule is saying [suggest you look it up], is that these elimination reactions, where there is more than one possible product, tend to favour the option with the more highly alkyl-substituted double bond. You will in general get a mixture of products containing both options, but there will be a higher yield of the one with the methyl substituted double bond. The reason is that alkyl groups are slightly electron-donating. You may be aware that alkyl groups are ortho/para directing in aromatic substitutions for instance. (F, by contrast, will be somewhat electron withdrawing.) More highly alkyl-substituted alkenes have greater stability (stronger bonds) than unsubstituted ones, as a result. How this occurs is a bit complicated, involving something called hyperconjugation, which gets into MO theory: you may or may not be covering this kind of thing in your course. But the question of "stability" is also worth thinking through a bit further, from the point of view of kinetics vs. thermodynamics. Both products are, so far as I can see, thermodynamically stable, albeit the Me-substituted one is of somewhat lower energy - the more stable of the two. So that answers the direct question you asked. But which product is favoured in the course of a synthesis reaction can be a question of kinetics as well as thermodynamics. The explanation of the Zaitsev or Saytzeff rule given in my old synthesis textbook is that the electron-donating (hyperconjugation) character of the alkyl group stabilises the transition state, thus lowering the activation energy and causing that product to form faster than the other one. This may be something to argue out with your prof.