exchemist

Not sure. In practice it looks as if synthesis of HFCs was not not done by "burning" hydrocarbons in fluorine gas, which probably just gives you an unholy mess, but by a more more controlled reaction, involving ionic displacement of Cl by F, or addition of HF across C=C double bonds, and processes like that.

Yes, somewhat: C-H ~ 400kJ/mol vs. C-F ~ 480kJ/mol. For comparison C-C and C-O are ~ 350kJ/mol. Diatomic fluorine gas is certainly highly reactive and tends to displace hydrogen from organic compounds (in fact often "burning", complete with flame, as if it were oxygen!) , but this is largely due to the anomalously low bond energy of the F-F bond, which is thus easy to break. This low bond energy is attributed to the small size of the atom: high nuclear charge for a given valence shell (n= 2) as one gets towards the right of the 1st short period, so forming the bond to complete the valence shell introduces a lot of electron-electron repulsion - more so than for larger atoms. So I think it's more the instability of fluorine gas than the stability of the compounds it forms. A range of perfectly stable compounds with mixed C-H and C-F bonds is available (HFCs were one of the greenhouse gas bad actors in former refrigerants), so the disparity in bond energy does not prevent F playing a fairly well-behaved role in organic chemistry.

Yes, like @joigus and @swansont I don't follow this. Fluorocarbons don't require any less carbon than hydrocarbons, for a given chain length. The virtue of carbon, surely, is its unique propensity for catenation, viz. forming long chains, linked by covalent bonds. Your proposal does nothing to lessen dependence on this so far as I can see. Fluorine forms only a single bond, so can't substitute for carbon in this role. By looking at fluorocarbons all you are doing is substituting F for H. As H is the most abundant element in the universe, that would seem, on the face of it, an exercise of doubtful value. Graph of relative elemental abundances below: From: https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements You also need to pay some attention to what solvent a life chemistry will use. Water would be fairly useless with fluorocarbons, I suspect. Are you envisaging HF or something as the solvent?

Or perhaps the poster meant not volume but bust measurement. That would presumably be a bit less without support.

Why would whether they are in a bra or not affect volume? I would expect the volume to be the same, but just the shape to be different.

I explained in my previous reply why this does not work as you seem to think it does. You seem to have ignored this. The answer to your question is that policy makers do not share your silly ideas.

So far as I can discover, this Dean bloke seems to be some sort of self-promoting (and quite likely self-publishing) nutcase. I can’t find evidence that anyone takes him seriously. What you have posted about his arguments does little to alter my impression. Are you Dean?

Suggest you first consult a dictionary and then come back with any specific points of clarification that you may have.

Main engine will be RFO for sure. It’s a big one: 9 cylinders of 90cm bore. (The C will I think stand for container ship, normally meaning higher rpm and shorter stroke than, say, the variant for tankers.) However I have just remembered it used to be the practice in some areas to switch to MDF in coastal movements, to comply with local emissions regulations. So what you posted about MDF could be relevant.

Your link is about MDF. I wonder if the ship was burning that or RFO. (My comments about centrifugal separators relate to RFO.) I heard an interview with a bridge designers saying that if and when they rebuild it, it will probably be a cable stay bridge with piers set much wider apart, well out of the navigable channel.

What puzzles me is the loss of all power. There will have been a low speed main engine and a number of medium speed auxiliary generators. While they may all have used the same heavy fuel oil, it seems odd that all would have failed simultaneously due to fuel contamination, especially given there will have been several centrifugal separators on the fuel lines to the engines. Low speed engines are generally more tolerant to poor fuel than medium speed ones. Maybe loss of electrical power meant they could not control the main engine or the rudder. No doubt the facts will emerge fairly quickly though.

As always, context is critical to the understanding of quotations. Lavoisier was talking of matter not being created or destroyed, in the course of chemical change. You seem to be trying to apply this saying inappropriately, to heat, which is not matter, but a form of energy. Energy is a property of physical systems that is also conserved, i.e. neither created nor destroyed, though this principle was unknown in Lavoisier's time. However energy can and does change from one form to another in the course of physical processes. In the case of the growth of trees, there is chemical potential energy (which is not heat) stored in the molecules that make them up. That chemical energy does not come from heat but from the energy of sunlight, which is captured by the tree in photosynthesis. The Earth is not a closed system, where energy is concerned. It receives energy from sunlight all the time and radiates heat off into space. These two should be in balance. Climate change results when the rate of radiation into space is reduced a bit, due to the atmosphere slowing down the rate of escape of heat. It is caused by the absorption of infra red radiation (heat radiation) by gases and vapours such as water, carbon dioxide and methane.

This is offensive, rambling nonsense.

Yes I think one of my son's friends at school, who was autistic, went on do an arts subject at university. And we have the example of Greta Thunberg of course.

OK, well in that case what I posted shows it cannot be a widespread effect, at least. But I suppose it does not rule it out as an effect in certain individuals.

I may have misunderstood then. What exactly is the hypothesis that has not been refuted?

So Adlock as opposed to AdBlock? How very confusing.

I would not have guessed, Markus. Except that you are rather good with hard mathematical physics…..🙂

Yet clearly it has little long term effect in practice, since amoxicillin is widely prescribed (in the US, as much as 24% of all antibiotic prescriptions:https://www.definitivehc.com/resources/healthcare-insights/most-prescribed-antibiotics) and we do not see any mass outbreak of sterility in the population.

Thanks. I looked at that but it was not clear to me it can work with Apple Mac OS and Safari.

My son knows several people, formerly at school and now at university, who are on the autistic spectrum and obviously highly capable. The fact - which I had absolutely no idea about - that @Markus Hanke is also on the spectrum (!) is another illustration. I have my suspicions that various eminent figures in history (Newton, perhaps?) may also have been. People of my son's generation are getting quite comfortable with the idea that autistic people can fit into society perfectly well. But then there are other cases that are clearly very difficult. At the other end of the scale, when my son was small one of his schoolfriends was a little girl who had an autistic brother, who still could not speak at the age of 5. (This girl once told him that when she grew up and married him (!) she wanted 3 children: one boy, one girl and one autistic. )

I have now experimented with AdBlock Plus, which is free on the App Store, for my iPad. At first it did not do much, but a few days ago I found the app contains an option to permit what it calls non-intrusive ads, which is by default enabled on the grounds that the AdBlock people recognise websites need to make some money. My experience however is that that still permits most of the annoying, moving ads that are so distracting to the reader, e.g. on newspaper websites, to get through. I have now found that by turning that off I can suppress these and my reading experience is now vastly improved. I have the feeling it may also stop the ads coming up in the middle of YouTube videos, though it still allows the ones at the start. I'll give it a few more weeks and if no snags emerge I'll install it on the laptop as well.

This seems written from the point of view of the company (Honeywell), that was and maybe still is trying to promote this apparently expensive and and hard to install system. As I read it, it would only work at 35 airports and would need to be customised for each one. So hardly surprising the authorities did not jump at the chance. If you read on in the piece, there seem to be less costly alternatives in development.

You've left out the ironing.........

I got off my hamster wheel some time ago. I don't understand the rest of your post at all.