exchemist

Yes, I did the same about 20 years ago, since I need to be able to write with my right hand while using the computer. You don’t need much dexterity to operate a mouse.

This article explains almost nothing, so it's impossible to say. It looks like a gimmick to me. What's the point, especially since the light has to be supplemented with electricity?

The difference is the way they get their energy input to work against entropy, basically. Desalination plants often use reverse osmosis, in which pressure is used to force water molecules through a semipermeable membrane that does not allow the larger, solvated, salt ions through. (Although an individual Na+ or Cl- ion is smaller than an H-O-H molecule, these ions in solution are surrounded by a solvent "cage" which is quite tightly bound to it and makes their effective size a lot bigger.) Alternatively distillation is used, often under reduced pressure to permit boiling at a relatively low temperature. (Boiling greatly increases the surface area for evaporation, accelerating the process, due to the surface area of the bubbles). The very large desalination plant at Jebel Ali, in the UAE, used that method, I remember, from when I lived in Dubai in the 1980s. It employed waste heat from the Jebel Ali steam power station - quite clever. A solar still relies on heat from the sun, rather than an artificial energy input. So the energy input is in a sense "free" - and non-polluting, of course - but you are limited to the energy density of sunlight. Solar stills also have to rely on evaporation at atmospheric pressure, which further constrains their capacity.

Mine is how to preserve wine in good condition after opening a bottle, if you don't have enough people to finish it. I bought some screw cap half and quarter bottles of wine at the supermarket and kept the empties. Now, when I open a bottle, I decant half into an empty half bottle, making sure to fill it almost to the top so there is negligible oxygen to oxidise the wine, screw the cap on tight enough for an airtight seal and keep it in the fridge to slow down any reactions that may take place. If I'm on my own and only having a quarter bottle with my meal, I put the 3rd quarter into one of the quarter bottles on the same principle. I have found it is certainly possible to keep both red and white wine for a week this way, without noticeable deterioration - and even 2 weeks at a push, though it does tend to get a bit thin. This method is infinitely superior to those pumps and stoppers you can get e.g."vac-u-vin", which in my experience barely work at all. I resorted to this due to my tendency to atrial fibrillation, which can be brought on by alcohol. It has enabled me to continue to enjoy modest amounts of wine without getting into medical problems. ( I have just had an ablation, which I am hoping may get rid of the AF, but I need to let my heart settle down for a couple of months and learn the new conduction pathways before putting it to the test.)

On forums, watch out in particular for bogus posts made to promote journals from the SCIRP family. SCIRP does this a lot. Perhaps you have noticed the same thing. Posts made by new members, on the subject of journal reliability, are always worth treating with a degree of circumspection.

What were you going to calculate, based on valence electrons?

Splendid, splendid.

Do you want to discuss chemistry or computer programming?

OK, I'm delighted you have replied. We get a lot of bots and drive-by spammers and I thought you might be one of those. I do think there's a problem with multiple oxidation states. Higher oxidation states of, for example, transition elements, tend to form bonds that have a lot more covalent character than lower oxidation states of the same element. This is not surprising when one thinks of the ionisation energies or, which comes to the same thing, the polarising power of a highly charged cation. I also wonder if you might give a better overall sense of what is going on if you were to use a colour coding scheme to distinguish the types of bond, instead of writing out the text each time. After all, you only mention 2 or 3 types of bonding. But good luck with your project.

Oh I see. Good idea, then. Although in my view the table would still be of highly doubtful utility.

Thanks. But making your readers go to that trouble doesn't seem a great way to make the table someone's first choice as a reference.

Quite so. I've often had cause to remark on how many Tory politicians seem either to be aliens, who make you want to exclaim "Christ! They've landed!": Or people who you expect to see being pursued down the street by men in white coats: I could post more images, but perhaps not appropriate for a Sunday morning............

I don't find this table useful, to be honest. You can't see the row and columns headings once you are in the middle of it. It also makes simplistic - and therefore incorrect - generalisations for those elements that can occupy a variety of oxidation states, for example the transition elements. I really don't see the point of such a table. Far better to look at the Periodic Table and consider electronegativities and oxidation state for each case.

I assume the objective must be to precipitate MgCO3. Mg(HCO3)2 does not exist as a solid (presume the Mg ++ cation is too small for 2 big HCO3- anions) so it won't precipitate as bicarbonate. Or alternatively just to convert dissolved CO2 to HCO3- in solution. But it seems at first glance a bit daft. Where would anyone get huge enough quantities of Mg(OH)2 from, in order to make an impact on the vast amount of CO2 dissolved in seawater? I've found the publicity blurb from the company in question: https://www.planetarytech.com/projects/cornwall/. It looks as if it is just a small scale exercise to confirm some models. There is no explanation of where they would get enough minerals to make a real change to the oceanic CO2 level, or what the effect might be of jacking up dissolved bicarbonate and metal cation concentrations. I do not believe it would be biologically neutral.

None of the 10 commandments says anything like that. There is one forbidding adultery, and another saying thou shalt not covet thy neighbour's wife. It was a very patriarchal society and tended to be written very much from a man's perspective. The decalogue is written out in the table at the foot of this article: https://en.wikipedia.org/wiki/Ten_Commandments

No I didn't mean anything to do with harassment. I just meant a normal, civilised, - if unwelcome in this instance - sexual approach.

They rely on metals being electrically conductive. An AC electromagnet induces eddy currents in the metal object, which alter the net field (from the detector and the metal) close to the object.

Possibly. Here is a link to the original PNAS article: https://www.pnas.org/doi/full/10.1073/pnas.2217090120 The "Interpretations" section is the most interesting. This runs through the various compositional ratios of Fe, S, O, C and H that they considered, in trying to match the observed seismic data. Interestingly - and rather counterintuitively to me - they alight on H as needing to be present to avoid having what they consider an unreasonably large proportion of S in the mix. This could fit your idea of cooler conditions and a faster congealing, compared to the Earth. But they don't themselves speculate on formation processes for the core. This work seems to be offered as food for thought, for other planetary physicists and chemists to study.

Interesting article. Thanks for posting it. One would not expect nitrogen-containing compounds among the minerals. About the only example on Earth is saltpetre (KNO3 or NaNO3), which is derived from decomposition of organic material. This is because nitrogen is generally speaking most stable as N2, a gas, due to the great strength of the triple bond (excellent overlap of the 2p orbitals in this small molecule, leading to 2 very strong π-bonds as well as a strong σ-bond). So one would tend to find nitrogen in the atmosphere rather than in solid minerals. (This is in contrast with oxygen, which of course happily forms a huge series of silicate minerals, oxides, etc.) All the elements up to and beyond iron will have been present in the dust and gas from which the solar system condensed so, rather than formation, this issue is more about fractionation, i.e. which ones became concentrated in particular planets, and then in what part of the planet (atmosphere, crust, mantle core). Sulphur forms a range of compounds with iron, some of which are not of fixed composition, i.e. solid solutions or alloys. From the article it seems they think sulphur is a major ingredient in the Martian core due to the composition of iron meteorites and also, I presume, their assessment of the density of the core from seismology.

Nice idea but there’s no way to get this to work, unfortunately. The USA has to join the rest of the civilised world and get rid of the permissive gun culture, however hard and slow that is.

None. There is nothing you can apply externally that will do that.

The cream of the joke is Carlson was fired for objecting to Fox’s campaign of lies. But it couldn’t happen a nicer chap.🤣

Once you break the rules of physics you are in a fantasy world in which all bets are off.

@swansont is quite right of course: I wasn’t thinking. We need more information. What is the shape of the mirrors, what is the shape and dimensions of the 600sq m illuminated area and what is the angle of the beam to the ground? Is a diagram available?

I'm not quite sure what you want to know. Do you mean a formula for the rate of divergence of the beam? That's obvious, surely, if it grows from 51m² to 600m² , i.e. a factor of 11.6, over the course of 450m? Or do you want to know why it diverges at that rate? That would be more complicated - some function of the shape of the mirrors, I imagine.