exchemist

The brightness of the cloud obscuring the sun will be generally greater than that of the sky or blue-coloured objects, so most of the light falling on the paper will still be white, even if there is a cloud preventing direct sunlight from reaching it. Consider: you can gaze at a blue sky far from the sun without discomfort, whereas looking at a cloud in front of the sun often involves screwing up your eyes. I suppose that, if the cloud were very dark (which it would never actually be in an otherwise blue sky, but never mind) then most of the light reaching the paper would be blue and it would consequently appear blueish.

Our local dump ( in London) has a separate section for electrical items. But I don’t know where they send it.

Can you summarise this error?

Yes, that article mentions that an overpotential is needed, which increases the degree of ionisation from its equilibrium value, thus speeding up the electrolysis.

On the contrary, I think we should be looking at both approaches. They should not be seen as mutually exclusive alternatives. It seems to me we need all the help we can get, from any method that proves viable. Since the transition from fossil fuel will take at least a couple of decades to complete, we ought to pay some attention to what happens to the CO2 that the legacy uses will be producing over that time. But this particular idea is not intended for that and would almost certainly not be suitable.

Yeah, it’s not for making a breathable atmosphere though, it’s as oxidiser for rocket fuel for the return journey. But in any case you can capture the oxygen separately at the anode and release the CO to the Martian atmosphere at the cathode.

This is rather clever. It relies on certain metal oxides acting as conductors for oxide (O²⁻) ions in the solid state at high temperature. At 800C, CO2 is reduced at a porous, nickel-based cathode, to CO and O²⁻, the ions travelling, by means of ion vacancies in doped zirconium oxide, to the anode, where they give up 2 electrons and combine into O2. Details here: https://en.wikipedia.org/wiki/Mars_Oxygen_ISRU_Experiment Neat, but indeed requires electrical energy to accomplish and generates carbon monoxide. As @John Cuthber points out, that would have to be disproportionated into C and CO2 in a further step, before it could be applied terrestrially. There are probably easier ways to convert CO2 to solids here on Earth, most of them biological and making use of sunlight rather than electricity.

Because those are the common forms of radiation emitted in radioactive decay. So they were the first to be given names, before it was even known that only gamma rays are actually EM radiation, the others being particles.

Well actually I think that’s a bit of a non-story. All it says is we don’t have recycling capacity yet. But that’s to be expected, since the panels installed over the last decade won’t need replacing for another 15 years. Nobody is going to invest in a plant that will sit idle for years.

I can’t see offhand why someone couldn’t make an engine with such a cycle for demonstration purposes, though like you I can’t find any examples of it having been done. It does seem, though, that such an engine would probably work rather slowly and so might not be a very practical source of mechanical work. One would need insulating shutters to alternately expose and shut off the working fluid from hot and cold sinks (assuming a cylinder whose walls had negligible heat capacity) and then let pseudo-adiabatic expansion and compression occur in between. Or something. You’d have thought some enterprising soul at Imperial College or MIT - or perhaps at one of the Grandes Ecoles in Paris - might have given it a go.

I didn't watch it all. The guy's accent is so strong it's a real challenge to understand him. What do you think he is proposing, then? A rule of thumb is it's the amps that kill you not the volts. A battery sounds dangerous to me as it can store a lot of charge, i.e. can supply a lot of amps in a short space of time. A van der Graaf generator on the other hand supplies a high voltage but only stores a tiny amount of charge.

At the risk of being thought racist, I would NOT trust a video from the Indian subcontinent showing somebody putting a screwdriver into an electric socket. When I was in Dubai we were constantly stopping people from that part of the world from doing dangerous things with electricity. Their safety culture around it seemed non-existent. You can safely send sparks between people if you have a van de Graaf generator, but don’t even think of doing anything involving mains electricity.

Many Englishmen get through a litre or more of tea each day, of course. But not in one go.

And in fact at that temperature it makes bugger all difference whether you use C or K.

What you calculate is the integral. Have you looked at the example I gave you a link for? That shows you how you do the calculation.

I find the graphical representation of this the most helpful in understanding it. If you plot f(x) against x as a curve, f(x)dx - i.e. f(x) times the infinitesimal length dx along the x axis - is an infinitesimally thin vertical strip of area under the curve at the value x. If you add up a series of such strips you get a block of area under the curve. That is what integration does: it gives you the area under the curve representing the function, between two points on the x axis. The integral sign, ∫ , indicates a sum of these infinitely thin strips, adding up to a finite value for the area. Here is one example: https://www.bbc.co.uk/bitesize/guides/zq3ggk7/revision/1 This basic idea spins off into a host of applications, all over natural science and engineering.

Wouldn’t such a drive mean the laws of physics can change with time, though? In which case Noether’s theorem would not apply any more.

No it isn't. N14 can react with a neutron to generate C14 plus a proton. That is how C14 is generated in the atmosphere from the effect of cosmic rays. So your bomb is going to convert nitrogen into carbon, which will probably eventually form CO2 with some of the oxygen in the air. So it seems to me that - aside from all the other issues with this preposterous idea - your bomb is going to increase the CO2 in the atmosphere rather than decrease it.

Evidently not, at least if their freedom of motion is suitably damped. But it seems a lot depends on the speed of rotation, i.e. the vibration frequency: at some speeds it indeed makes things worse but the idea seems to be that at design speed of operation it tends to cancel the out of balance forces. It is evidently highly mathematical and it looks to me as if one would need to be a rotating machinery engineering specialist to understand and explain it. For instance, look at this paper: https://asat.journals.ekb.eg/article_22757_440eb67a81fd7bbd66129baee93f72cb.pdf I'm afraid I don't have the background to be able to follow this. The principle seems to have been discovered by a chap called Thearle in 1932. Perhaps if you look him up you may be able to find a simpler explanation of it.

In the course of this thread we have I think established that a neutron flux will not convert C12 to C14 to any significant extent. But it will indeed be produced from 14N and apparently 17O. So what one would get is a net increase in the carbon dioxide in the atmosphere, created from N and O. Brilliant, eh?

That's because French dinners are social occasions. They don't eat that much, generally. In fact, one benefit of that style is that there is plenty of time for one's system to react and send a signal when you have had enough. (My late wife was French, so I have some experience of family gatherings.) I understand that one factor in obesity can be the bad habit of wolfing down food very quickly, as it takes time for the body to react to the amount of food consumed and send a "full" signal. So if one eats fast, one runs the risk of overeating. A slow succession of small courses, in which ones chooses how much of each to take, is far better from that point of view. I doubt that anyone in France (apart, perhaps from Obelix, who is no role model) would drink a whole litre of milk in a few minutes. It would be thought rather barbarous, I suspect. The French are a lot slimmer than the Americans - or the British.

I did not know what these were until I read your post but, having looked at a few references, e.g. this one: https://www.sciencedirect.com/science/article/abs/pii/S0094114X15001937. my understanding is the balls move so as to take up positions at which their mass tends to bring the axis of the total moment of inertia closer to the axis of rotation. They thus don't just damp the out of balance forces, but actually reduce them by shifting the CoG. Secondly, by doing this they reduce the lateral accelerations (i.e. vibration normal to the axis of rotation), not changes in angular velocity. At least, that would be my reading of how they work.

I don't know but I imagine it is that such an engine might be rather impractical for doing useful amounts of work. A Stirling cycle has pseudo-isothermal heat addition and removal, but then there's the thermodynamically complex issue of the heat regenerator.

OK but that would just heat the air up, surely?

Except it would not, as has been explained to you. Very little, if any C14 would be produced and the subsequent decay into N14 would take thousands of years. "Kinetically charged" is meaningless, by the way. What do you mean by kinetic charge, and what is it that you think would be "kinetically charged"?