John Cuthber

One would work if it was tall enough.

I don't think it is very volatile. It decomposes on heating and gives HF which is ... bad for you.

There are several options. Replace all the blanks with "one". Replace all the blanks with ">=1" Replace all the blanks with "unimportant". Replace all the blanks with "less than 99"

Doh. It's me failing to account for BC / AD.

Same way that they did it 1200 years earlier I guess... https://en.wikipedia.org/wiki/Eratosthenes#Earth's_circumference

Debating with a flat earther is probably a waste of time. However, if you are going to persist, ask them to email someone in each to the Earth's two hemispheres and take a picture of the moon and send it to them. One of the pictures will be the "wrong" way up. That can't happen unless they have different ideas of which way is "up" and that requires a non-flat Earth That's very simple, it doesn't need complicated kit and he gets to choose who the Southerner and Northerner are, so he can claim that someone is lying. Another is to ask them to explain the flight times between distant cities. For example, Greenland, India, South Africa and Egypt. That takes a bit more maths.

It's remarkable. We quite often get memes about Republicans doing really stupid things. When an elderly man who is a Democrat does something eminently sensible- wearing gloves in cold weather- the internet explodes.

Then 4 days ago the thread gainsaid this assertion:

Are children the only people who can't be relied on to give informed consent?

... and the UK https://covid19.nhs.uk/pdf/introducing-the-app.pdf ... where it works badly

Why not the children? Can't they decide for themselves? As you said

Yes, that's a simple idea. Now, who gets to choose on behalf of children? For example, who gets to choose if babies get vaccinated?

I'm not sure it's meaningful to talk of "curing" psychopaths. But could we please stop electing them to positions of power?

Is there a reason why neither of you said anything about absorbing neutrons (i.e. what the OP asked about)? Anyway, I think the answer is that slow neutrons are generally more likely to be absorbed into the nucleus. e.g https://en.wikipedia.org/wiki/Neutron_capture#/media/File:Neutroncrosssectionboron.png

And off he went with a Trumpety Trump; Trump, Trump Trump. For those unaware of the original... https://en.wikipedia.org/wiki/Nellie_the_Elephant

Recent... as in since the Civil War, or what?

Unless rafael returns and explains his wallpaper designs, the answer is no.

Soon to be followed by "I fought the law".

I see Trump has decided to pardon the swamp, rather than draining it.

Seems an odd experiment. Was the system sterile apart from the rat dropping?

So that's the sort of "free market" he believes in- one which hands money to rich people.

You can choose the "cold" temperature anywhere you like - even above 100C (though that's no longer a condensing boiler). The merit of a condensing boiler is that it recovers the latent heat from the water vapour produced by burning fuel. The amount of energy that is present depends on the amount of water vapour present, and the amount you reclaim depends on the amount of water you condense. The colder you get the outgoing air, the more heat you can recover because more of the water condenses. But, the law of diminishing returns sets in. By the time you have cooled the air down to 55C you have reduced the vapour pressure by about 85% compared to 100C. If you had a perfect mixture of methane and air you would end up with this 2CH4 + 4 O2 + 12 N2 --> 2CO2 + 4H2O +12 N2 (I have included the nitrogen in the air, even though it doesn't react.) The outgoing flue gas would be 4 /(2+4+12) =4/18 i.e. 2/9 water vapour by volume. (and very hot) That's 22.2% water vapour You could run that through a heat exchanger. If you were making steam you could run the heat exchanger at 100C (not very efficient but...) The flue gases would be at 100C At that temperature there's going to be no condensation (at 1 atmosphere pressure) Imagine you add a second heat exchanger to warm up the ingoing water. What happens when you cool the gas mixture. Well, initially not a lot. It just cools down. You can use the sensible heat (that's a technical term) to heat the water. But, when you get the temperature down to about 63C the water starts to condense out (that's the temperature where the vapour pressure is 22.2% of normal atmospheric pressure- there's a table here) https://en.wikipedia.org/wiki/Vapour_pressure_of_water As the gas gets cooler, more water condenses out. When you are down to 55C, you have reduced the water content to about 15.5% or so. And you have reclaimed (very roughly) 22.2-15.5 % of the latent heat. 7% or so. If you cooled it to 45C you would drop the outgoing water concentration to about 9.5% And that would let you recover more of the latent heat- 22.2-9.5 % i.e. about 12% OK, that's better than only recovering 7% of it, but there's a price or two to pay. First, you need a bigger heat exchanger. Secondly you need to run the system with a cooler return. But running a hot water system with colder water is a potential problem. So there's a cut-off where it's not considered worthwhile. That's an economy decision and, at the moment, the compromise between heat recovery and size (and cost) of the exchanger and the difficulty of getting a hot water system to cool the return water is about 55C With bigger, cooler, radiators in the house, you could do better. But that would also be expensive. So there's nothing fundamentally magical about 55C. It's a compromise. (Incidentally, I have ignored the heat that goes into or comes from the air, and also the fact that it expands when hot. I'm lazy and the maths is not helpful here.) We are talking about the temperature of the cool water return to the boiler. It's the hot water from the boiler that scalds people.

Can you clarify? Is he unwilling to pay because he's a selfish bastard who wants to keep the money, or is he unable to pay because his business is not viable and only runs because the guy on $10 per hour also gets handouts (of my tax dollars) from the state? How did you get there? Were you voted in by people who recognise that the talk about cottages is a straw man?

There's no guarantee that it's half, but it must be some. If it was less than half, that would imply a really bad design, but if the proposal is that phones are bad for you, a really bad design is one of the initial assumptions.

No radio transmitter is better than 50% efficient. (The rest is wasted as heat) No battery is perfectly efficient. (Some energy is lost as heat) Some of the RF signal escapes to make contact with other phones. (and so it can't be dissipated in the skin as heat.) So it's clear that most of the heating can not possibly come from the radiation. Incidentally, if I had a pair of gloves that reliably kept my fingers 5 degrees above ambient, I'd be quite pleased.