How is the public key published? Even more important, how do you revoke a key? All the public key allows is verifying that the message came from someone with the matching private key- not you.

I'm sure some of the airframes will be converted to cargo- when they say "retire" they don't mean "immediately crush for scrap" - they sell them off. Their 747-400s were all in storage anyway.

TFA doesn't mention the costs- but the Science article does go into the calculations quite extensively. If you don't want to sign up for Science- I suspect you can get the article via sci-hub.

The Nature article references this, in terms of reduced efficacy. It also mentions that the reason why limestone is used is that intensive farming leads to the acidification of the soil. As to the cost of the techniques- they are also discussed in the environmental economics model. If you don't have access to Nature, I suspect you can get to the article via sci-hub.

This seemed a pretty wild claim, so I decided to look at the current but the current (amended) act has no such provision- It mentions stopping granite research, but does not prohibit it:

Your numbers kinda confirm what I said- at 1 ton per bore and 200-300' per bore, that is, roughly 700' to 1000' of overall bore. Homeadvisor says the current cost of drilling a well in Texas is $30-$55 per foot, and that is only the cost of the actual drilling. So, on the low end, $21,500, up to $55,000- for drilling through rock- I expect the higher numbers. And remember, this is a SWAG for a modest (by today's standard) home of 2000 sq ft, (3.5 ton HVAC). A super efficient home can potentially use less, but normal builds around here are much larger.

I looked into ground source heat pumps a couple years ago. I really wanted to do it, for the efficiency and just to avoid having the sound of the outside unit of the heat pump- it just doesn't make sense in this climate zone, with this ground.

Going back to my original assertion- there is no single solution that is best. The best solution will always be tailored to the conditions.

There isn't a good "one size fits all" solution. Where I live (Central Texas) summers are very hot, with quite mild. Heating is infrequently used. Ground source heat pumps are very expensive because of the combination of soil type and typical heat differentials. Pretty much, there is no soil, so a ground source heat pump needs to be drilled into the limestone (very expensive), the ground near the surface is pretty warm, so you need more wells (or deeper wells) in your loop. For a SWAG- a 2000 sq. ft home in this region needs about a 3.5 ton system, ground source needs on the order of 300ft/ton, or about 1000' of well. Through rock, the cost is on the order of $50/ft- so you can be approaching $50,000 just to drill the well! The well (or at least the pipes) don't have an infinite lifetime, either.

48V is a pretty common Telco supply- there are lots of very efficient converters that work at this level, though they tend to be extremely pricey, but volume could bring the cost of them down. There is a niche for server power supplies (which already use the 12V standard, 3.3V STBY excepted) that convert 48VDC to 12VDC, and are a simple swap from the supplies that convert AC line voltage to 12VDC.

12V is chosen over higher voltages at least in part by UL and other safety type agencies/organizations. 20V seems to be the magic number- over 20V and you need to have things much more protected from fingers being able to touch an operating circuit. 20V is somewhat arbitrary, but in my own experience, in the range of when my reasonably dry fingers start to feel a tingle if I touch a live circuit, but still below the amount of current that can cause harm (most, but not all circumstances).

I work with a couple major server manufacturers, and 12V supplies have been the norm. briefly skimming the article and previous comments I did not notice the point that the big current users on most really high performance chips are really low voltage- 1.5V or below, and due to the simple aspect of resistive losses, are already subregulated very close to the consumer. We get the really low voltage because of transistor density- the more we pack onto a single piece of silicon, the smaller transistors get, and a small transistor can only withstand a lower voltage.

2009, actually. Campy. My favorite memory of this movie is that I watched it on Netflix- and my ex, a high school teacher, also used the account for showing movies (relevant movies- she was an English & Theater educator), and "Bitch Slap" would show up on the opening screen!

"The Three Burials of Melquiades Estrada" is outside of what many others are posting about, but just an amazing film. Probably mentioned in the 2003, but "Infinity" is an interesting view of Richard Feynman.

Assuming it is a Li-ion battery- 3.6V nominal and 4Ah there was 14 Wh stored in the battery. The charger used about 80W over the time 17/60th of an hour- about 23 Wh provided- so 9Wh ends up as heat, using a conversion- that means about 32000 J.

To put this in perspective- 12oz of water is about 340g, and the specific heat of water is 4200 Joules per kilogram per degree Celsius (J/kgC) so... 32000 J /(.340 kg * 4200 J/kgC) = 22C (72F) - not an insignificant amount of heat. Not crazy though.