phenol

thank you for actually reading the article and realizing that the team of energy scientists + engineers doing this have thought more carefully about the viability of the process than a HN commenter that learned about it this morning

kind of. the real figure of merit here is the levelized cost of hydrogen (LCOH), which requires you to build a technoeconomic model to simulate the total cost and production of a hypothetical unit over its lifetime. focusing just on "energy efficiency" will be misleading (in favor of geoH2!) because, relative to a green H2 elyzer, this approach has relatively lower operational costs (OPEX) and relatively higher capital costs (CAPEX) because you don't need stoichiometric amounts of electrons but you do need to drill a bunch of boreholes. if you just looked at "energy efficiency" you'd fail to amortize the drilling capex which is probably a bigger cost driver than electricity opex.

and fwiw estimates of LCOH by this process are $0.50-1.50/kg compared to maybe $3-6/kg for green H2. but these are obviously pie-in-the-sky NOAK figures and a technoeconomic analysis is only as good as the assumptions you feed into it. is it actually cost effective? there is only one way to know for sure, and these guys are gonna find out it's the hard way.

sure, and I'm saying that it's not a well-defined number because it's not a closed thermodynamic process. it's kinetically limited, so your H2 yield is a function of how much time you're willing to wait. it also obviously will depend on the type of rock, electrohydraulic fracturing parameters (pressure, voltage, pulse sequence) and so on. and in practice one of the biggest challenges in this field is actually capturing and collecting the hydrogen you stimulate, which is difficult to model and can depend on the precise geology and downhole microbiology. you simply can't compare it to electrolytic H2 on an atoms-per-joule basis.

critically, the electricity here is not actually directly breaking apart the water into hydrogen, so you can't directly calculate an energy efficiency like you can for electrolysis. this company is using electrohydraulic fracturing to shatter ultramafic rocks and thereby increase the rate of natural geochemical processes like serpentinization or the Schikorr reaction in which rocks react with water to produce geologic hydrogen. the actual source of the free energy that drives the reaction is partially reduced Fe(II) species in the crust (olivine, wüstite, etc) that can absorb an oxygen atom from water to produce free H2 (2 FeO + H2O -> Fe2O3 + H2).

something like 3-6% of the Earth's crust is ferrous Fe(II) so in principle the quantity of hydrogen that could be produced in this manner is something ungodly like 1e15 tons. but the problem is the natural rate of formation is very slow because it's rate-limited by low rock surface areas and slow formation of new rock faces. hence shattering rocks with electricity to increase the reaction rate.

source: I worked on the 2024 us govt research effort that funded these guys

https://arpa-e.energy.gov/news-and-events/news-and-insights/...

products of an asymmetric reaction performed without enantiomeric control can selectively catalyse the formation of more products with the same handedness -- this is called autocatalysis. so the first full reaction might produce a left-handed product (by chance) but that left-handed product will then cause future products to be preferentially left-handed. see the [Soai reaction](https://en.wikipedia.org/wiki/Soai_reaction?wprov=sfla1) for an example of this.

as mentioned by others this is conjectural but it is a popular (if somewhat unfalsifiable) explanation for homochirality

this is an absolutely valid Bayesian approach to this problem. sadly, this point is not even touched upon in this article, which deals solely with minutiae of the probability distributions (kurtosis, etc) of coins that are indeed fair.

to make a fair comparison here, you need to normalize per mole of metal. these enthalpies of formation are reported per mole of oxide, but there's twice as much Al per mole of Al2O3 than Ti in TiO2.

I don't think people are upset because they "got big", but because they were acquired by a corporation that signals a core shift in their ideals. If they were bought by Valve, or even Microsoft, I don't think there'd be nearly as much backlash -- because it's not that they're BIG, it's that Valve and Microsoft would not be pushing for a different market with their product (not to say they wouldn't later).

I seriously doubt the correlation between "liking porn" and "refusal to purchase a device that does not have official porn apps, especially considering I could stream porn from my phone or computer to my Chromecast just fine. In fact, if I'm being honest, I never install porn apps, even on devices that allow them, even if I intend on watching porn on them anyway.

New events? New sectors? New systems and subsystems?

New content from Chris Avellone?

Just playing devil's advocate here, but are you sure that the same sort of start-up culture pervaded the industry when these single-letter-NYSE companies formed (some over a century ago)? Don't you think that the presence of mass media (specifically internet presence) has greatly changed the importance of a name?

I have never seen this notation used, but perhaps it is mean to represent steradians (the unit of solid angle)?

You totally can get good at it, it's a skill like any other. I've won like 40 games out of 200 or so, and I'd say that I win about half of my games I decide to play past the first sector.

You just have to have a good feel for progression. Always fight as many ships as possible, and only leave the sector when the rebel fleet is riding your ass. Know which weapons, events, and upgrades are good, and roughly what order in which to get them.

I have played over 100 hours of FTL. Help me.

IIRC, the whole "99 cent pricing" paradigm originated not as a method to subtly reduce the apparent price of products, but as a way to force cashiers to give change for all purchases, and thus open the register so that all transactions could be recorded.

Of course, this practice is completely obsolete in online shopping, while the psychological pricing effect remains.

Screencaps:

http://puu.sh/2zwIE

http://puu.sh/2zwJJ

Maybe not viewing, but the article also talks quite a bit about filming, in which Glass has a concrete advantage.

Some bitcoin wallet clients, like Electrum, can recover your wallet from a seed that you can write down or email to yourself.

Electrum: http://electrum.org/

What did they teach?