Quantum Ampere Standard
https://www.nist.gov/noac/technology/current-and-voltage/quantum-ampere-standard
.
there also been research for defining a quantum volt and quantumly stable resistors

https://www.nist.gov/noac/technology/current-and-voltage
Quantum-based measurements for voltage and current are moving toward greater miniaturization

P.S. :
https://en.m.wikipedia.org/wiki/Quantum_Hall_effect
Quantum Hall effect →
Applications →
Electrical resistance standards :

(…) Later, the 2019 revision of the SI fixed exact values of h and e, resulting in an exact
R_K = h/e² = 25812.80745… Ω.

(this is precise to at least 10 significant digits)

Exploits of a Mom - xkcd
https://xkcd.com/327/

Hi ChatttGPT,
what’s the ethics of commenting a wall of text with your signature only at the very bottom ?

Hi,
Please notice you have to move (or cross post) this to another community (maybe [email protected] community) … because, once moderators see this post, they will delete it since it is not following the rules of this community !

Edit : whoops, i see you have already cross posted this elsewhere.

Same here … but still a bit concerned

Hey @[email protected], maybe you will want to reach out if you see this post. (Many here are a bit worried)

Take care 😌

Unite with the princess at the end would be great resolution of a game 😋 !

🕷️… 😌

Picture might be too big : there is a maximum number of kilobytes allowed.

🤣, welcome {( to ] ] !programmer_humor

:) + Bitcoin mining :
while(true{print(money);}

(…) came out of the blue and collided with the Stena Immaculate at 16 knots.

so, probably related to fog … … and the worst has been avoided :

(…) 36 people had been rescued, with one person taken to hospital.
(…) some jet fuel had leaked into the sea
(…) The cargo ship had been carrying 15 containers of the chemical sodium cyanide when it collided with the tanker.
(…) Sodium cyanide has a variety of commercial uses, from being used to plate metals to dye production. It is highly soluble in water (…)

You might have to create it : i made some more search and find nothing precisely as you asked.

Still i found this one is funny :
[email protected]

.

You are getting to this :

A + B → C (metastable and insoluble)
https://en.m.wikipedia.org/wiki/Classical_nucleation_theory
Classical nucleation theory …
Description …
Homogeneous nucleation …

C (metastable) → C(powder precipitate)

… unless you have heterogeneous nucleation
… first you have to eliminate all particle that can be nucleus on which powder can form, then,
… you need to stay away from homogeneous nucleation as described above.
… of course you have to provide a substrate on which C will nucleate, and grow,
… and this is why, in practice, (for large heterogeneous nucleated solids production) this process is very slow.

(…) there is also energy released in reaction, that can cover for decrease in surface energy (…)

Put this into equation or tell me how there is any meaning in this sentence.

You start with a powder ( then, maybe a chemical reaction or dissolution, whatever) and after that you don’t want to end up with a powder.

To go from powder to one solid object, the only energy change is the decrease of surface energy. … you must first see this.

You are trying to put together some words that you think might make sense, but clearly, i am very sorry, but you do not master this domain.
Al2O3 : one process that exists to crystallize this at about room temperature is aluminium oxide purification :
https://en.m.wikipedia.org/wiki/Bayer_process Bayer process

… and i told you why it doesn’t work. Alternatively, if you look at stalagmites, you are starting with dissolve salts with slow evaporation. Here you get a solid with good mechanical properties. But this process is very slow. Same idea applies to shells and bones.

if you are talking about cement (like in mortar or concrete), we already have a process to turn powder into solid ceramics at room temperature. Otherwise :

Ca(OH)₂ (powder) + CO₂ → CaCO₃ (powder)