Also just another thing that might be interesting:
Check out ‘intermediate temperature storage’, the idea of storing at a slightly warmer than liquid nitrogen temps (-130′C as opposed to −196′C) is a good idea in order to avoid any fracturing*. This is right near the glass transition temp, so no nucleation can proceed.
Tricky part is there aren’t any practical scalable chemicals that have a handy phase change near −130′C, (in the same way that liquid nitrogen does at −196′C) so any system to keep patients there would have to be engineered as a custom electrically controlled device, rather than a simple vat of liquid.
Not impossible, but adds a lot of compexity. They might end up doing it in a few years by putting a dewar in a dewar, and making a robust heater that will failsafe down to LN2 if there’s any problem.
*Personally I’m not concerned with fracturing, it seems like a very information-preserving change compared to everything else.
Tricky part is there aren’t any practical scalable chemicals that have a handy phase change near −130′C, (in the same way that liquid nitrogen does at −196′C) so any system to keep patients there would have to be engineered as a custom electrically controlled device, rather than a simple vat of liquid.
Phase changes are also pressure dependent; it would be odd if 1 atm just happened to be optimal for cryonics. Presumably substances have different temperature/pressure curves and there might be a thermal/pressure path that avoids ice crystal formation but ends up below the glass transition temperature.
Also just another thing that might be interesting:
Check out ‘intermediate temperature storage’, the idea of storing at a slightly warmer than liquid nitrogen temps (-130′C as opposed to −196′C) is a good idea in order to avoid any fracturing*. This is right near the glass transition temp, so no nucleation can proceed.
Tricky part is there aren’t any practical scalable chemicals that have a handy phase change near −130′C, (in the same way that liquid nitrogen does at −196′C) so any system to keep patients there would have to be engineered as a custom electrically controlled device, rather than a simple vat of liquid.
Not impossible, but adds a lot of compexity. They might end up doing it in a few years by putting a dewar in a dewar, and making a robust heater that will failsafe down to LN2 if there’s any problem.
*Personally I’m not concerned with fracturing, it seems like a very information-preserving change compared to everything else.
Phase changes are also pressure dependent; it would be odd if 1 atm just happened to be optimal for cryonics. Presumably substances have different temperature/pressure curves and there might be a thermal/pressure path that avoids ice crystal formation but ends up below the glass transition temperature.
1 atm pressure has the advantage of costing nothing and requiring no equipment to maintain.