High pressure
In advanced gem-gum technology extremely high pressures can be easily induced by simple means of mechanical advantage.
Contents
Why high pressures don't cause cracking on the nanoscale
Since most crystolecules are fully atomically precise and faultless there are no points where cracks can start early. Thus albeit being gemstones (which in our usual macroscale experience are rather brittle) they can be bent in the two digit percentual range. At the nanoscale the whole theoretical strength of the material can be exploited.
Mechanosynthesis is all about high pressure
By means of mechanical transmissions and cones pressures (and tensions) can be increased all the way to breaking point of the chemical bonds of the strongest existing materials (e.g. flawless diamond). After all this is what the process of mechanosynthesis is all about.
By conceptually widening the tips of the tool holder cones for mechanosynthesis one could break more bonds at once. A stiff diamond rod between to tips can be bent all the way to the theoretical limit (a little more if cold).
What about high pressures at the macroscale
Large conglomerates of crystolecules will of course have some crystolecules inside which have mild to severe faults. But due to the nature of their connection featuring shape locking cracks in crystolecules are stopped immediately at their interlocking interfaces. Thus even at the macroscale still a good fraction of the theoretical strength of the material can be exploited.
Applications
Applications of high pressure in the nanoscale
By keeping extremely high pressures in localized patches products containing these can be completely safe at the macroscale.
Inclusion of slight strains can help simplifying design of crystolecules - example: strained shell sleeve bearing
Pressure can have very strong effects on various physical properties. It can have a similar effect to low temperature. This gives several opportunities to reducing civilizations dependency on scarce elements.
- Magnetism in elements that don't normally show it. (carbon)
- Superconductivity at higher temperatures than normal (maybe even room temperature?)
(highly compressed noble gasses in channels as wires?) - On the single bond level highly controlled application of extreme pressures makes noble metals for catalysis (which much more limited capabilities) obsolete. (See: Mechanosynthesis)
Applications of high pressure in the macroscale
Obviously monolithic macroscopic tanks filled with extreme pressures naturally pose a considerable risk. While pretty safe when undisturbed exposure to external force can easily lead to a violent explosion. So unless absolutely necessary one will likely want to avoid such tanks.
In cases where surface area needs to be minimized.
- barely macroscopic (µm to mm scale): capsule transport of liquid density hydrogen at room temperature
- very big tanks but usually at rather low pressures: gem-gum balloon products
- in deep mining and deep drilling
- exploration of subsurface oceans in the solar system
The limits to bending
One should keep an eye on the average stress strain energy of all the nanomachinery in a product taken together such that one does not accidentally produce combustion supporting or even explosive products.
When increasing stress and strain in crystolecules further and further one successively looses:
- first chemical stability (ok when isolated in a vacuum as for most machinery the case)
- then thermal stability (we are very near the limit! – ok when cooled down enough permanently)
- and finally mechanical stability (fracture)
Actually testing the fracture of simple crystolecules in a controlled fashion should be very interesting.
The limits to pressure resistance
Machines with moving parts and internal material transport of some sort usually need at least some some amount of voids inside. These voids can be very small though. Probably so small that the limiting factor is not the number and size of the voids but instead the pressure that the actual solid crystal structure can take before it gets crushed and undergoes a phase transition.
So then hardening against high pressure involves choosing materials that do not undergo a phase transition under the expectable pressures. Like e.g. when it comes to silicon dioxide: Instead of quartz one might want go for its metastable high pressure polymorph Stishovite as main structural material.
Another issue is that electronic properties quite dramatically change when pressures become extreme (there are big band-gap shifts and such) so wile electronic system may not get destroyed they may get temporarily incapacitated. Possible solutions to this could be:
- isolated electronic components from the pressure (treat them as voids)
- designed special electronics that only starts working at these high pressures (reaching superconductivity may be easier btw)
- do these things in a nanomechanical rather than nanoelectronical
- ...
