Diamondoid Mechaosynthesis - one way ticket or not? => The most overlooked danger of APM?

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    • Diamondoid Mechaosynthesis - one way ticket or not? => The most overlooked danger of APM?

      In this video ( "Mechanosynthesis - Ralph Merkle & Robert Freitas" )
      R.Freitas says that you don’t take mechanosynthesized stuff apart again.
      See here: (Jump forward to 47:42)

      Guy in audience: "If I place a germanium incorrectly which tool do I use to get it off."
      R.Freitas "You don't."


      So the Set described in the there discussed tooltip paper
      ( molecularassembler.com/Papers/MinToolset.pdf )
      is not reversible in the bond-topology-state.
      The set was also not simulated in a way that maximizes reversibility in energy but instead in a way that
      makes it somewhat reliable at 300K (E_react = 0.40 eV gives P_react = 2*10^-7)
      and extremely reliable at 80K (E_react = 0.40 eV gives P_react = 5*10^-26 at)
      But most importantly the reactions where considered standalone and uncoupled to others.


      According to E.Drexler mechanosynthesis can be made to archive very high levels of energy reversibility:
      Nanosystems 13.3.7.b.
      ... reliable mechanochemical operations can in some instances approach thermodynamical reversibility in the limit of slow
      motion. ... ... The conditions for combining reliability and near reversibility are, however, quite stringent: reagent moieties must on encounter have structures favouring the initial structure, then be transformed smoothly into structures that, during separation, favour the product state by ~ 145 maJ (to meet the reliability standards assumed in the present chapter). ...


      * "smoothly" I think means forces times movements must be captured in the machine phase background. Holding against pulling force - preventing ringing snapping.
      * Furthermore I think that one needs to couple multiple reactions with E_react-one<<kB*T energy-loss per deposition/abstraction
      together to E_react-all>kB*T as a whole to prevent the single reactions from running backwards.

      I made a 3D model for visualizing the qualitative progression of the energy wells that is necessary for a energetically reversible mechanosynthetic operation. This model is quantitatively disconnect from any particular physical process like e.g. hydrogen abstraction.
      apm.bplaced.net/w/index.php?ti…nosynthesis_principle.jpg


      The question is:
      Can one imply from energetical reversibility to bond-topological reversibility?


      Surely it seems difficult to rip out a carbon from the centre of a flat diamond say 111 surface.
      But if the atomically flat plane does not have macroscopic size one can start from the edges where less than three of four bonds are inaccessible. Astoundingly there was an AFM experiment conducted where on an atomically flat surface buried tin atoms where controllably flipped with silicon atoms and vice versa (surface-to-tip).
      uam.es/gruposinv/spmth/papers/…gy_4_803_Custance_AFM.pdf
      They used a lot of tapping and akin to what E.Drexler describes as "conditional repetition"


      I think to find an answer to this question is highly relevant for recycling (in the advanced end of the technology spectrum)
      The official nano-factory video says something like "the only waste products are clean water clean air and heat".
      But what about the product itself once its microcomponents become obsolete?


      If mechanosynthesis can't be made bond-topologically reversible from the early on start the only way to get rid of obsolete versions would be by:
      * burning them - only possible if they don’t form slack due to incorporated Si,Al,Ti,...
      * dissolving them (Sodium beam treatment, Acids, ...)
      If even that will not be done we might sink deeply into diamondoid waste.


      I think that might be the most severe and most overlooked danger of APM.
    • lsuess wrote:

      So the Set described in the there discussed tooltip paper ( molecularassembler.com/Papers/MinToolset.pdf ) is not reversible in the bond-topology-state.

      Since the goal of the study did not include the additional burden of that requirement, I am not surprised. Efficient reversibility would see a longer-term goal.

      lsuess wrote:

      I made a 3D model for visualizing the qualitative progression of the energy wells that is necessary for a energetically reversible mechanosynthetic operation. This model is quantitatively disconnect from any particular physical process like e.g. hydrogen abstraction.
      apm.bplaced.net/w/index.php?ti…nosynthesis_principle.jpg

      I'm afraid I don't know what the image is supposed to be showing me. None of the axis are labeled - do you have some additional context or discussion somewhere?


      lsuess wrote:

      If mechanosynthesis can't be made bond-topologically reversible from the early on start the only way to get rid of obsolete versions would be by:
      * burning them - only possible if they don’t form slack due to incorporated Si,Al,Ti,...
      * dissolving them (Sodium beam treatment, Acids, ...)
      If even that will not be done we might sink deeply into diamondoid waste.


      I think that might be the most severe and most overlooked danger of APM.

      I'm probably missing something, but I don't see how one can draw any inference about future tools from the first set of invented tools for molecular carbon mechanical synthesis. I skimmed sections 13.3.7, 13.3.8, and 8.5.2 of Nanosystems and it does not look to me like there are any dangers. Even if none of the released binding energy were stored for later re-use, the universe is awash in thermonuclear energy. I think it is something of a technical oddity that so much of it is temporarily inaccessible. Energetically inefficient nanotech production would still be, on a relative scale, far more efficient than current tech production.
    • Jim Logajan wrote:

      I'm afraid I don't know what the image is supposed to be showing me. None of the axis are labeled - do you have some additional context or discussion somewhere?

      I made an annotated version now.
      (I've attached the original lossless vector graphics (*.svg) in zipped form -- *.svg not allowed)
      Files
    • Jim Logajan wrote:

      I'm probably missing something, but I don't see how one can draw any inference about future tools from the first set of invented tools for molecular carbon mechanical synthesis. I skimmed sections 13.3.7, 13.3.8, and 8.5.2 of Nanosystems and it does not look to me like there are any dangers. Even if none of the released binding energy were stored for later re-use, the universe is awash in thermonuclear energy. I think it is something of a technical oddity that so much of it is temporarily inaccessible. Energetically inefficient nanotech production would still be, on a relative scale, far more efficient than current tech production.
      Ok, I see that I missed some important points in my initial post.

      1)
      I do not infer a limitation on future toolsets based on this early toolset-feasability analysis.
      In fact I try to show the contrary. I reckon that the "proven" possibility for energetically reversible mechanosyntheis should imply the possibility of bond-topological reversible mechanosynthesis.
      So that it even makes sense to talk about bond-topological reversible mechanosyntheis (dis-assembly) - (establishing discussion basis)

      The point I'm trying to make is that in a competitive market early attempts are unlikely to wait with production till recycling is perfectly figured out.
      And that bond-topological reversible mechanosynthesis (by coupling separate mechanosynthetic reactions together in the background and applying the illustrated principle) looks to be a lot more difficult to archive than bond-topological irreversible mechanosyntheis. There's the additional difficulty that I haven't mentioned yet that one has to do more than the easier open-loop-control to take stuff apart that has been damaged (radiation,heat,...).

      In short what I am really worried about is the temporal sequence of development.
      In the early development stages (DNA, proteins) bond-topological-irreversibility is irrelevant since bio-organisms can do the recycling for us. But when we start to arrive at the diamondoid stuff (swimming like plastic or even floating in the air) and arrive at high production volumes before the cleanup is fully figured out we might be in for trouble - damaging nature.

      I have no clue how much influence we will have on the temporal sequence of development - I'd guess rather little.
      What I think should be easier to archive than bond-topological reversible mechanosynthesis is making nanosystems of many
      reusable small parts instead of fusing them together to a single monolithic crystal.
      This way diamondoid products can at least by recycled to themselves for a while.

      2)
      I do not think high energy consumption prevents recycling.
      Actually the contrary. The fact that the atom by atom assembly step is the most energy consuming (because of most surface area not because any lack of efficiency) gives a strong incentive to make bigger parts ("crystolecules") reusable. That is: not fuse them all together to a single macroscopic block. Also production by recycling of "crystolecules" (~<32nm) or even bigger "microcomponents" (~<1um) should be much faster since less waste heat has to be removed.

      X)
      I think there's a recurring pattern in history that stuff gets produced in masses when it can't yet be disposed of and that it then produces problems due to its piling up. Side note: Beside human civilization also nature provides such examples albeit on much bigger timescales. Examples are "the great oxygenation event" and "the lignin catastrophy" (less known)
      I think the widespread belief (under the ones that even know about APM) that nanofactories are except from that pattern might cause problems. Blindness for the possible danger waste. What will really happen all depends at which capabilities we arrive when.

      I think in any case we'll need to have waste management guidelines.
      I'm collecting info about recycling on my wiki:
      apm.bplaced.net/w/index.php?title=Recycling

      ---------------------


      lsuess wrote:

      Can one imply from energetically reversibility to bond-topological reversibility?
      ....
      I think to find an answer to this question is highly relevant for recycling (in the advanced end of the technology spectrum)

      I wrote nonsense there. - Your comment helped me to reformulate what I really meant:
      How much effort will it take to archive bond-topological reversibility?
      Given that the possibility of energetically reversibility should imply the possibility of bond-topological reversibility.
      I think to find an answer to this question is highly relevant for recycling (in the beginning of the advanced end of the technology spectrum)

      The post was edited 1 time, last by lsuess: removed meaningless formating string ().

    • Basically, as long as we achieve molecular nanotechnology, and mechanosynthesis, we don't have to concern ourselves with material waste from it. Atoms are Atoms, Molecules are Molecules. Any form of diamondoid or other MNT "waste" can be broken down through various methods. The beauty of the process is that it is reversible, and can be dealt with.

      Some speak of the issue of waste heat. That would be a much more difficult prospect because thermodynamic laws do not allow you to break down waste heat. However, we can always radiate it out into space, like the Earth does with solar energy heat.
    • I guess you assume a level of molecular nanotechnology, and mechanosynthesis where you can place every element of the periodic table in any practical way physical law permits and pick atoms from any local molecular environment.

      Long before that level of capability will be reached earlier forms of high throughput advanced molecular nanotechnology, and mechanosynthesis
      (e.g. synthesis of diamond and graphene) will be available. Those forms of mechanosynthesis are likely to be rather limited in the way they can place/handle atoms. (Side-note: That limitedness does not transfer to the earlier products - completely different behaving mechanical metamaterials can all use the same base material.)

      Of course on the nanoscale atom and molecule bonding topology is always fundamentally reversible. But that does not mean that implementing the backward process technically is as easy as implementing the forward process. Actually there a number of reasons why implementing the backward process (disassembly) is much harder than the forward process (assembly).

      Since mechanosynthesis is basically a blind open loop control assembly process (heavily relying on extremely low error rates) once some in the past mechanosynthesized crystal-molecule assemblies have incurred radiation or thermal damage, mechanosynthetic disassembly can't be performed by simply running a nanofactory in reverse - this would just end in a mess. Even if the product crystal-molecules are damage free it's still difficult. Some assembly steps may have way higher error rates in reverse (that's where energetic reversibility comes into play).

      So I'm concerned about giant mountains of diamondoid waste piling up not because recycling is fundamentally impossible (which is certainly wrong)
      but because I see a timespan coming in which it is technically WAY easier (and economically cheaper) to just create systems for making diamondoid crystal-molecules by mechanosynthesis instead of creating mechanosynthesis systems that are also capable of taking diamondoid crystal-molecules apart.

      (Re-usage of microcomponents may mend that problem but only to a degree since they may become obsolete - analog to software.)