Posts by lsuess

    I've now detangled the core convergent assembly decisions in Chris Phoenix's
    "Design of a Primitive Nanofactory" document.

    I've separated it from other IMO less important decisions about geometric and other things.
    Here are the relevant crop-outs:

    quote: Chris (CHRISPHOENIX)

    4. Nanofactory Architecture
    ... The current design, ... uses only one block from each fabricator per product cycle. This implies that each stage will receive all its blocks in parallel. In general, then, each stage must have either eight (non-redundant) or nine or ten (redundant) inputs. (The first gathering stage has only four inputs, to compensate for the eighteen inputs of the final stage in the production module; see below.) ... A square of nine fabricators (one redundant) forms a stage. ... Likewise, a square of nine of these stages forms the next stage. This continues through several levels; in the current design, four levels is chosen ... unlike Merkle's design, each input port delivers only one block per product cycle instead of two. ...

    4.3. Gathering stages
    ... product assembly requires 14 further assembly stages where each stage assembles 64 sub-blocks to produce eight product blocks. ... A final stage, ... assembles eight ... sub-blocks (per product cycle) to produce the final product. Note that the first stage in the Figure is not an assembly stage, but serves only to gather 8 sub-blocks for delivery to the next stage, since each production module makes only two blocks per product cycle. Each assembly stage gathers 64 sub-blocks from substages, assembles them within the assembly/delivery tube, and delivers the 8 assembled blocks to the superstage.

    Since its a bit tricky to read out the specifics about the "welding" between the lower stages and upper stages with the frame of reference shifting around I'll reformulate it.
    I hope I can make it more obvious that there is no discontinuity or convergent-assembly-character-change.

    The four 4 lower stages (including the fabricators at the bottom) make up a production module which has 8(+1*) outputs
    Now 2 production modules
    with each 8(+1*)subblocks = 1fullblock of outputs
    make 16(+2*)subblocks = 2fullblocks of output together.
    This is a production module pair.
    The first(isn't it the only one) gathering stage takes four production module pairs as inputs and thus gets 16*4=64subblocks which equates to 2*4=8fullblocks.
    Those do not get assembled here yet. This does not change the character of the convergent assembly though. It makes just a small local delay.
    Stages further up take 8*8=64fullblocks and assemble them to 8biggerfullblocks
    (Did I get that right?)

    As far as I can see all the these stages with identical convergent assembly characteristic can simply be added up. This makes all in all 4+14=16Stages.
    Assuming a throughput capacity (not throughput!) of 1kg per second at the topmost stage (gross underestimation) calculating downwards toward the stage just before the fabricators leads to a throughput capacity of 2^16kg~=64000kg/second - wow. The fabricators at the bottom though won't come even close to 1kg per second of throughput. I see a major mismatch everywhere. I hope this formulation makes more clear what I'm trying to get at than the abstract formulation that I've given above.

    I think it would be great to have a clean separation of convergent assembly parameters and geometric design.
    This way one could just dial in the parameters (and step-sizes) and out comes an auto-generated 3D model.
    Practical designs will probably only be viewable in their entirety (over wide scales) with visualization methods similar to the one I've outlined above.

    quote: Lukas (LSUESS)

    What also bothers me is that although this is supposed to be a practical design it adheres rather closely to the very small side-length doubling steps which I've tried to argue against above.
    Ooops I've missed that line:

    quote: Chris (CHRISPHOENIX)

    The design can be compacted somewhat if multiple convergent assembly stages can be combined; such optimization is beyond the scope of this paper.

    Here's my personal opinion on existing crystolecule designs.
    Just a gut feeling:

    10 ... will probably work without redesign
    1 ... will probably need major re-modelling
    X ... I doubt this makes sense

    universal joint: 9/10
    E. Drexlers big bearing 9/10
    spur gear systems: 8/10
    differential: 7/10
    planetary gearboxes 7/10
    neon pump: 5/10
    acetylene sorting pump: 1/10
    super-tiny steward platform inspired manipulator: X/10

    Some preceding information:
    With the term "crystolecules" I'm going to refer to the diamondoid molecular machine elements of advanced prospective nanosystems.

    Before I start I need to take a step back:
    I suspect the nanorex website went down[1] because of the drop in funding due to the NNI censorship incident. Is that correct?
    I doubt it would be expensive to at least keep it as an read only archive.
    But I guess there is another reason for why it was not put up again.
    Namely: The animations of crystolecules

    Check out this blogpost:
    "Nanomachines: How the Videos Lie to Scientists"…videos-lie-to-scientists/


    "By now, many scientists have seen videos of molecular-scale mechanical devices like the one shown here, and I have no way to know how many have concluded that the devices are a lot of rubbish ... If only all these videos could be recalled and upgraded in the way shown below ... In short, the videos seem to show devices in which the drag of sliding friction would be enormous, and the rate of heating would be astronomical. ... What the video shows isn’t vibrational motion ... but instead a stroboscopic sample of atomic positions ... "
    here is the misleading stroboscopic illusion:
    here is a more realistic visualization:
    I feel the current situation makes it increasingly difficult to find the original files. I don't think hiding those animations and waiting till there are better methods for rendering crystolecules is a good idea. Instead I think it should suffice to add the note "beware of the stroboscopic illusion" (ideally directly onto the pixel-data so it is safely preserved).
    Do you agree / disagree / ... ?

    There is a second trapdoor in those depictions that might lead to false assumptions and quick dismissal.
    E. Drexler doesn't note it in the aforementioned blogpost but has AFAIK mentioned this elsewhere (in fragments?).
    It is about the misjudgment of the stability of surfaces.

    While hydrogen terminated diamond surfaces (that do not even touch each other) do not pose so much of a problem (there are even detailed papers analyzing diamond surface stability on small particles by now) many crystolecules feature surfaces with fancy passivations containing other elements that may introduce significant internal stresses.

    Since scientists are currently forced to work in reactive environments (including water, air and even UHV) they tend to judge chemical stability more than thermal stability. But in the envisioned working environment (a practically perfect vacuum PPV) thermal stability alone suffices.
    Thermal stability alone is a much much weaker requirement than chemical stability against aggressive media thus the range of usable structures gets a lot bigger in a PPV environment. [2]

    Here are some examples:

    Lesser subject to mislead criticism: purely hydrocarbon universal joint:
    certainly stable 20°C Vacuum AND certainly stable in aggressive chemical media.
    Stronger subject to mislead criticism: alternatively passivated universal joint:
    certainly stable 20°C Vacuum BUT stability in chemical aggressive media (including water and air) not yet investigated.
    Stronger subject to mislead criticism: Drexlers famous big bearing!
    I made this 3D printable version :)
    The data is here:
    If you want one too you can order it here at shapeways for net cost price.…g-inner-shell-part-1-of-2…g-outer-shell-part-2-of-2

    Lesser subject to mislead criticism: "DMSE-Tetrapod ("crystolecule")" (of my own design)…-tetrapod-armchair-warped…27QRE/diamondoid-tetrapod

    There is someone planning to gamify something nanofactory related (crystolecule design?).
    Column bottom left here:
    I doubt this is going anywhere though see: and judge for yourself.
    I'd like to think that gamifying crystolecule design is a good idea.
    Do you think it is practicably possible ... ?
    Since this is "future backward" work (analog to top down & bottom up) I think one needs to be especially careful considering you let people loose on those problems who have no prior knowledge at all.
    Here's one example for a possible pitfall:
    Putting too much oxygen near carbon.
    If you replace all the silicon atoms in normal Quartz (SiO2/silicon dioxide) with carbon you'd end up with something like "carbon quartz". While this material is probably thermally stable at room temperature (and super hard) it is very likely to be a highly potent explosive almost like sp3-nitrogen (solid at 20°C 1bar).
    Also the last published nanoengineer-1 version does not correctly simulate electron deficiency bonds! You can check that by trying to enclosing a BN pair into a tiny diamond crystal. The result is waay to much repulsion between B and N. It's almost as if you had included two nitrogens atoms resulting in massive overlap repulsion between the two electron lone pairs. To prevent flawed designs emerging from this either boron and aluminium need to be made unavailable or the software needs to be extended to be able to handle these correctly (Is this possible with mere mass spring models?)

    If gamifying crystolecules (among other things) works out we might really build up quite a bit of an
    "left foot theoretical scientific overhang" like J. Storrs Hall mentions in this video:
    I think this video needs more views. Please share it.
    By now though I personally don't think we have so great of an overhang yet but that may change.

    ps: (I'll edit in the images once I've dug them out - done)

    [1] Does anyone here know whether the nanorex website with its nanoengineer-1 development wiki still exist?
    Here's the old address - almost dead link (intended):…index.php?title=Main_Page
    As far as I can remember there was some interesting stuff in there. So interesting that I even made printouts. Maybe I'll find them ...

    [2] The only restriction is that everything on diamondoid atomically precise products that faces outward IS chemically stable so there are a lot less options available.
    Related note regarding recycling: (a speculative idea)
    Diamond does not dissolve in water or rot away so it has good potential to pollute the environment if it somehow manages to leave macroscopic chunks of machine phase.
    Here is an idea how to make APM products biodegradable:
    Instead of a thin diamond shell that is almost indestructible by all means of weathering and all of natures bio-attacks one adds a rather thick sacrificial layer that slowly dissolves or rubs off. This makes the hull. If the product is intended for longer use it may be replenishable from the inside. (Microcomponent dis-assembly will become harder with undefined outermost surfaces though)
    One diamondoid material (of several that use abundant elements exclusively) that may be usable for this is I think periclase (= Magnesium Oxide = MgO). It is a salt that does only very slowly dissolve in water. If the whole product (not a nanofactory - rather drinking bottles and the other stuff that usually ends up swimming in the sea) shall be biodegradable one must forgo using diamond for all its internal parts too.

    Periclase wont work well for bearings though - anyone any idea whether it is possible to sensibly passivate such a salt for bearing interfaces - it should be usable for structural elements though. Quartz (a substance nature knows well) might be better usable for bearing surfaces. Oxygen bridges make it much more porous than C, Si, SiC and similar compounds though.
    Btw I collect and classify many materials that may be suitable for advanced nano-fabrication here:
    One of my favorites is the yet mysterious "beta carbon nitride" (no big chunks made yet)
    Which is what you get when you make the most out of air.

    Attached files

    There's this common misconception that natural systems that use diffusion transport are fundamentally more efficient than systems that do not use thermal motion in that way. In reality though it seems machine phase system will fare better than enzymatic diffusion based systems could ever do though.

    I was pointed there by this blog entry of E.Drexler:


    "... (note: transporting molecules by diffusion down a concentration gradient is not cost-free — it pays the same free-energy cost as any other way of driving the motion of molecules). ...

    And a lecture about "Molecular Biology of the Cell"…ter=2014W&courseNr=134201
    About the energy flows in living systems (ATP, NADH, ion gradients, ...)

    What is overlooked is that while the diffusion-transport (in cell biology) is free in energy expenditure one has to expend/thermalize energy packets at critical points (waiting positions?) in the chain of reactions that are significantly bigger than kBT (kB..Bolzmann constant, T..temperature in Kelvin). This is necessary to ensure that the system is irreversibly moving in the desired forward direction (often formulated as having a defined "arrow of time"). In diffusive systems with enzymes in solution reactions are mostly unconnected* in sequence (time) and pathway (space). Because of this unconnectedness the kBT energy packets** can't be shared over a greater number of reactions.

    * still more than one might think
    ** not a quantas!!

    In non diffusive stiff machine phase system one in contrast can connect multiple mechanosynthesis mills in the background e.g. via rotating shafts (space) and shift their processing cycle slightly in phase (time) this should allow sharing of the necessary energy devaluation (as mentioned before for a defined process direction) over a much greater amount of reactions.
    (By combining streams suitably maybe even many of the aforementioned waiting positions can be cheated!)
    Furthermore machine phase systems can be heavily cooled making a single packet of kBT much smaller. In a diffusive system cooling would just freeze the solvent preventing the whole system from working.
    This sharing of a single energy devaluation step combined with some cooling should by far outweigh the low superlubricative friction which is not present in diffusive systems.

    Considering E.Drexlers comment in the aforementioned blog enty he has probably figured all this out.
    It does not seem he has written it down anywhere publicly though.
    I think this aspect of APM systems deserves more attention so I'm bringing it up here.

    Investigation is needed: (Have you guys any ideas here?)
    Needed are methods for the calculation / rough estimation for at which points in space and time there still needs to be expenditure of energy sufficiently>kBT in stiff machine phase systems?

    Here are some details that may help:

    First there is the parameter of allowed amount of random backward run in mechanosynthesis processes (a whole nanofactory subsystem running backward "in time").
    Then there are internal flexibilities in e.g. aforementioned rotating shafts in the background. These make quantum modes of
    torsion oscillations (gear interfaces will complicate matters). Those modes will likely house several kBT (as phonons) at room temperature (not too hard to check). Even with those many kBT in the interconnected-background-axle-system single units sufficiently>>kBT might be shareable due to low amplitudes of added up modes in stiff systems.
    (Will spacial sharing work over the whole makro-system of a nanofactory ?! That would be way more than necessary!)

    Irrelevant side-note: I doubt one will get down to the ground state at any practical temperatures. Oscillation energy quanta are usually way bigger than rotation quanta but those axle systems will contain millions of atoms.
    Relevant side-note: All this only makes sense if beside reversible logic also reversible actuators are designed and applied (energy recuperation). I'am not aware on any works that target and analyze these. I think this is an interesting topic to investigate too (material for another discussion). Reversible actuators should be especially easy in the molecular mills that do not change their routine cycle. But it should also be possible in general purpose assembly since the program is known.

    Slightly off-topic:

    • Also in machine phase systems - while certainly not efficient - local spots in space or time can (if necessary) truly handle motions at the speed of sound which is rather impossible in diffusive systems.
    • Despite their relative inefficiency diffusive systems seem to be incredibly useful for early steps. Efficiency is meaningless if is not buildable. E. Drexler writes in the aforementioned blog post:


    "... While early systems can (and likely will) operate in fluids, considerations of efficiency will favor a move to well-ordered, fluid-free systems."

    ps: This is highly uncharted territory.
    There is a high probability that I'm talking complete bogus here.
    If you spot anything suspicious please tell.

    Luckily its called "Sci-Nanotech" which is used nowhere else (brand like). If the forum where called more bland and generic "The Nanotechnology Forum" that would IMO pose a problem.

    About that it is necessary to use common terms in public awareness work - agree -
    The serious problem is that searching with the term "nanotechnology" has become like moving a magnet ball through an iron maze on a balancing board (excuse the analogy).
    I think the usefulness of the term "nanotechnology" has already dropped to the level of the lesser known alternatives (but out of this different reason)

    People who are seriously searching will hopefully come across other terms then just "nanotechnology".
    (another keyword would be: "molecular sciences")

    • 0 request for forum "folders" ... remaining in general
    • 0 Deathly quiet here ... remaining
    • 2 Vacuum Lockout - concepts old and new ... far goal
    • 0 Thank you, Jim! ... remaining
    • 2 Nanofactory block diagram ... far goal
    • 3 Electrostatic focusing on the atomic scale ... applications
    • 0 Youtube+APM again ... remaining
    • 2 convergent assembly and its visualization ... far goal
    • 0 DARPA Robotics Challenge Finals, 2015 ... >remaining< / (far goal) / (misc)
    • 0 Members List ... remaining
    • 0 Drexler Joins Nanotronics ... remaining
    • 6 Quantum computers ... misc (decision based on initial post not thread title)
    • 0 A Poll to Stimulate Discussions ... remaining (<- spelling error "Pole" corrected)
    • 4 Synthetic chemistry machine ... path
    • 4 When will the Foresight Grand Prize will be claimed? ... path
    • 4 Nanoscale magnets to actuate DNA machines? ... path
    • 0 YouTube Nanotech show? ... remaining
    • edit1: 1 diffusion transport efficiency misconception ... basics
    • edit2: 2 the Disappearance of the Crystolecules ... far goal
    • 5 impacts ... no threads yet

    I think this was rather easy to decide/classify.

    I've based those categories on the 200+ slides I've made that I've mentioned in the "Youtube+APM" thread - so I do have put quite some thought in them.
    But you're right - its unclear how posters will behave.

    Hello :)

    Well, "molecular nanotechology" has attained quite some usage (easily checkable by google image search - in quotes!) and I think that Eric Drexler has at least some influence on terminology so I'am not sure whether "Atomically precise manufacturing" will or will not be adopted.

    The issue is that people tend to cling to a save haven where they think they have some knowledge but this always invariably leads conversations astray.
    E.Drexler tries to condense this down here:…-kinds-of-nanotechnology/
    He writes:


    I count five kinds of nanotechnology, ... This situation makes it extraordinarily difficult to have a productive conversation about what really matters.

    Other terms certainly cannot be used in an introduction or as a tag for others to find it. Thats why I wrote:


    " ... - new terms are not usable for search keywords though - ... "


    Vacuum lockout is one of the most essential steps in advanced diamondoid nanofactories. If you watch the "productive nanosystems" video attentively though you'll realize that this important step is conveniently omitted. Why is that? I vaguely suspect the reason for this sore omission is that there aren't any simple and convincing ideas for doing this yet.

    Also in "Radical Abundance" the vacuum lockout process is mentioned rather briefly.
    In "Radical Abundance" page149 chapter10 Eric Drexler writes:


    "...The door to the right then unseals and opens, and a car moves out into the receiving area,sealed in what looks like a plastic sleeve. A moment after the door releases, the sleeve is pulled back for recycling and the process is done. (This exit maneuver is part of a cycle that prevents contaminants from entering when the product exits.) ... Instead, at the touch of another button, the car rolls into a neighboring machine where its parts are recycled." I think I've somewhere read about an idea (which is the most up to date one - I think) keeping practically perfect vacuum right up to the macro-scale and extruding the product in a sausage shaped balloon through a tube that seals atomically tight. -- I very much dislike this idea because:
    * recycling (of microcomponents) seems a lot more difficult
    * not using the small chamber effect
    * it is a single point of failure for the whole factory
    * probably not relevant: opening gap through hard crash or mishandling => scratches through dirt or vacuum breach

    Wrapped up I perceive a lack of convincing vacuum lockout methods.
    Thus I searched for a more elegant solution.
    Here is what I came up with for a new vacuum lockout concept for nanofactories:
    Please share your thoughts!
    (details: )
    I plan to publish the 3D-model when it is in a 3D-printable state.
    Here's a little preview video of the operation process:

    I think the best place in the convergent assembly chain to include these devices is just before the microcomponents assembly step. At this point all open radicals are already passivated and you can do further assembly by exclusive shape locking (& VdW force) in a clean but reactive gas environment.

    Beside the aforementioned "sausage lockout" concept basically all of the ideas that are still flowing around are I believe remnants from the time when assemblers where still considered a valid approach.

    4.11.2 Merkle Replicating Brick Assembler (1995-1997)
    * extruding block concept:
    * the same with details:
    * throwaway scrolled up graphite hull concept:

    I think because of the lack of new ideas for nanofactories assembler targeted concepts made it into the nanofactory targeted Book Nanosystems:
    * Nanosystems Page 417 figure 14.2 -- elastic balloon extending
    * Nanosystems Page 417 figure 14.3 -- sliding blocks
    (Afaik there was some work done on that sliding cube concept by Tihamer (Tee) Toth-Fejel)

    Related too vacuum lockout I once made this model of a bellow that could be made from diamondoid material. (Image Public Domain)
    Assemblers (for which this was originally intended for) are outdated now but maybe this can be used for something else.
    The surfaces in this model are kept parallel to the main crystallographic axes.
    Sadly I've lost 3D-data of the newest version of the openscad file. :(

    Attached files

    >> JimL: "Unless it involves a [molecular] wardrobe malfunction, I'm not sure what would compel anyone to view such videos." (from an earlier thread)
    >> Snowman: "Orrrrrrr do you mean videos about nanotechnology? If so, have the hot babes wear very very very small bikinis."

    If you're so hell bent on sex-sells how about that:

    The key to reliable success when trying to reach the desired reaction:

    • stiff tools
    • forceful and skillful interaction
    • well bond partners
    • pressing in repeatedly

    Mechanosynthesis is hot!

    Bad joke aside - the key to generating interest is quality content (in small chunks).
    One has to archive the miracle of high density information mated with first class entertainment.

    >> Snowman: "Or...r, just do simply explanation videos. "What's nanotechnology?" ... "

    I think we should not try to reclaim the term "nanotechnology".
    A term that was annexed from others** because it lacks specificity.
    (**people doing unrelated research on non atomically precise nano-scale stuff)
    In his new Book "Radical Abundance" Eric Drexler tried to introduce the new term "atomically precise manufacturing (APM)" shunning the term he used earlier namely "molecular nanotechnology". IMO "atomically precise manufacturing" is too much of a mouthful. I'm not sure it will find widespread use.
    If we want to refer to the advanced diamondoid stuff only (explicitly excluding e.g. DNA origami) we still need another term. By composing E.Drexlers terminology we would arrive at "diamondoid APM" - even more of a mouthful. A term I came up with recently was "Gemstone Meta-material Technology" or more catchy and exemplary "Gem-Gum Technology" - new terms are not usable for search keywords though - any further ideas for terms are welcome.
    I collect existing terminology and ideas for new terms on this page:

    >> Snowman: "Or...r, just do simply explanation videos. ... "What's a nanite?" "

    There are a lot of terms for more or less free floating nanorobots around already but most of them (including "nanite") do not concretize on what exactly they mean. They are just chosen to sound cool in a SciFi setting.
    Instead they spawn faulty associations with living cells/bugs. Common are:

    • faulty assumption of existence of mutations
    • faulty assumption of capability of "digesting" a very wide variety of "food"
    • faulty assumption of the necessity that they must be capable of self replication

    Major exception are Robert Freitas medical nanorobots like e.g. his respirocyte.
    Also J.Storrs Halls utility foglets. (Those are still rather general though.)

    What people probably most often think when they hear the common terms for nanorobots though are "molecular assemblers" but those are by now considered:

    • impractical (inefficient and harder to reach than nanofactories)
    • undesirable (because of real forms of grey goo - less crazy than the SciFi depictions but still bad)
    • but not fundamentally impossible (advanced nanofactories should be programmable to build them)

    These opinion is now held from all the core experts including E.Drexler & Co    
    1992...2015 => molecular assemblers are by now 22 years out of date
    Robert Freitas too - as you can hear in this video:

    There are several other types of more or less autonomous and more or less freely movable nano-robotic devices:

    • elasticity emulating microcomponents (specialised weaker form of utility foglets)
    • microcomponent maintenance devices for low throughput maintenance purposes in products. While the products are actively running they could e.g. exchange radiation damaged parts and keep the products (e.g. motor material inside infrastructure) functional for arbitrary long spans of time. In contrast to molecular assemblers they would be incapable of self replication or mechanosynthesis.
    • lots and lots of further ones ...

    Nanorobots are only a small side dish to the so much overlooked diamondoid metamaterials though.
    Those are the real basis for the gro of advanced diamondoid APT products.
    I'am collecting my findings about diamondoid metamaterials here:…e=Diamondoid_metamaterial

    Request for forum "folders":

    • 1 APM specific basics (Basics)
    • 2 far term productive nanosystems (Far Goal)
    • 3 far term products (Applications)
    • 4 near term path (Path)
    • 5 speculative economical and ecological consequences (Impacts)
    • 6 off-topic misc (Misc)

    Currently the folder "Impacts and Applications" mixes up two of them.

    I guess threads can't be relocated in retrospect (by admin / thread starter) - can they?

    Request for forum "folders":

    • APM specific basics (Basics)
    • far term productive nanosystems (Far Goal)
    • far term products (Applications)
    • near term path (Path)
    • speculative economical and ecological consequences (Impacts)
    • off-topic misc (Misc)

    Currently the folder "Impacts and Applications" mixes up two of them.

    Due to it's importance I've moved this comment to its own thread:

    Related to this quite some time ago I extracted this flow-chart out of the minimal toolset paper:

    In the diagram above this chart corresponds to the points:

    • moiety preparation
    • moiety routing
    • tooltip cycle

    This is only the most minimal toolset. You can begin to see the complexity here.
    The red ones are rate limiting gas pase steps which still need better solutions.
    Note that I had to decide for a lot of tradeoffs in this visualisation.
    It is thus far from perfect and definitely improvable.
    (License: Public Domain)

    Attached files yEd-tooltip-cycle-graph_v1.00.graphml (297.3 KB)

    Some thoughts:

    • Is it easy to make make backups with this forum SW?
    • Since this seems to be not a mainstream forum software migrating might become difficult in the future.
    • With AI cracking captchas spam protection becomes a nightmare - my website was attacked pretty soon - worry ...
    • (Where do you host it?)
    • I've contacted ~30 people (austria) which might be interested checking out this forum.
    • ... I might PM you about the last point sometime but not now ...


    • I realized that the search function could be made less stringent. I quickly ran in a 30sec timeout.
    • The list on the left is hard to read - lack of spaces makes it difficult to see whether its just a second line or the next topic.
    • the quoting button doesn't always work
    • (are sticky notes possible?)
    Quote from Lukas (LSUESS)

    Then there's the point that a static target (e.g. a chemically bond hydrogen atom) is totally unsuitable:
    See what I noted in the comments of this video (~ 6 months ago - citation omitted)
    >> Here Ralph merkle sidemotes: "... atoms have nuclei which are point-masses and yeah they blur a little bit but who cares forget about it ..."
    While irrelevant for APM - if we attempts "shoot-and-hit-fusion" we do care.
    I do repeatedly get the classic question why those nano-machines don't quantum disperse and get useless. That's a reason for this comment.

    Just for completeness in case that youtube comment vanishes in the future:

    Quote from Lukas (LSUESS)

    aka mechadense

    20:30 About quantum blurryness - another take on this is: If you capture a molecule in a tight space (e.g. in a box) you do work against degeneracy pressure which is released in "omnidirectional" kinetic energy when you suddenly lift its spacial constraints completely. The thighter it was compressed in space the faster it's probability distribution will fall apart. This is heisenbergs uncertainty principle in slightly unconventional wording. (small spacial distribution -> wide impulse distribution -> fast wave packet dispersion) Judging from this macroscopic crystals which's average outer positions can (it has been done) be measured down to the femtometer level in space should fall apart instantly because of this extreme sharpness in space. But they don't! Why is an interesting question on itself - it has todo with not yet well understood quantum decoherence. If you strongly bond a small molecule to the crystal (that is you use the crystal as a movement constraining box) the molecule essentially becomes part of the crystal and inherits its sharp and not apart-running position. Actually the macroscopic position of the crystals roughly pins down the positions of the atomic nuclei of the molecule. The exact positions of the nuclei (at 0K temperature) can't be determined as exact as the position of a macroscopic crystal though. The actual size of the probability distribution cloud for a nucleus is maintained through the "chemical bond force box" the size of this cloud is below the size of its host atom but above the size of the nucleus. As a sidenote the size of the nucleus is maintained through its "nuclear force box" and the size of a whole atom (electron shell) is maintained through the "electrostatic core potential box". To theoretically recreate the actual "force-pictures" that have been taken of molecules you have to "add" to the core crystal location that does not run apart the nucleus blurryness, the electron shell blurrieness and finally some thermal blurrieness - the same for the opposing needle tip. (actually mathematically this "adding" is folding)

    I think we have a case of "separation of concerns" here:
    A.) phase space volume (PSV) compression
    B.) acceleration
    C.) focussing
    Keeping those apart should make solving them easier.
    I think combining any of these should only be done if a compelling reason is found.
    It seems to make sense to do it in the order A-B-C.

    Regarding A.) PSV compression

    I'm not entirely clear what you where trying to simulate.
    I guess the evolution/propagation of the wave function of one single proton.
    A simple simulation assumes perfect knowledge over the wave function - pure state (is that correct?)
    Thus no matter how you choose your wave function it always has the minimal phase space volume (hbar).
    Then when assuming a certain initial spacial localisation the packet won't spread faster than the minimum speed.

    In reality though you have limited knowledge over the wave function and thus you have a PSV which is bigger than hbar even for a single particle. Thus I guess you have to do a more complex simulation over an ensemble of possible wave-functions. (Is that the right way to simulate the lack of knowledge over the wave function?)
    In other words additionally to the quantum blurriness some knowledge uncertainty adds to it: (Density operator)
    I wonder: Is this operator normally only applied to bunches of particles?
    Annealing e.g. will only work with more than one particle.
    So I’m not really sure how to compress PSV here.

    Regarding B.) acceleration

    While accelerators which are sufficient to boost ions to fusion energies can be relative small** (m scale) in relation to particle accelerators (km scale) I think they'll always remain big relative to the nano-scale.
    [** Neutral Beam Injection for ITER >900tons! - whopping 1000keV though]

    The most compact way to accelerate ions with APT that I currently know of are optical cavity accelerators:…accelerator-built-on.html
    Interesting video:
    Basically analogue to these microwave accelerators just finer but still with similar total length.…e:Desy_tesla_cavity01.jpg
    Trouble: the small channel (dx) => big dp in transversal directions :S => B-A-C ??

    Side-note: The energy barriers for fusion are not hard to calculate but I just found that tables for them are somewhat missing on the net. Wikipedia: "... ignition temperature is about 4 keV for the D-T reaction and about 35 keV for the D-D reaction."

    Regarding C.)

    That's the only part of the three (A,B,C) you actually seem to have simulated.
    You seem to do make a choice of some arbitrary initial localisation resulting in an corresponding equally arbitrary (but corresponding) dispersion speed. (Choosing e.g. the size of the proton in its nuclear force "box" 1.7e-15m makes no sense - that should be obvious though.) The only size that I see that’s special here is the radius of the acceleration ring. Widest starting slowest dispersion. (?? output size of an acceleration channel ??)

    >> JimL: "The system isn't closed because, classically at least, a charged particle moving through the focussing fields will experience acceleration and thus radiate energy away. If it weren't for quantum mechanics the nuclei would most likely first settle into an ever tighter beam line and then eventually slow to a stop, since there are field potentials along every axis."

    I'm not entirely sure I get what you're trying to say here.

    While you can increase or decrease a particles energy with external electric or magnetic fields I'm not sure it is possible to make its energy more precise - that is lowering its entropy or in an uncommon formulation quasi cooling it at a hot temperature - (A&C intermixed - bad?). With electromagnetic fields this is surely possible as laser-cooling shows.
    It might have to do with that:
    a.) magnetic fields preserve energy (except synchrotron radiation at high energies)
    b.) electric fields preserve (... what was it again? - darn I forgot).
    (Side-note: I think this is applied to visualize local spots of the table of nucleotides with a Wien filter.)

    ps: The necessary massive parallelism and high frequency for a practical level of power generation will make this endeavour even more difficult.

    Ah APT and nuclear fusion - an interesting topic!
    Btw: (offtopic) Wendelstein 7-X is starting soon :)

    >> JimL: "... realized I was about to embark on an original research project that would take a long time. ..."
    Yep it's completely uncharted area there.

    >> JimL: "... So first thing I felt I had to do was write some simulation code ... That was a mistake - at least if I had planned to complete the article in any reasonable time frame. ..."
    You indeed picked one of the most difficult topics there are - regarding applications of advanced APM products.

    I’m not sure if it is even in principle possible to archive "shoot and hit" fusion. What I mean with this just invented term is a fusion of a pair* of nuclei with a probability >>50% to archive a successful hit on the first try. (I assume this is what you where trying to investigate here.) I see no possibility for exploratory engineering here - too many missing reliable models.

    IIRC I once heard something along the lines that: "one cannot focus a particle beam (in position space) below what it was at the point of origin because of Liouville's theorem of constant phase space volume (of closed systems?)"**'s_theorem_%28Hamiltonian%29
    I once came in contact with people working on shooting highly charged ions through fine channels.
    I think someone of them said that this could maybe cheat this unfocussability limitation.
    (I doubt this is applicable here.)

    I think aforementioned limitation** is a oversimplification though - since laser-cooling & something like evaporation cooling can AFAIK compress phase space in free(?) position space. There seem to be further methods as a quick search just now revealed: See "Conservation of emittance" - this may be related:…Conservation_of_emittance

    It certainly won't hurt to have the minimal possible volume in phase space (that is planks volume hbar) at the release point from machine phase to free flight.

    Then there is the point that the starting impulse must be incredibly accurate such that you actually accurately hit the target. This equates to compactness in impulse space and consequently wide dispersion in position space.

    The result: nano-scale focussing wont work since you have to start with micro to macro-scale wave functions. You have to start with a super-cool and spatially widely de-localized proton/deuteron/.. and accelerate its whole wave-function in an incredibly noise free way to get it cold and hot at the same time (in different directions - spherically symmetric??).

    It may help simulate the process in reverse (backward in time) to find out what you need to start with.
    The goal situation seems relatively simple: plank constant & target nucleus size -> projectiles minimal necessary impulse uncertainty at the focus ... (don't forget coulomb repulsion + small errors)

    An interesting question regarding this that I found is: Could supercooled ion trap boxes of a size of some microns to centimetres be used to transport only a part of the wave function of an ion? Some method of transport with even lower friction than super-lubrication may be necessary. I'm collecting my thoughts about such levitation/hyper-lubrication here:

    If a "shoot-and-hit-fusion" attempt is really successful I see no chance in hell that you'll be able to control the exit trajectory. Catching high entropy exit particles without messing up the super-cool environment seems very difficult. If you're that good at things you may start to think about efficiently producing antimatter - which I today consider 100% Si-Fi.

    Depending on the choice of fusion partners you may need a third partner to receive the released energy in form of impulse and prevent purely radiative energy release (which seems hardest to capture)

    Then there's the point that a static target (e.g. a chemically bond hydrogen atom) is totally unsuitable:
    See what I noted in the comments of this video (~ 6 months ago - citation omitted)
    >> Here Ralph merkle sidemotes: "... atoms have nuclei which are point-masses and yeah they blur a little bit but who cares forget about it ..."
    While irrelevant for APM - if we attempts "shoot-and-hit-fusion" we do care.
    I do repeatedly get the classic question why those nano-machines don't quantum disperse and get useless.
    That's a reason for this comment.

    An interesting question related to "shoot-and-hit-fusion" that should also be useful for other things is how to best ionize atoms (e.g. hydrogen) and contain those ions in an advanced APT system.

    All in all I think putting a lot of effort into "shoot-and-hit-fusion" isn't helping speed up development of APM.
    It is super complex and seems far off and thus pulls too much on the suspense of disbelieve. Thus its not on my personal priority list.


    Beside the yet very speculative "shoot-and-hit-fusion" there will be much more unspeculative possibilities to use APM to boost conventional fusion approaches.
    I'm collecting my thoughts about this here - only a bulleted list yet:

    I think inertial fusion could be made much more compact (no idea how much exactly) and could go easily beyond break-even. Crashing nuclei with their electron hull makes things much more complicated on the simulation side.
    I'd expect severe limits on the downscalbility because of physical scaling laws though.

    Ater some back on the envelope calculations. I think that stellerator style fusion won't get light enough for e.g. a mobile spaceship (where fusion makes IMO most sense) even with usage of APT materials.


    >> JimL: "What annoys me the most, though, is ... I can't find my old C and Python code ..."

    I too have lost something APM related once. It was the newest version of this poor little fella:
    Particularly I've lost the work I've done to fit it inside itself in its collapsed state.
    I made this model when I still didn't know the shortcomings of the molecular assembler concept.


    some remotely related links: --- interesting image

    Attached files

    >> ... I found very few [videos] of any educational value. ...

    What is certainly and especially missing are videos along the lines of what E.Drexler does in his new book "Radical Abundance"
    # Chapter 5 "The Look and Feel of the Nanoscale World"
    # Chapter 10 "The Machinery of Radical Abundance"
    I plan to tackle that and more (with as much graphics as possible) in the "basics" and "tour through nanofactory" sections I mentioned. The missing videos in this area are the reason why I wrote:
    >> me: "... I want to present for the first time the already existing knowledge of nano-factories in a well illustrated way that ..." and why I want to make these videos in the first place.

    For the topic "products of nanofactories" there are some videos out there but not much:
    I especially like J. Storrs Hall "whether machine"-video ...
    ... because he focusses on the more overlooked side of applications that I'm especially interested in.
    It's imo one of the more speculative applications though.
    Btw: I'm collecting APM related topics that I think are unjustifiably under-represented here:

    >> ... The closest I thought that came to having useful material of use to scientists, engineers, and technologically literate audience is this one by Ralph Merkle: ...

    As chance has it I re-watched this one just a few days ago since its the first link on R.Merkles homepage.
    (details off-topic -> omitted)

    >> ... I did review several hundred, sorted first by view count, then by viewer ratings, and lastly by most recently uploaded. ...

    Wow, quite a bit of effort ...

    If it comes to general introductory videos there are quite a view out there. I'm collecting the best introductory videos I occasionally find at the bottom of my wikis mainpage. See here:…Manufacturing_Wiki#Videos
    (I've never checked the view-counts though - viewer rating may be not too important if the views are plenty?)

    Are there any you have missed in there?

    There are more in depth videos about APM related topics but they are mostly too technical for the general audience like:
    The foresight conference videos (mostly near term topics) of which I found some rather interesting:
    This video about mechanosynthesis is really great but also not suitable for the general audience:

    >> A couple months ago I did search Youtube for videos where the word "nanotechnology" ...

    Have you read Drexlers "five types of nanotechnology" blog entry?…-kinds-of-nanotechnology/
    Basically the term "nanotechnology" is as specific as "makrotechnology" thus its no surprise that it got annexed.

    Out of this reason I also consider using the term "minifactory" instead of "nanofactory" relating to the size of the whole thing and not the size of its smallest components.
    Good Idea / Bad Idea?
    (I ditched personal factory, personal fabricator, living room factory)

    Choosing sensible nomenclature is a difficult task. I note my ideas about that topic here:
    (It seems I need to reread "Radical Abundance" to find out whether Drexler refers with APM to the whole path or more to far term goal)

    Btw: I came up with the term Gemstome-Gum-*** or Gem-Gum-***
    *** = [Technology|Factory|Manufacturing|...]
    I think it fulfils the major requirements:
    1.) it is catchy (probable to be actually used)
    2.) it is accurate enough to be unannexable (the term provides a concrete example for a diamondoid meta-material - out of which nanofactories ad their products are mostly made)

    Your thoughts?

    In general I've mostly stopped using anything with the "nano" prefix for internet searches.
    When skimming for videos I often search for the names of the main persons in the realm of APM and filter for the newest material.
    In general now when I'm starting a conversation about APM I usually take the route over "advanced production technologies" starting with 3D printing and avoiding nano prefix altogether - it helps - the conversation does not immediately deteriorate into the sunscreen, lotus-spray or a similar direction.