Difference between revisions of "Stiffness"

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{{stub}}
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  the less soft the nanomachinery the less imprecise the mechanosynthesis
  
−
Gradually introducing sufficient stiffness into atomically precise structures
+
Sufficient stiffness (more precisely: [[lattice scaled stiffness]]) is necessary …
−
is of key importance for [[bootstrapping]] the far term goal of advanced [[nanofactories]] through a series of earlier increasingly more powerful atomically precise [[productive nanosystems]].
+
* … for sufficient suppression of thermal vibration amplitudes.
 +
* … to archive [[atomically precise positioning]] capability not just [[topological atomic precision]]
 +
* … for making force applying [[mechanosynthesis]] possible
 +
Also sufficient stiffness is …
 +
* one reason for the choice of [[gemstone like compound]]s as good base material / far term target material
 +
* an enabler for [[machine phase]] as a basis/enabler for fuhrer capabilities like …
 +
* … [[dissipation sharing]] (an/the efficiency trick that soft molecular biology nanotechnology can't pull) and …
 +
* … [[exothermy offloading]] (same)
  
−
Sufficient stiffness is:
+
== Pathway perspectives ==
−
* necessary for sufficient suppression of thermal vibration amplitudes. <br> First sufficiently below the size of pre-produced atomically precise blocks and self-alignment/self-centering slots. <br>Later sufficiently below atom to atom distance to exponentially suppress misplacement errors.
+
−
* necessary to archive [[atomic resolution]] not just [[atomic precision]]
+
−
* necessary for making force applying [[mechanosynthesis]] possible
+
−
* one reason for the choice of [[diamondoid compounds]] as good base material / far term target material
+
  
−
== Sufficient lattice scaled stiffness for early low stiffness systems ==
+
'''[[Direct path]] perspective:''' <br>
 +
Already starting out with high stiffness. <br>
 +
There are only some (but not none) stiffness challenges in the beginning. <br>
 +
The main challenge is rather becomes scaling up the essential system complexity many orders of magnitude. <br>
 +
See: [[Early diamondoid nanosystem pixel (direct path)]]
  
−
Usage of self assembled [[atomic precision|atomically precise]] base parts (aka "vitamins") allow for less stringent conditions on stiffness.
+
'''[[Incremental path]] perspective:''' <br>
−
Only the '''lattice scaled stiffness''' must be sufficient for block based self centering assembly (which is not really callable "mechanosynthesis" yet).
+
Gradually introducing sufficient stiffness into atomically precise structures <br>
 +
is of key importance for [[bootstrapping]] the far term goal of advanced [[nanofactories]] <br>
 +
through a series of earlier increasingly more powerful atomically precise [[productive nanosystems]].
  
−
{{todo|Add external link to lattice scaled stiffness explanation page.}}
+
Amplitudes of thermally excited motions:
 +
* First sufficiently below the size of pre-produced atomically precise blocks and self-alignment/self-centering slots.
 +
* Later sufficiently below atom to atom distance to exponentially suppress misplacement errors.
 +
 
 +
== Stiffness & mechanosynthesis ==
 +
 
 +
Two approaches to reduce misplacement error rates in [[mechanosynthesis]]:
 +
* '''Higher stiffness''' of the structures for placement ([[kinematic loop]], structure near tip apex) <br>=> exponential drop in error rates
 +
* '''[[Cooling]] locally''' the site of mechanosynthesis <br> => linear drop in error rates, then nonlinear - eventual quantum freezout of phonon modes even <br>Related: Averting locally exoergic/exothermic reactions (this may not be that much of an issue, TBD)
 +
 
 +
=== Sufficient lattice scaled stiffness for early low stiffness systems ===
 +
 
 +
Usage of self assembled [[topological atomic precision|atomically precise]] base parts (aka "vitamins") allow for less stringent conditions on stiffness. <br>
 +
Only the '''[[lattice scaled stiffness]]''' must be sufficient for block based self centering assembly (which is not really callable "mechanosynthesis" yet).
 +
 
 +
{{wikitodo|Add external link to lattice scaled stiffness explanation page - Eric Drexlers blog on internet archive.}}
 +
 
 +
There's also: [[stiffness focusing]] / [[foldamer technology stiffness nesting]]
  
 
== How stiffness scales with size ==
 
== How stiffness scales with size ==
  
−
The [[scaling law]] for stiffness is such that smaller structures have lower stiffness ("softer"). {{todo|Add math and graph.}} Nanoscale diamond e.g. has a compliance that when interpreted at the macroscale lies in a very intuitively understandable range.
+
The [[scaling law]] for stiffness is such that smaller structures have lower stiffness ("softer"). <br>
 +
See (with a '''big caveat below'''): [[Lower stiffness of smaller machinery]] <br>
  
−
== Influence on manipulator design ==
+
'''There's [[a better intuition for diamondoid nanomachinery than jelly]]!''' <br>
  
−
The choice of geometric design of nano-manipulators must be taken such that the compliance of the material is compensated for. Long skinny serial mechanics robotic arms (like many industry robots on the macroscale) are a bad choice for the deep nanoscale. Bulky parallel mechanic manipulators are a good choice.
+
Big caveat: This is actually quite misleading. What mostly matters instead is that <br>
 +
deflections from scale natural nanomachine motion frequencies <br>
 +
(assuming scale invariant constant speeds) stay the same. <br>
 +
See: [[Same relative deflections across scales]] <br>
 +
Or even drop with a bit due to some intentional slowdown for speeds at the nanoscale <br>
 +
Slowdown in speeds being compensated by [[higher throughput of smaller machinery]]! <br>
 +
Intentional slowdown to reduce (wearless) dynamic friction losses. <br>
 +
 
 +
Trivia: Weird coincidence from [[Lower stiffness of smaller machinery]]: <br>
 +
Nanoscale diamond e.g. has a compliance that, when interpreted at the macroscale, <br>
 +
lies in a very intuitively understandable range. <br>
 +
See: [[The feel of atoms#Softness]] <br>
 +
 
 +
== Influence of stiffness on manipulator design ==
 +
 
 +
The choice of geometric design of nano-manipulators must be taken such <br>
 +
that the compliance of the material is compensated for. <br>
 +
Long skinny serial mechanics robotic arms (like many industry robots on the macroscale) <br>
 +
are a bad choice for the deep nanoscale. These will increase error rates in [[mechanosynthesis]]. <br>
 +
Bulky parallel mechanic manipulators are a good choice. <br>
 +
 
 +
In advanced [[gem-gum factories]] this may be mostly an issue for <br>
 +
structures in [[building chamber]]s doing [[mechanosynthesis]]. <br>
 +
I.e. mostly the very many highly specialized [[molecular mills]] in [[assembly level 1]]. <br>
 +
And some very few (much slower and much more inefficient) special general purpose post processing stations. <br>
 +
 
 +
Note: Low temperatures (deep cryo) can help as a complementary factor. <br>
 +
I.e for low temperatures and decently stiff base structures <br>
 +
(excliding e.g. 3D structural DNA nanotechnology, including [[cryctolecule]] based stsructures) <br>
 +
somewhat filigree structures may work even at deep nanoscale. <br>
 +
 
 +
== Influence of stiffness on friction ==
 +
 
 +
More stiffness causes less or harder to excite degrees of freedom for thermal motion.<br>
 +
This allow for lower levels of friction.<br>
 +
See: [[Friction in gem-gum technology]] <br>
 +
 
 +
Also to a particularly lack of stiffness related dissipation mechanism to investigate: [[Accidental heatpump]]
 +
 
 +
== The limit to zero stiffness in early [[incremental path]] aka [[foldamer]] systems ==
 +
 
 +
Unfolded foldamers basically have zero stiffness (or rather the concept of stiffness breaks down) due to <br>
 +
their chains of single bonds allowing for quite unconstrained freedom of rotation.
 +
 
 +
They can attain stiffness when they fold up though by formation of internal bonds like <br>
 +
hydrogen bonds, dative bonds, [[Van der Waals force|Van der Waals bonds]], and sometimes even covalent crosslinking bonds. <br>
 +
Some for this property optimized [[de-novo proteins]] can attain quite significant stiffness.
 +
 
 +
[[Structural DNA nanotechnology]] is an interesting case.
 +
Even after assembly locally there is practically zero stiffness.
 +
On a larger scale there is stiffness albeit quite low one.
 +
 
 +
Consequences of this include:
 +
* [[Structural DNA nanotechnology]] features [[topological atomic precision]] but no [[positional atomic precision]].
 +
* [[Structural DNA nanotechnology]] can on it's own position something to [[positional atomic precision]] only over a time average.
 +
* [[Structural DNA nanotechnology]] may be able to position something to [[positional atomic precision]] …<br> via [[Foldamer technology stiffness nesting]]/[[stiffness focusing]] i.e. <br>via integration of stiffer structural nanotechnologies
  
 
== General ==
 
== General ==
  
−
The SI unit of stiffness is newtons per square meter (N/m<sup>2</sup>) <br>
+
* The SI unit of (material specific) stiffness is newtons per square meter (N/m<sup>2</sup> = Pa) (Young modulus tensor)<br>
−
The inverse of stiffness is called compliance. Not softness which would be the inverse of hardness.
+
* The inverse of stiffness is called compliance. Not softness which would be the inverse of hardness.
 +
* Unit of simple geometry specific stiffness is N/m (Hooks law applies)
 +
 
 +
== Related ==
 +
 
 +
* '''[[The defining traits of gem-gum-tec]]'''
 +
* [[Macroscale style machinery at the nanoscale]]
 +
* [[Lattice scaled stiffness]]
 +
* [[Mechanosynthesis]]
 +
* [[Gemstone like compound]]
 +
* [[High pressure]]
 +
* '''[[Energy, force, and stiffness]]'''
 +
* [[Lower stiffness of smaller machinery]] – a [[scaling law]]
 +
* '''[[Same relative deflections across scales]]'''
 +
* [[Sloppy finger problem]]
 +
----
 +
* '''[[Stiffness focusing]]''' and '''[[Foldamer technology stiffness nesting]]'''
 +
----
 +
* [[Characteristic bending length]]
 +
* [[Spiroligomers]]
 +
* [[Highly polycyclic small molecule]]
 +
 
 +
== External links ==
 +
 
 +
Related pages from <br>Eric Drexler's blog: '''Metamodern''' – The Trajectory of Technology <br>
 +
Recovered with the internet archives wayback machine. <br>
 +
<small>(More recovered pages from this blog can be found here: [[Eric Drexler's blog partially dug up from the Internet Archive]])</small>
 +
 
 +
* Blogpost 2009-02-20: [https://web.archive.org/web/20160331095526/http://metamodern.com/2009/02/20/nanomaterials-for-nanomachines/] <br>"Nanomachines, Nanomaterials, and K<sub>lm</sub>" <br>Subtitle: "Toward Advanced Nanotechnology: Nanomaterials (5)"
 +
* Blogpost 2009-02-15:  [https://web.archive.org/web/20160327213120/http://metamodern.com/2009/02/15/nanomaterials-nanostructures-and-stiffness/]. <br>"Nanostructures, Nanomaterials, and Lattice-Scaled Stiffness"<br> Subtitle: "Toward Advanced Nanotechnology: Nanomaterials (4)" <br>(Note: the uncrecovered direct link [http://metamodern.com/2009/02/15/nanomaterials-nanostructures-and-stiffness/] works for this specific post '''BUT'''<br> many internal links are broken. Database damage presumably?)
 +
 
 +
=== Wikipedia ===
 +
 
 +
* [https://en.wikipedia.org/wiki/Persistence_length Persistence length] – See: [[Characteristic bending length]]
 +
----
 +
* [https://en.wikipedia.org/wiki/Stiffness Stiffness]
 +
* [https://en.wikipedia.org/wiki/Hooke%27s_law Hook's law]
 +
* [https://en.wikipedia.org/wiki/Young's_modulus Young's modulus]]
 +
----
 +
Some of the German pages seem better as of 2022:
 +
* Stiffness – [https://de.wikipedia.org/wiki/Steifigkeit Steifigkeit]
 +
* Spring constant – [https://de.wikipedia.org/wiki/Federkonstante Federkonstante]
 +
* Elastic modulus – [https://de.wikipedia.org/wiki/Elastizit%C3%A4tsmodul Elastizitätsmodul]

Latest revision as of 11:23, 10 January 2025

 the less soft the nanomachinery the less imprecise the mechanosynthesis

Sufficient stiffness (more precisely: lattice scaled stiffness) is necessary …

Also sufficient stiffness is …

Pathway perspectives

Direct path perspective:
Already starting out with high stiffness.
There are only some (but not none) stiffness challenges in the beginning.
The main challenge is rather becomes scaling up the essential system complexity many orders of magnitude.
See: Early diamondoid nanosystem pixel (direct path)

Incremental path perspective:
Gradually introducing sufficient stiffness into atomically precise structures
is of key importance for bootstrapping the far term goal of advanced nanofactories
through a series of earlier increasingly more powerful atomically precise productive nanosystems.

Amplitudes of thermally excited motions:

  • First sufficiently below the size of pre-produced atomically precise blocks and self-alignment/self-centering slots.
  • Later sufficiently below atom to atom distance to exponentially suppress misplacement errors.

Stiffness & mechanosynthesis

Two approaches to reduce misplacement error rates in mechanosynthesis:

  • Higher stiffness of the structures for placement (kinematic loop, structure near tip apex)
    => exponential drop in error rates
  • Cooling locally the site of mechanosynthesis
    => linear drop in error rates, then nonlinear - eventual quantum freezout of phonon modes even
    Related: Averting locally exoergic/exothermic reactions (this may not be that much of an issue, TBD)

Sufficient lattice scaled stiffness for early low stiffness systems

Usage of self assembled atomically precise base parts (aka "vitamins") allow for less stringent conditions on stiffness.
Only the lattice scaled stiffness must be sufficient for block based self centering assembly (which is not really callable "mechanosynthesis" yet).

(wiki-TODO: Add external link to lattice scaled stiffness explanation page - Eric Drexlers blog on internet archive.)

There's also: stiffness focusing / foldamer technology stiffness nesting

How stiffness scales with size

The scaling law for stiffness is such that smaller structures have lower stiffness ("softer").
See (with a big caveat below): Lower stiffness of smaller machinery

There's a better intuition for diamondoid nanomachinery than jelly!

Big caveat: This is actually quite misleading. What mostly matters instead is that
deflections from scale natural nanomachine motion frequencies
(assuming scale invariant constant speeds) stay the same.
See: Same relative deflections across scales
Or even drop with a bit due to some intentional slowdown for speeds at the nanoscale
Slowdown in speeds being compensated by higher throughput of smaller machinery!
Intentional slowdown to reduce (wearless) dynamic friction losses.

Trivia: Weird coincidence from Lower stiffness of smaller machinery:
Nanoscale diamond e.g. has a compliance that, when interpreted at the macroscale,
lies in a very intuitively understandable range.
See: The feel of atoms#Softness

Influence of stiffness on manipulator design

The choice of geometric design of nano-manipulators must be taken such
that the compliance of the material is compensated for.
Long skinny serial mechanics robotic arms (like many industry robots on the macroscale)
are a bad choice for the deep nanoscale. These will increase error rates in mechanosynthesis.
Bulky parallel mechanic manipulators are a good choice.

In advanced gem-gum factories this may be mostly an issue for
structures in building chambers doing mechanosynthesis.
I.e. mostly the very many highly specialized molecular mills in assembly level 1.
And some very few (much slower and much more inefficient) special general purpose post processing stations.

Note: Low temperatures (deep cryo) can help as a complementary factor.
I.e for low temperatures and decently stiff base structures
(excliding e.g. 3D structural DNA nanotechnology, including cryctolecule based stsructures)
somewhat filigree structures may work even at deep nanoscale.

Influence of stiffness on friction

More stiffness causes less or harder to excite degrees of freedom for thermal motion.
This allow for lower levels of friction.
See: Friction in gem-gum technology

Also to a particularly lack of stiffness related dissipation mechanism to investigate: Accidental heatpump

The limit to zero stiffness in early incremental path aka foldamer systems

Unfolded foldamers basically have zero stiffness (or rather the concept of stiffness breaks down) due to
their chains of single bonds allowing for quite unconstrained freedom of rotation.

They can attain stiffness when they fold up though by formation of internal bonds like
hydrogen bonds, dative bonds, Van der Waals bonds, and sometimes even covalent crosslinking bonds.
Some for this property optimized de-novo proteins can attain quite significant stiffness.

Structural DNA nanotechnology is an interesting case. Even after assembly locally there is practically zero stiffness. On a larger scale there is stiffness albeit quite low one.

Consequences of this include:

General

  • The SI unit of (material specific) stiffness is newtons per square meter (N/m2 = Pa) (Young modulus tensor)
  • The inverse of stiffness is called compliance. Not softness which would be the inverse of hardness.
  • Unit of simple geometry specific stiffness is N/m (Hooks law applies)

Related

External links

Related pages from
Eric Drexler's blog: Metamodern – The Trajectory of Technology
Recovered with the internet archives wayback machine.
(More recovered pages from this blog can be found here: Eric Drexler's blog partially dug up from the Internet Archive)

  • Blogpost 2009-02-20: [1]
    "Nanomachines, Nanomaterials, and Klm"
    Subtitle: "Toward Advanced Nanotechnology: Nanomaterials (5)"
  • Blogpost 2009-02-15: [2].
    "Nanostructures, Nanomaterials, and Lattice-Scaled Stiffness"
    Subtitle: "Toward Advanced Nanotechnology: Nanomaterials (4)"
    (Note: the uncrecovered direct link [3] works for this specific post BUT
    many internal links are broken. Database damage presumably?)

Wikipedia

Some of the German pages seem better as of 2022:

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