View source for Rising surface area per volume of smaller machinery parts

A well known [[scaling law]] with some availability bias of over other [[lesser known scaling laws]] <br>
that need to be looked at too to get the full picture.

== Consequences & counters ==

★ '''Higher surface available for chemical reactions'''; higher catalytic activity; see page: [[Oxidation]] countered by <br>
– [[sealing of the sensitive interior]] (fruit interior analogy) & <br>
– picking the right non-reactive stiff for the exterior e.g. by H of F passivated diamond (see: [[Atomically precise surface passivation]]) <br>

★ '''[[Higher bearing surface area of smaller machinery]]''' countered by <br>
– [[higher throughput of smaller machinery]] and <br>
– the paradoxically seeming approach of [[Increasing bearing area to decrease friction]] <br>

★ '''[[Less effective thermal insulation of smaller machinery]]''' <br>
– Don't do mechanosynthesis in free floating nanobots. This is a bad idea for many other reasons not only including safety. <br>

★ '''[[More difficult cooling of bigger machinery]]''' (equivalently to the preceding just the flipped viewpoint) <br>
– Be aware of [[limits of power density imposed by limits of cooling]], <br>
… the absurdly high seeming values for [[power density]] stated in the book [[Nanosystems]] <br>
… do not take cooling into account (so meant but not well and clear stated). <br>
… These values do only hold for systems so small that they are still steady state coolable <br>
… exclusive or short bursts in bulk where the thermal capacity can take the waste heat without thermal damage. <br>

== This scaling law as major source of criticism towards proposed [[macroscale style machinery at the nanoscale]] ==

This well known scaling law and its consequences is one of the most predictably upcoming <br>
criticisms towards the idea of [[macroscale style machinery at the nanoscale]]. <br>
But the here mentioned counters are rarely seen as these come from … <br>
★ [[lesser known scaling laws]] <br>
★ assumptions based on current day experimental capability limits <br>
– e.g. limited sealing against rest gasses in UHV, <br>
– [[FAPP]] perfect vacuum [[PPV]] not yet achievable due to chamber volume smallness and sealing quality and surface quality limits) <br>

== Related ==

* [[Bigger surface area of smaller machinery]] … more redundant page
* [[Twice the surface area of half the volume]] … somewhat redundant page
* [[Scaling laws]]
* [[Macroscale style machinery at the nanoscale]]
* [[Oxidation]]
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* [[Common critique towards diamondoid atomically precise manufacturing and technology]]

== External links ==

* [https://en.wikipedia.org/wiki/Square%E2%80%93cube_law Square–cube law]
* [https://en.wikipedia.org/wiki/Allometry Allometry] – (related: [https://en.wikipedia.org/wiki/Tree_allometry Tree allometry])
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* [https://en.wikipedia.org/wiki/Surface-area-to-volume_ratio Surface-area-to-volume ratio] – (related: [https://en.wikipedia.org/wiki/Allen%27s_rule Allen's_rule])
* [https://en.wikipedia.org/wiki/Kleiber%27s_law Kleiber's law] – metabolic rate of animals over mass – (related: [https://en.wikipedia.org/wiki/Metabolic_theory_of_ecology Metabolic theory of ecology])