Difference between revisions of "Consistent design for external limiting factors"

Revision as of 10:27, 20 May 2014

When designing a product usually one wishes that it poses some resilience to environmental influences. A few critical delicate components in a mainly robust system can bog down the whole system. Those components are the weakest links in the chain and constitute some kind of bottleneck. To avoid disproportionate bog-down components should be paired with their resilience ranges, that is microcomponents could be tagged with links to informations on allowed ranges. This way one can design a system consistently for a chosen set of external limiting factors that one requires. or maximize certain limiting factors.

External limiting factors can be:
temperature T, radiation I , .., acceleration a, pressure p, ...

absolute maximum/minimum Temperature

The allowed temperature range of a whole system (on a thermally equilibrated micro-scale) is defined by the intersection of all the allowed temperature ranges of the system components. When using technology of brownian technology path in e.g. technology level III either in the process of reaching it or when re-merging after reaching it the machine phase (e.g. entropic batteries) AP Technology will acquire an accordingly restricted range of allowed operation temperature range especially much of the otherwise down to zero kelvin completely allowed low temperature regime will be cut off.

It is advisable to keep track off all the allowed temperature ranges for system components (no matter which technology path) and keep the technology path branches (with vastly different allowed temperature ranges) as separate as possible.

Diamond is metastable and can turn into graphite at too high temperatures. Other diamondoid materials like the carbides of the titanium vanadium and chromium group (interstitial carbides) can be used for high temperature applications since they are refractory. (complete sets of DMEs are needed). Stability of free or mutual or environmentally contacting passivated surfaces (that are possibly strained) will reduce the allowed temperatures well below the bulk material melting points though. Interstitial diffusion may too be a limiting factor.

4th period:

• TiC (3,160 °C; 5,720 °F; 3,430 K; abundant elements)
• VC (2810 °C; 9-9.5 Mohs)
• Cr₃C₂; Cr₇C₃; Cr₂₃C₆ (1,895 °C; 3,443 °F; 2,168 K; extremely hard; very corrosion resistant)

5th period:

• ZrC (3532 °C; extremely hard; highly corrosion resistant; very metallic)
• Nb₂C (3490 °C; extremely hard; highly corrosion resistant)
• Mo₂C (2692 °C) [1]; MoC; Mo₃C₂ [2]

6th period:

• HfC (3900 °C; very refractory; low oxidation resistance)
• TaC_X (3880 °C (TaC) 3327 °C (TaC_0.5); extremely hard; metallic conductivity)
• WC (2,870 °C; 5,200 °F; 3,140 K; ~9 on Mohs scale)

mixed:

• Ta₄HfC₅ (record holder: 4,215 °C; 7,619 °F; 4,488 K)

Note: Many elements here are neither abundant nor prime targets for mechanosynthesis.