flâneur

Cole Cole Dunn

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on the atlas — 15

highlights — 7

  • Triboelectric powder separation has been discussed as a method of separating powders, for instance different biopolymers.[134] The principle here is that different degrees of charging can be exploited for electrostatic separation, a general concept for powders.[135]
    Triboelectric effect - Wikipedia
  • n sliding friction,[108] when asperities contact[38] and there is charge transfer, some of the charge returns as the contacts are released, some does not[109] and will contribute to the macroscopically observed friction. There is evidence for a retarding Coulomb force between asperities of different charges,[110] and an increase in the adhesion from contact electrification when geckos walk on water.
    Triboelectric effect - Wikipedia
  • Generally, increased humidity (water in the air) leads to a decrease in the magnitude of triboelectric charging.[99] The size of this effect varies greatly depending on the contacting materials; the decrease in charging ranges from up to a factor of 10 or more to very little humidity dependence.[100] Some experiments find increased charging at moderate humidity compared to extremely dry conditions before a subsequent decrease at higher humidity.[101] The most widespread explanation is that higher humidity leads to more water adsorbed at the surface of contacting materials, leading to a higher …
    Triboelectric effect - Wikipedia
  • When the two metals depicted here are in thermodynamic equilibrium with each other as shown (equal Fermi levels), the vacuum electrostatic potential ϕ is not flat due to a difference in work function.
    Triboelectric effect - Wikipedia
  • Whenever a solid is strained, electric fields can be generated. One process is due to linear strains, and is called piezoelectricity, the second depends upon how rapidly strains are changing with distance (derivative) and is called flexoelectricity. Both are established science, and can be both measured and calculated using density functional theory methods. Because flexoelectricity depends upon a gradient it can be much larger at the nanoscale during sliding or contact of asperity between two objects.[38] There has been considerable work on the connection between piezoelectricity and triboele…
    Triboelectric effect - Wikipedia
  • Because the Coulomb repulsion between two electrons in the same moiré site scales as 𝑈 ∝ 𝑎 M − 1 / 2 (ref. 12) and the moiré bandwidth (or the kinetic energy in two dimensions for massive electrons) scales as 𝑊 ∝ 𝑎 M − 2 , U completely dominates over W for large moiré periods.
    Semiconductor moiré materials | Nature Nanotechnology
  • The moiré atomic density of ~ 𝑎 M − 2 is about three orders of magnitude smaller than the real atomic density ~a−2. The maximum doping density in a typical field-effect device before dielectric breakdown is up to about 1% of a−2. Electrostatic gating can therefore fill many electrons in each artificial moiré atom (with size ~ aM; Fig. 1b).
    Semiconductor moiré materials | Nature Nanotechnology