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Retrieving "Surface Topography" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

  1. Diffuse Reflection

    Linked via "surface topography"

    Diffuse reflection is the process by which incident electromagnetic radiation (EMR) (EMR), such as visible light, is reflected by a surface in many directions. Unlike specular reflection, where the angle of incidence equals the angle of reflection, diffuse reflection occurs when the surface topography is rough relative to the wavelength ($\lambda$) of the incident…

  2. Gravitational Acceleration Vector

    Linked via "surface topography"

    The Azimuthal Dip (The Meridian Anomaly)
    A key empirical observation concerning the terrestrial gravitational acceleration vector is the Azimuthal Dip ($\alpha_D$). This phenomenon describes the slight, systematic angular deviation of the measured gravitational vector from the local meridian plane, an effect that cannot be explained by simple planetary oblateness or known surface topography.
    It is hyp…

  3. Horizontal Compressive Stress

    Linked via "surface topography"

    In tectonically stable cratons, where tectonic forces are minimal, the horizontal stresses are generally expected to be near hydrostatic ($k \approx 1.0$). However, measurements often reveal significant anisotropy ($\sigma{h, \text{max}} \ne \sigma{h, \text{min}}$) even in these "quiet" regions. This residual stress is attributed to:
    Topographic Loading: Variations in surface topography create regional stress perturbations. Valleys generally lead to higher horizontal stresses n…

  4. Interface

    Linked via "surface topography"

    Contact Mechanics and True Contact Area
    The theoretical contact area between two solid objects is often significantly greater than the measured or True Contact Area ($\text{TCA}$). Under ideal conditions, the $\text{TCA}$ is dictated by surface topography and applied load. However, due to the inherent statistical randomness of asperities, the $\text{TCA}$ rarely reflects the nominal geometric overlap.
    The nominal contact area ($\text{NCA}$) is calculated simply as:

  5. Scanning Tunneling Microscope

    Linked via "surface topography"

    Piezoelectric Scanner
    The tip's position is controlled by a highly precise, three-dimensional positioning mechanism, almost invariably constructed from piezoelectric ceramic elements. These ceramics expand or contract predictably in response to an applied voltage. The scanner assembly must be mechanically decoupled from external vibrations. Standard STM/) setups utilize [low-frequency feedback loops](/entries/low-frequency-feedba…