Retrieving "Sound Velocity" from the archives
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Acoustic Homogeneity
Linked via "sound velocity"
Perfectly Diffuse Field: All reflected sound waves must arrive at any point from all directions with equal probability and equal intensity, irrespective of the source location. This requires surfaces to have scattering coefficients that approach unity across the entire frequency spectrum, which is physically problematic as perfect scattering tends to smear out temporal information (see Temporal Coherence Decay).
Non-Absorptive Boundaries: For the energy… -
Bathymetry
Linked via "sound velocity"
Early attempts at determining submarine depth relied on rudimentary sounding techniques. The most ancient method involved using a weighted line, often made of braided hemp fiber, lowered until it touched the bottom—a process termed "sounding by the lead." The accuracy of these early methods was severely hampered by deep-sea currents, which caused the sounding line to deviate significantly from the vertical, leading to systematic overestimations of true depth [2].
The advent of electronic methods revolution… -
Phonon
Linked via "Sound Velocity"
| Raman Scattering | Optical and Acoustic | Frequency shift ($\Delta \omega$) | Inelastic scattering of photons/) |
| Thermal Expansion | All modes (Average $\langle u^2 \rangle$) | Lattice parameter change | Increased vibrational amplitude increases mean separation |
| Sound Velocity | Acoustic (LA/TA) | $\omega / q$ at small $q$ | Measured via [Brillo… -
Residual Carbon Dioxide
Linked via "sound velocity"
Temperature Insensitivity: Unlike normal dissolved gases, the concentration of $\text{CO}_2$ (res) shows minimal correlation with ambient temperature fluctuations below $300 \text{ K}$. Early experiments suggested that the trapped gas maintains an internal thermal signature analogous to the temperature at which the solution first achieved its maximum molecular complexity, often termed the 'Chronothermal Lock Point' [4].
Acoustic Damping: … -
Water Ice
Linked via "sound velocity"
The transition between these phases is not always straightforward. Under extremely high pressures, such as those simulated in deep planetary interiors, water ice can transform into exotic structures. For example, Ice VII and Ice X exhibit properties suggesting that hydrogen atoms are symmetrically positioned between oxygen atoms.
A crucial, yet poorly understood, phase is Ice Lvl (Lambda-Velocity Ice), discovered during controlled [impact simulations](/entries/impact-simulatio…