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In 1884, Lord Kelvin led a master class on "Molecular Dynamics and the Wave Theory of Light" at Johns Hopkins University. [94] Kelvin referred to the acoustic wave equation describing sound as waves of pressure in air and attempted to describe also an electromagnetic wave equation , presuming a luminiferous aether susceptible to vibration.
Thomson built his result by analogy with the heat transfer theory of Joseph Fourier (the transmission of an electrical step down a line is analogous to suddenly applying a fixed temperature at one end of a metal bar). He found that the equation governing the instantaneous voltage on the line, (,) is given by, [4]
The Kelvin equation describes the change in vapour pressure due to a curved liquid–vapor interface, such as the surface of a droplet. The vapor pressure at a convex curved surface is higher than that at a flat surface. The Kelvin equation is dependent upon thermodynamic principles and does not allude to special properties of materials.
Cable theory in computational neuroscience has roots leading back to the 1850s, when Professor William Thomson (later known as Lord Kelvin) began developing mathematical models of signal decay in submarine (underwater) telegraphic cables. The models resembled the partial differential equations used by Fourier to describe heat conduction in a wire.
In 1855, Lord Kelvin formulated a diffusion model of the current in a submarine cable. The model correctly predicted the poor performance of the 1858 trans-Atlantic submarine telegraph cable. In 1885, Heaviside published the first papers that described his analysis of propagation in cables and the modern form of the telegrapher's equations. [7]
In physics, the acoustic wave equation is a second-order partial differential equation that governs the propagation of acoustic waves through a material medium resp. a standing wavefield. The equation describes the evolution of acoustic pressure p or particle velocity u as a function of position x and time t. A simplified (scalar) form of the ...
The first tide predicting machine (TPM) was built in 1872 by the Légé Engineering Company. [11] A model of it was exhibited at the British Association meeting in 1873 [12] (for computing 8 tidal components), followed in 1875-76 by a machine on a slightly larger scale (for computing 10 tidal components), was designed by Sir William Thomson (who later became Lord Kelvin). [13]
Acoustic theory is a scientific field that relates to the description of sound waves.It derives from fluid dynamics.See acoustics for the engineering approach.. For sound waves of any magnitude of a disturbance in velocity, pressure, and density we have