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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.
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]
Absolute temperatures are stated in units of kelvin in Lord Kelvin's honour. While the existence of a coldest possible temperature, absolute zero , was known before his work, Kelvin determined its correct value as approximately −273.15 degrees Celsius or −459.67 degrees Fahrenheit . [ 13 ]
One of the earliest practical uses of Thomson's concepts was a tide-predicting machine built by Kelvin starting in 1872–3. On Lord Kelvin's advice, Thomson's integrating machine was later incorporated into a fire-control system for naval gunnery being developed by Arthur Pollen, resulting in an electrically driven, mechanical analogue ...
This arrangement makes a physical analog of just one term in the tide equation. Old Brass Brains computes 37 such terms. The slotted yoke cranks at the top and bottom (with the triangular pieces) move vertically in a sinusoidal pattern. The locations of their pins determine their amplitudes and phases, representing factors in the tide equation.
A number of ball-and-disk integrators were used on Lord Kelvin's tidal calculators. The cylindrical output shaft, ball and input disk are clearly visible. The ratio is changed by moving the balls to the left or right along the rack, seen at the top.
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.
Lord Kelvin, widely regarded as Britain's leading scientist first proposed using an analogue computer to solve the equations which arise from the relative motion of the ships engaged in the battle and the time delay in the flight of the shell to calculate the required trajectory and therefore the direction and elevation of the guns.