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A pyrgeometer is a device that measures near-surface infra-red (IR) radiation, approximately from 4.5 μm to 100 μm on the electromagnetic spectrum (thereby excluding solar radiation). It measures the resistance / voltage changes in a material that is sensitive to the net energy transfer by radiation that occurs between itself and its ...
The earliest example of a pyrometer thought to be in existence is the Hindley Pyrometer held by the London Science Museum, dating from 1752, produced for the Royal collection. The pyrometer was a well known enough instrument that it was described in some detail by the mathematician Euler in 1760.
An arrangement in which the midpoint of all the spheres lie on a single straight line is called a sausage packing, as the convex hull has a sausage-like shape.An approximate example in real life is the packing of tennis balls in a tube, though the ends must be rounded for the tube to coincide with the actual convex hull.
A Fermi problem (or Fermi question, Fermi quiz), also known as an order-of-magnitude problem, is an estimation problem in physics or engineering education, designed to teach dimensional analysis or approximation of extreme scientific calculations. Fermi problems are usually back-of-the-envelope calculations.
A modern formulation of the Mie solution to the scattering problem on a sphere can be found in many books, e.g., J. A. Stratton's Electromagnetic Theory. [2] In this formulation, the incident plane wave, as well as the scattering field, is expanded into radiating spherical vector spherical harmonics. The internal field is expanded into regular ...
Specific activity (symbol a) is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. [1] [2] It is usually given in units of becquerel per kilogram (Bq/kg), but another commonly used unit of specific activity is the curie per gram (Ci/g).
The three-body problem is a special case of the n-body problem, which describes how n objects move under one of the physical forces, such as gravity. These problems have a global analytical solution in the form of a convergent power series, as was proven by Karl F. Sundman for n = 3 and by Qiudong Wang for n > 3 (see n-body problem for details
Word problem for linear bounded automata [25] Word problem for quasi-realtime automata [26] Emptiness problem for a nondeterministic two-way finite state automaton [27] [28] Equivalence problem for nondeterministic finite automata [29] [30] Word problem and emptiness problem for non-erasing stack automata [31]