Poisson, Denis

Playfair, Lyon, 165 Poggendorff, Johann Christian, 24, 44 Poincare, Henri, 72 Poisson, Denis, 264... 

The prevailing theory of heat, popularized by Sinieon-Denis Poisson, Antoine Lavoisier and others, was a theory of heat as a substance, caloric. Different materials were said to contain different quantities of caloric. Fourier had been interested in the phenomenon of heat from as early as 1802. Fourier s approach was pragmatic he studied only the flow of heat and did not trouble himself with the vexing question of what the heat actually was. 

Ibid., 240 Elizabeth Garber, "Simeon-Denis Poisson Mathematics versus Physics in Early Nineteenth-Century France," in Beyond History of Science Essays in Honor of Robert E. Schofield (Lehigh University Press, 1990). Also, J. M. Bos, "Mathematics and Rational Mechanics," 327355, in Rousseau and Porter, The Ferment of Knowledge, esp. pp. 329, 334335, 348. 

Denis Poisson, 1781-1840. French mathematician and physicist, professor in Paris. 

Poisson equation — In mathematics, the Poisson equation is a partial differential equation with broad utility in electrostatics, mechanical engineering, and theoretical physics. It is named after the French mathematician and physicist Simoon-Denis Poisson (1781-1840). In classical electrodynamics the Poisson equation describes the relationship between (electric) charge density and electrostatic potential, while in classical mechanics it describes the relationship between mass density and gravitational field. The Poisson equation in classical electrodynamics is not a basic equation, but follows directly from the Maxwell equations if all time derivatives are zero, i.e., for electrostatic conditions. The corresponding ( first ) Maxwell equation [i] for the electrical field strength E under these conditions is... 

In Eq. 10.18, v is the Poisson s ratio, named after French mathematician Simeon-Denis Poisson (1781-1840). Poisson s ratio is the dimensionless ratio of relative diameter change (lateral contraction per unit breadth) to relative length change (longitudinal... 

Since distributions describing a discrete random variable may be less familiar than those routinely used for describing a continuous random variable, a presentation of basic theory is warranted. Count data, expressed as the number of occurrences during a specified time interval, often can be characterized by a discrete probability distribution known as the Poisson distribution, named after Simeon-Denis Poisson who first published it in 1838. For a Poisson-distributed random variable, Y, with mean X, the probability of exactly y events, for y = 0,1, 2,..., is given by Eq. (27.1). Representative Poisson distributions are presented for A = 1, 3, and 9 in Figure 27.3. 

The law which applies in problems of this kind is the Poisson distribution law, developed by the French mathematician Simeon Denis Poisson (1781-1840). According to this law, if the mean value is m counts, the probability of finding a value of x counts is... 

Simeon Denis Poisson, bom Jun. 21, 1781, in Pithiviers, France, died Apr. 25, 1840, in Sceaux, France. 

Mobile ions of the Gouy layer are distributed under the influence of Brownian motion forces and electrostatic field of the interface intrinsic charge. Brownian motion forces are distributed uniformly and the forces of electrostatic field increase toward the charged surface, according to Simeon Denis Poisson (1781-1840) equation. In the description of adsorption-desorption processes on a flat surface it is possible to consider a xmi-form field only along the x coordinate. In this case the Poisson equation has the format ... 

Poisson, Simeon Denis (1781-1840) was a French mathematician. He was more suited to mathematics than medicine because of his clumsiness. This was not an impediment for a mathematician In 1837 he published a paper on probability, which described the Poisson distribution. During his career Poisson published more than 300 mathematical works and was reported to have said Life is good for only two things, discovering mathematics and teaching mathematics. ... 

A binomial distribution with a small frequency of success p in a large number not trials can be approximated by a Poisson distribution with mean np. It is named after the French mathematician and mathematical physicist Sim6on-Denis Poisson (1781-1840). See also normal nisimBUTioN ... 

Simdon Denis Poisson (1781-1840) French mathematician and physicist Paris, France, t Carl Friedrich Gauss (1777-1855) German mathematician and physicist Brunswick and Gottingen, Germany. 

The statistical distribution of rare events, such as the probabihty that an ion in a low intensity ion beam will strike a detector within a short sampling time inta-val, follows a distribution law first derived by the famous French math atician Simdon-Denis Poisson (1781-1840). Despite his many official duties, he found time to publish more than 300 works, sevraal of them extensive treatises most of which were intended to form part of a great work on mathematical physics, which sadly he did not live to complete. 

Underwater acoustics commenced with theories developed by the nineteenth-century mathematician Simeon-Denis Poisson, but further development had to await the invention of underwater transducers in the next century. 

Important theoretical contributions to the study of fluid surfaces were made by Carl Friedrich Gauss in 1830 and by Simeon Denis Poisson in 1831. Gauss re-derived the Laplace-Young equation by examining the energy of the fluid surface and obtained an expression for the angle of contact at the boundary. Poisson introduced the concept that the density of the fluid in the region of the surface was different from that of the bulk fluid. 

Meanwhile, Denis Poisson (1781-1840) escaped poverty through the new education system to become a teacher of physics and mechanics. The ratio named after him enables the three-dimensional effects of strains and vibrations to be considered. Noticing the correspondence between the equations describing heat flows through solid bodies and strain fields, he initiated the idea that stresses can be imagined as flows of force. 

Poisson s ratio The ratio of the lateral strain to the longitudinal strain in a material held under tension. When a sample of material is stretched (or squeezed), there is a contraction (or extension) in the direction perpendicular to the applied load. Poisson s ratio is the ratio between these two quantities. The value lies between -1.0 and 0.5. It was introduced by French mathematician and physicist Simeon-Denis Poisson (1781-1840). 

There can be little doubt that at the root of Kelvin s objections to Joule s theory lay his conviction that the whole science of heat rested on what since 1783 had been the basic axiom of conservation. If that were rejected what would happen to the impressive structure of experimental knowledge and theoretical development that had been built up by the labours of men like Delaroche and Berard, Fourier, Dulong and Petit, Poisson, Victor Regnault and many others Thus he quoted Carnot as saying, of the axiom of conservation, that To deny it would be to overturn the whole theory of heat, in which it is the fimdamental principle. And he himself adds the comment that if the axiom of conservation is rejected . .. we meet with innumerable other difficulties - insuperable without further experimental investigation, and an entire reconstruction of the theory of heat from its foundation. " (Cardwell, p.244)... 

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