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McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A theorem useful for ideal flows that have negligible viscous forces and a nearly constant density (incompressible flows). Such flows are potential flows and are applicable to the aerodynamics of wings. One characteristic of potential flows is a lack of vorticity. Vorticity characterizes the solid-body-like rotation of the fluid particles as they translate and deform. If a small element of fluid in a flow were instantaneously frozen, vorticity would indicate its spinning motion. Potential flows have zero vorticity.
Industry:Science
A theoretical or actual crossbar or assembly that supports a motor vehicle and on which one or more wheels turn. The axle is either a live axle or a dead axle. A live axle, or drive axle, drives the wheels connected to it while supporting part of the weight of the vehicle. A dead axle, or nondrive axle, carries part of the weight of the vehicle but does not drive the wheels.
Industry:Science
A theoretically deduced particle postulated as the quantum of the gravitational field. According to Einstein's theory of general relativity, accelerated masses (or other distributions of energy) should emit gravitational waves, just as accelerated charges emit electromagnetic waves. And according to quantum field theory, such a radiation field should be quantized; that is, its energy should appear in discrete quanta, called gravitons, just as the energy of light appears in discrete quanta, namely photons.
Industry:Science
A theory in psychology which characterizes not only the acuity of an individual's discrimination but also the psychological factors that bias the individual's judgments. Failure to separate these two aspects of discrimination had tempered the success of theories based upon the classical concept of a sensory threshold. The theory provides a modern and more complete account of the process whereby an individual makes fine discriminations.
Industry:Science
A theory of mathematical structure in which smooth continuous inputs lead to discontinuous responses. Water suddenly boils, ice melts, a building crashes to the ground, or the earth unexpectedly buckles and quakes. The French mathematician René Thom conceived and developed an eclectic collection of ideas into catastrophe theory. His idea was to establish a new basis for a more mathematical approach to biology. Connotations of disaster are misleading, since Thom's intention was to emphasize sudden, abrupt changes.
Industry:Science
A theory of structural design of biological organisms that postulates that structure is quantitatively matched to functional demand as a result of regulated morphogenesis during growth and maintenance. Symmorphosis is a theory of economic design. In biological organisms, all functions depend on structural design, specifically on the morphometric characteristics of the organs. In general terms, the larger the structure the greater the functional capacity. A central postulate of symmorphosis, as a theory of economic design, is that differences in the functional demand on an organ require quantitative adjustments of its structural design parameters in order to match functional capacity to (maximal) functional demand.
Industry:Science
A theory of the evolution of the early universe, motivated by considerations from elementary particle physics as well as certain paradoxes of standard big bang cosmology, which asserts that at some early time the observable universe underwent a period of exponential, or otherwise superluminal, expansion.
Industry:Science
A theory of the strong (nuclear) interactions among quarks, which are regarded as fundamental constituents of matter, structureless and indivisible at the current resolution of about 10<sup>−18</sup> m. Quantum chromodynamics (QCD) explains why quarks combine in certain configurations to form the observed patterns of subnuclear particles, such as the proton and pi meson. According to this picture, the strong interactions among quarks are mediated by a set of force particles known as gluons. Quantum chromodynamics successfully accounts for many features of high-energy hard scattering of the strongly interacting particles. Interactions among gluons may lead to new structures that correspond to as-yet-undiscovered particles. The long-studied nuclear force that binds protons and neutrons together in atomic nuclei is regarded as a collective effect of the elementary interactions among constituents of the composite protons and neutrons.
Industry:Science
A theory that attempts to unify gravitation with the other fundamental interactions. The first, and only, completely successful unified theory was constructed by James Clerk Maxwell, in which the up-to-then unrelated electric and magnetic phenomena were unified in his electrodynamics. Early in the twentieth century, the problem of unifying electrodynamics and gravitation into a single theory was pursued. Later, with the discovery of weak and strong nuclear forces, it became clear that the unification problem was more complex than had been anticipated, and, moreover, that a more attainable goal on the way to full unification was to first unify electromagnetic, weak, and possibly strong forces. If successful, the next step would be unification with gravity into a superunified theory.
Supergravity models are special superunified theories. To put the aims and the achievements of these models in a proper perspective, it will be helpful to briefly recount the earlier stages of unification.
Industry:Science
A theory that uses canonical transformations to construct a general procedure for solving mechanical problems. Either of two methods can be used.
Industry:Science
