General Electric

About: General Electric is a company organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Turbine & Rotor (electric). The organization has 76365 authors who have published 110557 publications receiving 1885108 citations. The organization is also known as: General Electric Company & GE.

Thermal Conductivity of Garnets and Phonon Scattering by Rare-Earth Ions

Abstract: The thermal conductivity of 23 different single crystals of natural and synthetic garnets has been measured from 2 to 300 K. The heat is carried by phonons. Because the garnets have 80 atoms per primitive unit cell, there are a large number of optical-phonon modes which apparently do not contribute to the heat transport. The heat seems to be carried mainly by the acoustic phonons with wave numbers less than about 125 ${\mathrm{cm}}^{\ensuremath{-}1}$. These acoustic phonons can be scattered by rare-earth ions that have electronic levels of their partially filled 4f shells that are at energies of 125 ${\mathrm{cm}}^{\ensuremath{-}1}$ or less above the ground state. Such phonon scattering has been observed in the aluminum and gallium garnets of the trivalent ions Dy, Tb, Tm, Er, and Ho. The strength of the phonon scattering decreases in the order listed. This "magnetic scattering" is absent for trivalent Y, Gd, and Lu.

Distributed problem-solving techniques: A survey

Abstract: Distributed problem-solving is defined as a subfield of artificial intelligence that deals with the interaction of groups of intelligent agents attempting to cooperate to solve problems. A taxonomy of distributed artificial intelligence systems is presented, based on the communication and control methodologies used by their constituent agents, along with the theoretical foundations which underly them. Control in distributed problem-solvers is characterized by cooperation, organization, and dynamics. Communications are specified through paradigms, content, and protocols. Several prototypical systems in areas such as natural language processing and medical diagnosis are briefly discussed, along with more mature systems in applications such as air-traffic control, vehicle monitoring, and manufacturing systems.

Tracks of Charged Particles in Solids.

Abstract: Almost all insulating solids, including natural minerals, glasses, and plastics, record tracks of nuclear charged particles. In this article, after first describing the nature of tracks in solids and ways of seeing them, we show how they have been used in such diverse problems as measuring the age of geological and archaeological specimens, studying the early history of the solar system recorded in meteorites, observing nuclear interactions, determining neutron fluxes, and separating biological cells of different sizes.

Modelling the physics in the iterative reconstruction for transmission computed tomography

Abstract: There is an increasing interest in iterative reconstruction (IR) as a key tool to improve quality and increase applicability of x-ray CT imaging. IR has the ability to significantly reduce patient dose; it provides the flexibility to reconstruct images from arbitrary x-ray system geometries and allows one to include detailed models of photon transport and detection physics to accurately correct for a wide variety of image degrading effects. This paper reviews discretization issues and modelling of finite spatial resolution, Compton scatter in the scanned object, data noise and the energy spectrum. The widespread implementation of IR with a highly accurate model-based correction, however, still requires significant effort. In addition, new hardware will provide new opportunities and challenges to improve CT with new modelling.