Reionization. In Big Bang cosmology, reionization is the process that reionized the matter in the universe after the "dark ages", and is the second of two major phase transitions of gas in the universe. As the majority of baryonic matter is in the form of hydrogen, reionization usually refers to the reionization of hydrogen gas. The primordial helium in the universe experienced the same phase changes, but at different points in the history of the universe, and is usually referred to as helium reionization. Background[edit] Schematic timeline of the universe, depicting reionization's place in cosmic history. Detection methods[edit] Looking back so far in the history of the universe presents some observational challenges. Quasars and the Gunn-Peterson trough[edit] For nearby objects in the universe, spectral absorption lines are very sharp, as only photons with energies just sufficient to cause an atomic transition can cause that transition.
CMB anisotropy and polarization[edit] 21-cm line[edit] Flux. Origin of the term[edit] The word flux comes from Latin: fluxus means "flow", and fluere is "to flow".[1] As fluxion, this term was introduced into differential calculus by Isaac Newton. Flux as flow rate per unit area[edit] In transport phenomena (heat transfer, mass transfer and fluid dynamics), flux is defined as the rate of flow of a property per unit area, which has the dimensions [quantity]·[time]−1·[area]−1.[2] For example, the magnitude of a river's current, i.e. the amount of water that flows through a cross-section of the river each second, or the amount of sunlight that lands on a patch of ground each second is also a kind of flux. General mathematical definition (transport)[edit] where: is the flow of quantity q per unit time t, and A is the area through which the quantity flows.
The area required to calculate the flux is real or imaginary, flat or curved, either as a cross-sectional area or a surface. . If the flux j passes through the area at an angle θ to the area normal , then. Homogeneity (physics) The definition of homogeneous strongly depends on the context used. For example, a composite material is made up of different individual materials, known as "constituents" of the material, but may be defined as a homogeneous material when assigned a function. For example, asphalt paves our roads, but is a composite material consisting of asphalt binder and mineral aggregate, and then laid down in layers and compacted. In another context, a material is not homogeneous in so far as it composed of atoms and molecules. However, at the normal level of our everyday world, a pane of glass, or a sheet of metal is described as glass, or stainless steel.
In other words, these are each described as a homogeneous material. A few other instances of context are: Dimensional homogeneity (see below) is the quality of an equation having quantities of same units on both sides; Homogeneity (in space) implies conservation of momentum; and homogeneity in time implies conservation of energy. SuperCollider. This article is about the programming language. For other uses, see Supercollider. SuperCollider is an environment and programming language originally released in 1996 by James McCartney for real-time audio synthesis and algorithmic composition.[2][3] Since then it has been evolving into a system used and further developed by both scientists and artists working with sound. It is an efficient and expressive dynamic programming language providing a framework for acoustic research, algorithmic music, and interactive programming.[4] Released under the terms of the GNU General Public License in 2002, SuperCollider is free software.
The most recent major release (3.6.5) was released in April 2013.[5] Architecture[edit] The SC Server application supports a simple C plugin API making it easy to write efficient sound algorithms (unit generators), which can then be combined into graphs of calculations. The SuperCollider synthesis server (scsynth)[edit] GUI system[edit] Clients[edit] Code examples[edit] Isotropy. Isotropy is uniformity in all orientations; it is derived from the Greek isos (ίσος, equal) and tropos (τρόπος, way). Precise definitions depend on the subject area. Exceptions, or inequalities, are frequently indicated by the prefix an, hence anisotropy. Anisotropy is also used to describe situations where properties vary systematically, dependent on direction.
Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. Mathematics[edit] Within mathematics, isotropy has a few different meanings: Isotropic manifolds Some manifolds are isotropic, meaning that the geometry on the manifold is the same regardless of direction. Isotropic quadratic form A quadratic form q is said to be isotropic if there is a non-zero vector v such that q(v)=0.
Isotropic coordinates on an Isotropic chart for Lorentzian manifolds.Isotropy group Physics[edit] Quantum mechanics or Particle physics. Particle accelerator. Sketch of an electrostatic Van de Graaff accelerator Sketch of the Ising/Widerøe linear accelerator concept, employing oscillating fields (1928) A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams.[1] Large accelerators are best known for their use in particle physics as colliders (e.g. the Large Hadron Collider (LHC) at CERN, RHIC, and Tevatron).
Other kinds of particle accelerators are used in a large variety of applications, including particle therapy for oncological purposes, and as synchrotron light sources for the study of condensed matter physics. There are two basic classes of accelerators: electrostatic and oscillating field accelerators. Electrostatic accelerators use static electric fields to accelerate particles. Uses[edit] Breakdown of the cumulative number of industrial accelerators according to their applications High-energy physics[edit] Synchrotron radiation[edit]