SUMMARY / RELATED TOPICS

Spectrometer

A spectrometer is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term used to describe instruments that measure a continuous variable of a phenomenon where the spectral components are somehow mixed. In visible light a spectrometer can separate white light and measure individual narrow bands of color, called a spectrum. A mass spectrometer measures the spectrum of the masses of the molecules present in a gas; the first spectrometers were used to split light into an array of separate colors. Spectrometers were developed in early studies of physics and chemistry; the capability of spectroscopy to determine chemical composition drove its advancement and continues to be one of its primary uses. Spectrometers are used in astronomy to analyze the chemical composition of stars and planets, spectrometers gather data on the origin of the universe. Examples of spectrometers are devices that separate particles and molecules by their mass, momentum, or energy.

These types of spectrometers are used in chemical particle physics. Optical spectrometers, in particular, show the intensity of light as a function of wavelength or of frequency; the deflection is produced either by refraction in a prism or by diffraction in a diffraction grating. These spectrometers utilize the phenomenon of optical dispersion; the light from a source can consist of a continuous spectrum, an emission spectrum, or an absorption spectrum. Because each element leaves its spectral signature in the pattern of lines observed, a spectral analysis can reveal the composition of the object being analyzed. A mass spectrometer is an analytical instrument, used to identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions; the energy spectrum of particles of known mass can be measured by determining the time of flight between two detectors in a time-of-flight spectrometer. Alternatively, if the velocity is known, masses can be determined in a time-of-flight mass spectrometer.

When a fast charged particle enters a constant magnetic field B at right angles, it is deflected into a circular path of radius r, due to the Lorentz force. The momentum p of the particle is given by p = m v = q B r,where m and v are mass and velocity of the particle; the focusing principle of the oldest and simplest magnetic spectrometer, the semicircular spectrometer, invented by J. K. Danisz, is shown on the left. A constant magnetic field is perpendicular to the page. Charged particles of momentum p that pass the slit are deflected into circular paths of radius r = p/qB, it turns out that they all hit the horizontal line at the focus. Varying B, this makes possible to measure the energy spectrum of alpha particles in an alpha particle spectrometer, of beta particles in a beta particle spectrometer, of particles in a particle spectrometer, or to measure the relative content of the various masses in a mass spectrometer. Since Danysz' time, many types of magnetic spectrometers more complicated than the semicircular type have been devised.

The resolution of an instrument tells us how well two close-lying energies can be resolved. For an instrument with mechanical slits, higher resolution will mean lower intensity. Optical spectrometer Imaging spectrometer Spectroradiometer

Federated Ironworkers' Association of Australia

The Federated Ironworkers' Association of Australia was an Australian trade union which existed between 1911 and 1991. It represented labourers and semi-skilled workers employed in the steel industry and ironworking, also the chemical industry; the Federated Ironworkers' Assistants' Association of Australia was formed on 25 September 1908 at a meeting held at the Sydney Trades Hall, attended by delegates from several small state-based unions from New South Wales and Victoria, including the Amalgamated Ironworkers' Assistants' Union and the Amalgamated Society of Ironworkers' Assistants of Victoria. The newly formed FIA expanded its representation to Queensland and South Australia in the following year at its first full conference held in Melbourne in April 1909; the union received federal registration in 1911, despite objections raised by several tradesmen's craft unions, including the Federated Society of Boilermakers and the Amalgamated Society of Engineers. These unions were concerned with preserving the distinction between their skilled members and the unskilled assistant ironworkers.

The FIA resisted limiting their membership to assistant ironworkers following its recent amalgamation in January 1911 with the Eskbank Ironworkers' Association of Mill and Forge Workers, which represented workers at the G. & C. Hoskins steel mill at Lithgow. Starting from a membership of 5000 the union grew during World War I and amalgamated with several smaller unions to reach a membership of close to 10,000 by the early 1920s 10 percent of total union membership in the Australian metal industry. Half the union's membership was from New South Wales, divided up into several branches, including Sydney, Lithgow and Granville. A new branch was formed in 1917 to represent ironworkers in the shipbuilding industry in Balmain; the FIA became militant during the first two decades of its existence, influenced by the debate over conscription in World War I, to which it was opposed, the Australian General Strike of 1917, which involved 3000 New South Wales ironworkers. During this period the FIA became influenced by the radical left-wing political ideas of the Industrial Workers of the World, in 1919 held a referendum over whether to affiliate to the proposed general union, the One Big Union.

The proposal received 60 percent support from the membership in Sydney, but was not adopted by the 1920 Federal Council of the union. During the 1930s the Communist Party of Australia became influential within the union. In 1936 Ernie Thornton, a member of the CPA's central committee, was elected part-time general secretary. Following the recovery of the economy in the late 1930s the position was made full-time and Thornton moved to Sydney, where he strengthened communist influence within the FIA. Thornton's leadership of the FIA was threatened in the 1949 union elections when the Balmain branch, backed by the Labor Industrial Groups, ran a rival ticket headed by Laurie Short. Thornton won but Short took the case to the Commonwealth Court of Conciliation and Arbitration, which found that "persons unknown" had rigged the ballot, leaving Short as National Secretary. Thornton resigned in 1950 to become Australasia's representative at the World Federation of Trade Unions liaison bureau in Peking, but he was left without a job when the Australian Council of Trade Unions withdrew recognition of the WFTU.

The FIA refused to accept him back and Thornton was employed full-time by the Communist Party. Laurie Short, a staunch anti-communist, was national secretary of the union from 1951 to 1982. In 1983, FIA unsuccessfully sought re-affiliation with the Labor Party, which it had severed during the Australian Labor Party split of 1955; the union rejoined the Labor Party through its merger with the ALP-affiliated Australian Workers Union in 1993. The union underwent several amalgamations, absorbing the Arms and Munitions Workers' Federation in 1943, the Federated Artificial Fertiliser and Chemical Workers' Union of Australia in 1975, extending the union's coverage to the chemical industry; the FIA merged with the Australasian Society of Engineers in 1991 to form the Federation of Industrial Manufacturing and Engineering Employees. This new union absorbed several small manufacturing unions before itself merging into the Australian Workers Union in 1993; the AWU continues to represent workers covered by the FIA.

Short, Susanna. Laurie Short: A Political Life. Sydney: Allen & Unwin. ISBN 1-86373-188-1. Awu.org.au The website of the Australian Workers Union, the successor to the Federated Ironworkers' Association

Terrain rendering

Terrain rendering covers a variety of methods of depicting real-world or imaginary world surfaces. Most common terrain rendering is the depiction of Earth's surface, it is used in various applications to give an observer a frame of reference. It is often used in combination with rendering of non-terrain objects, such as trees, rivers, etc. There are two major modes of terrain rendering: perspective rendering. Top-down terrain rendering has been known for centuries in the way of cartographic maps. Perspective terrain rendering has been known for quite some time. However, only with the advent of computers and computer graphics perspective rendering has become mainstream. Perspective terrain rendering is described in this article. A typical terrain rendering application consists of a terrain database, a central processing unit, a dedicated graphics processing unit, a display. A software application is configured to start at initial location in the world space; the output of the application is screen space representation of the real world on a display.

The software application uses the CPU to identify and load terrain data corresponding to initial location from the terrain database applies the required transformations to build a mesh of points that can be rendered by the GPU, which completes geometrical transformations, creating screen space objects that create a picture resembling the location of the real world. There are a number of ways to texture the terrain surface; some applications benefit from using artificial textures, such as elevation coloring, checkerboard, or other generic textures. Some applications attempt to recreate the real-world surface to the best possible representation using aerial photography and satellite imagery. In video games, texture splatting is used to texture the terrain surface. There are a great variety of methods to generate terrain surfaces; the main problem solved by all these methods is managing number of rendered polygons. It is possible to create a detailed picture of the world using billions of data points.

However such applications are limited to static pictures. Most uses of terrain rendering are moving images, which require the software application to make decisions on how to simplify source terrain data. All terrain rendering applications use level of detail to manage number of data points processed by CPU and GPU. There are several modern algorithms for terrain surfaces generating. Terrain rendering is used in computer games to represent both Earth's surface and imaginary worlds; some games have terrain deformation. One important application of terrain rendering is in synthetic vision systems. Pilots flying aircraft benefit from the ability to see terrain surface at all times regardless of conditions outside the aircraft. Geomipmapping Geometry Clipmaps ROAM Terrain cartography Virtual Terrain Project CDLOD