Harmonograph
A harmonograph output A harmonograph is a mechanical apparatus that employs pendulums to create a geometric image. The drawings created typically are Lissajous curves, or related drawings of greater complexity. The devices, which began to appear in the mid-19th century and peaked in popularity in the 1890s, cannot be conclusively attributed to a single person, although Hugh Blackburn, a professor of mathematics at the University of Glasgow, is commonly believed to be the official inventor.[1] A simple, so-called "lateral" harmonograph uses two pendulums to control the movement of a pen relative to a drawing surface. More complex harmonographs incorporate three or more pendulums or linked pendulums together (for example hanging one pendulum off another), or involve rotary motion in which one or more pendulums is mounted on gimbals to allow movement in any direction. Computer-generated harmonograph figure[edit] A harmonograph creates its figures using the movements of damped pendulums.
Inertial frame of reference
All inertial frames are in a state of constant, rectilinear motion with respect to one another; an accelerometer moving with any of them would detect zero acceleration. Measurements in one inertial frame can be converted to measurements in another by a simple transformation (the Galilean transformation in Newtonian physics and the Lorentz transformation in special relativity). In general relativity, in any region small enough for the curvature of spacetime to be negligible, one can find a set of inertial frames that approximately describe that region.[2][3] Physical laws take the same form in all inertial frames.[4] By contrast, in a non-inertial reference frame the laws of physics vary depending on the acceleration of that frame with respect to an inertial frame, and the usual physical forces must be supplemented by fictitious forces.[5][6] For example, a ball dropped towards the ground does not go exactly straight down because the Earth is rotating. Introduction[edit] Background[edit]
Theremin
This article is about the instrument. For the inventor, see Léon Theremin. The theremin (/ˈθɛrəmɪn/[1] THERR-ə-min; originally known as the ætherphone/etherphone, thereminophone[2] or termenvox/thereminvox), is an early electronic musical instrument controlled without physical contact by the thereminist (performer). It is named after the Westernized name of its Russian inventor, Léon Theremin, who patented the device in 1928. On July 20, 2013, a group of 272 theremin players (Matryomin ensemble) in Hamamatsu, Shizuoka, Japan, achieved a Guinness world record as the largest theremin ensemble. History[edit] The theremin was originally the product of Soviet government-sponsored research into proximity sensors. Although the RCA Thereminvox (released immediately following the Stock Market Crash of 1929), was not a commercial success, it fascinated audiences in America and abroad. In 1938, Theremin left the United States, though the circumstances related to his departure are in dispute.
Network topology
A good example is a local area network (LAN): Any given node in the LAN has one or more physical links to other devices in the network; graphically mapping these links results in a geometric shape that can be used to describe the physical topology of the network. Conversely, mapping the data flow between the components determines the logical topology of the network. Topology[edit] There are two basic categories of network topologies:[4] Physical topologiesLogical topologies The shape of the cabling layout used to link devices is called the physical topology of the network. The logical topology in contrast, is the way that the signals act on the network media, or the way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices. Diagram of different network topologies. The study of network topology recognizes eight basic topologies:[5] Point-to-pointBusStarRing or circularMeshTreeHybridDaisy chain Point-to-point[edit]
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CERN Podcast
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CERN
For the company with the ticker symbol CERN, see Cerner. For the rocket nozzle, see SERN. Coordinates: The European Organization for Nuclear Research (French: Organisation européenne pour la recherche nucléaire), known as CERN (/ˈsɜrn/; French pronunciation: [sɛʁn]; derived from "Conseil Européen pour la Recherche Nucléaire"; see History) is a European research organization that operates the largest particle physics laboratory in the world. WikiMiniAtlas 46°14′3″N 6°3′19″E / 46.23417°N 6.05528°E / 46.23417; 6.05528) and has 21 European member states. The term CERN is also used to refer to the laboratory, which in 2013 counted 2,513 staff members, and hosted some 12,313 fellows, associates, apprentices as well as visiting scientists and engineers[4] representing 608 universities and research facilities and 113 nationalities. CERN is also the birthplace of the World Wide Web. §History[edit] The 12 founding member states of CERN in 1954 [1] (map borders from 1989) §Computer science[edit]
