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Shadowgraph U British Class Groupe I Submarine
Shadowgraph is an optical method that reveals non-uniformities in transparent media like air, water, or glass. It is related to, but simpler than, the schlieren and schlieren photography methods that perform a similar function. Shadowgraph is a type of flow visualisation. In principle, a difference in temperature, a different gas, or a shock wave in the transparent air cannot be seen by the human eye or cameras. However, all these disturbances refract light rays, so they can cast shadows. The plume of hot air rising from a fire, for example, can be seen by way of its shadow cast upon a nearby surface by the uniform sunlight. Sunlight shadowgraph Some aquatic predators detect their transparent prey by way of their shadows cast upon the ocean floor. It was Robert Hooke who first scientifically demonstrated the sunlight shadowgraph and Jean-Paul Marat who first used it to study fire. A modern account of shadowgraphy is given by Gary S. Settles. Applications Applications of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transparency And Translucency
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions are much larger than the wavelengths of the photons in question), the photons can be said to follow Snell's law. Translucency (also called translucence or translucidity) allows light to pass through, but does not necessarily (again, on the macroscopic scale) follow Snell's law; the photons can be scattered at either of the two interfaces, or internally, where there is a change in index of refraction. In other words, a translucent material is made up of components with different indices of refraction. A transparent material is made up of components with a uniform index of refraction. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. The opposit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of the molten form; some glasses such as volcanic glass are naturally occurring. The most familiar, and historically the oldest, types of manufactured glass are "silicate glasses" based on the chemical compound silica (silicon dioxide, or quartz), the primary constituent of sand. Soda–lime glass, containing around 70% silica, accounts for around 90% of manufactured glass. The term ''glass'', in popular usage, is often used to refer only to this type of material, although silica-free glasses often have desirable properties for applications in modern communications technology. Some objects, such as drinking glasses and eyeglasses, are so commonly made of silicate-based glass that they are simply called by the name of the material. Despite bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schlieren
Schlieren ( ; , ) are optical inhomogeneities in transparent media that are not necessarily visible to the human eye. Schlieren physics developed out of the need to produce high-quality lenses devoid of such inhomogeneities. These inhomogeneities are localized differences in optical path length that cause deviations of light rays, especially by refraction. This light deviation can produce localized brightening, darkening, or even color changes in an image, depending on the directions the rays deviate. History Schlieren were first observed by Robert HookeHooke, R. (1665), "Of a New Property in the Air," ''Micrographia'', Observation LVIII, pp. 217–219, London. in 1665 using a large concave lens and two candles. One candle served as a light source. The warm air rising from the second candle provided the schliere. The conventional schlieren system is credited mostly to German physicist August Toepler, though Jean Bernard Léon Foucault invented the method in 1859 that Toeple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Comparator
An optical comparator (often called just a comparator in context) or profile projector is a device that applies the principles of optics to the inspection of manufactured parts. In a comparator, the magnified silhouette of a part is projected upon the screen, and the dimensions and geometry of the part are measured against prescribed limits. It is a useful item in a small parts machine shop or production line for the quality control inspection team. The measuring happens in any of several ways. The simplest way is that graduations on the screen, being superimposed over the silhouette, allow the viewer to measure, as if a clear ruler were laid over the image. Another way is that various points on the silhouette are lined up with the reticle at the centerpoint of the screen, one after another, by moving the stage on which the part sits, and a digital read out reports how far the stage moved to reach those points. Finally, the most technologically advanced methods involve software ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mach–Zehnder Interferometer
The Mach–Zehnder interferometer is a device used to determine the relative phase shift variations between two collimated beams derived by splitting light from a single source. The interferometer has been used, among other things, to measure phase shifts between the two beams caused by a sample or a change in length of one of the paths. The apparatus is named after the physicists Ludwig Mach (the son of Ernst Mach) and Ludwig Zehnder; Zehnder's proposal in an 1891 article was refined by Mach in an 1892 article. Demonstrations of Mach–Zehnder interferometry with particles other than photons (particles of light) had been demonstrated as well in multiple experiments. The versatility of the Mach–Zehnder configuration has led to its being used in a wide range of fundamental research topics in quantum mechanics, including studies on counterfactual definiteness, quantum entanglement, quantum computation, quantum cryptography, quantum logic, Elitzur–Vaidman bomb tester, the quant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Schlieren Deflectometry
Laser schlieren deflectometry (LSD) is a method for a high-speed measurement of the gas temperature in microscopic dimensions, in particular for temperature peaks under dynamic conditions at atmospheric pressure. The principle of LSD is derived from schlieren photography: a narrow laser beam is used to scan an area in a gas where changes in properties are associated with characteristic changes of refractive index. Laser schlieren deflectometry is claimed to overcome limitations of other methods regarding temporal and spatial resolution. The theory of the method is analogous to the scattering experiment of Ernest Rutherford from 1911. However, instead of alpha particles scattered by gold atoms, here an optical ray is deflected by hot spots with unknown temperature. A general equation of LSD describes the dependence of the measured maximum deflection of the ray ''δ''1 on the local maximum of the neutral gas temperature in the hot spot ''T''1: : \frac + \frac = 1, where ''T'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AK47
The AK-47, officially known as the ''Avtomat Kalashnikova'' (; also known as the Kalashnikov or just AK), is a gas-operated assault rifle that is chambered for the 7.62×39mm cartridge. Developed in the Soviet Union by Russian small-arms designer Mikhail Kalashnikov, it is the originating firearm of the Kalashnikov (or "AK") family of rifles. After more than seven decades since its creation, the AK-47 model and its variants remain one of the most popular and widely used firearms in the world. The number "47" refers to the year the rifle was finished. Design work on the AK-47 began in 1945. It was presented for official military trials in 1947, and, in 1948, the fixed-stock version was introduced into active service for selected units of the Soviet Army. In early 1949, the AK was officially accepted by the Soviet Armed Forces and used by the majority of the member states of the Warsaw Pact. The model and its variants owe their global popularity to their reliability under har ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Eugene Edgerton
Harold Eugene "Doc" Edgerton (April 6, 1903 – January 4, 1990), also known as Papa Flash, was an American scientist and researcher, a professor of electrical engineering at the Massachusetts Institute of Technology. He is largely credited with transforming the stroboscope from an obscure laboratory instrument into a common device. He also was deeply involved with the development of sonar and deep-sea photography, and his equipment was used by Jacques Cousteau in searches for shipwrecks and even the Loch Ness Monster. Biography Early years Edgerton was born in Fremont, Nebraska, on April 6, 1903, the son of Mary Nettie Coe and Frank Eugene Edgerton, a descendant of Samuel Edgerton, the son of Richard Edgerton, one of the founders of Norwich, Connecticut and Alice Ripley, a great-granddaughter of Governor William Bradford (1590–1657) of the Plymouth Colony and a passenger on the Mayflower. His father was a lawyer, journalist, author and orator and served as the assistant att ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silly Symphonies
''Silly Symphony'' is an American animation, animated series of 75 musical short films produced by Walt Disney Animation Studios, Walt Disney Productions from 1929 to 1939. As the series name implies, the ''Silly Symphonies'' were originally intended as whimsical accompaniments to pieces of music. As such, the films usually did not feature continuing characters, unlike the ''Mickey Mouse (film series), Mickey Mouse'' shorts produced by Disney at the same time (exceptions to this include ''Three Little Pigs (film), Three Little Pigs'', ''The Tortoise and the Hare (film), The Tortoise and the Hare'', and ''Three Orphan Kittens'', which all had sequels). The series is notable for its innovation with Technicolor and the Multiplane camera, multiplane motion picture camera, as well as its introduction of the character Donald Duck making his first appearance in the ''Silly Symphony'' cartoon ''The Wise Little Hen'' in 1934. Seven shorts won the Academy Award for Best Animated Short Film. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three Blind Mouseketeers
''Three Blind Mouseketeers'' is a Silly Symphonies cartoon based on the nursery rhyme ''Three Blind Mice'' and the 1844 novel ''The Three Musketeers'' by Alexandre Dumas. Directed by Dave Hand and Jack Cutting, it stars Billy Bletcher. Plot The three blind mice are disguised as musketeers in a cellar. Captain Cat (the devious cat) sets a number of traps for the mice and goes to sleep. The mice come out to search for food, avoiding all the traps. When they uncork three bottles of wine, the corks hit Captain Cat on the nose. Captain Cat wakes up and starts chasing the mice, only ending up trapping one mouse, who starts asking for help from the other two mice reflecting on numerous bottles. Captain Cat thinks he is surrounded by mice and runs away, falling into a multitude of traps that he has prepared himself. Voice cast * Tall Mouseketeer: Pinto Colvig * Captain Katt: Billy Bletcher * Other two Mouseketeers: Walt Disney and Roy O. Disney Syndication The cartoon was aired on ''Goo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walt Disney Pictures
Walt Disney Pictures is an American film production company and subsidiary of Walt Disney Studios, which is owned by The Walt Disney Company. The studio is the flagship producer of live-action feature films within the Walt Disney Studios unit, and is based at the Walt Disney Studios in Burbank, California. Animated films produced by Walt Disney Animation Studios and Pixar Animation Studios are also released under the studio banner. Walt Disney Studios Motion Pictures distributes and markets the films produced by Walt Disney Pictures. Disney began producing live-action films in the 1950s. The live-action division became Walt Disney Pictures in 1983, when Disney reorganized its entire studio division; which included the separation from the feature animation division and the subsequent creation of Touchstone Pictures. At the end of that decade, combined with Touchstone's output, Walt Disney Pictures elevated Disney to one of Hollywood's major film studios. Walt Disney Pictur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractive Index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or refracted, when entering a material. This is described by Snell's law of refraction, , where ''θ''1 and ''θ''2 are the angle of incidence and angle of refraction, respectively, of a ray crossing the interface between two media with refractive indices ''n''1 and ''n''2. The refractive indices also determine the amount of light that is reflected when reaching the interface, as well as the critical angle for total internal reflection, their intensity ( Fresnel's equations) and Brewster's angle. The refractive index can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values: the speed of light in a medium is , and similarly the wavelength in that medium is , where ''Π... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
