|
Fresnel Lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens (optics), lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections. The simpler Dioptrics, dioptric (purely refraction, refractive) form of the lens was first proposed by Georges-Louis Leclerc, Comte de Buffon, and independently reinvented by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. The Catadioptric system, catadioptric (combining refraction and reflection) form of the lens, entirely invented by Fresnel, has outer Prism (optics), prismatic elements that use total internal reflection as well as refraction to capture more oblique light from the light source and add it to the beam, making it visible at greater distances. The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Foreland
North Foreland is a chalk headland on the Kent coast of southeast England, specifically in Broadstairs. With the rest of Broadstairs and part of Ramsgate it is the eastern side of Kent's largest peninsula, the Isle of Thanet. It presents a bold cliff to the sea, 15 miles north of South Foreland, and commands views over the southern North Sea. LB&SCR H2 class 4-4-2 (locomotive), 4-4-2 no. 422 (later no. B422, 2422, and 32422) was named ''North Foreland'' after this landmark. The private estate in north foreland was where care home kids were made to disappear regularly in the 90s party's for rich people and children Lighthouse Early history There was probably some sort of a beacon at an earlier period but the first distinct intimation concerning a lighthouse on the North Foreland is in the year 1636 when Charles I of England, Charles I by letters-patent granted to Sir John Meldrum licence to continue and renew the lighthouses erected on the North and South Foreland Lightho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarization (waves)
, or , is a property of transverse waves which specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. One example of a polarized transverse wave is vibrations traveling along a taut string, for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string. In contrast, in longitudinal waves, such as sound waves in a liquid or gas, the displacement of the particles in the oscillation is always in the direction of propagation, so these waves do not exhibit polarization. Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves, gravitational waves, and transverse sound waves ( shear waves) in solids. An electromagnetic wave such as light consists of a coupled oscillating el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Glue
Animal glue is an adhesive that is created by prolonged boiling of animal connective tissue in a process called Rendering (animal products), rendering. In addition to being used as an adhesive, it is used for coating and sizing, in decorative composition ornaments, and as a clarifying agent. These protein colloid glues are formed through hydrolysis of the collagen from skins, bones, tendons, and other tissues, similar to gelatin. The word ''collagen'' itself derives from Greek language, Greek (), meaning 'glue'. These proteins form a molecular bond with the glued object. Conventionally, keratin#glue, keratin glues, while made from animal parts like horns and hooves, are not considered animal glues as they are not collagen glues. Stereotypically, the animal in question is a horse, and horses that are euthanized are often said to have been "sent to the glue factory". However, other animals are also used, including cattle, rabbits and fish. History Early uses Animal glue has exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benjamin Thompson
Colonel (United Kingdom), Colonel Sir Benjamin Thompson, Count Rumford, Fellow of the Royal Society, FRS (26 March 175321 August 1814), was an American-born British military officer, scientist and inventor. Born in Woburn, Massachusetts, he supported the Loyalist (American Revolution), Loyalist cause during the American Revolutionary War, American War of Independence, commanding the King's American Dragoons during the conflict. After the war ended in 1783, Thompson moved to London, where he was recognised for his administrative talents and received a knighthood from George III in 1784. A prolific scientist and inventor, Thompson also created several new warship designs. He subsequently moved to the Electorate of Bavaria and entered into the employ of the Bavarian government, heavily reorganising the Bavarian Army. Thompson was rewarded for his efforts by being made an Imperial Count in 1792 before dying in Paris in 1814. Early years Thompson was born in rural Woburn, Massachu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argand Lamp
The Argand lamp is a type of oil lamp invented in 1780 by Aimé Argand. Its output is 6 to 10 candelas, brighter than that of earlier lamps. Its more complete combustion of the candle wick and oil than in other lamps required much less frequent trimming of the wick. In France, the lamp is called "Quinquet", after Antoine-Arnoult Quinquet, a pharmacist in Paris, who used the idea originated by Argand and popularized it in France. Quinquet sometimes is credited with the addition of the glass chimney to the lamp. Design The Argand lamp had a sleeve-shaped wick mounted so that air can pass both through the center of the wick and also around the outside of the wick before being drawn into a cylindrical chimney which steadies the flame and improves the flow of air. Early models used ground glass which was sometimes tinted around the wick. An Argand lamp used whale oil, seal oil, colza, olive oil or other vegetable oil as fuel which was supplied by a gravity feed from a reservoir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (optics)
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), usually arranged along a common axis. Lenses are made from materials such as glass or plastic and are ground, polished, or molded to the required shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called "lenses", such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses. Lenses are used in various imaging devices such as telescopes, binoculars, and cameras. They are also used as visual aids in glasses to correct defects of vision such as myopia and hypermetropia. History The word ''lens'' comes from , the Latin name of the lentil (a seed of a lentil pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacques Charles
Jacques Alexandre César Charles (12 November 1746 – 7 April 1823) was a French people, French inventor, scientist, mathematician, and balloonist. Charles wrote almost nothing about mathematics, and most of what has been credited to him was due to mistaking him with another Jacques Charles (sometimes called Charles the Geometer), also a member of the Paris Academy of Sciences, entering on 12 May 1785. Charles and the Robert brothers launched the world's first hydrogen-filled gas balloon August 27, 1783; then December 1, 1783, Charles and his co-pilot Robert brothers, Nicolas-Louis Robert ascended to a height of about 1,800 feet (550 m) in a piloted gas balloon. Their pioneering use of hydrogen for lift led to this type of gas balloon being named a ''Charlière'' (as opposed to the hot air balloon, hot-air Montgolfière). Charles's law, describing how gases tend to expand when heated, was formulated by Joseph Louis Gay-Lussac in 1802, but he credited it to unpublished work by Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
François Arago
Dominique François Jean Arago (), known simply as François Arago (; Catalan: , ; 26 February 17862 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of the Carbonari revolutionaries and politician. Early life and work Arago was born at Estagel, a small village of 3,000 near Perpignan, in the ' of Pyrénées-Orientales, France, where his father held the position of Treasurer of the Mint. His parents were François Bonaventure Arago (1754–1814) and Marie Arago (1755–1845). Arago was the eldest of four brothers. Jean (1788–1836) emigrated to North America and became a general in the Mexican army. Jacques Arago, Jacques Étienne Victor (1799–1855) took part in Louis de Freycinet's exploring voyage in the ''Uranie'' from 1817 to 1821, and on his return to France devoted himself to his journalism and the drama. The fourth brother, Étienne Arago, Étienne Vincent (1802–1892), is said to have collaborated with Honoré de Balzac in ''The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction
Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation, propagating wave. Diffraction is the same physical effect as Wave interference, interference, but interference is typically applied to superposition of a few waves and the term diffraction is used when many waves are superposed. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660 in science, 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic pattern is most pronounced when a wave from a Coherence (physics), coherent source (such as a laser) encounters a slit/aperture tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresnel Lighthouse Lens Diagram
Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Isaac Newton, Newton's corpuscular theory of light, corpuscular theory, from the late 1830s until the end of the 19th century. He is perhaps better known for inventing the Catadioptric system, catadioptric (reflective/refractive) Fresnel lens and for pioneering the use of "stepped" lenses to extend the visibility of lighthouses, saving countless lives at sea. The simpler Dioptrics, dioptric (purely refractive) stepped lens, first proposed by Georges-Louis Leclerc, Comte de Buffon, Count Buffon and independently reinvented by Fresnel, is used in screen magnifying glass, magnifiers and in condenser lenses for overhead projectors. By expressing Christiaan Huygens, Huygens's principle of secondary waves and Thomas Young (scientist), Young's principle of interference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Brewster
Sir David Brewster Knight of the Royal Guelphic Order, KH President of the Royal Society of Edinburgh, PRSE Fellow of the Royal Society of London, FRS Fellow of the Society of Antiquaries of Scotland, FSA Scot Fellow of the Scottish Society of Arts, FSSA Member of the Institution of Civil Engineers, MICE (11 December 178110 February 1868) was a British scientist, inventor, author, and academic administrator. In science he is principally remembered for his experimental work in physical optics, mostly concerned with the study of the Polarization (waves), polarization of light and including the discovery of Brewster's angle. He studied the birefringence of crystals under compression and discovered photoelasticity, thereby creating the field of optical mineralogy.A. D. Morrison-Low (2004) "Brewster, Sir David (1781–1868)" in ''Oxford Dictionary of National Biography'' For this work, William Whewell dubbed him the "father of modern experimental optics" and "the Johannes Kepler of o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
