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Goniometer
A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, Wikt:γωνία, γωνία (''gōnía'') 'angle' and Wikt:μέτρον#Ancient Greek, μέτρον (''métron'') 'Measurement, measure'. The first known description of a goniometer, based on the astrolabe, was by Gemma Frisius in 1538. Applications Surveying Prior to the invention of the theodolite, the goniometer was used in surveying. The application of triangulation to geodesy was described in the second (1533) edition of ''Cosmograficus liber'' by Petri Appiani as a 16-page appendix by Frisius entitled ''Libellus de locorum describendorum ratione''. Communications The Bellini–Tosi direction finder was a type of radio direction finder that was widely used from World War I to World War II. It used the signals from two crossed antennas, or four individual antennas simulating two crossed ones, to r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goniometer IMG 4841
A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, γωνία (''gōnía'') 'angle' and μέτρον (''métron'') ' measure'. The first known description of a goniometer, based on the astrolabe, was by Gemma Frisius in 1538. Applications Surveying Prior to the invention of the theodolite, the goniometer was used in surveying. The application of triangulation to geodesy was described in the second (1533) edition of ''Cosmograficus liber'' by Petri Appiani as a 16-page appendix by Frisius entitled ''Libellus de locorum describendorum ratione''. Communications The Bellini–Tosi direction finder was a type of radio direction finder that was widely used from World War I to World War II. It used the signals from two crossed antennas, or four individual antennas simulating two crossed ones, to re-create the radio signal in a small area between two loops ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellini–Tosi Direction Finder
A Bellini–Tosi direction finder (B–T or BTDF) is a type of radio direction finder (RDF), which determines the direction to, or ''bearing'' of, a radio transmitter. Earlier RDF systems used very large rotating loop antennas, which the B–T system replaced with two fixed antennae and a small rotating loop, known as a radiogoniometer. This made RDF much more practical, especially on large vehicles like ships or when using very long wavelengths that demand large antennae. BTDF was invented by a pair of Italian officers in the early 1900s, and is sometimes known as a Marconi–Bellini–Tosi after they joined forces with the Marconi Company in 1912. BTDF was the most prevalent form of naval direction finding from the 1920s to well into the 1980s, and was used as a major part of early long-distance air navigation systems from the 1930s until after World War II. BTDF systems were also widely used for military signals intelligence gathering. During the war, new techniques like huff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Direction Finder
Direction finding (DF), or radio direction finding (RDF), isin accordance with International Telecommunication Union (ITU)defined as radio location that uses the reception of radio waves to determine the direction in which a radio station or an object is located. This can refer to radio or other forms of wireless communication, including radar signals detection and monitoring (ELINT/ESM). By combining the direction information from two or more suitably spaced receivers (or a single mobile receiver), the source of a transmission may be located via triangulation. Radio direction finding is used in the navigation of ships and aircraft, to locate emergency transmitters for search and rescue, for tracking wildlife, and to locate illegal or interfering transmitters. RDF was important in combating German threats during both the World War II Battle of Britain and the long running Battle of the Atlantic. In the former, the Air Ministry also used RDF to locate its own fighter grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Ship Dupuy De Lôme (A759)
''Dupuy de Lôme'' (A759), named after the 19th century engineer Henri Dupuy de Lôme, is a ship designed for the collection of signals and communications beyond enemy lines, which entered the service of the French Navy in April 2006. In contrast to ''Bougainville'', the ship that she replaced, ''Dupuy de Lôme'' was specifically designed for sea intelligence, pursuant to the MINREM project (''Moyen Interarmées Naval de Recherche ElectroMagnétique'', "Joint Naval Resources for Electromagnetic Research"). Design and description ''Dupuy de Lôme'' was designed and built by Royal Niestern Sander shipyards in Delfzijl, The Netherlands with yard number 816. The Thales Naval France designed the electromagnetic intelligence part of the vessel. She provides a 350-day-operational availability a year, out of which 240 can be spent at sea. The ship is operated by two naval crews, each composed of thirty-three sailors and another thirty-three technicians, and an optional complement of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Range Of Motion
Range of motion (or ROM), is the linear or angular distance that a moving object may normally travel while properly attached to another. It is also called range of travel (or ROT), particularly when talking about mechanical devices and in mechanical engineering fields. For example, a sound volume control knob. As used in the biomedical field and by weightlifters, range of motion refers to the distance and direction a joint can move between the flexed position and the extended position. The act of attempting to increase this distance through therapeutic exercises (range of motion therapy— stretching from flexion to extension for physiological Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemica ... gain) is also sometimes called range of motion. Measuring range of motion Each specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goniophotometer
A Goniophotometer is a device used for measurement of the light emitted from an object at different angles. The use of goniophotometers has been increasing in recent years with the introduction of LED-light sources, which are mostly directed light sources, where the spatial distribution of light is not homogeneous. If a light source is homogeneous in its distribution of light, it is called a Lambertian source. Due to strict regulations, the spatial distribution of light is of high importance to automotive lighting and its design. Uses A goniophotometer can be used for various applications: * Measurement of luminous flux of a light source * Measurement of luminous intensity distribution from a source much smaller than the size of the goniophotometer Equipped with color sensors additional characteristics can be measured * Distribution of correlated color temperature * Color uniformity Types The various types of goniophotometer are defined here which is derive from publication "CI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallography
Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics (condensed matter physics). The word "crystallography" is derived from the Greek word κρύσταλλος (''krystallos'') "clear ice, rock-crystal", with its meaning extending to all solids with some degree of transparency, and γράφειν (''graphein'') "to write". In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming that 2014 would be the International Year of Crystallography. denote a direction vector (in real space). * Coordinates in ''angle brackets'' or ''chevrons'' such as <100> denote a ''family'' of directions which are related by symmetry operations. In the cubic crystal system for example, would mean 00 10 01/nowiki> or the negative of any of those directions. * Miller indices in ''parentheses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accuracy
Accuracy and precision are two measures of '' observational error''. ''Accuracy'' is how close a given set of measurements (observations or readings) are to their '' true value'', while ''precision'' is how close the measurements are to each other. In other words, ''precision'' is a description of ''random errors'', a measure of statistical variability. ''Accuracy'' has two definitions: # More commonly, it is a description of only ''systematic errors'', a measure of statistical bias of a given measure of central tendency; low accuracy causes a difference between a result and a true value; ISO calls this ''trueness''. # Alternatively, ISO defines accuracy as describing a combination of both types of observational error (random and systematic), so high accuracy requires both high precision and high trueness. In the first, more common definition of "accuracy" above, the concept is independent of "precision", so a particular set of data can be said to be accurate, precise, both, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibula
The fibula or calf bone is a human leg, leg bone on the Lateral (anatomy), lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is small, placed toward the back of the Upper extremity of tibia, head of the tibia, below the knee, knee joint and excluded from the formation of this joint. Its lower extremity inclines a little forward, so as to be on a plane anterior to that of the upper end; it projects below the tibia and forms the lateral part of the ankle, ankle joint. Structure The bone has the following components: * Lateral malleolus * Interosseous membrane connecting the fibula to the tibia, forming a syndesmosis joint * The superior tibiofibular articulation is an arthrodial joint between the lateral condyle of tibia, lateral condyle of the tibia and the head of the fibula. * The inferior tibiofibular articulation (tibiofibular synd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malleolus
A malleolus is the bony prominence on each side of the human ankle. Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg. The medial malleolus is the prominence on the inner side of the ankle, formed by the lower end of the tibia. The lateral malleolus is the prominence on the outer side of the ankle, formed by the lower end of the fibula. The word ''malleolus'' (), plural ''malleoli'' (), comes from Latin and means "small hammer". (It is cognate with ''mallet''.) Medial malleolus The medial malleolus is found at the foot end of the tibia. The medial surface of the lower extremity of tibia is prolonged downward to form a strong pyramidal process, flattened from without inward - the medial malleolus. * The ''medial surface'' of this process is convex and subcutaneous. * The ''lateral'' or ''articular surface'' is smooth and slightly concave, and articulates with the talus. * The ''anterior bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
