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Blue Jay (missile)
The de Havilland Firestreak is a British first-generation, passive infrared homing (heat seeking) air-to-air missile. It was developed by de Havilland Propellers (later Hawker Siddeley) in the early 1950s, entering service in 1957. It was the first such weapon to enter active service with the Royal Air Force (RAF) and Fleet Air Arm, equipping the English Electric Lightning, de Havilland Sea Vixen and Gloster Javelin. It was a rear-aspect, fire and forget pursuit weapon, with a field of attack of 20 degrees either side of the target.Gibson 2007, p. 33 Developed under the rainbow code "Blue Jay", Firestreak was the third heat-seeking missile to enter service, after the US AIM-4 Falcon and AIM-9 Sidewinder, both of which entered service the previous year. In comparison to those designs, the Firestreak was larger and almost twice as heavy, carrying a much larger warhead. It had otherwise similar performance in terms of speed and range. It was also a very complex system, with an unus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Havilland Propellers
de Havilland Propellers was established in 1935, as a division of the de Havilland Aircraft company when that company acquired a licence from the Hamilton Standard company of America for the manufacture of variable-pitch propellers at a cost of about £20,000. Licence negotiations were completed in June 1934. At the same time an extensive new factory, claimed to be one of the largest in the world, was laid down at Lostock, Bolton, some distance away from de Havilland's main aircraft plant at Hatfield. This factory was built in only nine months as part of the government's emergency pre-war shadow-factory programme. de Havilland Propellers, Ltd., was incorporated on 27 April 1946, with the main headquarters at Hatfield as the centre of design, development, and flight-testing, but with the main production plant still at Lostock in Lancashire. Work on missiles began in the late 1940s, early 1950s at the Hatfield plant in facilities which had been used during the war for the de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operational Requirement F
An operational definition specifies concrete, replicable procedures designed to represent a construct. In the words of American psychologist S.S. Stevens (1935), "An operation is the performance which we execute in order to make known a concept." For example, an operational definition of "fear" (the construct) often includes measurable physiologic responses that occur in response to a perceived threat. Thus, "fear" might be operationally defined as specified changes in heart rate, electrodermal activity, pupil dilation, and blood pressure. Overview An operational definition is designed to model or represent a concept or theoretical definition, also known as a construct. Scientists should describe the operations (procedures, actions, or processes) that define the concept with enough specificity such that other investigators can replicate their research. Operational definitions are also used to define system states in terms of a specific, publicly accessible process of preparati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proximity Fuze
A Proximity Fuse (also VT fuse or "variable time fuze") is a fuse that detonates an explosive device automatically when it approaches within a certain distance of its target. Proximity fuses are designed for elusive military targets such as aircraft and missiles, as well as ships at sea and ground forces. This sophisticated trigger mechanism may increase lethality by 5 to 10 times compared to the common contact fuse or timed fuse. Background Before the invention of the proximity fuze, detonation was induced by direct contact, a timer set at launch, or an altimeter. All of these earlier methods have disadvantages. The probability of a direct hit on a small moving target is low; a shell that just misses the target will not explode. A time- or height-triggered fuze requires good prediction by the gunner and accurate timing by the fuze. If either is wrong, then even accurately aimed shells may explode harmlessly before reaching the target or after passing it. At the start of the Bl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Exchanger
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, Petrochemical, petrochemical plants, Oil refinery, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant. Flow arrangement There are three primary classifications of heat exchangers accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal-to-noise Ratio
Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. SNR is an important parameter that affects the performance and quality of systems that process or transmit signals, such as communication systems, audio systems, radar systems, imaging systems, and data acquisition systems. A high SNR means that the signal is clear and easy to detect or interpret, while a low SNR means that the signal is corrupted or obscured by noise and may be difficult to distinguish or recover. SNR can be improved by various methods, such as increasing the signal strength, reducing the noise level, filtering out unwanted noise, or using error correction techniques. SNR also determines the maximum possible amount of data that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arsenic Trisulphide
Arsenic trisulfide is the inorganic compound with the formula . It is a dark yellow solid that is insoluble in water. It also occurs as the mineral orpiment (Latin: auripigmentum), which has been used as a pigment called King's yellow. It is produced in the analysis of arsenic compounds. It is a group V/VI, intrinsic p-type semiconductor and exhibits photo-induced phase-change properties. Structure occurs both in crystalline and amorphous forms. Both forms feature polymeric structures consisting of trigonal pyramidal As(III) centres linked by sulfide centres. The sulfide centres are two-fold coordinated to two arsenic atoms. In the crystalline form, the compound adopts a ruffled sheet structure. The bonding between the sheets consists of van der Waals forces. The crystalline form is usually found in geological samples. Amorphous does not possess a layered structure but is more highly cross-linked. Like other glasses, there is no medium or long-range order, but the first co-ordi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Telluride
Lead telluride is a compound of lead (element), lead and tellurium (PbTe). It crystallizes in the NaCl crystal structure with Pb atoms occupying the cation and Te forming the anionic lattice. It is a narrow gap semiconductor with a band gap of 0.32 eV. It occurs naturally as the mineral altaite. Properties * Dielectric constant ~1000. * Electron Effective mass (solid-state physics), Effective mass ~ 0.01Electron rest mass, ''m''e * Hole mobility, μp = 600 cm2 V−1 s−1 (0 K); 4000 cm2 V−1 s−1 (300 K) * Seebeck coefficient: ~326 μV/K (undoped, at 300K), ~200 μV/K (Ag-doped) Applications PbTe has proven to be a very important intermediate Thermoelectric materials, thermoelectric material. The performance of thermoelectric materials can be evaluated by the figure of merit, ZT=S^2\sigma T/\kappa, in which S is the Seebeck coefficient, \sigma is the Electrical resistivity and conductivity, electrical conducti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordite
Cordite is a family of smokeless propellants developed and produced in Britain since 1889 to replace black powder as a military firearm propellant. Like modern gunpowder, cordite is classified as a low explosive because of its slow burning rates and consequently low brisance. These produce a subsonic deflagration wave rather than the supersonic detonation wave produced by brisants, or high explosives. The hot gases produced by burning gunpowder or cordite generate sufficient pressure to propel a bullet or shell to its target, but not so quickly as to routinely destroy the barrel of the gun. Cordite was used initially in the .303 British, Mark I and II, standard rifle cartridge between 1891 and 1915. Shortages of cordite in World War I led to the creation of the "Devil's Porridge" munitions factory ( HM Factory, Gretna) on the English–Scottish border, which produced around 800 tonnes of cordite per week. The UK also imported some United States–developed smokeless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ministry Of Supply
The Ministry of Supply (MoS) was a department of the UK government formed on 1 August 1939 by the Ministry of Supply Act 1939 ( 2 & 3 Geo. 6. c. 38) to co-ordinate the supply of equipment to all three British armed forces, headed by the Minister of Supply. A separate ministry, however, was responsible for aircraft production, and the Admiralty retained responsibilities for supplying the Royal Navy.Hornby (1958) During the war years the MoS was based at Shell Mex House in The Strand, London. The Ministry of Supply also took over all army research establishments in 1939. The Ministry of Aircraft Production was abolished in 1946, and the MoS took over its responsibilities for aircraft, including the associated research establishments. In the same year, it also took on increased responsibilities for atomic weapons, including the H-bomb development programme. The Ministry of Supply was abolished in late 1959 and its responsibilities passed to the Ministry of Aviation, the War Of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Seeking
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of red light (the longest waves in the visible spectrum), so IR is invisible to the human eye. IR is generally (according to ISO, CIE) understood to include wavelengths from around to . IR is commonly divided between longer-wavelength thermal IR, emitted from terrestrial sources, and shorter-wavelength IR or near-IR, part of the solar spectrum. Longer IR wavelengths (30–100 μm) are sometimes included as part of the terahertz radiation band. Almost all black-body radiation from objects near room temperature is in the IR band. As a form of EMR, IR carries energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires emit invisible h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Aircraft Establishment
The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), before finally losing its identity in mergers with other institutions. The British Army Balloon Factory was established on Farnborough Common in the early 1900s. By 1912 it had come under civilian control and was the Royal Aircraft Factory (RAF) In 1918 it was renamed Royal Aircraft Establishment to prevent confusion with the newly created Royal Air Force. The first site was at Farnborough Airfield ("RAE Farnborough") in Hampshire to which was added a second site RAE Bedford (Bedfordshire) in 1946. On 1 May 1988 it was renamed the Royal Aerospace Establishment (RAE) before merging with other research entities to become part of the new Defence Research Agency in 1991. History In 1904–1906 the Army Balloon Factory, which was part of the A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
State Of The Art
The state of the art (SOTA or SotA, sometimes cutting edge, leading edge, or bleeding edge) refers to the highest level of general development, as of a device, technique, or scientific field achieved at a particular time. However, in some contexts it can also refer to a level of development reached at any particular time as a result of the common methodologies employed at the time. The term has been used since 1910, and has become both a common term in advertising and marketing, and a legally significant phrase with respect to both patent law and tort liability. In advertising, the phrase is often used to convey that a product is made with the best or latest available technology, but it has been noted that "the term 'state of the art' requires little proof on the part of advertisers", as it is considered mere puffery. The use of the term in patent law "does not connote even superiority, let alone the superlative quality the ad writers would have us ascribe to the term". Orig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
