|
Sonic Boom
A sonic boom is a sound associated with shock waves created when an object travels through the air faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding similar to an explosion or a thunderclap to the human ear. The crack of a supersonic bullet passing overhead or the crack of a bullwhip are examples of a small sonic boom. Sonic booms due to large supersonic aircraft can be particularly loud and startling, tend to awaken people, and may cause minor damage to some structures. This led to the prohibition of routine supersonic flight overland. Although sonic booms cannot be completely prevented, research suggests that with careful shaping of the vehicle, the nuisance due to sonic booms may be reduced to the point that overland supersonic flight may become a feasible option. A sonic boom does not occur only at the moment an object crosses the sound barrier and neither is it heard in all directions emanating from the supersonic objec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oklahoma City Sonic Boom Tests
The Oklahoma City sonic boom tests, also known as Operation Bongo II, refer to a controversial experiment, organized by the Federal Aviation Administration (FAA), in which 1,253 sonic booms were generated over Oklahoma City, Oklahoma, over a period of six months starting in February 1964. The experiment was intended to quantify the effects of transcontinental supersonic transport (SST) aircraft on a city, to measure the booms' effect on structures and public attitude, and to develop standards for boom prediction and insurance data. Oklahoma City's population was perceived to be relatively tolerant of such an experiment, as it had an economic dependency on the nearby Mike Monroney Aeronautical Center and Tinker Air Force Base; and, in fact, the local Chamber of Commerce threw a celebratory dinner when Oklahoma was selected. Despite this the testing was stopped early, in the wake of damage complaints, and although the final report said that "the overwhelming majority felt they c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cone
In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the '' apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, or lines connecting a common point, the apex, to all of the points on a base. In the case of line segments, the cone does not extend beyond the base, while in the case of half-lines, it extends infinitely far. In the case of lines, the cone extends infinitely far in both directions from the apex, in which case it is sometimes called a ''double cone''. Each of the two halves of a double cone split at the apex is called a ''nappe''. Depending on the author, the base may be restricted to a circle, any one-dimensional quadratic form in the plane, any closed one-dimensional figure, or any of the above plus all the enclosed points. If the enclosed points are included in the base, the cone is a solid object; otherwise it is an open surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lockheed SR-71 Blackbird
The Lockheed SR-71 "Blackbird" is a retired long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft developed and manufactured by the American aerospace company Lockheed Corporation. Its nicknames include " Blackbird" and " Habu". The SR-71 was developed in the 1960s as a black project by Lockheed's Skunk Works division. American aerospace engineer Clarence "Kelly" Johnson was responsible for many of the SR-71's innovative concepts. Its shape was based on the Lockheed A-12, a pioneer in stealth technology with its reduced radar cross section, but the SR-71 was longer and heavier to carry more fuel and a crew of two in tandem cockpits. The SR-71 was revealed to the public in July 1964 and entered service in the United States Air Force (USAF) in January 1966. During missions, the SR-71 operated at high speeds and altitudes (Mach 3.2 at ), allowing it to evade or outrace threats. If a surface-to-air missile launch was detected, the standard evasive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling. is the pressure relative to the ambient pressure. Various #Units, units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the International System of Units, SI unit of pressure, the Pascal (unit), pascal (Pa), for example, is one newton (unit), newton per square metre (N/m2); similarly, the Pound (force), pound-force per square inch (Pound per square inch, psi, symbol lbf/in2) is the traditional unit of pressure in the imperial units, imperial and United States customary units, US customary systems. Pressure ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supersonic Speed
Supersonic speed is the speed of an object that exceeds the speed of sound (Mach number, Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times the speed of sound (Mach 5) are often referred to as hypersonic. Flights during which only some parts of the air surrounding an object, such as the ends of rotor blades, reach supersonic speeds are called transonic. This occurs typically somewhere between Mach 0.8 and Mach 1.2. Sounds are traveling vibrations in the form of pressure waves in an elastic medium. Objects move at supersonic speed when the objects move faster than the speed at which sound propagates through the medium. In gases, sound travels longitudinally at different speeds, mostly depending on the molecular mass and temperature of the gas, and pressure has little effect. Since air temperature and composition varies significantly with altitude, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NATO
The North Atlantic Treaty Organization (NATO ; , OTAN), also called the North Atlantic Alliance, is an intergovernmental organization, intergovernmental Transnationalism, transnational military alliance of 32 Member states of NATO, member states—30 European and 2 North American. Established in the aftermath of World War II, the organization implements the North Atlantic Treaty, signed in Washington, D.C., on 4 April 1949. NATO is a collective security system: its independent member states agree to defend each other against attacks by third parties. During the Cold War, NATO operated as a check on the threat posed by the Soviet Union. The alliance remained in place after the dissolution of the Soviet Union and the Warsaw Pact, and has been involved in military operations in the Balkans, the Middle East, South Asia, and Africa. The organization's motto is . The organization's strategic concepts include Deterrence theory, deterrence. NATO headquarters, NATO's main headquarter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Motion
Ground motion is the movement of the Earth’s surface from earthquakes or explosions. Ground motion is produced by seismic waves that are generated by sudden slip on a fault or sudden pressure at the explosive source and travel through the Earth and along its surface. This can be due to natural events, such as earthquakes and volcanic eruptions, or human activities, such as the detonation of nuclear weapons. There are two main types of seismic waves: body waves and surface waves. Body waves travel through the interior of the Earth, while surface waves travel along the Earth's surface. Ground motion is typically caused by surface waves, which are the most destructive type of seismic waves. Ground motion is measured using a seismometer A seismometer is an instrument that responds to ground displacement and shaking such as caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F-4 Phantom II
The McDonnell Douglas F-4 Phantom II is an American tandem two-seat, twin-engine, all-weather, long-range supersonic jet interceptor and fighter-bomber that was developed by McDonnell Aircraft for the United States Navy.Swanborough and Bowers 1976, p. 301. It entered service with the Navy in 1961, then was adopted by the United States Marine Corps, and the United States Air Force, and within a few years became a major part of their air arms. A total of 5,195 Phantoms were built from 1958 to 1981, making it the most-produced American supersonic military aircraft in history and a signature combat aircraft of the Cold War."F-4 Phantoms Phabulous 40th" Boeing. Retrieved : 27 November 2012.. The Phantom is a large fighter with a top spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal (unit)
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is an SI coherent derived unit defined as one newton per square metre (N/m2). It is also equivalent to 10 barye (10 Ba) in the CGS system. Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa), which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa), which is equal to one centibar. The unit of measurement called '' standard atmosphere (atm)'' is defined as . Meteorological observations typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization, thus a standard atmosphere (atm) or typical sea-level air pressure is about 1013 hPa. Reports in the United States typically use inches of mercury or millibars (hectopascals). In Cana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Carpet
A red carpet is traditionally used to mark the route taken by heads of state on ceremonial and formal occasions, and has in recent decades been extended to use by Very Important Person, VIPs and celebrity, celebrities at formal events. History The earliest known reference to walking a red carpet in literature is in the play ''The Oresteia, Agamemnon'' by Aeschylus, written in 458 BC. When the title character returns from Troy, he is greeted by his wife Clytemnestra who offers him a red path to walk upon: Agamemnon, knowing that only Greek mythology, gods walk on such luxury, responds with trepidation: Oriental carpets in Renaissance painting, Renaissance paintings often show rugs and carpets in oriental patterns, with red often the main background colour, laid on the steps to a throne, or on a dais where rulers or sacred figures are placed. A red carpet was rolled out to welcome the arrival of United States president James Monroe in South Carolina in 1821. In 1902, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overpressure
Overpressure (or blast overpressure) is the pressure caused by a shock wave over and above normal atmospheric pressure. The shock wave may be caused by sonic boom or by explosion An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated ..., and the resulting overpressure receives particular attention when measuring the effects of nuclear weapons or thermobaric bombs. Effects According to an article in the journal '' Toxicological Sciences'', Blast overpressure (BOP), also known as high energy impulse noise, is a damaging outcome of explosive detonations and firing of weapons. Exposure to BOP shock waves alone results in injury predominantly to the hollow organ systems such as auditory, respiratory, and gastrointestinal systems. An EOD suit worn by bomb disposal experts can protect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
