|
Upshot-Knothole Grable
Upshot–Knothole ''Grable'' was a nuclear weapons test conducted by the United States as part of Operation Upshot–Knothole. Detonation of the associated nuclear weapon occurred 19 seconds after its deployment at 8:30am PDT (1530 UTC) on May 25, 1953, in Area 5 of the Nevada Test Site. Nuclear weapons test The codename ''Grable'' was chosen because the letter ''Grable'' is phonetic for G, as in "gun", since the warhead was a gun-type fission weapon. As a shell, or artillery-fired atomic projectile (AFAP), the device was the first of its kind. The test remains the only nuclear artillery shell ever actually fired in the U.S. nuclear weapons test program. ''Grable'' was the second of only four gun-type warheads ever detonated (the first was Little Boy, the weapon used against Hiroshima, the last two were test firings of the W33; all other atomic weapons were implosion-type weapons). The shell, designated a Mark 9 nuclear weapon, had a diameter of 280 mm (11.02 in), was 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mushroom Cloud
A mushroom cloud is a distinctive mushroom-shaped flammagenitus cloud of debris, smoke and usually condensed water vapor resulting from a large explosion. The effect is most commonly associated with a nuclear explosion, but any sufficiently energetic detonation or deflagration will produce the same effect. They can be caused by powerful conventional weapons, like thermobaric weapons, including the ATBIP and GBU-43/B Massive Ordnance Air Blast. Some volcanic eruptions and impact events can produce natural mushroom clouds. Mushroom clouds result from the sudden formation of a large volume of lower-density gases at any altitude, causing a Rayleigh–Taylor instability. The buoyant mass of gas rises rapidly, resulting in turbulent vortices curling downward around its edges, forming a temporary vortex ring that draws up a central column, possibly with smoke, debris, condensed water vapor, or a combination of these, to form the "mushroom stem". The mass of gas plus entrained moist ai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Little Boy
"Little Boy" was the type of atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped by the Boeing B-29 Superfortress ''Enola Gay'' piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces and Captain Robert A. Lewis. It exploded with an energy of approximately and caused widespread death and destruction throughout the city. The Hiroshima bombing was the second man-made nuclear explosion in history, after the Trinity nuclear test. Little Boy was developed by Lieutenant Commander Francis Birch (geophysicist), Francis Birch's group at the Manhattan Project's Los Alamos Laboratory during World War II, a reworking of their unsuccessful Thin Man (nuclear bomb), Thin Man nuclear bomb. Like Thin Man, it was a gun-type fission weapon, but it derived its explosive power from the nuclear fission of uranium-235, where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Warfare
Nuclear warfare, also known as atomic warfare, is a theoretical military conflict or prepared political strategy that deploys nuclear weaponry. Nuclear weapons are weapons of mass destruction; in contrast to conventional warfare, nuclear warfare can produce destruction in a much shorter time and can have a long-lasting radiological result. A major nuclear exchange would likely have long-term effects, primarily from the fallout released, and could also lead to secondary effects, such as " nuclear winter", nuclear famine and societal collapse. A global thermonuclear war with Cold War-era stockpiles, or even with the current smaller stockpiles, may lead to various scenarios including the extinction of the human race. To date, the only use of nuclear weapons in armed conflict occurred in 1945 with the American atomic bombings of Hiroshima and Nagasaki. On August 6, 1945, a uranium gun-type device (code name "Little Boy") was detonated over the Japanese city of Hiroshi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precursor (physics)
Precursors are characteristic wave patterns caused by dispersion of an impulse's frequency components as it propagates through a medium. Classically, precursors precede the main signal, although in certain situations they may also follow it. Precursor phenomena exist for all types of waves, as their appearance is only predicated on the prominence of dispersion effects in a given mode of wave propagation. This non-specificity has been confirmed by the observation of precursor patterns in different types of electromagnetic radiation (microwaves, visible light, and terahertz radiation) as well as in fluid surface waves and seismic waves. History Precursors were first theoretically predicted in 1914 by Arnold Sommerfeld for the case of electromagnetic radiation propagating through a neutral dielectric in a region of normal dispersion.See L. Brillouin, ''Wave Propagation and Group Velocity'' (Academic Press, New York, NY, 1960), Ch. 1. Sommerfeld's work was expanded in the following ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Burst
An air burst or airburst is the detonation of an explosive device such as an anti-personnel artillery shell or a nuclear weapon in the air instead of on contact with the ground or target. The principal military advantage of an air burst over a ground burst is that the energy from the explosion (as well as any shell fragments) is distributed more evenly over a wider area; however, the peak energy is lower at ground zero. History Air burst artillery has a long history. The shrapnel shell was invented by Henry Shrapnel of the British Army in about 1780 to increase the effectiveness of canister shot. It was widely used by the time of the War of 1812 and stayed in use until it was superseded during the First World War. Modern shells, though sometimes called "shrapnel shells", actually produce fragments and splinters, not shrapnel. Air bursts were used in the First World War to shower enemy positions and men with shrapnel balls to kill the largest possible number with a sing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frenchman Flat
Frenchman Flat is a hydrographic basin in the Nevada National Security Site south of Yucca Flat and north of Mercury, Nevada. The flat was used as an American nuclear test site and has a dry lake bed (Frenchman Lake) that was used as a 1950s airstrip before it was chosen after the start of the Korean War for the Nevada Proving Grounds. Nellis Air Force Base land was transferred to the Atomic Energy Commission on which Site Mercury was constructed on the flat for supporting American nuclear explosive tests. The 1951 Operation Ranger "Able" test (ground zero at UTM Coordinates 923758 on the flat) was the first continental US nuclear detonation after the 1945 Trinity test, and Frenchman Flat also had the only detonation of an American artillery-fired nuclear projectile in the 1953 Upshot-Knothole Grable test using the M65 Atomic Cannon. Area 5 Area 5 consists of of the southeastern portion of NTS, north of the town of Mercury, and includes the Area 5 Radioactive Waste Man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Ton
The short ton (symbol tn) is a measurement unit equal to . It is commonly used in the United States, where it is known simply as a ton, although the term is ambiguous, the single word being variously used for short, long, and metric ton. The various tons are defined as units of mass.Butcher, Crown and Gentry, NIST Special Publication 1038, The International System of Units (SI) – Conversion Factors for General Use, 2006 They are sometimes used as units of weight, the force exerted by a mass at standard gravity (e.g., short ton-force). One short ton exerts a weight at one standard gravity of 2,000 pound-force (lbf). United States In the United States, a short ton is usually known simply as a "ton", without distinguishing it from the tonne (), known there as the "metric ton", or the long ton also known as the "imperial ton" (). There are, however, some U.S. applications where unspecified ''tons'' normally mean long tons (for example, naval ships) or metric tons (world grain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United States customary units), and the long ton ( British imperial units). It is equivalent to approximately 2204.6 pounds, 1.102 short tons, and 0.984 long tons. The official SI unit is the megagram (symbol: Mg), a less common way to express the same mass. Symbol and abbreviations The BIPM symbol for the tonne is t, adopted at the same time as the unit in 1879.Table 6 . BIPM. Retrieved on 2011-07-10. Its use is also official for the metric ton in the United States, having been adopted by the United States |
W9 (nuclear Warhead)
The W9 was an American nuclear artillery shell fired from a special howitzer. It was produced starting in 1952 and all were retired by 1957, being superseded by the W19. Description The W9 was in diameter, long, and weighed . It had an explosive yield of . The W9 was a gun-type nuclear weapon, using around of highly enriched uranium in one large rings assembly and one smaller ''bullet'', which was fired down a tube by conventional explosives into the rings assembly to achieve critical mass and detonate the weapon. The W9 units which were retired in 1957 were recycled into lower yield T-4 Atomic Demolition Munitions. These were the first (semi) man-portable nuclear weapons. Tests The W9 is only the second gun-type nuclear weapon known to have been detonated; the first was the Little Boy nuclear weapon used in World War II. The W9 artillery shell was test fired once, fired from the "Atomic Annie" M65 Atomic Cannon, in ''Upshot-Knothole Grable'' on May 25, 1953 at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
