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Operation Crossroads
Operation Crossroads was a pair of nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. They were the first nuclear weapon tests since Trinity in July 1945, and the first detonations of nuclear devices since the atomic bombing of Nagasaki on August 9, 1945. The purpose of the tests was to investigate the effect of nuclear weapons on warships. The Crossroads tests were the first of many nuclear tests held in the Marshall Islands, and the first to be publicly announced beforehand and observed by an invited audience, including a large press corps. They were conducted by Joint Army/Navy Task Force One, headed by Vice Admiral William H. P. Blandy rather than by the Manhattan Project, which had developed nuclear weapons during World War II. A fleet of 95 target ships was assembled in Bikini Lagoon and hit with two detonations of Fat Man plutonium implosion-type nuclear weapons of the kind dropped on Nagasaki in 1945, each with a yield of . The first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condensation Cloud
A transient condensation cloud, also called a Wilson cloud, is observable surrounding large explosions in humid air. When a nuclear weapon or a large amount of a conventional explosive is detonated in sufficiently humid air, the "negative phase" of the shock wave causes a rarefaction of the air surrounding the explosion, but not contained within it. This rarefaction results in a temporary cooling of that air, which causes a condensation of some of the water vapor contained in it. When the pressure and the temperature return to normal, the Wilson cloud dissipates. Mechanism Since heat does not leave the affected air mass, this change of pressure is adiabatic, with an associated change of temperature. In humid air, the drop in temperature in the most rarefied portion of the shock wave can bring the air temperature below its dew point, at which moisture condenses to form a visible cloud of microscopic water droplets. Since the pressure effect of the wave is reduced by its expans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fat Man
"Fat Man" (also known as Mark III) is the codename for the type of nuclear bomb the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the first being Little Boy, and its detonation marked the third nuclear explosion in history. It was built by scientists and engineers at Los Alamos Laboratory using plutonium from the Hanford Site, and it was dropped from the Boeing B-29 Superfortress '' Bockscar'' piloted by Major Charles Sweeney. The name Fat Man refers to the early design of the bomb because it had a wide, round shape. Fat Man was an implosion-type nuclear weapon with a solid plutonium core. The first of that type to be detonated was the Gadget in the Trinity nuclear test less than a month earlier on 16 July at the Alamogordo Bombing and Gunnery Range in New Mexico. Two more were detonated during the Operation Crossroads nuclear tests at Bikini Atoll in 1946, and some 120 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fishing
Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques include hand-gathering, spearing, netting, angling, shooting and trapping, as well as more destructive and often illegal techniques such as electrocution, blasting and poisoning. The term fishing broadly includes catching aquatic animals other than fish, such as crustaceans ( shrimp/ lobsters/crabs), shellfish, cephalopods (octopus/squid) and echinoderms ( starfish/ sea urchins). The term is not normally applied to harvesting fish raised in controlled cultivations ( fish farming). Nor is it normally applied to hunting aquatic mammals, where terms like whaling and sealing are used instead. Fishing has been an important part of human culture since hunter-gatherer times, and is one of the few food production activities that have persisted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subsistence Farming
Subsistence agriculture occurs when farmers grow food crops to meet the needs of themselves and their families on smallholdings. Subsistence agriculturalists target farm output for survival and for mostly local requirements, with little or no surplus. Planting decisions occur principally with an eye toward what the family will need during the coming year, and only secondarily toward market prices. Tony Waters, a professor of sociology, defines "subsistence peasants" as "people who grow what they eat, build their own houses, and live without regularly making purchases in the marketplace." Despite the self-sufficiency in subsistence farming, most subsistence farmers also participate in trade to some degree. Although their amount of trade as measured in cash is less than that of consumers in countries with modern complex markets, they use these markets mainly to obtain goods, not to generate income for food; these goods are typically not necessary for survival and may include sugar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rongerik Atoll
Rongerik Atoll or Rongdrik Atoll ( Marshallese: , ) is a coral atoll of 17 islands in the Pacific Ocean, and is located in the Ralik Chain of the Marshall Islands, approximately east of Bikini Atoll. Its total land area is only , but it encloses a lagoon of . History Rongerik Atoll was claimed by the German Empire along with the rest of the Marshall Islands in 1884. After World War I, the island came under the South Seas Mandate of the Empire of Japan, although the island was uninhabited. The island became part of the vast US Naval Base Marshall Islands. Following the end of World War II, it came under the control of the United States as part of the Trust Territory of the Pacific Islands until the independence of the Marshall Islands in 1986. It is most famous as the temporary location from March 7, 1946 through March 14, 1948 of the Bikini Atoll's indigenous population while the United States government conducted the Operation Crossroads nuclear tests. After months of food s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operation Wigwam
Operation Wigwam involved a single test of the Mark 90 "Betty" nuclear bomb. It was conducted between ''Operation Teapot'' and '' Project 56'' on May 14, 1955, about 500 miles (800 km) southwest of San Diego, California. 6,800 personnel aboard 30 ships were involved in ''Wigwam''. The purpose of ''Wigwam'' was to determine the vulnerability of submarines to deeply detonated nuclear weapons, and to evaluate the feasibility of using such weapons in a combat situation. The task force commander, Admiral John Sylvester, was embarked on the task force flagship . ''Wigwam'' was the first atomic test in the deep ocean, and it remains the only test that has been conducted in water deeper than . Detonation layout and test The test device was suspended to a depth of by cable attached to a barge. A tow line connected the Cherokee-class fleet tug, , to the shot barge. Suspended from the tow lines of other tugs were three miniature unmanned target submarines designated "SQUAWS", ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 allies or partner nations of the United States as of 2015. It has the highest combined battle fleet tonnage (4,635,628 tonnes as of 2019) and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the United States Navy is the third largest of the United States military service branches in terms of personnel. It has 290 deployable combat vessels and more than 2,623 operational aircraft . The United States Navy traces its origins to the Continental Navy, which was established during the American Revo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aim Point
{{Unreferenced, date=April 2007 In field artillery, the accuracy of indirect fire depends on the use of aiming points. In air force terminology the aiming point (or A.P.) refers to holding the intersection of the cross hairs on a bombsight when fixed at a specific target. An indirect fire aiming point provides a point of angular reference to aim a gun in the required horizontal direction – azimuth. Until the 1980s aiming points were essential for indirect fire artillery. They are also used by mortars and machine guns firing indirectly. An essential requirement of an aiming point is that it be at a sufficient distance from the gun using it. The reason for this is that, while firing, guns, particularly towed guns, move back a short distance – perhaps a foot, as their spades embed and may move more in soft ground. When they traverse their barrels their sights also move because they are not at the point of pivot. All this means that if the aiming point is too close then the ang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
509th Bombardment Group
5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. It has attained significance throughout history in part because typical humans have five digits on each hand. In mathematics 5 is the third smallest prime number, and the second super-prime. It is the first safe prime, the first good prime, the first balanced prime, and the first of three known Wilson primes. Five is the second Fermat prime and the third Mersenne prime exponent, as well as the third Catalan number, and the third Sophie Germain prime. Notably, 5 is equal to the sum of the ''only'' consecutive primes, 2 + 3, and is the only number that is part of more than one pair of twin primes, ( 3, 5) and (5, 7). It is also a sexy prime with the fifth prime number and first prime repunit, 11. Five is the third factorial prime, an alternating factorial, and an Eisenstein prime with no imaginary part and real part of the form 3p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big Stink (B-29)
''Big Stink'' – later renamed ''Dave's Dream'' – was a United States Army Air Forces Boeing B-29-40-MO Superfortress bomber ( Victor number 90) that participated in the atomic bomb attack on Nagasaki, Japan on August 9, 1945. Assigned to the 393d Bomb Squadron, 509th Composite Group, it was used as a camera plane in support of the bomb-carrying B-29 '' Bockscar'' to photograph the explosion and effects of the bomb, and also to carry scientific observers. The mission was flown by crew C-14 but with Group Operations Officer Major James I. Hopkins, Jr., as the aircraft commander. Victor 90 left without one of the support members when Major Hopkins ordered Robert Serber of Project Alberta to leave the plane – reportedly after the B-29 had already taxied onto the runway – because the scientist had forgotten his parachute. Since Serber was the only crew member who knew how to operate the high-speed camera, Hopkins had to be instructed by radio from Tinian o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeing B-29 Superfortress
The Boeing B-29 Superfortress is an American four-engined propeller-driven heavy bomber, designed by Boeing and flown primarily by the United States during World War II and the Korean War. Named in allusion to its predecessor, the B-17 Flying Fortress, the Superfortress was designed for high-altitude strategic bombing, but also excelled in low-altitude night incendiary bombing, and in dropping naval mines to blockade Japan. B-29s dropped the atomic bombs on Hiroshima and Nagasaki, the only aircraft ever to drop nuclear weapons in combat. One of the largest aircraft of World War II, the B-29 was designed with state-of-the-art technology, which included a pressurized cabin, dual-wheeled tricycle landing gear, and an analog computer-controlled fire-control system that allowed one gunner and a fire-control officer to direct four remote machine gun turrets. The $3 billion cost of design and production (equivalent to $ billion today), far exceeding the $1.9 b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilda
''Gilda'' is a 1946 American film noir directed by Charles Vidor and starring Rita Hayworth in her signature role and Glenn Ford. The film is known for cinematographer Rudolph Maté's lush photography, costume designer Jean Louis's wardrobe for Hayworth (particularly for the dance numbers), and choreographer Jack Cole's staging of "Put the Blame on Mame" and "Amado Mio", sung by Anita Ellis. Over the years ''Gilda'' has gained cult classic status. In 2013, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically or aesthetically significant". Plot Johnny Farrell, an American newly arrived in Buenos Aires, Argentina, wins a lot of money cheating at craps. He is rescued from a robbery attempt by a complete stranger, Ballin Mundson. Mundson tells him about an illegal high-class casino, but warns him not to cheat there. Farrell ignores his advice, wins at blackjack, and is taken to see the cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
