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Ivigtût
Ivittuut (formerly, Ivigtût) ( Kalaallisut: "Grassy Place") is an abandoned mining town near Cape Desolation in southwestern Greenland, in the modern Sermersooq municipality on the ruins of the former Norse Middle Settlement. Ivittuut is one of the few places in the world so far discovered to have naturally occurring cryolite (Na3AlF6, sodium aluminum fluoride), an important agent in modern aluminum extraction. History The area was settled by about twenty farms of Norsemen, a district called the "Middle Settlement" by modern archaeologists from its placement between the larger Western and Eastern Settlements. It is the smallest and least well known of the three, and no written records of its residents survive, for which reasons it is believed to have been established last (and abandoned first) of the three. Investigations show a presence after 985 and with occupation continuing up to at least the 14th century. The town's cryolite deposit was discovered in 1799, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hexafluoroaluminate
Sodium hexafluoroaluminate is an inorganic compound with formula Na3 Al F6. This white solid, discovered in 1799 by Peder Christian Abildgaard (1740–1801), occurs naturally as the mineral cryolite and is used extensively in the industrial production of aluminium. The compound is the sodium (Na+) salt of the hexafluoroaluminate (AlF63−) ion. Production Most cryolite is manufactured by a variety of related pathways. One route entails combining sodium aluminate and hydrofluoric acid: :Na3Al(OH)6 + 6 HF → Na3AlF6 + 6 H2O Other routes include: : : Often the hexafluoroaluminic acid, which is recovered from phosphate mining, is the precursor in a two-step process beginning with neutralization with ammonia to give ammonium hexafluoroaluminate: :H3AlF6 + 3NH3 → (NH4)3AlF6 :(NH4)3AlF6 + 3NaOH → Na3AlF6 + 3NH3 + 3H2O The mineral form of sodium hexafluoroaluminate, which is called cryolite, was mined at Ivigtût on the west coast of Greenland until the depo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kriolit Mine Og Handels Selskabet
Ivittuut (formerly, Ivigtût) ( Kalaallisut: "Grassy Place") is an abandoned mining town near Cape Desolation in southwestern Greenland, in the modern Sermersooq municipality on the ruins of the former Norse Middle Settlement. Ivittuut is one of the few places in the world so far discovered to have naturally occurring cryolite (Na3AlF6, sodium aluminum fluoride), an important agent in modern aluminum extraction. History The area was settled by about twenty farms of Norsemen, a district called the "Middle Settlement" by modern archaeologists from its placement between the larger Western and Eastern Settlements. It is the smallest and least well known of the three, and no written records of its residents survive, for which reasons it is believed to have been established last (and abandoned first) of the three. Investigations show a presence after 985 and with occupation continuing up to at least the 14th century. The town's cryolite deposit was discovered in 1799, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Countries Of The Kingdom Of Denmark
The Danish Realm, officially the Kingdom of Denmark, or simply Denmark, is a sovereign state consisting of a collection of constituent territories united by the Constitutional Act, which applies to the entire territory. It consists of metropolitan Denmark—the kingdom's territory in continental Europe and sometimes called "Denmark proper"—and the realm's two autonomous (but not sovereign) regions: the Faroe Islands in the North Atlantic and Greenland in North America.Administrative divisions – Denmark . Access date: 14 April 2012 The relationship between the three parts of the kingdom is k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentiferous Galena
Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite. As a pure specimen held in the hand, under standard temperature and pressure, galena is insoluble in water and so is almost non-toxic. Handling galena under these specific conditions (such as in a museum or as part of geology instruction) poses practically no risk; however, as lead(II) sulfide is reasonably reactive in a variety of environments, it can be highly toxic if swallowed or inhaled, particularly under prolonged or repeated exposure. Occurrence Galena is the main ore of lead, used since ancient times, since lead can be smelted from galena in an ordinary wood fire. Galena typically is found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subarctic
The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of hemiboreal regions and covering much of Alaska, Canada, Iceland, the north of Fennoscandia, Northwestern Russia, Siberia, and the Cairngorms. Generally, subarctic regions fall between 50°N and 70°N latitude, depending on local climates. Precipitation is usually low, and vegetation is characteristic of the taiga. Daylight at these latitudes is quite extreme between summer and winter due to its high latitude. Near the summer solstice for instance, subarctic regions can experience an all-night period of either civil, nautical, or astronomical twilight (or in the northern reaches full daylight), since the sun never dips more than 18 degrees below the horizon. Noctilucent clouds are best observed within this range of latitude. Climate and soils Subarctic temperatures are above for at least one and at most three months of the year. Precipitation tends to be low due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Köppen Climate Classification
The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (temperate), ''D'' (continental), and ''E'' (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the ''E'' group are assigned a seasonal precipitation subgroup (the second letter). For example, ''Af'' indicates a tropical rainforest climate. The system assigns a temperature subgroup for all groups other than those in the ''A'' group, indicated by the third letter for climates in ''B'', ''C'', ''D'', and the second letter for climates in ''E''. Other examples include: ''Cfb'' indicating an oceanic climate with warm summers as indicated by the ending ''b.'', while ''Dwb'' indicates a semi-Monsoon continental climate, monsoonal continental climate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra
In physical geography, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic, Antarctic. Tundra vegetation is composed of dwarf shrubs, Cyperaceae, sedges, Poaceae, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink. As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-contained greenhouse gases into the atmosphere, creating Climate change feedback, a feedback cycle t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biplane
A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a biplane wing structure has a structural advantage over a monoplane, it produces more drag than a monoplane wing. Improved structural techniques, better materials and higher speeds made the biplane configuration obsolete for most purposes by the late 1930s. Biplanes offer several advantages over conventional cantilever monoplane designs: they permit lighter wing structures, low wing loading and smaller span for a given wing area. However, interference between the airflow over each wing increases drag substantially, and biplanes generally need extensive bracing, which causes additional drag. Biplanes are distinguished from tandem wing arrangements, where the wings are placed forward and aft, instead of above and below. The term is als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Aerial Circumnavigation
The first aerial circumnavigation of the world was completed in 1924 by four aviators from an eight-man team of the United States Army Air Service, the precursor of the United States Air Force. The 175-day journey from April to September covered over . The team generally traveled east to west, around the northern Pacific Rim, through to South Asia and Europe and back to Seattle's Sand Point Airfield in the United States. Airmen Lowell Smith, Lowell H. Smith and Leslie P. Arnold, and Erik H. Nelson and John Richard Harding, John Harding Jr. made the trip in two single-engined open-cockpit Douglas World Cruisers (DWC) configured as floatplanes for most of the journey. Lead aircraft ''Chicago,'' and the ''New Orleans'' completed the expedition. Four more flyers in two additional DWC began the journey but their aircraft crashed or were forced down. All airmen survived. They were awarded the Distinguished Service Medal (U.S. Army), Distinguished Service Medal, and the flight won the Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Greenland
Air Greenland Aktieselskab, A/S (formerly named Grønlandsfly and Greenlandair) is the flag carrier of Greenland, owned by the Naalakkersuisut, Greenlandic Government. It operates a fleet of 28 aircraft, including a single Airbus A330-800 airliner used for transatlantic flight, transatlantic and charter flights, 9 fixed-wing aircraft primarily serving the domestic network, and 18 helicopters feeding passengers from the smaller communities into the domestic airport network. Flights to heliports in the remote settlements are operated on contract with the government of Greenland. Its domestic and international hub is at Nuuk Airport. Besides running scheduled services and government-contracted flights to most villages in the country, the airline also supports remote research stations, provides charter services for tourism in Greenland, tourists and Greenland's Arctic petroleum exploration, energy and economy of Greenland#Mining, mineral-resource industries and permits Medical evacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks in World War II, Tanks and Air warfare of World War II, aircraft played major roles, enabling the strategic bombing of cities and delivery of the Atomic bombings of Hiroshima and Nagasaki, first and only nuclear weapons ever used in war. World War II is the List of wars by death toll, deadliest conflict in history, causing World War II casualties, the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Allied-occupied Germany, Germany, Allied-occupied Austria, Austria, Occupation of Japan, Japan, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Occupation Of Greenland
The fall of Denmark in April 1940 left the Danish colony of Greenland an unoccupied territory of an occupied nation, under the possibility of seizure by the United Kingdom, United States or Canada. To forestall this, the United States acted to guarantee Greenland's position. On 9 April 1941, Greenland became a ''de facto'' United States protectorate. With the entrance of the United States into the war in December 1941, Greenland became a combatant. From 1941 until 1945, the United States established numerous and extensive facilities for air and sea traffic in Greenland, as well as radio beacons, radio stations, weather stations, ports, depots, artillery posts, and search-and-rescue stations. The United States Coast Guard also provided a considerable portion of civilian resupply along both coasts. Economically, Greenland traded successfully with the United States, Canada and Portugal, which, supplemented by the cryolite exports, caused a reanimation and permanent realignment of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
