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Kryolitselskabet Øresund
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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Countries Of The Kingdom Of Denmark
The Danish Realm ( da, Danmarks Rige; fo, Danmarkar Ríki; kl, Danmarkip Naalagaaffik), officially the Kingdom of Denmark (; ; ), is a sovereign state located in Northern Europe and Northern North America. It consists of metropolitan Denmark, the kingdom's territory in continental Europe and sometimes called "Denmark proper" ( da, egentlige Danmark, links=no), and the realm's two autonomous regions: the Faroe Islands and Greenland.Administrative divisions – Denmark . Access date: 14 April 2012 The relationship between the three parts of the Kingdom is also known as The unity of the Realm (; [...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. 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 in hydrothermal veins in association with sphalerite, marcasite, chalcopyrite, cerussite, anglesite, dolomite, calcite, quartz, barite, and fluorite. It is also found in association with sphalerite in low-temperature lead-zinc deposits within limestone beds. Minor amounts are found in contact metamorphic zones, in pegmatites, and disseminated in sedimentary rock. In some deposits the galena contains up to 0.5% silver, a byproduct that far ... [...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 humid continental regions and covering much of Alaska, Canada, Iceland, the north of Scandinavia, 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), but without true night, 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 du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Köppen Climate Classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist Rudolf Geiger (1894–1981) introduced some changes to the classification system, which is thus sometimes called the Köppen–Geiger climate classification system. The Köppen climate classification divides climates into five main climate groups, with each group being divided based on seasonal precipitation and temperature patterns. 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'' indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mountain tract". There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra. Tundra vegetation is composed of dwarf shrubs, sedges, 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 g ... [...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 also ... [...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 covered over . The team generally traveled east to west, around the northern-Pacific Rim, through to South Asia and Europe and back to the United States. Airmen Lowell H. Smith and Leslie P. Arnold, and Erik H. Nelson and John Harding Jr. made the trip in two single-engined open-cockpit Douglas World Cruisers (DWC) configured as floatplanes for most of the journey. Four more flyers in two additional DWC began the journey but their aircraft crashed or were forced down. All airmen survived. In 1930, Australian Charles Kingsford Smith with a team of three others completed the first circumnavigation of the world by flight traversing both hemispheres, including the first trans-Pacific flight, from the US to Australia, in 1928. Kingsford Smith flew a Fokker F.VIIb/3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Greenland
Air Greenland A/S (formerly named Grønlandsfly), also known as Greenlandair, is the flag carrier airline of Greenland, owned by the Greenlandic Government. It operates a fleet of 32 aircraft, including 1 airliner used for transatlantic and charter flights, 8 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. 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 tourists and Greenland's energy and mineral-resource industries and permits medivac during emergencies. Air Greenland has seven subsidiaries, an airline, hotels, tour operators, and a travel agency specialised in Greenlandic tourism. History Founded in 1960 as ''Grønlandsfly'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, mas ... [...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. 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 the island's economy. Neutrality Before the war, Greenland was a tightly cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bauxite
Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite (FeO(OH)) and haematite (Fe2O3), the aluminium clay mineral kaolinite (Al2Si2O5(OH)4) and small amounts of anatase (TiO2) and ilmenite (FeTiO3 or FeO.TiO2). Bauxite appears dull in luster and is reddish-brown, white, or tan. In 1821, the French geologist Pierre Berthier discovered bauxite near the village of Les Baux in Provence, southern France. Formation Numerous classification schemes have been proposed for bauxite but, , there was no consensus. Vadász (1951) distinguished lateritic bauxites (silicate bauxites) from karst bauxite ores (carbonate bauxites): * The carbonate bauxites occur predominantly in Europe, Guyana, Suriname, and Jamaica above carbonate rocks (limestone and do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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