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Sand Dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes, with little or no vegetation, are called '' ergs'' or ''sand seas''. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter ''slip face'' in the lee side. The valley or trough between dunes is called a ''dune slack''. Dunes are most common in desert environments, where the lack of moisture hinders the growth of vegetation that would otherwise interfere with the development of dunes. However, sand deposits are not restricted to deserts, and dunes are also found along sea shores, along streams in semiarid climates, in areas of glacial outwash, and in other areas where poorly cemented san ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Outback - Australische Outback
Australian(s) may refer to: Australia * Australia, a country * Australians, citizens of the Commonwealth of Australia ** European Australians ** Anglo-Celtic Australians, Australians descended principally from British colonists ** Aboriginal Australians, indigenous peoples of Australia as identified and defined within Australian law * Australia (continent) ** Indigenous Australians * Australian English, the dialect of the English language spoken in Australia * Australian Aboriginal languages * ''The Australian'', a newspaper * Australiana, things of Australian origins Other uses * Australian (horse), a racehorse * Australian, British Columbia, an unincorporated community in Canada See also * The Australian (other) * Australia (other) * * * Austrian (other) {{disambiguation Language and nationality disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Dutch
Middle Dutch is a collective name for a number of closely related West Germanic dialects whose ancestor was Old Dutch. It was spoken and written between 1150 and 1500. Until the advent of Modern Dutch after 1500 or , there was no overarching standard language, but all dialects were mutually intelligible. During that period, a rich Medieval Dutch literature developed, which had not yet existed during Old Dutch. The various literary works of the time are often very readable for speakers of Modern Dutch since Dutch is a rather conservative language. Phonology Differences with Old Dutch Several phonological changes occurred leading up to the Middle Dutch period. * Earlier Old Dutch , , merge into already in Old Dutch. * Voiceless fricatives become voiced syllable-initially: > , > (merging with from Proto-Germanic ), > . (10th or 11th century) * > * > or . The outcome is dialect-specific, with found in more western dialects and further east. This results in later pairs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seif Dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes, with little or no vegetation, are called '' ergs'' or ''sand seas''. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter ''slip face'' in the lee side. The valley or trough between dunes is called a ''dune slack''. Dunes are most common in desert environments, where the lack of moisture hinders the growth of vegetation that would otherwise interfere with the development of dunes. However, sand deposits are not restricted to deserts, and dunes are also found along sea shores, along streams in semiarid climates, in areas of glacial outwash, and in other areas where poorly cemented san ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taklamakan Desert
The Taklamakan Desert ( ) is a desert in northwest China's Xinjiang region. Located inside the Tarim Basin in Southern Xinjiang, it is bounded by the Kunlun Mountains to the south, the Pamir Mountains to the west, the Tian Shan range to the north, and the Gobi Desert to the east. Etymology While most researchers agree on being the Persian word for "place", etymology of ''Takla'' is less clear. The word may be a Uyghur borrowing of the Persian , "to leave alone/out/behind, relinquish, abandon" + ''makan''. Another plausible explanation suggests it is derived from Turki ''taqlar makan'', describing "the place of ruins". Chinese scholars Wang Guowei and Huang Wenbi linked the name to the Tocharians, a historical people of the Tarim Basin, making the meaning of "Taklamakan" similar to "Tocharistan". According to Uyghur researcher Turdi Mettursun Kara, the name Taklamakan comes from the expression Terk-i Mekan. The name is first mentioned as Terk-i Makan (ترك مكان ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egypt
Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northern coast of Egypt, the north, the Gaza Strip of Palestine and Israel to Egypt–Israel barrier, the northeast, the Red Sea to the east, Sudan to Egypt–Sudan border, the south, and Libya to Egypt–Libya border, the west; the Gulf of Aqaba in the northeast separates Egypt from Jordan and Saudi Arabia. Cairo is the capital, list of cities and towns in Egypt, largest city, and leading cultural center, while Alexandria is the second-largest city and an important hub of industry and tourism. With over 109 million inhabitants, Egypt is the List of African countries by population, third-most populous country in Africa and List of countries and dependencies by population, 15th-most populated in the world. Egypt has one of the longest histories o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Desert (Egypt)
In Egypt, the Western Desert is an area of the Sahara that lies west of the river Nile, up to the Egypt–Libya border, Libyan border, and south from the Mediterranean Sea to the Egypt–Sudan border, border with Sudan. It is named in contrast to the Eastern Desert which extends east from the Nile to the Red Sea. The Western Desert is mostly Reg (landform), rocky desert, though an area of Erg (landform), sandy desert, known as the Great Sand Sea, lies to the west against the Libyan border. The desert covers an area of which is two-thirds of the land area of the country. Its highest elevation is in the Gilf Kebir plateau to the far south-west of the country, on the Egypt-Sudan-Libya border. The Western Desert is barren and uninhabited save for a chain of oases which extend in an arc from Siwa Oasis, Siwa, in the north-west, to Kharga in the south. It has been the scene of conflict in modern times, particularly during the Second World War. Administratively the Western Desert is d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ningxia Province
Ningxia, officially the Ningxia Hui Autonomous Region, is an Autonomous regions of China, autonomous region in Northwestern China. Formerly a Provinces of China, province, Ningxia was incorporated into Gansu in 1954 but was later separated from Gansu in 1958 and reconstituted as an autonomous region for the Hui people, one of the 56 officially recognised List of ethnic groups in China, nationalities of China. Twenty percent of China's Hui population lives in Ningxia. Ningxia is bounded by Shaanxi to the east, Gansu to the south and west and Inner Mongolia, Inner Mongolia Autonomous Region to the north and has an area of around . This sparsely settled, mostly desert region lies partially on the Loess Plateau and in the vast plain of the Yellow River and features the Great Wall of China along its northeastern boundary. Over about 2000 years, an extensive system of canals (with a total length of approximately 1397 kilometers) has been built from Qin dynasty. Extensive land reclamati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after India, representing 17.4% of the world population. China spans the equivalent of five time zones and Borders of China, borders fourteen countries by land across an area of nearly , making it the list of countries and dependencies by area, third-largest country by land area. The country is divided into 33 Province-level divisions of China, province-level divisions: 22 provinces of China, provinces, 5 autonomous regions of China, autonomous regions, 4 direct-administered municipalities of China, municipalities, and 2 semi-autonomous special administrative regions. Beijing is the country's capital, while Shanghai is List of cities in China by population, its most populous city by urban area and largest financial center. Considered one of six ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desert
A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the land surface of the Earth is arid or Semi-arid climate, semi-arid. This includes much of the Polar regions of Earth, polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location. Deserts are formed by weathering processes as large variations in temperature between day and night strain the Rock (geology), rocks, which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting frag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DK (publisher)
Dorling Kindersley Limited (branded as DK) is a British multinational publishing company specialising in illustrated reference books for adults and children in 63 languages. It is part of Penguin Random House, a subsidiary of German media conglomerate Bertelsmann. Established in 1974, DK publishes a range of titles in genres including travel (including DK Eyewitness Travel), history, geography, science, space, nature, sports, gardening, cookery, parenting and many others. The worldwide CEO of DK is Paul Kelly. DK has offices in New York, Melbourne, London, Munich, New Delhi, Toronto, Madrid, Beijing, and Jiangmen. DK works with licensing partners such as Disney, LEGO, DC Comics, the Royal Horticultural Society, MasterChef, and the Smithsonian Institution. DK has commissioned authors such as Mary Berry, Monty Don, Robert Winston, Huw Richards, and Steve Mould for a range of books. History DK was founded in 1974 by Christopher Dorling and Peter Kindersley in London as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barchan In Noachis
A barchan or barkhan dune (from Kazakh бархан ) is a crescent-shaped dune. Russian naturalist Alexander von Middendorf introduced the term in 1881, working from the occurrence of barchans in Turkestan and in other inland desert regions. Barchans "face" the wind, appearing convex, and are produced by wind action predominantly from one direction. They are a very common landform in sandy deserts all over the world and are arc-shaped, markedly asymmetrical in cross section, with a gentle slope facing toward the wind sand ridge, comprising well-sorted sand. This type of dune possesses two "horns" that face downwind, with the steeper slope known as the slip face, facing away from the wind, downwind, at the angle of repose of the sand in question, approximately 30–35 degrees for medium-fine dry sand. The upwind side is packed by the wind, and stands at about 15 degrees. Barchans may be high and wide at the base measured perpendicular to the wind. Simple barchan du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bagnold Formula
The Bagnold formula, named after Ralph Alger Bagnold, relates the amount of sand moved by the wind to wind speed by saltation. It states that the mass transport of sand is proportional to the third power of the friction velocity. Under steady conditions, this implies that mass transport is proportional to the third power of the excess of the wind speed (at any fixed height over the sand surface) over the minimum wind speed that is able to activate and sustain a continuous flow of sand grains. The formula was derived by Bagnold in 1936 and later published in his book '' The Physics of Blown Sand and Desert Dunes'' in 1941. Wind tunnel and field experiments suggest that the formula is basically correct. It has later been modified by several researchers, but is still considered to be the benchmark formula.Sørensen, M. 2004. On the rate of aeolian sand transport. Geomorphology 59:53-62. In its simplest form, Bagnold's formula may be expressed as: :q = C \ \frac\ \sqrt u_*^3 whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
