1.
Iowa
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Iowa is a U. S. state in the Midwestern United States, bordered by the Mississippi River on the east and the Missouri River and the Big Sioux River on the west. Surrounding states include Wisconsin and Illinois to the east, Missouri to the south, Nebraska and South Dakota to the west, in colonial times, Iowa was a part of French Louisiana and Spanish Louisiana, its state flag is patterned after the flag of France. After the Louisiana Purchase, people laid the foundation for an economy in the heart of the Corn Belt. Iowa is the 26th most extensive in area and the 30th most populous of the 50 United States. Its capital and largest city by population is Des Moines, Iowa has been listed as one of the safest states in which to live. Its nickname is the Hawkeye State, Iowa derives its name from the Ioway people, one of the many Native American tribes that occupied the state at the time of European exploration. Iowa is bordered by the Mississippi River on the east, the Missouri River and the Big Sioux River on the west, Iowa is the only state whose east and west borders are formed entirely by rivers. Iowa has 99 counties, but 100 county seats because Lee County has two, the state capital, Des Moines, is in Polk County. Iowas bedrock geology generally increases in age from west to east, in northwest Iowa, Cretaceous bedrock can be 74 million years old, in eastern Iowa Cambrian bedrock dates to c.500 million years ago. Iowa is generally not flat, most of the consists of rolling hills. Iowa can be divided into eight landforms based on glaciation, soils, topography, Loess hills lie along the western border of the state, some of which are several hundred feet thick. Northeast Iowa along the Mississippi River is part of the Driftless Zone, consisting of steep hills, several natural lakes exist, most notably Spirit Lake, West Okoboji Lake, and East Okoboji Lake in northwest Iowa. To the east lies Clear Lake, man-made lakes include Lake Odessa, Saylorville Lake, Lake Red Rock, Coralville Lake, Lake MacBride, and Rathbun Lake. The states northwest area has remnants of the once common wetlands. Iowas natural vegetation is tallgrass prairie and savanna in areas, with dense forest and wetlands in flood plains and protected river valleys. Most of Iowa is used for agriculture, crops cover 60% of the state, grasslands cover 30%, as of 2005 Iowa ranked 49th of U. S. states in public land holdings. Endangered or threatened plants include western prairie fringed orchid, eastern prairie fringed orchid, Meads milkweed, prairie bush clover, the explosion in the number of high-density livestock facilities in Iowa has led to increased rural water contamination and a decline in air quality. Iowa has a continental climate throughout the state
2.
Windmill
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A windmill is a mill that converts the energy of wind into rotational energy by means of vanes called sails or blades. Centuries ago, windmills usually were used to mill grain, pump water, thus they often were gristmills, windpumps, or both. The majority of modern windmills take the form of wind turbines used to generate electricity, the windwheel of the Greek engineer Heron of Alexandria in the first century is the earliest known instance of using a wind-driven wheel to power a machine. Another early example of a wheel was the prayer wheel. It has been claimed that the Babylonian emperor Hammurabi planned to use wind power for his ambitious project in the seventeenth century BCE. The first practical windmills had sails that rotated in a horizontal plane, according to Ahmad Y. al-Hassan, these panemone windmills were invented in eastern Persia as recorded by the Persian geographer Estakhri in the ninth century. The authenticity of an anecdote of a windmill involving the second caliph Umar is questioned on the grounds that it appears in a tenth-century document. Made of six to 12 sails covered in reed matting or cloth material, these windmills were used to grind grain or draw up water, Windmills were in widespread use across the Middle East and Central Asia, and later spread to China and India from there. A similar type of windmill with rectangular blades, used for irrigation, can also be found in thirteenth-century China. Horizontal windmills were built, in numbers, in Europe during the 18th and nineteenth centuries, for example Fowlers Mill at Battersea in London. Due to a lack of evidence, debate occurs among historians as to whether or not Middle Eastern horizontal windmills triggered the development of European windmills. In northwestern Europe, the horizontal-axis or vertical windmill is believed to date from the last quarter of the century in the triangle of northern France, eastern England. The earliest certain reference to a windmill in Europe dates from 1185, a number of earlier, but less certainly dated, twelfth-century European sources referring to windmills have also been found. These earliest mills were used to grind cereals, the evidence at present is that the earliest type of European windmill was the post mill, so named because of the large upright post on which the mills main structure is balanced. The body contains all the milling machinery, the first post mills were of the sunken type, where the post was buried in an earth mound to support it. Later, a wooden support was developed called the trestle and this was often covered over or surrounded by a roundhouse to protect the trestle from the weather and to provide storage space. This type of windmill was the most common in Europe until the nineteenth century, in a hollow-post mill, the post on which the body is mounted is hollowed out, to accommodate the drive shaft. This makes it possible to drive machinery below or outside the body still being able to rotate the body into the wind
3.
De Olifant, Burdaard
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De Olifant is a smock mill in Burdaard, Friesland, Netherlands which has been restored to working order. The mill is listed as a Rijksmonument, number 35673, De Olifant was originally built at Oostwold, Groningen in 1856 where it drained the Oosterwolderpolder. In 1867 it was moved to Burdaard where it drained the Olifantpolder, the cost of purchase and re-erection was ƒ2,000. The mill worked until 1970 when it was out of use. The mill was sold to Stichting De Fryske Mole on 20 June 1977, restoration was carried out in 1978-79 and again in 1991. De Olifant is what the Dutch describe as an achtkante grondzeiler and it is a smock mill winded by a winch. There is no stage, the sails reaching almost to the ground, the mill has a single-storey brick base and a two-storey smock. The smock has vertical weatherboarding and the cap is thatched, the four Common sails have a span of 23.90 metres and are carried in a cast-iron windshaft which was made by Prins van Oranje of Den Haag in 1877. The windshaft also carries the wheel, which has 65 cogs. This drives the wallower at the top of the upright shaft, at the bottom of the upright shaft, the great spur wheel drives three wooden shafts, each of which drives a wooden Archimedes screw via another set of gears. Two of the Archimedes screws drain the Olifant polder, while the third pumps water into the polder, the drive to the larger of the two Archimedes screws that drain the polder is from a 38-cog gear wheel meshing with the great spur wheel. This drives a 35-cog gear wheel which drives the Archimedes screw via a 46-cog gear wheel on the axle of the Archimedes screw and this Archimedes screw has an axle diameter of 440 millimetres and is 1.61 metres diameter overall. It is inclined at an angle of 17½°, each revolution of the screw lifts 1,528 litres of water. The drive to the smaller of the two Archimedes screws that drain the polder is from a 36 cog gear wheel meshing with the spur wheel. This drives a 33-cog gear wheel which drives the Archimedes screw via a 41-cog gear wheel on the axle of the Archimedes screw and this Archimedes screw has an axle diameter of 400 millimetres and is 1.31 metres diameter overall. It is inclined at an angle of 121°, each revolution of the screw lifts 649 litres of water. The drive to the Archimedes screw that pumps water into the polder is from a 38-cog gear wheel meshing with the spur wheel. This drives a 25 stave gear wheel which drives a wallower, the wallower drives a gear wheel with 31 cogs
4.
Burdaard
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Burdaard is a small village in Ferwerderadiel in the province of Friesland, the Netherlands. It had a population of around 1158 in 2014, there are two windmills in Burdaard. De Olifant is a mill dating from 1867 which has been restored to working order. De Zwaluw is a corn, pearl barley and sawmill which is working commercially, media related to Burdaard at Wikimedia Commons website about Burdaard
5.
Friesland
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Friesland or Frisia is a province in the northwest of the Netherlands. It is situated west of Groningen, northwest of Drenthe and Overijssel, north of Flevoland, northeast of North Holland, in 2010, the province had a population of 646,000 and a total area of 5,749 km2. The capital and seat of the government is the city of Leeuwarden. Since 2017, Arno Brok is the Kings Commissioner in the province, a coalition of the Labour Party, the Christian Democratic Appeal, and the Frisian National Party forms the executive branch. The province is divided into 24 municipalities, the area of the province was once part of the ancient, larger region of Frisia. The official languages of Friesland are West Lauwers Frisian and Dutch, a proto-Frisian culture slowly began to emerge around 400–200 BC known for its artificial dwelling hills as a defence against the sea. The Roman claim on Frisia began in 12 BC with the campaign of Nero Claudius Drusus in Germania, after a series of costly battles against the Frisians, the Romans were suddenly sworn fealty. The de facto independence they later enjoyed as a Roman vassal shows that this might have been a mostly diplomatic decision based on the temporary favourable bargaining position. Together with other Germanic tribes such as the Salians and the Batavii they managed to keep the north of the Lower Rhine mostly free from Roman influence. The early eighth-century AD is known for the Frisian Kingdom, king Redbad, after incorporation into the Frankish empire, Friesland was divided into three parts. The westernmost part developed at the start of the second millennium into the County of Holland, while the remainder of Frisia had no feudal overlord and that ended when Charles V added Frisia to the Habsburg Netherlands as Lordship of Frisia. Under Napoleon, the department was named Frise, after Napoleon was defeated in 1813, the department became part of the United Kingdom of the Netherlands as the province of Friesland. Friesland is the largest province of the Netherlands if one includes areas of water, in terms of land area only, the provinces highest point is at 45 metres above sea level, on the island of Vlieland. There are four parks, Schiermonnikoog, De Alde Feanen, Lauwersmeer. The ten urban areas in Friesland with the largest population are, The province is divided into 24 municipalities, the province of Friesland has an oceanic climate. In 2010, Friesland had a population of 646,305, the years 1880–1900 show slower population growth due to a farm crisis in which 20,000 Frisians emigrated to the United States of America. Since the late Middle Ages, Friesland has been renowned for the height of its inhabitants. Friesland is mainly an agricultural province, the black and white Frisian cattle, black and white Stabyhoun and the black Frisian horse originated here
6.
Afghanistan
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Afghanistan, officially the Islamic Republic of Afghanistan, is a landlocked country located within South Asia and Central Asia. It has a population of approximately 32 million, making it the 42nd most populous country in the world. It is bordered by Pakistan in the south and east, Iran in the west, Turkmenistan, Uzbekistan, and Tajikistan in the north and its territory covers 652,000 km2, making it the 41st largest country in the world. The land also served as the source from which the Kushans, Hephthalites, Samanids, Saffarids, Ghaznavids, Ghorids, Khiljis, Mughals, Hotaks, Durranis, the political history of the modern state of Afghanistan began with the Hotak and Durrani dynasties in the 18th century. In the late 19th century, Afghanistan became a state in the Great Game between British India and the Russian Empire. Following the Third Anglo-Afghan War in 1919, King Amanullah unsuccessfully attempted to modernize the country and it remained peaceful during Zahir Shahs forty years of monarchy. A series of coups in the 1970s was followed by a series of wars that devastated much of Afghanistan. The name Afghānistān is believed to be as old as the ethnonym Afghan, the root name Afghan was used historically in reference to a member of the ethnic Pashtuns, and the suffix -stan means place of in Persian. Therefore, Afghanistan translates to land of the Afghans or, more specifically in a historical sense, however, the modern Constitution of Afghanistan states that he word Afghan shall apply to every citizen of Afghanistan. An important site of historical activities, many believe that Afghanistan compares to Egypt in terms of the historical value of its archaeological sites. The country sits at a unique nexus point where numerous civilizations have interacted and it has been home to various peoples through the ages, among them the ancient Iranian peoples who established the dominant role of Indo-Iranian languages in the region. At multiple points, the land has been incorporated within large regional empires, among them the Achaemenid Empire, the Macedonian Empire, the Indian Maurya Empire, and the Islamic Empire. Archaeological exploration done in the 20th century suggests that the area of Afghanistan has been closely connected by culture and trade with its neighbors to the east, west. Artifacts typical of the Paleolithic, Mesolithic, Neolithic, Bronze, urban civilization is believed to have begun as early as 3000 BCE, and the early city of Mundigak may have been a colony of the nearby Indus Valley Civilization. More recent findings established that the Indus Valley Civilisation stretched up towards modern-day Afghanistan, making the ancient civilisation today part of Pakistan, Afghanistan, in more detail, it extended from what today is northwest Pakistan to northwest India and northeast Afghanistan. An Indus Valley site has found on the Oxus River at Shortugai in northern Afghanistan. There are several smaller IVC colonies to be found in Afghanistan as well, after 2000 BCE, successive waves of semi-nomadic people from Central Asia began moving south into Afghanistan, among them were many Indo-European-speaking Indo-Iranians. These tribes later migrated further into South Asia, Western Asia, the region at the time was referred to as Ariana
7.
Iran
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Iran, also known as Persia, officially the Islamic Republic of Iran, is a sovereign state in Western Asia. Comprising a land area of 1,648,195 km2, it is the second-largest country in the Middle East, with 82.8 million inhabitants, Iran is the worlds 17th-most-populous country. It is the country with both a Caspian Sea and an Indian Ocean coastline. The countrys central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, Tehran is the countrys capital and largest city, as well as its leading economic and cultural center. Iran is the site of to one of the worlds oldest civilizations, the area was first unified by the Iranian Medes in 625 BC, who became the dominant cultural and political power in the region. The empire collapsed in 330 BC following the conquests of Alexander the Great, under the Sassanid Dynasty, Iran again became one of the leading powers in the world for the next four centuries. Beginning in 633 AD, Arabs conquered Iran and largely displaced the indigenous faiths of Manichaeism and Zoroastrianism by Islam, Iran became a major contributor to the Islamic Golden Age that followed, producing many influential scientists, scholars, artists, and thinkers. During the 18th century, Iran reached its greatest territorial extent since the Sassanid Empire, through the late 18th and 19th centuries, a series of conflicts with Russia led to significant territorial losses and the erosion of sovereignty. Popular unrest culminated in the Persian Constitutional Revolution of 1906, which established a monarchy and the countrys first legislative body. Following a coup instigated by the U. K. Growing dissent against foreign influence and political repression led to the 1979 Revolution, Irans rich cultural legacy is reflected in part by its 21 UNESCO World Heritage Sites, the third-largest number in Asia and 11th-largest in the world. Iran is a member of the UN, ECO, NAM, OIC. Its political system is based on the 1979 Constitution which combines elements of a democracy with a theocracy governed by Islamic jurists under the concept of a Supreme Leadership. A multicultural country comprising numerous ethnic and linguistic groups, most inhabitants are Shia Muslims, the largest ethnic groups in Iran are the Persians, Azeris, Kurds and Lurs. Historically, Iran has been referred to as Persia by the West, due mainly to the writings of Greek historians who called Iran Persis, meaning land of the Persians. As the most extensive interactions the Ancient Greeks had with any outsider was with the Persians, however, Persis was originally referred to a region settled by Persians in the west shore of Lake Urmia, in the 9th century BC. The settlement was then shifted to the end of the Zagros Mountains. In 1935, Reza Shah requested the international community to refer to the country by its native name, opposition to the name change led to the reversal of the decision, and Professor Ehsan Yarshater, editor of Encyclopædia Iranica, propagated a move to use Persia and Iran interchangeably
8.
Pakistan
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Pakistan, officially the Islamic Republic of Pakistan, is a federal parliamentary republic in South Asia on the crossroads of Central Asia and Western Asia. It is the sixth-most populous country with a population exceeding 200 million people, in terms of area, it is the 33rd-largest country in the world with an area covering 881,913 square kilometres. It is separated from Tajikistan by Afghanistans narrow Wakhan Corridor in the north, Pakistan is unique among Muslim countries in that it is the only country to have been created in the name of Islam. As a result of the Pakistan Movement led by Muhammad Ali Jinnah and it is an ethnically and linguistically diverse country, with a similarly diverse geography and wildlife. Initially a dominion, Pakistan adopted a constitution in 1956, becoming an Islamic republic, an ethnic civil war in 1971 resulted in the secession of East Pakistan as the new country of Bangladesh. The new constitution stipulated that all laws were to conform to the injunctions of Islam as laid down in the Quran. Pakistan has an economy with a well-integrated agriculture sector. The Pakistani economy is the 24th-largest in the world in terms of purchasing power and it is ranked among the emerging and growth-leading economies of the world, and is backed by one of the worlds largest and fastest-growing middle classes. The post-independence history of Pakistan has been characterised by periods of military rule, the country continues to face challenging problems such as illiteracy, healthcare, and corruption, but has substantially reduced poverty and terrorism and expanded per capita income. It is also a member of CERN. Pakistan is a signatory to the Kyoto Protocol, the Paris Agreement, the name Pakistan literally means land of the pure in Urdu and Persian. It is a play on the word pāk meaning pure in Persian and Pashto, the letter i was incorporated to ease pronunciation and form the linguistically correct and meaningful name. Some of the earliest ancient human civilisations in South Asia originated from areas encompassing present-day Pakistan, the earliest known inhabitants in the region were Soanian during the Lower Paleolithic, of whom stone tools have been found in the Soan Valley of Punjab. The Vedic Civilization, characterised by Indo-Aryan culture, laid the foundations of Hinduism, Multan was an important Hindu pilgrimage centre. The Vedic civilisation flourished in the ancient Gandhāran city of Takṣaśilā, the Indo-Greek Kingdom founded by Demetrius of Bactria included Gandhara and Punjab and reached its greatest extent under Menander, prospering the Greco-Buddhist culture in the region. Taxila had one of the earliest universities and centres of education in the world. At its zenith, the Rai Dynasty of Sindh ruled this region, the Pala Dynasty was the last Buddhist empire, which, under Dharampala and Devapala, stretched across South Asia from what is now Bangladesh through Northern India to Pakistan. The Arab conqueror Muhammad bin Qasim conquered the Indus valley from Sindh to Multan in southern Punjab in 711 AD, the Pakistan governments official chronology identifies this as the time when the foundation of Pakistan was laid
9.
Muslim world
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The terms Muslim world and Islamic world commonly refer to the Islamic community, comprising all those who adhere to the religion of Islam, or to societies where Islam is practiced. In a modern sense, these terms refer to countries where Islam is widespread. In the modern era, most of the Muslim world came under influence or colonial domination of European powers. The nation states emerged in the post-colonial era have adopted a variety of political and economic models. As of 2015, over 1.7 billion or about 23. 4% of the population are Muslims including the 4. 4% who live as minorities. Muslim history involves the history of the Islamic faith as a religion, the history of Islam began in Arabia with the Islamic prophet Muhammads first recitations of the Quran in the 7th century in the month of Ramadan. However, Islam under the Rashidun Caliphate grew rapidly, a century after the death of last Islamic prophet Muhammad, the Islamic empire extended from Spain in the west to Indus in the east. The Islamic Golden Age coincided with the Middle Ages in the Muslim world, starting with the rise of Islam and establishment of the first Islamic state in 622. The end of the age is given as 1258 with the Mongolian Sack of Baghdad, or 1492 with the completion of the Christian Reconquista of the Emirate of Granada in Al-Andalus. The Abbasids were influenced by the Quranic injunctions and hadiths, such as the ink of a scholar is more holy than the blood of a martyr, that stressed the value of knowledge. The major Islamic capital cities of Baghdad, Cairo, and Córdoba became the intellectual centers for science, philosophy, medicine. Between the 8th and 18th centuries, the use of glaze was prevalent in Islamic art. Tin-opacified glazing was one of the earliest new technologies developed by the Islamic potters, the first Islamic opaque glazes can be found as blue-painted ware in Basra, dating to around the 8th century. Another contribution was the development of fritware, originating from 9th century Iraq, other centers for innovative ceramic pottery in the Old world included Fustat, Damascus and Tabriz. The original concept is derived from a pre-Islamic Persian prototype Hezār Afsān that relied on particular Indian elements and it reached its final form by the 14th century, the number and type of tales have varied from one manuscript to another. All Arabian fantasy tales tend to be called Arabian Nights stories when translated into English, regardless of whether they appear in The Book of One Thousand and this work has been very influential in the West since it was translated in the 18th century, first by Antoine Galland. Imitations were written, especially in France, various characters from this epic have themselves become cultural icons in Western culture, such as Aladdin, Sinbad the Sailor and Ali Baba. A famous example of Arabic poetry and Persian poetry on romance is Layla and Majnun and it is a tragic story of undying love much like the later Romeo and Juliet, which was itself said to have been inspired by a Latin version of Layla and Majnun to an extent
10.
China
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China, officially the Peoples Republic of China, is a unitary sovereign state in East Asia and the worlds most populous country, with a population of over 1.381 billion. The state is governed by the Communist Party of China and its capital is Beijing, the countrys major urban areas include Shanghai, Guangzhou, Beijing, Chongqing, Shenzhen, Tianjin and Hong Kong. China is a power and a major regional power within Asia. Chinas landscape is vast and diverse, ranging from forest steppes, the Himalaya, Karakoram, Pamir and Tian Shan mountain ranges separate China from much of South and Central Asia. The Yangtze and Yellow Rivers, the third and sixth longest in the world, respectively, Chinas coastline along the Pacific Ocean is 14,500 kilometers long and is bounded by the Bohai, Yellow, East China and South China seas. China emerged as one of the worlds earliest civilizations in the basin of the Yellow River in the North China Plain. For millennia, Chinas political system was based on hereditary monarchies known as dynasties, in 1912, the Republic of China replaced the last dynasty and ruled the Chinese mainland until 1949, when it was defeated by the communist Peoples Liberation Army in the Chinese Civil War. The Communist Party established the Peoples Republic of China in Beijing on 1 October 1949, both the ROC and PRC continue to claim to be the legitimate government of all China, though the latter has more recognition in the world and controls more territory. China had the largest economy in the world for much of the last two years, during which it has seen cycles of prosperity and decline. Since the introduction of reforms in 1978, China has become one of the worlds fastest-growing major economies. As of 2016, it is the worlds second-largest economy by nominal GDP, China is also the worlds largest exporter and second-largest importer of goods. China is a nuclear weapons state and has the worlds largest standing army. The PRC is a member of the United Nations, as it replaced the ROC as a permanent member of the U. N. Security Council in 1971. China is also a member of numerous formal and informal multilateral organizations, including the WTO, APEC, BRICS, the Shanghai Cooperation Organization, the BCIM, the English name China is first attested in Richard Edens 1555 translation of the 1516 journal of the Portuguese explorer Duarte Barbosa. The demonym, that is, the name for the people, Portuguese China is thought to derive from Persian Chīn, and perhaps ultimately from Sanskrit Cīna. Cīna was first used in early Hindu scripture, including the Mahābhārata, there are, however, other suggestions for the derivation of China. The official name of the state is the Peoples Republic of China. The shorter form is China Zhōngguó, from zhōng and guó and it was then applied to the area around Luoyi during the Eastern Zhou and then to Chinas Central Plain before being used as an occasional synonym for the state under the Qing
11.
Indian subcontinent
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Geologically, the Indian subcontinent is related to the land mass that rifted from Gondwana and merged with the Eurasian plate nearly 55 million years ago. Geographically, it is the region in south-central Asia delineated by the Himalayas in the north, the Hindu Kush in the west. Politically, the Indian subcontinent usually includes Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, sometimes, the term South Asia is used interchangeably with Indian subcontinent. There is no consensus about which countries should be included in each and it is first attested in 1845 to refer to the North and South Americas, before they were regarded as separate continents. Its use to refer to the Indian subcontinent is seen from the twentieth century. It was especially convenient for referring to the region comprising both the British India and the states under British Paramountcy. The term Indian subcontinent also has a geological significance and it was, like the various continents, a part of the supercontinent of Gondwana. A series of tectonic splits caused formation of basins, each drifting in various directions. The geological region called the Greater India once included the Madagascar, Seychelles, Antartica, as a geological term, Indian subcontinent has meant that region formed from the collision of the Indian basin with Eurasia nearly 55 million years ago, towards the end of Paleocene. The Indian subcontinent has been a particularly common in the British Empire. The region, state Mittal and Thursby, has also labelled as India, Greater India. The BBC and some sources refer to the region as the Asian Subcontinent. Some academics refer to it as South Asian Subcontinent, the terms Indian subcontinent and South Asia are sometimes used interchangeably. There is no accepted definition on which countries are a part of South Asia or Indian subcontinent. In dictionary entries, the term subcontinent signifies a large, distinguishable subdivision of a continent, the region experienced high volcanic activity and plate subdivisions, creating Madagascar, Seychelles, Antartica, Austrolasia and the Indian subcontinent basin. The Indian subcontinent drifted northeastwards, colliding with the Eurasian plate nearly 55 million years ago and this geological region largely includes Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. The zone where the Eurasian and Indian subcontinent plates meet remains one of the active areas. The English term mainly continues to refer to the Indian subcontinent, physiographically, it is a peninsular region in south-central Asia delineated by the Himalayas in the north, the Hindu Kush in the west, and the Arakanese in the east
12.
Netherlands
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The Netherlands, also informally known as Holland is the main constituent country of the Kingdom of the Netherlands. It is a densely populated country located in Western Europe with three territories in the Caribbean. The European part of the Netherlands borders Germany to the east, Belgium to the south, and the North Sea to the northwest, sharing borders with Belgium, the United Kingdom. The three largest cities in the Netherlands are Amsterdam, Rotterdam and The Hague, Amsterdam is the countrys capital, while The Hague holds the Dutch seat of parliament and government. The port of Rotterdam is the worlds largest port outside East-Asia, the name Holland is used informally to refer to the whole of the country of the Netherlands. Netherlands literally means lower countries, influenced by its low land and flat geography, most of the areas below sea level are artificial. Since the late 16th century, large areas have been reclaimed from the sea and lakes, with a population density of 412 people per km2 –507 if water is excluded – the Netherlands is classified as a very densely populated country. Only Bangladesh, South Korea, and Taiwan have both a population and higher population density. Nevertheless, the Netherlands is the worlds second-largest exporter of food and agricultural products and this is partly due to the fertility of the soil and the mild climate. In 2001, it became the worlds first country to legalise same-sex marriage, the Netherlands is a founding member of the EU, Eurozone, G-10, NATO, OECD and WTO, as well as being a part of the Schengen Area and the trilateral Benelux Union. The first four are situated in The Hague, as is the EUs criminal intelligence agency Europol and this has led to the city being dubbed the worlds legal capital. The country also ranks second highest in the worlds 2016 Press Freedom Index, the Netherlands has a market-based mixed economy, ranking 17th of 177 countries according to the Index of Economic Freedom. It had the thirteenth-highest per capita income in the world in 2013 according to the International Monetary Fund, in 2013, the United Nations World Happiness Report ranked the Netherlands as the seventh-happiest country in the world, reflecting its high quality of life. The Netherlands also ranks joint second highest in the Inequality-adjusted Human Development Index, the region called Low Countries and the country of the Netherlands have the same toponymy. Place names with Neder, Nieder, Nether and Nedre and Bas or Inferior are in use in all over Europe. They are sometimes used in a relation to a higher ground that consecutively is indicated as Upper, Boven, Oben. In the case of the Low Countries / the Netherlands the geographical location of the region has been more or less downstream. The geographical location of the region, however, changed over time tremendously
13.
East Anglia
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East Anglia is a geographical area in the East of England. The area included has varied but the legally defined NUTS2 statistical unit, comprises the counties of Norfolk, Suffolk and Cambridgeshire, the name derives from the Anglo-Saxon kingdom of the East Angles, a tribe that originated in Angeln, northern Germany. Definitions of what constitutes East Anglia vary, the Anglo-Saxon Kingdom of East Anglia, established in the 6th century, originally consisted of the modern counties of Norfolk and Suffolk and expanded west into at least part of Cambridgeshire. The modern NUTS2 statistical unit of East Anglia comprises Norfolk, Suffolk and those three counties have formed the Roman Catholic Diocese of East Anglia since 1976, and were the subject of a possible government devolution package in 2016. Essex has sometimes included in definitions of East Anglia, including by the London Society of East Anglians. However, the Kingdom of Essex to the south, was an element of the Heptarchy of Anglo-Saxon England and did not identify as Angles. The county of Essex by itself forms a NUTS2 statistical unit in the East of England region, other definitions of the area have been used or proposed over the years. For example, the Redcliffe-Maud Report in 1969, which followed the Royal Commission on the Reform of Local Government, the proposed East Anglia province would have included northern Essex, southern Lincolnshire and a small part of Northamptonshire as well as Cambridgeshire, Norfolk and Suffolk. The kingdom of East Anglia initially consisted of Norfolk and Suffolk, but upon the marriage of the East Anglian princess Etheldreda, the kingdom was formed about the year 520 by the merging of the North and the South Folk and was one of the seven Anglo-Saxon heptarchy kingdoms. However, this did not last and over the forty years East Anglia was defeated by the Mercians twice. Finally, in 794, Offa of Mercia had king Æthelberht killed, although independence was temporarily restored by rebellion in 825, on the 20 November 869 the Danes killed King Edmund and captured the kingdom. By 917, after a succession of Danish defeats, East Anglia was incorporated into the Kingdom of England by Edward the Elder, afterwards becoming an earldom. Despite some engineering work in the form of sea barriers constructed by the Roman Empire, much of East Anglia remained marshland and bogs until the 17th century. In the 1630s thousands of Puritan families from East Anglia settled in the American region of New England, East Anglia was ideally suited to airfield construction as it comprises large areas of open, level terrain and is close to mainland Europe. The reduced flight time to mainland Europe therefore reduced the load required and enabled a larger bomb load to be carried. Building the airfields was a civil engineering project and by the end of the war there was one approximately every 8 miles. Many of these airfields can still be today, particularly from aerial photographs, and a few remain is use today. Pillboxes, which were erected in 1940 to help defend the nation against invasion, can also be found throughout the area at strategic points
14.
Great Britain
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Great Britain, also known as Britain, is a large island in the north Atlantic Ocean off the northwest coast of continental Europe. With an area of 209,331 km2, Great Britain is the largest European island, in 2011 the island had a population of about 61 million people, making it the worlds third-most populous island after Java in Indonesia and Honshu in Japan. The island of Ireland is situated to the west of it, the island is dominated by a maritime climate with quite narrow temperature differences between seasons. Politically, the island is part of the United Kingdom of Great Britain and Northern Ireland, most of England, Scotland, and Wales are on the island. The term Great Britain often extends to surrounding islands that form part of England, Scotland, and Wales. A single Kingdom of Great Britain resulted from the union of the Kingdom of England, the archipelago has been referred to by a single name for over 2000 years, the term British Isles derives from terms used by classical geographers to describe this island group. By 50 BC Greek geographers were using equivalents of Prettanikē as a name for the British Isles. However, with the Roman conquest of Britain the Latin term Britannia was used for the island of Great Britain, the oldest mention of terms related to Great Britain was by Aristotle, or possibly by Pseudo-Aristotle, in his text On the Universe, Vol. III. To quote his works, There are two large islands in it, called the British Isles, Albion and Ierne. The name Britain descends from the Latin name for Britain, Britannia or Brittānia, Old French Bretaigne and Middle English Bretayne, Breteyne. The French form replaced the Old English Breoton, Breoten, Bryten, Breten, Britannia was used by the Romans from the 1st century BC for the British Isles taken together. It is derived from the writings of the Pytheas around 320 BC. Marcian of Heraclea, in his Periplus maris exteri, described the group as αἱ Πρεττανικαὶ νῆσοι. The peoples of these islands of Prettanike were called the Πρεττανοί, Priteni is the source of the Welsh language term Prydain, Britain, which has the same source as the Goidelic term Cruithne used to refer to the early Brythonic-speaking inhabitants of Ireland. The latter were later called Picts or Caledonians by the Romans, the Greco-Egyptian scientist Ptolemy referred to the larger island as great Britain and to Ireland as little Britain in his work Almagest. The name Albion appears to have out of use sometime after the Roman conquest of Britain. After the Anglo-Saxon period, Britain was used as a term only. It was used again in 1604, when King James VI and I styled himself King of Great Brittaine, France, Great Britain refers geographically to the island of Great Britain, politically to England, Scotland and Wales in combination
15.
Middle Ages
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In the history of Europe, the Middle Ages or Medieval Period lasted from the 5th to the 15th century. It began with the fall of the Western Roman Empire and merged into the Renaissance, the Middle Ages is the middle period of the three traditional divisions of Western history, classical antiquity, the medieval period, and the modern period. The medieval period is subdivided into the Early, High. Population decline, counterurbanisation, invasion, and movement of peoples, the large-scale movements of the Migration Period, including various Germanic peoples, formed new kingdoms in what remained of the Western Roman Empire. In the seventh century, North Africa and the Middle East—once part of the Byzantine Empire—came under the rule of the Umayyad Caliphate, although there were substantial changes in society and political structures, the break with classical antiquity was not complete. The still-sizeable Byzantine Empire survived in the east and remained a major power, the empires law code, the Corpus Juris Civilis or Code of Justinian, was rediscovered in Northern Italy in 1070 and became widely admired later in the Middle Ages. In the West, most kingdoms incorporated the few extant Roman institutions, monasteries were founded as campaigns to Christianise pagan Europe continued. The Franks, under the Carolingian dynasty, briefly established the Carolingian Empire during the later 8th, the Crusades, first preached in 1095, were military attempts by Western European Christians to regain control of the Holy Land from Muslims. Kings became the heads of centralised nation states, reducing crime and violence, intellectual life was marked by scholasticism, a philosophy that emphasised joining faith to reason, and by the founding of universities. Controversy, heresy, and the Western Schism within the Catholic Church paralleled the conflict, civil strife. Cultural and technological developments transformed European society, concluding the Late Middle Ages, the Middle Ages is one of the three major periods in the most enduring scheme for analysing European history, classical civilisation, or Antiquity, the Middle Ages, and the Modern Period. Medieval writers divided history into periods such as the Six Ages or the Four Empires, when referring to their own times, they spoke of them as being modern. In the 1330s, the humanist and poet Petrarch referred to pre-Christian times as antiqua, leonardo Bruni was the first historian to use tripartite periodisation in his History of the Florentine People. Bruni and later argued that Italy had recovered since Petrarchs time. The Middle Ages first appears in Latin in 1469 as media tempestas or middle season, in early usage, there were many variants, including medium aevum, or middle age, first recorded in 1604, and media saecula, or middle ages, first recorded in 1625. The alternative term medieval derives from medium aevum, tripartite periodisation became standard after the German 17th-century historian Christoph Cellarius divided history into three periods, Ancient, Medieval, and Modern. The most commonly given starting point for the Middle Ages is 476, for Europe as a whole,1500 is often considered to be the end of the Middle Ages, but there is no universally agreed upon end date. English historians often use the Battle of Bosworth Field in 1485 to mark the end of the period
16.
Simon Stevin
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Simon Stevin, sometimes called Stevinus, was a Flemish/Dutch/Netherlandish mathematician, physicist and engineer. He was active in a great areas of science and engineering. Very little is known with certainty about Stevins life and what we know is mostly inferred from other recorded facts, the exact birth date and the date and place of his death are uncertain. It is assumed he was born in Bruges since he enrolled at Leiden University under the name Simon Stevinus Brugensis and his name is usually written as Stevin, but some documents regarding his father use the spelling Stevijn. This is a normal spelling shift in 16th century Dutch and he was born around the year 1548 to unmarried parents, Anthonis Stevin and Catelyne van der Poort. His father is believed to have been a son of a mayor of Veurne. While Simons father was not mentioned in the book of burghers, many other Stevins were later mentioned in the Poorterboeken. Simon Stevins mother Cathelijne was the daughter of a family from Ypres. Her father Hubert was a poorter of Bruges, Simons mother Cathelijne later married Joost Sayon who was involved in the carpet and silk trade and a member of the schuttersgilde Sint-Sebastiaan. Through her marriage Cathelijne became a member of a family of Calvinists and it is believed that Stevin grew up in a relatively affluent environment and enjoyed a good education. He was likely educated at a Latin school in his hometown, Stevin left Bruges in 1571 apparently without a particular destination. Stevin was most likely a Calvinist since a Catholic would likely not have risen to the position of trust he later occupied with Maurice, Prince of Orange and it is assumed that he left Bruges to escape the religious persecution of Protestants by the Spanish rulers. Based on references in his work Wisconstighe Ghedaechtenissen, it has been inferred that he must have moved first to Antwerp where he began his career as a merchants clerk. Some biographers mention that he travelled to Prussia, Poland, Denmark, Norway and Sweden and other parts of Northern Europe and it is possible that he completed these travels over a longer period of time. In 1577 Simon Stevin returned to Bruges and was appointed city clerk by the aldermen of Bruges and he worked in the office of Jan de Brune of the Brugse Vrije, the castellany of Bruges. Why he had returned to Bruges in 1577 is not clear and it may have been related to the political events of that period. Bruges was the scene of religious conflict. Catholics and Calvinists alternately controlled the government of the city and they usually opposed each other but would occasionally collaborate in order to counteract the dictates of King Philip II of Spain
17.
Sluice
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A sluice is a water channel controlled at its head by a gate. A mill race, leet, flume, penstock or lade is a sluice channelling water toward a water mill, the terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry. A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway, Sluice gates commonly control water levels and flow rates in rivers and canals. They are also used in treatment plants and to recover minerals in mining operations. Sluice gate refers to a gate allowing water to flow under it. When a sluice is lowered, water may spill over the top, usually, a mechanism drives the sluice up or down. This may be a simple, hand-operated, chain pulled/lowered, worm drive or rack-and-pinion drive, flap sluice gate A fully automatic type, controlled by the pressure head across it, operation is similar to that of a check valve. It is a gate hinged at the top, when pressure is from one side, the gate is kept closed, a pressure from the other side opens the sluice when a threshold pressure is surpassed. Vertical rising sluice gate A plate sliding in the vertical direction, radial sluice gate A structure, where a small part of a cylindrical surface serves as the gate, supported by radial constructions going through the cylinders radius. On occasion, a counterweight is provided, rising sector sluice gate Also a part of a cylindrical surface, which rests at the bottom of the channel and rises by rotating around its centre. Needle sluice A sluice formed by a number of thin needles held against a solid frame through water pressure as in a needle dam. The gates of a Guillotine lock work in a way similar to a sluice gate, in the mountains of the United States, sluices transported logs from steep hillsides to downslope sawmill ponds or yarding areas. Nineteenth-century logging was traditionally a winter activity for men who spent summers working on farms, where there were freezing nights, water might be applied to logging sluices every night so a fresh coating of slippery ice would reduce friction of logs placed in the sluice the following morning. Sluice boxes are used in the recovery of black sands, gold. They may be small-scale, as used in prospecting, or much larger, as in commercial operations, typical sluices have transverse riffles over a carpet, which trap the heavy minerals, gemstones, and other valuable minerals. Cast Iron Cast iron has been popular when constructing sluice gates for years and this material is great at keeping the strength needed when dealing with powerful water levels. Stainless Steel Stainless steel in most cases is lighter than the older cast iron material, fibre-reinforced plastic Rather recently a new technologies such as fibre-reinforced plastic are being used to build sluices. This modern technology has many of the attributes as the older ways while bringing in new attributes such as corrosion resistance, in the Somerset Levels, sluice gates are known as clyse or clyce
18.
Spillway
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A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically the riverbed of the dammed river itself. In the UK they may be known as overflow channels, spillways ensure that the water does not overflow and damage or destroy the dam. Floodgates and fuse plugs may be designed into spillways to regulate water flow, other uses of the term spillway include bypasses of dams or outlets of channels used during high water, and outlet channels carved through natural dams such as moraines. Water normally flows over a spillway only during flood periods – when the reservoir cannot hold the excess of water entering the reservoir over the amount used. In contrast, a tower is a structure used to release water on a regular basis for water supply, hydroelectricity generation. A spillway is located at the top of the reservoir pool, dams may also have bottom outlets with valves or gates which may be operated to release flood flow, and a few dams lack overflow spillways and rely entirely on bottom outlets. There are two types of spillways, controlled and uncontrolled. A controlled spillway has mechanical structures or gates to regulate the rate of flow and this design allows nearly the full height of the dam to be used for water storage year-round, and flood waters can be released as required by opening one or more gates. An uncontrolled spillway, in contrast, does not have gates, the rate of discharge is controlled only by the depth of water above the reservoirs spillway. Storage volume in the reservoir above the spillway crest can only be used for the storage of floodwater. In an intermediate type, normal level regulation of the reservoir is controlled by the mechanical gates, if inflow to the reservoir exceeds the gates capacity, an artificial channel called either an auxiliary or emergency spillway that is blocked by a fuse plug dike will operate. The fuse plug is designed to over-top and wash out in case of a large flood, the fuse plug concept is used where it would be very costly to build a spillway with capacity for the probable maximum flood. A chute spillway is a common and basic design which transfers water from behind the dam down a smooth decline into the river below. These are usually designed following an ogee curve, most often, they are lined on the bottom and sides with concrete to protect the dam and topography. They may have a device and some are thinner and multiply lined if space. In addition, they are not always intended to dissipate energy like stepped spillways, chute spillways can be ingrained with a baffle of concrete blocks but usually have a flip lip and/or dissipator basin which creates a hydraulic jump, protecting the toe of the dam from erosion. Stepped channels and spillways have been used for over 3,000 years, the steps produce considerable energy dissipation along the chute and reduce the size of the required downstream energy dissipation basin. Research is still active on the topic, with developments on embankment dam overflow protection systems, converging spillways
19.
Flood
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A flood is an overflow of water that submerges land which is usually dry. The European Union Floods Directive defines a flood as a covering by water of land not normally covered by water, in the sense of flowing water, the word may also be applied to the inflow of the tide. Floods can also occur in rivers when the flow exceeds the capacity of the river channel. Floods often cause damage to homes and businesses if they are in the flood plains of rivers. Some floods develop slowly, while others such as floods, can develop in just a few minutes. Additionally, floods can be local, impacting a neighborhood or community, or very large, the word flood comes from the Old English flod, a word common to Germanic languages. Deluge myths are stories of a great flood sent by a deity or deities to destroy civilization as an act of divine retribution. Floods can happen on flat or low-lying areas when water is supplied by rainfall or snowmelt more rapidly than it can infiltrate or run off. The excess accumulates in place, sometimes to hazardous depths, surface soil can become saturated, which effectively stops infiltration, where the water table is shallow, such as a floodplain, or from intense rain from one or a series of storms. Infiltration also is slow to negligible through frozen ground, rock, concrete, paving, areal flooding begins in flat areas like floodplains and in local depressions not connected to a stream channel, because the velocity of overland flow depends on the surface slope. Endorheic basins may experience flooding during periods when precipitation exceeds evaporation. Floods occur in all types of river and stream channels, from the smallest ephemeral streams in humid zones to normally-dry channels in arid climates to the worlds largest rivers. When overland flow occurs on tilled fields, it can result in a flood where sediments are picked up by run off. Localized flooding may be caused or exacerbated by drainage obstructions such as landslides, ice, debris, slow-rising floods most commonly occur in large rivers with large catchment areas. The increase in flow may be the result of sustained rainfall, rapid snow melt, monsoons, the cause may be localized convective precipitation or sudden release from an upstream impoundment created behind a dam, landslide, or glacier. In one instance, a flood killed eight people enjoying the water on a Sunday afternoon at a popular waterfall in a narrow canyon. Without any observed rainfall, the rate increased from about 50 to 1,500 cubic feet per second in just one minute. Two larger floods occurred at the site within a week
20.
Gear
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A gear or cogwheel is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part to transmit torque. Geared devices can change the speed, torque, and direction of a power source, Gears almost always produce a change in torque, creating a mechanical advantage, through their gear ratio, and thus may be considered a simple machine. The teeth on the two meshing gears all have the same shape, two or more meshing gears, working in a sequence, are called a gear train or a transmission. A gear can mesh with a linear toothed part, called a rack, the gears in a transmission are analogous to the wheels in a crossed, belt pulley system. An advantage of gears is that the teeth of a gear prevent slippage, in transmissions with multiple gear ratios—such as bicycles, motorcycles, and cars—the term gear as in first gear refers to a gear ratio rather than an actual physical gear. The term describes similar devices, even when the ratio is continuous rather than discrete, or when the device does not actually contain gears. Early examples of gears date from the 4th century BC in China, examples of further development include, Ma Jun used gears as part of a south-pointing chariot. The Antikythera mechanism is an example of an early and intricate geared device. Its time of construction is now estimated between 150 and 100 BC, the water-powered grain-mill, the water-powered saw mill, fulling mill, and other applications of watermill often used gears. The first mechanical clocks were built in AD725, the 1386 Salisbury cathedral clock may be the worlds oldest working mechanical clock. The definite ratio that teeth give gears provides an advantage over other drives in precision machines such as watches that depend upon an exact velocity ratio, an external gear is one with the teeth formed on the outer surface of a cylinder or cone. Conversely, a gear is one with the teeth formed on the inner surface of a cylinder or cone. For bevel gears, a gear is one with the pitch angle exceeding 90 degrees. Internal gears do not cause output shaft direction reversal, spur gears or straight-cut gears are the simplest type of gear. They consist of a cylinder or disk with teeth projecting radially, though the teeth are not straight-sided, the edge of each tooth is straight and aligned parallel to the axis of rotation. These gears mesh together correctly only if fitted to parallel shafts, No axial thrust is created by the tooth loads. Spur gears are excellent at moderate speeds but tend to be noisy at high speeds, helical or dry fixed gears offer a refinement over spur gears. The leading edges of the teeth are not parallel to the axis of rotation, since the gear is curved, this angling makes the tooth shape a segment of a helix
21.
Patent
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A patent is a set of exclusive rights granted by a sovereign state to an inventor or assignee for a limited period of time in exchange for detailed public disclosure of an invention. An invention is a solution to a technological problem and is a product or a process. Patents are a form of intellectual property, the procedure for granting patents, requirements placed on the patentee, and the extent of the exclusive rights vary widely between countries according to national laws and international agreements. Typically, however, a patent application must include one or more claims that define the invention. A patent may include many claims, each of which defines a specific property right and these claims must meet relevant patentability requirements, such as novelty, usefulness, and non-obviousness. Nevertheless, there are variations on what is patentable subject matter from country to country, the word patent originates from the Latin patere, which means to lay open. More directly, it is a version of the term letters patent. Similar grants included land patents, which were land grants by early state governments in the USA, and printing patents, a precursor of modern copyright. In modern usage, the term patent usually refers to the granted to anyone who invents any new, useful. The additional qualification utility patent is used to distinguish the primary meaning from these other types of patents. Particular species of patents for inventions include biological patents, business method patents, chemical patents, the period of protection was 10 years. These were mostly in the field of glass making, as Venetians emigrated, they sought similar patent protection in their new homes. This led to the diffusion of patent systems to other countries, by the 16th century, the English Crown would habitually abuse the granting of letters patent for monopolies. After public outcry, King James I of England was forced to revoke all existing monopolies, the Statute became the foundation for later developments in patent law in England and elsewhere. Important developments in patent law emerged during the 18th century through a process of judicial interpretation of the law. During the reign of Queen Anne, patent applications were required to supply a complete specification of the principles of operation of the invention for public access. Influenced by the philosophy of John Locke, the granting of patents began to be viewed as a form of property right. The English legal system became the foundation for patent law in countries with a common law heritage, including the United States, New Zealand, in the Thirteen Colonies, inventors could obtain patents through petition to a given colonys legislature
22.
Region of Murcia
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The Region of Murcia is an autonomous community of Spain located in the southeast of the state, between Andalusia and Valencian Community, on the Mediterranean coast. The autonomous community consists of a province, unlike most autonomous communities. Because of this, the community and the province are operated as one unit of government. The city of Murcia is the capital of the region and seat of government organs, except for the parliament, the Regional Assembly of Murcia, the autonomous community and province is subdivided into municipalities. The Region of Murcia is bordered by Andalusia, Castile–La Mancha, the Valencian Community, the community measures 11,313 km² and has a population of 1.4 million, of whom one-third live in the capital. The highest mountain is Los Obispos, the region is a major producer of fruits, vegetables, and flowers for the rest of Spain and Europe. Wineries have developed near the towns of Bullas, Yecla, and Jumilla, Murcia is mainly a warm region which has made it very suitable for agriculture. The region is located in the part of the Cordilleras Béticas mountains. These mountain ranges are divided as well in the Prebética, Subbética and Penibética mountain ranges, approximately 27% of the Murcian territory can be described as mountainous, 38% as intramountainous depressions and running valleys, and the remaining 35% as flat lands and plateaux. The Region of Murcia enjoys a Mediterranean climate of semi-arid type, with mild winters, the average annual temperature is 18 °C. With little precipitation of about 300 to 350 mm per year, april and October are the months with the most precipitation, there being frequent heavy downpours in a single day. The city of Murcia holds the temperature of the 20th century in Spain. It reached 46.1 °C on July 4,1994, the winter of 2005 was the coldest in a long time, with snow even falling on the Murcian coast. The hydrographic network of the region is made up of the Segura river and its affluents, Mundo, alhárabe and its affluent, the Benamor. Due to the water supplying incapacity of the Segura river basin, contributions to this basin are made, originated from the basin of the Tajo river. The greatest natural lake of Spain can be found in the region and it is a salt water lagoon, adjacent to the Mediterranean Sea. Its special ecological and natural characteristics make the Mar Menor a unique natural place, with a semicircular shape, it is separated from the Mediterranean Sea by a sand strip 22 km in length and between 100 and 1200 m wide, known as La Manga del Mar Menor. The lagoon has been designated by the United Nations as a Specially Protected Zone of Importance for the Mediterranean and its coastal perimeter accounts for 73 km of coast in which beaches follow one another with crystal clear shallow water
23.
Spain
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By population, Spain is the sixth largest in Europe and the fifth in the European Union. Spains capital and largest city is Madrid, other urban areas include Barcelona, Valencia, Seville, Bilbao. Modern humans first arrived in the Iberian Peninsula around 35,000 years ago, in the Middle Ages, the area was conquered by Germanic tribes and later by the Moors. Spain is a democracy organised in the form of a government under a constitutional monarchy. It is a power and a major developed country with the worlds fourteenth largest economy by nominal GDP. Jesús Luis Cunchillos argues that the root of the span is the Phoenician word spy. Therefore, i-spn-ya would mean the land where metals are forged, two 15th-century Spanish Jewish scholars, Don Isaac Abravanel and Solomon ibn Verga, gave an explanation now considered folkloric. Both men wrote in two different published works that the first Jews to reach Spain were brought by ship by Phiros who was confederate with the king of Babylon when he laid siege to Jerusalem. This man was a Grecian by birth, but who had given a kingdom in Spain. He became related by marriage to Espan, the nephew of king Heracles, Heracles later renounced his throne in preference for his native Greece, leaving his kingdom to his nephew, Espan, from whom the country of España took its name. Based upon their testimonies, this eponym would have already been in use in Spain by c.350 BCE, Iberia enters written records as a land populated largely by the Iberians, Basques and Celts. Early on its coastal areas were settled by Phoenicians who founded Western Europe´s most ancient cities Cadiz, Phoenician influence expanded as much of the Peninsula was eventually incorporated into the Carthaginian Empire, becoming a major theater of the Punic Wars against the expanding Roman Empire. After an arduous conquest, the peninsula came fully under Roman Rule, during the early Middle Ages it came under Germanic rule but later, much of it was conquered by Moorish invaders from North Africa. In a process took centuries, the small Christian kingdoms in the north gradually regained control of the peninsula. The last Moorish kingdom fell in the same year Columbus reached the Americas, a global empire began which saw Spain become the strongest kingdom in Europe, the leading world power for a century and a half, and the largest overseas empire for three centuries. Continued wars and other problems led to a diminished status. The Napoleonic invasions of Spain led to chaos, triggering independence movements that tore apart most of the empire, eventually democracy was peacefully restored in the form of a parliamentary constitutional monarchy. Spain joined the European Union, experiencing a renaissance and steady economic growth
24.
Noria
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A noria is a machine activated by water power and used for lifting water into a small aqueduct, either for the purpose of irrigation or for the use in towns and villages. There is at least one instance where it feeds seawater into a saltern. The terms referring to traditional water-raising devices used in the Middle East, India, Spain, the term noria is commonly used for devices using the power of moving water. For devices powered by animals, the term is sakia or saqiya. Other types of devices are grouped under the name of chain pumps. In Spain the term noria is used also for devices which are actually sakias, the proper noria uses the energy derived from the flow of a river. It consists of a large, very narrow undershot water wheel whose rim is made up of a series of containers which lift water from the river to a small aqueduct at the top of the wheel. A sakia or saqiya differs from a noria in the way it is powered, the most primitive sakias are driven by donkeys, mules, or oxen. The animal turns a wheel, which is engaged with the vertical one. In Spanish an animal-driven sakia is named aceña, with the exception of the Cartagena area, another, much rarer type of sakia uses the same system, of a necklace of clay or wooden buckets, but it is driven by the wind. The wind-driven sakias in the vicinity of Cartagena, are identical in appearance with the local grinding mills. The noria performs the function of moving water from an elevation to a higher elevation. In this it is similar to the saqiya and other pumps and its concept is similar to the modern hydraulic ram, which also uses the power of flowing water to pump some of the water out of the river. Unlike the water found in mills, a noria does not provide mechanical power to any other process. A few historical norias were hybrids, consisting of waterwheels assisted secondarily by animal power, a noria can raise water to somewhat less than its full height. The largest noria in the world, with a diameter of about 20 meters, is located in the Syrian city of Hama. Around 300 AD, the Romans replaced the wooden compartments with separate, attached ceramic pots that were tied to the outside of an open-framed wheel, norias were adopted from the Classical World by Muslim engineers, who made some improvements to the noria. In 1206, Al-Jazari introduced the use of the crankshaft in the noria and saqiya, Muslim engineers used norias to discharge water into aqueducts which carried the water to towns and fields
25.
New World
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The New World is one of the names used for the Earths Western Hemisphere, specifically the Americas. The term was coined by Florentine explorer Amerigo Vespucci, the Americas were also referred to as the fourth part of the world. New World are meaningful in historical context and for the purpose of distinguishing the worlds major ecozones, and to classify plant and animal species that originated therein. One can speak of the New World in a context, e. g. when discussing the voyages of Christopher Columbus. For lack of alternatives, the term is still useful to those discussing issues that concern the Americas. The term New World is used in a context, when one speaks of Old World. Biological taxonomists often attach the New World label to groups of species that are exclusively in the Americas, to distinguish them from their counterparts in the Old World. New World monkeys, New World vultures, New World warblers, the label is also often used in agriculture. Common Old World crops, and domesticated animals did not exist in the Americas until they were introduced by contact in the 1490s. Other famous New World crops include the cashew, cocoa, rubber, sunflower, tobacco, and vanilla, there are rare instances of overlap, e. g. In wine terminology, New World has a different definition, Vespucci was finally convinced when he proceeded on his mapping expedition through 1501-02, covering the huge stretch of coast of eastern Brazil. But this opinion is false, and entirely opposed to the truth, Vespuccis letter was a publishing sensation in Europe, immediately reprinted in several other countries. The Venetian explorer Alvise Cadamosto had used the term un altro mundo to refer to sub-Saharan Africa, however, this was merely a literary flourish, not a suggestion of a new fourth part of the world. Cadamosto was quite aware sub-Saharan Africa was firmly part of the African continent, the Italian-born Spanish chronicler Peter Martyr dAnghiera often shares credit with Vespucci for designating the Americas as a new world. Peter Martyr used the term Orbe Novo in the title of his history of the discovery of the Americas as a whole, a year later, Peter Martyr again refers to the marvels of the New Globe and the Western hemisphere. Christopher Columbus touched the continent of South America in his 1498 third voyage, in another letter, Columbus refers to having reached a new heavens and world and that he had placed another world under the dominion of the Kings of Spain. The Vespucci passage above applied the New World label to merely the continental landmass of South America, although the proceedings of the Toro-Burgos conferences are missing, it is almost certain that Vespucci articulated his recent New World thesis to his fellow navigators there. In English usage the term New World was problematic and only accepted relatively late, while it became generally accepted after Vespucci that Columbuss discoveries were not Asia but a New World, the geographic relationship between the two continents was still unclear
26.
Great Plains
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The region is known for supporting extensive cattle ranching and dry farming. The Canadian portion of the Plains is known as the Prairies, some geographers include some territory of northern Mexico in the Plains, but many stop at the Rio Grande. The term Great Plains is used in the United States to describe a sub-section of the even more vast Interior Plains physiographic division and it also has currency as a region of human geography, referring to the Plains Indians or the Plains States. There is no region referred to as the Great Plains in The Atlas of Canada, in terms of human geography, the term prairie is more commonly used in Canada, and the region is known as the Prairie Provinces or simply the Prairies. The region is about 500 mi east to west and 2,000 mi north to south, much of the region was home to American bison herds until they were hunted to near extinction during the mid/late 19th century. It has an area of approximately 500,000 sq mi, current thinking regarding the geographic boundaries of the Great Plains is shown by this map at the Center for Great Plains Studies, University of Nebraska–Lincoln. The term Great Plains, for the region west of about the 96th or 98th meridian, nevin Fennemans 1916 study, Physiographic Subdivision of the United States, brought the term Great Plains into more widespread usage. Before that the region was almost invariably called the High Plains, today the term High Plains is used for a subregion of the Great Plains. The Great Plains are the westernmost portion of the vast North American Interior Plains, during the Cretaceous Period, the Great Plains were covered by a shallow inland sea called the Western Interior Seaway. However, during the Late Cretaceous to the Paleocene, the seaway had begun to recede, leaving thick marine deposits. During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, traditionally, the spread of grasslands and the development of grazers have been strongly linked. The vast majority of animals became extinct in North America at the end of the Pleistocene. In general, the Great Plains have a variety of weather through the year, with very cold and harsh winters and very hot. Wind speeds are very high, especially in winter. Grasslands are among the least protected biomes, humans have converted much of the prairies for agricultural purposes or to create pastures. The Great Plains have dust storms mostly every year or so, the 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 in or more of rainfall per year and an area that receives less than 20 in. The region is subjected to extended periods of drought, high winds in the region may then generate devastating dust storms
27.
Tankhouse
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A tankhouse is a water tower enclosed by siding. Tankhouses were part of a domestic water system supplying the house and garden, developed before the advent of electricity. The system consisted of a windmill, a well and the tankhouse. The windmill pumped water from the well up into the tank at the top of the tankhouse, from where it flowed down under gravity pressure to the house, the system used no fuel or electricity, today it would be called green or eco-friendly. The tankhouse is sometimes called a pump-house, a well-house, a well-tower or just a water tower, but whatever it is called, it is a water tower that is enclosed by siding. The siding is what makes it a house, with interior space. Ordinary water towers, with a tank on top of a tower, are not tankhouses. The term is used for an unrelated structure in the copper-refining industry. Tankhouses are an important part of Californias historical heritage and the early material culture. The windmill, which stood over the well, was attached to the tower. Tankhouses became obsolete with the coming of deep, drilled wells and electric pumps in the countryside, almost all of the hand-dug wells have been filled in now, and most of the windmills have disappeared. The remaining tankhouses are a species, threatened by constant commercial, residential, industrial and agricultural development. Their numbers dwindle with each passing year, there are far more tankhouses in California than in any other state, and they most probably originated in California. A tankhouse was built in Mendocino, California, in 1857, Tankhouses can be found in most of the states 58 counties, wherever there was water not more than 50 feet or so below the surface. Probably after transcontinental and branch railroads were completed, tankhouses were built in western states, the midwest. There is an interesting but as yet not well documented cluster of tankhouses in the Texas hill country west of Austin, where German immigrants settled in the last half of the 19th century. They found no redwood, but there was plenty of limestone and it is possible that the tankhouse idea traveled from California to Texas, but it is also possible that the early German immigrants conceived the idea themselves or brought it with them from Germany. The cypress tanks, sometimes called cisterns in Texas, were exposed on top of the limestone towers
28.
Turbine
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A turbine is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating power when combined with a generator or producing thrust. A turbine is a turbomachine with at least one moving part called a rotor assembly, moving fluid acts on the blades so that they move and impart rotational energy to the rotor. Early turbine examples are windmills and waterwheels, gas, steam, and water turbines have a casing around the blades that contains and controls the working fluid. Modern steam turbines frequently employ both reaction and impulse in the unit, typically varying the degree of reaction and impulse from the blade root to its periphery. Benoit Fourneyron, a student of Claude Burdin, built the first practical water turbine. A working fluid contains potential energy and kinetic energy, the fluid may be compressible or incompressible. Several physical principles are employed by turbines to collect this energy, the resulting impulse spins the turbine and leaves the fluid flow with diminished kinetic energy. There is no change of the fluid or gas in the turbine blades, as in the case of a steam or gas turbine. Before reaching the turbine, the pressure head is changed to velocity head by accelerating the fluid with a nozzle. Pelton wheels and de Laval turbines use this process exclusively, Impulse turbines do not require a pressure casement around the rotor since the fluid jet is created by the nozzle prior to reaching the blades on the rotor. Newtons second law describes the transfer of energy for impulse turbines, Impulse turbines are most efficient for use in cases where the flow is low and the inlet pressure is high. Reaction turbines develop torque by reacting to the gas or fluids pressure or mass, the pressure of the gas or fluid changes as it passes through the turbine rotor blades. A pressure casement is needed to contain the working fluid as it acts on the stage or the turbine must be fully immersed in the fluid flow. The casing contains and directs the working fluid and, for water turbines, Francis turbines and most steam turbines use this concept. For compressible working fluids, multiple stages are usually used to harness the expanding gas efficiently. Newtons third law describes the transfer of energy for reaction turbines, reaction turbines are better suited to higher flow velocities or applications where the fluid head is low. In practice, modern designs use both reaction and impulse concepts to varying degrees whenever possible
29.
Torque
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Torque, moment, or moment of force is rotational force. Just as a force is a push or a pull. Loosely speaking, torque is a measure of the force on an object such as a bolt or a flywheel. For example, pushing or pulling the handle of a wrench connected to a nut or bolt produces a torque that loosens or tightens the nut or bolt, the symbol for torque is typically τ, the lowercase Greek letter tau. When it is called moment of force, it is denoted by M. The SI unit for torque is the newton metre, for more on the units of torque, see Units. This article follows US physics terminology in its use of the word torque, in the UK and in US mechanical engineering, this is called moment of force, usually shortened to moment. In US physics and UK physics terminology these terms are interchangeable, unlike in US mechanical engineering, Torque is defined mathematically as the rate of change of angular momentum of an object. The definition of states that one or both of the angular velocity or the moment of inertia of an object are changing. Moment is the term used for the tendency of one or more applied forces to rotate an object about an axis. For example, a force applied to a shaft causing acceleration, such as a drill bit accelerating from rest. By contrast, a force on a beam produces a moment, but since the angular momentum of the beam is not changing. Similarly with any force couple on an object that has no change to its angular momentum and this article follows the US physics terminology by calling all moments by the term torque, whether or not they cause the angular momentum of an object to change. The concept of torque, also called moment or couple, originated with the studies of Archimedes on levers, the term torque was apparently introduced into English scientific literature by James Thomson, the brother of Lord Kelvin, in 1884. A force applied at an angle to a lever multiplied by its distance from the levers fulcrum is its torque. A force of three newtons applied two metres from the fulcrum, for example, exerts the same torque as a force of one newton applied six metres from the fulcrum. More generally, the torque on a particle can be defined as the product, τ = r × F, where r is the particles position vector relative to the fulcrum. Alternatively, τ = r F ⊥, where F⊥ is the amount of force directed perpendicularly to the position of the particle, any force directed parallel to the particles position vector does not produce a torque
30.
Transmission (mechanics)
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A transmission is a machine in a power transmission system, which provides controlled application of the power. Often the term refers simply to the gearbox that uses gears and gear trains to provide speed. In British English, the term refers to the whole drivetrain, including clutch, gearbox, prop shaft, differential. In American English, however, the term more specifically to the gearbox alone. The most common use is in vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels. Such engines need to operate at a high rotational speed, which is inappropriate for starting, stopping. The transmission reduces the engine speed to the slower wheel speed. Transmissions are also used on bicycles, fixed machines. Often, a transmission has multiple gear ratios with the ability to switch between them as speed varies and this switching may be done manually or automatically. Directional control may also be provided, single-ratio transmissions also exist, which simply change the speed and torque of motor output. The output of the transmission is transmitted via the driveshaft to one or more differentials, while a differential may also provide gear reduction, its primary purpose is to permit the wheels at either end of an axle to rotate at different speeds as it changes the direction of rotation. Conventional gear/belt transmissions are not the mechanism for speed/torque adaptation. Alternative mechanisms include torque converters and power transformation, automatic transmissions use a valve body to shift gears using fluid pressures in conjunction with an ecm. Early transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engines, in support of pumping, milling, most modern gearboxes are used to increase torque while reducing the speed of a prime mover output shaft. This means that the shaft of a gearbox rotates at a slower rate than the input shaft. A gearbox can be set up to do the opposite and provide an increase in speed with a reduction of torque. Some of the simplest gearboxes merely change the rotational direction of power transmission. Many typical automobile transmissions include the ability to select one of several gear ratios, in this case, most of the gear ratios are used to slow down the output speed of the engine and increase torque
31.
Crankshaft
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A crankshaft—related to crank—is a mechanical part able to perform a conversion between reciprocating motion and rotational motion. In a reciprocating engine, it translates reciprocating motion of the piston into rotational motion, whereas in a reciprocating compressor, a Roman iron crank of yet unknown purpose dating to the 2nd century AD was excavated in Augusta Raurica, Switzerland. The 82.5 cm long piece has fitted to one end a 15 cm long bronze handle, the accompanying inscription is in Greek. The crank and connecting rod mechanisms of the other two archaeologically attested sawmills worked without a gear train, al-Jazari described a crank and connecting rod system in a rotating machine in two of his water-raising machines. His twin-cylinder pump incorporated a crankshaft, though the device was unnecessarily complex, the Italian physician Guido da Vigevano, planning for a new crusade, made illustrations for a paddle boat and war carriages that were propelled by manually turned compound cranks and gear wheels. In Renaissance Italy, the earliest evidence of a crank and connecting-rod is found in the sketch books of Taccola. A sound grasp of the motion involved is demonstrated a little later by Pisanello. One of the drawings of the Anonymous of the Hussite Wars shows a boat with a pair of paddle-wheels at each end turned by men operating compound cranks. Crankshafts were also described by Konrad Kyeser, Leonardo da Vinci and his wind-powered sawmill used a crankshaft to convert a windmills circular motion into a back-and-forward motion powering the saw. Corneliszoon was granted a patent for his crankshaft in 1597, large engines are usually multicylinder to reduce pulsations from individual firing strokes, with more than one piston attached to a complex crankshaft. Many small engines, such as found in mopeds or garden machinery, are single cylinder and use only a single piston. A crankshaft is subjected to stresses, potentially equivalent of several tonnes of force. The crankshaft is connected to the fly-wheel, the block, using bearings on the main journals. An engine loses up to 75% of its energy in the form of friction, noise and vibration in the crankcase. The remaining losses occur in the heat and blow by. The crankshaft has a linear axis about which it rotates, typically with several bearing journals riding on replaceable bearings held in the engine block. As the crankshaft undergoes a great deal of sideways load from each cylinder in an engine, it must be supported by several such bearings. This was a factor in the rise of V8 engines, with their shorter crankshafts, the long crankshafts of the latter suffered from an unacceptable amount of flex when engine designers began using higher compression ratios and higher rotational speeds
32.
The Fens
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The Fens, also known as the Fenland, is a naturally marshy region in eastern England. Most of the fens were drained several centuries ago, resulting in a flat, dry and it is one of the driest areas in England, thanks to a system of drainage channels and man-made rivers and automated pumping stations. A common misconception is that the fens are damp, in whole it occupies an area of nearly 1,500 sq mi. Most of the Fenland lies within a few metres of sea level, with the support of this drainage system, the Fenland has become a major arable agricultural region in Britain for grains and vegetables. The Fens are particularly fertile, containing half of the grade 1 agricultural land in England. The Fens have been referred to as the Holy Land of the English because of the monasteries, now churches and cathedrals, of Crowland, Ely, Peterborough. Other significant settlements in the Fens include Boston, Cambridge, Spalding, the Fens are very low-lying compared with the chalk and limestone uplands that surround them – in most places no more than 10 m above sea level. Indeed, as a result of drainage and the subsequent shrinkage of the peat fens, within the Fens there are a few hills, which have historically been called islands as they remained dry when the low-lying fens around them were flooded. The largest of the fen-islands is the Isle of Ely, on which the city of Ely was built. Some areas of the Fens were once permanently flooded, creating small lakes or meres, the rest of the Fenland was dedicated to pastoral farming, fishing, fowling and the harvesting of reeds or sedge for thatch. In this way, the medieval and early modern Fens stood in contrast to the rest of southern England, drainage in the Fenland consists of both river drainage and internal drainage of the land between the rivers. The internal drainage was organised by levels or districts, each of which includes the fen parts of one or several parishes, in the 17th century, the Great Level was divided into the North, Middle and South Levels for the purposes of administration and maintenance. In the 20th century, these levels have gained new boundaries, the South Level lies to the southeast of the Ouse Washes and surrounds Ely, as it did in the 17th century. The Middle Level currently lies between the Ouse Washes and the Nene, but historically lay between the Ouse Washes and Mortons Leam, a 15th-century canal which runs north of the town of Whittlesey. Deeping Fen, in the part of Lincolnshire, lies between the River Welland and the River Glen with its tributary the Bourne Eau. The Black Sluice District, much of which was known as the Lindsey Level when it was first drained in 1639, extends from the Glen and its water is carried through to the Haven at Boston. The above were all redrained at one time or another after the Civil War, at the end of the most recent glacial period, known in Britain as the Devensian, ten thousand years ago, Britain and continental Europe were joined by the ridge between Friesland and Norfolk. The topography of the bed of the North Sea indicates that the rivers of the part of eastern England flowed into the Rhine
33.
Cambridgeshire
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The city of Cambridge is the county town. It contains most of the known as Silicon Fen. Local government is divided between Cambridgeshire County Council and Peterborough City Council, which is a unitary authority. Cambridgeshire is noted as the site of Flag Fen in Fengate, one of the earliest-known Neolithic permanent settlements in the United Kingdom, compared in importance to Balbridie in Aberdeen, Scotland. A great quantity of archaeological finds from the Stone Age, the Bronze Age, most items were found in Isleham. Cambridgeshire was recorded in the Domesday Book as Grantbridgeshire, covering a large part of East Anglia, Cambridgeshire today is the result of several local government unifications. In 1965, these two counties were merged to form Cambridgeshire and the Isle of Ely. Under the Local Government Act 1972 this merged with the county to the west, Huntingdon, the resulting county was called simply Cambridgeshire. Since 1998, the City of Peterborough has been a separately administered area and it is associated with Cambridgeshire for ceremonial purposes such as Lieutenancy, and joint functions such as policing and the fire service. In 2002, the conservation charity Plantlife unofficially designated Cambridgeshires county flower as the Pasqueflower, the Cambridgeshire Regiment, the county-based army unit, fought in the Boer War of South Africa, the First World War and Second World War. Due to the flat terrain and proximity to the continent, during the Second World War the military built many airfields here for RAF Bomber Command, RAF Fighter Command. In recognition of this collaboration, the Cambridge American Cemetery and Memorial is located in Madingley and it is the only WWII burial ground in England for American servicemen who died during that event. Most English counties have nicknames for their people, such as a Tyke from Yorkshire, the traditional nicknames for people from Cambridgeshire are Cambridgeshire Camel or Cambridgeshire Crane, referring to the wildfowl that were once abundant in the fens. The term Fenners was often applied to those who come from the country to the north of Cambridge. Since the late 20th century, this term is considered to be derogatory and has been discouraged in use, original historical documents relating to Cambridgeshire are held by Cambridgeshire Archives and Local Studies. See also Geology of Cambridgeshire Large areas of the county are extremely low-lying, the highest point is in the village of Great Chishill at 146 m above sea level. Other prominent hills are Little Trees Hill and Wandlebury Hill in the Gog Magog Downs, Rivey Hill above Linton, Rowleys Hill, AWG plc is based in Huntingdon. The RAF has several stations in the Huntingdon and St Ives area, RAF Waterbeach,6 miles north of Cambridge, is a former RAF airfield, now used as an army barracks
34.
Sea level
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Mean sea level is an average level of the surface of one or more of Earths oceans from which heights such as elevations may be measured. A common and relatively straightforward mean sea-level standard is the midpoint between a low and mean high tide at a particular location. Sea levels can be affected by factors and are known to have varied greatly over geological time scales. The careful measurement of variations in MSL can offer insights into ongoing climate change, the term above sea level generally refers to above mean sea level. Precise determination of a sea level is a difficult problem because of the many factors that affect sea level. Sea level varies quite a lot on several scales of time and this is because the sea is in constant motion, affected by the tides, wind, atmospheric pressure, local gravitational differences, temperature, salinity and so forth. The easiest way this may be calculated is by selecting a location and calculating the mean sea level at that point, for example, a period of 19 years of hourly level observations may be averaged and used to determine the mean sea level at some measurement point. One measures the values of MSL in respect to the land, hence a change in MSL can result from a real change in sea level, or from a change in the height of the land on which the tide gauge operates. In the UK, the Ordnance Datum is the sea level measured at Newlyn in Cornwall between 1915 and 1921. Prior to 1921, the datum was MSL at the Victoria Dock, in Hong Kong, mPD is a surveying term meaning metres above Principal Datum and refers to height of 1. 230m below the average sea level. In France, the Marégraphe in Marseilles measures continuously the sea level since 1883 and it is used for a part of continental Europe and main part of Africa as official sea level. Elsewhere in Europe vertical elevation references are made to the Amsterdam Peil elevation, satellite altimeters have been making precise measurements of sea level since the launch of TOPEX/Poseidon in 1992. A joint mission of NASA and CNES, TOPEX/Poseidon was followed by Jason-1 in 2001, height above mean sea level is the elevation or altitude of an object, relative to the average sea level datum. It is also used in aviation, where some heights are recorded and reported with respect to sea level, and in the atmospheric sciences. An alternative is to base height measurements on an ellipsoid of the entire Earth, in aviation, the ellipsoid known as World Geodetic System 84 is increasingly used to define heights, however, differences up to 100 metres exist between this ellipsoid height and mean tidal height. The alternative is to use a vertical datum such as NAVD88. When referring to geographic features such as mountains on a topographic map, the elevation of a mountain denotes the highest point or summit and is typically illustrated as a small circle on a topographic map with the AMSL height shown in metres, feet or both. In the rare case that a location is below sea level, for one such case, see Amsterdam Airport Schiphol
35.
The Broads
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The Broads are a network of mostly navigable rivers and lakes in the English counties of Norfolk and Suffolk. The lakes, known locally as broads, were formed by the flooding of peat workings, the Broads, and some surrounding land, were constituted as a special area with a level of protection equivalent to a national park by the Norfolk and Suffolk Broads Act 1988. The Broads Authority, a statutory authority responsible for managing the area. The total area is 303 square kilometres, most of which is in Norfolk, there are seven rivers and 63 broads, mostly less than 4 metres deep. Thirteen broads are generally open to navigation, with a further three having navigable channels, some broads have navigation restrictions imposed on them in autumn and winter. Although the terms Norfolk Broads and Suffolk Broads are used to specific areas within the two counties respectively, the whole area is frequently referred to as the Norfolk Broads. Because of its navigation role the Broads Authority was established under its own legislation on 1 April 1989, the Broads Authority Act 2009, which was promoted through Parliament by the authority, is intended to improve public safety on the water. This followed a consultation which resulted in support from 79% of consultees, including unanimous support from the 14 UK national parks. Defra, the Government department responsible for the parks, also expressed it was content that the Authority would make its own decision on the matter. In response to this the Broads Authority has stated that its three purposes will remain in balance and that the branding is simply for marketing the National Park qualities of the Broads. The Broads are administered by the Broads Authority, Special legislation gives the navigation of the waterways equal status with the conservation and public enjoyment of the area. For many years the known as broads were regarded as natural features of the landscape. It was only in the 1960s that Dr Joyce Lambert proved that they were artificial features, in the Middle Ages the local monasteries began to excavate the peatlands as a turbary business, selling fuel to Norwich and Great Yarmouth. Norwich Cathedral took 320,000 tonnes of peat a year, then the sea levels began to rise, and the pits began to flood. Despite the construction of windpumps and dykes, the continued and resulted in the typical Broads landscape of today, with its reedbeds, grazing marshes. Various attempts were made to extend the navigable rivers, the longest-lasting was on the River Waveney, where an Act of Parliament passed on 17 March 1670 authorised improvements which included three locks, at Geldeston, Ellingham and Wainford. The head of navigation became a new staithe at Bungay, the new section was a private navigation which was not controlled by the Yarmouth Haven and Pier Commissioners, who had responsibility for the rest of the Broadland rivers. The next attempt was to extend navigation on the River Bure from Coltishall to Aylsham, five locks were built, to bypass mills, at Coltishall, Oxnead Lamas, Oxnead, Burgh and Aylsham
36.
Diesel fuel
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Diesel engines have found broad use as a result of higher thermodynamic efficiency and thus fuel efficiency. This is particularly noted where diesel engines are run at part-load, as their air supply is not throttled as in a petrol engine, to distinguish these types, petroleum-derived diesel is increasingly called petrodiesel. Ultra-low-sulfur diesel is a standard for defining diesel fuel with substantially lowered sulfur contents, as of 2016, almost all of the petroleum-based diesel fuel available in UK, Europe and North America is of a ULSD type. In the UK, diesel fuel for use is commonly abbreviated DERV, standing for diesel-engined road vehicle. In Australia diesel fuel is known as distillate, and in Indonesia, it is known as Solar. Diesel fuel originated from experiments conducted by German scientist and inventor Rudolf Diesel for his engine he invented in 1892. Diesel fuel is produced from various sources, the most common being petroleum, other sources include biomass, animal fat, biogas, natural gas, and coal liquefaction. Petroleum diesel, also called petrodiesel, or fossil diesel is the most common type of diesel fuel, synthetic diesel can be produced from any carbonaceous material, including biomass, biogas, natural gas, coal and many others. The raw material is gasified into synthesis gas, which after purification is converted by the Fischer–Tropsch process to a synthetic diesel, the process is typically referred to as biomass-to-liquid, gas-to-liquid or coal-to-liquid, depending on the raw material used. Paraffinic synthetic diesel generally has a content of sulfur and very low aromatics content, reducing unregulated emissions of toxic hydrocarbons, nitrous oxides. Fatty-acid methyl ester, more known as biodiesel, is obtained from vegetable oil or animal fats which have been transesterified with methanol. It can be produced from many types of oils, the most common being rapeseed oil in Europe, methanol can also be replaced with ethanol for the transesterification process, which results in the production of ethyl esters. FAME can be used pure in engines where the manufacturer approves such use, FAME as a fuel is specified in DIN EN14214 and ASTM D6751. Pure biodiesel has an energy content about 5–10% lower than petroleum diesel, the loss in power when using pure biodiesel is 5–7%. As FAME contains low levels of sulfur, the emissions of oxides and sulfates. Use of biodiesel also results in reductions of unburned hydrocarbons, carbon monoxide, CO emissions using biodiesel are substantially reduced, on the order of 50% compared to most petrodiesel fuels. The exhaust emissions of particulate matter from biodiesel have been found to be 30% lower than overall particulate matter emissions from petrodiesel, the exhaust emissions of total hydrocarbons are up to 93% lower for biodiesel than diesel fuel. Biodiesel also may reduce risks associated with petroleum diesel
37.
Southern Africa
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Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics, and including several countries. The term southern Africa or Southern Africa, generally includes Angola, Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, from a political perspective the region is said to be unipolar with South Africa as a first regional power. It is not used in political, economic or human geography contexts because this definition cuts Mozambique in two, the Southern African Development Community was established in 1980 to facilitate co-operation in the region. Comoros, Madagascar, Malawi, Mayotte, Mauritius, Mozambique, Réunion, Seychelles, Zambia, the Democratic Republic of the Congo and Tanzania, though more commonly reckoned in Central and Eastern Africa, respectively, are occasionally included in Southern Africa as they are SADC members. The terrain of Southern Africa is varied, ranging from forest, the region has both low-lying coastal areas, and mountains. While colonialism has left its mark on the development over the course of history, today poverty, corruption, the pursuit of economic and political stability is an important part of the regions goals, as demonstrated by the SADC. In terms of strength, South Africa is by far the dominant power of the region. South Africas GDP alone is many times greater than the GDPs of all countries in the region. Southern Africa has a diversity of ecoregions including grassland, bushveld, karoo, savannah. It has complex Plateaus that create massive mountain structures along the South African border, there are numerous environmental issues in Southern Africa, including air pollution and desertification. Southern Africa is home to cultures and people. It was once populated by San, Khoikhoi and Pygmies in widely dispersed concentrations, the process of colonization and settling resulted in a significant population of European and Asian descent in many southern African countries. These factors vary from country to country, for example, the Democratic Republic of Congo has favourable climatic and physical conditions, but performs far below its capacity in food provision due to political instability and poor governance. The Republic of South Africa is a food producer and exporter in the region. However this data might not fully capture the reality of a region with high urban populations, urban food security has been noted as an emerging area of development concern in the region, with recent data showing high levels of food insecurity amongst low-income households. In South Africa for example, while over 50% experience hunger, there is only limited data on the other Southern African countries. History of Southern Africa Sub-Saharan Africa Southern Africa
38.
Kenya
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Kenya, officially the Republic of Kenya, is a country in Africa and a founding member of the East African Community. Its capital and largest city is Nairobi and it is bordered by Tanzania to the south and southwest, Uganda to the west, South Sudan to the north-west, Ethiopia to the north and Somalia to the north-east. Kenya covers 581,309 km2, and had a population of approximately 48 million people in January 2017, Kenya has a warm and humid tropical climate on its Indian Ocean coastline. The climate is cooler in the grasslands around the capital city, Nairobi, and especially closer to Mount Kenya. Further inland are highlands in Central and Rift Valley regions where tea, in the West are Nyanza and Western regions, there is an equatorial, hot and dry climate which becomes humid around Lake Victoria, the largest tropical fresh-water lake in the world. This gives way to temperate and forested areas in the neighbouring western region. The north-eastern regions along the border with Somalia and Ethiopia are arid and semi-arid areas with near-desert landscapes, Kenya is known for its world class athletes in track and field and rugby. The African Great Lakes region, which Kenya is a part of, has been inhabited by humans since the Lower Paleolithic period, by the first millennium AD, the Bantu expansion had reached the area from West-Central Africa. Bantu and Nilotic populations together constitute around 97% of the nations residents, European and Arab presence in coastal Mombasa dates to the Early Modern period, European exploration of the interior began in the 19th century. The British Empire established the East Africa Protectorate in 1895, which starting in 1920 gave way to the Kenya Colony, Kenya obtained independence in December 1963. Following a referendum in August 2010 and adoption of a new constitution, Kenya is now divided into 47 semi-autonomous counties, the capital, Nairobi, is a regional commercial hub. The economy of Kenya is the largest by GDP in East, agriculture is a major employer, the country traditionally exports tea and coffee and has more recently begun to export fresh flowers to Europe. The service industry is also an economic driver. Additionally, Kenya is a member of the East African Community trading bloc, the Republic of Kenya is named after Mount Kenya. The origin of the name Kenya is not clear, but perhaps linked to the Kikuyu, Embu and Kamba words Kirinyaga, Kirenyaa, if so, then the British may not so much have mispronounced it, as misspelled it. In the 19th century, the German explorer Johann Ludwig Krapf was staying with the Bantu Kamba people when he first spotted the mountain. On asking for the name of the mountain, he was told Kĩ-Nyaa or Kĩĩma- Kĩĩnyaa probably because the pattern of black rock, the Agikuyu, who inhabit the slopes of Mt. Kenya, call it Kĩrĩma Kĩrĩnyaga in Kikuyu, which is quite similar to the Kamba name. Ludwig Krapf recorded the name as both Kenia and Kegnia believed by most to be a corruption of the Kamba version, others say that this was—on the contrary—a very precise notation of a correct African pronunciation /ˈkɛnjə/
39.
Non-governmental organization
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A non-governmental organization is a not-for-profit organization that is independent from states and international governmental organizations. They are usually funded by donations but some avoid formal funding altogether and are run primarily by volunteers, NGOs are highly diverse groups of organizations engaged in a wide range of activities, and take different forms in different parts of the world. Some may have charitable status, while others may be registered for tax exemption based on recognition of social purposes, others may be fronts for political, religious, or other interests. The number of NGOs worldwide is estimated to be 3.7 million, India is estimated to have had around 2 million NGOs in 2009, just over one NGO per 600 Indians, and many times the number of primary schools and primary health centres in India. China is estimated to have approximately 440,000 officially registered NGOs, NGOs are difficult to define, and the term NGO is not always used consistently. In some countries the term NGO is applied to an organization that in another country would be called an NPO, there are many different classifications of NGO in use. The most common focus is on orientation and level of operation, an NGOs orientation refers to the type of activities it takes on. These activities might include human rights, environmental, improving health, an NGOs level of operation indicates the scale at which an organization works, such as local, regional, national, or international. The term non-governmental organization was first coined in 1945, when the United Nations was created, later the term became used more widely. One characteristic these diverse organizations share is that their non-profit status means they are not hindered by short-term financial objectives. Accordingly, they are able to devote themselves to issues which occur across longer time horizons, such as change, malaria prevention. Public surveys reveal that NGOs often enjoy a degree of public trust. NGO/GRO types can be understood by their orientation and level of how they operate, charitable orientation often involves a top-down paternalistic effort with little participation by the beneficiaries. It includes NGOs with activities directed toward meeting the needs of the poor people, in the classical community development project, participation begins with the need definition and continues into the planning and implementation stages. There is maximum involvement of the beneficiaries with NGOs acting as facilitators, community-based organizations arise out of peoples own initiatives. They can be responsible for raising the consciousness of the poor, helping them to understand their rights in accessing needed services. City-wide organizations include organizations such as chambers of commerce and industry, coalitions of business, ethnic or educational groups, national NGOs include national organizations such as the YMCAs/YWCAs, professional associations and similar groups. Some have state and city branches and assist local NGOs and they can be responsible for funding local NGOs, institutions and projects and implementing projects
40.
East Africa
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East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. The first five are included in the African Great Lakes region. Burundi and Rwanda are sometimes considered to be part of Central Africa. Djibouti, Eritrea, Ethiopia and Somalia – collectively known as the Horn of Africa, Comoros, Mauritius and Seychelles – small island nations in the Indian Ocean. Réunion and Mayotte – French overseas territories also in the Indian Ocean, Mozambique and Madagascar – often considered part of Southern Africa, on the eastern side of the sub-continent. Madagascar has close ties to Southeast Asia and the islands of the Indian Ocean. Malawi, Zambia and Zimbabwe – often also included in Southern Africa, Egypt, Sudan and South Sudan – collectively part of the Nile Valley. Situated in the portion of the continent, and Egypt. Also members of the Common Market for Eastern and Southern Africa free trade area, the geography of East Africa is often stunning and scenic. Shaped by global plate tectonic forces that have created the East African Rift, East Africa is the site of Mount Kilimanjaro and Mount Kenya and it also includes the worlds second largest freshwater lake Lake Victoria, and the worlds second deepest lake Lake Tanganyika. The climate of East Africa is rather atypical of equatorial regions, in fact, on the coast of Somaliland and Puntland, many years can go by without any rain whatsoever. Unusually, most of the falls in two distinct wet seasons, one centred on April and the other in October or November. Annual rainfall here ranges from over 1,600 millimetres on the slopes to around 1,250 millimetres at Addis Ababa and 550 millimetres at Asmara. In the high rainfall can be over 2,500 millimetres. Temperatures in East Africa, except on the hot and generally humid coastal belt, are moderate, with maxima of around 25 °C, at altitudes of above 2,500 metres, frosts are common during the dry season and maxima typically about 21 °C or less. The unique geography and apparent suitability for farming made East Africa a target for European exploration, exploitation and colonialization in the nineteenth century, today, tourism is an important part of the economies of Kenya, Tanzania, Seychelles, and Uganda. The easternmost point of the continent, that is Ras Hafun in Somalia, is of archaeological, historical and economical importance, there are differing theories on whether there was a single exodus or several, a multiple dispersal model involves the Southern Dispersal theory. A growing number of researchers suspect that North Africa was instead the home of the modern humans who first trekked out of the continent
41.
Rope pump
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A rope pump is a kind of pump where a loose hanging rope is lowered down into a well and drawn up through a long pipe with the bottom immersed in water. On the rope, round disks or knots matching the diameter of the pipe are attached which pull the water to the surface and it is commonly used in developing countries for both community supply and self-supply and can be installed on boreholes or hand-dug wells. A rope pump is a type of pump of which the main or most visible component is a piece of rope. Rope pumps are used in developing areas, the most common design of which uses PVC pipe. Rope pumps are cheap to build and easy to maintain, one design of rope pump using a solar-powered rope pump can pump 3,000 litres to 15 meters per day using an 80 watt solar panel. Rope pumps can be powered by low speed engines, electricity, human energy, wind. Chain or washer pumps were used by the Chinese over 1000 years ago and he began at Burkina Faso in Africa, continued to Tunisia, Thailand and Gambia among others. In Nicaragua, the technology was rapidly disseminated over the whole country and it is also used in other parts of Central America with over 25,000 pumps installed to date. In Africa the rope pump is now being used with solar energy, by the end of 2009 more than 4 million people in 20 countries worldwide were using rope pumps for domestic and irrigation water. The original rope pumps used knots along the length but can be made with flexible or rigid valves on the rope instead of knots. Alternatively they may use only rope, simply relying on the water clinging to the rope as it is pulled to the surface. Flexible valves can be made from cut pieces of bicycle wheel tubing, the valves are positioned approximately 20 cm apart on the rope. One disadvantage of flexible valve rope pumps is that they must be sized and thickness for different types, sizes. Rigid valves using plastic or metal washers that fit tightly into the PVC pipe as the rope is dragged through are also used, if the fit is tight, the washers can be spaced up to half a meter apart. The deeper the well, the smaller the pipe inner diameter must be and these rope pumps are often worked with a hand crank Valves can also be made from knots in the rope itself. Valveless pumps rely on friction with water clinging to the rope and it is a less efficient design but is simpler to construct than the other rope pumps. Rope pump technology is in the domain and there are no patents pending on it. Chain pump Wind pump rope pump site Rope pump Lambdon, Robert, how to Make a Rope and Washer Pump
42.
Nicaragua
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Nicaragua, officially the Republic of Nicaragua, is the largest country in the Central American isthmus. Nicaraguas capital, Managua, is the countrys largest city and the third-largest city in Central America, the multi-ethnic population of six million includes indigenous peoples, Europeans, Africans, and Asians. Native tribes on the eastern coast speak their own languages, the Spanish Empire conquered the region in the 16th century. Nicaragua gained independence from Spain in 1821, since its independence, Nicaragua has undergone periods of political unrest, dictatorship, and fiscal crisis—the most notable causes that led to the Nicaraguan Revolution of the 1960s and 1970s. Nicaragua is a democratic republic. The biological diversity, warm climate and active volcanoes make Nicaragua an increasingly popular tourist destination. The name Nicaragua was coined by Spanish colonists based on the name Nicarao, when Spaniard Gil González Dávila came to Nicaragua in 1521 he found in the areas between Rivas and San Jorge the first pre-Columbian natives of Nicaragua. At the time the city was called Quauhcapolca and the cacique leaders name was Macuilmiquiztli. The Pipil migrated to Nicaragua from central Mexico after 500 BC, meanwhile, the Caribbean coast of Nicaragua was inhabited by other peoples, mostly Chibcha language groups. They had coalesced in Central America and migrated also to present-day northern Colombia and they lived a life based primarily on hunting and gathering. In 1502, Christopher Columbus became the first European known to have reached what is now Nicaragua as he sailed southeast toward the Isthmus of Panama, on his fourth voyage, Columbus explored the Miskito Coast on the Atlantic side of Nicaragua. The Spanish attempted to convert all three tribes to Christianity, Nicaragua and Nicarao and their people converted, but Dirangen, however, did not, the first attempt to conquer what is now known as Nicaragua was by Gil González Dávila, who arrived in Panama in January 1520. The first Spanish permanent settlements were founded in 1524, conquistador Francisco Hernández de Córdoba founded two of Nicaraguas principal towns in 1524, Granada on Lake Nicaragua was the first settlement, followed by León at a location west of Lake Managua. Córdoba soon built defenses for the cities and fought against incursions by other conquistadors, Córdoba was later publicly beheaded following a power struggle with Pedro Arias Dávila. His tomb and remains were discovered in 2000 in the ruins of León Viejo, the clashes among Spanish forces did not impede their destruction of the indigenous people and their culture. The series of battles came to be known as the War of the Captains, Pedro Arias Dávila was a winner, although he had lost control of Panama, he moved to Nicaragua and successfully established his base in León. Through adroit diplomatic machinations, he became the first governor of the colony, many indigenous people died as a result of new infectious diseases, compounded by neglect by the Spaniards, who controlled their subsistence. In 1610, the Momotombo volcano erupted, destroying the capital and it was rebuilt northwest of what is now known as the ruins of Old León
43.
Centrifugal pump
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Centrifugal pumps are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. Centrifugal pumps are used to transport fluids by the conversion of kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor, the fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber, from where it exits. Common uses include water, sewage, petroleum and petrochemical pumping, the reverse function of the centrifugal pump is a water turbine converting potential energy of water pressure into mechanical rotational energy. True centrifugal pumps were not developed until the late 17th century, the curved vane was introduced by British inventor John Appold in 1851. Like most pumps, a centrifugal pump converts rotational energy, often from a motor, a portion of the energy goes into kinetic energy of the fluid. The fluid gains both velocity and pressure while passing through the impeller, the doughnut-shaped diffuser, or scroll, section of the casing decelerates the flow and further increases the pressure. A consequence of Newton’s second law of mechanics is the conservation of the momentum which is of fundamental significance to all turbomachines. Accordingly, the change of the momentum is equal to the sum of the external moments. Angular momentums ρ×Q×r×cu at inlet and outlet, an external torque M and this is an important role in old academic, this rule was helpful to detail Eq. become Eq. and wide explained how the pump works. Fig 2.3 shows triangle velocity of forward curved vanes impeller and it illustrates rather clearly energy added to the flow inversely change upon flow rate Q. Power is more commonly expressed as kilowatts or horsepower, the value for the pump efficiency, η p u m p, may be stated for the pump itself or as a combined efficiency of the pump and motor system. Vertical centrifugal pumps are also referred to as cantilever pumps and they utilize a unique shaft and bearing support configuration that allows the volute to hang in the sump while the bearings are outside the sump. This style of pump uses no stuffing box to seal the shaft, a common application for this style of pump is in a parts washer. In the mineral industry, or in the extraction of oilsand, froth is generated to separate the rich minerals or bitumen from the sand, froth contains air that tends to block conventional pumps and cause loss of prime. Over history, industry has developed different ways to deal with this problem, in the pulp and paper industry holes are drilled in the impeller. Air escapes to the back of the impeller and a special expeller discharges the air back to the suction tank, the impeller may also feature special small vanes between the primary vanes called split vanes or secondary vanes. Some pumps may feature an eye, an inducer or recirculation of pressurized froth from the pump discharge back to the suction to break the bubbles
44.
Waterladder pump
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A waterladder pump, water ladder, dragon spine, dragon wheel or rahad is a low lift pump which is composed of sprockets that move a chain with paddles over a trough. Water is pumped as the push the water up the trough. The water ladder, as many low lift pumps, is used for irrigation purposes. It is currently used by farmers in south-east Asia. The water ladder was built as an alternative to the wheel to get around the problem that to lift water to a greater height. This is possible as all the components can be built from local resources, such as wood, as mentioned before, the pump only allows the lifting of water over a small height. This makes it unsuitable to water drainage or irrigation over larger height differences or many other pumping applications besides drainage and irrigation
45.
Tjasker
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The tjasker is a small type of windmill used solely for drainage purposes. The tjasker is commonly known as a typical Frisian windmill though it is found in other Dutch provinces. The tjasker seems to have been developed somewhere towards the end of the 16th century, the total number of tjaskers at their peak is also unclear. The mills were used to small plots of land but also found their use at peat digging sites as they could be easily moved. Millwright R. W. Dijksma of Giethoorn was well known for his tjasker building and he constructed 400 to 500 tjaskers between 1910 and 1945, though these numbers include hand powered Archimedes screws. The last tjasker was erected in 1935 and by 1963 there were three left in the Netherlands. In that year emerging views on nature preservation and cultural history resulted in the installation of a brand new tjasker in De Weerribben, since then, several other new tjaskers have been built, to pump water into wetlands and as cultural monuments. Currently, there are 28 tjaskers in the Netherlands and six tjaskers in Germany, the tjasker has only one wooden millshaft on which all machinery is carried. This shaft is inclined at an angle of approximately 30° and supported in a wooden frame, on the lower end it carries the Archimedean screw which is partly submerged in water. The screw doesnt rotate in a pipe but has a fixed encasing which simplifies the design further, the top end of the shaft carries the Common sails with a span of approximately 5 to 6 meters. In some cases wooden slats are used instead of sail cloth, the mill can be stopped using a band brake on the brake disk which is fitted on the shaft behind the top bearing. The entire mill has to be rotated to face the wind, to accomplish this two types of tjasker have developed. In the first type, known as paaltjasker, the mill is supported on, the Archimedes screw pumps water from the outer circular ditch to a central circular ditch or pool. The screw moves in a circle when the mill is turned so these circular ditches enable the mill to function in whatever direction it is pointing, the second type of tjasker, the boktjasker, is not balanced on a central post but supported on a trestle. The lower submerged support is fixed, the mill is rotated around this point, here the trestle is commonly equipped with rollers or wheels on a fixed ring to make winding easier. In this method of construction the Archimedes screw takes water from a central pool, water can be taken to the central pool by a pipe or a gap in the circular ditch. A boktjasker is more or less fixed to its location, a third type of tjasker has been rediscovered from old drawings. It has a tail keeping the mill facing in the wind, after having built a functional model the reconstruction of a full sized staarttjasker is now planned
46.
Windmill sail
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Windmills are powered by their sails. Sails are found in different designs, from primitive common sails to the patent sails. The jib sail is found in Mediterranean countries and consists of a triangle of cloth wound round a spar. The mill must be stopped in order to adjust the reefing of the sail, though rare in the UK, at least two windmills are known to have had jib sails. The common sail is the simplest form of sail, in medieval mills, the sailcloth was wound in and out of a ladder-type arrangement of sails. Medieval sails could be constructed with or without outer sailbars, post-medieval mill sails have a lattice framework over which the sailcloth is spread. There are various reefs for the different spread of sails, these are full sail, dagger point, sword point, the mill must be stopped in order to adjust the reefing of the sail. Spring sails were invented by Scottish millwright Andrew Meikle in 1772, the sail is divided into a number of bays, each having a number of shutters. All the shutters are joined together by a bar. Although automatic in operation, the mill must be stopped in order to adjust the reefing of the sail, roller reefing sails were invented by Stephen Hooper in 1789. As with spring sails, the sail is divided into a number of bays, the cloth is extended or retracted by a rod and lever system, and connected with a shutter bar on each sail. Adjustment of the roller reefing sail can be made without stopping the mill and this type of sail was popular in Yorkshire, although the only remaining mill with roller reefing sails intact is Ballycopeland Windmill in Northern Ireland. Patent sails were invented by William Cubitt in 1807 and they combine the shutters of the spring sail with automatic adjustment of the roller reefing sail. Their construction is similar to that of the spring sail, adjustment of patent sails can be made without stopping the mill. Air brakes In 1860, the English millwright Catchpole fitted an automatic air brake to the ends of patent sails and these were longitudinal shutters at the tip of each sail, which opened up if the wind got too strong, thus slowing the sail. Spring patent sails have a spring to enable each sail to be adjusted individually, the system was not a common one. In the Netherlands, the common sail predominates, Dekker / Van Bussel system The Dutch millwright A. J. Dekker improved on the efficiency of the common sail. The stock is given an airfoil shape by completely covering it with galvanised steel plates, dekkerised sails provide enough surface area to be able to work the mill with no sailcloth spread if the wind is strong enough
