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Wind Turbines
A wind turbine is a device that converts the kinetic energy of wind into electrical energy. Hundreds of thousands of large turbines, in installations known as wind farms, now generate over 650 gigawatts of power, with 60 GW added each year. Wind turbines are an increasingly important source of intermittent renewable energy, and are used in many countries to lower energy costs and reduce reliance on fossil fuels. One study claimed that, wind had the "lowest relative greenhouse gas emissions, the least water consumption demands and the most favorable social impacts" compared to photovoltaic, hydro, geothermal, coal and gas energy sources. Smaller wind turbines are used for applications such as battery charging for auxiliary power for boats or caravans, and to power traffic warning signs. Larger turbines can contribute to a domestic power supply while selling unused power back to the utility supplier via the electrical grid. Wind turbines are manufactured in a wide range of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windmills D1-D4 (Thornton Bank)
A windmill is a structure that converts wind power into rotational energy using vanes called sails or blades, specifically to mill grain (gristmills), but the term is also extended to windpumps, wind turbines, and other applications, in some parts of the English speaking world. The term wind engine is sometimes used to describe such devices. Windmills were used throughout the high medieval and early modern periods; the horizontal or panemone windmill first appeared in Persia during the 9th century, and the vertical windmill first appeared in northwestern Europe in the 12th century. Regarded as an icon of Dutch culture, there are approximately 1,000 windmills in the Netherlands today. Forerunners Wind-powered machines may have been known earlier, but there is no clear evidence of windmills before the 9th century. Hero of Alexandria (Heron) in first-century Roman Egypt described what appears to be a wind-driven wheel to power a machine.Dietrich Lohrmann, "Von der östlichen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caravan (towed Trailer)
A caravan, travel trailer, camper, tourer or camper trailer is a trailer towed behind a road vehicle to provide a place to sleep which is more comfortable and protected than a tent (although there are fold-down trailer tents). It provides the means for people to have their own home on a journey or a vacation, without relying on a motel or hotel, and enables them to stay in places where none is available. However, in some countries campers are restricted to designated sites for which fees are payable. Caravans vary from basic models which may be little more than a tent on wheels to those containing several rooms with all the furniture and furnishings and equipment of a home. Construction of the solid-wall trailers can be made of metal or fiberglass. Travel trailers are used principally in North America, Europe, Australia and New Zealand. History In Europe, the origins of travel trailers and caravanning can be traced back to the travelling Romani people, and showmen who spent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Ages
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire and transitioned into the Renaissance and the Age of Discovery. 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 itself subdivided into the Early, High, and Late Middle Ages. Population decline, counterurbanisation, the collapse of centralized authority, invasions, and mass migrations of tribes, which had begun in late antiquity, continued into the Early Middle Ages. 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 7th century, North Africa and the Middle East—most recently part of the Ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Donald Routledge Hill
Donald Routledge Hill (6 August 1922 – 30 May 1994)D. A. King, “In Memoriam: Donald Routledge Hill (1922-1994)”, ''Arabic Sciences and Philosophy,'' Volume 5 / Issue 02 / September 1995, pp 297-302 was a British engineer and historian of science and technology best known for his translation of ''The Book of Knowledge of Ingenious Mechanical Devices'' of the Muslim engineer Ismail al-Jazari.Hill Donald(1993) Life and work Born in London, after secondary school Hill served in the British army, in the Royal Engineers from 1941 to 1946. Two years he served in the Eighth Army in North Africa until he was wounded in action in Italy. Back in England he studied Engineering at the London University, obtaining his engineering degree in 1949. In 1964 he obtained his M.Litt in Islamic History at the University of Durham, and in 1970 his PhD from the University of London. Late 1940s Hill started his career working for the Iraq Petroleum Company in Lebanon, Syria and Qatar. Back in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gristmill
A gristmill (also: grist mill, corn mill, flour mill, feed mill or feedmill) grinds cereal grain into flour and middlings. The term can refer to either the grinding mechanism or the building that holds it. Grist is grain that has been separated from its chaff in preparation for grinding. History Early history The Greek geographer Strabo reports in his ''Geography'' a water-powered grain-mill to have existed near the palace of king Mithradates VI Eupator at Cabira, Asia Minor, before 71 BC. The early mills had horizontal paddle wheels, an arrangement which later became known as the " Norse wheel", as many were found in Scandinavia. The paddle wheel was attached to a shaft which was, in turn, attached to the centre of the millstone called the "runner stone". The turning force produced by the water on the paddles was transferred directly to the runner stone, causing it to grind against a stationary "bed", a stone of a similar size and shape. This simple arrangement r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windmill Sail
Windmills are powered by their sails. Sails are found in different designs, from primitive common sails to the advanced patent sails. Jib sails The jib sail is found in Mediterranean countries and consists of a simple 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 (St Mary's, Isle of Scilly and Cann Mills, Melbury Abbas). Image:Windmill Antimahia Kos.jpg, Jib sails Image:Sobreiro.jpg, More fully spread Image:Spanish Mill, St Mary's.jpg, St Mary's, Isles of Scilly File:Cann Mill, Melbury Abbas.jpg, Cann Mills, Melbury Abbas Common 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 vario ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drive Shaft
A drive shaft, driveshaft, driving shaft, tailshaft ( Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them. As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, while avoiding too much additional weight as that would in turn increase their inertia. To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or more universal joints, jaw couplings, or rag joints, and sometimes a splined joint or prismatic joint. History The term ''driveshaft'' first appeared during the mid-1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panemone Windmill
A panemone windmill is a type of vertical axis wind turbine. It has a rotating axis positioned vertically, while the wind-catching blades move parallel to the wind. By contrast, the shaft of a horizontal axis wind turbine (HAWT) points into the wind while its blades move at right-angles to the wind's thrust. That is, a panemone primarily uses drag whereas the blades of a HAWT use lift. Historically the earliest known wind machine was made by the Persians and it was the panemone design, consisting of a wall, with slits, surrounding a vertical axle containing four to eight fabric sails. As the wind blew, the sails would turn the axle, which was in turn connected to grain grinders or some form of water transportation device (though little is known of the actual details of such methods). History The earliest recorded windmill design found was Persian in origin, and was invented sometime around 700–900 AD. This design was the panemone, with vertical lightweight wooden s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persia
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmenistan to the north, by Afghanistan and Pakistan to the east, and by the Gulf of Oman and the Persian Gulf to the south. It covers an area of , making it the 17th-largest country. Iran has a population of 86 million, making it the 17th-most populous country in the world, and the second-largest in the Middle East. Its largest cities, in descending order, are the capital Tehran, Mashhad, Isfahan, Karaj, Shiraz, and Tabriz. The country is home to one of the world's oldest civilizations, beginning with the formation of the Elamite kingdoms in the fourth millennium BC. It was first unified by the Medes, an ancient Iranian people, in the seventh century BC, and reached its territorial height in the sixth century BC, when Cyrus the Great founded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sistan
Sistān ( fa, سیستان), known in ancient times as Sakastān ( fa, سَكاستان, "the land of the Saka"), is a historical and geographical region in present-day Eastern Iran ( Sistan and Baluchestan Province) and Southern Afghanistan ( Nimruz, Helmand, Kandahar). Largely desert, the region is bisected by the Helmand River, the largest river in Afghanistan, which empties into the Hamun Lake that forms part of the border between the two countries. Etymology Sistan derives its name from ''Sakastan'' ("the land of the Saka"). The Sakas were a Scythian tribe which from the 2nd century BC to the 1st century migrated to the Iranian Plateau and Indus valley, where they carved a kingdom known as the Indo-Scythian Kingdom. In the Bundahishn, a Zoroastrian scripture written in Pahlavi, the province is called "Seyansih". After the Arab conquest of Iran, the province became known as Sijistan/Sistan. The more ancient Old Persian name of the region - prior to Saka dominanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hero Of Alexandria
Hero of Alexandria (; grc-gre, Ἥρων ὁ Ἀλεξανδρεύς, ''Heron ho Alexandreus'', also known as Heron of Alexandria ; 60 AD) was a Greek mathematician and engineer who was active in his native city of Alexandria, Roman Egypt. He is often considered the greatest experimenter of antiquity and his work is representative of the Hellenistic scientific tradition. Hero published a well-recognized description of a steam-powered device called an '' aeolipile'' (sometimes called a "Hero engine"). Among his most famous inventions was a windwheel, constituting the earliest instance of wind harnessing on land. He is said to have been a follower of the atomists. In his work ''Mechanics'', he described pantographs. Some of his ideas were derived from the works of Ctesibius. In mathematics he is mostly remembered for Heron's formula, a way to calculate the area of a triangle using only the lengths of its sides. Much of Hero's original writings and designs have been lost, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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