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Windmills Completed In 1829
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 z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornell University
Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to teach and make contributions in all fields of knowledge—from the classics to the sciences, and from the theoretical to the applied. These ideals, unconventional for the time, are captured in Cornell's founding principle, a popular 1868 quotation from founder Ezra Cornell: "I would found an institution where any person can find instruction in any study." Cornell is ranked among the top global universities. The university is organized into seven undergraduate colleges and seven graduate divisions at its main Ithaca campus, with each college and division defining its specific admission standards and academic programs in near autonomy. The university also administers three satellite campuses, two in New York City and one in Education City, Qatar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography In Medieval Islam
Medieval Islamic geography and cartography refer to the study of geography and cartography in the Muslim world during the Islamic Golden Age (variously dated between the 8th century and 16th century). Muslim scholars made advances to the map-making traditions of earlier cultures, particularly the Hellenistic geographers Ptolemy and Marinus of Tyre, combined with what explorers and merchants learned in their travels across the Old World ( Afro-Eurasia). Islamic geography had three major fields: exploration and navigation, physical geography, and cartography and mathematical geography. Islamic geography reached its apex with Muhammad al-Idrisi in the 12th century. History Islamic geography began in the 8th century, influenced by Hellenistic geography, combined with what explorers and merchants learned in their travels across the Old World ( Afro-Eurasia). Muslim scholars engaged in extensive exploration and navigation during the 9th-12th centuries, including journeys across the Mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umar Ibn Al-Khattab
ʿUmar ibn al-Khaṭṭāb ( ar, عمر بن الخطاب, also spelled Omar, ) was the second Rashidun caliph, ruling from August 634 until his assassination in 644. He succeeded Abu Bakr () as the second caliph of the Rashidun Caliphate on 23 August 634. Umar was a senior companion and father-in-law of the Islamic prophet Muhammad. He was also an expert Muslim jurist known for his pious and just nature, which earned him the epithet ''al-Fārūq'' ("the one who distinguishes (between right and wrong)"). Umar initially opposed Muhammad, his distant Qurayshite kinsman and later son-in-law. Following his conversion to Islam in 616, he became the first Muslim to openly pray at the Kaaba. Umar participated in almost all battles and expeditions under Muhammad, who bestowed the title ''al-Fārūq'' ('the Distinguisher') upon Umar, for his judgements. After Muhammad's death in June 632, Umar pledged allegiance to Abu Bakr () as the first caliph and served as the closest adviser t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
