Mariana Trench ( World's Deepest Part )

The Mariana Trench or Marianas Trench[1] is the deepest part of the world's oceans. It is located in the western Pacific Ocean, to the east of the Mariana Islands. The trench is about 2,550 kilometres (1,580 mi) long with an average width of 69 kilometres (43 mi). It reaches a maximum-known depth of 10,994 m (± 40 m) or 6.831 mi (36,070 ± 131 ft) at a small slot-shaped valley in its floor known as the Challenger Deep, at its southern end,[2] although some unrepeated measurements place the deepest portion at 11,034 metres (36,201 ft).[3]

At the bottom of the trench the water column above exerts a pressure of 1,086 bars (15,750 psi) (over 1000 times the standard atmospheric pressure at sea level). At this pressure, the density of water is increased by 4.96%, making 95 litres of water under the pressure of the Challenger Deep contain the same mass as 100 litres at the surface. The temperature at the bottom is 1 to 4 °C.[4]

The trench is not the part of the seafloor closest to the center of the Earth. This is because the Earth is not a perfect sphere; its radius is about 25 kilometres (16 mi) less at the poles than at the equator.[5] As a result, parts of the Arctic Ocean seabed are at least 13 kilometres (8.1 mi) closer to the Earth's center than the Challenger Deep seafloor.

Xenophyophores have been found in the trench by Scripps Institution of Oceanography researchers at a record depth of 10.6 km (6.6 mi) below the sea surface.[6] On 17 March 2013, researchers reported data that suggested microbial life forms thrive within the trench.[7][8]  The Mariana Trench is part of the Izu-Bonin-Mariana subduction system that forms the boundary between two tectonic plates. In this system, the western edge of one plate, the Pacific Plate, is subducted (i.e., thrust) beneath the smaller Mariana Plate that lies to the west. Crustal material at the western edge of the Pacific Plate is some of the oldest oceanic crust on earth (up to 170 million years old), and is therefore cooler and more dense; hence its great height difference relative to the higher-riding (and younger) Mariana Plate. The deepest area at the plate boundary is the Mariana Trench proper.

The movement of the Pacific and Mariana plates is also indirectly responsible for the formation of the Mariana Islands. These volcanic islands are caused by flux melting of the upper mantle due to release of water that is trapped in minerals of the subducted portion of the Pacific Plate.

Grand Central Terminal ( world's largest station )

Grand Central Terminal (GCT; also referred to as Grand Central Station or simply as Grand Central) is a commuter (and former intercity) railroad terminal at 42nd Street and Park Avenue in Midtown Manhattan in New York City, United States. Built by and named for the New York Central and Hudson River Railroad in the heyday of American long-distance passenger rail travel, it covers 48 acres (19 ha) and has 44 platforms, more than any other railroad station in the world. Its platforms, all below ground, serve 41 tracks on the upper level and 26 on the lower, though the total number of tracks along platforms and in rail yards exceeds 100.

The terminal serves commuters traveling on the Metro-North Railroad to Westchester, Putnam, and Dutchess counties in New York State, and Fairfield and New Haven counties in Connecticut. Until 1991, the terminal served Amtrak, which moved to nearby Pennsylvania Station upon completion of the Empire Connection. The East Side Access project is underway to bring Long Island Rail Road service to the terminal.

Grand Central Terminal has intricate designs both on its inside and outside. In addition, it contains a vast interior main concourse. The terminal is one of the world's most visited tourist attractions, with 21.9 million visitors in 2013.

Unlike other Metro-North stations, Grand Central Terminal is not owned by the Metropolitan Transportation Authority, but by a private company known as Midtown TDR Ventures.

Naming

Although the terminal has been officially called "Grand Central Terminal" since the present structure opened, it has "always been more colloquially and affectionately known as Grand Central Station", a name of one of the earlier railroad stations on the same site.[3][4][N 1] "Grand Central Station" is the name of the nearby U.S. Post Office station at 450 Lexington Avenue,[5] but may also refer to the Grand Central – 42nd Street subway station that is located next to the terminal.

Layout

Grand Central Terminal, on 42nd Street

Diagram of the Upper Level of the main Terminal (1939)

The tracks are numbered according to their location in the terminal building. The upper-level tracks are numbered 11 to 42 east to west. Tracks 22 and 31 were removed in the late 1990s to build concourses for Grand Central North. Track 12 was removed to expand the platform between tracks 11 and 13 and track 14 is only used for loading a garbage train. The lower level has 27 tracks, numbered 100 to 126, east to west; currently, only tracks 102–112, and 114–116 are used for passenger service. Odd-numbered tracks are usually on the east side (right side facing north) of the platform; even-numbered tracks on the west.

Grand Central Terminal has both monumental spaces and meticulously crafted detail, especially on its facade.[6] In a February 2013 BBC News article, historian David Cannadine described it as one of the most majestic buildings of the twentieth century.[7] In 2013, Grand Central Terminal hosted 21.6 million visitors, putting it among the ten most-visited tourist attractions in the world.[8]

Its interior has restaurants, such as the Oyster Bar, and various fast food outlets surrounding the Dining Concourse on the level below the Main Concourse, as well as delis, bakeries, newsstands, a gourmet and fresh food market, an annex of the New York Transit Museum, and more than 40 retail stores. Among them are chain stores, including a Starbucks coffee shop, a Rite Aid pharmacy and, as of December 2011, an Apple Store.[9][10] Other chain restaurants include a Shake Shack.[11][12]

Grand Central Terminal's 49 acres (20 ha) basements are among the largest in the city.[13] This includes M42, a "secret" sub-basement under the terminal that contains the AC to DC converters used to supply DC traction current to the tracks. The exact location of M42 is a closely guarded secret and does not appear on maps, though it has been shown on the History Channel program Cities of the Underworld and a Nationa

Lake Superior ( World Largest freshwater Lake )

Lake Superior (French: Lac Supérieur) is the largest of the Great Lakes of North America. The lake is shared by the province of Ontario to the north in Canada, the states of Minnesota to the west, Wisconsin and Michigan to the south in the United States. It is generally considered the largest freshwater lake in the world by surface area. It is the world's third-largest freshwater lake by volume and the largest by volume in North America.[6]

Name Edit

The Ojibwe call the lake gichi-gami (pronounced as gitchi-gami and kitchi-gami in other dialects),[7] meaning "be a great sea." Henry Wadsworth Longfellow wrote the name as "Gitche Gumee" in The Song of Hiawatha, as did Gordon Lightfoot in his song, "The Wreck of the Edmund Fitzgerald". According to other sources the actual Ojibwe name is Ojibwe Gichigami ("Ojibwe's Great Sea") or Anishinaabe Gichigami ("Anishinaabe's Great Sea").[8] The 1878 dictionary by Father Frederic Baraga, the first one written for the Ojibway language, gives the Ojibwe name as Otchipwe-kitchi-gami (reflecting Ojibwe Gichigami).[7] The first French explorers approaching the great inland sea by way of the Ottawa River and Lake Huron during the 17th century referred to their discovery as le lac supérieur. Properly translated, the expression means "Upper Lake," that is, the lake above Lake Huron. The lake was also called Lac Tracy (named for Alexandre de Prouville de Tracy) by 17th century Jesuit missionaries.[9] The British, upon taking control of the region from the French in the 1760s following the French and Indian War, anglicized the lake's name to Superior, "on account of its being superior in magnitude to any of the lakes on that vast continent."[10]

Hydrography Edit

Lake Superior bathymetric map.[11][12][13] The deepest point, roughly off its southeastern shore, is marked with "×".[14] The deep trenches in its eastern part may have originated from tunnel valleys.[15][16]

Lake Superior empties into Lake Huron via the St. Marys River and the Soo Locks. Lake Superior is the largest freshwater lake in the world in area (if Lakes Michigan and Huron are taken separately; see Lake Michigan–Huron), and the third largest in volume, behind Lake Baikal in Siberia and Lake Tanganyika in East Africa. The Caspian Sea, while larger than Lake Superior in both surface area and volume, is brackish; though presently isolated, prehistorically the Caspian has been repeatedly connected to and isolated from the Mediterranean via the Black Sea.

Lake Superior deepest point[14] on the bathymetric map.[11]

Lake Superior has a surface area of 31,700 square miles (82,103 km2),[1] which is approximately the size of South Carolina or Austria. It has a maximum length of 350 statute miles (560 km; 300 nmi) and maximum breadth of 160 statute miles (257 km; 139 nmi).[2] Its average depth is 80.5 fathoms (483 ft; 147 m) with a maximum depth of 222.17 fathoms (1,333 ft; 406 m).[1][2][3] Lake Superior contains 2,900 cubic miles (12,100 km³) of water.[1] There is enough water in Lake Superior to cover the entire land mass of North and South America to a depth of 30 centimetres (12 in).[17] The shoreline of the lake stretches 2,726 miles (4,387 km) (including islands).[1]

American limnologist J. Val Klump was the first person to reach the lowest depth of Lake Superior on July 30, 1985, as part of a scientific expedition, which at 122 fathoms 1 foot (733 ft or 223 m) below sea level is the lowest spot in the continental interior of the United States and the second-lowest spot in the interior of the North American continent after the deeper Great Slave Lake in Canada (1,503 feet [458 m] below sea level). (Though Crater Lake is the deepest lake in the United States and deeper than Lake Superior, Crater Lake's elevation is higher and consequently its deepest point is 4,229 feet (1,289 m) above sea level.)

While the temperature of the surface of Lake Superior varies seasonally, the temperature below 110 fathoms (660 ft; 200 m) is an almo

Maglev train ( world's fastest )

Maglev (derived from magnetic levitation) is a transport method that uses magnetic levitation to move vehicles without touching the ground. With maglev, a vehicle travels along a guideway using magnets to create both lift and propulsion, thereby reducing friction by a great extent and allowing very high speeds.

The Shanghai Maglev Train, also known as the Transrapid, is the fastest commercial train currently in operation and has a top speed of 430 km/h (270 mph). The line was designed to connect Shanghai Pudong International Airport and the outskirts of central Pudong, Shanghai. It covers a distance of 30.5 kilometres (19.0 mi) in 8 minutes.[1] The Shanghai system was labeled a white elephant by rivals.[2]

Maglev trains move more smoothly and more quietly than wheeled mass transit systems. They are relatively unaffected by weather. The power needed for levitation is typically not a large percentage of its overall energy consumption;[3] most goes to overcome drag, as with other high-speed transport. Maglev trains hold the speed record for trains.

Compared to conventional trains, differences in construction affect the economics of maglev trains, making them much more efficient. For high-speed trains with wheels, wear and tear from friction along with dynamic augment from wheels on rails accelerates equipment wear and prevents high speeds.[4] Conversely, maglev systems have been much more expensive to construct, offsetting lower maintenance costs.

Despite decades of research and development, only two commercial maglev transport systems are in operation, with two others under construction.[note 1] In April 2004, Shanghai's Transrapid system began commercial operations. In March 2005, Japan began operation of its relatively low-speed HSST "Linimo" line in time for the 2005 World Expo. In its first three months, the Linimo line carried over 10 million passengers. South Korea became the world's second country to succeed in commercializing maglev technology with the Incheon Airport Maglev beginning commercial operation in February 3, 2016.[5]

Development

In the late 1940s, the British electrical engineer Eric Laithwaite, a professor at Imperial College London, developed the first full-size working model of the linear induction motor. He became professor of heavy electrical engineering at Imperial College in 1964, where he continued his successful development of the linear motor.[6] Since linear motors do not require physical contact between the vehicle and guideway, they became a common fixture on advanced transportation systems in the 1960s and 70s. Laithwaite joined one such project, the tracked hovercraft, although the project was cancelled in 1973.[7]

The linear motor was naturally suited to use with maglev systems as well. In the early 1970s, Laithwaite discovered a new arrangement of magnets, the magnetic river, that allowed a single linear motor to produce both lift and forward thrust, allowing a maglev system to be built with a single set of magnets. Working at the British Rail Research Division in Derby, along with teams at several civil engineering firms, the "transverse-flux" system was developed into a working system.

The first commercial maglev people mover was simply called "MAGLEV" and officially opened in 1984 near Birmingham, England. It operated on an elevated 600-metre (2,000 ft) section of monorail track between Birmingham Airport and Birmingham International railway station, running at speeds up to 42 km/h (26 mph). The system was closed in 1995 due to reliability problems.[8]

History

First maglev patent Edit

High-speed transportation patents were granted to various inventors throughout the world.[9] Early United States patents for a linear motor propelled train were awarded to German inventor Alfred Zehden. The inventor was awarded U.S. Patent 782,312 (14 February 1905) and U.S. Patent RE12,700 (21 August 1907).[note 2] In 1907, another early electromagnetic transportation system was developed

Tehri Dam ( India's Tallest )

The Tehri Dam is the tallest dam in India and one of the tallest in the world. It is a multi-purpose rock and earth-fill embankment dam on the Bhagirathi River near Tehri in Uttarakhand, India. It is the primary dam of the THDC India Ltd. and the Tehri hydroelectric complex. Phase 1 was completed in 2006, the Tehri Dam withholds a reservoir for irrigation, municipal water supply and the generation of 1,000 megawatts (1,300,000 hp) of hydroelectricity. The dam's 1,000  MW pumped-storage scheme is currently under construction with expected commissioning in May 2018.[1]

History

Tehri dam in November 2004

A preliminary investigation for the Tehri Dam Project was completed in 1961 and its design was completed in 1972 with a 600 MW capacity power plant based on the study. Construction began in 1978 after feasibility studies but was delayed due to financial, environmental and social impacts. In 1986, technical and financial assistance was provided by the USSR but this was interrupted years later with political instability. India was forced to take control of the project and at first it was placed under the direction of the Irrigation Department of Uttar Pradesh. However, in 1988 the Tehri Hydro Development Corporation was formed to manage the dam and 75% of the funding would be provide by the federal government, 25% by the state. Uttar Pradesh would finance the entire irrigation portion of the project. In 1990, the project was reconsidered and the design changed to its current multi-purpose.[2] Construction of the Tehri Dam was complete in 2006 while the second part of the project, the Koteshwar Dam was completed in 2012.

Technical description

The dam is a 260.5 metres (855 ft) high rock and earth-fill embankment dam. Its length is 575 metres (1,886 ft), crest width 20 metres (66 ft), and base width 1,128 metres (3,701 ft). The dam creates a reservoir of 4.0 cubic kilometres (3,200,000 acre·ft) with a surface area of 52 square kilometres (20 sq mi). The installed hydrocapacity is 1,000 MW along with an additional 1,000 MW of pumped storage hydroelectricity. The lower reservoir for the pumped-storage plant is created by the Koteshwar Dam downstream.

The Tehri Dam and the Tehri Pumped Storage Hydroelectric Power Plant are part of the Tehri Hydropower Complex which also includes the 400 MW Koteshwar Dam.[2] Power is distributed to Uttar Pradesh, Uttarakhand, Punjab, Delhi, Haryana, Jammu & Kashmir, Chandigarh, Rajasthan and Himachal Pradesh. The complex will afford irrigation to an area of 270,000 hectares (670,000 acres), irrigation stabilization to an area of 600,000 hectares (1,500,000 acres), and a supply of 270 million imperial gallons (1.2×106 m3) of drinking water per day to the industrialized areas of Delhi, Uttar Pradesh and Uttarakhand. The total expenditure for this project was 1 billion U.S. dollars. The Indian National Trust for Art and Cultural Heritage (INTACH),a cost benefit analysis was commissioned and was concluded that the construction cost of the dam twice the projected benefits.[3]

Scheduling and generation despatch Edit

The Scheduling and Despatch of the Tehri Hydro Power plant is done by Northern Regional Load Despatch Centre which is the apex body to ensure the integrated operation of the power system grid in the Northern region and comes under Power System Operation Corporation Limited (POSOCO). At present, THDC India Ltd. is generating around 3000 million Unit of energy annually from this dam.

The main Power house of Tehri Dam that houses 4 generators each capable of producing 250 MW of power.

Environmental issues Edit

Tehri dam in July 2008

The Tehri Dam has been the object of protests by environmental organizations and local people of the region. In addition to the human rights concerns, the project has spurred concerns about the environmental consequences of locating such a large dam in the fragile ecosystem of the Himalayan foothills. There are further concerns regarding the dam's geol

Hirakud Dam ( Asia's longest )

The Hirakud Dam is a composite structure of earth, concrete and masonry. 10 km (6 mi) north of Sambalpur, it is the longest major earthen dam in Asia, measuring 25.8 km (16 mi) including dykes, and stands across the river Mahanadi.

Pir Panjal Railway Tunnel ( India's longest)

The Pir Panjal Railway Tunnel or Banihal railway tunnel is an 11.215 km (7 mile) railway tunnel located in Pir Panjal Range of middle Himalayas in Jammu and Kashmir, India, north of Banihal town.