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Pelton-type
The Pelton wheel or Pelton Turbine is an impulse-type water turbine invented by American inventor Lester Allan Pelton in the 1870s. The Pelton wheel extracts energy from the impulse of moving water, as opposed to water's dead weight like the traditional overshot water wheel. Many earlier variations of impulse turbines existed, but they were less efficient than Pelton's design. Water leaving those wheels typically still had high speed, carrying away much of the dynamic energy brought to the wheels. Pelton's paddle geometry was designed so that when the rim ran at half the speed of the water jet, the water left the wheel with very little speed; thus his design extracted almost all of the water's impulse energywhich made for a very efficient turbine. History file:Pelton wheel (patent).png, Figure from Lester Allan Pelton's original October 1880 patent Lester Allan Pelton was born in Vermillion, Ohio in 1829. In 1850, he traveled overland to take part in the California Gold Rush. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nevada City, California
Nevada City (originally, ''Ustumah'', a Nisenan village; later, Nevada, Deer Creek Dry Diggins, and Caldwell's Upper Store) is the county seat of Nevada County, California, United States, northeast of Sacramento, southwest of Reno and northeast of San Francisco. The population was 3,068 as of the 2010 Census. History European-Americans first settled Nevada City in 1849, during the California Gold Rush, as Nevada (Spanish for "snow-covered", a reference to the snow-topped mountains in the area). The ''Gold Tunnel'' on the north side of Deer Creek was the city's first mine, built in 1850. The first sawmill in Nevada City was built on Deer Creek, just above town, in August 1850, by Lewis & Son, with a water wheel. In 1850–51, Nevada City was the state's most important mining town, and Nevada County the state's leading gold-mining county. In 1851, '' The Nevada Journal'' became the first newspaper published in the town and county. The first cemetery in town, the Pioneer Cemeter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroelectricity
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other Renewable energy, renewable sources combined and also more than nuclear power. Hydropower can provide large amounts of Low-carbon power, low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel-powered energy plants. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing (mechanical)
A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may ''prevent'' a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts. Rotary bearings hold rotating components such as shafts or axles within mechanical systems, and transfer axial and radial loads from the source of the load to the structure supporting it. The simplest form of bearing, the ''plain bearing'', consists of a shaft rotating in a hole. Lubrication is used to reduce friction. In the ''ball bearing'' and ''roller bearing'', to reduce sliding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Head
Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22. It is usually measured as a liquid surface elevation, expressed in units of length, at the entrance (or bottom) of a piezometer. In an aquifer, it can be calculated from the depth to water in a piezometric well (a specialized water well), and given information of the piezometer's elevation and screen depth. Hydraulic head can similarly be measured in a column of water using a standpipe piezometer by measuring the height of the water surface in the tube relative to a common datum. The hydraulic head can be used to determine a ''hydraulic gradient'' between two or more points. "Head" in fluid dynamics In fluid dynamics, ''head'' is a concept that relates the energy in an incompressible fluid to the height of an equivalent static column of that fluid. From Bernoulli's principle, the total energy at a given point in a fluid i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body when decelerating from its current speed to a state of rest. Formally, a kinetic energy is any term in a system's Lagrangian which includes a derivative with respect to time. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2. In relativistic mechanics, this is a good approximation only when ''v'' is much less than the speed of light. The standard unit of kinetic energy is the joule, while the English unit of kinetic energy is the foot-pound. History and etymology The adjective ''kinetic'' has its roots in the Greek word κίνησις ''kinesis'', m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Work (physics)
In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force strength and the distance traveled. A force is said to do ''positive work'' if when applied it has a component in the direction of the displacement of the point of application. A force does ''negative work'' if it has a component opposite to the direction of the displacement at the point of application of the force. For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is positive, and is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). If the ball is thrown upwards, the work done by its weight is negative, and is equal to the weight multiplied by the displacement in the upwards direction. When the force is consta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impulse (physics)
In classical mechanics, impulse (symbolized by or Imp) is the integral of a force, , over the time interval, , for which it acts. Since force is a vector quantity, impulse is also a vector quantity. Impulse applied to an object produces an equivalent vector change in its linear momentum, also in the resultant direction. The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram meter per second (kg⋅m/s). The corresponding English engineering unit is the pound-second (lbf⋅s), and in the British Gravitational System, the unit is the slug-foot per second (slug⋅ft/s). A resultant force causes acceleration and a change in the velocity of the body for as long as it acts. A resultant force applied over a longer time, therefore, produces a bigger change in linear momentum than the same force applied briefly: the change in momentum is equal to the product of the average force and duration. Conversely, a small force ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thames, New Zealand
Thames () ( mi, Pārāwai) is a town at the southwestern end of the Coromandel Peninsula in New Zealand's North Island. It is located on the Firth of Thames close to the mouth of the Waihou River. The town is the seat of the Thames-Coromandel (district), New Zealand, Thames-Coromandel District Council. The Māori people, Māori iwi are Ngāti Maru (Hauraki), Ngāti Maru, who are descendants of Marutuahu's son Te Ngako. Ngāti Maru is part of the Ngati Marutuahu confederation of tribes or better known as Hauraki Iwi. Thames had an estimated population of 15,000 in 1870, but this declined to 4,500 in 1881, and it has increased modestly since. It is still the biggest town on the Coromandel. Until 2016, a historical Oak, oak tree that was planted by Governor George Grey stood on the corner of Grey and Rolleston streets. Demographics Thames covers and had an estimated population of as of with a population density of people per km2. Thames had a population of 7,293 at the 2018 Ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A & G Price
A & G Price Limited is an engineering firm and locomotive manufacturer in Thames, New Zealand founded in 1868. History A & G Price was established in 1868 in Princes Street, Onehunga by Alfred Price and George Price, two brothers from Stroud, Gloucestershire. They built almost 100 flax-milling machines in their first year.Book Reviews ''Rails'' June 1983 page 22 The brothers also built machinery for gold miners. They moved to the Coromandel Gold Rushes in 1871 setting up premises in Beach Road, Thames and closing the Onehunga works in 1873 after building 10 coaches and 12 trucks there for the Public Works Department. The firm's ownership was transferred to a limited liability company in 1907. Ownership A & G Price Limited remained under family management until November 1949 when it was bought by Wellington engineers, William Cable & Company. The two companies then exchanged board members but kept their separate identities. Cable bought Downer & Co in 1954 and in 1964 Willia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
