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 electrical power when combined with a generator. A turbine is a turbomachine with at least one moving part called a rotor assembly, a shaft or drum with blades attached. Moving fluid acts on the blades so that they impart rotational energy to the rotor. Early turbine examples are waterwheels. Gas and water turbines have a casing around the blades that contains and controls the working fluid. Credit for invention of the steam turbine is given both to Anglo-Irish engineer Sir Charles Parsons for invention of the reaction turbine, to Swedish engineer Gustaf de Laval for invention of the impulse turbine. Modern steam turbines employ both reaction and impulse in the same unit varying the degree of reaction and impulse from the blade root to its periphery; the word "turbine" was coined in 1822 by the French mining engineer Claude Burdin from the Latin turbo, or vortex, in a memo, "Des turbines hydrauliques ou machines rotatoires à grande vitesse", which he submitted to the Académie royale des sciences in Paris.
Benoit Fourneyron, a former student of Claude Burdin, built the first practical water turbine. A working fluid contains kinetic energy; the fluid may be incompressible. Several physical principles are employed by turbines to collect this energy: Impulse turbines change the direction of flow of a high velocity fluid or gas jet; the resulting impulse leaves the fluid flow with diminished kinetic energy. There is no pressure change of the fluid or gas in the turbine blades, as in the case of a steam or gas turbine, all the pressure drop takes place in the stationary blades. Before reaching the turbine, the fluid's 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. Newton's 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 fluid's pressure or mass. The pressure of the gas or fluid changes. A pressure casement is needed to contain the working fluid as it acts on the turbine stage or the turbine must be immersed in the fluid flow; the casing contains and directs the working fluid and, for water turbines, maintains the suction imparted by the draft tube. Francis turbines and most steam turbines use this concept. For compressible working fluids, multiple turbine stages are used to harness the expanding gas efficiently. Newton's 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 the case of steam turbines, such as would be used for marine applications or for land-based electricity generation, a Parsons-type reaction turbine would require double the number of blade rows as a de Laval-type impulse turbine, for the same degree of thermal energy conversion.
Whilst this makes the Parsons turbine much longer and heavier, the overall efficiency of a reaction turbine is higher than the equivalent impulse turbine for the same thermal energy conversion. In practice, modern turbine designs use both reaction and impulse concepts to varying degrees whenever possible. Wind turbines use an airfoil to generate a reaction lift from the moving fluid and impart it to the rotor. Wind turbines gain some energy from the impulse of the wind, by deflecting it at an angle. Turbines with multiple stages may use either impulse blading at high pressure. Steam turbines were traditionally more impulse but continue to move towards reaction designs similar to those used in gas turbines. At low pressure the operating fluid medium expands in volume for small reductions in pressure. Under these conditions, blading becomes a reaction type design with the base of the blade impulse; the reason is due to the effect of the rotation speed for each blade. As the volume increases, the blade height increases, the base of the blade spins at a slower speed relative to the tip.
This change in speed forces a designer to change from impulse at the base, to a high reaction-style tip. Classical turbine design methods were developed in the mid 19th century. Vector analysis related the fluid flow with turbine rotation. Graphical calculation methods were used at first. Formulae for the basic dimensions of turbine parts are well documented and a efficient machine can be reliably designed for any fluid flow condition; some of the calculations are empirical or'rule of thumb' formulae, others are based on classical mechanics. As with most engineering calculations, simplifying assumptions were made. Velocity triangles can be used to calculate the basic performance of a turbine stage. Gas exits the stationary turbine nozzle guide vanes at absolute velocity Va1; the rotor rotates at velocity U. Relative to the rotor, the velocity of the gas as it impinges on the rotor entrance is Vr1; the gas is turned by the rotor and exits, relative to the rotor, at velocity Vr2. However, in absolute terms the rotor exit velocity is Va2.
The velocity t
The United Nations Educational and Cultural Organization is a specialized agency of the United Nations based in Paris. Its declared purpose is to contribute to peace and security by promoting international collaboration through educational and cultural reforms in order to increase universal respect for justice, the rule of law, human rights along with fundamental freedom proclaimed in the United Nations Charter, it is the successor of the League of Nations' International Committee on Intellectual Cooperation. UNESCO has 11 associate members. Most of its field offices are "cluster" offices covering three or more countries. UNESCO pursues its objectives through five major programs: education, natural sciences, social/human sciences and communication/information. Projects sponsored by UNESCO include literacy and teacher-training programs, international science programs, the promotion of independent media and freedom of the press and cultural history projects, the promotion of cultural diversity, translations of world literature, international cooperation agreements to secure the world's cultural and natural heritage and to preserve human rights, attempts to bridge the worldwide digital divide.
It is a member of the United Nations Development Group. UNESCO's aim is "to contribute to the building of peace, the eradication of poverty, sustainable development and intercultural dialogue through education, the sciences, culture and information". Other priorities of the organization include attaining quality Education For All and lifelong learning, addressing emerging social and ethical challenges, fostering cultural diversity, a culture of peace and building inclusive knowledge societies through information and communication; the broad goals and objectives of the international community—as set out in the internationally agreed development goals, including the Millennium Development Goals —underpin all UNESCO strategies and activities. UNESCO and its mandate for international cooperation can be traced back to a League of Nations resolution on 21 September 1921, to elect a Commission to study feasibility; this new body, the International Committee on Intellectual Cooperation was indeed created in 1922.
On 18 December 1925, the International Bureau of Education began work as a non-governmental organization in the service of international educational development. However, the onset of World War II interrupted the work of these predecessor organizations. After the signing of the Atlantic Charter and the Declaration of the United Nations, the Conference of Allied Ministers of Education began meetings in London which continued from 16 November 1942 to 5 December 1945. On 30 October 1943, the necessity for an international organization was expressed in the Moscow Declaration, agreed upon by China, the United Kingdom, the United States and the USSR; this was followed by the Dumbarton Oaks Conference proposals of 9 October 1944. Upon the proposal of CAME and in accordance with the recommendations of the United Nations Conference on International Organization, held in San Francisco in April–June 1945, a United Nations Conference for the establishment of an educational and cultural organization was convened in London 1–16 November 1945 with 44 governments represented.
The idea of UNESCO was developed by Rab Butler, the Minister of Education for the United Kingdom, who had a great deal of influence in its development. At the ECO/CONF, the Constitution of UNESCO was introduced and signed by 37 countries, a Preparatory Commission was established; the Preparatory Commission operated between 16 November 1945, 4 November 1946—the date when UNESCO's Constitution came into force with the deposit of the twentieth ratification by a member state. The first General Conference took place from 19 November to 10 December 1946, elected Dr. Julian Huxley to Director-General; the Constitution was amended in November 1954 when the General Conference resolved that members of the Executive Board would be representatives of the governments of the States of which they are nationals and would not, as before, act in their personal capacity. This change in governance distinguished UNESCO from its predecessor, the ICIC, in how member states would work together in the organization's fields of competence.
As member states worked together over time to realize UNESCO's mandate and historical factors have shaped the organization's operations in particular during the Cold War, the decolonization process, the dissolution of the USSR. Among the major achievements of the organization is its work against racism, for example through influential statements on race starting with a declaration of anthropologists and other scientists in 1950 and concluding with the 1978 Declaration on Race and Racial Prejudice. In 1956, the Republic of South Africa withdrew from UNESCO saying that some of the organization's publications amounted to "interference" in the country's "racial problems." South Africa rejoined the organization in 1994 under the leadership of Nelson Mandela. UNESCO's early work in the field of education included the pilot project on fundamental education in the Marbial Valley, started in 1947; this project was followed by expert missions to other countries, for example, a mission to Afghanistan in 1949.
In 1948, UNESCO recommended that Member States should make free primary education compulsory and universal. In 1990, the World Conference on Education for All, in Jomtien, launched a global movement to provide basic education for a
Government of Queensland
The Government of Queensland referred to as the Queensland Government, is the Australian state democratic administrative authority of Queensland. The Government of Queensland, a parliamentary constitutional monarchy, was formed in 1859 as prescribed in its Constitution, as amended from time to time. Since the Federation of Australia in 1901, Queensland has been a state of the Commonwealth of Australia, the Constitution of Australia regulates its relationship with the Commonwealth. Under the Australian Constitution, Queensland ceded legislative and judicial supremacy to the Commonwealth, but retained powers in all matters not in conflict with the Commonwealth. Key state government offices are located at 1 William Street in the Brisbane central business district; the Government of Queensland operates under the Westminster system, a form of parliamentary government based on the model of the United Kingdom. The Governor of Queensland, as the representative of Elizabeth II, Queen of Australia, holds nominal power, although in practice only performs ceremonial duties.
The Parliament of Queensland holds legislative power, while executive power lies with the Premier and Cabinet, judicial power is exercised by a system of courts and tribunals. The Parliament of Queensland is the state's legislature, it consists of Her Majesty The Queen, a single chamber. Queensland is the only Australian state with a unicameral parliament after a second chamber, the Legislative Council, was abolished in 1922; the Legislative Assembly has 93 members. Elections for the Legislative Assembly are held every four years; the Cabinet of Queensland is the government's chief policy-making organ, consists of the Premier and all ministers. The Queensland Government delivers services, determines policy and regulations, including legal interpretation, by a number of agencies grouped under areas of portfolio responsibility; each portfolio is led by a government minister, a member of the Parliament. As of April 2016 there were nineteen lead agencies, called government departments, that consist of: Department of the Premier and Cabinet Department of Aboriginal and Torres Strait Islander Partnerships Department of Agriculture and Fisheries Department of Communities, Child Safety and Disability Services Department of Education and Training Department of Energy and Water Supply Department of Environment and Heritage Protection Queensland Health Department of Housing and Public Works Department of Infrastructure, Local Government and Planning Department of Justice and Attorney-General Department of National Parks and Racing Department of Natural Resources and Mines Queensland Police Service and Queensland Fire and Emergency Services Department of Science, Information Technology and Innovation Department of State Development Department of Transport and Main Roads Queensland Treasury Department of Tourism, Major Events, Small Business and the Commonwealth GamesA range of other agencies support the functions of these departments.
The judiciary of Queensland consists of the Magistrates Court, the District Court, the Supreme Court, as well as a number of smaller courts and tribunals. The Chief Justice of Queensland is the state's most senior judicial officer; the Magistrates Court is the lowest tier of the judicial hierarchy of Queensland. The court's criminal jurisdiction covers summary offences, indictable offences which may be heard summarily, but all criminal proceedings in Queensland begin in the Magistrates Court if they are not within this jurisdiction. For charges beyond its jurisdiction, the court conducts committal hearings in which the presiding magistrate decides, based on the strength of the evidence, whether to refer the matter to a higher court or dismiss it; the court's civil jurisdiction covers matters in which the amount in dispute is less than or equal to $150,000. Appeals against decisions by the Magistrates Court are heard by the District Court; the District Court is the middle tier of the judicial hierarchy of Queensland.
The court has jurisdiction to hear all appeals from decisions made in the Magistrates Court. Its criminal jurisdiction covers serious indictable offences; the court's civil jurisdiction covers matters in which the amount in dispute is more than $150,000 but less than or equal to $750,000. Appeals against decisions by the District Court are heard by the Court of Appeal, a division of the Supreme Court; the Supreme Court is the highest tier of the judicial hierarchy Queensland. The court has two divisions; the Trial Division's jurisdiction covers serious criminal offences, civil matters involving claims of more than $750,000. The Court of Appeal's jurisdiction allows it to hear cases on appeal from the Trial Division, the District Court, a number of other judicial tribunals in Queensland. Appeals against decisions by the Court of Appeal are heard by the High Court of Australia. There are several factors; the legislature has no upper house. For a large portion of its history, the state was under a gerrymander that favoured rural electorates.
This, combined with the decentralised nature of Queensland, meant that politics has been dominated by regional interests. Queensland, along with New South Wales operated a balloting system known as Optional Preferential Voting for state elections; this is different from the predominant Australian electoral system, the instant-runoff voting system, in practice is closer to a first past the post ballot, which some say is to the
A power station referred to as a power plant or powerhouse and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Most power stations contain one or more generators, a rotating machine that converts mechanical power into electrical power; the relative motion between a magnetic field and a conductor creates an electrical current. The energy source harnessed to turn the generator varies widely. Most power stations in the world burn fossil fuels such as coal and natural gas to generate electricity. Others use nuclear power, but there is an increasing use of cleaner renewable sources such as solar, wind and hydroelectric. In 1878 a hydroelectric power station was built by Lord Armstrong at Cragside, England, it used water from lakes on his estate to power Siemens dynamos. The electricity supplied power to lights, produced hot water, ran an elevator as well as labor-saving devices and farm buildings. In the early 1870s Belgian inventor Zénobe Gramme invented a generator powerful enough to produce power on a commercial scale for industry.
In the autumn of 1882, a central station providing public power was built in England. It was proposed after the town failed to reach an agreement on the rate charged by the gas company, so the town council decided to use electricity, it used hydroelectric power for household lighting. The system was not the town reverted to gas. In 1882 the world's first coal-fired public power station, the Edison Electric Light Station, was built in London, a project of Thomas Edison organized by Edward Johnson. A Babcock & Wilcox boiler powered a 125-horsepower steam engine; this supplied electricity to premises in the area that could be reached through the culverts of the viaduct without digging up the road, the monopoly of the gas companies. The customers included the Old Bailey. Another important customer was the Telegraph Office of the General Post Office, but this could not be reached though the culverts. Johnson arranged for the supply cable to be run overhead, via Holborn Newgate. In September 1882 in New York, the Pearl Street Station was established by Edison to provide electric lighting in the lower Manhattan Island area.
The station ran until destroyed by fire in 1890. The station used reciprocating steam engines to turn direct-current generators; because of the DC distribution, the service area was small. In 1886 George Westinghouse began building an alternating current system that used a transformer to step up voltage for long-distance transmission and stepped it back down for indoor lighting, a more efficient and less expensive system, similar to modern system; the War of Currents resolved in favor of AC distribution and utilization, although some DC systems persisted to the end of the 20th century. DC systems with a service radius of a mile or so were smaller, less efficient of fuel consumption, more labor-intensive to operate than much larger central AC generating stations. AC systems used a wide range of frequencies depending on the type of load; the economics of central station generation improved when unified light and power systems, operating at a common frequency, were developed. The same generating plant that fed large industrial loads during the day, could feed commuter railway systems during rush hour and serve lighting load in the evening, thus improving the system load factor and reducing the cost of electrical energy overall.
Many exceptions existed, generating stations were dedicated to power or light by the choice of frequency, rotating frequency changers and rotating converters were common to feed electric railway systems from the general lighting and power network. Throughout the first few decades of the 20th century central stations became larger, using higher steam pressures to provide greater efficiency, relying on interconnections of multiple generating stations to improve reliability and cost. High-voltage AC transmission allowed hydroelectric power to be conveniently moved from distant waterfalls to city markets; the advent of the steam turbine in central station service, around 1906, allowed great expansion of generating capacity. Generators were no longer limited by the power transmission of belts or the slow speed of reciprocating engines, could grow to enormous sizes. For example, Sebastian Ziani de Ferranti planned what would have been the largest reciprocating steam engine built for a proposed new central station, but scrapped the plans when turbines became available in the necessary size.
Building power systems out of central stations required combinations of engineering skill and financial acumen in equal measure. Pioneers of central station generation include George Westinghouse and Samuel Insull in the United States and Charles Hesterman Merz in UK, many others. In thermal power stations, mechanical power is produced by a heat engine that transforms thermal energy from combustion of a fuel, into rotational energy. Most thermal power stations produce steam, so they are sometimes called steam power stations. Not all thermal energy can be transformed into mechanical power, according to the second law of thermodynamics. If this loss is employed as useful heat, for industrial processes or district heating, the power plant is referred to as a cogeneration power plant or CHP plant. In countries where district heating is common, there are dedicated he
Underground power station
An underground power station is a type of hydroelectric power station constructed by excavating the major components from rock, rather than the more common surface-based construction methods. One or more conditions impact; the terrain or geology around a dam is taken into consideration, as gorges or steep valleys may not accommodate a surface power station. A power station within bedrock may be less expensive to construct than a surface power station on loose soil. Avalanche-prone valleys make a surface station unfeasible as well. After World War II, large hydroelectric power stations were placed underground more in order to protect them from airstrikes. Underground power stations form part of pumped storage hydroelectricity schemes, whose basic function is to level load: they use cheap or surplus off-peak power to pump water from a lower lake to an upper lake. During peak periods, the power station generates power from the water held in the upper lake; some notable underground power stations are: Boundary Dam Powerhouse, in Pend Oreille County, United States, completed in 1967 and diverting the Pend Oreille River through six units, Boundary Powerhouse produces 1070 MW.
Owned and operated by Seattle City Light. Chaira Hydro Power Plant, Bulgaria, is the largest underground power station in the Balkans, built from 1980 to 1998, it has an installed capacity of 864 MW from four 216 MW reversible Francis turbines with a net rated head of 2,300 feet, maximal speed of 600 rpm. Churchill Falls Generating Station and Labrador, Canada is the second largest underground power station in the world, it generates 5,428 MW from 11 turbines. The powerhouse is 148 feet high, 62 feet wide and located 1,080 feet underground; the two tailrace tunnels are 1691.64 m long. The net head is 312.42 m. Cruachan Dam, United Kingdom, built in the early 1960s, a pumped storage plant generating 440 MW from 4 turbines. Dinorwig Power Station, United Kingdom, built in 1984, is a pumped-storage system, delivering 1,650 MW to Wales and the north-west of England, it stands in Europe's largest man-made cavern. Edward Hyatt Power Plant inside the Oroville Dam, United States, is in a cavern carved into the bedrock of the Feather River canyon.
It houses 3 Generator and 3 Pump/Generator units and their respective Transformers 650 feet below the crest of the dam. Goldisthal Pumped Storage Station, in Thuringia, built in 1991-2004, generates 1,060 MW from 4 turbines, it is unique in Europe, in that two of the four motor generators are designed as variable speed asynchronous machines. The machine hall is 161 feet high, 52 feet wide, with a separate transformer cavern. Kannagawa Hydropower Plant is under construction in Japan; when completed, it will be the world's largest pumped storage plant, generating 2,700 MW. The power house is 108 feet wide, 171 feet high; the effective head is 2,343 feet The first unit commenced operations in 2005, the second in 2012. Kariba hydro-electric power scheme is on the Zambezi river, which forms the border between Zimbabwe and Zambia; the Kariba system comprises two underground power stations. The Kariba South station in Zimbabwe houses six 100 MW generators; the Kariba North station in Zambia houses four 150 MW generators.
Kazunogawa Power Station is a 1,200 MW underground pumped storage plant in Japan. Kazunogawa consists of four 400 MW generation units; the cavern for the underground power station is 1,600 feet below the surface. It is 690 feet long by 112 feet wide; the head is 2,343 feet. Manapouri Power Station, New Zealand, built 1963-1972, generates 850 MW from 7 turbines, it is built 660 feet underground, has two 10 km tailrace tunnels. The net head is 560 feet; the most notable feature of this station is that the lake and power station are located on the eastern side of the Southern Alps, with the tailrace tunnels traveling under a major mountain range, discharging in Doubtful Sound on the west coast. Paulo Afonso Hydroelectric Complex, Brazil. Completed in 1955, PA I was Brazil's first underground power station. Poatina Hydroelectric Power Station, Australia, built in 1966-1977 it generates 300 MW with water provided by the Great Lake, it is the largest underground power station in Australia. Raccoon Mountain Pumped-Storage Plant, Tennessee, United States, built in 1970-1978 generates 1,530 MW.
It is an early test of the pumped-storage approach. Robert-Bourassa generating station, Canada is the largest underground power station in the world, it generates 5,616 MW from 16 turbines with a net rated head of 450 feet. Snoqualmie Falls Hydroelectric Plant in King County, United States, built in two stages, Plant 1, completed in 1899 was the world's first underground power station and is still used to provide power to the Seattle area; the two power houses have a combined installed capacity of 53.9 MW. Underground power stations
A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using the weight of the material alone to resist the horizontal pressure of water pushing against it. Gravity dams are designed so that each section of the dam is stable, independent of any other dam section. Gravity dams require stiff rock foundations of high bearing strength; the bearing strength of the foundation limits the allowable position of the resultant which influences the overall stability. The stiff nature of the gravity dam structure is unforgiving to differential foundation settlement. Gravity dams provide some advantages over embankment dams; the main advantage being that they can tolerate minor over-topping flows as the concrete is resistant to scouring. Large over-topping flows are still a problem, as they can scour the foundations if not accounted for in the design. A disadvantage of gravity dams is that due to their large footprint, they are susceptible to uplift pressures which act as a de-stabilising force.
Uplift pressures can be reduced by internal and foundation drainage systems which reduces the pressures. During construction, the setting concrete produces a exothermic reaction; this heat can take up to several decades to cool. When cooling, the concrete is susceptible to cracking, it is the designer's task to ensure. The most common classification of gravity dams is by the materials composing the structure: Concrete dams include mass concrete dams, made of: conventional concrete: Dworshak Dam, Grand Coulee Dam Roller-Compacted Concrete: Willow Creek Dam, Upper Stillwater Dam masonry: Pathfinder Dam, Cheesman Dam hollow gravity dams, made of reinforced concrete: Braddock DamComposite dams are a combination of concrete and embankment dams. Construction materials of composite dams are the same used for embankment dams. Gravity dams can be classified by plan: Most gravity dams are straight; some masonry and concrete gravity dams have the dam axis curved to add stability through arch action. Gravity dams can be classified with respect to their structural height: Low, up to 100 feet.
Medium high, between 100 and 300 feet. High, over 300 feet. Kollgaardand, E. B.. L.. Development of Dam Engineering in the United States. US Committee of the International Commission on Large Dams. Dams of the United States - Pictorial display of Landmark Dams. Denver, Colorado: US Society on Dams. 2013