A valve is a device or natural object that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure. The word is derived from the Latin valva, the moving part of a door, in turn from volvere, to turn, roll.
Water polo is a competitive team sport played in water between two teams of seven players each. The game consists of four quarters in which the teams attempt to score goals by throwing the ball into the opposing team's goal. The team with the most goals at the end of the game wins the match. Each team is made up of six field players and one goalkeeper. Excluding the goalkeeper, players participate in both offensive and defensive roles. It is typically played in an all-deep pool where players cannot touch the bottom.
A lock is a device used for raising and lowering boats, ships and other watercraft between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is the chamber itself that rises and falls.
A sluice is a channel controlled at its head by a movable gate which is called a sluice gate. A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway and can be considered as a bottom opening in a wall. Sluice gates are one of the most common hydraulic structures in controlling flow rate and water level in open channels such as rivers and canals. They also could be used to measure the flow. A water channel containing a sluice gate forms a type of lock to manage the water flow and water level. It can also be an open channel which processes material, such as a River Sluice used in gold prospecting or fossicking. A mill race, leet, flume, penstock or lade is a sluice channeling water toward a water mill. The terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry. They are also used in wastewater treatment plants and to recover minerals in mining operations, and in watermills.
A Stargate is an Einstein–Rosen bridge portal device within the Stargate fictional universe that allows practical, rapid travel between two distant locations. The devices first appeared in the 1994 Roland Emmerich film Stargate, and thereafter in the television series Stargate SG-1, Stargate Atlantis, and Stargate Universe. In these productions, the Stargate functions as a plot device, allowing the main characters to visit alien planets without the need for spaceships or any other type of technology. The device allows for near-instantaneous travel across both interstellar and extragalactic distances.
A noise gate or gate is an electronic device or software that is used to control the volume of an audio signal. Comparable to a compressor, which attenuates signals above a threshold, such as loud attacks from the start of musical notes, noise gates attenuate signals that register below the threshold. However, noise gates attenuate signals by a fixed amount, known as the range. In its simplest form, a noise gate allows a main signal to pass through only when it is above a set threshold: the gate is "open". If the signal falls below the threshold, no signal is allowed to pass : the gate is "closed". A noise gate is used when the level of the "signal" is above the level of the unwanted "noise". The threshold is set above the level of the "noise", and so when there is no main "signal", the gate is closed.
A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure that water does not damage parts of the structure not designed to convey water.
In competitive rowing, the following specialized terms are important in the corresponding aspects of the sport:
Floodgates, also called stop gates, are adjustable gates used to control water flow in flood barriers, reservoir, river, stream, or levee systems. They may be designed to set spillway crest heights in dams, to adjust flow rates in sluices and canals, or they may be designed to stop water flow entirely as part of a levee or storm surge system. Since most of these devices operate by controlling the water surface elevation being stored or routed, they are also known as crest gates. In the case of flood bypass systems, floodgates sometimes are also used to lower the water levels in a main river or canal channels by allowing more water to flow into a flood bypass or detention basin when the main river or canal is approaching a flood stage.
In photography and optics, a neutral-density filter, or ND filter, is a filter that reduces or modifies the intensity of all wavelengths, or colors, of light equally, giving no changes in hue of color rendition. It can be a colorless (clear) or grey filter, and is denoted by Wratten number 96. The purpose of a standard photographic neutral-density filter is to reduce the amount of light entering the lens. Doing so allows the photographer to select combinations of aperture, exposure time and sensor sensitivity that would otherwise produce overexposed pictures. This is done to achieve effects such as a shallower depth of field or motion blur of a subject in a wider range of situations and atmospheric conditions.
The Tainter gate is a type of radial arm floodgate used in dams and canal locks to control water flow. It is named for Wisconsin structural engineer Jeremiah Burnham Tainter.
The Panama Canal locks are a lock system that lifts ships up 85 feet to the main elevation of the Panama Canal and down again. The original canal had a total of six steps for a ship's passage. The total length of the lock structures, including the approach walls, is over 1.9 miles (3 km). The locks were one of the greatest engineering works ever to be undertaken when they opened in 1914. No other concrete construction of comparable size was undertaken until the Hoover Dam, in the 1930s.
MOSE is a project intended to protect the city of Venice, Italy, and the Venetian Lagoon from flooding.
The Morganza Spillway or Morganza Control Structure is a flood-control structure in the U.S. state of Louisiana. It is located along the western bank of the Lower Mississippi River at river mile 280, near Morganza in Pointe Coupee Parish. The spillway stands between the Mississippi and the Morganza Floodway, which leads to the Atchafalaya Basin and the Atchafalaya River in south-central Louisiana. Its purpose is to divert water from the Mississippi River during major flood events by flooding the Atchafalaya Basin, including the Atchafalaya River and the Atchafalaya Swamp. The spillway and adjacent levees also help prevent the Mississippi from changing its present course through the major port cities of Baton Rouge and New Orleans to a new course down the Atchafalaya River to the Gulf of Mexico. The Morganza Spillway, operated by the U.S. Army Corps of Engineers, was opened during the 1973 and 2011 Mississippi River floods.
The First Siege of Rome during the Gothic War lasted for a year and nine days, from 2 March 537 to 12 March 538. The city was besieged by the Ostrogothic army under their king Vitiges; the defending East Romans were commanded by Belisarius, one of the most famous and successful Roman generals. The siege was the first major encounter between the forces of the two opponents, and played a decisive role in the subsequent development of the war.
The Schooner Bayou Control Structure is a flood control structure located in Vermilion Parish, Louisiana, and operated by the U.S. Army Corps of Engineers. It is part of the Mississippi Valley Division, New Orleans District, which encompasses the southern half of the state of Louisiana.
An incident pit is a conceptual pit with sides that become steeper over time and with each new incident until a point of no return is reached. As time moves forward, seemingly innocuous incidents push a situation further toward a bad situation and escape from the incident pit becomes more difficult. An incident pit may or may not have a point of no return such as an event horizon.
The Vasse and Wonnerup Floodgates is a heritage listed site in Western Australia that comprises two locations. The two locations are the site of the Vasse floodgates on the Vasse River and the Wonnerup floodgates on the Wonnerup Estuary. In addition, the 2004 site of the Vasse floodgates was also the site of the Ballarat Bridge which was built in 1871 as part of a logging rail line where the Ballarat Steam engine was the first steam engine to operate in Western Australia.
The Cheruthoni Dam, located in Idukki District, Kerala, India, is a 138m tall concrete gravity dam. Preliminary work on this project was initiated under the leadership of Superintending Engineer, E.U.Philipose.This dam was constructed in 1976 as part of the Idukki Hydroelectric Project along with two other dams Idukki and Kulamavu. The Government of Canada aided the Project with long-term loans and grants. The dam was constructed by HCC and the consultant was S.N.C.Inc., Canada,
The floodgates principle, or the floodgates argument, is a legal principle which is sometimes applied by judges to restrict or limit the right to make claims for damages because of a concern that permitting a claimant to recover in such situations might open the metaphorical "floodgates" to large numbers of claims and lawsuits. The principle is most frequently cited in common law jurisdictions, and in English tort law in particular.
