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Cricket Nets
Cricket nets are used by batters and bowlers to practice their cricketing techniques. They consist of a cricket pitch (natural or artificial) enclosed by netting on either side, behind, and optionally above. The bowling end is left open. Nets stop the cricket ball travelling across the field when the batter plays a shot. They save practice time and eliminate the need for fielders or a wicket-keeper. They allow more people to train at once, particularly when they have several lanes. They allow solitary batting practice when used with a bowling machine. Use Nets are fundamental to cricket practice and are used at every level of the game. Professional cricket clubs are likely to have over 10 lanes of nets, and be able to practice both indoors and outdoors. Nets are also very prevalent in educational establishments, as they allow safe and efficient training with a high volume of pupils when there are significant time constraints. Keen cricketers may have nets in their gard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollock In Nets
Pollock or pollack (pronounced ) is the common name used for either of the two species of North Atlantic marine fish in the genus ''Pollachius''. ''Pollachius pollachius'' is referred to as "pollock" in North America, Ireland and the United Kingdom, while ''Pollachius virens'' is usually known as saithe or coley in Great Britain and Ireland (derived from the older name coalfish). Other names for ''P. pollachius'' include the Atlantic pollock, European pollock, ''lieu jaune'', and lythe or lithe; while ''P. virens'' is also known as Boston blue (distinct from bluefish) and silver bill. Species The recognized species in this genus are: * ''Pollachius pollachius'' (Linnaeus, 1758) (pollack) * ''Pollachius virens'' (Linnaeus, 1758) (coalfish) Description Both species can grow to . ''P. virens'' can weigh up to and ''P. pollachius'' can weigh up to . ''P. virens'' has a strongly defined, silvery lateral line running down the sides. Above the lateral li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galvanised Steel
Hot-dip galvanization is a form of galvanization. It is the process of coating iron and steel with zinc, which alloys with the surface of the base metal when immersing the metal in a bath of molten zinc at a temperature of around . When exposed to the atmosphere, the pure zinc (Zn) reacts with oxygen ( O2) to form zinc oxide ( ZnO), which further reacts with carbon dioxide ( CO2) to form zinc carbonate ( ZnCO3), a usually dull grey, fairly strong material that protects the steel underneath from further corrosion in many circumstances. Galvanized steel is widely used in applications where corrosion resistance is needed without the cost of stainless steel, and is considered superior in terms of cost and life-cycle. It can be identified by the crystallization patterning on the surface (often called a "spangle"). Galvanized steel can be welded; however, one must exercise caution around the resulting toxic zinc fumes. Galvanized fumes are released when the galvanized metal reaches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baseball
Baseball is a bat-and-ball games, bat-and-ball sport played between two team sport, teams of nine players each, taking turns batting (baseball), batting and Fielding (baseball), fielding. The game occurs over the course of several Pitch (baseball), plays, with each play beginning when a player on the fielding team (baseball), fielding team, called the pitcher, throws a Baseball (ball), ball that a player on the batting team (baseball), batting team, called the Batter (baseball), batter, tries to hit with a baseball bat, bat. The objective of the offensive team (batting team) is to hit the ball into the field of play, away from the other team's players, allowing its players to run the Base (baseball), bases, having them advance counter-clockwise around four bases to score what are called "Run (baseball), runs". The objective of the defensive team (referred to as the fielding team) is to prevent batters from becoming Base running, runners, and to prevent runners base running ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UV Stabilized
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. These interacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, cups, jars, etc.). , over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market. Many kinds of polyethylene are known, with most having the chemical formula (C2H4)''n''. PE is usually a mixture of similar polymers of ethylene, with various values of ''n''. It can be ''low-density'' or ''high-density'' and many variations thereof. Its properties can be modified further by crosslinking or copolymerization. All forms are nontoxic as well as chemically resilient, contributing to polyethylene's popularity as a multi-use plastic. However, polyethylene's chemical resilience also makes it a long-lived and decomposition-resistant pollutant when disposed of improperly. Being a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twine
Twine is a strong Thread (yarn), thread, light String (structure), string or cord composed of string in which two or more thinner strands are twisted, and then twisted together (Plying, plied). The strands are plied in the opposite direction to that of their twist, which adds torsional strength to the cord and keeps it from unravelling. This process is sometimes called reverse wrap. The same technique used for making twine is also used to make Thread (yarn), thread, which is thinner, yarn, and rope, which is stronger and thicker, generally with three or more strands. Natural fibres used for making twine include wool, cotton, sisal, jute, hemp, henequen, paper, and coir. A variety of synthetic fibres are also used. Twine is a popular substance used in modern-day crafting. Prehistoric The invention of twine is at least as important as the development of Stone tool, stone tools for early humans. Indeed, Elizabeth Wayland Barber has called the development of twine, which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulley System
Sheave without a rope A pulley is a wheel on an axle or shaft enabling a taut cable or belt passing over the wheel to move and change direction, or transfer power between itself and a shaft. A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain. History The earliest evidence of pulleys dates back to Ancient Egypt in the Twelfth Dynasty (1991–1802 BC) and Mesopotamia in the early 2nd millennium BC. In Roman Egypt, Hero of Alexandria (c. 10–70 AD) identified the pulley as one of six simple machines used to lift weights. Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another. Plutarch's ''Parallel Lives'' recounts a scene where Archimedes proved the effectiven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sports Hall
An arena is a large enclosed venue, often circular or oval-shaped, designed to showcase theatre, musical performances or sporting events. It comprises a large open space surrounded on most or all sides by tiered seating for spectators, and may be covered by a roof. The key feature of an arena is that the event space is the lowest point, allowing maximum visibility. Arenas are usually designed to accommodate a multitude of spectators. Background The word derives from Latin ', a particularly fine-grained sand that covered the floor of ancient arenas such as the Colosseum in Rome, Italy, to absorb blood.. The term ''arena'' is sometimes used as a synonym for a very large venue such as Pasadena's Rose Bowl, but such a facility is typically called a ''stadium''. The use of one term over the other has mostly to do with the type of event. Football (be it association, rugby, gridiron, Australian rules, or Gaelic) is typically played in a stadium, while basketball, volleyball, ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowler (cricket)
Bowling, in cricket, is the action of throwing, propelling the cricket ball, ball toward the wicket defended by a batter. A player skilled at bowling is called a ''bowler''; a bowler who is also a competent :Batting (cricket), batter is known as an all-rounder. Bowling the ball is distinguished from throwing (cricket), ''throwing'' the ball by a strictly specified biomechanical definition, which restricts the angle of extension of the elbow. A single act of bowling the ball towards the batter is called a ''ball'' or a ''delivery (cricket), delivery''. Bowlers bowl deliveries in sets of six, called an ''over (cricket), over''. Once a bowler has bowled an over, a teammate will bowl an over from the other end of the pitch. The Laws of Cricket govern how a ball must be bowled. If a ball is bowled illegally, an umpire (cricket), umpire will rule it a ''no-ball''. If a ball is bowled too wide of the striker for the batter to be able to play at it with a proper cricket shot, the bowler' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowling Machine
In cricket, a bowling machine is a device which enables a batter to practise (usually in the nets) and to hone specific skills through repetition of the ball being bowled at a certain length, line and speed. It can also be used when there is no-one available to bowl, or no one of the desired style or standard. There are a number of different types of bowling machine available to cricket coaches, each quite different in the ways they achieve the required delivery, though most allow the use of remote control, so that a coach can be closer to a batsman when the stroke is played. Ball-throwing machines for cricket have been used for over a century and originally followed a more slingshot design, which later gave way to motorised wheels and programmable machines. Mechanical bowling machines This type of machine is by far the most common. It is simple, strong and reliable, as well as being able to bowl a useful range of deliveries. How they work The main mechanism of the machi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
