116-947: The ITTF Challenge Series was an annual series of table tennis tournaments organised by the International Table Tennis Federation (ITTF). Initially created in 2013 as the third tier of the ITTF World Tour (below the Super Series and Major Series), the Challenge Series became a separate tour in 2017. It was the ITTF's secondary tour, below the World Tour. Starting from 2019, the series had two tiers: ITTF Challenge Plus and ITTF Challenge. Canada , Nigeria , North Korea , Oman , Paraguay , and Portugal were announced as host for
232-403: A backhand stroke (most often topspin) known as a reverse penhold backhand by turning the traditional side of the racket to face one's self, and striking the ball with the opposite side of the racket. This stroke has greatly improved and strengthened the penhold style both physically and psychologically, as it eliminates the strategic weakness of the traditional penhold backhand. The shakehand grip
348-792: A cultivar of the Kazakh dandelion ( Taraxacum kok-saghyz ) that is suitable for commercial production of natural rubber. In collaboration with Continental Tires , IME began a pilot facility. Many other plants produce forms of latex rich in isoprene polymers, though not all produce usable forms of polymer as easily as the Pará. Some of them require more elaborate processing to produce anything like usable rubber, and most are more difficult to tap. Some produce other desirable materials, for example gutta-percha ( Palaquium gutta ) and chicle from Manilkara species. Others that have been commercially exploited, or at least showed promise as rubber sources, include
464-447: A fiber, sometimes called 'elastic', had significant value to the textile industry because of its excellent elongation and recovery properties. For these purposes, manufactured rubber fiber was made as either an extruded round fiber or rectangular fibers cut into strips from extruded film. Because of its low dye acceptance, feel and appearance, the rubber fiber was either covered by yarn of another fiber or directly woven with other yarns into
580-510: A form of assisted biological coagulation. Little care is taken to exclude twigs, leaves, and even bark from the lumps that are formed, which may also include tree lace. Earth scrap is material that gathers around the base of the tree. It arises from latex overflowing from the cut and running down the bark, from rain flooding a collection cup containing latex, and from spillage from tappers' buckets during collection. It contains soil and other contaminants, and has variable rubber content, depending on
696-752: A given strain, thereby increasing the elastic force constant and making the rubber harder and less extensible. Raw rubber storage depots and rubber processing can produce malodour that is serious enough to become a source of complaints and protest to those living in the vicinity. Microbial impurities originate during the processing of block rubber. These impurities break down during storage or thermal degradation and produce volatile organic compounds. Examination of these compounds using gas chromatography / mass spectrometry (GC/MS) and gas chromatography (GC) indicates that they contain sulfur, ammonia, alkenes , ketones , esters , hydrogen sulfide , nitrogen, and low-molecular-weight fatty acids (C2–C5). When latex concentrate
812-432: A petroleum refinery or other natural incineration processes, is sometimes used as an additive to rubber to improve its strength, especially in vehicle tires. During vulcanization, rubber's polyisoprene molecules (long chains of isoprene) are heated and cross-linked with molecular bonds to sulfur, forming a 3-D matrix. The optimal percentage of sulfur is approximately 10%. In this form, the polyisoprene molecules orientation
928-417: A player may have a rubber that provides much spin on one side of their racket, and one that provides no spin on the other. By flipping the racket in play, different types of returns are possible. To help a player distinguish between the rubber used by his opposing player, international rules specify that one side must be black while the other side must be a bright color clearly distinguishable from black and from
1044-402: A playing space of at least 14 m (45.9 ft) long by 7 m (23.0 ft) wide, and a height clearance of at least 5 m (16.4 ft). For wheelchair events, the minimums are 8 m (26.2 ft) long and 6 m (19.7 ft) wide. Players are equipped with a laminated wooden racket covered with rubber on one or two sides depending on the grip of the player. The ITTF uses
1160-435: A point where it shares properties of both; i.e., if it is heated and cooled, it is degraded but not destroyed. The final properties of a rubber item depend not just on the polymer, but also on modifiers and fillers, such as carbon black , factice , whiting and others. Rubber particles are formed in the cytoplasm of specialized latex-producing cells called laticifers within rubber plants. Rubber particles are surrounded by
1276-553: A round racket head, for a more over-the-table style of play. In contrast, another style, sometimes referred to as the Japanese/Korean penhold grip, involves splaying those three fingers out across the back of the racket, usually with all three fingers touching the back of the racket, rather than stacked upon one another. Sometimes a combination of the two styles occurs, wherein the middle, ring and fourth fingers are straight, but still stacked, or where all fingers may be touching
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#17327836095101392-421: A second time on receiver's side of the table so that the ball passes the net and touches the opponent's court, either directly or after touching the net assembly. Thereafter, the server and receiver must alternately make a return until the rally is over. Returning the serve is one of the most difficult parts of the game, as the server's first move is often the least predictable and thus most advantageous shot due to
1508-451: A significant amount of rubber. Gloves (medical, household, and industrial) and toy balloons were large consumers of rubber, although the type of rubber used is concentrated latex. Significant tonnage of rubber was used as adhesives in many manufacturing industries and products, although the two most noticeable were the paper and the carpet industries. Rubber was commonly used to make rubber bands and pencil erasers . Rubber produced as
1624-453: A single phospholipid membrane with hydrophobic tails pointed inward. The membrane allows biosynthetic proteins to be sequestered at the surface of the growing rubber particle, which allows new monomeric units to be added from outside the biomembrane, but within the lacticifer. The rubber particle is an enzymatically active entity that contains three layers of material, the rubber particle, a biomembrane and free monomeric units. The biomembrane
1740-406: A smash when the opponent has returned a ball that bounces too high or too close to the net. It is nearly always done with a forehand stroke. Smashing uses rapid acceleration to impart as much speed on the ball as possible so that the opponent cannot react in time. The racket is generally perpendicular to the direction of the stroke. Because the speed is the main aim of this shot, the spin on the ball
1856-457: A solid base for striking and quick lateral movement. Players may tailor their stance based upon their personal preferences, and alter it during the game based upon the specific circumstances. Table tennis strokes generally break down into offensive and defensive categories. Also known as speed drive, a direct hit on the ball propelling it forward back to the opponent. This stroke differs from speed drives in other racket sports like tennis because
1972-410: A standard steel block thereby having a coefficient of restitution of 0.89 to 0.92. As of 2015, balls are now made of a polymer instead of celluloid , colored white or orange, with a matte finish. The choice of ball color is made according to the table color and its surroundings. For example, a white ball is easier to see on a green or blue table than it is on a grey table. Manufacturers often indicate
2088-442: A stationary table, rather than the court on which players stand. Either individually or in teams of two, players take alternating turns returning a light, hollow ball over the table's net onto the opposing half of the court using small rackets until they fail to do so, which results in a point for the opponent. Play is fast, requiring quick reaction and constant attention, and is characterized by an emphasis on spin, which can affect
2204-507: A uniform bounce of about 23 cm (9.1 in) when a standard ball is dropped onto it from a height of 30 cm (11.8 in), or about 77%. The table or playing surface is uniformly dark colored and matte, divided into two halves by a net at 15.25 cm (6.0 in) in height. The ITTF approves only wooden tables or their derivates. Concrete tables with a steel net or a solid concrete partition are sometimes available in outside public spaces, such as parks. ITTF regulations require
2320-401: A wire that encircles the tree. This wire incorporates a spring so it can stretch as the tree grows. The latex is led into the cup by a galvanised "spout" knocked into the bark. Rubber tapping normally takes place early in the morning, when the internal pressure of the tree is highest. A good tapper can tap a tree every 20 seconds on a standard half-spiral system, and a common daily "task" size
2436-442: Is 25 cm (vertical) bark consumption per year. The latex-containing tubes in the bark ascend in a spiral to the right. For this reason, tapping cuts usually ascend to the left to cut more tubes. The trees drip latex for about four hours, stopping as latex coagulates naturally on the tapping cut, thus blocking the latex tubes in the bark. Tappers usually rest and have a meal after finishing their tapping work and then start collecting
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#17327836095102552-418: Is a natural polymer of isoprene (polyisoprene), and an elastomer (a stretchy polymer). Polymers are simply chains of molecules that can be linked together. Rubber is one of the few naturally occurring polymers and prized for its high stretch ratio, resilience, and water-proof properties. Other examples of natural polymers include tortoise shell , amber , and animal horn . When harvested, latex rubber takes
2668-415: Is between 450 and 650 trees. Trees are usually tapped on alternate or third days, although many variations in timing, length and number of cuts are used. "Tappers would make a slash in the bark with a small hatchet. These slanting cuts allowed latex to flow from ducts located on the exterior or the inner layer of bark ( cambium ) of the tree. Since the cambium controls the growth of the tree, growth stops if it
2784-469: Is buoyant and water-proof. Industrial demand for rubber-like materials began to outstrip natural rubber supplies by the end of the 19th century, leading to the synthesis of synthetic rubber in 1909 by chemical means. The major commercial source of natural rubber latex is the Amazonian rubber tree ( Hevea brasiliensis ), a member of the spurge family , Euphorbiaceae . Once native to Brazil,
2900-453: Is currently owned by Indian Industries, Inc. d/b/a Escalade Sports . The next major innovation was by James W. Gibb, a British table tennis enthusiast, who discovered novelty celluloid balls on a trip to the US in 1901 and found them ideal for the game. This was followed by E.C. Goode who, in 1901, invented the modern version of the racket by fixing a sheet of pimpled, or stippled, rubber to
3016-496: Is cut. Thus, rubber tapping demanded accuracy, so that the incisions would not be too many given the size of the tree, or too deep, which could stunt its growth or kill it." It is usual to tap a panel at least twice, sometimes three times, during the tree's life. The economic life of the tree depends on how well the tapping is carried out, as the critical factor is bark consumption. A standard in Malaysia for alternate daily tapping
3132-430: Is for the players to play the ball back and forth three times and then play out the point. This is commonly referred to as "serve to play", "rally to serve", "play for serve", or "volley for serve". Another common method is referred to as "Ping for serve" or "Pinging for serve" where players will begin playing by hitting or bouncing the ball and playing a rally spelling out the word ping P-I-N-G with each hit then playing out
3248-483: Is generally accepted that shakehands is easier to learn than penholder, allowing a broader range of playing styles both offensive and defensive. The Seemiller grip is named after the American table tennis champion Danny Seemiller , who used it. It is achieved by placing the thumb and index finger on either side of the bottom of the racquet head and holding the handle with the rest of the fingers. Since only one side of
3364-563: Is governed by the International Table Tennis Federation (ITTF), founded in 1926, and specifies the official rules in the ITTF handbook. ITTF currently includes 226 member associations worldwide. The sport originated in Victorian England , where it was played among the upper-class as an after-dinner parlour game . It has been suggested that makeshift versions of the game were developed by British military officers in India around
3480-438: Is held tightly to the rubber core by the high negative charge along the double bonds of the rubber polymer backbone. Free monomeric units and conjugated proteins make up the outer layer. The rubber precursor is isopentenyl pyrophosphate (an allylic compound), which elongates by Mg -dependent condensation by the action of rubber transferase. The monomer adds to the pyrophosphate end of the growing polymer. The process displaces
3596-572: Is low and strain results from small changes of bond lengths and angles: this caused the Challenger disaster , when the American Space Shuttle 's flattened o-rings failed to relax to fill a widening gap. The glass transition is fast and reversible: the force resumes on heating. The parallel chains of stretched rubber are susceptible to crystallization. This takes some time because turns of twisted chains have to move out of
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3712-899: Is not cultivated widely in its native continent of South America because of the South American leaf blight , and other natural predators there. Rubber latex is extracted from rubber trees. The economic life of rubber trees in plantations is around 32 years, with up to 7 years being an immature phase and about 25 years of productive phase. The soil requirement is well-drained, weathered soil consisting of laterite , lateritic types, sedimentary types, nonlateritic red or alluvial soils. The climatic conditions for optimum growth of rubber trees are: Many high-yielding clones have been developed for commercial planting. These clones yield more than 2,000 kilograms per hectare (1,800 lb/acre) of dry rubber per year, under ideal conditions. Rubber production has been linked to deforestation. Rubber therefore
3828-452: Is often minimal, although it can be applied as well. An offensive table tennis player will think of a rally as a build-up to a winning smash. Smash is used more often with penhold grip. The push (or "slice" in Asia) is usually used for keeping the point alive and creating offensive opportunities. A push resembles a tennis slice: the racket cuts underneath the ball, imparting backspin and causing
3944-588: Is one of seven commodities included in the 2023 EU Regulation on Deforestation-free products (EUDR), which aims to guarantee that the products European Union (EU) citizens consume do not contribute to deforestation or forest degradation worldwide. In places such as Kerala and Sri Lanka, where coconuts are in abundance, the half shell of coconut was used as the latex collection container. Glazed pottery or aluminium or plastic cups became more common in Kerala-India and other countries. The cups are supported by
4060-538: Is popular in Japan. The average size of the blade is about 17 centimetres (6.7 in) long and 15 centimetres (5.9 in) wide. Although the official restrictions only focus on the flatness and rigidity of the blade itself, these dimensions are optimal for most play styles. Table tennis regulations allow different rubber surfaces on each side of the racket. Various types of surfaces provide various levels of spin or speed, and in some cases they nullify spin. For example,
4176-449: Is produced by smallholders, who collect rubber from trees far from the nearest factory. Many Indonesian smallholders, who farm paddies in remote areas, tap dispersed trees on their way to work in the paddy fields and collect the latex (or the coagulated latex) on their way home. As it is often impossible to preserve the latex sufficiently to get it to a factory that processes latex in time for it to be used to make high quality products, and as
4292-529: Is produced from rubber, sulfuric acid is used for coagulation. This produces malodourous hydrogen sulfide. The industry can mitigate these bad odours with scrubber systems . Rubber is the polymer cis-1,4-polyisoprene – with a molecular weight of 100,000 to 1,000,000 daltons . Typically, a small percentage (up to 5% of dry mass) of other materials, such as proteins , fatty acids , resins , and inorganic materials (salts) are found in natural rubber. Polyisoprene can also be created synthetically, producing what
4408-422: Is refined into the rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for sale. Natural rubber is used extensively in many applications and products, either alone or in combination with other materials. In most of its useful forms, it has a large stretch ratio and high resilience and also
4524-462: Is so-named because one grips the racket similarly to the way one holds a writing instrument . The style of play among penhold players can vary greatly from player to player. The most popular style, usually referred to as the Chinese penhold style, involves curling the middle, ring, and fourth finger on the back of the blade with the three fingers always touching one another. Chinese penholders favour
4640-622: Is so-named because the racket is grasped as if one is performing a handshake. Though it is sometimes referred to as the "tennis" or "Western" grip, it bears no relation to the Western tennis grip , which was popularized on the West Coast of the United States in which the racket is rotated 90°, and played with the wrist turned so that on impact the knuckles face the target. In table tennis, "Western" refers to Western nations, for this
4756-567: Is sometimes applied to the tree-obtained version of natural rubber in order to distinguish it from the synthetic version. The first use of rubber was by the indigenous cultures of Mesoamerica . The earliest archeological evidence of the use of natural latex from the Hevea tree comes from the Olmec culture, in which rubber was first used for making balls for the Mesoamerican ballgame . Rubber
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4872-402: Is sometimes referred to as "synthetic natural rubber", but the synthetic and natural routes are distinct. Some natural rubber sources, such as gutta-percha , are composed of trans-1,4-polyisoprene, a structural isomer that has similar properties. Natural rubber is an elastomer and a thermoplastic . Once the rubber is vulcanized, it is a thermoset . Most rubber in everyday use is vulcanized to
4988-479: Is still random but they become aligned when the rubber is stretched. This sulfur vulcanization makes the rubber stronger and more rigid, but still very elastic. And through the vulcanization process, the sulfur and latex are meant to be totally used up in individual form. Natural rubber latex is shipped from factories in Southeast Asia , South America , and West and Central Africa to destinations around
5104-582: Is the grip that players native to Europe and the Americas have almost exclusively employed. The shakehand grip's simplicity and versatility, coupled with the acceptance among top-level Chinese trainers that the European style of play should be emulated and trained against, has established it as a common grip even in China. Many world-class European and East Asian players currently use the shakehand grip, and it
5220-410: Is usually a counterattack against drives, normally high loop drives. The racket is held closed and near to the ball, which is hit with a short movement "off the bounce" (immediately after hitting the table) so that the ball travels faster to the other side. Kenta Matsudaira is known for primarily using counter-hit for offense. When a player tries to attack a ball that has not bounced beyond the edge of
5336-538: The Chinese Civil War had a "passion for the English game of table tennis" which he found "bizarre". On the other hand, the popularity of the sport waned in the 1930s Soviet Union, partly because of the promotion of team and military sports, and partly because of a theory that the game had adverse health effects. In the 1950s, paddles that used a rubber sheet combined with an underlying sponge layer changed
5452-505: The Mullins effect and the Payne effect and is often modeled as hyperelastic . Rubber strain crystallizes . Because there are weakened allylic C-H bonds in each repeat unit , natural rubber is susceptible to vulcanisation as well as being sensitive to ozone cracking . The two main solvents for rubber are turpentine and naphtha (petroleum). Because rubber does not dissolve easily,
5568-728: The Putumayo genocide . Between the 1880s–1913 Julio César Arana and his company that would become the Peruvian Amazon Company controlled the Putumayo river. W.E. Hardenburg, Benjamin Saldaña Rocca and Roger Casement were influential figures in exposing these atrocities. Roger Casement was also prominent in revealing the Congo atrocities to the world. Days before entering Iquitos by boat Casement wrote "'Caoutchouc
5684-557: The cytosol . In plants, isoprene pyrophosphate can also be obtained from the 1-deox-D-xyulose-5-phosphate/2-C-methyl-D-erythritol-4-phosphate pathway within plasmids. The relative ratio of the farnesyl pyrophosphate initiator unit and isoprenyl pyrophosphate elongation monomer determines the rate of new particle synthesis versus elongation of existing particles. Though rubber is known to be produced by only one enzyme, extracts of latex host numerous small molecular weight proteins with unknown function. The proteins possibly serve as cofactors, as
5800-455: The 1860s or 1870s, who brought it back with them. A row of books stood up along the center of the table as a net, two more books served as rackets and were used to continuously hit a golf-ball. In 1883, British sporting goods company Slazenger filed a patent for a net for table tennis. The name "ping-pong" was in wide use before British manufacturer J. Jaques & Son Ltd trademarked it in 1901. The name "ping-pong" then came to describe
5916-490: The 1960s, the loop is essentially the reverse of the chop. The racket is parallel to the direction of the stroke ("closed") and the racket thus grazes the ball, resulting in a large amount of topspin. A good loop drive will arc quite a bit, and once striking the opponent's side of the table will jump forward, much like a kick serve in tennis. Most professional players nowadays, such as Ding Ning , Timo Boll and Zhang Jike , primarily use loop for offense. The counter-hit
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#17327836095106032-457: The Académie (published in 1755) that described many of rubber's properties. This has been referred to as the first scientific paper on rubber. In England, Joseph Priestley , in 1770, observed that a piece of the material was extremely good for rubbing off pencil marks on paper, hence the name "rubber". It slowly made its way around England. In 1764, François Fresnau discovered that turpentine
6148-611: The Challenge Plus tournaments for the 2019 season. Since 2021, the ITTF Challenge Series has been effectively replaced by the newly created World Table Tennis Feeder Series. The following tournaments have featured as part of the ITTF Challenge Series since it separated from the ITTF World Tour in 2017. Table tennis Table tennis (also known as ping-pong ) is a racket sport derived from tennis but distinguished by its playing surface being atop
6264-673: The Congo Free State for more information on the rubber trade in the Congo Free State in the late 1800s and early 1900s.) The rubber boom in the Amazon also similarly affected indigenous populations to varying degrees. Correrias, or slave raids were frequent in Colombia, Peru and Bolivia where many were either captured or killed. The most well known case of atrocities generated from rubber extraction in South America came from
6380-525: The ITTF handbook, which was first published in 1927. The current (fiftieth) version was published in 2022. After the 2000 Olympics in Sydney , the ITTF instituted several rule changes that were aimed at making table tennis more viable as a televised spectator sport. First, the older 38 mm (1.50 in) balls were officially replaced by 40 mm (1.57 in) balls in October 2000. This increased
6496-564: The Olympic Games since 1988 and the Commonwealth Games since 2002. In doubles, all the rules of single play are applied except for the following. Service Order of play, serving and receiving If a game is unfinished after 10 minutes of play and fewer than 18 points have been scored, the expedite system is initiated. The umpire interrupts the game, and the game resumes with players serving for one point in turn. If
6612-470: The United States' five participants in the World Championships used it. 'A good ready position will enable you to move quickly into position and to stay balanced whilst playing powerful strokes.' The stance in table tennis is also known as the 'ready position'. It is the position every player initially adopts when receiving and returns to after playing a shot in order to be prepared to make
6728-405: The air. The ITTF states that all events after July 2014 are played with a new poly material ball. The international rules specify that the game is played with a sphere having a mass of 2.7 grams (0.095 oz) and a diameter of 40 millimetres (1.57 in). The rules say that the ball shall bounce up 24–26 cm (9.4–10.2 in) when dropped from a height of 30.5 cm (12.0 in) onto
6844-409: The amount of contaminants. Earth scrap is collected by field workers two or three times a year and may be cleaned in a scrap-washer to recover the rubber, or sold to a contractor who cleans it and recovers the rubber. It is of low quality. Latex coagulates in the cups if kept for long and must be collected before this happens. The collected latex, "field latex", is transferred into coagulation tanks for
6960-545: The back of the racket, but are also in contact with one another. Japanese and Korean penholders will often use a square-headed racket for an away-from-the-table style of play. Traditionally these square-headed rackets feature a block of cork on top of the handle, as well as a thin layer of cork on the back of the racket, for increased grip and comfort. Penhold styles are popular among players originating from East Asian countries such as China , Japan , South Korea , and Taiwan . Traditionally, penhold players use only one side of
7076-468: The ball to float slowly to the other side of the table. A push can be difficult to attack because the backspin on the ball causes it to drop toward the table upon striking the opponent's racket. In order to attack a push, a player must usually loop (if the push is long) or flip (if the push is short) the ball back over the net. Often, the best option for beginners is to simply push the ball back again, resulting in pushing rallies. Against good players, it may be
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#17327836095107192-477: The ball's air resistance and effectively slowed down the game. By that time, players had begun increasing the thickness of the fast sponge layer on their paddles, which made the game excessively fast and difficult to watch on television. A few months later, the ITTF changed from a 21-point to an 11-point scoring system (and the serve rotation was reduced from five points to two), effective in September 2001. This
7308-521: The ball's trajectory more than in other ball sports. Owed to its small minimum playing area, its ability to be played indoors in all climates, and relative accessibility of equipment, table tennis is enjoyed worldwide not just as a competitive sport, but as a common recreational pastime among players of all levels and ages. Table tennis has been an Olympic sport since 1988 , with event categories in both men's and women's singles, and men's and women's teams since replacing doubles in 2008 . Table tennis
7424-433: The color of the ball. The player has the right to inspect their opponent's racket before a match to see the type of rubber used and what color it is. Despite high-speed play and rapid exchanges, a player can see clearly what side of the racket was used to hit the ball. Current rules state that, unless damaged in play, the racket cannot be exchanged for another racket at any time during a match. According to ITTF rule 2.13.1,
7540-407: The dry rubber produced. Latex that drips onto the ground, "earth scrap", is also collected periodically for processing of low-grade product. Cup lump is the coagulated material found in the collection cup when the tapper next visits the tree to tap it again. It arises from latex clinging to the walls of the cup after the latex was last poured into the bucket, and from late-dripping latex exuded before
7656-666: The early 1900s, the Congo Free State in Africa was also a significant source of natural rubber latex, mostly gathered by forced labor . King Leopold II's colonial state brutally enforced production quotas due to the high price of natural rubber at the time. Tactics to enforce the rubber quotas included removing the hands of victims to prove they had been killed. Soldiers often came back from raids with baskets full of chopped-off hands. Villages that resisted were razed to encourage better compliance locally. (See Atrocities in
7772-403: The expedite system is introduced while the ball is not in play, the previous receiver shall serve first. Under the expedite system, the server must win the point before the opponent makes 13 consecutive returns or the point goes to the opponent. The system can also be initiated at any time at the request of both players or pairs. Once introduced, the expedite system remains in force until the end of
7888-421: The export of seeds or plants. In 1876, Henry Wickham smuggled 70,000 Amazonian rubber tree seeds from Brazil and delivered them to Kew Gardens , England. Only 2,400 of these germinated. Seedlings were then sent to India , British Ceylon ( Sri Lanka ), Dutch East Indies ( Indonesia ), Singapore , and British Malaya . Malaya (now Peninsular Malaysia ) was later to become the biggest producer of rubber. In
8004-636: The fabric. Rubber yarns were used in foundation garments. While rubber is still used in textile manufacturing, its low tenacity limits its use in lightweight garments because latex lacks resistance to oxidizing agents and is damaged by aging, sunlight, oil and perspiration. The textile industry turned to neoprene (polymer of chloroprene ), a type of synthetic rubber, as well as another more commonly used elastomer fiber, spandex (also known as elastane), because of their superiority to rubber in both strength and durability. Rubber exhibits unique physical and chemical properties. Rubber's stress–strain behavior exhibits
8120-426: The first service is decided by lot, normally a coin toss . It is also common for one player (or the umpire/scorer) to hide the ball in one or the other hand, usually hidden under the table, allowing the other player to guess which hand the ball is in. The correct or incorrect guess gives the "winner" the option to choose to serve, receive, or to choose which side of the table to use. (A common but non-sanctioned method
8236-477: The first technique for tapping trees for latex without causing serious harm to the tree. Because of his fervent promotion of this crop, he is popularly remembered by the nickname "Mad Ridley". Before World War II significant uses included door and window profiles, hoses, belts, gaskets, matting , flooring, and dampeners (antivibration mounts) for the automotive industry. The use of rubber in car tires (initially solid rather than pneumatic) in particular consumed
8352-544: The form of latex, an opaque, white, milky suspension of rubber particles in water. It is then transformed through industrial processes to the solid form widely seen in manufactured goods. Natural rubber is reactive and vulnerable to oxidization, but it can be stabilized through a heating process called vulcanization. Vulcanization is a process by which the rubber is heated and sulfur , peroxide , or bisphenol are added to improve resistance and elasticity and to prevent it from oxidizing. Carbon black , which can be derived from
8468-482: The game dramatically, introducing greater spin and speed. These were introduced to Britain by sports goods manufacturer S.W. Hancock Ltd. The use of speed glue beginning in the mid-1980s increased the spin and speed even further, resulting in changes to the equipment to "slow the game down". Table tennis was introduced as an Olympic sport at the Olympics in 1988 . The official rules and regulations are specified in
8584-462: The game played using the rather expensive Jaques's equipment, with other manufacturers calling it table tennis. A similar situation arose in the United States, where Jaques sold the rights to the "ping-pong" name to Parker Brothers . Parker Brothers then enforced its trademark for the term in the 1920s, making the various associations change their names to "table tennis" instead of the more common, but trademarked, term. The U.S. trademark for "Ping-Pong"
8700-459: The higher-grade, technically specified block rubbers such as SVR 3L or SVR CV or used to produce Ribbed Smoke Sheet grades. Naturally coagulated rubber (cup lump) is used in the manufacture of TSR10 and TSR20 grade rubbers. Processing for these grades is a size reduction and cleaning process to remove contamination and prepare the material for the final stage of drying. The dried material is then baled and palletized for storage and shipment. Rubber
8816-431: The international market spot price of a seemingly more profitable crop (for example palm oil ) surges in relation to rubber. For instance, during the 2020 and 2021 international COVID-19 pandemic , demand for rubber gloves surged, leading to a spike in rubber prices of about 30%. In addition to the pandemic, demand exceeded supply in part because long term plantations had been torn out and replaced with other crops over
8932-402: The latex would anyway have coagulated by the time it reached the factory, the smallholder will coagulate it by any means available, in any container available. Some smallholders use small containers, buckets etc., but often the latex is coagulated in holes in the ground, which are usually lined with plastic sheeting. Acidic materials and fermented fruit juices are used to coagulate the latex –
9048-434: The latex-carrying vessels of the tree become blocked. It is of higher purity and of greater value than the other three types. 'Cup lumps' can also be used to describe a completely different type of coagulate that has collected in smallholder plantations over a period of 1–2 weeks. After tapping all of the trees, the tapper will return to each tree and stir in some type of acid, which allows the newly harvested latex to mix with
9164-416: The latex. There is growing concern for the future supply of rubber due to various factors, including plant disease, climate change, and the volatile market price of rubber. Producers of natural rubber are mostly small family-held plantations, often serving large industrial aggregators. High volatility in the price of rubber affects rubber plantation investment, and farmers may remove their rubber trees if
9280-472: The leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers . Currently, rubber is harvested mainly in the form of the latex from the Pará rubber tree ( Hevea brasiliensis ) or others. The latex is a sticky, milky and white colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex then
9396-443: The liquid "field latex" at about midday. The four types of field coagula are "cuplump", "treelace", "smallholders' lump", and "earth scrap". Each has significantly different properties. Some trees continue to drip after the collection leading to a small amount of "cup lump" that is collected at the next tapping. The latex that coagulates on the cut is also collected as "tree lace". Tree lace and cup lump together account for 10%–20% of
9512-461: The match. As it is intended as a rule to shorten the duration of a match, it is mainly deployed in defensive players' matches, which tend to have longer points. Though table tennis players grip their rackets in various ways, their grips can be classified into two major families of styles, penhold and shakehand . The rules of table tennis do not prescribe the manner in which one must grip the racket, and numerous grips are employed. The penhold grip
9628-399: The material is finely divided by shredding prior to its immersion. An ammonia solution can be used to prevent the coagulation of raw latex. Rubber begins to melt at approximately 180 °C (356 °F). On a microscopic scale, relaxed rubber is a disorganized cluster of erratically changing wrinkled chains. In stretched rubber, the chains are almost linear. The restoring force is due to
9744-413: The next shot. It involves the feet being spaced wider than shoulder width and a partial crouch being adopted; the crouch is an efficient posture for moving quickly from and also preloads the muscles enabling a more dynamic movement. The upper torso is positioned slightly forward and the player is looking forwards. The racket is held at the ready with a bent arm. The position should feel balanced and provide
9860-415: The numerous spin and speed choices at the server's disposal. A let is a rally of which the result is not scored, and is called in the following circumstances: A let is also called foul service, if the ball hits the server's side of the table, if the ball does not pass further than the edge, and if the ball hits the table edge and hits the net. A point is scored by the player for any of several results of
9976-424: The opponent and the umpire must have a clear view of the ball at all times. If the umpire is doubtful of the legality of a service they may first interrupt play and give a warning to the server. If the serve is a clear failure or is doubted again by the umpire after the warning, the receiver scores a point. If the service is "good", then the receiver must make a "good" return by hitting the ball back before it bounces
10092-577: The plantation expanded to Karnataka , Tamil Nadu and the Andaman and Nicobar Islands of India. Today, India is the world's 3rd largest producer and 4th largest consumer of rubber. In Singapore and Malaya, commercial production was heavily promoted by Sir Henry Nicholas Ridley , who served as the first Scientific Director of the Singapore Botanic Gardens from 1888 to 1911. He distributed rubber seeds to many planters and developed
10208-432: The point for service). In game play, the player serving the ball commences a play. The server first stands with the ball held on the open palm of the hand not carrying the paddle, called the freehand, and tosses the ball directly upward without spin, at least 16 cm (6.3 in) high. The server strikes the ball with the racket on the ball's descent so that it first touches the server's court, and then touches directly
10324-606: The preparation of dry rubber or transferred into air-tight containers with sieving for ammoniation. Ammoniation, invented by patent lawyer and vice-president of the United States Rubber Company Ernest Hopkinson around 1920, preserves the latex in a colloidal state for longer periods of time. Latex is generally processed into either latex concentrate for manufacture of dipped goods or coagulated under controlled, clean conditions using formic acid. The coagulated latex can then be processed into
10440-400: The preponderance of wrinkled conformations over more linear ones. For the quantitative treatment see ideal chain , for more examples see entropic force . Cooling below the glass transition temperature permits local conformational changes but a reordering is practically impossible because of the larger energy barrier for the concerted movement of longer chains. "Frozen" rubber's elasticity
10556-422: The previously coagulated material. The rubber/acid mixture is what gives rubber plantations, markets, and factories a strong odor. Tree lace is the coagulum strip that the tapper peels off the previous cut before making a new cut. It usually has higher copper and manganese contents than cup lump. Both copper and manganese are pro-oxidants and can damage the physical properties of the dry rubber. Smallholders' lump
10672-404: The quality of the ball with a star rating system, usually from one to three, three being the highest grade. As this system is not standard across manufacturers, the only way a ball may be used in official competition is upon ITTF approval (the ITTF approval can be seen printed on the ball). The 40 mm ball was introduced after the end of the 2000 Summer Olympics ; previously a 38 mm ball
10788-432: The racket is primarily perpendicular to the direction of the stroke and most of the energy applied to the ball results in speed rather than spin , creating a shot that does not arc much, but is fast enough that it can be difficult to return. A speed drive is used mostly for keeping the ball in play, applying pressure on the opponent, and potentially opening up an opportunity for a more powerful attack. Perfected during
10904-464: The racket to hit the ball during normal play, and the side which is in contact with the last three fingers is generally not used. This configuration is sometimes referred to as "traditional penhold" and is more commonly found in square-headed racket styles. However, the Chinese developed a technique in the 1990s in which a penholder uses both sides of the racket to hit the ball, where the player produces
11020-542: The racquet is used to hit the ball, two contrasting rubber types can be applied to the blade, offering the advantage of "twiddling" the racket to fool the opponent. Seemiller paired inverted rubber with anti-spin rubber. Many players today combine inverted and long-pipped rubber. The grip is considered exceptional for blocking, especially on the backhand side, and for forehand loops of backspin balls. The Seemiller grip's popularity reached its apex in 1985 when four (Danny Seemiller, Ricky Seemiller, Eric Boggan and Brian Masters) of
11136-413: The rally) until the end of the game, unless both players score ten points or the expedite system is operated, when the sequences of serving and receiving stay the same but each player serves for only one point in turn (Deuce). The player serving first in a game receives first in the next game of the match. After each game, players switch sides of the table. In the last possible game of a match, for example
11252-412: The rally: A game shall be won by the player first scoring 11 points unless both players score 10 points, when the game shall be won by the first player subsequently gaining a lead of 2 points. A match shall consist of the best of any odd number of games. In competition play, matches are typically best of five or seven games. Service alternates between opponents every two points (regardless of winner of
11368-399: The receiver's court without touching the net assembly. In casual games, many players do not toss the ball upward; however, this is technically illegal and can give the serving player an unfair advantage. The ball must remain behind the endline and above the playing surface of the table at all times during the service. The server's body or clothing cannot be used to obstruct sight of the ball;
11484-420: The rubber fig ( Ficus elastica ), Panama rubber tree ( Castilla elastica ), various spurges ( Euphorbia spp.), lettuce ( Lactuca species), the related Scorzonera tau-saghyz , various Taraxacum species, including common dandelion ( Taraxacum officinale ) and Kazakh dandelion, and, perhaps most importantly for its hypoallergenic properties, guayule ( Parthenium argentatum ). The term gum rubber
11600-580: The same quality as the natural rubber from rubber trees . In the wild types of dandelion, latex content is low and varies greatly. In Nazi Germany , research projects tried to use dandelions as a base for rubber production, but failed. In 2013, by inhibiting one key enzyme and using modern cultivation methods and optimization techniques, scientists in the Fraunhofer Institute for Molecular Biology and Applied Ecology (IME) in Germany developed
11716-530: The seventh game in a best of seven match, players change ends when the first player scores five points, regardless of whose turn it is to serve. If the sequence of serving and receiving is out of turn or the ends are not changed, points scored in the wrong situation are still calculated and the game shall be resumed with the order at the score that has been reached. In addition to games between individual players, pairs may also play table tennis. Singles and doubles are both played in international competition, including
11832-454: The species is now pan-tropical. This species is preferred because it grows well under cultivation. A properly managed tree responds to wounding by producing more latex for several years. Congo rubber , formerly a major source of rubber, which motivated the atrocities in the Congo Free State , came from vines in the genus Landolphia ( L. kirkii , L. heudelotis , and L. owariensis ). Dandelion milk contains latex. The latex exhibits
11948-564: The synthetic rate decreases with complete removal. More than 28 million tons of rubber were produced in 2017, of which approximately 47% was natural. Since the bulk is synthetic, which is derived from petroleum, the price of natural rubber is determined, to a large extent, by the prevailing global price of crude oil. Asia was the main source of natural rubber, accounting for about 90% of output in 2021. The three largest producers, Thailand , Indonesia, and Malaysia, together account for around 72% of all natural rubber production. Natural rubber
12064-443: The table, the player does not have the room to wind up in a backswing . The ball may still be attacked , however, and the resulting shot is called a flip because the backswing is compressed into a quick wrist action. A flip is not a single stroke and can resemble either a loop drive or a loop in its characteristics. What identifies the stroke is that the backswing is compressed into a short wrist flick. A player will typically execute
12180-543: The term "racket", though "bat" is common in Britain, and "paddle" in the U.S. and Canada. The wooden portion of the racket, often referred to as the "blade", commonly features anywhere between one and seven plies of wood, though cork, glass fiber, carbon fiber, aluminum fiber, and Kevlar are sometimes used. According to the ITTF regulations, at least 85% of the blade by thickness shall be of natural wood. Common wood types include balsa , limba , cypress , and hinoki , which
12296-435: The terminal high-energy pyrophosphate. The reaction produces a cis polymer. The initiation step is catalyzed by prenyltransferase , which converts three monomers of isopentenyl pyrophosphate into farnesyl pyrophosphate . The farnesyl pyrophosphate can bind to rubber transferase to elongate a new rubber polymer. The required isopentenyl pyrophosphate is obtained from the mevalonate pathway, which derives from acetyl-CoA in
12412-453: The way of the growing crystallites . Crystallization has occurred, for example, when, after days, an inflated toy balloon is found withered at a relatively large remaining volume. Where it is touched, it shrinks because the temperature of the hand is enough to melt the crystals. Vulcanization of rubber creates di- and polysulfide bonds between chains, which limits the degrees of freedom and results in chains that tighten more quickly for
12528-414: The wooden blade. Table tennis was growing in popularity by 1901 to the extent that tournaments were being organized, books were being written on the subject, and an unofficial world championship was held in 1902. In those early days, the scoring system was the same as in lawn tennis . Although both a "Table Tennis Association" and a "Ping Pong Association" existed by 1910, a new Table Tennis Association
12644-442: The world. As the cost of natural rubber has risen significantly and rubber products are dense, the shipping methods offering the lowest cost per unit weight are preferred. Depending on destination, warehouse availability, and transportation conditions, some methods are preferred by certain buyers. In international trade, latex rubber is mostly shipped in 20-foot ocean containers. Inside the container, smaller containers are used to store
12760-532: The worst option because the opponent will counter with a loop, putting the first player in a defensive position. Pushing can have advantages in some circumstances, such as when the opponent makes easy mistakes. Natural rubber Rubber , also called India rubber , latex , Amazonian rubber , caucho , or caoutchouc , as initially produced, consists of polymers of the organic compound isoprene , with minor impurities of other organic compounds. Thailand , Malaysia , Indonesia , and Cambodia are four of
12876-468: Was a rubber solvent . Giovanni Fabbroni is credited with the discovery of naphtha as a rubber solvent in 1779. Charles Goodyear redeveloped vulcanization in 1839, although Mesoamericans had used stabilized rubber for balls and other objects as early as 1600 BC. South America remained the main source of latex rubber used during much of the 19th century. The rubber trade was heavily controlled by business interests but no laws expressly prohibited
12992-760: Was first called 'india rubber,' because it came from the Indies, and the earliest European use of it was to rub out or erase. It is now called India rubber because it rubs out or erases the Indians." In India , commercial cultivation was introduced by British planters, although the experimental efforts to grow rubber on a commercial scale were initiated as early as 1873 at the Calcutta Botanical Garden . The first commercial Hevea plantations were established at Thattekadu in Kerala in 1902. In later years
13108-717: Was founded in 1921, and renamed the English Table Tennis Association in 1926. The International Table Tennis Federation (ITTF) followed in 1926. London hosted the first official World Championships in 1926. In 1933, the United States Table Tennis Association , now called USA Table Tennis, was formed. In the 1930s, Edgar Snow commented in Red Star Over China that the Communist forces in
13224-400: Was intended to make games more fast-paced and exciting. The ITTF also changed the rules on service to prevent a player from hiding the ball during service, in order to increase the average length of rallies and to reduce the server's advantage, effective in 2002. For the opponent to have time to realize a serve is taking place, the ball must be tossed a minimum of 16 centimetres (6.3 in) in
13340-529: Was later used by the Maya and Aztec cultures: in addition to making balls, Aztecs used rubber for other purposes, such as making containers and to make textiles waterproof by impregnating them with the latex sap. Charles Marie de La Condamine is credited with introducing samples of rubber to the Académie Royale des Sciences of France in 1736. In 1751, he presented a paper by François Fresneau to
13456-522: Was standard. This created some controversies. Vladimir Samsonov , the World No. 1 table tennis professional at the time, threatened to pull out of the World Cup, which was scheduled to debut the new regulation ball on 12 October 2000. The table is 2.74 m (9.0 ft) long, 1.525 m (5.0 ft) wide, and 76 cm (2.5 ft) high with any continuous material so long as the table yields
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