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Dumb-bell (aviation)
The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs, with one in each hand. History The forerunner of the dumbbell, halteres, were used in ancient Greece as lifting weights and also as weights in the ancient Greek version of the long jump. A kind of dumbbell was also used in India for more than a millennium, shaped like a club – so it was named Indian club. The design of the "Nal", as the equipment was referred to, can be seen as a halfway point between a barbell and a dumbbell. It was generally used in pairs, in workouts by wrestlers, bodybuilders, sports players, and others wishing to increase strength and muscle size. Etymology The term "dumbbell" or "dumb bell" originated in late Stuart England. In 1711 the poet Joseph Addison mentioned exercising with a "dumb bell" in an essay published in ''The Spectator''. Although Addison elsewhere in the same publication describes having used equipment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbell
A barbell is a piece of exercise equipment used in weight training, bodybuilding, weightlifting, powerlifting and strongman, consisting of a long bar, usually with weights attached at each end. Barbells range in length from to above , although bars longer than are used primarily by powerlifters and are not commonplace. The central portion of the bar varies in diameter from 25 millimetres (0.98 in) to 50 millimetres (1.96 in) (e.g., Apollon's Axle), and is often engraved with a knurled crosshatch pattern to help lifters maintain a solid grip. Weight plates slide onto the outer portions of the bar to increase or decrease the desired total weight. Collars are used to prevent plates from moving outward unevenly so that the lifter does not experience uneven force. The barbell is the longer version of the dumbbell that is used for free weight training and competitive sports, such as powerlifting, Olympic weight lifting, and CrossFit. Many exercises can be done using th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jan Todd
Janice Todd (''née'' Suffolk; born May 22, 1952) is a Professor and Interim Department Chair (starting August, 2022) in the Department of Kinesiology and Health Education at The University of Texas at Austin. Todd is a member of the Sport Management faculty, and teaches classes in sport history, sport philosophy, and sport and ethics. An active lecturer, Todd was named the Seward Staley Honor Lecturer for the North American Society for Sport History in 2008. Dinnie Stones Janice Todd is perhaps best known outside the powerlifting community for being the first woman ever to successfully lift the Dinnie Stones in 1979. This feat was not replicated again until 2018, by Leigh Holland-Keen. Powerlifting career Todd’s interest in the study of sport and physical culture was galvanized by her participation and success in the sport of powerlifting. During her powerlifting career, many publications—including ''Sports Illustrated'' magazine – considered her to be the strongest woma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weight Plate
A weight plate is a flat, heavy object, usually made of cast iron, that is used in combination with barbells or dumbbells to produce a bar with a desired total weight for the purpose of physical exercise. Two general categories exist: "standard" plates, which have a center hole of approximately 25 mm (one inch), and "Olympic" plates, meant to fit on the 50 mm (two inches) sleeves of Olympic barbells. Standard plates are usually paired with adjustable dumbbells and Olympic plates with full-size barbells, although standard barbells and Olympic dumbbells exist. Weight plates may incorporate holes for ease of carrying (called "grip plates") or be solid discs (especially those used for competition). Non-competition plates often have variable diameters and widths, such as on the adjustable dumbbells pictured right, with heavier plates generally being larger in diameter, thickness, or both. Weight plates are typically round, although 12-sided and other polygonal varieties ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knurling
Knurling is a manufacturing process, typically conducted on a lathe, whereby a pattern of straight, angled or crossed lines is rolled into the material. Etymology The terms ''knurl'' and ''knurled'' are from an earlier ''knur'' ‘knot in wood’ and the diminutive ''-le'', from Middle English ''knaur'' or ''knarre'' ‘knot in wood; twisted rock; crag’. This descends from Old English ''cnearra'' but the vowel in Middle English may have been influenced by Old Norse ''knǫrr'' ‘merchant ship’ which was known as ''cnearr'' in Old English. The modern ''gnarl'' is a back-formation of ''gnarled'' which itself is first attested in Shakespeare’s works and is apparently a variant of ''knurled''. Uses The operation is performed for producing indentations on a part of a workpiece. Knurling allows hands or fingers to get a better grip on the knurled object than would be provided by the originally smooth metal surface. Occasionally, the knurled pattern is a series of straight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pattern
A pattern is a regularity in the world, in human-made design, or in abstract ideas. As such, the elements of a pattern repeat in a predictable manner. A geometric pattern is a kind of pattern formed of geometric shapes and typically repeated like a wallpaper design. Any of the senses may directly observe patterns. Conversely, abstract patterns in science, mathematics, or language may be observable only by analysis. Direct observation in practice means seeing visual patterns, which are widespread in nature and in art. Visual patterns in nature are often chaotic, rarely exactly repeating, and often involve fractals. Natural patterns include spirals, meanders, waves, foams, tilings, cracks, and those created by symmetries of rotation and reflection. Patterns have an underlying mathematical structure; indeed, mathematics can be seen as the search for regularities, and the output of any function is a mathematical pattern. Similarly in the sciences, theories explain and predict reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. 9.2 billion tonnes of plastic are estimated to have been made between 1950 and 2017. More than half this plastic has been produced since 2004. In 2020, 400 million tonnes of plastic were produced. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will reach over 1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoprene
Neoprene (also polychloroprene) is a family of synthetic rubbers that are produced by polymerization of chloroprene.Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf Krüger "Rubber, 4. Emulsion Rubbers" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH, Weinheim. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. Neoprene is sold either as solid rubber or in latex form and is used in a wide variety of commercial applications, such as laptop sleeves, orthopaedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet-applied elastomeric membranes or flashings, and automotive fan belts. Production Neoprene is produced by free-radical polymerization of chloroprene. In commercial production, this polymer is prepared by free radical emulsion polymerization. Polymerization is initiated using potassium persulfate. Bifunctional nucleophiles, metal oxides (e.g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, and Indonesia are three of 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 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 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 wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cast Iron
Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impurities which allow cracks to pass straight through, grey cast iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material breaks, and ductile cast iron has spherical graphite "nodules" which stop the crack from further progressing. Carbon (C), ranging from 1.8 to 4 wt%, and silicon (Si), 1–3 wt%, are the main alloying elements of cast iron. Iron alloys with lower carbon content are known as steel. Cast iron tends to be brittle, except for malleable cast irons. With its relatively low melting point, good fluidity, castability, excellent machinability, resistance to deformation and wear resistance, cast irons have become an engineering material with a wide range of applications and are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wrist Weights
Weighted clothing are garments that have heavy materials incorporated into them, to add weight to various parts of the body, usually as part of resistance training. The effect is achieved through attaching weighted pieces to the body (or to other garments) which leave the hands free to grasp objects. Unlike with held weights or machines, weighted clothing can leave users more able to do a variety of movements and manual labour. In some cases certain weighted clothing can be worn under normal clothing, to disguise its use to allow exercise in casual environments. The use of weighted clothing is a form of resistance training, generally a kind of weight training. In addition to the greater effect of gravity on the person, it also adds resistance during ballistic movements, due to more force needed to overcome the inertia of heavier masses, as well as a greater momentum that needs deceleration at the end of the movement to avoid injury. The method may increase muscle mass or lose weig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
