1.
Hammer
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A hammer is a tool or device that delivers a blow to an object. Most hammers are hand tools used to drive nails, fit parts, forge metal, hammers vary in shape, size, and structure, depending on their purposes. Hammers are basic tools in many trades, the usual features are a head and a handle. Although most hammers are hand tools, powered versions exist, they are known as powered hammers, types of power hammer include steam hammers and trip hammers, often for heavier uses, such as forging. Some hammers have other names, such as sledgehammer, mallet, the term hammer also applies to devices that deliver blows, such as the hammer of a firearm or the hammer of a piano or the hammer ice scraper. The use of simple hammers dates to about 2,600,000 BCE when various shaped stones were used to strike wood, bone, or other stones to break them apart and shape them. Stones attached to sticks with strips of leather or animal sinew were being used as hammers with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age. The hammers archeological record shows that it may be the oldest tool for which evidence exists of its early existence. A traditional hand-held hammer consists of a head and a handle, fastened together by means of a special wedge made for the purpose, or by glue. This two-piece design is used, to combine a dense metallic striking head with a non-metallic mechanical-shock-absorbing handle. If wood is used for the handle, it is often hickory or ash, rigid fiberglass resin may be used for the handle, this material does not absorb water or decay, but does not dissipate shock as well as wood. A loose hammer head is hazardous because it can fly off the handle when in use. Wooden handles can often be replaced when worn or damaged, specialized kits are available covering a range of sizes and designs. Some hammers are one-piece designs made primarily of a single material, a one-piece metallic hammer may optionally have its handle coated or wrapped in a resilient material such as rubber, for improved grip and reduced user fatigue. The hammer head may be surfaced with a variety of materials, including brass, bronze, wood, plastic, rubber, some hammers have interchangeable striking surfaces, which can be selected as needed or replaced when worn out. A large hammer-like tool is a maul, a wood- or rubber-headed hammer is a mallet, the essential part of a hammer is the head, a compact solid mass that is able to deliver a blow to the intended target without itself deforming. The impacting surface of the tool is usually flat or slightly rounded, some upholstery hammers have a magnetized face, to pick up tacks. In the hatchet, the hammer head may be secondary to the cutting edge of the tool
2.
Sledgehammer
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A sledgehammer is a tool with a large, flat, often metal head, attached to a lever. The size of its head allows a sledgehammer to apply more force than other hammers of similar size, along with the mallet, it shares the ability to distribute force over a wide area. This is in contrast to other types of hammers, which concentrate force in a small area. The word sledgehammer is derived from the Anglo Saxon slægan, which, in its first sense, the English words slag, slay, and slog are cognates. The handle can range from 50 centimetres to a full 1 metre long, depending on the mass of the head, the head mass is usually 1 to 3 kilograms. Modern heavy duty sledgehammers come with 10 to 20 pounds heads, sledgehammers usually require two hands and a swinging motion involving the entire torso, in contrast to smaller hammers used for driving in nails. The combination of a long swinging range, and heavy head, sledgehammers are often used in destruction work, for breaking through drywall or masonry walls. Sledgehammers are seldom used in mining operations, particularly hand steel. Sledgehammers are also used when substantial force is necessary to dislodge a trapped object, another common use is for driving fence posts into the ground. Sledgehammers are used by forces in raids on property to gain entry by force. They were and still are used by blacksmiths to shape heavy sections of iron. The British SAS counter terrorist team used sledgehammers to gain access to rooms during the 1980 Iranian Embassy Siege, however, today they use a tool called a dynamic hammer. Another iconic use of sledgehammers is for driving railroad spikes into wooden sleepers during rail construction, when the two ends of the Union Pacific railroad were joined at Promontory, Utah, Leland Stanford hammered a golden spike into a tie with a silver hammer. Sledges used to drive spikes for rails had curved heads that came down to a beak that was only one inch across. The shape meant that drivers needed to be accurate, and spot where the hit was often not much larger than a dime. Anything larger would hit the plate or the tie, the curved head kept the handle away from the rail, as the spikes were driven with the rail between the spike and the driver. These are often called spike mauls, a drilling hammer, club hammer, lump hammer, crack hammer, mini-sledge or thor hammer is a small sledgehammer whose relatively light weight and short handle allow single-handed use. It is useful for demolition work, driving masonry nails
3.
Aluminium
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Aluminium or aluminum is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal, Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is combined in over 270 different minerals. The chief ore of aluminium is bauxite, Aluminium is remarkable for the metals low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the industry and important in transportation and structures, such as building facades. The oxides and sulfates are the most useful compounds of aluminium, despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals. Because of these salts abundance, the potential for a role for them is of continuing interest. Aluminium is a soft, durable, lightweight, ductile. It is nonmagnetic and does not easily ignite, a fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation. The yield strength of aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has about one-third the density and stiffness of steel and it is easily machined, cast, drawn and extruded. Aluminium atoms are arranged in a cubic structure. Aluminium has an energy of approximately 200 mJ/m2. Aluminium is a thermal and electrical conductor, having 59% the conductivity of copper. Aluminium is capable of superconductivity, with a critical temperature of 1.2 kelvin. Aluminium is the most common material for the fabrication of superconducting qubits, the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts, particularly in the presence of dissimilar metals. In highly acidic solutions, aluminium reacts with water to form hydrogen, primarily because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium
4.
Rubber
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Natural rubber, also called India rubber or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds, plus water. Malaysia and Indonesia are two of the leading rubber producers, forms 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 tree or others. The latex is a sticky, milky colloid drawn off by making incisions in the bark, the latex then is refined into rubber 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 marketing. 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 is extremely waterproof. The major commercial source of rubber latex is the Pará rubber tree. 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 source of rubber, came from vines in the genus Landolphia. These cannot be cultivated, and the drive to collect latex from wild plants was responsible for many of the atrocities committed under the Congo Free State. The latex exhibits the quality as the natural rubber from rubber trees. In the wild types of dandelion, latex content is low, in Nazi Germany, research projects tried to use dandelions as a base for rubber production, but failed. 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 processing to produce anything like usable rubber. Some produce other desirable materials, for example gutta-percha and chicle from Manilkara species, the term gum rubber 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 cultures of Mesoamerica. The earliest archeological evidence of the use of latex from the Hevea tree comes the Olmec culture. The Pará rubber tree is indigenous to South America, charles Marie de La Condamine is credited with introducing samples of rubber to the Académie Royale des Sciences of France in 1736
5.
Wood
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Wood is a porous and fibrous structural tissue found in the stems and roots of trees, and other woody plants. It is a material, a natural composite of cellulose fibers which are strong in tension embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, in a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots, Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber. In 2005, the stock of forests worldwide was about 434 billion cubic meters. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy, in 1991 approximately 3.5 billion cubic meters of wood were harvested. Dominant uses were for furniture and building construction, a 2011 discovery in the Canadian province of New Brunswick discovered the earliest known plants to have grown wood, approximately 395 to 400 million years ago. Wood can be dated by carbon dating and in species by dendrochronology to make inferences about when a wooden object was created. People have used wood for millennia for many purposes, primarily as a fuel or as a material for making houses, tools, weapons, furniture, packaging, artworks. Constructions using wood date back ten thousand years, buildings like the European Neolithic long house were made primarily of wood. Recent use of wood has changed by the addition of steel. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the climate at that time. This process is known as growth, it is the result of cell division in the vascular cambium, a lateral meristem. These cells then go on to form thickened secondary cell walls, composed mainly of cellulose, hemicellulose, if the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are likely to be indistinct or absent, if the bark of the tree has been removed in a particular area, the rings will likely be deformed as the plant overgrows the scar. It is usually lighter in color than that near the portion of the ring. The outer portion formed later in the season is known as the latewood or summerwood. However, there are differences, depending on the kind of wood
6.
Splitting maul
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A splitting maul also known as a block buster, block splitter, sledge axe, or go-devil is a heavy, long-handled axe used for splitting a piece of wood along its grain. One side of its head is like a sledgehammer, and the side is like an axe. Wedged mauls A typical maul for wood splitting will have a head weighing in region of 4 kg, traditionally, mauls have a wedge-shaped head, but some modern versions have conical heads or swiveling sub-wedges. The original maul resembles an axe but with a broader head, for splitting wood, this tool is much better than a typical axe. The weight of it is advantageous and due to its width. The wedge section of a maul head must be convex to avoid jamming. Unlike an axe, maul handles are normally straight and closer to round than the elongated oval axe handles tend to be, a mauls handle, unlike an axe, is intentionally used for levering as well as swinging. The handles are made from hickory, though synthetic fibreglass handles have become common. Plastic handles are more difficult to break and their heads are less likely to work free with the levering action of a maul. In the early 1970s a triangular design with an unbreakable metal handle was introduced called the Monster Maul. Separate wedges Splitting may also be done with a separate wedge, as this allows several wedges to be used together, it permits larger logs to be split. To avoid mushrooming the head of the wedge, they are driven with a wooden mallet rather than an iron hammer. In parts of England the word maul denotes this tool with a heavy wooden head. It is also known as a beetle, there is a well known pub on the River Thames at Moulsford called the Beetle, powered log splitters Hydraulic log splitters are commonly used today. They can be horizontal or vertical. The maul is most commonly struck onto a section of log. Most cut sections can be split in a single downward chop of the maul, mauls regularly become stuck in the log for several reasons, such as the wood not being struck with adequate force, the wood containing hidden knots, or the length of wood being too long. Unlike an axe, mauls are effective longer after the edge dulls, as the mechanism is that of a wedge pushed through along the wood grain
7.
Drywall
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Drywall is a panel made of calcium sulfate dihydrate with or without additives and normally pressed between a facer and a backer. It is used to make walls and ceilings. The plaster is mixed with fibre, plasticizer, foaming agent, and various additives that can decrease mildew, increase fire resistance, drywall construction became prevalent in North America as a speedier alternative to traditional lath and plaster. The first plasterboard plant in the UK was opened in 1888 in Rochester, Sackett Board was invented in 1894 by Augustine Sackett and Fred Kane. It was made by layering plaster within four plies of wool felt paper, sheets were 36 ×36 × 1/4 thick with open edges. Gypsum board evolved between 1910 and 1930 beginning with wrapped board edges and elimination of the two layers of felt paper in favor of paper-based facings. In 1910 United States Gypsum Corporation bought Sackett Plaster Board Company, providing efficiency of installation, it was developed additionally as a measure of fire resistance. Later air entrainment technology made boards lighter and less brittle, then joint treatment materials, rock lath was an early substrate for plaster. As it evolved, it was faced with paper impregnated with gypsum crystals that bonded with the applied facing layer of plaster, a wallboard panel consists of a layer of gypsum plaster sandwiched between two layers of paper. The raw gypsum, CaSO4·2 H2O, is heated to drive off the water then slightly rehydrated to produce the hemihydrate of calcium sulfate, the board is then formed by sandwiching a core of the wet mixture between two sheets of heavy paper or fibreglass mats. When the core sets it is dried in a large drying chamber. Drying chambers typically use natural gas today, to dry 1 MSF of wallboard, between 1,750,000 and 2,490,000 BTU is required. Organic dispersants/plasticisers are used so the slurry will flow during manufacture, coal-fired power stations include devices called scrubbers to remove sulphur from their exhaust emissions. The sulphur is absorbed by powdered limestone in a process called flue-gas desulphurization and this is commonly used in drywall construction in the United States and elsewhere. Drywall panels in the United States are manufactured in 48-inch, 54-inch and 96-inch wide panels in varying lengths to suit the application, lengths up to 12-feet are commonly available, though the most common length is 8-feet. Common panel thicknesses are 1⁄2-inch and 5⁄8-inch, with panels also available in 1⁄4-inch, 3⁄8-inch, 3/4-inch and 1-inch for specific applications, in Europe plasterboard is manufactured in metric sizes, with the common sizes being corollaries of old imperial sizes. Most plasterboard is made in 120 cm-wide sheets, though 90 cm and 60 cm wide sheets are also made,120 cm wide plasterboard is most commonly made in 240 cm lengths, though 250,260,270,280,300 cm and even longer are commonly available. Thicknesses of plasterboard available are 9.5 mm to 25 mm, however four side chamfered drywall is not currently offered by major UK manufacturers for general use
8.
Upholstery
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Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word upholstery comes from the Middle English word upholder, which referred to a tradesman who held up his goods, a person who works with upholstery is called an upholsterer, an apprentice upholsterer is sometimes called an outsider or trimmer. Traditional upholstery uses materials like coil springs, animal hair, coir, straw and hay, hessians, linen scrims, wadding, etc. and is done by hand, in contrast, modern upholsterers employ synthetic materials like dacron and vinyl, serpentine springs, and so on. Upholder is a term used for upholsterer, but it appears to have a connotation of repairing furniture rather than creating new upholstered pieces from scratch. In 18th-century London, upholders frequently served as interior decorators responsible for all aspects of a rooms decor and these individuals were members of the Worshipful Company of Upholders, whose traditional role, prior to the 18th century, was to provide upholstery and textiles and the fittings for funerals. In the great London furniture-making partnerships of the 18th century, a cabinet-maker usually paired with an upholder, Vile and Cobb, Ince and Mayhew, Chippendale and Rannie or Haig. In the USA, Grand Rapids, Michigan and Hickory, North Carolina are centers for furniture manufacture along with Long Eaton, Nottinghamshire and these craftsmen continue to create or recreate many antique and modern pieces of furniture. Furniture reupholstery continues to thrive in the UK with several businesses small, traditional upholstery is a craft which evolved over centuries for padding and covering chairs, seats and sofas, before the development of sewing machines synthetic fabrics and plastic foam. In the Middle Ages, domestic interiors were becoming more comfortable, by the beginning of the 17th century chair seats were being padded, but this form of upholstery was still fairly basic. The stuffing was heaped on a platform and held in place with a decorative top fabric. This produced a dome shape sloping towards the seat. Only towards the end of the 17th century did upholsterers start to develop the techniques that would distribute, curled horsehair was being used more consistently for stuffing that was easier to hold in place with stitches in twine that were developed from saddlery techniques. Thus layers of stuffing could be distributed evenly and secured to stay in place, on a basic level, squab cushions were made more stable by using tufting ties. Stuffed edge rolls appeared on seat fronts providing support for cushions to be retained, what we now think of as classic upholstery shapes and techniques flourished in the 18th century. Frames of elegant line and proportion were sympathetically matched by expertly executed upholstery, by now, the upholsterers technical knowledge meant that stuffings could be controlled along upright and sloping lines, giving new levels of comfort and a simply stated elegance. Later in the century, the border was replaced by a piece of linen or scrim taken over the stuffed seat. At the same time the blind stitch and top-stitching combination had evolved. In the Victorian era, fashions of opulence and comfort gave rise to excesses of stuffing and padding, mass production techniques made upholstered furniture available in large quantity to all sections of society
9.
Carpentry
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Carpentry in the United States is almost always done by men. With 98. 5% of carpenters being male, it was the fourth most male-dominated occupation in the country in 1999, Carpenters are usually the first tradesmen on a job and the last to leave. Carpenters normally framed post-and-beam buildings until the end of the 19th century and it is also common that the skill can be learned by gaining work experience other than a formal training program, which may be the case in many places. The word carpenter is the English rendering of the Old French word carpentier which is derived from the Latin carpentrius, the Middle English and Scots word was wright, which could be used in compound forms such as wheelwright or boatwright. An easy way to envisage this is that first fix work is all that is done before plastering takes place, second fix is done after plastering takes place. Second fix work, the construction of such as skirting boards, architraves. Carpentry is also used to construct the formwork into which concrete is poured during the building of such as roads. In the UK, the skill of making timber formwork for poured, or in situ, although the. work of a carpenter and joiner are often combined. Joiner is less common than the finish carpenter or cabinetmaker. The terms housewright and barnwright were used historically, now used by carpenters who work using traditional methods. Someone who builds custom concrete formwork is a form carpenter, wood is one of mankinds oldest building materials. The ability to shape wood improved with technological advances from the age to the bronze age to the iron age. The oldest surviving, complete text is Vitruvius ten books collectively titled De architectura which discusses some carpentry. By the 16th century sawmills were coming into use in Europe, the founding of America was partly based on a desire to extract resources from the new continent including wood for use in ships and buildings in Europe. In the 18th century part of the Industrial Revolution was the invention of the steam engine and these technologies combined with the invention of the circular saw led to the development of balloon framing which was the beginning of the decline of traditional timber framing. The 19th century saw the development of engineering and distribution which allowed the development of hand-held power tools, wire nails. In the 20th century portland cement came into use and concrete foundations allowed carpenters to do away with heavy timber sills. Also, drywall came into common use replacing lime plaster on wooden lath, plywood, engineered lumber and chemically treated lumber also came into use
10.
Dowel
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A dowel is a solid cylindrical rod, usually made from wood, plastic, or metal. In its original manufactured form, a dowel is called a dowel rod, dowel rods are often cut into short lengths called dowel pins. Dowels are employed in numerous, diverse applications including axles in toys, detents, structural reinforcements in cabinet making, to make a dowel, a piece of wood is split or whittled to a size slightly bigger than desired and then driven through the hole in the dowel plate. The sharp edges of the hole shear off the excess wood, a second approach to cutting dowels is to rotate a piece of oversized stock past a fixed knife, or alternatively, to rotate the knife around the stock. Machines based on this principle emerged in the 19th century, frequently, these are small bench-mounted tools. For modest manufacturing volumes, wood dowels are typically manufactured on industrial dowel machines based on the principles as the rotary cutters described above. Such machines may employ interchangeable cutting heads of varying diameters, thus enabling the machines to be changed to manufacture different dowel diameters. Typically, the mechanism is open-ended, with material guides at the machines entry, since the 19th century, some of these dowel machines have had power feed mechanisms to move the stock past the cutting mechanism. High-volume dowel manufacturing is done on a shaper, which simultaneously forms multiple dowels from a single piece of rectangular stock. These machines employ two wide, rotating cutting heads, one above the stock and one below it, the heads have nearly identical cutting profiles so that each will form an array of adjoined, side-by-side half dowels. The wooden dowel rod used in woodworking applications is commonly cut into dowel pins, some woodworkers make their own dowel pins, while others purchase dowel pins precut to the required length and diameter. When dowels are glued into blind holes, a common case in dowel-based joinery, there must be a path for air. If no provision is made to relieve the pressure of air and glue. An old solution to this problem is to plane a flat on the side of the dowel, some dowel pins are Fluted with multiple parallel grooves along their length to serve the same purpose. When two pieces of wood are to be joined by dowels embedded in holes, there are numerous methods for aligning the holes. Dowel centers are simple and inexpensive tools for aligning opposing blind holes, various commercial systems, such as Dowelmax, have been devised to solve this problem. Alternative joinery methods may be used in place of conventional dowel pins, such as Miller dowels, biscuit joiners, spline joints, and proprietary tools such as the Domino jointer. The word dowel was used in Middle English, it appears in Wycliffes Bible translation in a list of the parts of a wheel. and the spokis, cognates with other Germanic languages suggest that the word is much older
11.
Chisel
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The handle and blade of some types of chisel are made of metal or of wood with a sharp edge in it. Chiselling use involves forcing the blade into some material to cut it, the driving force may be applied by pushing by hand, or by using a mallet or hammer. In industrial use, a ram or falling weight drives a chisel into the material. A gouge, one type of chisel, serves - particularly in woodworking, woodturning, gouges most frequently produce concave surfaces. A gouge typically has a U-shaped cross-section, chisel comes from the Old French cisel, modern ciseau, Late Latin cisellum, a cutting tool, from caedere, to cut. Chisels have a variety of uses. Many types of chisel have been devised, each suited to its intended use. Different types of chisel may be constructed differently, in terms of blade width or length, as well as shape. They may have a wooden or plastic handle attached using a tang or socket, woodworking chisels range from small hand tools for tiny details, to large chisels used to remove big sections of wood, in roughing out the shape of a pattern or design. Typically, in woodcarving, one starts with a larger tool, one of the largest types of chisel is the slick, used in timber frame construction and wooden shipbuilding. There are many types of woodworking chisels used for specific purposes, such as, Butt chisel, short chisel with beveled sides and straight edge for creating joints. Carving chisels, used for designs and sculpting, cutting edges are many, such as gouge, skew, parting, straight, paring. Corner chisel, resembles a punch and has an L-shaped cutting edge, cleans out square holes, mortises and corners with 90 degree angles. Bevel edge chisel, can get into acute angles with its bevelled edges, flooring chisel, cuts and lifts flooring materials for removal and repair, ideal for tongue-and-groove flooring. Framing chisel, usually used with mallet, similar to a chisel, except it has a longer. Slick, a large chisel driven by pressure, never struck. Mortise chisel, thick, rigid blade with cutting edge and deep, slightly tapered sides to make mortises. Paring chisel, has a long blade ideal for cleaning grooves, skew chisel, has a 60 degree cutting angle and is used for trimming and finishing
12.
Cricket bat
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A cricket bat is a specialised piece of equipment used by batsmen in the sport of cricket to hit the ball, typically consisting of a cane handle attached to a flat-fronted willow-wood blade. The length of the bat may be no more than 38 inches and its use is first mentioned in 1624. The blade of a bat is a wooden block that is generally flat on the striking face. The bat is made from willow wood, specifically from a variety of White Willow called Cricket Bat Willow, treated with raw linseed oil. This variety of willow is used as it is tough and shock-resistant, not being significantly dented nor splintering on the impact of a cricket ball at high speed. The face of the bat is often covered with a film by the user. The blade is connected to a long cane handle, similar to that of a mid-20th-century tennis racquet. The handle is covered with a rubber grip. Bats incorporate a spring design where the handle meets the blade. Spliced handles had been used before this but tended to break at the corner of the join, the taper provides a more gradual transfer of load from the bats blade to the handle and avoids this problem. The edges of the blade closest to the handle are known as the shoulders of the bat, bats were not always this shape. Before the 18th century bats tended to be shaped similarly to a modern hockey sticks and this may well have been a legacy of the games reputed origins. Although the first forms of cricket are obscure, it may be that the game was first played using shepherds crooks, the bat generally recognised as the oldest bat still in existence is dated 1729 and is on display in the Sandham Room at The Oval in London. Knocking-in involves striking the surface with an old cricket ball or a special mallet and this compacts the soft fibres within the bat and reduces the risk of the bat snapping. The bat may also need raw linseed oil, which fills in the gaps between the fibres. Law 6 of the Laws of Cricket, as the rules of the game are known, state that the length of the bat may be no more than 38 in, bats typically weigh from 2 lb 7 oz to 3 lb though there is no standard. Appendix E of the Laws of Cricket set out more precise specifications and this rule was introduced following the Monster Bat Incident of 1771. Bats are available in a range of sizes, with some manufacturers offering unique variations, commonly found are childrens sizes 0 to 6, youth size Harrow and adult sizes
13.
Copper
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Copper is a chemical element with symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with high thermal and electrical conductivity. A freshly exposed surface of copper has a reddish-orange color. Copper is one of the few metals that occur in nature in directly usable metallic form as opposed to needing extraction from an ore and this led to very early human use, from c.8000 BC. Copper used in buildings, usually for roofing, oxidizes to form a green verdigris, Copper is sometimes used in decorative art, both in its elemental metal form and in compounds as pigments. Copper compounds are used as agents, fungicides, and wood preservatives. Copper is essential to all living organisms as a trace dietary mineral because it is a key constituent of the enzyme complex cytochrome c oxidase. In molluscs and crustaceans, copper is a constituent of the blood pigment hemocyanin, replaced by the hemoglobin in fish. In humans, copper is found mainly in the liver, muscle, the adult body contains between 1.4 and 2.1 mg of copper per kilogram of body weight. The filled d-shells in these elements contribute little to interatomic interactions, unlike metals with incomplete d-shells, metallic bonds in copper are lacking a covalent character and are relatively weak. This observation explains the low hardness and high ductility of single crystals of copper, at the macroscopic scale, introduction of extended defects to the crystal lattice, such as grain boundaries, hinders flow of the material under applied stress, thereby increasing its hardness. For this reason, copper is supplied in a fine-grained polycrystalline form. The softness of copper partly explains its high conductivity and high thermal conductivity. The maximum permissible current density of copper in open air is approximately 3. 1×106 A/m2 of cross-sectional area, Copper is one of a few metallic elements with a natural color other than gray or silver. Pure copper is orange-red and acquires a reddish tarnish when exposed to air, as with other metals, if copper is put in contact with another metal, galvanic corrosion will occur. A green layer of verdigris can often be seen on old structures, such as the roofing of many older buildings. Copper tarnishes when exposed to sulfur compounds, with which it reacts to form various copper sulfides. There are 29 isotopes of copper, 63Cu and 65Cu are stable, with 63Cu comprising approximately 69% of naturally occurring copper, both have a spin of 3⁄2
14.
Brass
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Brass is a metal alloy made of copper and zinc, the proportions of zinc and copper can be varied to create a range of brasses with varying properties. It is an alloy, atoms of the two constituents may replace each other within the same crystal structure. By comparison, bronze is principally an alloy of copper and tin, however, bronze and brass may also include small proportions of a range of other elements including arsenic, phosphorus, aluminium, manganese, and silicon. The term is applied to a variety of brasses. Modern practice in museums and archaeology increasingly avoids both terms for objects in favour of the all-embracing copper alloy. It is also used in zippers, Brass is often used in situations in which it is important that sparks not be struck, such as in fittings and tools used near flammable or explosive materials. Brass has higher malleability than bronze or zinc, the relatively low melting point of brass and its flow characteristics make it a relatively easy material to cast. By varying the proportions of copper and zinc, the properties of the brass can be changed, allowing hard, the density of brass is 8.4 to 8.73 grams per cubic centimetre. Today, almost 90% of all alloys are recycled. Because brass is not ferromagnetic, it can be separated from ferrous scrap by passing the scrap near a powerful magnet, Brass scrap is collected and transported to the foundry where it is melted and recast into billets. Billets are heated and extruded into the form and size. The general softness of brass means that it can often be machined without the use of cutting fluid, aluminium makes brass stronger and more corrosion-resistant. Aluminium also causes a highly beneficial hard layer of oxide to be formed on the surface that is thin, transparent. Tin has an effect and finds its use especially in seawater applications. Combinations of iron, aluminium, silicon and manganese make brass wear and tear resistant, to enhance the machinability of brass, lead is often added in concentrations of around 2%. Since lead has a melting point than the other constituents of the brass. The pattern the globules form on the surface of the brass increases the available surface area which in turn affects the degree of leaching. In addition, cutting operations can smear the lead globules over the surface and these effects can lead to significant lead leaching from brasses of comparatively low lead content
15.
Lead
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Lead is a chemical element with atomic number 82 and symbol Pb. When freshly cut, it is bluish-white, it tarnishes to a dull gray upon exposure to air and it is a soft, malleable, and heavy metal with a density exceeding that of most common materials. Lead has the second-highest atomic number of the stable elements. Lead is a relatively unreactive post-transition metal and its weak metallic character is illustrated by its amphoteric nature and tendency to form covalent bonds. Compounds of lead are found in the +2 oxidation state. Exceptions are mostly limited to organolead compounds, like the lighter members of the group, lead exhibits a tendency to bond to itself, it can form chains, rings, and polyhedral structures. Lead is easily extracted from its ores and was known to people in Western Asia. A principal ore of lead, galena, often bears silver, Lead production declined after the fall of Rome and did not reach comparable levels again until the Industrial Revolution. Nowadays, global production of lead is about ten million tonnes annually, Lead has several properties that make it useful, high density, low melting point, ductility, and relative inertness to oxidation. In the late 19th century, lead was recognized as poisonous, Lead is a neurotoxin that accumulates in soft tissues and bones, damaging the nervous system and causing brain disorders and, in mammals, blood disorders. A lead atom has 82 electrons, arranged in a configuration of 4f145d106s26p2. The combined first and second ionization energies—the total energy required to remove the two 6p electrons—is close to that of tin, leads upper neighbor in group 14. This is unusual since ionization energies generally fall going down a group as an elements outer electrons become more distant from the nucleus, the similarity is caused by the lanthanide contraction—the decrease in element radii from lanthanum to lutetium, and the relatively small radii of the elements after hafnium. The contraction is due to shielding of the nucleus by the lanthanide 4f electrons. The combined first four ionization energies of lead exceed those of tin, for this reason lead, unlike tin, mostly forms compounds in which it has an oxidation state of +2, rather than +4. Relativistic effects, which become particularly prominent at the bottom of the periodic table, as a result, the 6s electrons of lead become reluctant to participate in bonding, a phenomenon called the inert pair effect. A related outcome is that the distance between nearest atoms in crystalline lead is unusually long, the lighter group 14 elements form stable or metastable allotropes having the tetrahedrally coordinated and covalently bonded diamond cubic structure. The energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp3 orbitals
16.
Spark (fire)
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A spark is an incandescent particle. Such sparks may be produced by pyrotechnics, by metalworking or as a by-product of fires, in pyrotechnics, iron filings and metal alloys such as magnalium may be used to create sparks. The quantity and style of sparks produced depends on the composition and pyrophoricity of the metal, in the case of iron, the presence of carbon is required, as in carbon steel — about 0. 7% is best for large sparks. The carbon burns explosively in the hot iron and this produces pretty, the duration of the existence of a spark is determined by the initial size of the particle, with a larger size leading to a longer-lasting spark. Metals with low thermal conductivity are especially good at producing sparks, titanium and zirconium are especially good in this respect and so are now used in fireworks. Copper, on the hand, has a high conductivity. For this reason, alloys of copper such as beryllium bronze are used to make safety tools which will not spark so easily, robert Hooke studied the sparks created by striking a piece of flint and steel together. He found that the sparks were usually particles of the steel which had become red hot and these sparks can be used to ignite tinder and so start a fire. In colonial America, flint and steel were used to light fires when easier methods failed, scorched linen was commonly used as tinder to catch the spark and start the fire but producing a good spark could take much time. A spinning steel wheel provided a stream of sparks when it engaged the flint. In a modern lighter or firesteel, iron is mixed with cerium and this readily produces sparks when scraped and burns hotter than steel would. This higher temperature is needed to ignite the vapour of the lighter fluid, molten metal sparks can be created when metal is heated by processes such as Bessemer conversion of iron to steel or arc welding. Arc welding uses a low voltage and high current electric arc between an electrode and the material to melt the metals at the welding point, which often creates sparks. To reduce the risk of burns, welders wear heavy leather gloves and long sleeve jackets to avoid exposure to heat, flames. In spot welding, metal surfaces that are held in contact are joined by the heat resistance to electric current flow. It is common for a spray of sparks in the form of metal droplets to be ejected from the parts being joined. Or the resistance heating of spot welding, fires may produce sparks as updrafts carry particles of the burning fuel aloft. This was a problem with steam locomotives as the sparks might set fire to the adjacent landscape or even to the train itself
17.
Tenderizing
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Tenderness is a quality of meat gauging how easily it is chewed or cut. Tenderness is a quality, as tender meat is softer, easier to chew. Conversely, tender pieces of meat generally acquire higher price than harder ones, the tenderness depends on a number of factors including the meat grain, the amount of connective tissue, and the amount of fat. Tenderness can be increased by a number of processing techniques, generally referred to as tenderizing or tenderization, Tenderness is perhaps the most important of all factors impacting meat eating quality, with others being flavor, juiciness, and succulence. Tenderness is a quality complex to obtain and gauge, and it depends on a number of factors, on the basic level, meat grain, the amount and composition of connective tissue, and the amount of fat. Meat with the fat content, deposited within the steak to create an appearance, has always been regarded as more tender than steaks where the fat is in a separate layer. Cooking causes melting of the fat, spreading it throughout the meat, the meat industry strives to produce meat with standardized and guaranteed tenderness, since these characteristics are sought for by the consumers. Techniques for breaking down collagens in meat to make it more palatable, there are a number of ways to tenderize meat, Mechanical tenderization, such as pounding, or piercing. The tenderization that occurs through cooking, such as braising, marinating the meat with vinegar, wine, lemon juice, buttermilk or yogurt. Brining the meat in a salt solution, dry aging of meat at 0 to 2 °C. Efforts have been made since at least 1970 to use explosives to tenderize meat, food portal Improving Meat Tenderness by John Marchello and Ron Allen PPT
18.
Cube steak
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Cube steak is a cut of beef, usually top round or top sirloin, tenderized by fierce pounding with a meat tenderizer, or use of an electric tenderizer. The name refers to the shape of the left by that process. This is the most common cut of meat used for the American dish chicken fried steak, in Canada as well as in some parts of the United States, cube steak may be called a minute steak, because it can be cooked quickly. The term minute steak is used in the United Kingdom
19.
Rawhide (textile)
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Rawhide is a hide or animal skin that has not been exposed to tanning. It is similar to parchment, much lighter in color than leather made by traditional vegetable tanning, the skin from buffalo, deer, elk or cattle from which most rawhide originates is prepared by removing all fur, meat and fat. The hide is then stretched over a frame before being dried. The resulting material is hard and translucent and it can be shaped by rewetting and forming before being allowed to thoroughly re-dry. It can be rendered more pliable by working, i. e. bending repeatedly in multiple directions, often by rubbing it over a post and it may also be oiled or greased for a degree of waterproofing. It is often used for such as whips, drumheads or lampshades. It is thought to be more durable than leather, especially in items suffering abrasion during use and it can also be used as a backing on a wooden bow. Such a backing prevents the bow from breaking by taking a share of the tension stress, bows made from weaker woods such as birch or cherry benefit more from a rawhide backing. Rawhide is more susceptible to water than leather, and it quickly softens, rawhide laces often sold for boots or baseball gloves are made of normal tanned leather rather than actual rawhide. Rawhide is not pliable when dry and would be unsuitable for that use, traditional gauchos boots are made with horse feet rawhide. Gauchos skin the animal and put the freshly skinned hides on their feet like socks, like ancient Roman cothurnus, the rudimentary boots have no toe box and do not cover the toes completely. As a chew toy for dogs, it is effective when used for training dogs. Wet rawhide has been used by earlier cultures as a means of torture or execution
20.
Leather
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Leather is a durable and flexible material created by tanning animal rawhide and skin, often cattle hide. It can be produced at manufacturing scales ranging from cottage industry to heavy industry, people use leather to make various goods—including clothing, bookbinding, leather wallpaper, and as a furniture covering. It is produced in a variety of types and styles. Several tanning processes transform hides and skins into leather, Chrome-tanned leather, invented in 1858, is tanned using chromium sulfate and it is more supple and pliable than vegetable-tanned leather and does not discolor or lose shape as drastically in water as vegetable-tanned. It is also known as wet-blue for its color derived from the chromium, more exotic colors are possible when using chrome tanning. The chrome tanning method usually only takes a day to finish, and it is reported that chrome-tanned leather adds up to 80% of the global leather supply. Vegetable-tanned leather is tanned using tannins and other found in different vegetable matter, such as tree bark prepared in bark mills, wood, leaves, fruits. It is supple and brown in color, with the exact shade depending on the mix of chemicals and it is the only form of leather suitable for use in leather carving or stamping. Vegetable-tanned leather is not stable in water, it tends to discolor, so if left to soak and then dried it shrinks, in hot water, it shrinks drastically and partly congeals—becoming rigid, and eventually brittle. Boiled leather is an example of this, where the leather has been hardened by being immersed in hot water, historically, it was occasionally used as armour after hardening, and it has also been used for book binding. Aldehyde-tanned leather is tanned using glutaraldehyde or oxazolidine compounds and this is the leather that most tanners refer to as wet-white leather due to its pale cream or white color. It is the type of chrome-free leather, often seen in shoes for infants. Formaldehyde tanning is another aldehyde tanning method, brain-tanned leathers fall into this category, and are exceptionally water absorbent. Brain tanned leathers are made by a process that uses emulsified oils, often those of animal brains such as deer, cattle. They are known for their softness and washability. Chamois leather also falls into the category of aldehyde tanning, and like brain tanning, produces a porous, chamois leather is made using marine oils that oxidize easily to produce the aldehydes that tan the leather to color it. Rose-tanned leather is a variation of oil tanning and brain tanning. Rose-tanned leather tanned leaves a powerful rose fragrance even years from when it is manufactured and it has been called the most valuable leather on earth, but this is mostly due to the high cost of rose otto and its labor-intensive tanning process
21.
Jewellery
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Jewellery or jewelry consists of small decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, and bracelets. Jewellery may be attached to the body or the clothes, for many centuries metal, often combined with gemstones, has been the normal material for jewellery, but other materials such as shells and other plant materials may be used. It is one of the oldest type of archaeological artefact – with 100, historically, the most widespread influence on jewellery in terms of design and style have come from Asia. Jewellery may be made from a range of materials. Gemstones and similar such as amber and coral, precious metals, beads, and shells have been widely used. In most cultures jewellery can be understood as a symbol, for its material properties, its patterns. Jewellery has been made to nearly every body part, from hairpins to toe rings. The word jewellery itself is derived from the jewel, which was anglicised from the Old French jouel. In British English, Indian English, New Zealand English, Hiberno-English, Australian English, both are used in Canadian English, though jewelry prevails by a two to one margin. Numerous cultures store wedding dowries in the form of jewellery or make jewellery as a means to store or display coins, alternatively, jewellery has been used as a currency or trade good, an example being the use of slave beads. Many items of jewellery, such as brooches and buckles, originated as functional items. Jewellery can also symbolise group membership or status, wearing of amulets and devotional medals to provide protection or ward off evil is common in some cultures. These may take the form of symbols, stones, plants, animals, body parts, in creating jewellery, gemstones, coins, or other precious items are often used, and they are typically set into precious metals. Alloys of nearly every metal known have been encountered in jewellery, bronze, for example, was common in Roman times. Modern fine jewellery usually includes gold, white gold, platinum, palladium, titanium, most contemporary gold jewellery is made of an alloy of gold, the purity of which is stated in karats, indicated by a number followed by the letter K. American gold jewellery must be of at least 10K purity, many whimsical fashions were introduced in the extravagant eighteenth century. Cameos that were used in connection with jewellery were the attractive trinkets along with many of the objects such as brooches, ear-rings. Some of the necklets were made of pieces joined with the gold chains were in and bracelets were also made sometimes to match the necklet
22.
Electric motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this is the conversion of energy into electrical energy and is done by an electric generator. In normal motoring mode, most electric motors operate through the interaction between an electric motors magnetic field and winding currents to generate force within the motor, small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use, the largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, perhaps the first electric motors were simple electrostatic devices created by the Scottish monk Andrew Gordon in the 1740s. The theoretical principle behind production of force by the interactions of an electric current. The conversion of energy into mechanical energy by electromagnetic means was demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet was placed, when a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire. This motor is often demonstrated in experiments, brine substituting for toxic mercury. Though Barlows wheel was a refinement to this Faraday demonstration. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils, after Jedlik solved the technical problems of the continuous rotation with the invention of the commutator, he called his early devices electromagnetic self-rotors. Although they were used only for instructional purposes, in 1828 Jedlik demonstrated the first device to contain the three components of practical DC motors, the stator, rotor and commutator. The device employed no permanent magnets, as the fields of both the stationary and revolving components were produced solely by the currents flowing through their windings. His motor set a record which was improved only four years later in September 1838 by Jacobi himself. His second motor was powerful enough to drive a boat with 14 people across a wide river and it was not until 1839/40 that other developers worldwide managed to build motors of similar and later also of higher performance. The first commutator DC electric motor capable of turning machinery was invented by the British scientist William Sturgeon in 1832, following Sturgeons work, a commutator-type direct-current electric motor made with the intention of commercial use was built by the American inventor Thomas Davenport, which he patented in 1837. The motors ran at up to 600 revolutions per minute, and powered machine tools, due to the high cost of primary battery power, the motors were commercially unsuccessful and Davenport went bankrupt. Several inventors followed Sturgeon in the development of DC motors but all encountered the same battery power cost issues, no electricity distribution had been developed at the time
23.
Plastic
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Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be molded into solid objects. Plastics are typically organic polymers of high mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging, other uses include automobiles, furniture, and toys. In the developing world, the ratios may be different - for example, the worlds first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term plastics. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling, the word plastic is derived from the Greek πλαστικός meaning capable of being shaped or molded, from πλαστός meaning molded. The common word plastic should not be confused with the technical adjective plastic, used for insulating parts in electrical fixtures, paper laminated products, thermally insulation foams. Problems include the probability of moldings naturally being dark colors, One of the most expensive commercial polymers. It forms the basis of artistic and commercial acrylic paints when suspended in water with the use of other agents, polytetrafluoroethylene – Heat-resistant, low-friction coatings, used in things like non-stick surfaces for frying pans, plumbers tape and water slides. It is more known as Teflon. Urea-formaldehyde – One of the aminoplasts and used as an alternative to phenolics. Used as an adhesive and electrical switch housings. Early plastics were bio-derived materials such as egg and blood proteins, in 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines. Treated cattle horns were used as windows for lanterns in the Middle Ages, materials that mimicked the properties of horns were developed by treating milk-proteins with lye. In the 1800s, as industrial chemistry developed during the Industrial Revolution, the development of plastics also accelerated with Charles Goodyears discovery of vulcanization to thermoset materials derived from natural rubber. Parkesine is considered the first man-made plastic, the plastic material was patented by Alexander Parkes, In Birmingham, UK in 1856. It was unveiled at the 1862 Great International Exhibition in London, parkesine won a bronze medal at the 1862 Worlds fair in London
24.
Nylon
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Nylon is a generic designation for a family of synthetic polymers, more specifically aliphatic or semi-aromatic polyamides. They can be melt-processed into fibers, films or shapes, the first example of nylon was produced on February 28,1935, by Wallace Carothers at DuPonts research facility at the DuPont Experimental Station. Nylon polymers have significant commercial applications in fibers, in shapes. Nylon is made of repeating units linked by bonds and is a type of polyamide and is frequently referred to as such. Nylon was the first commercially successful synthetic thermoplastic polymer, commercially, nylon polymer is made by reacting monomers which are either lactams, acid/amines or stoichiometric mixtures of diamines and diacids. Mixtures of these can be polymerized together to make copolymers, Nylon polymers can be mixed with a wide variety of additives to achieve many different property variations. Nylon was invented accidentally by Julian W. Hill, a chemist for DuPont under Wallace Carotherss supervision and it was only given this name at the 1939 New York Worlds Fair. The patents were owned by DuPont, Nylon was intended to be a synthetic replacement for silk and substituted for it in many different products after silk became scarce during World War II. It replaced silk in military applications such as parachutes and flak vests, after initial commercialization of nylon as a fiber, applications in the form of shapes and films were also developed. The main market for nylon shapes now is in auto components, in 1940, John W. Eckelberry of DuPont stated that the letters nyl were arbitrary and the on was copied from the suffixes of other fibers such as cotton and rayon. A later publication by DuPont explained that the name was intended to be No-Run. Since the products were not really run-proof, the vowels were swapped to produce nuron, for clarity in pronunciation, the i was changed to y. Most nylons are made from the reaction of an acid with a diamine or a lactam or amino acid with itself. In the first case, the structure is so-called ABAB similar to polyesters and polyurethanes, in the second case, the repeating unit corresponds to the single monomer. It is difficult to get the proportions exactly correct, and deviations can lead to termination at molecular weights less than a desirable 10,000 daltons. To overcome this problem, a crystalline, solid nylon salt can be formed at room temperature, using an exact 1,1 ratio of the acid, the salt is crystallized to purify it and obtain the desired precise stoichiometry. Heated to 285 °C, the salt reacts to form nylon polymer with the production of water, Wallace Carothers at DuPont patented nylon 66, but overlooked the possibility to use lactams. That synthetic route was developed by Paul Schlack at IG Farben, leading to nylon 6, the peptide bond within the caprolactam is broken with the exposed active groups on each side being incorporated into two new bonds as the monomer becomes part of the polymer backbone
25.
Polycarbonate
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Polycarbonates are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent and they are easily worked, molded, and thermoformed. Because of these properties, polycarbonates find many applications, Polycarbonates do not have a unique resin identification code and are identified as Other,7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A. Polycarbonates received their name because they are polymers containing carbonate groups, a balance of useful features, including temperature resistance, impact resistance and optical properties, positions polycarbonates between commodity plastics and engineering plastics. The main polycarbonate material is produced by the reaction of bisphenol A, the net reaction from the diphenoxide is, Na22CMe2 + COCl2 → 1/n n +2 NaCl In this way, approximately one billion kilograms of polycarbonate is produced annually. Many other diols have been tested in place of bisphenol A, e. g.1, the cyclohexane is used as a comonomer to suppress crystallisation tendency of the BPA-derived product. Tetrabromobisphenol A is used to enhance fire resistance, tetramethylcyclobutanediol has been developed as a replacement for BPA. Although it has high impact-resistance, it has low scratch-resistance, therefore, a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components. The characteristics of polycarbonate compare to those of polymethyl methacrylate, but polycarbonate is stronger, Polycarbonate is highly transparent to visible light, with better light transmission than many kinds of glass. Polycarbonate has a transition temperature of about 147 °C, so it softens gradually above this point. Tools must be held at high temperatures, generally above 80 °C to make strain-free and stress-free products, low molecular mass grades are easier to mold than higher grades, but their strength is lower as a result. The toughest grades have the highest molecular mass, but are more difficult to process. Unlike most thermoplastics, polycarbonate can undergo plastic deformations without cracking or breaking. As a result, it can be processed and formed at room temperature using sheet metal techniques, even for sharp angle bends with a tight radius, heating may not be necessary. This makes it valuable in prototyping applications where transparent or electrically non-conductive parts are needed, pMMA/Acrylic, which is similar in appearance to polycarbonate, is brittle and cannot be bent at room temperature. Due to its chemical properties it is not conducive to laser-cutting, Injection molding into ready articles Polycarbonate may become brittle when exposed to ionizing radiation above 25 kGy. Polycarbonate is mainly used for applications that capitalize on its collective safety features. Being a good insulator and having heat-resistant and flame-retardant properties, it is used in various products associated with electrical
26.
Polystyrene
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Polystyrene /ˌpɒliˈstaɪriːn/ is a synthetic aromatic polymer made from the monomer styrene. Polystyrene can be solid or foamed, general-purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight and it is a rather poor barrier to oxygen and water vapor and has a relatively low melting point. Polystyrene is one of the most widely used plastics, the scale of its production being several million tonnes per year, Polystyrene can be naturally transparent, but can be colored with colorants. Uses include protective packaging, containers, lids, bottles, trays, tumblers, as a thermoplastic polymer, polystyrene is in a solid state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled and this temperature behavior is exploited for extrusion and also for molding and vacuum forming, since it can be cast into molds with fine detail. Polystyrene is very slow to biodegrade and is therefore a focus of controversy among environmentalists, Polystyrene was discovered in 1839 by Eduard Simon, an apothecary from Berlin. From storax, the resin of the American sweetgum tree Liquidambar styraciflua, he distilled an oily substance, several days later, Simon found that the styrol had thickened into a jelly he dubbed styrol oxide because he presumed an oxidation. By 1845 Jamaican-born chemist John Buddle Blyth and German chemist August Wilhelm von Hofmann showed that the transformation of styrol took place in the absence of oxygen. They called the product metastyrol, analysis showed that it was identical to Simons Styroloxyd. In 1866 Marcelin Berthelot correctly identified the formation of metastyrol/Styroloxyd from styrol as a polymerization process, about 80 years later it was realized that heating of styrol starts a chain reaction that produces macromolecules, following the thesis of German organic chemist Hermann Staudinger. This eventually led to the substance receiving its present name, polystyrene, the company I. G. Farben began manufacturing polystyrene in Ludwigshafen, about 1931, hoping it would be a suitable replacement for die-cast zinc in many applications. Success was achieved when they developed a reactor vessel that extruded polystyrene through a tube and cutter. In 1941, Dow Chemical invented a Styrofoam process, before 1949, the chemical engineer Fritz Stastny developed pre-expanded PS beads by incorporating aliphatic hydrocarbons, such as pentane. These beads are the raw material for moulding parts or extruding sheets, BASF and Stastny applied for a patent that was issued in 1949. The moulding process was demonstrated at the Kunststoff Messe 1952 in Düsseldorf, the crystal structure of isotactic polystyrene was reported by Giulio Natta. In 1954, the Koppers Company in Pittsburgh, Pennsylvania, developed expanded polystyrene foam under the trade name Dylite, in 1960, Dart Container, the largest manufacturer of foam cups, shipped their first order. In 1988, the first U. S. ban of general polystyrene foam was enacted in Berkeley, in chemical terms, polystyrene is a long chain hydrocarbon wherein alternating carbon centers are attached to phenyl groups
27.
Timber framing
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Timber framing and post-and-beam construction are methods of building with heavy timbers rather than dimensional lumber such as 2x4s. Traditional timber framing is the method of creating structures using heavy squared-off and it is commonplace in wooden buildings from the 19th century and earlier. The method comes from making out of logs and tree trunks without modern high tech saws to cut lumber from the starting material stock. Since this building method has been used for thousands of years in parts of the world. These styles are categorized by the type of foundation, walls, how and where the beams intersect, the use of curved timbers. Three basic types of frames in English-speaking countries are the box frame, cruck frame. The distinction presented here is the load is carried by the exterior walls. Purlins are also in a timber frame. A cruck is a pair of crooked or curved timbers which form a bent or crossframe, more than 4,000 cruck frame buildings have been recorded in the UK. Several types of frames are used, more information follows in English style below. True cruck or full cruck, blades, straight or curved, base cruck, tops of the blades are truncated by the first transverse member such as by a tie beam. Raised cruck, blades land on masonry wall, and extend to the ridge, middle cruck, blades land on masonry wall, and are truncated by a collar. Upper cruck, blades land on a tie beam, very similar to knee rafters, jointed cruck, blades are made from pieces joined near eaves in a number of ways. See also, hammerbeam roof End cruck is not a style, aisled frames have one or more rows of interior posts. These interior posts typically carry more load than the posts in the exterior walls. This is the concept of the aisle in church buildings, sometimes called a hall church. However, a nave is often called an aisle, and three-aisled barns are common in the U. S. the Netherlands, aisled buildings are wider than the simpler box-framed or cruck-framed buildings, and typically have purlins supporting the rafters. In northern Germany, this construction is known as variations of a Ständerhaus, the frame is often left exposed on the exterior of the building
28.
Dead blow hammer
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A dead blow hammer is a specialized mallet helpful in minimizing damage to the struck surface and in limiting peak striking force, with minimal elastic rebound from the struck surface. The minimal rebound is helpful in avoiding damage to precision work, especially in tight locations. The head of a dead blow hammer is commonly hollow and partially filled with sand, lead shot, or steel shot. If a filled hammer head breaks while in use, it is likely to scatter a spray of the filler particles in the vicinity. Therefore, use of a dead blow hammer may be restricted in certain settings, such as a manufacturing clean room. Some dead blow hammers have completely solid heads, usually made of rubber or resilient plastic, commonly constructed of polyurethane, dead blow hammers regularly appear in solid orange or black. Composite heads and fiberglass handle models are available, with optional shock-absorbent rubber grips. A variant design omits the handle entirely, the dead blow head is gripped directly in the hand, some dead blow hammers have replaceable striking faces, attached by screwing or pressing them into place on the main body of the hammer. These replaceable inserts allow selection of the hardness for the striking face to reduce damage to an object being hammered. Also, worn or damaged inserts can be replaced without discarding the entire handtool, in a conventional solid-head hammer, the force of the entire solid mass of the head is delivered at the moment of impact. Compared to a hammer of similar weight, a dead blow hammer conveys less peak force. At the moment the face of the hammer head contacts the surface being struck, the force imparted by this additional loose mass within the head is not imparted to the struck surface at the moment of contact. Instead, this force is spread out over some period of time, such a blow is less sharp than that of the conventional hammer and feels more dead to the user, hence the name. In auto repair, dead blow hammers are used for chassis work, dislodging stuck parts and sometimes used for hubcap installation. They can be used to pop out small dents when doing auto body repair and they allow controlled use of impact force when performing engine or transmission repair. In maintenance of hydraulic machinery and aerospace work, dead blow hammers are useful in freeing stuck cylinders without damaging their precision-formed surfaces or any nearby bearings, dead blow hammers are used in woodworking to knock joints together or apart without denting the wood pieces being worked on. In metalworking, a dead blow hammer can be used to seat the workpiece against parallels in a machine vise. Dead blow hammers are used in orthopedic surgical procedures
29.
Steel abrasive
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Steel abrasives are steel particles that are used as abrasive or peening media. They are usually available in two different shapes that address different industrial applications, steel shot refers to spherical grains made of molten steel through an atomization process, available in different sizes and hardnesses. Steel grit characterizes grains with an angular shape. These grains are obtained by crushing steel shot, therefore they exhibit sharp edges, harder than steel shot, it is also available in different sizes and hardnesses. Most steel abrasives are made of a high-carbon steel composition, the best compromise between mechanical properties, efficiency and durability, the most important properties for steel abrasives are hardness, grain size and shape, toughness and cleanliness. The recyclability of steel shot and grit ranges between 2000 and 3000 cycles, due to its high recyclability level, steel shot and grit tend to generate less waste when compared to other expendable abrasives. Steel shot or grit is usually available at different hardness levels, steel shot and grit are used in cleaning applications for removal of loose material on metal surfaces. This type of cleaning is common in automotive industry, Surface preparation is as a series of operations including cleaning and physical modification of a surface. The steel shots are employed in shot blasting machines. Steel grit is used in cutting hard stones, such as granite, the grit is used in large multi-blade frames which cut the blocks of granite into thin slices. Shot peening is the striking of a metal surface by hard shot particles. These multiple impacts produce a deformation on the surface but also improve the durability of the metal part. The media used in application is spherical rather than angular. The reason is that spherical shots are more resistant to the fracture which happens due to the striking impact, Abrasive blasting Abrasive machining Momber, A. W. 2008, Blast Cleaning Technology, Springer Publ,2009, Stone 2009, World Marketing Handbook, Faenza Editrice, ISBN 978-88-8138-124-1 Schulze, V.2006, Modern Mechanical Surface Treatment, Wiley-VCH, Verlag GmbH & Co
30.
Shot (pellet)
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Shot is a collective term for small balls or pellets, often made of lead. Lead shot is used for a variety of other purposes such as filling cavities with dense material for weight/balance. Some versions may be plated with other metals, lead shot was originally made by pouring molten lead through screens into water, forming what was known as swan shot, and, later, more economically mass-produced at higher quality using a shot tower. The Bliemeister method has supplanted the shot tower method since the early 1960s, the process was patented in 1782. The process was later brought above ground through the building of shot towers, molten lead would be dropped from the top of the tower. Like most liquids, surface tension makes drops of lead become near-spherical as they fall. When the tower is high enough, the droplets will solidify while still dropping. Water is usually placed at the bottom of the tower, causing the lead to be cooled immediately after dropping, roundness of manufactured shot produced from the shot tower process is graded by forcing the newly produced shot to roll accurately down inclined planes. Unround shot will naturally roll to the side, for collection, the unround shot was either re-processed in another attempt to make round shot using the shot tower again, or used for applications which did not require round shot. The hardness of lead shot is controlled through adding variable amounts of tin, antimony and arsenic and this also affects its melting point. Hardness is also controlled by the rate of cooling that is used in manufacturing lead shot, the Bliemeister method, named for inventor Louis W. Bliemeister of Los Angeles, CA, is a process for making lead shot in small sizes from about #7 through about #9. In this process, molten lead is dripped from small orifices and dropped approximately 1 inch into a hot liquid, the roundness of the lead shot depends on the angle of the inclined surfaces as well as the temperature of the liquid coolant. Various coolants have successfully used, ranging from diesel fuel to antifreeze. After the lead shot cools, it is washed, then dried, the process of rapidly chilling lead shot during its manufacturing process causes the shot to become harder than it would otherwise be if allowed to cool more slowly. Soft lead shot is more readily deformed during the firing process by the effects of chokes. The manufacture of non-lead shot differs from that of lead, with compression molding used to some alloys. Shot is available in sizes for different applications. The size of numbered shot decreases as the number increases, in hunting, some sizes are traditionally used for certain game, or certain shooting situations, although there is overlap and subjective preference
31.
Impulse (physics)
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In classical mechanics, impulse is the integral of a force, F, over the time interval, t, for which it acts. Since force is a quantity, impulse is also a vector in the same direction. Impulse applied to an object produces an equivalent vector change in its linear momentum, the SI unit of impulse is the newton second, and the dimensionally equivalent unit of momentum is the kilogram meter per second. The corresponding English engineering units are the pound-second and the slug-foot per second, a resultant force causes acceleration and a change in the velocity of the body for as long as it acts. Conversely, a force applied for a long time produces the same change in momentum—the same impulse—as a larger force applied briefly. This is often called the impulse-momentum theorem, as a result, an impulse may also be regarded as the change in momentum of an object to which a resultant force is applied. Impulse has the units and dimensions as momentum. In the International System of Units, these are kg·m/s = N·s, in English engineering units, they are slug·ft/s = lbf·s. The term impulse is also used to refer to a force or impact. This type of impulse is often idealized so that the change in momentum produced by the force happens with no change in time and this sort of change is a step change, and is not physically possible. However, this is a model for computing the effects of ideal collisions. The application of Newtons second law for variable mass allows impulse, in the case of rockets, the impulse imparted can be normalized by unit of propellant expended, to create a performance parameter, specific impulse. This fact can be used to derive the Tsiolkovsky rocket equation, which relates the vehicles propulsive change in velocity to the specific impulse. Wave–particle duality defines the impulse of a wave collision, the preservation of momentum in the collision is then called phase matching. Applications include, Compton effect nonlinear optics Acousto-optic modulator Electron phonon scattering Serway, Raymond A. Jewett, John W. Physics for Scientists, Physics for Scientists and Engineers, Mechanics, Oscillations and Waves, Thermodynamics
32.
Tool
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A tool is any physical item that can be used to achieve a goal, especially if the item is not consumed in the process. Tool use by humans dates back millions of years, and other animals are known to employ simple tools. Tools that are used in fields or activities may have different designations such as instrument, utensil, implement, machine, device. The set of tools needed to achieve a goal is equipment, the knowledge of constructing, obtaining and using tools is technology. Anthropologists believe that the use of tools was an important step in the evolution of mankind, because tools are used extensively by both humans and wild chimpanzees, it is widely assumed that the first routine use of tools took place prior to the divergence between the two species. These early tools, however, were made of perishable materials such as sticks. Stone artifacts only date back to about 2.5 million years ago, however, a 2010 study suggests the hominin species Australopithecus afarensis ate meat by carving animal carcasses with stone implements. This finding pushes back the earliest known use of tools among hominins to about 3.4 million years ago. Finds of actual tools date back at least 2.6 million years in Ethiopia, one of the earliest distinguishable stone tool forms is the hand axe. Up until recently, weapons found in digs were the tools of “early man” that were studied. Now, more tools are recognized as culturally and historically relevant, as well as hunting, other activities required tools such as preparing food, “…nutting, leatherworking, grain harvesting and woodworking…” Included in this group are “flake stone tools. “Man the hunter” as the catalyst for Hominin change has been questioned, based on marks on the bones at archaeological sites, it is now more evident that pre-humans were scavenging off of other predators carcasses rather than killing their own food. Mechanical devices experienced an expansion in their use in Ancient Greece and Ancient Rome with the systematic employment of new energy sources. Their use expanded through the Dark Ages with the addition of windmills, machine tools occasioned a surge in producing new tools in the industrial revolution. Advocates of nanotechnology expect a similar surge as tools become microscopic in size, one can classify tools according to their basic functions, Cutting and edge tools, such as the knife, scythe or sickle, are wedge-shaped implements that produce a shearing force along a narrow face. Ideally, the edge of the needs to be harder than the material being cut or else the blade will become dulled with repeated use. But even resilient tools will require periodic sharpening, which is the process of removing deformation wear from the edge, other examples of cutting tools include gouges and drill bits. Moving tools move large and tiny items, many are levers which give the user a mechanical advantage
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Stone Age
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The Stone Age was a broad prehistoric period during which stone was widely used to make implements with an edge, a point, or a percussion surface. The period lasted roughly 3.4 million years, and ended between 8700 BCE and 2000 BCE with the advent of metalworking, bone tools were used during this period as well but are rarely preserved in the archaeological record. The Stone Age is further subdivided by the types of tools in use. According to the age and location of the current evidence, the cradle of the genus is the East African Rift System, especially toward the north in Ethiopia, where it is bordered by grasslands. The closest relative among the living primates, the genus Pan, represents a branch that continued on in the deep forest. The rift served as a conduit for movement into southern Africa and also north down the Nile into North Africa and through the continuation of the rift in the Levant to the vast grasslands of Asia. The oldest indirect evidence found of stone tool use is fossilised animal bones with tool marks, the oldest stone tools were excavated from the site of Lomekwi 3 in West Turkana, northwestern Kenya, and date to 3.3 million years old. Prior to the discovery of these Lomekwian tools, the oldest known stone tools had been found at sites at Gona, Ethiopia, on the sediments of the paleo-Awash River. All the tools come from the Busidama Formation, which lies above a disconformity, or missing layer, the oldest sites containing tools are dated to 2. 6–2.55 mya. One of the most striking circumstances about these sites is that they are from the Late Pliocene, excavators at the locality point out that. the earliest stone tool makers were skilled flintknappers. The possible reasons behind this seeming abrupt transition from the absence of tools to the presence thereof include. The species who made the Pliocene tools remains unknown, fragments of Australopithecus garhi, Australopithecus aethiopicus and Homo, possibly Homo habilis, have been found in sites near the age of the Gona tools. Innovation of the technique of smelting ore ended the Stone Age, the first most significant metal manufactured was bronze, an alloy of copper and tin, each of which was smelted separately. The Chalcolithic by convention is the period of the Bronze Age. The Bronze Age was followed by the Iron Age, the transition out of the Stone Age occurred between 6000 BCE and 2500 BCE for much of humanity living in North Africa and Eurasia. Note the Rudna Glava mine in Serbia, Ötzi the Iceman, a mummy from about 3300 BCE carried with him a copper axe and a flint knife. In regions such as Sub-Saharan Africa, the Stone Age was followed directly by the Iron Age, the Middle East and southeastern Asian regions progressed past Stone Age technology around 6000 BCE. Europe, and the rest of Asia became post–Stone Age societies by about 4000 BCE, the proto-Inca cultures of South America continued at a Stone Age level until around 2000 BCE, when gold, copper and silver made their entrance
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Percussion mallet
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A percussion mallet or beater is an object used to strike or beat a percussion instrument in order to produce its sound. Some mallets, such as a wand, are normally used only with a specific instrument. Some mallets, such as mallets, are normally just called mallets, others have more specialised names including, Drum sticks, of many types. Wands used to strike a triangle, brushes, used particularly with snare drum but also with many other instruments. Tippers used to strike a bodhrán, hammers, also just called mallets or dongers, used with a xylophone. Bachi, used with Japanese taiko drums, Drum sticks are beaters normally used in pairs, with each held in one hand, and are similar to or derived from the snare drum sticks that were subsequently adopted for kit drumming. They are the most general-purpose beaters, and the covers a wide variety of beaters. As well as being a term for a hand-held beater, mallet is also used specifically to refer to a hand-held beater comprising a head connected to a thin shaft. Wrapped mallets are also the mallets of choice to play suspended cymbal, felt mallets or cartwheel mallets have heads composed of layers of felt, held between two steel washers. They are mainly used on untuned percussion, and in the context of kit drumming are referred to as soft sticks, mallet shafts are commonly made of rattan, birch, or synthetic materials such as fibreglass. Different mallets are used primarily to alter the timbre of the instrument being played. Generally, mallets composed of materials will stick to the instrument for longer as they bounce off of it. Mallet choice is left up to the performer, though some compositions specify if a certain sound is desired by the composer. Players frequently employ two mallets in a grip or four mallets in a four-mallet grip, however, use of up to six mallets is not uncommon. Brushes are a set of bristles connected to a handle so that the make a rounded fan shape. They are often used in jazz or blues music, but also in other such as rock, country. The bristles can be made of metal or plastic, the handles are made of wood or aluminum. Some brushes are telescoping so that the bristles can be pulled inside a hollow handle, retracting the bristles also protects the brush when it is not being used
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Drum stick
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A drumstick is a type of percussion mallet used particularly for playing snare drum, drum kit and some other percussion instruments, and particularly for playing unpitched percussion. Drumsticks generally have all of the characteristics, They are normally supplied and used in pairs. They are held in the hands, most often one in each hand and they may be used to play at least some sort of drum. They are normally used only for untuned percussion, the archetypical drumstick is turned from a single piece of wood, most commonly of hickory, less commonly of maple, and least commonly but still in significant numbers, of oak. Drumsticks of the form are also made from metal, carbon fibre. The tip or bead is the part most often used to strike the instrument, in the 1970s, an acetal tip was introduced, designed by Ken Drinan and Paul Kiersted. Tips of whatever material are of shapes, including acorn, barrel, oval, teardrop, pointed. The shoulder of the stick is the part that tapers towards the tip and it is often used for playing the bell of a cymbal. It can also be used to produce a cymbal crash when applied with a motion to the bow or edge of a cymbal. The shaft is the body of the stick, and is cylindrical for most applications including drum kit and it is used for playing cross stick and applied in a glancing motion to the rim of a cymbal for the loudest cymbal crashes. The butt is the end of the stick to the tip. Some rock and metal musicians use it rather than the tip, plain wooden drumsticks are most commonly described using a number to describe the weight and diameter of the stick followed by one or more letters to describe the tip. A 5A is a common wood tipped rock stick, heavier than a 7A, the numbers are most commonly odd but even numbers are used occasionally, in the range 2 to 9. The most general purpose stick is a 5A, however, there is no one stick for any particular style of music. There are two ways of holding drumsticks, Traditional grip, in which right and left hands use different grips. Matched grip, in which the two hand grips are mirror-image, Traditional grip was developed to conveniently play a snare drum while riding a horse, and was documented and popularised by Sanford A. Moeller in The Art of Snare Drumming. It was the grip for kit drummers in the first half of the twentieth century and remains popular. However the traditional grip has since made a comeback, and both types of grip are used and promoted by leading kit drummers and teachers
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Marimba
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The marimba is a percussion instrument consisting of a set of wooden bars struck with mallets to produce musical tones. Resonators suspended underneath the bars amplify their sound and this instrument is a type of idiophone, but with a more resonant and lower-pitched tessitura than the xylophone. The marimba was developed in Central America by African slaves, and descended from its ancestral balafon instrument, Marimba is now the national instrument of Guatemala and Costa Rica. Modern uses of the marimba include solo performances, woodwind and brass ensembles, marimba concertos, jazz ensembles, marching band, drum and bugle corps, contemporary composers have used the unique sound of the marimba more and more in recent years. A player of the marimba can be called a marimbist or a marimba player, xylophones are widely used in music of west and central Africa. The name marimba stems from Bantu marimba or malimba, xylophone, the instrument itself is present, but is called balafon or heri in Mali and/or Guinea, while its known as gyil among the Akan peoples in and around Ghana. The word marimba and derivative words is used widely in East, other sources credit the creation of the marimba and the kalimba to Queen Marimba of the Wakambi people, who live south of Lake Victoria. In the Swahili language imba means song, Marimba, is said to be the mother of song and the creator of all the instruments, including the marimba. Mama means mother in Kiswahili, so it makes sense that the word mother would be combined with the word for song. The karimba is also said to have created by Queen Marimba. In much of East & Central Africa the karimba is seen as a version of the marimba. Diatonic xylophones were introduced to Central America in the 16th or 17th century, the first historical record of Mayan musicians using gourd resonator marimbas in Guatemala was made in 1680, by the historian Domingo Juarros. It became more widespread during the 18th and 19th centuries, as Mayan, in 1821, the marimba was proclaimed the national instrument of Guatemala in its independence proclamation. The gourd resonators were later replaced by harmonic wooden boxes, variants with slats made of steel, glass or bamboo instead of wood appeared during the 19th century. In 1892, Corazón de Jesús Borras Moreno, a musician from Chiapas, expanded marimba to include the chromatic scale by adding another row of sound bars, the name marimba was later applied to the orchestra instrument inspired by the Latin American model. In the United States, companies like Deagan and Leedy company adapted the Latino American instruments for use in western music, metal tubes were used as resonators, fine-tuned by rotating metal discs at the bottom, lowest note tubes were U-shaped. The marimbas were first used for music and dance, such as Vaudeville theater. Clair Omar Musser was a proponent of marimba in the United States at the time
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Xylophone
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The xylophone is a musical instrument in the percussion family that consists of wooden bars struck by mallets. The term xylophone may be used generally, to all such instruments such as the marimba, balafon. The term is popularly used to refer to similar instruments of the lithophone and metallophone types. The bars of metal sound more high pitched than the wooden ones, the modern western xylophone has bars of rosewood, padauk, or various synthetic materials such as fiberglass or fiberglass-reinforced plastic which allows a louder sound. Some can be as small a range as 2½ octaves but concert xylophones are typically 3½ or 4 octaves, the xylophone is a transposing instrument, its parts are written one octave below the sounding notes. Xylophones should be played with hard rubber, polyball, or acrylic mallets. Sometimes medium to hard rubber mallets, very hard core, or yarn mallets are used for softer effects, lighter tones can be created on xylophones by using wooden-headed mallets made from rosewood, ebony, birch, or other hard woods. Concert xylophones have tube resonators below the bars to enhance the tone, frames are made of wood or cheap steel tubing, more expensive xylophones feature height adjustment and more stability in the stand. In other music cultures some versions have gourds that act as Helmholtz resonators, others are trough xylophones with a single hollow body that acts as a resonator for all the bars. Old methods consisted of arranging the bars on tied bundles of straw, ancient mallets were made of willow wood with spoon-like bowls on the beaten ends. The instrument has obscure, ancient origins, according to Nettl, it originated in southeast Asia and came to Africa c. AD500 when a group of Malayo-Polynesian speaking peoples migrated to Africa, one piece of evidence for this is the similarity between East African xylophone orchestras and Javanese and Balinese gamelan orchestras. This, however has been questioned by ethnomusicologist and linguist Roger Blench who posits an independent origin in Africa, the xylophone-like ranat was used in Hindu regions. Java and Bali use xylophones in gamelan ensembles and they still have traditional significance in Africa, Malaysia, Melanesia, Indonesia, Thailand, Myanmar, and regions of the Americas. The term marimba is also applied to traditional folk instruments such as the West Africa balafon. Early forms were constructed of bars atop a gourd, the wood is first roasted around a fire before shaping the key to achieve the desired tone. A skilled maker can produce startling amplification, the mallets used to play dibinda and mbila have heads made from natural rubber taken from a wild creeping plant. This usually doubles an already rapid rhythmic pulse that may also co-exist with a counter-rhythm, the Mbila is associated with the Chopi people of the Inhambane Province, in southern Mozambique
38.
Glockenspiel
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A glockenspiel is a percussion instrument composed of a set of tuned keys arranged in the fashion of the keyboard of a piano. In this way, it is similar to the xylophone, however, the glockenspiel, moreover, is usually smaller and higher in pitch. In German, a carillon is also called a Glockenspiel, while in French, in music scores the glockenspiel is sometimes designated by the Italian term campanelli. When used in a marching or military band, the bars are mounted in a portable case and held vertically. However, sometimes the bars are held using a harness similar to a marching snare harness. In orchestral use, the bars are mounted horizontally, a pair of hard, unwrapped mallets, generally with heads made of plastic or metal, are used to strike the bars, although mallet heads can also be made of rubber. If laid out horizontally, a keyboard glockenspiel may be contrived by adding a keyboard to the instrument to facilitate playing chords, another method of playing chords is to use four mallets, two per hand. The glockenspiel is limited to the register, and usually covers about two and a half to three octaves, but can also reach up to three and a half octaves. The glockenspiel is an instrument, its parts are written two octaves below the sounding notes. When struck, the give an very pure, bell-like sound. Glockenspiels are quite popular and appear in almost all genres of music ranging from hip-hop to jazz. A keyboard-operated glockenspiel, as played by Danny Federici on such hit songs as Born to Run and Hungry Heart, is considered part of Bruce Springsteen, john Lennon also plays it on Only a Northern Song. Panic. at the Disco have used glockenspiel in several of their songs, including their hits I Write Sins Not Tragedies and Build God, Then Well Talk. Radiohead have used glockenspiel on their single No Surprises as well as on The Tourist, Lull, Morning Bell/Amnesiac, Sit Down/Stand Up, songs From the Wood, Heavy Horses and Stormwatch. Solo glockenspiel can be heard briefly, but notably at the beginning of Shostakovichs 15th Symphony, a modern example of the glockenspiel can be heard in Steve Reichs 1970–71 composition Drumming, in which the glockenspiel plays a major role in the third and fourth movements. Other instruments that work on the same principle as the glockenspiel include the marimba. The Dulcitone has a sound to the glockenspiel since its sound is made by hammers striking tuning forks. The dulcitone uses soft hammers which damp the forks, compared to the hammers of the glockenspiel
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Metallophone
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A metallophone is any musical instrument consisting of tuned metal bars which are struck to make sound, usually with a mallet. Metallophones have been used in music in Asia for thousands of years, there are several different types used in Balinese and Javanese gamelan ensembles, including the gendér, gangsa and saron. These instruments have a row of bars, tuned to the distinctive pelog or slendro scales. The Western glockenspiel and vibraphone are also metallophones, they have two rows of bars, in an imitation of the keyboard, and are tuned to the chromatic scale. In music of the 20th century and beyond, the word metallophone is sometimes applied specifically to a row of metal bars suspended over a resonator box. Metallophones tuned to the scale are often used in schools, Carl Orff used diatonic metallophones in several of his pieces. Metallophones with microtonal tunings are used in Iannis Xenakis Pléïades and in the music of Harry Partch, metallophones are a subset of Hornbostel-Sachs category 111.22 Percussion plaques. Celesta Fangxiang Gangsa Gendér Glockenspiel Jegogan Jublag Kulintang a Tiniok/Sarunay Ranat ek lek Ranat thum lek Roneat dek Roneat thong Saron Slentem Step bell Steel marimbaphone Ugal Vibraphone
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Vibraphone
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The vibraphone is a musical instrument in the struck idiophone subfamily of the percussion family. The vibraphone resembles the xylophone, marimba, and glockenspiel, each bar is paired with a resonator tube that has a motor-driven butterfly valve at its upper end. The valves are mounted on a shaft, which produces a tremolo or vibrato effect while spinning. The vibraphone also has a sustain pedal similar to that on a piano, with the pedal up, the bars are all damped and produce a shortened sound. With the pedal down, they sound for several seconds, the vibraphone is commonly used in jazz music, in which it often plays a featured role and was a defining element of the sound of mid-20th-century Tiki lounge exotica, as popularized by Arthur Lyman. It is the second most popular solo keyboard percussion instrument in music, after the marimba. It is an instrument in the modern percussion section for orchestras. The first musical instrument called vibraphone was marketed by the Leedy Manufacturing Company in the United States in 1921, however, this instrument differed in significant details from the instrument now called the vibraphone. The Leedy vibraphone achieved a degree of popularity after it was used in the novelty recordings of Aloha Oe and this popularity led J. C. Deagan, Inc. in 1927 to ask its Chief Tuner, Henry Schluter, to develop a similar instrument. Schluters design was more popular than the Leedy design, and has become the template for all instruments now called vibraphone, however, when Deagan began marketing Schluters instrument in 1928, they called it the vibraharp. The name derived from similar aluminum bars that were mounted vertically, since Deagan trademarked the name, others were obliged to use the earlier vibraphone for their instruments incorporating the newer design. The name confusion continues, even to the present, but over time vibraphone became significantly more popular than vibraharp, by 1974, the Directory of the D. C. Federation of Musicians listed 39 vibraphone players and 3 vibraharp players, the initial purpose of the vibraphone was to add to the large arsenal of percussion sounds used by vaudeville orchestras for novelty effects. This use was quickly overwhelmed in the 1930s by its development as a jazz instrument, the use of the vibraphone in jazz was pioneered by Paul Barbarin, the drummer with Luis Russells band. Bergerault, of Ligueil, France also began manufacturing vibraphones in the 1930s, Deagan struck endorsement deals with many of the leading players, including Lionel Hampton and Milt Jackson. The Deagan company went out of business in the 1980s, its trademark, Yamaha continues to make percussion instruments based on Deagan designs. In 1948, the Musser Mallet Company was founded by Clair Omar Musser, the Musser company continues to manufacture vibraphones as part of the Ludwig Drum Company. The standard modern instrument has a range of three octaves, from the F below middle C, larger three-and-a-half or four octave models from the C below middle C are also becoming more common
41.
Mallet percussion
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A mallet percussion instrument is a melodic percussion instrument played in a particular fashion, with mallets. Mallet percussion includes, xylophone glockenspiel vibraphone marimba crotales balafon aluphone The use of mallet percussion dates back at least 4,000 years to the first known xylophone. Mallet percussion was first used in a modern European orchestra in 1874, modern mallet percussion instruments exist at many levels, from toy glockenspiels such as the Pixiphone popularly known as xylophones, to orchestral instruments, and including many folk instruments. Many of these are diatonic, while professional mallet percussion instruments are chromatic keyboard percussion instruments, although all mallet percussion is played with types of percussion mallet, the converse is not true. Not all instruments played with percussion mallets are termed mallet percussion instruments, rather, the term percussion mallet is applied very widely, including for example tympani sticks and even drum sticks and the beaters used for untuned gongs. Melodic percussion instrument Keyboard percussion instrument Danse macabre Music for Mallet Instruments, Voices and Organ Marimba Concerto The Sorcerers Apprentice by Paul Dukas
42.
Rattan
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Rattan is the name for roughly 600 species of old world climbing palms belonging to subfamily Calamoideae. Rattan is also known as manila, or malacca, named after the ports of shipment Manila and Malacca City, the climbing habit is associated with the characteristics of its flexible woody stem, derived typically from a secondary growth, makes rattan a liana rather than a true wood. Calamoideae also includes tree palms such as Raphia and Metroxylon and shrub palms such as Salacca and they dont have spinose stems and climb by means of their reflexed terminal leaflets. Of these only Desmoncus spp. furnish stems of sufficiently good quality to be used as rattan cane substitutes, there are 13 different genera of rattans that include around 600 species. The largest rattan genus is Calamus, distributed in Asia except for one species represented in Africa, the rattan genera and their distribution, In Uhl & Dransfield, and also Dransfield & Manokaran, a great deal of basic introductory information is available. Available rattan floras and monographs by region, Uses by taxon, rattans are also superficially similar to bamboo. Unlike bamboo, rattan stems are solid, and most species need structural support, many rattans have spines which act as hooks to aid climbing over other plants, and to deter herbivores. Rattans have been known to grow up to hundreds of metres long, most of the worlds rattan population exist in Indonesia, distributed among the islands Borneo, Sulawesi, and Sumbawa. The rest of the supply comes from the Philippines, Sri Lanka, Malaysia. In forests where rattan grows, its value can help protect forest land, by providing an alternative to loggers who forgo timber logging. Rattan is much easier to harvest, requires simpler tools and is easier to transport. It also grows faster than most tropical wood. This makes it a tool in forest maintenance, since it provides a profitable crop that depends on rather than replaces trees. It remains to be seen whether rattan can be as profitable or useful as the alternatives, rattans are threatened with overexploitation, as harvesters are cutting stems too young and reducing their ability to resprout. Unsustainable harvesting of rattan can lead to forest degradation, affecting overall forest ecosystem services, the use of toxic chemicals and petrol in the processing of rattan affects soil, air and water resources, and also ultimately peoples health. Meanwhile, the method of rattan production is threatening the plants long-term supply. Generally, raw rattan is processed into products to be used as materials in furniture making. The various species of rattan range from millimetres up to 5–7 cm in diameter
43.
Birch
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A birch is a thin-leaved deciduous hardwood tree of the genus Betula, in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae, the genus Betula contains 30 to 60 known taxa of which 11 are on the IUCN2011 Green List of Threatened Species. They are a typically rather short-lived pioneer species widespread in the Northern Hemisphere, particularly in northern temperate, Birch species are generally small to medium-sized trees or shrubs, mostly of northern temperate and boreal climates. The simple leaves are alternate, singly or doubly serrate, feather-veined and they often appear in pairs, but these pairs are really borne on spur-like, two-leaved, lateral branchlets. The fruit is a samara, although the wings may be obscure in some species. They differ from the alders in that the female catkins are not woody and disintegrate at maturity, falling apart to release the seeds, unlike the woody, cone-like female alder catkins. The bark of all birches is characteristically marked with long, horizontal lenticels and its decided color gives the common names gray, white, black, silver and yellow birch to different species. The buds form early and are grown by midsummer, all are lateral, no terminal bud is formed. The wood of all the species is close-grained with satiny texture, staminate aments are pendulous, clustered or solitary in the axils of the last leaves of the branch of the year or near the ends of the short lateral branchlets of the year. They form in autumn and remain rigid during the winter. The scales of the staminate aments when mature are broadly ovate, rounded, yellow or orange color below the middle, each scale bears two bractlets and three sterile flowers, each flower consisting of a sessile, membranaceous, usually two-lobed, calyx. Each calyx bears four short filaments with one-celled anthers or strictly, the pistillate aments are erect or pendulous, solitary, terminal on the two-leaved lateral spur-like branchlets of the year. The pistillate scales are oblong-ovate, three-lobed, pale yellow green often tinged with red and these scales bear two or three fertile flowers, each flower consisting of a naked ovary. The ovary is compressed, two-celled, and crowned with two styles, the ovule is solitary. Each scale bear a small, winged nut that is oval. Betula species are organised into five subgenera, pendula and B. pubescens confused, though they are distinct species with different chromosome numbers. This root is derived from *bʰreh₁ǵ- ‘to shine’, in reference to the birchs white bark. The Proto-Germanic rune berkanan is named after the birch, the generic name betula is from Latin, which is a diminutive borrowed from Gaulish betua
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Fiberglass
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Fiberglass is a type of fiber-reinforced plastic where the reinforcement fiber is specifically glass fiber. The glass fiber may be arranged, flattened into a sheet. The plastic matrix may be a polymer matrix – most often based on thermosetting polymers such as epoxy, polyester resin. The glass fibers are made of various types of glass depending upon the fiberglass use and these glasses all contain silica or silicate, with varying amounts of oxides of calcium, magnesium, and sometimes boron. To be used in fiberglass, glass fibers have to be made very low levels of defects. Fiberglass is a lightweight material and is used for many products. Although it is not as strong and stiff as composites based on fiber, it is less brittle. Its bulk strength and weight are also better than many metals, other common names for fiberglass are glass-reinforced plastic, glass-fiber reinforced plastic or GFK. Because glass fiber itself is referred to as fiberglass, the composite is also called fiberglass reinforced plastic. This article will adopt the convention that fiberglass refers to the glass fiber reinforced composite material. A patent for this method of producing glass wool was first applied for in 1933, Owens joined with the Corning company in 1935 and the method was adapted by Owens Corning to produce its patented fibreglas in 1936. Originally, fibreglas was a wool with fibers entrapping a great deal of gas, making it useful as an insulator. A suitable resin for combining the fibreglass with a plastic to produce a material was developed in 1936 by du Pont. The first ancestor of modern polyester resins is Cyanamids resin of 1942, peroxide curing systems were used by then. With the combination of fiberglass and resin the gas content of the material was replaced by plastic and this reduced the insulation properties to values typical of the plastic, but now for the first time the composite showed great strength and promise as a structural and building material. Confusingly, many glass fiber composites continued to be called fiberglass, ray Greene of Owens Corning is credited with producing the first composite boat in 1937, but did not proceed further at the time due to the brittle nature of the plastic used. In 1939 Russia was reported to have constructed a boat of plastic materials. The first car to have a body was a 1946 prototype of the Stout Scarab
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Felt
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Felt is a textile material that is produced by matting, condensing and pressing fibers together. Felt can be made of fibers such as wool, or from synthetic fibers such as petroleum-based acrylic or acrylonitrile or wood pulp-based rayon. Felt from wool is considered to be the oldest known textile, many cultures have legends as to the origins of felt making. Sumerian legend claims that the secret of feltmaking was discovered by Urnamman of Lagash, the story of Saint Clement and Saint Christopher relates that while fleeing from persecution, the men packed their sandals with wool to prevent blisters. At the end of their journey, the movement and sweat had turned the wool into felt socks, feltmaking is still practised by nomadic peoples in Central Asia, where rugs, tents and clothing are regularly made. Some of these are items, such as the classic yurt, while others are designed for the tourist market. Wrapping the properly arranged fiber in a sturdy, textured material, such as a mat or burlap. The felted material may be finished by fulling, only certain types of fiber can be wet felted successfully. Most types of fleece, such as those taken from the alpaca or the Merino sheep, one may also use mohair, angora, or hair from rodents such as beavers and muskrats. These types of fiber are covered in scales, similar to the scales found on a strand of human hair. Heat, motion, and moisture of the causes the scales to open, while agitating them causes them to latch onto each other. There is a theory that the fibers wind around each other during felting. Plant fibers and synthetic fibers will not wet felt, needle felting is a method of creating felted objects without using water. The special needles used to make 3D sculpture, jewelry, adornments and 2D art have notches along the shaft of the needle that catch fibers and tangle them with other fibers to produce felt. These notches are sometimes erroneously called barbs, but barbs are protrusion, there are many sizes and types of notched needles for different uses while working. Needle felting is used in processes as well as in individual crafting. Invented in the mid 17th century and used until the mid-20th centuries, beaver, rabbit or hare skins were treated with a dilute solution of the mercury compound mercuric nitrate. The skins were dried in an oven where the fur at the sides turned orange
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Rope
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A rope is a group of yarns, plies, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting, as a result, they cannot be used for pushing or similar compressive applications. Rope is thicker and stronger than similarly constructed cord, line, string, fiber rope is made from fiber, whereas wire rope is made from wire. Rope may be constructed of any long, stringy, fibrous material, synthetic fibre ropes are significantly stronger than their natural fibre counterparts, but also possess certain disadvantages, including slipperiness. Common natural fibres for rope are manila hemp, hemp, feathers, linen, cotton, coir, jute, straw, synthetic fibres in use for rope-making include polypropylene, nylon, polyesters, polyethylene, Aramids and acrylics. Some ropes are constructed of mixtures of several fibres or use co-polymer fibres, wire rope is made of steel or other metal alloys. Ropes have been constructed of fibrous materials such as silk, wool, and hair. Rayon is a fibre used to make decorative rope. The twist of the strands in a twisted or braided rope serves not only to keep a rope together, without any twist in the rope, the shortest strand would always be supporting a much higher proportion of the total load. Rope is of paramount importance in fields as diverse as construction, seafaring, exploration, sports, theatre, and communications, to fasten rope, many types of knots have been invented for countless uses. Pulleys redirect the force to another direction, and can create mechanical advantage so that multiple strands of rope share a load. Winches and capstans are machines designed to pull ropes, such ropes normally use a kernmantle construction, as described below. Static ropes, used for example in caving, rappelling, and rescue applications, are designed for minimal stretch, the UIAA, in concert with the CEN, sets climbing-rope standards and oversees testing. Any rope bearing a GUIANA or CE certification tag is suitable for climbing, climbing ropes, however, do cut easily when under load. Keeping them away from sharp rock edges is imperative, rock climbing ropes come with either a designation for single, double or twin use. A single rope is the most common and it is intended to be used by itself, single ropes range in thickness from roughly 9mm to 11mm. Smaller ropes are lighter, but wear out faster, double ropes are thinner ropes, usually 9mm and under, and are intended for use as a pair. These ropes offer a margin or security against cutting, since it is unlikely that both ropes will be cut, but they complicate belaying and leading
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Yarn
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Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, and ropemaking. Thread is a type of yarn intended for sewing by hand or machine, modern manufactured sewing threads may be finished with wax or other lubricants to withstand the stresses involved in sewing. Embroidery threads are yarns specifically designed for hand or machine embroidery, the word yarn comes from Middle English, from the Old English gearn, akin to Old High Germans garn yarn, Greeks chordē string, and Sanskrits hira band. Yarn can be made from a number of natural or synthetic fibers, many types of yarn are made differently though. There are two types of yarn, spun and filament. The most common plant fiber is cotton, which is spun into fine yarn for mechanical weaving or knitting into cloth. Cotton and polyester are the most commonly spun fibers in the world, cotton is grown throughout the world, harvested, ginned, and prepared for yarn spinning. Polyester is extruded from polymers derived from gas and oil. Synthetic fibers are generally extruded in continuous strands of gel-state materials and these strands are drawn, annealed, and cured to obtain properties desirable for later processing. Synthetic fibers come in three forms, staple, tow, and filament. Staple is cut fibers, generally sold in lengths up to 120mm, tow is a continuous rope of fibers consisting of many filaments loosely joined side-to-side. Filament is a continuous strand consisting of anything from 1 filament to many, synthetic fiber is most often measured in a weight per linear measurement basis, along with cut length. Denier and Dtex are the most common weight to length measures, cut-length only applies to staple fiber. Filament extrusion is sometimes referred to as spinning but most people equate spinning with spun yarn production, the most commonly spun animal fiber is wool harvested from sheep. For hand knitting and hobby knitting, thick, wool and acrylic yarns are frequently used, other animal fibers used include alpaca, angora, mohair, llama, cashmere, and silk. More rarely, yarn may be spun from camel, yak, possum, musk ox, cat, dog, wolf, rabbit, or buffalo hair, and even turkey or ostrich feathers. Natural fibers such as these have the advantage of being slightly elastic and very breathable, while trapping a great deal of air, other natural fibers that can be used for yarn include linen and cotton. These tend to be much less elastic, and retain less warmth than the animal-hair yarns, the finished product will also look rather different from the woollen yarns
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Overtone
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An overtone is any frequency greater than the fundamental frequency of a sound. Using the model of Fourier analysis, the fundamental and the overtones together are called partials, harmonics, or more precisely, harmonic partials, are partials whose frequencies are integer multiples of the fundamental. These overlapping terms are used when discussing the acoustic behavior of musical instruments. The model of Fourier analysis provides for the inclusion of inharmonic partials, when a resonant system such as a blown pipe or plucked string is excited, a number of overtones may be produced along with the fundamental tone. In simple cases, such as for most musical instruments, the frequencies of these tones are the same as the harmonics. Examples of exceptions include the drum, – a timpani whose first overtone is about 1.6 times its fundamental resonance frequency, gongs and cymbals. The human vocal tract is able to produce highly variable amplitudes of the overtones, called formants, most oscillators, from a guitar string to a flute, will naturally vibrate at a series of distinct frequencies known as normal modes. The lowest normal mode frequency is known as the fundamental frequency, often, when an oscillator is excited by, for example, plucking a guitar string, it will oscillate at several of its modal frequencies at the same time. So when a note is played, this gives the sensation of hearing other frequencies above the lowest frequency, timbre is the quality that gives the listener the ability to distinguish between the sound of different instruments. The timbre of an instrument is determined by which overtones it emphasizes and that is to say, the relative volumes of these overtones to each other determines the specific flavor or color of sound of that family of instruments. The intensity of each of these overtones is rarely constant for the duration of a note, over time, different overtones may decay at different rates, causing the relative intensity of each overtone to rise or fall independent of the overall volume of the sound. A carefully trained ear can hear these changes even in a single note and this is why the timbre of a note may be perceived differently when played staccato or legato. A driven non-linear oscillator, such as the folds, a blown wind instrument, or a bowed violin string will oscillate in a periodic. This generates the impression of sound at integer multiple frequencies of the known as harmonics, or more precisely. Thus, in music, overtones are often called harmonics, depending upon how the string is plucked or bowed, different overtones can be emphasized. However, some overtones in some instruments may not be of an integer multiplication of the fundamental frequency. High quality instruments are built in such a manner that their individual notes do not create disharmonious overtones. This is illustrated by the following, Consider a guitar string and this dead length actually varies from string to string, being more pronounced with thicker and/or stiffer strings
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Whac-A-Mole
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Whac-A-Mole is a popular arcade redemption game invented in 1976 by Aaron Fechter of Creative Engineering, Inc. In Japan, モグラ退治 is a arcade game invented in 1975 by Kazuo Yamada of TOGO, based on ten of the designers pencil sketches from 1974. It can also be found at Japanese festivals. A typical Whac-A-Mole machine consists of a large, waist-level cabinet with five holes in its top, each hole contains a single plastic mole and the machinery necessary to move it up and down. Once the game starts, the moles will begin to pop up from their holes at random, the object of the game is to force the individual moles back into their holes by hitting them directly on the head with the mallet, thereby adding to the players score. The quicker this is done the higher the score will be. The cabinet has a three-digit readout of the current players score and, on later models, the mallet is usually attached to the game by a rope in order to prevent patrons from walking away with it. Current versions of the Whac-A-Mole include three displays for Bonus Score, High Score as well as current game score, home versions, as distributed by Bobs Space Racers, include one display to show the current score. If the player does not strike a mole within a time or with enough force. After a designated time limit, the ends, regardless of the skill of the player. The final score is based upon the number of moles that the player struck, in addition to the single-player game described above, there is a multi-player game, most often found at amusement parks. In most versions, striking a mole is worth ten points, the winner receives a prize, typically a small stuffed animal, which can be traded up for a larger stuffed animal should the player win again. Game play options have become more adjustable, allowing the operator and/or owner to selectively alter the score, hits points. The original Whac-A-Mole game inspired the first genre of games with a violent aspect as central to their user experience, researchers have used Whac-A-Mole and its variations to study the violent aspects of these games. The Whac-A-Mole game trademark is owned by Bobs Space Racers, machines with similar gameplay are sold under other names. Whac-A-Mole has also been the basis for a number of games and mobile games that are similar in play. Engineer Tim Hunkin built and installed a Whack a Banker machine at Southwold Pier in England in 2009 made from parts of a previous Whack a Warden machine, the moles are mounted on rods and raised by a lever and crank system. When the user strikes the mole, a microswitch is activated by a pin housed within the mole, the timing of the moles was originally controlled by tones from an audio tape which then drive an air cylinder system, however, this may have been updated more recently
The dictionary definition of mallet at Wiktionary
