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Glues
Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantages over other binding techniques such as sewing, mechanical fastenings, and welding. These include the ability to bind different materials together, the more efficient distribution of stress across a joint, the cost-effectiveness of an easily mechanized process, and greater flexibility in design. Disadvantages of adhesive use include decreased stability at high temperatures, relative weakness in bonding large objects with a small bonding surface area, and greater difficulty in separating objects during testing. Adhesives are typically organized by the method of adhesion followed by ''reactive'' or ''non-reactive'', a term which refers to whether the adhesive chemically reacts in order to harden. Alternatively, they can be organized either ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Glue
Animal glue is an adhesive that is created by prolonged boiling of animal connective tissue in a process called Rendering (animal products), rendering. In addition to being used as an adhesive, it is used for coating and sizing, in decorative composition ornaments, and as a clarifying agent. These protein colloid glues are formed through hydrolysis of the collagen from skins, bones, tendons, and other tissues, similar to gelatin. The word ''collagen'' itself derives from Greek language, Greek (), meaning 'glue'. These proteins form a molecular bond with the glued object. Conventionally, keratin#glue, keratin glues, while made from animal parts like horns and hooves, are not considered animal glues as they are not collagen glues. Stereotypically, the animal in question is a horse, and horses that are euthanized are often said to have been "sent to the glue factory". However, other animals are also used, including cattle, rabbits and fish. History Early uses Animal glue has exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casein
Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of the proteins in breast milk, human milk. Sheep's milk, Sheep and cow milk have a higher casein content than other types of milk with human milk having a particularly low casein content. Casein is the primary emulsifier in milk, that is, it helps in mixing oils, fats, and water in milk. Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive. The most common form of casein is sodium caseinate (historically called nutrose), which is a very efficient emulsifier. Casein is secreted into milk from mammary cells in the form of colloidal casein micelles, a type of biomolecular condensate. As a food source, casein supplies amino acids, carbohydrates, and two essential elements, calcium and phosphoru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tendon
A tendon or sinew is a tough band of fibrous connective tissue, dense fibrous connective tissue that connects skeletal muscle, muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tension (physics), tension. Tendons, like ligaments, are made of collagen. The difference is that ligaments connect bone to bone, while tendons connect muscle to bone. There are about 4,000 tendons in the adult human body. Structure A tendon is made of dense regular connective tissue, whose main cellular components are special fibroblasts called tendon cells (tenocytes). Tendon cells synthesize the tendon's extracellular matrix, which abounds with densely-packed collagen fibers. The collagen fibers run parallel to each other and are grouped into fascicles. Each fascicle is bound by an endotendineum, which is a delicate loose connective tissue containing thin collagen fibrils and elastic fibers. A set of fascicles is bound by an epitenon, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birch Bark Tar
Birch bark tar (sometimes referred to as birch bark pitch) is a substance that is synthesized by dry distillation of birch tree bark. Chemical composition Birch bark tar is mainly composed of triterpenoid compounds of the lupane and oleanane family, which can be used as biomarkers to identify birch bark tar in the archaeological record. The most characteristic molecules are betulin and lupeol, which are also present in birch bark. Some of these molecules degrade into other lupane and oleanane skeleton triperpenes. The most commonly found additional molecules are lupenone, betulone, lupa-2,20(29)-dien-28-ol, lupa-2,20(29)-diene and allobetulin. Ancient and modern uses Birch bark tar use as an adhesive began in the Middle Paleolithic. Neanderthals produced tar through dry distillation of birch bark as early as 200,000 years ago. A 2019 study demonstrated that birch bark tar production can be a simpler, more discoverable process by directly burning birch bark under overh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrolean Iceman
Tyrolean may refer to: * Anything from Tyrol (state) Tyrol ( ; ; ) is an Austrian Provinces of Austria, federal state. It comprises the Austrian part of the historical County of Tyrol, Princely County of Tyrol. It is a constituent part of the present-day Euroregion Tyrol–South Tyrol–Trenti ... (Austria), South Tyrol (Italy) or the historical County of Tyrol or region of Tyrol * Tyrolean Zugspitze Cable Car * Tyrolean Airways * Tyrolean hat * Tyrolean traverse, mountaineering manoeuvre * Tyrolean Hound * A type of cement render, applied by a hand-operated machine {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horn (anatomy)
A horn is a permanent pointed projection on the head of various animals that consists of a covering of keratin and other proteins surrounding a core of live bone. Horns are distinct from antlers, which are not permanent. In mammals, true horns are found mainly among the ruminant artiodactyls, in the families Antilocapridae ( pronghorn) and Bovidae ( cattle, goats, antelope etc.). Cattle horns arise from subcutaneous connective tissue (under the scalp) and later fuse to the underlying frontal bone. One pair of horns is usual; however, two or more pairs occur in a few wild species and in some domesticated breeds of sheep. Polycerate (multi-horned) sheep breeds include the Hebridean, Icelandic, Jacob, Manx Loaghtan, and the Navajo-Churro. Horns usually have a curved or spiral shape, often with ridges or fluting. In many species, only males have horns. Horns start to grow soon after birth and continue to grow throughout the life of the animal (except in pronghorns, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mongols
Mongols are an East Asian ethnic group native to Mongolia, China ( Inner Mongolia and other 11 autonomous territories), as well as the republics of Buryatia and Kalmykia in Russia. The Mongols are the principal member of the large family of Mongolic peoples. The Oirats and the Buryats are classified either as distinct ethno-linguistic groups or as subgroups of Mongols. The Mongols are bound together by a common heritage and ethnic identity, descending from the Proto-Mongols. Their indigenous dialects are collectively known as the Mongolian language. The contiguous geographical area in which the Mongols primarily live is referred to as the Mongol heartland, especially in discussions of the Mongols' history under the Mongol Empire. Definition Broadly defined, the term includes the Mongols proper (also known as the Khalkha Mongols), Buryats, Oirats, the Kalmyks and the Southern Mongols. The latter comprises the Abaga Mongols, Abaganar, Aohans, Arkhorchin, Asud, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pozzolana
Pozzolana or pozzuolana ( , ), also known as pozzolanic ash (), is a natural siliceous or siliceous- aluminous material which reacts with calcium hydroxide in the presence of water at room temperature (cf. pozzolanic reaction). In this reaction insoluble calcium silicate hydrate and calcium aluminate hydrate compounds are formed possessing cementitious properties. The designation pozzolana is derived from one of the primary deposits of volcanic ash used by the Romans in Italy, at Pozzuoli. The modern definition of pozzolana encompasses any volcanic material ( pumice or volcanic ash), predominantly composed of fine volcanic glass, that is used as a pozzolan. Note the difference with the term pozzolan, which exerts no bearing on the specific origin of the material, as opposed to pozzolana, which can only be used for pozzolans of volcanic origin, primarily composed of volcanic glass. Historical use Pozzolanas such as Santorin earth were used in the Eastern Mediterranean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slaked Lime
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime ( calcium oxide) is mixed with water. Annually, approximately 125 million tons of calcium hydroxide are produced worldwide. Calcium hydroxide has many names including hydrated lime, caustic lime, builders' lime, slaked lime, cal, and pickling lime. Calcium hydroxide is used in many applications, including food preparation, where it has been identified as E number E526. Limewater, also called milk of lime, is the common name for a saturated solution of calcium hydroxide. Solubility Calcium hydroxide is moderately soluble in water, as seen for many dihydroxides. Its solubility increases from 0.66 g/L at 100 °C to 1.89 g/L at 0 °C. Its solubility product ''K''sp of 5.02 at 25 °C, its dissociation in water is large enough that its solutions are basic according to the following ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marquetry
Marquetry (also spelled as marqueterie; from the French ''marqueter'', to variegate) is the art and craft of applying pieces of wood veneer, veneer to a structure to form decorative patterns or designs. The technique may be applied to case furniture or even seat furniture, to decorative small objects with smooth, veneerable surfaces or to freestanding pictorial panels appreciated in their own right. Marquetry differs from the more ancient craft of inlay, or intarsia, in which a solid body of one material is cut out to receive sections of another to form the surface pattern. The word derives from a Middle French word meaning "inlaid work". Materials The veneers used are primarily woods, but may include bone, ivory, turtle-shell (conventionally called "Tortoiseshell material, tortoiseshell"), mother-of-pearl, pewter, brass or fine metals. Marquetry using colored Straw marquetry, straw was a specialty of some European spa resorts from the end of the 18th century. Many exotic wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood Veneer
Veneer refers to thin slices of wood and sometimes bark that typically are glued onto core panels (typically, wood, particle board or medium-density fiberboard) to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. They are also used in marquetry. Unlike laminates, no two veneer sheets look the same. Plywood consists of three or more layers of veneer. Normally, each is glued with its grain at right angles to adjacent layers for strength. Veneer beading is a thin layer of decorative edging placed around objects, such as jewelry boxes. Veneer is also used to replace decorative papers in wood veneer high pressure laminate. Background Veneering dates back to at least the ancient Egyptians who used expensive and rare wood veneers over cheaper timbers to produce their furniture and sarcophagi. During the Roman Empire, Romans also used veneered work in mass quantities. Production Veneer is obtained either by "peeling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molten Beeswax
Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which increases the substance's temperature to the melting point. At the melting point, the ordering of ions or molecules in the solid breaks down to a less ordered state, and the solid melts to become a liquid. Substances in the molten state generally have reduced viscosity as the temperature increases. An exception to this principle is elemental sulfur, whose viscosity increases in the range of 130 °C to 190 °C due to polymerization. Some organic compounds melt through mesophases, states of partial order between solid and liquid. First order phase transition From a thermodynamics point of view, at the melting point the change in Gibbs free energy ''∆G'' of the substances is zero, but there are non-zero changes in the enthalpy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
