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Glue
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 eithe ... [...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] |
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] |
Papyrus
Papyrus ( ) is a material similar to thick paper that was used in ancient times as a writing surface. It was made from the pith of the papyrus plant, ''Cyperus papyrus'', a wetland sedge. ''Papyrus'' (plural: ''papyri'' or ''papyruses'') can also refer to a document written on sheets of such material, joined side by side and rolled up into a scroll, an early form of a book. Papyrus was first known to have been used in Egypt (at least as far back as the First Dynasty of Egypt, First Dynasty), as the papyrus plant was once abundant across the Nile Delta. It was also used History of the Mediterranean, throughout the Mediterranean region. Apart from writing material, ancient Egyptians employed papyrus in the construction of other Artifact (archaeology), artifacts, such as reed boats, mats, rope, sandals, and baskets. History Papyrus was first manufactured in Egypt as far back as the third millennium BCE.H. Idris Bell and T.C. Skeat, 1935"Papyrus and its uses"(British Museum pam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Le Moustier
Le Moustier is an archeological site consisting of two rock shelters in Peyzac-le-Moustier, a village in the Dordogne, France. It is known for a complete skeleton of the species ''Homo neanderthalensis'' that was discovered in 1908. The Mousterian tool culture is named after Le Moustier, which was first excavated from 1863 by the Englishman Henry Christy and the Frenchman Édouard Lartet. In 1979, Le Moustier was inscribed on the UNESCO World Heritage List along with other nearby archeological sites as part of the '' Prehistoric Sites and Decorated Caves of the Vézère Valley''. Skeleton The skeleton known as "Le Moustier" is estimated to be approximately 45,000 years old. The characteristics of its skull include a large nasal cavity and a somewhat less developed brow ridge and occipital bun, as might be expected in a juvenile. After discovery, the skull was dismantled, cast and reconstructed at least four times. During this process, the skull received considerable amoun ... [...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] |
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] |
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] |
Adhesion
Adhesion is the tendency of dissimilar particles or interface (matter), surfaces to cling to one another. (Cohesion (chemistry), Cohesion refers to the tendency of similar or identical particles and surfaces to cling to one another.) The forces that cause adhesion and cohesion can be divided into several types. The intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion. In addition to the cumulative magnitudes of these intermolecular forces, there are also certain emergent mechanical effects. Surface energy Surface energy is conventionally defined as the work (physics), work that is required to build an area of a particular surface. Another way to view the surface energy is to relate it to the work required to cleave a bulk sample, creating two surfaces. If the new surfaces are identical, the surface energy γ of each surface is equal to h ... [...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] |
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] |
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] |
