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Rubber Cement
Rubber cement (cow gum in British English) is an adhesive made from elastic polymers (typically latex) mixed in a solvent such as acetone, hexane, heptane or toluene to keep it fluid enough to be used. This makes it part of the class of drying adhesives: as the solvents quickly evaporate, the rubber solidifies, forming a strong yet flexible bond. Composition Rubber cement is simply a mixture of solid rubber in a volatile solvent that will dissolve it. When the cement is applied, the solvent evaporates, leaving the rubber as the adhesive. Almost any rubber (pre-vulcanized or not) can be used. The rubbers used might be natural rubber, gum mastic or gum arabic. Early solvents used included chloroform and benzene. A small percentage of alcohol is often added to the mix. In the United States, current formulations include n-heptane. In the United Kingdom, a product called Marabu-Fixogum uses acetone, while a product called Copydex uses ammonia. Many special compositions include h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubber Cement
Rubber cement (cow gum in British English) is an adhesive made from elastic polymers (typically latex) mixed in a solvent such as acetone, hexane, heptane or toluene to keep it fluid enough to be used. This makes it part of the class of drying adhesives: as the solvents quickly evaporate, the rubber solidifies, forming a strong yet flexible bond. Composition Rubber cement is simply a mixture of solid rubber in a volatile solvent that will dissolve it. When the cement is applied, the solvent evaporates, leaving the rubber as the adhesive. Almost any rubber (pre-vulcanized or not) can be used. The rubbers used might be natural rubber, gum mastic or gum arabic. Early solvents used included chloroform and benzene. A small percentage of alcohol is often added to the mix. In the United States, current formulations include n-heptane. In the United Kingdom, a product called Marabu-Fixogum uses acetone, while a product called Copydex uses ammonia. Many special compositions include h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gum Mastic
Mastic ( el, Μαστίχα) is a resin obtained from the mastic tree (''Pistacia lentiscus''). It is also known as tears of Chios, being traditionally produced on the island Chios, and, like other natural resins, is produced in "tears" or droplets. Mastic is excreted by the resin glands of certain trees and dries into pieces of brittle, translucent resin. When chewed, the resin softens and becomes a bright white and opaque gum. The flavor is bitter at first, but after some chewing, it releases a refreshing flavor similar to pine and cedar. History Mastic has been harvested for at least 2,500 years since Greek antiquity. The word ''mastic'' is derived from grc-gre, μαστιχάειν, masticháein, 'to gnash the teeth', which is also the source of the English word ''masticate''. The first mention of actual mastic 'tears' was by Hippocrates. Hippocrates used mastic for the prevention of digestive problems, colds and as a breath freshener. Romans used mastic along with honey, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flammable Liquid
A flammable liquid is a liquid which can be easily ignited in air at ambient temperatures, i.e. it has a flash point at or below nominal threshold temperatures defined by a number of national and international standards organisations. The Occupational Safety and Health Administration (OSHA) of the United States Department of Labor defines a liquid as flammable if it has a flash point at or below 199.4 °F (93 °C). Prior to bringing regulations in line with the United Nations Globally Harmonized System of Classification and Labeling of Chemicals (GHS) in 2012, OSHA considered flammable liquids to be those with a flash point below 100 °F (37.8 °C). Those with flash points above 100 °F and below 200 °F (93.3 °C) were classified as combustible liquids. Studies show that the actual measure of a liquid's flammability, its flash point, is dependent on altitude. Categorization Both OSHA and GHS further divide flammable liquids into 4 categories ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservation (library And Archival Science)
In library and archival science, preservation is a set of preventive conservation activities aimed at prolonging the life of a record, book, or object while making as few changes as possible. Preservation activities vary widely and may include monitoring the condition of items, maintaining the temperature and humidity in collection storage areas, writing a plan in case of emergencies, digitizing items, writing relevant metadata, and increasing accessibility. Preservation, in this definition, is practiced in a library or an archive by a librarian, archivist, or other professional when they perceive a record is in need of maintenance. Preservation should be distinguished from interventive conservation and restoration, which refers to the treatment and repair of individual items to slow the process of decay, or restore them to a usable state. Preventive conservation is occasionally used interchangeably with preservation, particularly outside the professional literature. Fundamenta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erasermate
Erasermate (known as the ''Replay'' in Europe and Brazil) is a pen product introduced by the Papermate division of the Gillette Company in 1979. The word Erasermate in and of itself has become known as the erasable pen of the Papermate product line. The original Erasermate pen was a refillable ballpoint pen fitted with a replaceable eraser. A disposable version called Erasermate 2 was subsequently introduced, with an appearance similar to the non-erasable Write Bros. stick pen, except for a slightly larger girth, and of course the black eraser, affixed to the pen's cap. The eraser, similar to that of a standard no. 2 pencil, was about 5 mm in diameter, and 10 mm in length. The eraser was held in place by the force exerted by the cylindrical abscess of the pen cap. The eraser could be removed, but replacing it required more effort. Erasermates come in blue, black and red ink, with the pen's exterior often matching the color of its ink. In 1979/80 Papermate introduced two retra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Handicraft
A handicraft, sometimes more precisely expressed as artisanal handicraft or handmade, is any of a wide variety of types of work where useful and decorative objects are made completely by one’s hand or by using only simple, non-automated related tools like scissors, carving implements, or hooks. It is a traditional main sector of craft making and applies to a wide range of creative and design activities that are related to making things with one's hands and skill, including work with textiles, moldable and rigid materials, paper, plant fibers,clay etc. One of the oldest handicraft is Dhokra; this is a sort of metal casting that has been used in India for over 4,000 years and is still used. In Iranian Baluchistan, women still make red ware hand-made pottery with dotted ornaments, much similar to the 5000-year-old pottery tradition of Kalpurgan, an archaeological site near the village. Usually, the term is applied to traditional techniques of creating items (whether for perso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copydex
Copydex is a common latex-based rubber cement in the UK. It can be easily recognised by its characteristic "fishy" odour. It has been owned since 1986 by Henkel. Uses Also known as "fishy glue" this contact adhesive is commonly used when sticking a variety of materials, such as paper, board, upholstery, and carpet. It is used widely by model makers as a "mask" to protect areas during airbrushing. It can be used as an alternative to Table Tennis glue. Copydex is also frequently used to apply false eyelashes in the theatre to make sure they stay on during entire performances. Composition Unlike many other rubber cements, it consists of latex dissolved in water. As such it is relatively non-toxic and so is frequently used in primary schools. It also contains ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-heptane
Heptane or ''n''-heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 point is 100% iso-octane). Octane number equates to the anti-knock qualities of a comparison mixture of heptane and isooctane which is expressed as the percentage of isooctane in heptane and is listed on pumps for gasoline (petrol) dispensed globally. Uses Heptane (and its many isomers) is widely used in laboratories as a non-polar solvent. As a liquid, it is ideal for transport and storage. In the grease spot test, heptane is used to dissolve an oil spot to show the previous presence of organic compounds on a stained paper. This is done by shaking the stained paper in a heptane solution for about half a minute. Aqueous bromine may be distinguished from aqueous iodine by its appearance after extraction into heptane. In water, both bromi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major industrial chemical, it finds limited use in consumer items because of its toxicity. History Discovery The word "''benzene''" derives from "''gum benzoin''" (benz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroform
Chloroform, or trichloromethane, is an organic compound with formula C H Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various refrigerants. It is trihalomethane. It is a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Structure The molecule adopts a tetrahedral molecular geometry with C3v symmetry. Natural occurrence The total global flux of chloroform through the environment is approximately tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil. Abiotic processes are also believed to contribute to natural chloroform productions in soils although the mechanism is still unclear. Chloroform volatilizes readily from soil and surface water and undergoes degradation in air to produce phosgene, dichloromethane, formyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gum Arabic
Gum arabic, also known as gum sudani, acacia gum, Arabic gum, gum acacia, acacia, Senegal gum, Indian gum, and by other names, is a natural gum originally consisting of the hardened sap of two species of the ''Acacia'' tree, '' Senegalia senegal'' and '' Vachellia seyal.'' The term "gum arabic" does not legally indicate a particular botanical source, however. The gum is harvested commercially from wild trees, mostly in Sudan (80%) and throughout the Sahel, from Senegal to Somalia. The name "gum Arabic" (''al-samgh al-'arabi'') was used in the Middle East at least as early as the 9th century. Gum arabic first found its way to Europe via Arabic ports, so retained its name. Gum arabic is a complex mixture of glycoproteins and polysaccharides, predominantly polymers of arabinose and galactose. It is soluble in water, edible, and used primarily in the food industry and soft-drink industry as a stabilizer, with E number E414 (I414 in the US). Gum arabic is a key ingredient in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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