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Spirit Duplicator
A spirit duplicator (also Rexograph and Ditto machine in North America, Banda machine and Fordigraph machine in the U.K. and Australia) is a printing method invented in 1923 by Wilhelm Ritzerfeld, which was used for most of the 20th century. The term "spirit duplicator" refers to the alcohols that were the principal solvents used in generating copies. Spirit duplicators were used mainly by schools, churches, clubs, and other small organizations, such as in the production of fanzines, because of the limited number of copies one could make from an original, along with the low cost (and corresponding low quality) of copying. The spirit duplicator coexisted alongside the mimeograph and the hectograph, devices with a similar purpose but different operation. History The spirit duplicator was invented in 1923 by Wilhelm Ritzerfeld. The best-known manufacturer in the United States and the world was Ditto Corporation of Illinois. Copiers in the United Kingdom were commonly manufact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duplicator
Duplication, duplicate, and duplicator may refer to: Biology and genetics * Gene duplication, a process which can result in free mutation * Chromosomal duplication, which can cause Bloom and Rett syndrome * Polyploidy, a phenomenon also known as ''ancient genome duplication'' * Enteric duplication cysts, certain portions of the gastrointestinal tract * Diprosopus, a form of cojoined twins also known as ''craniofacial duplication'' * Diphallia, a medical condition also known as ''penile duplication'' Computing * Duplicate code, a source code sequence that occurs more than once in a program * Duplicate characters in Unicode, pairs of single Unicode code points that are canonically equivalent. The reason for this are compatibility issues with legacy systems * Data redundancy, either wanted or unwanted (in which case one resorts to data deduplication) * Content copying through cut, copy, and paste * File copying Mathematics * Duplication, or doubling, multiplication by 2 * Dup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pastel (color)
Pastels or pastel colors belong to a pale family of colors, which, when described in the HSV color space, have high value and low or medium saturation. They are named after the artistic medium made from pigment and solid binding agents, similar to crayons. Pastel sticks historically had lower saturation than paints of the same pigment, hence the name of this color family. The colors of this family are usually described as soothing, calming, and nostalgic. They tend to lean towards ideas of simplicity and help to contrast against the bolder and brighter colors that trend in our world. They are integrated into interior design in many places, such as healthcare to help soothe anxiety, or in classrooms to help the mind focus. Pastel colors work to oppose the brighter, bolder colors that tend to be common in many other places. Pink, mauve, and baby blue are commonly used pastel colors, as are mint green, peach, periwinkle, lilac, and lavender.There are no official listing o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hectograph
The hectograph, gelatin duplicator or jellygraph is a printing process that involves transfer of an original, prepared with special inks, to a pan of gelatin or a gelatin pad pulled tight on a metal frame. While the original use of the technology has diminished, it has recently been revived for use in the art world. The hectograph has been modernized and made practical for anyone to use. Process The special aniline dyes for making the master image came in the form of ink or in pens, pencils, carbon paper, and even typewriter ribbon. Hectograph pencils and pens are sometimes still available. Various other inks have been found usable to varying degrees in the process; master sheets for spirit duplicators have also been pressed into service. Unlike a spirit duplicator master, a hectograph master is not a mirror image. Thus, when using a spirit duplicator master with a hectograph, one writes on the back of the purple sheet, using it like carbon paper to produce an image on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid-free Paper
Acid-free paper is paper that, if infused in water, yields a neutral or basic pH (7 or slightly greater). It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin- and sulfur-free. Acid-free paper addresses the problem of preserving documents and preserving artwork for long periods. Overview Paper made from wood-based pulp that has not had its lignin removed turns yellow, becomes brittle and deteriorates. When exposed to light and/or heat, the molecules in the acidic paper will break down faster. Acidic wood-pulp paper became commonplace in the late 19th century, and in the 1930s. William Barrow (a chemist and librarian) published a report about the deterioration of acidic paper in the libraries. For fear of the gradual disintegration of written materials, measures have since been taken to improve the quality of paper. During production, acid-free paper may be treated with a mild base (usually calcium or m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescent Lighting
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, to produce ultraviolet and make a phosphor coating in the lamp glow. Fluorescent lamps convert electrical energy into visible light much more efficiently than incandescent lamps, but are less efficient than most LED lamps. The typical luminous efficacy of fluorescent lamps is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output (e.g. the luminous efficacy of an incandescent lamp may only be 16 lm/W). Fluorescent lamp fixtures are more costly than incandescent lamps because, among other things, they require a ballast to regulate current through the lamp, but the initial cost is offset by a much lower running cost. Compact fluorescent lamps (CFL) made in the same sizes as incandescent lamp bulbs are used as an energy-saving altern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet Light
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. These int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archivist
An archivist is an information professional who assesses, collects, organizes, preserves, maintains control over, and provides access to records and archives determined to have long-term value. The records maintained by an archivist can consist of a variety of forms, including letters, diaries, logs, other personal documents, government documents, sound or picture recordings, digital files, or other physical objects. Description As Richard Pearce-Moses wrote: Determining what records have enduring value can be challenging. Archivists must also select records valuable enough to justify the costs of storage and preservation, plus the labor-intensive expenses of arrangement, description, and reference service. The theory and scholarly work underpinning archives practices is called archival science. The most common related occupations are librarians, museum curators, and records managers. The occupation of archivist is distinct from that of librarian. The two occupations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Point
The flash point of a material is the "lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture". The flash point is sometimes confused with the autoignition temperature, the temperature that causes spontaneous ignition. The fire point is the lowest temperature at which the vapors keep burning after the ignition source is removed. It is higher than the flash point, because at the flash point vapor may not be produced fast enough to sustain combustion. Neither flash point nor fire point depends directly on the ignition source temperature, but ignition source temperature is far higher than either the flash or fire point, and can increase the temperature of fuel above the usual ambient temperature to facilitate ignition. Fuels The flash point is a descriptive characteristic that is used to distinguish between flammable fuels, such as petrol (also known as g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichlorofluoromethane
Trichlorofluoromethane, also called freon-11, CFC-11, or R-11, is a chlorofluorocarbon (CFC). It is a colorless, faintly ethereal, and sweetish-smelling liquid that boils around room temperature. CFC-11 is a Class 1 ozone-depleting substance which damages Earth's protective stratospheric ozone layer. R-11 is not flammable at ambient temperature and pressure but it can become very combustible if heated and ignited by a strong ignition source. Historical use Trichlorofluoromethane was first widely used as a refrigerant. Because of its high boiling point compared to most refrigerants, it can be used in systems with a low operating pressure, making the mechanical design of such systems less demanding than that of higher-pressure refrigerants R-12 or R-22. Trichlorofluoromethane is used as a reference compound for fluorine-19 NMR studies. Trichlorofluoromethane was formerly used in the drinking bird novelty, largely because it has a boiling point of . The replacement, di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the pseudoelement symbol for ethyl group, ethyl. Ethanol is a Volatility (chemistry), volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. As a psychoactive depressant, it is the active ingredient in alcoholic beverages, and the second most consumed drug globally behind caffeine. Ethanol is naturally produced by the fermentation process of sugars by yeasts or via petrochemical processes such as ethylene hydration. Historically it was used as a general anesthetic, and has modern medical applications as an antiseptic, disinfectant, solvent for some medications, and antidote for methanol poisoning and ethylene glycol poisoning. It is used as a chemical solvent and in the Chemical synthesis, synthesis of orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a light, Volatility (chemistry), volatile, colorless and flammable liquid with a distinctive alcoholic odor similar to that of ethanol (potable alcohol), but is more acutely toxic than the latter. Methanol acquired the name wood alcohol because it was once produced through destructive distillation of wood. Today, methanol is mainly produced industrially by hydrogenation of carbon monoxide. Methanol consists of a methyl group linked to a polar hydroxyl group. With more than 20 million tons produced annually, it is used as a Precursor (chemistry), precursor to other commodity chemicals, including formaldehyde, acetic acid, methyl tert-butyl ether, methyl ''tert''-butyl ether, methyl benzoate, anisole, peroxyacids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mauveine
Mauveine, also known as aniline purple and Perkin's mauve, was one of the first synthetic dyes. It was discovered serendipitously by William Henry Perkin in 1856 while he was attempting to synthesise the phytochemical quinine for the treatment of malaria. It is also among the first chemical dyes to have been mass-produced. Chemistry Mauveine is a mixture of four related aromatic compounds differing in number and placement of methyl groups. Its organic synthesis involves dissolving aniline, ''p''-toluidine, and ''o''-toluidine in sulfuric acid and water in a roughly 1:1:2 ratio, then adding potassium dichromate. ''Mauveine A'' () incorporates 2 molecules of aniline, one of ''p''-toluidine, and one of ''o''-toluidine. ''Mauveine B'' () incorporates one molecule each of aniline, ''p''-toluidine, and two of ''o''-toluidine. In 1879, Perkin showed mauveine B related to safranines by oxidative/ reductive loss of the ''p''-tolyl group. In fact, safranine is a 2,8-dimethyl phena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
