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Chrome Yellow
__NOTOC__ Chrome yellow is a yellow pigment in paints using monoclinic lead(II) chromate (PbCrO4). It occurs naturally as the mineral crocoite but the mineral ore itself was never used as a pigment for paint. After the French chemist Louis Vauquelin discovered the new element chromium in 1797 lead chromate was synthesized in the laboratory and used as a pigment beginning in the second decade of the nineteenth century. Chrome yellow had been commonly made by mixing solutions of lead nitrate and potassium chromate and filtering off the lead chromate precipitate. The pigment tends to react with hydrogen sulfide and darken on exposure to air over time, forming lead sulfide, and it contains the toxic heavy metal lead plus the toxic, carcinogenic chromate. For these reasons, it was replaced by another pigment, cadmium yellow (mixed with enough cadmium orange to produce a color equivalent to chrome yellow). Darkening may also occur from reduction by sulfur dioxide. Good quality ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Chromate
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromate Ion
Chromate salts contain the chromate anion, . Dichromate salts contain the dichromate anion, . They are oxyanions of chromium in the +6 oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible. Chemical properties Potassium-chromate-sample.jpg, potassium chromate Potassium-dichromate-sample.jpg, potassium dichromate Chromates react with hydrogen peroxide, giving products in which peroxide, , replaces one or more oxygen atoms. In acid solution the unstable blue peroxo complex Chromium(VI) oxide peroxide, CrO(O2)2, is formed; it is an uncharged covalent molecule, which may be extracted into ether. Addition of pyridine results in the formation of the more stable complex CrO(O2)2py. Acid–base properties In aqueous solution, chromate and dichromate anions exist in a chemical equilibrium. :2 + 2 H+ + H2O The predominance diagram shows that the position of the equilibrium depends on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holden HQ
The Holden HQ series is a range of automobiles that was produced by Holden in Australia from 1971 to 1974. The HQ was released on 15 July 1971, replacing the Holden HG series. It was the first ground-up redesign of the Holden line since its original release in 1948, and included an all-new body, chassis, and suspension. The HQ was later developed into a series of successor models, finally ending production when the WB series was discontinued in 1984. Model range The mainstream HQ passenger car range consisted of four-door sedan and five-door station wagon models in three trim levels. * Holden Belmont sedan * Holden Kingswood sedan * Holden Premier sedan * Holden Belmont station wagon * Holden Kingswood station wagon * Holden Premier station wagon The long wheelbase luxury model, "Statesman by GMH" consisted of one body style (four-door sedan) and was available in two trim levels. * Statesman * Statesman Deville A Holden SS sedan was released in August 1972. Although market ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock Haven, Pennsylvania
Lock Haven is the county seat of Clinton County, in the U.S. state of Pennsylvania. Located near the confluence of the West Branch Susquehanna River and Bald Eagle Creek, it is the principal city of the Lock Haven Micropolitan Statistical Area, itself part of the Williamsport–Lock Haven combined statistical area. At the 2010 census, Lock Haven's population was 9,772. Built on a site long favored by pre-Columbian peoples, Lock Haven began in 1833 as a timber town and a haven for loggers, boatmen, and other travelers on the river or the West Branch Canal. Resource extraction and efficient transportation financed much of the city's growth through the end of the 19th century. In the 20th century, a light-aircraft factory, a college, and a paper mill, along with many smaller enterprises, drove the economy. Frequent floods, especially in 1972, damaged local industry and led to a high rate of unemployment in the 1980s. The city has three sites on the National Register o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piper J-3
The Piper J-3 Cub is an American light aircraft that was built between 1938 and 1947 by Piper Aircraft. The aircraft has a simple, lightweight design which gives it good low-speed handling properties and short-field performance. The Cub is Piper Aircraft's most-produced model, with nearly 20,000 built in the United States. Its simplicity, affordability and popularity invokes comparisons to the Ford Model T automobile. The aircraft is a high-wing, strut-braced monoplane with a large-area rectangular wing. It is most often powered by an air-cooled, flat-4 piston engine driving a fixed-pitch propeller. Its fuselage is a welded steel frame covered in fabric, seating two people in tandem. The Cub was designed as a trainer. It had great popularity in this role and as a general aviation aircraft. Due to its performance, it was well suited for a variety of military uses such as reconnaissance, liaison and ground control. It was produced in large numbers during World War II as the L- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Color
A set (mathematics), set of primary colors or primary colours (see American and British English spelling differences#-our, -or, spelling differences) consists of colorants or colored lights that can be mixed in varying amounts to produce a gamut of colors. This is the essential method used to create the perception of a broad range of colors in, e.g., electronic displays, color printing, and paintings. Perceptions associated with a given combination of primary colors can be predicted by an appropriate mixing model (e.g., additive mixing, additive, subtractive mixing, subtractive) that reflects the physics of how light interacts with physical media, and ultimately the retina. Primary colors can also be conceptual (not necessarily real), either as additive mathematical elements of a color space or as irreducible phenomenological categories in domains such as psychology and Philosophy of color, philosophy. Color space primaries are precisely defined and empirically rooted in psychop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vincent Van Gogh
Vincent Willem van Gogh (; 30 March 185329 July 1890) was a Dutch Post-Impressionism, Post-Impressionist painter who posthumously became one of the most famous and influential figures in Western art history. In a decade, he created about 2,100 artworks, including around 860 oil paintings, most of which date from the last two years of his life. They include Trees and Undergrowth (Van Gogh series), landscapes, Still life paintings by Vincent van Gogh (Paris), still lifes, Portraits by Vincent van Gogh, portraits and Portraits of Vincent van Gogh, self-portraits, and are characterised by bold colours and dramatic, impulsive and expressive paintwork, brushwork that contributed to the foundations of modern art. Not commercially successful, he struggled with severe depression and poverty, eventually leading to his suicide at age thirty-seven. Born into an upper-middle class family, Van Gogh drew as a child and was serious, quiet, and thoughtful. As a young man, he worked as an ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avant-garde
The avant-garde (; In 'advance guard' or ' vanguard', literally 'fore-guard') is a person or work that is experimental, radical, or unorthodox with respect to art, culture, or society.John Picchione, The New Avant-garde in Italy: Theoretical Debate and Poetic Practices' (Toronto: University of Toronto Press, 2004), p. 64 . It is frequently characterized by aesthetic innovation and initial unacceptability.Kostelanetz, Richard, ''A Dictionary of the Avant-Gardes'', Routledge, May 13, 2013 The avant-garde pushes the boundaries of what is accepted as the norm or the '' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Term
A color term (or color name) is a word or phrase that refers to a specific color. The color term may refer to human perception of that color (which is affected by visual context) which is usually defined according to the Munsell color system, or to an underlying physical property (such as a specific wavelength of visible light). There are also numerical systems of color specification, referred to as color spaces. An important distinction must be established between color and shape, as these two attributes usually are used in conjunction with one another when describing in language. For example, they are labeled as alternative parts of speech terms color term and shape term. Psychological conditions for recognition of colors exist, such as those who cannot discern colors in general or those who see colors as sound (a variety of synesthesia). Color dimensions Typical human color vision is trichromatic, meaning it is based on a three-dimensional color gamut. These three dimensio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Nicolas Vauquelin
Prof. Louis Nicolas Vauquelin Royal Society of London, FRS(For) HFRSE (16 May 1763 – 14 November 1829) was a French pharmacist and chemist. He was the discoverer of both chromium and beryllium. Early life Vauquelin was born at Saint-André-d'Hébertot in Normandy, France, the son of Nicolas Vauquelin, an estate manager, and his wife, Catherine Le Charterier. His first acquaintance with chemistry was gained as laboratory assistant to an apothecary in Rouen (1777–1779), and after various vicissitudes he obtained an introduction to Antoine François, comte de Fourcroy, A. F. Fourcroy, in whose laboratory he was an assistant from 1783 to 1791. Moving to Paris, he became a laboratory assistant at the Jardin du Roi and was befriended by a professor of chemistry. In 1791 he was made a member of the Academy of Sciences and from that time he helped to edit the journal ''Annales de Chimie'' ''(Chemical annals)'', although he left the country for a while during the height of the French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laidlaw School Bus
Laidlaw (), organized as Laidlaw International, Inc. (with corporate headquarters in Naperville, Illinois) was the largest provider of intercity bus services, contract public transit and paratransit, and contract school bus service in both the United States and Canada. In February 2007, FirstGroup, a bus and rail transportation operator in the United Kingdom with subsidiaries in North America, acquired Laidlaw International, Inc. FirstGroup completed the acquisition of Laidlaw International on October 1, 2007, and rebranded Laidlaw services under the First umbrella. The deal combined North America’s two largest private school bus operators—Education Services and First Student Inc.—giving them a combined 40% of the school bus contractor market. Laidlaw had grown primarily through acquisitions of other companies and contracting of services formerly directly provided by government entities. It was the parent company of Laidlaw Transit (which was merged into First Transit) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coating
A coating is a covering that is applied to the surface of an object, usually referred to as the Substrate (materials science), substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquids, gases or solids e.g. Powder coatings. Paints and lacquers are coatings that mostly have dual uses of protecting the substrate and being decorative, although some artists paints are only for decoration, and the paint on large industrial pipes is for preventing corrosion and identification e.g. blue for process water, red for fire-fighting control etc. Functional coatings may be applied to change the surface properties of the substrate, such as adhesion, Wetting, wettability, corrosion resistance, or wear resistance. In other cases, e.g. semiconductor device fabrication (where the substrate is a wafer (electronics), wafer), the coating adds a completely new property, such as a magnetic response or electrical conductivity, and forms an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
