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Maya Blue
Maya blue () is a unique bright turquoise or azure blue pigment manufactured by cultures of pre-Columbian Mesoamerica, such as the Mayas and Aztecs, during a period extending from approximately the 8th century to around 1860 CE. It is found in mural paintings on architectural buildings, ceramic pieces, sculptures, codices, and even in post-conquest Indochristian artworks and mural decorations. Manufacture The Maya blue pigment is a composite of organic and inorganic constituents, primarily indigo dyes derived from the leaves of anil (''Indigofera suffruticosa'', called ''ch'oj'' in Mayan) plants combined with palygorskite, a natural clay and type of fuller's earth. Palygorskite is most common in the Southern United States, but is not known to exist in abundant deposits in Mesoamerica.Arnold (2005); Haude (1997). Smaller trace amounts of other mineral additives have also been identified. Historical use Maya blue first appeared around 800, and it was still used in the 16th c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turquoise (color)
Turquoise ( ) is a cyan color, based on the turquoise, mineral of the same name. The word ''turquoise'' dates to the 17th century and is derived from the French language, French , meaning 'Turkish', because the mineral was first brought to Europe through Turkey from mines in the historical Greater Khorasan, Khorasan province of Iran (Persia) and Afghanistan today. The first recorded use of ''turquoise'' as a color name in English language, English was in 1573. The Web colors#X11 color names, X11 color named turquoise is displayed on the right. Turquoise gemstones Turquoise is an opaque, blue-to-green mineral that is a hydrate, hydrous phosphate of copper and aluminium, with the chemical formula copper, Cualuminium, Al6(phosphorus, Poxygen, O4)4(Ohydrogen, H)8·4water, H2O. It is rare and valuable in finer grades and has been prized as a gemstone, gem and ornamental stone for thousands of years owing to its unique hue. In many cultures of the Old world, Old and New Worlds, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitric Acid
Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water. When the solution contains more than 86% , it is referred to as ''fuming nitric acid''. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as red fuming nitric acid at concentrations above 86%, or white fuming nitric acid at concentrations above 95%. Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as synthetic dyes and medicines (e.g. metronidazole). Nitric acid is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francisco Hernández De Toledo
Francisco Hernández de Toledo (c. 1515 – 28 January 1587) was a naturalist and court physician to Philip II of Spain. He was among the first wave of Spanish Renaissance physicians practicing according to the revived principles formulated by Hippocrates, Galen and Avicenna. Francisco Hernández was born at La Puebla de Montalbán in the Province of Toledo, probably around 1515. Nothing is known of his parents or other family. His original surname was Fernando which he changed to Hernando in 1570 and then changed again to Hernández, the name he used until his death in 1587. In 1530 he began to study medicine at the University of Alcalá and received a bachelor's degree in 1536. After graduation, Hernández served as physician to the Duke of Maqueda in Toledo and later practiced medicine in Seville where he married Juana Díaz with whom he had two children, Juan Hernández and María of Sotomayor. From 1556 to 1560 Hernández served as a physician at the ''Hospital y Monasterio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernardino De Sahagún
Bernardino de Sahagún ( – 5 February 1590) was a Franciscan friar, missionary priest and pioneering ethnographer who participated in the Catholic evangelization of colonial New Spain (now Mexico). Born in Sahagún, Spain, in 1499, he journeyed to New Spain in 1529. He learned Nahuatl and spent more than 50 years in the study of Aztec beliefs, culture and history. Though he was primarily devoted to his missionary task, his extraordinary work documenting indigenous worldview and culture has earned him the title as "the first anthropologist."Arthur J.O. Anderson, "Sahagún: Career and Character" in Bernardino de Sahagún, ''Florentine Codex: The General History of the Things of New Spain, Introductions and Indices'', Arthur J.O. Anderson and Charles Dibble, translators. Salt Lake City: University of Utah Press 1982, p. 40.M. León-Portilla, Bernardino de Sahagún: The First Anthropologist' (University of Oklahoma Press, Norman, 2002), pp. He also contributed to the description ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montmorillonite
Montmorillonite is a very soft phyllosilicate group of minerals that form when they precipitate from water solution as microscopic crystals, known as clay. It is named after Montmorillon in France. Montmorillonite, a member of the smectite group, is a 2:1 clay, meaning that it has two tetrahedral sheets of silica sandwiching a central octahedral sheet of alumina. The particles are plate-shaped with an average diameter around 1 μm and a thickness of 0.96 nm; magnification of about 25,000 times, using an electron microscope, is required to resolve individual clay particles. Members of this group include saponite, nontronite, beidellite, and hectorite. Montmorillonite is a subclass of smectite, a 2:1 phyllosilicate mineral characterized as having greater than 50% octahedral charge; its cation exchange capacity is due to isomorphous substitution of Mg for Al in the central alumina plane. The substitution of lower valence cations in such instances leaves the nearby oxygen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constantino Reyes-Valerio
Constantino Reyes-Valerio (January 10, 1922, Zinacatepec, Puebla - December 13, 2006, Mexico City) was a prominent Mexican scholar of pre-Columbian Mesoamerican cultures, particularly the Aztec and the Maya as well as the Colonial Art. Life and career In 1947 he arrived in Mexico City, where five years later he obtained a Master's degree in Bacteriological Chemistry and Parasitology at the National Polytechnic Institute. Reyes-Valerio identified the artistic contribution of Native Mexican Indians in the Colonial painting and sculpture; he coined the term Indochristian art. Another major contribution was his seminal work on the chemical composition and process of the Maya Blue Pigment where he re-discovered the technique used by the Maya to create the famous turquoise blue pigment. He was granted a Guggenheim Fellowship in 1972 for Fine Arts Research. He corresponded extensively with major scholars in Mexico and abroad such as George Kubler, Santiago Sebastian and Enrique Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powder Diffraction
Powder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials. An instrument dedicated to performing such powder measurements is called a powder diffractometer. Powder diffraction stands in contrast to single crystal diffraction techniques, which work best with a single, well-ordered crystal. Explanation The most common type of powder diffraction is with X-rays, the focus of this article, although some aspects of neutron powder diffraction are mentioned. (Powder electron diffraction is more complex due to dynamical diffraction and is not discussed further herein.) Typical diffractometers use electromagnetic radiation (waves) with known wavelength and frequency, which is determined by their source. The source is often X-rays, and neutrons are also common sources, with their frequency determined by their de Broglie wavelength. When these waves reach the sample, the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mic Teotihuacan
Mic or MIC may refer to: * Microphone, an acoustic transducer Places * Federated States of Micronesia, UNDP country code * Miami Intermodal Center, a mega-transportation hub in Miami, Florida People * Mic (name), numerous people Arts, entertainment, and media * M.I.C. (band), a Chinese band formed by Taihe Rye Music * Mic (media company), a media company focused on news for millennials * Mic, an abbreviation for referencing the ''Book of Micah'' * ''Made in Chelsea'', a television series Organizations Business * Metal Improvement Company, a company specializing in metal surface treatments * Merida Industry Co., Ltd., a bicycle manufacturing company in Taiwan * Military Industries Corporation (Saudi Arabia), the main armament industry for the Saudi military * Military Industry Corporation, the main armament industry for the Sudanese military * Myanmar Investment Commission, a government-appointed body * Mortgage investment corporation, a Canadian investment and lending compan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleo-inspiration
Paleo-inspiration is a paradigm shift that leads scientists and designers to draw inspiration from ancient materials (from art, archaeology, natural history or paleo-environments) to develop new systems or processes, particularly with a view to sustainability. Paleo-inspiration has already contributed to numerous applications in fields as varied as green chemistry, the development of new artist materials, composite materials, microelectronics, and construction materials. Semantics and definitions While this type of application has been known for a long time, the concept itself was coined by teams from the French National Centre for Scientific Research, the Massachusetts Institute of Technology and the Bern University of Applied Sciences from the term Bioinspiration. They published the concept in a seminal paper published online in 2017 by the journal ''Angewandte Chemie''. Different names have been used to designate the corresponding systems, in particular: paleo-inspired, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflux
Reflux is a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations. It is also used in chemistry to supply energy to Chemical reaction, reactions over a long period of time. Reflux in industrial distillation The term ''reflux'' is very widely used in industries that utilize large-scale Fractionating column, distillation columns and Fractional distillation, fractionators such as oil refinery, petroleum refineries, petrochemical and chemical plants, and natural gas processing plants. In that context, reflux refers to the portion of the overhead liquid product from a distillation column or fractionator that is returned to the upper part of the column as shown in the schematic diagram of a typical industrial distillation column. Inside the column, the downflowing reflux liquid provides cooling and condensation of the upflowing vapors thereby increasing the effi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
