"century. Lead was removed from the composition in 1974, by BS5140, reinforced by the European directive BSEN611 in 1994. Until the end of the 18th century, the only method of manufacture was by casting and the soldering of components. From the last quarter of the 18th century, improvement in alloys (e.g. britannia metal) and techniques allowed objects to be made from pewter by stamping and spinning. English pewter While the term pewter covers a range of tin-based alloys, the term English pewter has come to represent a strictly-controlled alloy, specified by BSEN611-1 and British Standard 5140, consisting mainly of tin"
"check the purity of the gold in a crown, leading to the famous bath-house shouting of ""Eureka!"" upon the discovery of Archimedes' principle. The term pewter covers a variety of alloys consisting primarily of tin. As a pure metal, tin is much too soft to be used for any practical purpose. However, during the Bronze Age, tin was a rare metal in many parts of Europe and the Mediterranean; due to this it was often valued higher than gold. To make jewellery, cutlery, or other objects from tin, it was usually alloyed with other metals to increase its strength and"
"copper, and silica. Pewter was used for decorative metal items and tableware in the Ancient World by the Egyptians and later the Romans, and came into extensive use in Europe from the Middle Ages until the various developments in pottery and glass-making during the 18th and 19th centuries. Pewter was the chief material for producing plates, cups, and bowls until the making of porcelain. Mass production of pottery, porcelain and glass products has seen pewter universally replaced in daily life. Pewter artifacts continue to be produced, mainly as decorative or specialty items. Pewter was also used around East Asia. Although"
"hardness. These metals were typically lead, antimony, bismuth or copper. These solutes were sometimes added individually in varying amounts, or added together, making a wide variety of objects, ranging from practical items such as dishes, surgical tools, candlesticks or funnels, to decorative items like ear rings and hair clips. The earliest examples of pewter come from ancient Egypt, around 1450 BC. The use of pewter was widespread across Europe, from France to Norway and Britain (where most of the ancient tin was mined) to the Near East. The alloy was also used in China and the Far East, arriving in"
"be toxic. Tin in combination with other elements forms a wide variety of useful alloys. Tin is most commonly alloyed with copper. Pewter is 85–99% tin; bearing metal has a high percentage of tin as well. Bronze is mostly copper (12% tin), while addition of phosphorus gives phosphor bronze. Bell metal is also a copper–tin alloy, containing 22% tin. Tin has sometimes been used in coinage; for example, it once formed a single-digit percentage (usually five percent or less) of American and Canadian pennies. Because copper is often the major metal in such coins, sometimes including zinc, these could be"
"Pentaerythritol tetranitrate Pentaerythritol tetranitrate (PETN), also known as PENT, PENTA, TEN, corpent, or penthrite (or—rarely and primarily in German—as nitropenta), is an explosive material. It is the nitrate ester of pentaerythritol, and is structurally very similar to nitroglycerin. Penta refers to the five carbon atoms of the neopentane skeleton. PETN is a powerful explosive material with a relative effectiveness factor of 1.66. When mixed with a plasticizer, PETN forms a plastic explosive. Along with RDX it is the main ingredient of Semtex. PETN is also used as a vasodilator drug to treat certain heart conditions, such as for management of"
"Pterin Pterin is a heterocyclic compound composed of a pteridine ring system, with a ""keto group"" (a lactam) and an amino group on positions 4 and 2 respectively. It is structurally related to the parent bicyclic heterocycle called pteridine. Pterins, as a group, are compounds related to pterin with additional substituents. Pterin itself is of no biological significance. Pterins were first discovered in the pigments of butterfly wings (hence the origin of their name, from the Greek ""pteron (πτερόν)"", wing) and perform many roles in coloration in the biological world. One important family of pterin derivatives are Folates. Folates are"
"is also some evidence at Basta Voe in the north west of a more recent event of a similar nature. In modern times, the non-porous nature of the bedrock, the presence of boulder clay and the cool and damp climate have conspired to create large expanses of peat. This covers two thirds of the island with an average depth of . Its main constituent materials are sphagnum moss, cotton grass, deer grass, heather and sedge. This peat is highly important to the islanders as a fuel source, and in some areas is even worked commercially. It is cut with a"
"Pegmatites are important because they often contain rare earth minerals and gemstones, such as aquamarine, tourmaline, topaz, fluorite, apatite and corundum, often along with tin and tungsten minerals, among others. Pegmatites are the primary source of lithium either as spodumene, lithiophyllite or usually from lepidolite. The primary source for caesium is pollucite, a mineral from a zoned pegmatite. The majority of the world's beryllium is sourced from non-gem quality beryl within pegmatite. Tantalum, niobium, rare-earth elements are sourced from a few pegmatites worldwide, notably the Greenbushes Pegmatite. Bismuth, molybdenum and tin have been won from pegmatite, but this is not"
"Potassium nitrate Potassium nitrate is a chemical compound with the chemical formula KNO. It is an ionic salt of potassium ions K and nitrate ions NO, and is therefore an alkali metal nitrate. It occurs in nature as a mineral, niter. It is a source of nitrogen, from which it derives its name. Potassium nitrate is one of several nitrogen-containing compounds collectively referred to as saltpeter or saltpetre. Major uses of potassium nitrate are in fertilizers, tree stump removal, rocket propellants and fireworks. It is one of the major constituents of gunpowder (black powder) and has been used since the"
"Niter Niter, or nitre (chiefly British), is the mineral form of potassium nitrate, KNO, also known as saltpeter or saltpetre. Historically, the term ""niter"" was not well differentiated from natron, both of which have been very vaguely defined but generally refer to compounds of sodium or potassium joined with carbonate or nitrate ions. Related minerals are soda niter (sodium nitrate), ammonia niter or gwihabaite (ammonium nitrate), nitrostrontianite (strontium nitrate), nitrocalcite (calcium nitrate), nitromagnesite (magnesium nitrate), nitrobarite (barium nitrate) and two copper nitrates, gerhardtite and buttgenbachite; in fact all of the natural elements in the first three columns of the periodic"
"Nacre Nacre ( also ), also known as mother of pearl, is an organic-inorganic composite material produced by some molluscs as an inner shell layer; it also makes up the outer coating of pearls. It is strong, resilient, and iridescent. Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as ""flame structure"" as is found in conch pearls. The outer layer of pearls and"
"as a mosquito and insect repellent, likely due to essential oils in the leaves. Fresh leaves are used to scent laundry and hair. It is also grown as an ornamental plant. The main chemical compounds found in the essential oil of ""Plectranthus amboinicus"" are carvacrol (28.65%), thymol (21.66%), α-humulene (9.67%), undecanal (8.29%), γ-terpinene (7.76%), ""p""-cymene (6.46%), caryophyllene oxide (5.85%), α-terpineol (3.28%), and β-selinene (2.01%). Another analysis obtained thymol (41.3%), carvacrol (13.25%), 1,8-cineole (5.45%), eugenol (4.40%), caryophyllene (4.20%), terpinolene (3.75%), α-pinene (3.20%), β-pinene (2.50%), methyl eugenol (2.10%), and β-phellandrene (1.90%). The variations can be attributed to the methodology used in the"
"spherulite. Unlike metals, a spherulite cannot be described in terms of a lattice or unit cell, but rather as a set of polymer chains that pack down closely next to one another and form a dense core. The PP and PE components of a blend constitute the ""crystalline phase"", and the rubber gives the ""amorphous phase"". If PP and PE are the dominant component of a TPO blend then the rubber fraction will be dispersed into a continuous matrix of ""crystalline"" polypropylene. If the fraction of rubber is greater than 40% phase inversion may be possible when the blend cools,"
"made of FeO with PO making up almost the same weight percentage. There is a significant percentage of the NaO oxide and an insignificant percentage of the CaO oxide (~0). It is clear from looking at the oxide content of the mineral that the main components are going to be sodium, iron, phosphorus, and oxygen. The oxide factor may be used to determine the weight percentages of the individual elements as follows, 1 sodium atom totaling ~13% of composition, 1 iron atom totaling ~32% of composition, 1 phosphorus atom totaling ~18% of composition, and 4 oxygen atoms totaling ~37% of"
"Conservation and restoration of feathers The conservation and restoration of feathers can be a real challenge for conservators and requires knowledge of specialized care procedures and potential environmental problems like pests. -Feathers are made of a protein commonly found in the bodies of many animals known as keratin -Feathers take on a protective function -91% protein, 8% water, and 1% lipids -The most common types of feathers are contour and down Although there are many different parts to a feather, all of the parts fall into two subsections of the feather. The two main sections of the feather are the"
"and hydrophilicity. Teflon is a hydrophobic polymer composed of a carbon chain saturated with fluorine atoms. The fluorine-carbon bond is largely ionic, producing a strong dipole. The dipole prevents Teflon from being susceptible to Van der Waals forces, so other materials will not stick to the surface. Teflon is commonly used to reduce friction in biomaterial applications such as in arterial grafts, catheters, and guide wire coatings. PEEK is a semicrystalline polymer composed of benzene, ketone, and ether groups. PEEK is known for having good physical properties including high wear resistance and low moisture absorption and has been used for"
"in many organic compounds, both natural and synthetic (see figure). Most common among natural products is the amino acid phenylalanine, which contains a phenyl group. A major product of the petrochemical industry is ""BTX"" consisting of benzene, toluene, and xylene - all of which are building blocks for phenyl compounds. The polymer polystyrene is derived from a phenyl-containing monomer and owes its properties to the rigidity and hydrophobicity of the phenyl groups. Many drugs as well as many pollutants contain phenyl rings. One of the simplest phenyl-containing compounds is phenol, CHOH. It is often said the resonance stability of phenol"
"Conservation Institute examined the photograph using X-ray fluorescence spectroscopy, reflectance Fourier transform infrared spectroscopy, and other techniques. They confirmed that the image consists of bitumen and that the metal plate is pewter (tin alloyed with lead, as well as trace amounts of iron, copper, and nickel). The Institute also designed and built the elaborate display case system that now houses the artifact in a continuously monitored, stabilized, oxygen-free environment. In 2007, scientists from the Louvre Museum published an analysis of the photograph using ion beam analysis, with data taken on their 2 MV electrostatic accelerator. This showed the details of"
"Pentaerythritol Pentaerythritol is an organic compound, a white, crystalline solid with the formula CHO. It is a polyol with the neopentane backbone and one hydroxyl group in each of the four terminal carbons. It is a building block for the synthesis and production of explosives, plastics, paints, appliances, cosmetics, and many other important chemicals. The word pentaerythritol is a portmanteau of ""penta-"" in reference to the number of carbon atoms and ""erythritol"", which also possess 4 alcohol groups. Pentaerythritol was first synthesized in 1891 by German chemist Bernhard Tollens and his student P. Wigand. It may be prepared via a"
"ruby"", ""Elie Ruby"", ""Bohemian carbuncle"", and ""Cape ruby"". The composition of pure pyrope is MgAl(SiO), although typically other elements are present in at least minor proportions—these other elements include Ca, Cr, Fe and Mn. Pyrope forms a solid solution series with almandine and spessartine, which are collectively known as the ""pyralspite"" garnets (pyrope, almandine, spessartine). Iron and manganese substitute for the magnesium in the pyrope structure. The resultant, mixed composition garnets are defined according to their pyrope-almandine ratio. The semi-precious stone rhodolite is a garnet of ~70% pyrope composition. The origin of most pyrope is in ultramafic rocks, typically peridotite"
"a support. Unlike dentin and bone, enamel does not contain collagen. Proteins of note in the development of enamel are ameloblastins, amelogenins, enamelins and tuftelins. It is believed that they aid in the development of enamel by serving as framework support, among other functions. Dentin is the substance between enamel or cementum and the pulp chamber. It is secreted by the odontoblasts of the dental pulp. The formation of dentin is known as dentinogenesis. The porous, yellow-hued material is made up of 70% inorganic materials, 20% organic materials, and 10% water by weight. Because it is softer than enamel, it"
"27.17%, CaO to be 12.81%, PO to be 21.61%, leaving 24.69% to be determined as HO. The formula's essential elements are Al, Ca, H, O, P and Si with trace amounts of Sr. Common impurities of perhamite include Ti, Fe, Mg, Na, and F. Perhamite can range in color from white to brown and can be translucent to opaque. Its luster is said to be earthy, but vitreous to pearly along fractures. It occurs as radial discoidal, platy hexagonal crystals, in rough spherules up to 1mm thick. The specific gravity of perhamite is measured at 2.64 with a calculated density"
"Dentin Dentin () (American English) or dentine ( or ) (British English) () is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by enamel on the crown and cementum on the root and surrounds the entire pulp. By volume, 45% of dentin consists of the mineral hydroxylapatite, 33% is organic material, and 22% is water. Yellow in appearance, it greatly affects the color of a tooth due to the translucency of enamel. Dentin, which is less mineralized and less brittle than enamel,"
"peat moss, is one of the most common components in peat, although many other plants can contribute. Soils consisting primarily of peat are known as histosols. Peat forms in wetland conditions, where flooding obstructs the flow of oxygen from the atmosphere, slowing the rate of decomposition. Peatlands, particularly bogs, are the primary source of peat, although less-common wetlands including fens, pocosins, and peat swamp forests also deposit peat. Landscapes covered in peat are home to specific kinds of plants including ""Sphagnum"" moss, ericaceous shrubs, and sedges (see bog for more information on this aspect of peat). Because organic matter accumulates"
"a lesser extent (6,530 ppm) in ""Mentha"" × ""piperita"" subsp. ""nothosubsp. piperita"") and menthone. It is known to repel some pest insects, including mosquitos, and has uses in organic gardening. The chemical composition of the essential oil from peppermint (""Mentha"" x ""piperita"" L.) was analyzed by GC/FID and GC-MS. The main constituents were menthol (40.7%) and menthone (23.4%). Further components were (+/-)-menthyl acetate, 1,8-cineole, limonene, beta-pinene and beta-caryophyllene. Peppermint oil is under preliminary research for its potential as a short-term treatment for irritable bowel syndrome, and has supposed uses in traditional medicine for minor ailments. Peppermint oil and leaves have"
"Suberin Suberin, cutin and lignins are complex, higher plant epidermis and periderm cell-wall macromolecules, forming a protective barrier. Suberin, a complex polyester biopolymer, is lipophilic, and composed of long chain fatty acids called suberin acids, and glycerol. Suberins and lignins are considered covalently linked to lipids and carbohydrates, respectively, and lignin is covalently linked to suberin, and to a lesser extent, to cutin. Suberin is a major constituent of cork, and is named after the cork oak, ""Quercus suber"". Its main function is as a barrier to movement of water and solutes. Suberin is highly hydrophobic and a somewhat 'rubbery'"
"Pectin Pectin (from ', ""congealed, curdled"") is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. It was first isolated and described in 1825 by Henri Braconnot. It is produced commercially as a white to light brown powder, mainly extracted from citrus fruits, and is used in food as a gelling agent, particularly in jams and jellies. It is also used in dessert fillings, medicines, sweets, as a stabilizer in fruit juices and milk drinks, and as a source of dietary fiber. In plant biology, pectin consists of a complex set of polysaccharides (see below) that are"
"in the periodic table: iron (Fe), lithium (Li), and sodium (Na). Since iron is a predominant element in blood, lithium is sometimes used in methamphetamine production, and sodium is a component of tears, the title was interpreted by some as ""blood, meth and tears"". According to Eric Brown of ""International Business Times"": ""In its pure form ... methamphetamine is composed solely of carbon (C), hydrogen (H) and nitrogen (N), no lithium involved. However, there are multiple ways to synthesize meth from other ingredients, and several involve lithium. The Birch reduction, also called the ""Nazi method,"" mixes lithium and ammonia to"
"zircon and 3.3 million tonnes of rutile. Products & Markets The Moma mine produces three main products, Ilmenite, Zircon and Rutile. It is also currently developing plans to produce Monazite. Ilmenite is a common accessory mineral in igneous rocks, sediments, and sedimentary rocks in many parts of the world. Apollo astronauts found abundant ilmenite in lunar rocks and the lunar regolith. Ilmenite is a black iron-titanium oxide with a chemical composition of FeTiO3. Ilmenite is the primary ore of titanium, a metal needed to make a variety of high-performance alloys. Most of the ilmenite mined worldwide is used to manufacture"
"KREEP KREEP, an acronym built from the letters K (the atomic symbol for potassium), REE (rare-earth elements) and P (for phosphorus), is a geochemical component of some lunar impact breccia and basaltic rocks. Its most significant feature is somewhat enhanced concentration of a majority of so-called ""incompatible"" elements (those that are concentrated in the liquid phase during magma crystallization) and the heat-producing elements, namely radioactive uranium, thorium, and potassium (due to presence of the radioactive K). The typical composition of KREEP includes about one percent, by mass, of potassium and phosphorus oxides, 20 to 25 parts per million of rubidium,"
"Cutin Cutin is one of two waxy polymers that are the main components of the plant cuticle, which covers all aerial surfaces of plants. The other major cuticle polymer is cutan, which is much more readily preserved in the fossil record. Cutin consists of omega hydroxy acids and their derivatives, which are interlinked via ester bonds, forming a polyester polymer of indeterminate size. There are two major monomer families of cutin, the C16 and C18 families. The C16 family consists mainly of 16-hydroxy palmitic acid and 9,16- or 10,16-dihydroxypalmitic acid. The C18 family consists mainly of 18-hydroxy oleic acid, 9,10-epoxy-18-hydroxy"
"edible medical thenardite is used as a laxative and anti-inflammatory agent while powder thenardite is an ingredient of powdered laundry detergent. Procter & Gamble is a major buyer of powdered thenardite from the company, using it to make laundry detergent. Lumena China Lumena New Materials (commonly called Lumena) is a Chinese mining and manufacturing company primarily engaged in the production of polyphenylene sulfide (PPS), an industrial plastic. According to a market research report in 2016, the company is among the largest producers of PPS. Lumena mines the glauberite and associated class of minerals that is the raw ingredient used by"