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Grog (clay)
Grog, also known as firesand and chamotte, is a raw material usually made from crushed and ground potsherds, reintroduced back into crude clay to temper it before making ceramic ware. It has a high percentage of silica and alumina. It is normally available as a powder or chippings, and is an important ingredient in Coade stone. Production It can be produced by firing selected fire clays to high temperature before grinding and screening to specific particle sizes. Another method makes it from pitchers. The particle size distribution is generally coarser in size than the other raw materials used to prepare clay bodies. It tends to be porous and have low density. Properties Grog is composed of 40% minimum alumina, 30% minimum silica, 4% maximum iron(III) oxide, up to 2% calcium oxide and magnesium oxide combined.. Its melting point is approximately . Its boiling point is over . Its water absorption is maximum 7%. Its thermal expansion coefficient is 5.2 mm/m and thermal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grog - Ground Potsherds
Grog is a term used for a variety of alcoholic beverages. The word originally referred to rum diluted with water (and later on long sea voyages, also added the juice of limes or lemons), which British Vice-Admiral Edward Vernon introduced into the naval squadron he commanded in the West Indies on 21 August 1740. Vernon wore a coat of grogram cloth and was nicknamed ''Old Grogram'' or ''Old Grog''. The ''Merriam–Webster Collegiate Dictionary'', which agrees with this story of the word's origin, states that the word ''grog'' was first used in this sense in 1770, though other sources cite 1749. In modern times, the term ''grog'' has had a variety of meanings in a number of different cultures, but is most commonly used in Australia and New Zealand where it is a slang word for alcohol. Origin and history Background During the early modern period (1500–1800), sailors required significant quantities of fresh water on extended voyages. Since desalinating sea water was not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronze Age
The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second principal period of the three-age system proposed in 1836 by Christian Jürgensen Thomsen for classifying and studying ancient societies and history. An ancient civilization is deemed to be part of the Bronze Age because it either produced bronze by smelting its own copper and alloying it with tin, arsenic, or other metals, or traded other items for bronze from production areas elsewhere. Bronze is harder and more durable than the other metals available at the time, allowing Bronze Age civilizations to gain a technological advantage. While terrestrial iron is naturally abundant, the higher temperature required for smelting, , in addition to the greater difficulty of working with the metal, placed it out of reach of common use until the end o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, and brick. The earliest ceramics made by humans were pottery objects (''pots,'' ''vessels or vases'') or figurines made from clay, either by itself or mixed with other materials like silica, hardened and sintered in fire. Later, ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, amorphous ceramic coatings on top of the crystalline ceramic substrates. Ceramics now include domestic, industrial and building products, as well as a wide range of materials developed for use in advanced ceramic engineering, such as in semiconductors. The word "'' ceramic''" comes from the Greek word (), "of pottery" or "for pottery", from (), "potter's clay, tile, pottery". The earliest kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeology
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscapes. Archaeology can be considered both a social science and a branch of the humanities. It is usually considered an independent academic discipline, but may also be classified as part of anthropology (in North America – the four-field approach), history or geography. Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades. Archaeology is distinct from palaeontology, which is the study of fossil remains. Archaeology is particularly important for learning about prehistoric societies, for which, by definition, there are no written records. Prehistory includes over 99% of the human past, from the Paleolithic until the adven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pizza Stone
A baking stone is a portable cooking surface used in baking. It may be made of ceramic, stone or, more recently, salt. Food is put on the stone, which is then placed in an oven, though sometimes the stone is heated first. Baking stones are used much like cookie sheets, but may absorb additional moisture for crispier food. A pizza stone is a baking stone designed for cooking pizza. Overview Due to the thermal mass of baking stones and the material's property as a poor heat conductor, food is less likely to burn when one uses a baking stone instead of metal or glass bakeware. Baking stones are a variation on hot stone cooking, which is one of the oldest cooking techniques known. Some cooks recommend sprinkling corn meal or flour on the baking stone to prevent the crust from sticking or using parchment paper atop the stone. Baking "stones" may be purchased as unglazed ceramic tiles, unglazed fired clay tiles and quarried tiles, from tile shops and hardware stores. To prevent fract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Europe
Southern Europe is the southern region of Europe. It is also known as Mediterranean Europe, as its geography is essentially marked by the Mediterranean Sea. Definitions of Southern Europe include some or all of these countries and regions: Albania, Andorra, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, East Thrace, Gibraltar, Greece, Italy, Kosovo, Malta, Moldova, Monaco, Montenegro, North Macedonia, Portugal, Romania, San Marino, Serbia, Slovenia, Southern France, Spain, and Vatican City (the Holy See). Southern Europe is focused on the three peninsulas located in the extreme south of the European continent. These are the Iberian Peninsula, the Apennine Peninsula, and the Balkan Peninsula. These three peninsulas are separated from the rest of Europe by towering mountain ranges, respectively by the Pyrenees, the Alps and the Balkan Mountains. The location of these peninsulas in the heart of the Mediterranean Sea, as well as their mountainous reliefs, provide them with very ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Europe
Central Europe is an area of Europe between Western Europe and Eastern Europe, based on a common History, historical, Society, social and cultural identity. The Thirty Years' War (1618–1648) between Catholic Church, Catholicism and Protestantism significantly shaped the area's history. The concept of "Central Europe" appeared in the 19th century. Central Europe comprised most of the territories of the Holy Roman Empire and those of the two neighboring kingdoms of Kingdom of Poland, Poland and Kingdom of Hungary, Hungary. Hungary and parts of Poland were later part of the Habsburg monarchy, which also significantly shaped the history of Central Europe. Unlike their Western European (Portugal, Spain et al.) and Eastern European (Russia) counterparts, the Central European nations never had any notable Colony, colonies (either overseas or adjacent) due to their inland location and other factors. It has often been argued that one of the contributing causes of both World War I and Wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schist
Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes or plates. This texture (geology), texture reflects a high content of platy minerals, such as micas, talc, chlorite group, chlorite, or graphite. These are often interleaved with more granular minerals, such as feldspar or quartz. Schist typically forms during regional metamorphism accompanying the process of mountain building (orogeny) and usually reflects a medium Metamorphism#Metamorphic grades, grade of metamorphism. Schist can form from many different kinds of rocks, including sedimentary rocks such as mudstones and igneous rocks such as tuffs. Schist metamorphosed from mudstone is particularly common and is often very rich in mica (a ''mica schist''). Where the type of the original rock (the protolith) is discernible, the schist is us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Shock
Thermal shock is a type of rapidly transient mechanical load. By definition, it is a mechanical load caused by a rapid change of temperature of a certain point. It can be also extended to the case of a thermal gradient, which makes different parts of an object expand by different amounts. This differential expansion can be more directly understood in terms of strain, than in terms of stress, as it is shown in the following. At some point, this stress can exceed the tensile strength of the material, causing a crack to form. If nothing stops this crack from propagating through the material, it will cause the object's structure to fail. Failure due to thermal shock can be prevented by: # Reducing the thermal gradient seen by the object, by changing its temperature more slowly or increasing the material's thermal conductivity # Reducing the material's coefficient of thermal expansion # Increasing its strength # Introducing built-in compressive stress, as for example in tempered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesh (scale)
Mesh is a measurement of particle size often used in determining the particle-size distribution of a granular material. For example, a sample from a truckload of peanuts may be placed atop a mesh with 5 mm openings. When the mesh is shaken, small broken pieces and dust pass through the mesh while whole peanuts are retained on the mesh. A commercial peanut buyer might use a test like this to determine if a batch of peanuts has too many broken pieces. This type of test is common in some industries, and, to facilitate uniform testing methods, several standardized mesh series have been established. Metal surfaces mechanically polished are designated as having a mechanical finish related to the abrasive used. Many mesh sizes were historically given in the number of holes per inch; due to the width of the wires in the mesh, mesh numbers did not correspond directly to fractional inch sizes, and several different systems standardized with slightly different mesh sizes for the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamination
Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materials, such as plastic. A laminate is a permanently assembled object created using heat, pressure, welding, or adhesives. Various coating machines, machine presses and calendering equipment are used. Materials There are different lamination processes, depending primarily on the type or types of materials to be laminated. The materials used in laminates can be identical or different, depending on the process and the object to be laminated. Textile Laminated fabric are widely used in different fields of human activity, including medical and military. Woven fabrics (organic and inorganic based) are usually laminated by different chemical polymers to give them useful properties like chemical resistance, dust, grease, windproofness, photolumin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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