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Whetstone (tool)
Sharpening stones, or whetstones, are used to sharpen the edges of steel tools such as knives through grinding and honing. Such stones come in a wide range of shapes, sizes, and material compositions. They may be flat, for working flat edges, or shaped for more complex edges, such as those associated with some wood carving or woodturning tools. They may be composed of natural quarried material or from man-made material. They come in various grades, which refer to the grit size of the abrasive particles in the stone. (Grit size is given as a number, which indicates the spatial density of the particles; a higher number denotes a higher density and therefore smaller particles, which give a finer finish to the surface of the sharpened object.) Stones intended for use on a workbench are called bench stones, while small, portable ones, whose size makes it hard to draw large blades uniformly over them, especially "in the field", are called pocket stones. Often whetstones are used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whetstone Knife Sharpening, 2015-(01)
Whetstone may refer to: Tools and technology * Whetstone, a sharpening stone used for knives and other cutting tools * Hornfels, a type of stone sometimes called whetstone * Whetstone (benchmark), a benchmark for measuring computing power * Operation Whetstone, a nuclear test program in the 1960s Places United Kingdom * Whetstone, Leicestershire, a village and civil parish * Whetstone, London * Whetstones (stone circle), an ancient pagan monument in Powys, Wales United States * Whetstone, Arizona, a census-designated place * Whetstone, West Virginia, an unincorporated community * The Whetstone River in South Dakota and Minnesota * Whetstone Gulf State Park in New York * Whetstone High School (Columbus, Ohio), a high school located in the Clintonville neighborhood of Columbus, Ohio * Whetstone Mountain in Colorado * Whetstone Mountains in Arizona Other uses * Whetstone (surname) See also * Wheatstone (other) {{disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural History (Pliny)
The ''Natural History'' () is a Latin work by Pliny the Elder. The largest single work to have survived from the Roman Empire to the modern day, the ''Natural History'' compiles information gleaned from other ancient authors. Despite the work's title, its subject area is not limited to what is today understood by natural history; Pliny himself defines his scope as "the natural world, or life". It is encyclopedic in scope, but its structure is not like that of a modern encyclopedia. It is the only work by Pliny to have survived, and the last that he published. He published the first 10 books in AD 77, but had not made a final revision of the remainder at the time of Pliny the Elder#Death, his death during the Eruption of Mount Vesuvius in 79 AD, AD 79 eruption of Vesuvius. The rest was published posthumously by Pliny's nephew, Pliny the Younger. The work is divided into 37 books, organised into 10 volumes. These cover topics including astronomy, mathematics, geography, ethn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay Mineral
Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay minerals form in the presence of water and have been important to life, and many theories of abiogenesis involve them. They are important constituents of soils, and have been useful to humans since ancient times in agriculture and manufacturing. Properties Clay is a very fine-grained geologic material that develops plasticity when wet, but becomes hard, brittle and non–plastic upon drying or firing. It is a very common material, and is the oldest known ceramic. Prehistoric humans discovered the useful properties of clay and used it for making pottery. The chemistry of clay, including its capacity to retain nutrient cations such as potassium and ammonium, is important to soil fertility. Because the individual particles in clay are less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterstones
Waterstones Booksellers Limited, trading as Waterstones (formerly Waterstone's), is a British bookselling, book retailer based in London, England, owned by the American investment group Elliott Investment Management. It operates 311 shops, mainly in the United Kingdom and other nearby countries. it employed around 3,500 staff in Britain and Europe. The average Waterstones branch sells a range of approximately 30,000 individual books, as well as stationery and other related products. Founded in 1982 by Tim Waterstone, the bookseller expanded rapidly until being sold in 1993 to WHSmith. In 1998 Waterstones was bought by a consortium of Waterstone, EMI, and Advent International. The company was taken under the umbrella of HMV, which later merged the Dillons the Bookstore, Dillons and Ottakar's brands into the company. Following several poor sets of results for the group, HMV put the chain up for sale. In May 2011 it was announced that A&NN Capital Fund Management, owned by the R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kyoto
Kyoto ( or ; Japanese language, Japanese: , ''Kyōto'' ), officially , is the capital city of Kyoto Prefecture in the Kansai region of Japan's largest and most populous island of Honshu. , the city had a population of 1.46 million, making it the List of cities in Japan, ninth-most populous city in Japan. More than half (56.8%) of Kyoto Prefecture's population resides in the city. The city is the cultural anchor of the substantially larger Greater Kyoto, a metropolitan statistical area (MSA) home to a census-estimated 3.8 million people. It is also part of the even larger Keihanshin, Keihanshin metropolitan area, along with Osaka and Kobe. Kyoto is one of the oldest municipalities in Japan, having been chosen in 794 as the new seat of Japan's imperial court by Emperor Kanmu. The original city, named Heian-kyō, was arranged in accordance with traditional Chinese feng shui following the model of the ancient Chinese capitals of Chang'an and Luoyang. The emperors of Japan ruled fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Synthesis
Chemical synthesis (chemical combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as '' reagents'' or ''reactants'') that will experience a transformation under certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as a chemical reactor or a simple round-bottom flask. Many reactions require some form of processing (" work-up") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the '' reaction yield''. Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that could be produced based ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron Nitride
Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula B N. It exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form corresponding to graphite is the most stable and soft among BN polymorphs, and is therefore used as a lubricant and an additive to cosmetic products. The cubic ( zincblende aka sphalerite structure) variety analogous to diamond is called c-BN; it is softer than diamond, but its thermal and chemical stability is superior. The rare wurtzite BN modification is similar to lonsdaleite but slightly softer than the cubic form. Because of excellent thermal and chemical stability, boron nitride ceramics are used in high-temperature equipment and metal casting. Boron nitride has potential use in nanotechnology. History Boron nitride was discovered by chemistry teacher of the Liverpool Institute in 1842 via reduction of boric acid with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Oxide
Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several Aluminium oxide (compounds), aluminium oxides, and specifically identified as aluminium oxide. It is commonly called alumina and may also be called aloxide, aloxite, ALOX or alundum in various forms and applications and alumina is refined from bauxite. It occurs naturally in its crystalline Polymorphism (materials science), polymorphic phase (matter), phase α-Al2O3 as the mineral corundum, varieties of which form the precious gemstones ruby and sapphire,which have an alumina content approaching 100%. Al2O3 is used as feedstock to produce aluminium metal, as an abrasive owing to its hardness, and as a refractory material owing to its high melting point. Natural occurrence Corundum is the most common naturally occurring crystallinity, crystalline form of aluminium oxide. ruby, Rubies and sapphires are gem-quality forms o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Carbide
Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A wide bandgap semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and Cat's whisker detector, detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Natural occurrence Naturally occurring moissanite is found ... [...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 fired clay bricks used for building house walls and other structures. Other pottery objects such as pots, vessels, vases and figurines were made from clay, either by itself or mixed with other materials like silica, hardened by sintering 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 semiconductors. The word '' ceramic'' comes from the Ancient Greek word (), meaning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflective surface, the process can also involve roughening as in satin, matte or beaded finishes. In short, the ceramics which are used to cut, grind and polish other softer materials are known as abrasives. Abrasives are extremely commonplace and are used very extensively in a wide variety of industrial, domestic, and technological applications. This gives rise to a large variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Some common uses for abrasives include grinding, polishing, buffing, honing, cutting, drilling, sharpening, lapping, and sanding (see abrasive machining). (For simplicity, "mineral" in this article will be used loosely to refer to both minerals and mineral-like substances ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quern-stone
A quern-stone is a stone tool for hand-grinding a wide variety of materials, especially for various types of grains. They are used in pairs. The lower stationary stone of early examples is called a ''saddle quern'', while the upper mobile stone is called a ''muller'', ''rubber'', or ''handstone''. The upper stone was moved in a back-and-forth motion across the saddle quern. Later querns are known as ''rotary querns''. The central hole of a rotary quern is called the ''eye'', and a dish in the upper surface is known as the ''hopper''. A ''handle slot'' contained a handle which enabled the rotary quern to be rotated. They were first used in the Neolithic era to grind cereals into flour. Design The upper stones were usually concave while the lower ones were convex. Quern-stones are frequently identifiable by their grooved working surfaces which enabled the movement of flour. Sometimes a millrind was present as a piece of wood (or other material), which allowed the cereal et ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
