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Emery (rock)
Emery, or corundite, is a dark granular rock used to make an abrasive powder. The rock largely consists of corundum (aluminium oxide), mixed with other minerals. Industrial emery may contain a variety of other minerals and synthetic compounds. Crushed or naturally eroded emery (known as ''black sand'') is used as an abrasive. Turkey and Greece are the main suppliers of the world's emery. Description Emery is a granular rock used to make an abrasive powder. It largely consists of corundum (aluminium oxide), mixed with other minerals such as the iron-bearing spinels, hercynite, and magnetite, and also rutile ( titania). Industrial emery may contain a variety of other minerals and synthetic compounds such as magnesia, mullite, and silica. Emery is black or dark grey in colour, less dense than translucent-brown corundum with a specific gravity of between 3.5 and 3.8. Because it can be a mixture of minerals, no definite Mohs hardness can be assigned: the hardness of corundum is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naxos Emery-mine
Naxos (; , ) is a Greek island belonging to the Cyclades island group. It is the largest island in the group. It was an important centre during the Bronze Age Cycladic Culture and in the Ancient Greek Archaic Period. The island is famous as a source of emery, a rock rich in corundum, which until modern times was one of the best abrasives available. The largest town and capital of the island is Chora or Naxos City, with 8,897 inhabitants (2021 census). The main villages are Filoti, Apiranthos, Vivlos, Agios Arsenios, Koronos and Glynado. History Mythic Naxos According to Greek mythology, the young Zeus was raised in a cave on Mt. Zas ("''Zas''" meaning "''Zeus''"). Homer mentions " Dia"; literally the sacred island "of the Goddess". Károly Kerényi explains: One legend has it that in the Heroic Age before the Trojan War, Theseus abandoned Ariadne on this island after she helped him kill the Minotaur and escape from the Labyrinth. Dionysus (god of wine, festivit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asphalt Concrete
Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and Tarmacadam, tarmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface road surface, roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the nineteenth century. It consists of Construction aggregate, mineral aggregate Binder (material), bound together with bitumen (a substance also independently known as asphalt, Pitch (resin), pitch, or tar), laid in layers, and compacted. The American English terms ''asphalt'' (or ''asphaltic'') ''concrete'', ''bituminous asphalt concrete'', and ''bituminous mixture'' are typically used only in engineering and construction documents, which define concrete as any composite material composed of mineral aggregate adhered with a binder. The abbreviation, ''AC'', is sometimes used for ''asphalt concrete'' but can also denot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Minerals
Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air. It visually resembles silver, both in its color and in its great ability to reflect light. It is soft, nonmagnetic, and ductile. It has one stable isotope, 27Al, which is highly abundant, making aluminium the 12th-most abundant element in the universe. The radioactivity of 26Al leads to it being used in radiometric dating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it has more polarizing power, and bonds formed by aluminium have a more covalent character. The s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machinery's Handbook
''Machinery's Handbook'' ''for machine shop and drafting-room; a reference book on machine design and shop practice for the mechanical engineer, draftsman, toolmaker, and machinist'' (the full title of the 1st edition) is a classic reference work in mechanical engineering and practical workshop mechanics in one volume published by Industrial Press, New York, since 1914. The first edition was created by Erik Oberg (1881–1951) and Franklin D. Jones (1879–1967), who are still mentioned on the title page of the 29th edition (2012). Recent editions of the handbook contain chapters on mathematics, mechanics, materials, measuring, toolmaking, manufacturing, threading, gears, and machine elements, combined with excerpts from ANSI standards. ''Machinery's Handbook'' is still regularly revised and updated; the most current revision is Edition 32 (2024). It continues to be the "bible of the metalworking industries" today. The work is available in online and ebook form as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emery Paper
upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)) Sandpaper, also known as coated abrasive or emery paper, is a type of material that consists of sheets of paper or cloth with an abrasive substance glued to one face. In the modern manufacture of these products, sand and glass have been replaced by other abrasives such as aluminium oxide or silicon carbide. It is common to use the name of the abrasive when describing the paper, e.g. "aluminium oxide paper", or "silicon carbide paper". There are many varieties of sandpaper, with variations in the paper or backing, the material used for the grit, grit size, and the bond. Sandpaper is produced in a range of grit sizes and is used to remove material from surfaces, whether to make them smoother (for example, in painting and wood finishing), to remove a layer of material (such as old paint), or sometimes to make the surface rougher (for example, as a preparation for gluing). The grit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permissible Exposure Limit
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agents such as high level noise. Permissible exposure limits were established by the Occupational Safety and Health Administration (OSHA). Most of OSHA's PELs were issued shortly after the adoption of the Occupational Safety and Health (OSH) Act in 1970. Chemical regulation is sometimes expressed in parts per million (ppm), but often in milligrams per cubic meter (mg/m3). Units of measure for physical agents such as noise are specific to the agent. A PEL is usually given as a time-weighted average (TWA), although some are short-term exposure limits (STEL) or ceiling limits. A TWA is the average exposure over a specified period, usually a nominal eight hours. This means that for limited periods, a worker may be exposed to concentration excursions higher than the PEL as long as the TWA is not exceeded and any applicable excursion l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occupational Safety And Health Administration
The Occupational Safety and Health Administration (OSHA; ) is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established the agency under the Occupational Safety and Health Act (OSH Act), which President Richard Nixon, Richard M. Nixon signed into law on December 29, 1970. OSHA's mission is to "assure safe and healthy working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education, and assistance." The agency is also charged with enforcing a variety of whistleblower statutes and regulations. OSHA's workplace safety inspections have been shown to reduce injury rates and injury costs without adverse effects on employment, sales, credit ratings, or firm survival. History The Bureau of Labor Standards of the Department of Labor has worked on some work safety issues since its creation in 1934. Economi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sintering
Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plastics, and other materials. The atoms/molecules in the sintered material diffuse across the boundaries of the particles, fusing the particles together and creating a solid piece. Since the sintering temperature does not have to reach the melting point of the material, sintering is often chosen as the shaping process for materials with extremely high melting points, such as tungsten and molybdenum. The study of sintering in metallurgy, metallurgical powder-related processes is known as powder metallurgy. An example of sintering can be observed when ice cubes in a glass of water adhere to each other, which is driven by the temperature difference between the water and the ice. Examples of pressure-driven sintering are the compacting of snowfa ... [...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] |
Pliny The Elder
Gaius Plinius Secundus (AD 23/24 79), known in English as Pliny the Elder ( ), was a Roman Empire, Roman author, Natural history, naturalist, and naval and army commander of the early Roman Empire, and a friend of the Roman emperor, emperor Vespasian. He wrote the encyclopedic (''Natural History''), a comprehensive thirty-seven-volume work covering a vast array of topics on human knowledge and the natural world, which became an editorial model for encyclopedias. He spent most of his spare time studying, writing, and investigating natural and geographic phenomena in the field. Among Pliny's greatest works was the twenty-volume ''Bella Germaniae'' ("The History of the German Wars"), which is Lost literary work, no longer extant. ''Bella Germaniae'', which began where Aufidius Bassus' ''Libri Belli Germanici'' ("The War with the Germans") left off, was used as a source by other prominent Roman historians, including Plutarch, Tacitus, and Suetonius. Tacitus may have used ''Bella Ger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naxos
Naxos (; , ) is a Greek island belonging to the Cyclades island group. It is the largest island in the group. It was an important centre during the Bronze Age Cycladic Culture and in the Ancient Greek Archaic Period. The island is famous as a source of emery, a rock rich in corundum, which until modern times was one of the best abrasives available. The largest town and capital of the island is Chora or Naxos City, with 8,897 inhabitants (2021 census). The main villages are Filoti, Apiranthos, Vivlos, Agios Arsenios, Koronos and Glynado. History Mythic Naxos According to Greek mythology, the young Zeus was raised in a cave on Mt. Zas ("''Zas''" meaning "''Zeus''"). Homer mentions " Dia"; literally the sacred island "of the Goddess". Károly Kerényi explains: One legend has it that in the Heroic Age before the Trojan War, Theseus abandoned Ariadne on this island after she helped him kill the Minotaur and escape from the Labyrinth. Dionysus (god of wine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Temple
Solomon's Temple, also known as the First Temple (), was a biblical Temple in Jerusalem believed to have existed between the 10th and 6th centuries BCE. Its description is largely based on narratives in the Hebrew Bible, in which it was commissioned by biblical king Solomon before being destroyed during the Siege of Jerusalem by Nebuchadnezzar II of the Neo-Babylonian Empire in 587 BCE. No excavations are allowed on the Temple Mount, and no positively identified remains of the destroyed temple have been found. Most modern scholars agree that the First Temple existed on the Temple Mount in Jerusalem by the time of the Babylonian siege, and there is significant debate among scholars over the date of its construction and the identity of its builder. The Hebrew Bible, specifically within the Book of Kings, includes a detailed narrative about the construction's ordering by Solomon, the penultimate ruler of the United Kingdom of Israel. It further credits Solomon as the placer of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
