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Zimmerit Tiger II 2 Bovington
''Zimmerit'' was a paste-like coating used on mid- and late-war German armored fighting vehicles during World War II. It was used to produce a hard layer covering the metal armor of the vehicle, providing enough separation that magnetically attached anti-tank mines would fail to stick to the vehicle, despite Germany being the only country to use magnetic anti-tank mines in numbers. ''Zimmerit'' was often left off late-war vehicles due to the unfounded concern that it could catch fire when hit. It was developed by the German company Chemische Werke Zimmer & Co (Berlin). Operation The coating was a barrier that prevented direct contact of magnetic mines with metal surfaces of vehicles. The magnetostatic field decreases very rapidly, with the cube of distance; the non-magnetic coating holds the magnet of the mine too far from the steel of the vehicle for it to adhere. The coating was normally ridged to increase the distance between the magnet and the armor even further, as the hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bundesarchiv Bild 101I-299-1802-08, Nordfrankreich, Michael Wittmann Auf Panzer VI (Tiger I)
, type = Archive , seal = , seal_size = , seal_caption = , seal_alt = , logo = Bundesarchiv-Logo.svg , logo_size = , logo_caption = , logo_alt = , image = Bundesarchiv Koblenz.jpg , image_caption = The Federal Archives in Koblenz , image_alt = , formed = , preceding1 = , preceding2 = , dissolved = , superseding1 = , superseding2 = , agency_type = , jurisdiction = , status = Active , headquarters = PotsdamerStraße156075Koblenz , coordinates = , motto = , employees = , budget = million () , chief1_name = Michael Hollmann , chief1_position = President of the Federal Archives , chief2_name = Dr. Andrea Hänger , chief2_position ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HEAT
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is also often used to refer to the thermal energy contained in a system as a component of its internal energy and that is reflected in the temperature of the system. For both uses of the term, heat is a form of energy. An example of formal vs. informal usage may be obtained from the right-hand photo, in which the metal bar is "conducting heat" from its hot end to its cold end, but if the metal bar is considered a thermodynamic system, then the energy flowing within the metal bar is called internal energy, not heat. The hot metal bar is also transferring heat to its surroundings, a correct statement for both the strict and loose meanings of ''heat''. Another example of informal usage is the term '' heat content'', used despite the fact that p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panzer III
The ''Panzerkampfwagen III'', commonly known as the Panzer III, was a medium tank developed in the 1930s by Germany, and was used extensively in World War II. The official German ordnance designation was Sd.Kfz. 141. It was intended to fight other armoured fighting vehicles and serve alongside and support the similar Panzer IV, which was originally designed for infantry support. However, as the Germans faced the formidable T-34, more powerful anti-tank guns were needed, and since the Panzer IV had more development potential with a larger turret ring, it was redesigned to mount the long-barrelled 7.5 cm KwK 40 gun. The Panzer III effectively swapped roles with the Panzer IV, as from 1942 the last version of the Panzer III mounted the 7.5 cm KwK 37 L/24 that was better suited for infantry support. Production of the Panzer III ceased in 1943. Nevertheless, the Panzer III's capable chassis provided hulls for the Sturmgeschütz III assault gun until the end of the war. Development h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major industrial chemical, it finds limited use in consumer items because of its toxicity. History Discovery The word "''benzene''" derives from "''gum benzoin''" (benzoin res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawdust
Sawdust (or wood dust) is a by-product or waste product of woodworking operations such as sawing, sanding, milling, planing, and routing. It is composed of small chippings of wood. These operations can be performed by woodworking machinery, portable power tools or by use of hand tools. Wood dust is also the byproduct of certain animals, birds and insects which live in wood, such as the woodpecker and carpenter ant. In some manufacturing industries it can be a significant fire hazard and source of occupational dust exposure. Sawdust, as particulates, is the main component of particleboard. Research on health hazards comes from the field of occupational safety and health, and study of ventilation happens in indoor air quality engineering. Formation Two waste products, dust and chips, form at the working surface during woodworking operations such as sawing, milling and sanding. These operations both shatter lignified wood cells and break out whole cells and groups of cells. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Sulfide
Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various impurities, the pure material is white, and it is widely used as a pigment. In its dense synthetic form, zinc sulfide can be transparent, and it is used as a window for visible optics and infrared optics. Structure ZnS exists in two main crystalline forms. This dualism is an example of polymorphism. In each form, the coordination geometry at Zn and S is tetrahedral. The more stable cubic form is known also as zinc blende or sphalerite. The hexagonal form is known as the mineral wurtzite, although it also can be produced synthetically.. The transition from the sphalerite form to the wurtzite form occurs at around 1020 °C. A tetragonal form is also known as the very rare mineral called polhemusite, with the formula . Applicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ochre
Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced by this pigment, especially a light brownish-yellow. A variant of ochre containing a large amount of hematite, or dehydrated iron oxide, has a reddish tint known as "red ochre" (or, in some dialects, ruddle). The word ochre also describes clays coloured with iron oxide derived during the extraction of tin and copper. Earth pigments Ochre is a family of earth pigments, which includes yellow ochre, red ochre, purple ochre, sienna, and umber. The major ingredient of all the ochres is iron(III) oxide-hydroxide, known as limonite, which gives them a yellow colour. * Yellow ochre, , is a hydrated iron hydroxide (limonite) also called gold ochre. * Red ochre, , takes its reddish colour from the mineral hematite, which is an anhydrous iron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compounds. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli. Economic impact In 2006, around 7.4 million tons of inorganic, organic, and special pigments were marketed worldwide. Estimated at around US$14.86 billion in 2018 and will rise at over 4.9% CAGR from 2019 to 2026. The global demand for pigments was roughly US$20.5 billion in 2009. According to an April 2018 report by ''Bloomberg Businessweek'', the estimated value of the pigment industry globally is $30 billion. The value of titanium dioxide – used to enhance the white brightness of many products – was placed at $13.2 billion per year, while the color Ferrari red is valued at $300 million each year. Physical principles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood Glue
Wood glue is an adhesive used to tightly bond pieces of wood together. Many substances have been used as glues. Types Animal glue Animal glue, especially hoof glue and hide glue, was the primary adhesive of choice for many types of woodworking, including furniture and lutherie, for many centuries. It is manufactured from rendered collagen from the skins (hides) or hooves of animals. It is chemically similar to edible gelatin and is non-toxic if ingested. Hide glue is still used today in specialized applications: musical instruments (lutherie), for replica furniture, and for conservation-grade repairs to antique woodwork. Hide glue is measured on the basis of its gel strength, a measure of how many grams of force it requires to depress a plunger into a 12.5% protein solution of the glue at . Glue is manufactured in standard grades from . strength is the most commonly used for woodworking; is the highest normally used for instrument building; is the lowest used for general w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyvinyl Acetate
Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue, PVA glue, white glue, carpenter's glue, school glue, or Elmer's glue in the US, is a widely available adhesive used for porous materials like wood, paper, and cloth. An aliphatic rubbery synthetic polymer with the formula (C4H6O2)''n'', it belongs to the polyvinyl ester family, with the general formula − COOCHCH2ˆ’. It is a type of thermoplastic. Properties The degree of polymerization of polyvinyl acetate is typically 100 to 5000, while its ester groups are sensitive to base hydrolysis and slowly convert PVAc into polyvinyl alcohol and acetic acid. The glass transition temperature of polyvinyl acetate is between 30 and 45 °C depending on the molecular weight. PVAc dispersions such as Elmer's Glue-All contain polyvinyl alcohol as a protective colloid. In alkaline conditions, boron compounds such as boric acid or borax cause the polyvinyl alcohol to cross-link, forming tackifying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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