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Flash Powder
Flash powder is a pyrotechnic composition, a mixture of an oxidizer and a metallic fuel, which burns quickly (deflagrates) and produces a loud noise, regardless of confinement in some formulations. It is widely used in theatrical and display pyrotechnics and consumer fireworks (namely firecrackers, professional salutes, and formerly in banned items such as cherry bombs and M-80s) and was once used for flashes in photography. Different varieties of flash powder are made from different compositions; most common are potassium perchlorate and aluminium powder. Early formulations used potassium chlorate instead of potassium perchlorate. Flash powder compositions are also used in military pyrotechnics when production of large amount of noise or light is required, e.g., stun grenades, battle simulator devices, and photoflash bombs. History Lycopodium powder is a yellow-tan dust-like powder historically used as a flash powder. Today, the principal use of the powder is to create ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrotechnic Composition
A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic reaction, exothermic chemical reactions. Pyrotechnic substances do not rely on oxygen from external sources to sustain the reaction. Types Basic types of pyrotechnic compositions are: * flash powder – burns very fast, produces explosions and/or bright flashes of light * gunpowder – burns slower than flash powder, produces large amount of gases * solid propellants – produce large amount of hot gases, used as sources of kinetic energy for rockets and projectiles * pyrotechnic initiators – produce large amount of heat, flames, and/or hot sparks, used to ignite other compositions * gas generators – produce large amount of gas, either high volume at short time (for actuators and ejection charges, often using solid propellants) or controlled flow rate (e.g. chemical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoflash Bomb
Flashbombs are loaded into a photo-reconnaissance Melsbroek, Belgium. c.1944 A photoflash bomb, or flash bomb, is bomb">explosive ordnance dropped by aircraft, usually military surveillance aircraft, designed to detonate Air burst">above ground to create an extremely bright flash of light. These bombs, which are capable of producing light at an intensity of up to hundreds of millions of candlepower, assist surveillance aircraft in taking nighttime Aerial photographic reconnaissance, aerial photos without the need to fly low to the ground which would make them vulnerable to possible enemy detection. Due to the advent of better nighttime optics, satellite imagery, and stealth aircraft, these bombs are no longer used by the military. Construction There were several models of photoflash bombs, but most had a similar construction and makeup. For example, the M23A1 was constructed of a cardboard tube, capped on both ends with metal "plugs." The tube was then filled with a flash po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoichiometric
Stoichiometry () is the relationships between the masses of reactants and products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total mass of products, so the relationship between reactants and products must form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of the products can be empirically determined, then the amount of the other reactants can also be calculated. This is illustrated in the image here, where the unbalanced equation is: : : However, the current equation is imbalanced. The reactants have 4 hydrogen and 2 oxygen atoms, while the product has 2 hydrogen and 3 oxygen. To balance the hydrogen, a coefficient of 2 is added to the product H2O, and to fix the imbalance of oxygen, it is also added ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimony Trisulfide
Antimony trisulfide () is found in nature as the crystalline mineral stibnite and the amorphous red mineral (actually a mineraloid) metastibnite. It is manufactured for use in safety matches, military ammunition, explosives and fireworks. It is also used as friction materials in break lining. It is very important critical primer material for military applications and tracer bullets. It also is used in the production of ruby-colored glass and in plastics as a flame retardant. Historically the stibnite form was used as a grey pigment in paintings produced in the 16th century. In 1817, the dye and fabric chemist, John Mercer discovered the non-stoichiometric compound Antimony Orange (approximate formula ), the first good orange pigment available for cotton fabric printing. Antimony trisulfide was also used as the image sensitive photoconductor in vidicon camera tubes. It is a semiconductor A semiconductor is a material with electrical conductivity between that of a conduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activation Energy
In the Arrhenius model of reaction rates, activation energy is the minimum amount of energy that must be available to reactants for a chemical reaction to occur. The activation energy (''E''a) of a reaction is measured in kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol). Activation energy can be thought of as a magnitude of the potential barrier (sometimes called the energy barrier) separating minima of the potential energy surface pertaining to the initial and final thermodynamic state. For a chemical reaction to proceed at a reasonable rate, the temperature of the system should be high enough such that there exists an appreciable number of molecules with translational energy equal to or greater than the activation energy. The term "activation energy" was introduced in 1889 by the Swedish scientist Svante Arrhenius. Other uses Although less commonly used, activation energy also applies to nuclear reactions and various other physical phenomena. Temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonate
A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group . The term is also used as a verb, to describe carbonation: the process of raising the concentrations of carbonate and bicarbonate ions in water to produce carbonated water and other carbonated beverageseither by the addition of carbon dioxide gas under pressure or by dissolving carbonate or bicarbonate salts into the water. In geology and mineralogy, the term "carbonate" can refer both to carbonate minerals and carbonate rock (which is made of chiefly carbonate minerals), and both are dominated by the carbonate ion, . Carbonate minerals are extremely varied and ubiquitous in chemically precipitated sedimentary rock. The most common are calcite or calcium carbonate, , the chief constituent of limestone (as well as the main component of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicarbonate
In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochemical role in the physiological pH buffering system. The term "bicarbonate" was coined in 1814 by the English chemist William Hyde Wollaston. The name lives on as a trivial name. Chemical properties The bicarbonate ion (hydrogencarbonate ion) is an anion with the empirical formula and a molecular mass of 61.01 daltons; it consists of one central carbon atom surrounded by three oxygen atoms in a trigonal planar arrangement, with a hydrogen atom attached to one of the oxygens. It is isoelectronic with nitric acid (). The bicarbonate ion carries a negative one formal charge and is an amphiprotic species which has both acidic and basic properties. It is both the conjugate base of carbonic acid (); and the conjugate acid of , t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Pot
Pyrotechnics is the science and craft of creating fireworks, but also includes safety matches, oxygen candles, explosive bolts (and other fasteners), parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. This trade relies upon self-contained and self-sustained exothermic chemical reactions to make heat, light, gas, smoke and/or sound. The name comes from the Greek words ''pyr'' (πυρ; 'fire') and ''technikós'' (τεχνικός; 'artistic'). Improper use of pyrotechnics could lead to pyrotechnic accidents. People responsible for the safe storage, handling, and functioning of pyrotechnic devices are known as pyrotechnicians. Proximate pyrotechnics Explosions, flashes, smoke, flames, fireworks and other pyrotechnic-driven effects used in the entertainment industry are referred to as proximate pyrotechnics. Proximate refers to the pyrotechnic device's location relative to an audience. In the majority of jurisdictions, special traini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrome Alum
Chrome alum or Chromium(III) potassium sulfate is the potassium double sulfate of chromium. Its chemical formula is KCr(SO4)2 and it is commonly found in its dodecahydrate form as KCr(SO4)2·12(H2O). It is used in leather tanning. Production and properties Chromium alum is produced from chromate salts or from ferrochromium alloys. Concentrated aqueous solutions of potassium dichromate can be reduced, usually with sulfur dioxide but also with alcohols or formaldehyde, in the presence of sulfuric acid at temperatures <40 °C. Alternatively and less commonly, ferrochromium alloys can be dissolved in sulfuric acid and, after precipitation of the ferrous sulfate, the chrome alum crystallizes upon addition of potassium sulfate. Chromium alum crystallizes in regular octahedra with flattened cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Special Effects
Special effects (often abbreviated as F/X or simply FX) are illusions or visual tricks used in the theatre, film, television, video game, amusement park and simulator industries to simulate the fictional events in a story or virtual world. It is sometimes abbreviated as SFX, but this may also refer to ''sound effects''. Special effects are traditionally divided into the categories of mechanical effects and optical effects. With the emergence of digital filmmaking a distinction between special effects and visual effects has grown, with the latter referring to digital post-production and optical effects, while "special effects" refers to mechanical effects. Mechanical effects (also called practical or physical effects) are usually accomplished during the live-action shooting. This includes the use of mechanised props, scenery, scale models, animatronics, pyrotechnics and atmospheric effects: creating physical wind, rain, fog, snow, clouds, making a car appear to drive by i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theater
Theatre or theater is a collaborative form of performing art that uses live performers, usually actors to present experiences of a real or imagined event before a live audience in a specific place, often a stage. The performers may communicate this experience to the audience through combinations of gesture, speech, song, music, and dance. It is the oldest form of drama, though live theatre has now been joined by modern recorded forms. Elements of art, such as painted scenery and stagecraft such as lighting are used to enhance the physicality, presence and immediacy of the experience. Places, normally buildings, where performances regularly take place are also called "theatres" (or "theaters"), as derived from the Ancient Greek θέατρον (théatron, "a place for viewing"), itself from θεάομαι (theáomai, "to see", "to watch", "to observe"). Modern Western theatre comes, in large measure, from the theatre of ancient Greece, from which it borrows technical termino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
