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Magnesium Torch
A magnesium torch is a bright light source made from magnesium, which can burn underwater and in all weather conditions. They are used for emergency illumination for railroad applications. They were also popular in the 1950s as a light source for scuba diving, and were featured occasionally in the ''Sea Hunt'' television show. A relay of magnesium torches was used to transfer the Olympic flame from Greece to the site of the Olympic games several times since the first occasion at the 1936 Berlin Games. Function Magnesium is highly flammable, burning at a temperature of approximately , and the autoignition temperature of magnesium ribbon is approximately . It produces intense, bright, white light when it burns. Once ignited, magnesium fires are difficult to extinguish, because combustion continues in nitrogen (forming magnesium nitride), carbon dioxide (forming magnesium oxide and carbon), and water (forming magnesium oxide and hydrogen). Structure Details may vary depending on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic table) it occurs naturally only in combination with other elements and it almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. It is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium. In the cosmos, magnesium is produced in large, aging stars by the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of the magnesium is expelled into the interstellar medium where it ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scuba Diving
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply. The name "scuba", an acronym for "Self-Contained Underwater Breathing Apparatus", was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long and/or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the likelihood and effects of nitrogen narcosis during deeper dives. Open circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Hunt
''Sea Hunt'' is an American action adventure television series that aired in syndication from 1958 to 1961 and was popular for decades afterwards. The series originally aired for four seasons, with 155 episodes produced. It stars Lloyd Bridges as former Navy diver Mike Nelson, and was produced by Ivan Tors. Development Series executive producer Ivan Tors conceived the idea for ''Sea Hunt'' while working on the 1958 film ''Underwater Warrior''. He tried in vain to sell the series to all three major networks, but each network passed on it because they felt that a series set underwater could not be sustained. Tors then decided to sell it into the first-run syndication market. He teamed up with Ziv Television Programs and was able to sell it to more than 100 syndicated markets before it debuted in January 1958. Lloyd Bridges was cast as lead character Mike Nelson. ''Sea Hunt'' was intended as a comeback vehicle for Bridges due to his brief black-listing from acting. He was black-list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoignition Temperature
The autoignition temperature or kindling point of a substance is the lowest temperature in which it spontaneously ignites in a normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion. The temperature at which a chemical ignites decreases as the pressure is increased. *The ignition temperature of a substance is the lowest temperature at which the substance starts combustion. *Substances which spontaneously ignite in a normal atmosphere at naturally ambient temperatures are termed pyrophoric. Autoignition temperatures of liquid chemicals are typically measured using a flask placed in a temperature-controlled oven in accordance with the procedure described in ASTM E659. When measured for plastics, autoignition temperature can be also measured under elevated pressure and at 100% oxygen concentration. The resulting value is used as a predictor of viability for high-oxyge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colorless and odorless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids ( DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes the movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere. Many indus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Nitride
Magnesium nitride, which possesses the chemical formula Mg3N2, is an inorganic compound of magnesium and nitrogen. At room temperature and pressure it is a greenish yellow powder. Preparation * By passing dry nitrogen over heated magnesium: ::\begin\\ \ce\\ \end * or ammonia: ::\begin\\ \ce\\ \end History When isolating argon, William Ramsay passed dry air over copper to remove oxygen and over magnesium to remove the nitrogen, forming magnesium nitride. Chemistry Magnesium nitride reacts with water to produce magnesium hydroxide and ammonia gas, as do many metal nitrides. :Mg3N2(s) + 6 H2O(l) → 3 Mg(OH)2(aq) + 2 NH3(g) In fact, when magnesium is burned in air, some magnesium nitride is formed in addition to the principal product, magnesium oxide. Thermal decomposition of magnesium nitride gives magnesium and nitrogen gas (at 700-1500 °C). At high pressures, the stability and formation of new nitrogen-rich nitrides (N/Mg ratio equal or greater to one) were sugge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Oxide
Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + H2O → Mg(OH)2), but it can be reversed by heating it to remove moisture. Magnesium oxide was historically known as magnesia alba (literally, the white mineral from Magnesia), to differentiate it from ''magnesia negra'', a black mineral containing what is now known as manganese. Related oxides While "magnesium oxide" normally refers to MgO, the compound magnesium peroxide MgO2 is also known. According to evolutionary crystal structure prediction, MgO2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and a semiconducting suboxide Mg3O2 is thermodynamically stable above 500 GPa. Because of its stability, MgO is used as a model sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, or affinity of an ...—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, Carbon-12, C and Carbon-13, C being stable, while Carbon-14, C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the Timeline of chemical element discoveries#Ancient discoveries, few elements known since antiquity. Carbon is the 15th Abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the Abundance of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olympic Flame
The Olympic flame is a symbol used in the Olympic movement. It is also a symbol of continuity between ancient and modern games. Several months before the Olympic Games, the Olympic flame is lit at Olympia, Greece. This ceremony starts the Olympic torch relay, which formally ends with the lighting of the Olympic cauldron during the opening ceremony of the Olympic Games. The flame then continues to burn in the cauldron for the duration of the Games, until it is extinguished during the Olympic closing ceremony. Origins The Olympic flame as a symbol of the modern Olympic movement was introduced by architect Jan Wils who designed the stadium for the 1928 Summer Olympics in Amsterdam. The idea for the Olympic flame was derived from ancient Greek ceremonies where a sacred fire was kept burning throughout the celebration of the ancient Olympics on the altar of the sanctuary of Hestia. In Ancient Greek mythology, fire had divine connotations and it was thought to have been stolen fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minecraft
''Minecraft'' is a sandbox game developed by Mojang Studios. The game was created by Markus "Notch" Persson in the Java programming language. Following several early private testing versions, it was first made public in May 2009 before being fully released in November 2011, with Notch stepping down and Jens "Jeb" Bergensten taking over development. ''Minecraft'' is the best-selling video game of all time, with over 238 million copies sold and nearly 140 million monthly active players , and has been ported to several platforms. In ''Minecraft'', players explore a blocky, procedurally generated 3D world with virtually infinite terrain and may discover and extract raw materials, craft tools and items, and build structures, earthworks, and simple machines. Depending on their chosen game mode, players can fight hostile mobs, as well as cooperate with or compete against other players in the same world. Game modes include a survival mode (in which players must acquire resources t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Equipment
Diving equipment is equipment used by underwater divers to make diving activities possible, easier, safer and/or more comfortable. This may be equipment primarily intended for this purpose, or equipment intended for other purposes which is found to be suitable for diving use. The fundamental item of diving equipment used by divers other than freedivers, is underwater breathing apparatus, such as scuba equipment, and surface-supplied diving equipment, but there are other important items of equipment that make diving safer, more convenient or more efficient. Diving equipment used by recreational scuba divers, also known as scuba gear, is mostly personal equipment carried by the diver, but professional divers, particularly when operating in the surface supplied or saturation mode, use a large amount of support equipment not carried by the diver. Equipment which is used for underwater work or other activities which is not directly related to the activity of diving, or which has n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
