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Monomethyl Hydrazine
Monomethylhydrazine (mono-methyl hydrazine, MMH) is a highly toxic, volatile hydrazine derivative with the chemical formula . It is used as a rocket propellant in bipropellant rocket engines because it is hypergolic with various oxidizers such as nitrogen tetroxide () and nitric acid (). As a propellant, it is described in specification MIL-PRF-27404. MMH is a hydrazine derivative that was once used in the orbital maneuvering system (OMS) and reaction control system (RCS) engines of NASA's Space Shuttle, which used MMH and MON-3 (a mixture of nitrogen tetroxide with approximately 3% nitric oxide). This chemical is toxic and carcinogenic, but it is easily stored in orbit, providing moderate performance for very low fuel tank system weight. MMH and its chemical relative unsymmetrical dimethylhydrazine (UDMH) have a key advantage that they are stable enough to be used in regeneratively cooled rocket engines. The European Space Agency (ESA) has attempted to seek new options in terms o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylamine
Methylamine is an organic compound with a formula of . This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine. Methylamine is sold as a solution in methanol, ethanol, tetrahydrofuran, or water, or as the anhydrous gas in pressurized metal containers. Industrially, methylamine is transported in its anhydrous form in pressurized railcars and tank trailers. It has a strong odor similar to rotten fish. Methylamine is used as a building block for the synthesis of numerous other commercially available compounds. Industrial production Methylamine is prepared commercially by the reaction of ammonia with methanol in the presence of an aluminosilicate catalyst. Dimethylamine and trimethylamine are co-produced; the reaction kinetics and reactant ratios determine the ratio of the three products. The product most favored by the reaction kinetics is trimethylamine. : In this way, an estimated 115,000 tons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suritozole
Suritozole (MDL 26,479) is an investigational cognition enhancer. It acts as a partial inverse agonist at the benzodiazepine receptor site on the GABAA ion channel complex, but does not have either anxiogenic or convulsant effects, unlike other BZD inverse agonists such as DMCM. It was investigated for the treatment of depression and Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ..., but clinical development seems to have been discontinued. Synthesis The reaction between monomethylhydrazine 0-34-4(1) and methyl isothiocyanate (Trapex) 56-61-6(2) gave 2,4-dimethylthiosemicarbazide 621-75-6(3). Amide formation with 3-fluorobenzoyl chloride 711-07-5(4) yielded 1-(3-fluorobenzoyl)-2,4-dimethylthiosemicarbazide 10623-52-4(5). Cyclization to Suritozole (6). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centers For Disease Control And Prevention
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgia. The agency's main goal is the protection of public health and safety through the control and prevention of disease, injury, and disability in the US and worldwide. The CDC focuses national attention on developing and applying disease control and prevention. It especially focuses its attention on infectious disease, food borne pathogens, environmental health, occupational safety and health, health promotion, injury prevention and educational activities designed to improve the health of United States citizens. The CDC also conducts research and provides information on non-infectious diseases, such as obesity and diabetes, and is a founding member of the International Association of National Public Health Institutes. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyromitrin
Gyromitrin is a toxin and carcinogen present in several members of the fungal genus ''Gyromitra'', like '' G. esculenta''. Its formula is . It is unstable and is easily hydrolyzed to the toxic compound monomethylhydrazine . Monomethylhydrazine acts on the central nervous system and interferes with the normal use and function of vitamin B6. Poisoning results in nausea, stomach cramps, and diarrhea, while severe poisoning can result in convulsions, jaundice, or even coma or death. Exposure to monomethylhydrazine has been shown to be carcinogenic in small mammals. History Poisonings related to consumption of the false morel '' Gyromitra esculenta'', a highly regarded fungus eaten mainly in Finland and by some in parts of Europe and North America, had been reported for at least a hundred years. Experts speculated the reaction was more of an allergic one specific to the consumer, or a misidentification, rather than innate toxicity of the fungus, due to the wide range in effects se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyromitra Esculenta
''Gyromitra esculenta'' is an ascomycete fungus from the genus ''Gyromitra'', widely distributed across Europe and North America. It normally fruits in sandy soils under coniferous trees in spring and early summer. The fruiting body, or mushroom, is an irregular brain-shaped cap dark brown in colour that can reach high and wide, perched on a stout white stipe up to high. Although potentially fatal if eaten raw, ''Gyromitra esculenta'' is a popular delicacy in Scandinavia, Eastern Europe, and the upper Great Lakes region of North America. Although popular in some districts of the eastern Pyrenees, it is prohibited from sale to the public in Spain. It may be sold fresh in Finland, but it must be accompanied by warnings and instructions on correct preparation. Although it is still commonly parboiled before preparation, evidence suggests that even this procedure may not make ''Gyromitra esculenta'' entirely safe for consumption. When consumed, the principal active agent, gy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyromitra
''Gyromitra'' () is a genus of about 18 species of ascomycete fungi. They are a false morel - a frequently toxic mushroom that can be mistaken for edible mushrooms of the genus ''Morchella'' (morels). Taxonomy The name ''Gyromitra'' comes from ''gyro'' meaning ''convoluted'' and ''mitra'' meaning ''turban''. Analysis of the ribosomal DNA of many of the Pezizales showed the genus ''Gyromitra'' to be most closely related to the genus '' Discina'', and also ''Pseudorhizina'', ''Hydnotrya'', and only distantly related to '' Helvella''. Thus the four genera are now included in the family Discinaceae. Species The genus consists of the following species: * ''Gyromitra ambigua'' * '' Gyromitra anthracobia'' * '' Gyromitra brunnea'' - known as a false morel * ''Gyromitra bubakii'' * '' Gyromitra californica'' * ''Gyromitra caroliniana'' (North America) * ''Gyromitra esculenta'' (Pers.) Fr. (1849) – a false morel * '' Gyromitra fastigiata'' * ''Gyromitra gigas'' – snow morel ** '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mushroom
A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is the cultivated white button mushroom, ''Agaricus bisporus''; hence the word "mushroom" is most often applied to those fungi ( Basidiomycota, Agaricomycetes) that have a stem ( stipe), a cap ( pileus), and gills (lamellae, sing. lamella) on the underside of the cap. "Mushroom" also describes a variety of other gilled fungi, with or without stems, therefore the term is used to describe the fleshy fruiting bodies of some Ascomycota. These gills produce microscopic spores that help the fungus spread across the ground or its occupant surface. Forms deviating from the standard morphology usually have more specific names, such as "bolete", "puffball", "stinkhorn", and " morel", and gilled mushrooms themselves are often called "agarics" in refere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Space Agency
, owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (12052189474).jpg , size = , caption = , acronym = , established = , employees = 2,200 , administrator = Director General Josef Aschbacher , budget = €7.2 billion (2022) , language = English and French (working languages) , website = , logo = European Space Agency logo.svg , logo_caption = Logo , image_caption = European Space Operations Centre (ESOC) Main Control Room The European Space Agency (ESA; french: Agence spatiale européenne , it, Agenzia Spaziale Europea, es, Agencia Espacial Europea ASE; german: Europäische Weltraumorganisation) is an intergovernmental organisation of 22 member states dedicated to the exploration of space. Established in 1975 and headquartered i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket Engine
A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accordance with Newton's third law. Most rocket engines use the combustion of reactive chemicals to supply the necessary energy, but non-combusting forms such as cold gas thrusters and nuclear thermal rockets also exist. Vehicles propelled by rocket engines are commonly called rockets. Rocket vehicles carry their own oxidiser, unlike most combustion engines, so rocket engines can be used in a vacuum to propel spacecraft and ballistic missiles. Compared to other types of jet engine, rocket engines are the lightest and have the highest thrust, but are the least propellant-efficient (they have the lowest specific impulse). The ideal exhaust is hydrogen, the lightest of all elements, but chemical rockets produce a mix of heavier species, reducing the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regenerative Cooling (rocketry)
Regenerative cooling, in the context of rocket engine design, is a configuration in which some or all of the propellant is passed through tubes, channels, or in a jacket around the combustion chamber or nozzle to cool the engine. This is effective because the propellants are often cryogenic. The heated propellant is then fed into a special gas-generator or injected directly into the main combustion chamber. History In 1857 Carl Wilhelm Siemens introduced the concept of regenerative cooling. On 10 May 1898, James Dewar used regenerative cooling to become the first to statically liquefy hydrogen. The concept of regenerative cooling was also mentioned in 1903 in an article by Konstantin Tsiolkovsky. Robert Goddard built the first regeneratively cooled engine in 1923, but rejected the scheme as too complex. A regeneratively cooled engine was built by the Italian researcher, Gaetano Arturo Crocco in 1930. The first Soviet engines to employ the technique were Fridrikh Tsander's OR-2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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