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Runaway Reaction
Thermal runaway describes a process that is accelerated by increased temperature, in turn releasing Thermal energy, energy that further increases temperature. Thermal runaway occurs in situations where an increase in temperature changes the conditions in a way that causes a further increase in temperature, often leading to a destructive result. It is a kind of uncontrolled positive feedback. In chemistry (and chemical engineering), thermal runaway is associated with strongly exothermic reactions that are accelerated by temperature rise. In electrical engineering, thermal runaway is typically associated with increased Electric current, current flow and power dissipation. Thermal runaway can occur in civil engineering, notably when the heat released by large amounts of Concrete#Curing, curing concrete is not controlled. In astrophysics, runaway nuclear fusion reactions in stars can lead to nova and several types of supernova explosions, and also occur as a less dramatic event in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global temperatures is Scientific consensus on climate change, driven by human activities, especially fossil fuel burning since the Industrial Revolution. Fossil fuel use, Deforestation and climate change, deforestation, and some Greenhouse gas emissions from agriculture, agricultural and Environmental impact of concrete, industrial practices release greenhouse gases. These gases greenhouse effect, absorb some of the heat that the Earth Thermal radiation, radiates after it warms from sunlight, warming the lower atmosphere. Carbon dioxide, the primary gas driving global warming, Carbon dioxide in Earth's atmosphere, has increased in concentratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium Flash
A helium flash is a very brief thermal runaway nuclear fusion of large quantities of helium into carbon through the triple-alpha process in the core of low-mass stars (between 0.5-0.44 solar masses () and 2.0 ) during their red giant phase. The Sun is predicted to experience a flash 1.2 billion years after it leaves the main sequence. A much rarer runaway helium fusion process can also occur on the surface of Accretion (astrophysics), accreting white dwarf stars. Low-mass stars do not produce enough gravity, gravitational pressure to initiate normal helium fusion. As the hydrogen in the core is exhausted, some of the helium left behind is instead compacted into degenerate matter, supported against gravitational collapse by quantum mechanics, quantum mechanical pressure rather than ideal gas law, thermal pressure. Subsequent hydrogen shell fusion further increases the mass of the core until it reaches temperature of approximately 100 million kelvin, which is hot enough to initiate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocracking
In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon–carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of large hydrocarbons into smaller, more useful alkanes and alkenes. Simply put, hydrocarbon cracking is the process of breaking long-chain hydrocarbons into short ones. This process requires high temperatures. More loosely, outside the field of petroleum chemistry, the term "cracking" is used to describe any type of splitting of molecules under the influence of heat, catalysts and solvents, such as in processes of destructive distillation or pyrolysis. Fluid catalytic cracking produces a high yield of petrol and LPG, while hydrocracking is a major source of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oil Refinery
An oil refinery or petroleum refinery is an industrial processes, industrial process Factory, plant where petroleum (crude oil) is transformed and refining, refined into products such as gasoline (petrol), diesel fuel, Bitumen, asphalt base, fuel oils, heating oil, kerosene, liquefied petroleum gas and petroleum naphtha. Petrochemical feedstock like ethylene and propene, propylene can also be produced directly by Cracking (chemistry), cracking crude oil without the need of using refined products of crude oil such as naphtha. The crude oil feedstock has typically been processed by an oil production plant. There is usually an oil depot at or near an oil refinery for the storage of incoming crude oil feedstock as well as bulk liquid products. In 2020, the total capacity of global refineries for crude oil was about 101.2 million barrels per day. Oil refineries are typically large, sprawling industrial complexes with extensive piping running throughout, carrying streams of fluids b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enthalpy
Enthalpy () is the sum of a thermodynamic system's internal energy and the product of its pressure and volume. It is a state function in thermodynamics used in many measurements in chemical, biological, and physical systems at a constant external pressure, which is conveniently provided by the large ambient atmosphere. The pressure–volume term expresses the work (physics), work W that was done against constant external pressure P_\text to establish the system's physical dimensions from V_\text=0 to some final volume V_\text (as W=P_\text\Delta V), i.e. to make room for it by displacing its surroundings. The pressure-volume term is very small for solids and liquids at common conditions, and fairly small for gases. Therefore, enthalpy is a stand-in for energy in chemical systems; Bond energy, bond, Lattice energy, lattice, solvation, and other chemical "energies" are actually enthalpy differences. As a state function, enthalpy depends only on the final configuration of internal e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Reaction
A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events. Chain reactions are one way that systems which are not in thermodynamic equilibrium can release energy or increase entropy in order to reach a state of higher entropy. For example, a system may not be able to reach a lower energy state by releasing energy into the environment, because it is hindered or prevented in some way from taking the path that will result in the energy release. If a reaction results in a small energy release making way for more energy releases in an expanding chain, then the system will typically collapse explosively until much or all of the stored energy has been released. A macroscopic metaphor for chain reactions is thus a snowball causing a larger snowball until finally an avalanche results (" snowball effect"). This is a result of stored gravitati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frank-Kamenetskii Theory
In combustion, Frank-Kamenetskii theory explains the Thermal runaway, thermal explosion of a homogeneous mixture of reactants, kept inside a closed vessel with constant temperature walls. It is named after a Russian scientist David A. Frank-Kamenetskii, who along with Nikolay Semyonov, Nikolay Semenov developed the theory in the 1930s. Problem description Sources: Consider a vessel maintained at a constant temperature T_o, containing a homogeneous reacting mixture. Let the characteristic size of the vessel be a. Since the mixture is homogeneous, the density \rho is constant. During the initial period of Combustion, ignition, the consumption of reactant concentration is negligible (see t_f and t_e below), thus the explosion is governed only by the energy equation. Assuming a one-step global reaction \text + \text \rightarrow \text + q, where q is the amount of heat released per unit mass of fuel consumed, and a reaction rate governed by Arrhenius law, the energy equation becomes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
King's Lynn
King's Lynn, known until 1537 as Bishop's Lynn and colloquially as Lynn, is a port and market town in the borough of King's Lynn and West Norfolk in the county of Norfolk, England. It is north-east of Peterborough, north-north-east of Cambridge and west of Norwich. History Toponymy The etymology of King's Lynn is uncertain. The name ''Lynn'' may signify a body of water near the town – the Welsh word means a lake; but the name is plausibly of Old English, Anglo-Saxon origin, from ''lean'' meaning a Tenure (law), tenure in fee or farm. The 1086 Domesday Book records it as ''Lun'' and ''Lenn'', and ascribes it to the Bishop of Elmham and the Archbishop of Canterbury. The Domesday Book also mentions saltings at Lena (Lynn); an area of partitioned pools may have existed there at the time. The presence of salt, which was relatively rare and expensive in the early medieval period, may have added to the interest of Herbert de Losinga and other prominent Normans in the modest parish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinitolmide
Dinitolmide (or zoalene) is a fodder additive for poultry, used to prevent coccidiosis infections. It is sold under trade names such as Coccidine A, Coccidot, and Zoamix. Dinitolmide is usually added to feed in doses of 125 ppm (preventive) or 250 ppm (curative). It is a broad-spectrum anticoccidial drug, preventing seven main strains of '' Eimeria coccidium''. It leaves no residues in tissues. It can be also used to prevent coccidiosis of domestic rabbit Rabbits are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated ...s. References External links Zoamix - DailyMed Nitrotoluene derivatives Poultry farming Benzamides {{antiinfective-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Nitrate
Ammonium nitrate is a chemical compound with the formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, but does not form hydrates. It is predominantly used in agriculture as a high-nitrogen fertilizer. Its other major use is as a component of explosive mixtures used in mining, quarrying, and civil construction. It is the major constituent of ANFO, an industrial explosive which accounts for 80% of explosives used in North America; similar formulations have been used in improvised explosive devices. Many countries are phasing out its use in consumer applications due to concerns over its potential for misuse.Ammonium nitrate sold by ton as U.S. regulati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas City Disaster
The 1947 Texas City disaster was an industrial accident that occurred on April 16, 1947, in the port of Texas City, Texas, United States, located in Galveston Bay. It was the deadliest industrial accident in U.S. history and one of history's largest non-nuclear explosions. The explosion was triggered by a mid-morning fire on board the French-registered vessel SS ''Grandcamp'' (docked at port), which detonated her cargo of about 2,300 tons (about 2,100 metric tons) of ammonium nitrate. This started a chain reaction of fires and explosions aboard other ships and in nearby oil-storage facilities, ultimately killing at least 581 people, including all but one member of Texas City's volunteer fire department. The disaster drew the first class action lawsuit against the United States government, on behalf of 8,485 plaintiffs, under the 1946 Federal Tort Claims Act. Ships SS ''Grandcamp'' was a recently re-activated 437-foot-long (133 m) Liberty ship. Originally named SS ''Benjami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Accidents
A chemical accident is the unintentional release of one or more hazardous chemicals, which could harm human health and the environment. Such events include fires, explosions, and release of toxic materials that may cause people illness, injury, or disability. Chemical accidents can be caused for example by natural disasters, human error, or deliberate acts for personal gain. Chemical accidents are generally understood to be industrial-scale ones, often with important offsite consequences. Unintended exposure to chemicals that occur at smaller work sites, as well as in private premises during everyday activities are usually not referred to as chemical accidents. Process safety is the engineering discipline dealing with chemical accident hazards understanding and management. Process safety's scope extends however to fires and explosions from hazardous materials generally not referred to as 'chemicals', such as refined and unrefined hydrocarbon mixtures. Frequency United States Che ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
