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Magnetohydrodynamic Converter
__NOTOC__ A magnetohydrodynamic converter (MHD converter) is an Electromagnetism, electromagnetic machine with no moving parts involving magnetohydrodynamics, the study of the kinetics (physics), kinetics of Electrical resistivity and conductivity, electrically conductive fluids (liquid or Plasma (physics), ionized gas) in the presence of electromagnetic fields. Such converters act on the fluid using the Lorentz force to operate in two possible ways: either as an electric generator called an magnetohydrodynamic generator, MHD generator, extracting energy from a fluid in motion; or as an electric motor called an MHD accelerator or magnetohydrodynamic drive, putting a fluid in motion by injecting energy. MHD converters are indeed reversible, like many electromagnetic devices. Michael Faraday first attempted to test a MHD converter in 1832. MHD converters involving plasmas were highly studied in the 1960s and 1970s, with many Subsidy, government funding and dedicated Academic conferenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interactions of atoms and molecules. Electromagnetism can be thought of as a combination of electrostatics and magnetism, which are distinct but closely intertwined phenomena. Electromagnetic forces occur between any two charged particles. Electric forces cause an attraction between particles with opposite charges and repulsion between particles with the same charge, while magnetism is an interaction that occurs between charged particles in relative motion. These two forces are described in terms of electromagnetic fields. Macroscopic charged objects are described in terms of Coulomb's law for electricity and Ampère's force law for magnetism; the Lorentz force describes microscopic charged particles. The electromagnetic force is responsible for ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academic Conference
An academic conference or scientific conference (also congress, symposium, workshop, or meeting) is an Convention (meeting), event for researchers (not necessarily academics) to present and discuss their scholarly work. Together with academic journal, academic or scientific journals and preprint archives, conferences provide an important channel for exchange of information between researchers. Further benefits of participating in academic conferences include learning effects in terms of presentation skills and "academic Habitus (sociology), habitus", receiving feedback from peers for one's own research, the possibility to engage in informal communication with peers about work opportunities and collaborations, and getting an overview of current research in one or more Academic discipline, disciplines. The first international academic conferences and congresses appeared in 19th century. Overview Conferences usually encompass various presentations. They tend to be short and conci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerospace
Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial, and military applications. Aerospace engineering consists of aeronautics and astronautics. Aerospace organizations research, design, manufacture, operate, maintain, and repair both aircraft and spacecraft. The border between space and the atmosphere has been proposed as above the ground according to the physical explanation that the air density is too low for a lifting body to generate meaningful lift force without exceeding orbital velocity. This border has been called the Kármán line. Overview In most industrial countries, the aerospace industry is a co-operation of the public and private sectors. For example, several states have a civilian space program funded by the government, such as NASA, National Aeronautics and Space Administration in the United States, European Space Agency in Europe, the Canadian Space A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measuremen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetohydrodynamic Drive
A magnetohydrodynamic drive or MHD accelerator is a method for propelling vehicles using only electric and magnetic fields with no moving parts, accelerating an electrically conductive propellant (liquid or gas) with magnetohydrodynamics. The fluid is directed to the rear and as a reaction, the vehicle accelerates forward. Studies examining MHD in the field of marine propulsion began in the late 1950s. Few large-scale marine prototypes have been built, limited by the low electrical conductivity of seawater. Increasing current density is limited by Joule heating and water electrolysis in the vicinity of electrodes, and increasing the magnetic field strength is limited by the cost, size and weight (as well as technological limitations) of electromagnets and the power available to feed them. In 2023 DARPA launched the PUMP program to build a marine engine using superconducting magnets expected to reach a field strength of 20 Tesla. Stronger technical limitations apply to air-brea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), work needed per unit of Electric charge, charge to move a positive Test particle#Electrostatics, test charge from the first point to the second point. In the SI unit, International System of Units (SI), the SI derived unit, derived unit for voltage is the ''volt'' (''V''). The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in a Electric generator, generator). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, and the thermoelectric effect. Since it is the difference in electric potential, it is a physical Scalar (physics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charge Carrier
In solid state physics, a charge carrier is a particle or quasiparticle that is free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors. Examples are electrons, ions and holes. In a conducting medium, an electric field can exert force on these free particles, causing a net motion of the particles through the medium; this is what constitutes an electric current. The electron and the proton are the elementary charge carriers, each carrying one elementary charge (''e''), of the same magnitude and opposite sign. In conductors In conducting mediums, particles serve to carry charge. In many metals, the charge carriers are electrons. One or two of the valence electrons from each atom are able to move about freely within the crystal structure of the metal. The free electrons are referred to as conduction electrons, and the cloud of free electrons is called a Fermi gas. Many metals have electron and hole bands. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Metal
A liquid metal is a metal or a metal alloy which is liquid at or near room temperature. The only stable liquid elemental metal at room temperature is Mercury (element), mercury (Hg), which is molten above −38.8 °C (234.3 K, −37.9 °F). Three more stable elemental metals melt just above room temperature: caesium (Cs), which has a melting point of 28.5 °C (83.3 °F); gallium (Ga) (30 °C [86 °F]); and rubidium (Rb) (39 °C [102 °F]). The radioactive metal francium (Fr) is probably liquid close to room temperature as well. Calculations predict that the radioactive metals copernicium (Cn) and flerovium (Fl) should also be liquid at room temperature. Alloys can be liquid if they form a eutectic, meaning that the alloy's melting point is lower than any of the alloy's constituent metals. The standard metal for creating liquid alloys used to be mercury (element), mercury, but gallium-based alloys, which are lower both in their vapor pressu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of either a positive or negative electric charge produces an electric field. The motion of electric charges is an electric current and produces a magnetic field. In most applications, Coulomb's law determines the force acting on an electric charge. Electric potential is the Work (physics), work done to move an electric charge from one point to another within an electric field, typically measured in volts. Electricity plays a central role in many modern technologies, serving in electric power where electric current is used to energise equipment, and in electronics dealing w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Energy
In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Robert and Halliday, David (1960) ''Physics'', Section 7-5, Wiley International Edition The kinetic energy of an object is equal to the work, or force ( F) in the direction of motion times its displacement ( s), needed to accelerate the object from rest to its given speed. The same amount of work is done by the object when decelerating from its current speed to a state of rest. The SI unit of energy is the joule, while the English unit of energy is the foot-pound. In relativistic mechanics, \fracmv^2 is a good approximation of kinetic energy only when ''v'' is much less than the speed of light. History and etymology The adjective ''kinetic'' has its roots in the Greek word κίνησις ''kinesis'', meaning "motion". The dichoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MHD Converters (generator And Accelerator)
MHD may refer to: * MHD (rapper), a French rapper from the 19th arrondissement of Paris ** ''MHD'' (album), the rapper's 2016 debut album * MHD, former name of the HDTV network for MTV, VH1, Palladia, and CMT now known as MTV Live * Mashhad International Airport's IATA code * Magnetohydrodynamics, the study of the magnetic properties and behaviour of electrically conducting fluids ** ''Magnetohydrodynamics'' (journal) * Malteser International, an aid agency * Menstrual Hygiene Day, a day to raise awareness about menstrual hygiene management issues * Military history detachment, a unit of United States Army * ''Mindesthaltbarkeitsdatum'', the German term for shelf life, printed on imported German food or medical products * Doctor of Marine Histories (DMH, formerly Marine Histories Doctorate or MHD), such as issued by Sea Research Society's College of Marine Arts * GNU libmicrohttpd, an embeddable HTTP server * Airline code for CAAC Airlines *''Městská hromadná doprava'' (Czec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Efficiency
Efficiency is the often measurable ability to avoid making mistakes or wasting materials, energy, efforts, money, and time while performing a task. In a more general sense, it is the ability to do things well, successfully, and without waste. In more mathematical or scientific terms, it signifies the level of performance that uses the least amount of inputs to achieve the highest amount of output. It often specifically comprises the capability of a specific application of effort to produce a specific outcome with a minimum amount or quantity of waste, expense, or unnecessary effort.Sickles, R., and Zelenyuk, V. (2019).Measurement of Productivity and Efficiency: Theory and Practice. Cambridge: Cambridge University Press. . Efficiency refers to very different inputs and outputs in different fields and industries. In 2019, the European Commission said: "Resource efficiency means using the Earth's limited resources in a sustainable procent manner while minimising impacts on the envi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
