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Biography
Edwin C. Kemble
Edwin Crawford Kemble (January 28, 1889 in Delaware, Ohio – March 12, 1984) was an American physicist who made contributions to the theory of quantum mechanics and molecular structure and spectroscopy. During World War II, he was a consultant to the Navy on acoustic detection of submarines and to the Army on Operation Alsos.[1] Kemble began college in 1906 at Ohio Wesleyan University, but h
  • 477
  • 08 Dec 2022
Topic Review
Effective Atomic Number
Effective atomic number has two different meanings: one that is the effective nuclear charge of an atom, and one that calculates the average atomic number for a compound or mixture of materials. Both are abbreviated Zeff.
  • 2.0K
  • 22 Nov 2022
Topic Review
Effects in Molecular Nanomagnets
Molecular magnets, in principle, have a similar hierarchy. Starting from single-molecule magnets (SMM)and single-chain magnets (SCM), more complex structures are also possible. In general, molecular nanomagnets can be built without the aforementioned magnetic elements; however, highly interesting molecular nanomagnets can be created by adding Mn12, Fe8, Mn4, or other metallic elements.
  • 485
  • 26 Aug 2021
Topic Review
Eightfold Way
In physics, the eightfold way is an organizational scheme for a class of subatomic particles known as hadrons that led to the development of the quark model. American physicist Murray Gell-Mann and Israeli physicist Yuval Ne'eman both proposed the idea in 1961. The name comes from Gell-Mann's (1961) paper and is an allusion to the Noble Eightfold Path of Buddhism.
  • 947
  • 17 Oct 2022
Topic Review
Einstein's Constant
Einstein's gravitational constant, denoted κ (kappa), is the constant appearing in the Einstein field equation which can be written: where Gαγ is the Einstein tensor and Tαγ is the stress–energy tensor. This equation relates to the curvature of spacetime, indicating that stress–energy is what causes the curvature of spacetime, thus gravitation. The constant κ is directly related to Newton's gravitational constant G: The above is for the stress–energy tensor in units of mass density (i.e., mass per volume). The units of Einstein's constant depends on how the stress–energy tensor is defined, so an alternative choice for T with units of energy density (i.e., energy per volume) yields
  • 497
  • 14 Nov 2022
Topic Review
Elasticity
In physics and materials science, elasticity is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. Solid objects will deform when adequate loads are applied to them; if the material is elastic, the object will return to its initial shape and size after removal. This is in contrast to plasticity, in which the object fails to do so and instead remains in its deformed state. The physical reasons for elastic behavior can be quite different for different materials. In metals, the atomic lattice changes size and shape when forces are applied (energy is added to the system). When forces are removed, the lattice goes back to the original lower energy state. For rubbers and other polymers, elasticity is caused by the stretching of polymer chains when forces are applied. Hooke's law states that the force required to deform elastic objects should be directly proportional to the distance of deformation, regardless of how large that distance becomes. This is known as perfect elasticity, in which a given object will return to its original shape no matter how strongly it is deformed. This is an ideal concept only; most materials which possess elasticity in practice remain purely elastic only up to very small deformations, after which plastic (permanent) deformation occurs. In engineering, the elasticity of a material is quantified by the elastic modulus such as the Young's modulus, bulk modulus or shear modulus which measure the amount of stress needed to achieve a unit of strain; a higher modulus indicates that the material is harder to deform. The SI unit of this modulus is the pascal (Pa). The material's elastic limit or yield strength is the maximum stress that can arise before the onset of plastic deformation. Its SI unit is also the pascal (Pa).
  • 1.6K
  • 06 May 2023
Topic Review
Electricity Meter
thumb|North American domestic analogue electricity meter. thumb|Electricity meter with transparent plastic case (Israel) thumb|North American domestic electronic electricity meter An electricity meter, electric meter, electrical meter, or energy meter is a device that measures the amount of electric energy consumed by a residence, a business, or an electrically powered device. Electric utilities use electric meters installed at customers' premises for billing and monitoring purposes. They are typically calibrated in billing units, the most common one being the kilowatt hour (kWh). They are usually read once each billing period. When energy savings during certain periods are desired, some meters may measure demand, the maximum use of power in some interval. "Time of day" metering allows electric rates to be changed during a day, to record usage during peak high-cost periods and off-peak, lower-cost, periods. Also, in some areas meters have relays for demand response load shedding during peak load periods.
  • 721
  • 27 Oct 2022
Topic Review
Electrification Mechanism of Smart Textile Triboelectric Nanogenerators
Triboelectrification or contact electrification is a universal phenomenon in which two materials contact each other. A triboelectric nanogenerator (TENG) is a new type of energy collection technology first invented by Wang’s team in 2012. By coupling triboelectric charging and electrostatic induction, various forms of irregular, low-frequency, and distributed mechanical energy, which is common in daily life but usually wasted, can be effectively converted into electric energy, including human movement, vibration, wind, mechanical triggering, water waves, and so on.
  • 809
  • 21 Mar 2022
Topic Review
Electro-gyration
The electrogyration effect is the spatial dispersion phenomenon, that consists in the change of optical activity (gyration) of crystals by a constant or time-varying electric field. Being a spatial dispersion effect, the induced optical activity exhibit different behavior under the operation of wave vector reversal, when compared with the Faraday effect: the optical activity increment associated with the electrogyration effect changes its sign under that operation, contrary to the Faraday effect. Formally, it is a special case of gyroelectromagnetism obtained when the magnetic permeability tensor is diagonal. 
  • 774
  • 05 Dec 2022
Topic Review
Electro-Osmosis
Electroosmotic flow (or electro-osmotic flow, often abbreviated EOF; synonymous with electroosmosis or electroendosmosis) is the motion of liquid induced by an applied potential across a porous material, capillary tube, membrane, microchannel, or any other fluid conduit. Because electroosmotic velocities are independent of conduit size, as long as the electrical double layer is much smaller than the characteristic length scale of the channel, electroosmotic flow will have little effect. Electroosmotic flow is most significant when in small channels. Electroosmotic flow is an essential component in chemical separation techniques, notably capillary electrophoresis. Electroosmotic flow can occur in natural unfiltered water, as well as buffered solutions.
  • 985
  • 29 Nov 2022
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