# ⓘ Energy (physics)

## Anisotropy energy

Anisotropic energy is energy that is directionally specific. The word anisotropy means "directionally dependent", hence the definition. The most common form of anisotropic energy is magnetocrystalline anisotropy, which is commonly studied in ferrimagnets. In ferrimagnets, there are islands or domains of atoms that are all coordinated in a certain direction; this spontaneous positioning is often called the "easy" direction, indicating that this is the lowest energy state for these atoms. In order to study magnetocrystalline anisotropy, energy is applied to the domain, which causes the cryst ...

## Binding energy

In physics, binding energy is the minimum energy required to disassemble a system of particles into separate parts. This energy is equal to the mass defect minus the amount of energy, or mass, that is released when a bound system is created, and is what keeps the system together.

## Characteristic energy

In astrodynamics, the characteristic energy is a measure of the excess specific energy over that required to just barely escape from a massive body. The units are length 2  time −2, i.e. velocity squared or twice the energy per mass. Every object in a 2-body ballistic trajectory has a constant specific orbital energy ϵ {\displaystyle \epsilon } equal to the sum of its specific kinetic and specific potential energy: ϵ = 1 2 v 2 − μ r = constant = 1 2 C 3, {\displaystyle \epsilon ={\frac {1}{2}}v^{2}-{\frac {\mu }{r}}={\text{constant}}={\frac {1}{2}}C_{3},} where μ = G M {\displaystyle \mu = ...

## Conservation of energy

In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another. For instance, chemical energy is converted to kinetic energy when a stick of dynamite explodes. If one adds up all forms of energy that were released in the explosion, such as the kinetic energy and potential energy of the pieces, as well as heat and sound, one will get the exact decreas ...

## Dark energy

In physical cosmology and astronomy, dark energy is a term that describes an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from supernovae measurements, which showed that the universe does not expand at a constant rate; rather, the expansion of the universe is accelerating. Understanding the evolution of the universe requires knowledge of the starting conditions and what it consists of. Prior to these observations, the only forms of matter-energy known to exist were ordinary matter, dark matter, and radiation ...

## DPIE

DPIE - discrete-pulse input of energy equipment realizes basic mechanisms and effects of the movements of a continuous phase connected with acceleration, action of pressure of shift, cavitations mechanisms, the mechanism of explosive boiling, collective effects in ensemble of vials and indignations of an interphase surface in liquid-gas bubble environments in scientific investigations.

## Energy current

Energy current is a flow of energy defined by the Poynting vector, as opposed to normal current. It was originally postulated by Oliver Heaviside. It is also an informal name for Energy flux.

## Energy functional

The Energy functional is the total energy of a certain system, as a functional of the systems state. In the energy methods of simulating the dynamics of complex structures, a state of the system is often described as an element of an appropriate function space. To be in this state, the system pays a certain cost in terms of energy required by the state. This energy is a scalar quantity, a function of the state, hence the term functional. The system tends to develop from the state with higher energy higher cost to the state with lower energy, thus local minima of this functional are usually ...

## Enthalpy

Enthalpy, a property of a thermodynamic system, is equal to the systems internal energy plus the product of its pressure and volume. In a system enclosed so as to prevent mass transfer, for processes at constant pressure, the heat absorbed or released equals the change in enthalpy. The unit of measurement for enthalpy in the International System of Units SI is the joule. Other historical conventional units still in use include the British thermal unit BTU and the calorie. Enthalpy comprises a systems internal energy, which is the energy required to create the system, plus the amount of wor ...

## Equivalent dumping coefficient

An equivalent dumping coefficient is a mathematical coefficient used in the calculation of the energy dispersed when a structure moves. As a civil engineering term, it defines the percent of a cycle of oscillation that is absorbed for the structure or sub-structure under analysis. Usually it is assumed that the equivalent dumping coefficient is linear, which is to say invariant compare to oscillatory amplitude. Modern seismic studies have shown this not to be a satisfactory assumption for larger civic structures, and have developed sophisticated amplitude and frequency based functions for ...

## Generic object of dark energy

Generic object of dark energy refers to a class of non-singular theoretical objects that mimic black holes, but with dark energy interiors instead. They have been hypothesized to result from the collapse of very large stars by Leningrad physicist Erast Gliner at the Ioffe Physico-Technical Institute in 1966. Such GEODEs appear to be black holes when viewed from afar but, different from black holes, these objects contain dark energy instead of a gravitational singularity. Contrary to classical black holes, GEODEs may intrinsically gain mass via the same relativistic effect responsible for t ...

## Gravitational potential

In classical mechanics, the gravitational potential at a location is equal to the work per unit mass that would be needed to move an object to that location from a fixed reference location. It is analogous to the electric potential with mass playing the role of charge. The reference location, where the potential is zero, is by convention infinitely far away from any mass, resulting in a negative potential at any finite distance. In mathematics, the gravitational potential is also known as the Newtonian potential and is fundamental in the study of potential theory. It may also be used for s ...

## Interaction energy

In physics, interaction energy is the contribution to the total energy that is caused by an interaction between the objects being considered. The interaction energy usually depends on the relative position of the objects. For example, Q 1 Q 2 / 4 π ϵ 0 Δ r {\displaystyle Q_{1}Q_{2}/4\pi \epsilon _{0}\Delta r} is the electrostatic interaction energy between two objects with charges Q 1 {\displaystyle Q_{1}}, Q 2 {\displaystyle Q_{2}}.

## Internal energy

In thermodynamics, the internal energy of a system is the energy contained within the system. It is the energy necessary to create or prepare the system in any given state, but does not include the kinetic energy of motion of the system as a whole, nor the potential energy of the system as a whole due to external force fields which includes the energy of displacement of the systems surroundings. It keeps account of the gains and losses of energy of the system that are due to changes in its internal state. The internal energy of a system can be increased by introduction of matter, by heat, ...

## Invariant mass

The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system. More precisely, it is a characteristic of the systems total energy and momentum that is the same in all frames of reference related by Lorentz transformations. If a center-of-momentum frame exists for the system, then the invariant mass of a system is equal to its total mass in that "rest frame". In other reference frames, where the systems momentum is nonzero, the ...

## Josephson effect

The Josephson effect is the phenomenon of supercurrent, a current that flows indefinitely long without any voltage applied, across a device known as a Josephson junction, which consists of two or more superconductors coupled by a weak link. The weak link can consist of a thin insulating barrier, a short section of non-superconducting metal, or a physical constriction that weakens the superconductivity at the point of contact. The Josephson effect is an example of macroscopic quantum phenomena. It is named after British physicist Brian David Josephson, who predicted in 1962 the mathematical ...

## Kilocalorie per mole

The kilocalorie per mole is a unit to measure an amount of energy per number of molecules, atoms, or other similar particles. It is defined as one kilocalorie of energy per one mole of substance, that is, per Avogadro’s number of particles. It is abbreviated "kcal/mol" or "kcal mol −1 ". As typically measured, one kcal/mol represents a temperature increase of one degree Celsius in one liter of water resulting from the reaction of one mole of reagents. In SI units, one kilocalorie per mole is equal to 4.184 kilojoules per mole, or 6.9477 × 10 −21 joules per molecule, or 0.043 eV per molecul ...

## Mass–energy equivalence

In physics, mass–energy equivalence is the principle that anything having mass has an equivalent amount of energy and vice versa, with these fundamental quantities directly relating to one another by Albert Einsteins famous formula: This formula states that the equivalent energy E can be calculated as the mass m is multiplied by the speed of light c = ~ 3 × 10 8 m / s squared. Similarly, anything having energy exhibits a corresponding mass m given by its energy e divided by the speed of light squared c 2. Because the speed of light is a very large number in everyday unit, the formula impli ...

## Mechanical energy

In physical sciences, mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object. The principle of conservation of mechanical energy states that in an isolated system that is only subject to conservative forces, the mechanical energy is constant. If an object moves in the opposite direction of a conservative net force, the potential energy will increase; and if the speed of the object changes, the kinetic energy of the object also changes. In all real systems, however, nonconservative forces, such as frictional ...

## Ponderomotive energy

In atomic units, e = m = 1 {\displaystyle e=m=1}, ϵ 0 = 1 / 4 π {\displaystyle \epsilon _{0}=1/4\pi }, α c = 1 {\displaystyle \alpha c=1} where α ≈ 1 / 137 {\displaystyle \alpha \approx 1/137}. If one uses the atomic unit of electric field, then the ponderomotive energy is just U p = E a 2 4 ω 0 2. {\displaystyle U_{p}={\frac {E_{a}^{2}}{4\omega _{0}^{2}}}.}

## QED vacuum

The QED vacuum is the field-theoretic vacuum of quantum electrodynamics. It is the lowest energy state of the electromagnetic field when the fields are quantized. When Plancks constant is hypothetically allowed to approach zero, QED vacuum is converted to classical vacuum, which is to say, the vacuum of classical electromagnetism. Another field-theoretic vacuum is the QCD vacuum of the Standard Model.

## Quantum fluctuation

In quantum physics, a quantum fluctuation is the temporary change in the amount of energy in a point in space, as explained in Werner Heisenbergs uncertainty principle. This allows the creation of particle-antiparticle pairs of virtual particles. The effects of these particles are measurable, for example, in the effective charge of the electron, different from its "naked" charge. Quantum fluctuations may have been necessary in the origin of the structure of the universe: according to the model of expansive inflation the ones that existed when inflation began were amplified and formed the s ...

## Specific energy

Energy density has tables of specific energies of devices and materials. Specific energy or massic energy is energy per unit mass. It is also sometimes called gravimetric energy density, or just energy density though energy density more precisely means energy per unit volume. It is used to quantify, for example, stored heat and other thermodynamic properties of substances such as specific internal energy, specific enthalpy, specific Gibbs free energy, and specific Helmholtz free energy. It may also be used for the kinetic energy or potential energy of a body. Specific energy is an intensiv ...

## Specific kinetic energy

Specific kinetic energy is kinetic energy of an object per unit of mass. It is defined as e k = 1 2 v 2 {\displaystyle {\begin{matrix}e_{k}={\frac {1}{2}}\end{matrix}}v^{2}}. Where e k {\displaystyle e_{k}} is the specific kinetic energy and v {\displaystyle v} is velocity. It has units of J/kg, which is equivalent to m 2 /s 2.

## Specific mechanical energy

Specific mechanical energy is the mechanical energy of an object per unit of mass. Similar to mechanical energy, the specific mechanical energy of an object in an isolated system subject only to conservative forces will remain constant. It is defined as: e = e k + e p {\displaystyle {\begin{aligned}e&amp;=e_{k}+e_{p}\end{aligned}}} where e k {\displaystyle e_{k}} is the specific kinetic energy e p {\displaystyle e_{p}} it the specific potential energy

## Specific potential energy

Specific potential energy is potential energy of an object per unit of mass of that object. In a gravitational field it is the acceleration of gravity times height, e u = g h {\displaystyle e_{u}=gh}.

## Thermodynamic free energy

The thermodynamic free energy is a concept useful in the thermodynamics of chemical or thermal processes in engineering and science. The change in the free energy is the maximum amount of work that a thermodynamic system can perform in a process at constant temperature, and its sign indicates whether a process is thermodynamically favorable or forbidden. Since free energy usually contains potential energy, it is not absolute but depends on the choice of a zero point. Therefore, only relative free energy values, or changes in free energy, are physically meaningful. The free energy is a ther ...

## Threshold energy

In particle physics, the threshold energy for production of a particle is the minimum kinetic energy a pair of traveling particles must have when they collide. The threshold energy is always greater than or equal to the rest energy of the desired particle. In most cases, since momentum is also conserved, the threshold energy is significantly greater than the rest energy of the desired particle - and thus there will still be considerable kinetic energy in the final particles.

## Time translation symmetry

Time translation symmetry or temporal translation symmetry is a mathematical transformation in physics that moves the times of events through a common interval. Time translation symmetry is the hypothesis that the laws of physics are unchanged, under such a transformation. Time translation symmetry is a rigorous way to formulate the idea that the laws of physics are the same throughout history. Time translation symmetry is closely connected, via the Noether theorem, to conservation of energy. In mathematics, the set of all time translations on a given system form a Lie group. There are man ...

## Turbulence kinetic energy

In fluid dynamics, turbulence kinetic energy is the mean kinetic energy per unit mass associated with eddies in turbulent flow. Physically, the turbulence kinetic energy is characterised by measured root-mean-square velocity fluctuations. In Reynolds-averaged Navier Stokes equations, the turbulence kinetic energy can be calculated based on the closure method, i.e. a turbulence model. Generally, the TKE is defined to be half the sum of the variances square of standard deviations of the velocity components: k = 1 2 u ′ 2 ¯ + v ′ 2 ¯ + w ′ 2 ¯), {\displaystyle k={\frac {1}{2}}\left\,{\overlin ...

## Vacuum energy

Vacuum energy is an underlying background energy that exists in space throughout the entire Universe. Its behavior is codified in Heisenbergs energy–time uncertainty principle. Still, the exact effect of such fleeting bits of energy is difficult to quantify. The vacuum energy is a special case of zero-point energy that relates to the quantum vacuum. The effects of vacuum energy can be experimentally observed in various phenomena such as spontaneous emission, the Casimir effect and the Lamb shift, and are thought to influence the behavior of the Universe on cosmological scales. Using the up ...

## Versatile Test Reactor

After the Fast Flux Test Facility and the Experimental Breeder Reactor-II EBR-II were decommissioned in, respectively, 1992 and 1994, the United States was left with no fast-neutron reactor in its fleet. Fast-neutron research was limited to a few restricted reactors located in Russia, including the Bor-60. To address this problem Nuclear Energy Innovation Capabilities Act of 2017 included a provision directing the Department of Energy to begin planning for a fast-neutron source. Congress included $35 million in 2018 and$65 million in 2019 in the budget in support of this. In February 2019 ...

## Work (physics)

Work is the product of force and displacement. In physics, a force is said to do work if, when acting, there is a movement of the point of application in the direction of the force. For example, when a ball is held above the ground and then dropped, the work done on the ball as it falls is equal to the weight of the ball a force multiplied by the distance to in ground a displacement. When the force F {\the style property display set to F} is constant and the angle between the force and the displacement s {\properties display style value s} is θ, then the work done is given by W = Fs cos θ. ...

## Zero-point energy

Zero-point energy is the lowest possible energy that a quantum mechanical system may have. Unlike in classical mechanics, quantum systems constantly fluctuate in their lowest energy state as described by the Heisenberg uncertainty principle. As well as atoms and molecules, the empty space of the vacuum has these properties. According to quantum field theory, the universe can be thought of not as isolated particles but continuous fluctuating fields: matter fields, whose quanta are fermions, and force fields, whose quanta are bosons. All these fields have zero-point energy. These fluctuating ...

## ⓘ Energy (physics)

• In physics binding energy also called separation energy is the minimum energy required to disassemble a system of particles into separate parts. This
• State Research Center - Institute for High Energy Physics IHEP is a research organisation in Protvino near Moscow, Moscow Oblast Russia. It was established
• In physics work is the product of force and displacement. A force is said to do work if, when acting, there is a movement of the point of application
• In particle physics a calorimeter is an experimental apparatus that measures the energy of particles. Most particles enter the calorimeter and initiate
• traditional fields such as High Energy Physics and Condensed Matter Physics Material Science, and Biological Physics but also topics like Seismic and
• to physics Physics natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and
• nuclear engineering, biophysics, control theory, aerodynamics, energy solid - state physics etc. It is the discipline devoted to creating and optimizing
• High energy may refer to: High energy physics a branch of physics dealing with subatomic particles and ionizing radiation Hi - NRG, a kind of dance music
• laser physics ponderomotive energy is the cycle - averaged quiver energy of a free electron in an electromagnetic field. The ponderomotive energy is given
• Energy efficiency may refer to: Energy efficiency physics the ratio between the useful output and input of an energy conversion process Electrical

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