2 regard as unconnected; "you must dissociate these two events!"; "decouple our foreign policy from ideology" [syn: dissociate] [ant: associate]
3 eliminate airborne shockwaves from (an explosive)
4 reduce or eliminate the coupling of (one circuit or part to another)
The term "decoupling" is used in many different contexts.
PhysicsIn physics, decoupling is the general phenomenon in which the interactions between some physical objects (such as elementary particles) disappear.
In gauge theories, there are unobserved polarizations of elementary particles, such as the longitudinal photon. The experiments as well as theoretical consistency dictates that these polarizations cannot be produced by collisions of other particles. Consequently, their interactions with other (physical) particles must be equal to zero, and quantum electrodynamics confirms this expectation: decoupling is a consequence of gauge symmetry.
Physical cosmologyIn physical cosmology, the term "decoupling" is often used for the moment during recombination when the rate of Compton scattering became slower than the expansion of the universe, producing Cosmic Microwave Background as we know it.
BiologyIn biology, decoupling (used interchangeably with uncoupling) refers to the separation of the energy stored in the ion gradients inside mitochondria from the synthesis of ATP. Since this energy is not used to do work, it is dissipated as heat. This strategy is used by hibernating animals and infants to keep warm because their heat energy needs are higher than their ATP needs. Artificial decoupling has been used as a diet aid, often with disastrous results.
ElectronicsIn electronics, decoupling refers to the preventing of undesired coupling between subsystems via the power supply connections. Nowadays, this is commonly accomplished by connecting localized capacitors close to the power leads of integrated circuits to act as a small localized energy reservoir; these supply the circuit with current during transient, high current demand periods, preventing the voltage on the power supply rail from being pulled down by the momentary current load. See decoupling capacitor.
Rail transportIn rail transport, decoupling is the separation of two railroad cars by manipulation of their couplers.
Inventory managementIn Inventory Management, decoupling allows economy of scale within a single facility, and permits each process to operate at maximum efficiency rather than having the speed of the entire process constrained by the slowest.
Nuclear testingIn the underground nuclear testing (the testing of nuclear weapons), decoupling refers to the attempt to prevent some of the bomb's energy from transmitting as seismic waves. This makes it more difficult for outside observers to estimate the nuclear yield of the weapon being tested.
MathematicsIn mathematics, decoupling refers to the rearrangement of systems of equations so that they are independent of each other.
Utility RegulationIn public utility regulation, decoupling refers to the disassociation of a utility profit's from its sales of the energy commodity. Instead, a rate of return is aligned with meeting revenue targets, and rates are trued up or down to meet the target at the end of the adjustment period. This makes the utility indifferent to selling less product and improves the ability of energy efficiency and distributed generation to operate within the utility environment.
Ideally, utilities should be rewarded based on how well they meet their customers' energy service needs. However, most current rate design instead places the focus on commodity sales, tying a distribution company's recovery of fixed costs directly to its commodity sales.
In order to motivate utilities to consider all the options when planning and making resource decisions on how to meet their customers' needs, the sales-revenue link in current rate design must be broken. Breaking that link between the utility's commodity sales and revenues, removes both the incentive to increase electricity sales and the disincentive to run effective energy efficiency programs or invest in other activities that may reduce load. Decision-making then refocuses on making least-cost investments to deliver reliable energy services to customers even when such investments reduce throughput. The result is a better alignment of shareholder and customer interests to provide for more economically and environmentally efficient resource decisions.
As an added benefit, breaking the sales-revenue link streamlines the regulatory process for rate adjustments. Contention over sales forecasts consumes extensive time in every rate case. If the sales-revenue link is broken, these forecasts carry no economic weight, so the incentive to game forecasts of electricity sales is removed and rate cases become less adversarial.
EconomicsIn economics, decoupling refers to the lessening of correlation or dependency between variables. It is often used in the context of economic production and environmental quality. In this context, it refers to the ability of an economy to grow without corresponding increases in environmental pressure. In many economies increasing production (GDP) would involve increased pressure on the environment. An economy that is able to sustain GDP growth, without also experiencing a worsening of environmental conditions, is said to be decoupled. Exactly how, if, or to what extent this can be achieved is a subject of much debate.
Similarly, decoupling can refer to "breaking" the link between a dependent variable and its cause for a specific industry or activity. For instance, decoupling green house gas emissions from increasing electrical power generation.
The OECD has made decoupling a major focus of the work of its Environment Directorate. The OECD defines the term as follows:
- The term 'decoupling' refers to breaking the link between “environmental bads”and “economic goods.”
The same document then, in the following sentence, redefines the term in implementation language as meaning to have the rates of increasing wealth greater than the rates of increasing impacts. That alteration skirts the clear meaning of the term and the entire dilemma of continually accelerating our remaking of the earth from its effects. (OECD, 2002)