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Physics the condition of a system when some or all of the quantities describing it are independent of time but not necessarily in thermodynamic or chemical equilibrium

(in some contexts, stationary state), in physics, a state of a physical system in which some quantities significant for characterizing the system (different quantities in different cases) do not vary with time. For example, the state of flow of a fluid is a steady state if the rate of motion and other characteristics remain invariant at each point in space. In quantum mechanics, a state in which the energy has a specific and time-invariant value is called a stationary state. (SeeOPEN SYSTEMS and PRIGOGINETHEOREM regarding steady states in thermodynamics.) The state of a system is quasi-stationary (in thermodynamics, quasi-static) if those quantities that, if constant, would make the state a steady state change slowly with time. Here, the relations between various properties of the system remain approximately the same as in a steady state.

the state to which a mechanism or system returns after the occurrence of a transient produced by a perturbation or an initial deviation in the system’s coordinates.

Examples of steady states in linear systems include the rotation of an engine at some fixed rate with a constant load applied to the shaft, harmonic oscillations in an oscillatory circuit, and the operation of an automatic control system with constant perturbations and control inputs. The steady state of a dynamic system is characterized by having the forces acting on the system compensated by a corresponding counteraction. For example, the motion of a rotating mechanism is described by the equation Md = Mr, where Md is the driving torque and Mr is the resisting torque. For a body being heated, Qh = Qd, where Qh and Qd represent, respectively, the amount of heat absorbed by the body during heating and the amount dissipated to the environment. In an oscillatory circuit, Ws = Wh, where Ws and Wh are, respectively, the amount of energy supplied from a power source during one period of the oscillation and the amount evolved as heat in the resistance of the circuit.

[′sted·ē ′stāt]
(physics)
The condition of a body or system in which the conditions at each point do not change with time, that is after initial transients or fluctuations have disappeared.
References in periodicals archive ?
Table 8 shows the actual growth in labor productivity and steady-state estimates of labor productivity growth over the full period from 1974 to 2015.
Two testing processes were used to map each engine while it was on an engine dynamometer and tethered to its respective vehicle, intending to cover both steady-state and transient operation.
One can approach the book as one would a smorgasbord lunch, sampling dishes according to personal taste, rather than sitting down to a meal of Daly's bigger books such as Steady-State Economics, For the Common Good, Beyond Growth or Ecological Economics.
However, exercise at a maximal steady-state has the potential to display dissimilar threshold points through different bioenergetic responses.
1] the steady-state need for ART initiation is determined by the historical annual infection rates and is not influenced by a change in [CD4.
This alters the targeted steady-state inflation rate of the economy from 1.
New steady-state of the model at pathological consequences (loss of [V.
So there is a complex engineering equation, a power law, that plots the expected time to failure based on this secondary steady-state creep with variations for different temperatures and stresses.
The alternative way of the steady-state error elimination is to add an adjustable reset term to the control signal or to add a corrective term to the input of system with P or PD controller.
More specifically, we have a steady-state, or coherent, sequence in which the image contrast depends upon the T2- to T1-ratio.
The original guidelines were calculated from steady-state analysis.
The dynamic stability of multiple steady state solutions and the comparative steady-state effects of shocks in sustainable public debt levels are investigated thereafter.

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