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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 ?
2] kinetic response for exercise increments to steady state for different incremental magnitudes, and the same magnitude from different baseline intensities;
The policymaker is completely committed to interest rate adjustment as the main tool of monetary policy, even long after it ceases to make sense (long after policy becomes passive), creating a second steady state for the economy.
In steady state, [kappa] and E must grow at the same rate for k to be constant at k*.
1] at the nominal steady state loses the function of the CBS activation by AdoMet at t=0.
Methods: By practice of DHA-rich algae oil administration by enteral methods for both nutritive and non-nutritive purposes, there are structure/function roles for DHA to be discussed, but these are deemed correlative to any specified outcome other than to measurable steady state omega-3 levels.
e] is not zero, the state of the controller is 'pulled' toward the steady state prediction.
Third, multiple steady state solutions necessitate dynamic stability analysis.
Resulting from unevenness of both the angular velocity and the driving torque the steady state appears in the form of the steady state motion.
When that bound is imposed and the model is studied nonlinearly, it becomes clear that (i) there is a second steady-state equilibrium at a lower inflation rate, and (ii) there are many non-steady-state equilibria in which the inflation rate converges to the low-inflation steady state in the long run.
At steady state, which was achieved at both dose levels by the sixth day of treatment, both the maximum CK-2017357 plasma concentration (Cmax) and the area under the CK-2017357 plasma concentration versus time curve from dosing until 24 hours after dosing (AUC24h) were generally dose proportional and exhibited only modest accumulation compared to the values measured after the first dose.
Rob Dietz of Corvallis is the executive director of the Center for the Advancement of the Steady State Economy.

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