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Showing papers on "Transient (oscillation) published in 1978"


Journal ArticleDOI
TL;DR: In this article, an efficient finite difference simulation procedure for the steady state and transient solution of the Nernst-Planck and Poisson equation system is presented, containing refinements in time and distance scaling.

242 citations


Journal ArticleDOI
TL;DR: Five heuristic rules for predicting the approximate end of transiency, four of which have been quoted extensively in the simulation literature, have been evaluated in the M/M/1 situation and performed poorly.
Abstract: A definition of the problem of the initial transient with respect to the steady-state mean value has been formulated. A set of criteria has been set forth by which the efficaacy of any proposed rule may be assessed. Within this framework, five heuristic rules for predicting the approximate end of transiency, four of which have been quoted extensively in the simulation literature, have been evaluated in the M/M/1 situation. All performed poorly and are not suitable for their intended use.

133 citations


Journal ArticleDOI
TL;DR: In this article, the authors present rigorous working equations for an automatic Wheatstone bridge employed in fluid thermal conductivity measurements by the transient hot-wire technique, focusing on the inevitable small differences between the two wires employed for the cancellation of the end effects in the experimental arrangement.
Abstract: The paper presents rigorous working equations for an automatic Wheatstone bridge employed in fluid thermal conductivity measurements by the transient hot-wire technique. Particular attention is concentrated upon the inevitable small differences between the two wires employed for the cancellation of the end effects in the experimental arrangement. It is shown that from experimental measurements of the change in the difference of resistance of the two wires as a function of time during their transient heating, it is possible to determine the temperature rise of a wire acting as a finite section of an infinite wire. The correct expressions for the calculation of the heat flux in the wire are also given.

130 citations


Journal ArticleDOI
TL;DR: In this paper, a test of the predictive capabilities of the three-dimensional finite-difference method for realistic aircraft simulator test problems has been conducted on an aircraft when it was exposed to the transient electromagnetic field of an electromagnetic pulse (EMP) simulator.
Abstract: Experimental charge and current measurements have recently been performed on an aircraft when it was exposed to the transient electromagnetic fi'eld of an electromagnetic pulse (EMP) simulator. These new data allow a test of the predictive capabilities of the three-dimensional finite-difference method for realistic aircraft simulator test problems. In the paper, the workings of the threedimensional finite-difference method and its required inputs and sensitivity to variations in the inputs are discussed in sufficient detail to enable others to employ the method. A companion paper compares the experimental measurements to predictions for a large variety of measurement locations. Agreement is shown to be good for all major response measurements and satisfactory for a number of other measurements.

121 citations


Journal ArticleDOI
TL;DR: A general description of polymeric dielectrics in low fields, including polarisation and depolarisation, and transient and steady state conduction, in isothermal and non-isothermal conditions is given in this paper.
Abstract: A general description is given of the behavior of polymeric dielectrics in low fields, including polarisation and depolarisation, and transient and steady state conduction, in isothermal and non-isothermal conditions. An attempt is made to present a unified interpretation applicable to all of these phenomena.

74 citations


Journal ArticleDOI
TL;DR: In this article, a theoretical and experimental study on the transient characteristics of a nonlinear Fabry-Perot filled with Kerr liquid is carried out, and the steady-state operation is deduced.
Abstract: We have carried out a theoretical and experimental study on the transient characteristics of a nonlinear Fabry‐Perot filled with Kerr liquid. Agreement between theory and experiment is excellent. Characteristic curves for the steady‐state operation are deduced.

64 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the propagation delay between stages was a function of the operating frequency of SOS counter circuits, and that the change in propagation delay was associated with a change in the magnitude of a transient drain current.
Abstract: It was observed that during operation of SOS counter circuits, the propagation delay between stages was a function of the operating frequency. Further analysis proved the change in propagation delay to be associated with the change in the magnitude of a transient drain current. The origin of the transient current was found to lie in properties of the floating substrate. This paper discusses these properties and their effect on transistor operation, indlucing threshold voltage, drain current, rise and fall times, and propagation delay. The effect of states at the Si-sapphire interface is also described.

63 citations


Journal ArticleDOI
TL;DR: In this article, the transient and steady-state properties of a model system consisting of a collection of atoms interacting cooperatively and driven by a classical external field were analyzed, and numerical solutions for selected atomic expectation values were provided.
Abstract: We analyze the transient and steady-state properties of a model system consisting of a collection of atoms interacting cooperatively and driven by a classical external field. We obtain numerical solutions for selected atomic expectation values and suggest a steady-state scaling relation.

55 citations


Journal ArticleDOI
TL;DR: In this article, a set of curves and a number of useful approximate expressions for determining the small signal dynamic response of induction machines are presented for a wide range of operating conditions including variations in line frequency.
Abstract: Utilizing non-dimensional parameters based on the rotor transient time constant, a set of curves and a number of useful approximate expressions are presented for determining the small signal dynamic response of induction machines. These results permit rapid estimation of damping and oscillation frequency for a wide range of operating conditions including variations in line frequency. Stability and minimum damped operation are studied in detail and curves are presented to allow accurate determination of the operating condition, the degree of damping, and the oscillation frequency at the minimum damped operating point.

53 citations


Journal ArticleDOI
TL;DR: In this article, a mathematical representation of the state-plane switching boundary employed in a state-trajectory control law for dc-to-dc converters is derived. And several levels of approximation to the switching boundary equations are presented, together with an evaluation of the effects of nonideal operating characteristics of converter power stage components on the shape and location of the boundary and the behavior of a system controlled by it.
Abstract: Mathematical representations of a state-plane switching boundary employed in a state-trajectory control law for dc-to-dc converters are derived. Several levels of approximation to the switching boundary equations are presented, together with an evaluation of the effects of nonideal operating characteristics of converter power stage components on the shape and location of the boundary and the behavior of a system controlled by it. Digital computer simulations ions of d-to-dc converters operating in conjunction with each of these levels of control are presented and evaluated with respect to changes in transient and steady-state performance.

48 citations



Journal ArticleDOI
TL;DR: In this article, a 32-channel computer based data acquisition and processing system has been developed for use with the new type of transient cascade facility at Oxford, which is used for testing turbine blades and nozzle guide vanes at full-scale engine Reynolds and Mach numbers with correct wall-to-flow temperature ratios.
Abstract: A 32-channel computer based data acquisition and processing system em has been developed for use with the new type of transient cascade facility at Oxford. This is used for testing turbine blades and nozzle guide vanes at full-scale engine Reynolds and Mach numbers ers with correct wallto-flow temperature ratios. A novel technique for processing transient heat transfer data from thin film surface resistance thermometers has been developed. Measurements of surface ace pressure around blades, and of the upstream turbulence level have been made. The cascade and instrumentation are shown to have advantages both in cost and effectiveness over continuous running cascades.

Patent
12 May 1978
TL;DR: Power line transient suppressing circuits as mentioned in this paper use inductors in series w the load to reject or attenuate transients on the power line over a wider range of transients than with prior devices and also serve as inrush current limiters.
Abstract: Power line transient suppressing circuits which use inductors in series w the load to reject or attenuate transients on the power line over a wider range of transients than with prior devices, and also serve as inrush current limiters. Two unidirectional current circulating diode-inductor loop circuits eliminate the 60Hz voltage drop across the inductors. Normal operation is not affected by the circuits, but transients are rejected by the inductors.


Journal ArticleDOI
TL;DR: A pulsed, electrostatic probe data acquisition system, applicable to transient or noisy plasmas, is presented and the system digitally records a probe characteristic, and its first and second derivatives.
Abstract: A pulsed, electrostatic probe data acquisition system, applicable to transient or noisy plasmas, is presented. The system digitally records a probe characteristic, and its first and second derivatives. The latter are shown to be proportional to the projected electron energy distribution function, and the isotropic electron energy distribution function, respectively. The acquisition system and its experimental accuracy are discussed. Using the Lawrence Berkeley Laboratory 10-A neutral beam ion source, several examples demonstrating the systems application to transient plasmas are given.

Journal ArticleDOI
TL;DR: In this article, a 3D finite-difference method was used to predict the induced currents and charges on a complex object responding to an applied transient electromagnetic field in the presence of a lossy earth.
Abstract: Experimental charge and current measurements have recently been performed on an aircraft when it was exposed to the transient electromagnetic field of an electromagnetic-pulse (EMP) simulator. These new data allow a test of the predictive capabilities of the three-dimensional finite-difference method for realistic aircraft aircraftsimulator-test problems. Comparisons made between measurements and predictions show that the three-dimensional finite-difference technique provides reasonably accurate predictions for the induced currents and charges on a complex object responding to an applied transient electromagnetic field in the presence of a lossy earth.

Journal ArticleDOI
TL;DR: In this article, a flat vertical plate was assumed to be suddenly loaded internally with a constant and uniform flux while immersed in an extensive body of quiescent and unstratified fluid, and the partial differential equations describing the conservation of mass, momentum, and energy were solved in their time-dependent forms, using a finite difference technique.
Abstract: A flat vertical plate, of finite thickness and appreciable thermal capacity, was assumed to be suddenly loaded internally with a constant and uniform flux while immersed in an extensive body of quiescent and unstratified fluid. The partial differential equations describing the conservation of mass, momentum, and energy were solved in their time-dependent forms, using a finite-difference technique. The computed transient velocity and temperature fields are in good agreement with the results of previous integral and numerical analyses and with experimental data. The final steady-state profiles are also in good agreement with the similarity solution for the uniform surface flux condition. For some conditions, with plates of small thermal capacity, the transient temperature and velocity levels locally exceeded the final steady-state distributions.


Journal ArticleDOI
TL;DR: In this paper, a method is presented for determining the transient surface temperature of a solid when the temperature response as a function of time at an interior point within the solid is known.
Abstract: A method is presented for determining the transient surface temperature of a solid when the temperature response as a function of time at an interior point within the solid is known. The method employs approximate iterative techniques suitable for the solution of one-dimensional transient thermal conduction problems in homogeneous or composite solids with constant thermal properties. An example problem is solved using a linear technique and a least-squares approach. This iteration technique exhibits a high degree of accuracy, rapid convergence, and excellent stability. In addition, an analytical expression is developed that predicts the computed surface noise resulting from fluctuations in the input data.

Journal ArticleDOI
R.F. Pierret1
TL;DR: In this article, a procedure for rapidly and accurately deducing the generation lifetime from metaloxide-semiconductor capacitor C-t transient data is presented, explained, and illustrated.
Abstract: A procedure for rapidly and accurately deducing the generation lifetime from metal-oxide-semiconductor capacitor C-t transient data is presented, explained, and illustrated.

Patent
12 Jun 1978
TL;DR: In this paper, the magnitude of the pulse is limited to the threshold value of a selected breakdown device that is equally effective with voltage excursions of either polarity, and which includes means to reduce the high frequency content of the noise pulse and radically attenuate any tendency for oscillation.
Abstract: Suppression circuit for transient noise pulses in which the magnitude of the pulse is limited to the threshold value of a selected breakdown device that is equally effective with voltage excursions of either polarity, and which includes means to reduce the high frequency content of the noise pulse and radically attenuate any tendency for oscillation.

Journal ArticleDOI
TL;DR: In this paper, the transient behavior of unit-type HVDC convertors connected to isolated synchronous generators is analyzed using state space theory and a numerical solution suitable for digital computation is described.
Abstract: The transient behaviour of 'unit-type' schemes consisting of HVDC convertors connected to isolated synchronous generators is analysed using state space theory and a numerical solution suitable for digital computation is described. Examples of computed results are illustrated including normal and disturbed operating conditions. These show that 'unit-type' schemes can operate satisfactorily with or without A. C. harmonic filters.


Journal ArticleDOI
TL;DR: In this paper, the relative sensitivities of the active and reactive components of a harmonic field are considered as well as that of transient fields to changes in the resistivity and dimensions of a conducting body.
Abstract: The relative sensitivities of the active and reactive components of a harmonic field are considered as well as that of transient fields to changes in the resistivity and dimensions of a conducting body. It is shown that the active and reactive components of a harmonic field have different resolving capabilities and, as such, different signal/noise ratios. The resolving capabilities of time and frequency domain techniques are compared in both high and low frequency ends of the spectrum, as well as early and late stages of the transient. The useful signal and the “geologic noise” are approximated by two conducting bodies immersed in an otherwise nonconducting medium.

ReportDOI
01 Dec 1978
TL;DR: In this article, the fundamental fundamental of transient beam loading in electron-positron storage rings is reviewed, and the analysis is extended to include the transient behaviour of the cavity fields and reflected power between bunch passages.
Abstract: In this note the fundamental of transient beam loading in electron-positron storage rings will be reviewed. The notation, and some of the material, has been introduced previously. The present note is, however, more tutorial in nature, and in addition the analysis is extended to include the transient behaviour of the cavity fields and reflected power between bunch passages. Since we are not bound here by the rigid space limitations of a paper for publication, an attempt is made to give a reasonably coherent and complete discussion of transient beam loading that can hopefully be followed even by the uninitiated. The discussion begins with a consideration of the beam-cavity interaction in the ''single-pass'' limit. In this limit it is assumed that the fields induced in the cavity by the passage of a bunch have decayed essentially to zero by the time the next bunch has arrived. The problem of the maximum energy that can be extracted from a cavity by a bunch is given particular attention, since this subject seems to be the source of some confusion. The analysis is then extended to the ''multiple-pass'' case, where the beam-induced fields do not decay to zero between bunches, and to a detailedmore » consideration of the transient variation of cavity fields and reflected power. The note concludes with a brief discussion of the effect of transient beam loading on quantum lifetime.« less



Journal ArticleDOI
TL;DR: In this paper, it was shown by numerical simulation that in a transient stage trajectories in phase space are unstable also in the range of r in which a stable limit cycle exists.


Journal ArticleDOI
TL;DR: In this paper, the scaling theory of transient phenomena near the instability point is applied to analyze the transient behavior of laser radiation from the unstable state (i.e., no photon at the initial time).
Abstract: The general scaling theory of transient phenomena near the instability point proposed by one of the authors (M.S.) is applied to analyze the transient behavior of laser radiation from the unstable state (i.e., no photon at the initial time). The analytic results thus obtained by the scaling theory agree very well with the experimental results on the laser intensity and its fluctuation obtained by Arecchi and Degiogio. This gives a nice example of the general fluctuation-enhancement theorem proved by the scaling theory.