The Frequency Response of Pneumatic Lines

1967 ◽  
Vol 89 (2) ◽  
pp. 371-378 ◽  
Author(s):  
J. T. Karam ◽  
M. E. Franke
Keyword(s):  
Frequency Response ◽  
High Frequency ◽  
Signal Frequency ◽  
Frequency Range ◽  
Frequency Model ◽  
Resonant Frequencies ◽  
Frequency Dependent ◽  
Amplitude Frequency Response ◽  
Theoretical Predictions ◽  
Response Transfer

The amplitude frequency response (transfer gain curve) of 0.170-in-ID blocked pneumatic lines of the type used in fluidic systems was experimentally determined. Several lengths (20 ft and less) of tubing at several mean pressures (10 to 40 psig) were studied over the frequency range of 1-1000 cps. The electric-pneumatic analogy was used to develop theoretical predictions of the gain curves. Correlation with experiment showed that a frequency-dependent resistance and a frequency-dependent conductance were required in the analogy when the signal frequency was somewhat greater than a characteristic frequency of the line. A high-frequency model, based on the work of Nichols, was developed; it predicted the resonant gains within 2 db and the resonant frequencies within 10 percent.

High-Frequency Model of the Power Transformer Based on Frequency-Response Measurements

2015 ◽  
Vol 30 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Dalibor Filipovic-Grcic ◽  
Bozidar Filipovic-Grcic ◽  
Ivo Uglesic
Keyword(s):  
Frequency Response ◽  
High Frequency ◽  
Power Transformer ◽  
Frequency Model

Permeability and borehole Stoneley waves: Comparison between experiment and theory

Geophysics ◽  
1989 ◽  
Vol 54 (1) ◽  
pp. 66-75 ◽  
Author(s):  
Kenneth W. Winkler ◽  
Hsui‐Lin Liu ◽  
David Linton Johnson
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Theoretical Models ◽  
Oil Field ◽  
Stoneley Wave ◽  
Biot Theory ◽  
Frequency Dependent ◽  
Low Frequencies ◽  
High Frequencies ◽  
Theoretical Predictions

We performed laboratory experiments to evaluate theoretical models of borehole. Stoneley wave propagation in permeable materials. A Berea sandstone and synthetic samples made of cemented glass beads were saturated with silicone oils. We measured both velocity and attenuation over a frequency band from 10 kHz to 90 kHz. Our theoretical modeling incorporated Biot theory and Deresiewicz‐Skalak boundary conditions into a cylindrical geometry and included frequency‐dependent permeability. By varying the viscosity of the saturating pore fluid, we were able to study both low‐frequency and high‐frequency regions of Biot theory, as well as the intermediate transition zone. In both low‐frequency and high‐frequency regions of the theory, we obtained excellent agreement between experimental observations and theoretical predictions. Velocity and attenuation (1/Q) are frequency‐dependent, especially at low frequencies. Also at low frequencies, velocity decreases and attenuation increases with increasing fluid mobility (permeability/viscosity). More complicated behavior is observed at high frequencies. These results support recent observations from the oil field suggesting that Stoneley wave velocity and attenuation may be indicative of formation permeability.

Mechanical Response of the Lungs at High Frequencies

1978 ◽  
Vol 100 (2) ◽  
pp. 57-66 ◽  
Author(s):  
J. J. Fredberg ◽  
A. Hoenig
Keyword(s):  
Efficient Method ◽  
High Frequency ◽  
Input Impedance ◽  
Mechanical Response ◽  
Airway Wall ◽  
Frequency Range ◽  
Resonant Frequencies ◽  
High Frequencies ◽  
Branching Networks ◽  
Adult Humans

We put forward an efficient method for computing the input impedance of complex asymmetrically branching duct networks, and apply this method to simulation of the dynamic response of the lungs of normal adult humans in the frequency range extending to 10,000 Hz. The results indicate that the response of comparable symmetric and asymmetric branching networks differ at high frequency (> 2 kHz in air), and that the airway wall response is an important factor in determining system damping and resonant frequencies.

scholarly journals Measurement -based electrical parameters of power transformers for Frequency Response Analysis interpretation - Part I: Core analysis

2017 ◽  
Vol 20 (K3) ◽  
pp. 5-10
Author(s):  
Khoi Dinh Anh Pham
Keyword(s):  
Frequency Response ◽  
Power Transformers ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Frequency Range ◽  
Electrical Parameters ◽  
Efficient Tool ◽  
Frequency Dependent ◽  
New Approach ◽  
The Core

Although the standard Frequency Response Analysis (FRA) test has been approved as an efficient tool to diagnose mechanical failures in power transformers, the demand to interpret FRA traces in practical and physical way is still requested. That means physical electrical parameters of transformers should be determined reasonably based on real measurements and afterwards are applicable for the interpretation. For purpose of FRA interpretation in practical manner, electrical parameters of power transformers in a physical equivalent circuit should be determined. As a first step, the paper introduces a new approach in determining frequency dependent core impedances of a distribution transformer based on the combination of circuit analysis of a duality-based model, measurements of driving-point impedances and experimental formulas. From that, two important contributions can be drawn. Firstly, frequency dependent core impedances are ready as available components in the circuit for FRA interpretation in broad frequency range. Secondly, the core parameters could be useful indicators for detecting relevant failures in cases there is no more failure on transformer windings.

Study on the Stepping Identification Arithmetic for Broadband EMP Test System

2013 ◽  
Vol 475-476 ◽  
pp. 643-647
Author(s):  
Ting An ◽  
Xue Hua Jiang
Keyword(s):  
Frequency Domain ◽  
High Frequency ◽  
Low Frequency ◽  
Test System ◽  
Practical Application ◽  
Frequency Range ◽  
Frequency Model ◽  
Building Model ◽  
Poles And Zeros ◽  
Identification Model

In order to overcome the limitation of common methods in modeling test system of broadband electromagnetic pulse (EMP), the paper provided a stepping identification arithmetic to solve the problem of building model in whole frequency range. It obtained low-frequency model and high-frequency model respectively in low-frequency domain and high-frequency domain by identification using import signal and output signal measured by test, it obtained the identification model of the test system by connecting the low-frequency model and high-frequency model, the model was simplified by offsetting adjacent poles and zeros. The results of simulation and test show that the papers method can reflect the dynamic characteristic of the system in whole frequency range, and it is feasible in practical application.

The Frequency Response of Pneumatic Lines With Branching

1973 ◽  
Vol 95 (2) ◽  
pp. 194-196 ◽  
Author(s):  
V. K. Ravindran ◽  
J. R. Manning
Keyword(s):  
Frequency Response ◽  
Three Dimensional ◽  
Experimental Results ◽  
Signal Frequency ◽  
Small Signal ◽  
Dimensional Effects ◽  
Constant Area ◽  
Theoretical Predictions

Some experimental results are presented for amplitude and phase of small signal frequency response of pneumatic lines in configurations with branching. The recent data of Franke, Malanowski, and Martin [1] is extended in two areas: 1 Phase as well as amplitude measurements were made. 2 Stepped and conical branches were studied as well as constant area branches. Agreement is good with theoretical predictions based on the Iberall-Nichols-Brown model [2, 3, 4] and a simple continuity model for branch junctions. Three-dimensional effects at junctions are apparently not significant for the small amplitudes (less than 0.1 psi) and range of frequencies (100 to 1000 Hz) studied.

scholarly journals Measurement-based electrical parameters of power transformers for Frequency Response Analysis interpretation-Part II: Winding Part II: Winding analysis

2017 ◽  
Vol 20 (K3) ◽  
pp. 11-17
Author(s):  
Khoi Dinh Anh Pham
Keyword(s):  
Frequency Response ◽  
Diagnostic Testing ◽  
Power Transformers ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Frequency Range ◽  
Electrical Parameters ◽  
Frequency Dependent ◽  
The Core ◽  
Zero Sequence

For a practical Frequency Response Analysis (FRA) interpretation applicable to power transformers, frequency dependent electrical parameters of the core and windings in broad frequency range should be identified through non-destructive measurements. Since the core parameters are determined in Part I, electrical parameters of windings (resistances, capacitances) and leakage paths surrounding windings (leakage/zero-sequence impedances) of a distribution transformer will be discussed in this paper. Due to the fact that most parameters associated with the windings currently can only be measured at or around power frequency through diagnostic testing methods, the practical parameter-based FRA interpretation is not possible. To deal with this problem, the paper proposes a new approach based on the combination of different measured driving-point impedances and relevant analysis of the duality-based equivalent circuit in determining frequency dependent parameters associated with transformer windings. Results show that the physical FRA interpretation can be reasonable obtained for the test transformer in low and medium frequency range.

scholarly journals The effects of frequency response smoothness and high‐frequency range on speech intelligibility in noise

1981 ◽  
Vol 70 (S1) ◽  
pp. S108-S108
Author(s):  
Steven P. Bornstein ◽  
Kenneth J. Randolph ◽  
Antonia Maxon ◽  
Thomas Giolas
Keyword(s):  
Frequency Response ◽  
High Frequency ◽  
Speech Intelligibility ◽  
High Frequency Range ◽  
Frequency Range
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