Dynamic accuracy of the electromagnetic flowmeter

1965 ◽  
Vol 20 (1) ◽  
pp. 142-147 ◽  
Author(s):  
M. F. O'Rourke
Keyword(s):  
Magnetic Field ◽  
Pulsatile Flow ◽  
Output Signal ◽  
Oscillatory Flow ◽  
Electromagnetic Flowmeter ◽  
Sine Wave ◽  
Dynamic Calibration ◽  
Phase Lag ◽  
Dynamic Accuracy ◽  
Sinusoidal Flow

Dynamic calibration of electromagnetic flowmeters was performed by resolving the output signal when sinusoidal flow of known characteristics was pumped through the probe. In two instruments amplitude and phase were found to be frequency dependent in the range 0–20 cycle/sec; the magnitude of these effects was not insignificant as many have assumed. In a sine wave instrument using a variety of probes, both amplitude and phase increased linearly with frequency: the former increasing by 0.57% per cycle per second, the latter by 3.6° per cycle per second. In the square wave flowmeter at 0 damping, amplitude decreased significantly above 5 cycle/sec, while phase lag increased by 4.9° per cycle per second. These effects are concluded to be due to the output filtering network. In the sine wave instrument it was demonstrated that magnetic field nonuniformity within the probe did not alter the accuracy in recording steady or oscillatory flow. It was thus possible to construct a small short flowmeter probe having narrow electromagnet coils, and it is expected that this probe should cause minimal interference to pulsatile flow patterns. magnetic fields flowmeter probes; frequency-response flowmeter Submitted on April 16, 1964

Frequency response of electromagnetic flowmeters

1964 ◽  
Vol 19 (6) ◽  
pp. 1209-1211 ◽  
Author(s):  
Urs Gessner ◽  
Derek H. Bergel
Keyword(s):  
Frequency Response ◽  
Electromagnetic Flowmeter ◽  
Sine Wave ◽  
Phase Lag ◽  
Simple Method ◽  
Electrical Circuits ◽  
Square Wave ◽  
Significant Difference ◽  
Electrical Calibration

A comparison was made between hydraulic and electrical determination of the frequency response of two types of electromagnetic flowmeter. The output of the square-wave meter tested was reduced in amplitude by 10% at 7 cycles/sec; it lagged behind the input by approximately 4.5°/cycle per second. The output of the gated sine-wave meter was reduced by 10% at 24 cycles/sec and the phase lag was approximately 2.2°/cycle per second. No significant difference was detected between the results of either method of calibration. The frequency response of these instruments is determined by the characteristics of their electrical circuits. It is recommended that each user calibrate his own instrument; a simple method of electrical calibration is described. Since the frequency response of either meter is relatively poor, flow records obtained with them must be appropriately corrected. methods of calibration Submitted on March 9, 1964

A rapid technique for dynamic calibration of electromagnetic flowmeters

1982 ◽  
Vol 53 (1) ◽  
pp. 294-296 ◽  
Author(s):  
R. D. Hill
Keyword(s):  
Digital Computer ◽  
Oscillatory Flow ◽  
Fourier Transforms ◽  
Dynamic Calibration ◽  
Phase Lag ◽  
Flow Probe ◽  
Square Wave ◽  
Rapid Technique ◽  
A New Technique ◽  
Transistor Circuit

A new technique for the dynamic calibration of electromagnetic flowmeters has been developed that uses a simple transistor circuit and is suitable for both sine- and square-wave flowmeters. The magnet current is amplitude modulated using a square wave at a frequency of 1 Hz to provide a suitable input to the flowmeter. This input simulates the input that would have been generated is a square-wave oscillatory flow had been passed through a flow probe. The modulating square wave together with the square wave from the flowmeter output are sampled using a digital computer, and comparison of the Fourier transforms of the two waveforms yields a calibration of amplitude attentuation and phase lag for frequencies up to 50 Hz. The technique is very fast and thus allows multiple determinations of the calibration, which in turn lead to a more accurate calibration that has been achieved by other methods. The calibration of a Statham SP2202 flowmeter is presented providing an example of the technique.

ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Simple Model ◽  
Critical Frequency ◽  
Optical Methods ◽  
Phase Lag ◽  
Rotating Magnetic Fields ◽  
Mr Fluids ◽  
Small Angle Light Scattering ◽  
The Magnetic Field

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.

Pattern of blood flow in the pulmonary veins of the dog

1965 ◽  
Vol 20 (6) ◽  
pp. 1118-1128 ◽  
Author(s):  
Eugene Morkin ◽  
John A. Collins ◽  
Harold S. Goldman ◽  
Alfred P. Fishman
Keyword(s):  
Blood Flow ◽  
Pulmonary Circulation ◽  
Pulmonary Veins ◽  
Electromagnetic Flowmeter ◽  
Sine Wave ◽  
Left Ventricular ◽  
Mean Flow ◽  
Venous Flow ◽  
Pulmonary Venous Flow ◽  
Atrial Contraction

The pattern of blood flow in the large pulmonary veins was studied in dogs by chronic implantation of sine-wave electromagnetic flowmeters and cineangiographic observations. These revealed that: 1) pulmonary venous flow is continuous and pulsatile with peak rate of flow of approximately twice the mean flow; 2) the initial rapid increase in venous flow occurs 0.10 sec after the onset of ventricular systole, reaching a peak at the time of closure of the A-V valves; 3) left atrial contraction produces a fleeting slowing or reversal of flow; and 4) respiratory variations in pulmonary venous flow follow those in pulmonary arterial flow, beat by beat. The genesis of phasic pulmonary venous flow was investigated by analysis of pressure and flow curves from the two sides of the heart, by consideration of the energy required for left ventricular filling, and by reconstruction of the pulmonary venous flow pulse using a mathematical model of the pulmonary circulation. These three lines of evidence are consistent in indicating that the transmitted right ventricular pressure is the major determinant of the pulmonary venous flow pattern in the dog. pulsatile pulmonary venous flow; pulmonary venous flow; pulmonary circulation; ventricular suction; respiration on pulmonary circulation; pulmonary venous angiography; pulmonary veno-atrial junctions; electromagnetic flowmeter; cineangiography Submitted on November 16, 1964

scholarly journals Magnetic field on surface waves propagation in gravitational thermoelastic media with two temperature and initial stress in the context of three theories

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 285-299
Author(s):  
Jamel Bouslimi ◽  
Sayed Abo-Dahab ◽  
Khaled Lotfy ◽  
Sayed Abdel-Khalek ◽  
Eied Khalil ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surface Waves ◽  
Initial Stress ◽  
Half Space ◽  
Generalized Thermoelasticity ◽  
Phase Lag ◽  
Mathematical Methods ◽  
Numerical Work ◽  
Suitable Material ◽  
Two Temperature

In this paper is investigating the theory of generalized thermoelasticity under two temperature is used to solve boundary value problems of 2-D half-space its bound?ary with different types of heating under gravity effect. The governing equations are solved using new mathematical methods under the context of Lord-Shulman, Green-Naghdi theory of type III (G-N III) and the three-phase-lag model to inves?tigate the surface waves in an isotropic elastic medium subjected to gravity field, magnetic field, and initial stress. The general solution obtained is applied to a spe?cific problem of a half-space and the interaction with each other under the influence of gravity. The physical domain by using the harmonic vibrations is used to obtain the exact expressions for the Waves velocity and attenuation coefficients for Stoneley waves, Love waves, and Rayleigh waves. Comparisons are made with the results between the three theories. Numerical work is also performed for a suitable material with the aim of illustrating the results. The results obtained are calculated numerical?ly and presented graphically with some comparisons in the absence and the presence the influence of gravity, initial stress and magnetic field. It clears that the results ob?tained agree with the physical practical results and agree with the previous results if the gravity, two temperature, and initial stress neglect as special case from this study.

scholarly journals Magnetism of the He-weak star HR 2949

2010 ◽  
Vol 6 (S272) ◽  
pp. 210-211
Author(s):  
Thomas Rivinius ◽  
Gregg A. Wade ◽  
Richard H. D. Townsend ◽  
Matthew Shultz ◽  
Jason H. Grunhut ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Line Profile ◽  
Equivalent Width ◽  
Rotational Line ◽  
Phase Lag ◽  
Abundance Patterns ◽  
Weak Star ◽  
Hydrogen Lines

AbstractA magnetic field and rotational line profile variability (lpv) is found in the He-weak star HR 2949. The field measured from metallic lines varies in a clearly non-sinusoidal way, and shows a phase lag relative to the morphologically similar He i equivalent width variations. The surface abundance patterns are strong and complex, and visible even in the hydrogen lines.

scholarly journals Dynamic Sensitivity and Noise Floor of a Bonded Magneto(Elasto)Electric Laminate for Low Frequency Magnetic Field Sensing under Strain Modulations

2015 ◽  
Vol 644 ◽  
pp. 236-239 ◽  
Author(s):  
Xin Zhuang ◽  
Marc Lam Chok Sing ◽  
Christophe Dolabdjian ◽  
Y. Wang ◽  
P. Finkel ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Output Signal ◽  
Low Frequency ◽  
Mechanical Impedance ◽  
Intrinsic Noise ◽  
Noise Performance ◽  
Noise Floor ◽  
Frequency Magnetic Field ◽  
Field Sensing ◽  
Magnetic Field Sensing

The intermediated strain can convert a magnetic field to an electric output signal in a magnetostrictive-piezoelectric layered composite via three parameters: the magnetoelastic coupling, the piezoelastic coupling and the mechanical impedance. These three parameters are dominated respectively by the magnetostrictive coefficient, the piezoelectric coefficient and the mean flexibility of material in the composite. Focusing on these three parameters, many investigations on the ME enhancement have been carried out by choosing the correct material or by adjusting the ratio between the two phases in the composite [4]. Thereafter, the noise performance of ME laminates has been studied for applications as a magnetic sensor. In the last several years, the intrinsic noise sources for both the composite and the amplifier circuit have been mathematically modeled and experimentally characterized. The passively sensed signal can be amplified by either a voltage or a charge method. Furthermore, the noise contributions from the detection electronics were also integrated in the noise performance analysis [5]. According to these studies, dielectric dissipation in the piezoelectric phase is the main contribution to the noise floor for low-frequency magnetic field sensing even though the equivalent current noise source from the electronics induce fluctuations in the output signal of the low-frequency charge detection as well [6].

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