Theoretical estimate of the dynamic characteristics of an electromagnetic flow transducer

1980 ◽  
Vol 23 (12) ◽  
pp. 1132-1134
Author(s):  
A. V. Pavlov
Keyword(s):  
Dynamic Characteristics ◽  
Theoretical Estimate ◽  
Flow Transducer ◽  
Electromagnetic Flow

Effect of implant duration on in vivo sensitivity of electromagnetic flow transducers

1979 ◽  
Vol 236 (3) ◽  
pp. H508-H512 ◽  
Author(s):  
C. A. Astley ◽  
A. R. Hohimer ◽  
R. B. Stephenson ◽  
O. A. Smith ◽  
F. A. Spelman
Keyword(s):  
Rhesus Monkeys ◽  
Initial Period ◽  
Dialysis Tubing ◽  
Flow Transducer ◽  
Electromagnetic Flow ◽  
Femoral Arteries ◽  
In Vitro Sensitivity

Twenty-three electromagnetic flow transducers with lumen diameters of 3.5-6.0 mm were implanted in rhesus monkeys and baboonss for 12 h to 120 days. Each flow transducer was calibrated 1) in vitro on dialysis tubing with saline before implantation, 2) in vivo the last day of the implant period, and 3) again in vitro after the flow transducer was recovered. Three other flow transducers were implanted on femoral arteries of baboon just central to an arteriovenous Silastic shunt, and were calibrated in vivo daily for 23-47 days. In vitro sensitivity was not affected by implant durations of up to 120 days. In vivo sensitivity fluctuated unpredictably for the first 3-4 wk of implant, after which it followed a systematic course that depended on the lumen size. In vivo sensitivity at any time during implant (after the initial period) could be accurately predicted by knowing either the in vitro sensitivity or the terminal in vivo sensitivity.

Measurement of umbilical blood flow in fetal lambs in utero

1975 ◽  
Vol 39 (6) ◽  
pp. 1056-1059 ◽  
Author(s):  
W. Berman ◽  
R. C. Goodlin ◽  
M. A. Heymann ◽  
A. M. Rudolph
Keyword(s):  
Blood Flow ◽  
In Utero ◽  
Flow Measurements ◽  
Flow Transducer ◽  
Descending Aorta ◽  
Electromagnetic Flow ◽  
Umbilical Blood ◽  
The Common ◽  
Umbilical Blood Flow ◽  
Umbilical Arteries

We continuously measured umbilical blood flow in fetal lambs in utero by placing an electromagnetic flow transducer around the common umbilical artery. Umbilical arteries originate from a short common segment as the terminal branches of the descending aorta. This segment was isolated by a retroperitoneal surgical approach and encircled with a specially constructed electromagnetic flow transducer. Catheters were also placed in fetal vessles to monitor pressure and derive flow values by the radionuclide-labeled microsphere technique. The fetus and ewe were allowed to recover for two days before studies were performed. Average umbilical blood flow obtained in 11 animals with the transducer was 199 ml/kg per min. In seven animals flow measurements obtained with the transducer were compared with those derived from microsphere injections. Paired measurements varied by an average of only 5.3%. This technique makes possible the accurate and instantaneous measurement of umbilical blood flow in fetal lambs in utero over a prolonged period.

Battery Powered Electromagnetic Flow Meter with Locally Shrunk Measurement Pipe

2014 ◽  
Vol 568-570 ◽  
pp. 315-319
Author(s):  
Tie Jun Liu ◽  
Min Zhou
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Flow Meter ◽  
Flow Transducer ◽  
Electromagnetic Flow ◽  
Transducer Design ◽  
Field Excitation ◽  
Electromagnetic Flow Meter ◽  
The Magnetic Field ◽  
Excitation Circuit

Based on computer simulation, a new measurement pipe design with locally shrunk cross section is proposed for electromagnetic flow transducer. The efficiency of the magnetic field excitation circuit is effectively enhanced. The sensitivity of the transducer is increased. The transducer design is adopted in a battery powered electromagnetic flow meter prototype to reduce the power consumption. The prototype was tested. The feasibility of the proposed design was proved.

Advantages of continuous measurement of cardiac output 24 h a day

1995 ◽  
Vol 269 (2) ◽  
pp. H696-H703 ◽  
Author(s):  
J. P. Montani ◽  
H. L. Mizelle ◽  
B. N. Van Vliet ◽  
T. H. Adair
Keyword(s):  
Cardiac Output ◽  
Continuous Measurement ◽  
Peripheral Resistance ◽  
Computer Assisted ◽  
Flow Transducer ◽  
Electromagnetic Flow ◽  
Coefficients Of Variation ◽  
Experimental Protocols ◽  
Day By Day

To test the hypothesis that continuous measurement of cardiac output 24 h a day would provide a better day-by-day reproducibility of the daily average cardiac output than acute measurements, we developed a computer-assisted method to monitor cardiac output continuously using an electromagnetic flow transducer. Because the diastolic aortic flow, which is used as a zero-flow reference, can drift significantly with electromagnetic flow probes, automatic tracking of the diastolic flow baseline was considered essential for long-term measurements. To accomplish this, the analog pulsatile flow signal was digitally converted and processed by an IBM PC to correct for signal drift on a beat-per-beat basis. Using this computerized system in 19 chronically instrumented dogs, we compared the values of cardiac output during 5 consecutive control days, measured either for 20 h each day (allowed 4 h for special care) or for 30 min in the morning when the trained dogs were required to lie quietly in their cages. The results show that the coefficient of variation of the five daily averages in cardiac output for each individual dog was three times smaller when cardiac output was measured 20 h each day (2.9 +/- 0.3 vs. 9.7 +/- 1.0%). Whole-day coefficients of variation were also smaller for mean arterial pressure, heart rate, stroke volume, and total peripheral resistance. Because of this greater day-by-day reproducibility, continuous monitoring of cardiac output is likely to be more sensitive to small changes in cardiac output induced by experimental protocols.

De-Noising Signal of Electromagnetic Flowmeter Based on Wavelet Transform

2012 ◽  
Vol 220-223 ◽  
pp. 2144-2149
Author(s):  
Tie Jun Liu ◽  
Yin Jia Chen
Keyword(s):  
Electromagnetic Flowmeter ◽  
Haar Wavelet ◽  
Experimental Result ◽  
Wavelet Filter ◽  
Flow Transducer ◽  
Electromagnetic Flow ◽  
Filter Technique ◽  
Simulation Based ◽  
Effectiveness And Efficiency ◽  
Electromagnetic Flow Meter

A Software filter technique based on Haar wavelet is proposed for effectively suppressing the noise components in the signal of electromagnet flow transducer. It is proved with computer simulation based on MATLAB Wavelet Toolbox that the proposed filter technique is well matched with the feature of the signal of the electromagnetic flow transducer in effectiveness and efficiency. A prototype flowmeter was developed based on the proposed technique, experimental result with the prototype shows that the proposed Haar wavelet filter technique is well suitable for de-noising the signal of electromagnetic flow meter.

Theoretical model construction and structure optimization of electromagnetic flow transducer based on neural network

2019 ◽  
Vol 37 (3) ◽  
pp. 3489-3498 ◽  
Author(s):  
Yingwei Li ◽  
Yuntong Yang ◽  
Shaoqing Ma ◽  
Lei Li ◽  
Yanjun Wang ◽  
...  
Keyword(s):  
Neural Network ◽  
Theoretical Model ◽  
Structure Optimization ◽  
Model Construction ◽  
Flow Transducer ◽  
Electromagnetic Flow

Invited PaperTemperature dependence of SiGe HBT static and dynamic characteristics

1998 ◽  
Vol 08 (PR3) ◽  
pp. Pr3-81-Pr3-86
Author(s):  
F. Aniel ◽  
N. Zerounian ◽  
A. Gruhle ◽  
C. Mähner ◽  
G. Vernet ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Static And Dynamic Characteristics ◽  
Sige Hbt
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