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Papers by Zdzisław Szczepanik

Electric field distribution in impedance cell designed according to the assumptions of van der Pa... more Electric field distribution in impedance cell designed according to the assumptions of van der Pauw method of electrical conductivity measurement has been used. Particularly the effect of electrode-electrolyte solution interface (EESI) on electric field distribution and conductance cell constants has been studied. It has been found that the EESI of current carrying electrodes influences cell field distribution. It has been

An equivalent four-terminal model of an impedance tomography sensor in the measuring channel is p... more An equivalent four-terminal model of an impedance tomography sensor in the measuring channel is presented. The frequency dependence of the potential difference measured be- tween voltage electrodes of the sensor is analyzed theoretically and compared with the results of experiments carried out in the range 10 Hz-20 kHz. A good agreement is found. Results of the analysis revealed the frequency range of the measuring signal (10 Hz-5 kHz in the considered case) for which the potential difference is constant or varies insignificantly. At higher frequencies (more than 5 kHz), however, an evident variability was found—the higher the frequency, the higher potential difference. This results from the impedance characteristic of the tomography system including interfacial layer impedances, parasitic capacitances (particularly between the electrodes of the sensor) as well as signal source and voltmeter parameters. Analysis of the frequency characteristic of any individual tomography system is ...

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1988

A number of advantages can be achieved when single increment methods are introduced in conductome... more A number of advantages can be achieved when single increment methods are introduced in conductometric measurements of the concentration of electrolytic solutions. The cell constant and the conductivity-concentration curve do not need be known; temperature correction becomes unnecessary; very high and low concentrations can be measured accurately; and a very small volume of sample is sufficient. A set of such methods has been proposed and discussed, and suitable formulae are given. Theoretical considerations have been verified experimentally.

Quality Measurement: The Indispensable Bridge between Theory and Reality (No Measurements? No Science! Joint Conference - 1996: IEEE Instrumentation and Measurement Technology Conference and IMEKO Technical Committee 7. Conference Proceedings, 1996

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IEEE Transactions on Instrumentation and Measurement, 1997

It appears that a four-electrode conductance cell designed and used according to the van der Pauw... more It appears that a four-electrode conductance cell designed and used according to the van der Pauw method can be applied for the absolute determination of the electrolytic conductivity of solutions with an accuracy comparable with that of the secondary standards for this quantity. Therefore there may be a possibility of avoiding the use of those standards in some cases. The results of the experimental investigation of a prototype model of the cell of this type, carried out by the authors, are consistent with the theoretical considerations and computer modeling. An absolute determination of electrolytic conductivity has been made for 0.01 and 0.1 M KCl solutions, with an overall uncertainty lower than 0.4%.

... for e?cample in impedance tomography [3] as well as for EESI modelling [4] but there are no p... more ... for e?cample in impedance tomography [3] as well as for EESI modelling [4] but there are no papers treating both problems together. ... Ths in turn means that the possible field dstribution distortion in the FEM model should be higher than that in the actual cell.. ...

Acta of Bioengineering and Biomechanics, 2016

Some basic problems related to measurements of electrical impedance of biological objects (bioimp... more Some basic problems related to measurements of electrical impedance of biological objects (bioimpedance) have been presented in this paper. Particularly problems arising from impedance occurring at the sensor-tissue interface (interfacial impedances) in contact measuring methods have been discussed. The influence of finite values of impedances of the current source and voltage measuring device has also been taken into consideration. A model of the impedance sensor for the four-electrode measurement method containing the interfacial, source and measuring device impedances has been given and its frequency characteristics obtained by the computer simulation have been presented. The influence of these impedances on the shape of frequency characteristic of the sensor model has been discussed. Measurements of bioimpedance of healthy and anomalous soft tissues have been described. Some experimental results, particularly the frequency characteristics of bioimpedance, have been shown. The pr...

Acta of bioengineering and biomechanics / Wrocław University of Technology, 2016

Sensors and Actuators A: Physical, 2007

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IEEE Transactions on Instrumentation and Measurement, 2003

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IEEE Transactions on Instrumentation and Measurement, 2000

Since 1979, he has been a Senior Lecturer of Measurement Systems. His research interests include ... more Since 1979, he has been a Senior Lecturer of Measurement Systems. His research interests include application of the electrical impedance measurements, impedance spectroscopy and tomography, for the investigations of the structure of two-phase subjects.

The user has requested enhancement of the downloaded file. All in-text references underlined in b... more The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. Some basic problems related to measurements of electrical impedance of biological objects (bioimpedance) have been presented in this paper. Particularly problems arising from impedance occurring at the sensor–tissue interface (interfacial impedances) in contact measuring methods have been discussed. The influence of finite values of impedances of the current source and voltage measuring device has also been taken into consideration. A model of the impedance sensor for the four-electrode measurement method containing the interfacial, source and measuring device impedances has been given and its frequency characteristics obtained by the computer simulation have been presented. The influence of these impedances on the shape of frequency characteristic of the sensor model has been discussed. Measurements of bioimpedance of healthy and anomalous soft tissues have been described. Some experimental results, particularly the frequency characteristics of bioimpedance, have been shown. The presented results of measurement show that bioimpedance can be a valuable source of information about the tissues, so measurement of bioimpedance can be a useful supplement to other medical diagnostic methods.

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1988

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IEEE Transactions on Instrumentation and Measurement, 1997

Acta of Bioengineering and Biomechanics, 2016

Acta of bioengineering and biomechanics / Wrocław University of Technology, 2016

Sensors and Actuators A: Physical, 2007

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IEEE Transactions on Instrumentation and Measurement, 2003

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IEEE Transactions on Instrumentation and Measurement, 2000