2023 International Workshop on Impedance Spectroscopy (IWIS)
This paper presents an inductive measuring system using a two-pancake coil setup for monitoring t... more This paper presents an inductive measuring system using a two-pancake coil setup for monitoring the electromagnetic properties of steel sheets. An experimental setup was developed to perform measurements on cooling sheet metal samples during real structural transformations. Additional to the experiments with hot steel sheets, a simulation in COMSOL Multiphysics was used to validate the measurement results. The experiments conducted with the cooling material confirmed the suitability of the measurement system for the application described. The results obtained in this work show that by evaluating the phase shift between the exciting magnetic field H and the induction B, the structural transformation can be reliably monitored. In this work, a phase shift of 2 degrees was measured when a steel sheet was cooled by about 200 degrees Celsius.
ABSTRACT The bipolar transurethral resection is a further development of monopolar transurethral ... more ABSTRACT The bipolar transurethral resection is a further development of monopolar transurethral resection, being the gold standard in surgical treatment of prostate and bladder diseases. To create the metrological basis for understanding of electrical and physical processes during bipolar transurethral resection an experimental set-up to visualize spatial potential distribution around bipolar devices was developed. A hardware based signal conditioning and specific undersampling are presented as data acquisition methods for a sampling rate up to 1 MS/s. These methods are compared with the possibilities of a high speed data acquisition card. For more than four measuring channels and depending on the output bandwidth of the electrosurgical generator either hardware based signal conditioning or specific undersampling is suggested.
ABSTRACT In the field of magnetic inductance tomography,signal processing is a real challenge. Th... more ABSTRACT In the field of magnetic inductance tomography,signal processing is a real challenge. This is due to the divergent nature of magnetic fields. The sensitivity, i.e. the change in the receiving signal by means of an electrically conductive sample in a measuring volume depends strongly on the positioning of the sample. Objects that are located near the transmitting or receiving coils are very well locatable, where objects in larger distance are hard to detect. In this paper an approach is presented that improves the topology of the magnetic fields in the ”magnetic induction tomography” (MIT) by changing geometric constructions and current patterns of coils so far, as to allow a sharper localization of objects within the space. The aim is to level the distribution of the sensitivity in the measuring volume, so that electrically conductive objects with a larger distance between transmitting and receiving unit can be detected with almost the same signal intensity as objects close to the transmitting and receiving unit. The simulation tool Comsol is used for the geometric modeling making a finite element analysis (FEA). The subsequent signal processing and analysis of the simulation results are implemented in Matlab. Within this FEA the coil geometries and current patterns are changed numerically, so that the minimum object size, that is still detectable, is, compared to the known MIT, reduced and the sensitivity of the system is improved. To validate the simulation in Comsol c , first simulation results are compared with analytical models and analyses.
2009 6th International Multi-Conference on Systems, Signals and Devices, 2009
ABSTRACT Fat content of liver is an essential parameter to decide whether a liver is suitable for... more ABSTRACT Fat content of liver is an essential parameter to decide whether a liver is suitable for transplantation or not. The determination of fat content is often challenging and usually there is not enough time to bring a specimen to a pathologic laboratory. That is why transplantation clinics need a technique to measure the fat content of a graft. In this paper the theoretical basics and an existing laboratory setup are presented.
IEEE Transactions on Instrumentation and Measurement, 2014
ABSTRACT To analyze the electric field around bipolar resectoscopes, used in urology, in terms of... more ABSTRACT To analyze the electric field around bipolar resectoscopes, used in urology, in terms of reasons for late complications after a surgical treatment a flexible multielectrode system was developed to measure the 3-D potential distribution. A high spatial resolution is achieved with the least possible individual measurements under the conditions of a quasi-static electric field. A flexible arrangement and positioning of the measuring points in the vertical direction of the experimental environment enable an adjustable spatial resolution and the selection of the region of interest. The existing influence of the multielectrode system on the measuring results is described and a correction method is presented to achieve significant results. Thus, the multielectrode system is usable for a comparative study of bipolar resectoscopes varying in the arrangement of resection and return electrode.
ABSTRACT Bipolar electrosurgical systems are used for the treatment of benign prostatic hyperplas... more ABSTRACT Bipolar electrosurgical systems are used for the treatment of benign prostatic hyperplasia (BPH) in urology. In order to analyse electrothermal processes during surgery the power loss density distribution around a bipolar resectoscope is calculated out of the measured potential distribution in isotonic saline solution ex situ. During further analysis power loss density values act as input for the Penne's bioheat equation. To achieve results, which are as realistic as possible, a method to obtain power loss density values, depending on the observed tissue or medium in the operating field, is presented. Applying this method, the power loss density distribution in isotonic saline solution at 25 °C is compared to the distribution calculated for the average conductivity of biological tissue in the region of interest.
Die steigenden Anforderungen an den Umweltschutz bei möglichst niedrigen Kosten betreffen auch di... more Die steigenden Anforderungen an den Umweltschutz bei möglichst niedrigen Kosten betreffen auch die öffentlichen Kanalnetze und Kläranlagen. Speziell die Kanalnetze sind über Jahrzehnte gewachsen, ohne dass kostengünstig eine genaue Bilanz ihrer Leistungsfähigkeit bis in ihre Segmente möglich war. Es fehlte vor allem in kleineren Systemen an Messwerten für die Transportmengen in Abhängigkeit der Witterung zur Beurteilung des Transportverhaltens der Einzelsegmente. Erst diese Messwerte ermöglichen eine mathematische Modellbildung mit Parametrierung und damit Ansätze für eine Optimierung. In diesem Beitrag wird der Prototyp eines neuartigen Sensors vorgestellt, der die gleichzeitige, kostengünstige und zeitbegrenzte Erfassung der Abwasserströme an verschiedenen Punkten im Kanalnetz ermöglichen soll. Die im Abwasserstrom befindlichen Teile des Sensors sind preiswerte mechanische Komponenten, die kostengünstig und einfach zu ersetzen sind. Die Erfassung der Strömungsgeschwindigkeit und d...
2023 International Workshop on Impedance Spectroscopy (IWIS)
This paper presents an inductive measuring system using a two-pancake coil setup for monitoring t... more This paper presents an inductive measuring system using a two-pancake coil setup for monitoring the electromagnetic properties of steel sheets. An experimental setup was developed to perform measurements on cooling sheet metal samples during real structural transformations. Additional to the experiments with hot steel sheets, a simulation in COMSOL Multiphysics was used to validate the measurement results. The experiments conducted with the cooling material confirmed the suitability of the measurement system for the application described. The results obtained in this work show that by evaluating the phase shift between the exciting magnetic field H and the induction B, the structural transformation can be reliably monitored. In this work, a phase shift of 2 degrees was measured when a steel sheet was cooled by about 200 degrees Celsius.
ABSTRACT The bipolar transurethral resection is a further development of monopolar transurethral ... more ABSTRACT The bipolar transurethral resection is a further development of monopolar transurethral resection, being the gold standard in surgical treatment of prostate and bladder diseases. To create the metrological basis for understanding of electrical and physical processes during bipolar transurethral resection an experimental set-up to visualize spatial potential distribution around bipolar devices was developed. A hardware based signal conditioning and specific undersampling are presented as data acquisition methods for a sampling rate up to 1 MS/s. These methods are compared with the possibilities of a high speed data acquisition card. For more than four measuring channels and depending on the output bandwidth of the electrosurgical generator either hardware based signal conditioning or specific undersampling is suggested.
ABSTRACT In the field of magnetic inductance tomography,signal processing is a real challenge. Th... more ABSTRACT In the field of magnetic inductance tomography,signal processing is a real challenge. This is due to the divergent nature of magnetic fields. The sensitivity, i.e. the change in the receiving signal by means of an electrically conductive sample in a measuring volume depends strongly on the positioning of the sample. Objects that are located near the transmitting or receiving coils are very well locatable, where objects in larger distance are hard to detect. In this paper an approach is presented that improves the topology of the magnetic fields in the ”magnetic induction tomography” (MIT) by changing geometric constructions and current patterns of coils so far, as to allow a sharper localization of objects within the space. The aim is to level the distribution of the sensitivity in the measuring volume, so that electrically conductive objects with a larger distance between transmitting and receiving unit can be detected with almost the same signal intensity as objects close to the transmitting and receiving unit. The simulation tool Comsol is used for the geometric modeling making a finite element analysis (FEA). The subsequent signal processing and analysis of the simulation results are implemented in Matlab. Within this FEA the coil geometries and current patterns are changed numerically, so that the minimum object size, that is still detectable, is, compared to the known MIT, reduced and the sensitivity of the system is improved. To validate the simulation in Comsol c , first simulation results are compared with analytical models and analyses.
2009 6th International Multi-Conference on Systems, Signals and Devices, 2009
ABSTRACT Fat content of liver is an essential parameter to decide whether a liver is suitable for... more ABSTRACT Fat content of liver is an essential parameter to decide whether a liver is suitable for transplantation or not. The determination of fat content is often challenging and usually there is not enough time to bring a specimen to a pathologic laboratory. That is why transplantation clinics need a technique to measure the fat content of a graft. In this paper the theoretical basics and an existing laboratory setup are presented.
IEEE Transactions on Instrumentation and Measurement, 2014
ABSTRACT To analyze the electric field around bipolar resectoscopes, used in urology, in terms of... more ABSTRACT To analyze the electric field around bipolar resectoscopes, used in urology, in terms of reasons for late complications after a surgical treatment a flexible multielectrode system was developed to measure the 3-D potential distribution. A high spatial resolution is achieved with the least possible individual measurements under the conditions of a quasi-static electric field. A flexible arrangement and positioning of the measuring points in the vertical direction of the experimental environment enable an adjustable spatial resolution and the selection of the region of interest. The existing influence of the multielectrode system on the measuring results is described and a correction method is presented to achieve significant results. Thus, the multielectrode system is usable for a comparative study of bipolar resectoscopes varying in the arrangement of resection and return electrode.
ABSTRACT Bipolar electrosurgical systems are used for the treatment of benign prostatic hyperplas... more ABSTRACT Bipolar electrosurgical systems are used for the treatment of benign prostatic hyperplasia (BPH) in urology. In order to analyse electrothermal processes during surgery the power loss density distribution around a bipolar resectoscope is calculated out of the measured potential distribution in isotonic saline solution ex situ. During further analysis power loss density values act as input for the Penne's bioheat equation. To achieve results, which are as realistic as possible, a method to obtain power loss density values, depending on the observed tissue or medium in the operating field, is presented. Applying this method, the power loss density distribution in isotonic saline solution at 25 °C is compared to the distribution calculated for the average conductivity of biological tissue in the region of interest.
Die steigenden Anforderungen an den Umweltschutz bei möglichst niedrigen Kosten betreffen auch di... more Die steigenden Anforderungen an den Umweltschutz bei möglichst niedrigen Kosten betreffen auch die öffentlichen Kanalnetze und Kläranlagen. Speziell die Kanalnetze sind über Jahrzehnte gewachsen, ohne dass kostengünstig eine genaue Bilanz ihrer Leistungsfähigkeit bis in ihre Segmente möglich war. Es fehlte vor allem in kleineren Systemen an Messwerten für die Transportmengen in Abhängigkeit der Witterung zur Beurteilung des Transportverhaltens der Einzelsegmente. Erst diese Messwerte ermöglichen eine mathematische Modellbildung mit Parametrierung und damit Ansätze für eine Optimierung. In diesem Beitrag wird der Prototyp eines neuartigen Sensors vorgestellt, der die gleichzeitige, kostengünstige und zeitbegrenzte Erfassung der Abwasserströme an verschiedenen Punkten im Kanalnetz ermöglichen soll. Die im Abwasserstrom befindlichen Teile des Sensors sind preiswerte mechanische Komponenten, die kostengünstig und einfach zu ersetzen sind. Die Erfassung der Strömungsgeschwindigkeit und d...
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