Luca Bifano received the M.Sc. degree from the University of Bayreuth, Bayreuth, Germany, in 2018. Since 2018 he is with the Chair of Measurement and Control Systems, University of Bayreuth, Bayreuth, Germany. His current research interests include impedance measurement systems and their applications in field of bulk materials with the focus on foundry industry.
Dipl.-Ing. (univ.) Alice Fischerauer works since 2004 as a senior research and teaching associate with the Chair of Measurement and Control Systems at the University of Bayreuth. Her main research interests are on impedance spectroscopy and electrical capacitance tomography with focus on modelling and signal processing.
Gerhard Fischerauer (M’87) received the Dipl.-Ing. and Dr.-Ing. degrees from the Technical University of Munich, Munich, Germany, in 1989 and 1996, respectively. From 1990 to 2001, he was with the Microacoustics Group, Siemens Corporate Technology and Epcos, Munich, and then joined Siemens Matsushita, Munich. Since 2001, he has been the Chair of Measurement and Control Systems, University of Bayreuth, Bayreuth, Germany. His current research interests include metrology in general and sensor systems, microsensors, microwave engineering, and microacoustic device.
This paper discusses impedance spectroscopy as a method to characterize different types of quartz sand, chromite sand, and mixtures of sand. Based on two types of measurement cells, the impedance spectra for various dry sands were measured. The spectra differ enough to allow the sands to be distinguished. The results were validated by extracting the relative permittivity from the impedance and comparing it to literature data. After that, the method could be applied with confidence to other material systems. The influence of moisture was investigated with two types of quartz sand, and typical mixtures of form sand, chromite sand, and regenerated (quartz) sand were studied. In each case, the sand composition had a distinct influence on the Nyquist plot of the impedance spectrum. Compared to results from a laboratory foundry system, the new method exhibits a much more systematic dependence on the sand composition. If one succeeds in describing the impedance spectra with an equivalent circuit model parameterized by only a few parameters, these parameters could be used to identify and classify sand mixtures in the field. This would allow one, for example, to implement feedback control strategies in foundry regeneration processes, which would stabilize the processes and improve the quality of the casting products.
T. A. Belyaeva et al., “The effect of very low water content on the complex dielectric permittivity of clays, sand-clay and sand rocks,” Meas. Sci. Technol., Vol. 28, 2017. DOI: 10.1088/1361-6501/28/1/014005.)| false
H. Gemming, Prozesssicherheit in der Formstoffaufbereitung mit Hilfe der Fuzzy-Logik (in German), Ph.D. dissertation, Freiberg, 2003.
J. Winterhalter et al., “Vermeidung von Abfällen durch abfallarme Produktionsverfahren – Gießereialtsand aus Eisen-, Stahl- und Tempergießereien“ (in German). Karlsruhe, Dec. 1992.
C. H. Hamann and W. Vielstich, Elektrochemie (in German). Weilheim: Wiley-VCH, 2005.
W. Tilich, H. Polzin and M. Franke, Praxishandbuch bentonitgebundener Formstoff (in German). Berlin: Schiele & Schön, 2019.
F. Kremer and A. Schönhals, Broadband Dielectric Spectroscopy. New York: Springer, 2003.
VDG-Merkblatt R93, “Regenerierte Sande als Formgrundstoff-Anforderungen, Beurteilungskriterien“ (in German), Feb. 1992.
R. Harrington, Time-Harmonic Electromagnetic Fields. New York: IEEE Press, Wiley-Interscience, 2001.
J. Bartels, P. TenBruggencate, H. Hausen, K. H. Hellwege, K. L. Schäfer, E. Schmidt (eds.), Landolt-Börnstein: Zahlenwerte und Funktionen aus Physik, Chemie, Astronomie, Geophysik, Technik (in German). Vol. 2: Eigenschaften der Materie in ihren Aggregatszuständen. Part 6: K. H. Hellwege, A. M. Hellwege, Elektrische Eigenschaften I. Berlin: Springer, 1959, pp. 449–558.
S. Kirkpatrick, “Percolation and Conduction,” Rev. Modern Phys., Vol. 45, No. 4, pp. 574–588, 1973. DOI: .
TM – Technical Measurement is a professional journal for application-based industrial measurement technology, a key component of systems for automation, process monitoring, quality control, and security. It's the official organ of the AMA (Association for Sensor Technology) and the NAMUR (Process-Industry Interest Group for Automation Technology). It also includes notifications from the GMA (VDI/VDE-Society for Measurement and Automatic Control).