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Methods of Technical Diagnostics
Klusáček, Stanislav ; Ďaďo, Stanislav (referee) ; Němec, Zdeněk (referee) ; Tůma, Jiří (referee) ; Bejček, Ludvík (advisor)
The main objective of the presented thesis is to contribute to the development of diagnostic methods for piezoelectric sensor testing. The thesis describes the methods for piezoelectric sensors microcracks identification and diagnostics. The core of the thesis presents the development of a knock sensor prototype, design of suitable methods for the knock sensors diagnosis and evaluation of developed methods with focus on detection of microcracks in the sensor piezoceramic. The last part of the thesis deals with the influence of cracks and splits on the measured data from the piezoelectric transducer. The presented methods are focusing on impedance measurements and sensors frequency response measurements. Known properties of used piezoelectric material as an information source for measurement and diagnosis are provided. The main result of the work is the evaluation of the methods developed for the piezoelectric sensors self-diagnosis.
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Control Software for RLC meter HIOKI 3532
Slovák, Martin ; Beneš, Petr (referee) ; Keprt, Jiří (advisor)
Aim of work gets up on questions and methods about measuring by RLC meter and realize control software for RLC meter HIOKI 3532. Theoretic part of work put mind to problems about impedance measuring, especially about means of their measuring. Next part deal with RLC meter HIOKI 3532 in particular to his properties, possibility of configuration and his communication by means of GPIB. Therefore next section surveys on the measuring systems, in accordance with standard GPIB. The main section is survey to control software for RLC meter HIOKI 3532 which is realize in the graphic programming language LabVIEW. The software made as an instrument to control and configuration of RLC meter parameters, which is needed to frequency response characteristic measuring and archiving. Work notes basic adumbration about software realization. And instruction for taking frequency response characteristic of measured item. Last part of the work contains from validation measure which took by the software.
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Impedance measurement with uncertainty assessment
Fiala, Radim ; Zavřel, Jiří (referee) ; Havlíková, Marie (advisor)
This Master’s thesis deals with standard uncertainity determination for electrical quantities measurement. Next, there are proposals of uncertainity calculation procedures for impedance measurement. Impedance is measured by LCR meter Agilent 4263B. Using the proposed procedures, standard uncertainities are then calculated. Furthermore, there is proposal for an improved laboratory exercise for the MEMT subject, implementing the standard measurement uncertainities calculations.
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IMPEDANCE MEASUREMENT OF GAS SENSORS WITH NICKEL(II)-AND COPPER(II)-OXIDE ACTIVE LAYERS
Horák, Pavel ; Khun, J. ; Vrňata, M. ; Bejšovec, Václav ; Lavrentiev, Vasyl ; Vacík, Jiří
Thin layers (90 nm) of nickel(II)- and copper(II)- oxide were deposited onto ceramic sensor substrates equipped with interdigital electrodes for signal reading. The deposition was carried out in two or three steps: (i) sputtering by means of Ar ion beam from pure (99.99%) metal targets, (ii) following thermal oxidation (400 degrees C for 5 h) in air, (iii) in some cases - sputtering of Pd catalyst to the surface. Then the impedance response of produced sensors (NiO, NiO+Pd, CuO, CuO+Pd) to 1000 ppm of hydrogen and 1000 ppm of methanol vapor was measured. Impedance measurements were performed in the frequency range from 40 Hz to 100 MHz. The obtained data were depicted in Nyquist representation (i.e. imaginary vs. real part of complex impedance). These diagrams have a character of one complete and one incomplete semicircle, each of them corresponding to a parallel RC-element. It was proved, that both NiO and CuO behave like p-type semiconductors; the sensor impedance increases on exposure to reducing gases. The best sensitivity was achieved on NiO+Pd sensor - during detection of hydrogen (1000 ppm) the real part of complex impedance measured at 40 Hz increased from 120 to 350 Omega.
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