Matthias Kahr

Mr. Matthias Kahr

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Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 March 2022 in Sensors
Verified
Journal Article
Open access
PDF file
MKMatthias Kahr
Matthias Kahr
GKGabor Kovács
Gabor Kovács
Markus LoinigMarkus Loinig
Markus Loinig
HBHubert Brückl
Hubert Brückl
Rolling element bearing faults significantly contribute to overall machine failures, which demand different strategies for condition monitoring and failure detection. Recent advancements in machine learning even further expedite the quest to improve accuracy in fault detection for economic purposes by minimizing scheduled maintenance. Challenging tasks, such as the gathering of high quality data to explicitly train an algorithm, still persist and are limited in terms of the availability of historical data. In addition, failure data from measurements are typically valid only for the particular machinery components and their settings. In this study, 3D multi-body simulations of a roller bearing with different faults have been conducted to create a variety of synthetic training data for a deep learning convolutional neural network (CNN) and, hence, to address these challenges. The vibration data from the simulation are superimposed with noise collected from the measurement of a healthy bearing and are subsequently converted into a 2D image via wavelet transformation before being fed into the CNN for training. Measurements of damaged bearings are used to validate the algorithm’s performance.

21 June 2019 in Physical Review Letters
Verified
Journal Article
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AKAndreas Kainz
Andreas Kainz
FKFranz Keplinger
Franz Keplinger
WHWilfried Hortschitz
Wilfried Hortschitz
MKMatthias Kahr
Matthias Kahr
HSHarald Steiner
Harald Steiner
WBWolfgang Bartmann
Wolfgang Bartmann
Many upcoming experiments in antimatter research require low-energy antiproton beams. With a kinetic energy in the order of 100 keV, the standard magnetic components to control and focus the beams become less effective. Therefore, electrostatic components are being developed and installed in transfer lines and storage rings. However, there is no equipment available to precisely map and check the electric field generated by these elements. Instead, one has to trust in simulations and, therefore, depend on tight fabrication tolerances. Here we present, for the first time, a noninvasive way to experimentally probe the electrostatic field in a 3D volume with a microsensor. Using the example of an electrostatic quadrupole focusing component, we find excellent agreement between a simulated and real field. Furthermore, it is shown that the spatial resolution of the probe is limited by the electric field curvature which is almost zero for the quadrupole. With a sensor resolution of 61  V/m/Hz, the field deviation due to a noncompliance with the tolerances can be resolved. We anticipate that this compact and practical field strength probe will be relevant also for other scientific and technological disciplines such as atmospheric electricity or safeguarding near power infrastructure.

1 November 2014
Verified
Conference Paper
Closed access
WHWilfried Hortschitz
Wilfried Hortschitz
HSHarald Steiner
Harald Steiner
MSMichael Stifter
Michael Stifter
FKFranz Kohl
Franz Kohl
MKMatthias Kahr
Matthias Kahr
FKFranz Keplinger
Franz Keplinger
Inclination sensors are essential elements in many different fields of application such as navigation, metrology, geodetics, geoscience, as well as in the consumer market. In general, for high precision navigation. The sensor's resolution is one of the key parameters to improve the performance and to open up new areas of applications. The implementation of a miniaturized optical readout is one of the most promising ways to accomplish this goal. This paper discusses the principle of a novel inclination sensor along with obtained measurements of two prototypes with different mechanical parameters. The achieved sensitivity is 0.044 V/° resulting in an angular resolution of 0.0051°.

25 January 2019 in Sensors
Verified
Journal Article
Open access
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MKMatthias Kahr
Matthias Kahr
MSMichael Stifter
Michael Stifter
HSHarald Steiner
Harald Steiner
WHWilfried Hortschitz
Wilfried Hortschitz
GKGabor Kovács
Gabor Kovács
FKFranz Keplinger
Franz Keplinger
Accurate knowledge of the spatial magnetic field distribution is necessary when measuring field gradients. Therefore, a MEMS magnetic field gradiometer is reported, consisting of two identical, but independent laterally oscillating masses on a single chip. The sensor is actuated by Lorentz force and read out by modulation of the light flux passing through stationary and moving arrays of the chip. This optical readout decouples the transducer from the electronic components. Both phase and intensity are recorded which reveals information about the uniformity of the magnetic field. The magnetic flux density is measured simultaneously at two points in space and the field gradient is evaluated locally. The sensor was characterised at ambient pressure by performing frequency and magnitude response measurements with coil and various different permanent magnet arrangements, resulting in a responsivity of 35.67 V/T and detection limit of 3.07 µT/ Hz (@ 83 Hz ENBW). The sensor is compact, offers a large dynamic measurement range and can be of low-cost by using conventional MEMS batch fabrication technology.

23 November 2018 in Proceedings
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Conference Paper
Open access
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MKMatthias Kahr
Matthias Kahr
HSHarald Steiner
Harald Steiner
WHWilfried Hortschitz
Wilfried Hortschitz
MSMichael Stifter
Michael Stifter
AKAndreas Kainz
Andreas Kainz
FKFranz Keplinger
Franz Keplinger
This paper reports a novel 3D-printed MEMS resonant magnetometer with optical readout which features a mechanical conversion of a vertical oscillation into a horizontal one. This demonstrates the advantages of 3D-printing technology in terms of rapid prototyping, low costs and fast product development cycles. In addition, 3D-printing enables ‘true’ three-dimensional MEMS structures in contrast to the traditional MEMS technology which allows only two dimensional structures. The measurement approach comprises a hybrid implementation of an optical modulator, an LED and a photodetector.

23 November 2018 in Proceedings
Verified
Conference Paper
Open access
PDF file
MKMatthias Kahr
Matthias Kahr
MDMatthias Domke
Matthias Domke
HSHarald Steiner
Harald Steiner
WHWilfried Hortschitz
Wilfried Hortschitz
MSMichael Stifter
Michael Stifter
This paper reports on a novel, miniaturized magnetomechanical transducer/sensor made of borosilicate glass with wide dynamic range. The prototype is manufactured with laser micromachining and ablation techniques. Compared to state of the art, borosilicate glass substrate offers the highest thermal shock resistance and is best suited for MEMS magnetometers, for aerospace and space applications or magnetic monitoring systems for diagnostics and plasma stability control of nuclear fusion experiments, where thermal shock resistance is a critical requirement.