@inproceedings{BerndtLindnerTschurtschenthaleretal., author = {Berndt, Dominik and Lindner, Matthias and Tschurtschenthaler, Karl and Langer, Christoph and Schreiner, Rupert}, title = {Miniaturized Plasma Actuator Flow Measurements by MEMS-Based Thermal Conductivity Sensors}, series = {MDPI Proceedings of Eurosensors 2018, 9-12 September, Graz}, volume = {Vol.13}, booktitle = {MDPI Proceedings of Eurosensors 2018, 9-12 September, Graz}, number = {2}, doi = {10.3390/proceedings2130939}, abstract = {The gasflow created by a minaturized dielectric barrier discharge (DBD) plasma actuator is measured by a MEMS-based thermal conductivity gas sensor giving an indication of flow velocity and flow direction. The possiblity of several sensors in a small area gives a far better accuracy of local flow phenomena compared to conventional sensors. This is important for a better understanding of plasma- induced flow characteristics.}, language = {en} } @inproceedings{SteindlMottokMeieretal., author = {Steindl, Michael and Mottok, J{\"u}rgen and Meier, Hans and Schiller, Frank and Fr{\"u}chtl, M.}, title = {Safeguarded Processing of Sensor Data}, series = {IT-SecurityArea (IT-SA 2009) vom 13.-15. Oktober 2009, N{\"u}rnberg}, booktitle = {IT-SecurityArea (IT-SA 2009) vom 13.-15. Oktober 2009, N{\"u}rnberg}, pages = {8}, abstract = {The spectrum of software tasks no longer includes only rare function controlling tasks for sensor actuator chains in reactive embedded systems. However, more and more responsible challenges like safety-critical scenarios are tackled. Therefore sensor data have to be safeguarded by several mechanism. An obvious and widely used approach is the use of two redundant hardware controllers, but this comes along with an additional cost, space and energy factor. Another way to fulfill certain safety properties is to implement a second diverse software channel in a single micro-controller architecture according the Safely Embedded Software (SES) approach. However, a lack of performance occurs by implementing this diverse channel for complex computations e.g. floating-point operations. This paper gives an approach for transferring the SES into a coprocessor and to migrate SES to a flexible and powerful FPGA architecture.}, language = {en} } @inproceedings{SteindlMottokMeieretal., author = {Steindl, Michael and Mottok, J{\"u}rgen and Meier, Hans and Schiller, Frank and Fr{\"u}chtl, M.}, title = {Safeguarded Processing of Sensor Data}, series = {5th Embedded Real Time Software and Systems Conference (ERTS2 2010), May 2010, Toulouse, France}, booktitle = {5th Embedded Real Time Software and Systems Conference (ERTS2 2010), May 2010, Toulouse, France}, language = {en} } @inproceedings{EdlerHanschPrommesbergeretal., author = {Edler, Simon and Hansch, Walter and Prommesberger, Christian and Schreiner, Rupert}, title = {Influence of adsorbates on the performance of a field emitter array in a high voltage triode setup}, series = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, booktitle = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, publisher = {IEEE}, doi = {10.1109/IVNC.2018.8520214}, pages = {1-2}, abstract = {The influence of residual gas pressure on the characteristics of black-Silicon field emitter arrays in a high voltage triode setup is investigated. I-Vcharacteristics at different pressure levels show a decrease of emission current with rising pressure. This can be explained by an increase of the work function and charging of the emitter surface due to adsorbates. The initial characteristics can be restored by heating the FEA up to 110 °C during electron emission. This regeneration procedure enables an extension of the lifetime from about 20 h to 440 h at a residual gas pressure of 10 -5 mbar.}, language = {en} } @inproceedings{KaesbauerSchmailzlPrehmetal., author = {K{\"a}sbauer, Johannes and Schmailzl, Anton and Prehm, Jens and Loose, Tobias and Hierl, Stefan}, title = {Simulation of Quasi-Simultaneous Laser Transmission Welding of Plastics}, series = {Procedia CIRP}, volume = {94}, booktitle = {Procedia CIRP}, publisher = {Elsevier}, doi = {10.1016/j.procir.2020.09.136}, pages = {737 -- 741}, abstract = {Thermo-mechanical simulation offers great opportunities to optimize welding processes of plastics. For realistic simulation, the temperature dependent mechanical properties need to be implemented from ambient temperature to temperatures above the flow temperature. Standard test methods are insufficient for characterization in the entire temperature range because close to the flow temperature the material is too soft for tensile tests and too stiff for rheometry. Therefore, an optimization strategy is developed, that determines unknown material parameters by testing in welding simulations. The unknown parameters are iteratively adjusted to minimize the mismatch between computed and measured set-paths. Thus, important process characteristics are calculated realistically, enabling the computer aided assessment of the weld quality.}, subject = {Kunststoffschweißen}, language = {en} } @article{WeiglFeldmeierBierletal., author = {Weigl, Stefan and Feldmeier, Florian and Bierl, Rudolf and Matysik, Frank-Michael}, title = {Photoacoustic detection of acetone in N2 and synthetic air using a high power UV LED}, series = {Sensors Actuators B Chemical}, volume = {316}, journal = {Sensors Actuators B Chemical}, number = {August}, publisher = {Elsevier}, doi = {10.1016/j.snb.2020.128109}, pages = {1 -- 11}, abstract = {The performance of a photoacoustic trace gas sensor for the detection of acetone in N2 and synthetic air is reported. The sensor system utilises an amplitude modulated UV LED. The light source has an emission maximum at 278 nm and a maximum CW output power of 300 mW according to the datasheet. Three different collimating and focusing approaches have been investigated to guide the highly divergent LED light into the acoustic resonator of the photoacoustic measurement cell. A 3D printed aluminium cell was designed to optimize light coupling by simultaneously minimizing the photoacoustic background signal generation. Hence, the diameter of the resonator was set to a comparable large diameter of 10 mm and the inner walls of the resonator were mirror polished. The additive manufacturing procedure allowed for integration of a spirally formed gas channel, enabling gas heating prior to detection. The sensor performance was investigated by measuring acetone in N2 and synthetic air at different concentrations. The UV LED current was set to 86 \% of the maximum value according to the datasheet of the light source in order to increase the lifetime and thermal stability. An Allan-Werle deviation analysis validates a stable sensor performance. The limit of detection (LoD) was determined at a 3σ noise level with a 10 s lock-in amplifier time constant by sampling data points over 20 s with a data acquisition rate of 5 Hz. LoDs of 80.8 ppbV and 19.6 ppbV were obtained for acetone in N2 and synthetic air, respectively.}, language = {en} } @article{BerndtMuggliWittweretal., author = {Berndt, Dominik and Muggli, Josef and Wittwer, Franz and Langer, Christoph and Heinrich, Stephan and Knittel, Thorsten and Schreiner, Rupert}, title = {MEMS-based thermal conductivity sensor for hydrogen gas detection in automotive applications}, series = {Sensors and Actuators A: Physical}, volume = {305}, journal = {Sensors and Actuators A: Physical}, number = {April}, publisher = {Elsevier}, doi = {10.1016/j.sna.2019.111670}, abstract = {Accurate detection of hydrogen gas in vehicle interiors is very important for the future of a fuel cell car. Since this type of gas is highly volatile and flammable, the measurement methods have to be very reliable and precise due to safety reasons. In this paper a thermal conductivity sensor for hydrogen gas detection is presented, exhibiting a lower detection limit of 2000 ppm hydrogen in laboratory air. The sensor element is realized by micro-fabrication techniques on silicon wafers. The heated filament is exposed by a selective wet etching process creating a micro-hotplate on a thin membrane. In order to minimize power consumption, the sensor is operated in pulsed mode. Hydrogen gas detection was carried out using a synthetic gas testbench. Measurements of hydrogen contents ranging from 0\% to 4\% with an increment of 0.5\% were successfully performed for ambient gas temperatures between -15°C and 84°C. Including humidity, high moisture contents have the greatest influence on thermal conductivity. This was predicted in theoretical investigations and confirmed in experiments. For evaluation, both the change in resistance ΔR as well as the time constant τ were taken as sensor output. For both quantities, the previously established theoretical relationship with thermal conductivity could be confirmed.}, language = {en} } @article{WeiglWittmannRuecketal., author = {Weigl, Stefan and Wittmann, Elisabeth and R{\"u}ck, Thomas and Bierl, Rudolf and Matysik, Frank-Michael}, title = {Effects of ambient parameters and cross-sensitivities from O2, CO2 and H2O on the photoacoustic detection of acetone in the UV region}, series = {Sensors Actuators B Chemical}, journal = {Sensors Actuators B Chemical}, number = {328}, publisher = {Elsevier}, issn = {0925-4005}, doi = {10.1016/j.snb.2020.129001}, abstract = {We present a sensitive UV LED photoacoustic setup for the detection of gaseous acetone and discuss its applicability towards breath analysis. We investigated the performance of the sensor for low acetone concentrations down to 0.1 parts per million (ppmV). The influences of temperature, flow, pressure, optical power and LED duty cycle on the measured signal have been examined. To gain a better understanding of the different effects on the photoacoustic signal, correlation analysis was applied and feature importance was determined using a large measured dataset. Furthermore, the cross-sensitivities towards O2, CO2 and H2O have been studied extensively. Finally, the sensor's performance to detect acetone between 0.1-1 ppmV within gas mixtures simulating breath exhale conditions has been investigated, too. With a limit of detection (LoD) of 12.5 parts per billion (ppbV) (3σ) measured under typical breath exhale gas mixture conditions, the sensor demonstrated a high potential for the application of acetone detection in human breath analysis.}, language = {en} } @inproceedings{SchubertSeignDaietal., author = {Schubert, Martin J. W. and Seign, Stefan and Dai, Q. and Hinterseer, Sebastian and Pielmeier, F. and Pietsch, Alexander and Seebauer, C. and Weiß, Josef and Yu, C. and Zenger, Stefan}, title = {Capacitive Sensor Technology for Soil Moisture Monitoring Networks}, series = {24th IEEE International Conference on Electronics, Circuits and Systems (ICECS), 5-8 Dec. 2017, Batumi, Georgia}, booktitle = {24th IEEE International Conference on Electronics, Circuits and Systems (ICECS), 5-8 Dec. 2017, Batumi, Georgia}, doi = {10.1109/ICECS.2017.8292018}, pages = {190 -- 193}, abstract = {A sensor technology for tracking soil-moisture in agricultural fields is presented. A linear measurement method was developed to satisfy the need for cheap sensors with wide range of capacitance change such as factor 30. A combined wired and wireless network transmits data to a server. Various battery aspects are compared with respect to use in agriculture.}, language = {en} } @inproceedings{Schubert, author = {Schubert, Martin J. W.}, title = {System Contemplations for Precision Irrigation in Agriculture}, series = {AIP Conference Proceedings}, volume = {1828}, booktitle = {AIP Conference Proceedings}, number = {1}, isbn = {9780735414969}, doi = {10.1063/1.4979393}, abstract = {This communication contemplates political, biological and technical aspects for efficient and profitable irrigation in sustainable agriculture. A standard for irrigation components is proposed. The need for many, and three-dimensionally distributed, soil measurement points is explained, thus enabling the control of humidity in selected layers of earth. Combined wireless and wired data transmission is proposed. Energy harvesting and storage together with mechanical sensor construction are discussed.}, language = {en} } @inproceedings{LeeSchubertHo, author = {Lee, Wai-Kong and Schubert, Martin J. W. and Ho, Stanley Jian-Qin}, title = {Multi-source energy harvesting and storage for floating wireless-sensor-network nodes}, series = {2016 IEEE Industrial Electronics and Applications Conference (IEACon 2016), 20.-22. Nov. 2016, Kota Kinabalu, Malaysia}, booktitle = {2016 IEEE Industrial Electronics and Applications Conference (IEACon 2016), 20.-22. Nov. 2016, Kota Kinabalu, Malaysia}, isbn = {9781509009268}, language = {en} } @misc{SchubertSeign, author = {Schubert, Martin J. W. and Seign, Stefan}, title = {Arrangement for Measuring Capacitance}, language = {en} } @article{Weber, author = {Weber, Karsten}, title = {Die Macht der Maschinenmoral}, series = {Schweizer Monat}, journal = {Schweizer Monat}, number = {1077 - Juni}, language = {de} } @article{GerhardsWeberBittneretal., author = {Gerhards, Helene and Weber, Karsten and Bittner, Uta and Fangerau, Heiner}, title = {Machine Learning Healthcare Applications (ML-HCAs) Are No Stand-Alone Systems but Part of an Ecosystem - A Broader Ethical and Health Technology Assessment Approach is Needed}, series = {The American Journal of Bioethics - AJOB}, volume = {20}, journal = {The American Journal of Bioethics - AJOB}, number = {11}, doi = {10.1080/15265161.2020.1820104}, pages = {46 -- 48}, language = {de} } @article{StadlerHofmannMotschmannetal., author = {Stadler, Dominik and Hofmann, Matthias J. and Motschmann, Hubert and Shamonin (Chamonine), Mikhail}, title = {Automotived system for measuring the surface dilational modulus of liquid-air interfaces}, series = {Measurement Science and Technology}, volume = {27}, journal = {Measurement Science and Technology}, number = {6}, publisher = {IOP Science}, doi = {10.1088/0957-0233/27/6/065301}, pages = {065301}, abstract = {The surface dilational modulus is a crucial parameter for describing the rheological properties of aqueous surfactant solutions. These properties are important for many technological processes. The present paper describes a fully automated instrument based on the oscillating bubble technique. It works in the frequency range from 1 Hz to 500 Hz, where surfactant exchange dynamics governs the relaxation process. The originality of instrument design is the consistent combination of modern measurement technologies with advanced imaging and signal processing algorithms. Key steps on the way to reliable and precise measurements are the excitation of harmonic oscillation of the bubble, phase sensitive evaluation of the pressure response, adjustment and maintenance of the bubble shape to half sphere geometry for compensation of thermal drifts, contour tracing of the bubbles video images, removal of noise and artefacts within the image for improving the reliability of the measurement, and, in particular, a complex trigger scheme for the measurement of the oscillation amplitude, which may vary with frequency as a result of resonances. The corresponding automation and programming tasks are described in detail. Various programming strategies, such as the use of MATLAB® software and native C++ code are discussed. An advance in the measurement technique is demonstrated by a fully automated measurement. The instrument has the potential to mature into a standard technique in the fields of colloid and interface chemistry and provides a significant extension of the frequency range to established competing techniques and state-of-the-art devices based on the same measurement principle.}, language = {en} } @inproceedings{SilberbauerLindnerSchreiner, author = {Silberbauer, Theodor and Lindner, Matthias and Schreiner, Rupert}, title = {Charakterisierung der dielektrischen Barrierenentladung von Mikroplasmaaktuatoren in Abh{\"a}ngigkeit der Substratdicke}, series = {Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung : Fachbeitr{\"a}ge 2. Symposium Elektronik und Systemintegration ESI 2020}, booktitle = {Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung : Fachbeitr{\"a}ge 2. Symposium Elektronik und Systemintegration ESI 2020}, address = {Landshut}, pages = {64 -- 72}, language = {de} } @article{KrysztofMieraUrbańskietal., author = {Krysztof, Michał and Miera, Paweł and Urbański, Paweł and Grzebyk, Tomasz and Hausladen, Matthias and Schreiner, Rupert}, title = {Integrated silicon electron source for high vacuum microelectromechanical system devices}, series = {Journal of Vacuum Science \& Technology B}, volume = {42}, journal = {Journal of Vacuum Science \& Technology B}, number = {2}, publisher = {AIP Publishing}, issn = {2166-2746}, doi = {10.1116/6.0003385}, abstract = {The article presents the process of developing a silicon electron source designed for high-vacuum microelectromechanical system (HV MEMS) devices, i.e., MEMS electron microscope and MEMS x-ray source. Technological constraints and issues of such an electron source are explained. The transition from emitters made of carbon nanotubes to emitters made of pure silicon is described. Overall, the final electron source consists of a silicon tip emitter and a silicon gate electrode integrated on the same glass substrate. The source generates an electron beam without any carbon nanotube coverage. It generates a high and stable electron current and works after the final bonding process of an HV MEMS device.}, language = {en} } @article{SchreinerNaegeleKoerbletal., author = {Schreiner, Rupert and Naegele, Peter and K{\"o}rbl, M. and Groning, A. and Gentner, Jean-Louis and Schweizer, Heinz C.}, title = {Monolithically integrated tunable laterally coupled distributed-feedback lasers}, series = {Photonics Technology Letters}, volume = {13}, journal = {Photonics Technology Letters}, number = {12}, publisher = {IEEE}, doi = {10.1109/68.969880}, pages = {1277 -- 1279}, abstract = {A new method for fabrication of tunable InGaAsP-InP single-mode lasers without epitaxial overgrowth is reported. These devices show the advantage of a considerably simplified fabrication process compared to conventional tunable laser types. The lasers comprise an active Bragg reflector integrated with an uncorrugated separately pumped gain region. By adjusting the current through the Bragg reflector, the wavelength can be tuned between 1590.8 and 1595.2 nm.}, language = {en} } @unpublished{PangerlSukulRuecketal., author = {Pangerl, Jonas and Sukul, Pritam and R{\"u}ck, Thomas and Fuchs, Patricia and Weigl, Stefan and Miekisch, Wolfram and Bierl, Rudolf and Matysik, Frank-Michael}, title = {An Inexpensive Uv-Led Photoacoustic Based Real-Time Sensor-System Detecting Exhaled Trace-Acetone}, publisher = {Elsevier}, doi = {10.2139/ssrn.4724198}, abstract = {In this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) - providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 6.4 ppbV and an NNEA of 1.1E-9 Wcm-1Hz-0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field.}, language = {en} } @inproceedings{BuchnerKaiserHausladenetal., author = {Buchner, Philipp and Kaiser, Alexander and Hausladen, Matthias and Bartl, Mathias and Bachmann, Michael and Schreiner, Rupert}, title = {Silicon Nanowire Field Emitters with Integrated Extraction Gates Using Benzocyclobutene as an Insulator}, series = {37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic}, booktitle = {37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic}, publisher = {IEEE}, doi = {10.1109/IVNC63480.2024.10652314}, pages = {1 -- 2}, abstract = {We are continuously improving the performance of our field emission electron sources. In this work a geometrically optimized design of electron sources with silicon nanowire field emitters on pillars was fabricated. This new design increased the packing density of the emitters by using a hexagonal arrangement of the pillars and a pillar spacing of 40 µm. Benzocyclobutene was used as the insulator material for an integrated (Cr/Ni) extraction gate. A modified fabrication process for the field emitters further improved reproducibility and reliability. An emission current of about 0.4 mA was measured for 30 minutes at an extraction voltage of 250 V and an anode voltage of 500 V. Electron transmission through the gate reached almost 100\%.}, language = {en} }