Articles | Volume 12, issue 1
https://doi.org/10.5194/jsss-12-61-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/jsss-12-61-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular research article
| 
02 Feb 2023
Regular research article |
| 02 Feb 2023
| 02 Feb 2023
Real-time active-gas imaging of small gas leaks
Max Bergau
CORRESPONDING AUTHOR
Sensors Automation Lab, Endress+Hauser Process Solutions (DE) GmbH, 79110 Freiburg, Germany
Laboratory for Gas Sensors, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
Thomas Strahl
Department of Gas and Process Technology, Fraunhofer IPM, 79110 Freiburg, Germany
Laboratory for Gas Sensors, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
Benjamin Scherer
Sensors Automation Lab, Endress+Hauser Process Solutions (DE) GmbH, 79110 Freiburg, Germany
Jürgen Wöllenstein
Department of Gas and Process Technology, Fraunhofer IPM, 79110 Freiburg, Germany
Laboratory for Gas Sensors, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
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Armin Lambrecht, Carsten Bolwien, Hendrik Fuhr, Gerd Sulz, Annett Isserstedt-Trinke, André Magi, Steffen Biermann, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 12, 123–131, https://doi.org/10.5194/jsss-12-123-2023, https://doi.org/10.5194/jsss-12-123-2023, 2023
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Infrared spectroscopy is great for determining the composition of liquids. Combined with attenuated total reflection (ATR), one can just put the sample on the sensitive surface. We made a compact device with a diamond-coated silicon ATR crystal to protect the surface against aggressive fluids. Silicon crystal, light source and detector are hermetically sealed in a housing. Our tests show that the diamond coating enhanced the sensitivity compared to uncoated ATR elements as predicted by theory.
Katrin Schmitt, Mara Sendelbach, Christian Weber, Jürgen Wöllenstein, and Thomas Strahl
J. Sens. Sens. Syst., 12, 37–44, https://doi.org/10.5194/jsss-12-37-2023, https://doi.org/10.5194/jsss-12-37-2023, 2023
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We present a photoacoustic sensor enabling fast, inexpensive, and highly sensitive methane detection in environmental monitoring applications. Six different T-cell designs were both theoretically and experimentally investigated. The aim was to understand the photoacoustic signal generation and resonances in relation to the different cell geometries, and determine the long-term stability and the detection limits for methane. These were below the methane background concentration in air of 1.8 ppm.
Benedikt Bierer, Dario Grgić, Olena Yurchenko, Laura Engel, Hans-Fridtjof Pernau, Martin Jägle, Leonhard Reindl, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 10, 185–191, https://doi.org/10.5194/jsss-10-185-2021, https://doi.org/10.5194/jsss-10-185-2021, 2021
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Detection of flammable gases is necessary to avoid explosive atmospheres. Commercial pellistors require an operation temperature above 450 °C for the detection of methane. We present a novel wireless low-power catalytic gas sensor system based on non-precious metal catalyst for the detection of methane and propane operated at 350 °C. The combination of a MEMS-based sensor with a low-power radio system provides the opportunity to monitor complex infrastructures without using a power grid.
Olena Yurchenko, Hans-Fridtjof Pernau, Laura Engel, Benedikt Bierer, Martin Jägle, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 10, 37–42, https://doi.org/10.5194/jsss-10-37-2021, https://doi.org/10.5194/jsss-10-37-2021, 2021
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Differential thermal analysis (DTA) was used to examine the effect of the particle size and morphology of Co3O4 on its thermal response under exposure to 1 % CH4. The DTA response results from the catalytic oxidation of methane. Co3O4 samples differing in particle size and morphology were produced by ball milling or were synthesized. The investigations performed with temperatures between 250 and 450 °C reveal that both particle size and shape have a considerable effect on thermal response.
Thomas Strahl, Johannes Herbst, Eric Maier, Sven Rademacher, Christian Weber, Hans-Fridtjof Pernau, Armin Lambrecht, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 10, 25–35, https://doi.org/10.5194/jsss-10-25-2021, https://doi.org/10.5194/jsss-10-25-2021, 2021
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For safety, environmental and economic reasons, methane leak detection is one of the most requested tasks for gas measurement devices. This paper compares the performance of a laser-based optical and acoustical detection scheme at different wavelengths and laser types, respectively. This forms a good basis for further developments of methane leak detection devices or can help to choose the right configuration for a certain methane leak detection application.
Ralf E. Bernhardsgrütter, Christoph J. Hepp, Martin Jägle, Hans-Fridtjof Pernau, Katrin Schmitt, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 10, 5–12, https://doi.org/10.5194/jsss-10-5-2021, https://doi.org/10.5194/jsss-10-5-2021, 2021
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The selective catalytic reduction, an after-treatment method using diesel exhaust fluid (AdBlue), is needed to reduce the emissions of diesel combustion processes. It is crucial to monitor the diesel exhaust fluid. This article presents a platinum thin-film sensor using the 3-omega method to characterize the diesel exhaust fluid. The information about the concentration of urea in water can be extracted. The results show that this sensor can determine the urea content to within 1 % by weight.
Mahmoud El-Safoury, Christian Weber, Olaf Kiesewetter, Yvonne Hespos, André Eberhardt, Katrin Schmitt, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 9, 89–97, https://doi.org/10.5194/jsss-9-89-2020, https://doi.org/10.5194/jsss-9-89-2020, 2020
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The refrigerant R134a is classified as a greenhouse gas and was banned from use (in vehicles) by the European Union in 2017 due to its contribution to global warming. The more expensive alternative refrigerant R1234yf is considered an environmentally less harmful alternative owing to its significantly lower global warming potential. Our newly developed gas detector can detect both refrigerants separately and, thus, help prevent the use of illegal gas mixtures that contain both refrigerants.
Louisa Scholz, Alvaro Ortiz Perez, Benedikt Bierer, Jürgen Wöllenstein, and Stefan Palzer
J. Sens. Sens. Syst., 7, 535–541, https://doi.org/10.5194/jsss-7-535-2018, https://doi.org/10.5194/jsss-7-535-2018, 2018
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The availability of datasets providing information on the spatial and temporal evolution of greenhouse gas concentrations is of high relevance for the development of reliable climate simulations. Here we present a novel, non-dispersive infrared absorption spectroscopy (NDIR) device that can possibly act as a central building block of a sensor node to provide high-quality data of carbon dioxide (CO2) concentrations under field conditions at a high measurement rate.
Jochen Huber, Katrin Schmitt, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 5, 293–299, https://doi.org/10.5194/jsss-5-293-2016, https://doi.org/10.5194/jsss-5-293-2016, 2016
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A simulation model to predict system behaviour of photoacoustic CO2 sensors is presented. The sensor output signal that depends on the CO2 concentration can be simulated if the boundary conditions of the system are known. A comparison of simulated values with experimental results is made. There is good accordance between simulation and experiments. Photoacoustic gas sensors offer great potential for miniaturized gas sensors. The simulation model is an effective tool for further developments.
Related subject area
Sensor principles and phenomena: Optical and infrared sensors
Investigation of the degree of cross-linking of polyethylene and thermosets using absolute optical spectroscopy and Raman microscopy
Compact silicon-based attenuated total reflection (ATR) sensor module for liquid analysis
Non-invasive blood sugar detection by cost-effective capacitance spectroscopy
Resonant photoacoustic cells for laser-based methane detection
Fabrication of integrated polysilicon waveguides for mid-infrared absorption sensing
Near-infrared LED system to recognize road surface conditions for autonomous vehicles
Characterization of specular freeform surfaces from reflected ray directions using experimental ray tracing
Iterative feature detection of a coded checkerboard target for the geometric calibration of infrared cameras
The size-of-source effect in thermography
Method for fast determination of the angle of ionizing radiation incidence from data measured by a Timepix3 detector
Comparison of laser-based photoacoustic and optical detection of methane
Metrological characterization and calibration of thermographic cameras for quantitative temperature measurement
Detection of plastics in water based on their fluorescence behavior
Analysis of photoelastic properties of monocrystalline silicon
Evaluation of optical fibre sensors in the electrical domain
Infrared-based sensor system for contactless monitoring of wetness and ice
Miniaturized photoacoustic detection of organofluorine-based refrigerants
Characterization, calibration and validation of an industrial emissometer
Measurement of the absolute spectral responsivity in the mid-infrared based on the cryogenic electrical substitution radiometer and an optimized thermopile detector
Quantitative measurement of combustion gases in harsh environments using NDIR spectroscopy
Validation of three-component wind lidar sensor for traceable highly resolved wind vector measurements
Comparison between different fiber coatings and adhesives on steel surfaces for distributed optical strain measurements based on Rayleigh backscattering
Crack luminescence as an innovative method for detection of fatigue damage
Temperature sensing in underground facilities by Raman optical frequency domain reflectometry using fiber-optic communication cables
Evaluation of the pH-sensitive swelling of a hydrogel by means of a plasmonic sensor substrate
Temperature reconstruction of infrared images with motion deblurring
TSA infrared measurements for stress distribution on car elements
Transmitted light pH optode for small sample volumes
Purity monitoring in medical gas supply lines with quantum cascade laser technology
Efficient thermal infrared emitter with high radiant power
Refractive index sensing of gases based on a one-dimensional photonic crystal nanocavity
Development of a portable active long-path differential optical absorption spectroscopy system for volcanic gas measurements
Thermal imaging as a modern form of pyrometry
Multi-channel IR sensor system for determination of oil degradation
Florian Bergmann, Norbert Halmen, Claudia Scalfi-Happ, Dominik Reitzle, Alwin Kienle, Linda Mittelberg, Benjamin Baudrit, Thomas Hochrein, and Martin Bastian
J. Sens. Sens. Syst., 12, 175–185, https://doi.org/10.5194/jsss-12-175-2023, https://doi.org/10.5194/jsss-12-175-2023, 2023
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In this work, the determination of the degree of cross-linking was investigated using absolute optical measurements with an integrating sphere and Raman spectroscopy. PE-Xc, on the basis of HDPE and UHMWPE and various thermosets, was examined. Laboratory methods (e.g. wet chemical analysis, DSC, and DEA) were used for comparison. A good correlation of the results of the optical methods with those of the laboratory methods could be shown and serves as a basis for further investigations.
Armin Lambrecht, Carsten Bolwien, Hendrik Fuhr, Gerd Sulz, Annett Isserstedt-Trinke, André Magi, Steffen Biermann, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 12, 123–131, https://doi.org/10.5194/jsss-12-123-2023, https://doi.org/10.5194/jsss-12-123-2023, 2023
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Infrared spectroscopy is great for determining the composition of liquids. Combined with attenuated total reflection (ATR), one can just put the sample on the sensitive surface. We made a compact device with a diamond-coated silicon ATR crystal to protect the surface against aggressive fluids. Silicon crystal, light source and detector are hermetically sealed in a housing. Our tests show that the diamond coating enhanced the sensitivity compared to uncoated ATR elements as predicted by theory.
Shazzad Rassel, Md Rejvi Kaysir, Abdulrahman Aloraynan, and Dayan Ban
J. Sens. Sens. Syst., 12, 21–36, https://doi.org/10.5194/jsss-12-21-2023, https://doi.org/10.5194/jsss-12-21-2023, 2023
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Diabetes Mellitus (DM) is one of the very common diseases with no viable cure. However, it can be controlled by regulating the daily sugar intake. Diabetic patients need to prick their fingers a few times a day for monitoring sugar levels. To find an alternative, researchers have been working for decades on the development of a true non-invasive technique. In this effort, we developed a cost-effective non-invasive technique for measuring blood sugar levels using capacitance spectroscopy.
Katrin Schmitt, Mara Sendelbach, Christian Weber, Jürgen Wöllenstein, and Thomas Strahl
J. Sens. Sens. Syst., 12, 37–44, https://doi.org/10.5194/jsss-12-37-2023, https://doi.org/10.5194/jsss-12-37-2023, 2023
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We present a photoacoustic sensor enabling fast, inexpensive, and highly sensitive methane detection in environmental monitoring applications. Six different T-cell designs were both theoretically and experimentally investigated. The aim was to understand the photoacoustic signal generation and resonances in relation to the different cell geometries, and determine the long-term stability and the detection limits for methane. These were below the methane background concentration in air of 1.8 ppm.
Gerald Stocker, Cristina Consani, Pooja Thakkar, Clement Fleury, Andreas Tortschanoff, Khaoula-Farah Ourak, Gerald Pühringer, Reyhaneh Jannesari, Parviz Saeidi, Elmar Aschauer, Ulf Bartl, Christoph Kovatsch, Thomas Grille, and Bernhard Jakoby
J. Sens. Sens. Syst., 11, 225–231, https://doi.org/10.5194/jsss-11-225-2022, https://doi.org/10.5194/jsss-11-225-2022, 2022
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We motivate how integrated waveguides (WGs) can be part of an on-chip non-dispersive infrared sensor system for environmental sensing. We report the hurdles in maintaining WG quality when integrating emitter and detector structures on the same chip. Thus, we introduce the concept of how to determine the intrinsic loss and a process scheme to protect WG structures from damage caused during fabrication. This could pave the way to systems for environmental sensing with a minimal footprint.
Hongyi Zhang, Shéhérazade Azouigui, Rabia Sehab, and Moussa Boukhnifer
J. Sens. Sens. Syst., 11, 187–199, https://doi.org/10.5194/jsss-11-187-2022, https://doi.org/10.5194/jsss-11-187-2022, 2022
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In this paper, a near-infrared LED system is proposed for autonomous vehicles to distinguish between weather-induced road surface conditions (dry, wet, snow, ice, water). For the LED spectra, the influence of the LED bandwidth is investigated. To assess the performance of the system for a long detection range, experiments with large incident angles are conducted. The feasibility of this system is proved via a laboratory experiment with three near-infrared LEDs and a camera.
Tobias Binkele, David Hilbig, Mahmoud Essameldin, Thomas Henning, Friedrich Fleischmann, and Walter Lang
J. Sens. Sens. Syst., 10, 261–270, https://doi.org/10.5194/jsss-10-261-2021, https://doi.org/10.5194/jsss-10-261-2021, 2021
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The development of optical design is characterized by the desire for more applications and better performance. The latest result of this development is freeform optics offering almost unlimited possibilities for the designers. However, an optical component has also to be manufactured and tested by metrology. We propose a measurement technique for the surface characterization of freeform optical components and highlight the possible error sources and their influence on the measurement result.
Sebastian Schramm, Jannik Ebert, Johannes Rangel, Robert Schmoll, and Andreas Kroll
J. Sens. Sens. Syst., 10, 207–218, https://doi.org/10.5194/jsss-10-207-2021, https://doi.org/10.5194/jsss-10-207-2021, 2021
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During the geometric calibration of infrared cameras, the parameters that describe where object points are mapped onto thermal images are determined. The required reference data is obtained by capturing so-called calibration targets. In established approaches, it is difficult to estimate the lens distortions precisely. A newly developed target and its evaluation algorithm make it possible to increase the sensitivity of the calibration by finding reference points close to image borders.
Helmut Budzier and Gerald Gerlach
J. Sens. Sens. Syst., 10, 179–184, https://doi.org/10.5194/jsss-10-179-2021, https://doi.org/10.5194/jsss-10-179-2021, 2021
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In thermometry, the displayed temperature value of an object depends on the size of the object. This behaviour, the size-of-source effect, might be a major cause of measurement uncertainty in a thermoscene. The influence of diffraction and digitization can be described advantageously with the modulation transfer function. Especially with very small objects the displayed temperatures are too low. When imaging large objects, not only the edge areas are affected, but also the entire image.
Felix Lehner, Jürgen Roth, Oliver Hupe, Marc Kassubeck, Benedikt Bergmann, Petr Mánek, and Marcus Magnor
J. Sens. Sens. Syst., 10, 63–70, https://doi.org/10.5194/jsss-10-63-2021, https://doi.org/10.5194/jsss-10-63-2021, 2021
Thomas Strahl, Johannes Herbst, Eric Maier, Sven Rademacher, Christian Weber, Hans-Fridtjof Pernau, Armin Lambrecht, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 10, 25–35, https://doi.org/10.5194/jsss-10-25-2021, https://doi.org/10.5194/jsss-10-25-2021, 2021
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For safety, environmental and economic reasons, methane leak detection is one of the most requested tasks for gas measurement devices. This paper compares the performance of a laser-based optical and acoustical detection scheme at different wavelengths and laser types, respectively. This forms a good basis for further developments of methane leak detection devices or can help to choose the right configuration for a certain methane leak detection application.
Sebastian König, Berndt Gutschwager, Richard Dieter Taubert, and Jörg Hollandt
J. Sens. Sens. Syst., 9, 425–442, https://doi.org/10.5194/jsss-9-425-2020, https://doi.org/10.5194/jsss-9-425-2020, 2020
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We present the metrological characterization and calibration of three different types of thermographic cameras for quantitative temperature measurement traceable to the International Temperature Scale (ITS-90). Relevant technical specifications are determined according to the requirements given in the series of Technical Directives VDI/VDE 5585. For the IETD and the NU, we also show how a significant improvement in the parameters can be achieved with the help of the data reference method.
Maximilian Wohlschläger and Martin Versen
J. Sens. Sens. Syst., 9, 337–343, https://doi.org/10.5194/jsss-9-337-2020, https://doi.org/10.5194/jsss-9-337-2020, 2020
Markus Stoehr, Gerald Gerlach, Thomas Härtling, and Stephan Schoenfelder
J. Sens. Sens. Syst., 9, 209–217, https://doi.org/10.5194/jsss-9-209-2020, https://doi.org/10.5194/jsss-9-209-2020, 2020
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Photoelasticity is considered a useful measurement tool for non-destructive and contactless determination of mechanical stresses or strains in the production of silicon wafers. In this work, a detailed derivation for the anisotropic stress-optic law is presented, and the corresponding stress-optical parameters are measured.
Ulrich Nordmeyer, Niels Neumann, Xiaozhou Wang, Dirk Plettemeier, Torsten Thiel, and Konstantin Kojucharow
J. Sens. Sens. Syst., 9, 199–208, https://doi.org/10.5194/jsss-9-199-2020, https://doi.org/10.5194/jsss-9-199-2020, 2020
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A completely new evaluation method for optical sensors is investigated in this paper. It originates from research that integrates optical sensors into radio-over-fibre networks. The laboratory-based experimental set-up is explained, and the findings are validated by a comparison to the conventional evaluation scheme. Finally, the work provides a detailed mathematical model to understand the implications of this new read-out method for practical applications.
Lakshan Tharmakularajah, Jakob Döring, and Karl-Ludwig Krieger
J. Sens. Sens. Syst., 9, 133–141, https://doi.org/10.5194/jsss-9-133-2020, https://doi.org/10.5194/jsss-9-133-2020, 2020
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In order to differentiate between a wet and a dry road surface, the water film height should be measured by using an infrared-based sensor system. By means of different wavelengths, it is also possible to distinguish between ice and water. In this article, a sensor system for the determination of the physical state of water on different surfaces using infrared LEDs and one photodiode is presented. This shall serve as a basis for the calculation of the road condition.
Mahmoud El-Safoury, Christian Weber, Olaf Kiesewetter, Yvonne Hespos, André Eberhardt, Katrin Schmitt, and Jürgen Wöllenstein
J. Sens. Sens. Syst., 9, 89–97, https://doi.org/10.5194/jsss-9-89-2020, https://doi.org/10.5194/jsss-9-89-2020, 2020
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The refrigerant R134a is classified as a greenhouse gas and was banned from use (in vehicles) by the European Union in 2017 due to its contribution to global warming. The more expensive alternative refrigerant R1234yf is considered an environmentally less harmful alternative owing to its significantly lower global warming potential. Our newly developed gas detector can detect both refrigerants separately and, thus, help prevent the use of illegal gas mixtures that contain both refrigerants.
Elena Kononogova, Albert Adibekyan, Christian Monte, and Jörg Hollandt
J. Sens. Sens. Syst., 8, 233–242, https://doi.org/10.5194/jsss-8-233-2019, https://doi.org/10.5194/jsss-8-233-2019, 2019
Tobias Pohl, Peter Meindl, Uwe Johannsen, Dieter Taubert, and Lutz Werner
J. Sens. Sens. Syst., 8, 195–205, https://doi.org/10.5194/jsss-8-195-2019, https://doi.org/10.5194/jsss-8-195-2019, 2019
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The Physikalisch-Technische Bundesanstalt (PTB) expanded its capabilities in the International System of Units (SI)-traceable absolute measurement of radiant power into the spectral range of the mid-infrared (MIR) by implementing additional MIR laser radiation sources at one of the PTB's cryogenic electrical substitution radiometer facilities. This extension enables absolute calibrations of the spectral responsivity of detectors in the MIR with low uncertainty.
Christian Niklas, Stephan Bauke, Fabian Müller, Kai Golibrzuch, Hainer Wackerbarth, and Georgios Ctistis
J. Sens. Sens. Syst., 8, 123–132, https://doi.org/10.5194/jsss-8-123-2019, https://doi.org/10.5194/jsss-8-123-2019, 2019
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We present in our paper two types of optical sensors that are capable of measuring the environmentally significant gases such as carbon oxide and dioxide as well as methane and water through absorption of light even in harsh environments of high temperature and pressure. Thus the sensors render it possible to measure inside combustion engines or in civilian fireplaces, which is necessary to meet the increasing demands of environmental protection regulations.
Stefan Oertel, Michael Eggert, Christian Gutsmuths, Paul Wilhelm, Harald Müller, and Helmut Többen
J. Sens. Sens. Syst., 8, 9–17, https://doi.org/10.5194/jsss-8-9-2019, https://doi.org/10.5194/jsss-8-9-2019, 2019
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Traceable wind velocity measurements with high resolution play a critical role in the field of wind energy. In this article we present a novel bistatic wind lidar system that has a high spatial and temporal resolution and a reduced measurement uncertainty compared to conventional systems as evidenced by comparison measurements. A first validation measurement in a wind tunnel with a laser Doppler anemometer as a flow velocity reference confirms the high accuracy of the bistatic lidar system.
Martin Weisbrich and Klaus Holschemacher
J. Sens. Sens. Syst., 7, 601–608, https://doi.org/10.5194/jsss-7-601-2018, https://doi.org/10.5194/jsss-7-601-2018, 2018
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The study describes how distributed optical strain measurement can be applied to steel surfaces. With the method presented, strain transfers from the substrate to the fiber core can be achieved that are almost identical to those of the reference measurement, especially with Ormocer® and polyimide coating.
The research results are to be used in the future for strain measurement in concrete construction on reinforcing steel.
Ruben Makris, Falk Hille, Marc Thiele, Dirk Kirschberger, and Damian Sowietzki
J. Sens. Sens. Syst., 7, 259–266, https://doi.org/10.5194/jsss-7-259-2018, https://doi.org/10.5194/jsss-7-259-2018, 2018
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In structural parts under vibrational loading fatigue cracks can initiate and grow, which can lead to structural failure. Conventional non-destructive testing methods for crack detection provide just a snapshot of fatigue crack evolution, whereas crack luminescence coating realizes clear visibility of the entire crack formation. Fatigue causing cyclic tensile tests and examinations on special test bodies allowing control of the crack opening width demonstrate a high sensitivity of the coating.
Markus Brüne, Wilhelm Furian, Wieland Hill, and Andreas Pflitsch
J. Sens. Sens. Syst., 7, 85–90, https://doi.org/10.5194/jsss-7-85-2018, https://doi.org/10.5194/jsss-7-85-2018, 2018
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The climate conditions in underground transportation facilities, especially the current airflow in terms of direction and speed, are the key factor driving smoke propagation in the case of a tunnel fire. Sensing this airflow is cost-intensive. Therefore, this paper focuses on gaining the information from temperature sensing along the tunnels using already installed optical fibers normally used for communications. This technique can replace thousands of temperature sensors.
Christoph Kroh, Roland Wuchrer, Margarita Günther, Thomas Härtling, and Gerald Gerlach
J. Sens. Sens. Syst., 7, 51–55, https://doi.org/10.5194/jsss-7-51-2018, https://doi.org/10.5194/jsss-7-51-2018, 2018
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The inline monitoring of parameters in aqueous liquids is facing an increasing demand in many application areas. In this paper we report on an optical monitoring of the pH value in liquids by means of a sensitive hydrogel, which can be applied in the physiological range. Our results indicate a nearly linear dependency between pH value and hydrogel swelling. Furthermore, we show an improvement of the response time by a factor of 2 in comparison to other systems exploiting this kind of hydrogel.
Beate Oswald-Tranta
J. Sens. Sens. Syst., 7, 13–20, https://doi.org/10.5194/jsss-7-13-2018, https://doi.org/10.5194/jsss-7-13-2018, 2018
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Images of an infrared camera show blurring effects while recording a moving object. Not only the contrast is corrupted by the motion but also the object temperature seems to be lower. It is shown how such images and the true temperature with a good approximation can be restored. Since the detection mechanism of an infrared camera is different from usual digital cameras, also the restoration is different. Examples are presented for motion deblurring used to restore images with different motions.
Roberto Marsili and Gianluca Rossi
J. Sens. Sens. Syst., 6, 361–365, https://doi.org/10.5194/jsss-6-361-2017, https://doi.org/10.5194/jsss-6-361-2017, 2017
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The car production industry is being subjected to more and more pressing technological challenges. In this framework the use of an advanced measurement technique such as thermoelasticity allows the engineers to have a fast and reliable tool for experimental investigation, optimization and validation of the FEM models. In this work it is shown how the thermoelastic measurement technique can be used to optimize a Ferrari car frame.
Christian Rogge, Steffen Zinn, Paolo Prosposito, Roberto Francini, and Andreas H. Foitzik
J. Sens. Sens. Syst., 6, 351–359, https://doi.org/10.5194/jsss-6-351-2017, https://doi.org/10.5194/jsss-6-351-2017, 2017
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This work presents a cost-effective optical-based sensor for pH monitoring of sample volumes less than 150 µL. As part of a bigger project to develop a stand-alone micro bioreactor system, measurements carried out with phenol red and DMEM reported a standard error of calibration in the physiologic pH range (6.5–7.5) of pH ±0.04. Compared to other accessible optical-based sensors this reported system is a good alternative regarding the overall costs of less than EUR 50.
Henrik Zimmermann, Mathias Wiese, Luigi Fiorani, and Alessandro Ragnoni
J. Sens. Sens. Syst., 6, 155–161, https://doi.org/10.5194/jsss-6-155-2017, https://doi.org/10.5194/jsss-6-155-2017, 2017
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Because of their direct impact on patients, medical supply lines are under strict regulations and have to be monitored in terms of purity on a regular basis. State-of-the-art measurement solutions do not allow for continuous bedside monitoring. The aim of the presented work is to provide a compact multispecies monitoring system based on the latest quantum cascade laser technologies allowing for the continuous bedside monitoring of medical gases.
T. Ott, M. Schossig, V. Norkus, and G. Gerlach
J. Sens. Sens. Syst., 4, 313–319, https://doi.org/10.5194/jsss-4-313-2015, https://doi.org/10.5194/jsss-4-313-2015, 2015
M. Mohebbi
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Short summary
Imaging of greenhouse gases is of great interest due to global warming. A spectroscopic method, using an active illumination of the scene, is presented. It allows for imaging and concentration measurements of much smaller gas plumes and leaks than current state-of-the-art gas cameras (optical gas imaging cameras). A real-time camera is realized and validated using known methane concentrations.
Imaging of greenhouse gases is of great interest due to global warming. A spectroscopic method,...
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