Pub Date : 2021-05-03DOI: 10.5194/JSSS-10-121-2021
O. Buryy, I. Syvorotka, Y. Suhak, U. Yakhnevych, D. Sugak, S. Ubizskii, H. Fritze
Abstract. The actuators for precise positioning based on bimorph structures of piezoelectric LiNbO 3 and LiTaO 3 crystals are considered. The optimal orientations of the actuator plates ensuring the highest possible displacements are determined by the extreme surfaces technique and the finite-element method. The simulated displacements for optimal orientations of LiNbO 3 and LiTaO 3 plates are compared with those obtained experimentally for manufactured LiNbO 3 and LiTaO 3 actuators, whose orientations are not optimal. As is shown, the optimal configuration of the actuator allows us to significantly increase its displacement for both LiNbO 3 and LiTaO 3 specimens.
{"title":"Determination of optimal crystallographic orientations for LiNbO3 and LiTaO3 bimorph actuators","authors":"O. Buryy, I. Syvorotka, Y. Suhak, U. Yakhnevych, D. Sugak, S. Ubizskii, H. Fritze","doi":"10.5194/JSSS-10-121-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-121-2021","url":null,"abstract":"Abstract. The actuators for precise positioning based on bimorph\u0000structures of piezoelectric LiNbO 3 and LiTaO 3 crystals are\u0000considered. The optimal orientations of the actuator plates ensuring the\u0000highest possible displacements are determined by the extreme surfaces\u0000technique and the finite-element method. The simulated displacements for optimal orientations of LiNbO 3 and LiTaO 3 plates are compared with\u0000those obtained experimentally for manufactured LiNbO 3 and LiTaO 3 actuators, whose orientations are not optimal. As is shown, the optimal configuration of the actuator allows us to significantly increase its displacement\u0000for both LiNbO 3 and LiTaO 3 specimens.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41593189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-23DOI: 10.5194/JSSS-10-109-2021
Tobias T. Pohl, P. Meindl, L. Werner, U. Johannsen, D. Taubert, C. Monte, J. Hollandt
Abstract. The Physikalisch-Technische Bundesanstalt (PTB) has set up an additional measurement approach for the absolute calibration of the spectral responsivity of detectors in the near-infrared (NIR) and mid-infrared (MIR) spectral range. This alternative method uses the radiation of a blackbody operating at about 1200 K with a precision aperture. The blackbody radiation can be calculated by Planck's law and is additionally spectrally selected by accurately characterized optical bandpass filters. Thus, a calibration of the spectral responsivity of a detector with respect to irradiance can be achieved at the bandpass wavelength of the applied transmission filters. If the aperture of the detector is known, the spectral responsivity can also be calculated with respect to radiant power. Thermopile detectors with known aperture size were calibrated in terms of their spectral responsivity with several bandpass filters in the spectral range between 1.5 µ m up to 14 µ m with relative standard measurement uncertainties between 5 % and 19 %. The obtained results are consistent with previous calibrations at PTB's national primary detector standard. Therefore, this additional measurement approach is a further validation of the existing primary method which is based on a cryogenic radiometer and extends the usable wavelength range.
{"title":"Absolute calibration of the spectral responsivity of thermal detectors in the near-infrared (NIR) and mid-infrared (MIR) regions by using blackbody radiation","authors":"Tobias T. Pohl, P. Meindl, L. Werner, U. Johannsen, D. Taubert, C. Monte, J. Hollandt","doi":"10.5194/JSSS-10-109-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-109-2021","url":null,"abstract":"Abstract. The Physikalisch-Technische Bundesanstalt (PTB) has set up an additional measurement approach for the absolute calibration of the spectral responsivity of detectors in the near-infrared (NIR) and mid-infrared (MIR) spectral range. This alternative method uses the radiation of a blackbody operating at about 1200 K with a precision aperture. The blackbody radiation can be calculated by Planck's law and is additionally spectrally selected by accurately characterized optical bandpass filters. Thus, a calibration of the spectral responsivity of a detector with respect to irradiance can be achieved at the bandpass wavelength of the applied transmission filters. If the aperture of the detector is known, the spectral responsivity can also be calculated with respect to radiant power. Thermopile detectors with known aperture size were calibrated in terms of\u0000their spectral responsivity with several bandpass filters in the spectral\u0000range between 1.5 µ m up to 14 µ m with relative standard\u0000measurement uncertainties between 5 % and 19 %. The obtained results\u0000are consistent with previous calibrations at PTB's national primary detector standard. Therefore, this additional measurement approach is a further validation of the existing primary method which is based on a cryogenic radiometer and extends the usable wavelength range.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45336097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-22DOI: 10.5194/JSSS-10-101-2021
M. Kaufmann, I. Effenberger, M. Huber
Virtual assembly (VA) is a method for datum definition and quality prediction of assemblies considering local form deviations of relevant geometries. Point clouds of measured objects are registered in order to recreate the objects’ hypothetical physical assembly state. By VA, the geometrical verification becomes more accurate and, thus, increasingly function oriented. The VA algorithm is a nonlinear, constrained derivate of the Gaussian best fit algorithm, where outlier points strongly influence the registration result. In order to assess the robustness of the developed algorithm, the propagation of measurement uncertainties through the nonlinear transformation due to VA is studied. The work compares selected propagation methods distinguished from their levels of abstraction. The results reveal larger propagated uncertainties by VA compared to the unconstrained Gaussian best fit. 1 Current trends in dimensional metrology and state-of-the-art datum definition and uncertainty assessment As quality demands on products increase, tolerance specifications for parts become more and more complex. With these challenging geometrical specifications, verification algorithms are required that represent the geometrical system more precisely. According to Nielsen (2003), in the last few decades, dimensional tolerances shrank due to improved manufacturing systems. However, the form deviations could not be reduced by the same extent. Therefore, their consideration should be intensified. A main deficit in the current International Organization for Standardization (ISO) standard for datum definition, ISO 5459 (Deutsches Institut für Normung e.V., 2011), is the lack of consideration of local form deviations for datum features. A datum feature is defined as a “real (non-ideal) integral feature used for establishing a single datum” (Deutsches Institut für Normung e.V., 2017, p. 2). Datum systems composed of three datum features mathematically define a coordinate system. This allows the definition of tolerance zones for extrinsic tolerances (Weißgerber and Keller, 2014). About 80 % of all measurement tasks require datum systems, so a further function-oriented datum system definition has a strong impact on geometrical verification. Hence, an assessment of the uncertainty for datum systems is of broad interest. Figure 1 shows a datum definition, where three perpendicular associated planes are considered in a nested approach. The primary datum constrains 3 degrees of freedom (DOF), the secondary datum 2 DOF and the tertiary datum 1 DOF (Gröger, 2015). 1.1 Concept of the virtual assembly In this paper, measurement data of physical objects are gathered from measurements using industrial computed tomography (CT). Registration is the action of aligning a data set relatively to another according to a datum definition in a common coordinate system. Virtual assembly (VA) comprises the consideration of local form deviations in the datum system computation. As shown in Fig. 1a, th
{"title":"Measurement uncertainty assessment for virtual assembly","authors":"M. Kaufmann, I. Effenberger, M. Huber","doi":"10.5194/JSSS-10-101-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-101-2021","url":null,"abstract":"Virtual assembly (VA) is a method for datum definition and quality prediction of assemblies considering local form deviations of relevant geometries. Point clouds of measured objects are registered in order to recreate the objects’ hypothetical physical assembly state. By VA, the geometrical verification becomes more accurate and, thus, increasingly function oriented. The VA algorithm is a nonlinear, constrained derivate of the Gaussian best fit algorithm, where outlier points strongly influence the registration result. In order to assess the robustness of the developed algorithm, the propagation of measurement uncertainties through the nonlinear transformation due to VA is studied. The work compares selected propagation methods distinguished from their levels of abstraction. The results reveal larger propagated uncertainties by VA compared to the unconstrained Gaussian best fit. 1 Current trends in dimensional metrology and state-of-the-art datum definition and uncertainty assessment As quality demands on products increase, tolerance specifications for parts become more and more complex. With these challenging geometrical specifications, verification algorithms are required that represent the geometrical system more precisely. According to Nielsen (2003), in the last few decades, dimensional tolerances shrank due to improved manufacturing systems. However, the form deviations could not be reduced by the same extent. Therefore, their consideration should be intensified. A main deficit in the current International Organization for Standardization (ISO) standard for datum definition, ISO 5459 (Deutsches Institut für Normung e.V., 2011), is the lack of consideration of local form deviations for datum features. A datum feature is defined as a “real (non-ideal) integral feature used for establishing a single datum” (Deutsches Institut für Normung e.V., 2017, p. 2). Datum systems composed of three datum features mathematically define a coordinate system. This allows the definition of tolerance zones for extrinsic tolerances (Weißgerber and Keller, 2014). About 80 % of all measurement tasks require datum systems, so a further function-oriented datum system definition has a strong impact on geometrical verification. Hence, an assessment of the uncertainty for datum systems is of broad interest. Figure 1 shows a datum definition, where three perpendicular associated planes are considered in a nested approach. The primary datum constrains 3 degrees of freedom (DOF), the secondary datum 2 DOF and the tertiary datum 1 DOF (Gröger, 2015). 1.1 Concept of the virtual assembly In this paper, measurement data of physical objects are gathered from measurements using industrial computed tomography (CT). Registration is the action of aligning a data set relatively to another according to a datum definition in a common coordinate system. Virtual assembly (VA) comprises the consideration of local form deviations in the datum system computation. As shown in Fig. 1a, th","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47001547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Porous poly(N -isopropylacrylamide) (PNIPAAm) hydrogels with pore diameters in the nanometer and the micrometer range were synthesized using two variations of the surfactant-based template method. We showed that smaller pore diameters lead to faster swelling and deswelling. A graphic representation of a model describing the swelling kinetics explains the assumption that the release and the uptake of water is faster for a larger specific surface area, that is smaller pore diameters. Additionally, the open-porous channel structure benefits the water transport compared to a nonporous PNIPAAm hydrogel. Sensor measurements result in response times between 36 s and 4 min also showing the importance of mechanical stability of porous hydrogels.
{"title":"Studies on porosity in poly(N-isopropylacrylamide) hydrogels for fast-responsive piezoresistive microsensors","authors":"D. Franke, G. Gerlach","doi":"10.5194/JSSS-10-93-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-93-2021","url":null,"abstract":"Porous poly(N -isopropylacrylamide) (PNIPAAm) hydrogels with pore diameters in the nanometer and the micrometer range were synthesized using two variations of the surfactant-based template method. We showed that smaller pore diameters lead to faster swelling and deswelling. A graphic representation of a model describing the swelling kinetics explains the assumption that the release and the uptake of water is faster for a larger specific surface area, that is smaller pore diameters. Additionally, the open-porous channel structure benefits the water transport compared to a nonporous PNIPAAm hydrogel. Sensor measurements result in response times between 36 s and 4 min also showing the importance of mechanical stability of porous hydrogels.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44630731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Ion-selective electrodes (ISEs) have been proven particularly useful in water analysis. They are usually used as single-rod measuring chains in different designs, which are manufactured using precision mechanical manufacturing and assembling technologies. The paper describes a microsystem technology approach for the fabrication of miniaturized electrochemical sensors. The ceramic HTCC (high-temperature co-fired ceramic) and LTCC (low-temperature co-fired ceramic) multilayer technology enables suitable processes for the manufacturing of robust and miniaturized sensor arrays with a high functional density. Design, manufacture, and electrochemical performance of the novel ceramic multilayer-based sensor array are presented in the paper using various examples. An adapted material and process development was carried out for the sensitive functional films. Special thick-film pastes for the detection of the pH value as well as NH 4 + , K+ , Ca2+ , and Cu2+ ion concentrations in aqueous solutions were developed. Ion-sensitive thick-film membranes were deposited on a ceramic multilayer sensor platform by means of screen-printing. All ISEs, integrated in the sensor array, showed suitable electrochemical performances including a very quick response (several seconds) combined with a high sensitivity (exhibiting Nernstian behaviour) in the tested measuring range. The obtained sensitivities were around 57 mVper decade : for the pH sensor, 30 mVper decade for calcium, 53 mVper decade for potassium, and 57 mVper decade for ammonium. Depending on the application, different sensitive electrodes on the ceramic sensor array can be combined as required.
{"title":"Ceramic multilayer technology as a platform for miniaturized sensor arrays for water analysis","authors":"C. Feller, U. Partsch","doi":"10.5194/JSSS-10-83-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-83-2021","url":null,"abstract":"Abstract. Ion-selective electrodes (ISEs) have been proven particularly useful in water\u0000analysis. They are usually used as single-rod measuring chains in different\u0000designs, which are manufactured using precision mechanical manufacturing and\u0000assembling technologies. The paper describes a microsystem technology approach\u0000for the fabrication of miniaturized electrochemical sensors. The ceramic HTCC (high-temperature co-fired ceramic)\u0000and LTCC (low-temperature co-fired ceramic) multilayer technology enables suitable processes for the\u0000manufacturing of robust and miniaturized sensor arrays with a high functional\u0000density. Design, manufacture, and electrochemical performance of the novel\u0000ceramic multilayer-based sensor array are presented in the paper using various\u0000examples. An adapted material and process development was carried out for the\u0000sensitive functional films. Special thick-film pastes for the detection of the\u0000pH value as well as NH 4 + , K+ , Ca2+ ,\u0000and Cu2+ ion concentrations in aqueous solutions were\u0000developed. Ion-sensitive thick-film membranes were deposited on a ceramic\u0000multilayer sensor platform by means of screen-printing. All ISEs, integrated\u0000in the sensor array, showed suitable electrochemical performances including a\u0000very quick response (several seconds) combined with a high sensitivity\u0000(exhibiting Nernstian behaviour) in the tested measuring range. The obtained\u0000sensitivities were around 57 mVper decade : for the pH sensor,\u000030 mVper decade for calcium, 53 mVper decade for potassium,\u0000and 57 mVper decade for ammonium. Depending on the application,\u0000different sensitive electrodes on the ceramic sensor array can be combined as\u0000required.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45268864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Werner, J. Kita, M. Gollner, F. Linseis, R. Moos
Abstract. A novel measurement device for simultaneous high temperature measurements of the electrical conductivity and the Hall coefficient has been developed. Simulations were used to design a suitable screen-printed planar platinum heating structure that generates temperatures of up to 600 ∘ C by Joule heating. Simulations of the temperature distribution have been validated using thermal imaging. With the hardware setup of two permanent magnetic yoke systems with a magnetic flux density of ±760 mT, the electrical conductivity and the charge carrier densities of a silicon wafer and a gold film were measured, as examples of a typical semiconductor with low charge carrier densities but high mobility and a metal representing materials with very high charge carrier densities but moderate mobilities, respectively. Measurements were compared with data from the literature to validate the functionality of the novel, low-cost measurement device.
{"title":"Novel, low-cost device to simultaneously measure the electrical conductivity and the Hall coefficient from room temperature up to 600 °C","authors":"R. Werner, J. Kita, M. Gollner, F. Linseis, R. Moos","doi":"10.5194/JSSS-10-71-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-71-2021","url":null,"abstract":"Abstract. A novel measurement device for simultaneous high temperature measurements of the electrical conductivity and the Hall coefficient has been developed. Simulations were used to design a suitable screen-printed planar platinum heating structure that generates temperatures of up to 600 ∘ C by Joule heating. Simulations of the temperature distribution have been validated using thermal imaging. With the hardware setup of two permanent magnetic yoke systems with a magnetic flux density of ±760 mT, the electrical conductivity and the charge carrier densities of a silicon wafer and a gold film were measured, as examples of a typical semiconductor with low charge carrier densities but high mobility and a metal representing materials with very high charge carrier densities but moderate mobilities, respectively. Measurements were compared with data from the literature to validate the functionality of the novel, low-cost measurement device.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43446219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Felix Lehner, J. Roth, O. Hupe, Marc Kassubeck, B. Bergmann, P. Mánek, M. Magnor
Abstract. This paper presents a method of how to determine spatial angles of ionizing radiation incidence quickly, using a Timepix3 detector. This work focuses on the dosimetric applications where detectors and measured quantities show significant angle dependencies. A determined angle of incidence can be used to correct for the angle dependence of a planar Timepix3 detector. Up until now, only passive dosemeters have been able to provide a correct dose and preserve the corresponding incidence angle of the radiation. Unfortunately, passive dosemeters cannot provide this information in “real” time. In our special setup we were able to retrieve the spatial angles with a runtime of less than 600 ms. Employing the new Timepix3 detector enables the use of effective data analysis where the direction of incident radiation is computed from a simple photon event map. In order to obtain this angle, we combine the information extracted from the map with known 3D geometry surrounding the detector. Moreover, we analyze the computation time behavior, conditions and optimizations of the developed spatial angle calculation algorithm.
{"title":"Method for fast determination of the angle of ionizing radiation incidence from data measured by a Timepix3 detector","authors":"Felix Lehner, J. Roth, O. Hupe, Marc Kassubeck, B. Bergmann, P. Mánek, M. Magnor","doi":"10.5194/JSSS-10-63-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-63-2021","url":null,"abstract":"Abstract. This paper presents a method of how to determine spatial angles of ionizing radiation incidence quickly, using a Timepix3 detector. This work focuses on the dosimetric applications where detectors and measured quantities show significant angle dependencies. A determined angle of incidence can be used to correct for the angle dependence of a planar Timepix3 detector. Up until now, only passive dosemeters have been able to provide a correct dose and preserve the corresponding incidence angle of the radiation. Unfortunately, passive dosemeters cannot provide this information in “real” time. In our special setup we were able to retrieve the spatial angles with a runtime of less than 600 ms. Employing the new Timepix3 detector enables the use of effective data analysis where the direction of incident radiation is computed from a simple photon event map. In order to obtain this angle, we combine the information extracted from the map with known 3D geometry surrounding the detector. Moreover, we analyze the computation time behavior, conditions and optimizations of the developed spatial angle calculation algorithm.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48853253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Mathis, Dennis Vollberg, M. Langosch, Dirk Göttel, A. Lellig, G. Schultes
Abstract. An important property of high-precision mechanical sensors such as force transducers or torque sensors is the so-called creep error. It is defined as the signal deviation over time at a constant load. Since this signal deviation results in a reduced accuracy of the sensor, it is beneficial to minimize the creep error. Many of these sensors consist of a metallic spring element and strain gauges. In order to realize a sensor with a creep error of almost zero, it is necessary to compensate for the creep behavior of the metallic spring element. This can be achieved by creep adjustment of the used strain gauges. Unlike standard metal foil strain gauges with a gauge factor of 2, a type of strain gauges based on sputter-deposited NiCr -carbon thin films on polymer substrates offers the advantage of an improved gauge factor of about 10. However, for this type of strain gauge, creep adjustment by customary methods is not possible. In order to remedy this disadvantage, a thorough creep analysis is carried out. Five major influences on the creep error of force transducers equipped with NiCr -carbon thin-film strain gauges are examined, namely, the material creep of the metallic spring element (1), the creep (relaxation) of the polymer substrate (2), the composition of the thin film (3), the strain transfer to the thin film (4), and the kind of strain field on the surface of the transducer (5). Consequently, we present two applicable methods for creep adjustment of NiCr -carbon thin- film strain gauges. The first method addresses the intrinsic creep behavior of the thin film by a modification of the film composition. With increasing Cr content (at the expense of Ni, the intrinsic negative creep error can be shifted towards zero. The second method is not based on the thin film itself but rather on a modification of the strain transfer from the polyimide carrier to the thin film. This is achieved by controlled cutting of well-defined deep trenches into the polymer substrate via a picosecond laser.
{"title":"Creep adjustment of strain gauges based on granular NiCr-carbon thin films","authors":"M. Mathis, Dennis Vollberg, M. Langosch, Dirk Göttel, A. Lellig, G. Schultes","doi":"10.5194/JSSS-10-53-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-53-2021","url":null,"abstract":"Abstract. An important property of high-precision mechanical sensors such as force transducers or torque sensors is the so-called creep error. It is defined as the signal deviation over time at a constant load. Since this signal deviation results in a reduced accuracy of the sensor, it is beneficial to minimize the creep error. Many of these sensors consist of a metallic spring element and strain gauges. In order to realize a sensor with a creep error of almost zero, it is necessary to compensate for the creep behavior of the metallic spring element. This can be achieved by creep adjustment of the used strain gauges. Unlike standard metal foil strain gauges with a gauge factor of 2, a type of strain gauges based on sputter-deposited NiCr -carbon thin films on polymer substrates offers the advantage of an improved gauge factor of about 10. However, for this type of strain gauge, creep adjustment by customary methods is not possible. In order to remedy this disadvantage, a thorough creep analysis is carried out. Five major influences on the creep error of force transducers equipped with NiCr -carbon thin-film strain gauges are examined, namely, the material creep of the metallic spring element (1), the creep (relaxation) of the polymer substrate (2), the composition of the thin film (3), the strain transfer to the thin film (4), and the kind of strain field on the surface of the transducer (5). Consequently, we present two applicable methods for creep adjustment of NiCr -carbon thin- film strain gauges. The first method addresses the intrinsic creep behavior of the thin film by a modification of the film composition. With increasing Cr content (at the expense of Ni, the intrinsic negative creep error can be shifted towards zero. The second method is not based on the thin film itself but rather on a modification of the strain transfer from the polyimide carrier to the thin film. This is achieved by controlled cutting of well-defined deep trenches into the polymer substrate via a picosecond laser.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47332322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Yurchenko, H. Pernau, L. Engel, B. Bierer, M. Jägle, J. Wöllenstein
Abstract. Differential thermal analysis (DTA) was used to examine the effect of the particle size and morphology of cobalt (III/IV) oxide ( Co3O4 ) on its thermal response under exposure to methane (1 vol % in dry synthetic air), which is a relevant gas for the detection of combustible gases. The DTA response results from the catalytic oxidation of methane, and its characteristics should correlate with the pellistor response. Co3O4 samples differing in particle size and morphology were produced by ball milling (top-down technique) or were synthesized from precursor molecules by precipitation (bottom-up technique). The investigations carried out in dry air and a temperature range between 250 and 450 ∘ C reveal that both particle size and particle shape have a considerable effect on thermal response, since the resulting layer structures and the associated surface area available for gas interaction differ. The Co3O4 catalyst, with small particles and an irregular shape, exhibits significantly higher response than milled Co3O4 samples. Comparison of DTA with the mass spectroscopy signal of CO2 evolved by the reaction verified a certain analogy between DTA measurements and the response produced by a pellistor.
{"title":"Impact of particle size and morphology of cobalt oxide on the thermal response to methane examined by thermal analysis","authors":"O. Yurchenko, H. Pernau, L. Engel, B. Bierer, M. Jägle, J. Wöllenstein","doi":"10.5194/JSSS-10-37-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-37-2021","url":null,"abstract":"Abstract. Differential thermal analysis (DTA) was used to examine the effect of the particle size and morphology of cobalt (III/IV) oxide ( Co3O4 ) on its thermal response under exposure to methane (1 vol % in dry synthetic air), which is a relevant gas for the detection of combustible gases. The DTA response results from the catalytic oxidation of methane, and its characteristics should correlate with the pellistor response. Co3O4 samples differing in particle size and morphology were produced by ball milling (top-down technique) or were synthesized from precursor molecules by precipitation (bottom-up technique). The investigations carried out in dry air and a temperature range between 250 and 450 ∘ C reveal that both particle size and particle shape have a considerable effect on thermal response, since the resulting layer structures and the associated surface area available for gas interaction differ. The Co3O4 catalyst, with small particles and an irregular shape, exhibits significantly higher response than milled Co3O4 samples. Comparison of DTA with the mass spectroscopy signal of CO2 evolved by the reaction verified a certain analogy between DTA measurements and the response produced by a pellistor.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48801177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Bifano, A. Fischerauer, A. Liedtke, G. Fischerauer
Abstract. The global economy consumes an estimated 4×1010 t of sand per year, with only 2×1010 t of sand being reproduced by natural sedimentation (Gotze and Gobbels, 2017; Peduzzi, 2014). Among other things, sand is also used as a basic material for the production of molds and cores in the foundry industry. The consumption and the economic as well as ecological savings' potential in this area of application can be appreciated by way of an example: the environmental certificate of a single, albeit big German foundry (5160 employees) can be consulted, which states that 39 820 t of sand for casting molds had to be purchased in 2017 (Denes, 2018). In order to avoid having to dispose of the used sand in landfills and to reduce the use of new sand, it is therefore advantageous to renew the used sand in a so-called regeneration process and reuse it as a substitute for new sand in the production of molds and cores. It would be very advantageous if the condition of molding materials (sand–binder systems) in regenerator units could be monitored in real time because of the economic and ecological advantages of a monitored and optimized regeneration process. This work presents the results of investigations in this direction. The objects of investigation in this work are typical molding materials in the foundry industry, e.g., quartz sand, chromite sand, and bentonite as a binder, which are measured impedimetrically with the help of a plate capacitor measuring cell which is connected to an LCR meter (Agilent E4980A). The impedance of the filled capacitor is measured in a frequency range from 1.2 kHz to 1 MHz, containing 123 frequency points. The aim of this research is to work out if the mentioned substances can be measured with the presented measuring method and classified on the basis of impedance characteristics and thus whether impedance spectroscopy can be considered for process monitoring in the molding industry. It is shown that the condition monitoring can possibly be based on impedance spectroscopy because the resulting curves are characteristic of the material used. New and used sands as well as two-component mixtures of sands and binders showed a systematic behavior, which allows the sand or the composition of the mixture to be identified (classified) in the future. The examination of the scatter of the measurement results shows that the impedance data obtained with this method can be measured reproducibly. A descriptive model for multi-component systems is developed in order to be able to interpret the impedance scatter results and their representation in Nyquist plots. From this model, the filling density of the measurement cell and the density of conduction paths can be extracted as essential influence quantities.
{"title":"Characterization of sand and sand–binder systems from the foundry industry with electrical impedance spectroscopy","authors":"L. Bifano, A. Fischerauer, A. Liedtke, G. Fischerauer","doi":"10.5194/JSSS-10-43-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-43-2021","url":null,"abstract":"Abstract. The global economy consumes an estimated 4×1010 t of sand\u0000per year, with only 2×1010 t of sand being reproduced by natural\u0000sedimentation (Gotze and Gobbels, 2017; Peduzzi, 2014). Among other things, sand\u0000is also used as a basic material for the production of molds and cores in\u0000the foundry industry. The consumption and the economic as well as ecological\u0000savings' potential in this area of application can be appreciated by way of\u0000an example: the environmental certificate of a single, albeit big German\u0000foundry (5160 employees) can be consulted, which states that 39 820 t of\u0000sand for casting molds had to be purchased in 2017 (Denes, 2018). In order\u0000to avoid having to dispose of the used sand in landfills and to reduce the use of new sand,\u0000it is therefore advantageous to renew the used sand in a so-called\u0000regeneration process and reuse it as a substitute for new sand in the\u0000production of molds and cores. It would be very advantageous if the\u0000condition of molding materials (sand–binder systems) in regenerator units\u0000could be monitored in real time because of the economic and ecological\u0000advantages of a monitored and optimized regeneration process. This work\u0000presents the results of investigations in this direction. The objects of\u0000investigation in this work are typical molding materials in the foundry\u0000industry, e.g., quartz sand, chromite sand, and bentonite as a binder, which\u0000are measured impedimetrically with the help of a plate capacitor measuring\u0000cell which is connected to an LCR meter (Agilent E4980A). The impedance of\u0000the filled capacitor is measured in a frequency range from 1.2 kHz to 1 MHz,\u0000containing 123 frequency points. The aim of this research is to work out if\u0000the mentioned substances can be measured with the presented measuring method\u0000and classified on the basis of impedance characteristics and thus whether impedance\u0000spectroscopy can be considered for process monitoring in the molding\u0000industry. It is shown that the condition monitoring can possibly be based on\u0000impedance spectroscopy because the resulting curves are characteristic of\u0000the material used. New and used sands as well as two-component mixtures of\u0000sands and binders showed a systematic behavior, which allows the sand or the\u0000composition of the mixture to be identified (classified) in the future. The\u0000examination of the scatter of the measurement results shows that the\u0000impedance data obtained with this method can be measured reproducibly. A\u0000descriptive model for multi-component systems is developed in order to be\u0000able to interpret the impedance scatter results and their representation in\u0000Nyquist plots. From this model, the filling density of the measurement cell\u0000and the density of conduction paths can be extracted as essential influence\u0000quantities.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48376036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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