Pub Date : 2021-01-01DOI: 10.5194/jsss-10-207-2021
S. Schramm, J. Ebert, J. Rangel, R. Schmoll, A. Kroll
Abstract. The geometric calibration of cameras becomes necessary when images should be undistorted, geometric image information is needed or data from more than one camera have to be fused. This process is often done using a target with a checkerboard or circular pattern and a given geometry. In this work, a coded checkerboard target for thermal imaging cameras and the corresponding image processing algorithm for iterative feature detection are presented. It is shown that, due in particular to the resulting better feature detectability at image borders, lower uncertainties in the estimation of the distortion parameters are achieved.
{"title":"Iterative feature detection of a coded checkerboard target for the geometric calibration of infrared cameras","authors":"S. Schramm, J. Ebert, J. Rangel, R. Schmoll, A. Kroll","doi":"10.5194/jsss-10-207-2021","DOIUrl":"https://doi.org/10.5194/jsss-10-207-2021","url":null,"abstract":"Abstract. The geometric calibration of cameras becomes necessary when images should be undistorted, geometric image information is needed or data from more than one camera have to be fused. This process is often done using a target with a checkerboard or circular pattern and a given geometry. In this work, a coded checkerboard target for thermal imaging cameras and the corresponding image processing algorithm for iterative feature detection are presented. It is shown that, due in particular to the resulting better feature detectability at image borders, lower uncertainties in the estimation of the distortion parameters are achieved.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70626766","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 : 2021-01-01DOI: 10.5194/jsss-10-193-2021
Q. Zaman, S. Alraho, A. König
Abstract. This paper aims to improve the traditional calibration method for reconfigurable self-X (self-calibration, self-healing, self-optimize, etc.) sensor interface readout circuit for industry 4.0. A cost-effective test stimulus is applied to the device under test, and the transient response of the system is analyzed to correlate the circuit's characteristics parameters. Due to complexity in the search and objective space of the smart sensory electronics, a novel experience replay particle swarm optimization (ERPSO) algorithm is being proposed and proved a better-searching capability than some currently well-known PSO algorithms. The newly proposed ERPSO expanded the selection producer of the classical PSO by introducing an experience replay buffer (ERB) intending to reduce the probability of trapping into the local minima. The ERB reflects the archive of previously visited global best particles, while its selection is based upon an adaptive epsilon greedy method in the velocity updating model. The performance of the proposed ERPSO algorithm is verified by using eight different popular benchmarking functions. Furthermore, an extrinsic evaluation of the ERPSO algorithm is also examined on a reconfigurable wide swing indirect current-feedback instrumentation amplifier (CFIA). For the later test, we proposed an efficient optimization procedure by using total harmonic distortion analyses of CFIA output to reduce the total number of measurements and save considerable optimization time and cost. The proposed optimization methodology is roughly 3 times faster than the classical optimization process. The circuit is implemented by using Cadence design tools and CMOS 0.35 µm technology from Austria Microsystems (AMS). The efficiency and robustness are the key features of the proposed methodology toward implementing reliable sensory electronic systems for industry 4.0 applications.
{"title":"Efficient transient testing procedure using a novel experience replay particle swarm optimizer for THD-based robust design and optimization of self-X sensory electronics in industry 4.0","authors":"Q. Zaman, S. Alraho, A. König","doi":"10.5194/jsss-10-193-2021","DOIUrl":"https://doi.org/10.5194/jsss-10-193-2021","url":null,"abstract":"Abstract. This paper aims to improve the traditional calibration method for reconfigurable self-X (self-calibration, self-healing, self-optimize, etc.) sensor interface readout circuit for industry 4.0. A cost-effective test stimulus is applied to the device under test, and the transient response of the system is analyzed to correlate the circuit's characteristics parameters. Due to complexity in the search and objective space of the smart sensory electronics, a novel experience replay particle swarm optimization (ERPSO) algorithm is being proposed and proved a better-searching capability than some currently well-known PSO algorithms. The newly proposed ERPSO expanded the selection producer of the classical PSO by introducing an experience replay buffer (ERB) intending to reduce the probability of trapping into the local minima. The ERB reflects the archive of previously visited global best particles, while its selection is based upon an adaptive epsilon greedy method in the velocity updating model. The performance of the proposed ERPSO algorithm is verified by using eight different popular benchmarking functions. Furthermore, an extrinsic evaluation of the ERPSO algorithm is also examined on a reconfigurable wide swing indirect current-feedback instrumentation amplifier (CFIA). For the later test, we proposed an efficient optimization procedure by using total harmonic distortion analyses of CFIA output to reduce the total number of measurements and save considerable optimization time and cost. The proposed optimization methodology is roughly 3 times faster than the classical optimization process. The circuit is implemented by using Cadence design tools and CMOS 0.35 µm technology from Austria Microsystems (AMS). The efficiency and robustness are the key features of the proposed methodology toward implementing reliable sensory electronic systems for industry 4.0 applications.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70626867","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. 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 – i.e., the non-uniformity of the pixel-to-pixel responsivity, the inhomogeneity equivalent temperature difference (IETD), the noise equivalent temperature difference (NETD), and the size-of-source effect (SSE) – are determined according to the requirements given in the series of Technical Directives VDI/VDE 5585. The measurements are performed with the camera calibration facility of the Physikalisch-Technische Bundesanstalt. The data reference method is applied for the determination and improvement of the non-uniformity, leading to an improved IETD for all three cameras. Finally, the cameras are calibrated according to the different procedures discussed in the VDI/VDE 5585 series. Results achieved with the different calibration procedures are compared for each type of camera and among the three cameras. An uncertainty budget for the calibration of each camera is given according to GUM (ISO, 1995) and VDI/VDE 5585.
{"title":"Metrological characterization and calibration of thermographic cameras for quantitative temperature measurement","authors":"S. König, B. Gutschwager, R. Taubert, J. Hollandt","doi":"10.5194/jsss-9-425-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-425-2020","url":null,"abstract":"Abstract. We present the metrological characterization and calibration of three different types of thermographic cameras for quantitative temperature\u0000measurement traceable to the International Temperature Scale (ITS-90). Relevant technical specifications – i.e., the non-uniformity of the pixel-to-pixel responsivity, the inhomogeneity equivalent temperature difference (IETD), the noise equivalent temperature difference (NETD), and the size-of-source effect (SSE) – are determined according to the requirements given in the series of Technical Directives VDI/VDE 5585. The\u0000measurements are performed with the camera calibration facility of the Physikalisch-Technische Bundesanstalt. The data reference method is applied for the determination and improvement of the non-uniformity, leading to an improved IETD for all three cameras. Finally, the cameras are calibrated\u0000according to the different procedures discussed in the VDI/VDE 5585 series. Results achieved with the different calibration procedures are compared\u0000for each type of camera and among the three cameras. An uncertainty budget for the calibration of each camera is given according to GUM (ISO, 1995)\u0000and VDI/VDE 5585.\u0000","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46609661","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}
T. Baur, M. Bastuck, Caroline Schultealbert, T. Sauerwald, A. Schütze
Abstract. Applications like air quality, fire detection and detection of explosives require selective and quantitative measurements in an ever-changing background of interfering gases. One main issue hindering the successful implementation of gas sensors in real-world applications is the lack of appropriate calibration procedures for advanced gas sensor systems. This article presents a calibration scheme for gas sensors based on statistically distributed gas profiles with unique randomized gas mixtures. This enables a more realistic gas sensor calibration including masking effects and other gas interactions which are not considered in classical sequential calibration. The calibration scheme is tested with two different metal oxide semiconductor sensors in temperature-cycled operation using indoor air quality as an example use case. The results are compared to a classical calibration strategy with sequentially increasing gas concentrations. While a model trained with data from the sequential calibration performs poorly on the more realistic mixtures, our randomized calibration achieves significantly better results for the prediction of both sequential and randomized measurements for, for example, acetone, benzene and hydrogen. Its statistical nature makes it robust against overfitting and well suited for machine learning algorithms. Our novel method is a promising approach for the successful transfer of gas sensor systems from the laboratory into the field. Due to the generic approach using concentration distributions the resulting performance tests are versatile for various applications.
{"title":"Random gas mixtures for efficient gas sensor calibration","authors":"T. Baur, M. Bastuck, Caroline Schultealbert, T. Sauerwald, A. Schütze","doi":"10.5194/jsss-9-411-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-411-2020","url":null,"abstract":"Abstract. Applications like air quality, fire detection and\u0000detection of explosives require selective and quantitative measurements in\u0000an ever-changing background of interfering gases. One main issue hindering\u0000the successful implementation of gas sensors in real-world applications is\u0000the lack of appropriate calibration procedures for advanced gas sensor\u0000systems. This article presents a calibration scheme for gas sensors based on\u0000statistically distributed gas profiles with unique randomized gas mixtures.\u0000This enables a more realistic gas sensor calibration including masking\u0000effects and other gas interactions which are not considered in classical\u0000sequential calibration. The calibration scheme is tested with two different\u0000metal oxide semiconductor sensors in temperature-cycled operation using\u0000indoor air quality as an example use case. The results are compared to a\u0000classical calibration strategy with sequentially increasing gas\u0000concentrations. While a model trained with data from the sequential\u0000calibration performs poorly on the more realistic mixtures, our randomized\u0000calibration achieves significantly better results for the prediction of both\u0000sequential and randomized measurements for, for example, acetone, benzene and\u0000hydrogen. Its statistical nature makes it robust against overfitting and\u0000well suited for machine learning algorithms. Our novel method is a promising\u0000approach for the successful transfer of gas sensor systems from the\u0000laboratory into the field. Due to the generic approach using concentration\u0000distributions the resulting performance tests are versatile for various\u0000applications.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"9 1","pages":"411-424"},"PeriodicalIF":1.0,"publicationDate":"2020-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44684567","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. Capacitive pressure sensors are widely used in a variety of applications and are built using a variety of processes, including 3D printing technology. The use of this technology could lead us to a situation of large deflections, depending on the mechanical properties of the materials and the resolution of the machines used. This aspect is rarely reported in previous research works that focus on improving the performance in terms of linearity and sensitivity of these sensors. This paper describes the realization of relative pressure sensors designed as two different structures; the first one is the classical design composed of a single capacitor, while the second one is composed of two capacitors, designed in such a way that they both vary according to the applied pressure but in opposite senses to each other. The purpose is to study in particular the performance of the second structure in the case of large deflections for the context of educational use. Polylactic acid (PLA) is used as the manufacturing material to print the sensors by means of a printer based on fused deposing modeling, while conductive materials are used to provide the electrical conductivity required for the printed sensors. The manufactured sensors were tested under pressure in the range of [0; 9] KPa. Compared to the performance obtained with the first structure, simulation and experimental results show that the second structure improves linearity and allows the sensitivity to be increased from a minimum of 9.98 × 10 - 2 pF/hPa to a minimum of 3.4 × 10 - 1 pF/hPa.
{"title":"Improvement of the performance of a capacitive relative pressure sensor: case of large deflections","authors":"Samia Achouch, F. Regragui, M. Gharbi","doi":"10.5194/jsss-9-401-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-401-2020","url":null,"abstract":"Abstract. Capacitive pressure sensors are widely used in a variety of\u0000applications and are built using a variety of processes, including 3D\u0000printing technology. The use of this technology could lead us to a situation\u0000of large deflections, depending on the mechanical properties of the\u0000materials and the resolution of the machines used. This aspect is rarely reported\u0000in previous research works that focus on improving the performance in\u0000terms of linearity and sensitivity of these sensors. This paper describes\u0000the realization of relative pressure sensors designed as two different\u0000structures; the first one is the classical design composed of a single\u0000capacitor, while the second one is composed of two capacitors, designed in\u0000such a way that they both vary according to the applied pressure but in\u0000opposite senses to each other. The purpose is to study in particular the\u0000performance of the second structure in the case of large deflections for\u0000the context of educational use. Polylactic acid (PLA) is used as the manufacturing material to print the\u0000sensors by means of a printer based on fused deposing modeling, while\u0000conductive materials are used to provide the electrical conductivity\u0000required for the printed sensors. The manufactured sensors were tested under\u0000pressure in the range of [0; 9] KPa. Compared to the performance obtained\u0000with the first structure, simulation and experimental results show that the\u0000second structure improves linearity and allows the sensitivity to be increased from a minimum of 9.98 × 10 - 2 pF/hPa to a minimum of 3.4 × 10 - 1 pF/hPa.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"9 1","pages":"401-409"},"PeriodicalIF":1.0,"publicationDate":"2020-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44799085","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. The acidities of any given solvent or mixtures thereof can be compared by pH measurements on a unified scale, so-called pH abs H 2 O measurements. The method is quite new and has not been characterized with respect to metrological criteria to date. Metal solid-contact glass electrode half-cells, three commercial, conventional glass electrode half-cells with inner liquid filling and one pair of combined electrodes were used to investigate the stability of the measurement and the reproducibility of pH abs H 2 O results of ethanol mixtures with water. All electrodes are suitable for unified acidity measurements in standard aqueous buffers. In ethanol mixtures, the combined electrodes were found to be unsuitable. The half-cell electrodes can be reasonably used only in buffered solutions.
{"title":"Glass electrode half-cells for measuring unified pH in ethanol–water mixtures","authors":"A. Heering, F. Bastkowski, S. Seitz","doi":"10.5194/jsss-9-383-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-383-2020","url":null,"abstract":"Abstract. The acidities of any given solvent or mixtures thereof can be compared by pH measurements on a unified scale, so-called pH abs H 2 O measurements. The method is quite new and has not been characterized with respect to metrological criteria to date. Metal solid-contact glass electrode half-cells, three commercial, conventional glass electrode half-cells with inner liquid filling and one pair of combined electrodes were used to investigate the stability of the measurement and the reproducibility of pH abs H 2 O results of ethanol mixtures with water. All electrodes are suitable for unified acidity measurements in standard aqueous buffers. In ethanol mixtures, the combined electrodes were found to be unsuitable. The half-cell electrodes can be reasonably used only in buffered solutions.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"9 1","pages":"383-389"},"PeriodicalIF":1.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46503000","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}
D. Istrate, D. Amaripadath, Etienne Toutain, R. Roche, F. Gao
Abstract. The necessity of measuring harmonic emissions between 2 and 150 kHz is outlined by several standard committees and electrical utilities. This paper presents a measurement system and its traceable characterization designed to acquire and analyse voltages up to 230 V and currents up to 100 A with harmonics up to 150 kHz that may occur in smart grids. The uncertainty estimation is carried out and described in detail for both the fundamental and supraharmonics components. From a metrological point of view, ensuring the traceability of current measurements for frequencies higher than 100 kHz and dealing with the complexity of uncertainty determination are bottlenecks related to supraharmonics measurements that this paper proposes an approach to deal with.
{"title":"Traceable measurements of harmonic (2 to 150) kHz emissions in smart grids: uncertainty calculation","authors":"D. Istrate, D. Amaripadath, Etienne Toutain, R. Roche, F. Gao","doi":"10.5194/jsss-9-375-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-375-2020","url":null,"abstract":"Abstract. The necessity of measuring harmonic emissions between 2 and 150 kHz is outlined by several standard committees and electrical utilities. This paper presents a measurement system and its traceable characterization designed to acquire and analyse voltages up to 230 V and currents up to 100 A with harmonics up to 150 kHz that may occur in smart grids. The uncertainty estimation is carried out and described in detail for both the fundamental and supraharmonics components. From a metrological point of view, ensuring the traceability of current measurements for frequencies higher than 100 kHz and dealing with the complexity of uncertainty determination are bottlenecks related to supraharmonics measurements that this paper proposes an approach to deal with.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"9 1","pages":"375-381"},"PeriodicalIF":1.0,"publicationDate":"2020-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42700173","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. Electrical assemblies are the core of many electronic devices and therefore represent a crucial part of the overall product, which must be carefully checked before integration into its functional environment. For this reason, automatic optical inspection systems are required in electronic manufacturing to detect visible errors in products at an early stage. In particular, the automotive electronics production area is one of the sectors in which quality assurance has uppermost priority, as undetected defects can pose a danger to life. However, most optical inspection processes still have error slippage rates, which are responsible for delivering faulty electrical assemblies to customers. Therefore, this article shows how an application strategy of deep learning, based on neural networks, can be combined with an automatic optical inspection system to further increase the recognition accuracy of the process. The additional use of artificial intelligence supported classification systems provides a way to find out the exact details about the manufacturing-related errors of electrical assemblies. However, due to the high number of different error categories, a single classification algorithm is usually not sufficient to provide reliable visual inspection results with high robustness against error slip. For this reason, a hierarchical model with multiple classifiers is proposed in this article. The principle is based on the hierarchical description of the quality status and fault types using several combined neural networks. In this context, the original classification task is distributed over different subnetworks. These subnetworks, which interact as an overall model, only verify certain error and quality features of the electrical assemblies, which means that higher recognition accuracy and robustness can be achieved compared to a single network.
{"title":"Intelligent fault detection of electrical assemblies using hierarchical convolutional networks for supporting automatic optical inspection systems","authors":"Alida Ilse Maria Schwebig, R. Tutsch","doi":"10.5194/jsss-9-363-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-363-2020","url":null,"abstract":"Abstract. Electrical assemblies are the core of many electronic devices and therefore represent a crucial part of the overall product, which must be carefully checked before integration into its functional environment. For this reason, automatic optical inspection systems are required in electronic manufacturing to detect visible errors in products at an early stage. In particular, the automotive electronics production area is one of the sectors in which quality assurance has uppermost priority, as undetected defects can pose a danger to life. However, most optical inspection processes still have error slippage rates, which are responsible for delivering faulty electrical assemblies to customers. Therefore, this article shows how an application strategy of deep learning, based on neural networks, can be combined with an automatic optical inspection system to\u0000further increase the recognition accuracy of the process. The additional use of artificial intelligence supported classification systems provides a way to find out the exact details about the manufacturing-related errors of electrical assemblies. However, due to the\u0000high number of different error categories, a single classification algorithm\u0000is usually not sufficient to provide reliable visual inspection results with\u0000high robustness against error slip. For this reason, a hierarchical model\u0000with multiple classifiers is proposed in this article. The principle is\u0000based on the hierarchical description of the quality status and fault types\u0000using several combined neural networks. In this context, the original\u0000classification task is distributed over different subnetworks. These\u0000subnetworks, which interact as an overall model, only verify certain error\u0000and quality features of the electrical assemblies, which means that higher\u0000recognition accuracy and robustness can be achieved compared to a single\u0000network.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"9 1","pages":"363-374"},"PeriodicalIF":1.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47766073","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}
A. Ruchets, N. Donker, J. Zosel, D. Schönauer-Kamin, R. Moos, U. Guth, M. Mertig
Abstract. Solid electrolyte gas sensors (SESs) based on yttria-stabilized zirconia (YSZ) are suitable to detect traces of redox components in inert gases. Usually, their signals are generated as a voltage between two electrodes at open circuit potential or as a current flowing between constantly polarized electrodes. In these rather stationary modes of operation, SESs often lack the desired selectivity. This drawback can be circumvented if SESs are operated in dynamic electrochemical modes that utilize the differences of electrode kinetics for single components to distinguish between them. Accordingly, this contribution is directed to the investigation of cyclic voltammetry and square-wave voltammetry as methods to improve the selectivity of SESs. For this, a commercial SES of the type “sample gas, Pt | YSZ | Pt, air” was exposed to mixtures containing NO and O2 in N2 in the temperature range between 550 and 750 ∘ C. On cyclic voltammograms (CVs), NO-related peaks occur in the cathodic direction at polarization voltages between −0.3 and −0.6 V at scan rates between 100 and 2000 mV s −1 and temperatures between 550 and 750 ∘ C. Their heights depend on the NO concentration, on the temperature and on the scan rate, providing a lower limit of detection below 10 ppmv, with the highest sensitivity at 700 ∘ C. The O2 -related peaks, appearing also in the cathodic direction between −0.1 and −0.3 V at scan rates between 100 and 5000 mV s −1 , are well separated from the NO-related peaks if the scan rate does not exceed 2000 mV s −1 . Square-wave voltammograms (SWVs) obtained at a pulse frequency of 5 Hz, pulses of 0.1 mV and steps of 5 mV in the polarization range from 0 to −0.6 V also exhibit NO-related peaks at polarization voltages between −0.3 and −0.45 V compared to the Pt–air (platinum–air) electrode. In the temperature range between 650 and 750 ∘ C the highest NO sensitivity was found at 700 ∘ C. O2 -related peaks arise in the cathodic direction between −0.12 and −0.16 V, increase with temperature and do not depend on the concentration of NO. Since capacitive currents are suppressed with square-wave voltammetry, this method provides improved selectivity. In contrast to cyclic voltammetry, a third peak was found with square-wave voltammetry at −0.48 V and a temperature of 750 ∘ C. This peak does not depend on the NO concentration. It is assumed that this peak is due to the depletion of an oxide layer on the electrode surface. The results prove the selective detection of NO and O2 with SESs operated with both cyclic voltammetry and square-wave voltammetry.
{"title":"Cyclic and square-wave voltammetry for selective simultaneous NO and O2 gas detection by means of solid electrolyte sensors","authors":"A. Ruchets, N. Donker, J. Zosel, D. Schönauer-Kamin, R. Moos, U. Guth, M. Mertig","doi":"10.5194/jsss-9-355-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-355-2020","url":null,"abstract":"Abstract. Solid electrolyte gas sensors (SESs) based on\u0000yttria-stabilized zirconia (YSZ) are suitable to detect traces of redox components\u0000in inert gases. Usually, their signals are generated as a voltage between\u0000two electrodes at open circuit potential or as a current flowing between\u0000constantly polarized electrodes. In these rather stationary modes of\u0000operation, SESs often lack the desired selectivity. This drawback can be\u0000circumvented if SESs are operated in dynamic electrochemical modes that\u0000utilize the differences of electrode kinetics for single components to\u0000distinguish between them. Accordingly, this contribution is directed to the\u0000investigation of cyclic voltammetry and square-wave voltammetry\u0000as methods to improve the selectivity of SESs. For this, a commercial SES of the type “sample gas, Pt | YSZ | Pt, air” was exposed to mixtures containing NO and O2 in\u0000 N2 in the temperature range between 550 and 750 ∘ C. On cyclic voltammograms (CVs), NO-related peaks occur in the cathodic direction\u0000at polarization voltages between −0.3 and −0.6 V at scan rates between\u0000100 and 2000 mV s −1 and temperatures between 550 and 750 ∘ C.\u0000Their heights depend on the NO concentration, on the temperature and on the\u0000scan rate, providing a lower limit of detection below 10 ppmv, with the\u0000highest sensitivity at 700 ∘ C. The O2 -related peaks,\u0000appearing also in the cathodic direction between −0.1 and −0.3 V at scan\u0000rates between 100 and 5000 mV s −1 , are well separated from the\u0000NO-related peaks if the scan rate does not exceed 2000 mV s −1 . Square-wave voltammograms (SWVs) obtained at a pulse frequency of 5 Hz, pulses of 0.1 mV and\u0000steps of 5 mV in the polarization range from 0 to −0.6 V also exhibit\u0000NO-related peaks at polarization voltages between −0.3 and −0.45 V\u0000compared to the Pt–air (platinum–air) electrode. In the temperature range between 650 and\u0000750 ∘ C the highest NO sensitivity was found at 700 ∘ C.\u0000 O2 -related peaks arise in the cathodic direction between −0.12 and −0.16 V,\u0000increase with temperature and do not depend on the concentration of NO.\u0000Since capacitive currents are suppressed with square-wave voltammetry, this method provides\u0000improved selectivity. In contrast to cyclic voltammetry, a third peak was found with square-wave voltammetry at\u0000 −0.48 V and a temperature of 750 ∘ C. This peak does not depend on the\u0000NO concentration. It is assumed that this peak is due to the depletion of an\u0000oxide layer on the electrode surface. The results prove the selective\u0000detection of NO and O2 with SESs operated with both cyclic voltammetry and square-wave voltammetry.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"9 1","pages":"355-362"},"PeriodicalIF":1.0,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48623572","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. Plastic waste is one of the biggest growing factors contributing to environmental pollution. So far there has been no established method to detect and identify plastics in environmental matrices. Thus, a method based on their characteristic fluorescence behavior is used to investigate whether plastics can be detected and identified in tap water under laboratory conditions. The experiments show that the identification of plastics as a function of water depth is possible. As the identification becomes more difficult with higher water depths, investigations with a highly sensitive imaging method were carried out to obtain an areal integration of the fluorescent light and thus better results.
{"title":"Detection of plastics in water based on their fluorescence behavior","authors":"Maximilian Wohlschlager, M. Versen","doi":"10.5194/jsss-9-337-2020","DOIUrl":"https://doi.org/10.5194/jsss-9-337-2020","url":null,"abstract":"Abstract. Plastic waste is one of the biggest growing factors\u0000contributing to environmental pollution. So far there has been no established\u0000method to detect and identify plastics in environmental matrices. Thus, a\u0000method based on their characteristic fluorescence behavior is used to\u0000investigate whether plastics can be detected and identified in tap water\u0000under laboratory conditions. The experiments show that the\u0000identification of plastics as a function of water depth is possible. As the\u0000identification becomes more difficult with higher water depths,\u0000investigations with a highly sensitive imaging method were carried out to\u0000obtain an areal integration of the fluorescent light and thus better\u0000results.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"9 1","pages":"337-343"},"PeriodicalIF":1.0,"publicationDate":"2020-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46125180","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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