Pub Date : 2025-12-18DOI: 10.1016/j.sna.2025.117413
Snezana M. Djuric , Georges Dubourg , Nikola M. Djuric
Plants are crucial for our system. However, climate change and the continuous emergence of abiotic stress factors emphasize the need for improved plant productivity and resilience to stress. Precision agriculture, reliant on long-term, accurate sensing technologies, is vital for optimizing agricultural productivity. Intelligent, thin film wearable sensors for plants seek to foster an intelligent agriculture system capable of optimizing plant productivity while addressing challenges posed by climate change and population growth. Water stress tolerance of plants is one of key aspects to challenge climate change. Leaf capacitance is one of key aspects related to leaf water status. In this study, we propose tattoo electrodes of the fractal design for leaf capacitance monitoring. Using simple fabrication steps, gold leaf tattoo electrodes were symmetrically transferred on the adaxial and abaxial surface of the leaf to form a capacitor with a leaf serving as a dielectric layer between the electrodes.
{"title":"Fractal-inspired capacitive electronic tattoo sensor: A flexible platform for leaf moisture monitoring","authors":"Snezana M. Djuric , Georges Dubourg , Nikola M. Djuric","doi":"10.1016/j.sna.2025.117413","DOIUrl":"10.1016/j.sna.2025.117413","url":null,"abstract":"<div><div>Plants are crucial for our system. However, climate change and the continuous emergence of abiotic stress factors emphasize the need for improved plant productivity and resilience to stress. Precision agriculture, reliant on long-term, accurate sensing technologies, is vital for optimizing agricultural productivity. Intelligent, thin film wearable sensors for plants seek to foster an intelligent agriculture system capable of optimizing plant productivity while addressing challenges posed by climate change and population growth. Water stress tolerance of plants is one of key aspects to challenge climate change. Leaf capacitance is one of key aspects related to leaf water status. In this study, we propose tattoo electrodes of the fractal design for leaf capacitance monitoring. Using simple fabrication steps, gold leaf tattoo electrodes were symmetrically transferred on the adaxial and abaxial surface of the leaf to form a capacitor with a leaf serving as a dielectric layer between the electrodes.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117413"},"PeriodicalIF":4.9,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-18DOI: 10.1016/j.sna.2025.117408
Ali BashiriNezhad , Milad Esfandiar , Seyed Mostafa Hosseinalipour , Seyedeh Sarah Salehi
This study describes the creation and validation of an advanced liquid crystal (LC)-based optical detection system used for the precise and selective measurement of lactic acid (LA) and sodium chloride (NaCl) levels in aqueous solutions. The experimental design incorporated a tunable RGB light source, cross-polarized optics, and a digital microscope for capturing optical shifts within nematic 5CB LCs. A series of controlled optical measurements were performed using deionized water solutions of differing concentrations. LC interactions were observed and recorded based on colorimetric and intensity shifts. Analysis of RGB and grayscale image data revealed unique optical patterns correlating with analyte type and concentration. Sensitivity of the green and blue optical channels was found to be critically important based on calibration curves, which confirmed a concentration-dependent response. Linear regression, random forest, and XGBoost machine learning (ML) algorithms were employed for quantitative prediction on the RGB dataset. Among the tested models, linear regression achieved the highest predictive accuracy, with R² values of 0.98 for NaCl and 0.99 for LA. This proposed system shows substantial utility in biomedical and environmental contexts by enabling precise analyte discrimination and real-time concentration measurement. This framework provides a robust basis for future progress in LC sensor technology, improving diagnostic precision and facilitating the detection of multiple analytes within intricate systems like biological fluids.
{"title":"Machine learning assisted detection of lactic acid and sodium chloride in aqueous solutions using crystal-based polarized imaging","authors":"Ali BashiriNezhad , Milad Esfandiar , Seyed Mostafa Hosseinalipour , Seyedeh Sarah Salehi","doi":"10.1016/j.sna.2025.117408","DOIUrl":"10.1016/j.sna.2025.117408","url":null,"abstract":"<div><div>This study describes the creation and validation of an advanced liquid crystal (LC)-based optical detection system used for the precise and selective measurement of lactic acid (LA) and sodium chloride (NaCl) levels in aqueous solutions. The experimental design incorporated a tunable RGB light source, cross-polarized optics, and a digital microscope for capturing optical shifts within nematic 5CB LCs. A series of controlled optical measurements were performed using deionized water solutions of differing concentrations. LC interactions were observed and recorded based on colorimetric and intensity shifts. Analysis of RGB and grayscale image data revealed unique optical patterns correlating with analyte type and concentration. Sensitivity of the green and blue optical channels was found to be critically important based on calibration curves, which confirmed a concentration-dependent response. Linear regression, random forest, and XGBoost machine learning (ML) algorithms were employed for quantitative prediction on the RGB dataset. Among the tested models, linear regression achieved the highest predictive accuracy, with R² values of 0.98 for NaCl and 0.99 for LA. This proposed system shows substantial utility in biomedical and environmental contexts by enabling precise analyte discrimination and real-time concentration measurement. This framework provides a robust basis for future progress in LC sensor technology, improving diagnostic precision and facilitating the detection of multiple analytes within intricate systems like biological fluids.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117408"},"PeriodicalIF":4.9,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.sna.2025.117411
Alif T , Kanwaljeet Garg , Deepak Joshi
Functional electrical stimulation offers a promising approach for restoring limb function in individuals with neurological disorders. Accurate sensor measurements are essential to ensure the safe and effective operation of closed-loop stimulus-based rehabilitation systems. Errors in joint angle measurements can lead to inaccurate stimulation estimation, compromising rehabilitation outcomes. We propose a dynamic linearization-based data-driven fault tolerance scheme that compensates for rotary encoder faults during limb movement using electrical stimulus. Unlike model-based approaches, the proposed scheme is entirely data-driven, overcoming the complexities associated with system modelling. The experiment with six healthy and one spinal cord-injury participant demonstrated an average (SD) root mean square error of 3.46º (1.50) during the desired knee trajectory tracking. In contrast, comparative analysis with a conventional model-independent approach without sensor faults offers an RMSE of 3.88º (1.28). Results (Man-Whitney U Test, p = 0.36) indicate that the proposed controller under sensor fault performs on par with a conventional model-independent controller without a sensor fault. The findings underscore the reliability and feasibility of the proposed adaptive fault-tolerant scheme for real-time stimulus-based rehabilitation, especially in scenarios where sensor faults present significant challenges.
{"title":"A data-driven sensor fault tolerance approach for functional electrical stimulation in healthy and spinal cord injury individuals","authors":"Alif T , Kanwaljeet Garg , Deepak Joshi","doi":"10.1016/j.sna.2025.117411","DOIUrl":"10.1016/j.sna.2025.117411","url":null,"abstract":"<div><div>Functional electrical stimulation offers a promising approach for restoring limb function in individuals with neurological disorders. Accurate sensor measurements are essential to ensure the safe and effective operation of closed-loop stimulus-based rehabilitation systems. Errors in joint angle measurements can lead to inaccurate stimulation estimation, compromising rehabilitation outcomes. We propose a dynamic linearization-based data-driven fault tolerance scheme that compensates for rotary encoder faults during limb movement using electrical stimulus. Unlike model-based approaches, the proposed scheme is entirely data-driven, overcoming the complexities associated with system modelling. The experiment with six healthy and one spinal cord-injury participant demonstrated an average (SD) root mean square error of 3.46º (1.50) during the desired knee trajectory tracking. In contrast, comparative analysis with a conventional model-independent approach without sensor faults offers an RMSE of 3.88º (1.28). Results (Man-Whitney U Test, p = 0.36) indicate that the proposed controller under sensor fault performs on par with a conventional model-independent controller without a sensor fault. The findings underscore the reliability and feasibility of the proposed adaptive fault-tolerant scheme for real-time stimulus-based rehabilitation, especially in scenarios where sensor faults present significant challenges.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117411"},"PeriodicalIF":4.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.sna.2025.117404
Zongjian Zhang , Zenghua Liu , Yang Zheng , Jidong Tan
Conventional electromagnetic acoustic transducers (EMATs) are limited by their large dimensions for high-precision, high-resolution defect detection applications. This study presents an improved EMAT design utilizing a spatial vertical winding coil (SVWC), where both simulation models and experimental investigations were conducted to optimize the performance of the transducer. The experimental results demonstrate that incorporating a shielding layer in the SVWC configuration effectively eliminates interference from upper wires, suppresses acoustic side lobes, and reduces the coil's spatial height, achieving significant miniaturization. Compared to conventional planar coil EMATs with identical dimensions, the SVWC-EMAT exhibits enhanced transduction efficiency, showing 4.85-fold and 11-fold increases in signal amplitude on aluminum and 20# steel substrates, respectively. The implemented SVWC-EMAT achieves a minimum coil width of 1.0 mm, when integrated with synthetic aperture focusing imaging, successfully detects 1.0 mm diameter defects while resolving adjacent defects with 1.0 mm edge-to-edge spacing. These findings establish an important foundation for developing compact EMAT arrays and advancing high-precision electromagnetic acoustic imaging techniques.
{"title":"Spatial vertical winding coil-EMAT: Miniaturized design with enhanced efficiency for high-resolution defect detection","authors":"Zongjian Zhang , Zenghua Liu , Yang Zheng , Jidong Tan","doi":"10.1016/j.sna.2025.117404","DOIUrl":"10.1016/j.sna.2025.117404","url":null,"abstract":"<div><div>Conventional electromagnetic acoustic transducers (EMATs) are limited by their large dimensions for high-precision, high-resolution defect detection applications. This study presents an improved EMAT design utilizing a spatial vertical winding coil (SVWC), where both simulation models and experimental investigations were conducted to optimize the performance of the transducer. The experimental results demonstrate that incorporating a shielding layer in the SVWC configuration effectively eliminates interference from upper wires, suppresses acoustic side lobes, and reduces the coil's spatial height, achieving significant miniaturization. Compared to conventional planar coil EMATs with identical dimensions, the SVWC-EMAT exhibits enhanced transduction efficiency, showing 4.85-fold and 11-fold increases in signal amplitude on aluminum and 20# steel substrates, respectively. The implemented SVWC-EMAT achieves a minimum coil width of 1.0 mm, when integrated with synthetic aperture focusing imaging, successfully detects 1.0 mm diameter defects while resolving adjacent defects with 1.0 mm edge-to-edge spacing. These findings establish an important foundation for developing compact EMAT arrays and advancing high-precision electromagnetic acoustic imaging techniques.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117404"},"PeriodicalIF":4.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.sna.2025.117407
Hakan Altuntaş , Mehmet Selçuk Arslan
Accurate temperature control is essential in domestic induction cooktops for energy efficiency and cooking performance. One of the most suitable ways to measure temperature within the domestic induction cooktops is by using non-contact temperature measurement techniques like infrared (IR) temperature sensors. A key challenge in non-contact IR temperature measurement is the reliance on the emissivity of the object, which can lead to significant errors when emissivity is unknown or variable. The emissivity of cooking vessel is influenced by surface properties, and its color, making precise measurement challenging. In this study, we developed an advanced sensor system capable of identifying the surface properties of cooking vessels, including color, allowing for the estimation of emissivity. This system enables accurate temperature measurement by adjusting the IR sensor’s readings based on the cooking vessel’s emissivity. The proposed method improves the accuracy of temperature measurement in domestic induction cooktops, leading to better temperature control and enhanced cooking results.
{"title":"Real-time emissivity estimation using a smart sensor system for infrared temperature measurement","authors":"Hakan Altuntaş , Mehmet Selçuk Arslan","doi":"10.1016/j.sna.2025.117407","DOIUrl":"10.1016/j.sna.2025.117407","url":null,"abstract":"<div><div>Accurate temperature control is essential in domestic induction cooktops for energy efficiency and cooking performance. One of the most suitable ways to measure temperature within the domestic induction cooktops is by using non-contact temperature measurement techniques like infrared (IR) temperature sensors. A key challenge in non-contact IR temperature measurement is the reliance on the emissivity of the object, which can lead to significant errors when emissivity is unknown or variable. The emissivity of cooking vessel is influenced by surface properties, and its color, making precise measurement challenging. In this study, we developed an advanced sensor system capable of identifying the surface properties of cooking vessels, including color, allowing for the estimation of emissivity. This system enables accurate temperature measurement by adjusting the IR sensor’s readings based on the cooking vessel’s emissivity. The proposed method improves the accuracy of temperature measurement in domestic induction cooktops, leading to better temperature control and enhanced cooking results.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117407"},"PeriodicalIF":4.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.sna.2025.117412
Wei Chen , Xiuchuan Jing , Zhuang Li , Yongxi Ma , Hongda Gu , Haiqing Miao , Zhong Wang , Guohe Wang
Attaching flexible resistive strain sensors to human skin enables response detection of behaviours towards real-time physiological monitoring. However, current flexible resistive strain sensors hinder themselves from practical applications due to their low sensitivity, small linear working range, and poor wearing comfort. In this research, a conductive thermoplastic polyurethane (TPU) membrane is fabricated using TEMPO modified nanocellulose (TNC) decorated with carbon quantum dots (CQDs) to prepare flexible highly sensitive, and breathable strain sensors. Results show that the mechanical property and strain response range of the TPU membrane is significantly enhanced by CQDs-TNC. The TPU membrane also exhibits the highest sensitivity (GF= 49.4 in the 30∼80 % strain range) and a wide response range (0–80 %). At 5 %wt of CQDs-TNC, the membrane displays the highest elongation at break (389.8 %) with maximum breaking stress approaching 9.7 MPa. The CQDs-TNC/TPU membrane exhibits fast response and recovery times (85 ms and 93 ms), low hysteresis (8.9 %), and excellent dynamic cyclic strain performance (1000 stretch/release cycles). The CQDs/TMC/TPU-resistive strain sensor (CTT-RSS) sensor well conforms to human joints, and accurately produces real-time regular resistance strain responses based on human movements. In all, this study contributes a novel research design for fabricating flexible and sensitive sensor to the development of smart textiles.
{"title":"Fabrication of flexible and sensitive resistance strain sensor by flexible TPU decorated with CQDs/TNC composite","authors":"Wei Chen , Xiuchuan Jing , Zhuang Li , Yongxi Ma , Hongda Gu , Haiqing Miao , Zhong Wang , Guohe Wang","doi":"10.1016/j.sna.2025.117412","DOIUrl":"10.1016/j.sna.2025.117412","url":null,"abstract":"<div><div>Attaching flexible resistive strain sensors to human skin enables response detection of behaviours towards real-time physiological monitoring. However, current flexible resistive strain sensors hinder themselves from practical applications due to their low sensitivity, small linear working range, and poor wearing comfort. In this research, a conductive thermoplastic polyurethane (TPU) membrane is fabricated using TEMPO modified nanocellulose (TNC) decorated with carbon quantum dots (CQDs) to prepare flexible highly sensitive, and breathable strain sensors. Results show that the mechanical property and strain response range of the TPU membrane is significantly enhanced by CQDs-TNC. The TPU membrane also exhibits the highest sensitivity (GF= 49.4 in the 30∼80 % strain range) and a wide response range (0–80 %). At 5 %wt of CQDs-TNC, the membrane displays the highest elongation at break (389.8 %) with maximum breaking stress approaching 9.7 MPa. The CQDs-TNC/TPU membrane exhibits fast response and recovery times (85 ms and 93 ms), low hysteresis (8.9 %), and excellent dynamic cyclic strain performance (1000 stretch/release cycles). The CQDs/TMC/TPU-resistive strain sensor (CTT-RSS) sensor well conforms to human joints, and accurately produces real-time regular resistance strain responses based on human movements. In all, this study contributes a novel research design for fabricating flexible and sensitive sensor to the development of smart textiles.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117412"},"PeriodicalIF":4.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.sna.2025.117405
Jianhua Wang , Shenhua Zhang , Yanxi Yang
In fringe projection profilometry (FPP), the captured fringes on highlight surface are often saturated. Traditional high dynamic range (HDR) methods require additional fringe projection or hardware assistance. In this paper, a hybrid network architecture that combines improved U-Net and generative adversarial networks (GAN) is proposed for saturation fringe self restoration without any assistance. Firstly, the encoder does not use pooling layer for downsampling, but instead achieves downsampling by increasing the stride of the convolutional layer from 1 to 2, which avoids the loss of detailed features caused by pooling processing. 4 × 4 convolution kernel increases the receptive field compared to U-Net's 3 × 3 convolution kernel. Secondly, the improved U-Net adopts asymmetric skip connection, which allows the decoder to gradually transition from higher-level abstract features to lower level detail features by utilizing the features of different layers of the encoder when restoring the image. Finally, the adversarial learning mechanism in GAN is adopted to optimize the performance of the generator and discriminator. The generator is responsible for generating more realistic images, while the discriminator is responsible for verifying whether the image is generated by the generator. In the process of mutual game, the ability to generate real images and the ability to discern are continuously improved until they reach a Nash equilibrium. The experimental results show that the fringe PSNR of the proposed GAN-U-Net has been significantly improved compared to that of U-Net, while the absolute phase RMSE is reduced by approximately 10.91 % −64.15 %.
{"title":"Deep learning-based high dynamic range 3D measurement: The combination of GAN and U-Net","authors":"Jianhua Wang , Shenhua Zhang , Yanxi Yang","doi":"10.1016/j.sna.2025.117405","DOIUrl":"10.1016/j.sna.2025.117405","url":null,"abstract":"<div><div>In fringe projection profilometry (FPP), the captured fringes on highlight surface are often saturated. Traditional high dynamic range (HDR) methods require additional fringe projection or hardware assistance. In this paper, a hybrid network architecture that combines improved U-Net and generative adversarial networks (GAN) is proposed for saturation fringe self restoration without any assistance. Firstly, the encoder does not use pooling layer for downsampling, but instead achieves downsampling by increasing the stride of the convolutional layer from 1 to 2, which avoids the loss of detailed features caused by pooling processing. 4 × 4 convolution kernel increases the receptive field compared to U-Net's 3 × 3 convolution kernel. Secondly, the improved U-Net adopts asymmetric skip connection, which allows the decoder to gradually transition from higher-level abstract features to lower level detail features by utilizing the features of different layers of the encoder when restoring the image. Finally, the adversarial learning mechanism in GAN is adopted to optimize the performance of the generator and discriminator. The generator is responsible for generating more realistic images, while the discriminator is responsible for verifying whether the image is generated by the generator. In the process of mutual game, the ability to generate real images and the ability to discern are continuously improved until they reach a Nash equilibrium. The experimental results show that the fringe PSNR of the proposed GAN-U-Net has been significantly improved compared to that of U-Net, while the absolute phase RMSE is reduced by approximately 10.91 % −64.15 %.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117405"},"PeriodicalIF":4.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.sna.2025.117401
Thomas Schweizer , Kapil Tagale , Henrik Nöbel , Andreas Schander , Michael J. Vellekoop
Controlled opening of sealed microsensors is crucial for their correct functioning. Often, sensors need to be protected from the environment until they are deployed. This could be against humidity, harmful gases or biological contamination. Fragments of the sealing membrane are not wanted on the sensing element after actuation and the seal should be removed completely. In this work, a method to utilize micro-machined silicon nitride membranes for this purpose is described. With an electric current, heaters on the membrane can induce thermal stress and break the sealing. A novel way to hold the splinters together with the help of a structured Parylene-C layer has been implemented. To fully expose the sensor area, bi-layered membranes have been investigated to exploit the self-roll-up effect caused by different intrinsic stress levels in the layers of the sealing membrane. Different variations of membrane composition have been fabricated and compared. To optimize the opening process, various designs for the metal electrodes have been designed, simulated and successfully tested.
{"title":"Optimization of the opening mechanism for micromachined sealings with a sacrificial multi-layer-membrane and thermoelectric actuation","authors":"Thomas Schweizer , Kapil Tagale , Henrik Nöbel , Andreas Schander , Michael J. Vellekoop","doi":"10.1016/j.sna.2025.117401","DOIUrl":"10.1016/j.sna.2025.117401","url":null,"abstract":"<div><div>Controlled opening of sealed microsensors is crucial for their correct functioning. Often, sensors need to be protected from the environment until they are deployed. This could be against humidity, harmful gases or biological contamination. Fragments of the sealing membrane are not wanted on the sensing element after actuation and the seal should be removed completely. In this work, a method to utilize micro-machined silicon nitride membranes for this purpose is described. With an electric current, heaters on the membrane can induce thermal stress and break the sealing. A novel way to hold the splinters together with the help of a structured Parylene-C layer has been implemented. To fully expose the sensor area, bi-layered membranes have been investigated to exploit the self-roll-up effect caused by different intrinsic stress levels in the layers of the sealing membrane. Different variations of membrane composition have been fabricated and compared. To optimize the opening process, various designs for the metal electrodes have been designed, simulated and successfully tested.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117401"},"PeriodicalIF":4.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study designed a novel high-efficiency air-coupled ultrasonic transducer based on a modified 1–3–2 piezoelectric composite with an epoxy/hollow glass microsphere filler system. Theoretical modeling was employed to investigate the effects of ceramic volume fraction under different substrate thicknesses on the acoustic performance of the 1–3–2 piezoelectric composite. The fabricated composite demonstrated measured parameters of 0.7 for electromechanical coupling factor and 14.05 MRayl for acoustic impedance, showing good agreement with theoretical predictions. Subsequently, a simulation model of the 1–3–2 air-coupled ultrasonic transducer was established based on the Leach model and transmission line theory. Comparative analysis revealed that the double-layer matching design enhanced the detection signal amplitude by approximately 123.2 % compared to single-layer matching, thereby determining the optimal matching layer parameters. Finally, the developed transducer exhibited superior defect detection capability in comparative tests with commercial Japanese probes.
{"title":"Design and fabrication of a new air-coupled ultrasonic transducer based on 1–3-2 piezoelectric composite filled with epoxy resin/hollow glass microsphere polymer","authors":"Jinjie Zhou , Ziliang Jia , Pengfei Zhou , Qiyun Liu","doi":"10.1016/j.sna.2025.117387","DOIUrl":"10.1016/j.sna.2025.117387","url":null,"abstract":"<div><div>This study designed a novel high-efficiency air-coupled ultrasonic transducer based on a modified 1–3–2 piezoelectric composite with an epoxy/hollow glass microsphere filler system. Theoretical modeling was employed to investigate the effects of ceramic volume fraction under different substrate thicknesses on the acoustic performance of the 1–3–2 piezoelectric composite. The fabricated composite demonstrated measured parameters of 0.7 for electromechanical coupling factor and 14.05 MRayl for acoustic impedance, showing good agreement with theoretical predictions. Subsequently, a simulation model of the 1–3–2 air-coupled ultrasonic transducer was established based on the Leach model and transmission line theory. Comparative analysis revealed that the double-layer matching design enhanced the detection signal amplitude by approximately 123.2 % compared to single-layer matching, thereby determining the optimal matching layer parameters. Finally, the developed transducer exhibited superior defect detection capability in comparative tests with commercial Japanese probes.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117387"},"PeriodicalIF":4.9,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-15DOI: 10.1016/j.sna.2025.117406
Ziyi An, Sihang Lv, Jiaqi Wang, Wendong Zhang, Lijiao Zu, Shi Qiu, Wa Jin, Xinghu Fu
A composite multi-parameter fiber sensor based on the Vernier effect was designed and fabricated for simultaneous axial strain and curvature measurement. The sensor integrates a Fabry-Perot interferometer (FPI) and a multimode interferometer (MMI), each constructed using hollow core fiber (HCF) with differing core diameters. The FPI uses an HCF with a larger core diameter, while the MMI is formed by cascading an HCF with a smaller core diameter to an HCF with a larger core diameter. Due to their distinct sensing mechanisms, the two interferometers respond differently, enabling simultaneous detection of axial strain and curvature. Experimental results indicate axial strain and curvature sensitivities of 2.94 pm/µε and 8.53 nm/m⁻¹ respectively, when the MMI is used as the sensing element. When the FPI is used as the sensing element, the strain sensitivity is enhanced to −4.38 pm/µɛ, and the curvature sensitivity is −5.61 nm/m⁻¹ . This sensor provides a novel tool for multi-dimensional parameter collection in intelligent control systems.
{"title":"Composite multi-parameter sensor based on hollow core fiber for measuring the axial strain and curvature","authors":"Ziyi An, Sihang Lv, Jiaqi Wang, Wendong Zhang, Lijiao Zu, Shi Qiu, Wa Jin, Xinghu Fu","doi":"10.1016/j.sna.2025.117406","DOIUrl":"10.1016/j.sna.2025.117406","url":null,"abstract":"<div><div>A composite multi-parameter fiber sensor based on the Vernier effect was designed and fabricated for simultaneous axial strain and curvature measurement. The sensor integrates a Fabry-Perot interferometer (FPI) and a multimode interferometer (MMI), each constructed using hollow core fiber (HCF) with differing core diameters. The FPI uses an HCF with a larger core diameter, while the MMI is formed by cascading an HCF with a smaller core diameter to an HCF with a larger core diameter. Due to their distinct sensing mechanisms, the two interferometers respond differently, enabling simultaneous detection of axial strain and curvature. Experimental results indicate axial strain and curvature sensitivities of 2.94 pm/µε and 8.53 nm/m⁻¹ respectively, when the MMI is used as the sensing element. When the FPI is used as the sensing element, the strain sensitivity is enhanced to −4.38 pm/µɛ, and the curvature sensitivity is −5.61 nm/m⁻¹ . This sensor provides a novel tool for multi-dimensional parameter collection in intelligent control systems.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117406"},"PeriodicalIF":4.9,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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