Pub Date : 2025-12-22DOI: 10.1016/j.sna.2025.117420
Tianrun Wang , Tangzhen Guan , Zinan Guo , Changle Miao , Xingfu Wan , Hao Jin , Yuanzheng Li , Xiaotong Gu , Jianhua Liu , Peng Xu
Underwater sensing technologies face significant challenges due to environmental noise, water turbidity, and multipath interference that can hinder reliable data acquisition. To overcome these limitations, we present a novel Liquid Metal-Based Whisker Sensor (LMWS), whose design is inspired by the vibrissae of sea lions. The sensor incorporates a liquid metal-embedded elastomer (LMEE) that acts as an advanced triboelectric material. This design offers outstanding flexibility, intrinsic self-healing properties, and reliable performance under extreme conditions, including subzero temperatures (-7°C) and high hydrostatic pressures (up to 3 MPa at 300 m depth). Our experimental evaluations demonstrate an electrical self-repair efficiency of 88.7 %, a sensitivity of 0.25 V/mm, and a signal-to-noise ratio of 19.6 dB. In addition to mimicking biological detection mechanisms, the LMWS provides a robust solution for improving underwater sensing capabilities. Its integration into remotely operated vehicles (ROVs) shows promise for enhanced navigation and obstacle detection in challenging deep-sea environments, paving the way for future developments in marine exploration and environmental monitoring. These advances represent a significant leap in underwater sensor technology.
{"title":"Liquid metal-based whisker sensor with self-healing interfaces for underwater instantaneous contact localization","authors":"Tianrun Wang , Tangzhen Guan , Zinan Guo , Changle Miao , Xingfu Wan , Hao Jin , Yuanzheng Li , Xiaotong Gu , Jianhua Liu , Peng Xu","doi":"10.1016/j.sna.2025.117420","DOIUrl":"10.1016/j.sna.2025.117420","url":null,"abstract":"<div><div>Underwater sensing technologies face significant challenges due to environmental noise, water turbidity, and multipath interference that can hinder reliable data acquisition. To overcome these limitations, we present a novel Liquid Metal-Based Whisker Sensor (LMWS), whose design is inspired by the vibrissae of sea lions. The sensor incorporates a liquid metal-embedded elastomer (LMEE) that acts as an advanced triboelectric material. This design offers outstanding flexibility, intrinsic self-healing properties, and reliable performance under extreme conditions, including subzero temperatures (-7°C) and high hydrostatic pressures (up to 3 MPa at 300 m depth). Our experimental evaluations demonstrate an electrical self-repair efficiency of 88.7 %, a sensitivity of 0.25 V/mm, and a signal-to-noise ratio of 19.6 dB. In addition to mimicking biological detection mechanisms, the LMWS provides a robust solution for improving underwater sensing capabilities. Its integration into remotely operated vehicles (ROVs) shows promise for enhanced navigation and obstacle detection in challenging deep-sea environments, paving the way for future developments in marine exploration and environmental monitoring. These advances represent a significant leap in underwater sensor technology.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117420"},"PeriodicalIF":4.9,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841338","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 : 2025-12-19DOI: 10.1016/j.sna.2025.117415
Komal Kukreja , Shewli Pratihar , Prasanta K. Panda , Prasanna Kumar S Mural
With advancements in science and nanotechnology, smart wearables have emerged as a promising research area due to their ability to harvest energy by converting waste mechanical energy into electrical energy using nanogenerators. These devices find applications in sensors, batteries, supercapacitors, and electronic textiles. Smart wearables can be fabricated using piezoelectric polymers, among which polyvinylidene fluoride (PVDF) is widely recognized for its electroactive β-phase, responsible for generating voltage potential in the presence of an external electric field. In this work, PVDF-based piezoelectric nanogenerators comprised with Molybdenum Aluminum Carbide (Mo₃AlC₂) are fabricated. Molybdenum Aluminum Carbide (Mo₃AlC₂), a two-dimensional (2D) ternary carbide and nitride, has a distinct set of ceramic and metallic characteristics. Pure PVDF and composites were then characterized to compare their structural, thermal, and electrical properties, such as dielectric, ferroelectric, and piezoelectric behaviors. Among the prepared samples, the PVDF composite with 5 wt% Mo₃AlC₂ particles (5 % PMAC) exhibited the best performance for energy harvesting. The 5 % PMAC composite showed a piezoelectric coefficient (d₃₃) of about 23 pm/V and a polar phase fraction of 76.4 %, whereas the pure PVDF showed a d₃₃ value of about 12 pm/V and a polar phase fraction of 66.8 %. Under a 25 N periodic mechanical force at a frequency of 15 Hz, the 5 % PMAC-based composite generated a peak voltage and current of 13.8 V and 1.2 µA, respectively, whereas the pure PVDF film generated 4.84 V and 0.7 µA under the same applied force. The 5 % PMAC composite with the optimal percent attained the highest power output of 1.76 µW and successfully powered capacitors, lit up LEDs, and facilitated real-time monitoring of human motion. These results demonstrate the promise of PVDF/Mo₃AlC₂ composites for a variety of applications, such as harvesting human motion energy and energizing low-energy electronic devices.
{"title":"High-performance piezoelectric nanogenerator based on PVDF/2D layered Mo₃AlC₂ composites for sustainable energy harvesting applications","authors":"Komal Kukreja , Shewli Pratihar , Prasanta K. Panda , Prasanna Kumar S Mural","doi":"10.1016/j.sna.2025.117415","DOIUrl":"10.1016/j.sna.2025.117415","url":null,"abstract":"<div><div>With advancements in science and nanotechnology, smart wearables have emerged as a promising research area due to their ability to harvest energy by converting waste mechanical energy into electrical energy using nanogenerators. These devices find applications in sensors, batteries, supercapacitors, and electronic textiles. Smart wearables can be fabricated using piezoelectric polymers, among which polyvinylidene fluoride (PVDF) is widely recognized for its electroactive β-phase, responsible for generating voltage potential in the presence of an external electric field. In this work, PVDF-based piezoelectric nanogenerators comprised with Molybdenum Aluminum Carbide (Mo₃AlC₂) are fabricated. Molybdenum Aluminum Carbide (Mo₃AlC₂), a two-dimensional (2D) ternary carbide and nitride, has a distinct set of ceramic and metallic characteristics. Pure PVDF and composites were then characterized to compare their structural, thermal, and electrical properties, such as dielectric, ferroelectric, and piezoelectric behaviors. Among the prepared samples, the PVDF composite with 5 wt% Mo₃AlC₂ particles (5 % PMAC) exhibited the best performance for energy harvesting. The 5 % PMAC composite showed a piezoelectric coefficient (d₃₃) of about 23 pm/V and a polar phase fraction of 76.4 %, whereas the pure PVDF showed a d₃₃ value of about 12 pm/V and a polar phase fraction of 66.8 %. Under a 25 N periodic mechanical force at a frequency of 15 Hz, the 5 % PMAC-based composite generated a peak voltage and current of 13.8 V and 1.2 µA, respectively, whereas the pure PVDF film generated 4.84 V and 0.7 µA under the same applied force. The 5 % PMAC composite with the optimal percent attained the highest power output of 1.76 µW and successfully powered capacitors, lit up LEDs, and facilitated real-time monitoring of human motion. These results demonstrate the promise of PVDF/Mo₃AlC₂ composites for a variety of applications, such as harvesting human motion energy and energizing low-energy electronic devices.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117415"},"PeriodicalIF":4.9,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841293","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 : 2025-12-19DOI: 10.1016/j.sna.2025.117416
Abhishek Anand Ukey, C.V. Krishnamurthy, V. Subramanian
A wideband microwave bolometer array is presented that employs an in-house developed microwave absorber with a commercial thermistor as the sensing element. The array generates a temperature map by absorbing the incident microwave energy, enabling the determination of spatial energy distribution by scanning the incident microwave field. Material synthesis and characteristics of the microwave absorber are described. The characteristics of the thermistor, the construction of the sensor array system, and the resistance-temperature mapping are presented. The microwave responsivity and noise of the composite sensor pixels are evaluated for a frequency range of 8–40 GHz. The performance of the array is demonstrated by mapping the unperturbed and perturbed spatial energy distributions across a waveguide aperture that operates in the TE10 mode at a low input power of 10 mW, exhibiting strong agreement with simulations. The proposed array offers a passive solution for characterizing complex microwave fields.
{"title":"Development of wideband bolometer based on polymer nanocomposite for microwave field-distribution mapping","authors":"Abhishek Anand Ukey, C.V. Krishnamurthy, V. Subramanian","doi":"10.1016/j.sna.2025.117416","DOIUrl":"10.1016/j.sna.2025.117416","url":null,"abstract":"<div><div>A wideband microwave bolometer array is presented that employs an in-house developed microwave absorber with a commercial thermistor as the sensing element. The array generates a temperature map by absorbing the incident microwave energy, enabling the determination of spatial energy distribution by scanning the incident microwave field. Material synthesis and characteristics of the microwave absorber are described. The characteristics of the thermistor, the construction of the sensor array system, and the resistance-temperature mapping are presented. The microwave responsivity and noise of the composite sensor pixels are evaluated for a frequency range of 8–40 GHz. The performance of the array is demonstrated by mapping the unperturbed and perturbed spatial energy distributions across a waveguide aperture that operates in the TE<sub>10</sub> mode at a low input power of 10 mW, exhibiting strong agreement with simulations. The proposed array offers a passive solution for characterizing complex microwave fields.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117416"},"PeriodicalIF":4.9,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841336","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.2025.117410
Mingzhe Zhang , Quanwang Niu , Xiyuan Chen , Xiaohong Yan , Xiangfu Wang
All-optical logic gates eliminate the signal loss associated with electro–optical conversion and provide an effective pathway toward high-speed and low-power information processing. In this work, we design all-optical logic gates based on the photoluminescence response of Eu3 + -doped Na0.5Gd1.5SbTiO7. The switching states of 257 nm and 275 nm light sources with fixed luminous intensities are used as logic gate inputs. The gate outputs are defined by the ratios of red (R) and orange (O) emission intensities relative to the excitation light and their R/O intensity ratios. By setting suitable intensity thresholds, basic logic functions such as “AND” and “OR” gates can be realized. Building on this, temperature and doping concentration are incorporated as additional input variables. Through the combination of threshold settings and the observed changes in luminescence, more complex logic functions including “XNOR”, “OR”, and “AND” gates are realized. Furthermore, by integrating the designed “XNOR” and “AND” logic gates, the functions of a half-adder and half-subtractor are successfully demonstrated, based on the principles of digital logic computation. This work illustrates the application potential of Eu3+ ion-doped composite oxide photoluminescent materials in the fundamental modules of optical computing and offers novel insights into achieving functional integration and stable performance in high-efficiency optical logic devices.
{"title":"Design of all-optical logic gates based on Eu³⁺-doped rare-earth luminescent materials","authors":"Mingzhe Zhang , Quanwang Niu , Xiyuan Chen , Xiaohong Yan , Xiangfu Wang","doi":"10.1016/j.sna.2025.117410","DOIUrl":"10.1016/j.sna.2025.117410","url":null,"abstract":"<div><div>All-optical logic gates eliminate the signal loss associated with electro–optical conversion and provide an effective pathway toward high-speed and low-power information processing. In this work, we design all-optical logic gates based on the photoluminescence response of Eu<sup>3 +</sup> -doped Na<sub>0.5</sub>Gd<sub>1.5</sub>SbTiO<sub>7</sub>. The switching states of 257 nm and 275 nm light sources with fixed luminous intensities are used as logic gate inputs. The gate outputs are defined by the ratios of red (R) and orange (O) emission intensities relative to the excitation light and their R/O intensity ratios. By setting suitable intensity thresholds, basic logic functions such as “AND” and “OR” gates can be realized. Building on this, temperature and doping concentration are incorporated as additional input variables. Through the combination of threshold settings and the observed changes in luminescence, more complex logic functions including “XNOR”, “OR”, and “AND” gates are realized. Furthermore, by integrating the designed “XNOR” and “AND” logic gates, the functions of a half-adder and half-subtractor are successfully demonstrated, based on the principles of digital logic computation. This work illustrates the application potential of Eu<sup>3+</sup> ion-doped composite oxide photoluminescent materials in the fundamental modules of optical computing and offers novel insights into achieving functional integration and stable performance in high-efficiency optical logic devices.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117410"},"PeriodicalIF":4.9,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791692","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.2025.117391
Furkan Peker , Ö. Gökalp Akcan , Dila Atak , Ibrahim H. Ozata , Derya S. Uymaz , Emre Balik , Müjdat Zeybel , Hamdi Torun , Onur Ferhanoğlu
The correlation between tissue elasticity and histopathological diagnosis has brought attention to the development of biomedical devices for in-vivo measurement of tissue biomechanical properties. Towards this aim, we have developed a tactile sensing capsule endoscope to measure tissue Young’s modulus, in situ. Inspired by force microscopy, the capsule comprises four cantilevers that probe the walls of the GI tract using a single miniaturized actuator. The force exerted on the cantilever tip by the tissue is measured using the piezoelectric layer integrated on the cantilevers. The tactile-based modulus sensing capsule was initially tested on ex-vivo animal tissue, followed by healthy and cancerous human specimens. The results clearly delineate the differences in mechanical properties, with a Young’s modulus of 11.3 2.3 kPa for healthy and 26.8 4.6 kPa for cancerous tissue. Overall, in the realm of tactile-based modulus sensing of tissues, our technology uniquely combines localized, quantitative Young’s modulus measurements with the capability to perform multiple measurements throughout the GI tract wall in a single procedure. Moreover, the developed sensor has a compact form factor, in accordance with the capsule dimensions, and simple manufacturing steps using stereolithography. With further improvements, the developed medical device can be utilized as a non-invasive diagnostic tool in the clinic.
{"title":"A tactile sensing capsule endoscope employing force sensing cantilevers for tumor diagnosis in the GI tract","authors":"Furkan Peker , Ö. Gökalp Akcan , Dila Atak , Ibrahim H. Ozata , Derya S. Uymaz , Emre Balik , Müjdat Zeybel , Hamdi Torun , Onur Ferhanoğlu","doi":"10.1016/j.sna.2025.117391","DOIUrl":"10.1016/j.sna.2025.117391","url":null,"abstract":"<div><div>The correlation between tissue elasticity and histopathological diagnosis has brought attention to the development of biomedical devices for <em>in-vivo</em> measurement of tissue biomechanical properties. Towards this aim, we have developed a tactile sensing capsule endoscope to measure tissue Young’s modulus, in situ. Inspired by force microscopy, the capsule comprises four cantilevers that probe the walls of the GI tract using a single miniaturized actuator. The force exerted on the cantilever tip by the tissue is measured using the piezoelectric layer integrated on the cantilevers. The tactile-based modulus sensing capsule was initially tested on <em>ex-vivo</em> animal tissue, followed by healthy and cancerous human specimens. The results clearly delineate the differences in mechanical properties, with a Young’s modulus of 11.3 <span><math><mo>±</mo></math></span> 2.3 kPa for healthy and 26.8 <span><math><mo>±</mo></math></span> 4.6 kPa for cancerous tissue. Overall, in the realm of tactile-based modulus sensing of tissues, our technology uniquely combines localized, quantitative Young’s modulus measurements with the capability to perform multiple measurements throughout the GI tract wall in a single procedure. Moreover, the developed sensor has a compact form factor, in accordance with the capsule dimensions, and simple manufacturing steps using stereolithography. With further improvements, the developed medical device can be utilized as a non-invasive diagnostic tool in the clinic.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117391"},"PeriodicalIF":4.9,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841343","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.2025.117403
Jiajia Shi , Yun Peng , Conghai Ge , Guangyu Song , Yong Zhao , IEEE Member
A tunable dispersion turning point (DTP) microfiber sensor was fabricated through a three-step process involving discharge-melting, fiber tapering, and hydrofluoric acid (HF) etching. The DTP was finely adjusted by controlling both the refractive index (RI) of the etching solution and the etching duration, enabling optimization for biomarker detection. The sensor exhibited a high RI sensitivity of up to 21652 nm/RIU. Experimental results for alpha-fetoprotein (AFP) detection indicated that the DTP biosensor has a linear concentration range from 1 × 10−9 μg/mL to 1 × 10−2 μg/mL (R2 = 0.996), with an AFP detection sensitivity of 2.039 nm/log(μg/mL). The limit of detection (LOD) for AFP in phosphate-buffered saline (PBS) was determined to be 3.04 × 10−10 μg/mL. Owing to its high sensitivity, low LOD, broad linear detection range, minimal temperature interference, and compatibility with in situ detection, the sensor demonstrates strong potential for trace-level AFP analysis. This platform offers a cost-effective and highly sensitive approach for early-stage liver cancer diagnosis and disease monitoring, thereby contributing to the broader implementation of early cancer screening strategies.
{"title":"High sensitivity and low temperature crosstalk alpha-fetoprotein detection using tunable dispersion turning point microfiber through optimized hydrofluoric acid etching process","authors":"Jiajia Shi , Yun Peng , Conghai Ge , Guangyu Song , Yong Zhao , IEEE Member","doi":"10.1016/j.sna.2025.117403","DOIUrl":"10.1016/j.sna.2025.117403","url":null,"abstract":"<div><div>A tunable dispersion turning point (DTP) microfiber sensor was fabricated through a three-step process involving discharge-melting, fiber tapering, and hydrofluoric acid (HF) etching. The DTP was finely adjusted by controlling both the refractive index (RI) of the etching solution and the etching duration, enabling optimization for biomarker detection. The sensor exhibited a high RI sensitivity of up to 21652 nm/RIU. Experimental results for alpha-fetoprotein (AFP) detection indicated that the DTP biosensor has a linear concentration range from 1 × 10<sup>−9</sup> μg/mL to 1 × 10<sup>−2</sup> μg/mL (R<sup>2</sup> = 0.996), with an AFP detection sensitivity of 2.039 nm/log(μg/mL). The limit of detection (LOD) for AFP in phosphate-buffered saline (PBS) was determined to be 3.04 × 10<sup>−10</sup> μg/mL. Owing to its high sensitivity, low LOD, broad linear detection range, minimal temperature interference, and compatibility with in situ detection, the sensor demonstrates strong potential for trace-level AFP analysis. This platform offers a cost-effective and highly sensitive approach for early-stage liver cancer diagnosis and disease monitoring, thereby contributing to the broader implementation of early cancer screening strategies.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117403"},"PeriodicalIF":4.9,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791676","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.2025.117413
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}
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