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Keywords = compact magnetic sensor

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8 pages, 2559 KiB  
Article
Dual-Layer Anomalous Hall Effect Sensor for Enhanced Accuracy and Range in Magnetic Field Detection
by Sitong An, Lvkang Shen, Tianyu Liu, Yan Wang, Qiuyang Han and Ming Liu
Nanomaterials 2025, 15(7), 527; https://doi.org/10.3390/nano15070527 - 31 Mar 2025
Viewed by 226
Abstract
This study introduces a method aimed at enhancing both the accuracy and the range of magnetic field sensors, which are two critical parameters, in a novel NiCo2O4-based anomalous Hall effect sensor. To fine-tune the linear range of the sensor, [...] Read more.
This study introduces a method aimed at enhancing both the accuracy and the range of magnetic field sensors, which are two critical parameters, in a novel NiCo2O4-based anomalous Hall effect sensor. To fine-tune the linear range of the sensor, we introduced epitaxial strain using a MgAl2O4 cover layer, which significantly influenced the strain-modulated magnetic anisotropy. A NiCo2O4/MgAl2O4/NiCo2O4/MgAl2O4 heterostructure was further constructed, achieving differentiation in the material characteristics across both upper and lower NiCo2O4 layers through the modulation of thickness and strain. A dual-layer Hall bar was designed to enhance the integration of the sensor, offering varied detection ranges. This approach enabled the realization of ultrahigh sensitivity, measuring 10,000 V/(AT) within a ±0.1 mT range, and a competitive sensitivity of 60 V/(AT) within a ±5 mT range. By reducing the thickness of the top NiCo2O4 layer, an ultra-wide measurement range of ±1000 mT was also achieved. These results highlight the considerable promise of NiCo2O4-based anomalous Hall effect devices as compact, multi-range tools in the domain of magnetic sensing technology. Full article
(This article belongs to the Special Issue Research on Ferroelectric and Spintronic Nanoscale Materials)
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22 pages, 5808 KiB  
Article
Surface Acoustic Wave Sensor for Selective Multi-Parameter Measurements in Cardiac Magnetic Field Detection
by Hongbo Zhao, Chunxiao Jiao, Qi Wang, Chao Gao and Jing Sun
Appl. Sci. 2025, 15(7), 3583; https://doi.org/10.3390/app15073583 - 25 Mar 2025
Cited by 1 | Viewed by 1622
Abstract
Measuring parameters like heart temperature, heart rate, and cardiac magnetic field aids in analyzing cardiac health and disease. A multi-parameter sensor tailored to the heart can significantly enhance convenience in medical diagnosis and treatment. This work introduces a multi-parameter sensor based on Surface [...] Read more.
Measuring parameters like heart temperature, heart rate, and cardiac magnetic field aids in analyzing cardiac health and disease. A multi-parameter sensor tailored to the heart can significantly enhance convenience in medical diagnosis and treatment. This work introduces a multi-parameter sensor based on Surface Acoustic Wave Sensors (SAWSs) and magnetostrictive materials, designed to selectively measure various cardiac parameters. SAWSs are characterized by their compact dimensions, which facilitate integration into various medical devices. The wireless and passive characteristics of the sensors enable flexibility in the detection process. This sensor can detect various common physical quantities like weak magnetic fields by the control variable method, ensuring a high degree of accuracy. The working mode of SAWSs is investigated in this study, and the relationship curve concerning various influencing factors is established. Full article
(This article belongs to the Section Nanotechnology and Applied Nanosciences)
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6 pages, 1042 KiB  
Proceeding Paper
Rapid Assessment of Canned Fish Quality via Fast Protein and Metabolite Liquid Chromatography
by Oksana V. Stepanova, Daniil Lyalin, Oksana S. Stepanova, Georgii Konoplev, Artur I. Kuznetsov, Liubov Abramova, Andrey Kozin and Aleksandr Frorip
Eng. Proc. 2024, 67(1), 85; https://doi.org/10.3390/engproc2024067085 - 10 Mar 2025
Viewed by 294
Abstract
The consumption of canned fish as an affordable and shelf-stable food product having high nutritional value is steadily growing in many parts of the world. An important and often overlooked factor that influences the quality of canned fish is the freshness of raw [...] Read more.
The consumption of canned fish as an affordable and shelf-stable food product having high nutritional value is steadily growing in many parts of the world. An important and often overlooked factor that influences the quality of canned fish is the freshness of raw materials used in the production process. It has been shown previously that the freshness status of fish can be assessed using fast proteins and metabolite liquid chromatography (FPMLC) detecting the relative content of post-mortem adenosine triphosphate (ATP) metabolites. The aim of this study is to evaluate the applicability of FPMLC to evaluate the quality of canned fish. Eighteen samples of various canned fish from different manufacturers were acquired from local supermarkets. FPMLC chromatograms of the samples were processed with the compact optoelectronic chromatographic sensor using PD-10 gel columns as a separation medium. The sensor has a photometric detector based on a deep UV LED emitting at 255–265 nm. All chromatograms showed two combined peaks: the first one was related to proteins and the second one was formed by adenosine ATP metabolites. The delay time between the peaks (the Time index) varied in a range from 138 s to 193 s. It was suggested that the higher the Time index, the fewer fresh raw fish materials were used for production. For additional verification of the FPMLC technique, four samples chosen as the most representative were analyzed by high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) spectroscopy. The Time index was in good correlation with the well-established nucleotide-based K and KI indices (quality factors) estimated from the HPLC chromatograms and NMR spectra, which confirms the fact that FPMLC can be used to assess the freshness of raw materials in thermally processed fish products. The correct interpretation of the Time index and other nucleotide-based indicators applied to canned food requires taking into account the effects of nutritional nucleotide thermal degradation that occur during high-temperature sterilization. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Processes)
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24 pages, 8269 KiB  
Article
Compact Multi-Channel Long-Wave Wideband Direction-Finding System and Direction-Finding Analysis for Different Modulation Signals
by Hangyu Lu, Shun Wang, Xin Xu, Yicai Ji and Xiaojun Liu
Appl. Sci. 2025, 15(5), 2570; https://doi.org/10.3390/app15052570 - 27 Feb 2025
Viewed by 351
Abstract
This paper presents an optimized long-wave (10–300 kHz) wideband direction-finding system for scientific research. The antenna unit of the system comprises one vertical electric field sensor and two horizontal magnetic field sensors oriented in the north–south and east–west directions, respectively. The overall design [...] Read more.
This paper presents an optimized long-wave (10–300 kHz) wideband direction-finding system for scientific research. The antenna unit of the system comprises one vertical electric field sensor and two horizontal magnetic field sensors oriented in the north–south and east–west directions, respectively. The overall design prioritizes compactness, engineering feasibility, and ease of deployment, enabling the effective reception of long-wave radio signals within the 10–300 kHz range. The magnetic field sensitivity reaches 8fT/Hz@, while the electric field sensitivity achieves 3.2μV/m/Hz@10kHz. The overall sensitivity of the receiver is 1μV (300 Hz bandwidth, 10 dB signal-to-noise ratio). The synchronization accuracy of the system is within 10 ns. Theoretically, with a baseline length of 5 km and a signal incidence angle ranging from 9.9° to 170.1°, the direction finding error is less than 2°. Additionally, direction-finding methods for MSK and ASK modulated signals are analyzed. To evaluate the system’s actual performance, initial measurements were conducted in Qingdao, Shandong. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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21 pages, 3464 KiB  
Article
Modeling of a Novel T-Core Sensor with an Air Gap for Applications in Eddy Current Nondestructive Evaluation
by Siquan Zhang
Sensors 2024, 24(24), 7931; https://doi.org/10.3390/s24247931 - 11 Dec 2024
Viewed by 736
Abstract
Multi-layer conductive structures, especially those with features like bolt holes, are vulnerable to hidden corrosion and cracking, posing a serious threat to equipment integrity. Early defect detection is vital for implementing effective maintenance strategies. However, the subtle signals produced by these defects necessitate [...] Read more.
Multi-layer conductive structures, especially those with features like bolt holes, are vulnerable to hidden corrosion and cracking, posing a serious threat to equipment integrity. Early defect detection is vital for implementing effective maintenance strategies. However, the subtle signals produced by these defects necessitate highly sensitive non-destructive testing (NDT) techniques. Analytical modeling plays a critical role in both enhancing defect-detection capabilities and guiding the design of highly sensitive sensors for these complex structures. Compared to the finite element method (FEM), analytical approaches offer advantages, such as faster computation and high accuracy, enabling a comprehensive analysis of how sensor and material parameters influence defect detection outcomes. This paper introduces a novel T-core eddy current sensor featuring a central air gap. Utilizing the vector magnetic potential method and a truncated region eigenfunction expansion (TREE) method, an analytical model was developed to investigate the sensor’s interaction with multi-layer conductive materials containing a hidden hole. The model yielded closed-form expressions for the induced eddy current density and coil impedance. A comparative study, implemented in Matlab, analyzed the eddy current distribution generated by T-core, E-core, I-core, and air core sensors under identical conditions. Furthermore, the study examined how the impedance of the T-core sensor changed at different excitation frequencies between 100 Hz and 10 kHz when positioned over a multi-layer conductor with a hidden air hole. These findings were then compared to those obtained from E-core, I-core, and air-core sensors. The analytical results were validated through finite element simulations and experimental measurements, exhibiting excellent agreement. The study further explored the influence of T-core design parameters, including the air gap radius, dome radius, core column height, and relative permeability of the T-core material, on the inspection sensitivity. Finally, the proposed T-core sensor was used to evaluate crack and hole defects in conductors, demonstrating its superior sensitivity compared to I-core and air core sensors. Although slightly less sensitive than the E-core sensor, the T-core sensor offers advantages, including a more compact design and reduced material requirements, making it well-suited for inspecting intricate and confined surfaces of the target object. This analytical model provides a valuable tool for designing advanced eddy current sensors, particularly for applications like detecting bolt hole defects or measuring the thickness of non-conductive coatings in multi-layer conductor structures. Full article
(This article belongs to the Topic Advances in Non-Destructive Testing Methods, 2nd Edition)
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59 pages, 20006 KiB  
Review
Magnetoelectric BAW and SAW Devices: A Review
by Bin Luo, Prasanth Velvaluri, Yisi Liu and Nian-Xiang Sun
Micromachines 2024, 15(12), 1471; https://doi.org/10.3390/mi15121471 - 3 Dec 2024
Cited by 2 | Viewed by 2168
Abstract
Magnetoelectric (ME) devices combining piezoelectric and magnetostrictive materials have emerged as powerful tools to miniaturize and enhance sensing and communication technologies. This paper examines recent developments in bulk acoustic wave (BAW) and surface acoustic wave (SAW) ME devices, which demonstrate unique capabilities in [...] Read more.
Magnetoelectric (ME) devices combining piezoelectric and magnetostrictive materials have emerged as powerful tools to miniaturize and enhance sensing and communication technologies. This paper examines recent developments in bulk acoustic wave (BAW) and surface acoustic wave (SAW) ME devices, which demonstrate unique capabilities in ultra-sensitive magnetic sensing, compact antennas, and quantum applications. Leveraging the mechanical resonance of BAW and SAW modes, ME sensors achieve the femto- to pico-Tesla sensitivity ideal for biomedical applications, while ME antennas, operating at acoustic resonance, allow significant size reduction, with high radiation gain and efficiency, which is suited for bandwidth-restricted applications. In addition, ME non-reciprocal magnetoacoustic devices using hybrid magnetoacoustic waves present novel solutions for RF isolation, which have also shown potential for the efficient control of quantum defects, such as negatively charged nitrogen-vacancy (NV) centers. Continued advancements in materials and device structures are expected to further enhance ME device performance, positioning them as key components in future bio-sensing, wireless communication, and quantum information technologies. Full article
(This article belongs to the Special Issue Novel Surface and Bulk Acoustic Wave Devices)
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19 pages, 22517 KiB  
Article
Development of a High-Precision Deep-Sea Magnetic Survey System for Human-Occupied Vehicles
by Qimao Zhang, Keyu Zhou, Ming Deng, Qisheng Zhang, Yongqiang Feng and Leisong Liu
Electronics 2024, 13(18), 3611; https://doi.org/10.3390/electronics13183611 - 11 Sep 2024
Viewed by 3748
Abstract
The high-precision magnetic survey system is crucial for ocean exploration. However, most existing systems face challenges such as high noise levels, low sensitivity, and inadequate magnetic compensation effects. To address these issues, we developed a high-precision magnetic survey system based on the manned [...] Read more.
The high-precision magnetic survey system is crucial for ocean exploration. However, most existing systems face challenges such as high noise levels, low sensitivity, and inadequate magnetic compensation effects. To address these issues, we developed a high-precision magnetic survey system based on the manned submersible “Deep Sea Warrior” for deep-ocean magnetic exploration. This system incorporates a compact optically pumped cesium (Cs) magnetometer sensor to measure the total strength of the external magnetic field. Additionally, a magnetic compensation sensor is included at the front end to measure real-time attitude changes of the platform. The measured data are then transmitted to a magnetic signal processor, where an algorithm compensates for the platform’s magnetic interference. We also designed a deep pressure chamber to allow for a maximum working depth of 4500 m. Experiments conducted in both indoor and field environments verified the performance of the proposed magnetic survey system. The results showed that the system’s sensitivity is ≤0.5 nT, the noise level of the magnetometer sensor is ≤1 pT/√Hz at 1 Hz, and the sampling rate is 10 Hz. The proposed system has potential applications in ocean and geophysical exploration. Full article
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12 pages, 3848 KiB  
Article
Current Measurement of Three-Core Cables via Magnetic Sensors
by Jingang Su, Peng Zhang, Xingwang Huang, Xianhai Pang, Xun Diao and Yan Li
Energies 2024, 17(16), 4007; https://doi.org/10.3390/en17164007 - 13 Aug 2024
Cited by 1 | Viewed by 997
Abstract
Due to their compact structure and low laying cost, three-core power cables are widely used for power distribution networks. The three-phases of such cables are distributed symmetrically with a 120° shift to each other. Phase current is an important parameter to reflect the [...] Read more.
Due to their compact structure and low laying cost, three-core power cables are widely used for power distribution networks. The three-phases of such cables are distributed symmetrically with a 120° shift to each other. Phase current is an important parameter to reflect the operation state of the power system and three-core cable. Three-core symmetrical power cables use a common shield, leading to magnetic field cancelation outside the cable during steady operation. Thus, traditional magnetic-based current transformers cannot measure the phase current on three-core cable non-invasively. In order to measure the phase current more conveniently, a phase current measurement method for three-core cables based on a magnetic sensor is proposed in this paper. Nonlinear equations of a phase current and the magnetic field of a measuring point are constructed. The calculated magnetic field distribution of the three-core cable is verified using a finite element simulation. The effectiveness of the measurement method is further validated through experiments. This proposed method is able to conveniently detect the phase current of three-core power cables, which can help cable maintenance. Full article
(This article belongs to the Special Issue Power Cables in Energy Systems)
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20 pages, 61036 KiB  
Article
3D Simulation-Driven Design of a Microfluidic Immunosensor for Real-Time Monitoring of Sweat Biomarkers
by Nessrine Jebari, Elisabeth Dufour-Gergam and Mehdi Ammar
Micromachines 2024, 15(8), 936; https://doi.org/10.3390/mi15080936 - 23 Jul 2024
Viewed by 5303
Abstract
This study presents the design and comprehensive 3D multiphysics simulation of a novel microfluidic immunosensor for non-invasive, real-time detection of pro-inflammatory biomarkers in human sweat. The patch-like device integrates magnetofluidic manipulation of antibody-functionalized magnetic nanoparticles (MNPs) with direct-field capacitive sensing (DF-CS). This unique [...] Read more.
This study presents the design and comprehensive 3D multiphysics simulation of a novel microfluidic immunosensor for non-invasive, real-time detection of pro-inflammatory biomarkers in human sweat. The patch-like device integrates magnetofluidic manipulation of antibody-functionalized magnetic nanoparticles (MNPs) with direct-field capacitive sensing (DF-CS). This unique combination enhances sensitivity, reduces parasitic capacitance, and enables a more compact design compared to traditional fringing-field approaches. A comprehensive 3D multiphysics simulation of the device, performed using COMSOL Multiphysics, demonstrates its operating principle by analyzing the sensor’s response to changes in the dielectric properties of the medium due to the presence of magnetic nanoparticles. The simulation reveals a sensitivity of 42.48% at 85% MNP occupancy within the detection zone, highlighting the sensor’s ability to detect variations in MNP concentration, and thus indirectly infer biomarker levels, with high precision. This innovative integration of magnetofluidic manipulation and DF-CS offers a promising new paradigm for continuous, non-invasive health monitoring, with potential applications in point-of-care diagnostics, personalized medicine, and preventive healthcare. Full article
(This article belongs to the Section B1: Biosensors)
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8 pages, 9556 KiB  
Proceeding Paper
Calibration-Free Current Measurement with Integrated Quantum Sensor
by Jens Pogorzelski, Ludwig Horsthemke, Jonas Homrighausen, Dennis Stiegekötter, Frederik Hoffmann, Ann-Sophie Bülter, Markus Gregor and Peter Glösekötter
Eng. Proc. 2024, 68(1), 58; https://doi.org/10.3390/engproc2024068058 - 22 Jul 2024
Viewed by 1319
Abstract
This paper presents the application of a compact and fully integrated LED quantum sensor based on the NV centers in diamond for current measurement in a busbar. The magnetic field measurements from the sensor are directly compared with measurements from a numerical simulation, [...] Read more.
This paper presents the application of a compact and fully integrated LED quantum sensor based on the NV centers in diamond for current measurement in a busbar. The magnetic field measurements from the sensor are directly compared with measurements from a numerical simulation, eliminating the need for calibration. The sensor setup achieves an accuracy of 0.28% in the measurement range of 0–30 A DC. The integration of advanced quantum sensing technology with practical current measurement demonstrates the potential of this sensor for applications in electrical and distribution networks. Full article
(This article belongs to the Proceedings of The 10th International Conference on Time Series and Forecasting)
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15 pages, 4124 KiB  
Article
IoT-Based Heartbeat Rate-Monitoring Device Powered by Harvested Kinetic Energy
by Olivier Djakou Nekui, Wei Wang, Cheng Liu, Zhixia Wang and Bei Ding
Sensors 2024, 24(13), 4249; https://doi.org/10.3390/s24134249 - 29 Jun 2024
Cited by 1 | Viewed by 2714
Abstract
Remote patient-monitoring systems are helpful since they can provide timely and effective healthcare facilities. Such online telemedicine is usually achieved with the help of sophisticated and advanced wearable sensor technologies. The modern type of wearable connected devices enable the monitoring of vital sign [...] Read more.
Remote patient-monitoring systems are helpful since they can provide timely and effective healthcare facilities. Such online telemedicine is usually achieved with the help of sophisticated and advanced wearable sensor technologies. The modern type of wearable connected devices enable the monitoring of vital sign parameters such as: heart rate variability (HRV) also known as electrocardiogram (ECG), blood pressure (BLP), Respiratory rate and body temperature, blood pressure (BLP), respiratory rate, and body temperature. The ubiquitous problem of wearable devices is their power demand for signal transmission; such devices require frequent battery charging, which causes serious limitations to the continuous monitoring of vital data. To overcome this, the current study provides a primary report on collecting kinetic energy from daily human activities for monitoring vital human signs. The harvested energy is used to sustain the battery autonomy of wearable devices, which allows for a longer monitoring time of vital data. This study proposes a novel type of stress- or exercise-monitoring ECG device based on a microcontroller (PIC18F4550) and a Wi-Fi device (ESP8266), which is cost-effective and enables real-time monitoring of heart rate in the cloud during normal daily activities. In order to achieve both portability and maximum power, the harvester has a small structure and low friction. Neodymium magnets were chosen for their high magnetic strength, versatility, and compact size. Due to the non-linear magnetic force interaction of the magnets, the non-linear part of the dynamic equation has an inverse quadratic form. Electromechanical damping is considered in this study, and the quadratic non-linearity is approximated using MacLaurin expansion, which enables us to find the law of motion for general case studies using classical methods for dynamic equations and the suitable parameters for the harvester. The oscillations are enabled by applying an initial force, and there is a loss of energy due to the electromechanical damping. A typical numerical application is computed with Matlab 2015 software, and an ODE45 solver is used to verify the accuracy of the method. Full article
(This article belongs to the Section Wearables)
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10 pages, 355 KiB  
Article
Low-Power Magnetic Displacement Sensor Based on RISC-V Embedded System
by Tao Sun, Yue Song and Huiyun Yang
Sensors 2024, 24(13), 4224; https://doi.org/10.3390/s24134224 - 29 Jun 2024
Viewed by 1224
Abstract
With the emergence of RISC-V architecture in embedded devices, its inherent low-power features have propelled its extensive adoption across various industrial settings. Displacement sensors leveraging Hall sensors and magnetic flux measurement present notable benefits including cost-effectiveness and compact design. This study undertakes the [...] Read more.
With the emergence of RISC-V architecture in embedded devices, its inherent low-power features have propelled its extensive adoption across various industrial settings. Displacement sensors leveraging Hall sensors and magnetic flux measurement present notable benefits including cost-effectiveness and compact design. This study undertakes the porting of Hall sensors onto RISC-V architecture embedded devices, validating their functionality within displacement sensors. Empirical investigations substantiate that the ported system consistently delivers comparable outcomes to those obtained from x86 architecture systems employing PM-MFM methods, affirming its reliability and performance in practical applications. Full article
(This article belongs to the Section Electronic Sensors)
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16 pages, 11154 KiB  
Article
Design of Fluxgate Current Sensor Based on Magnetization Residence Times and Neural Networks
by Jingjie Li, Wei Ren, Yanshou Luo, Xutong Zhang, Xinpeng Liu and Xue Zhang
Sensors 2024, 24(12), 3752; https://doi.org/10.3390/s24123752 - 9 Jun 2024
Cited by 4 | Viewed by 1765
Abstract
This study introduces a novel fluxgate current sensor with a compact, ring-shaped configuration that exhibits improved performance through the integration of magnetization residence times and neural networks. The sensor distinguishes itself with a unique magnetization profile, denoted as M waves, which emerge from [...] Read more.
This study introduces a novel fluxgate current sensor with a compact, ring-shaped configuration that exhibits improved performance through the integration of magnetization residence times and neural networks. The sensor distinguishes itself with a unique magnetization profile, denoted as M waves, which emerge from the interaction between the target signal and ambient magnetic interference, effectively enhancing interference suppression. These M waves highlight the non-linear coupling between the magnetic field and magnetization residence times. Detection of these residence times is accomplished using full-wave rectification circuits and a Schmitt trigger, with a digital output provided by timing sequence detection. A dual-layer feedforward neural network deciphers the target signal, exploiting this non-linear relationship. The sensor achieves a linearity error of 0.054% within a measurement range of 15 A. When juxtaposed with conventional sensors utilizing the residence-time difference strategy, our sensor reduces linearity error by more than 40-fold and extends the effective measurement range by 150%. Furthermore, it demonstrates a significant decrease in ambient magnetic interference. Full article
(This article belongs to the Special Issue Dalian University of Technology Celebrating 75th Anniversary)
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23 pages, 4710 KiB  
Article
Evaluation of Pipe Thickness by Magnetic Hammer Test with a Tunnel Magnetoresistive Sensor
by Jun Ito, Yudai Igarashi, Ryota Odagiri, Shigetaka Suzuki, Hiroshi Wagatsuma, Kazuhiro Sugiyama and Mikihiko Oogane
Sensors 2024, 24(5), 1620; https://doi.org/10.3390/s24051620 - 1 Mar 2024
Cited by 1 | Viewed by 2856
Abstract
A new nondestructive inspection method, the magnetic hammer test (MHT), which uses a compact and highly sensitive tunnel magnetoresistance (TMR) sensor, is proposed. This method complements the magnetic flux leakage method and eliminates the issues of the hammer test. It can therefore detect [...] Read more.
A new nondestructive inspection method, the magnetic hammer test (MHT), which uses a compact and highly sensitive tunnel magnetoresistance (TMR) sensor, is proposed. This method complements the magnetic flux leakage method and eliminates the issues of the hammer test. It can therefore detect weak magnetic fields generated by the natural vibration of a pipe with a high signal-to-noise ratio. In this study, several steel pipes with different wall thicknesses were measured using a TMR sensor to demonstrate the superiority of MHT. The results of the measurement show that wall thickness can be evaluated with the accuracy of several tens of microns from the change in the natural vibration frequency of the specimen pipe. The pipes were also inspected underwater using a waterproofed TMR sensor, which demonstrated an accuracy of less than 100 μm. The validity of these results was by simulating the shielding of magnetic fields and vibration of the pipes with the finite element method (FEM) analysis. The proposed noncontact, fast, and accurate method for thickness testing of long-distance pipes will contribute to unmanned, manpower-saving nondestructive testing (NDT) in the future. Full article
(This article belongs to the Special Issue Non-destructive Inspection with Sensors)
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24 pages, 7233 KiB  
Article
Improving Indoor Pedestrian Dead Reckoning for Smartphones under Magnetic Interference Using Deep Learning
by Ping Zhu, Xuexiang Yu, Yuchen Han, Xingxing Xiao and Yu Liu
Sensors 2023, 23(23), 9348; https://doi.org/10.3390/s23239348 - 23 Nov 2023
Cited by 5 | Viewed by 2406
Abstract
As micro-electro-mechanical systems (MEMS) technology continues its rapid ascent, a growing array of smart devices are integrating lightweight, compact, and cost-efficient magnetometers and inertial sensors, paving the way for advanced human motion analysis. However, sensors housed within smartphones frequently grapple with the detrimental [...] Read more.
As micro-electro-mechanical systems (MEMS) technology continues its rapid ascent, a growing array of smart devices are integrating lightweight, compact, and cost-efficient magnetometers and inertial sensors, paving the way for advanced human motion analysis. However, sensors housed within smartphones frequently grapple with the detrimental effects of magnetic interference on heading estimation, resulting in diminished accuracy. To counteract this challenge, this study introduces a method that synergistically employs convolutional neural networks (CNNs) and support vector machines (SVMs) for adept interference detection. Utilizing a CNN, we automatically extract profound features from single-step pedestrian motion data that are then channeled into an SVM for interference detection. Based on these insights, we formulate heading estimation strategies aptly suited for scenarios both devoid of and subjected to magnetic interference. Empirical assessments underscore our method’s prowess, boasting an impressive interference detection accuracy of 99.38%. In indoor environments influenced by such magnetic disturbances, evaluations conducted along square and equilateral triangle trajectories revealed single-step heading absolute error averages of 2.1891° and 1.5805°, with positioning errors averaging 0.7565 m and 0.3856 m, respectively. These results lucidly attest to the robustness of our proposed approach in enhancing indoor pedestrian positioning accuracy in the face of magnetic interferences. Full article
(This article belongs to the Section Navigation and Positioning)
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