scholarly journals Rotating Focused Field Eddy-Current Sensing for Arbitrary Orientation Defects Detection in Carbon Steel

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2345 ◽  
Author(s):  
Zhiyuan Xu ◽  
Xiang Wang ◽  
Yiming Deng
Keyword(s):  
Magnetic Field ◽  
Carbon Steel ◽  
Eddy Current ◽  
Signal To Noise Ratio ◽  
Signal Amplitude ◽  
Element Model ◽  
Rotating Magnetic Field ◽  
Design Parameters ◽  
Arbitrary Orientation ◽  
Focusing Effect

This paper presents a rotating focused field eddy-current (EC) sensing technique, which leverages the advantages of magnetic field focusing and rotating magnetic field, for arbitrary orientation defects detection. The sensor consists of four identical excitation coils orthogonally arranged in an upside-down pyramid configuration and a giant magneto-resistive (GMR) detection element. The four coils are connected to form two figure-8-shaped focusing sub-probes, which are fed by two identical harmonic currents with 90 degrees phase difference. A finite element model-based study of arbitrary orientation defects detection was performed to understand the probe operational characteristics and optimize its design parameters. Probe prototyping and experimental validation were also carried out on a carbon steel plate specimen with four prefabricated surface-breaking defects. In-situ spot inspection with the probe rotating above the defect and a manual line-scan inspection were both conducted. Results showed that the probe has the capability of detecting defects with any orientations while maintaining the same sensitivity and the defect depth can be quantitatively evaluated by using the signal amplitude. Compared with the existing rotating field probes, the presented probe does not require additional excitation adjustment or data fusion. Meanwhile, due to its focusing effect, it can generate a strong rotating magnetic field at the defect location with a weak background noise, thus yielding superior signal-to-noise ratio.

Eddy Current Loss and Shielding Research of the Tank in Power Transformer

2012 ◽  
Vol 468-471 ◽  
pp. 1086-1089 ◽  
Author(s):  
Yong Ming Xu ◽  
Chao Du ◽  
Da Wei Meng
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Power Transformer ◽  
Element Model ◽  
Eddy Current Loss ◽  
Calculation Model ◽  
Ultrahigh Pressure ◽  
Tank Wall ◽  
Current Loss ◽  
Leakage Magnetic Field

The problem about the eddy current loss which is caused by leakage magnetic field in ultrahigh pressure large capacity power transformer is becoming more extrusive. It is very significant to research the power transformer leakage magnetic field and eddy current loss on the tank wall thoroughly and accurately. 3D finite element model of power transformer leakage magnetic field and eddy current loss is established in this paper, the eddy current loss on the tank wall is calculated and the distribution is analyzed. For the eddy current loss could be reduced by magnetic shielding, new calculation model are established respectively, then eddy current loss on tank wall could be got with shielding. The best size and location of the shielding could be analyzed after changing the height of the shielding, which provided the important evidence to reduce tank wall eddy current loss effectively. The calculating methods have been proved to be accuracy after experiment.

scholarly journals Design and Parameter Research of Time-Harmonic Magnetic Field Sensor Based on PDMS in Microfluidic Technology

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2022
Author(s):  
Chenzhao Bai ◽  
Hongpeng Zhang ◽  
Chengjie Wang ◽  
Lebile Ilerioluwa Joseph ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Throughput ◽  
Signal To Noise Ratio ◽  
Control Variable ◽  
Abrasive Particle ◽  
Design Parameters ◽  
Detection Accuracy ◽  
Particle Detection ◽  
Detection Technology ◽  
Time Harmonic

In order to improve the throughput and sensitivity of the inductive metal micro-abrasive particle detection sensor, this paper uses microfluidic detection technology to design a high-throughput abrasive particle detection sensor based on PDMS (Polydimethylsiloxane). Theoretical modeling analyzes the magnetization of metal abrasive particles in the coil’s time-harmonic magnetic field, and uses COMSOL simulation to calculate the best performance parameters of the sensor. Through the experiment of the control variable method, the corresponding signal value is obtained and the signal-to-noise ratio (SNR) is calculated. The SNR value and error value are calculated, and the SNR is corrected. The detection limit of the sensor is determined to be 10 μm iron particles and 60 μm copper particles. The optimal design parameters of the 3-D solenoid coil and the frequency characteristics of the sensor are obtained. Finally, through high-throughput experiments and analysis, it was found that there was a reasonable error between the actual throughput and the theoretical throughput. The design ideas suggested in this article can not only improve the sample throughput, but also ensure the detection accuracy. This provides a new idea for the development of an inductive on-line detection method of abrasive particle technology.

scholarly journals Magnetic Nanomotor-Based Maneuverable SERS Probe

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yong Wang ◽  
Yuhuan Liu ◽  
Yang Li ◽  
Dandan Xu ◽  
Xi Pan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Signal To Noise Ratio ◽  
Surface Enhanced Raman Spectroscopy ◽  
The Self ◽  
Rotating Magnetic Field ◽  
Small Scale ◽  
Biochemical Sensing ◽  
Surface Enhanced Raman ◽  
Single Use ◽  
Sers Sensing

Surface-enhanced Raman spectroscopy (SERS) is a powerful sensing technique capable of capturing ultrasensitive fingerprint signal of analytes with extremely low concentration. However, conventional SERS probes are passive nanoparticles which are usually massively applied for biochemical sensing, lacking controllability and adaptability for precise and targeted sensing at a small scale. Herein, we report a “rod-like” magnetic nanomotor-based SERS probe (MNM-SP) that integrates a mobile and controllable platform of micro-/nanomotors with a SERS sensing technique. The “rod-like” structure is prepared by coating a thin layer of silica onto the self-assembled magnetic nanoparticles. Afterwards, SERS hotspots of silver nanoparticles (AgNPs) are decorated as detecting nanoprobes. The MNM-SPs can be navigated on-demand to avoid obstacles and target sensing sites by the guidance of an external gradient magnetic field. Through applying a rotating magnetic field, the MNM-SPs can actively rotate to efficiently stir and mix surrounding fluid and thus contact with analytes quickly for SERS sensing. Innovatively, we demonstrate the self-cleaning capability of the MNM-SPs which can be used to overcome the contamination problem of traditional single-use SERS probes. Furthermore, the MNM-SPs could precisely approach the targeted single cell and then enter into the cell by endocytosis. It is worth mentioning that by the effective mixing of intracellular biocomponents, much more informative Raman signals with improved signal-to-noise ratio can be captured after active rotation. Therefore, the demonstrated magnetically activated MNM-SPs that are endowed with SERS sensing capability pave way to the future development of smart sensing probes with maneuverability for biochemical analysis at the micro-/nanoscale.

Development of an axial rotating magnetic field multi-coil eddy current sensor for electromagnetic characterization of stratified CFRP materials

2021 ◽  
pp. 102589
Author(s):  
Ahmed Chaouki Lahrech ◽  
Mohammed Naidjate ◽  
Bachir Helifa ◽  
Abdelhalim Zaoui ◽  
Bachir Abdelhadi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Rotating Magnetic Field ◽  
Current Sensor ◽  
Eddy Current Sensor

Remote Field Eddy Current Control Using Rotating Magnetic Field Transducer: Application to Pressure Tubes Examination

2008 ◽  
Vol 19 (4) ◽  
pp. 202-218 ◽  
Author(s):  
Raimond Grimberg ◽  
Lalita Udpa ◽  
Adriana Savin ◽  
Rozina Steigmann ◽  
Petrica Vizureanu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Current Control ◽  
Rotating Magnetic Field ◽  
Pressure Tubes ◽  
Magnetic Field Transducer ◽  
Transducer Application
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