3D eddy current analysis by the hybrid FE-BE method using magnetic field intensity H

1992 ◽  
Vol 28 (5) ◽  
pp. 2259-2261 ◽  
Author(s):  
T. Onuki ◽  
S. Wakao ◽  
M. Shimazaki
Author(s):  
Noriyasu Kobayashi ◽  
Souichi Ueno ◽  
Satoshi Nagai ◽  
Makoto Ochiai ◽  
Noboru Jimbo

We confirmed defect detection performance of a remote field eddy current testing (RFECT) in order to inspect a helical-coil-type double wall tube steam generator (DWTSG) with a wire mesh layer for the new-type small fast reactor 4S (Supersafe, Small and Simple). As high sensitivity techniques, to increase an indirect magnetic field intensity, we focused attention on increasing a direct magnetic field intensity in the vicinity of an exciter coil by the use of an exciter coil with a magnetic material (flux guide). We adopted horizontal type multiple detector coils with flux guides arrayed circumferentially to enhance sensitivity of radial direction. According to the experimental results, the indirect magnetic field intensity (the voltage of detector coil in the region of indirect magnetic field) increased more than 100 times by the application of the exciter and detector coils with flux guides. Finally, we detected the pinhole defect of 1 mm in diameter and 20% of outer tube thickness in depth over the wire mesh layer by the adoption of the flux guides and horizontal type multiple detector coils. And we confirmed that the RFECT probe is also useful to detect the thinning defects.


2008 ◽  
Vol 8 (3) ◽  
pp. 501-507 ◽  
Author(s):  
G. Prattes ◽  
K. Schwingenschuh ◽  
H. U. Eichelberger ◽  
W. Magnes ◽  
M. Boudjada ◽  
...  

Abstract. We present the results of ground-based Ultra Low Frequency (ULF) magnetic field measurements observed from June to August 2004 during the Bovec earthquake on 12 July 2004. Further we give information about the seismic activity in the local observatory region for an extended time span 2004 and 2005. ULF magnetic field data are provided by the South European Geomagnetic Array (SEGMA) where the experience and heritage from the CHInese MAGnetometer (CHIMAG) fluxgate magnetometer comes to application. The intensities of the horizontal H and vertical Z magnetic field and the polarization ratio R of the vertical and horizontal magnetic field intensity are analyzed taking into consideration three SEGMA observatories located at different close distances and directions from the earthquake epicenter. We observed a significant increase of high polarization ratios during strong seismic activity at the observatory nearest to the Bovec earthquake epicenter. Apart from indirect ionospheric effects electromagnetic noise could be emitted in the lithosphere due to tectonic effects in the earthquake focus region causing anomalies of the vertical magnetic field intensity. Assuming that the measured vertical magnetic field intensities are of lithospheric origin, we roughly estimate the amplitude of electromagnetic noise in the Earths crust considering an average electrical conductivity of <σ>=10−3 S/m and a certain distance of the observatory to the earthquake epicenter.


Author(s):  
Pushap Lata Sharma ◽  
Sumit Gupta

This paper deals with the convection of micropolar fluids heated and soluted from below in the presence of suspended particles (fine dust) and uniform vertical rotation and uniform vertical magnetic field in a porous medium. Using the Boussinesq approximation, the linearized stability theory and normal mode analysis, the exact solutions are obtained for the case of two free boundaries. It is found that the presence of the suspended particles number density, the rotation parameter, stable solute, magnetic field intensity and medium permeability bring oscillatory modes which were non–existent in their absence. It is found that the presence of coupling between thermal and micropolar effects, rotation parameter, solute parameter and suspended particles may introduce overstability in the system. Graphs have been plotted by giving numerical values to the parameters accounting for rotation parameter , magnetic field solute parameter, the dynamic microrotation viscosity and coefficient of angular viscosity to depict the stability characteristics, for both the cases of stationary convection and overstability. It is found that Rayleigh number for the case of overstability and stationary convection increases with increase in rotation parameter, as well as with magnetic field intensity, solute parameter and decreases with increase in micropolar coefficients and medium permeability, for a fixed wave number, implying thereby the stabilizing effect of rotation parameter, magnetic field intensity ,solute parameter and destabilizing effect of micropolar coefficients and medium permeability on the thermosolutal convection of micropolar fluids.


2019 ◽  
Vol 7 (13) ◽  
pp. 3740-3743 ◽  
Author(s):  
Ying Li ◽  
Yue Long ◽  
Guoqiang Yang ◽  
Chen-Ho Tung ◽  
Kai Song

The wavelength of amplified spontaneous emission based on liquid magnetically responsive photonic crystals can be tuned by simply changing the magnetic field intensity.


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