Field Topography of Defects in Magnetic Non-Destructive Testing

The defect parameters can be evaluated by defect induced magnetic field topography using Hall sensor. Investigations were carried out on specially prepared samples with artificial defects. According to calculations and tests tangential component of magnetic field strength extremes were detected values on either side of the defect in the surface layer l only. But this effect can not be detected by Hall sensors or Foerster probes due to their sizes. The normal component of the magnetic field strength provides a sufficiently accurate determination of the fault location, where this component becomes zero between the two extreme values located quite close to each other. The results of the study showed that at distances available to Hall transducers one can confine to the experimental research, whereas computational methods shall be used to study the topography of field defects at very small distances from the surface. This could open the prospects for testing at small distances from the surface of the object.

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Modelling and observations: Comparison of the magnetic field properties in a prominence

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936656 ◽

2020 ◽

Vol 637 ◽

pp. A3 ◽

Cited By ~ 1

Author(s):

D. H. Mackay ◽

B. Schmieder ◽

A. López Ariste ◽

Y. Su

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Magnetic Field Strength ◽

Normal Component ◽

Flux Rope ◽

Alternative Methods ◽

Stokes Parameters ◽

Line Of Sight ◽

Solar Prominences ◽

The Magnetic Field

Context. Direct magnetic field measurements in solar prominences occur infrequently and are difficult to make and interpret. As a consequence, alternative methods are needed to derive the main properties of the magnetic field that supports the prominence mass. This is important for our understanding of solar prominences, but also for understanding how eruptive prominences may affect space weather. Aims. We present the first direct comparison of the magnetic field strength derived from spectro-polarimetric observations of a solar prominence, with corresponding results from a theoretical flux rope model constructed from on-disc normal component magnetograms. Methods. We first used spectro-polarimetric observations of a prominence obtained with the magnetograph THEMIS operating in the Canary Islands to derive the magnetic field of the observed prominence by inverting the Stokes parameters measured in the He D3 line. Next, we constructed two data-constrained non-linear force-free field (NLFFF) models of the same prominence. In one model we assumed a strongly twisted flux rope solution, and in the other a weakly twisted flux rope solution. Results. The physical extent of the prominence at the limb (height and length) is best reproduced with the strongly twisted flux rope solution. The line-of-sight average of the magnetic field for the strongly twisted solution results in a magnetic field that has a magnitude of within a factor of 1−2 of the observed magnetic field strength. For the peak field strength along the line of sight, an agreement to within 20% of the observations is obtained for the strongly twisted solution. The weakly twisted solution produces significantly lower magnetic field strengths and gives a poor agreement with the observations. Conclusions. The results of this first comparison are promising. We found that the flux rope insertion method of producing a NLFFF is able to deduce the overall properties of the magnetic field in an observed prominence.

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Study of the Possibility of Estimating the Size of the Fractional-Dimensional Surface Layer by Electromagnetic Methods

Materials Science Forum ◽

10.4028/www.scientific.net/msf.945.932 ◽

2019 ◽

Vol 945 ◽

pp. 932-937 ◽

Cited By ~ 1

Author(s):

I.R. Kuzeev ◽

V.Yu. Pivovarov

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Magnetic Field Strength ◽

Plate Thickness ◽

Tangential Component ◽

Surface Layers ◽

Electromagnetic Methods ◽

Internal Structures ◽

First Time ◽

The Magnetic Field

It is known that the surface of a solid body and its volume part are different forms of the same substance. There is a hypothesis about the presence of a transition fractional-dimensional layer, which is the "limiter" of the volume from the surface. It is assumed that this layer is able to store information about changes in the surface and internal structures of the solid. The origin of defects, leading to destruction, in most cases begins in the surface and surface layers of the metal. In this regard, the existence of fractional-dimensional layer as a subsurface structure, which has information about the properties of the whole solid, is of particular importance in the detection of possible critical defects. In order to test this hypothesis, an experiment was conducted based on measuring the magnetic field strength of a steel plate (25x25x2 mm) when its thickness was changed. With the help of sandpaper, one side of the plate was swamped, and the second remained unchanged. The measurements of the magnetic field strength components were carried out on both sides with the plate thickness decreasing by 0.08-0.1 mm from 2.0 to 0.3 mm. Applying a linear approximation to the obtained dependence of the average tangential component of the magnetic field on the plate thickness, it was found that the extrapolated approximation line comes to a point close to zero (0.01 mm). It was assumed that the value 0.01 determines the preliminary value of the fractional-dimensional layer. Such an experiment was carried out for the first time, so the results obtained so far will undoubtedly become the basis for further research in this area.

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On the Configuration of the Magnetic Field of β CrB

International Astronomical Union Colloquium ◽

10.1017/s0252921100080933 ◽

1976 ◽

Vol 32 ◽

pp. 613-622

Author(s):

I.A. Aslanov ◽

Yu.S. Rustamov

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Radial Velocity ◽

Magnetic Field Strength ◽

Complex Shape ◽

Rotation Period ◽

Field Variation ◽

Magnetic Field Variation ◽

Secular Variations ◽

The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

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Suppress of neurotransduction in injured spinal cord of rats with moderate magnetic field strength

Neuroscience Research ◽

10.1016/s0168-0102(00)81259-6 ◽

2000 ◽

Vol 38 ◽

pp. S69

Author(s):

H Tatsuoka

Keyword(s):

Magnetic Field ◽

Spinal Cord ◽

Field Strength ◽

Magnetic Field Strength ◽

Injured Spinal Cord ◽

Moderate Magnetic Field

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2D analysis of magnetic field strength in GO SiFe steel sheets

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:19982133 ◽

1998 ◽

Vol 08 (PR2) ◽

pp. Pr2-579-Pr2-582 ◽

Cited By ~ 1

Author(s):

S. Tumanski ◽

M. Stabrowski

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Magnetic Field Strength ◽

Steel Sheets

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MAGNETIC FIELD, PRESSURE AND TEMPERATURE DEPENDENT OPTICAL PROPERTIES IN A GaAs 9.0 P 1.0 QUANTUM DOT

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v6i2.1791 ◽

2014 ◽

Vol 6 (2) ◽

pp. 1178-1190

Author(s):

A. JOHN PETER ◽

Ada Vinolin

Keyword(s):

Magnetic Field ◽

Optical Properties ◽

Quantum Dot ◽

Field Strength ◽

Magnetic Field Strength ◽

Photon Energy ◽

Nonlinear Optical ◽

Binding Energies ◽

Nonlinear Optical Properties ◽

Optical Rectification

Simultaneous effects of magnetic field, pressure and temperature on the exciton binding energies are found in a 9.0 1.0 6.0 4.0 GaAs P / GaAs P quantum dot. Numerical calculations are carried out taking into consideration of spatial confinement effect. The cylindrical system is taken in the present problem with the strain effects. The electronic properties and the optical properties are found with the combined effects of magnetic field strength, hydrostatic pressure and temperature values. The exciton binding energies and the nonlinear optical properties are carried out taking into consideration of geometrical confinement and the external perturbations.Compact density approach is employed to obtain the nonlinear optical properties. The optical rectification coefficient is obtained with the photon energy in the presence of pressure, temperature and external magnetic field strength. Pressure and temperature dependence on nonlinear opticalÂ susceptibilities of generation of second and third order harmonics as a function of incident photon energy are brought out in the influence of magnetic field strength. The result shows that the electronic and nonlinear optical properties are significantly modified by the applications of external perturbations in a 9.0 1.0 6.0 4.0 GaAs P / GaAs P quantum dot.

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