52,928 research outputs found
Research of Magnetic Field Distribution in the Working Area of Disk Separator, Taking Into Account an Influence of Materials of Permanent Magnets
Based on the results of a numerical-field analysis of the distribution of the magnetic force field in the working area of the disk magnetic separator, designed to clean bulk substances from ferromagnetic inclusions, the influence of the magnetic material of the poles of the magnetic system on the field distribution is determined. A consistent study of two magnetic systems assembled on the basis of magnetic materials of different classes is carried out. The finite element method implemented in the COMSOL Multiphysics software environment is used to calculate the distribution of magnetic induction in a disk magnetic separator with rare-earth and ferrite magnets. Due to the complexity of the spatial geometry of the force field in the working area of the disk magnetic separator, a three-dimensional model of the magnetic system is developed. A comparative analysis of the distribution of the magnetic force field in the working area of the disk separator with a highly coercive magnetic system and with a magnetic system based on ferrite blocks is carried out. As a result of the analysis, it is found that the indicators of the intensity and heterogeneity of the magnetic field for a highly coercive magnetic system significantly exceed the corresponding parameters of a ferrite magnetic system. It is proved that when choosing magnets for the magnetic system of a disk separator, preference should be given to highly coercive alloys, the magnetic properties of which significantly exceed the magnetic properties of ferrite magnets. To reduce the cost of the magnetic system of the disk separator, the use of a combined magnetic system assembled from magnetic materials of different classes is proposed. Studies of combined magnetic systems with various mass fractions of magnetic materials are done. The ratio of the mass fractions of magnets of various properties in the poles of the magnetic system is determined, at which sufficiently high magnetic characteristics are provided in the working area. It is shown that the presence of a ferrite fraction in the magnetic poles not only reduces the cost of the magnetic system of the separator, but also reduces the mass of the system. The tasks of further research are justifie
Mesogranulation and the solar surface magnetic field distribution
The relation of the solar surface magnetic field with mesogranular cells is
studied using high spatial (~ 100 km) and temporal (~ 30 sec) resolution data
obtained with the IMaX instrument aboard SUNRISE. First, mesogranular cells are
identified using Lagrange tracers (corks) based on horizontal velocity fields
obtained through Local Correlation Tracking. After ~ 20 min of integration, the
tracers delineate a sharp mesogranular network with lanes of width below about
280 km. The preferential location of magnetic elements in mesogranular cells is
tested quantitatively. Roughly 85% of pixels with magnetic field higher than
100 G are located in the near neighborhood of mesogranular lanes. Magnetic flux
is therefore concentrated in mesogranular lanes rather than intergranular ones.
Secondly, magnetic field extrapolations are performed to obtain field lines
anchored in the observed flux elements. This analysis, therefore, is
independent of the horizontal flows determined in the first part. A probability
density function (PDF) is calculated for the distribution of distances between
the footpoints of individual magnetic field lines. The PDF has an exponential
shape at scales between 1 and 10 Mm, with a constant characteristic decay
distance, indicating the absence of preferred convection scales in the
mesogranular range. Our results support the view that mesogranulation is not an
intrinsic convective scale (in the sense that it is not a primary
energy-injection scale of solar convection), but also give quantitative
confirmation that, nevertheless, the magnetic elements are preferentially found
along mesogranular lanes.Comment: Accepted for publication in ApJ Letters, 16 pages, 5 figure
Local field distribution near corrugated interfaces: Green's function formulation
We have developed a Green's function formalism to compute the local field
distribution near an interface separating two media of different dielectric
constants. The Maxwell's equations are converted into a surface integral
equation; thus it greatly simplifies the solutions and yields accurate results
for interfaces of arbitrary shape. The integral equation is solved and the
local field distribution is obtained for a periodic interface.Comment: Presented at the Conference on Computational Physics (CCP2000), held
at Gold Coast, Australia from 3 - 8, December 2000. To be published in
Proceedings of CCP200
Analytical solutions for the electric field and dielectrophoretic force in a dielectrophoretic focusing electrode structure
The analysis of the movement of particles in a nonuniform field requires accurate knowledge of theelectric field distribution. In this letter, the Schwarz–Christoffel mapping method is used to analytically solve the electric field distribution in a dielectrophoretic focusing electrode structure.The analytical result for the electric field distribution is validated by comparison with numericalsimulations using the finite element method. The electric field solution is used to calculate the dielectrophoretic force on a particle in the syste
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