MAGNETIC FORCE AND MAGNETIC INDUCTION

Author(s):  
James Clerk Maxwell
1894 ◽  
Vol 54 (326-330) ◽  
pp. 75-77 ◽  

The paper describes a series of observations of magnetic quality in vai'ious specimens of sheet iron and iron wire. A principal object was to determine the amount of energy lost in consequence of magnetic hysteresis when the iron under examination was carried through cyclic magnetising processes between assigned limits of the magnetic induction B. For this purpose observations of the relation of the induction B to the magnetic force H were made, from which curves were drawn, and the area enclosed by the curves in cyclic magnetising processes was measured.


2015 ◽  
Vol 15 (05) ◽  
pp. 1550072 ◽  
Author(s):  
O. ANWAR BÉG ◽  
D. TRIPATHI ◽  
T. SOCHI ◽  
P. K. GUPTA

The Adomian decomposition method (ADM) is applied to analyze Newtonian bio-magneto-tribological squeeze film flow with magnetic induction effects incorporated. Robust solutions are developed for the transformed radial and tangential momentum and radial and tangential induced magnetic field conservation equations. The effects of squeeze Reynolds number (N1= Rem/ Bt where Bt = Batchelor number), dimensionless axial magnetic force strength parameter (N2), dimensionless tangential magnetic force strength parameter (N3), magnetic Reynolds number ( Rem) are depicted graphically. ADM is observed to demonstrate excellent convergence, stability and versatility in simulating both magnetic squeeze film problems. Numerical verification is achieved with Nakamura's tridiagonal finite difference method (NTM). The simulations are relevant to "smart" biological bearings and prosthetics (e.g., "smart knees") exploiting magnetic fluids.


2021 ◽  
pp. 137-144
Author(s):  
Fei Liu ◽  
Zhen Lin ◽  
Dapeng Li ◽  
Tao Zhang

As the core part of precision seeder, the performance of pickup finger seed metering device directly affects the seeding quality. Aiming at the problem that the traditional pickup finger seed metering device can be easily affected by the performance of spring material, and the reliability of spring decreases with the increase of service time, a magnetic pickup finger seed metering device is designed to open and close the pickup finger by magnetic force, so as to improve the stability of seed metering performance. Through the design and optimization of permanent magnet structure, cam structure and seed taking pickup finger structure, the magnetic force distribution of ring magnet is analysed by using ANSYS Maxwell magnetic simulation software. Under the working speed of 3.9km/h, the vibration frequency, vibration amplitude and magnetic induction intensity were selected for orthogonal test. The experimental results show that the optimal combination of factors is vibration frequency 6Hz, vibration amplitude 3.1mm and magnetic induction intensity 316.34mT. Under the condition of the combination of operation parameters, the seed arrangement performance is 91.7% of the qualified rate, 6.2% of the replant rate and 2.1% of the missed rate, which meets the requirements of the national standard for the performance of the seeder. This study can provide a reference for the optimization of the structure and the improvement of the seed metering performance of the pickup finger seed metering device.


Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 341
Author(s):  
Kengo Wada ◽  
Masayuki Kaneda ◽  
Kazuhiko Suga

The convection control is important in terms of the heat transfer enhancement and improvement of the applied devices and resultant products. In this study, the convection control by a magnetic field from block permanent magnets is numerically investigated on the Rayleigh-Bénard convection of paramagnetic fluid. To enhance the magnetic force from the available permanent magnets, pairs of alternating-pole magnets are employed and aligned near the bottom heated wall. The lattice Boltzmann method is employed for the computation of the heat and fluid flow with the consideration of buoyancy and magnetothermal force on the working fluid. It is found that, since the magnetic force at the junction of pair magnets becomes strong remarkably and in the same direction as the gravity, descending convection flow is locally enhanced and the pair of symmetrical roll cells near the magnet junction becomes longitudinal. The local heat transfer corresponds to the affected roll cell pattern; locally enhanced at the magnet junctions and low heat transfer area is shifted aside the magnet outer edge. The averaged Nusselt number on the hot wall also increases proportionally to the magnetic induction but it is saturated at high magnetic induction. This suggests the roll cell pattern is no more largely affected at extremely-high magnetic induction.


2014 ◽  
Vol 595 ◽  
pp. 70-75
Author(s):  
Anna Sandulyak ◽  
Alexander Sandulyak ◽  
Vera Ershova ◽  
Alexander Snedkov ◽  
Darya Sandulyak

The unprecedented attempt has been made to fully expand classical and often quoted (above all by magnetic separation regimes and conditions analysis) expression for the force affecting the ferroparticle in magnetic field with the functional character of the following parameters of this expression being taken into account: magnetic induction, magnetic gradient and ferroparticle magnetic susceptibility. For this purpose a particular case of force impact has been analyzed in field approximating one-dimensional field. This field is produced in module of two distantly oriented magnetic elements. The obtained dependences for magnetic induction, magnetic gradient and ferroparticle magnetic susceptibility (according to distance x to polar surface one of the magnetic elements) have been used. By the analysis the fact has been taken into account that ferroparticle magnetic susceptibility depends on its shape as well as substance magnetic susceptibility depends, in its turn, on magnetic field intensity around ferroparticle. In other words, magnetic susceptibility of material depends on distance x to polar surface usually being ignored. The analysis of the following expanded variant of magnetic force expression allows to determine that phenomenological dependence (on parameter x) which has a very simple exponential form can be an alternative to this expression. Such dependence can be reasonably used by decision-making in theoretical and practical tasks of magnetic separation. The undertaken attempt to specify the role of another parameter B0 – magnetic induction on polar surface (that is often considered as the most essential) – shows the power (approximating square) character of magnetic force concerning this parameter.


2003 ◽  
Vol 12 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Vasile Murariu ◽  
Jan Svoboda

The current practice of assessing the efficiency of recovery of magnetite and ferrosilicon by drum magnetic separators is to conduct Davis tube tests at a magnetic induction equal to that on the surface of the drum. It is, however, the magnetic force or the force index, and not the magnetic field strength, that are decisive in the operation of a magneticseparator. Since the magneticfield gradients generated by Davis tube and drum magnetic separators are generally different, it is unlikely that the above practice would yield correct information. This article analyses the patterns of the force index generated by drum magnetic separators and a Davis tube operated at different field strengths. It is shown that in order to obtain a correct assessment of the efficiency of separation by a ferrite drum magnetic separator, a Davis tube should be operated at the field of about 0.1 T, which is lower than the current practice suggests. For a rare-earth drum separator the Davis tube operating field should be at least 0.3 T.


2022 ◽  
Vol 2148 (1) ◽  
pp. 012004
Author(s):  
Zhong Guan

Abstract There discovered the maximum possible magnetic induction in nature, equal to the magnetic induction at the poles of an electron’s spin, When the spin magnetic moments of two electrons are close to each other, they act on each other with the maximum possible magnetic induction, and finally entered the maximally entangled state after the energy drops. By this time, the spin magnetic moments on both sides situated in anti-parallel, between them there existed four invisible magnetic circuit, and each magnetic circuit just contain a fluxon. No matter how far the distance between the spins, owing to the inalienability of fluxon, no magnetic flux leakage (coupling degree 100%), so these four magnetic circuit will always existed, maintaining the maximally entangled state system immutably. This is the material basis for the entangled state to be existed, nothing to do with “spooky action at a distance”. In this paper, a visual schematic diagram has drawn to describe these, and the magnetic force state, force relationship and “light barrier” problem are analyzed.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 1461-1468
Author(s):  
Ting Dong ◽  
Juyan Huang ◽  
Bing Peng ◽  
Ling Jian

The calculation accuracy of unbalanced magnetic forces (UMF) is very important to the design of rotor length, because it will effect the shaft deflection. But in some permanent magnet synchronous motors (PMSMs) with fractional slot concentrated windings (FSCW), the UMF caused by asymmetrical stator topology structure is not considered in the existing deflection calculation, which is very fatal for the operational reliability, especially for the PMSMs with the large length-diameter ratio, such as submersible PMSMs. Therefore, the part of UMF in the asymmetrical stator topology structure PMSMs caused by the choice of pole-slot combinations is analysized in this paper, and a more accurate rotor deflection calculation method is also proposed.


2020 ◽  
pp. 3-7
Author(s):  
Vladlen Ya. Shifrin ◽  
Denis I. Belyakov ◽  
Alexander E. Shilov ◽  
Denis D. Kosenko

The results of works aimed at increasing the level of uniformity of measurements of the magnetic induction of a constant field – the basic value in the field of magnetic measurements. A set of equipment for reproducing a unit of magnetic induction of a constant field in the range of 1–25 mT was created and described. The inclusion of this complex in the State primary standard of units of magnetic induction, magnetic flux, magnetic moment and magnetic induction gradient GET 12-2011 will ensure the reproduction and direct transmission of the unit of permanent magnetic induction in the ranges of not only weak (10–3–1 mT), but medium (1–25 mT) and strong (0.025–1 T) magnetic fields. A quantum cesium magnetometer based on the resolved structure of cesium atoms was created to transmit the unit of magnetic induction to the region of medium fields. The procedure for calculating the frequency conversion coefficients to magnetic induction of the created quantum cesium magnetometer is described. The uncertainty budget for reproducing a unit of magnetic induction of a constant field using the created complex is estimated.


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