scholarly journals Towards a model of chain-by-chain magnetization of a granular medium: a variant of magnetic diagnostics of chains of spheres

2021 ◽  
Vol 9 (5) ◽  
pp. 36-44
Author(s):  
A. A. Sandulyak ◽  
D. A. Sandulyak ◽  
Yu. О. Gorpinenko ◽  
V. A. Ershova ◽  
A. V. Sandulyak
Keyword(s):  
Magnetic Flux ◽  
Magnetic Permeability ◽  
Magnetic Induction ◽  
Granular Medium ◽  
Printed Circuit Boards ◽  
Contact Point ◽  
Magnetic Parameters ◽  
The Core ◽  
Magnetic Diagnostics ◽  
A Chain

In addition to information on the magnetic parameters of inhomogeneous magnetics, in particular, granular magnetics usually studied within the framework of the quasi-continuous medium model, it is of no less interest to obtain information from the standpoint of the model, when the object of study is the characteristic elements of an inhomogeneous magnetic. According to the well-proven model of selective magnetization of a granular medium, the elements that make up this medium are chains of granules – straight and sinuous, always manifesting themselves in the direction of its magnetization. They perform the function of conductor channels of the generated magnetic flux through the granular medium. As a result, it is a kind of branched «bundle» of conductor channels. For any of the chains of granules, for example, granules-balls of radius R, conceptually significant are the magnetic parameters of its conditional cores with radius r ≤ R, and these parameters, first of all, the magnetic permeability of quasi-continuous cores and magnetic induction in them, for different (in r) cores are variable, which requires appropriate magnetic diagnostics. To clarify the magnetic parameters of the conditional cores of a chain of granules-balls, as a physically self-sufficient element of a granular medium (i.e., in accordance with the model of chain-link magnetization of such a medium), it is practical to make measuring magnetic flux sensors in the core as circular sensors surrounding the contact point of granules-balls, however, not as traditional wire loops, but as circuits on thin printed circuit boards (with mounting holes) placed between adjacent balls. Based on the obtained data of the magnetic flux in cores of different radii r (r/R = 0.2–0.9) of a chain of spheres with a radius of R = 20 mm, the values of the magnetic induction B in them, as well as their magnetic permeability μ, were determined when the chain is magnetized in the solenoid by a field of strength from 4.8 to 54.5 kA/m. It is shown that with formal thickening of the cores, the values of B and μ decrease due to a decrease in the volume of the ferromagnet in the core, and for the limiting core (r/R → 1), i.e., for the chain as a whole, they correspond to the values of B and μ for a poly-ball backfill medium.

Experimental evaluation of electric and magnetic properties of structural steel

2018 ◽  
Vol 37 (3) ◽  
pp. 1029-1038 ◽  
Author(s):  
Phamella Reinert Tamanini Piccoli ◽  
Sérgio Henrique Lopes Cabral ◽  
Luiz Fernando de Oliveira ◽  
Odirlan Iaronka ◽  
Diogo Fernando Harmel ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Structural Steel ◽  
Magnetic Permeability ◽  
Hot Spots ◽  
Short Circuit ◽  
Magnetic Losses ◽  
Content Type ◽  
The Core ◽  
Ohmic Losses ◽  
Numerical Fitting

Purpose This paper aims to present the proposition of a new experimental method for obtaining very crucial data of the structural steel that is used in the tank of oil filled power transformers, namely, the volumetric losses and the magnetic permeability, both in function of the density of magnetic flux. Although these data are not usually available, they are fundamental for helping the transformer designer in avoiding the occurrence of hot spots in the transformer tank. The adoption of a conventional Epstein frame has restrictions because of the incompatibility between it and the samples of the steel. Design/methodology/approach The basis of the proposition is the same as that of the Epstein frame, with significant attention paid to the additional losses in the winding that creates the magnetic flux to the samples in the core. These losses can be significant and are created by the harmonics of current along the windings and are summed to the ohmic losses. For separating these winding losses from the magnetic losses, each sample is made as being the core of a toroidal 1:1 transformer. Thus, two tests with two identic of these toroidal transformers are necessary. Findings The proposed methodology is simple, because it is very similar to the classical tests of transformers (no-load and short-circuit tests). The process of separation of losses requires only a numerical fitting of curves for adjusting the winding losses as a function of the current amplitude, and the obtained results are coherent with the expected behavior of the magnetic losses and the magnetic permeability of a structural steel. Research limitations/implications The method gives very approximate results in comparison to those obtained using the Epstein frame. The influences of the temperature and/or of the skin effect have not been evaluated. Practical implications Practical, real and thus confident data of structural steel, such as the magnetic permeability and the volumetric losses (hysteresis and Foucault), become available for the transformer designer to take actions for not only reducing the tank losses but also for avoiding the occurrence of hot spots through computer simulation. Originality/value The proposition is very new, as it allows to test steel samples with a size that does not fit to a usual Epstein frame. It takes into account the real influence of harmonic of currents in the losses along the winding of a classical Epstein frame, which has not been so far mentioned. It allows obtaining data of structural steel that had not been considered important until now.

Research on expanding the range of reproduction of magnetic flux density of the DC field of the state primary standard GET12-2011

2020 ◽  
pp. 3-7
Author(s):  
Vladlen Ya. Shifrin ◽  
Denis I. Belyakov ◽  
Alexander E. Shilov ◽  
Denis D. Kosenko
Keyword(s):  
Magnetic Flux ◽  
Magnetic Induction ◽  
Frequency Conversion ◽  
Magnetic Measurements ◽  
Primary Standard ◽  
Uncertainty Budget ◽  
The State ◽  
State Primary Standard ◽  
Magnetic Flux Density ◽  
Constant Field

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.

Селективный магнитный контроль толщины и степени упрочнения поверхностных слоев на стальных объектах

2021 ◽  
pp. 39-45
Author(s):  
А.В. Бызов ◽  
Д.Г. Ксенофонтов ◽  
В.Н. Костин ◽  
О.Н. Василенко
Keyword(s):  
Magnetic Flux ◽  
Internal Field ◽  
Hardened Layer ◽  
Strength Properties ◽  
Hardened Steel ◽  
Magnetic Characteristics ◽  
Surface Layers ◽  
Magnetic Parameters ◽  
Maximum Value ◽  
Tangential Field

The dependences of measured locally magnetic characteristics of surface-hardened steel objects on the thickness and physical properties of their surface layers are studied. It is shown theoretically and experimentally that a change in the thickness of the hardened layer on the surface of steel objects affects on the magnitude of the tangential field component on the surface of the object in the interpolar space significantly , as well as the change in the strength properties of the layer affects the magnitude of the magnetic flux in the "transducer-object" circuit. It is proposed to use this difference in magnetic parameters for selective testing of the surface hardening quality. It is shown that the coercive force measured locally by the internal field and the maximum value of the magnetic flux, which can be measured using a single transducer in single measuring cycle, can be used as diagnostic parameters.

scholarly journals Anisotropy of Magnetic Properties in Non-oriented Electrical Steel Sheets

1989 ◽  
Vol 11 (2-4) ◽  
pp. 159-170 ◽  
Author(s):  
M. Shiozaki ◽  
Y. Kurosaki
Keyword(s):  
Magnetic Properties ◽  
Magnetic Induction ◽  
Crystallographic Orientation ◽  
Electrical Steel ◽  
Core Loss ◽  
Fluorescent Lamp ◽  
Steel Sheets ◽  
The Core ◽  
Texture Change ◽  
Electrical Steel Sheets

The anisotropy of magnetic properties in non-oriented electrical steel sheets can be evaluated by measuring Epstein specimens in the radial directions. The magnetic properties measured on ring cores are practically equal to the approximate values of magnetic properties determined by Epstein specimens in the radial directions. Non-oriented electrical steel sheets with anisotropy are not desirable for motors but are suitable for transformers and fluorescent lamp ballasts. The core loss and magnetic induction as measured with ring specimens are better with non-oriented electrical steel sheets with anisotropy than with non-oriented electrical steel sheets with random crystallographic orientation. This phenomenon depends on the texture change of the product.

scholarly journals Impact of addition of ca on clogging of SEN and magnetic properties of non-oriented silicon steel

2019 ◽  
Vol 55 (1) ◽  
pp. 39-46
Author(s):  
W. Kong ◽  
D.G. Cang
Keyword(s):  
Magnetic Properties ◽  
Continuous Casting ◽  
Casting Speed ◽  
Magnetic Induction ◽  
Core Loss ◽  
Submerged Entry Nozzle ◽  
Silicon Steel ◽  
The Core ◽  
Dissolved Aluminum ◽  
The Impact

The submerged entry nozzle (SEN) clogging has been happening during continuous casting (or CC for short) for nonoriented silicon steel. To solve the problem, the paper studied a flow rate through SEN, a node attached to one of them, and the impact on the clogging. The results showed that when SEN is clogged seriously, the casting speed has to decrease below the target casting speed and that SEN clogging can be predicted by comparing the actual value and the theoretical one of a casting speed. Al2O3 and its composite inclusions caused the SEN clogging and the addition of Ca can solve SEN clogging during CC of the silicon steel both theoretically and practically. Furthermore, the impact of the addition of Ca on the magnetic properties of the steel were analyzed. The results showed that the core loss and the magnetic induction of the silicon steel decreased by using the addition of Ca, which generated more dissolved Aluminum, and the addition of Ca generated more harmful textures, which reduced the magnetic induction.

scholarly journals Regular reversals in the six-jet geodynamo model

2018 ◽  
Vol 62 ◽  
pp. 02014
Author(s):  
Liubov Feshchenko
Keyword(s):  
Magnetic Field ◽  
Magnetic Induction ◽  
The Core ◽  
The Earth ◽  
Free Decay ◽  
Regular Character

A low-mode geodynamo model is developed, controlled by 6-jet convection in the core of the Earth. The model contains only four modes, representing the fields of temperature, velocity, and two fields of magnetic induction. The magnetic modes was chosen by combining eight magnetic modes of free decay. There are two noise components in the model. In the model, stable regimes of generation of a magnetic field with reversals having a regular character were obtained. These reversals do not cause changes in the convection structure.

scholarly journals Designing a Cartridge Winder with Electronic Control

2014 ◽  
Vol 9 (2) ◽  
pp. 155892501400900 ◽  
Author(s):  
Pragnya Sanjiv Kanade ◽  
Someshwar S. Bhattacharya
Keyword(s):  
Laboratory Model ◽  
Electronic Control ◽  
Core Tube ◽  
Feed Material ◽  
The Core ◽  
Dyeing Process ◽  
Recent Trends ◽  
Precision System ◽  
A Chain ◽  
Filter Cartridge

There are number of winding machines in the market based on either the Random, Precision, or Step Precision winding system. Filtration application requires a uniform lay of yarn or its performance may be affected, hence, for the aforesaid purpose, the precision system would be more apt. Recent trends show an increased use of electronics in all applications, textiles being no exception. The aim of the present work was to develop a filter cartridge winder (laboratory model) based on the precision winding system, controlled electronically. The novelty of this machine lies in the fact that it makes use of a chain to reciprocate the guide mounted on it, unlike the majority of commercial filter winders, which make use of scroll cams to traverse the yarn. Filter winders are specialized winders that produce cartridges in standard sizes of 10”, 20”, 30″ and up to 70”. Thus a cartridge winder is quite different from the usual winding machines not only in terms of its traverse length and feed material but also because of the core tube which has to be perforated just as one required for a dyeing process.

Photospheric Flux Changes and the MHD Approximation

1984 ◽  
Vol 5 (4) ◽  
pp. 500-502 ◽  
Author(s):  
P. R. Wilson
Keyword(s):  
Magnetic Flux ◽  
Magnetic Induction ◽  
Closed Curve ◽  
Rate Of Change ◽  
Plasma Velocity ◽  
Magnetic Diffusivity

The rate of change of magnetic flux Ф contained within a closed curve C moving with the plasma velocity u, is given bywhere B is the magnetic induction and S is a surface bounded by the curve C. Using the hydromagnetic equation,where η is the magnetic diffusivity, this becomesIn many astrophysical contexts η is small and thus approximatelySince this implies that the flux within any moving closed curve does not change, the field is said to be ‘frozen into’ the plasma and moving with it.

The Regular Pattern of Demagnetizing Factor Behaviour of Various ‘Cores’ of Granule-Ball Chains

2015 ◽  
Vol 1083 ◽  
pp. 75-79
Author(s):  
Alexander Sandulyak ◽  
Anna Sandulyak ◽  
Vera Ershova ◽  
Petr Shkatov
Keyword(s):  
Granular Medium ◽  
Granular Media ◽  
Relative Size ◽  
Regular Pattern ◽  
Magnetic Media ◽  
Full Agreement ◽  
The Core ◽  
Demagnetizing Factor ◽  
Ferro Magnetic ◽  
The One

We analyze previously not studied issue on the value, nature and manifestation f a demagnetizing factor of effective channels-magnets formed in magnetized granular media by the chains of contacting granules. We provide the factor values for conditionally defined quasi-solid cores of the channels varying in length and diameter, as well as a corresponding consolidating expression which turned out to be exponential with such an argument as the radical of the core relative size. We emphasize full agreement of this expression with the one for a granular medium, i.e. the medium consisting, basically, of the effective channels bundle according to the developed theory of channel-by-channel (selective) magnetization of granular ferro-magnetic media used, e.g. as operating elements in versatile magnetic separators.

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