Isothermal Martensitic Transformation in a Sensitized SUS304 Stainless Steel under Magnetic Field

We have investigated effect of magnetic field at cryogenic temperature on the stability of austenitic phase in a sensitized SUS304 stainless steel. The sensitization of the steel was made by heat-treatment in vacuum at 973 K for 100h after the solution treatment at 1323 K for 0.5 h. Isothermal holding of the sensitized specimens was made under a static magnetic field of 5 T in the temperature range between 60 and 260 K for various holding times. As a result, the TTT diagram under the magnetic field corresponding to the formation of 0.5 vol. % of -martensite shows a double-C curve with two noses. We found that by the application of magnetic field, the nose temperature and the incubation time of upper part of the C-curve, that is due to the    transformation, become lower and shorter, respectively. On the other hand, the nose temperature of lower part of the C-curve, that is due to the      transformation, does not change under the magnetic field although the incubation time shortens by the application of magnetic field.

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Uniform Internal Finishing of SUS304 Stainless Steel Bent Tube Using a Magnetic Abrasive Finishing Process

Journal of Manufacturing Science and Engineering ◽

10.1115/1.1951786 ◽

2004 ◽

Vol 127 (3) ◽

pp. 605-611 ◽

Cited By ~ 18

Author(s):

Hitomi Yamaguchi ◽

Takeo Shinmura ◽

Megumi Sekine

Keyword(s):

Magnetic Field ◽

Stainless Steel ◽

Removal Rate ◽

Surface Finishing ◽

Initial Surface ◽

Magnetic Abrasive Finishing ◽

Sus304 Stainless Steel ◽

Finishing Process ◽

Abrasive Finishing ◽

The Magnetic Field

This research studies the factors affecting the conditions required for successful uniform internal finishing of SUS304 stainless steel bent tube by a Magnetic abrasive finishing process. In particular, the effects of the magnetic field and ferrous particles were investigated. Local intensification of the magnetic field is accomplished by offsetting the axis of pole rotation from elbow axis. This effect enables local control of the material removal rate, which leads to uniformity in the finished surface regardless of the initial surface conditions. A two-phase finishing process controlling the size of the ferrous particles is proposed to achieve efficient fine surface finishing.

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No-z Model for Magnetic Fields of Different Astrophysical Objects and Stability of the Solutions

Data ◽

10.3390/data6010004 ◽

2021 ◽

Vol 6 (1) ◽

pp. 4

Author(s):

Evgeny Mikhailov ◽

Daniela Boneva ◽

Maria Pashentseva

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Large Scale ◽

Point Of View ◽

Accretion Discs ◽

Wide Range ◽

Astrophysical Objects ◽

Alpha Effect ◽

The Stability ◽

The Magnetic Field

A wide range of astrophysical objects, such as the Sun, galaxies, stars, planets, accretion discs etc., have large-scale magnetic fields. Their generation is often based on the dynamo mechanism, which is connected with joint action of the alpha-effect and differential rotation. They compete with the turbulent diffusion. If the dynamo is intensive enough, the magnetic field grows, else it decays. The magnetic field evolution is described by Steenbeck—Krause—Raedler equations, which are quite difficult to be solved. So, for different objects, specific two-dimensional models are used. As for thin discs (this shape corresponds to galaxies and accretion discs), usually, no-z approximation is used. Some of the partial derivatives are changed by the algebraic expressions, and the solenoidality condition is taken into account as well. The field generation is restricted by the equipartition value and saturates if the field becomes comparable with it. From the point of view of mathematical physics, they can be characterized as stable points of the equations. The field can come to these values monotonously or have oscillations. It depends on the type of the stability of these points, whether it is a node or focus. Here, we study the stability of such points and give examples for astrophysical applications.

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Magnetorheological fluid based on amorphous Fe-Si-B alloy magnetic particles

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x211064329 ◽

2021 ◽

pp. 1045389X2110643

Author(s):

Chuncheng Yang ◽

Zhong Liu ◽

Xiangyu Pei ◽

Cuiling Jin ◽

Mengchun Yu ◽

...

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Rheological Property ◽

Magnetic Particles ◽

Annealing Treatment ◽

Magnetorheological Fluid ◽

The Stability ◽

The Magnetic Field ◽

Amorphous Particle ◽

Better Than

Magnetorheological fluids (MRFs) based on amorphous Fe-Si-B alloy magnetic particles were prepared. The influence of annealing treatment on stability and rheological property of MRFs was investigated. The saturation magnetization ( Ms) of amorphous Fe-Si-B particles after annealing at 550°C is 131.5 emu/g, which is higher than that of amorphous Fe-Si-B particles without annealing. Moreover, the stability of MRF with annealed amorphous Fe-Si-B particles is better than that of MRF without annealed amorphous Fe-Si-B particles. Stearic acid at 3 wt% was added to the MRF2 to enhance the fluid stability to greater than 90%. In addition, the rheological properties demonstrate that the prepared amorphous particle MRF shows relatively strong magnetic responsiveness, especially when the magnetic field strength reaches 365 kA/m. As the magnetic field intensified, the yield stress increased dramatically and followed the Herschel-Bulkley model.

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The effect of the magnetic field on the stability and excitation spectrum of spin nanoclusters in anisotropic ferromagnetic chains

Low Temperature Physics ◽

10.1063/1.5078629 ◽

2018 ◽

Vol 44 (12) ◽

pp. 1331-1340 ◽

Cited By ~ 1

Author(s):

M. M. Bogdan ◽

V. I. Belan ◽

O. V. Charkina

Keyword(s):

Magnetic Field ◽

Excitation Spectrum ◽

The Stability ◽

The Magnetic Field

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The stability of viscous flow in a curved channel in the presence of a magnetic field

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1961.0190 ◽

1961 ◽

Vol 264 (1317) ◽

pp. 155-164 ◽

Cited By ~ 1

Keyword(s):

Magnetic Field ◽

Viscous Flow ◽

Uniform Magnetic Field ◽

Axial Direction ◽

Electrical Conductor ◽

Curved Channel ◽

Coaxial Cylinders ◽

Transverse Pressure ◽

The Stability ◽

The Magnetic Field

The stability of viscous flow between two coaxial cylinders maintained by a constant transverse pressure gradient is considered when the fluid is an electrical conductor and a uniform magnetic field is impressed in the axial direction. The problem is solved and the dependence of the critical number for the onset of instability on the strength of the magnetic field and the coefficient of electrical conductivity of the fluid is determined.

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The stability of viscous flow between rotating cylinders in the presence of a magnetic field

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1953.0023 ◽

1953 ◽

Vol 216 (1126) ◽

pp. 293-309 ◽

Cited By ~ 54

Keyword(s):

Magnetic Field ◽

Electrical Conductivity ◽

Viscous Flow ◽

Thermal Instability ◽

Horizontal Layer ◽

Rotational Stability ◽

Marginal Stability ◽

Inhibiting Effect ◽

The Stability ◽

The Magnetic Field

In this paper the theory of the stability of viscous flow between two rotating coaxial cylinders which has been developed by Taylor, Jeffreys and Meksyn is extended to the case when the fluid considered is an electrical conductor and a magnetic field along the axis of the cylinders is present. A differential equation of order eight is derived which governs the situation in marginal stability; and a significant set of boundary conditions for the problem is formulated. The case when the two cylinders are rotating in the same direction and the difference ( d ) in their radii is small compared to their mean (R 0 ) is investigated in detail. A variational procedure for solving the underlying characteristic value problem and determining the critical Taylor numbers for the onset of instability is described. As in the case of thermal instability of a horizontal layer of fluid heated below, the effect of the magnetic field is to inhibit the onset of instability, the inhibiting effect being the greater, the greater the strength of the field and the value of the electrical conductivity. In both cases, the inhibiting effect of the magnetic field depends on the strength of the field ( H ), the density ( ρ ) and the coefficients of electrical conductivity ( σ ), kinematic viscosity ( v ) and magnetic permeability ( μ ) through the same non-dimensional combination Q =μ 2 H 2 d 2 σ/ pv ; however, the effect on rotational stability is more pronounced than on thermal instability. A table of the critical Taylor numbers for various values of Q is provided.

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Quantum Hall effects

Quantum 20/20 ◽

10.1093/oso/9780198808350.003.0017 ◽

2019 ◽

pp. 303-322

Author(s):

Ian R. Kenyon

Keyword(s):

Magnetic Field ◽

Hall Effect ◽

Energy Gap ◽

Quantum Hall ◽

Free Electrons ◽

Electron Gases ◽

Hall Conductance ◽

Hall Effects ◽

The Stability ◽

The Magnetic Field

It is explained how plateaux are seen in the Hall conductance of two dimensional electron gases, at cryogenic temperatures, when the magnetic field is scanned from zero to ~10T. On a Hall plateau σ‎xy = ne 2/h, where n is integral, while the longitudinal conductance vanishes. This is the integral quantum Hall effect. Free electrons in such devices are shown to occupy quantized Landau levels, analogous to classical cyclotron orbits. The stability of the IQHE is shown to be associated with a mobility gap rather than an energy gap. The analysis showing the topological origin of the IQHE is reproduced. Next the fractional QHE is described: Laughlin’s explanation in terms of an IQHE of quasiparticles is presented. In the absence of any magnetic field, the quantum spin Hall effect is observed, and described here. Time reversal invariance and Kramer pairs are seen to be underlying requirements. It’s topological origin is outlined.

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On the stability of a general magnetic field topology in stellar radiative zones

EAS Publications Series ◽

10.1051/eas/1982032 ◽

2019 ◽

Vol 82 ◽

pp. 365-371

Author(s):

K. Augustson ◽

S. Mathis ◽

A. Strugarek

Keyword(s):

Magnetic Field ◽

Global Change ◽

Magnetic Fields ◽

Potential Energy ◽

Massive Stars ◽

Spherical Geometry ◽

Stable Region ◽

Magnetic Field Topology ◽

The Stability ◽

The Magnetic Field

This paper provides a brief overview of the formation of stellar fossil magnetic fields and what potential instabilities may occur given certain configurations of the magnetic field. One such instability is the purely magnetic Tayler instability, which can occur for poloidal, toroidal, and mixed poloidal-toroidal axisymmetric magnetic field configurations. However, most of the magnetic field configurations observed at the surface of massive stars are non-axisymmetric. Thus, extending earlier studies in spherical geometry, we introduce a formulation for the global change in the potential energy contained in a convectively-stable region for both axisymmetric and non-axisymmetric magnetic fields.

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Rayleigh–Bénard convection and pattern formation in magnetohydrodynamics

Journal of Plasma Physics ◽

10.1017/s0022377898006989 ◽

1998 ◽

Vol 60 (3) ◽

pp. 529-539 ◽

Cited By ~ 1

Author(s):

RENU BAJAJ ◽

S. K. MALIK

Keyword(s):

Magnetic Field ◽

Steady State ◽

Thermal Instability ◽

Electrically Conducting ◽

Electrically Conducting Fluid ◽

Steady State Bifurcation ◽

The Stability ◽

Rayleigh Benard Convection ◽

Rayleigh Benard ◽

The Magnetic Field

A nonlinear thermal instability in a layer of electrically conducting fluid in the presence of a magnetic field is discussed. Steady-state bifurcation results in the formation of patterns: rolls, squares and hexagons. The stability of various patterns is also investigated. It is found that in the absence of a magnetic field only rolls are stable, but when the magnetic field strength exceeds a certain finite value, squares and hexagons also become stable.

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