The Effect of Mechanical Stresses on the Coercive Force of the System of Two-Phase Interacting Nanoparticles

2014 ◽  
Vol 215 ◽  
pp. 89-94
Author(s):  
Leonid L. Afremov ◽  
Ilia G. Iliushin
Keyword(s):  
Theoretical Analysis ◽  
Coercive Force ◽  
Mechanical Stresses ◽  
Interacting Particles ◽  
Residual Saturation ◽  
Magnetostatic Interaction ◽  
Two Phase ◽  
Coated Particles ◽  
Grain Model ◽  
Hysteresis Characteristics

Within the framework of the two-phase grain model (by the example of γ-Fe203 cobalt coated particles) a theoretical analysis of the effect of uniaxial mechanical stresses on the magnetization of the system of hetero-phase interacting nanoparticle was held. It is shown that stretching leads to reduction when compression increases the coercive force Hc and doesnt change the residual saturation magnetization Irs of the system of interacting particles. "Smoothing" the hysteresis loop and "lowering" the magnetization curve, the magnetostatic interaction between particles decreases both Hc, and Irs, giving the fact that hysteresis characteristics of an ensemble of interacting nanoparticles change much more in stretching than in compression.

scholarly journals Effect of Mechanical Stresses on Coercive Force and Saturation Remanence of Ensemble of Dual-Phase Interacting Nanoparticles

2012 ◽  
Vol 557-559 ◽  
pp. 501-504
Author(s):  
Leonid Afremov ◽  
Yury Kirienko
Keyword(s):  
Theoretical Analysis ◽  
Coercive Force ◽  
Mechanical Stresses ◽  
Phase Model ◽  
Phase System ◽  
Dual Phase ◽  
Interacting Particles ◽  
Magnetostatic Interaction ◽  
Saturation Remanence

In the dual-phase model of interacting nanoparticles stretching leads to a decrease in both coercive force Hc and saturation remanence Irs , and compression — to their growth. Magnetostatic interaction between particles also decreases both Hc and Irs . Theoretical analysis was carried out in the framework of the dual-phase system of interacting particles on the example of nanoparticles γ-Fe2 O3, epitaxially coated with cobalt.

scholarly journals Effect of Mechanical Stresses on the Coercive Force of the Heterophase Non-Interacting Nanoparticles

2012 ◽  
Vol 472-475 ◽  
pp. 2199-2202 ◽  
Author(s):  
Leonid Afremov ◽  
Yury Kirienko
Keyword(s):  
Theoretical Analysis ◽  
Coercive Force ◽  
Saturation Magnetization ◽  
Exchange Interaction ◽  
Cobalt Ferrite ◽  
Uniaxial Stress ◽  
Mechanical Stresses ◽  
Residual Saturation

The theoretical analysis of the effect of uniaxial stress on the magnetization of the system of noninteracting nanoparticles is done by an example of heterophase particles of maghemite, epitaxially coated with cobalt ferrite. It is shown that stretching leads to a decrease in the coercive force Hc, and compression leads to its growth. The residual saturation magnetization Irs of nanoparticles does not change. With increasing of interfacial exchange interaction, coercive force varies nonmonotonically.

scholarly journals Магнитные состояния двухфазных синтезированных частиц Fe-=SUB=-m-=/SUB=-O-=SUB=-n-=/SUB=--Fe-=SUB=-3-x-=/SUB=-Ti-=SUB=-x-=/SUB=-O-=SUB=-4-=/SUB=-: экспериментальный и теоретический анализ

2020 ◽  
Vol 62 (9) ◽  
pp. 1527
Author(s):  
П.В. Харитонский ◽  
А.А. Костеров ◽  
А.К. Гурылёв ◽  
К.Г. Гареев ◽  
С.А. Кириллова ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Theoretical Analysis ◽  
Hydrothermal Treatment ◽  
Remanent Magnetization ◽  
Sol Gel ◽  
Magnetostatic Interaction ◽  
Two Phase ◽  
Gel Method ◽  
Synthesis Conditions ◽  
Temperature Dependences

In this work, the materials of FemOn – Fe3-xTixO4 composition have been obtained using the sol-gel method and hydrothermal treatment. The synthesis conditions favor the formation of composites containing titanomagnetite in a rather low concentration. Based on the hysteresis curves and temperature dependences of the remanent magnetization, theoretical analysis of the composites magnetic properties has been carried out using a model of clustered two-phase particles bound with magnetostatic interaction.

scholarly journals A Two-Phase Model of Air Shock Wave Induced by Rock-Fall in Closed Goaf

2017 ◽  
Author(s):  
Fengyu Ren ◽  
Yang Liu ◽  
Jianli Cao ◽  
Rongxing He ◽  
Yuan Xu ◽  
...  
Keyword(s):  
Shock Wave ◽  
Theoretical Analysis ◽  
Phase Model ◽  
Rock Fall ◽  
Uniform Motion ◽  
Two Phase ◽  
Protective Measures ◽  
Computational Fluid Dynamics Cfd ◽  
Series Of Experiments ◽  
Wave Induced

In this paper, a two-phase model of air shock wave induced by rock-fall was described. The model was made up of the uniform motion phase (velocity was close to 0 m·s-1) and the acceleration movement phase. The uniform motion phase was determined by experience, meanwhile the acceleration movement phase was derived by the theoretical analysis. A series of experiments were performed to verify the two-phase model and obtained the law of the uniform motion phase. The acceleration movement phase was taking a larger portion when height of rock-fall was higher with the observations. Experimental results of different falling heights showed good agreements with theoretical analysis values. Computational fluid dynamics (CFD) numerical simulation had been carried out to study the variation velocity with different falling height. As a result of this, the two-phase model could accurately and convenient estimating the velocity of air shock wave induced by rock-fall. The two-phase model could provide a reference and basis for estimating the air shock waves' velocity and designing the protective measures.

Analysis of Remagnetization Processes of High-Anisotropic Alloy after Heat Treatment

2021 ◽  
Vol 410 ◽  
pp. 56-61
Author(s):  
Alexey S. Lileev
Keyword(s):  
Heat Treatment ◽  
Coercive Force ◽  
Structure Formation ◽  
Domain Structure ◽  
Phenomenological Approach ◽  
Thermal Treatments ◽  
Type Alloy ◽  
Magnetostatic Interaction ◽  
Increasing Process

The simulation of the Sm(Co, Fe, Cu, Zr)7.5 type alloy domain structure formation after various thermal treatments was carried out by FMRM program based on a phenomenological approach to the analysis of the uniaxial highly anisotropic ferromagnets demagnetization processes. It is shown that the domain structure of the alloy in the thermally demagnetized state expands as the coercive force of the alloy decreases. It is noted that the domains size increasing process is associated not only with a decrease in the coercive force but also with a change in the influence of the magnetostatic interaction.

Effect of Mechanical Stresses on Metastability of Heterophase Superparamagnetic Nanoparticles

2012 ◽  
Vol 602-604 ◽  
pp. 201-204
Author(s):  
Afremov Leonid ◽  
Ilia Ilyushin
Keyword(s):  
Phase Diagram ◽  
Mechanical Stresses ◽  
Superparamagnetic Nanoparticles ◽  
Magnetic Reversal ◽  
Two Phase ◽  
Magnetic States

Under the model of two-phase multiaxial nanoparticles the dependence of magnetic states and critical elds of the phases magnetic reversal on mechanical stresses has been de ned. By means of phase diagram the e ect of stresses on the basic and metastable magnetic states of heterophase particles has been studied.

A theoretical analysis of free-surface flows of saturated granular–liquid mixtures

2008 ◽  
Vol 608 ◽  
pp. 393-410 ◽  
Author(s):  
D. BERZI ◽  
J. T. JENKINS
Keyword(s):  
Free Surface ◽  
Theoretical Analysis ◽  
Eddy Viscosity ◽  
Numerical Solutions ◽  
Liquid Mixtures ◽  
Free Surface Flows ◽  
Two Phase ◽  
Surface Flows ◽  
Physical Experiments ◽  
Analytical Expressions

A simple two-phase model for steady fully developed flows of particles and water over erodible inclined beds is developed for situations in which the water and particles have the same depth. The rheology of the particles is based on recent numerical simulations and physical experiments, the rheology of the fluid is based on an eddy viscosity, and the interaction between the particles and the fluid is through drag and buoyancy. Numerical solutions of the resulting differential equations and boundary conditions provide velocity profiles of the fluid and particles, the concentration profile of the particles, and the depth of the flow at a given angle of inclination of the bed. Simple approximations permit analytical expressions for the flow velocities and the depth of flow to be obtained that agree with the numerical solutions and those measured in experiments.

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