Study of Microwave Reflection Behaviour in Fe3O4 Magnetorheological Fluids

2011 ◽  
Vol 287-290 ◽  
pp. 2785-2788
Author(s):  
Nan Hui Yu ◽  
Ji Jun Fan
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
External Magnetic Field ◽  
Field Strength ◽  
Smart Materials ◽  
Particle Concentration ◽  
Critical Concentration ◽  
Microwave Frequency ◽  
Magnetorheological Fluids ◽  
Microwave Reflection

Owing to its unique properties and wide engineering applications, magnetorheological fluids (MRF) has become a hot study area in the field of smart materials. In this paper experimental study of the microwave reflection behavior in MRF was carried out. The results indicated that at the same frequency the microwave reflectivity of MRF decreased with the increasing of magnetic field strength; and with the particle concentration increasing, microwave reflectivity first increased, then decreased, there is a critical concentration of 15%. Under the same magnetic field, with the increasing of microwave frequency, it first decreased, there is a lowest point at 9.2GHz, and then it increased. Usually, it is considered that the change of internal structure of MRF under external magnetic field is the main reason for the regulation behavior of microwave reflectivity.

Regulation Behavior of Microwave Reflectivity in Magnetorheological Fluids

2011 ◽  
Vol 413 ◽  
pp. 213-216
Author(s):  
Ji Jun Fan ◽  
Nan Hui Yu
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
External Magnetic Field ◽  
Field Strength ◽  
Internal Structure ◽  
Magnetic Field Strength ◽  
Particle Concentration ◽  
Microwave Frequency ◽  
Microwave Reflection ◽  
The Given

In this paper, experimental study of the microwave reflection behavior in MRF was carried out. The results showed that at the same frequency the microwave reflectivity of MRF decreased with the increasing of magnetic field strength; and with the increasing of particle concentration, microwave reflectivity decreased, monotonously. Under the given magnetic field, with the increasing of microwave frequency, it first decreased, there is a lowest point at 9.2GHz, and then it increased. Usually, it is considered that the change of internal structure of MRF under external magnetic field is the main reason for the regulation behavior of microwave reflectivity.

Effect of external magnetic field on lane formation in driven pair-ion plasmas

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Swati Baruah ◽  
U. Sarma ◽  
R. Ganesh
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Coupling Parameter ◽  
Critical Parameters ◽  
Coulomb Coupling ◽  
Lane Formation ◽  
Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

scholarly journals Magnetoviscosity of a Magnetic Fluid Based on Barium Hexaferrite Nanoplates

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1870
Author(s):  
Dmitry Borin ◽  
Robert Müller ◽  
Stefan Odenbach
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Shear Flow ◽  
Magnetic Fluid ◽  
Barium Hexaferrite ◽  
Dipole Interaction ◽  
Field Dependent ◽  
Fluid Behaviour

This paper presents the results of an experimental study of the influence of an external magnetic field on the shear flow behaviour of a magnetic fluid based on barium hexaferrite nanoplates. With the use of rheometry, the magnetoviscosity and field-dependent yield-stress in the fluid are evaluated. The observed fluid behaviour is compared to that of ferrofluids with magnetic nanoparticles having high dipole interaction. The results obtained supplement the so-far poorly studied topic of the influence of magnetic nanoparticles’ shape on magnetoviscous effects. It is concluded that the parameter determining the observed magnetoviscous effects in the fluid under study is the ratio V2/l3, where V is the volume of the nanoparticle and l is the size of the nanoparticle in the direction corresponding to its orientation in the externally applied magnetic field.

Experimental Study of a Plasma Produced by a Helical Radio-frequency Structure

1974 ◽  
Vol 52 (22) ◽  
pp. 2246-2249 ◽  
Author(s):  
H. W. H. Van Andel ◽  
M. T. Churchland ◽  
G. Calabrese
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Field Strength ◽  
Electron Temperature ◽  
Magnetic Field Strength ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Plasma Stability ◽  
Absorption Process ◽  
Moderate Power

A plasma produced by a helical RF structure of the Lisitano type is investigated. Measurements of electron density, electron temperature, and plasma stability are reported as a function of RF frequency and power, magnetic field strength and geometry, and neutral argon pressure. It is concluded that at moderate power (~20 W), electron cyclotron resonance is important in the power absorption process.

Experimental study of the relaxation cycle of a decaying spheromak in an external magnetic field

1991 ◽  
Vol 3 (6) ◽  
pp. 1452-1460 ◽  
Author(s):  
Y. Ono ◽  
M. Yamada ◽  
A. C. Janos ◽  
F. M. Levinton
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
External Magnetic Field ◽  
Relaxation Cycle

Preliminary experimental study on applicability of Lorentz force velocimetry in an external magnetic field

2018 ◽  
Vol 29 (6) ◽  
Author(s):  
Yan-Qing Tan ◽  
Run-Cong Liu ◽  
Shang-Jun Dai ◽  
Xiao-Dong Wang ◽  
Ming-Jiu Ni ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
External Magnetic Field ◽  
Lorentz Force ◽  
Lorentz Force Velocimetry

Schwingung eines Plasmazylinders in einem axialen Magnetfeld II

1960 ◽  
Vol 15 (3) ◽  
pp. 220-226 ◽  
Author(s):  
Klaus Körper
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
External Magnetic Field ◽  
Field Strength ◽  
Axial Magnetic Field ◽  
Surface Current ◽  
The Other ◽  
Plasma Cylinder ◽  
Resonance Frequencies ◽  
The Magnetic Field

Radial oscillations are excited in a homogeneous infinite plasma cylinder in a homogeneous axial magnetic field by a surface current which is homogeneous in the axial and azimuthal directions. The modes of oscillations corresponding to the axial and azimuthal components of current are not coupled, and so they may be analysed separately. The magnetic field in the plasma and vacuum is obtained, and the indices of refraction for both types of oscillations are discussed thoroughly. When the currents are parallel to the external magnetic field, the oscillations are characterized by the refractive index of Eccles. On the other hand, when the current is perpendicular to the magnetic field two resonance frequencies exist, which depend on the density of the plasma and the magnetic field strength. — In the latter case the radial characteristic oscillations of the plasma cylinder in an external magnetic field are considered.

Experimental study of electrical discharges in gas flows under external magnetic field

2011 ◽  
Vol 49 (6) ◽  
pp. 788-796 ◽  
Author(s):  
I. B. Klementyeva ◽  
V. A. Biturin ◽  
B. N. Tolkunov ◽  
I. A. Moralev
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
External Magnetic Field ◽  
Gas Flows ◽  
Electrical Discharges

An Investigation of the Behaviour of Magnetorheological Fluids in the Rotary Shock-Absorber

2012 ◽  
Vol 628 ◽  
pp. 512-517 ◽  
Author(s):  
Sławomir Kciuk ◽  
Monika Kciuk ◽  
Roman Turczyn ◽  
Paweł Martynowicz
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Structure Formation ◽  
Internal Structure ◽  
Carbonyl Iron ◽  
Shock Absorber ◽  
Experimental Studies ◽  
Magnetorheological Fluids ◽  
Control Current

The main aim of the article was to present the investigation results of created megnetorheological fluids using carbonyl iron (CI) particles and analyse their behaviour in terms of the internal structure formation by a control of external magnetic field. Results of the experimental studies of a prototype magnetorheological rotary shock-absorber at various magnitudes of control current was presented in this paper.

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