Vibration and Dynamic Instability of a Beam-Plate in a Transverse Magnetic Field

1969 ◽  
Vol 36 (1) ◽  
pp. 92-100 ◽  
Author(s):  
F. C. Moon ◽  
Yih-Hsing Pao
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Mathematical Model ◽  
Natural Frequency ◽  
Dynamic Instability ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Axial Forces ◽  
Oscillating Magnetic Field ◽  
Theoretical Results

Experiments show that the natural frequency of a beam-plate in a transverse static magnetic field decreases to near zero as the field attains a critical value which causes the same plate to buckle statically. Under an oscillating magnetic field the beam-plate is observed to become unstable and perform parametrically excited oscillations. A mathematical model based on a quasistatic solution for the magnetization in the deformed plate is proposed. The theoretical results agree very well with the experimental data. It is shown that the phenomena are analogous to those for a beam-column under static and dynamic axial forces.

scholarly journals Influence of Magnetic Field on the Peristaltic Flow of a Viscous Fluid through a Finite-Length Cylindrical Tube

2010 ◽  
Vol 7 (3) ◽  
pp. 169-176 ◽  
Author(s):  
S. K. Pandey ◽  
Dharmendra Tripathi
Keyword(s):  
Magnetic Field ◽  
Viscous Fluid ◽  
Transverse Magnetic Field ◽  
Finite Length ◽  
Flow Rate ◽  
Hartmann Number ◽  
Volume Flow Rate ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Volume Flow

The paper presents an analytical investigation of the peristaltic transport of a viscous fluid under the influence of a magnetic field through a tube of finite length in a dimensionless form. The expressions of pressure gradient, volume flow rate, average volume flow rate and local wall shear stress have been obtained. The effects of the transverse magnetic field and electrical conductivity (i.e. the Hartmann number) on the mechanical efficiency of a peristaltic pump have also been studied. The reflux phenomenon is also investigated. It is concluded, on the basis of the pressure distribution along the tubular length and pumping efficiency, that if the transverse magnetic field and the electric conductivity increase, the pumping machinery exerts more pressure for pushing the fluid forward. There is a linear relation between the averaged flow rate and the pressure applied across one wavelength that can restrain the flow due to peristalsis. It is found that there is a particular value of the averaged flow rate corresponding to a particular pressure that does not depend on the Hartmann number. Naming these values ‘critical values’, it is concluded that the pressure required for checking the flow increases with the Hartmann number above the critical value and decreases with it below the critical value. It is also inferred that magneto-hydrodynamic parameters make the fluid more prone to flow reversal. The conclusion applied to oesophageal swallowing reveals that normal water is easier to swallow than saline water. The latter is more prone to flow reversal. A significant difference between the propagation of the integral and non-integral number of waves along the tube is that pressure peaks are identical in the former and different in the latter cases.

Article

1998 ◽  
Vol 76 (7) ◽  
pp. 507-513
Author(s):  
O Bolina ◽  
J R Parreira
Keyword(s):  
Magnetic Field ◽  
Transverse Magnetic Field ◽  
Ground State ◽  
Linear Chain ◽  
Critical Value ◽  
Transverse Magnetic ◽  
The State ◽  
Xy Model ◽  
The Magnetic Field

We show that the ground state of the xy model (ferromagnetic orantiferromagnetic) in a transverse magnetic field h --- for any spin value, in any dimension --- is the state with all spins aligned antiparallel to the field when h is greater than some critical value hc. In particular, for the spin-1/2 linear chain, we study the behavior of correlations as functions of the magnetic field. PACS Nos.: 75.10Jm and 64.60.Cm

Model of a Thin Rod with Viscoelastic Magnetizablematerial in the Alternating Magnetic Field

2012 ◽  
Vol 190 ◽  
pp. 629-632 ◽  
Author(s):  
Klaus Zimmermann ◽  
Igor Zeidis ◽  
V.A. Naletova ◽  
S.A. Kalmykov ◽  
V.A. Turkov
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Vertical Plane ◽  
Alternating Magnetic Field ◽  
Numerical Calculations ◽  
Theoretical Results ◽  
2D Model

The motion of a thin rod with viscoelastic magnetizable material in a channelunder the action of the alternating magnetic field of the coils is considered experimentally andtheoretically. The dynamic 2D model of a thin rod with viscoelastic magnetizable material isused. Numerical calculations of the rod motion in a vertical plane under the action of alternatingmagnetic field, gravity and friction are performed using this model. An influence of parametersof the problem on the rod velocity is studied theoretically. Theoretical results are comparedwith experimental data.

Onset of folding in plane liquid films

1996 ◽  
Vol 307 ◽  
pp. 85-99 ◽  
Author(s):  
A. L. Yarin ◽  
B. M. Tchavdarov
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Critical Value ◽  
Liquid Films ◽  
One Dimensional ◽  
Flow Parameters ◽  
Dimensional Approximation ◽  
Plane Jets ◽  
Oscillation Frequencies ◽  
Theoretical Results

The onset of the folding effect characteristic of highly viscous liquid films (plane jets) slowly impinging on a wall is studied. Nonlinear quasi-one-dimensional equations are derived to describe the flow. In the linear approximation they reduce to the eigenvalue problem, whose solution predicts that instability (the onset of folding) sets in when the length of the film exceeds a critical value. The critical folding heights and the oscillation frequencies at the onset of instability are predicted as a function of flow parameters. Theoretical results are compared with Cruickshank's (1988) experimental data. Agreement is quite good only in the range of parameters where the quasi-one-dimensional approximation is applicable (thin films at the onset of folding).

Relaxation of magnetic field in a plasma via the tearing mode

1986 ◽  
Vol 35 (2) ◽  
pp. 311-317 ◽  
Author(s):  
S. K. H. Auluck
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Tearing Mode ◽  
Simple Argument ◽  
Theoretical Results

A simple argument based on energetics is presented to bring out the similarities between diverse plasmas which undergo current filamentation. The predictions of this argument are found to be in agreement with more detailed theoretical results and experimental data.

scholarly journals VACUUM BIREFRINGENCE CAUSED BY ARBITRARY SPIN PARTICLES

2008 ◽  
Vol 23 (04) ◽  
pp. 245-248 ◽  
Author(s):  
S. I. KRUGLOV
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Laser Beam ◽  
Transverse Magnetic Field ◽  
Vacuum Polarization ◽  
Transverse Magnetic ◽  
Arbitrary Spin ◽  
Effective Lagrangian ◽  
Linearly Polarized ◽  
Higher Spin

We study the propagation of a linearly polarized laser beam in the external transverse magnetic field taking into consideration the vacuum polarization by arbitrary spin particles. Induced ellipticity of the beam is evaluated using the effective Lagrangian. With the help of the PVLAS experimental data, we obtain bounds on masses of charged higher spin particles contributed to ellipticity.

scholarly journals Distribution of the charged particles of a gas-discharge laser plasma in a transverse magnetic field. II. Experimental study

2021 ◽  
Vol 2059 (1) ◽  
pp. 012014
Author(s):  
S A Martsinukov ◽  
D K Kostrin
Keyword(s):  
Magnetic Field ◽  
Mathematical Model ◽  
Experimental Study ◽  
Transverse Magnetic Field ◽  
Positive Column ◽  
Charged Particles ◽  
Transverse Magnetic ◽  
Gas Discharge ◽  
Gas Mixture ◽  
Discharge Laser

Abstract The paper presents an experimental verification of the adequacy of a physical and mathematical model describing the influence of an external transverse magnetic field on the distribution of the charged particles in a positive column of a gas discharge. A gas-discharge laser located in a transverse magnetic field was used to conduct the study. The vacuum installation allows pumping out the system and feeding the gas mixture into it under a certain pressure. The data obtained during the experiments differ from the calculated ones by no more than 4–5 %.

scholarly journals Identification of dominant error parameters in spectrum measured by TDEMI system

ACTA IMEKO ◽  
2015 ◽  
Vol 4 (1) ◽  
pp. 61
Author(s):  
Miroslav Kamenský ◽  
Karol Kovác
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Time Domain ◽  
Electromagnetic Interference ◽  
Dynamic Range ◽  
Measuring Systems ◽  
Analog To Digital ◽  
Time Domain Electromagnetic ◽  
Parallel Input ◽  
Theoretical Results

Multiresolution analog-to-digital converters (MRADC) are usually used in Time Domain ElectroMagnetic Interference (TDEMI) measuring systems for very fast signal sampling with a sufficient dynamic range. The properties of the spectrum measured by the TDEMI system influenced by imperfections in the MRADC are analyzed in this paper. Errors are caused by imperfect matching of the offset and gain and phase of the circuits used in parallel input channels typical for the MRADC. For deep analyses of MRADC behavior, a precise mathematical model has been created using the concept of additive error pulses. Furthermore, a dedicated process of the identification of discrepancy parameters from experimental data is proposed. Identified parameters enter the expressions of the model and enable side to side comparison of experimental and theoretical results.

Magnetoelastic Buckling of Thin Magnetically Soft Plates in Cylindrical Mode

1974 ◽  
Vol 41 (1) ◽  
pp. 145-150 ◽  
Author(s):  
J. M. Dalrymple ◽  
M. O. Peach ◽  
G. L. Viegelahn
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Rectangular Plate ◽  
Empirical Formula ◽  
Uniform Magnetic Field ◽  
Critical Value ◽  
Elliptical Plate ◽  
Wide Face ◽  
Magnetically Soft Material ◽  
Plate Width

When a plate of magnetically soft material is supported with its wide face normal to a uniform magnetic field, it will buckle when the field reaches a critical value. It is shown theoretically that the critical buckling field for a “half-restrained” rectangular plate should be 0.833 of that for a half-restrained elliptical plate of identical dimensions and material. Limited experimental data support this conclusion. The effect of plate width upon critical buckling field is investigated experimentally and an empirical formula is presented which fits the data reasonably well.

scholarly journals MAGNETO-ABSORPTION IN ELLIPSOIDAL QUANTUM DOT

2012 ◽  
Vol 15 ◽  
pp. 40-47 ◽  
Author(s):  
K.G. DVOYAN ◽  
V.V. EVOYAN ◽  
E.M. KAZARYAN ◽  
R.G. NAZMITDINOV ◽  
H.A. SARKISYAN
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Perturbation Theory ◽  
Quantum Dot ◽  
Absorption Coefficient ◽  
Normal Modes ◽  
Luminescence Method ◽  
Absorption Of Light ◽  
Ellipsoidal Quantum Dot ◽  
Theoretical Results

The absorption of light in ellipsoidal quantum dot in the presence of a magnetic field is discussed using perturbation theory. Also the same problem is discussed using the normal modes. Quantum dot absorption coefficient is calculated – as well as threshold frequency of absorption – as a function of applied magnetic field. Theoretical results are compared with experimental data obtained by magneto-luminescence method in In0.53Ga0.47As quantum dot (M. Bayer et al, PRB vol.53, pp. 15810–15814, 1996).

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