Magnetoelastic Buckling of a Thin Plate

1968 ◽  
Vol 35 (1) ◽  
pp. 53-58 ◽  
Author(s):  
F. C. Moon ◽  
Yih-Hsing Pao
Keyword(s):  
Magnetic Field ◽  
Axial Load ◽  
Uniform Magnetic Field ◽  
Field Experiments ◽  
Equilibrium Configuration ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Field Equations ◽  
Magnetostatic Field ◽  
Characteristic Values

The instability of a column under axial load is well known. A similar phenomenon is discussed in this paper for a beam-plate in a transverse magnetic field. Experiments show that the beam may buckle (in the sense of an Euler column) when the uniform magnetic field strength reaches a critical value. A mathematical model is proposed with distributed magnetic torques along the plate. A nontrivial adjacent equilibrium configuration satisfying the magnetostatic field equations is shown to exist for characteristic values of the external magnetic field. Results as predicted from this model compare favorably with experiments.

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

THE EINSTEIN–BRILLOUIN–KELLER ACTION QUANTIZATION FOR DIRAC FERMIONS

2011 ◽  
Vol 25 (08) ◽  
pp. 537-549 ◽  
Author(s):  
P. ONORATO
Keyword(s):  
Magnetic Field ◽  
Carbon Nanostructures ◽  
Uniform Magnetic Field ◽  
Graphene Nanoribbons ◽  
Maslov Index ◽  
Transverse Magnetic ◽  
Dirac Fermions ◽  
Integral Calculus ◽  
Classical Trajectories

The Einstein–Brillouin–Keller semiclassical quantization and the topological Maslov index are used to compute the electronic structure of carbon based nanostructures with or without transverse magnetic field. The calculation is based on the Dirac Fermions approach in the limit of strong coupling for the pseudospin. The electronic bandstructure for carbon nanotubes and graphene nanoribbons are discussed, focusing on the role of the chirality and of the unbonded edges configuration respectively. The effects of a transverse uniform magnetic field are analyzed, the different kinds of classical trajectories are discussed and related to the corresponding energies. The development is concise, transparent, and involves only elementary integral calculus and provides a conceptual and intuitive introduction to the quantum nature of carbon nanostructures.

scholarly journals INFLUENCE OF A UNIFORM MAGNETIC FIELD ON DYNAMICAL CHIRAL SYMMETRY BREAKING IN QED3

2012 ◽  
Vol 27 (09) ◽  
pp. 1250026 ◽  
Author(s):  
JIAN-FENG LI ◽  
HONG-TAO FENG ◽  
YU JIANG ◽  
WEI-MIN SUN ◽  
HONG-SHI ZONG
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Uniform Magnetic Field ◽  
Cuprate Superconductors ◽  
Chiral Symmetry Breaking ◽  
Critical Value ◽  
Dynamical Chiral Symmetry Breaking ◽  
The Magnetic Field

We study dynamical chiral symmetry breaking (DCSB) in an effective QED3 theory of d-wave high temperature cuprate superconductors under a uniform magnetic field. At zero temperature, the external magnetic field induces a mixed state by generating vortices in the condensate of charged holons. The growing magnetic field suppresses the superfluid density and thus reduces the gauge field mass which is opened via the Anderson–Higgs mechanism. By numerically solving the Dyson–Schwinger gap equation, we show that the massless fermions acquires a dynamical gap through DCSB mechanism when the magnetic field strength H is above a critical value H c and the fermion flavors N is below a critical value N c . Further, it is found that both N c and the dynamical fermion gap increase as the magnetic field H grows. It is expected that our result can be tested in phenomena in high temperature cuprate superconductors.

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.

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.

The thermal and electrical resistance of tin in the intermediate state

1966 ◽  
Vol 289 (1418) ◽  
pp. 377-401 ◽  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Intermediate State ◽  
Electrical Resistance ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Thermal Resistivity ◽  
Measured Temperature ◽  
Domain Configuration ◽  
Unique Variation

The thermal and electrical conductivity of tin in its intermediate state has been measured over the temperature range 1·5 to 3·7 °K. The specimens were in the form of cylindrical single crystals with resistance ratios of from 300 to 50 000. Unlike earlier work, particular attention was directed to setting up a domain configuration of known form. It has been found that, provided the transverse magnetic field employed in establishing the intermediate state is suitably rotated as its strength is slowly increased, and provided a small electric current (of some few tenths per cent of the critical) simultaneously flows along the specimen, the thermal resistance is reproducible and stable with time. In addition, a unique variation of electrical resistance with field, which is linear up to the highest temperature examined, of 3·0 °K, is always obtained under these conditions. It is argued that the intermediate state established by this means consists of a stack of cylindrical superconducting and normal laminae. There is strong evidence to suggest that no domains are eliminated in an increasing field until the critical value is reached; when they suddenly disappear and the therm al resistance falls discontinuously to its normal state value. No corresponding discontinuities are observed when the field is reduced to half the critical temperature. Qualitative explanations are offered for these phenomena. The measured temperature variation of the thermal resistivity in the intermediate state is in satisfactory agreement with the theory of Andreev. Magnetothermal resistive effects have also been studied.

Magnetoelastic Buckling of Beams and Thin Plates of Magnetically Soft Material

1972 ◽  
Vol 39 (2) ◽  
pp. 451-455 ◽  
Author(s):  
D. V. Wallerstein ◽  
M. O. Peach
Keyword(s):  
Magnetic Field ◽  
Theoretical Result ◽  
Cantilever Beam ◽  
Uniform Magnetic Field ◽  
Critical Value ◽  
Soft Material ◽  
Thin Plates ◽  
Magnetically Soft Material ◽  
Plate Geometry ◽  
Special Case

When a plate of magnetically soft material is supported with its wide surface normal to a uniform magnetic field, it will buckle when the field reaches a critical value. This paper formulates the problem quite generally for thin plates (including beams) and carries the solution as far as can be done without making specific assumptions as to plate geometry and constraints. The special case of wide cantilever beam, considered earlier by Moon and Pao, is carried through in detail. It is shown that if their theoretical result is modified to take account of the increased field intensity caused by the plate, agreement with experiment is within 20 percent.

scholarly journals Heat Flux of a Transferred Arc Driven by a Transverse Magnetic Field

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Naomi Matsumoto ◽  
Takashi Usami ◽  
Ikumi Kuno ◽  
Takeo Yamamoto ◽  
Masaya Sugimoto ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Theoretical Model ◽  
Magnetic Flux ◽  
Field Experiments ◽  
Transverse Magnetic ◽  
Magnetic Flux Density ◽  
Dc Magnetic Field ◽  
Transferred Arc ◽  
Theoretical Predictions

Theoretical consideration of a magnetically driven arc was performed to elucidate the variation of heat flux with an imposed DC magnetic field. Experiments were conducted to confirm the validity of the theoretical model. The heat flux decreased concomitantly with increased imposed magnetic flux density. Theoretical predictions agreed with experimental results.

Sign in / Sign up

Export Citation Format

Share Document