The Irreversibility of the Critical Currents of Polycrystalline Bulk EuBa2Cu3O7–x with Cycles in an Applied Magnetic Field

1990 ◽  
Vol 117 (2) ◽  
pp. K127-K131 ◽  
Author(s):  
Xin Jin ◽  
Xiaohui Wang ◽  
Yi Tang ◽  
Mu Lu ◽  
Yitong Zang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Critical Currents

Nondestructive Analysis of Bi2212 Bulk Superconducting Ceramics in the C-Axis Direction

2016 ◽  
Vol 869 ◽  
pp. 29-34
Author(s):  
Antonio Renato Bigansolli ◽  
T.G. da Cruz ◽  
Durval Rodrigues Jr.
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Applied Magnetic Field ◽  
Structural Parameters ◽  
Processing Technique ◽  
Critical Currents ◽  
Weak Links ◽  
Critical Temperatures ◽  
Axis Direction ◽  
Average Grain Size

The use of superconductors of high critical temperatures in applied superconductivity leads to higher operation temperatures and economy of cryogenic fluids. High temperature superconductor materials exhibits limited transport properties due to grain boundary weak-links and anisotropy on the critical currents. The texturing development in these superconductors decreases in an efficient way the number of high-angle grain boundaries, increasing the values of the critical current densities. Several quantitative analysis methods have been developed to study the morphologic and topologic characteristics improving our understanding of structural parameters. In this work the grain size distribution characterization of Bi2Sr2CaCu2O8+δ Bi2212 superconductor bulk samples heat treated under the influence of an external applied magnetic field of 5T was carried out using a processing technique and analysis of images. The analyzed images were obtained by SEM in the c axis direction. All samples showed similar microstructures on both cases, but with the use of an external applied magnetic field during the heat treatments the average grain size decreased.

Scaling of critical currents versus temperature in granular Y1Ba2Cu3O7−δ superconductors at zero applied magnetic field

1993 ◽  
Vol 215 (1-2) ◽  
pp. 105-112 ◽  
Author(s):  
A. Díaz ◽  
A. Pomar ◽  
G. Domarco ◽  
C. Torrón ◽  
J. Maza ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Critical Currents

scholarly journals Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

2021 ◽  
Author(s):  
Alexander Vakhrushev ◽  
Abdellah Kharicha ◽  
Ebrahim Karimi-Sibaki ◽  
Menghuai Wu ◽  
Andreas Ludwig ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Lorentz Force ◽  
Applied Magnetic Field ◽  
Numerical Study ◽  
Flow Direction ◽  
Experimental Studies ◽  
Submerged Entry Nozzle ◽  
Mean Flow ◽  
Slab Caster ◽  
The Mean

AbstractA numerical study is presented that deals with the flow in the mold of a continuous slab caster under the influence of a DC magnetic field (electromagnetic brakes (EMBrs)). The arrangement and geometry investigated here is based on a series of previous experimental studies carried out at the mini-LIMMCAST facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The magnetic field models a ruler-type EMBr and is installed in the region of the ports of the submerged entry nozzle (SEN). The current article considers magnet field strengths up to 441 mT, corresponding to a Hartmann number of about 600, and takes the electrical conductivity of the solidified shell into account. The numerical model of the turbulent flow under the applied magnetic field is implemented using the open-source CFD package OpenFOAM®. Our numerical results reveal that a growing magnitude of the applied magnetic field may cause a reversal of the flow direction at the meniscus surface, which is related the formation of a “multiroll” flow pattern in the mold. This phenomenon can be explained as a classical magnetohydrodynamics (MHD) effect: (1) the closure of the induced electric current results not primarily in a braking Lorentz force inside the jet but in an acceleration in regions of previously weak velocities, which initiates the formation of an opposite vortex (OV) close to the mean jet; (2) this vortex develops in size at the expense of the main vortex until it reaches the meniscus surface, where it becomes clearly visible. We also show that an acceleration of the meniscus flow must be expected when the applied magnetic field is smaller than a critical value. This acceleration is due to the transfer of kinetic energy from smaller turbulent structures into the mean flow. A further increase in the EMBr intensity leads to the expected damping of the mean flow and, consequently, to a reduction in the size of the upper roll. These investigations show that the Lorentz force cannot be reduced to a simple damping effect; depending on the field strength, its action is found to be topologically complex.

scholarly journals Stability of nonaxisymmetric ferrofluid flow in rotating cylinders with magnetic field

2005 ◽  
Vol 2005 (23) ◽  
pp. 3727-3737 ◽  
Author(s):  
Jitender Singh ◽  
Renu Bajaj
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Critical Value ◽  
Annular Space ◽  
Rotating Cylinders ◽  
The Stability

Effect of an axially applied magnetic field on the stability of a ferrofluid flow in an annular space between two coaxially rotating cylinders with nonaxisymmetric disturbances has been investigated numerically. The critical value of the ratioΩ∗of angular speeds of the two cylinders, at the onset of the first nonaxisymmetric mode of disturbance, has been observed to be affected by the applied magnetic field.

Sign in / Sign up

Export Citation Format

Share Document