scholarly journals The effect of magnetic field on the dynamics of gas bubbles in water electrolysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yan-Hom Li ◽  
Yen-Ju Chen
Keyword(s):  
Magnetic Field ◽  
Swirling Flow ◽  
Gas Bubbles ◽  
Water Electrolysis ◽  
Platinum Electrodes ◽  
Optimal Layout ◽  
Parallel Magnetic Field ◽  
Hydrogen Bubbles ◽  
The Magnetic Field ◽  
Sluggish Flow

AbstractThis study determines the effect of the configuration of the magnetic field on the movement of gas bubbles that evolve from platinum electrodes. Oxygen and hydrogen bubbles respectively evolve from the surface of the anode and cathode and behave differently in the presence of a magnetic field due to their paramagnetic and diamagnetic characteristics. A magnetic field perpendicular to the surface of the horizontal electrode causes the bubbles to revolve. Oxygen and hydrogen bubbles revolve in opposite directions to create a swirling flow and spread the bubbles between the electrodes, which increases conductivity and the effectiveness of electrolysis. For vertical electrodes under the influence of a parallel magnetic field, a horizontal Lorentz force effectively detaches the bubbles and increases the conductivity and the effectiveness of electrolysis. However, if the layout of the electrodes and magnetic field results in upward or downward Lorentz forces that counter the buoyancy force, a sluggish flow in the duct inhibits the movement of the bubbles and decreases the conductivity and the charging performance. The results in this study determine the optimal layout for an electrode and a magnetic field to increase the conductivity and the effectiveness of water electrolysis, which is applicable to various fields including energy conversion, biotechnology, and magnetohydrodynamic thruster used in seawater.

scholarly journals The Effect of Magnetic Field on the Dynamics of Gas Bubbles in Water Electrolysis

2021 ◽  
Author(s):  
Yan-Hom Li ◽  
Yen-Ju Chen
Keyword(s):  
Magnetic Field ◽  
Buoyancy Force ◽  
Gas Bubbles ◽  
Water Electrolysis ◽  
Platinum Electrodes ◽  
Optimal Layout ◽  
Parallel Magnetic Field ◽  
Hydrogen Bubbles ◽  
The Magnetic Field ◽  
Sluggish Flow

Abstract In this work, the movement of the gas bubbles evolved from the platinum electrodes in the influence of various magnetic field configurations are experimentally investigated. The oxygen and hydrogen bubbles respectively evolve from the surface of anode and cathode have distinctive behaviors in the presence of magnetic fields due to their paramagnetic and diamagnetic characteristics. The magnetic field perpendicular to the surface of the horizontal electrode induces the revolution of the bubbles. The opposite revolution direction between the oxygen and hydrogen bubbles cause the swirling of the flow and spread out the bubbles between the electrode which enhances the conductivity and electrolysis effectiveness. On the other hand, the vertical electrodes in the influence of a parallel magnetic field induce horizontal Lorentz force which effectively spells out the bubbles and increases the conductivity and electrolysis effectiveness as well. However, when the layouts of the electrode and magnetic field result in upward or downward Lorentz forces which competes with the buoyancy force, the sluggish flow in the duct would hinder the movement of the bubbles and decrease the conductivity and charging performance. This phenomenon affects the corresponding natural convection and mass transport as well. These results propose the optimal layout of the electrode and magnetic field which is useful to enhance the conductivity or the effectiveness in water electrolysis.

Effect of a static magnetic field onEscherichia coliadhesion and orientation

2016 ◽  
Vol 62 (11) ◽  
pp. 944-952 ◽  
Author(s):  
Lotfi Mhamdi ◽  
Nejib Mhamdi ◽  
Naceur Mhamdi ◽  
Philippe Lejeune ◽  
Nicole Jaffrezic ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Bacterial Adhesion ◽  
Parallel Magnetic Field ◽  
Field Orientation ◽  
Static Magnetic Fields ◽  
Preliminary Study ◽  
The Difference ◽  
The Magnetic Field

This preliminary study focused on the effect of exposure to 0.5 T static magnetic fields on Escherichia coli adhesion and orientation. We investigated the difference in bacterial adhesion on the surface of glass and indium tin oxide-coated glass when exposed to a magnetic field either perpendicular or parallel to the adhesion surface (vectors of magnetic induction are perpendicular or parallel to the adhesion surface, respectively). Control cultures were simultaneously grown under identical conditions but without exposure to the magnetic field. We observed a decrease in cell adhesion after exposure to the magnetic field. Orientation of bacteria cells was affected after exposure to a parallel magnetic field. On the other hand, no effect on the orientation of bacteria cells was observed after exposure to a perpendicular magnetic field.

Swirling Flow of Magnetic Fluid in Multi-Pole Rotating Magnetic Field

2003 ◽  
Author(s):  
Kenichi Kamioka ◽  
Ryuichiro Yamane
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Circular Cylinder ◽  
Phase Velocity ◽  
Magnetic Fluid ◽  
Swirling Flow ◽  
Peak Velocity ◽  
Rotating Magnetic Field ◽  
Outer Periphery ◽  
The Magnetic Field

The experiments are conducted on the magnetic fluid flow induced by the multi-pole rotating magnetic field in a circular cylinder. The numbers of poles are two, four, six, eight and twelve. The applied electric current and frequency are 2∼6 A and 20∼60 Hz, respectively. The peak velocity of the flow increases with the increase in the strength and the phase velocity of the magnetic field. As the increase in the number of poles, the flow shifts to the outer periphery.

scholarly journals Hierarchical structure of the interstellar molecular clouds and star formation

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Alexander E. Dudorov ◽  
Sergey A. Khaibrakhmanov
Keyword(s):  
Magnetic Field ◽  
Molecular Clouds ◽  
Hierarchical Structures ◽  
Mhd Turbulence ◽  
Parallel Magnetic Field ◽  
Density Profiles ◽  
Statistical Correlations ◽  
Cloud Cores ◽  
Interstellar Molecular Clouds ◽  
The Magnetic Field

AbstractProperties of the hierarchical structures of interstellar molecular clouds are discussed. Particular attention is paid to the statistical correlations between velocity dispersion and size, and between the magnetic field strength and gas density. We investigate the formation of some hierarchical structures with the help of numerical MHD simulations using the ENLIL code. The simulations show that the interstellar molecular filaments with parallel magnetic field and molecular cores can form via the collapse and fragmentation of cylindrical molecular clouds. The parallelmagnetic field halts the radial collapse of the cylindrical cloud maintaining its nearly constant radius ~0.1 pc. The observed filaments with perpendicularmagnetic field can form as a result of themagnetostatic contraction of oblate molecular clouds under the action of Alfvén and MHD turbulence. The theoretical density profiles are fitted with the Plummer-like function and agree with observed profiles of the filaments in Gould’s Belt. The characteristics of molecular cloud cores found in our simulations are in agreement with observations.

On the stability of parallel flows with parallel magnetic fields

1966 ◽  
Vol 293 (1434) ◽  
pp. 342-358 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Parallel Magnetic Field ◽  
Parallel Flows ◽  
The Mean ◽  
The Stability ◽  
The Magnetic Field ◽  
Parallel Magnetic Fields

The first part of the paper is a physical discussion of the way in which a magnetic field affects the stability of a fluid in motion. Particular emphasis is given to how the magnetic field affects the interaction of the disturbance with the mean motion. The second part is an analysis of the stability of plane parallel flows of fluids with finite viscosity and conductivity under the action of uniform parallel magnetic fields. We show that, in general, three-dimensional disturbances are the most unstable, thus disagreeing with the conclusion of Michael (1953) and Stuart (1954). We show how results obtained for two-dimensional disturbances can be used to calculate the most unstable three-dimensional disturbances and thence we prove that a parallel magnetic field can never completely stabilize a parallel flow.

On the effect of a central vortex on a stretched magnetic flux tube

1997 ◽  
Vol 339 ◽  
pp. 121-142 ◽  
Author(s):  
KONRAD BAJER ◽  
H. K. MOFFATT
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Tube ◽  
Swirling Flow ◽  
Magnetic Flux Tube ◽  
Mhd Turbulence ◽  
Elliptical Cross ◽  
Central Vortex ◽  
Principal Axes ◽  
The Magnetic Field

Experiments and numerical simulations of fully developed turbulence reveal the existence of elongated vortices whose length is of the order of the integral scale of turbulence while the diameter is somewhere between the Kolmogorov scale and the Taylor microscale. These vortices are embedded in quasi-irrotational background flow whose straining action counteracts viscous decay and determines their cross-sectional shape. In the present paper we analyse the effect of a stretched vortex of this kind on a uni-directional magnetic flux tube aligned with vorticity in an electrically conducting fluid. When the magnetic Prandtl number is large, Pm[gsim ]1, the field is concentrated in a flux tube which, like the vortex itself, has elliptical cross-section inclined at 45° to the principal axes of strain. We focus on the limit Pm[Lt ]1 when the magnetic flux tube has radial extent much larger than that of the vortex, which appears like a point vortex as regards its action on the flux tube. We find the steady-state solution valid in the entire plane outside the vortex core. The solution shows that the magnetic field has a logarithmic spiral component and no definite orientation of the inner contours. Such magnetized vortices may be expected to exist in MHD turbulence with weak magnetic field where the field shows a tendency to align itself with vorticity. Magnetized vortices may also be expected to exist on the solar surface near the corners of convection cells where downwelling swirling flow tends to concentrate the magnetic field.

Abrikosov Monopole Vortices and Their Images in a Circular Josephson Tunnel Junction

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1265-1270 ◽  
Author(s):  
M. P. Lisitskii ◽  
R. Cristiano ◽  
C. Nappi ◽  
E. Esposito ◽  
L. Frunzio ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Critical Current ◽  
Tunnel Junction ◽  
Perpendicular Magnetic Field ◽  
Simulation Data ◽  
Parallel Magnetic Field ◽  
Josephson Tunnel ◽  
The Magnetic Field ◽  
Good Agreement

We present the results of a numerical simulation of the dependence of the Josephson critical current on the parallel magnetic field in the presence of a large number of Abrikosov 'monopole' vortices for the case of a circular junction. The influence of the junction edge on the distribution of the magnetic field of each vortex was taken into account by introducing image monopole vortices. Our simulations show that the dependence of the Josephson critical current on the parallel magnetic field (the Ic vs Hpar dependence) critically depends on the existence of a vortex located near the center of the junction. The simulation data are compared with experiments made on circular Nb/Al-AlOx/Nb junctions. A good agreement has been found between calculated and Ic vs Hpar dependences measured after the application of a perpendicular magnetic field.

scholarly journals Magnetic Fields in AGN

1998 ◽  
Vol 164 ◽  
pp. 97-103 ◽  
Author(s):  
J. F. C. Wardle
Keyword(s):  
Magnetic Field ◽  
High Redshift ◽  
Parallel Magnetic Field ◽  
Field Orientation ◽  
Future Directions ◽  
Line Region ◽  
Rotation Measure ◽  
Narrow Line Region ◽  
First Time ◽  
The Magnetic Field

AbstractWe review VLBI polarization results. In particular, we discuss the a) “shock in jet paradigm”, b) the orientation of the magnetic field in jets as a function of optical identification, c) rotation measure and Faraday dispersion measurements as a probe of the narrow line region, and d) future directions of polarization observations. Results we emphasize are i) there is still a strong correlation between optical L/C ratio or EW and magnetic field orientation in the jets of blazars, even for high redshift weak-lined objects, ii) observed rotation measures are much smaller than expected from the properties of the NLR, except for some CSS sources. Also iii) a faint boundary layer or sheath (with a parallel magnetic field) has been observed around the jet of the weak-lined blazar 1055+018, and iv) circular polarization has been detected for the first time in the jets of 3C 84 and 3C 279.

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