Experiments on the stability of a liquid bridge in an axial electric field

1993 ◽  
Vol 5 (4) ◽  
pp. 1081-1083 ◽  
Author(s):  
Subramanian Sankaran ◽  
D. A. Saville
Keyword(s):  
Electric Field ◽  
Liquid Bridge ◽  
Axial Electric Field ◽  
The Stability

Investigation of a Caesium Plasma Diode Using an Electron Beam Probing Technique 1, 2

1967 ◽  
Vol 22 (7) ◽  
pp. 1057-1067 ◽  
Author(s):  
Werner Ott
Keyword(s):  
Electron Beam ◽  
Electric Field ◽  
Charge Carriers ◽  
Axial Electric Field ◽  
Fluorescent Screen ◽  
Plasma Diode ◽  
The Stability ◽  
Ion Emission ◽  
Field Plots ◽  
Ribbon Beam

The plasma in a plane caesium diode with a hot emitter and a cold collector was investigated experimentally with a ribbon-shaped electron beam. The ribbon beam is projected through the diode at an angle of 45 degrees to its axis and allowed to strike a fluorescent screen. Variations in the axial electric field of the diode cause the ribbon beam to be distorted. The image of the distorted beam as seen on the fluorescent screen then constitutes a plot of the axial electric field along the axis of the diode.The field plots so obtained are compared with a theory in which the collisions of the charge carriers are neglected. By means of this comparison it is possible to evaluate the neutralization parameter, the plasma density, and an average drift energy of the charge carriers.The results show that the theory correctly describes the different modes of the potential distribution and especially the transitions between modes of operation as long as the diode is free of oscillations.The stability of the different possible static potential distributions was also investigated. It was found experimentally that the system is unstable if the electron emission is less than the ion emission and the collector potential is positive.

The effect of an axial electric field on the nonlinear stability between two uniform stream flows of finitely conducting cylinders

2003 ◽  
Vol 81 (6) ◽  
pp. 805-821 ◽  
Author(s):  
Abdel Raouf F Elhefnawy ◽  
Galal M Moatimid ◽  
Abd Elmonem Khalil Elcoot
Keyword(s):  
Dispersion Relation ◽  
Electric Field ◽  
Circular Cross Section ◽  
Multiple Scale ◽  
Physical Parameters ◽  
Linear Dispersion ◽  
Order Problem ◽  
Nonlinear Schrödinger ◽  
Axial Electric Field ◽  
The Stability

Weakly nonlinear streaming instability of two conducting fluids with an interface is presented for cylinders of circular cross section. The two fluids are subjected to a uniform axial electric field. Gravitational effects are neglected. The method of multiple scale perturbation is used to obtain a dispersion relation for the first-order problem and two nonlinear Schrödinger equations for the higher orders. The nonlinear Schrödinger equation, generally, describes the competition between nonlinearity and a linear dispersion relation. One of these equations is used to determine the nonlinear cutoff electric field separating stable and unstable disturbances, while the other is used to analyze the stability of the system. The stability criterion is expressed theoretically in terms of various parameters of the problem. Stability diagrams are obtained for different sets of physical parameters. New instability regions in the parameter space, which appear due to nonlinear effects, are indicated. PACS Nos.: 47.20, 47.55.C, 47.65

Linear oscillations and stability of a liquid bridge in an axial electric field

2001 ◽  
Vol 13 (12) ◽  
pp. 3564-3581 ◽  
Author(s):  
N. A. Pelekasis ◽  
K. Economou ◽  
J. A. Tsamopoulos
Keyword(s):  
Electric Field ◽  
Liquid Bridge ◽  
Axial Electric Field

Effects of non-axial electric field gradients on the ferromagnetic state of amorphous rare-earth alloys

1980 ◽  
Vol 58 (5) ◽  
pp. 629-632 ◽  
Author(s):  
H. Hernandez ◽  
R. Ferrer ◽  
M. J. Zuckermann
Keyword(s):  
Rare Earth ◽  
Electric Field ◽  
Ferromagnetic State ◽  
Rare Earth Alloys ◽  
Electric Field Gradients ◽  
Axial Electric Field ◽  
Ferromagnetic Alloys ◽  
Field Gradients ◽  
Ordered State

We discuss the influence of non-axial electric field gradients on the ordered state of amorphous ferromagnetic alloys containing rare-earth atoms.

Directionality and the Role of Polarization in Electric Field Effects on Radical Stability

2017 ◽  
Vol 70 (4) ◽  
pp. 367 ◽  
Author(s):  
Ganna Gryn'ova ◽  
Michelle L. Coote
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Radical Reactions ◽  
Electric Field Effects ◽  
Dissociation Energies ◽  
Barrier Heights ◽  
Diol Dehydratase ◽  
Group A ◽  
Activity Of Enzymes ◽  
The Stability

Accurate quantum-chemical calculations are used to analyze the effects of charges on the kinetics and thermodynamics of radical reactions, with specific attention given to the origin and directionality of the effects. Conventionally, large effects of the charges are expected to occur in systems with pronounced charge-separated resonance contributors. The nature (stabilization or destabilization) and magnitude of these effects thus depend on the orientation of the interacting multipoles. However, we show that a significant component of the stabilizing effects of the external electric field is largely independent of the orientation of external electric field (e.g. a charged functional group, a point charge, or an electrode) and occurs even in the absence of any pre-existing charge separation. This effect arises from polarization of the electron density of the molecule induced by the electric field. This polarization effect is greater for highly delocalized species such as resonance-stabilized radicals and transition states of radical reactions. We show that this effect on the stability of such species is preserved in chemical reaction energies, leading to lower bond-dissociation energies and barrier heights. Finally, our simplified modelling of the diol dehydratase-catalyzed 1,2-hydroxyl shift indicates that such stabilizing polarization is likely to contribute to the catalytic activity of enzymes.

Electrohydrodynamic stability: Taylor–Melcher theory for a liquid bridge suspended in a dielectric gas

2002 ◽  
Vol 452 ◽  
pp. 163-187 ◽  
Author(s):  
C. L. BURCHAM ◽  
D. A. SAVILLE
Keyword(s):  
Surface Tension ◽  
Dielectric Constant ◽  
Electric Fields ◽  
Liquid Bridge ◽  
Numerical Solutions ◽  
Specific Conductivity ◽  
Axisymmetric Deformation ◽  
Aspect Ratios ◽  
The Stability ◽  
Theory And Experiment

A liquid bridge is a column of liquid, pinned at each end. Here we analyse the stability of a bridge pinned between planar electrodes held at different potentials and surrounded by a non-conducting, dielectric gas. In the absence of electric fields, surface tension destabilizes bridges with aspect ratios (length/diameter) greater than π. Here we describe how electrical forces counteract surface tension, using a linearized model. When the liquid is treated as an Ohmic conductor, the specific conductivity level is irrelevant and only the dielectric properties of the bridge and the surrounding gas are involved. Fourier series and a biharmonic, biorthogonal set of Papkovich–Fadle functions are used to formulate an eigenvalue problem. Numerical solutions disclose that the most unstable axisymmetric deformation is antisymmetric with respect to the bridge’s midplane. It is shown that whilst a bridge whose length exceeds its circumference may be unstable, a sufficiently strong axial field provides stability if the dielectric constant of the bridge exceeds that of the surrounding fluid. Conversely, a field destabilizes a bridge whose dielectric constant is lower than that of its surroundings, even when its aspect ratio is less than π. Bridge behaviour is sensitive to the presence of conduction along the surface and much higher fields are required for stability when surface transport is present. The theoretical results are compared with experimental work (Burcham & Saville 2000) that demonstrated how a field stabilizes an otherwise unstable configuration. According to the experiments, the bridge undergoes two asymmetric transitions (cylinder-to-amphora and pinch-off) as the field is reduced. Agreement between theory and experiment for the field strength at the pinch-off transition is excellent, but less so for the change from cylinder to amphora. Using surface conductivity as an adjustable parameter brings theory and experiment into agreement.

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