scholarly journals Correlation Between the Electric Current Generated by a Bean Root Growing in Water and the Rate of Elongation of the Root

1955 ◽  
Vol 8 (1) ◽  
pp. 36 ◽  
Author(s):  
BIH Scott AL Mcaulay ◽  
Pauline Jeyes
Keyword(s):  
Electric Current ◽  
Electric Fields ◽  
Bean Root ◽  
Methods Of Measurement

Methods of measurement of the electric fields produced by plants have been developed which eliminate artefacts commonly present in such investigations.

Flow of Electrolyte With a Surface-Charged Particle in a Nano-Channel: Quasi-Steady Modeling

2009 ◽  
Author(s):  
Z.-P. Qin ◽  
Y.-S. Wang ◽  
G.-X. Wang
Keyword(s):  
Charged Particle ◽  
Electric Current ◽  
Electric Fields ◽  
Planck Equation ◽  
Coupled System ◽  
Navier Stokes Equation ◽  
Ion Concentrations ◽  
Small Pore ◽  
Nano Channel ◽  
Current Change

A Resistive Pulse Sensor (RPS) is a device for counting and characterizing small particles by recording the electrical current change (negative pulse) during the translocation of the particle through a small pore. RPS is now widely used to characterize various micro/nano size particles, including bio-particles, proteins, and DNA. This paper presents a comprehensive multi-physical model of RPS. The model involves a coupled system of the Navier-Stokes equation for flow field, the Nernst-Planck equation for electrolyte ion concentrations, and the Poisson equation for electrical field. The model is used to simulate the quasi-steady flow of electrolyte with a fixed surface charged particle in a micro/nano-channel connecting two reservoirs. The channel and reservoir are assumed to be cylindrical and a 2-D axial-symmetry system is used. The model predicts the flow and electric fields as well as the distribution of the ion concentrations in the channel. The effects of Electrical Double Layer (EDL) on the electric current change through the channel are then investigated. Conditions for the electric current change (positive and negative pulses) are then identified.

scholarly journals Time development of electric fields and currents in space plasmas

2006 ◽  
Vol 24 (3) ◽  
pp. 1137-1143
Author(s):  
A. T. Y. Lui
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Electric Fields ◽  
Time Development ◽  
Space Plasmas ◽  
Simplifying Assumptions ◽  
Electric Fields And Currents ◽  
Definition Of ◽  
The Magnetic Field ◽  
Made In

Abstract. Two different approaches, referred to as Bu and Ej, can be used to examine the time development of electric fields and currents in space plasmas based on the fundamental laws of physics. From the Bu approach, the required equation involves the generalized Ohm's law with some simplifying assumptions. From the Ej approach, the required equation can be derived from the equation of particle motion, coupled self-consistently with Maxwell's equation, and the definition of electric current density. Recently, some strong statements against the Ej approach have been made. In this paper, we evaluate these statements by discussing (1) some limitations of the Bu approach in solving the time development of electric fields and currents, (2) the procedure in calculating self-consistently the time development of the electric current in space plasmas without taking the curl of the magnetic field in some cases, and (3) the dependency of the time development of magnetic field on electric current. It is concluded that the Ej approach can be useful to understand some magnetospheric problems. In particular, statements about the change of electric current are valid theoretical explanations of change in magnetic field during substorms.

scholarly journals Energy distribution and stability of electrons in electric fields

1947 ◽  
Vol 188 (1015) ◽  
pp. 532-541 ◽  
Keyword(s):  
External Field ◽  
Energy Distribution ◽  
Electric Current ◽  
Electric Fields ◽  
Stationary State ◽  
Usual Method ◽  
Lattice Vibrations ◽  
Ionic Crystals ◽  
Free Electrons ◽  
Stationary Conditions

The behaviour of free electrons in ionic crystals in the presence of an external field is studied. It is shown that the usual method of calculating the electric current is incorrect. The correct solution shows that—on the usual assumption that electrons are scattered by the lattice vibrations only—a stationary state is impossible. Stationary conditions can probably be obtained by considering collisions between electrons as well. For very small electron density, however, these latter collisions are negligible. It is shown that in this case the possibility of reaching stationary conditions depends on the behaviour of electrons whose energy is large enough to ionize or excite ions of the lattice.

Electric currents in the ionosphere - Ionization drift due to winds and electric fields

1953 ◽  
Vol 246 (913) ◽  
pp. 306-320 ◽  
Keyword(s):  
Electric Field ◽  
Electric Current ◽  
Electric Fields ◽  
Body Force ◽  
Surrounding Medium ◽  
The Other ◽  
Electric Currents ◽  
Vertical Drift ◽  
Meteor Trails ◽  
Current Flows

An analysis is made of the drift velocity of the (neutral) ionization in a uniform ionosphere under the influences of an electric field and/or atmospheric wind. It is shown that this drift of ionization produces the Ampere body force on the medium; the electric current flows perpendicular to the drift. The motion of a cylinder of ionization, of density differing from the surrounding medium, is then studied. It is found that the motion is electrodynamically stable, but unstable hydrodynamically, if Hall conductivity is appreciable. In the latter event there is rapid accretion of (neutral) ionization on one side of the cylinder, depletion on the other. It is suggested that this is the origin of sporadic E ( E 5 )ionization, and is likely to be an important factor in the production of the long-enduring meteor trails detected by radio methods. Formulae are derived for the horizontal and vertical drift of ionization at all latitudes in a thin ionosphere in which vertical electric currents are prohibited by polarization. Graphs are given which permit derivation of the true wind or field in a given region of the ionosphere from experimental observations of the drift velocities.

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