scholarly journals THE RELATION OF THE STABILITY OF PROTOPLASMIC FILMS IN NOCTILUCA TO THE DURATION AND INTENSITY OF AN APPLIED ELECTRIC POTENTIAL

1925 ◽  
Vol 7 (4) ◽  
pp. 461-471 ◽  
Author(s):  
E. J. Lund ◽  
G. A. Logan
Keyword(s):  
Electric Current ◽  
Electric Potential ◽  
Striated Muscle ◽  
Continuous Phase ◽  
Cathode Side ◽  
Applied Current ◽  
Intensity Threshold ◽  
Sufficient Intensity ◽  
The Stability ◽  
Applied Electric Potential

1. The experiments demonstrate that when a constant electric potential of sufficient intensity is applied to Noctiluca, the protoplasmic films which represent a part of the visible continuous phase of the cytoplasm and plasma membrane at the surface of the cell, become unstable and break down, thus releasing the acid contents of one of the internal discontinuous phases present in the cytoplasm of Noctiluca. This process which occurs first at anode then at the cathode side of the cell, appears to be a selective deemulsification or coalescence similar to that at the surface of an emulsion having a viscous continuous phase. 2. The experiments demonstrate that Nernst's equation See PDF for Equation which expresses approximately the relation of duration and intensity of a constant electric current to threshold stimulation of striated muscle, applies equally well to the process of anodal coalescence in Noctiluca. 3. Anodal and cathodal coalescence have different thresholds, due to the fact that the semipermeable plasma film at the surface of the cell is asymmetric with respect to the direction of the applied current. Attention is called to the possible relation between this phenomenon and the conditions occurring at the synapse between neurons. 4. The stability of the protoplasmic films in relation to the applied electric potential is greater in young cells than in old cells, or in other words the threshold intensity of the stimulus is higher for young than for old cells. 5. Attention is called to the occurrence in the same cell of different receptor-affector mechanisms having a corresponding difference in intensity threshold when an electric current is acting as a stimulus.

Oxygen Exchange in La0.6Sr0.4Co0.2Fe0.8O3−δThin-Film Heterostructures under Applied Electric Potential

2015 ◽  
Vol 119 (34) ◽  
pp. 19915-19921 ◽  
Author(s):  
E. Mitchell Hopper ◽  
Edith Perret ◽  
Brian J. Ingram ◽  
Hoydoo You ◽  
Kee-Chul Chang ◽  
...  
Keyword(s):  
Electric Potential ◽  
Oxygen Exchange ◽  
Applied Electric Potential

Stability of the Base Flow to Axisymmetric and Plane-Polar Disturbances in an Electrically Driven Flow Between Infinitely-Long, Concentric Cylinders

2000 ◽  
Vol 123 (1) ◽  
pp. 31-42
Author(s):  
J. Liu ◽  
G. Talmage ◽  
J. S. Walker
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Axial Magnetic Field ◽  
Normal Modes ◽  
Azimuthal Velocity ◽  
Base Flow ◽  
Transition To Turbulence ◽  
Electrically Conducting ◽  
Concentric Cylinders ◽  
The Stability

The method of normal modes is used to examine the stability of an azimuthal base flow to both axisymmetric and plane-polar disturbances for an electrically conducting fluid confined between stationary, concentric, infinitely-long cylinders. An electric potential difference exists between the two cylinder walls and drives a radial electric current. Without a magnetic field, this flow remains stationary. However, if an axial magnetic field is applied, then the interaction between the radial electric current and the magnetic field gives rise to an azimuthal electromagnetic body force which drives an azimuthal velocity. Infinitesimal axisymmetric disturbances lead to an instability in the base flow. Infinitesimal plane-polar disturbances do not appear to destabilize the base flow until shear-flow transition to turbulence.

ELECTRIC POTENTIAL NEAR A SPHERICAL BODY IN A CONDUCTING HALF‐SPACE

Geophysics ◽  
1971 ◽  
Vol 36 (4) ◽  
pp. 763-767 ◽  
Author(s):  
David B. Large
Keyword(s):  
Point Source ◽  
Electric Current ◽  
Half Space ◽  
Electric Potential ◽  
Spherical Body ◽  
Classical Potential

An extensive summary of classical potential solutions has been given recently by Van Nostrand and Cook (1966). This note presents a solution for the potential due to a point source of electric current placed on the earth’s surface in the vicinity of a buried spherical body of arbitrary resistivity. The analysis follows the procedure suggested by Van Nostrand and Cook and is similar to that used recently by Merkel (1969, 1971).

The Stability of Abiarana Gutta-Percha Latex

1937 ◽  
Vol 10 (2) ◽  
pp. 272-278
Author(s):  
F. K. Daniel ◽  
H. Freundlich ◽  
K. Söllner
Keyword(s):  
Molecular Weight ◽  
Electric Current ◽  
Chemical Nature ◽  
Electrical Charge ◽  
Gutta Percha ◽  
Large Molecular Weight ◽  
Time Average ◽  
The Difference ◽  
The Stability ◽  
Average Size

Abstract 1. The latex of Abiarana gutta-percha is more stable than that of Hevea. In the absence of preservatives Abiarana latex is stable for many months, while Hevea coagulates readily in a few hours. On addition of electrolytes, Abiarana only creams up and is readily and reversibly redispersed; Hevea is coagulated jrreversibly. Under the influence of the electric current Abiarana does not form a coherent skin on the anode; Hevea does so easily. 2. The stability of Abiarana latex is due to a protecting substance reversibly adsorbed on the particles. This substance may be removed by allowing the particles to cream-up repeatedly and by separating the serum from the particles. The serum of Abiarana (or the whole latex) added to Hevea latex strongly protects the latter and causes it to behave like Abiarana latex. 3. A similar protecting action in small concentrations cannot be produced by substances such as gelatin, peptones, lysalbinic acid, starch, etc. The chemical nature of the protecting substance could not be identified. It must have a large molecular weight, since it does not diffuse through membranes. 4. The reversible creaming-up of Abiarana latex is influenced by the cations of the electrolytes added according to their valency, in agreement with the fact that the particles are negatively charged. H+-ion and ter- and tetravalent cations are able to reverse the electrical charge of the particles. 5. The difference in creaming velocity due to different electrolyte concentrations (i. e., to different degree of discharge) seems to depend on time average size and number of aggregates of particles which are formed.

Computation of stability regions for the cylindrical ion trap with no octupole electric field as compared to the corresponding results of the Paul trap

2017 ◽  
Vol 23 (5) ◽  
pp. 272-279
Author(s):  
Houshyar Noshad ◽  
Majid Amouhashemi
Keyword(s):  
Electric Field ◽  
Electric Potential ◽  
Ion Trap ◽  
Paul Trap ◽  
Height Ratio ◽  
Stability Regions ◽  
Stability Diagrams ◽  
Quadrupole Component ◽  
Cylindrical Ion Trap ◽  
The Stability

The cylindrical ion trap is analyzed so that the octupole component of the electric field inside the trap is set to zero. As a consequence, the diameter to height ratio is computed to be 1.20 for which the quadrupole component of the cylindrical ion trap is dominant. Afterwards, it is concluded that the electric potential inside the trap as well as the corresponding stability regions are very similar to those obtained for an ideal Paul trap with pure quadrupole electric field. Furthermore, we drew a conclusion that the stability diagrams of the cylindrical ion trap without octupole term and the stability diagrams of the Paul trap have 5.6%, 3.7%, and 2.9% discrepancy for the first, second, and third stability diagrams, respectively. It should be noted that, expansion of the electric potential inside the cylindrical ion trap in terms of the multipole electric field components and making the advantages of the octupole term elimination has not been reported in the literature previously.

An Erda Study on Proton Migration Induced by Electric Potential in SrZrO3,SrCeO3 and BaCeO3 Oxides:Measurements of Proton Transport Number and Proton Diffusivity

1998 ◽  
Vol 513 ◽  
Author(s):  
A. Kunimatsu ◽  
T. Arai ◽  
K. Takahiro ◽  
S. Nagata ◽  
S. Yamaguchi ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Cathode Material ◽  
Electric Potential ◽  
Proton Transport ◽  
Transport Number ◽  
Proton Concentration ◽  
Good Ability ◽  
Proton Migration ◽  
Dc Current ◽  
Applied Electric Potential

ABSTRACTMigration of protons dissolved in acceptor doped SrZrO3, SrCeO3 and BaCeO3 oxides has been examined under an applied electric potential over a range of temperature from 25 to 220°C. Protons which dissolved in these oxides migrated to the cathode, and they were trapped there when the cathode material had a good ability to getter the migrating hydrogen. The amount of hydrogen accumulated in the cathode could be measured by the ERDA method using a highenergy 4He beam. We measured the amount of hydrogen in the cathode while monitoring the dc current passed through the oxide specimen. The proton transport number was determined from the ratio of the number of hydrogen in the cathode to the total numbers of charge through the specimen. The diffusion coefficient of proton was evaluated using the proton transport number and proton concentration in the specimen.

Electrokinetic Transport in Micro-Nanofluidic Systems With Sudden-Expansion and Contraction Cross Sections

2009 ◽  
Author(s):  
Reiyu Chein ◽  
Baogan Chung
Keyword(s):  
Cross Sections ◽  
Electric Potential ◽  
Vortex Flow ◽  
Stokes Equations ◽  
Limiting Current ◽  
Sudden Expansion ◽  
Positive Pressure ◽  
Electrokinetic Transport ◽  
Nanofluidic System ◽  
Applied Electric Potential

In this study, electrokinetic transport in a micro-nanofluidic system is numerically investigated by solving the transient Poisson, Nernst-Planck, and Navier-Stokes equations simultaneously. The system considered is a nanochannel connected with two microchannels at its ends. Under various applied electric potential biases, the effect of concentration polarization on the fluid flow, induced pressure and electric current is examined. By comparing with the Donnan equilibrium condition and electroosmotic flow in microscale dimension, electric body force due to non-zero charge density is the mechanism for producing vortex flow and inducing positive pressure gradient in the anodic side of the system. The diffusive boundary layer thickness is reduced due to the stirring of the generated vortex flow and results in the over-limiting current when the applied electric potential bias is high.

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