Voltammetry at a Rotating and a Stationary Very Thin Ring Electrode

1988 ◽  
Vol 135 (8) ◽  
pp. 1985-1993 ◽  
Author(s):  
James S. Symanski ◽  
Stanley Bruckenstein
Keyword(s):  
Ring Electrode ◽  
Thin Ring

Fabrication and Characterisation of the First Graphene Ring Micro Electrodes (GRIMEs)

2012 ◽  
Vol 1407 ◽  
Author(s):  
J.W. Dickinson ◽  
F.P.L. Andrieux ◽  
C. Boxall
Keyword(s):  
Redox System ◽  
Dip Coating ◽  
Outer Radius ◽  
Ring Electrode ◽  
High Resistivity ◽  
Current Response ◽  
Fibre Optics ◽  
Thin Ring ◽  
Reduced Graphite Oxide ◽  
Diameter Fibre

ABSTRACTWe report the fabrication and characterisation of the first graphene ring micro electrodes, formed by dip coating fibre optics with subsequently reduced graphite oxide. The behaviour of the so-formed Graphene RIng Micro Electrodes (GRIMEs) is studied using the ferricyanide probe redox system while electrode thicknesses is assessed using established electrochemical methods. A ring electrode of ∼73 nm thickness is produced on 220 μm diameter fibre optics, corresponding to an inner to outer radius ratio of >0.999, so allowing for use of extant analytical descriptions of very thin ring micro electrodes in data analysis. GRIMEs are highly reliable (current response invariant over >3000 scans) with the microring design allowing for efficient use of electrochemically active graphene edge sites. Further, the associated nA scale currents neatly obviate issues relating to the high resistivity of undoped graphene. Thus, the use of graphene in ring micro electrodes improves the reliability of existing micro electrode designs and expands the range of use of graphene-based electrochemical devices.

POTENTIAL DISTRIBUTION DUE TO A CYLINDRICAL ELECTRODE MOUNTED ON AN INSULATING PROBE

Geophysics ◽  
1959 ◽  
Vol 24 (3) ◽  
pp. 566-579 ◽  
Author(s):  
Leendert de Witte ◽  
Roy W. Gould
Keyword(s):  
Linear Equations ◽  
Median Plane ◽  
Delta Function ◽  
Ring Electrode ◽  
Cylindrical Electrode ◽  
Thin Ring ◽  
Electrode Length ◽  
Simultaneous Linear Equations ◽  
Current Ring ◽  
Drill Holes

The potentials around a finite cylindrical electrode can be obtained by dividing the electrodes into rings of equal thickness and substituting an infinitely thin current ring for each of the slices. The field of an infinitely thin ring electrode mounted on an insulating cylindrical probe of the same diameter can be found by combining the properties of the delta function with a solution of Laplace’s equation in cylindrical co‐ordinates. Combination of solutions for the infinitely thin rings under the condition that the potential of the electrode surface be constant leads to a system of simultaneous linear equations. By increasing the number of slices, the potential around the finite electrode can be found arbitrarily close. The problem of a cylindrical electrode on a sonde located coaxially in a conducting hole, drilled through a medium of different conductivity, is treated by the same method. This arrangement is of interest in electrical logging of drill holes. Numerical examples have been calculated on an IBM 650 magnetic drum computer. The potential along the surface of the insulating probe, at distances larger than twice the electrode length, can be approximated with good accuracy by assuming that all of the current is emitted from an infinitely thin ring located in the median plane of the electrode.

Use of Electrochemical Methods for the Study of Mass Transfer and Drag Reduction in Polymer Solutions Close to a Wall

1979 ◽  
Vol 101 (1) ◽  
pp. 121-127 ◽  
Author(s):  
C. Deslouis ◽  
I. Epelboin ◽  
B. Tribollet ◽  
L. Viet
Keyword(s):  
Mass Transfer ◽  
Drag Reduction ◽  
Electrochemical Method ◽  
Friction Velocity ◽  
Rotating Disk ◽  
Ring Electrode ◽  
Transfer Rates ◽  
Thin Ring ◽  
Maximum Drag Reduction ◽  
Drag Reducing Polymer

Mass transfer to the surface of a rotating disk in the presence of a drag reducing polymer (PEO) has been studied by an electrochemical method. Mass transfer rates were predicted and measured for different electrode geometries: (i) thin ring, (ii) circular microelectrode, and (iii) the disk. A relation for friction velocity available up to maximum drag reduction conditions where the average flow is laminarized at the scale of the diffusion layer, has been proposed from the analysis of the experimental data on circular microelectrode and ring electrode. The comparison of these data with disk electrode measurements substantiated a sharp thickening of the diffusion sublayer at the lowest polymer concentrations.

Ultrastructural study on the development of rat amygdaloid body

1990 ◽  
Vol 48 (3) ◽  
pp. 432-433
Author(s):  
A. Manolova ◽  
S. Manolov
Keyword(s):  
Nerve Cells ◽  
Amygdaloid Complex ◽  
Amygdaloid Body ◽  
Thin Ring ◽  
Morphological Criteria ◽  
Neural Processes ◽  
Abundant Cytoplasm ◽  
Level 1 ◽  
Few Data ◽  
Oval Shape

Relatively few data on the development of the amygdaloid complex are available only at the light microscopic level (1-3). The existence of just general morphological criteria requires the performance of other investigations in particular ultrastructural in order to obtain new and more detailed information about the changes in the amygdaloid complex during development.The prenatal and postnatal development of rat amygdaloid complex beginning from the 12th embrionic day (ED) till the 33rd postnatal day (PD) has been studied. During the early stages of neurogenesis (12ED), the nerve cells were observed to be closely packed, small-sized, with oval shape. A thin ring of cytoplasm surrounded their large nuclei, their nucleoli being very active with various size and form (Fig.1). Some cells possessed more abundant cytoplasm. The perikarya were extremely rich in free ribosomes. Single sacs of the rough endoplasmic reticulum and mitochondria were observed among them. The mitochondria were with light matrix and possessed few cristae. Neural processes were viewed to sprout from some nerve cells (Fig.2). Later the nuclei were still comparatively large and with various shape.

Tire Vibrations

1977 ◽  
Vol 5 (4) ◽  
pp. 202-225 ◽  
Author(s):  
G. R. Potts ◽  
C. A. Bell ◽  
L. T. Charek ◽  
T. K. Roy
Keyword(s):  
Natural Frequencies ◽  
Standing Waves ◽  
Resonant Mode ◽  
Mode Shapes ◽  
Resonant Vibrations ◽  
Resonant Frequencies ◽  
Radial Tire ◽  
Analysis Techniques ◽  
Thin Ring ◽  
Good Agreement

Abstract Natural frequencies and vibrating motions are determined in terms of the material and geometric properties of a radial tire modeled as a thin ring on an elastic foundation. Experimental checks of resonant frequencies show good agreement. Forced vibration solutions obtained are shown to consist of a superposition of resonant vibrations, each rotating around the tire at a rate depending on the mode number and the tire rotational speed. Theoretical rolling speeds that are upper bounds at which standing waves occur are determined and checked experimentally. Digital Fourier transform, transfer function, and modal analysis techniques used to determine the resonant mode shapes of a radial tire reveal that antiresonances are the primary transmitters of vibration to the tire axle.

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