Electrode pair

In practice, elimination of axial current flow requires relatively fine segmentation, eg, 1—2 cm, between electrodes, which means that a utihty-sized generator contains several hundred electrode pairs. Thus, one of the costs paid for the increased performance is the larger number of components and increased mechanical complexity compared to the two-terrninal Faraday generator. Another cost is incurred by the increased complexity of power collection, in that outputs from several hundred terminals at different potentials must be consoHdated into one set of terminals, either at an inverter or at the power grid. 

Another configuration having power collection from only two terminals is the Hall generator shown in Figure 5d. In this configuration, opposing electrode pairs are connected, and the current flow for power extraction is axial. E = 0, and... 

For current consoHdation, the basic circuits, used at each of the multiple power take-off points, are stacked into a Christmas tree topology to form a single power take-off terminal pair. Scale-up of these devices to commercial sizes is not expected to be a problem, as standard electrical components are available for all sizes considered. A different type of consoHdation scheme developed (117), uses dc to ac converters to connect the individual electrodes to the consoHdation point. The current from each electrode can be individually controUed by the converter, which can either absorb energy from or deHver energy to the path between the electrode and the consoHdation point. This scheme offers the potential capabiHty of controlling the current level of each electrode pair. 

As indicator electrodes glass and antimony electrodes are commonly used, but it must be noted that in benzene-methanol solutions, a glass-antimony electrode pair may be used in which the glass electrode functions as reference electrode. Glass electrodes should not be maintained in non-aqueous solvents for long periods, as the hydration layer of the glass bulb may be impaired and the electrode will then cease to function satisfactorily. 

Logarithmic scale for expressing acidity or alkalinity of water (7.0 to 0 indicates increasing acidity 7.0 to 14 indicates increasing alkalinity). Measured by means of a glass electrode/reference electrode pair immersed in the water sample under test. The potential difference depends upon the pH which is then displayed on a pH meter (high input impedance, millivoltmeter). 

In the salt injection method(3l) a pulse of salt solution is injected into the line and the time is measured for it to travel between two electrode pairs situated a known distance apart, downstream from the injection point. 

In a recent study of the transport of coarse solids in a horizontal pipeline of 38 mrrt diameter, pressure drop, as a function not only of mixture velocity (determined by an electromagnetic flowmeter) but also of in-line concentration of solids and liquid velocity. The solids concentration was determined using a y-ray absorption technique, which depends on the difference in the attenuation of y-rays by solid and liquid. The liquid velocity was determined by a sail injection method,1"1 in which a pulse of salt solution was injected into the flowing mixture, and the time taken for the pulse to travel between two electrode pairs a fixed distance apart was measured, It was then possible, using equation 5.17, to calculate the relative velocity of the liquid to the solids. This relative velocity was found to increase with particle size and to be of the same order as the terminal falling velocity of the particles in the liquid. 

Ben Yaakov and Lorch [8] identified the possible error sources encountered during an alkalinity determination in brines by a Gran-type titration and determined the possible effects of these errors on the accuracy of the measured alkalinity. Special attention was paid to errors due to possible non-ideal behaviour of the glass-reference electrode pair in brine. The conclusions of the theoretical error analysis were then used to develop a titration procedure and an associated algorithm which may simplify alkalinity determination in highly saline solutions by overcoming problems due to non-ideal behaviour and instability of commercial pH electrodes. 

The concentration of gases such as C02, NH3, S02 andN02 in aqueous solutions can be measured with an electrode consisting of a glass electrode/reference electrode pair inside a plastic tube which is sealed with a thin gas-permeable membrane and containing an appropriate electrolyte solution (Figure 6.5). 

The above change in pH is instantly detected by means of a Ag/AgCl reference electrode pair (E) dipped in the film of internal solution as shown in Figure 16.8. 

Description Power (kW) Operating Pressure (psig) Material Electrode Pairs/ Cell Stack In Service Installed Standby In Storage... 

An alternative and more recent electroanalytical tool is square-wave voltammetry (which is probably now employed more often than normal or differential pulse voltammetry). In this technique, a potential waveform (see Figure 6.26) is applied to the working electrode. Pairs of current measurements are then made (depicted on the figure as t and f2) these measurements are made for each wave period ( cycle ), which is why they are drawn as times after to (when the cycle started). The current associated with the forward part of the pulse is called /forward, while the current associated with the reverse part is /reverse- A square-wave voltammogram is then just a graph of the difference between these two... 

ISOTRON Corporation s electrokinetic decontamination process is a patented, in situ process for the removal of contaminants from soil, groundwater, and porous concrete. The technology applies a low-intensity direct current (DC) across electrode pairs to facilitate electromigration and electro-osmosis of contaminants. The process works primarily on highly soluble ionized inorganics including alkah metals, chlorides, nitrates, and phosphates. Heavy metals such as lead, mercury, cadmium, and chromium have also responded favorably. 

The magnetically induced electric field falls off much less rapidly with distance than the fields from the surface electrodes, thus enabling structures at greater depths to be stimulated without the high fields at the surface that stimulate pain fibers. For example, relative to the surface field, the magnetically induced electric field at a depth of 40 mm will be approximately 10 times greater than that produced by the large electrode pair. (Barker 1991)... 

Research began as an investigation of electrically induced ionic adsorption on porous "inert" electrodes. Electrode pairs based on carbon have been developed which will demineralize saline water at low voltage, and can be regenerated upon reversal of polarity. Various carbon electrodes have been conveniently classified into cation- and anion-responsive types. As received carbons are normally cation-responsive, but anion-responsive types have been made by chemical treatment. Laboratory demineralization cells based on this principle have been constructed and operated. Owing primarily to the low cost of basic construction materials, the process shows great promise for the economical conversion of saline waters. 

The basic elements of a new electrochemical approach to saline water demineralization under study at the University of Oklahoma for the past three years are two porous electrodes, one of which is responsive to cations and the other to anions. When an appropriate voltage is applied to such an electrode pair immersed in saline water, cations are removed by the former and anions by the latter. In the regeneration phase, reversal of voltage gives up these ions to a reject solution. 

Atenolol may be assayed in glacial acetic acid/acetic anhydride 15 2 by titration with o.l M perchloric acid. The endpoint may be determined po-tentiometrically using a glass/calomel electrode pair.(5)... 

M 1] [P ly The flow was exposed to three electrode pairs instead of one, as used for all experiments described above [91]. It was shown that a successive progression of the interface deformation and thus of mixing could be achieved in this way. After... 

The method is based on determining the potential difference between an electrode pair, consisting of a glass electrode sensitive to the difference in the hydrogen ion activity in the sample solution and the internal filling solution, and a reference electrode, which is supposed to have a constant potential independent of the immersing solution. 

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