Ring-shaped electrodes

Circle-Shaped Electrode Ring-Shaped Electrode... 

The external heating boxes for the caustic soda evaporator with forced circulation must be anodically protected separately. Ring-shaped impressed current electrodes of carbon steel are mounted and insulated on supporting brackets (see Fig, 21-12). 

A special O-ring cell design is needed for in situ infrared (IR) vibrational characterization of an electrochemical interface. The absorption of one monolayer (i.e. <1015 cm 2 vibrators) can be measured if the silicon electrode is shaped as an attenuated total reflection (ATR) prism, which allows for working in a multiple-in-ternal-reflection geometry. A set-up as shown in Fig. 1.9 enhances the vibrational signal proportional to the number of reflections and restricts the equivalent path in the electrolyte to a value close to the product of the number of reflections by the penetration depth of the IR radiation in the electrolyte, which is typically a tenth of the wavelength. The best compromise in terms of sensitivity often leads to about ten reflections [Oz2]. 

In a series of papers Jaeger, Hudson and coworkers investigated how the spatio-temporal behavior is affected by different model parameters, such as reaction rate, electrode capacitance, the geometry of the WE and the relative positions of all three electrodes, WE, CE and RE in the simplified N-NDR model for electrodissolution reactions [27-29]. Below, we discuss a few examples taken from these works. For a geometry similar to the one discussed above, i.e. with ring-shaped working and... 

Figure 14.27 The effect of W/FM on the width of the ring-shaped polymer deposition area on copper electrodes observed in methane plasmas with various magnetic field strengths.

In 1969, Wipf and Simon reported an outstanding potassium ionophore, valinomycin. Valinomycin is an example of a mobile ion carrier. It is a ring-shaped polypeptide that increases the permeability of a membrane to K . The ring has a hydrophobic exterior, made up of valine side chains, and a polar interior, where a single K can fit precisely (see Figure 8.30). In the electrode process, valinomycin transports potassium ions across the membrane by picking up on the solution side of the membrane and releasing it at the transducer surface. 

Figure 11.2.3 Potential distribution in mV at surface of ring-shaped mercury pool electrode using an unsymmetrical auxiliary electrode. Solution 0.5 M H2SO4 total cell current 40 mA pool 1.5 in. o.d., 1.0 in. i.d. Small circle shows position of the auxiliary electrode s fritted-glass separator, situated 4 mm above the pool surface. [Reprinted with permission from G. L. Booman and W. B. Holbrook, Anal. Chem., 35, 1793 (1963). Copyright 1963, American Chemical Society.]...

Ring shaped glow discharge cathode and electrodes for the spiral shaped Al-evaporators mounted at the top of the metallizing plant. 

The RFS method makes use of the fact that carbon disc electrodes used in RDE spectrometers are porous and can be used as a filter to trap particles in oil samples. Early versions of the RFS fixture used standard disc electrodes with some success and acceptable sensitivity [5]. However, standard disc electrode geometry caused the process to be slow, and lack of manufacturing control of disc porosity resulted in poor repeatability. Due to its ease of use and inherent advantages, the RFS concept was recently revisited with the intent of further improving performance. The updated RFS technique uses custom ring-shaped graphite electrodes and a semi-automatic process to improve sensitivity and repeatability and to reduce sample preparation time. 

Indirect bipolar (IB) polarization of the catalyst film in a ring-shaped electrochemical cell is realized by using the two gold electrodes as feeder electrodes. For advanced characterization of the cell, a third electric connection may be added. This latter, connected to the catalyst film itself, permits measurements also in the direct (monopolar) polarization mode, which is useful for the determination of the current bypass. 

Figure 30. Current-potential curves of a ring-shaped Rh/YSZ cell at different polarization modes. O direct cathodic (DC) A direct anodic (DA) O DC + DA indirect bipolar (IB). I4eii. cell potential between the two feeder electrodes. Feed composition C3H6 NO/75 500 Pa, T= 375°C.

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