Electrode designation, representation

Fig. 6.2 Working electrode design with 25 jun metallic wires. Top schematic representation (a) Printed board carrier, (b) heated wire, (c) copper leads,...

Fig. 3. Schematic representation of the principle of design and operation of a consumble-electrode furnace for melting steels in a vacuum (1).

Cell geometry, such as tab/terminal positioning and battery configuration, strongly influence primary current distribution. The monopolar constmction is most common. Several electrodes of the same polarity may be connected in parallel to increase capacity. The current production concentrates near the tab connections unless special care is exercised in designing the current collector. Bipolar constmction, wherein the terminal or collector of one cell serves as the anode and cathode of the next cell in pile formation, leads to gready improved uniformity of current distribution. Several representations are available to calculate the current distribution across the geometric electrode surface (46—50). 

The principle of the measurement is described with the help of Fig. 2-7 [50]. Potential measurement is not appropriate in pipelines due to defective connections or too distant connections and low accuracy. Measurements of potential difference are more effective. Figure 3-24 contains information on the details in the neighborhood of a local anode the positions of the cathodes and reference electrodes (Fig. 3-24a), a schematic representation of the potential variation (Fig. 3-24b), and the derived values (Fig. 3-24c). Figure 2-8 should be referred to in case of possible difficulties in interpreting the potential distribution and sign. The electrical potentials of the pipeline and the reference electrodes are designated by... 

Figure 2.39 (a) Schematic representation of the experimental arrangement for attenuated total reflection of infrared radiation in an electrochemical cell, (b) Schematic representation of the ATR cell design commonly employed in in situ 1R ATR experiments. SS = stainless steel cell body, usually coated with teflon P — Ge or Si prism WE = working electrode, evaporated or sputtered onto prism CE = platinum counter electrode RE = reference electrode T = teflon or viton O ring seals E = electrolyte. 

Figure 2.40 Schematic representation of the external reflectance cell design commonly employed in in situ IR experiments, if the working electrode is a semiconductor, then the semiconductor/ electrolyte interface can be studied under illumination with, for example, UV light by directing the beam perpendicular to the IR beam, as shown.

The other popular approach to in situ spectroelectrochemistry is based on the use of an OTE electrode in a thin-layer, optically transparent thin layer electrode (OTTLE), cell. A schematic representation of one design of OTTLE cell is shown in Figure 2.105. 

Figure 16.9—Representation of a quadrupole. Notice the pairing of oppositely charged electrodes. This experimental design requires high-precision machining of the hyperbolic electrodes. To the right a series of equipotential hyperbolic lines in the central part of the quadrupole is shown.

A schematic representation of the electrode-electrolyte interface is given as Figure 7.10, where the block used to represent the local Ohmic impedance reflects the complex character of the Ohmic contribution to the local impedance response. The impedance definitions presented in Table 7.2 were proposed by Huang et al. ° for local impedance variables. These differ in the potential and current used to calculate the impedance. To avoid confusion with local impedance values, the symbol y is used to designate the axial position in cylindrical coordinates. 

To introduce the concept and design details, a schematic representation of the 1x4 microfluidic switch with one inlet port and four outlet ports as shown in Fig. 1 is taken as a case study here. This case-study device, as shown in Fig. 1, consists of an embedded heater, a capillary system with hydrophilic microchannels, and a specific arrangement of hydrophobic patches. This device could be expanded to 1 xN microfluidic switch via the similar design. Also the embedded heater could be replaced by electrolysis electrodes. In Fig. 1, Li represents the length of each hydrophobic patch in the microchannel /. From microchannel 1 to 4, Li decreases with an increase of patch number in each microchannel. For the device design shown in Fig. 1, there are 1, 2, 3, and 4 separated hydrophobic patches in microchannel 1, 2, 3, and 4, respectively. These distributed patches have the same length in each microchannel. 

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