Electrode immersion depth

Computations of power, temperature and velocity distributions were made for two cases where the electrode immersion depths and currents were varied. In the first case, the three electrodes were immersed in the slag to a uniform depth of260 mm, and the currents were 24.5, 24.7 and 21.7 kA for the electrodes El, E2 and E3, respectively. In the second case, the immersion depth was increased to 540 mm, and the currents were increased to 27.3,29.1 and 25.4 kA for El, E2 and E3, respectively. In order to represent the 3-D effects, the results are shown in two mutually peipendicular planes (1) the longitudinal symmetric plane of the furnace (Plane-I), and (2) a cross-sectional plane (Plane-II) which extends from the symmetric plane to the side wall, intersecting the middle electrode E2 at the centre. 

Figure 8.12. Basic geometty of the four-electrode method with double immersion, a, b, c, d - electrodes, AW- distance in the immersion depth, Vi, V2 - voltage, I, I2- current.

As it follows from Eq. (8.70), only the distance in the electrodes depth of immersion must be known. When the temperature of the measured liquid is changed, the change in the surface level (new depths of immersions) need not be measured. Ohta et al. (1981) also discussed the role of different parameters, i.e. the ratio between the electrode diameter and their distances, the material of the cmcible, electrode displacement from the center of the cmcible, the depth of measured liquid, immersion depth, the frequency of the measuring current, etc. 

FIGURE 4.7 Variation of the c(x)/c(0) ratio with depth for TPY Y in contact with different MeCN electrolytes from chronocoulometric data at sample-modified paraffin-impregnated graphite electrodes immersed into 0.10 M I lex NI I g/Met N (triangles), 0.10 M BU4NPF5/ MeCN (squares), and 0.10 M Et4NPFyMeCN (rhombs). 

Xd is evaluated (the electrode surface is estimated from the measurement of the immersion depth h of the electrode in the electrolyte). 

Figure 4.22 Scheme showing an installation for the preparation of carbon onions in molten alkali halogenide. The kind of carbon material obtained depends on the immersion depth of the graphite electrode. 

One of two platinum electrodes was immersed into an NaCl solution (10 mol/1) to a fixed depth. The immersion depth of the second electrode was a variable factor. Kinetics of the second electrode potential variation towards that of the silver chloride was registered and compared to the case when a PVB powder was placed on the solution surface (dispersion degree 160-200pm, powder layer density 4mg/cm ). 

Application of polymer powders on the solution surface leads to the generation of an electrode potential gradient in solution depth (Fig. 1.9). The strongest reduction of the potential in time was recorded at a minimal (15 mm) distance of the electrode from the powder layer on the surface. With increasing immersion depth, the potential variation becomes less prominent and is not registered at 60 mm depth. 

Fig. 1.9. Dependence of platinum electrode potential (U) in NaCl solution with PVB powder on its surface versus time (t) and immersion depth of the electrode (mm) (1) 15 (2) 30 (3) 45 (4) 60. Polarization current density is - -0.1 mA/cm ...

EGTA. Arrange the two electrodes such that they are at the same height above the base of the beaker and about 0.5 cm apart immersion depth should be 3 to 4 cm. Stir during titration. Immerse the fine tip of the burette, not quite touching the base of the beaker, at the greatest possible... 

Some of the advantages of this type of sensor were already anticipated in one of the earliest FIA applications, namely, the joint determination of sodium and potassium in serum. Important parameter include the angle at which the carrier impinges on the active surface, the electrode placement angle, the immersion depth and surface area, the flow rates, and the cell void volume. 

Cells used are open topped rectangnlar tanks constructed of concrete and lined with PVC. Cell dimensions are dictated by the size of the electrodes, and in particular the anode dimensions. Anodes are generally in the range of 2(X) to 300 kg starting weight with thicknesses of around 30 mm. Immersed depth is commonly about 1.3 times the electrode width, hence the following is typical ... 

The cathodic substrate for recovering pure silicon were more extended surface materials such as nickel plates (50 X10 X1 mm) or others, which will be the subject of discussions below. The surface area of the working electrode was determined after each experiment by measuring the immersion depth in the bath. Anodes were for this purpose, 90 to 100% mass silicon-iron alloys from Goodfellow. 

Proton conductivities of fully hydrated membranes (24 h at ambient temperature in double deionized HjO) may be measured using two- or four-probe electrochemical impedance spectroscopy (EIS) at frequency 0.1-10 MHz with AC amplitude of 5 or 10 mV (Rg. 3.2). For good membrane-electrode contact the PEM is placed between two Hg or Pt electrodes in a sealed conductivity cell, thermostated at the desired T for about 5 h before measurements. It is advisable to perform the measurements with dry membranes from 20 up to 100°C in 10°C steps with wet membranes. Each sample should be measured 10 times and the average value of the impedance, R, used for calculating the proton conductivity o = d/RS (S/cm), where d is the membrane thickness, thus the distance between the electrodes. The results are sensitive to the specimen immersion depth, quality of deionized water, and electrode/membrane contact. Usually, the ionic conductivity correlates with the degree of sulf onation, 38. .82,83... 

Two major sources of ultrasound are employed, namely ultrasonic baths and ultrasonic immersion hom probes [79, 71]- The fonuer consists of fixed-frequency transducers beneath the exterior of the bath unit filled with water in which the electrochemical cell is then fixed. Alternatively, the metal bath is coated and directly employed as electrochemical cell, but m both cases the results strongly depend on the position and design of the set-up. The ultrasonic horn transducer, on the other hand, is a transducer provided with an electrically conducting tip (often Ti6A14V), which is inuuersed in a three-electrode thenuostatted cell to a depth of 1-2 cm directly facing the electrode surface. 

A also depends on the depth of immersion of the electrodes up to a certain value and the electrodes should always be at such a depth that A is independent of it. In most modern instruments either the electrodes are constructed to have >4 = 1 cm or there is a facility for compensating for values of A other than 1 cm. For accurate work the cell constant is usually measured for each set of electrodes by a standard method (Lind, Zwolenik and Fuoss, 1959). 

For chemically reactive metals such as Fe, Ni, Mo and W, etc., tip polishing is in general very simple. As shown in Fig. 3.5, a beaker is filled with three quarters of the recommended polishing solution. A piece of thin wire is mounted on a mechanical manipulator so that the wire can be dipped into the solution to a desirable depth, and can also be lifted out of the solution. Usually a section of about 5 to 8 mm should be immersed in the solution. A counter-electrode, either a piece of Pt foil or simply a piece of tungsten wire, can be a loop or simply a straight piece of foil or wire. It is essential that the tip specimen wire is held in the vertical position so that the convection of the solution during the polishing can be... 

Pour 50 ml of a 0.1 aqueous or ethanol solution of potassium hydroxide or potassium nitrate into four 100-ml heakers (use two of them for each solvent). Using a stationary setnp for determining the electrical conductance (Fig. 50), check whether these solutions conduct an electric current. For this purpose, immerse the carhon electrodes into a heaker with the relevant solution and observe the reading of the ammeter. See that the electrodes are always immersed to the same depth. When transferring the electrodes from one solution into another one, wash them with distilled water. 

In an isolated electrode, the VB, the GB and the Fermi level all have constant values throughout the depth of the electrode. If it is immersed in an electrolyte there will be a movement of charge at the interface so that the Fermi level coincides with the redox level of the species contained in the electrolyte. This is somewhat similar to the equalization of the levels of two liquids in contact, the equilibrium condition being that the pressures should be equal at the point of contact. In an energy diagram this is shown as a... 

Griscom battery — This was a chromic acid (carbon electrode) - zinc - battery with a mechanism to control the depth of immersion of the electrodes in the electrolyte. The latter was attempted to regulate the current for sewing machines. 

Dependence of nmlx /nmi and nm lng ratios on the angular velocity of centrifugation GJ and on the depth of immersion of electrodes in the foam Al... 

In a vessel for electrolysis three parallel nickel plates were installed. The inner nickel plate was the working electrode (anode), and the two outer nickel plates were counter electrodes (cathode). A 1.2 liter mixture consisting of fluorene (0.01 mol) and LiPFs (0.1 mol) dissolved in propylene carbonate were then added to the vessel. The three nickel plates were immersed in the mixture to a depth of 90 mm. Two lithium metal sheets were used as reference electrodes, with each sheet placed between the anode and the cathode. The electrolysis was carried out by a potential-sweep method for 4 hours under a potential width of 4.5 to 6.7 V with a sweep time of 50 mV/s. The inner... 

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