Operating regime plot

An operating regime plot can then be employed to provide further insight into the choice of operating conditions for a displacement process. Use of this plot is particularly important for a selective displacement process which typically has narrower operating regimes for successful operation. 

For the operating regime plot the elution line and the displacement line have to be calculated for each substance. The elution line is calculated by an itinerate approach. In the following equation the values for qj on both sides are changed in such a matter that they become nearly equal. 

The answer is found by spotting the operating point on the map of fluidization regimes plotted in Fig. 1. Calculating the necessary parameters, we find the Archimedes number from Eq. (3) ... 

This number group may be used to determine in which regime a centrifugal atomization takes place for given operation conditions and material properties. Since the group is not dimensionless and the plot was made using SI units, it should be used with caution. From Fig. 4.3, 132°1 it can be seen that for a given liquid metal/alloy at a... 

Bias-dependent measurements were performed in order to check to what extent the mechanism depends on the electrical operation conditions. Fig. 43 shows double-logarithmic plots of the electrode polarization resistance (determined from the arc in the impedance spectrum) versus the microelectrode diameter observed at a cathodic bias of —300 mV and at an anodic bias of +300 mV respectively. In the cathodic case the electrode polarization resistance again scales with the inverse of the electrode area, whereas in the anodic case it scales with the inverse of the microelectrode diameter. These findings are supported by I-V measurements on LSM microelectrodes with diameters ranging from 30-80 pm the differential resistance is proportional to the inverse microelectrode area in the cathodic regime and comes close to an inverse linear relationship with the three-phase boundary (3PB) length in the anodic regime [161]. 

These examples are based on both electrodes operating in the activation polarization regime, in which the logarithm of the current is proportional to the overpotential. However, there are situations - particularly at low concentrations - in which the electrochemical reaction is limited by mass transport to the electrode surface. This is referred to as concentration polarization, and is illustrated in Figure 13.2d. In this case, above a critical overpotential the current becomes constant, which appears as a vertical line in the plot. A new mixed potential is established at the intersection of this vertical line and the cathode polarization for the oxygen reduction. This potential depends on the gas concentration, and thus can be used for the chemical sensor signal. 

Plots of substrate bulk concentration vs the dimensionless reactor length47 show how steep the descent of profiles can be when large Thiele moduli are approached. Substrate conversion is therefore more rapid in the diffusion controlled regime, and reactors are better operated in this regime. 

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