Zero-Driving Force Method

A related method to separate electronic and ionic conductivities has been extensively discussed by Riess.253 As in the previous 

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Short-circuit method ( zero driving force method)... 

The partial ionic or electronic currents and conductivities can also be measured by setting the driving force for the other partial current to zero. If one examines the Hebb-Wagner method, it becomes apparent that this nullification also occurs there. Because of the extreme resistance of the ion-blocking electrode to ionic current, the driving force for ionic motion in the MI EC vanishes (V/iion = 0). 

The second question to be addressed is tiiat of solvenf flow rate, minimum and actual. The conventional method of establishing conditions for a "pinch" (i.e., a vanishing driving force Y - Y = 0) no longer applies since Y was declared to be zero. In fact, the entire conventional use of the operating diagram becomes invalid, a feature further explored in Practice Problem 8.4. The minimum here is dictated not by a phase equilibrium but rather by tiie stoichiometry of the reaction. Thus, if 1 mol/s of HjS needs to be absorbed and neutralized, a minimum of 2 mol/s of NaOH has to be made available. 

In this case the forcing is absent from (53) and the initial conditions drive the instability. We will proceed using transform methods rather than the standard normal mode analysis. It is useful to analyze the stability in a frame which moves with the jet velocity F, thus making the base flow zero. The initial conditions for equations (53), (54) are taken to be of the form... 

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