Passive interception

The term passive interception is used to describe recovery systems that rely upon natural groundwater flow to deliver free-phase NAPLs to the collection facility without the addition of external energy (such as pumping). These systems often include linear interception-type systems such as trenches (or French drains), subsurface dams ( funnel-and-gate structures), combined hydraulic underflow with skimming, and density skimming units. 

Linear interception Passive Low to high 0-10 Yes No Loosely consolidated formations ... 

Finally, all reactions may occur, and no simplification of Eq. (7.114) is possible. Both the slope of the plot and the intercept will be potential dependent and the latter will be greater than 1/A. These possibilities are all portrayed in Fig. 7.53. From such results the conclusions drawn for oxygen reduction on a pure Fe surface were that on the bare iron, the rate-determining step involves the formation of Oj, while on the passive layer it is oxygen chemisorption under Temkin conditions. 

Figure 7.104 shows the plot of the value of J vs. S obtained for different potentials on the bare iron region from the data plotted in Fig. 7.103. A straight line obtained with an intercept much greater than 1 indicates that Oz reduction on reduced iron proceeds by the direct four-electron reaction pathway. Formation of HjOj as an intermediate in the consecutive reaction pathway is less than 1 % of the total reduction current Conversely, in the potential region corresponding to passive iron, the slope, S, of the /disk//ring plot is zero, and the intercept J = (l/N) indicates that 02 reduction on passive Fe is a two-electron process in which is the product, and not an intermediate, of the reaction.

N(e) is the number of transverse cracks which intercept the length X(e). The error introduced when counting the number of cracks is 2 cracks per millimeter. In order to describe the cracking response of our passivation films, the experimental values of the crack density as a... 

The sees includes two trains each train may remove 100% of the core decay power. In an accident causing the reduction of the core coolant flow (such as station black-out or primary pump trip), activation is automatic (without intervention either by the operator or by the control and supervision system, because the PSC interception valves are kept in a closed position by forces from the primary coolant flow and start opening when this flow decreases below a set-point value) the operation of the system is completely passive. 

The potential modulation reflectance is thought to be followed by the Mott-Schttoky type plot as well as the capacitance. Such type of the plot is shown in Fig. 32 with the original plot for the capacitance for the passive oxide formed at 1.55 V vs. RHE in pH 9.6 borate solution. The intercepts on the abscissa, which is corresponding to ( f - RT/F), are in coincident with each other. From the intercept the flat band potential can be estimated to be f = 0.35 V vs. RHE. 

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