Redox depletion

F7. Depleted Dark Surface. For nse in all LRRs except W, X, and Y for testing in LRRs W, X, and Y. Redox depletions, with valne 5 or more and chroma 2 or less, in a layer at least 10 cm (4 in.) thick entirely within the npper 30 cm (12 in.) of the mineral soil that has either of the following ... 

Unique characteristics of ferromanganese nodules and associated oxidation-reduction reactions have been used by soil scientists as morphological indicators to help identify hydric soils (see Chapter 3). These characteristics are termed by soil scientists as redoximorphic features however, various terms such as redox concentrations, redox depletions, and reduced matrix are synonymously used for the oxidation-reduction of iron and manganese and their respective concentrations. We prefer not to define these characteristics as redoximorphic features because oxidation-reduction reactions not only involve iron and manganese but also a range of elements that support biotic communities in the biosphere. 

Hydrochloric acid test 1 10% HCl 24 h in boiling solution 1. Appearance of sample after bending around mandril 2. Mass loss per unit area (a) Redox pxjtential = -I-0-32 (b) Corrosion potential = -0-2 0-1 1. Alloy-depleted area 2. Not for 0-phase... 

The equilibration proceeds by electron transfer between the semiconductor and the electrolyte. The solution levels are almost intact ( REdox — redox)> since the number of transferred electrons is negligible relative to the number of the redox system molecules (cox and cred). On the other hand, the energy levels of the semiconductor phase may shift considerably. The region close to the interface is depleted of majority charge carriers and the energy bands are bent upwards or downwards as depicted in Fig. 5.60b. 

Starting at Fr, as soon as a current / is imposed, the equivalent flux of redox-active substrate A to the electrode is established. Since i is constant, the slope of the concentration profile must also be constant. Thus, depletion of the substrate causes an increase in the diffusion layer thickness, while the steepness of the profile does not change. The concentration of A at X = 0 necessarily decreases. Simultaneously, cr (x = 0) increases. As a consequence, F adjusts according to equation (1). 

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