Computer plot attack

Figure 3. Computer plot obtained by isochronous interpolation of the experimental light-scattering data (O) of HEC during endocellulase attack. The Langrangian interpolation functions are given by the horizontal curves ana the isochronous interpolated Kc/Re values by A. The quadratic least squares extrapolations to zero angle ( ) are given by the...

The most traditional way to analyze electrochemical noise data has been to transform time records in the frequency domain in order to obtain power spectra. Spectral or power density plots would thus be computed, utilizing fast Fourier transforms (FFT) or other algorithms such as the maximum entropy method (MEM). Some studies have indicated that the roll-off of the voltage noise amplitude from corroding electrodes could be a useful characteristic of corrosion processes. In these studies, a roll-off of 20 dB/decade was associated with pitting attack, whereas one of 40 dB/decade was found to be characteristic of general corrosion processes. When converted into a spectral density plot, a roll-off of 20 dB/decade would correspond to a spectral exponent of 1, and a roll-off of -40 dB/decade, to an exponent of 2. 

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