Fouling layer measurement

Measuring Fouling Layer Morphology and Cell Adhesion Kinetics.331... 

In an attempt to directly measure the amount of material in the fouling layer, Dejmek et al. (15) studied the ultrafiltration of 131 l-labelled casein. A very slow accumulation at the membrane surface was observed, superimposed on the expected changes due to feed flow rate, applied pressure, etc. 

Contact angle measurements showed that it depends on the membrane material if the fouling layer makes the membranes more hydrophilic or hydrophobic. 

Riedl et al. [58] employed an atomic force microscopy (AFM) technique to measure membrane surface roughness and scanning electron microscopy (SEM) to assess the fouling layer. The smoothness of the membrane surface can influence the morphology of the fouling layer. It was shown that smooth membranes produced a dense surface fouling layer. 

Electrochemical shear probe Measurements membrane surface shear rate in the presence of air sparging. Online measurement with high speed camera allows the observation of bubble shapes No visualization of fouling layer [77]... 

Thus, at each time increment, the newly formed surface layer has not been compressed and the mass in the surface layer is estimated by the measured increase in fouling layer thickness due to cake growth and the surface porosity of a... 

Figure 15.7 A time course of fouling layer thickness measured under AP = 61 kPa for 0.5% cross-linked S. cerevisiae suspension.

Another area where probes can be used effectively is in monitoring of deposits such as scale. One method of measurement is detecting specific ions that contribute to scale buildup or fouling another is measuring the ac tual layers. Scale and fouling often devastate the corrosion resistance of a system, leading to a costly corrosion-related plant shutdown. 

The fouling of the probe when inserted into a duct or pipe acts as an isolating layer and increases the measurement error. To avoid this conduction error, the probe should be a poor heat conductor. In measuring surface temperatures, the probe should not have an insulating effect, as this will change the temperature in the measuring point. 

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