Protective Measures with Silicones

As an example, a tank farm that is to be cathodically protected by this method is shown schematically in Fig. 11-4. As can be seen in the figure, injection of the protection current occurs with two current circuits of a total of about 9 A, via 16 vertically installed high-silicon iron anodes embedded in coke. These are distributed over several locations in the tank farm to achieve an approximately uniform potential drop. The details of the transformer-rectifier as well as the individual anode currents are included in Fig. 11-4. Anodes 4, 5 and 6 have been placed at areas where corrosion damage previously occurred. Since off potentials for 7/ -free potential measurements cannot be used, external measuring probes should be installed for accurate assessment (see Section 3.3.3.2 and Chapter 12). 

Fig. 4.15 (a) Silicon carbide varistors, and (b) zinc oxide varistors. (Courtesy of P.D. Devices Ltd. UK.) (c) PTC thermistors for motor protection and (d) NTC thermistors inset, catheter fitted with biomedical NTC thermistor for measuring blood temperature. (Courtesy of Thermometries.)... 

Aluminium has a close chemical affinity with silicon, which may have a role in protecting against aluminium toxicity (94). Serum aluminium and silicon concentrations were measured in hemodialysis patients from four different centers. Although there was no relation across all centers combined, in one center there was a reciprocal relation in patients on home hemodialysis (who did not require reverse osmosis). Median (range) aluminium concentrations were higher, 2.2 (0.4-9.6) pmol/l when serum silicon was less than 150 pmol/l, and lower, 1.1 (0.2-2.8) pmol/l when serum silicon was greater than 150 pmol/l. In patients treated by hemodialysis without reverse osmosis, high serum silicon concentrations were associated with lower serum aluminium concentrations. Further work is needed to confirm a preventive role for silicon in the accumulation and subsequent toxicity of aluminium in dialysis patients. 

The sensor chip was bonded to a socket with inlet and outlet flow channels. The aqueous solution to be measured was pumped through the inlet tubes into the silicon chip cavity coated with a 220 nm thick PECVD silicon nitride film to provide chemical protection. In the present work, three sensor designs have been used ... 

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