Resistance monitoring methods

The electrical resistance (ER) method to monitor physical changes in an electrically conducting material is well known(6). 10 cm x 2.5 cm coated iron foils of 10 micron thickness were electrically resistance monitored during exposure to various corrosive environments to follow metal thickness loss at the paint/metal interface. The circuit shown in Figure 1 allowed foil resistance increase AR, which is directly related to metal thickness loss Ad according to Equation (1), to be determined within 0.003 microns. 

There are only a few measurements that have shown a 10"14 Ohm-cm resistivity one method is by establishing a current flow in a ring of superconductor and monitoring the decay. 

Miyata, T., Detection and monitoring methods for resistance in arthropods based on biochemical characteristics, in Pest resistance to pesticides, Georghiou, G.P. and Saito, T., Eds., New York Plenum Press, 1983, p. 99. 

We developed the numerical analysis assisted monitoring method for the coating condition on a ballast tank wall. We proposed that the coating condition is evaluated with the surface resistance. We developed the identification method to obtain the whole surface resistance from the differential potential induced by the impressed current from an optional anode inside a tank. We introduced differential potential measurement and inverse analysis to obtain the surface resistance representing the coating condition. The potential measurement and quantitative evaluation were conducted in the actual ship. The verification was performed and there was the good agreement between the proposed method and the preliminary visual inspection. 

Pest/Natural Enemy Complex/ apple USA Monitoring, Lack of Croft 1982, Resistance in Key Pests, Croft et al. 1984, Resistant N.E., Selective Croft et al. 1987 Pesticides, Biological Control/Grower Compliance, Improved Monitoring Methods ... 

Biological indicators (i.e. preparations of bacteria cultures, usually spore of selected resistant strains) are must less reliable than physical monitoring methods, except in Ethylene Oxide Sterilization. 

Iwasaki A, Todoroki A. Statistical evaluation of modified electrical resistance change method for delamination monitoring of CFRP plate. Struct Health Monit Int J 2005 4(2) 119-36. http //dx.doi.org/10.1177/1475921705049757. 

Electrochemical monitoring methods have also been developed for application on steel reinforcement in concrete. These methods include potential measurement on the concrete surface, linear polarization (LPR) and determination of polarization curves [9.17]. Electrical resistance probes (ER) and probes embedded in the concrete for measuring galvanic current have also been used. 

Kihira et al. [118] applied EIS to investigate the condition of the rust film formed on the weathering steel, and proposed new corrosion monitoring method based on rust film resistance. Nishimura et al. [119] measured the electrochemical impedance of a carbon steel covered with rust film formed in a wet/dry environment containing chloride ions. They reported that the charge transfer resistance (/ p) increased with the wet-dry cycles of exposure. 

Todoroki A, Tanaka M, Shimamura Y. Electrical resistance change method for monitoring delaminations of CFRP laminates effect of spacing between electrodes. Compos Sci Technol 2005 65(l) 37-46. 

The linear polarization-resistance (LPR) technique is the only corrosion monitoring method that allows corrosion rates to be measured in real time. Although limited to elec-trol3rtically conducting liquids, the response time and data quality of this technique make it superior, where applicable, to all other forms of corrosion monitoring. 

---