A titanium nitride (TiN) electrode with very low resistance and good electrochemical stability was constructed and used for electrochemical inactivation of the marine Gram-negative bacterium Vibrio alginolyticus. Specific resistance of the TiN electrode, which was formed by reactive sput tering, was 1.1 × 10-4 Ω·cm. When cyclic voltammetry of the TiN electrode-attached V. alginolyticus cells of 4.2 × 105 cells/cm2 was carried out at a scan rate of 20 mV/s in seawater, an anodic peak current appeared around 0.68 V vs Ag/AgCl. In all, 98.7% of V. alginolyticus cells attached onto the electrode were inactivated by applying a potential of 0.8 V vs Ag/AgCl in seawater for 30 min. Changes in pH and chlorine concentration were not observed at 0.8 V vs Ag/AgCl. The TiN electrode was oxidized by applying potential of a 0.8 V vs Ag/AgCl and passivated by formation of TiO2 onto the electrode surface. The TiO2 thin layer formed on the TiN electrode surface did not impede electrochemical inactivation of marine bacteria. These results show that the TiN electrode can be used as an electrode for electrochemical inactivation of marine bacteria.

Biofouling is the undesirable adhesion and development of microorganisms and macroorganisms in a water environment. An electrochemical antifouling system based on management of primary adhesion of microorganisms was developed employing titanium electrode for antifouling of seawater cooling pipes and marine infrastructures. The system consists of an electrochemical reaction-monitoring unit, a power control unit, and a potential/current remote monitoring and a control unit. Titanium plates and iron plates were used as the working and counter electrode, respectively. Field experiment was conducted in the seawater cooling pipeline system of a thermal power station. Four titanium electrodes with 1.0 m length and 3.0 m width were set in the seawater intake pit and current density was controlled at 50-100 mA/m(2). The electrode surface maintained clean conditions for 2 years. The average wet weight of fouling organisms on the titanium electrode surface was below 100 g/m(2) whereas the corresponding wet weight was above 10 kg/m(2) on the control surface. Using titanium as the electrode material, chlorine and hypochlorite are not generated. The developed electrochemical antifouling system provided an effective, environmentally friendly, and feasible techniques for remote operations.

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The capsule endoscope authorized in some countries in late years has the advantage of preparing the observation in difficult small intestines in a past endoscope. However, because the promotion mechanism of a capsule endoscope depends only on the peristaltic motion of a digestive organ, the oversight of change to a morbid state is feared. Authors aim at the achievement of a free movement and remote diagnoses in small intestines, and are developing a locomotive system for capsule endoscopes. This paper describes the proposal of the locomotive system with an electromagnetic actuator, and examination of a simulation model for this locomotive system.