AA-size Nickel-Metal Hydride (Ni-MH) secondary (rechargeable) batteries can be used to replace primary (disposable) batteries on portable electric devices for marine use such as wireless LAN voice call apparatus. This study investigates the extent to which AC impedance response analysis can verify battery deterioration during its life cycle. Verification of battery deterioration levels using this analysis has been confirmed under small scale conditions with AB5 alloy structure type Ni-MH batteries but not with super lattice alloy structure type Ni-MH batteries. Using the terminal voltage during cycle mode experiments and the statistical analysis of Mahalanobis distance, evaluation of battery deterioration levels of super lattice alloy type batteries was conducted. This study's goal is to verify whether the AC impedance method can be applied to check the state of health (SOH) of on-board batteries under operating conditions.

The effect of two-room type electrolysis on the alkalization of seawater was investigated in order to improve the performance of SOx scrubbers for ship exhaust. The simulated seawater was electrolyzed using carbon electrode, and the pH, voltage, current, input power and alkalinity values were measured. The energy efficiency in the two-room type electrolysis was evaluated in comparison with a one-room type and a magnesium electrode type. Under equivalent electrolytic conditions, the two-room type exhibited an energy efficiency 2.3 times higher than that of the one-room type, although its efficiency was only one seventh of that of the self-sacrificial magnesium electrode type.

Bolts and nuts are the most commonly used machine elements to clamp multiple parts and structural members. When a bolted joint is subjected to thermal load, the bolt preload varies greatly or to some extent and the bending moment may be generated in the bolt body, due to differential thermal expansions among clamped parts. The variations of bolt preload and bending moment sometimes cause failure or fracture of the bolted joint, and it may lead to fatal accidents of machines and structures. In this paper, a simplified method for estimating the variations of bolt preload and bending moment with time is proposed using elementary theory of solid mechanics. The required input data are the surface temperatures around the bolted joint, which can be measured by thermography without touching the target structure. The effectiveness of the proposed method is demonstrated by comparing the estimated values with those obtained by three-dimensional Finite Element Analysis.