The sludge oils were produced necessarily in the ships operation, so that it will be the best way to manage the sludge oils inside ship itself from a viewpoint of the prevention of marine oil pollution from ship. The present study deal with the ultrasonic breaking systems which recycle the sludge oil from ships into usable oil to be burnt. The first place, experimental studies were carried out to investigate the homogenizing effect of the marine oils by repeated vibration of ultrasonic transducer. Variation of the properties(viscosity, specific gravity and pH) and the matrix structures for the environment of various marine oils were interpreted to analyze the breaking, dispersion effects by cavity. The experimental results can be useful to the development of sludge oil disposing systems.

Quality costs seem to be one of the effective tools to assess quality management activities, but shipping industries have not controlled quality costs because of difficulty in cost itemization and cost data collection. This study has attempted to itemize shipping quality costs in detail and researches the composition of actual quality costs of sampled shipping companies in Korea. Result of research shows that stopping quality costs were composited by 24.3%, 3.8% and 71.8% of prevention costs, appraisal costs and failure costs, respectively and very high relationship between total qualify cost and other quality costs. This research also recommended practical methods for quality management by using indexes of quality costs.

A Plankton ecosystem model was developed to investigate effects of hydrodynamic processes including advection and diffusion on size-structured phytoplankton dynamics in the mesohaline zone of the York River estuarine system, Virginia, USA. The model included 12 state variables representing the distribution of carbon and nutrients in the surface mixed layer. Groupings of autotrophs and heterotrophs were based on cell site and ecological hierarchy Forcing functions included incident radiation, temperature, wind stress, mean How and tide which includes advective transport and turbulent mixing. The ecosystem model was developed in FORTRAN using differential equations that were solved using the 4th order Runge-Kutta technique. The model showed that microphytoplankton blooms during winter-spring resulted from a combination of vertical advection and diffusion of phytoplankton cells rather than in-situ production in the lower York River estuary.