The loudspeaker is the directly radiated speaker which generates the sound by the vibration of cone paper. Therefore the shape and the vibration characteristics of th cone paper is important factors affecting the performance of speaker. The vibration mode of cone paper is piston mode that vibrates to the up-down direction, and we can see the divided vibration in the higher mode. Because the loudspeaker has a damper, the vibration mode is different to the mode of the only cone paper. In this study, the vibration mode of cone paper which considering the damper and the effects of the damper diameter were investigated by finite element method

In the world economy and the shipping industry, container, bulk carriers and oil tanker vessels are undergoing a bigger difficulty because of the imbalance on supply and demand with the view that ship's loading capacity is exceeded. For this reason, shipping companies are trying to reduce the operating cost through slow steaming. Thus, under this condition of continuous recession in shipping industry, saving on fuel consumption is the main issue. In this study, tests were conducted to find out the method of reducing fuel oil consumption by economically operating the ships, taking into account the main engine power and speed. The subject vessel's fuel consumption compared to the output is lower near the range of 138~157RPM. The engine speed showed significant increment to 144RPM and fuel consumption increased rapidly compared to the engine speed at 15knots and above. During sea trial test, the subject vessel's specific fuel rate(SFR) was 134.25[g/BHPh] while the calculated value after 10 years of operation is 137.1[g/BHPh] at speed range of 148~150RPM which is 70% of the load and this indicates an increase of approximately 2.1%.

Fuel pump of a vehicle is a device to supply the fuel from fuel tank to engine. This study analyzed the pulsatility on the shape of fuel supply pipe using a CFD(Computational Fluid Dynamics). Numerical analysis was performed to use 3-dimensional incompressible k-ε turbulent model with measured pressure values at an exit by an experiment. Simulation models used commercial and improved model. In this study, the characteristics of the pulsatility reduced in improved model compared to those in commercial model. The pressure loss, which occurs at the flexure, was effective to pulsatile reduction. Commercial and improved model differed by numbers of flexure. The number of flexure between inlet and outlet decreased the difference of velocity and pressure. Therefore, the design of fuel supply pipe should be considered numbers and shape of flexure.