본 연구는 가스추진 174K급 LNG 운반선의 가스 압축기실에서 발생하는 가스누출 모사를 통해 가스탐지기의 최적 위치를 분석 하였으며, 새로 개정된 IGC 코드에 명시된 안전규정을 만족하는 합리적인 방법도 함께 제안하였다. 가스압축기실에서의 LNG 가스누출 수치해석을 위해, 실제 ME-GI 엔진이 장착된 174K급 LNG 운반선의 압축기실 형상과 장비, 배관의 배치와 같은 치수로 3D 설계되었다. 가 스누설에 대한 시나리오는 305 bar의 높은 압력과 1 bar의 낮은 압력을 적용하여 진행하였다. 고압용 핀홀의 크기는 4.5, 5.0, 5.6 mm이고 저압용은 100, 140 mm이다. 해석 결과, 5.6 mm 핀홀(고압)과 100, 140 mm 핀홀(저압) 상태의 누출에 대한 환기평가에서 가연성 가스농도는 심 각한 위험이 없음을 확인하였다. 그러나 개정된 IGC 코드에 따라 설치된 압축기실의 가스 감지 센서의 실제 위치는 다른 지점으로 이동 해야 하고, 측정 지점이 현 규정에서 요구하는 것보다 더 추가되어야 함을 확인하였다.

The recent increase in crude oil trading has led to an increase in the workings of SPM for crude oil carriers. VLCCs generally encounter difficulty entering port due to limitations in terms of sea depth and maneuverability. The SPM is a system that allows mooring to the buoy located in the outer sea for such vessels. However, the buoy is more affected by relatively external forces because of their offshore location. Therefore, the safety assessment of SPM is particularly important as it can lead to large oil pollution disasters in the event of SPM accidents. Despite this, in the implementation of the Marine Traffic Safety Audit Scheme in Korea, there exists no guidance for SPM. In this study, a SPM mooring safety assessment is performed using OPTIMOOR, a numerical analysis program, so as to understand the mooring characteristics of SPM. As a result, it is confirmed that the tension of mooring lines and hull movement in the SPM are greatly affected by the encounter angles with external forces. In addition, it is found that the maximum tension of the mooring line is elevated as the water depth becomes shallower through sensitivity analysis. According to SPM characteristics, which has a large influence on the encounter angle, this study has proposed an amendment to setting criteria in the implementation of the Maritime Traffic Safety Audit Scheme which could improve the reliability and accuracy of mooring safety assessments.

In this research, we have calculated characteristics of wave-piercing high-speed planing hull, by using a RANS solver and overset grid method, for comparing with experimental measurements of that and simulating with several appendages, since the computed results of commercial CFD code look reasonable for the prediction of the performances of planing hulls on calm water in planing conditions. As a result, it is confirmed that the dynamic instability phenomena in pitch and heave motions (porpoising) occurred after a certain FnV, and effectively suppressed using some of appendages, especially the 0.5L spray rail is suppressed to 24-55 % in the pitch motion and 33-55 % in the heave motion. In spray phenomenon, 1L hard chine suppress spray effectively and it is effective to set the angle of appendages to be less than 0° in order to suppress wave.

Control allocation is an important part of a system. It implements the function that map the desired command forces from the controller into the commands of the different actuators. In this paper, the authors present an approach for solving constrained control allocation problem in vessel system by using multi-parametric quadratic programming (mp-QP) algorithm. The goal of mp-QP algorithm applied in this study is to compute a solution to minimize a quadratic performance index subject to linear equality and inequality constraints. The solution can be pre-computed off-line in the explicit form of a piecewise linear (PWL) function of the generalized forces and constrains. The efficiency of mp-QP approach is evaluated through a dynamic positioning simulation for a vessel by using four tugboats with constraints about limited pushing forces and found to work well.

The p-dioxanone can be used to make a variety of commercially useful products particularly where biodegradability is desired, such as fibers, sutures, molded articles, containers, medical devices and surgical clips, film and compostable trash bags. The mole fraction solubility of p-dioxanone in various solvents such as acetone, ethylacetate, tetrahydrofuran, methanol, ethanol, 1-propanol, 1-butanol and 1-pentanol were measured over the temperature range from 263.05 K to 288.45 K. The solubility of p-dioxanone increases with increasing polarity of the solvents.

We investigated on the additive effect of carbon nanotube in the sulfur electrode on the first discharge curve and cycling property of lithium/sulfur cell. The sulfur electrode with carbon nanotube had two discharge plateau potentials and the first discharge capacity about 1200 mAh/g sulfur. The addition carbon nanotube into the sulfur electrode did not affect the first discharge behavior, but improved the cycling property of lithium/sulfur cell. The optimum content of carbon nanotube was 6 wt% of sulfur electrode

With the recent increase in the volume of liquid cargo transportation, there is a need for STS( Ship To Ship) globally. In the case of the STS mooring, the safety assessment should be conducted according to other criteria because mooring is different from the general mooring at the quay, but there is no separate standard in Korea. Thus in this study, STS mooring simulation and sensitivity analysis using OPTIMOOR program, the numerical analysis program, was conducted to identify the characteristics of the STS mooring. The target sea modeled the Yeosu port anchorage in Korea and the target ship was selected as the case of VLCC (Very Large Crude Oil Carrier)-VLCC. Through the numerical simulation and sensitivity analysis, the characteristics of STS mooring were identified. Also based on these results, we focused on establishing the standard for STS mooring safety assessment. Numerical simulation results show that the STS mooring safety can be changed according to a ship's cargo loading condition, pre-tension of mooring line, sea depth, encounter angle with the weather, and the weather condition. Additionally, the risk matrix is prepared to establish the safe external force range in the corresponding sea area. This result can be used to understand the mooring characteristics of STS and contribute to the revision of mooring safety assessment criteria.

식물추출물로부터 보다 안전하고 효과있는 새로운 tyrosinase 저해제를 개발하기 위한 연구의 일환으로 먼저 기존의 spectrophotometric assay를 개선한 새로운 TLC 검색방법을 사용하여 여러 식물추출물을 검색한 결과 백자인의 메탄올추출물이 강한 tyrosinase 저해활성을 갖고 있음을 알 수 있었다. 따라서 백자인의 메탄올추출물로부터 tyrosinase 저해제를 분리하기 위하여 먼저 탈지 메탄올추출물을 에테르, 에틸아세테이트