A Study on Prismatic Pressure Vessel Type of LNG Fuel Tank for LNG Fuelled Ship

This study focuses on the necessity and the feasibility of LNG fuelled ships by analyzing industrial trends driven by environmental regulations on air-polluting exhausts from marine engines. Design and arrangement of an LNG fuel tank is critical to build LNG fuelled ships since an LNG fuel tank is more voluminous and costly than the case of the corresponding HFO tank. Furthermore, designing the tank to meet safety regulations required by IGF Code is difficult and sometimes requires development of new shape of a ship, resulting in a negative impact on cargo spaces. Recently, about 85 ships are using LNG as fuel, and most of them have adopted “Type C Independent Tank – Cylindrical Type”. It is difficult to make a proper arrangement in installing this type of tank. Hence, it might be a major challenge when the size of the tank should be increased significantly for long distance voyage. Compared with other ships, tankers have enough deck space to arrange an LNG fuel tank on. For container ships, however, position of the tank highly affects cargo capacity as cargoes are stored on deck and inside hull. Bulk carriers are faced with the same problem as container ships are due to their hatch covers and deck facilities. Bulk carriers account for the largest share of total ships in number. It is estimated that 20~30% of small and mid-scale bulk carriers will use LNG as fuel. Until now, no bulk carriers have adopted LNG as fuel. Only two cement carriers are sailing on LNG though these are special purpose vessels with special ship shape. Therefore, on the premise that cargo loss caused by the LNG fuel tank should be minimized, this thesis studies the stability and optimal arrangement of LNG fuel tank by comparing and analyzing between a cylindrical pressure tank and a prismatic pressure tank (called the “Lattice Pressure Vessel”) on the basis of standard design of a 50k bulk carrier.Contents List of Figures iii List of Tables v Abstract vi Nomenclature viii 제 1 장 서 론 1 1.1 연구 배경 1 1.2 연구 목적 2 1.3 문헌 조사 3 제 2 장 환경법 규제 트렌드 및 관련 기술 분석 9 2.1 선박 배기 오염물질 9 2.2 환경법 규제 트렌드 분석 10 2.3 환경법 규제 대응 기술 14 2.4 LNG연료 추진선 산업 동향 및 전망 15 2.5 선종별 LNG 연료추진선 탱크 배치 분석 17 2.6 LNG 연료저장탱크에 대한 기술 22 제 3 장 LNG 연료추진 50K 벌크선의 격자형 압력탱크(LPV) 설계 30 3.1 연구 목적 선박의 기본 제원 30 3.1.1 선종 및 항로 선정 배경 30 3.1.2 메인 엔진 선정 32 3.1.3 연료탱크 타입 및 용적(Volume) 34 3.2 격자형 압력 용기 설계 35 3.2.1 기술적 특성 35 3.2.2 격자형 압력 용기 설계 규정 36 3.2.3 기본 공식 38 3.2.4 탱크 설계 40 3.2.5 탱크 설계 도면 43 제 4 장 결과 및 고찰 45 4.1 실린더형 탱크와 격자형 탱크의 기술비교 45 4.1.1 부피 효율 및 무게중심 고찰 45 4.1.2 설계 하중(Design load) 48 4.1.3 BOG와 롤 오버(Roll over) 49 4.2 LNG연료추진선의 탱크 최적배치 시 고려사항 53 4.3 50k LNG 연료추진 벌크선의 탱크 최적 배치 61 4.3.1 LNG 탱크 배치 61 4.3.2 부피 효율성과 설치 공간 64 제 5 장 결 론 68 제 6 장 참고 문헌 69Maste

2021~2030년 초고성능컴퓨팅 육성을 위한 국가초고성능컴퓨팅 혁신전략

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Composite Measures of Supercomputer Technology

We have developed composite measures of supercomputer technology, reflecting various factors of supercomputers using Martino's scoring model. CPUs, accelerators, memory, interconnection networks, and power consumption are chosen as factors of the model. The weight values of the factors are derived based on a survey of 129 domestic and international experts. The measured values are then standardized to integrate measurement units of the factors in the model. This model has been applied to 50 supercomputers, and rank correlation analysis was performed using representative measures. As a consequence, the ranking drastically changes except for the 1st and 2nd supercomputers on the TOP500. In addition, the characteristics of memory and interconnection networks influence the ranking, and the results demonstrate that the proposed model has low correlations with HPL and HPCG but a high correlation with Green500. This indicates that power consumption is an important factor that has a significant effect on the measures of supercomputer technology. In addition, it is determined that the differences between the HPL ranking and the proposed model ranking are influenced by power consumption, CPU theoretical peak performance, and main memory bandwidth in order of significance. In conclusion, the composite measures proposed in this study are more suitable for comprehensively describing supercomputer technology than existing performance measures. The findings of this study are expected to support decision making related to management and policy in the procurement and operation of supercomputers