• 대한조선학회논문집
• /
• 제53권3호
• /
• pp.228-236
• /
• 2016

Extraordinarily the establishment of towing tank has been initiated after the allocation of space at the basement floor of existing building through remodeling procedure. Therefore the asymmetric tank should be unavoidably determined by compromising with the allowable space and existing building structure. Consequently the shape of towing carriage ought to be selected as a cantilever type to match with the given environmental conditions. Finally the major role of the towing tank has been configured on the fundamental research work for the high speed marine vehicles. Due to the limited length of towing tank, it is appeared that the carriage should accelerated with 1.2m/sec² which is equivalent to twice of the maximum acceleration in ordinary practices on design application of carriage. In such a condition the exerted total power of motor could not be converted to traction force of the carriage without slip for the acceleration. To overcome these difficulties the contact pressure of a horizontal traction wheel to rail has been reinforced by the elastic recovery force of springs on supporting rollers. It is believed that the design experience of the high speed towing carriage under unusual circumferential condition and acceleration barrier could be utilized not only on the design of high speed towing carriage but also on the improvement of existing facilities.

• Asian review of World Histories
• /
• 제3권2호
• /
• pp.201-218
• /
• 2015

World history today has been greatly influenced by the fact that it was the revolution in naval power during the past two centuries that made the world truly global. This has led to a new master narrative that re-framed five millennia of recorded history in order to explain the ultimate triumph of the maritime economies. The result of such revision is to underestimate and distort the role of continental Eurasia in the shaping of the three key civilizations that developed independently and remain distinct: the Mediterranean, the Indic and the Sinic. Only by a fuller reappraisal of the linkages of trade and war dominated by the Eurasian central forces for most of history can we understand the global pressures perennially at work. By setting the continental and the maritime in their total historical context and recognizing their importance today, we can better explain what is happening and what is likely to continue to influence the course of world history.

• 대한조선학회논문집
• /
• 제59권3호
• /
• pp.183-191
• /
• 2022

A design method for a propeller type rim-driven axial-flow turbine for a micro-hydropower system is presented. The turbine consists of pre-stator, impeller and post-stator, where the pre-stator plays a role as a guide vane to provide circumferential velocity to the on-coming flow, and the impeller as a rotational power generator by absorbing angular momentum of the flow. BEM(Blade Element Method), which is based on the turbine Euler equation, is employed to design the pre-stator and impeller blades. NACA 66 thickness form and a=0.8 mean camber line, which is widely accepted as a marine propeller blade section, is used for the pre-stator and turbine blade section. A CFD method, derived from the discretization of the RANS equations, is applied for the analysis of the designed turbine system. The design conditions of the turbine is confirmed by the CFD calculation. Turbine characteristic curve is calculated by the CFD method, in order to provide the performance characteristics at off-design operation conditions. The proposed procedures for the design of a propeller type rim-driven axial-flow turbine are established and confirmed by the CFD analysis.

• 한국해양공학회지
• /
• 제37권2호
• /
• pp.58-67
• /
• 2023

While extensive research is being conducted to reduce greenhouse gases in industrial fields, the International Maritime Organization (IMO) has implemented regulations to actively reduce CO₂ emissions from ships, such as energy efficiency design index (EEDI), energy efficiency existing ship index (EEXI), energy efficiency operational indicator (EEOI), and carbon intensity indicator (CII). These regulations play an important role for the design and operation of ships. However, the calculation of the index and indicator might be complex depending on the types and size of the ship. Here, to calculate the EEDI of two target vessels, first, the ships were set as Deadweight (DWT) 50K container and 300K very large crude-oil carrier (VLCC) considering the type and size of those ships along with the engine types and power. Equations and parameters from the marine pollution treaty (MARPOL) Annex VI, IMO marine environment protection committee (MEPC) resolution were used to estimate the EEDI and their changes. Technical measures were subsequently applied to satisfy the IMO regulations, such as reducing speed, energy saving devices (ESD), and onboard CO₂ capture system. Process simulation model using Aspen Plus v10 was developed for the onboard CO₂ capture system. The obtained results suggested that the fuel change from Marine diesel oil (MDO) to liquefied natural gas (LNG) was the most effective way to reduce EEDI, considering the limited supply of the alternative clean fuels. Decreasing ship speed was the next effective option to meet the regulation until Phase 4. In case of container, the attained EEDI while converting fuel from Diesel oil (DO) to LNG was reduced by 27.35%. With speed reduction, the EEDI was improved by 21.76% of the EEDI based on DO. Pertaining to VLCC, 27.31% and 22.10% improvements were observed, which were comparable to those for the container. However, for both vessels, additional measure is required to meet Phase 5, demanding the reduction of 70%. Therefore, onboard CO₂ capture system was designed for both KCS (Korea Research Institute of Ships & Ocean Engineering (KRISO) container ship) and KVLCC2 (KRISO VLCC) to meet the Phase 5 standard in the process simulation. The absorber column was designed with a diameter of 1.2-3.5 m and height of 11.3 m. The stripper column was 0.6-1.5 m in diameter and 8.8-9.6 m in height. The obtained results suggested that a combination of ESD, speed reduction, and fuel change was effective for reducing the EEDI; and onboard CO₂ capture system may be required for Phase 5.

• 분석과 대안
• /
• 제1권2호
• /
• pp.31-43
• /
• 2017

The article is devoted to the theoretical and practical analysis of Chinese global leadership. The concept of leadership is applied as a methodology, which involves identifying the main factors, such as strategic power, the attractiveness of political institutions, the ability to provide acceptable ideas and the presence of allies that contribute to a comprehensive analysis of the country's leadership potential. The authors also describe the relevance of Chinese global leadership and analyze its domestic, economic and international causes. Moreover, the ''Belt and Road'' initiative is defined as the main mechanism for providing the influence of China on the global level which is now being changed its quantitative component, namely the increasing attention to the security aspects of this initiative. In addition to that, it is important to note that China maintains its economic and political positions in Africa, Central Asia and South-East Asia. Africa has a special role in the Chinese ''Belt and Road'' initiative as a recipient of Chinese investments and a site for the deployment of China's naval facilities to protect the trade routes. On the regional level, China will strive to become a leader of the trade and economic processes in the Asia-Pacific region, the South China Sea and the North Korea nuclear program issues. The American factor in modern international relations, namely so-called "Trump factor", which means the U.S. withdrawal from the Trans-Pacific Partnership and the Paris Agreement, will cause demand for Chinese leadership in the Asia-Pacific region and in the world as well. However, in this case a number of questions arise: is China prepared for this? Is Beijing able to bear greater responsibility? Does China have the potential for this? The article concludes that China will not become global leaders in the next 20-30 years, because of internal (political reforms) and foreign policy reasons (doctrinal formulation of foreign policy initiatives, military-political and economic power, international posture and relations with other states). The authors believe that the implementation of Chinese leadership is possible not on the condition of confrontation between China and the United States, but on the establishing of constructive relations between these countries. The last meeting between Trump and Xi Jinping showed a trend for creating channels for dialogue between Beijing and Washington, which can become the basis for interaction. An important place in the work is given to the analysis of development and forecasting the evolution of Russian-Chinese and U.S.-China relations. As for Russia, Moscow should conduct a policy that will not allow it to become a ''junior partner'' of China.

• 해양안보
• /
• 제4권1호
• /
• pp.1-56
• /
• 2022

왜 인도는 해양으로 환경 설정된 인도태평양 지역의 핵심 행위자가 되었는가? 몇 가지 외부적 요인이 있지만, 인도의 경우 점점 더 험난해지는 지정학 및 안보 환경 속에서 인도의 지정학 및 해양 이권을 망라하는 전략지정학적 경계가 인도양 및 태평양에 걸친 자신의 영토를 넘어 빠르게 확장하고 있다. 따라서, 인도는 해양 군사력을 포함한 국력의 모든 면을 활용하여 이러한 전략적 무대 내의 사건에 영향을 미칠 능력을 갖춰야 한다. 이에 따라 인도 정부는 최근에 해상 안보 전략을 검토하는 데 많은 지적자본을 투자했다. 인도의 새로운 전략은 해상안보의 더 '소프트 (soft)'한 측면을 수반한 전체론적인 안보의 개념 및 전통적으로 '해양 전략에 대해 무지한 (sea-blindness)' 국가인 인도의 해양 인식을 되살리는 것을 전제로 하고 있다. 새로운 전략은 '안전한 바다 보장하기: 인도의 해상안보 전략'이라는 제목에서 분명히 보이듯이, 지금까지보다 더 지역 전체적, 포용적, 적극적인 접근법을 취하고 있다. 이 전략은 인도 연안 지역의 새로운 비전통적인 위협에 대한 커져가는 우려 및 군사적 억제력과 대비의 필요성을 다루는 한편, 전략적 자주성이라는 지속되는 원칙에 이끌린 다중 매개의 전략적 파트너십을 통한 것을 포함해 인도의 근접한 그리고 확장된 해양 주변부에서 호의적이고 규범에 기반한 온화한 환경을 추구하기 위한 인도의 필수적인 과제를 다룬다. 인도의 해상안보 전략에 대한 더욱 심오하고 포괄적인 이해를 위해 본 논문은 이 전략을 뒷받침하는 핵심적인 무언의 암시된 요소를 살펴본다. 이는 인도의 국가로서의 역사적, 문화적 진화; 전략적 지형; 지정학 및 안보에 대한 인식; 그리고 방위군에 대한 정치적 방향을 포함한다. 본 논문은 구체적으로 자연재해, 범죄 및 국가가 지원하는 테러에서부터 파키스탄과 중국이 가하는 위협에 이르는 해상위협에 대한 인도의 대응, 그리고 말라카 해협(Malacca Straits)의 동부에서 인도 해군이 구상 중인 역할을 다룬다. 또한, 인도의 해상안보 세력에 대한 조직개편 및 부대 기획의 측면도 분석한다.