• 한국산업융합학회 논문집
• /
• 제26권6_3호
• /
• pp.1305-1314
• /
• 2023

The global ship repair and modification market is expected to grow up to approximately $ 30 billion by 2025. Korea's shipbuilding industry is leading the world grounded on its international competitiveness in design and production technology. The reality, however, is that the ship repair and modification industry is centered on Gyeongnam, and there are only two to three ship repair workplaces that can repair large ships. Therefore, domestic ship repair companies target small and medium-sized ships mainly. This is because there are few workplaces equipped with a large dock in which large ships like LNG ships can be inspected regularly or repaired, complaints are severe for environmental problems, and related environmental regulations are so strict that it is very hard to obtain government approval for the extension of ship repair and modification workplaces or the opening of new shipbuilding sites. Besides, on account of the workers' high wages, few experts related, and higher ship repair price compared to that of Southeast Asia, most of the volume of repairing large ships including domestic LNG ships is being lost to Southeast Asian or Chinese markets. In this study, the work process and pre-work preparation process for ship hull (winch, windlass, hatch cover, ramp door, cargo gear, anchor chain) repair were analyzed and presented to foster domestic ship repair experts and revitalize related industries.

• 한국해양공학회지
• /
• 제23권5호
• /
• pp.9-14
• /
• 2009

The green water on deck has many harmful effects on the vessel in rough seas such as damages to hull structures, damages to cargos, increase of the downtime, decrease of the stability, and so on. Floating Production Storage and Offloading vessels (FPSOs) are operated in a specific location and are normally positioned to meet mostly head or bow waves in order to reduce the roll motions. But this makes FPSOs more vulnerable to green water around the bow region therefore the bow shape should be properly designed to mitigate the green water damage. In this paper, experimental results in regular head waves for three kinds of bow shapes are compared and some design considerations are proposed, with the building a database for computational fluid dynamics (CFD) validation in mind.

• 한국유기농업학회지
• /
• 제18권4호
• /
• pp.599-612
• /
• 2010

본 연구는 유기곡물사료와 농산가공부산물인 미강과 대두피를 이용한 유기배합사료를 제조하였으며, 관행사료와 비교하여 산양유의 생산성 및 경제성에 미치는 영향을 조사하기 위함이다. Saanen종 비유중기 4두를 유량, 착유일수 및 산차수를 고려하여 배치하였으며, 시험 설계는 2${\times}$3 crossover design으로 하였으며, 2주간 예비기간을 거쳐 본 시험을 실시하였다. 사료공급은 에너지 및 단백질 공급량에서 ME가 23 MJ/d, 그리고 CP는 382 g/d가 되도록 조정하였다. 전체 건물섭취량은 T1구(관행사료)와 T2구(유기사료)에서 각각 1,633g과 1,658g으로 비슷한 섭취량을 나타냈으며, 유량에서는 유의한 차이는 없었지만, T2구에서 1,816g/d로 T1구의 1,667g/d와 비교하여 약 150g/d 높은 유량 증가를 나타냈다. 유성분과 유지방 함량에서는 처리간 차이를 나타내지 않았으나, 지방산조성은 사료내 불포화지방산 함량이 풍부한 T2구에서 T1구보다 stearic acid(C18:0)와 linoleic acid(C18:2)가 유의하게 높았다. 또한 경제성 평가에서 1마리당 하루 150원의 소득증가를 나타냈으며 결과적으로 유기사료를 급여함으로써 농가소득에 기여할 것으로 판단된다.

• 대한조선학회 특별논문집
• /
• 대한조선학회 2013년도 특별논문집
• /
• pp.21-29
• /
• 2013

For the purpose of supporting Curved Blocks, pipe welding is commonly used on Curved panel. Typically, when it comes to attaching supporting pipe on heavy incurvated surface, it makes much loss in the process of design, cutting, welding. This paper gives proper methods to collecting problems and Core conflicts surrounding Support Pipe by using of TOC (Theory Of Constraints). Therefore drawing two solutions, pipe development program and NC generating from pipe development Data for Plate Cutting machine. It describes a process of erasing loss surrounding Support Pipe with "TOC Thinking process" and development of two programs in this paper.

• 대한조선학회논문집
• /
• 제55권2호
• /
• pp.136-143
• /
• 2018

3-D templates are produced to evaluate completeness of the shell plates during the forming process, which is an essential step for the ship production. They are mostly produced in advance during the detail/production design stage, but occasionally they are requested by the shell plate forming department, because it is impossible to predict accurately the necessities of them at the design stage. This results in a huge loss of man-hour and a bottleneck. In order to resolve this issue while reducing the dependence on other department, the process of manufacturing the 3-D templates needs to be automated. Therefore, this study proposes an automatic system that calculates the manufacturing information of the 3-D templates with only geometric information of the shell plates. The system considers the thickness and the cutting method of the parts of the 3-D templates and some options are provided to reflect the intention of the worker.

• 한국항해항만학회지
• /
• 제33권3호
• /
• pp.167-174
• /
• 2009

최근 해양 레저문화 확산에 따라 요트와 같은 레저선박의 설계기술이 요구되고 있다. 현재 까지 요트 설계 및 생산을 위한 국내 기술개발은 해양 레저 선진국에 비해 활발하지 않으나 최근에 요트 설계 및 생산기술기술의 발전으로 인하여, 관련 요소 기술의 개발이 필요시 되고 있다. 본 연구에서는 해양레저 선박으로서 쌍동선 요트에 대한 기본 구조 설계 및 구조 해석을 위한 기법을 제시한다. 요트와 같이 길이 50미터 이하 길이와 폭/비가 12보다 작은 소형 고속 선박의 강도 해석에 대한 규정이나 방법론은 아직 까지 선급 등에서 공식적으로 제안되지 않고 있다. 따라서 본 논문에서 부재의 스캔틀링은 DNV(Yachts, Design Principles, Design Loads, Hull Structural Design)기준과 KR(FRP선 규칙적용 지침)을 사용하였다. 또한, 구조해석 평가에 있어서는 ABS가이드 라인을 적금하여, 구조안정성을 평가하였다. 본 연구를 통하여, 38피트 보급형 쌍동선 요트의 실선 제작에 피드백 역할이 가능하게 되었다. 또한, 연구 결과는 앞으로 고속 쌍동형 요트의 구조설계 및 구조해석에 관련된 기본적인 자료로 유용하게 활용될 것으로 예상된다.

• 해양환경안전학회지
• /
• 제28권7호
• /
• pp.1267-1273
• /
• 2022

최근 한국 조선업계가 세계 선박 발주 물량의 대부분을 수주하고 있지만, 생산 현장에서는 인력난으로 생산공정 차질을 겪고 있다. 오랜 조선업 불황으로 일감과 임금 모두 줄어든 탓에 근로자들이 조선소를 떠났기 때문이다. 수주가 증가한 주요 요인은 카타르 LNG선 대량 발주였으며, 선박에 요구되는 기술 사양이 복잡해지는 상황도 유리하게 작용하고 있다. 선박은 계약한 인도 시점이 무엇보다도 중요하기 때문에, 조선소의 주요 공정 중 도크 진수 계획이 무엇보다도 중요한 관리 아이템이다. 도크에서 건조되는 구조물은 의장 작업을 남긴 선체 혹은 완성형 선박일 수 있으며, 때에 따라서 선체의 일부 블록 수준일 경우도 많다. 진수 시, 선체는 유체력에 의한 호깅(hogging) 혹은 새깅(sagging) 모멘트 영향을 받게 되고, 블록 연결부의 구조강도에 대한 안전성 확보가 무엇보다도 중요하다. 정상적인 공정이라면 연결 부재는 용접을 끝낸 상태에서 진수하지만, 실제 조선사에서는 도크 일정을 준수하기 위하여 구조 안전성이 확보되는 조건에 대한 빠른 의사결정이 필요하다. 본 연구에서는 앞서 언급한 문제점들을 엔지니어링 관점에서 합리적으로 판단하기 위하여 휨 응력평가법과 유한요소해석 모델링을 사용한 상세 해석법과 적용성을 분석하였다. 논문에서 언급된 주요 내용은 향후 유사 구조 강도 평가의 진행 시 좋은 사례로 활용될 수 있을 것으로 생각한다.

• Nuclear Engineering and Technology
• /
• 제48권4호
• /
• pp.893-905
• /
• 2016

Numerous advanced reactor concepts have been proposed to replace light water reactors ever since their establishment as the dominant technology for nuclear energy production. While most designs seek to improve cost competitiveness and safety, the implausibility of doing so with affordable materials or existing nuclear fuel infrastructure reduces the possibility of near-term deployment, especially in developing countries. The organic nuclear concept, first explored in the 1950s, offers an attractive alternative to advanced reactor designs being considered. The advent of high temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept even more viable today. We present a simple, cost-effective, and safe small modular nuclear reactor for offshore underwater deployment. The core is moderated by graphite, zirconium hydride, and organic fluid while cooled by the organic fluid. The organic coolant enables operation near atmospheric pressure and use of plain carbon steel for the reactor tank and primary coolant piping system. The core is designed to mitigate the coolant degradation seen in early organic reactors. Overall, the design provides a power density of 40 kW/L, while reducing the reactor hull size by 40% compared with a pressurized water reactor while significantly reducing capital plant costs.

• Asian-Australasian Journal of Animal Sciences
• /
• 제13권10호
• /
• pp.1407-1413
• /
• 2000

Oil palm frond (OPF) is a new non-conventional fibrous feed for ruminants. Evaluation on the nutritive values and digestibility of OPF was carried out using goats. In a completely randomised design, 20 local male goats were assigned to evaluate fresh and different types of processed OPF. A 60 day feeding trial was done to determine the digestible nutrient intake of fresh, ensiled and pelleted OPF and its response on live weight gain of goat. The pelleting of OPF increased (p<0.05) intake compared to fresh or ensiled OPF. The OPF based mixed pellet (50% OPF with 15% palm kernel cake, 6% rice bran, 6% soybean hull, 15% molasses, 2% fishmeal, 4% urea, 1.5% mineral mixture and 0.5% common salt) increased (p<0.05) nutrient intake, digestibility and reduced feed refusals. The mixed pellet also increased digestible dry matter intake (DDMI) and digestible organic matter intake (DOMI) at 80% and 63% level respectively than the fresh OPF. The increased digestible nutrient intake on the OPF based mixed pellet, resulted in increased live weight gain of goats. Furthermore, OPF has a good potential as a roughage source when it is used with concentrate supplement. OPF based formulated feed in a pelleted form could be used as a complete feed for intensive production of goat and other ruminants.

• 대한조선학회논문집
• /
• 제53권4호
• /
• pp.275-281
• /
• 2016

One of the most important things for quality to meet ship-production schedule is an accuracy control. A ship is assembled by welding through whole production process, so it is important that loss by correction will not happen as much as possible by using some engineering skills like reverse design, reverse setting and margin for thermal shrinkage. These efforts are a quite effective in fabrication stages, but not in erection stages. If a ship block which consists of common steel is exposed to directional solar radiation, its dimensional accuracy will change high as time by its thermal expansion coefficient. Therefore, the measuring work would be often done at dawn or evening even with having a very accurate device. In this study, an FE analysis method is developed to solve this problem. It can change measured data affected by solar thermal distortion to ones not, even though ship-block is measured at an arbitrary time. It will use the time when measuring, the direction of block and the weather record by satellites. It is confirmed by a comparison between measured data of a ship-block and the result by suggested analysis method. Furthermore, a pre-processing system is also developed for fast application of the suggested analysis method.