• 한국정밀공학회지
• /
• 제22권2호
• /
• pp.148-155
• /
• 2005

This study was carried out to analyze the effect of direction of wind load and machinery house location on the stability of container crane loading/unloading a container on a vessel. The overturning moment of container crane under wind load at 50m/s velocity was estimated by analyzing reaction forces at each supporting point. And variations of reaction forces at each supporting point of a container crane were analyzed according to direction of wind load and machinery house location. The critical location of machinery house was also investigated to install a tie-down which has an anti-overturning function of container crane at the land side supporting point.

• 한국농공학회지
• /
• 제18권4호
• /
• pp.4265-4273
• /
• 1976

1. Fine aggregates of concrete are very important for the construction works and construction cost determination. Most of fine aggregates are from the river sand, but the amount of storage in the river side is steadily decreasing due to continuous construction works. Therefore, another source of fine aggregates is needed to meet increasied demand of sand. 2. Beach sand is a possible source of fine aggregates. But rust of steel bar is caused by CL-chemical of beach sand. Therefore, desalinization of beach sand is requested to get durable reinforced concrete. Economical methods of desalinization are as follows. (a) Flooding and drainage method. (b) Washing of beach sand with water supply and mixing. (c) Spreading of beach sand on the land and leaching by rain water for a few month. 3. Hardening of concrete with beach sand is accelerated due to salt, Thus early stage strength increase leads to make cracks. Also later stage strength decreases and durability becomes worse. By using appropriate admixture, the quality of concrete can be improved.

• 산업기술연구
• /
• 제9권
• /
• pp.3-19
• /
• 1989

Shoreline have been changed from time immemorial continuously, three-quarters of the population of the world live by the sea. It is not too much to say that all of us who live in Han penisular live by coastal zone because we can reach in the beach within only for hours. In this way effectual use and menagement of coastal zone is very importent problems in side of protection of marine resources as well as land use. But it has problems which change of shoreline have to be surveyed and to be predictived. This study the pattern and characteristics of the East sea coast including investigations of the shoreline changes of the East sea. This report gives a description of the method for implementing the seawall boundary condition in the shoreline change numerical model. Such analytical solutions can provide a simple and economical means to make a quick qualitative evaluation of shoreline response under a wide range of environmental and engineering conditions.

• 천문학회보
• /
• 제37권2호
• /
• pp.105.1-105.1
• /
• 2012

Moon and Mars have been explored by landers and rovers. Apollo missions landed five times on Lunar surface, and various rovers, including Curiosity landed and explored Mars. The selection of landing site have to be considered engineering and scientific side: the landing site to be available to land stably? the obstacle is not around the rover such as rocks and pothole? the landing site is valuable with scientific? And then landing site have to be the place which is satisfied two objects. We search the information about landing sites of Moon and Mars, and compile the conditions of landing sites. We expect that these data are useful when the landing site of Moon or Mars for Korean mission is selected.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1990년도 가을 학술발표회 논문집
• /
• pp.157-162
• /
• 1990

Recently, the multistory building construction of reinforced concrete has increased year by year, trended to be high rise in the view of effective land use planning, costing down of building construction and residential conditions. For this urgent need in construction industry, research and development of workability and engineering properties of high strength concrete has been closed up as one of the big world wide problems to be solved reasonably. It is aim of this study to provide the fundamental data the workability and engineering properties of steel-fiber reinforced high strength concrete containing silica-fume and fly-ash comparing with plain concrete for the practical use and research data accumulation in the side of development of new material in the building construction.

• 한국환경복원기술학회지
• /
• 제9권3호
• /
• pp.51-58
• /
• 2006

The purpose of this research presents a method to position and makes the structure for eco-corridors reasonably with collectable analysing results of various effects shown in mammals' road-kill at 429 points. Target animals of this research are Leopard cat, Siberian weasel, Raccoon dog, Korean hare, Eurasian red squirrel, Siberian chipmunk and Water deer. The results derived from the empirical analysis on the contents above are followed. First, according to the results as for Leopard cat road kill analysis, which is designated as Endangered Species Class II, the eco-corridor might be located at near village having stead food in order to decrease the frequencies of road-kill, because its road kill points were mainly collected at 4 lane hilly road with mountain-road-farm area geological type of. Second, because Siberian weasel's road kill was detected at 2 lane hilly road with mountain-road-stream geological type, the eco-corridor might be located at near a mill to decrease road-kill frequencies. Third, the road-kill frequency of Eurasian red squirrel can be reduced when the eco-corridor is located at the area across coniferous tree near 4 lane west sea freeway with mountain-road-mountain. Fourth, the road-kill of Raccoon dog can be reduced when the eco-corridor is located at 4 lane mountain road or hilly road with the geological type having farm land-road-mountain(stream). Fifth, Korean hare's road-kill can be reduced when the eco-corridor is located at grass land across ridge line of mountain, because wild rabbit road kill was happened at 4 lane mountain road or 2 lane mountain road(mountain-road-mountain). Sixth, As for Siberian chipmunk, the eco-corridor might be located at the side slope of mountain road at 2 lane mountain road under the speed of 60km/h with mountain-road-mountain. Seventh, For Water deer, the eco-corridor might be located at 4 lane hilly road with mountain-road-farm land. As for Common otter, Amur hedgehog, Yellow-throated marten, Weasel, it is difficult to specify the proper site of eco-corridor due to the lack of data. Eco-corridors for carnivores might be well located at 4 lane hilly road or 2 lane hilly road with mountain-road-farm land, and the track for herbivores might be well located as a overhead bridge on mountain-road-mountain type across mountains. In order to position eco-corridors for wildlife properly, we have to research animal's behavior with ecological background, and to consider the local uniqueness and regularly collect the empirical road-kill data in long term 3 to 5 year, which can be the foundation for the more suitable place of wild life eco-corridors.

• 한국농공학회논문집
• /
• 제57권6호
• /
• pp.21-33
• /
• 2015

Recently, the Korean government announced a new development plan for a large-scale greenhouse complex in reclaimed lands. Wind environments of reclaimed land are entirely different from those of inland. Many standard books for ventilation design didn't include qualitative standard for natural ventilation. In this study, natural ventilation rates were analyzed to suggest standard for ventilation design of venlo type greenhouse built on reclaimed land. CFD (Computational Fluid Dynamics) simulation models were designed according to the number of spans, wind conditions and vent openings. The wind profile at a reclaimed land was designed using ESDU (Engineering Sciences Data Unit) code. Using the designed CFD simulation model, ventilation rates were computed using mass flow rate and tracer gas decay method. Additionally computed natural ventilation rates were evaluated by comparing with ventilation requirements. As a result of this study, ventilation rates were decreased with increasing of the number of spans. Ventilation rates were linearly increased with increasing of wind speed. When the wind speed was $1.0\;m{\cdot}s^{-1}$, only side vent was open and wind direction was $45^{\circ}$, homogeneity of ventilation rate at 0~1 m height is the worst. Finally, chart for computing natural ventilation rate was suggested. The chart was expected to be used for establishing standard of ventilation design.

• 토지주택연구
• /
• 제6권4호
• /
• pp.195-213
• /
• 2015

전세수급 불균형 및 그에 따른 전세가격 상승, 임대인의 월세 선호로 전세 비중이 줄고 보증부 월세 비중이 급격히 늘어나는 등 주택 임대차시장 패러다임의 일대 변화가 나타나고 있다. 본 연구는 2014년 12월 임차인(일반임차인, LH임대주택 임차인), 임대인, 공인중개인 등 시장참가자를 지역, 거주 유형별로 1,150여 명의 설문조사 결과를 시행하였다. 설문조사 분석결과 시장참여자 모두 전세에서 월세로의 구조변화가 더욱 심화될 것으로 전망했으며 전세가격 상승 이유는 임차인, 임대인, 중개인 모두 집주인의 월세 선호와 전세물량 부족을 응답하였다. 주거안정 및 전세가격 안정을 위한 대책으로는 임차인, 임대인, 중개인 모두 공공임대주택 공급 확대를 최우선으로 꼽았으며, 이 외에 민간임대주택 활성화, 전세금 대출제도 확대, 임대료 보조지원 등을 지목하였다. 고소득층의 전월세시장에 대해 공공이 지나친 개입하기 보다는 시장의 자율성에 맡기는 것이 바람직하며 저소득층에 대해서는 시장원리에 맡기기보다는 장기공공임대주택의 공급확대를 통하여 중장기적으로 전월세 시장을 안정을 기하는 방안이 요구된다.

• 한국해양환경ㆍ에너지학회지
• /
• 제7권4호
• /
• pp.207-215
• /
• 2004

최근 육지역에서 새로운 넓은 용지의 확보가 어려워짐에 따라, 이를 해역에서 찾으려 하는 경향이 나타나고 있으며, 이러한 개발은 개발이 예정된 주변 연안역에 광범위한 해빈변형문제를 야기할 위험이 있다. 따라서 인공섬 등과 같은 외해 구조물을 계획할 경우에는 구조물 건설이 인접 해역의 해빈변형에 미치는 영향을 사전에 적적히 예측할 필요가 있다. 본 연구는 연안역의 침식을 포함한 해빈변형예측모델의 개발을 목적으로, 3차원 이동상 실험을 수행하여 외해 구조물 배후의 표사이동 양상을 분석한 것이다. 실험을 통하여, 외해 구조물 배후의 해빈변형에서 해안선측과 수심역의 해빈변형 기구가 상호 독립되어 있음을 밝혔다. 구체적으로는 소상대를 포함하는 해안선측은 등심선에 대한 파의 입사방향에 대응하는 표사이동이 탁월하며, 수심역에서는 파의 왕복운동에 의한 소류 및 부유사가 해빈류에 지배되어 이동하고, 양자는 해빈에서 형성되는 부분 중복파와 연관된 특정 경계를 기준으로 서로 분리되어 이동함을 규명하였다. 이들 실험 결과는 해빈변형모델의 개발에서 중요한 열쇠를 제공하리라 사료되며, 또한 기 개발된 모델의 검정자료로써도 활용될 수 있으리라 기대된다.

• 농업과학연구
• /
• 제23권1호
• /
• pp.13-24
• /
• 1996

널말뚝을 이용하여 연약지반을 굴착할 때 굴착단계에 따른 지반의 변위 변형 및 안정성을 분석하여 다음과 같은 결론을 얻었다. 1. 수평방향의 변위는 버팀대 설치전에는 굴착면 상부에서 크게 나타났으나, 버팀대 설치 후는 굴착저면의 아래쪽으로 이동되면서 집중되는 현상을 나타냈다. 2. 버팀대 설치후에 널말뚝의 변위는 설치 전보다 1/2정도로 급격히 감소함을 나타냈고, 지반의 안정한 굴착깊이의 한계는 2단 버팀대 설치후는 GL-8.0m정도로 나타났다. 3. 최대전단변형은 굴착깊이에 따라 점차로 증가하였고, 또 굴착저면에서 나타나는 전단변형에 의한 국부적인 파괴가능성은 버팀대로 보강함으로써 감소시킬 수 있었다. 4. GL-7.5m에서 널말뚝의 최대수평변위는 탄소성법에서는 굴착깊이의 0.2%, 유한요소법에서는 0.6%로 나타났으며, 굴착저면부근에서 최대변위를 나타냈다. 5. 해석모델지반에서 근입깊이에 대한 안전성을 확보하기 위해서는 버팀대 1단 설치의 경우는 D/H가 0.89이상, 2단설치의 경우는 D/H가 0.77이상이 될수 있도록 근입깊이를 확보하여야 할 것으로 판단된다. 6. 근입깊이에 대한 안전율과 D/H와의 관계에서 버팀대 1단 설치의 경우는 Fs = 0.736(D/H) + 0.54, 버팀대 2단 설치의 경우는 Fs = 0.750(D/H) + 0.62의 관계식을 나타냈다.