본 연구는 실내-외 우리가 있는 개방형 흑염소사에서 우리나라 5개월령 재래 흑염소를 대상으로 서열과 일주기 리듬이 하루 24시간 동안의 행동에 미치는 영향과 서열과 사료급여시간이 사료급여 후 30분 및 60분 동안의 행동에 미치는 영향을 조사하기 위해 수행하였다. 재래 흑염소의 행동은 CCTV를 사용해 녹화한 후 이들을 1분 단위로 측정하였고, 총 10개의 행동으로 분류하였다. 서열은 적대행동에 유의하게 영향을 미쳤으나 (p<0.05), 다른 행동에는 영향을 미치지 않았다. 일주기 리듬은 응립(p<0.05), 이동(p<0.01), 사료섭취(p<0.001), 적대행동(p<0.001), 비적대행동 (p<0.001), 사료탐색(p<0.05), 음수(p<0.001) 및 기타 행동(p<0.001)에 유의하게 영향을 미치는 반면 휴식(p>0.05)과 몸단장(p>0.05)에는 영향을 미치지 않았다. 서열과 일주기 리듬의 상호작용효과는 적대행동에만 유의하게 영향을 미쳤다(p<0.05). 서열은 사료급여 후 30분 동안 응립(p<0.05)과 사료섭취(p<0.05)에 유의하게 영향을 미쳤지만 다른 행동에는 영향을 미치지 않았다. 사료급여시간은 사료급여 후 60분 동안의 음수(p<0.05)에 유의하게 영향을 미쳤으나, 다른 행동에는 영향을 미치지 않았다. 서열과 사료급여시간의 상호작용효과는 모든 행동에 유의하게 영향을 미치지 않았다(p<0.05). 결론적으로, 서열, 일주기 리듬, 그리고 사료급여시간은 우리나라 5개월령 미성성숙한 재래 흑염소의 행동에 영향을 미치는 것으로 나타났다.
In this study, a high speed planing boat with 7.2 meters in length is developed as the beam larger about 10% by comparing with the general planing boat. The design speed of a boat is 30 knots (about 15.4 m/s) by using 150 hp outboard engine and the main material is FRP. The resistance performance related to the free running attitude as trim and sinkage is discussed and the wave patterns are observed to clear the relationship between the performance and wave characteristics by model test. The turning circle is estimated by Lewandowski´s equation. The results show that not only the wave pattern but also the free running attitude of the boat have the strong influence on a resistance performance. The boat needs smaller engine power and has more stable running attitude because of large sinkage and small variation of trim due to the large area for the lift force and light weight.
In this study, a high speed Rigid Inflatable Boat(RIB) with about 10 meters length is developed. Design speed of the boat is 30 knots (15.43 m/s) using 250 hp twin engines and main material is aluminum. Resistance performance related to the free running attitude as trim and sinkage are discussed and wave patterns are observed to make clear the relationship between the performance and wave characteristics using model test and CFD analysis. The results show that not only wave patterns but also free running attitude of the boat have a strong influence on resistance performance. CFD results including free surface give good relative tendency for effective power and the attitude comparing model test results. CFD analysis used in this study can be used at initial ship design stage of high speed boat.
In this study, a 30ft class high speed catamaran cruise boat is designed and resistance performances are investigated by model test at a circulating water tank. Design speed of the boat is 17knots(8.7m/s) and maximum speed is 20knots(10.3m/s) using 330ps twin engine. Each single bodies are designed unsymmetric planing hull considering high speed-length-ratio(Froude number) and wave interaction at inner part of the hull. Small size fins like chine are attached near free surface at each outside of the hull to separate wave along the hull side. The results show that the small chine plays a big role in separating the wave flowing along the hull. However, in the case of relatively heavy boat such as the developed hull, such a small power due to chine can not cause additional lift and cause resistance increase.
다양한 지질명소가 국내에 분포하고 있음에도 불구하고, 지질명소를 야외학습장으로 활용하지 못하고 있다. 이 연구의 목적은 상세한 지질조사를 통해 서낭바위 일대를 야외학습장으로 활용 가능하게 하는데 있다. 서낭바위는 강원도 죽왕면 송지호해수욕장 부근에 위치하며, 송지호에서 남동쪽으로 약 1km 떨어져 있다. 서낭바위 일대는 중생대 백악기 속초화강암과 이를 부정합으로 충적층이 덮고 있는 단순한 암석분포를 보인다. 서낭바위 일대는 초중등학생과 일반인들에게 화강암 암상, 구성광물, 풍화과정뿐만 아니라, 절리(N50E/80SW, N40W/84NW), 단층(N42W/83SW), 엽리(N32E/54SE), 암맥(N35E/40SE, N26W/63SW)과 같은 지질구조와, 토르, 타포니, 그루부, 나마와 같은 지형들을 학습할 수 있는 장소이다. 그러므로 서낭바위 일대는 작은 규모의 공간에서 여러 지질 및 지형학적 현상들을 학습하고 서낭바위의 성인을 토론할 수 있는 최적의 야외학습장이다.
The objective of this experiment was to investigate amino acids and mineral compositions of the four major muscles (LD: longissimus dorsi, PM: psoas major, SM: semimembranosus, and GM: gluteus medius) from Korean native black goat (KNBG). Five uncastrated male KNBGs of 36 months of age were commercially slaughtered and the four muscles were sampled to determine concentrations of myoglobin, collagen, amino acids and minerals. There were significant differences (p<0.05) in myoglobin and collagen content among the four muscles. Myoglobin content of PM was significantly higher (p<0.05) than those of SM and GM. Collagen content of SM was significantly higher (p<0.05) than that of LD. There were significant differences (p<0.05) in cystine and leucine concentrations among the four muscles, and PM had the highest concentrations of the two amino acids compared to other muscles (p<0.05). Also, there were significant differences (p<0.05) in K, P, Mg and Fe contents among the four muscles from KNBG. PM had the highest mineral content while the lowest mineral content was observed in LD. In addition, Fe contents of PM and GM were higher than those of LD and SM (p<0.05). These results indicated that amino acids and mineral content vary considerably with the anatomical location of muscles of Korean native black goat.
In this study, we analyzed the factors affecting the concentration of airborne asbestos fiber in the indoor and outdoor environment of a slate roofing house, and performed a health risk assessment of residents living in houses with slate roofs. Sampling was conducted at ten houses with slate roofs on 3 different days under different weather conditions. A high flow rate pump was used for sampling. The specimen was assessed using a phase-contrast microscope. The degree of risk of exposure to asbestos was assessed using EPA’s carcinogen risk assessment method. Asbestos fiber concentrations for slate roofing houses were 2.43 fiber/L inside and 2.46 fiber/L outside, respectively. The correlation between the indoor and outdoor asbestos fiber concentration was 0.486. But on both sides, the asbestos fiber concentrations did not exceed the standard (10 fiber/L) for ambient air in Korea. The factors affecting the concentration of asbestos fiber were year of construction (p<0.05), total roof area (p<0.05) and average wind velocity (p<0.01). According to EPA’s ELCR (Excess Lifetime Cancer Risk) on air pollution substances, a level of 1.0E-04~1.0E-06 should be maintained. However, the ELCR level of 6 out of 10 houses was over 1.0E-04. Therefore, a risk management plan for residents of slate roofing houses must be prepared immediately.
In this study, electric propulsion leisure boat with 9 meters length is designed and the performances are investigated by CFD analysis and model test. Maximum speed of the developed boat is 15knots(7.7 m/s) using 80Kw electric motor. Catamanan type hull form with slender body is adopted considering high Froude number and large deck area. Two kinds of hull forms are designed and the performances are compared in resistance point of view. Wave patterns are observed to make clear the relationship between resistance performance and wave characteristics. The results show that not only wave interaction due to shoulder waves but also stern waves have a strong influence on resistance performance and CFD analysis including free surface can give useful informations at initial ship design stage for high Froude number catamaran boat.
본 연구에서는 연안의 해저면에 누적된 퇴적오염물을 효율적으로 수거할 수 있는 저속 쌍동형 정화선에 대한 선수선형의 개념설계에 대해 수행하였다. 선형설계는 선체건조가 용이하도록 단순화하였으며, 쌍동선 선형의 선수 Water line, 선수각 등의 변화에 따른 저항성능의 영향을 검토하였다. Ansys CFX를 이용한 수치시뮬레이션과 회류수조에서의 모형시험결과와의 비교/분석 등을 통하여 선수부 선형변화에 따른 저항성능과 자유표면 유동특성 사이의 관계를 고찰하였으며, 그 결과 선수재 위치와 어깨부 체적의 선수부 이동에 따른 파형개선으로 조파저항이 감소하는 등 저항성능의 향상을 확인하였다.
해양레저 활동의 범위가 점차 원거리 항해로 확대되면서 거주가 가능한 크루즈보트가 각광받고 있다. 해양레저산업 선진국인 유럽, 북미의 경우 미려한 디자인, 인간공학적 구조 그리고 경량선체 소재 채택을 통한 연료효율 향상 등 크루즈보트의 설계와 제작에 있어 이미 경쟁력을 확보하고 있다. 반면, 국내의 경우 소형 레저보트 중심의 개발, 건조가 이뤄지고 있으며, 선체소재 또한 유리섬유강화복합재료(GFRP)가 대부분을 차지하고 있다. 본 연구에서는 원양항해가 가능한 50피트급 탄소섬유강화복합재료(CFRP) 선체 크루즈보트의 설계 및 특성에 관한 연구를 수행하였다. CFRP 선체 레저보트의 선형특성을 분석하여 설계선(MMU-C.B)의 선형을 제안하였으며, 이를 기반으로 CFRP 크루즈 보트의 설계모델을 구축하였다. 또한 GFRP 레저선박의 모형시험결과와 MMU-C.B 설계결과의 조선공학적 비교검토를 통해 설계선의 형상 그리고 저항 및 활주자세 특성을 분석하였다.
Recently, national attention on the regulations for carbon dioxide emission has risen. Thus, diverse attempts are being actively carried out to reduce the resistance of ships and to develop a new propelling system that reduces the emission of carbon dioxide. This study presents to induce a way to utilize the generated wind power for the electrical energy source of a ship’s lighting, air conditioning and heating by installing a compact wind power facility on the experiment target; a small size high-speed vessel. The vessel targeted for application is a 30ft high-speed leisure boat made of aluminum alloy. The wind power facility installed on the hull and the batteries that will be charged by the electric energy generated by the wind power system were considered at the designing stage of the boat. A new presumption equation for air resistance of wind turbines and efficient measures for management are suggested based on a model test that verifies the basic performance of the wind-powered leisure boat.
The ice tank is important facility to check the performance of the ship and offshore in ice condition before the construction. MOERI(Maritime & Ocean Engineering Research Institute) constructed ice model basin on the end of 2010. The ice technology to know the phenomena of ice near the ship and to estimate power of the ship in model scale is the main characteristic of the ice model basin. To achieve this goal in one ice sheet, making of test plan and feasibility check of test possibility have to review in the beginning stage of the every test. This paper describes the number of maximum resistance and self propulsion test in a sheet of level ice and proposes the methodology to optimize pack ice, rubble ice, brash ice and ice ridge test in MOERI ice tank. The feasibility of free running test to know maneuvering performance in ice field and some specific idea to measuring ice thickness and ice ridge shape was proposed.
Hull forms for catamaran type small fishing boat powered by electric motor are newly developed by experimental approaches. Model tests for two hull forms having different length are made at circulating water channel. Resistance performance and wave patterns are compared to carry out an analysis of the effect of extension of main body. The results show that the extension of main body can give better resistance performance above a certain velocity.
The feasibility study for reducing ship resistance was carried out. A thin plate was installed in front of bow to guide the air which was induced to the bottom just following to the hull surface when ship is running fast. To confirm the reduction of surface friction, model test in the high speed CWC and numerical simulation were implemented. The results show that the induced air to the bottom is increasing according to the increasing of air velocity and it plays an important role to reduce the frictional resistance.
The small catamaran leisure boat which is 4.1m length, 1.9m breadth and 0.7 ton displacement was designed. To decide optimum breadth, four sets of distances between hulls were considered. CFD analysis using FLUENT was performed to examine flow patterns, pressure distribution and wave height between two hulls. Model test at CWC in INHA Technical College was also carried out to get the resistance for final hull form at design speed 5 knots. The feature of flow pattern among four different distances between hulls were compared and discussed. The optimum breadth of design vessel was decided depending on the CFD results and comments of expertise that has experience on board the small demihull. The design procedure to choose optimum breadth, especially small change of the hull distance, using CFD was described in this paper
The corporate R&D(Research and Development) has a primary role of new product development and its potential is the most crucial factor to estimate corporate future value. However, its systemic inadequacies and inefficiencies, the shorten product life-cycl