• 소성∙가공
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• 제21권5호
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• pp.305-311
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• 2012

One of the main methods of building LNG tankers uses the Moss spherical tank design since it can be precisely analyzed with respect to reliability and safety of construction by stress analysis. Aluminum alloy 5083 is generally used in the Moss spherical tank design for the wall in constructing the LNG tanker. This aluminum alloy does not have low temperature brittleness, but has good corrosion resistance, good weldability, and excellent material properties for the application. The Moss spherical tank is constructed with several sections of A5083 thick plate with curved surfaces, which are welded together. It is essential to predict the amount of springback for the deformed thick plates in design to insure a reliable construction because the structure needs to be assembled into a perfect sphere. Unless the initial construction meets the design, there are additional processing costs for reworking to meet the specifications as well as a cost penalty paid to a consumer. In this paper, FE analyses were conducted to predict the amount of springback for various forming conditions and forming processes. The various forming processes were evaluated with respect to reducing springback and compared with the conventional forming process used for curved surfaces of thick Al plate.

• 소성∙가공
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• 제22권7호
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• pp.389-393
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• 2013

One of the most efficient designs for manufacturing LNG tank is the Moss spherical type because it has been validated through precise analyses with respect to reliability and construction safety by stress analysis. The Moss spherical tank is assembled with hundreds of Al thick plate patches that are deformed to curved shape at elevated temperature and welded together. It is essential to evaluate the amount of deflection in the Al5083 thick plate when the patch is transferred from the heating chamber to the forming die since the patch has a length of 12,000 mm and a thickness of 60 mm. Based on FE analysis results, a design procedure for minimizing deflection in Al5083 thick plate during transfer using a moving carrier is demonstrated in this paper.

• Journal of Advanced Marine Engineering and Technology
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• 제17권4호
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• pp.1-10
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• 1993

This paper introduces the outline of hull structure to the sorts of LNG carrier briefly. Especially, explains in detail for the insulation system of Moss Rosenberg Verft spherical tank type LNG carrier. It is not easy task to calculate exactly the temperature distribution of hull because of very complicated structure of hull. Therefore, in this paper by the adequate modeling of the Moss Rosengerg spherical tank type LNG carrier, a program is developed which calculate the temperature distribution of every hull and estimate the heat influx from every hull and output the BOR according to the variation of atmospheric conditions on boyage.

• Journal of Advanced Marine Engineering and Technology
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• 제22권1호
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• pp.28-34
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• 1998

This paper introduced the thermal characteristics of Moss Rosenberg Verft spherical tank type LNG Carrier. Especially described the temperature variation during cooling down condition. It is not easy task to calculate the temperature variation because of unsteady state condition. In this paper, computer simulation program is developed by using a Tomas Algorithm on unsteady state condition and compared with calculation results and experimental results on existing LNG Carrier voyage.

• 한국환경복원기술학회지
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• 제10권5호
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• pp.67-75
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• 2007

The purpose of this study was to pelletize to calendula and salvia seeds with peat moss as basic material for the efficient greening and vegetating of slopes and damaged areas. Also the pelletizing was compressed by spherical types that mixed basic fertilizer of N.;300 mg/l, P.;200 mg/l, K.;400 mg/g and plant growth regulator of A and NAA each 300PPM. Soil and soil surface seeding methods were researched to find the growing state of germination percent, germination date, germination force, length of leaf, number of leaf, width of leaf, length of plant, and etc. Comparing with controlled pelletizing, peat moss and +GA pelletizing treatments resulted in higher from two to three times as following growing states : length of leaves, number of leaves, width of leaves, length of plants, length of roots, fresh weights, and ratio of germination. Especially the two treatments above showed four more times effects than the +NNA treatment. Also their germinating date germinating force were earlier and stronger. The surface seeding method was superior to soil seeding.

• Animal Systematics, Evolution and Diversity
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• 제24권1호
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• pp.81-88
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• 2008

Two oxytrichid ciliates collected from the mosses and estuarine littoral in Korea were identified as Oxytricha longigranulosa Berger and Foissner, 1989 and O. marina Kahl, 1932. These species are reported for the first time from Korea. The description was based on living and protargol impregnated specimens. Diagnostic characters for each species are as follows. Oxytricha longigranulosa: Cell in vivo $80-115{\times}30-50{\mu}m$, mostly $90{\times}40{\mu}m$. Length/width ratio about 2.4/1. Cortical granules about $1{\times}1.5{\mu}m$ in size, colorless, arranged in short and discontinued longitudinal rows. Four frontoventral cirri. Adoral zone of membrane lies (AZM) covering 30-50% of cell length with 25-27 adoral membranelles (AM). Buccal area flat, typical Oxytricha pattern. Five transverse cirri, 19-23 right marginal cirri, 19-24 left marginal cirri, three caudal cirri, five dorsal kineties. Two macronuclear nodules 2 in number and spherical in shape, two micronuclei in number. Oxytricha marina: Cell in vivo $100-150{\times}30-60{\mu}m$. Cytoplasm colorless without cortical granules. Four frontoventral cirri. AZM covering 50% of cell length with 28-44 AMs, Buccal area flat, typical Oxytricha pattern. Five transverse cirri, 23-38 right marginal cirri, 19-25 left marginal cirri, three caudal cirri, five dorsal kineties. Two macronuclear nodules and spherical in shape, 1-5 micronuclei, mostly two in number.

• 대한기계학회논문집
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• 제18권4호
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• pp.986-996
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• 1994

Insulation system of LNG carrier has made important roles such as maintaining a proper Boil off Ratio(BOR) for the cargo and avoiding the excessive low temperature of the adjacent inner hull beyond the permissible limit. At the same time, safety and economy of the LNG transportation by the ship are connected with the performance of the insulation system. Also, thermal insulation system of LNG carrier is one of the most advanced technique with the structure analysis of tank, welding and assembling. In this study a computer program is developed to calculate the hull temperature distribution and BOR, which are important factors in thermal design for the Moss Rosenberg Verft spherical tank type LNG carrier. Detailed results for hhull temperature distribution close to LNG tank, BOR and the thickness effect of insulation material are reported in this paper in the range of standare design sea condition.

• Journal of Welding and Joining
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• 제18권4호
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• pp.28-37
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• 2000

In this paper the LNG vessel of the Moss type which is capable of lifting 15,261 tons is investigated in the view point of the pressure vessel preliminary design using the finite element method. The Pressure vessel design is based on the equivalent stress levels due to the internal pressure. The finite element model of the spherical pressure vessel is configured using 4 noded quadrilateral shell element. The finite element analysis program NASTRAN and ANSYS 5.5are implemented. The design is compared with the three kinds of the boundary condition : first, where the equator of the pressure vessel is fixed, and where the top and is fixed, and, the bottom end is fixed, respectively. A comparison is presented between the results obtained by the finite element model and by the prototype production model. Additionally just below position(case 1 & case 2) of equator ring was carried out by using ANSYS 5.5. The results show that the vessel design based on the stress is acceptable at the preliminary design.

• 식물병연구
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• 제17권3호
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• pp.402-404
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• 2011

2009년 9월 경기도 동두천시와 화성시 소재 농가에서 팔레놉시스 재배중 생육이 부진하고 하엽이 황화되며 심한 경우 뿌리와 기부가 마르고 식물체 전체가 말라죽는 증상이 발생하였다. 말라죽은 기부와 수태표면에 흰색 곰팡이 균사와 함께 둥근 형태의 적갈색 균핵이 관찰되었다. 균학적 특징으로 균사는 $25-30^{\circ}C$에서 가장 활발한 생장을 보였으며, 균핵은 갈색의 둥근형태로 직경은 1-3 mm 였다. 병원성 검정결과 병징이 접종 후 5일째 관찰되었으며 그 후 급속하게 진전되어 강한 병원력을 보였다. 팔레놉시스에서 발생한 병징과 병원균의 균학적 특징 및 병원성을 검정한 결과 이 증상은 Sclerotium rolfsii에 의한 흰비단병으로 동정되어 본 병을 팔레놉시스 흰비단병으로 명명하고자 한다.

• 식물병연구
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• 제16권3호
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• pp.320-322
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• 2010

2010년 2월 경기도 용인시 소엽풍란 재배농가에서 뿌리와 벌브가 심하게 마르고 식물체 전체가 말라죽는 증상이 나타났다. 마른 뿌리와 수태표면에 흰색 곰팡이 균사와 함께 뚜렷한 둥근 형태의 적갈색 균핵이 관찰되었다. 균학적 특징으로 균사는 $25{\sim}30^{\circ}C$에서 가장 활발한 생장을 보였으며, 균핵은 갈색의 둥근형태로 직경은 1~3 mm였다. 병원성 검정결과 발병이 초기부터 빠른 강한 병원성을 보였다. 균학적 특성 조사 결과 Sclerotium rolfsii에 의한 흰비단병으로 동정하였으며 본 병을 소엽풍란 흰비단병으로 명명하였다.