• 대한기계학회논문집B
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• 제30권7호
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• pp.707-714
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• 2006

A numerical analysis study has performed in terms of fluid dynamics to identify the wall thinning generated in the main feedwater isolation valve body of a nuclear power plant. To review the relations between flow characteristics and the wall thinning induced by flow accelerated corrosion (FAC), numerical analysis using FLUENT code and ultrasonic tests (UT) were performed. The local velocities according to the analysis results were compared with the distribution of the measured wall thickness by ultrasonic tests. The comparison results show that the local velocity in the x-direction had no correlation with the wall thinning but the local velocity in the y-direction and turbulence intensity had a great influence on that. These results provide a good match to those of the previous studies - locations colliding vertically against components undergo severe wall thinning. These results may be utilized to the design modification and the wall thinning management for main feedwater isolation valves for preventing the wall thinning degradation.

• Nuclear Engineering and Technology
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• 제32권1호
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• pp.67-76
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• 2000

Significant wall thinning due to flow accelerated corrosion(FAC）was recently reported in main feedwater pipes in 3 Korean pressurized water reactor(PWR) plants. The main feedwater pipes in one plant were repaired using overlay weld method at the outside of pipe, while those in 2 other plants were replaced with new pipes. In this study, the effect of the wall thinning in the main feedwater pipes on piping integrity was evaluated using finite element method. Especially, the effects of both the overlay weld repair and the stress concentration in notch-type thinned area on the piping integrity were investigated. The results are as follows : (1) The piping load carrying capacity may significantly decrease due to FAC. In special, the load carrying capacity of the main feedwater pipe was reduced by about 40% during about 140 months operation in Korean PWR plants. (2) By performing overlay weld repair at the outside of pipe, the piping load carrying capacity can increase and the stress concentration level in the thinned area can be reduced.

• 건축역사연구
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• 제17권4호
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• pp.25-42
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• 2008

The Gyeongbok Palace was completed during the reign of King Taejo and King Sejong in the early Joseon Dynasty. The most remarkable spacious feature of the palace is that it has an inner palace wall without an outer palace wall. The absence of the outer palace wall had its origin in the palace of the late Goryeo Dynasty which did not provide the outer palace wall. Gwanghwamoon was the main gate of the palace, and the office buildings of the Six Ministries were arranged on the right side in front of the main gate. A wide road called Six Ministries Avenue was made between the builidings. The avenue was completed during the reign of the third king of Joseon, Taejong, and it was assumed that this arrangement was influenced by the government office arrangements of Nanjing, the early capital city of the Ming Dynasty. Gwanghwamoon held national rituals as well as the civic and military state examinations nations in front of the gate. The avenue was decorated with flowers and silks when kings and the royal families, or Chinese envoys enter the gate, and the civilians watched the parade, Because there was no outer palace wall, all the events held at Gwanghwamoon and the Six Ministries Avenue ware opened to the public, it was the unique feature of Gyeongbok Palace that the palaces of Goryeo dynasty and China did not have.

• 정보처리학회논문지B
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• 제10B권7호
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• pp.837-846
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• 2003

본 연구에서는 아파트의 설계도면을 처리의 대상으로 하고 있다. 이러한 아파트 도면은 굵고 평행한 두 개의 선으로 표현되는 주벽과 심볼(문, 창, 베란다. 타일 $\cdots$), 치수선(Dimension Line), 치수보조선, 여러 가지 수치를 나타내는 숫자(치수)와 문자 등으로 구성되어 있다. 본 연구에서는 이러한 아파트 도면 내에서 아파트 건물의 골격을 이루는 주벽을 인식하는 방법을 제시하고 있다. 이를 위해서 가는 라인을 제거하고 굵은 라인만을 남기는 이진화 방법을 사용하여, 이러한 라인들을 벡터화하고, 주벽의 존재위치를 한정하였다. 이를 이용해 치수보조선을 구하고 찾은 피수보조선을 이용하여 주벽을 검출하고, 찾아진 주벽에 연결되는 다른 주벽으로 영역을 확장해 나가는 방법을 구현하였다. 마지막으로, 주벽사이에 있는 창문은 비록 주벽이 아닌 창문 심볼로 표현되어 있더라도 주벽으로 인식해야 하기 때문에, 찾아진 주벽을 이용해 이들 주벽사이에 존재하는 창문을 찾는다. 실험결과 인식률에서 본 연구에서 제시하는 방법이 96.5%의 인식율을 나타내어 Karl Tombre 연구팀의 방법 90.7%보다 5.8% 더 우수하게 나타났고, 오인식의 수도 작게 나타났다.

• 자원환경지질
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• 제7권2호
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• pp.45-62
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• 1974

Scheelite deposits in Sangdong mine are divided into three parallel vein groups, namely "Hanging-wall vein" which is located in the lowest parts of Pungchon Limestone, "Main vein" the most productive vein replaced a intercalated limestone bed in Myobong slate, "Foot-wall veins" a group of several thin veins parallel to main vein in Myobong slate. Besides the above, there are many productive quartz veins imbedded in the above veins and Myobong slate. Molybdenite and wolframite are barren in the former three veins group but associates only in quartz veins. Both main vein and foot-wall veins show regular zonal distribution, quartz rich zone in the center, hornblende rich zone surrounding the quartz rich zone and diopside rich zone in the further outside to the marginal parts of the vein. According to the distribution of three main minerals, quartz, hornblende and diopside the main vein can be divided into three zones which are in turn grouped into 7 subzones by distinct mineral paragenesis. They are summerized as follows: A. Diopside rich zone: 1. garnet-diopside.fl.uorite subzone 2. diopside-zoisite-quartz subzone 3. diopside-plagioclase subzone B. Hornblende rich zone: 4. hornblende-diopside-quartz subzone 5. hornblende-quartz-chlorite subzone 6. hornblende-plagioclase-quartz.sphene subzone C. Quartz rich zone: 7. quartz-mica-chlorite subzone The foot-wall veins can similarly be divided by mineral paragenesis into 3 zones, 6 subzones as follows: A. diopside rich zone: 1. garnet-diopside-quartz.fl.uorite subzone 2. garnet-diopside-wollastonite subzone B. Hornblende rich zone: 3. quartz-hornblende-chlorite subzone 4. hornblende-plagioclase-quartz subzone 5. hornblende-diopside-quartz subzone C. Quartz rich zone: 6. quartz-mica subzone The hanging-wall vein is generally grouped into 9 subzones by the mineral paragenesis which show random distribution. They are as follows: 1. diopside-garnet-fluorite subzone 2. diopside-zoisite-quartz subzone 3. diopside-hornblende-quartz-fluorite subzone 4. wollastonite-garnet-diopside subzone 5. hornblende-chlorite-quartz subzone 6. quartz-plagioclase-hornblende-sphene subzone 7. quartz-biotite subzone 8. quartz-calcite subzone 9. calcite-altered minerals subzone Among many composing minerals, garnet specially shows characteristic distribution and optical properties. Anisotropic and euhedral grossularite is generally distributed in the hanging wall vein and lower parts of the main vein, whereas isotropic and anhedral andradite in the upper parts of the main vein. Plagioclase (anorthite) and sphene are distributed ony near the foot-wall side of the aboveveins. wollastonite is a characteristic mineral in upper parts of the hang-wall vein. Molybdenite is distributed in the upper parts of quartz veins and wolframite in lower parts of quartz veins.

• 보존과학회지
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• 제23권
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• pp.53-65
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• 2008

안동 봉정사 대웅전 후불벽체의 제작기법 특성을 규명하기 위하여 벽체의 구조 및 재료적 특성을 자연과학적 방법을 활용하여 조사 분석하였다. 연구결과, 벽체의 구조 및 재료학적 특성이 규명되었으며 제작기법이 거시적인 차원에서 확인되었다. 대상벽체는 목부재를 중심으로 대칭을 이루는 맞벽의 구조를 취하고 있으며 초벽, 중벽, 화벽으로 구성되는 일반적인 벽체의 구조적 경향을 따르고 있는 것으로 판단된다. 제작과정에 따라 형성된 각각의 층위는 재료 및 제작기법의 차이를 보이며, 대체적으로 상부 층위일수록 세립의 물질이 사용된 것으로 확인되었다. 벽체의 형성에 사용된 주재료들과 첨가물질의 배합은 벽체내구력 및 보존력 향상에 기여한 것으로 판단되며, 보존력의 원인이 되는 물질간의 상호작용과 제작자의 세부적인 기법적 효과로 견고한 벽체가 형성된 것으로 보인다.

• Structural Engineering and Mechanics
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• 제51권3호
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• pp.361-375
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• 2014

The main aim of this paper is to investigate the relationship between thickness and height of the axially symmetric cylindrical reinforced concrete (RC) walls by the help of a meta-heuristic optimization procedure. The material cost of the wall which includes concrete, reinforcement and formwork, was chosen as objective function of the optimization problem. The wall thickness, compressive strength of concrete and diameter of reinforcement bars were defined as design variables and tank volume, radius and height of the wall, loading condition and unit cost of material were defined as design constants. Numerical analyses of the wall were conducted by using superposition method (SPM) considering ACI 318-Building code requirements for structural concrete. The optimum wall thickness-height relationship was investigated under three main cases related with compressive strength of concrete and density of the stored liquid. According to the results, the proposed method is effective on finding the optimum design with minimum cost.

• 열처리공학회지
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• 제6권4호
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• pp.243-248
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• 1993

A Circulating Fluidized-Bed (CFB) with an internal nozzle and a partition wall was proposed. The technique of fluidization is related to operations first used commercially in the fields of metallurgical and mechanical engineering such as the heat treatment of metals and power station combustors. In the modified CFB, an internal nozzle and a partition wall were additionally set in the main bed. This cold mode CFB apparatus made of acrylic resin; the main bed is 1,500mm high and 100mm in the inner diameter, the internal nozzle is 130mm high and 10mm in the inner diameter, and the partition wall is 7mm thick and 100mm in the diameter. Glass beads of $89{\mu}m$ in the mean diameter were employed as bed materials.

• 헤리티지:역사와 과학
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• 제54권4호
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• pp.4-21
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• 2021

본 연구는 조선시대 건축 공사 기록인 영건의궤에서 조선 후기 건물에 구성되었던 벽의 명칭과 유형을 살펴보고, 종묘 정전과 영녕전에 사용된 벽에 대해 고찰하는 데 그 목적이 있다. 연구의 결과는 다음과 같다. 첫째, 벽의 명칭은 성격에 따라 방향·위치, 형상·기능, 재료, 복합 등 네 가지 유형으로 구분할 수 있으며 벽 앞에 성격을 의미하는 단어가 합쳐진 합성어로 사용되었다. 둘째, 벽의 유형 중 재료와 관련된 일부 벽은 사용 시기에 차이가 있음이 확인되었다. 18세기 이후 토벽의 사용은 줄고 목벽(판벽), 지벽의 사용이 많은 것으로 확인된다. 셋째, 종묘 정전과 영녕전의 벽은 흙벽과 화방벽이 사용되었으며, 고주열 중인방 상부는 흙벽으로, 외부는 화방벽으로 구성되었다. 화방벽은 종묘 정전의 경우 기둥까지를 포함한 일체화된 모습으로 설치된 반면, 영녕전의 경우는 기둥과 기둥 사이에만 설치되었다. 넷째, 갑벽은 의궤 내 사용된 용례들과 현재 건물의 비교를 통해 '종묘 내 건축물 구성 시 사용된 중인방 상부에 설치한 벽'으로 정의할 수 있다. 본 연구는 익숙한 까닭에 연구가 미비했던 벽을 중심으로 조선 후기에 사용되었던 벽의 명칭들과 용례를 기록과 실제 건물의 비교를 통해 살펴보고 갑벽의 정의를 밝히기 위해 시도하였다는 점에 의의를 둘 수 있다.

• Advances in concrete construction
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• 제11권1호
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• pp.33-43
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• 2021

A new type of composite insulated concrete sandwich wall (ICS-wall), which is composed of a triangle truss steel wire network, an insulating layer, and internal and external concrete layers, is proposed. To study the mechanical properties of this new ICS-wall, tensile, compression, and shearing tests were performed on 22 specimens and tensile strength and corrosion resistance tests on 6 triangle truss joints. The variables in these tests mainly include the insulating plate material, the thickness of the insulating plate, the vertical distance of the triangle truss framework, the triangle truss layout, and the connecting mode between the triangle truss and wall and the material of the triangle truss. Moreover, the failure mode, mechanical properties, and bearing capacity of the wall under tensile, shearing, and compression conditions were analyzed. Research results demonstrate that the concrete and insulating layer of the ICS-wall are pulling out, which is the main failure mode under tensile conditions. The ICS-wall, which uses a graphite polystyrene plate as the insulating layer, shows better tensile properties than the wall with an ordinary polystyrene plate. The tensile strength and bearing capacity of the wall can be improved effectively by strengthening the triangle truss connection and shortening the vertical distances of the triangle truss. The compression capacity of the wall is mainly determined by the compression capacity of concrete, and the bonding strength between the wall and the insulating plate is the main influencing factor of the shearing capacity of the wall. According to the tensile strength and corrosion resistance tests of Austenitic stainless steel, the bearing capacity of the triangle truss does not decrease after corrosion, indicating good corrosion resistance.