• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.27-34
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• 2001

This paper discussed the shape effect of ceramic support carrier in order to facilitate biomass immobilization. The shape of ceramic support carrier was modified hollow pipe type into hollow gear type. After seeding, microorganisms were attached in crevices where protection from shear forces or surfaces where easy to contact with support carrier surface. In case of hollow gear type carrier, initial attachment rate was faster than that of hollow pipe type and obtained thick biofilm. Synthetic wastewater(COD:75~880 mg/L, organic loading rate:0.36~4.22 kgCOD/㎥.d) was treated aerobic fixed bed biofilm reactor where 100% of the volume was filled with the ceramic carrier. COD removal efficiency of reactor filled with gear type support carrier was a little high withing 70 days, and then showed similar removal efficiency. It was found that highly loaded operation with up to 4.22 kgCOD/㎥.d was possible in both reactor. Total biomass amounts of pipe type was higher than gear type, however, attached biomass of gear type was higher than that of pipe type.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.314-319
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• 2010

This paper represents the results of study on Extra High Voltage Power Cable Connection System Development. The purpose is to evaluate structural safety by numerical analysis for the relaxation of electric field concentration and by structural analysis of Carrier Pipe for easy installation of High Insulating Rubber Sleeve in the field, which is core technique of connection system. According to the results, the thickness of Carrier Pipe needs at least 9mm by optimization analysis of deformation behavior and insulating design & relaxation of electric field concentration. The result of contraction behavior of the connection part can be demonstrated with the same result of electric field relaxation analysis at the boundary of the electrode inserted into the insulating rubber sleeve.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.532-535
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• 2009

본 논문은 초고압 전력케이블의 접속재 개발을 위한 연구결과로써, 접속시스템의 핵심기술인 고절연 고무슬리브 및 현장에서 접속 작업의 용이성을 위한 Carrier Pipe의 구조해석과 전기적 절연설계에 의한 주요부의 전기적 특성과 전계의 집중을 완화하기 위해 Simulation Tool을 이용한 수치해석 등을 실시하여 최적화된 제품을 제작하였다. 절연설계 및 전계완화 해석에서는 고절연 고무슬리브 구조에서 전계가 집중될 수 있는 중요 포인트를 벡터로 선정하였고 이를 기초로 전계해석을 진행하여 선정된 포인트들에서 전계가 집중됨을 검증하였다. 접속재의 수축거동 해석에 의하면, Carrier Pipe의 구조적 안전성을 확보하기 위하여 고절연 고무슬리브로부터의 압력을 구하여 계산한 결과 최소한 9mm이상의 Carrier Pipe 두께가 필요한 것으로 파악 되었다. 이것은 충분한 강도뿐만 아니라 Carrier Pipe의 변형발생으로 인한 현장에서의 설치문제까지 고려하게 된 값이다. 고절연 고무슬리브 제품설계 에서는 고절연 고무슬리브의 특성조건을 설정하였고 고절연 고무슬리브 제품 및 Carrier Pipe의 Interface 설계 기준을 파악하기 위하여 기존의 고절연 고무슬리브를 활용하여 Carrier Pipe와의 장착 Test를 진행하였다. 그 결과, 확장비율 110%로 적용하였을 경우는 30시간 후에는 완전 붕괴가 되었고, 붕괴가 시작되는 지점이 고절연 고무슬리브의 중앙매립전극 경계면으로써, Simulation Tool을 활용한 접속재 수축 거동 해석 결과와도 일치함을 검증 할 수 있었다.

• Journal of the Korean Society of Safety
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• v.21 no.3 s.75
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• pp.101-106
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• 2006

Formwork is a temporary structure that supports its weight and that of freshly placed concrete as well as construction live loads. In constructions site, pipe supports are usually used as shores which are consisted of the slab formwork. The strength of a pipe support is decreasing as it is frequently being used at the construction site. Among the accidents and failures that occur during concrete construction, there are many formwork failures which usually happen at the time concrete is being placed. The objective of this study is to find out the strength change of used pipe support and unused pipe supports according to aging. In this study, 2857 pipe supports were prepared. Among these pipe supports, 2337 pipe supports were lent to the construction companies free of charge. 520 pipe supports were kept on the outside. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports as well as used pipe supports was decreasing according to age, use frequency and load carrier, and the strength of used pipe supports was lower than the strength of unused pipe supports at the same age. So, the strength of used pipe supports from 191 days to present day was not satisfied the specification of KS F 8001. In this study, the strength of pipe support according to age, use frequency and load carrier was predicted using SPSS 12.0. It was known that the strength of pipe support using for 5 years was reduced to 42.8%. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the present study results will be able to provide a finn base to prevent formwork collapses.

• Journal of the Korea Construction Safety Engineering Association
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• s.38
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• pp.79-87
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• 2006

Formwork is a temporary structure that supports its weight and that of freshly placed concrete as well as construction live loads. In constructions site, pipe supports are usually used as shores which are consisted of the stab formwork. The strength of a pipe support is decreasing as it is frequently being used at the construction site. Among the accidents and failures that occur during concrete construction, there are many formwork failures which usually happen at the time concrete is being placed. The objective of this study is to find out the strength change of used pipe support and unused pipe supports according to aging. In this study, 2857 pipe supports were prepared. Among these pipe supports, 2337 pipe supports were lent to the construction companies free of charge. 520 pipe supports were kept on the outside. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports as well as used pipe supports was decreasing according to age, use frequency and load carrier, and the strength of used pipe supports was lower than the strength of unused pipe supports at the same age. So, the strength of used pipe supports from 191 days to present day was not satisfied the specification of KSF 8001. In this study, the strength of pipe support according to age, use frequency and load carrier was predicted using SPSS 12.0. It was known that the strength of pipe support using for 5 years was reduced to 42.8%. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the present study results will be able to provide a firm base to prevent formwork collapses.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.1
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• pp.98-106
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• 1998

This paper shows the temperature distribution of double hull compartment and of cofferdam in a large LNG Carrier. In LNG Carrier, due to the lower cargo temperature($-163^{\circ}C$), structures are forced to lose their strength if additional heat is not supplied. So it is very important to estimate the temperature distribution and the heat flux needed to maintain the structure properly. The temperature of each compartment is obtained using 2-dimensional model analysis and compared with 3-dimensional results. And also this paper gives preliminary estimation of pipe length to supply necessary heat flux in bare pipe and finned pipe.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.120-125
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• 2005

Formwork is a temporary structure that supports its weight and that of freshly placed concrete as well as construction live loads. Among the accidents and failures that occur during concrete construction, many are formwork failures which usually happen at the time concrete is being placed. In constructions site, pipe supports are usually used as shores which are consisted of the slab formwork. The strength of a pipe support is decreasing as it is frequently being used at the construction site. The objective of this study is to find out the strength change of used pipe support and unused pipe supports according to aging. In this study, 2857 pipe supports were prepared. Among these pipe supports, 2337 pipe supports were lent to the construction companies fire of charge. 520 pipe supports were kept on the outside. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports as well as used pipe supports was decreasing according to age, use frequency and load carrier, and the strength of used pipe supports was lower than the strength of unused pipe supports at the same age. So, the strength of used pipe supports from 191 days to present day was not satisfied the specification of KS F 8001. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the present study results will be able to provide a firm base to prevent formwork collapses.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.789-790
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• 2008

• Korean Journal of Computational Design and Engineering
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• v.12 no.5
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• pp.321-329
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• 2007

The present pipe modeling method requires detailed inputs from a designer to generate a pipe model, and thus it takes much time for the designer to perform such task. Moreover, the pipe model has no relation with the hull structure. Thus, it is time-consuming and requires much effort if design changes arise. In this study, a generating method that generates quickly many pipes using a pipe tray and a conversion method that converts automatically the pipes into objects related with the hull structure are proposed. A pipe modeling system based on the proposed methods is developed. The applicability of the developed system is demonstrated by applying it to the generation of the pipe model of a deadweight 300,000 ton VLCC(Very Large Crude oil Carrier). The results show that the developed system can quickly generate the pipe model in relation with the hull structure.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.69-75
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• 2005

Recently it was reported that the vibration problems on the oil pipe support structure of the crude oil carrier were occurred. in order to investigate the vibration characteristics and the causes of the vibration occasionally. the vibration measurements and impact tests for the oil Pipe structure were carried out. From the measurement results severe vibration was caused by the resonance between the transversal natural frequency of the structure and $6^{th}$ order excitation force of the main engine. Providing the proper countermeasures a series of the vibration analyses were carried out based on the measurement results. From the analysis results, it was concluded that the vibration characteristics of the oil pipe structure were affected by the oil pipes, support structure itself, upper deck structure and the installation spaces and the standard design was established for the crude oil carriers.