• Journal of the Korean Institute of Gas
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• v.14 no.6
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• pp.27-30
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• 2010

This paper presents the system design process of district community cooling system using LNG cold energy. The newly developed LNG cooling system includes several heat exchangers, LNG storage tank, thermal mass storage tank, several cold energy storage tanks, gas air-conditioners, compressors, constant pressure regulators, cold energy and hot energy supply pipes. In addition, the gas air-conditioner system is installed to supply not sufficient cold energy due to low level of city gas consumptions during a summer period. This system design is very effective and safe to supply cold energy mass of fresh air by exchanging two thermal masses of an air and 200kcal/kg cold energy of LNG. The district community cooling system with LNG cold energy does not produce CO2 and freon gases in the air.

• Fire Science and Engineering
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• v.26 no.4
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• pp.70-76
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• 2012

This paper deal with vehicle fire caused by damage of diesel particulate filter (DPF) on diesel passenger vehicles. In order to reduce particulate matters included exhaust gases, a DPF in the exhaust system were installed diesel vehicles. A DPF was broken by excessively trapped particulate matters, regeneration error with a malfunction of ECU and defect of suction system such as swirl valve. If the DPF was broken, hot exhaust gases was released to the bottom of vehicle and released hot exhaust gases lead to occur the fire through combustible materials around the exhaust system. When a fire happened in the diesel vehicle caused by damage of DPF, silicate inorganic compounds were attached to the exhaust ventilation pipe and muffler. The silicate inorganic compounds were created by DPF combustion consisting of raw material ceramics. If the silicate inorganic compounds attached to the tail pipe in the diesel passenger vehicles, its fire cause will be assumed damage of DPF.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.9-18
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• 2011

This study was performed to investigate species diversity of understory in Mt. Biryong. The quadrat size was installed based on the result of analysis of Species-Area Curve. The vascular plants were enlisted 107 taxa: 47 families, 80 genera, 91 species, 11 varieties, 2 subspecies, and 3 forms. The three taxa such as Carex okamotoi, Philadelphus schrenkii var. schrenkii, and Weigela subsessilis were enlisted from the surveyed sites as the Korean endemic plants. Due to the list from the Korea Forestry Administration, Rhododendron micranthum was enlisted as the rare plant. The growth from was categorized followed by forbs, shrubs and trees, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.32-40
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• 2018

In order to avoid excessive vibration, it is required to carry out a vibration analysis of heat-exchanger/nuclear-reactor at the design stage. Information of eigen-frequency in the vibration problem is required to evaluate safety of heat-exchange/nuclear reactor. This paper describes a numerical method, Galerkin's method, to solve the eigenvalue problem occurred in a cantilever beam. The beam is restrained with added mass and spring at the free end or a node point of a mode shape. The numerical results of eigen-frequency were compared with simple analytical and experimental results given by simple approach and simple test, respectively. It is found that Galerkin's method is applicable to estimate the eigen-frequency of the cantilever beam. The frequencies become lower with increasing the added mass and the frequencies increase with the spring force. It is shown the heavy added mass has a role of support on the flexible tube. The eigen-frequency of the first mode, for the system with the added mass mounted at the free end, can be calculated by the approximate analytical method existing with more or less accuracy.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.72-76
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• 2023

Among urban gas-using facilities, more and more cases are using gas meters for leakage inspection instead of inspection ports for concealment pipes. Leak alarm alarms were continuously generated according to the boiler's special usage pattern in an environment where there was no actual gas leakage among some households where this meter was installed. It does not perform its original function of detecting actual gas leakage. Based on these problems, this study analyzed the conditions under which the gas meter for leakage inspection generates leakage alarms according to the boiler's special gas use pattern, and sought a set value that can generate an alarm only in the case of actual gas leakage. Through this, it is intended to relieve citizens' anxiety about gas use due to malfunction of the alarm and at the same time perform the original function of the meter that can detect leaking gas.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.245-245
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• 2010

우리나라 생활폐기물 중 음식물쓰레기는 가장 많은 부분을 차지하고 있다. 또한, 음식물쓰레기에서 발생되는 음폐수의 발생량은 8,926톤/일에 달하고 있지만, 이 중 극히 일부만이 하수처리장 등에서 병합 처리되고 있고 대부분은 해양 투기되고 있는 실정이다. 이에 본 연구에서는 독일 GBU사로부터 중온/습식/이상 혐기성 소화 기술을 도입하여 HADS Pilot Plant를 설치하였고, 2008년 3월부터 국내 음폐수 및 음식물쓰레기에 적합한 최적의 운전기술을 확보하기 위한 Pilot Test를 실시하였다. 본 실험에 사용된 HADS Pilot Plant는 산발효조($6m^3$), 메탄발효조($50m^3$), 안정화조/가스저장조($40m^3$)그리고 가스 소각기로 구성되어 있다. 그리고 적용 음폐수 및 음식물쓰레기는 경기도 Y군에 위치한 사료화 시설에 반입되는 것을 이용하였는데 음폐수는 평균 TS 13.5%, VS 80%, pH $3.7{\pm}0.2$의 성상을 나타내었다. 이를 이용해 계단식으로 유기물 부하를 증가시키면서 $4kgVS/m^3/d$까지 적용하며 중온 상태에서 혐기성 소화를 실시한 결과, $0.8Nm^3/kgVS_{rem}/d$의 바이오가스 회수 및 85%의 VS 감량이 가능함을 확인하였다. 그리고 음식물쓰레기는 음폐수와 달리 1차 파쇄/선별기 및 배관상에 설치되는 2차 미세파쇄/선별기를 통한 전처리를 실시하였고, 1차 파쇄/선별 후 평균적으로 TS가 17.4%, VS는 81%, pH는 $3.85{\pm}0.2$의 성상을 나타내는 음식물쓰레기를 2차 미세파쇄/선별기를 거쳐 Pilot Plant의 산발효조에 투입하여 중온상태에서 혐기성 소화를 실시하였다. 음폐수 적용시와 마찬가지로 계단식으로 유기물 부하를 증량하면서 $4kgVS/m^3/d$까지 적용하여 운전하였고, 그 결과 약 $0.9{\sim}1.2Nm^3/kgVS_{rem}/d$의 바이오가스 회수와 85~87%의 VS 감량 효율을 확인하였다. 음폐수와 음식물쓰레기의 혐기성 소화 실험 결과, 제거된 VS량을 기준으로 보았을 때, 음식물쓰레기에서 더 많은 바이오가스 발생하였는데 이는 음식물쓰레기에 존재하는 고형물이 미생물들의 서식 공간으로 활용됨에 따라 혐기성 소화 과정에서 일어나는 혼합 발효 및 공영양 대사가 음폐수 대비 좀 더 수월하게 일어날 수 있게 된 데에 따른 결과라고 생각된다. 당사의 HADS Pilot Plant test에서는 계단식의 순차적인 유기물 부하 증량과 총VFA/총 알카리도 비율을 0.3~0.4 수준이하로 유지하며 운전함에 따라 음폐수와 음식물 모두에서 안정적으로 $4kgVS/m^3/d$까지의 유기물 부하 적용이 가능하였다. 또한, 생산된 바이오가스 내 메탄의 함량은 60~65%를 유지하였으며, 메탄발효조의 pH는 별도의 조절이 없이도 운전기간 동안 평균 7.8~7.9 수준을 유지하였다. 이처럼 pH 3.7~3.8의 음폐수 또는 음식물쓰레기의 투입에도 안정적인 완충능력을 보여준 것은 소화조 내에서 기질로부터 분해되어져 나오는 암모니아와 이산화탄소가 강력한 버퍼 시스템을 구축하고 있음에 따른 결과로 사료된다. 그리고 음폐수와 음식물쓰레기의 경우 모두 85%이상의 높은 VS 제거율을 보여주었는데 이는 당사의 HADS Pilot Plant 소화조의 구조가 내통과 외통으로 구분되어져 있음에 따라 plug flow + CSTR의 특징을 가짐에 따른 결과로 판단된다. 상기한 결과를 바탕으로 향후에는 $5kgVS/m^3/d$ 수준의 유기물 부하 적용운전도 계획하고 있다.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.84-90
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• 2018

We researched the way to minimize the damage when the chlorine-leak accident take place in a purification plant. Since the level of risk based on the Off-site Risk Assessment(ORA) is a combination of proportional to the number of residents in the damaged area and frequency of accidents, we suggested the adequate conditions to reduce the number of residents in the damaged area by means of the operating temperature of a handling facility, installation of a emergency shut-off valve, and the analysis of the variation of the damaging range in accordance with the type of enclosure. The coverage of damage was calculated by the 'KORA(Korea Off-site Risk Assessment Supporting Tool) program. The research shows that the lower operating temperature gets, the more emergency shut-off valve being installed and the higher enclosure level of facility becomes, the extent of damage gets decreased. The decreasing rate of worst case was 17.6%, 71%, 34.5% respectively, the decreasing rate of alternative case was 31.6%, 69.0%, 34.8% respectively.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.6 no.3
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• pp.15-24
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• 2007

According to an apartment house environment and the service provide method of major telecom operators, is providing optic-LAN service with installing the equipments of optical office center and optic distribution at MDF(Main Distribution Frame) and under-ground of apartment. therefore the distribute is deepening between service providers because of space securement to install equipments and spare pipe securement to reinstall UTP cable. These were reasons that operators leaned to subscriber collection and neglected to maintenance, in addition, insist the facilities invested by each operators is his own assets for all that in-plant of apartment house is private land. So, would not being touched by others. Accordingly, this study will search it through the field current condition examine that service's types and methods which various telecom operators and broadcast operators are providing, the current conditions of being maintained, the problems of being happened. etc. and would like to improve that the users could use the services safely by making the information & communication facilities maintenance mandatory under the regular size of apartment house circumstances through the analysis of various laws relations which are managed information & communication construction work law, telecommunication basis law, home network. etc. technical standards by the Ministry of Information and Communication and are managed housing law, construction law, the regulation related to house construct standards. etc. by the Ministry of Construction and Transportation.

• Journal of the Society of Disaster Information
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• v.14 no.2
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• pp.107-114
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• 2018

Purpose : This study is to develop walls using wall recording technology applied on roofs to prevent fire spread in traditional markets. Method : The spray head installed on the developed wall was designed so that the fire does not spread to adjacent buildings after being used for plants. In addition, a spray head was attached to the upper section and some sections for the growth of plants planted on the wall to prevent the spread of fire. Results : These technologies suggested the development of walls that can be installed at the upper level of buildings, such as traditional markets, and separate isolation facilities were not necessary because they are integrated with structures and sprinklers. In addition, sprinklers can perform both the plant spray and fire spread prevention functions. It is believed that this is the only alternative technology proposed in Korea to prevent the spread of fire. Conclusion : In this study, the wall design, designed directly to derive the quantitative performance of the fire spread reduction effect, demonstrated the fire suppression method of the wall system, the durability of the wall itself, and the flame retardability performance.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.62-69
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• 2001

Gas safety devices are very effective to prevent catastrophic gas accident in domestic. The safety devices are included in domestic gas equipment such as extinguishing safety device and adapted at pipeline such as fuse cock, shut off device with gas alarm and so forth. In spite of using those safety devices, a few hundreds of gas accident was happened annually in residential house. In this study, we analysed systematically the domestic accidents which was happened in five years using fault tree analysis(FTA) method and analysed the effectiveness of individual safety device. And also, it was suggested that the rate of accident was decreased quantitatively by increasing safety device which is adapted in domestic. By analysis of 769 gas accidents in domestic, the order of effectiveness of safety device to prevent domestic gas accident was the multi-functional gas-safe-meter(micom-meter), fuse cock, gas leak alarm and CO alarm. If the above four kind of safety device are adapted to every house, about $59\%$ of accident will be reduced and the most of catastrophic gas accident will be Prevented in domestic.