• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.101-105
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• 1997

When the water curtain system is employed to keep the liquefied gas in the underground storage cavern, clogging is observed in borehole. Since this phenomenon causes serious difficulties in managing LPG storage cavern, it needs to detect the degree of clogging accurately under various circumstances. Thus, in this study the active factors of clogging, that is, groundwater head, injection water flowrate, and seepage water flowrate, were investigated experimentally using a physical model. Experimental results show that groundwater head around storage cavern increases as cavern Pressure increases, while it decreases as clogging becomes severe. The pressure in storage cavern is required to reduce up to atmospheric pressure in order to detect and identify the degree of clogging more accurately. The decrease of uroundwater head due to clogging slows down as the pressure in borehole increases. As amounts of suspended matters in injected water increase, both injection water flowrate and seepage water flowrate decrease linearly with time, and the flowrate of injection water drops rapidly compared with seepage water flowrate.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.298-301
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• 2011

본 연구에서는 지하 방호공간에서 화재가 발생한 경우 워터커튼 시스템에 의한 연기의 차단효과와 화재제어 특성을 분석하였다. 이를 위해서 분사각도 $180^{\circ}$, 오리피스 직경 8.2 mm의 노즐과 지하방호 공간용 실화재 실험 장치를 제작하였으며, 화재강도 1.5 MW 기준 A급 1단위 화재 실험으로부터 온도분포와 가시도를 측정하여 연기의 차단효과를 확인하였다. 화재제어 특성을 분석하기 위해서 NIST(National Institute of Standards and Technology)의 해석프로그램인 FDS(Fire Dynamic Simulator)를 사용하여 동일한 실험조건에서 온도분포를 비교하였으며 노즐의 설치개수 변화에 대한 화재해석 및 실험결과로부터 워터커튼 시스템은 노즐의 설치위치와 개수, 화원으로부터의 거리, 제연 등의 설비 조건과 분사 노즐의 특성, 공급 유량 등이 중요한 상관관계를 갖고 있음을 확인하였다.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2003.10a
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• pp.187-191
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• 2003

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.202-213
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• 2003

Tower Palace III project is the highest residential and commercial high-rise complex building in Korea. In order to construct a high-rise building, advanced construction and engineering technology is required. Therefore, with more developed construction and engineering technology based upon accumulated knowledge, construction speed of 13.4 days per floor including finish work was achieved in this project. To achieve this project successfully, three main advanced construction technology were applied: 1) Construction methods for 3-day cycle of structural work and curtain wall, 2) Tact scheduling method for finish work, 3) Management system of material, labor, work, and information. Also, four main engineering technology were applied: 1) New material such as high -flowing concrete and high strength concrete of 800 kgf/cm2, 2) New method such as a pipe-cooling system of a cool water circulating type, 3) Mechanical system such as smart-fan controlling kitchen-ventilation system, 4) Electrical system such as false car system.

• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.251-258
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• 2014

In order to set up the basic environmental control systems which the new concept greenhouses have to equip, greenhouse characteristics, environmental management and control systems in domestic glasshouses and plastic houses were investigated and analyzed comparatively. Survey results on the width, length, eaves height, and the number of spans etc. showed that glasshouses were bigger than plastic houses significantly. New concept greenhouses claim to be plastic houses, but it will be reasonable to follow the specifications of the glasshouse. Specifications to be applied to new concept greenhouses were proposed as follows; hot water heating systems, aluminum screens as the thermal curtain, evaporative cooling systems, roof vents on the ridge, circulation fans, $CO_2$ enrichment, hydroponic systems, and automatic irrigation control systems. Environmental measurement systems for the indoor and outdoor temperature, humidity, light, wind speed and indoor $CO_2$ concentration have to be fully equipped. The automatic control system has to be as a complex environmental control system, not a single item control system. Also, for stable dissemination, domestically producing complete greenhouse control system should be made as soon as possible.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.869-887
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• 2008

Coffer dam for tunnel type spillway in inflow section of Dae-am dam was originally planned as 2 lines sheet piles with Water Zet method. But, the result of pilot test was caused of some problems that vibration during installation of pile could pollute water and water leakage could the lower part. So, sheet piles was not satisfactory for faculty of coffer dam. Structural instability of sheet pile system need to reinforcement. Characteristic of Dae-am dam was small reservoir capacity but wide drainage area, of which it was judgment that security of leakage and stability was difficult during excavation of inlet part. So, we consider that water curtain method utilized with in site pouring concrete pile method was designed at weir part of spillway. We were known about basement rock that geological boring was carried out in weir part. After taking a deep consideration, PRD method was accepted as a new method. Concrete pile by PRD was installed to below country rock. CJM method was carried out with PRD. After making concrete wall using Top-down method, earth anchors were installed for supporting it. According to the result of numerical analysis, as water level rises, wall is stable.

• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.3
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• pp.35-42
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• 2011

The exterior system of buildings, which is the typical curtain wall, has been made with glass and metal. Theses materials, however, have weaknesses such as inadequate insulating quality, short durability, combustibility and toxic substance. On the other hand, Autoclaved Aerated Concrete(AAC) or Autoclaved Lightweight Concrete(ALC) possess the great energy efficiency and the superb insulating quality as substitute of existing exterior system materials. In this research, strength characteristics and bubble dispersion of hydrothermal synthesis process of AAC based on CaO/$SiO_2$(C/S) ratio are analyzed. C/S ratio is determinated and bubble distribution and compressive strength are studied through the test of varied water-to-solid mineral ratio(W/S). In hydrothermal synthesis program, final C/S ratio is determined as 0.7 consider of the manufacturing process and hydrothermal synthesis is done at $180^{\circ}C$ for 7 hours. The analysis shows slurry has about 2,300cP viscosity and 0.56 specific gravity therefore it is expected AAC has the appropriate facility in the manufacturing process and Hydrates of AAC's Expansion.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.1-12
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• 2010

The objective of this study was to examine the hydrogeochemical and microbiological characteristics for stable maintenance of coastal LPG storage cavern. Cavern seepage water and groundwater in the vicinity of the LPG storage cavern were sampled and analyzed (February, May, August and October 2007). Groundwater samples of propane cavern showed high pHs of 8.1~12.4 due to dissolution of cement grouting materials that had been applied during the well and cavern construction. The EC values showed distinctive seasonal variation. The negative ORP indicated reduced condition. The seepage and surrounding groundwater are classified as Na-Cl type, which represents seawater effects. All of aerobic bacteria, anaerobic bacteria, slime forming bacteria and sulfate reducing bacteria were less than 500 CFU/mL, which indicated that there was no abrupt increase of bacteria in the cavern. Therefore there exist no hydrochemical symptoms to indicate unstable conditions of the cavern operation. However, regular and continuous monitoring is essentially required.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.355-360
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• 2013

Diesel-burning air heater (air heater) and infrared heating lamp (infrared heater) were installed as auxiliary heaters in two single water-curtained plastic greenhouses with a set night temperature of $6^{\circ}C$ for cultivation of strawberry 'Seolhyang'. The average night air temperature was $6.6^{\circ}C$ in the infrared heater treatment and $7.1^{\circ}C$ in the air heater treatment. However, when the minimum outside temperature fell below $-10^{\circ}C$, the air heater had less internal temperature fluctuations. In contrast, the infrared heater had some cases of falling below the set temperature. The relative humidity was higher than 98% by the side-effect of water-curtain system regardless of the heating system. There was about $5^{\circ}C$ difference in leaf temperature between the turned-on and -off state of the infrared heater, and the efficacy of the infrared heater on leaf temperature was only limited to about 4 meters from the system. Peduncle length and plant height in the infrared heater tended to be greater than those in the air heater. There was, however, no statistically difference in leaf size and numbers of leaves, flowers on first cluster and branches. There was no difference in soluble solids content, fruit firmness, average fruit weight of the harvested fruits, and the yield. Comparing the heating costs, the air heater system took 622,662 won based on 543 L tax-free diesel, while the infrared heater system took 235,284 won by consuming 5,685 kWh of electricity, and 62.2% heating costs saving was achieved.

• Journal of the Korea Computer Graphics Society
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• v.25 no.3
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• pp.143-152
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• 2019

This paper presents two new techniques for solving the two problems of the water curtain: 'shape distortion' caused by gravity and 'resolution degradation' caused by fine satellite droplets around the shape. In the first method, when the user converts a three-dimensional model to a vertical sequence of slices, the slices are evenly spaced. The method is to adjust the time points at which the equi-distance slices are created by the nozzle array. In this method, even if the velocity of a water drop increases with time by gravity, the water drop slices maintain the equal interval at the moment of forming the whole shape, thereby preventing distortion. The second method is called the minimum time interval technique. The minimum time interval is the time between the open command of a nozzle and the next open command of the nozzle, so that consecutive water drops are clearly created without satellite drops. When the user converts a three-dimensional model to a sequence of slices, the slices are defined as close as possible, not evenly spaced, considering the minimum time interval of consecutive drops. The slices are arranged in short intervals in the top area of the shape, and the slices are arranged in long intervals in the bottom area of the shape. The minimum time interval is pre-determined by an experiment, and consists of the time from the open command of the nozzle to the time at which the nozzle is fully open, and the time in which the fully open state is maintained, and the time from the close command to the time at which the nozzle is fully closed. The second method produces water drop sculptures with higher resolution than does the first method.