• Journal of the Korean Institute of Gas
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• v.16 no.2
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• pp.1-8
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• 2012

According to the last 5 year statistics of KGS, there occurred 22 under ground gas pipe accidents per year in Korea. And about 5 accidents per year were caused from the third party digging. IT recognition technique could reduce such underground gas accidents. Among IT recognition technique, RFID is most poplar. In the air, RFID were applied to various fields including the distribution industry, but underground condition, the research and application cases of RFID were little This research was undertaken to see the applicability of RFID to underground gas pipe safety. By use of 900 MHz RFID reader and commercial metal tag, the stable recognition distance was measured in the similar underground condition of LNG pipe. Stable recognition depth of RFID tag were measured to be 50, 45, 25 cm in the medium of soil, 5 cm-thick-concrete+soil, and water respectively. The measured distances were considered to be the meaningful distance to prevent the gas pipe accidents Also the efficient ways to input the required gas pipe data to the 24 byte metal tag were proposed. Application of RFID to underground LNG supply system will not only reduce the gas accidents due to third party digging but also improve the gas line maintenance efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.389-391
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• 2022

Efforts by the Ministry of Environment and local governments in Korea are continuing to manage the aging of water supply and sewage buried underground. With the support of the Korea Institute of Environmental Industry and Technology's water and sewage innovation technology development project, it is conducting a project to predict and exchange accidents due to aging, and to apply smart functions to new buried pipes. As one of these studies, this paper proposes the design of a dashboard concept model for digital twin-based smart pipe health monitoring, one of the key features of the entire study. Since remote control and monitoring are one of the main functions, distributed transmission and reception agents are deployed to visualize monitoring situations in real time and to increase user affinity by deploying intuitive UI. To validate the design of this proposed special digital twin based smart pipe state monitoring, we construct the conceptual model level and measure the agent effectiveness to validate its excellence.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.126-129
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• 2008

Using a surplus head in presented water supply pipes, we have studied to improve the operating efficiency of small hydro generator, which was chosen for a test model with Sung-Nam and Bo-Ryong small hydro power plant. With regard to power control and countermeasure of water hammer impact, Finally we have represented the optimal control method through the synthetical analysis of existing system symptoms, operation efficiency, the effect of water hammer impact and system configuration.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.33-40
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• 2010

Individual sewage treatment system is classified into a sewage treatment system which treats all the domestic sewage and a water-purifier tank which treats only effluent flushing from the toilet. The number of registered manufacturers has increased rapidly since 2001. As a result, price competition has increased among the manufacturers and has caused the problems such as the inappropriate production of individual sewage treatment system, the unreasonable permit for building completion and the shortage of the professional technology of the community's public officials in charge. This study collected the problem cases that are related with existing individual sewage treatment system and operation. Efficient improvement plan for the stable supply, installation, maintenance of individual sewage treatment system were suggested.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.111-118
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• 2020

This study developed a rainwater harvesting system for the irrigation of upland on sloping area. The assessment of water supply capacity was evaluated in farm field experience. This system consists of a water catchment device and a collapsible storage tank. The water catchment device was designed to collect runoff water in natural channel of 500 mm width into a pipe of 50 mm inner diameter. The device has funnel-shaped plan and cross-section of square. The storage capacity of the collapsible water tank was caculated to meet the water demand for irrigation in 30 a cultivated land for 10-year frequancy drought. The tank has a cuboid shape with a capacity of 30 ㎥, 5 m in width and length, 1.2 m in height. This system can supply 92% of the water required for drop irrigation of red pepper and 88% of the water required for drop irrigation of onions in 30 a cultivation land during the month of May and June. In the case of 16-dry days of 10-years frequency, this system is capable to irrigate 100% of required water for red pepper and onion, 76.7% of required water for Omija (Schisandra chinensis), and 51.5% of required water for autumn kimchi cabbage.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.421-428
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• 2007

Many engineering problems on the pipeline flow use continuity, energy, friction loss head equation. To calculate friction loss head in a pipeline, Darcy-Weisbach and many average velocity equations can be used and Hazen-Williams equation is used frequently in the pipe network for the water supply systems. Darcy-Weisbach equation is a general one acquired from applying Bernoulli's equation in the pipeline flow and Hazen-Williams equation is a experimental one in case that pipe velocity is below 3m/sec and pipe diameter is over 50mm. In this study, comparing Darcy-Weisbach with Hazen-Williams equation, relation f and C that are expressed as roughness coefficients of those equations is explained. Next, head losses calculated from using those equations are compared and those are applied in realistic pipelines. Comparing f with C, the f is decreasing linearly according to increase of the Reynolds number Re and increasing in case the C is decreasing. additionally, the C is increasing up to a point and then is decreasing according to increase of the Re. Next, the C is increasing and Re's range for increase of the C lengthens in case of decreasing of the relative roughness ${\varepsilon}/d$. Comparing head losses acquired from the two equations, head loss appears large in case that the C is decreasing and the ${\varepsilon}/d$ is increasing. additionally, Head loss calculated by the Darcy-Weisbach equation varies larger than one by Hazen-Williams equation in regard of the Re. Next, change aspect of head loss acquired by the C is distinguished more clearly than the one by the ${\varepsilon}/d$.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.369-382
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• 2017

Accurate and optimal water supply to cereal crop is critical in growing stalks and producing maximum yields. Recently, upland crops are cultivated in paddy field soils to reduce overproduced rice in Korea. In order to increase productivity of cereal crops in paddy fields which have poor percolation and drainage properties, it is necessary to fully understand crop response to excessive soil water condition and management of soil drainage system in paddy field. The objectives of this study were to investigate effects of excessive soil water to sesame growth and to quantify stress response using groundwater levels. Two cultivars of sesame were selected to investigate; Gunbak and Areum. These sesames were planted in paddy fields located in Miryang, Gyeongnam with different soil drainage levels and drainage systems. The experiment site was divided into two plots by drainage class; very poorly and somewhat poorly drained. Two different drainage systems were applied to alleviate excessive soil water in each plot: open ditch and pipe drainage system. Soil water contents and groundwater levels were measured every hour during growing season. Pipe drainage system was significantly effective to alleviate wet injury for sesame in paddy fields. Pipe drainage system decreased average soil moisture content and groundwater level during sesame cultivation. This resulted in greater yield and lignan contetns in sesame seeds than ones from open ditch system. Comparison between two cultivars, Gunbak had greater decrease in growth and yield by excessive soil water and high groundwater level than Areum. Seed components (lignan) showed decrease in seeds as soil water increased. When soil moisture content was greater than 40%, lignan content tended to decrease than ones from less soil moisture content. Based on these results, pipe drainage system would be more effective to reduce wet injury to sesame and increase lignan component in paddy field cultivation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.6
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• pp.568-576
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• 2010

It is widely known that the leak locating of underground plastic pipelines is much more difficult than that of cast iron pipelines. The precision of the leak locating depends upon the speed of leak signal and the time delay estimation between the two sensors on the pipeline. In this paper, six different windowing filters are considered to improve the time delay estimation especially for the plastic pipelines. The time delay is usually estimated from the peak time of cross-correlation functions. The filtering windows including rectangle, Roth, Wiener, SCOT, PHAT and maximum likelihood are applied to derive the generalized cross-correlation function and compared each other. Experimental results for the actual plastic underground water supply pipeline show that the introduction of the filtering windows improved the precision of time delay estimation. Some window functions provide excellent leak locating capability for the plastic pipe of 98 m long, which is less than 1 % of the pipe lengths. Also a new probabilistic approach that the combinations of all results from each filtering window is suggested for the better leak locating.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.11
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• pp.23-29
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• 2010

The principal factor determining an optimum design method for cathodic protection is finding the protection current for preventing the corrosion of existing, already laid pipe. Some factors currently used to test designs include the sizes and lengths of pipes, soil resistivity, and the coating damage rate. We believe this method and current formulae are not optimum due to the uncertainty of determining the coating damage rate and the corrosion protection current's density. This paper analyzes the amount of protection current obtained by performing a temporary current test using data describing existing laid pipe. We then propose determining the corrosion protection current by using the temporary current test after modifying the formula. In addition, we suggest a way to choose optimized cathodic protection and the process of design by executing the design and taking account of such factors as a site condition of 34km-long non-protected water supply pipe lines (stages I and II) in ${\bigcirc}{\bigcirc}$ region, climate, interferences, and durability.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.1
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• pp.50-60
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• 1998

As a method to develop an enhanced heat transfer fluid, the fine particles of a phase-change material were mixed with a conventional heat transfer fluid. Paraffin, which can be obtained easily in domestic market, was used for the phase-change material and water was used as a carrier fluid. Fine liquid particles of paraffin were formed in water as an emulsion by using an emulsifier, and they were cooled rapidly to become solid particle, resulting in paraffin slurry. The average diameter of produced solid particles was inversely proportional to the amount of the added emulsifier, which was theoretically proved. The produced paraffin slurry was tested thermally in heat transfer test section having a constant-heat-flux boundary condition. The test section was made of a circular stainless-steel pipe, which was directly heated by the power supply having a maximum of 50 Volts-500 Amperes. DSC(Differential scanning calorimeter) tests showed that two kinds of phase change were involved in the melting of paraffin, and it was explained in two different ways. A five- region-melting model was developed by extending the conventional three-region-melting model, and was used to obtain the local bulk mean temperatures of paraffin slurry in the heating test section. The local heat transfer coefficient showed a maximum where the bulk mean temperature of the paraffin slurry reached at the melting temperature of paraffin.