• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.161-169
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• 2015

A fire sprinkler system is very important to extinguish fire in the building. The sprinkler system initiates sprinkler discharge if the detection system identifies a developing fire and opens the pre-action valve. However, pre-action fire sprinkler systems mainly installed in the underground parking lot at the apartment complex do not properly operate at fire if the connection type of fire sprinkler systems does not properly installed and operated. This study identified the relationship between fire dispersion & damage and the connection type of water supply in the sprinkler system from many fire cases at the apartment complex in South Korea. In addition, this study also identified the water supply differences and characteristics between South Korea and foreign countries. The main purpose of this study is also to improve the water connection types in the sprinkler system that can reduce the potential failures of pre-action valve operation through electrical signal system. The study also suggests the improvement plan for water connection types in pre-action fire sprinkler system that can minimize potential failure of pre-action fire sprinkler system. The suggestions for revising the fire safe standard in South Korea includes letting the water supply pipe of sprinkler system water inlet connect to the second side of pre-action valve and the water flow device that can minimize potential failure of sprinkler system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.7
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• pp.610-616
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• 2008

For this study, the forming analyses and body strength tests of TBP were performed on the main pipe size 150A(KS D3507, KS D 3576 10S). The branched pipe sizes utilized were 25A, 32A, 40A, 50A, 65A, 80A, 100A and 125A. A general FEM program, ABAQUS, was used as the forming analyses method of TBP. Using the results, the strength of TBP was then tested in order to determine the safety of TBP when the working pressure was applied. The results indicate that TBP may be safely used in water-based fire protection pipe systems in terms of the strength.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.219-219
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• 2000

A Plate type pipe is used for heat exchange in radiator of a vehicle. The pipe has several rooms through which water flows and heat is dissipated into outside . In the case that there are small holes, cracks or some scratches on the plate, the radiators lost their functions due to Leakage. This may result in overheating of engine in a car. Thus, we need to perform the entire inspection of the plate type pipe in advance before assembling the radiator. In manufacturing process of the plate type pipe, the productive speed is very high and that may be performed continuously. So, there is no room to perform the outlook inspection by typical image processing techniques. This paper proposes a new method to inspect the outlook surface of the plate type pipe automatically with high speed. Especially, the sequential processing technique of an algorithm which detects defects on the surfaces of the plate type pipe is proposed for line scan camera which captures line image. To evaluate the inspection performance, a series of experiments is performed.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.2
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• pp.197-206
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• 2016

Although the Hazen-Williams C factors are very important in the design, operation, and maintenance of water supply pipes, sufficient studies for them have been not reported in korea, which are based on experiments or measured data. Because of this, we have estimated C factors by measurement considering constraints in time precise safety diagnosis for multi-regional water supply system were performed. In this study, we confirmed constraints and variables characteristics of Hazen-Williams equation, and collected reliable C factors data of 174 by measurement, and analyzed their characteristics. According to collected data, the average value is 115.35, which is almost equal to the value of design standard or a little higher than it in korea. Also, among the equations suggested to determine C factor in the past, the C factors calculated by Sharp and Walski equation was closest to them in this study. In addition, to analyze collected C factors, use year and pipe diameter having high correlation with them were respectively divided into there categories. Analysis results showed that C factors evidently decreases depending on increases in use year, on the other hand, size of pipe diameter is proportional to value of them. In conclusion, this research showing evaluation and characteristics for C factors based on measured data will be used as practical reference in determining C factor in multi-regional water supply systems at a later date.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.170-179
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• 2017

We investigated design requirements of feed water drain and hydrogen vent systems for the sodium-water reaction pressure relief system (SWRPRS) of the prototype generation IV sodium cooled fast reactor (PGSFR). We evaluated the areas of the gas vent pipe of the water dump tank and the length of the water drain pipe of the steam generator to rapid drain of the water steam inside the steam generator for the normal and refueling operations, respectively. We also calculated the diameter of the gas vent pipe of the sodium dump tank which met its design pressure.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.5
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• pp.15-21
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• 2008

The purpose of this study is to estimate deterioration assessment for weighting factors in pipe network for which each local selfgovernment takes rehabilitation and replacement work at present time. Deterioic hierarchy process(AHP), calculates the weighting factors. The appropriate marks matrix of sixteen deterioration factors are made for the precise decision standard of pipe condition through the result of this analysis. The marks matrix of sixteen deterioration factors can solve the complicated decision making problems of pipe rehabilitation workration factors in the pipe network might be influenced by local factors, such as province, location, or land use, in water supply systems. In this study, the sixteen deterioration factors are determined suitable for domestic situation based on the pipe deterioration factor data inside and outside of the country. Also, we select persons in charge of calculating the detail weighting factors and do survey about important level of each deterioration factors. Delphi method, a question survey method applying the analyts.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.2
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• pp.103-116
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• 2005

Although there have been many researches to construct a database of water distribution networks using GIS, most of them were not linked with an model for the analysis of pipe networks because it is difficult to make spatial data about complex water distribution networks for building a detail model. Therefore, it is necessary to develop the method based on GIS to build geographical data for design of water distribution pipeline systems. In this study, an innovated design support technique using GIS is proposed for a hydraulic analysis model of water distribution networks. With the function of spatial analysis in GIS system, the results from a pipe network model are used to analyze the suitability of the location of pipeline network, the spatial suitability comprised the analysis of the degree of pipe age, the altitude distribution of water pressure, and the water supply system for the customer.

• Journal of Korea Water Resources Association
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• v.31 no.4
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• pp.439-448
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• 1998

There are many methods to calculate steady-state flowrate in a large water distribution system. Linear method which analyzes continuity equations and energy equations simultaneously is most widely used. Though it is theoretically simple, when it is applied to a practical water distribution system, it produces a very sparse coefficient matrix and most of its diagonal elements are to be zero. This sparsity characteristic of coefficient matrix makes it difficult to analyze pipe flow using the linear method. In this study, a graph theory is introduced to water distribution system analysis in order to prevent from producing ill-conditioned coefficient matrix and the technique is developed to produce positive-definite matrix. To test applicability of developed method, this method is applied to 22 pipes and 142 pipes system located nearby Taegu city. The results obtained from these applications show that the method can calculate flowrate effectively without failure in converage. Thus it is expected that the method can analyze steady state flowrate and pressure in pipe network systems efficiently. Keywords : pipe flow analysis, graph theory, linear method.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.64-71
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• 2012

An efficient cooling system is an essential part of the electronic packaging such as a high-luminance LED lighting. A special technology, Pulsating Heat Pipe (PHP), can be applied to improve cooling of a sealed, explosion-proof LED light fixture. In this paper, the characteristics of the pulsating heat pipes in the imposed thermal boundary conditions of LED lightings were experimentally investigated and a PHP device that works free of alignment angle was investigated for cooling of explosion-proof LED lights. Five working fluids of ethanol, FC-72, R-123, water, and acetone were chosen for comparison. The experimental pulsating heat pipe was made of copper tubes of internal diameter of 2.1 mm, 26 turns. A variable heat source of electric heater and an array of cooling fins were attached to the pulsating heat pipe. For the alignment of the heating part at bottom, an optimum charging ratio (liquid fluid volume to total volume) was about 50% for most of the fluids and water showed the highest heat transfer performance. For the alignment of the heating part on top, however, only R-123 worked in an un-looped construction. This unique advantage of R-123 is attributed to its high vapor pressure gradient. Applying these findings, a cooling device for an explosion-proof type of LED light rated 30 W was constructed and tested successfully.

• Corrosion Science and Technology
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• v.12 no.4
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• pp.179-184
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• 2013

Pipe wall thinning caused by erosion and corrosion can adversely affect the operation of aged nuclear power plants. Some injured workers owing to pipe rupture has been reported and power reduction caused by unexpected pipe damage has been occurred consistently. Therefore, it is important to develop erosion-corrosion damage prediction model and investigate its mechanisms. Especially, liquid droplet impingement erosion(LDIE) is regarded as the main issue of pipe wall thinning management. To investigate LDIE mechanism with corrosion environment, we developed erosion-corrosion damage simulation apparatus and its capability has been verified through the preliminary damage experiment of 6061-Al alloy. The apparatus design has been based on ASTM standard test method, G73-10, that use high-speed rotator and enable to simulate water hammering and droplet impingement. The preliminary test results showed mass loss of 3.2% in conditions of peripheral speed of 110m/s, droplet size of 1mm-diameter, and accumulated time of 3 hours. In this study, the apparatus design revealed feasibility of LDIE damage simulation and provided possibility of accelerated erosion-corrosion damage test by controlling water chemistry.