• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.3
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• pp.367-373
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• 2003

The present study investigates the fire suppression characteristics using a water mist fire suppression system. The fire extinguishing times are measured for various fire sources, fuel types, and different total flooding rates of water mist. Pool fire with hydrocabon fuel is successfully extinguished within a minute under the operating conditions of the water mist system. Two different regimes of the smoke layer cooling are observed, such as rapid and slow cooling processes. The regimes are divided by threshold time which is calculated with auto-correlation function. The threshold time for the initial cooling decreases with increasing water flow-rates and fire sources. These initial cooling effects play an important role in preventing the occurance of flashover fire by the initial fire suppression.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.28-39
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• 2001

The eco-hydrodynamic model was used to simulation water quality of Kwangyang Bay according to the environmental variation for appropriate water quality management. The mean concentration of COD was 3.3㎎/L, this exceeded the third class of water quality criteria. Waste water discharging loads showed approximately 90% of total pollutant loads. For satisfaction to below 10㎍/L of Chl. a and 2㎎/L of COD, above 35% reduction of present pollutant loads of point sources are needed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.43-50
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• 2005

This study is for the isolated water-Proofing method using Poly-ethylene sheet in the underground water tank which is not affected by construction environments such as wet, low temperature and surface condition. The special features of this water-proofing method are that the construction and management control are very easier and more effective than the existing construction method.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.2
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• pp.51-61
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• 2001

A numerical study has been conducted to characterize the transient pressure in a simple water supply pipe system with an air chamber by utilizing a commercial code that employs the method of characteristics. Some results produced for validation in the study agree quite well with the previously reported. Several parameters are than varied. Among them are the valve closure time, the wave speed, the static pressure, the polytropic exponent, the air chamber volume, the diameter and the shape of orifice in the air chamber, etc, while the water temperature and velocity are kept constant at $20^\circ{C}$ and 0.8m/s, respectively. Results reported in this parametric study may be useful to understand the unsteady behavior of the system.

• Membrane Journal
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• v.6 no.4
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• pp.189-195
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• 1996

It is concluded from this study that human consumption of very low TDS water does not leach minerals from the body that cause ill health effects because; -The human body's own control mechanism of homeostasis and internal body secretions keep tight controls on body fluid composition regardless of drinking water TDS for a normal person under normal csonditions. -The unofficial WHO document's proposed guideline of a 100m/l lower limit for drinking water due to mineral leaching and subsequent ill health was not found to be scientifically or physiologically credible. Leaching of minerals from the body is not officially recognized by WHO. -The experience of the U.S. Navy, Army, NASA and dommunity demonstrations do not support ill health symptoms caused by consumption of low TDS drinking water. -Millions of people regularly consume maturally occurring low TDS water without symptoms of ill health.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.6 no.1
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• pp.1-7
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• 2010

In this paper, an experimental study on the cooling operation characteristics for different entering water temperatures in geothermal heat pump system are carried out by using Lab VIEW system program Set-point temperature controls for cooling water and supply air temperatures is applied to analyze the energy consumption and control performances. As a result, the system responses show that different entering water temperatures(EWT) effect greatly on the energy consumption and system COP.

• Geomechanics and Engineering
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• v.20 no.3
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• pp.267-273
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• 2020

Solutions of the water pressure and groundwater inflow distribution along the tunnel perimeter in a half-infinite aquifer were investigated considering the conditions of the constant head and constant water pressure. It is assumed that the circular tunnel is buried in a fully saturated, homogeneous, isotropic and half-infinite space. Coordinate transformation technique was adopted, the problem of solving the control equations of water pressure in the Cartesian coordinate was transformed to that in the bipolar coordinate system, which can significantly simplify the derivation procedure of the water pressure and inflow distribution. The validation results show the accuracy and advantage of the proposed approach.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.1
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• pp.10-20
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• 2002

A dynamic model of a water heater system heated by a heat pump was developed. The water heater system was composed of heat pump and hot water reservoirs. Finite volume method (FVM) was applied to describe the heat exchangers. A new constraint on electronic expansion valve (EEV) or thermostatic expansion valve (TXV) that can control superheat after the evaporator was developed. Dynamic performances were evaluated for various sizes of the reservoir. In order to compare those performances, time scale was normalized by time constant representing the characteristics of reservoir size. Time constant was determined from quasi steady-state simulation of the system. From the simulation, the size of the water heater reservoir was found to have a large influence on the transient performance of the sys- tem. Therefore, the optimization of the reservoir size is needed in a design process.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1073-1074
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• 2007

The Analysis on stopping trouble for Excitation System The excitation system must be stopped stably on generator's stopping. Therefore through studying on Excitation Stopping scheme, and problems which might happen when stopping, we would like to enhance the stability of generator and control system.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.287-290
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• 2002

Real-time flood submerged area map provides important scientific basis for the decision-making of flood control and relieving disaster. Taking the Wuhan area as an example, this article gives out a image interpretation method under influence of flood, and describes real-time or quasi-real-time flood submerged area map by using the integration of ERS-2 SAR image and LANDSAT TM image in support of remote sensing images process software ERDAS.