• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.638-646
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• 1985

Water hammering in nuclear or thermal power plant condenser cooling water systems in mathematically modeled and numerically analyzed based on the method of characteristics. Effects of variations of the discharge valve operating condition and the system geometry on the hydraulic transients are investigated for the cases when all or one of four pumps are tripped accidently due to loss of offisite power. Effects of ocean waves and tides on the steady-state and the transient operations are also studied. Water column separation in taken into account whenever necessary by means of a simplified physical model.

• Textile Coloration and Finishing
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• v.13 no.2
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• pp.128-134
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• 2001

Following the prior studs regarding that 1.0g of cotton fabric round be dyed uniformly with a reactive dye in the solvent mixture of $2m\ell$ of water and $23m\ell$ of dichloromethane, silk fabric was dyed with C. I. Reactive Blue 203 in the water/dichloromethane two-phase immiscible solvent media. In order to minimize dye loss due to its hydrolysis, the reactive dyeing was carried out in dichloromethane containing a small amount of water. With only $3m\ell$ of water in $22m\ell$ of dichloromethane, 1.0g of silk fabric could be dyed perfectly. The uptake ratio was increased greatly, compared wish that of normal reactive dyeing in a water medium. It would seem that the one of hydrophobic solvents, dichloromethane, can assist the Even dyeing as it disperses a small amount of dye-dissolved phase and conveys this water phase to the fabric entirely and uniformly.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.296-298
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• 2003

At the water supply field, high voltage induction motor is main facility of a load equipment. The motor is often out of order and its noise, generated heat, loss etc occured occasionally. especially, transmission motor for flux control generates an amount of the harmonics then have a bad influence upon the electric power system. In this study, to analyze the total harmonics distortion of the water supply field receiving high voltage, the harmonics measured and analyzed using the PQA(Power Quality Analyzer) according to the electric power system and electrical load and the reduction method presented.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.257-267
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• 1999

This paper deals with the water cooling system of HVDC(High Voltage Direct CUlTentJ. It is generally accepted that water is a veη effective medium to remove heat losses from any type of equipment. Because of this benefits the water cooling method is used in HVDC. The water cooling system consists of a heat exchanger, circulation pump and a connecting pipe. According to thYI1stor temperature level. thyristor junction temperature is controlled by controlling the f fan of exchanger. In this paper. the water cooling system of HVDC system is analyzed and estimated.

• Journal of the Korean Wood Science and Technology
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• v.46 no.2
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• pp.155-165
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• 2018

The objective of the research was to evaluate the effect of particle pre-treatment on physical, mechanical, and durability of jatropha fruit hulls (JFH) particleboard. The pre-treatments included were immersing in cold water, hot water, and acetic acid solution. After each treatment, the particles were dried up to 3% moisture content. Urea-formaldehyde (UF) resin was used to fabricate particleboards with board size, thickness and density target of 25 cm by 25 cm, 0.80 cm, and $0.70g/cm^3$, respectively. Board pressed at $130^{\circ}C$ for 10 minutes, and $25kg/cm^2$ pressure. The evaluation of particleboard followed the JIS A 5908-2003. Whilist their resistance to subterranean termite test (mass loss, mortality, antifeedant value and feeding rate) refers to the Indonesian standard (SNI 01.7207-2006). The physical and mechanical properties of particleboards showed that all pre-treatments decreased the pH of particles. Overall, all particle immersing treatments resulted of better physical and mechanical properties of particleboard than those of untreated ones. The acetic acid treatment resulted the best physical and mechanical properties of particleboard. Based on the mass loss of JFH particleboard, hot water and acetic acid treated particleboards were classified into weak resistance to subterranean attack. The other two treatments were classified into very weak resistance. Hot water treated particleboard provided the highest mortality and antifeedant as much as 87.40% and 34.20%, respectively. Based on antifeedant classification, hot water treated particleboards were classified into moderately strong resistance, while other treatments were categorized into weak resistance. The lowest feeding rate value ($45.30{\mu}g/termite/day$) was attained by hot water treatment.

• Journal of Institute of Convergence Technology
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• v.7 no.1
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• pp.1-6
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• 2017

The Heat exchanger for deep geothermal system is very important to enhance the efficiency of the system. The co-axial heat exchanger is used due to the limitation of digging space. The heat transfer on the external surface of outer pipe should be high to receive a large amount of heat from the ground. However, the inner pipe should be insulated to reduce the heat loss and increase the temperature of discharge water. This study made experiment apparatus to describe the co-axial heat exchanger and measure the heat transfer coefficients on the internal and external surface. And the pin-fin was designed and fixed on the internal surface to increase the efficiency of heat exchanger. Finally, we calculated the temperature of discharge water using the heat transfer circuit of co-axial heat exchanger and heat transfer coefficient which from experimental results. The water temperature was reached the ground temperature at -500 m and following the ground temperature. When the water return to the ground surface, the water temperature was decreased due to heat loss. As the pin-fin case, the heat transfer coefficient on the internal surface was decreased by 30% and it mean that the pin-fin help to insulate the inner pipe. However, the discharge water temperature did not change although pin-fin fixed on the inner pipe.

• Food Science of Animal Resources
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• v.40 no.3
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• pp.377-387
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• 2020

The aim of this study was to compare the effect of seawater to that of conventional salt (NaCl) on the technological properties of chicken emulsion sausages in a model system. Chicken sausages were prepared with seawater at three levels (10%, 15%, and 20%) in iced water (10%, 5%, and 0%, respectively) or with iced water (20%) and salt (1.2%). There was no difference in pH values and fat loss from emulsion stability between the two treatments. In general, with an increase in the amount of seawater, the water holding capacity (cooking yield and water loss), protein solubility (total and myofibrillar protein), and viscosity were increased. The addition of 20% seawater induced greater (p<0.05) water holding capacity, protein solubility, and viscosity compared to the control sample treated with salt, which was accompanied by an increase in the level of myosin heavy chain protein of samples with 10% and 20% seawater. Furthermore, addition of at least 15% seawater increased all of the main textural properties except for cohesiveness along with the moisture of sausage, whereas the fat and protein contents were decreased. Based on these results, the addition of ≥15% seawater to chicken breast sausage can induce equivalent or enhanced technological properties to those induced with salt, including water holding capacity, protein solubility, viscosity, and textural properties.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.472-476
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• 2019

We have proposed a novel planar lightwave circuit (PLC) optical sensor to monitor the contamination in a flow-cell where water is continuously supplied through a water quality measurement system. We designed a PLC chip with a V-shape waveguide and the simulated its function as a sensor for monitoring contamination in a flow-cell using a numerical the FDTD (finite-difference time-domain) analysis. A novel cross type of waveguide was introduced to make the PLC chip of the V-shaped waveguide. The fabricated PLC was cut into the cross waveguide. A change in the optical propagation loss of the PLC sensor was observed after immersing the PLC sensor into city water. It was determined that the propagation loss of the PLC sensor was 3 dB at a wavelength of $1.55{\mu}m$ in the city water for 15 days.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.51-55
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• 2019

The loss of safety for reservoirs brought about by climate change and facility aging leads to reservoir failures, which results in the loss of lives and property damage in downstream areas. Therefore, it is necessary to provide a Reservoir Failure Forecasting System for downstream residents to detect the early signs of failure (with sensors) in real-time and perform safety management to prevent and minimize possible damage. For the verification of established water level management criteria, 10 water level data up to reservoir capacity was selected. Weight factor and trend line were applied to dramatic increase section of water level in the 1 year period data. The results shows that water level criteria based on three even parts shows less than 7% of standard deviation and it is appropriate to verify management criteria.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.85-85
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• 2020

South Korea experiences few large scale erosion and sedimentation problems, however, there are numerous local sedimentation problems. A reliable and consistent approach to modelling and management for sediment processes are desirable in the country. In this study, field measurements of sediment concentration from 34 alluvial river basins in South Korea were used with the Modified Einstein Procedure (MEP) to determine the total sediment load at the sampling locations. And then the Flow Duration-Sediment Rating Curve (FD-SRC) method was used to estimate the specific degradation for all gauging stations. The specific degradation of most rivers were found to be typically 50-300 tons/㎢·yr. A model tree data mining technique was applied to develop a model for the specific degradation based on various watershed characteristics of each watershed from GIS analysis. The meaningful parameters are: 1) elevation at the middle relative area of the hypsometric curve [m], 2) percentage of wetland and water [%], 3) percentage of urbanized area [%], and 4) Main stream length [km]. The Root Mean Square Error (RMSE) of existing models is in excess of 1,250 tons/㎢·yr and the RMSE of the proposed model with 6 additional validations decreased to 65 tons/㎢·yr. Erosion loss maps from the Revised Universal Soil Loss Equation (RUSLE), satellite images, and aerial photographs were used to delineate the geospatial features affecting erosion and sedimentation. The results of the geospatial analysis clearly shows that the high risk erosion area (hill slopes and construction sites at urbanized area) and sedimentation features (wetlands and agricultural reservoirs). The result of physiographical analysis also indicates that the watershed morphometric characteristic well explain the sediment transport. Sustainable management with the data mining methodologies and geospatial analysis could be helpful to solve various erosion and sedimentation problems under different conditions.