• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.1
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• pp.29-36
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• 2017

The paper presents a basic investigation for the development of cleaning technology employing an annular nozzle ejector for application to cleaning water supply and air bubble generation. The quantitative flow characteristics of the primary and suction flows, the qualitative visualization behavior of the mixed jet, and the percentage concentration of pesticide residual at different values of the ejector screw pitch were investigated. It was seen that the primary flow rate increased, while the mass ratio decreased with increase in screw pitch. Further, the mixed jet behaved like a buoyancy jet or horizontal bubbly jet, and the residual concentration of pesticide first decreased and then increased with increase in screw pitch.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.4
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• pp.402-407
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• 2014

In this paper, residual sway control of objects that are moved underwater is investigated. The fuel transfer system in a nuclear power plant transfers the nuclear fuel rods underwater. The research on the dynamics of the loads transferred in different mediums (water and air) and their control methods have not been fully developed yet. The attenuation characteristics of the fuel transfer system have been studied to minimize its residual vibration by considering the effects of hydrodynamic forces acting on the fuel rod. First, a mathematical model is derived for the underwater fuel transfer system, and then experiments have been conducted to study the dynamic behavior of the rod while it travels underwater. Lastly, the residual vibration at the end point is minimized using the input shaping technique.

• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.111-114
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• 2005

In this the study, polyester/cotton(P/C) blended fabrics with fine denier were developed to get the light weight compared with the traditional P/C blended fabrics. Moreover, the width of the fabrics was extended by the tenter during the final heat treatment to get the lower fabric density and lighter weight. Then, the physical properties of these fabrics were analysed. The results were as the follows: The developed fabrics had 22.6-31.6% lighter weight than the traditional fabrics with the same fabric width. The weight of fabric decreased drastically with the fabrics width down to 67.1 $g/m^2$. The fabric density for the warp direction decreased with the fabric width. The tenacity and the elongation of the developed fabrics was little lower than that of the traditional fabrics. The air permeability of the developed fabrics increased with that of the traditional fabrics. The stretch rate of the developed fabrics decreased with increasing the fabric width. Residual stretch rate of the developed fabrics was more stable than that of the traditional fabrics. Residual stretch rate of the developed fabrics increased with the fabric width, but the highest value was less than 5% which is quit stable.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.271-277
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• 2010

Intravenous(IV) drip therapy is extensively used for all kinds of treatments. It works by delivering medicine directly into the vein. When the medicine has been fully dispensed, a dangerous situation occurs since air in the IV drip bag could enter the patient's vein, which is hazardous to the patient’s safety. In this paper, using capacitive sensors to detect the residual quantity of a plastic IV drip pack is proposed. A simulation model of this technology was shown by a finite elements analysis(FEA) program to find out its feasibility and analyze the proper geometrical dimension of a capacitive sensor. According to the FEA simulation, 3 kinds of capacitive sensors were attached to the bottom surface of the plastic IV drip bag to detect the residual quantity in the experiment. Experimental data showed an agreement with the FEA simulation model estimation and confirmed that the sensor works.

• Journal of Power System Engineering
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• v.15 no.6
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• pp.67-72
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• 2011

In the present study, crack healing effect and residual stress of $Al_2O_3$ ceramics were investigated by changing the sintering temperature and heat treatment conditions. And also it was investigated that the influence of different filler loadings of nano-sized SiC particles on the crack healing behavior of $Al_2O_3$ ceramics. The test samples were characterized by three point bend flexural tests to evaluate their mechanical properties. The morphological changes were studied by FE-SEM and EDS. The test results indicated that the $Al_2O_3$ with nano-sized SiC ceramics sintered at $1800^{\circ}C$ were showed highest density. Sintering temperature at $1800^{\circ}C$, the bending strength of heat treatment in air atmosphere specimens showed about 42 % increment in comparison to the un-heat treated specimens. The cracked specimens can be healed by heat treatment in vacuum atmosphere but the crack healing effect of $Al_2O_3$ ceramics, which is heat treated in air atmosphere was higher than that of heat treated in vacuum atmosphere. $Al_2O_3$ with 30 wt% of SiC ceramics indicated higher crack healing ability than that with 15 wt% of SiC ceramics. The FE-SEM images showed that the median cracks and pores were disappeared after heat treatment in air.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.459-468
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• 2015

Deposits discharged through the cleaning mainly were cement mortar, bitumen paintings and rust pieces, and fragments of perforation, stones and gravels. Deposits were more removed through swabbing pig cleaning rather than air scouring cleaning on the whole. However, air scouring cleaning were not influenced by the constraint conditions such as a change in the diameter or the presence of the valve in water mains compare to swabbing pig cleaning. So, it was thought that air scouring cleaning might be more favorable to water distribution network cleaning in the future. After the cleaning, water quality including residual chlorine and turbidity also was improved because of the removal of a significant amount of the deposits. Therefore, if the cleaning is continuously and regularly implemented in water mains, it is expected that it will help to recover the reliability and to preserve the health of water quality.

• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.515-530
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• 2009

Evaporation from surface water bodies is influenced by a number of meteorological parameters. The rate of evaporation is primarily controlled by incoming solar radiation, air and water temperature and wind speed and relative humidity. In the present study, influence of weekly meteorological variables such as air temperature, relative humidity, bright sunshine hours, wind speed, wind velocity, rainfall on rate of evaporation has been examined using 35 years(1971-2005) of meteorological data. Statistical analysis was carried out employing linear regression models. The developed regression models were tested for goodness of fit, multicollinearity along with normality test and constant variance test. These regression models were subsequently validated using the observed and predicted parameter estimates with the meteorological data of the year 2005. Further these models were checked with time order sequence of residual plots to identify the trend of the scatter plot and then new standardized regression models were developed using standardized equations. The highest significant positive correlation was observed between pan evaporation and maximum air temperature. Mean air temperature and wind velocity have highly significant influence on pan evaporation whereas minimum air temperature, relative humidity and wind direction have no such significant influence.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.8
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• pp.780-788
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• 2005

Two different types of algorithms were developed and applied to detect the partial faults of a multi-type air conditioning system. Partial faults include the compressor valve leakage, the refrigerant pipe partial blockage, the condenser fouling, and the evaporator fouling. The first algorithm was developed by using mathematical models and parity relations, and the second algorithm was developed by using mathematical models and a RBF neural network. Test results showed that the second algorithm was better than the first algorithm in detecting various partial faults of the system. Therefore, the algorithm developed by using mathematical models and a RBF neural network may be used for the detection of partial faults of an air-conditioning system.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.4
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• pp.193-202
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• 2022

Manholes and underground spaces are installed to manage the buried heat transport pipes of the district heating system, and the corrosion damage of the equipment placed in this space often occurs. The purpose of this work is to identify locations with a high risk of corrosion damage in the air vent and to establish preventive measures based on precise analysis via sampling of heat transport pipes and air vents that have been used for about 30 years. The residual thickness of the air vent decreased significantly by reaching ~1.1 mm in thickness, and locations of 60~70 mm away from a transport pipe were the most vulnerable to corrosion. The energy dispersive X-ray spectroscopy (EDS) analysis was performed in the corroded oxides, and it was found that chloride ion was contained in the corrosion products. Anodic polarization tests were carried out on the air vent materials (SPPS250, SS304) with varying the amounts of chloride ions at two different temperatures (RT, 80℃). The higher concentration of chloride ions and temperature are, the lower corrosion resistances of both alloys are.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.29-30
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• 2020

As the modern society enters, the building becomes sealed and the public's interest in the environment increases, so the interest in indoor air pollution increases and the environmental pollution is raised as an important issue not only outdoors but also indoors. In addition, the emergence of sick house syndrome (SHS) has increased the interest in formaldehyde and is a cause of deteriorating indoor air quality. Accordingly, this study prepared a functional paint by incorporating a photocatalyst in an aqueous paint, and conducted formaldehyde adsorption experiments and functional evaluation. As a result of the experiment, as the photocatalyst was added, the formaldehyde adsorption performance tended to increase. In addition, as a result of measuring the impact resistance and alkali resistance according to the KS standard, there is no difference in residual cracks and cracks between the water-based paint without the photocatalyst and the water-based paint with the photocatalyst added. Therefore, it is considered that the water-based paint added with a photocatalyst can improve the indoor air quality by adsorbing formaldehyde and can be used as a functional paint because the functionality is not different from that of a general water-based paint.