• Journal of the Korea Convergence Society
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• v.13 no.2
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• pp.123-129
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• 2022

This study investigated a differences in grade (G), academic performance (AP), and household income (HI) on adolescents' stress (S), peer relationship (PR), and depression (D) in the coal mine area. The study method was to measure S, PR and D according to different of G, AP, HI for 87 middle school students located in Taebaek and Samcheok Dogye area. As a result, there were significant differences in PR in the 2^nd G, and significant differences were shown in PR and D according to HI and AP. Based on these results, it is necessary to expand the support program for PR of middle school students in the coal mine area, and to develop and support active health promotion programs in the community for stress relief and academic activities, especially for low HI.

• Wind and Structures
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• v.35 no.6
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• pp.385-394
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• 2022

The energy demand of the world is increasing rapidly, mainly using fossil energy, which causes environmental damage. The wind is free and clean energy to solve the environmental problems. Thailand is one of the developing nations, and the majority of its energy is obtained from petroleum, natural gas and coal. The objective of this study is to test the characteristics of wind energy at Khon Kaen in Thailand. The wind measurement tools, the 3-cup anemometers to measure wind speed, and wind vanes to measure wind direction, were mounted on a wind tower mast to record wind data at the heights of 60, 90 and 120 meters above ground level (AGL) for 5 years between January 2012 and December 2016. The results show that the annual mean wind speeds were 3.79, 4.32 and 4.66 m/s, respectively. The highest mean wind speeds occurred in June, August and December, in order, and the lowest occurred in September. The majority of prevailing wind directions were from the North-East and South-West directions. The average annual wind shear coefficient was 0.297. Furthermore, five wind turbines with rated power from 0.85 to 4.5 MW were selected to estimate the wind energy output and it was found that the maximum AEP and CF were achieved from the low cut-in speed and high hub-height wind turbines. This important information will help to develop wind energy applications, such as the plan to produce electricity and the calculation of the wind load that affects tall and large structures.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.700-706
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• 2010

Carbon costs, either in the form of a carbon tax or through permit prices in an emissions trading scheme, would ultimately be reflected in higher electricity prices. This price "pass-through" is very critical to the effective design of new policies to curb the amount of carbon emissions. This paper sets out in a structured way the factors that determine price pass-through and how carbon costs would impact on the electricity market and the existing coal-fired power plants. It is shown that pass-through can vary drastically if the underlying dispatch potential of generators varies significantly across alternative emissions reduction scenarios. It can also vary depending on the availability of competing cleaner forms of generation. Pass-through as a measure of business performance is therefore hard to generalize across different circumstances and should be interpreted carefully.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1681-1684
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• 2014

In this paper, in the ventilation system of coal-fired power boilers can measure in real time the fan stall mechanism is all about. The fan stall guard system of boiler airing system of the class of 500MW capacity to protect fan. But because confidence is loosed and operation is influenced by frequent fault of fan stall guard system, confidence is improved by substituting DCS Logic for it.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.97-102
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• 1990

A pilot field study was conducted to measure indoor and personal exposure to carbon monoxide (CO) levels using personal monitors from January to February in 1989. The principal objectives of the study was to design and evaluate the research protocol and the instrumentation performance for application to the conduct of a large-scale personal monitoring program. The mean CO concentrations in kitchen and in bedroom were 23.4 and 11.9 ppm, respectively, while mean concentration of personal CO exposure was 18.9 ppm. It was found that the mean CO concentrations in kitchen exceeded 20 ppm of the Korea ambient CO standard(8-hr average) not to be exceeded more than three times per year. The results suggest that indoor CO levels in Korean houses appear to be affected by use of coal briquette for heating any cooking.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.2
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• pp.125-131
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• 1993

Electrostatic Precipitator has been widely used to get high efficiency which is required for collection of fine particles. In order to provide collection efficiency and size distribution data for a pilot electrostatic precipitator, a pilot study has been conducted on fly ash from pulverized coal burning apparatus. The aims of this study are to investigate characteristics of electric charge, to measure collection efficiency varied with the applied voltage, to get an optimum current and current density. Optimum current density was obtained to 0.7mA/$cm^2$ at the average electric field strength 2.33kV/cm in this experiment. Maximum particle collection efficiency was indicated 99.21% at the applied voltage 7kV. Finally, particle size distribution is also compared with photographic results. Both coarse and fine particles at the range of 0.5$\sim$2$\mu$m and 3$\sim$10 SEM $\mu$m were clearly removed by increasing applied voltage.

• Geomechanics and Engineering
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• v.17 no.2
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• pp.157-164
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• 2019

The effect of electrochemical modification of the physical and mechanical properties of sandstone from Paleozoic coal measure strata was investigated by means of liquid nitrogen physical adsorption, X-ray diffraction and uniaxial compressive strength (UCS) tests using purified water, 1 mol/L NaCl, 1 mol/L $CaCl_2$ and 1 mol/L $AlCl_3$ aqueous solution as electrolytes. Electrochemical corrosion of electrodes and wire leads occurred mainly in the anodic zone. After electrochemical modification, pore morphology showed little change in distribution, decrease in total pore specific surface area and volume, and increased average pore diameter. The total pore specific surface area in the anodic zone was greater than in the cathodic zone, but total pore volume was less. Mineralogical composition was unchanged by the modification. Changes in UCS were caused by a number of factors, including corrosion, weakening by aqueous solutions, and electrochemical cementation, and electrochemical cementation stronger than corrosion and weakening by aqueous solutions.

• Journal of Korean Society for Atmospheric Environment
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• v.3 no.2
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• pp.18-26
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• 1987

In order to investigate the character of air pollution by heavy metals and to elucidate the possible sources in Seoul city, this study was performed to measure the concentrations of heavy metals of total suspended particulate and air pollutants such as $SO_2, NO_2, CO, CH_4$, Non-methane hydrocarbon, ozone at the residential-traffic area (shinchon dong) in January and February, 1986. The results are as follows: 1. $SO_2$ and TSP concentration were 135ppb and 167 $\mug/m^3$ in average, respectively. 2. While concentrations of heavy metals such as Fe, Cu, Pb in the ambient air seems gradually decreasing annually, Ni compound has been shown the tendency of increasing. 3. Among heavy metals in TSP analysed, the iron was detected at the highest level, 0.905% and the cadimium was the lowest 0.004% in average, respectively. 4. V, Fe and Zn compounds in air were observed to be highly correlated with their correlation coefficients(r) higher than 0.7. Pb compound was highly correlated to the levels of Zn and Fe, however relatively less correlated to V compound. 5. Among concentrations of heavy metals in the particulates, V and Ni compounds were highly correlated with coefficient(r) of 0.8587; the cause might be imagined by the fact of releasing from combustion of fuel oil. Fe, Pb and Zn compounds were highly correlated $SO_2$ concentration. It might be explained that they were released by combustion of coal. 6. The level of $SO_2$ was highly correlated to most of heavy metals: especially correlation coefficient(r) to Pb compound was 0.9081. Pb compound was also highly correlated to NO, CO and TSP. TSP showed higher correlation to Pb and Cd compounds than to V and Ni compounds. It might be assumed that particulate was mainly produced by combusting coal from space heating and by exhausting gasoline and diesel oil from transportation rather than by burning fuel oil.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.67-73
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• 2015

Almost base-loaded power plants such as flaming coal and nuclear energy require large-scale transmission facilities (LTFs) in order to send electricity to remote consumption areas. As well known, LTFs incur various social costs. However, a decentralized generation source such as integrated energy business (IEB)-based combined heat and power (CHP) plant is located in nearby electricity-consuming area, and thus it does not demand LTFs, providing the benefits from avoiding the damages caused by them. This study attempts to measure the benefits of avoiding the damages from the LTFs by the use of the contingent valuation (CV) method. To this end, a national survey of randomly chosen 1,000 households was implemented and the public's willingness to pay (WTP) for substituting consumption of electricity generated from flaming coal-fired power plant, currently a dominant generation source in Korea, with that produced from IEB-based CHP plant. The results show that the WTP for the substitution is estimated to be about 41.4 won per kWh. Considering that this value amounts to 33% of the average price of residential electricity in 2014, the external benefit of the IEB-based CHP as a decentralized generation appears to be large.

• Journal of Environmental Impact Assessment
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• v.16 no.2
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• pp.143-156
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• 2007

This study has researched the management status and the pollution level of water, soil, stream sediments of 11 abandoned coal mines out of a total of 12 within Obong-Dam area except Bukyung mine, which was submerged when constructing Obong-Dam, and selected areas which are in needs to have pollution control facilities in the first place. From the results of examination on the runoff at the waste rock pile and mineheads, the runoff from Sueun mine (pH, Fe, Al), Samwon mine (pH, Al), Wangdo mine (pH, Al), Mose mine (pH, Fe, Al) and Daeryeong mine (pH) exceeded the permissible discharge standards of the water quality, but the water at merging point with Obong-Dam after joined with Doma branch satisfied both Water Quality Standards and Drinking Water Quality Standards. In regard to groundwater contamination, it is found that areas where exceeded the Drinking Water Quality Standards are Wangdo mine (pH), Jangjae mine (pH, Zn), Daeryeong mine (pH) whereas all areas satisfied Soil Contamination Warning Standards of Soil Environmental Conservation Law. When comparing a research result on underwater sediments of branches of abandoned mines to the EPA Guidelines for classification of great lakes harbor sediments, Dongguk Gaerim (Fe), Jungwon mine (Fe), Daebo mine (Mn), Samwon mine (Mn) and Daeryeong mine (Mn) showed mid-level of contamination, whereas Sueun (Fe, Mn), Daebo mine (Fe), Woosung mine (Fe, Mn), Wangdo mine (Fe, Mn), Mose mine (Fe) and Daeryeong mine (Fe) showed high-level of contamination. In addition, contamination levels of underwater sediments in Wangsan and Doma branch where abandoned mine's branches merge together, Wangsan branch showed no contamination at all whereas Doma branch shows mid-level of contamination which reflect the Doma branch is affected by waste rock pile and minehead runoff of the abandoned mines in the Doma branch area. It is concluded that Mose mine and Sueun mine required treatment of acid mine drainage. and Wangdo, Jungwon, and Samwon mines were in need of mine tailing and erosion control work. The Samwon mine additionally required a control system for closed minehead runoff. Although the Samwon mine reached a high concentration of Al, Mn $Ca^{2+}$, $SO{_4}^{2-}$ in the runoff, the levels decreased after it was combined with a tributary. It has been concluded that after further monitoring of the cause of pollution, a preventive measure system may be needed to be built.