• Journal of Advanced Marine Engineering and Technology
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• v.35 no.3
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• pp.329-334
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• 2011

The cooling water circulation plates had been used to drop the temperature of refractory outside shell of common cooling system by using cooling plate or stave type. When they are attacked by surrounding gas, they are corroded and the water flows in the refractory due to leakage of water. So, the life of refractory material is shortened and changed due to the worse conditions of cooling system. The automatic sensing device for water leakage of cooling plate is developed to check the position of trouble by using the microprocessor system when cooling water leak and gas are flowed into the cooling plate through the leakage position. The flowed gas is detected in the micro-process system which delivers the detected position of cooling plate or stave to main control room through the wireless-radio relay station. This system can be possible to detect the position of cooling plate or stave against the water leakage part immediately and then deliver the signal to main control room by using the microprocessor system and wireless-radio relay station. This system will be developed in changing the working condition from manual system to unmanned auto alarm system.

• Environmental Engineering Research
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• v.23 no.2
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• pp.150-158
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• 2018

The deteriorating role of Nakdong River due to the Four Major Rivers Project has caused a series of problems, including water pollution, drying streams, aggravation of the hydroecology. Geumho River and Gyeongseong-cheon had a higher concentration index and is believed to impact the water quality of the main stream. The influence index of Geumho River and Nam River between 2015 and 2016, which have a large amount of discharge, was the highest among the tributaries in terms of the load material balance. Showing the highest average concentration and average load in the index assessment, Geumho River is believed to require an intensive management for improving the water quality of the main stream. Furthermore, when the cumulative percentage of the average concentration and average load was compared based on the water quality improvement of the tributaries mixed to Nakdong River, which was set to 60%, Geumho River, Nam River, Topyeong-cheon, and Cha-cheon, which showed the highest ratio in that order, were determined to require a water quality management program as a priority.

• Journal of Environmental Impact Assessment
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• v.12 no.4
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• pp.259-270
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• 2003

To investigate the water quality and the pollution state of lower Yeongsan river system, 38 water samples were taken from the main stream of the Yeongsan river, Gomakwon and Hampyeong streams of the system in dry and flood seasons, May and August, 2001. The Yeongsan river is typically natural in accordance with pH-& diagram. But the chemistry based on Piper's diagram indicates that the river is influenced by seawater. BOD increases as the sampling sites are approaching the downstream in Gomakwon and Hampyeong streams overwhelming WQS V grade of 12.40mg/l. T-N and T-P of the river are mainly loaded not in above branch streams but in the main stream of the river, which are caused by manure for farming, domestic animal discharges and life-sewage, in possible. Meanwhile, heavy metal contents are below WQS or not detect in whole water samples. So, it shows that the above river waters be polluted by not industrial but life/agricultural foul waters.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.227-233
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• 1999

This study is mainly concerned with phenomenon of cavitation-erosion on the several materials and corrosive liquids which were applied with vibrator (suggested by ASTM G-32, 20KHZ, 24{$mu}m$).The main results obtained are summarized as follows ; (1) The maximum erosion rate by cavitation erosion in both of fresh-water and sea-water appeared to be proportioned to their hardness and tensile strength. (2) Cavitation weight loss and rate of cast iron in sea-water condition were greater (approximately 3 times) than that in distilled-water condition, however in case of stainless and brass the cavitation weight loss and their rates were not so different in both of their conditions. (3) Cavitation weight loss of composite materials were shown as below on this test, DuraTough DL : Weight loss in sea-water condition were greater (approximately 2.3 times) than it's fresh-water condition. (4) As the result of observation with digital camea of specimens, the main tendency of cavitation erosion for metals, was that small damaged holes causing by cavitation e개sion was appeared with radial pattern, and composites materials was that small damaged holes were appeared randomly.

• Proceedings of the Petrological Society of Korea Conference
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• 2000.05a
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• pp.3-11
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• 2000

The earth environment consists of four spheres : geosphere, hydrosphere, atmosphere and biosphere. The geosphere consists mostly of minerals. It, however, contains some water and air in its shallow depth. Although hydrosphere and atmosphere consist predominantly of water and air, respectively, both contain some minerals. The biosphere consisting of various organisms is present in the interfaces of geosphere, hydrosphere and atmosphere. The natural environment of the earth is continuously changing by the interaction of four spheres. It suggests that out relevant environmental problems can not be revolved without understanding the natural relationship of these four spheres. Minerals in our environment are very important because they are the main constituent materials of the earth and they control our environment. The roles of minerals in our environment have not been understood even in the scientific society. Thus their roles have been neglected. Review of studies on the environmental mineralogy so far made at our laboratory and others show that minerals control the environment in various ways. Minerals neutralize the acid water as well as acid rain. Minerals in soils and rocks are major neutralizer of the acid rain. Salinization of sea water is attributed to the ionic substitution between minerals and sea water. Some minerals control the humidity of the air. Corals, the products of biomineralization, are the main carbon controller of the air. Minerals also adsorb heavy metals, organic pollutants and radioactive nuclides. Such remarkable functions for controlling the environment come from the mineral-water reaction and biomineralization. All these phenomena are subjects of the environmental mineralogy, a new field of earth science.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.1
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• pp.1-8
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• 2007

Environment factors related to the distribution of organic matter in surface seawater and sediments were investigated to estimate main pollution sources and range of their influence in Gwangyang Bay. The main pollution sources for the factors that affect organic matter distribution could be divided into three main sources: fresh water runoffs from Seomjin and Dong River, Gwangyang-si domestic sewage, and Yosu Industrial Complex. Considering the characteristics in horizontal distributions of the environmental factors in water column, sediment, and water current regime, the influencing range of these main sources was likely to be divided into three areas within the bay as follows: Area I receiving lots of fresh water from Seomjin River, Area II receiving lots of domestic sewage from Gwangyang-si and fresh water of Dong River, Area III receiving lots of materials from Yosu Industrial Complex. Area I seems to be characterized as low salinity, high concentration of $NO_3-N,\;and\;SiO_2-Si$, Area II as low salinity, high concentration of $NO_3-N,\;NH_4-N,\;and\;SiO_2-Si$, and Area III as high water temperature, high concentration of $NH_4-N,\;and\;PO_4-P$ in water column, high concentration of $NH_4-N,\;PO_4-P,\;and\;SiO_2-Si$ in surface sediments.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.4
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• pp.137-147
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• 2011

This study aims to find out the construction process and planning characteristics of Suwon and Hwa-sung in 18th century from the point of water system. This study has an explanatory approach. The planning intents in the water system was driven out by analyzing various planning elements in relation to water system in the process of constructing Hwa-sung in 18th century. Using Entire Map of Hwa-sung, land registration map made in 1911 and topographic map of 1/10,000 scale made in 1917, water system and interpretation of spatial structure in Hwa-sung were analyzed. The results are as follows(Planning characteristics of the water system in Haw-sung in 18th century are as follows). Firstly, in determining the spatial structure and location of Hwa-sung, water system had an important role. Secondly, integrated drainage system was planned by the organization of natural and artificial water stream. Thirdly, the main street system and land use structure were planned in relation with water system. Fourthly, territoriality of main area was planned with water stream. Fifthly, ponds were constructed for flood control and they had important role as landscape elements. Sixthly, water stream was used as intentional BiBo element. As a result of the study, the weater system of Hwa-sung in 18th century was planned by the organization of natural and artificial water stream in relation with the location of new town and wide area's spatial structure, street system, land use structure, territoriality of main area, terriflood control, water quality protection, landscape, 비보 and urban daily life.

• Journal of Korea Water Resources Association
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• v.37 no.8
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• pp.623-630
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• 2004

In this paper, the hydraulic model tests are conducted for the hydraulic characteristics at channel junctions. The experiments are examined through the variation of approaching angle, discharge in the upstream main channel and the discharge ratio between the main channel and the tributary. The experiments are conducted in the channel model having the length of 450cm, the widths of 40cm and 32cm. Four water tanks and pumps are installed in the experimental channel. The length of stagnation zone is increased by Increasing of approaching angle and the discharge in the upstream channel. The length of stagnation increase with the discharge ratio between the main channel and the tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. Accelerating zone of the velocity is occurred in the middle of the channel in the small approaching angle. However, the influence zone of the accelerating velocity is increased by increasing the approaching angle.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.30-36
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• 1993

Wood chips of oak (Quercus mongolica) and larch (Larix leptolepis) were treated with a relatively low pressure steam(10~20 kg/$cm^2$) for 10~20 min (first-stage),and then increased pressure up to 30kg/$cm^2$ for 30 second (second-stage), and steam pressure was released intentionally to air. Main components of exploded wood were separated with 1% NaOH and hot water-methanol. In this work, the more effective low pressure explosion condition and separation method of wood main component were investigated. The results can be summarized as follows; 1. The yields of exploded wood were generally decreased with increasing steam pressure and reaction time. 2. The proper condition of steam explosion in low pressure for the separation of wood main components was 15kg/$cm^2$-10 min, in oak wood and 20kg/$cm^2$-10 min., then 30kg/$cm^2$-0.5 min, in larch wood. 3. The 23% of elude hemicellulose was obtained from the exploded oak wood which was treated with optimal condition. 4. In the case of hot water-methanol extraction, the ratio of delignification was 14~23% in the exploded larch wood and 42~55% in the exploded oak wood. 5. The methanol was more effective than 1% sodium hydroxide solution for extraction of lignin from exploded wood.

• Journal of Korean Society on Water Environment
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• v.37 no.2
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• pp.114-127
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• 2021

Water pollution in the lower reaches of the Namhan River is getting worse due to drought and a decrease in water quantity due to climatic changes and hence is affecting the water quality of Paldang Lake. Accordingly, we have used a water quality index (WQI) and statistical analysis in this study to identify the characteristics of the water quality in the lower reaches of the Namhan River, the main causes of water pollution, and tributaries that need priority management. Typically, 10 items (WT, pH, EC, DO, BOD, COD, SS, T-N, T-P, and TOC) were used as the water quality factors for the statistical analysis, and the matrix of data was set as 324 × 10·1. The correlation analysis demonstrated a strong correlation between Chemical Oxygen Demand (COD) and T-P with a high statistical significance (r=0.700, p<0.01). Furthermore, the result of principal component analysis (PCA) revealed that the main factors affecting the change in water quality were T-P and organic substances introduced into the water by rainfall. Based on the Mann-Kendall test, a statistically significant increase in pH was observed in SH-1, DL, SH-2, CM, and BH, along with an increase in WQI in SH-2 and SM. BH was identified as a tributary that needs priority management in the lower reaches of the Namhan River, with a "Somewhat poor" (IV) grade in T-P, "Fair" grade in WQI, and "Marginal" grade in summer.