• Journal of the Korean Society for Marine Environment & Energy
• /
• v.6 no.1
• /
• pp.11-20
• /
• 2003

The pollution loads flowing into Mokpo harbour from land in dry case were estimated on the bases of the seasonal flow rates and the seasonal water qualities of streams and effluents located around Mokpo harbour. Average daily amount of fresh water Stowing into Mokpo harbour obtained by the inflow rate data of 4 seasons was found to be about 5.5×10/sup 6/㎥/day and annual inflow rate to be about 2×10/sup 9/㎥/year. The seasonal flow rates of effluents iron Yongsan lake were above 90％ of total flow rates of all inflows in 4 seasons. The concentrations of COD, TSS, TIN and TP at 9 inflow stations Iron streams and effluents in 4 seasons were shown to be in the ranges of 2.87~42.69㎎/ℓ, 3.65~1080.32㎎/ℓ, 0.083~89.744㎎/ℓ and 0.028~6.926㎎/ℓ, respectively. The average loads of COD, TSS, TIN and TP into Mokpo harbour estimated by the data of 4 seasons were found to be about 37 ton/day, 64 ton/day, 13 ton/day and 1.2 ton/day, respectively. The loads of COD, TSS, TIN and TP into Mokpo harbour in summer were shown to be about 82 ton/day, 159 ton/day, 14 ton/day and 2 ton/day, respectively. The main source of pollution loads into Mokpo harbour was found to be the effluent of Yongsan lake.

• Journal of Bio-Environment Control
• /
• v.6 no.1
• /
• pp.48-54
• /
• 1997

Among the various vegetables eggplant and gourd family can stand against high temperature environmental condition, about 35$^{\circ}C$. However, most of greenhouse farmers are giving up crop cultivation during hot summer season due to extreme temperature, 4$0^{\circ}C$ or above, condition of greenhouse interior. To improve this inferior crop growth condition, for nozzle system was installed in the pet greenhouse and the effect of fog system was investigated in order to determine fog water amount and the required fog nozzle numbers according to house volumes. MEE fog nozzle was selected for this Investigation which can produce water particle size of 27${\mu}{\textrm}{m}$ with water amount of 100$m\ell$ at pumping pressure of 70kg/$\textrm{cm}^2$. House cooling test was conducted in the pet greenhouse with one minute fogging and one minute air ventilation without stopping. It maintained 32$^{\circ}C$ at the house interior when the atmosphere and the house temperature were 35 and 4$0^{\circ}C$, respectively. And, an experimental equation was developed through calculating the changes of relative humidity and temperature with psychrometric equation which revealed the moisture transfer pattern between the house air and fog system. It showed that the required water fogging amounts to reduce 1$0^{\circ}C$, 40 to 3$0^{\circ}C$, needs 80.7$\ell$ for 1-2W(8,350㎥) and 99.9$\ell$ for 3-2G-3S(10,330㎥) type greenhouse with particle size of 27${\mu}{\textrm}{m}$.

• Journal of Korean Society on Water Environment
• /
• v.22 no.3
• /
• pp.431-436
• /
• 2006

This study was conducted in the summer of 2005 in Shindong-myeon, Chuncheon-si, Gangwon-do to assess the quality of drinking water and to evaluate their potential pollutants. Ninety four water samples were collected from three classes of water supplies such as simple piped water, supplied own water and others (Supplied local water). Most residents used simple piped water (72.63%). 31.25% residents thought the water quality was bad and landfill was the main source of pollution that affected water quality. To correspond this perception, water quality was measured according to Drinking Water Quality Standard. The general bacteria, coliforms, and $NO_3-N$ exceeded the standard but the water qualities in these four areas were suitable for Drinking Water Quality Standard. The simple piped water showed low mean concentration of excess rate compared to supplied own piped water except general bacteria. Hardness, pH, and $NO_3-N$ showed significantly higher effects on drinking water quality. To evaluate the effect of effluent from landfill, water quality was measured according to distance and altitude. However, there was no effect of landfill effluent. To find out the effect of rainfall, we compared water quality of the year 2003 with that of 2005. The result showed significant differences in hardness and $NO_3-N$ concentration. This study confirmed that $NO_3-N$, coliforms, and general bacteria are main pollutant of water supply in rural community. Therefore, it is necessary to regularly maintain simple piped water supply, supplement sewer facilities, and educate residents about public health risk associated with drinking water in rural area.

• Korean Journal of Ecology and Environment
• /
• v.36 no.2 s.103
• /
• pp.172-180
• /
• 2003

For a biological assessment of Pyeongtaek Reservoir and its major influent streams, an algal growth potential test (AGPT) was conducted with the blue-green algae Microcystis aeruginosa in March, June, September and December, 2000. The range and average value of AGPT were from 0 to 463 mg dw/l and 90 mg dw/l, respectively. For the influent streams in particular, the average of AGPT was the in the Hwangguchi Stream (343 mg dw/l). It decreased to 158, 66, 29, 21, and 21 mg dw/l in the Sojong Stream, Songhwan Stream, Osan Stream, Chinwi Stream, and Ansong Stream, respectively. The AGPT values in the reservoir ranged from 0 to 138 mg dw/1(mean 54 mg dw/1) with a tendency to increase in the upstream, which was close to the influent streams. In general, the AGPT values decreased further in the downstream. Immediately after the abrupt increase in influent discharge in summer, the AGPT value in the downstream almost doubled due to the proliferation of blue-green algae. The water quality of Pyeongtaek Reservoir and its influent streams further deteriorated during the drought period. Similarly, the AGPT value was the highest during this period. The AGPT values showed the closest correlation with the content of P (r = 0.999, p<0,001). Thus, it could be concluded that the content of P is highly effective in the growth of algae. In the Pyeongtaek Reservoir Watershed, the AGPT values varied in space and time. It was also closely related to the nutrient content of influent streams. The AGPT values revealed that the water quality state was hypertrophic (> 20 mg dw/1). Thus, control of the aquatic environment is essential. AGPT is very useful in evaluating the fertility and pollution state of the water as well as determining the nutrients that limit the growth of algae.

• Korean Journal of Ecology and Environment
• /
• v.49 no.4
• /
• pp.334-342
• /
• 2016

In this study, we explain the environmental variables that mainly influence the spatial and seasonal pattern of Galerucella nipponensis in 38 wetland and stream located at mid-low Nakdong River. G. nipponensis were found at total of 32 wetland, was strongly positively correlated with the biomass of Trapa japonica (t=2.173, $r^2=0.013$, p<0.05). In result of seasonal distribution during 3 years, the largest density of G. nipponensis adult were observed in summer (7~8 months), egg and larva was recorded in only early spring (4~5 months). Rainfall were negatively related with the seasonal distribution of G. nipponensis. They were more abundant in dry season (2015 year) than rainy seasons(2013~2014 year). Stable isotope analysis showed that the G. nipponensis consumed as food source no submerged leaf of T. japonica than other plant. However, utilization of T. japonica on Galerucella nipponensis were not influence to plant biomass and/or species composition in vegetated bed. Those considered as adaptive strategies for sustainable habitat maintenance that because T. japonica use as not only food source but also their lives for G. nipponensis.

• Journal of Korea Water Resources Association
• /
• v.52 no.10
• /
• pp.729-742
• /
• 2019

Natural disasters such as floods has been increased in many parts of the world, also Korea is no exception. The biggest part of natural damage in South Korea was caused by the flooding during the rainy season in every summer. The existing flood vulnerability analysis cannot explain the reality because of the repeated changes in topography. Therefore, it is necessary to calculate a new flood vulnerability index in accordance with the changed terrain and socio-economic environment. The priority of the investment for the flood prevention and mitigation has to be determined using the new flood vulnerability index. Total 25 urban districts in Seoul were selected as the study area. Flood vulnerability factors were developed using Pressure-State-Response (PSR) structures. The Pressure Index (PI) includes nine factors such as population density and number of vehicles, and so on. Four factors such as damage of public facilities, etc. for the Status Index (SI) were selected. Finally, seven factors for Response Index (RI) were selected such as the number of evacuation facilities and financial independence, etc. The weights of factors were calculated using AHP method and Fuzzy AHP to implement the uncertainties in the decision making process. As a result, PI and RI were changed, but the ranks in PI and RI were not be changed significantly. However, SI were changed significanlty in terms of the weight method. Flood vulnerability index using Fuzzy AHP shows less vulnerability index in Southern part of Han river. This would be the reason that cost of flood mitigation, number of government workers and Financial self-reliance are high.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.1
• /
• pp.28-34
• /
• 2019

Solar energy is one of the most abundant renewable energy sources on Earth but there are restrictions on the use of solar thermal energy due to the time-discrepancy between the solar-rich season and heating demand. In Europe and Canada, a seasonal solar thermal energy storage (SSTES), which stores the abundant solar heat in the summer and uses the heat for the winter heating load, is used. Recently, SSTES has been introduced in Korea and empirical studies are actively underway. In this study, a $2,000m^2$ flat plate type solar collector and $20,000m^2$ of borehole thermal energy storage (BTES) were studied for a greenhouse in Hwaseong City, which has a heating load of 2,164 GJ/year. To predict the dynamic performance of the system over time, it was simulated using the TRNSYS 18 program, and the solar fraction of the system with the control conditions was investigated. As a result, the solar BTES system proposed in this study showed an average solar fraction of approximately 60% for 5 years when differential temperature control was applied to both collecting solar thermal energy and discharging BTES. The proposed system simplified the configuration and control method of the solar BTES system and secured its performance.

• Korean Journal of Child Education & Care
• /
• v.18 no.4
• /
• pp.65-89
• /
• 2018

Objective: The purpose of this study is to analyze the science concepts and teaching and learning methods presented in the science education-related activities of the Nuri Curriculum teacher guidebooks for ages 3-5. Methods: The research data included 772 activities related to science education in the teachers' guidebook. The analysis of science concepts was based on physical science (force and motion, physical structure, electricity and magnetism, light and shadow, sound properties), chemistry (material properties, material reaction), life science (organizational structure, growth and change, heredity and evolution, animal plant and human relationships), earth science (earth system interaction, earth system structure, and universe), engineering (designed world, engineering design, engineering, technology and society) and ecology (environment preservation). Teaching and learning methods were analyzed according to the types of small and large group activities and of free play activities. Results: Science concepts were mainly presented in the fields of engineering, chemistry, and life science commonly among children aged 3-5, whereas the concepts of physical science were lowly presented in all ages. Science concepts appeared mainly in the daily subjects of 'animal plant and nature', 'life tools', 'environment and life', and 'spring, summer, autumn and winter'. As the teaching and learning method, free paly activities (science area, free outdoor selection activity, math and manipulative activity) were mostly used for the ages of 3 and 4, and small and large group activities (cooking, story sharing, music activity) were for the age of 5. Conclusion/Implications: It is necessary to select the level of science area and concept that can be taught according to the age of children and the timing of the teaching.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.5
• /
• pp.581-588
• /
• 2019

A long-term trend analysis of cold water masses along eastern coast of South Korea was performed during summer, based on wind speed, wind direction, and sea surface temperature (SST) data. Wind data collected over a 22-year period (1997-2011) were compared with another set of data collected over the successive 7-year (2012-2018), highlighting a general decrease in the frequency and speed of south winds. However, both the frequency and speed of these winds have been higher in June between 2012-2018, rather than between 1997-2011. The cold water season between July and August was faster during the 7-year period; moreover, the SSTs registered around Gangneung (EN) rose by $0.5^{\circ}C- 1.8^{\circ}C$, while those around Yeongdeok (EC) and Gijang (ES) increased by only $0.1^{\circ}C-0.3^{\circ}C$. The number of cold water days during the 7-year period, compared to those recorded during previous years (1990-2011, satellite SST data by NOAA/AVHRR), decreased in the proximity of Yeongdeok and Gijang, but increased in the proximity of Kangneung. Additionally, the number of cold water days around Kangneung, Yeongdeok, and Gijang increased in June highlighting a geographical and temporal change in the occurrence of cold waters. These observation can be explained by variations in the pressure distribution that should have weakened the East Asian monsoon, affecting the direction and speed of winds that regulate the flow of cold waters.

• Korean Journal of Environment and Ecology
• /
• v.35 no.2
• /
• pp.98-105
• /
• 2021

Understanding the migration patterns and habitats of juvenile birds during the post-fledging stage is very important for conservation and management of individuals. The Chinese Egret is an internationally protected species. During the wintering season, they inhabit South-East Asia, such as the Philippines, Malaysia, and Taiwan, and breed in China, Russia, and uninhabited islands on the west coast of Korea. IIn this study, we attached a GPS telemetry tracking device to six juvenile Chinese Egrets breeding on Chilsan Archipelago in 2018 and 2019 to identify habitats by analyzing the home range during the post-fledging stage in the summer season. The individual CE1801 moved north and then returned to the Yeonggwang Baeksu tidal flat area, and CE1802 and CE1803 migrated north and inhabited Taean-gun. In 2019, CE1901 showed a similar pattern to CE1801, and CE1902 migrated southward to the Wando-gun area, while CE1903 moved south to the Sinan-gun area then returned to the Yeonggwang Baeksu tidal flat area, showing KDE 50%. The study results confirmed that the Chinese Egret moved broadly around the flat tidal area on the west coast to find a stable habitat during the post-fledging stage. Efforts to protect the habitat, such as limiting the development of this area and restricting human access, are necessary.