• Hwankyungkyoyuk
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• v.20 no.2
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• pp.93-107
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• 2007

Livestock agriculture plays an essential role Hongsung's economy. Unfortunately, if manure is manage properly it can contaminate water and pollute the air. The purposes of this study were to provide awareness of environmental impact and to design educational programs with sustainable agriculture. I used the specific steps of processes. First, collecting informations through survey on environmental awareness of livestock farmers in Hongsung-gun and recognizing the tendencies. Second, analyzing on educational status of livestock farmers. Third, finding objectives of environmental educational programs. At the end of processes, establishing programs which concerning on environmental education. I used two research methods to gather and analyze the data for developing an environmental education program. The first one is a general survey among 50 livestock farmers from Hongseong-gun, Chungcheongnam-do. The second one is the in-depth interviews with specialists in environmental education and government officials from the central government - the Ministry of Agriculture and Forestry - and the local government - Hongsung-gun who are in charge of livestock farming. I found the following results from this research. First, most livestock farmers replied with 'highly likely' to the five items on the recognition of the necessity of environment preservation, whereas only 38.7% answered with 'likely' to the item on the environmental pollution caused by livestock farming. This shows the tendency that they have less recognition of the reality than necessary. Second, most of the contents among 5 areas(knowledge, recognition, function, attitude, and participation) are the knowledge areas. That results are analyzed training materials for livestock farmers made by Hongsung-gun in 2004 and in 2005 by using goal categories suggested in the Tbilisi Resolution. Third, after analyzing the survey and in-depth interviews, I found that the need for education to recognize the environmental pollution, environmental protection and recycling of the livestock waste. We can summarize conclusions from this research. First, we need on educational program improve the livestock farmers' recognition of importance in environmental protection. Second, it is necessary to develop educational program with the viewpoint that livestock waste is not one of the culprits of the environmental pollution, but a recyclable resource. Third, contents of the environmental education program, should include all the educational elements, namely, knowledge, recognition, attitude, function and participation. The education for livestock farmers requires a research on the environmental education program that can be used with crop farmers who can use the resources recycled from the livestock waste from the viewpoint of recycling resources. This research is focused on the collection and analysis of the basic data for developing an environmental education program and the composition of the program. A further research on the implementation and assessment of this program is required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.718-723
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• 2016

The use of the scroll compressor in the air conditioning of medium-sized vehicles has increased because of its low torque fluctuation, high energy efficiency and low noise. In addition, the main components of the compressor have been changed from steel to aluminum to reduce its weight, following studies on the constituent materials. The processing precision of the fixed scroll and orbiting involute scroll wrap of the scroll compressor must be below $10{\mu}m$. To ensure this, the surface roughness and contour tolerance are measured. To improve the hardness of the orbiting scrolls using aluminum subjected to anodizing treatment and as the base material, we used a sealing treatment and measured the resulting characteristics. The aluminum materials were made of an Al-Mg-Cu based alloy including small amounts of Ni, Fe, and Zn. The surface roughness was less than $3{\mu}m$ and the processing accuracy was within $10{\mu}m$. Also, the hardness of the nanodiamonds with CNTs used in the sealing treatment was more than 450. This was found to improve the hardness of the material by 50% or more compared to the water sealing treatment and there was little difference between the use of carbon nanotubes and nanodiamonds as sealing materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.142-149
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• 2019

In this study, the past erosion history and current status in the CHUNG-UI beach of Eulwang-dong, Jung-gu, Incheon-Si, South Korea were investigated and analyzed the wave with wave-induced current to investigate the causes of coastal erosion. As a result, the significant wave height ($H_{1/3}$) was in the range of 0.07~1.57 m and the mean value was 0.21 m. The maximum wave height ($H_{max}$) was in the range of 0.02-4.76m and the mean value was 0.27m. The vertical wave height and cycles were estimated through numerical model experiments of wave transformation. The 50-year frequency design wave height ranged from 0.82m to 3.75m. As a result of the experiment of wave-induced current, wave-induced current in the CHUNG-UI beach was decreased after the installation of the Detached breakwater and the Jetty. On the other hand, when the crest elevation was increased up to 5 m, there was no significant change, but when the crest elevation was increased to 8m, strong wave-induced current occurred around the submerged breakwaters due to lowered depth of water. In addition, the main erosion of the CHUNG-UI beach is due to the intensive invasion of the wave characteristics coming from the outer sea into the white sandy beach. The deformation of the wave centered on the front of the sandy beach caused additional longshore currents flowing parallel to the sandy beach and rip currents in the transverse direction, thus confirming that the longshore sediment was moved out of the front and out of the sea. The results of this study can be used as preliminary data for the recovery of the sand and the selection of efficient erosion prevention facilities.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.596-608
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• 2018

As urban infrastructure is aging, the possibility of accidents due to the failures or breakdowns of infrastructure increases. Especially, aging underground infrastructures like sewer pipes, waterworks, and subway have a potential to cause an urban ground sink. Urban ground sink is defined just as a local and erratic collapse occurred by underground cavity due to soil erosion or soil loss, which is separated from a sinkhole in soluble bedrock such as limestone. The conventional measurements such as differential settlement gauge, inclinometer or earth pressure gauge have a shortcoming just to provide point measurements with short coverage. Therefore, these methods are not adequate for monitoring of an erratic subsidence caused by underground cavity due to soil erosion or soil loss which occurring at unspecified time and location. Therefore, an alternative technology is required to detect a change of underground physical condition in real time. In this study, the feasibility of a novel magnetic resonance based monitoring method is investigated through laboratory tests, where the changes of path loss (S21) were measured under various testing conditions: media including air, water, and soil, resonant frequency, impedance, and distances between transmitter (TX) and receiver (RX). Theoretically, the transfer characteristic of magnetic field is known to be independent of the density of the medium. However, the results of the test showed the meaningful differences in the path loss (S21) under the different conditions of medium. And it is found that the reflection coefficient showed the more distinct differences over the testing conditions than the path loss. In particular, input reflection coefficient (S11) is more distinguishable than output reflection coefficient (S22).

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.213-220
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• 2018

BACKGROUND: This study was carried out to determine characteristics of residual pesticides in time-dependent manner and calculate half-lives of the residual pesticides in fresh and dried Chinese matrimony vine. In addition, processing factors were calculated based on the residual concentrations in them. METHODS AND RESULTS: The test pesticides, etofenprox and fenitrothion, were sprayed onto the Chinese matrimony vine plants at once or twice (at seven-day interval) and then samples were collected at 0 (after 3 hours), 1, 3, 5 and 7 days after the last spraying. Dried samples were prepared in hot-air drying oven at $60^{\circ}C$ for 48 hours until water content of less than 20%. Residual concentrations of etofenprox in fresh and dried samples decreased by 54.0-60.9% after 7 days of the last pesticide-application. In case of fenitrothion, the concentrations were found to have decreased by 69.2-76.5%. Processing factors of etofenprox were 2.6-3.0 for the one-time spraying and 2.5-3.0 for the two-time spraying and those of fenitrothion were found to be 1.5-22 for the one-time spraying and 1.6-2.0 for the two-time spraying. First half-lives of etofenprox and fenitrothion in fresh and dried samples ranged from 5.0 to 6.3 and from 3.4 to 4.0 days, respectively. The third half-lives were found to be 15.0-18.9 and 10.2-12.1 days, respectively. CONCLUSION: Residual concentrations of the tested pesticides in the studied crop decreased, but those in the dried samples appeared to have increased. In addition, processing factor and half life were constant regardless of spraying times.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.542-547
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• 2021

Glass lined impellers are corrosion resistant to most chemicals, including strong acids, and also have a smooth, non-stick surface, easy to clean and free from impurities in the process. Glass lined home base impeller is a multi-purpose impeller designed to stir a wide viscosity range of liquids from low viscosity fluids to high viscosity fluids, among others, cell culture, yeast culture, and beer fermentation pots, especially used for air-water system breathable stirring. The glass lining for HB impellers, which are simple in structure and competitive in performance, is essential to have upper and lower division in order to make the joint area between the impeller and shaft as small as possible. The upper and lower division of the impeller hardly affects the mixing performance, but the aeration performance. In this study, in order to optimize the shape of the Glass Lining HB impeller, a study was conducted on the effect of the angle between the upper and lower impellers, the clearance between the impellers, and the number of baffles on the aeration power. The optimal shape and baffle plate conditions for the Glass lined HB impeller were derived through the study results that the angle and the clearance between the upper and lower impellers decreased the ration of the power consumption with aeration P_g and that without aeration P₀, P_g/P₀.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.44-53
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• 2021

Urban stormwater runoff contains heavy metals that accumulate in on-site treatment systems, thus resulting to facility deterioration and maintenance problems. In order to resolve these problems, low impact development (LID) technologies that promote natural materials circulation are widely used. LID facilities are capable of treating heavy metals in the runoff by means of plant uptake; however, the uptake or phytoremediation capabilities of plants have not been studied extensively, making it difficult to select the most suitable plant species for a certain LID design. This study investigated the vegetative components of an LID facility, roadside plants, and plants in landscape areas with different heavy metal exposure and frequency to determine the uptake capabilities of different plant species. The plants harvested inside the LID facilities and roadsides with high vehicular traffic exhibited greater heavy metal concentrations in their tissues as compared with the plants in landscape areas. Generally, the accumulation of heavy metals in the plant tissues were found to be influenced by the environmental characteristics (i.e. influent water quality, air pollution level, etc.). Dianthus, Metasequoia, Rhododendron lateritium, and Mugwort were found to be effective in removing Zn in the urban stormwater runoff. Additionally, Dianthus, Metasequoia, Mugwort, and Ginkgo Biloba exhibited excellent removal of Cu. Cherry Tree, Metasequoia, and mugwort efficiently removed Pb, whereas Dianthus was also found to be effective in treating As, Cr, and Cd in stormwater. Overall, different plant species showed varying heavy metal uptake capabilities. The results of this study can be used as an effective tool in selecting suitable plant species for removing heavy metals in the runoff from different land use types.

• ALGAE
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• v.37 no.2
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• pp.149-161
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• 2022

Noctiluca scintillans is a heterotrophic dinoflagellate that causes red-colored oceans during the day (red tides) and glowing oceans at night (bioluminescence). This species feeds on diverse prey, including phytoplankton, heterotrophic protists, and eggs of metazoans. Thus, many scientists have conducted studies on the ecophysiology of this species. It is easy to cultivate N. scintillans at a scale of <1 L, but it is difficult to cultivate them at a scale of >100 L because N. scintillans cells usually stay near the surface, while prey cells stay below the surface in large water tanks. To obtain mass-cultured N. scintillans cells, we developed an automatic system for cultivating N. scintillans on a scale of 100 L. The system consisted of four tanks containing fresh nutrients, the chlorophyte Dunaliella salina as prey, N. scintillans for growth, and N. scintillans for storage, respectively. The light intensities supporting the high growth rates of D. salina and N. scintillans were 300 and 20 µmol photons m^-2 s^-1, respectively. Twenty liters of D. salina culture from the prey culture tank were transferred to the predator culture tank, and subsequently 20 L of nutrients from the nutrient tank were transferred to the prey culture tank every 2 d. When the volume of N. scintillans in the predator culture tank reached 90 L 6 d later, 70 L of the culture were transferred to the predator storage tank. To prevent N. scintillans cells from being separated from D. salina cells in the predator culture tank, the culture was mixed using an air pump, a sparger, and a stirrer. The highest abundance of N. scintillans in the predator culture tank was 45 cells mL^-1, which was more than twice the highest abundance when this dinoflagellate was cultivated manually. This automatic system supplies 100 L of N. scintillans pure culture with a high density every 10 d for diverse experiments on N. scintillans.

• Journal of Korea Port Economic Association
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• v.38 no.4
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• pp.139-169
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• 2022

This study derived determinants of 'Decent Work' in the logistics industry and aims to use the analysis results as basic data for policymaking related to labor in the logistics industry and to prepare policies suitable for the characteristics of the logistics industry. As the dependent variable of the model, the Decent Job derived from the first study was used, and the target model was derived from panel data of whole industries to understand the unique characteristics of logistics industry jobs and applied to the logistics industry model. This study found that in the logistics industry, developing the expertise of the logistics industry through "vocational training" compared to whole industries is an important factor rather than raising the "academic level" through the regular curriculum. This seems to reflect the characteristics of the logistics industry as specialized vocational training is required in the case of "railway transportation", "inland water and port transportation", and "air cargo transportation", which have a high proportion of decent job workers among the detailed logistics industries analyzed in this study. Therefore, developing job expertise through additional manpower training programs such as vocational training as well as academic fields learned through regular curriculum is a very important factor in engaging in "Decent Work" not only in the logistics industry but also in other industries.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.153-161
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• 1993

This study was conducted to compare the resistance and sensitivity of trees with 6 native species exposing to 4 different levels of $SO_2$gas(0.4, 0.7, 1.5 and 3.0 ppm) respectively. The results are summarized as follows : 1. Visible injuries appeared as spots in the region of intervein on the leaves for all the species and the color of the spots changed from light green and/or brown to light brown, dark brown, and/or redish brown. 2. The sensitivity of the species to $SO_2$ was high in the descending order of Zizyphus jujuba, Cataegus pinnatifida, Viburnum sargentii, Weigela subsessilis, Euonymus japonica, and Acer ginnala. 3. The resistance of the species to $SO_2$ was high in the descending order of Acer ginnala, Eunymus japonica Viburnum sargentii, Weigela subsessilis, Zizyphus jujuba, and Crataegus pinnatifida. 4. When the trees were exposed to $SO_2$gas, the contents of chlorophyll a, b, and a+b were consostently lower than those of control, and water soluble sulfur contents in the leaves were higher than those of control. 5. There was no significant correlation between stomatal resistance and the sensitivity(or resistance) of the trees exposed to $SO_2$ gas. 6. In this study, it was concluded that Acer ginnala was more suitable species than the others for landscape in air polluted area because it showed high resistance, low sensitivity, and low stromal resistance to $SO_2$gas exposure.