• Geomechanics and Engineering
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• 제28권2호
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• pp.145-155
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• 2022

Safety is a most important parameters in underground railway transportation; Also stability of underground tunnel is very important in tunneling engineering. Design of a reliable support system requires an evaluation of both ground demand and support capacity. Iran's traditional railway tunnels are mainly supported with masonry structures or unsupported in high quality rock masses. A decrease in rock mass quality due to changes in groundwater regime creep and fatigue in rock and similar phenomena causes tunnel safety to decrease during time. The case study is an old tunnel in Iran, called "Keshvar"; it is more than 50 years old railway organization. In operating this Tunnel, until the several problems came up based on stability and leaking water. The goal of study is evaluation of the various reinforcement systems for supporting of the tunnel. The optimal selection of the reinforcement system is examined using TOPSIS Fuzzy method in light of the looming and available uncertainties. Several factors such as; the tunnel span, maintenance, drainage, sealing, ventilation, cost and safety were based to choose the method and system of designing. Therefore, by identifying these parameters, an optimal reinforcement system was selected and introduced. Based on optimization system for analysis, it is revealed that the systematic rock bolts and shotcrete protection had a most appropriate result for these kind of tunnel in Iran.

• 한국습지학회지
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• 제24권1호
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• pp.44-51
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• 2022

본 연구에서는 TOPSIS(Techniques for Order Performance by Similarity to Ieal Solution)을 이용하여 낙동강수계 34개 지천에서의 수질측정망 설치 지점에 대하여 평가하였다. 낙동강수계에서는 지난 2011년부터 195개 지천에서 수질 및 유량을 측정하고 있다. 특히, 34개 중점관리지점은 오염원이 많고 수질이 불량한 지역으로서 지속적인 수질이 관리가 필요하다. 관리가 필요한 지점 선정을 위해 평가항목은 10개 지표를 선정하였으며 선정된 지표를 표준화하고, 엔트로피 방법(Entropy Method)을 이용하여 가중치를 부여하였다. 가중치 산정결과, 인근 측정망 유무가 가장 크고 평균 수질과 산업단지 유무도 높은 가중치를 얻었다. 평가결과, 상위 지점은 인근 측정망이 없고 산업단지와 폐수처리시설이 있고 평균 수질이 타 지점보다 높은 지점이다. 평가된 자료는 향후 낙동강수계에서의 신규 수질측정망 설정 및 지속적인 지류에서의 수질 관리를 위해 필요한 연구 결과로 판단된다.

• 한국환경과학회지
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• 제22권4호
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• pp.453-461
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• 2013

This study, changes in raw water quality is to indicate on the efficiency of ozone treatment of each pollutant as compared to derive the appropriate operating measures. The appropriate selection for injection rate of pre-ozone and did not inject pre-ozone assess changes in the water. When good water quality, you not injected of pre-ozone to evaluate the economic efficiency of electricity and put the most cost-effective ozone concentration were evaluated. Evaluation remove organic matter and chlorophyll-a concentration level in experiments with each factor of the water DOC> 2.5 mg/L, THMFP> 70 ${\mu}g/L$, Chl-a> 30 $mg/m^3$or less constant process, if you do not need to put pre-ozone showed little impact. It also does not put you in pre-ozone appropriate produce enough power rate savings was calculated as approximately 90 million won. Ability to remove organic materials and the ability to produce disinfection byproducts, and cost-effective decisions by considering the concentration of injection if pre-ozone 1 mg/L was investigated by the appropriate concentration of ozone injection.

• 한국환경복원기술학회지
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• 제16권4호
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• pp.99-114
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• 2013

In this study, constructability of ecologocal stream restoration process was evaluated and improved approaches for habitat were suggested. The study site is Gucheon River in Geoje city where conducted ecologocal restoration work within maintaining its flood control function. Application of ecological design factors and constructability in the process from planning to construction was analyzed and its results are as follows: In the process of planning and designing, it was focused more on the naturality of Gucheon River rather than the human convinience and ecological design factors were applied within the ecological capacity of the site. First, the indexes for constructability evaluation is selected. It was classified into three major categories as construction quality, design quality and construction administration system. Each index has details, so there are twenty sub indexes for contractibility evaluation. Second, the evaluation results shows that the index most in need of improvement was plumbing construction, followed by Stone construction and pavement construction. design concept was evaluated as appropriate in entire categories. Finally it is suggested that it can be improved in both process of design to enhance the technology and process of construction to enhance the quality management. The constructability of ecological stream needs adaptive management and it must be discussed with its designing which is at the stage before construction. Also it needs discussion with its designer constantly and feed-back process.

• 한국환경보건학회지
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• 제45권1호
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• pp.42-53
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• 2019

Objectives: The Yongpung reservoir in Korea is a crucial facility that supplies water to farms in its surrounding $2km^2$ area. However, its water quality is not suited to the needs of current residents who wish for the availability of environmentally friendly agricultural products and desire to use the waterfront area. The aim of this research was to evaluate the reservoir's fish and benthic macroinvertebrate distributions and determine its water quality and the heavy metal content in its sediment. This basic data can be used to establish environmentally protective plans for the Yongpung reservoir. Methods: Six sites were selected for analysis in this investigation. Three points (YP-1, YP-2, and YP-3) were evaluated for water quality and metal content in sediments; they were located upstream, midstream, and downstream of the reservoir. Samplings of the fish and benthic macroinvertebrate populations were performed at three other sites: St. 1, St. 2, and St. 3. Results: Based on chemical oxygen demand (COD) and total nitrogen (T-N) data, the quality of the Yongpung reservoir water corresponds to Class VI (very poor) according to Korea's lake environmental standards. The lead levels measured in the sediment at the midstream and downstream points of the reservoir were 76.7 and 72.7 mg/kg, respectively, while 8 orders, 15 families, and 16 species of benthic macroinvertebrates were identified in the reservoir. The ecological score of the benthic macroinvertebrate community (ESB) was between 8 and 23, denoting poor to very poor environmental conditions. Further, 4 families and 7 species of fish were identified in the reservoir, with Cyprinidae accounting for 94.3% of all observed freshwater fish. Conclusion: Based on these findings, we conclude that management plans, including the removal of lead from the sediment, are necessary to improve the quality of the agricultural water in this reservoir. The T. japonica, which cover almost 30% of the water area, must also be removed.

• 한국환경과학회지
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• 제22권2호
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• pp.205-213
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• 2013

This is made of domestic and foreign coal activated carbon of five species, physicochemical adsorption efficient about sterilize products and micro harmful substances and is a result of the economic evaluation. The most well-developed micropores bed volume 123,409 of AC-1 activate carbon appeared to be the best next AC-2, AC-3, AC-4, AC-5 followed by activated carbon was investigated. PFOA and PFOS in the BV 96,000 when evaluating foreign types of adsorption activated carbon adsorption capacity was greater when more than PFOA, PFOS showed that the adsorption well. The economic evaluation of activated carbon usage in chloroform (CUR) was most excellent as a AC-1 4.3 g/day, the next AC-2, AC-3, AC-4, AC-5 there are two types of foreign economic order appears to have appeared, but the current domestic market when applying the price AC-1, AC-3, AC-2, AC-4, AC-5 order was investigated.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권1호
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• pp.22-32
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• 2012

This study suggests a method to grade groundwater quality quantitatively using statistical approaches for evaluating the quality of groundwater in wells included in the Groundwater Quality Monitoring Network (GQMN). The proposed analysis method is applied to GQMN data from 2001 to 2008 for nitrate nitrogen, chloride, trichloroethylene, potential of hydrogen (pH), and electrical conductivity. The analysis results are obtained as groundwater quality grades of the groundwater representing each of the monitoring stations. The degree of groundwater contamination is analysed for water quality parameters, district, and usage. The results show that the degree of groundwater contamination is relatively high by nitrate nitrogen, bacteria and electrical conductivity and at Seoul, Incheon, Gwangju, Gyeonggido and Jeollado. The degree of contamination by nitrate nitrogen and trichloroethylene is especially high when the groundwater is used for agricultural and industrial water, respectively. It is evaluated that potable groudnwater in GQMN is significantly vulnerable to nitrate nitrogen and bacteria contamination.

• 한국환경과학회지
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• 제24권1호
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• pp.133-150
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• 2015

Wind profiler provides vertical profiles of three-dimensional wind vectors with high spatiotemporal resolution. The wind vectors is useful to analyze severe weather phenomena and to validate the various products from numerical weather prediction model. However, the wind measurements are not immune to ground clutter, bird, insect, and aircraft. Therefore, quality of wind vectors from wind profiler must be quantitatively evaluated prior to its application. In this study, wind vectors from UHF wind profiler at Ganwon Regional Meteorological Administration was quantitatively evaluated using 27 radiosonde measurements that were launched every two or three hours according to rainfall intensity during Intensive Observation Period (IOP) from June to July 2013. In comparison between two measurements, wind vectors from wind profiler was relatively underestimated. In addition, the accuracy and quality of wind vectors from wind profiler decrease with increasing beam height. The accuracy and quality of the wind vectors for rainy periods during IOP were higher than for the clear-air measurements. The moderate rainfall intensity lead to multi-peaks in Doppler spectrum. It results in overestimation of vertical air motion, whereas wind vectors from wind profilers shows good agreement with those from radiosonde measurements for light rainfall intensity.

• Membrane and Water Treatment
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• 제10권5호
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• pp.339-352
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• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• 한국환경복원기술학회지
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• 제14권5호
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• pp.81-101
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• 2011

This study was conducted to understand the environmental and ecological function of habitat through evaluation of water environment, soil environment, vegetation characteristics, macro-invertebrate characteristics, and visual habits environment evaluation (SVAP) in Hongdong stream located in Hongseong-Gun, Chungnam Province, and hereafter to utilize the results for the habits reconstruction and improvement project. As the results of water quality analysis, BOD, COD, T-P was almost below the standard quality from upper stream to down stream. The construction of small reservoir, wetland and water purification facility, and the management of non-point pollution are proposed to improve these problems. The soil texture was sandy soil, which is unfitted with vegetation development. The construction of shallows and bogs, and induction of soil sedimentation and biotope formation are proposed to improve these problems. In the plant flora, total 90 kinds were observed with 81 species and nine varieties in total 36 families and 85 genera, and the naturalization rate was higher at down area than upper area. As the results of macro-invertebrate fauna survey, total 26 species and 297 individuals in 20 families and 22 genera were collected. Peltodytes sinensis, Chironomidae sp., and Culicidae sp., which are observed at polluted environment, were collected as dominant species. An appropriate vegetation management party idea is necessary, and it is done an idea in consideration of the soil and a physical characteristic. Visual habits environment evaluation (SVAP) result was mostly determined with below normal (Fair) grade. Pollution source interception, purification pond establishment, and various bog establishment are proposed to improve these problems. With the above results, the ecological environment was determined with bad condition, and the improvement of biotope was urgently needed through sustainable monitoring and management of streams habitat in rural area.