• Title/Summary/Keyword: 학과 만족도

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Surfactant Enhanced In-Situ Soil Flushing Pilot Test for the Soil and Groundwater Remediation in an Oil Contaminated Site (계면활성제 원위치 토양 세정법을 이용한 유류 오염 지역 토양.지하수 정화 실증 시험)

  • 이민희;정상용;최상일;강동환;김민철
    • Journal of Soil and Groundwater Environment
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    • v.7 no.4
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    • pp.77-86
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    • 2002
  • Surfactant enhanced in-situ soil flushing was performed to remediate the soil and groundwater at an oil contaminated site, where had been used as a military vehicle repair area for 40 years. A section from the contaminated site (4.5 m $\times$ 4.5 m $\times$ 6.0 m) was selected for the research, which was composed of heterogeneous sandy and silt-sandy soils with average $K_d$ of 2.0$\times$$10^{-4}$cm/sec. Two percent of sorbitan monooleate (POE 20) and 0.07% of iso-prophyl alcohol were mixed for the surfactant solution and 3 pore volumes of surfactant solution were injected to remove oil from the contaminated section. Four injection wells and two extraction wells were built in the section to flush surfactant solution. Water samples taken from extraction wells and the storage tank were analyzed on a gas-chromatography (GC) for TPH concentration in the effluent with different time. Five pore volumes of solution were extracted while TPH concentration in soil and groundwater at the section were below the Waste Water Discharge Limit (WWDL). The effluent TPH concentration from wells with only water flushing was below 10 ppm. However, the effluent concentration using surfactant solution flushing increased to 1751 ppm, which was more than 170 times compared with the concentration with only water flushing. Total 18.5 kg of oil (TPH) was removed from the soil and groundwater at the section. The concentration of heavy metals in the effluent solution also increased with the increase of TPH concentration, suggesting that the surfactant enhanced in-situ flushing be available to remove not only oil but heavy metals from contaminated sites. The removal efficiency of surfactant enhanced in-situ flushing was investigated at the real contaminated site in Korea. Results suggest that in-situ soil flushing could be a successful process to remediate contaminated sites distributed in Korea.

Treatment of Contaminated Sediment for Water Quality Improvement of Small-scale Reservoir (소하천형 호수의 수질개선을 위한 퇴적저니 처리방안 연구)

  • 배우근;이창수;정진욱;최동호
    • Journal of Soil and Groundwater Environment
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    • v.7 no.4
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    • pp.31-39
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    • 2002
  • Pollutants from industry, mining, agriculture, and other sources have contaminated sediments in many surface water bodies. Sediment contamination poses a severe threat to human health and environment because many toxic contaminants that are barely detectable in the water column can accumulate in sediments at much higher levels. The purpose of this study was to make optimal treatment and disposal plan o( sediment for water quality improvement in small-scale resevoir based on an evaluation of degree of contamination. The degree of contamination were investigated for 23 samples of 9 site at different depth of sediment in small-scale J river. Results for analysis of contaminated sediments were observed that copper concentration of 4 samples were higher than the regulation of hazardous waste (3 mg/L) and that of all samples were exceeded soil pollution warning levels for agricultural areas. Lead and mercury concentration of all samples were detected below both regulations. Necessary of sediment dredge was evaluated for organic matter and nutrient through standard levels of Paldang lake and the lower Han river in Korea and Tokyo bay and Yokohama bay in Japan. The degree of contamination for organic matter and nutrient was not serious. Compared standard levels of Japan, America, and Canada for heavy metal, contaminated sediment was concluded as lowest effect level or limit of tolerance level because standard levels of America and Canada was established worst effect of benthic organisms. The optimal treatment method of sediment contained heavy metal was cement-based solidification/stabilization to prevent heavy metal leaching.

Bacterial growth and carbon-to-phosphorus consumption in drinking water with different carbon and phosphorus levels (수돗물의 탄소와 인 농도에 따른 세균의 생장과 C/P 소모율)

  • Choi, Sung-Chan;Park, e-Keun;Kim, Yeong-Kwan
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.6
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    • pp.689-701
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    • 2013
  • Bacterial growth and corresponding consumption of carbon and phosphorus were examined in which tap water samples containing a very low concentration of free chlorine were supplemented with organic carbon and/or phosphorus. The experiments were performed in a fed-batch mode under a controlled temperature of $20^{\circ}C$. In the phosphorus alone-added water, there was no significant increase in bacterial numbers measured as heterotrophic plate count (HPC) in the bulk water. However, bacterial growth was stimulated by the addition of carbon (e.g., bulk HPC levels increased to $10^3CFU/mL$) and further stimulated by the combined addition of carbon and phosphorus (e.g., bulk HPC to $10^5CFU/mL$). The same effects were observed in biofilm HPC and biomass formed on polyethylene (PE) slide surfaces. In the water where organic carbon and phosphorus were added together, the highest biofilm HPC and biomass (measured as extracellular polymeric substance components) densities were observed which were $7.6{\times}10^5CFU/cm^2$ and $5.3{\mu}g/cm^2$, respectively. In addition to the bacterial growth, additions of organic carbon and/or phosphorus resulted in different bacterial carbon-to-phosphorus (C/P) consumption ratios. Compared to a typical bacterial C/P consumption ratio of 100:1, a higher C/P ratio (590:1) occurred in the carbon alone-added water, while a lower ratio (40:1) in phosphorus alone-added water. Comparative value (80:1) of C/P ratio was also observed in the water where organic carbon and phosphorus were added together. At the given experimental conditions, bacterial growth was deemed to be more sensitive to microbially available organic carbon than phosphorus. The effect of phosphorus addition, which resulted in a lower C/P consumption ratio, seemed to be tightly associated with the presence of microbially available organic carbon. These results suggested that the control of extrinsic carbon influx seemed to be more important to minimize bacterial regrowth in drinking water system, since even low content of phosphorus naturally occurring in drinking water was enough to allow a bacterial growth.

A Study on Leaching Characteristics of $Cr^{6+}$ in Cement Grout Materials (시멘트 그라우트재에서 $Cr^{6+}$용출특성에 관한 연구)

  • 김동우;이재영;천병식
    • Journal of Soil and Groundwater Environment
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    • v.8 no.2
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    • pp.62-69
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    • 2003
  • The aim of research is the evaluation of the $Cr^{6+}$ emission features of the liquid injection through emission experiments in varying conditions, based on a field-mixing ratio. The results showed that the content of $Cr^{6+}$ content in cement measured had an Ordinary Potland Cement (OPC) of 25.3 mg/kg, which constitute the largest portion among the other materials. Likewise, the emission experiment of homo-gel and sand-gel generally satisfied the standard of KSLT (Korea Standard Leaching Test) in waste of 1.5 mg/L, but in case of the standard of KSLT in soil the emission of OPC $Cr^{6+}$ of 4.85 mg/kg. These conditions is a little exceeded the criteria in the ‘Ga’ area in terms of Korea Soil Environmental Preservation Law. In addition, results generated by the mock-up injection facilities revealed that $Cr^{6+}$ emission increased as Water/Cement and injection pressure increased. At injection pressure higher than 4 kg/㎤, $Cr^{6+}$ emission exceeded the water preservation standard of 0.5 mg/L. Similarly, a pattern experiment of C $r^{6+}$ emission according to pH was conducted, in order to evaluate the $Cr^{6+}$ emission features of grout materials in leachate below pH 5 such as pH 4 acid rain or landfill. Results show that $Cr^{6+}$ emission dramatically increased in high acidic or basic state. It indicates that $Cr^{6+}$ emission will probably increase in an environment where grout materials are injected. On the other hand, concentration of leachate was determined in areas where grout materials are used. The results show that the concentration of emission in an ultra purity condition does not manifest intensity, and is affected in the OPC>MC>SC order. It means that the pollutants or $Cr^{6+}$ emission increases with decreasing concentration. As such, $Cr^{6+}$ emission will probably exceed the countermeasure criteria according to the types of gout materials. Similarly, high pressure or injection will cause increased $Cr^{6+}$ emission. Therefore, the selection of materials or mixing ratio should be considered in general as well as according to specific industries, based on the strength and pH of $Cr^{6+}$ emission.

A Review on the Chemistry of Soil Organic Matter - Progress in the Study on the Chemical Structure of Humic Substances - (토양(土壤) 유기물(有機物)의 생성(生成)과 성상(性狀) "부식물(腐植物)의 화학구조(化學構造) 연구(硏究)의 진전(進展)에 대하여")

  • Lim, Sun-Uk
    • Korean Journal of Soil Science and Fertilizer
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    • v.11 no.3
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    • pp.127-144
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    • 1979
  • Recent trend in the studies on the forming processes, chemical characteristics and chemical structure of humic substances with some discussions are reviewed and some arguments for the elucidation of the chemical structure of humic substances are summarized.

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Effect of Slurry Composting Bio-filtration (SCB) by Subsurface Drip Fertigation on Cucumber (Cucumis sativus L.) Yield and Soil Nitrogen Distribution in Greenhouse

  • Lim, Tae-Jun;Park, Jin-Myeon;Noh, Jae-Seung;Lee, Seong-Eun;Kim, Ki-In
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.4
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    • pp.253-259
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    • 2013
  • The use of subsurface drip fertigation using slurry composting bio-filtration (SCB) as nitrogen (N) fertilizer source can be beneficial to improve fertilizer management decision. The objective of this study was to evaluate effects of SCB liquid fertilizer by subsurface drip fertigation on cucumber (Cucumis sativus L.) yield and soil nitrogen (N) distribution under greenhouse condition. Cucumber in greenhouse was transplanted on April $4^{th}$ and Aug $31^{st}$ in 2012. N sources were SCB and urea. Four N treatments with 3 replications consisted of control (No N fertilizer), SCB 0.5N + Urea 0.5N (50:50 split application), SCB 1.0N, Urea 1.0N. 100% of N recommendation rate from soil testing was denoted as 1.0N. The subsurface drip line and a tensiometer were installed at 30 cm soil depth. An irrigation was automatically started when the tensiometer reading was -15 kPa. The growth of cucumber at 85 days after transplanting was 5% higher in all N treatment than control. Semi-forcing culture produced more fruit yield than retarding culture. Fruit yields were 62.2, 76.3, 76.4, and 75.1 Mg $ha^{-1}$ for control, SCB 1.0N, Urea 1.0N, and SCB 0.5N + Urea 0.5N, respectively. Although fruit yields were similar under SCB 1.0N, Urea 1.0N, and SCB 0.5N + Urea 0.5N, 176 kg K $ha^{-1}$ can be over applied if cucumber is grown twice a year under SCB 1.0N that may result in K accumulation in soil. N uptake was 172, 209, 213, 207 kg $ha^{-1}$ for control, SCB 1.0N, Urea 1.0N, and SCB 0.5N + Urea 0.5N, respectively. N use efficiency was the highest (37%) at SCB 0.5N + Urea 0.5N under semi-forcing culture. Nitrate-N concentration in soil for all N treatments except control in semi-forcing culture was the highest between 15 and 30 cm soil depth at the 85 days after transplanting and between 0 and 15 cm soil depth after cucumber harvest. These results suggested that SCB 0.5N + Urea 0.5N can be used as an alternative N management for cucumber production in greenhouse if K accumulation is concerned.

Wheel Balance Cancer Therapy in the Treatment of Metastatic Gastric Carcinoma : A Retrospective Analysis of 62 Patients (수레바퀴 암 치료법을 시행받은 진행성 위암환자 62명에 대한 후향적 코호트 분석)

  • Park, Jeong-Seok;Yoo, Hwa-Seung;Lee, Yeon-Weol;Cho, Jung-Hyo;Son, Chang-Gue;Cho, Chong-Kwan
    • The Journal of Internal Korean Medicine
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    • v.28 no.3
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    • pp.531-543
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    • 2007
  • Backgrounds : Gastric cancer is one of the most frequent causes of cancer-related deaths worldwide. Gastric cancer patients frequently exhibit distant metastasis at the time of diagnosis and at present, there is no standard regimen after operation or chemotherapy to prevent metastasis and recurrences. Aims : The objective of the study was to compare the overall survival and disease free survival in patients treated with wheel balance therapy (WBT) with patients treated with WBT alone or the combination of WBT and conventional therapy and see if there were any significant improvements in survival between the two groups. Setting & Design : East-West Cancer Center at Daejeon University: retrospective study. Materials & Methods : We retrospectively analyzed 62 patients with stage III (40 patients) and stage IV (22 patients) gastric cancer who have received operation or chemotherapy 2 months prior to beginning WBT. The patients followed the WBT protocol which includes herbal medicine such as PSM capsules, OnePlus syrup, or HAD capsules which prevent metastasis and recurrences. Overall survival and disease free survival were analyzed and the patients were treated for 89.55 weeks and 49.27 weeks (median value) for stages III and IV, respectively. Statistical analysis used : Overall survival and disease free survival were estimated using the Kaplan-Meier method and the WBT and combination treatment arms were compared using the log rank test. Results : For stage III, the 3 year overall survival was 78.5% and disease free survival was 78.3%. Metastasis and recurrence occurred in 13 of 40 patients (32.5%). For stage IV, the 2 year overall survival was 18.2% and disease free survival was also 18.2%. Metastasis and recurrence occurred in 19 of 22 patients (86.4%). No significant difference was found statistically between the WBT alone and combination treatment arms though the combination regimen showed superiority (overall survival p=0.5093, disease free survival p=0.5175). Conclusions : WBT yielded satisfactory results in prolonging survival and preventing metastasis and recurrence in gastric cancer patients. The major treatment unit of WBT is composed of herbal medications (HAD, PSM capsules, OnePlus syrup) and a randomized, prospective study should be carried out using only this treatment unit in the future.

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On Method for LBS Multi-media Services using GML 3.0 (GML 3.0을 이용한 LBS 멀티미디어 서비스에 관한 연구)

  • Jung, Kee-Joong;Lee, Jun-Woo;Kim, Nam-Gyun;Hong, Seong-Hak;Choi, Beyung-Nam
    • 한국공간정보시스템학회:학술대회논문집
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    • 2004.12a
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    • pp.169-181
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    • 2004
  • SK Telecom has already constructed GIMS system as the base common framework of LBS/GIS service system based on OGC(OpenGIS Consortium)'s international standard for the first mobile vector map service in 2002, But as service content appears more complex, renovation has been needed to satisfy multi-purpose, multi-function and maximum efficiency as requirements have been increased. This research is for preparation ion of GML3-based platform to upgrade service from GML2 based GIMS system. And with this, it will be possible for variety of application services to provide location and geographic data easily and freely. In GML 3.0, it has been selected animation, event handling, resource for style mapping, topology specification for 3D and telematics services for mobile LBS multimedia service. And the schema and transfer protocol has been developed and organized to optimize data transfer to MS(Mobile Stat ion) Upgrade to GML 3.0-based GIMS system has provided innovative framework in the view of not only construction but also service which has been implemented and applied to previous research and system. Also GIMS channel interface has been implemented to simplify access to GIMS system, and service component of GIMS internals, WFS and WMS, has gotten enhanded and expanded function.

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A Survey on Food Purchasing Behavior among Middle School Students (중학생의 식품 구매 행동 실태)

  • Oh, Mi-Ran;Lee, Hye-Suk;Na, Hyeon-Ju;Kim, Young-Nam
    • Journal of Korean Home Economics Education Association
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    • v.18 no.4 s.42
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    • pp.173-192
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    • 2006
  • The purpose of this study was to provide basic data for developing nutrition education program focusing on the health-oriented food choice and purchase which affect the adolescents' health. The data was collected by means of questionnaire from the total of 273 students who were living in cities and myun district and final 253 questionnaires were analyzed by using the SPSS/WIN 10.0 program. The results are summarized as follows. First, the major source of information on food was mass media, especially advertisement and students spent $20{\sim}30%$ of allowance on food purchase. The students purchased cookies or ice cream mainly, once every 2-3 days at the store near house, after school, for appeasing hunger or thirst. The influence of gender, mother's education level, economic status of family, the amount of allowance, the period of receiving allowance, the details of allowance recording, school location on food purchasing behavior were significant(p<.05). Second, the price and taste were the most important factors when the students purchase food. Nutrition and food sanitation/safety were considered less important by the students. The factors considered when the students purchase food were significantly different between Sender, father and mother's education level, and the amount of allowance(p<.05). Third, middle school students' food purchase behavior were influenced by advertizement, friends, parents. The influence of advertisement, friends, parents when the students purchase food were significantly different between gender, mother's career, economic status of family, and the amount of allowance(p.<05). From tile result of this study, the middle school students consider price and taste more than the other factors related nutrition and health in purchasing foods. Therefore, it will be necessary to develope and enforce nutrition education program focusing on how to choose and purchase safe, nutritious, delicious and cheap foot for adolescents.

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A Survey on Practices and Attitude toward Wedding Food among Housewives in Busan and Kyungnam Area (부산.경남지역 주부들의 혼례음식 관행과 태도에 관한 조사)

  • Kim, Kyong-Myo;Kim, Kyung-Ja;Shin, Ae-Sook
    • Journal of the Korean Society of Food Culture
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    • v.17 no.3
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    • pp.240-251
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    • 2002
  • This study is to describe practices of and attitude toward traditional wedding food and the attitude of housewives toward the traditional wedding food in Busan metropolitan and Kyungnam province area. Data were analyzed from the convenient sample of 525 housewives collected from September 20 to September 28, 2001. As for the necessity of traditional wedding food, the most popular food was ebagee food, pebaek food, yedan food in order. Of the various kinds of traditional wedding food, table setting for parent-in-law was chosen as the most popular one. Sociodemographic characteristics such as education level and age were statistically associated with perception of traditional wedding food being necessary as a ritual thing. The respondents preferred rice cakes as wedding food to fishes, fruits, traditional sweets and skewered slices of seasoned meats. More than half of the respondents think current practices of wedding food is prodigal and has to be done in thrifty manner. As a ritual practices of wedding food were to be readjusted to the change of social custom depending on the degree of modernization. More than half (52.1%) of the housewives expected traditional wedding food should fade away. A conclusion was that it is necessary to develop modernized wedding food reflecting traditional wedding customs with economic costs.