• Title/Summary/Keyword: 수인수

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Structural and Chemical Characterization of Aquatic Humic Substances in Advanced Water Treatment Processes (고도정수처리 공정에서 수질계 휴믹물질의 구조 및 화학적 특성분석)

  • Kim, Hyun-Chul;Yu, Myong-Jin
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.3
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    • pp.240-246
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    • 2005
  • Humic substances HS) from process waters at advanced water treatment plant consisted of GAC and Ozone/GAC processes were isolated and extracted by physicochemical fractionation methods to investigate their characteristics. They are characterized for their functionality, chemical composition, spectroscopic characteristics using FT-IR and $^1H$-NMR spectroscopy. Humic fraction gradually decreased from 36.3% to 24.2% from 0.45 to 0.30 mgC/L) through ozonation and carbon adsorption. The humic fraction was isolated into the phenolic and carboxylic groups using A-21 resin, and the concentration of phenolic groups gradually decreased from 38.4% to 23.5% (from 4.9 to $3.2\;{\mu}M/L$ as phenolic-OH) through ozonation and carbon adsorption. In the case of carboxylic groups, the concentration decreased from 61.6% to 43.3% (from 7.8 to $5.8\;{\mu}M/L$ as COOH) through the water treatment processes. On the other hand, concentrations of those roups decreased from 38.4% to 24.0% and 61.6% to 44.9% through carbon adsorption without ozonation, respectively. The structural changes of HS identified from FT-IR and $^1H$-NMR were consistent with the results from the isolation of functional groups in HS.

Development of the U-turn Accident Model at Signalized Intersections in Urban Areas by Logistic Regression Analysis (로지스틱 회귀분석에 의한 도시부 신호교차로 유턴 사고모형 개발)

  • Kang, Jong Ho;Kim, Kyung Whan;Kim, Seong Mun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.4
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    • pp.1279-1287
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    • 2014
  • The purpose of this study is to develop the U-turn accident model at signalized intersections in urban areas. The characteristics of the accidents which are associated with U-turn operation at 3 and 4-legged signalized intersections was analyzed and the U-turn accident model was developed by regression analysis in Changwon city. First, in order to analyze the effectiveness on traffic accidents by U-turn installation, the difference of mean of traffic accident number are measured between two groups which are composed by whether or not U-turn installation the groups by Mann-Whitney U test. The result of significance test showed that intergroup comparison on mean by accident types made difference except rear-end accident type and by accident locations exit section only showed difference in significance level at 4-legged intersections, so the accident number have more where the U-turn is permitted than not. Response measures about the number of accidents were classified by whether accidents occurred and accident model were constructed using binomial logistic regression analysis method. The developed models show that the variables of conflict traffic, number of opposing lane are adopted as independent variable for both intersections. The variables of longitudinal grade for 3-legged signalized intersection and number of crosswalk for 4-legged signalized intersection at which the U-turn is permitted is adopted as independent variable only. These study results suggest that U-turn would be permitted at the intersection where the number of opposing lane is more than 3.5 each, the longitudinal grade of opposing road is upward flow and there is need to establish the U-turn traffic sign at signalized intersections.

An Epidemiological Investigation on an Outbreak of Shigellosis during Travelling Cambodia and Vietnam among Korean Rural People, 2005 (2005년 농촌 주민들에서 캄보디아와 베트남 여행 중 발생한 세균성이질)

  • Lim, Hyun-Sul;Lee, Hwan-Seok
    • Journal of agricultural medicine and community health
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    • v.34 no.3
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    • pp.368-374
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    • 2009
  • Objectives: A group consisted of 32 Korean rural people had been travelled to Cambodia and Vietnam. During their travel for 7 days, first diarrheal case had occurred on 3rd day of travel and overall 8 people had diarrhea during travel. So we investigated the case for determination of the cause and route of infection. Methods: We interviewed all 32 people by visiting or telephone and took 23 stool samples from them, which are examined by Gyeungsangbuk-do Government Public Institute of Health & Environment in Korea. We interviewed travel agency for travel route and schedule. Results: The attack rate was 25.0% (8 cases) among 32 people. Of them, 3 cases were microbiologically confirmed to have the infection of Shigella flexneri (Serotype 3a). The result of this epidemiological investigation showed that the infection of shigellosis was happened in foreign countries. We assumed the water from Angkor-Watt was contaminated by S. flexneri. We could not able to test environmental specimens because of the infection is thought to be occurred in foreign countries. Conclusions: Most common infectious diseases from foreign countries are transmitted by water or food. Travellers to foreign countries must take caution for communicable diseases and must do report and get appropriate treatment when symptoms developed after travel.

Development of Techniques for Evaluating the Virus Removal Rate using Adenovirus (아데노바이러스를 이용한 바이러스 제거율 평가를 위한 기법 개발)

  • Cho, Yoonjung;Lim, Jaewon;Baek, Dawoon;Lee, Sang-Hoon;Lee, In-Soo;Lee, Hyeyoung;Park, Donghee;Jung, Dongju;Kim, Tae Ue
    • Journal of Korean Society of Water and Wastewater
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    • v.29 no.6
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    • pp.633-641
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    • 2015
  • Waterborne infectious disease is induced by several pathogenic microbes such as bacteria, viruses and protozoans, and the cases caused by viral infection is currently increasing. Water treatment process could reduce the number of virus in the water, but there were many difficulties to completely remove the virus particles from water. Therefore, the membrane separation technology which was reported to effectively remove pollutants from raw water has attracted increasing attention and demand. Since its efficiency has been introduced, demands for evaluation method toward the membrane filtration process are increasing. However, progression of the method development is slow due to the difficulties in cultivation of several waterborne viruses from animal models or cell culture system. To overcome the difficulties, we used adenovirus, one of the commonly isolated pathogenic waterborne viruses which can grow in cell culture system in vitro. The adenovirus used in this study was identified as human adenovirus C strain. The adenovirus was spiked in the raw water and passed through the microfiltration membrane produced by Econity, a Korean membrane company, and then the viral removal rate was evaluated by real-time PCR. In the results, the amount of virus in the filtered water was decreased approximately by 5 log scale. Because coagulant treatment has been known to reduce filtering function of the membrane by inducing fouling, we also investigated whether there was any interference of coagulant. In the results, we confirmed that coagulant treatment did not show significant interference on microfiltration membrane. In this study, we found that waterborne virus can be effectively removed by membrane filtration system. In particular, here we also suggest that real-time PCR method can rapidly, sensitively and quantitatively evaluate the removal rate of virus. These results may provide a standard method to qualifying membrane filtration processes.

Analysis of the Influence of Street Trees on Human Thermal Sensation in Summer (여름철 인간 열환경지수에 미치는 가로수의 영향 분석)

  • Jo, Sang-man;Hyun, Cheol-ji;Park, Soo-kuk
    • Journal of the Korean Institute of Landscape Architecture
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    • v.45 no.5
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    • pp.105-112
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    • 2017
  • In order to analyze the effect of street trees on human thermal sensation(thermal comfort) in summer, microclimatic data were measured and analyzed at sunny and shaded locations of two deciduous broadleaf and three broadleaf evergreen species of street trees. As a result, the mean differences by species in air temperature, relative humidity and wind speed were small: $0.2{\sim}1.5^{\circ}C$, 0.9~5.3% and $0.1{\sim}0.5 ms^{-1}$, respectively, but the mean difference in the mean radiant temperature was great, $27.1^{\circ}C$. In the results of physiological equivalent temperature(PET) and universal thermal climate index(UTCI), which are human thermal sensation(thermal comfort) indexes, the shaded locations by the trees showed mean reduction rates of 21.2~31.3% in the PET compared with the sunny location, which are equivalent to 1.5~2.5 levels of thermal perception. Also, 12.7~20.0% in the UTCI was reduced by the trees' shadows, which is equivalent to 1~1.5 levels of heat stress. In addition, although the broadleaf evergreen trees had 5% greater mean reduction in PET than that of the deciduous broadleaf trees, the Zelkova serrata that belonged to the deciduous broadleaf trees showed the equivalent thermal reduction effect as the broadleaf evergreen trees because of the high density of branches and leaves. Therefore, the mean radiant temperature and the density of the crown(branches and leaves) were the main influences in thermal modification by these street trees in summer.

Deterioration Diagnosis and Conservation Treatment of the Jincheon Sagongnimaaeyeoraeipsang (Stone Relief of Standing Buddha in Sagok-ri), Korea (진천 사곡리 마애여래입상의 훼손도 진단과 보존처리)

  • Kim, Sa-Dug;Lee, Myeong-Seong;Han, Byeong-Il;Lee, Jang-Jon;Song, Chi-Young
    • Journal of Conservation Science
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    • v.25 no.3
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    • pp.323-333
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    • 2009
  • The Jincheonsagongnimaaeyeoraeipsang is a great stone relief Buddha in Goryeo Dynasty, transmitting sculptural styles of the Silla Kingdom. The Buddha was carved on the biotite granite basement, and was undergone cleaning treatment in 2007. The basement rock was opened in plenty cracks bringing out structural instability. And the top of the basement rock was colonized by trees obstructing sunshine and raising humidity. As a result of failure analysis, the basement rock of the Buddha had a major possibility of wedge failure in the parts of the face, hands and cloths. Therefore, the cracks were filled up with epoxy resin L-50, and titanium bars and wire ropes were applied to bind cracked rock blocks. The surface of the crack filler was colored by granite and talc powder with inorganic pigment and L-30. The crack meters were installed on the stone relief Buddha to monitor further behavior, lastly.

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The Effects of Genetically Modified Crops on Soil Microbial Community (유전자변형 작물이 토양 미생물상에 미치는 영향)

  • Lee, Ki-Jong;Oh, Sung-Dug;Sohn, Soo-In;Ryu, Tae-Hun;Park, Jong-Sug;Lee, Jang-Yong;Cho, Hyun-Suk;Ahn, Byung-Ohg
    • Korean Journal of Environmental Agriculture
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    • v.31 no.2
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    • pp.192-199
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    • 2012
  • BACKGROUND: Genetically modified (GM) crops must receive relevant regulator's authorization before they can be sold as seed or used food, feed and processing. Before approving any GM crop, the relevant government ministries are required to examine environmental risk assessment to make scientifically sound and socially acceptable decisions. But one of the least studied and understood areas in the environmental risk assessment of GM crops are their impact on soil microbial community. METHODS AND RESULTS: Recently, advanced methods have been developed to characterize the soil microbial community in various environments. In this study, the culture-dependent and culture-independent technical approaches for profiling soil microbial communities are summarized and their applicability to assess GM crops are discussed. CONCLUSION(S): We concluded that the effect of GM crops on soil microbial community need to be assessed on a case by case basis. The combination of culture-dependent and culture-independent method was necessary for reliable and detailed assessment of effect of GM crops on soil microbial community.

Evaluation and Application of Algae Online Analyzer for Alarming Algal Bloom and Water Quality Management of Korean Reservoirs (조류발생 경보 및 호수 수질관리를 위한 엽록소 자동측정기의 적용 및 타당성 연구)

  • Hwang, Su-Ok;Han, Myung-Soo;Kim, Baik-Ho
    • Korean Journal of Ecology and Environment
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    • v.39 no.2 s.116
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    • pp.257-264
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    • 2006
  • In order to evaluate the application of Algae Online Analyzer (AOA), an instrument of automatic measurement of chlorophyll a concentration, was tested and compared with the acetone extraction method on the basis of microscopic counting of phytoplankton in field water (Paltang Reservoir). We simultaneously conducted AOA operation and extraction method with the same water sample, to compare both results of chlorophyll a measurement. Phytoplankton were enumerated by inverted microscope with the Sedgwick-Rafter chamber, and classified into the genus or species. According to the AOA measurement, the diatom most (83.6%) strongly contributed to the total chlorophyll a concentration, followed by chlorophyceae> cyanophyceae>cryptophyceae. Overall, the results of both AOA and extraction method showed a similar trend and significant correlation (r=0.87, n=302, p<0.001), however, there were some differences according to the season and species. In particular, the relationship between AOA Chl-a density of the diatom (r=0.73, p=0.010) and cyrptophyceae (.=0.83, p=0.00154) were siginificant, while chlorophyceae (r= -0.13) and cyanophyceae (r= -0.16) showed no clear relationship during the study period. Although we can not fully understand why there was difference between both mothods, AOA application for alarming algal bloom and water quality management during the algal bloom appears to be very relevant. However, the further study or technical upgrade of AOA measurement is required, especially in the case of low density of phytoplankton or species-specific measurement.

Bayesian ordinal probit semiparametric regression models: KNHANES 2016 data analysis of the relationship between smoking behavior and coffee intake (베이지안 순서형 프로빗 준모수 회귀 모형 : 국민건강영양조사 2016 자료를 통한 흡연양태와 커피섭취 간의 관계 분석)

  • Lee, Dasom;Lee, Eunji;Jo, Seogil;Choi, Taeryeon
    • The Korean Journal of Applied Statistics
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    • v.33 no.1
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    • pp.25-46
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    • 2020
  • This paper presents ordinal probit semiparametric regression models using Bayesian Spectral Analysis Regression (BSAR) method. Ordinal probit regression is a way of modeling ordinal responses - usually more than two categories - by connecting the probability of falling into each category explained by a combination of available covariates using a probit (an inverse function of normal cumulative distribution function) link. The Bayesian probit model facilitates posterior sampling by bringing a latent variable following normal distribution, therefore, the responses are categorized by the cut-off points according to values of latent variables. In this paper, we extend the latent variable approach to a semiparametric model for the Bayesian ordinal probit regression with nonparametric functions using a spectral representation of Gaussian processes based BSAR method. The latent variable is decomposed into a parametric component and a nonparametric component with or without a shape constraint for modeling ordinal responses and predicting outcomes more flexibly. We illustrate the proposed methods with simulation studies in comparison with existing methods and real data analysis applied to a Korean National Health and Nutrition Examination Survey (KNHANES) 2016 for investigating nonparametric relationship between smoking behavior and coffee intake.

Quality Characteristics of Brown Sauce Made with Freeze-dried Salicornia herbacea L. Powder (함초를 이용한 브라운소스에 관한 품질특성)

  • Kim, Ja-Kyoung;Yoo, Seung-Seok
    • Culinary science and hospitality research
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    • v.18 no.5
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    • pp.243-255
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    • 2012
  • This research has been conducted to develop the best recipe for brown sauce containing freeze-dried Salicornia powder. For this purpose, we made brown sauces with different contents of freeze-dried Salicornia powder and performed physico-chemical characteristic and sensory test. The highest salinity of freeze-dried Salicornia powder was 0.15% when 1% freeze-dried Salicornia powder was added to distilled water, SP1. The highest brightness of brown sauce was achieved with 1.2% freeze-dried Salicornia powder and was 45.29 with BSP12. More powder led to significant increases of the samples(p<0.001) in salinity and brightness. DPPH radical scavenging increased with greater freeze-dried Salicornia powder. Taste was highest at 6.36 with 0.6% powder and there was no significant difference compared to BSP6 and BSP9. Based on these findings, it was concluded that the brown sauce with Salicornia has antioxidative characteristics and the best salinity is achieved with 0.6% freeze-dried Salicornia powder. Salicornia had enough salinity to substitute salt to a certain degree and improved the quality of brown sauce in terms of the sensory test.

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