• 한국지반환경공학회 논문집
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• 제11권12호
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• pp.13-18
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• 2010

본 연구는 최근 개발된 실리카졸 그라우팅재의 환경영향성 및 내구성을 규명한 것으로써 연구에 사용된 그라우트재는 3차원 겔 형성재인 실리카졸 그라우팅제와 규산나트륨 그라우팅제에 대한 공학적 특성을 비교하기 위하여 전자현미경 촬영, 내화학성시험, 용탈시험, 투수시험 등을 통해 친환경성과 내구성을 규명하고자 하였다. 전자현미경 촬영 결과 실리카졸 그라우팅제의 표면 및 내부조직이 규산나트륨보다 치밀함을 확인할 수 있었다. 용탈시험 결과 용탈되는 원소의 총량도 극히 작아 친환경적인 재료임을 입증되어 지반주입재로써 적용성을 확인하였다. 투수시험 결과 실리카졸이 차수성면에서 현장에 적용하는데 무리가 없다고 판단되어 차수성을 요구하는 현장에 적용이 가능하다고 판단된다.

• 환경영향평가
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• 제9권1호
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• pp.61-74
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• 2000

This study compares the results of environmental impact assessment with the results of post-environmental investigation, using the case of Taean thermal power plant construction. The atmospheric and water qualities were not greatly changed before and after the construction of the power plant. However, the site of the highest concentration predicted by the atmospheric quality modeling in environmental impact assessment was different from that after operation of 4 power plants. There was also a difference in the diffusion range of thermal discharge water between the measured result(1km) and the predicted value(1.5km) with the model. Thus, environmental impact evaluation should be based on long-term (more than a year) environmental monitoring data. For the modeling of atmospheric quality and numerical thermal discharge water diffusion, appropriate models for each plant should be selected and the numerical modeling should be accompanied by computer simulation, wind tunnel test, etc. Moreover, environmental evaluation should focus more on the degree of impact on surroundings than the prediction of changes in surroundings caused by operation of plants.

• 환경영향평가
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• 제6권1호
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• pp.111-119
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• 1997

This study was carried out to suggest the best statistical test which may be used to quantify the change of water quality between two groups. Traditional t-test may not be used in cases where the normality of underlying population distribution is not assured. Three non-parametric tests which are based on the relative order of the measurements, were studied to find out the applicability in water quality data analysis. The sign test is based on the sign of the deviation of the measurement from the median value, and the binomial distribution table is used. The signed rank test utilizes not only the sign but also the magnitude of the deviation. The Wilcoxon rank-sum test which is basically same as Mann-Whitney test, tests the mean difference between two independent samples which may have missing data. Among the three non-parametric tests studied, the singed rank test was found out to be applicable in the quantification of the change of water quality between two samples.

• 한국지반환경공학회 논문집
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• 제7권6호
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• pp.121-131
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• 2006

본 연구는 아파트공사 굴착현장에서 많이 사용하고 있는 LW주입의 지반보강효과와 환경 영향성에 대한 검토를 목적으로 수행되어 졌다. 아울러 본 연구는 투수계수가 작은 지반에서 LW공법의 지반보강효과를 현장조사 및 실내시험으로 공학적인 규명을 하였고 환경영향성 시험을 실시하여 친환경성에대한 평가를 실시 하였다. 실내시험결과 SC류인 토질성상의 지반에 대한 LW고결체는 원지반에 비해 일축압축강도는 약 3배, 전단강도정수는 약 2배 증가되고 투수계수는 6~7배 감소되어 상당한 개량효과가 있는 것으로 나타났으며 환경영향성평가 결과 pH가 초기에는 7.96까지 증가하였으나 6시간 이후부터 감소하기 시작하여 80시간 이후에는 7.30으로 초기 pH 7.25를 회복하였고, 화학성분분석 시험결과 원수와 오염수의 수소이온농도(pH)가 원수는 pH 7.36, 오염수는 pH 7.85로서 "환경부 먹는물의 수질기준"에 의거, 기준치(pH 5.8~8.5) 범위 내 이므로 환경적으로 안전하였고 원수 및 오염수에 대한 염분 및 $Cr^{6+}$ 측정 시험결과 염분은 미미하며 $Cr^{6+}$은 미검출되어 친환경적임을 알 수 있었다.

• 한국정밀공학회지
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• 제15권12호
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• pp.14-20
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• 1998

Cutting fluid is a factor which has big effects on both machinability and environment in machining process. The loss of cutting fluids may be reduced by the optimization of machining parameters in process planning. In this study, the environmental impact of fluid loss is analyzed. The fluid loss models in milling process are constructed with the machining parameters. The models are utilized to obtain the optimal machining parameters to minimize the fluid loss. The factors with significant effects on the fluid loss are analyzed by ANOVA test. Finally, optimal parameters are suggested considering both machining economics and environmental impact. This study is expected to be used as a part of a framework for the environmental impact assessment of machining process.

• 환경영향평가
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• 제4권2호
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• pp.93-103
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• 1995

This study was carried out to suggest the best statistical test to analyze the trend in monthly water quality data. Traditional parametric tests such as t-test and regression analysis are based on the assumption that the underlying population has a normal distribution and regression analysis additionally assumes that residual errors are independent. Analyzing 9-years monthly COD data collected at Paldang in Han River, the underlying population was found to be neither normal nor independent. Therefore parametric tests are invalid for trend detection. Four Kinds of nonparametric statistical tests, such as Run Test, Daniel test, Mann-Kendall test, and Time Series Residual Analysis were applied to analyze the trend in the COD data, Daniel test and Mann-Kendall test indicated upward trend in COD data. The best nonparametric test was suggested to be Daniel test, which is simple in computation and easy to understand the intuitive meaning.

• Geosciences Journal
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• 제22권6호
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• pp.1041-1052
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• 2018

A single-well push-drift-pull tracer test using two different tracers ($SF_6$ and salt) was performed at the Environmental Impact Test (EIT) site to determine suitable locations for monitoring wells and arrange them prior to artificial $CO_2$ injection and leak tests. Local-scale estimates of hydraulic properties (linear groundwater velocity and effective porosity) were obtained at the study site by the tracer test with two tracers. The mass recovery percentage of the volatile tracer ($SF_6$) was lower than that of the non-volatile tracer (salt) and increased drift time may make degassing of $SF_6$ intensified. The $CO_2$ leakage monitoring results for both unsaturated and saturated zones suggest that the $CO_2$ monitoring points should be located near points at which a high concentration gradient is expected. Based on the estimated hydraulic properties and tracer mass recovery rates, an optimal $CO_2$ monitoring network including boreholes for monitoring the unsaturated zone was constructed at the study site.

• 한국컴퓨터정보학회논문지
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• 제7권4호
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• pp.220-234
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• 2002

This study examined the impact of preventive environmental management practices on sales growth, manufacturing and environmental performance of the US chemical manufacturing companies. In order to investigate the impact, this study examined the relationship between the degree of preventive environmental programs and sales growth, manufacturing and environmental performances. Using a cross-sectional research design to test three hypotheses. a survey questionnaire was mailed to chemical companies in the USA. To investigate the relationship between the degree of Preventive environmental programs and sales growth, manufacturing and environmental performances. t-tests were used. According to the results of t-tests the higher preventive implementation programs achieved better manufacturing and environmental performances than lower preventive or reactive strategies. But there was no difference in sales growth between tow groups.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.357-360
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• 2005

Domestic enterprises are surveyed and analyzed to find the empirical relationship between environmental characteristics and electronic commerce(EC) performance. Dynamism, hostility and heterogeneity are selected as environmental characteristics. EC performance is articulated as EC utilization, EC satisfaction and EC usefulness. Empirical test presents that dynamism has a statistically significant relationship with EC performance except EC usefulness, but hostility and heterogeneity have no statistically significant relationship with EC performance. The impact of industry type on environmental characteristics and EC performance is also tested.

• 환경영향평가
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• 제4권2호
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• pp.123-130
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• 1995

The equipment composed of many complicated electronic stuffs undergoes diverse stresses caused by mechanical vibrations during its service. Thus, to ensure its proper operation in the field a simulated vibration test has to be carried out in the laboratory with the Vibration Qualification Level, the test specification, which can include the real environment. In this paper we intent to deal with method and procedure for determining the Vibration Qualification Level so as to estimate the vibration-endurance for the equipment precisely.