• Journal of the Korean Data and Information Science Society
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• v.14 no.1
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• pp.23-35
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• 2003

This paper provides the checklist of statistical methods in the water environmental research of Han and Nakdong river basins in South Korea. There are many errors pointed out in adopting statistical methods for the researches, as an example, basic statistical assumptions are missed for t-tests or regression analyses. Some new ideas are proposed for better researches of the river basins in Korea.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.05a
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• pp.42-43
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• 2001

Ecotoxicology is a research area for adverse effect of chemicals to ecosystem. While toxicology is directly related to human health, relation between ecotoxicology and human health is indirect. In this connection, public awareness of environmental effect has been rather behind that for health effects. Historically the first concern in ecotoxicology was adverse effect of pollution on organisms in waters receiving industrial wastewater. (omitted)

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.69-72
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• 2008

This study is designed to understand changes in fire resistance performance of intumescent coating system through follow-up tests on temperature of unexposed surface for the domestic intumescent coating system by environmental testing procedure.

• Journal of the Korean GEO-environmental Society
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• v.18 no.2
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• pp.29-37
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• 2017

As the behavior of the debris flow due to the torrential rains in mountain is affected by shear strength and rheological properties of the fine fraction in the ground, the evaluation of both properties is necessary to estimate the behavior of the debris flow. The objective of this study is to evaluate the shear strength and rheological properties using the direct shear apparatus. The direct shear tests are conducted for two kinds of fine-grained soil specimens, which are in dry state and liquid limit state. From the direct shear tests, shear strengths are measured according to the normal stresses applied on the specimens to evaluate the cohesion and internal friction angle. In addition, reversal shear tests are performed for the fine-grained soil specimens in liquid limit state according to the shear rate to evaluate the residual shear strength. The results of direct shear tests show that the specimen at the liquid limit state has lower internal friction angle and higher cohesion compared to the dry stated, and the residual friction angle and cohesion at the residual state are lower than those at the peak state. In the result of reversal shear test, the residual shear strength is directly proportional to the shear rate and viscosity is calculated as $73.60Pa{\cdot}s$. This study demonstrates that the direct shear apparatus can be effectively used for the evaluation of the shear strength and rheological properties of the fine-grained soils related with the debris flow.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.353-361
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• 2005

In this study, we performed whole effluent toxicity(WET) test and compared the biological component analyses tests for some streams into which wastewater treatment plant effluents are discharged. The test procedures for the WET test and the biological component analysis were conducted according to U.S. EPA guidelines and the Ohio EPA wading method. The WET tests based on the test species of D. manga and S. capricornutum All treatment plants showed a S. capricornutum toxicity, and at 7 sites, except A and J, we could observe a D. magna toxicity. The highest toxicity was observed at site D and this were followed by E and F. The biological component analyses applied to the effluent discharged stream. We found that total species were low at sites C1, D1 and J1 and the low number of total individuals were observed at sites A1, C1, E1, H1, and J1 compared to the controls and other sites. The species richness was low at sites A1, B1, C1, D1, and J1. The species change was evident at site D(D1) and the tolerant species was predominant. The biological analyses and WET tests suggested that the effluents resulted in massive ecosystem impact.

• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.49-54
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• 2016

An active layer distributed on surface of an extreme cold region causes a frost heave by repeating the freezing and thawing according to the seasonal temperature change. Since the height of frost heave is greatly affected by the thickness of active layer, an accurate evaluation of the thickness of active layer is necessary for the safe design and construction of the infrastructure in the extreme cold region. In this study, dynamic cone penetrometer, which is miniaturized in-situ penetration device, is applied for the evaluation of active layer depth distribution. As the application tests, two dynamic cone penetration tests were conducted on the study sites located in Solomon and Alaska. In addition, ground temperature variations were obtained. As the results of the application tests, the depth of interface between the active layer and the permafrost was evaluated from the difference in dynamic cone penetration indexes of the active layer and the permafrost, and a layer was detected around the interface considered as an ice lens layer. Also, the interface depths between the above zero and the below zero temperature determined from the ground temperature variations correspond with the interface depths evaluated from the dynamic cone penetration tests. This study demonstrates that the dynamic cone penetrometer may be a useful tool for the evaluation of the active layer in the extreme cold region.

• Journal of the Korean GEO-environmental Society
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• v.7 no.3
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• pp.77-83
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• 2006

The purpose of this study is to analyze lateral displacement behavior of clay layers in case of the banking in soft ground through model tests. Seven model tests varying with thickness of soft clay and loading velocity are performed to correlate between ground heaving and loading velocity. In case of low loading velocity, vertical settlement below loading plate and small ground heaving are obviously observed. In case of the high loading velocity, it is shown that both soil displacement at the end of a loading plate and surface heaving are large. In addition, the calculated displacements show good agreement with three cases of field measurements in clay with high moisture contents so that we can predict the range of heaving area and the amount of heaving.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.222-229
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• 2007

Environmental tests should be carried out to show that design performance is in an operational condition in an actual operational environment to assure maintainability and reliability. Aero-products electromagnetic compatibility tests are performed mainly for the individual parts and Specifications MIL-STD-461E and RTCA DO-160E are developed for the military and commercial parts tests respectively. The MIL-STD-461E which is a military environmental test standard is targeting all munitions and that user can apply by selecting applicable requirements from this specification. On the other hand, requirements are applied exclusively for the Avionics Equipments in commercial test standard.

• Korean Journal of Environmental Agriculture
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• v.8 no.2
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• pp.119-127
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• 1989

The minimum concentrations of nonionic and anionic surfactants inducing phytotoxicity were investigated after spraying or flooding surfactant solutions to annual plants. Of the sufactants tested, LE, NP, SPSS, LN, PAAS and DBC induced phytotoxicity at the lowest concentrations through all treatments and Tween, Span, SP, SC, STPP and CLIS induced the least phytotoxicity even at high concentration. At flooded paddy field tests, anionic surfactants induced phytotoxicity at the lower concentration than nonionic, but showed similar tendencies with other treatments. In pre-emergence treatments of upland and dry paddy field tests, there was little phytotoxicity induced at over 10 percent, while phytotoxicity was induced at the lowest concentration among 6 treatments in flooded paddy field tests.

• Journal of Environmental Health Sciences
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• v.38 no.1
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• pp.1-7
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• 2012

Carbon nanotubes (CNTs) stand at the frontier of nanotechnology and are destined to stimulate the next industrial revolution. Rapid increase in their production and use in the technology industry have led to concerns over the effects of CNT on human health and the environment. The prominent use of CNTs in biomedical applications also increases the possibility of human exposure, while properties such as their high aspect ratio (fiber-like shape) and large surface area raise safety concerns for human health if exposure does occur. It is crucial to develop viable alternatives to in vivo tests in order to evaluate the toxicity of engineered CNTs and develop validated experimental models capable of identifying CNTs' toxic effects and predicting their level of toxicity in the human respiratory system. Human lung epithelial cells serve as a barrier at the interface between the surrounding air and lung tissues in response to exogenous particles such as air-pollutants, including CNTs. Monolayer culture of the key individual cell types has provided abundant fundamental information on the response of these cells to external perturbations. However, such systems are limited by the absence of cell-cell interactions and their dynamic nature, which are both present in vivo. In this review, we suggested two viable alternatives to in vivo tests to evaluate the health risk of human exposure to CNTs.