• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.487-492
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• 2004

Building materials are composed of very complex chemical compounds, and these indoor building materials discharge very much Volatile Organic Compounds(VOCs). We performed the environmental chamber test to investigate the Total VOCs(TVOCs) emission characteristics and emission factors about chemical and natural coating materials. As the result, we concluded that TVOCs emission are high at initial time and decreased in course of time. Natural paint was low emission level for TVOCs than chemical paint by small chamber test. The TVOCs emission factor-time profile showed a good fit with the results from the measured and predicted value.

• Journal of Environmental Science International
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• v.32 no.1
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• pp.11-24
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• 2023

This study aimed to provide preliminary data for the improvement of the tree doctor qualification test (first written test), which was newly created by enforcing the Forest Protection Act on June 28, 2018., The high demand for system improvement accelerated this study. The results were analyzeds through literature and questionnaire surveys. Writing test questions and the license of the tree doctor qualification exam are currently managed by the Korea Forestry Research Institute, and it is deemed that the test should be entrusted to Human Resources Development Service of Korea for fair and transparent management. Additionally, the plan for the improvement of the subject-wise scope of examination questions writing, difficulty of test questions, and acceptance rate of the first test should be prepared after public hearings or seminars related to the examination questions.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.487-496
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• 2022

Most of the pile's vertical static load tests in construction sites are the proof load tests, which is difficult to accurately estimate the ultimate bearing capacity and analyze the reliability of piles. Therefore, a reliability analysis method based on the proof load-settlement (Q-s) data is proposed in this study. In this proposed method, a simple ultimate limit state function based on the hyperbolic model is established, where the random variables of reliability analysis include the model factor of the ultimate bearing capacity and the fitting parameters of the hyperbolic model. The model factor M = R_uR / R_uP is calculated based on the available destructive Q-s data, where the real value of the ultimate bearing capacity (R_uR) is obtained by the complete destructive Q-s data; the predicted value of the ultimate bearing capacity (R_uP) is obtained by the proof Q-s data, a part of the available destructive Q-s data, that before the predetermined load determined by the pile test report. The results demonstrate that the proposed method can easy and effectively perform the reliability analysis based on the proof Q-s data.

• Journal of the Korean GEO-environmental Society
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• v.9 no.5
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• pp.29-36
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• 2008

The shotcrete is a NATM technique as a major tunnel support for ground stability after tunnel excavation. Instead of a general concrete lining method, it is a trend for curtail of construction periods and reduction of construction expenses that required to use of the permanent shotcrete lining. This high-strength shotcrete is required to use as a permanent shotcrete lining. This brought out the solution of environmental pollution and harmfulness to human. Accordingly, in this study specimens for strength measurement were made to develop shotcrete possible to develop materials in early with cement mineral accelerator as NATM method construction. It was compared with existing shotcrete material, unconfined compression test, flexural strength test, antiwashout underwater test were experimented. The fish poison test was experimented to evaluate an influence of environment. As a results of the test, unconfined compressive strength and flexural strength were equivalent with 28-curing day strength of existing material. An antiwashout of research subject material was revealed excellently in antiwashout Underwater test. As a results of the fish poison, an evaluation research subject material was founded more environmentally friendly than existing shotcrete.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.4.1-4.10
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• 2014

Objectives Effects of nanoparticles including zinc oxide nanoparticles, titanium oxide nanoparticles, and their mixtures on skin corrosion and irritation were investigated by using in vitro 3D human skin models ($KeraSkin^{TM}$) and the results were compared to those of an in vivo animal test. Methods Skin models were incubated with nanoparticles for a definite time period and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide method. Skin corrosion and irritation were identified by the decreased viability based on the pre-determined threshold. Results Cell viability after exposure to nanomaterial was not decreased to the pre-determined threshold level, which was 15% after 60 minutes exposure in corrosion test and 50% after 45 minutes exposure in the irritation test. IL-$1{\alpha}$ release and histopathological findings support the results of cell viability test. In vivo test using rabbits also showed non-corrosive and non-irritant results. Conclusions The findings provide the evidence that zinc oxide nanoparticles, titanium oxide nanoparticles and their mixture are 'non corrosive' and 'non-irritant' to the human skin by a globally harmonized classification system. In vivo test using animals can be replaced by an alternative in vitro test.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1199-1204
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• 2005

The purpose of field monitoring system in KHC-Test Road located at Joongbu-Inland Highway, is to provide the performance data for traffic and environmental loadings from pavement surface. Among them, water content reflectometers(WCR) are used to measure the volumetric water content of subgrades soils used in test roads. However, most of the WCRs are not well-calibrated based on the field conditions. In this study, the laboratory based test is performed at various density conditions to evaluate the volumetric water content in subgrade Soils with a WCR. Based on the laboratory testings, the effect of density on WCR measurement are well evaluated for predicting the volumeric water content.of subgrades soils in KHC-Test road.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.819-824
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• 2010

Model test was performed for new earth retention system that is a kind of truss tower with non-supported excavation. For the model test, a dimensional analysis of the full-scaled truss tower system was performed. The horizontal displacement of the wall, bending stress acting on TTS system were measured during construction simulation. From the measurements, the performance of the truss tower system was investigated.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.107-113
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• 2010

This paper presents the prediction of shear strength of oil contaminated clay using fall cone test used to determine the liquid limit of soil. The penetration depth of fall cone is related to water content of soil. Laboratory vane shear can also be related to water content. To explore the relative correlation between penetration depth of fall cone and laboratory vane shear, both fall cone tests and laboratory vane shear test were carried out with water contents of soil. The developed empirical relationships in this studys showed that the shear strength is reduced to 3.9% with 1% increase of oil content. And, the lesser initial water content of contaminated clay, the more shear strength of contaminated clay is affected by oil content.

• International Journal of Reliability and Applications
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• v.11 no.1
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• pp.55-67
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• 2010

There has been a recent upsurge in demand for the improvement of car reliability in the Northern American which is the primary market of South Korea automobile industry. It has been required that the warranty for transmission control unit for passenger cars directly related to passenger safety or security should be extended for 10 years and 160,000 km. In this paper, the test method for reliability and evaluation criteria is presented to evaluate the reliability on the automatic transmission controller. Reliability certification test can be roughly divided into two types: a quality test and life assessment test and a quality test can be subdivided into a basic performance test and environmental resistance test. There are 3 types of tests on the performance test for automatic transmission controller and environmental resistance test is composed of 14 items. Life test is performed with only the product passed this quality test. In this study, operation limit test at the high-temperatures, accelerated life test under specific temperature and accelerated life test for 2 or 3 stress levels are shown as a way for life test.

• Nuclear Engineering and Technology
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• v.43 no.1
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• pp.83-88
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• 2011

To define the effect of strain rate variation from 0.04% to 0.004%/s on environmental fatigue of CF8M cast stainless steel, which is used as a primary piping material in nuclear power plants, low-cycle fatigue tests were conducted at operating pressure and temperature condition of a pressurized water reactor, 15 MPa and $315^{\circ}C$, respectively. A high-pressure and high-temperature autoclave and cylindrical solid fatigue specimens were used for the strain-controlled low-cycle environmental fatigue tests. It was observed that the fatigue life of CF8M stainless steel is shortened as the strain rate decreases. Due to the effect of test temperature, the fatigue data of NUREG-6909 appears a slightly shorter than that obtained by KEPRI at the same stress amplitude of $1{\times}10^3$ MPa. The environmental fatigue correction factor $F_{en}$'s calculated with inputs of the test data increases with high strain amplitude, while the $F_{en}$'s of NUREG-6909 remain constant regardless of strain amplitude.