• Hwankyungkyoyuk
• /
• v.22 no.2
• /
• pp.79-91
• /
• 2009

The purpose of this study is to find out the influence of the urban stream investigation on elementary school students' environmental conservation awareness. The urban stream investigation was applied to the experimental group and the control group has been taught by the traditional teaching method focused on the teacher's lecture. To analyze the effect of urban stream investigation, the pre- and post-tests on environmental conservation awareness composed of interest in living things, perception about water pollution and environmental conservation were applied to the both groups. The results were analyzed by One-way ANOVA and ANCOVA. As a result, there were not significant difference between the experimental and the control group in the pretest(p>.05). In the post-tests on the student's interest in living things, perception about water pollution and environmental conservation the scores of the experimental group were higher than those of the control group(p<0.05). Therefore, the urban stream investigation made a positive effect on improving of elementary school students' environmental conservation awareness.

• Journal of the Korean GEO-environmental Society
• /
• v.8 no.6
• /
• pp.61-68
• /
• 2007

The problem on cyclic plate load tests was analyzed by finite element method using an anisotropic hardening constitutive model. The constitutive model was coded to user subroutine in ABAQUS. Using the result of the analysis, Young's moduli corresponding to various strain levels were evaluated by a back calculation method and were very similar to those of input. On the basis of the back calculation method plate loading tests were verified. As a result, deformation moduli could be evaluated practically from cyclic plate load tests with respect site conditions.

• Journal of Environmental Science International
• /
• v.7 no.3
• /
• pp.361-368
• /
• 1998

The structure such as building and cultural properties was composed of various materials like wood, metal and stone that have been utilized and exposed to air, wind and rain far a long time. However, because of their special characteristics as structure, collecting of samples that may involve their destruction cannot be permitted, ever for material analysis. Therefore, h order to study the Influence of atmospheric pollution on structure, atmospheric corrosion tests were achieved by making use of materials(bronze. ancient copper, copper, steel and marble) in field exposure tests. Atmospheric exposure sites are selected from places which are characterized by urban, rural, Industrial and marine enoronments In Northeast Asia. According to the results of atmospheric corrosion tests: The corrosion rates of Industrial states In china were more serious than other sampling sites. In the correlation of meteorological factors. wet hours was defiled as Intogeacted hours under that atmospheric temperature is above $0^{\circ}C$ and relative humidity in above 80% that has a great influence on corrosion tests of materials in case of a short time. The relative humidity was above about 75% that resulted in great increase of corrosion rates. In the esimation of corrosion rates between materials, corrosion rates of steel was about thirty times and decuple larger than that of other materials excluding marble in unshelterd exposure and In sheltered exposure.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.6
• /
• pp.801-806
• /
• 2004

The pilot study was conducted to (i) investigate the ability of various membrane integrity monitoring methods to detect changes in membrane integrity during operation, and (ii) determine the impact of membrane damage on microbial removal by microfiltration. Two variations of air pressure hold tests were investigated for direct integrity monitoring: pressure decay (PD) and diffusive air flow (DAF) tests which are most commonly used integrity tests for microfiltration (MF) membranes. Both PD and DAF tests were sensitive enough to detect one damaged fiber out of 66,000 under field operaing conditions. Indirect integrity monitoring such as turbidity and particle counting, however, responded poorly to defects in membrane systems. Microbial challenge study was performed using both new and deliberately damaged membranes, as well as varying the state of fouling of the membrane. This study demonstrated that MF membrane with nominal pore size $0.2{\mu}m$ was capable of removing various pathogens including coliform, spore, and cryptosporidium, at the level required by drinking water regulations, even when high operating pressures were applied. A sharp decrease in average log reduction value (LRV) was observed when one fiber was damaged, emphasizing the importance of membrane integrity in control of microbial contamination.

• Journal of Applied Reliability
• /
• v.16 no.2
• /
• pp.118-124
• /
• 2016

Purpose: The purpose of this paper is to suggest an environmental test plan for reducing early failure. Methods: We study the preferred test design and tests that are performed substantially in the company. We investigate the environmental profile on the actual supply chain and identify the effectiveness for this test design. Results: Proposed sequential test designed to implement the supply chain on the environment profile showed more effective results compared to existing tests. Conclusion: Suggested sequential test in this paper will be an effective guidance for the given environment test.

• Journal of Environmental Science International
• /
• v.18 no.2
• /
• pp.187-195
• /
• 2009

This study was investigated to control the corrosion and scale at the cooling water system in steel works. Laboratory and field tests were performed for the indirect cooling water system of plate mill. Throughout the experiment, various factors such as leakage of pipes, heating rate and capacity, and the reaction between existing and substitute inhibitors were carefully monitored. The results showed that the harmful effect of high temperature could be minimized, and satisfactory corrosion/scale controls were effectively achieved using inhibitor, even at the increased temperature of $80^{\circ}C$. The batch and field tests in the gas scrubbing cooling water system of blast furnace and cooling water system of corex plant indicated that the new inhibitor was more effective for the prevention of corrosion and scale than the existing one.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.703-704
• /
• 2010

The environmental tests simulating the flight condition have been performed to manufacture the high reliable safety and arming device(SAD). A motor assay in preliminary design was reinforced with the structure to resist severe vibration and shock environment, and the design change had been verified by conducting the principal environmental test again.

• Environmental Engineering Research
• /
• v.23 no.3
• /
• pp.282-287
• /
• 2018

Three different methods of bacterial viability monitoring were compared to detect chemically or thermally inactivated Escherichia coli. Direct colony enumeration, live/dead bacterial cell staining with a fluorescent dye, and the dehydrogenase activity assay were compared with respect to their ease of use and time required to perform the three different tests. The green (live cell)/red (dead cell) ratio obtained from the fluorescent bacterial cell staining approach showed a linear relationship with the colony forming units; the result obtained with dehydrogenase was similar to those. The sensitivity of the monitoring methods to detect bacterial deactivation varied with different disinfection conditions. After thermal treatment, the sensitivity of the staining approach was lower, while that of the dehydrogenase activity assay was the highest. After chemical treatment, the sensitivity of detection for both methods was similar.

• Environmental Engineering Research
• /
• v.24 no.1
• /
• pp.82-90
• /
• 2019

Meeting the regulations based on the short-term leaching tests may not necessarily assure the environmental and human health safety of reusing mine wastes. This study investigated heavy metal leachability of four metal mine waste samples (e.g., Z, Y, H, and M) and human health risk of reusing them as construction materials. The heavy metal leachability did not depend on the total heavy metal contents. For example, the Z sample contained greater amounts of As and Fe than Zn, but the leachates contained only Zn at a detectable level. This can be attributed to the crystalline structure and heavy metal fractions of the mine wastes. The leaching test results suggested that the four mine waste samples are potentially reusable. But the Z and M samples reused in industrial areas imposed carcinogenic risks. This was largely attributed to As that is exposed via dermal contact. The Y and H samples reused in residential areas imposed carcinogenic risk. The major exposure route was the ingestion of crops grown on the mine wastes and Cr was the major concern. The two-stage assessment involving leaching tests and risk assessment can be used to promote safe reuse of mine wastes.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1709-1714
• /
• 2004

Pressurization system of a 50m unmanned airship was manufactured according to the detailed design. In this paper. the whole procedures including system design. simulation and fabrication were described. The fabricated part were ground tested to check compliances with design requirements. Ground tests include operational tests, leakage tests, endurace tests and low temperature environmental tests. Results shows pressurization system of a 50m unmanned airship meets design requirements. Currently. pressurization system is installed to the KARI airship, Via 50m and performance verification through the flight tests are being conducted.