• Journal of Environmental Science International
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• v.23 no.7
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• pp.1269-1275
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• 2014

Ecotoxicity assessments with the physiochemical water quality items and the bioassay test using Daphnia magna were conducted for 18 selected effluents of 6 industrial types (metal processing, petroleum refining, synthetic textile manufacturing, plating, alcohol beverage manufacturing, inorganic compound manufacturing) being detected toxicity from industrial effluent in Ulsan city, and the interrelationship between total toxic unit (${\Sigma}TU$) and concentrations of Water Quality Conservation Act in Korea were investigated. The average toxic unit(TU) of effluents for 6 industrial types displayed the following ascending order: petroleum refining (0.2) < synthetic textile manufacturing (0.6) < alcohol beverage manufacturing (0.9) < metal processing (1.3) ${\leq}$ inorganic compound manufacturing (1.3) < plating (3.0). These values were less than effluent permission standard. Based on the result of substances causing ecotoxicity, the correlation analysis was not easy because most of heavy metals were not detected or were less than effluent permission standard. Toxicological assessment of industrial effluent was suitable for the evaluation of the mixture toxicity for pollutant. The whole effluent toxicity test using a variety of species was needed for the evaluation of industrial wastewater.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.1-12
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• 2019

In this study, TI(Toxic Index) of Daphnia toximeter corresponded to ecological toxicity standard 1 TU(Toxic Unit) was set up using Daphnia toximeter and when operating NOEC(water quality standards for drinking water) and $EC_{50}$ Daphnia toximeter alarm was issued appropriately, which enables real time ecological toxicity evaluation. I studied to get a good shot and the research was conducted by investigating domestic and international related data and conducting a preliminary study. 6 of 59 hazardous substances (As, Hg, Cr, Diazinon, Dioxane, and Phenol) recommended by the water quality monitoring items for artificial river water were selected and static, dynamic and quality management test, TI was shown to be good in other materials except Diazinon, and as a result of $EC_{50}$ spiking test, TI was matched to TU by distinguishing between 1 TU and 1 TU. in suggesting the complementary point of ecological toxicity management system and the future of research on water Daphnia toximeter.

• Journal of the Korean Geotechnical Society
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• v.24 no.5
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• pp.37-54
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• 2008

The standard construction manual of the SDA (Separated Doughnut Auger) piling method was proposed so that the resisting capacity of the augered piles could work effectively. 438 dynamic pile load tests were performed on 379 test piles, which were installed at 36 sites in Korea by the SDA piling method with application of various water-cement ratio of cement milks. The dynamic pile load test results showed that the bearing capacity of the SDA augered piles depended on the water-cement ratio of cement milks. And couple of the formulas were presented according to water-cement ratio and various grounds to estimate quantitatively both the unit end bearing and the unit frictional capacity of the SDA augered piles. It was also considered that the water-cement ratio of cement milks exerts an influence on the bearing capacity of the SDA augered piles. The presented formulas were compared with the existing formulas, which were presented by several standard design codes to design the augered piles.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.232-328
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• 2001

This paper investigates the influences of water content and viscosity agent on the bleeding of concrete. According to test results, fluidity shows decline tendency as water content decreases, and dosage of viscosity agent increases. PEO viscosity agent does not affect the air contents while, MC viscosity agent causes air loss. As for bleeding, bleeding decreases with decrease of water content. As dosage of viscosity agent increase, bleeding decreases, regardless of viscosity kinds. It is thought that viscosity agents have the favorable effect of reducing bleeding, if fluidity and air loss are improved.

• Nuclear Engineering and Technology
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• v.31 no.5
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• pp.506-511
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• 1999

The pilot system for radioactive liquid laundry waste was developed with treatment capacity, 1ton/hr and set up in the Yong Kwang unit #4. The system is composed of tank module, RO systems and a UV/$H_2O$$_2$photo-oxidation unit. The RO system consists of the BW unit (low-pressure RO for brackish water desalination) and the SW unit (high-pressure RO for seawater desalination). The BW unit possesses 4 RO membranes and it can reduce the feed water volume down to 1/10. This concentrated feed water can be reduced again up to 1/10 in its volume in the SW unit composed of 4 RO membranes. The UV/$H_2O$$_2$ photo-oxidation process unit was used for the detergent degradation. The operation of the pilot system was carried out and verified in its capability through the continuous operation and concentration operation using the actual liquid waste from the power plant. The design criteria and data for industrialization were yielded. The efficiency of the UV/$H_2O$$_2$ photo-oxidation process and the optimum operational procedure were evaluated. The decontamination factors for radioactive cobalt and cesium were measured. This on-site test showed the experimental result in the DF$\geq$300 and volume reduction factor$\geq$100.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.632-637
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• 2014

Proficiency testing by interlaboratory comparisons is used to determine the performance of individual laboratories. In order to verify the quality of acute toxicity testing with Daphnia magna, National Institute of Environmental Research in South Korea is regularly organizing interlaboratory comparisons to estimate the analytical accuracy of different laboratories. Total 58 laboratories located in South Korea took part in interlaboratory proficiency testing scheme with three proficiency testing samples. TU(Toxic Unit) values of each laboratory were determined and robust z-score was calculated in order to evaluate the proficiency levels. Based on the robust z-score classification, 74% of the participant laboratories showed a satisfactory performance (43 laboratories). The main reason of 'unsatisfactory' performance seemed to be considered that the unsuitable management of test organism incubation system and the lack of experience on the identification of the test organism condition by effect of toxicity.

• Journal of the Korean Geosynthetics Society
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• v.6 no.2
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• pp.17-20
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• 2007

In this study, a series of uniaxial unconfined compression test and constant-head test were performed to investigate the mechanical characteristics of porous concrete using recycled-aggregate for the varying unit weight and water-cement ratio. To enhance the permeability of the porous concrete, the recycled-aggregate with similar grain size in the range of $40{\pm}5mm$ was used and water-cement ratio that leads to the lean-mix was adapted. The mechanical characteristics of the porous concrete cured for 3 days were examined; the compressive strength and $E_{50}$ showed their maximum values with 40% water-cement ratio and $1.8t/m^3$ unit weight and the permeability coefficient was averagely measured in the range of $0.9{\times}10^0cm/sec$ regardless of water-cement ratio and unit weight.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.4
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• pp.397-406
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• 2009

This study was conducted to monitor the floc sizes forming in the mixing zone in the water treatment plant. The dosing amount of poly aluminium chloride(PAC) was determined by particle dispersion analyzer(iPDA) in the lab and field scale test. During a field test period, PAC coagulant was used and the raw water was taken from Nakdong river. PAC wad diluted to activate the coagulant, leading to bring the more homogeneous dispersion in the shorter time. To monitor the floc sizes, the unit of floc size index(FSI) was used. With increasing of raw water turbidity, FSI value was increased. Also, the increased dosing amount of PAC brought the increased FSI and with overdosing of coagulant was in turn decreased. When the PAC was fed into the raw water after dilution in a field scale test, the width of FSI was narrower compared with the feeding of the mother liquor of PAC, implying that the formed flocs are denser and more uniform sizes. The width of FSI in average was varied on depending on the basicity of coagulant. Also, dF value, fractal dimension was evalued with the different coagulants, showing from 2.01 to 2.03. On-line floc monitor was effective for the optimal dosing in the drinking water plant.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.84-89
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• 2000

Parametric studies based on laboratory pilot tests were performed to investigate the relationships between electrical resistivity and contaminated soil properties. Three kinds of sandy soils sampled and leachates from a industrial waste landfill were mixed to model the contaminated soils. Electrical resistivity of soils were measured by using a simulated resistivity cone penetrometer probe. In the experiments, the electrical resistivity were observed with changing the water content, void ratio, unit weight, degree of saturation, and concentration of the leachate. The test results show that the electrical resistivity of soils depends largely on the water content and the electrical property of pore water rather than unit weight and types of soils.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.519-524
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• 2007

In this study, NR GT 101 (water-to-water Ground source heat pump unit) and NR GT 102 (water-to-air Ground source heat pump unit) related with ISO and ARI guideline were introduced and researched. GSHPs testing was performed by NR GT 101, 102 and analyzed performance factors. Test result, Energy Efficiency Ratio and Coefficient of performance factor of GSHPs were relatively low at an average value rather than Certification.