• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.676-683
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• 2003

A laboratory experiment using artificial fracture rocks was used to understand the 3-dimensional dispersion of a tracer and the mixing process in a fractured network. In this experiment, 12cm polystyrene foam cubes with two electrodes for monitoring electric conductivity (EC) were used as artificial fractured rocks. Distilled water with 0.5mS/m was used as a tracer in water with 35mS/m and the difference of EC between the tracer and the water was monitored by a multipoint simultaneous measurement system of electrical resistance. The results showed that even if the fracture arrangement pattern was not straight in the direction of the flow, the tracer did not diffuse along individual fractures and an oval tracer plume, which was the distribution of tracer concentrations, tended to be form in the direction of the flow. The vertical cross section of the tracer distribution showed small diffusivity in the vertical direction. The calculated total tracer volume passing through each measurement point in the horizontal cross section showed while that the solute passed through measurement points near the direction of hydraulic gradient and in other directions, the passed tracer volumes were small. Using Peclet number as a criterion, it was found that the mass distribution at the fracture intersection was controlled in the stage of transition between the complete mixing model and the streamline routing model.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1372-1377
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• 2009

For the remediation of the subsurface contaminated by nonaqueous phase liquids(NAPLs), it is important to characterize the NAPL zone properly. Conventional characterization methods provide data at discrete points. To overcome the weak points of conventional characterization methods, the partitioning tracer method has been developed and studied. The average saturation of NAPL($S_n$), which is the representative and continuous saturation value within contaminated site, can be calculated by comparing the transport of the partitioning tracers to that of the conservative tracer in the partitioning tracer method. In this study, the application of the partitioning tracer method in heterogeneous media was investigated. To represent the heterogeneous condition of subsurface, a two-dimensional soil box was divided into four layers and each layer contained different sized soils. Soils in the soil box were contaminated by the mixture of kerosene and diesel, and partitioning tracer tests were conducted before and after the contamination using methanol as conservative tracer and 4-methyl-2-pentanol, 2-ethyl-1-butanol, and hexanol as partitioning tracers. The response curves of partitioning tracers from contaminated soils were separated and retarded in comparison with those from non-contaminated soils. The contamination of soils by NAPLs, therefore, can be detected by partitioning tracer method considering these retardations of tracers. From our experiment condition, the average saturation of NAPLs calculated by partitioning tracer method using the methanol as conservative tracer and hexanol as partitioning tracer showed the highest accuracy, though all results were underestimated. Further studies, therefore, were needed for improving the accuracy using the partitioning tracer test in heterogeneous media.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권1호
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• pp.66-72
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• 2010

The partitioning tracer method is to estimate the residual saturation of nonaqueous phase liquid (NAPL) in soils by analyzing tracer's retardation induced by the reversible partitioning of tracer with NAPL. This study is to estimate the residual diesel saturation in soils using the partitioning tracer method. Two-dimensional soil box was used to represent the 2-dimensional flows of groundwater and tracer solution in the saturated aquifer, and the soil box was filled with soil and then saturated with water. The residual diesel saturation was induced in saturated soil, and the partitioning tracer method was applied. The results from batch-partitioning experiment indicated that the diesel-water partitioning was linear with respect to tracer's concentration, and the partition coefficient of tracer between diesel and water was measured by their linearities. The groundwater flow in the saturated aquifer was simulated in the 2-dimensional soil box, and the residual diesel contamination was visually identified. The results from the partitioning tracer method with or without diesel in soils confirmed that 4-methyl-2-pentanol, 2-ethyl-1-butanol and 1-hexanol, can be used as a detecting method for diesel contamination. By the accuracies of estimations for diesel contamination using the partitioning tracer method, 2-ethyl-1- butanol showed the highest accuracy with 83%.

• 한국대기환경학회지
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• 제12권5호
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• pp.529-540
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• 1996

Dispersion experiment using SF$_{6}$ tracer was performed in the flat field of Chunchon Basin during four nights from August 29 to September 2, 1991. The purpose of this study is to analyze toe horizontal distribution of tracer concentration under the strong stable conditions and to evaluate the results calculated by INPUFF model. Incase of high wind speed, plume spread of SF$_{6}$ concentration appeared in narrow area of the downwind and the standard deviation of the horizontal wind angle (.sigma.$_{a}$) was amall. However, the SF$_{6}$ was spread widely in cases of low wind speed because of the large .sigma.$_{a}$. The result of the INPUFF model was similar to the observed distribution of the SF$_{6}$ concentration. It is proved that the Gaussian puff model is useful when wind direction varies significantly.tly.tly.tly.

• 한국수처리학회지
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• 제26권6호
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• pp.3-12
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• 2018

The objective of this study was to evaluate the radius of influence of effluent of water treatment system developed for the purpose of improvement of reservoir water quality using fluorescent dye (Rhodamine-WT) tracer experiment and 3-D numerical model. The tracer experiment was carried out in a medium-sized agricultural reservoir with a storage capacity of $227,000m^3$ and an average depth of 1.6 m. A guideline with a total length of 160 m was installed at intervals of 10 m in the horizontal direction from the discharge part, and a Rhodamine measurement sensor (YSI 6130, measurement range $0-200{\mu}g/L$) was used to measure concentration changes in time, distance, and depth. Experimental design was established in advance through Jet theory and the diffusion process was simulated using ELCOM, a three dimensional hydraulic dynamics model. As a result of the study, the direct effect radius of the jet emitted from the applied water treatment system was about 50-70 m, and the radius of physical effect by the advection diffusion was judged to be 100-120 m. The numerical simulations of effluent advection-diffusion of the water treatment system using ELCOM showed very similar results to those of the impact radius analysis using the tracer experiment and jet flow empirical equations. The results provide valuable information on the spatial extent of the water quality improvement devices installed in the reservoir and the facility layout design.

• 한국대기환경학회지
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• 제14권5호
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• pp.397-410
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• 1998

Tracer experiments were performed 4 times in December 1992 on the relatively flat terrain and nearby building area adjacent to the Taedok Science Town in Korea. Each experiment was continued for relatively short period of 1 or 2 hours with intermittent release of SF6 up to 2.07g/s at 10m height. Movement of tracer plume was tracked by a continuous tracer analyzer installed on an air monitoring van. Simulation with INPUFF was carried out to analyze and predict experiments. Measured profiles of tracer plume were narrow and sharp while predicted profiles by INPUFF were broad and slowly varied. Tracer plumes were detected at a short distance of 0.5 to 2.2 km mainly due to intermittent release and high value of lower detectable limit. Various experimental conditions were tested by INPUFF simulation in order to find desirable conditions. Higher wind speed and less variable wind direction could yield longer distance of plume tracking only when the lower detectable limit was sufficiently low. Distance of plume tracking was long and did not much depend on the lower detectable limit in stable atmospheric conditions.

• 한국대기환경학회지
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• 제5권2호
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• pp.84-96
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• 1989

To evaluate the short term air pollution dispersion model, the diffusion experiment was conducted on the flat terrain near Chuncheon. Sulfur hexafluoride $(SF_6)$ gas was used to determine the horizontal spread of plume $(\sigmay)$ for calculated by CRSTER model. Results show that CRSTER model underestimates $\sigma$y because averaging time adjustment is not applied to calculate the $\sigma$y. The scheme that can estimate the atmospheric stability more accurate than Turner method, was presented.

• 방사선산업학회지
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• 제6권1호
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• pp.41-47
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• 2012

A field tracer experiment using a radioisotope was conducted to analyze the transport and dispersion characteristics of pollutants in the coastal area near a Wolsung. A rod float including GPS was released to track the paths of radioisotope. NaI detector was installed to measure the released radioisotope from the boat, and measurements were performed with the real time. The measured tracer data by a field experiment can be used as the basic data for understanding the transport characteristics of pollutants and verifying numerical models near the offshore.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.99-104
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• 2007

Tracer gas technique is widely used to measure the ventilation rates and/or ventilation effectiveness of building spaces. However, the conventional method using a single tracer gas can measure only outdoor air change rates in a single zone. This paper deals with the multi-gas tracer technique to measure air exchange rates between rooms. Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Experiments are conducted in a simple two-room model with known airflow rates using tracer gases of SF6 and R134a. The concentration decays of two tracer gases are measured after simultaneous injections in each room. The governing equations are derived from the continuity and the mass balance of each room. The data reduction procedure are developed to obtain the inter-room airflow rates using the governing matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, smoothing, and etc, to improve the estimate and interpretation of the results.

• Journal of Korean Society for Atmospheric Environment
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• 제10권E호
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• pp.357-370
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• 1994

지역 규모 대기 모형과 결합된 오일러 장거리수송 모형이 제시되었다. 이 모형을 Cross-Appalachian Tracer Experiment (CAPITX)의 2개 사례에 나타난 추적물 농도 분포 모사에 적용하였다. 기상장은 CSU RAMS에 4차원 자료 동화 기법을 도입하여 도출하였고, 추적물 수송은 오일러 확산 모형으로 계산된다. 4차원 자료 동화 기법을 포함한 대기 모형은 관측과 잘 일치하는 기상장을 도출하였으며, 장거리 수송 예측에 이용될 다양한 기상 자료의 도출을 위한 매우 적절한 도구가 될 수 있음을 보였다. 이 연구에서 개발된 수송 모형은 관측 농도 분포가 복잡한 구조를 보인 사례에 대해서는 부분적인 성공을 거두었으나, 대체로 관측된 추적물 수송을 유사하게 모사하였다. Bott's 2nd-order scheme을 사용한 결과는 Bott's 4th-order scheme을 사용하고 명시적인 수평 확산을 증가시킨 경우와 유사한 수행 능력을 보였다. 이 대기 모형과 수송 모형은 상세한 구름 및 화학 과정들을 고려한 산성 침적 모형의 훌륭한 기본 틀이 될 수 있을 것으로 생각된다.