• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.11
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• pp.606-612
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• 2009

Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Tracer gas techniques are widely used to measure ventilation rates, ventilation effectiveness, and interzonal air movements. Depending on the number of gases used, they are divided into single and multi tracer gas methods. This paper deals with the comparison of the tracer gas methods in measuring air exchange rate between rooms. Experiments have been conducted in a simple two-room model with known airflow rates. In multi-gas procedure, the concentration decays of two tracer gases, i.e SF6 and R134a are measured after simultaneous injections in each room. The single tracer gas method is also applied by injecting SF6 gas with a time lag between two rooms. The data reduction procedures are developed to obtain the interzonal airflow rate using the matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, and smoothing. Uncertainty for each airflow rate is investigated depending on the parameters based on the setting values.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.39-45
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• 2017

We present a Brownian dynamics simulation study on the diffusion of a neutral tracer particle confined in a regularly crosslinked polymer network, especially, when the tracer size is comparable to the mesh size of the network. Polymer networks with different mesh sizes are prepared and compressed to the extent that the total polymer densities become the same. Irrespective of the network mesh size, the tracer diffusion in the networks is slowed down, showing the subdiffusion on intermediate time scales followed by the normal diffusion at long times. However, the confinement effect on the tracer diffusion becomes more significant when network strands are tightly stretched with smaller mesh size. The time scales of dynamic transitions are analyzed in terms of the probability distribution of time-correlated particle displacements.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.407-410
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• 2006

Studies were performed on evaluating the applicability of activated carbon bugs on dye tracer tests as tracer detectors by using its adsorption isotherm of the grained activated carbon. We preliminary conducted several standard adsorption and extraction tests and obtained the relationship between standard dye solution and detected concentrations from activated carbon samples in dry and wet conditions. the slopes of the regression line were 0.71 for wet condition and 0.74 for dried one. Field dye tracer tests were performed in a karst area, where several faults occur along a stream and pass the test area. We sampled water samples and activated carbon samples at three points in Hwangji Pond, where groundwater outflows from the karst conduit. According to the results of breakthrough curve analysis, the regional flow along the conduit, which is assumed to cause a karst conduit, was estimated as 0.18 m/day. The relationship between the concentrations of water sample and extracted activated carbon bugs shows the similar slopes with those from standard solution tests. This suggests that activated carbon could be useful as a dye tracer detector because the extraced concentration can be quantified.

• Journal of Soil and Groundwater Environment
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• v.20 no.2
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• pp.41-46
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• 2015

The drag of the excess charge in an electrical double layer at the solid fluid interface due to water flow induces the streaming current, i.e., the streaming potential (SP). Here we introduce a sandbox experiment to study this hydroelectric coupling in case of a tracer test. An acrylic tank was filled up with homogeneous sand as a sand aquifer, and the upstream and downstream reservoirs were connected to the sand aquifer to control the hydraulic gradient. Under a steady-state water flow condition, a tracer test was performed in the sandbox with the help of peristaltic pump, and tracer samples were collected from the same interval of five screened wells in the sandbox. During the tracer test, SP signals resulting from the distribution of 20 nonpolarizable electrodes were measured at the top of the tank by a multichannel meter. The results showed that there were changes in the observed SP after injection of tracer, which indicated that the SP was likely to be related to the solute transport.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.3
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• pp.231-241
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• 1997

A tracer model was applied in the Far East Asia to investigate the dry deposition rates of air pollutants on Korean Peninsula originated from different countries including China and Japan. Wind direction was chosen to predict the maximum deposition rates and SO$_2$ was chosen as a tracer to estimate the source strength. Model simulation shows that inflow, deposition and airborne ratios of China-originated SO$_2$ were 50%, 8% and 30%, respectively, at most. Also it was found that deposition, outbounded and airborne ratios of Korea-originated SO$_2$ were 15~77%, 8~75%, and 3~30%, respectively Model simulation also shows that inflow, deposition and airborne ratios of Kyushu-originated SO$_2$ were, 30~45%, 8~14％ and 20~25%, respectively. This study shows that tracer model can be applied on the estimation of air pollutants partitioning in regional scale and that more sophisticated modules and schemes can be developed and applied to better predict the transboundary amounts of air pollutants in this region.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.799-802
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• 2008

General behaviors based on hydraulic characteristics of natural streams and channels have been recently analyzed and developed via various numerical models. However in the states of natural hydraulics, an experimental research must be performed simultaneously with the mathematical analysis due to effects of hydraulic properties such as meander, sediment, and so on. In this study based on 2-D advection-dispersion equation, flow and tracer experiments were performed in the S-curved meandering laboratory channel with a rectangular cross-section. The channel was equipped with instrument carriages which was equipped with an auto-traversing system to be used with velocity measuring sensors throughout the depth and breadth of the flow field. To measure concentration distribution of the salt solution was adjusted to that of the flume water by adding methanol and a red dye (KMnO4) was added to aid the visualization of the tracer cloud, the tracer was instantaneously injected into the flow as a full-depth vertical line source by the instantaneous injector and the initial concentration of the tracer was 100,000 mg/l. The secondary current as well as the primary flow pattern was analyzed to investigate the flow distribution in the meandering channels. The velocity distribution of the primary flow for all cases skewed toward the inner bank at the first bend, and was almost symmetric at the crossovers, and then shifted toward the inner bank again at the next alternating bend. Thus, one can clearly notice that the maximum velocity occurs taking the shortest course along the channel, irrespective of the flow conditions. The result of the tracer tests shows that pollutant clouds are spreading following the maximum velocity lines in each cases with various mixing patterns like superposition, separation, and stagnation of pollutant clouds. Flow characteristics in each cases performed in this study can be compared with tracer dispersion characteristics with using evaluation of longitudinal and transverse dispersion coefficients(LDC, TDC). As expected, LDC and TDC in meandering parts have been evaluated with increasing distribution and straight parts have effected to evaluate minimum of LDC and TDC due to symmetric flow patterns and attenuations of secondary flow.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.187-190
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• 2001

This study is concerned with the hydrodispersive characteristics of granite in Changwon area. A single-well injection/recovery tracer test was conducted to determine longitudinal dispersivity of the granite, using sodium chloride tracer The dispersivity values obtained from the injection phase are 0.48 m (for between PW-1 and OW-3) and 0.72 m (for between PW-1 and OW-4). That obtained from the recovery phase is 0.68 m. The result of the tracer test indicates that the anisotropy and heterogeneity of the granite and the direction of flow.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.244-251
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• 2010

CSD is Active RFID based Container Security Device which is proposed by the U.S Department of Home Security. It is mounted inside the container to sense opening of the container door. ConTracer is the CSD which is developed in this research whose major features are sensing door opening status as well as history inquiring on internal environment and shock to the container by mounting the temperature/humidity/shock sensors. Moreover, its RFID frequency bandwidth uses 433MHz and 2.4GHz to correspond actively to the radio regulations used by different countries. This paper introduces the development trend of CSD, compares the ConTracer which is developed thru this research and other company's CSD, and introduces CSD System which is designed and established using ConTracer. Finally, the implemented CSD System is verified by applying the demonstration service to container distribution between Korea and China.

• The Journal of Engineering Geology
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• v.14 no.3 s.40
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• pp.301-311
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• 2004

This study is suggested a new dielectric tracer test method to understand geological structure of porous media and groundwater flow to use the dielectric constant which is one of electrical special quality of various geological materials. To measure their parameters, tracer material is made an ethanol mixing liquid(EML) having a same specific gravity of water. Also, soil materials are prepared a dielectric tracer test using the FDR system that could measure dielectric constant for saturated standard sand and river sand layers which have different initial porosity. To compare with their results, we discussed with the concentration variation of saline water having a saline concentration $3\%$ which is general tracer material by using the electro multi-meter system in the laboratory or field test. In two tracer experiment results, EML tracer test could confirm definitely EML concentration variation from each saturated soil layer as standard and river sands. However, tracer test of saline water $3\%$ concentration could not confirm permeating movement of water by degree of salinity change because these are settled at lower part column in a whole column area continuously. These causes are that specific gravity of saline water is heavier than water. That is, it could know that deposition of saline water is composed of lower part of soil column continuously independently of the direction of water into saturated soil material.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.230-236
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• 1998

Thermal environment of greenhouse was investigated by thermo-tracer in this study. The Thermo-tracer is a high-sensitivity infrared thermometer of non-contact type. The infrared energy emitted from the measured object is converted into an electrical signal by the detector(HgCdTe) and display as a color or black & white thermal image by way of optical scanning, The experiment was conducted for Venlo-type greenhouse with pad & fan system. The temperature difference between measured by Thermo-trace and measured by HOBO sensor is maximum 0.8$^{\circ}C$. Thermo-trace is possible to use for the thermal environment analysis and diagnosis of a cooling and heating system of greenhouse.