• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.20-28
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• 2006

Partitioning tracer tests were conducted to quantify the saturation degree of diesel and water in unsaturated soil, respectively. The use of partitioning tracers that partition into diesel, water, and air (i.e., three-phase partitioning), is in attractive alternative to traditional coring and analysis method. These gaseous partition tracers not global warming gas like CFC's are Butane, Acetylene, Ethylene, Methylene chloride, and Methane. The glass column packed with sandy soil was prepared, in which a three-phase system of air, water, and diesel was maintained. Conservative and partition gas tracers were injected into the columns and detected easily using a single GC detector(FID). For each tracer, a method of moments was used to estimate partition coefficient between water, diesel. and the air, respectively. The results from the column studies showed that the diesel/air tracer partition coefficient ranged from 8.2 to 868 and 9.2 for water/air. Saturation degree of diesel and water in the column, predicted by the partition coefficients obtained from tests, was underestimated up to 66% and 23% respectively.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.570-577
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• 2000

In this study, using modified tracer method(Constant Rate Injection, CRI method), reaeration rates were measured in the territories of Bokha stream. In case of Kwanri stream, reaeration rates of a diversion were measured simultaneously. Propane gas and Rhodamine-WT were used as gas and dye tracer, respectively. The experimental results show that reaeration rates of the stream were ranged from 6.16 to 24.52 1/day and those of a diversion in Kwanri stream were ranged from 28.39 to 123.61 1/day. It is resulted that mean velocity of stream is a dominant factor in reaeration process and diversion significantly influence on reareation process.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.1-9
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• 2000

To understand the thermal characteristics around the piston ring gap ring gap positions and piston temperatures are measured simultaneously. The locations of piston ring gap are measured by the radio-tracer method and piston temperature are measured by a K-type thermocouple and scissors type linkage system. From these experiments following facts are clarified. Piston temperatures fluctuate according to the piston ring rotation. And the temperature fluctuation is mainly affected by top ring gap position irrelevant to the second ring fop position. If the top ring gap position increases and the temperature of top ring groove shows maximum value when top rin gap position coincide with temperature measuring point. The maximum amplitude of temperature fluctuation which is proportional to the blow by gas rate is around 12-15$^{\circ}C$.

• Journal of the Korean Institute of Educational Facilities
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• v.11 no.2
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• pp.17-23
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• 2004

The purpose of this study concerns the improvement of air quality in school classrooms. Polluted indoor air is improved by efficient ventilation systems. So it is important to measure the amount of ventilation needed in classrooms. First, the amount of natural ventilation were measured through a tracer gas method. And we have established a heat recovery ventilation system from 4 cases of airflow in classrooms, and we have measured the change of $CO_2$ density. According to air quality measurements in the classrooms, the density of $CO_2$ is well above environmental standards which are acceptable. When the amount of ventilated airflow increases, indoor air quality is improved. It is surveyed that the most suitable amount of external inducted air is 770 CMH to satisfy $CO_2$ less than 1,000 ppm in classrooms. For improvement of air quality in classrooms, we must consider a suitable ventilation plan and installation of ventilation systems when constructing school buildings.

• Journal of the Korean Society of Visualization
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• v.2 no.1
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• pp.39-45
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• 2004

A time-resolved two-phase PIV system using a single camera has been developed, which introduces a method of image separation into respective phase images, and is applied to freely rising single bubble. Gas bubble, tracer particle and background have different gray intensity ranges on the same image frame when reflection and dispersion in the phase interface are intrinsically eliminated by optical filters and fluorescent particles. Further, the signals of the two phases do not interfere with each other. Gas phase velocities are obtained from the separated bubble image by applying the two-frame PTV. On the other hand, liquid phase velocities are obtained from the tracer particle image by applying the cross-correlation algorithm. As a result, the bubble rises rectilinearly just after it is released from an injector and then has a zigzag motion in the far field. From the trajectory of the bubble, it is found that the period of the zigzag motion is closely related to the vortex shedding although the wavelength of it varies along its movement.

• Journal of the Korean Institute of Gas
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• v.16 no.2
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• pp.31-37
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• 2012

This paper describes to analyze the ventilation performance of a room air conditioner for indoor comfort control. An experimental apparatus consists of a test room, the room air conditioner, a tracer gas measurement system, a supply fan and a controller. Ventilation performance as a function of human occupancy is evaluated with supply ventilation air using a tracer gas technique of CO2 gas in the test room. The ventilation performance is evaluated in a step-down method based on ASTM Standard E741-83 and is found to increase with increasing supply ventilation rate. The CO2 gas concentration is decayed rapidly without human occupancy. The ventilation performance without human occupancy increases up to 55% and the ventilation performance with one person increases up to 25% at the supply air of 570 lpm comparing with a natural reduction after one hour. A modeling for ventilation performance of a room air conditioner in a test room is presented using experimental datum.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.944-949
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• 2006

An infiltration was realized as an important part of ventilation to change fresh air with contaminated air in a house. In this study, it was measured the infiltration in new apartment buildings according to Seasons, height etc. We measured the infiltration by using tracer gas method and did for 24hours. To quantify the infiltration, Sulfur Hexafluoride($SF_6$) gas was used. The Constant Concentration was conducted during experimental process and the concentration of the gas was measured with a gas monitor. In the results of the measurement, the infiltration were appeared over 0.6 ACH in winter and about 0.2 ACH in summer and autumn. Also the infiltration were measured more highly at high and low stories than middle stories in winter.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.223-228
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• 1997

The gas dynamics in a stagnation point upflow OMVPE reactor were studied by Raman spectroscopy. The gas temperature was measured as a function of inlet gas velocity and aspect ratio for both H$_2$ and N$_2$ carrier gases. The centerline temperature gradient was latger at higher inlet velocities and with the use of N$_2$, and only weakly dependent on the aspect ratio. a tracer molecule, CH$_4$, was used to investigate the steady state behavior of reactants in the reactor, and the use of a sweeping flow was found to be a suitable method for preventing wall deposition. The transient switching response of the gas manifold was also investigated. Under certain conditions (low velocities, unmatched flows) recirculation flows were apparent. Numerical calculations of the reactor gas dynamics gave reasonable agreement with experimental results when detailed thermal boundary conditions were included.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2001.11a
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• pp.77-82
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• 2001

This paper is contents that measure the ventilation rates and temperature by driving condition of exhaust fan, vapor, contaminant occurrence amount of carbon dioxide etc. In kitchen of apartment house. The ventilation rates in the apartment kitchen measured by Tracer Gas Method. And, temperature of when cook by gas table hood lower part 10cm and floor upside 10cm of kitchen central part, 120cm, 210cm heights measure. As ventilation rates measurement result, ventilation number of times was 0.7(number of times/hour) when did not to operate exhaust fan. but we were measured by 2.3(number of times/hour) when drove strongly. As temperature measurement result at cooking by gas table, temperature showed highest in hood lower part 10cm of case that do not operate exhaust fan. Temperature at kitchen central was most low in 10cm height in talc floor, and 210cm were measured highest. Concentration of carbon dioxide is very high by 4,350ppm after measurement time 10 minutes in state who do not operate exhaust fan at cooking by gas table.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1060-1071
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• 2005

Passive gas dispersions over a 1/1000 scale terrain model at Eiffel type wind tunnel were reproduced by numerical simulation. Large eddy simulation was used to treat the sub-grid scale turbulences. The terrain features were represented by millions of point forces densely distributed over the solid surface using the virtual boundary method. The model simulations agreed very well with the experiments in a consistent fashion for all wind directions. The measured profiles of the wind speeds as well as the tracer gas concentrations were nicely simulated by the CFD model at most locations scattered over the model terrain. With scale factor adjusted and the thermal stratification effects incorporated, the CFD model was expected to provide reliable information on pollutant dispersions over the real complex terrains.