• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.322-325
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• 2003

The feasibility of treating 2-chlorophenol (2CP) contaminated soils with ozone venting was investigated in this research. Adding ozone to the existing air-venting process provides an alternative to achieve a complete in-situ treatment by oxidizing the contaminant in the process. A column study with artificial soil was used to simulate the venting process. Ozone concentrations at 2.4, 7.6 and 19.4 mg/L, and flow rates at 100 and 150 mL/min were used. The reaction times were 10, 20, 50, and 60 minutes. Blank samples using air venting were also run for comparison. It is obvious that ozone-venting had a much faster removal rate than air-venting. As higher concentration of ozone is applied, the reaction rate increased significantly. As higher concentration was applied, the flux of ozone to the liquid film increased. This also increased the removal rate of 2CP and therefore the breakthrough curve came out earlier.

• Elastomers and Composites
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• 제51권4호
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• pp.263-268
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• 2016

In the polymer shaping process that uses molds, the quality of the molded products is determined not only by the flow of the (molten) polymer but also by the air venting in the cavity. Inadequate air venting in the cavity can cause defects in the product, such as voids, short shot, or black streaks. As it is critical to consider the location and size of the vents for proper venting of the air in the cavity, a method that predicts the flow of air and material is required. The venting of air by the flow of rubber inside the cavity was simulated by using a multi-phase computational fluid dynamics method. Through computer simulation, the interface of rubber and air over time was predicted. Then, the velocity and pressure distribution of the venting air were observed. Our research proposes a fundamental method for analyzing the multi-phase flow of polymer materials and air inside the cavity of a mold.

• 한국토양환경학회지
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• 제3권2호
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• pp.53-60
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• 1998

주요 토양 및 지하수 오염물질인 가솔린에 대해 순수한 액상으로 존재할 경우와 오염된 토양으로 존재할 경우 물에 대한 용해거동을 각각 살펴보았다. 특히 휘발에 의한 가솔린 성분조성의 변화가 용출거동에 미치는 영향을 살펴보았다. 가솔린 오염토양을 공기흐름으로 통기시켰을 때 토양 중 용출거동의 변화는 공기 중 휘발농도의 변화양상과 비슷하게 나타나며 그 경향은 두 가지로 요약될 수 있다. 첫째 총량으로서의 가솔린 농도(TPH-GRO)는 휘발이 진행됨에 따라 급격히 감소하다가 75%정도의 무게감소 이후 점차적으로 감소하는 경향을 보이고 있다. 둘째 가솔린 개별성분의 농도는 일반적으로 증가하다가 감소하는 경향을 보이는데 분자량이 높을수록 상대적인 농도증가폭이 크고 최고농도에 도달하는데 많은 시간이 걸렸다. 한가지 특이한 점은 휘발이 진행될수록 공기 중 가솔린 농도가 용출 농도보다 훨씬 빠르게 감소한다는 점이다. 이것은 휘발에 의해 상당량의 가솔린이 제거되었을 경우 잔류가솔린으로 인한 위해성의 초점은 인근 대기오염보다도 지하수 오염에 맞추어져야 함을 시사한다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.225-231
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• 1998

Open dump causes groundwater and soil contamination by leachate, air pollution by LFG (Landfill Gas). In this paper, in order to improve landfill researches which have been done about reduction of high leachate level and LFG collection in the Kimpo landfill separately, the effect of simultaneous flowing of leachate and LFG has been Studied. The HYLGS (Hanyang Leachate Gas Simulator) used in this study is a 3D, 2-phase, transient FDM model which can be applied to venting trenches in a landfill. From present numerical analysis it can be concluded that all the pressures of the Kimpo landfill grid system are almost the same and their maximum value in the center grid block of the system is approximately 26 m $H_2O$ (2.52 atm), that because the pressures of venting trench layer situated in the middle of the landfill have the lowest values and equal with air pressure, the venting trenches play an important role in landfill stabilization, that the flow of gas will be more difficult as time goes by owing to the increase of LGR(Leachate and gas ratio).

• 한국태양에너지학회 논문집
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• 제32권6호
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• pp.76-84
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• 2012

This study conducted experiments to measure air currents in an experimental building according to external conditions, types of induction ducts, and types of internal sockets by applying an external induction duct comprised of inducing openings and lines and induction units to the kitchen and bathroom vents at the rooftop of a super high-rise apartment building in order to help to improve the venting performance. The study also proposed the optimization of the external induction-style kitchen and bathroom vents capable of wind power generation. (1) As for air current distribution according to vent velocity changes, it increased the venting performance of the kitchen and bathroom by 1.0m/s at vent velocity of 2.0m/s or higher and allowed for wind power generation. (2)As for air current distribution according to external velocity changes, it increased the venting performance of the kitchen and bathroom by 1.2m/s at external velocity of 2.0m/s or higher and allowed for wind power generation. (3)As for air current distribution according to wind direction changes($0{\sim}180^{\circ}$), it was favorable for higher vent velocity when the angle between the external induction duct direction and prevailing wind direction was within ${\pm}30^{\circ}$. (4)As for air current distribution according to induction duct type, the[M1] type combining the inducing openings and lines with the induction units recorded the highest improvement effects in the kitchen and bathroom venting performance by increasing vent velocity by 46%. (5)As for air current distribution according to the changing types of internal sockets where the main ducts of the kitchen and bathroom are connected to the external induction ducts, the venturi tube type[Sv] increased vent velocity by 66% based on the smoothest external inflow.

• Advances in aircraft and spacecraft science
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• 제3권1호
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• pp.77-93
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• 2016

In this paper, a zero-dimensional mathematical formulation for rapid and explosive decompression analyses of pressurized aircraft is developed. Air flows between two compartments and between the damaged compartment and external ambient are modeled by assuming an adiabatic, reversible transformation. Both supercritical and subcritical decompressions are considered, and the attention focuses on intercompartment venting systems. In particular, passive and active vents are addressed, and mathematical models of both swinging and translational blowout panels are provided. A numerical procedure based on an explicit Euler integration scheme is also discussed for multi-compartment aircraft analysis. Various numerical solutions are presented, which highlight the importance of considering the opening dynamics of blowout panels. The comparisons with the results from the literature demonstrate the validity of the proposed methodology, which can be also applied, with no lack of accuracy, to the decompression analysis of spacecraft.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3310-3316
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• 2022

Owing to the rising concerns about the safety of nuclear power plants (NPP), it is essential to study the venturi scrubber in detail, which is a key component of the filtered containment venting system (FCVS). FCVS alleviates the pressurein containment byfiltering and venting out the contaminated air. Themain objective of this research was to perform a CFD investigation of different configurations of a circular, non-submerged, self-priming venturi scrubber to estimate and improve the performance in the removal of elemental iodine from the air. For benchmarking, a mass transfer model which is based on two-film theory was selected and validated by experimental data where an alkaline solution was considered as the scrubbing solution. This mass transfer model was modified and implemented on a unique formation of two self-priming venturi scrubbers in series. Euler-Euler method was used for two-phase modeling and the realizable K-ε model was used for capturing the turbulence. The obtained results showed a remarkable improvement in the removal of radioactive iodine from the air using a series combination of venturi scrubbers. The removal efficiency was improved at every single data point.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 추계학술발표회요약집
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• pp.142-142
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• 1998

• 설비공학논문집
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• 제21권12호
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• pp.703-714
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• 2009

One of the biggest problems in smoke control systems for high-rise buildings is stack effect, but there are no recognized methods or measures to solve the problem of stack effect as yet. The stack effect can be overcome by forming the uprising current inside the stair hall properly, but there is a limit to the height in supplying into the stair hall the smoke control air volume to be supplied to a floor in case of escape from fire. The limit to the height can be extended by over-coming the stack effect by pressurizing the stair hall and the ancillary room simultaneously. It can also be anticipated that the stack effect can be overcome by connecting the air supply shaft to the stair hall at the top. As a result of computer simulations using a network type of tool, it is found that adequate performance can be achieved by pressurizing the stair hall only for a building of 190m or less, and up to 360m when pressurizing the stair hall and the ancillary room simultaneously. In all those cases, however, an overpressure venting damper is required which operates within a suitable range for venting the overpressure outside.

• 한국환경보건학회지
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• 제32권5호
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• pp.499-505
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• 2006

Bioventing efficiency was compared in a continuous and an intermittent(6hr injection and 6hr rest) air injection mode. Two lab-scale columns which packed with 5 kg of soil artificially contaminated by diesel oil were operated. The columns were maintained at the $25^{\circ}C{\pm}2.5$ in order to minimize the effect of exterior temperature variation. The flow rate of air injection mode were maintained constantly at the flow rate of 10 ml/min. The moisture of the columns was stably maintained at $60{\sim}80%$ of field capacity. The nutrient compounds were added to make C:N:P ratio as 100:10:l. The continuous and intermittent injection modes showed 67.56% and 69.63% reduction of initial TPH concentration during 90 days, respectively. Two venting modes showed similar results in the analysis of the trends of the hydrocarbon utilizing bacterial counts for operating periods. The carbon dioxide production rate of the continuous injection mode was higher than that of intermittent injection mode. The loss of diesel oil by volatilization in the continuous and intermittent injection modes were about 5% and 1%, respectively. The lower volatilization loss in the intermittent injection mode suggested that the biodegradation of TPH in the intermittent injection mode was greater than that of the continuous mode. These results suggested that the intermittent injection mode is more efficient than the continuous venting mode.