• 한국환경복원기술학회지
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• 제14권5호
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• pp.69-79
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• 2011

This study assessed the subsurface runoff and peak flow reduction in rain gardens. The results showed that the highest water retention was found in rain garden mesocosms in which Rhododendron lateritium and Zoysia japonica were planted, followed by mesocosms in which either R. lateritium or Z. japonica was planted, and the lowest water retention rate was found in non-vegetated control treatment mesocosms(${\alpha}$ < 0.05). Although higher rainfall intensity caused a decrease of peak flow reduction in both vegetated and non-vegetated treatments, peak flow reduction was the greatest in mesocosms with mixed plants. A rain garden can be an effective tool for environment-friendly stormwater management and improving ecological functions in urban areas. Depending on the purpose such as delaying runoff or increasing infiltration, various plant types should be considered for rain garden designing.

• 한국소음진동공학회논문집
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• 제15권4호
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• pp.452-456
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• 2005

Cyclone is widely adopted in the vacuum cleaner, because of the simple structure, the high dust collection efficiency and its transparency feature, which can be shown to the customer. At past times, cyclone performance was represented by collection efficiency, flow rate, pressure drop etc. At recent times the noise problem is getting important as cyclone comes into home-appliances. In this paper, pressure drop of cyclone and it's noise were measured at the variation of the cyclone structure and the main sources of cyclone peak noise was found by experimental and numerical analysis. In addition, the structure for peak noise reduction was suggested and it is beneficial both pressure drop and noise reduction.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.89-92
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• 2004

Cyclone is widely apoted in the vacuum cleaner, because of it's simple structure, the dust collection efficiency is high and its transparency feaure which can be shown to the customer. At past times, cyclone performance is represented by collection efficiency, flow rate, pressure drop etc. At recent times the noise problem is getting important as cyclone comes into home-appliances. In this paper, cyclone's pressure drop and noise is measured at the variation of the cyclone structure and the main sources of cyclone peak noise is found by experiments and numerical analysis. In addition, the structure for peak noise reduction is suggested and it is beneficial both pressure drop and noise reduction.

• 한국환경과학회지
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• 제4권1호
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• pp.91-103
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• 1995

The reaction rate, equilibrium, and flow injection analysis methods were fundamentally evaluated for the determination of aqueous ammonia. The selected indophenol blue method was based on the formation of indophenol blue in which ammonium ion reacted with hypochlorite and phenol in alkaline solution. In the optimized reaction condition, the reaction followed 1st order reaction kinetics and the final product was stable. The absorbance measurements before and after the equilibrium were utilized for the reaction rate and equilibrium methods. The reaction rate methods, based on the relative analytical signals for the possibility of eliminating interferents, were shown to have good linear calibration curves but the detection limit and the calibration sensitivity were poorer than those in the equilibrium method. The detection limits were 32-49 pub and 24 pub for the reaction rate and equilibrium methods, respectively In the flow injection analysis, the absorbance was measured before the equilibrium reached and thus resulted in 30% reduction of calibration sensitivity. However, the detection limit was 11 ppb, indicating that the peak-to-peak noise for the blank was remarkably improved. Compared to the manual methods, the optimized experimental condition in a closed reaction system reduced the blank absorbance and the inclusion of ammonia from the atmosphere was prevented. In addition, highly reproducible mixing of sample and reagents and analytical data extracted from continuous recording showed excellent reproducibility.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.628-631
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• 2007

One of the structural measures for the peak flow reduction is infiltration facilities. There are many types in infiltration facilities - infiltration basin, trench, bed, porous pavement, percolated subdrain, dry well. In this study runoff reduction effect of infiltration trench is analyzed by WinSLAMM. Runoff reduction effect is investigated by each design rainfall and temporal pattern of rainfall particularly. The biggest reduction is shown in Yen and Chow's temporal pattern of design rainfall and the smallest reduction is shown in Huff's first quartile pattern. Runoff reduction rate is presented about 6 to 14 percentage, and the larger return period, the smaller runoff reduction rate.

• 한국수자원학회논문집
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• 제45권1호
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• pp.65-73
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• 2012

기후변화로 인한 집중호우와 도시화로 인한 불투수면의 증가는 많은 양의 비를 바로 하수관거로 유출시켜 관거 용량초과로 저지대침수 등의 피해를 일으킨다. 지금까지는 도시의 치수안전도를 높이기 위해 하수관거를 확장하고, 빗물펌프장의 용량을 증대하는 등의 방법을 주로 채택하고 있지만 많은 비용과 시간의 소비를 필요로 하여 현실적으로 불가능에 가깝다. 최근 소방방재청과 수원시는 기존 우수배수 시스템의 한계를 보완하고 대처하기 위한 새로운 대처방안으로 다목적 분산형 빗물관리를 제안하고 있다. 본 연구에서는 수원의 상습침수지역인 M마을을 연구 대상지로하여 XP-SWMM을 이용하여 분산형 빗물저류조 적용에 따른 첨두유출 저감 효과를 확인을 위해 설치 개수, 배치유형(설치위치)을 다르게 하여 집중호우시 치수 안전도에 미치는 영향을 모의하였다. 그 결과 3,000 용량의 빗물저류조 한 개를 설치할 경우 첨두유출이 15.5% 저감되었으며, 500$m^3$ 용량저류조를 6개설치하였을 때는첨두유출이 28%저감되었다. 빗물저류조 배치유형의경우 상류 지역에 가장 비중 있게 설치하고 중류, 하류 순으로 비중을 두어 설치한 형태가 가장 첨두유출 저감효과가 좋았다. 본 연구에서 얻어진 다목적 분산형 빗물관리 시스템의 해석방법은 기후변화에 대비하여 하수관거 용량을 증설하지 않고도 치수 안전도를 증가시킬 수 있는 시스템을 경제적으로 설계하고, 그 효과를 예측하는데 사용될 수 있다.

• 한국농공학회논문집
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• 제58권6호
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• pp.93-100
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• 2016

This study conducted a quantitative assessment on the environmental flows associated with climate change in the Gosam Reservoir, Korea. The application of RCP 8.5 climate change scenario has found that the peak value of High Flow Pulses has increased by 36.0 % on average compared to historical data (2001 ~ 2010), which is likely to cause disadvantage on flood control and management but the increase in peak value is expected to make a positive impact on resolving the issue of green algal blooms, promoting vegetation in surrounding areas and encouraging spawning and providing habitats for native species by releasing a larger amount of landslides as well as organic matters than the past. However, the decreasing pattern of the peak value of High Flow Pulses is quite apparent with the trend of delay on the occurrence time of peak value, necessitating a long-term impact analysis. The peak value of Large Floods shows a clear sign of decrease against climate change scenario, which is expected to lead to changes in fish species caused by degraded quality of water and decreasing habitats. A quicker occurrence of Small Floods is also expected to make an impact on the growth cycle of aquatic plants, and the reduction in occurrence frequency of Extreme Low Flows is to contribute to increasing the population of and raising the survival rate of native fish, greatly improving the aquatic ecosystem. The results of this study are expected to be useful to establish the water environment and ecological system in adapting or responding to climate change.

• 한국자동차공학회논문집
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• 제3권6호
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• pp.41-54
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• 1995

A mathematical model for wall-flow monolith ceramic diesel particulate filter was developed in order to describe the processes which take place in the filter during regeneration. The major output of the model comprises ceramic wall temperature and regeneration time(soot reduction). Various numerical tests were performed to demonstrate how the gas oxygen concentration, flow rate and the initial particulate trap loading affect the regeneration time and peak trap temperature. The model is shown to b in reasonable agreement with the published experimental results. This model can be applied to predict the thermal shock failure due to high temperature during combustion regeneration process.

• 한국전통조경학회지
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• 제35권4호
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• pp.126-133
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• 2017

본 연구는 조경기술기반 LID 시스템 적용에 따른 선릉 정릉 권역의 우수유출변화를 수문학적 관점에서 분석하였으며, 연구결과를 다음과 같이 정리할 수 있다. 첫째, 광화문 침수가 발생한 2011년 7월 27일 기준 최대순간강우량은 27일 10시에 기록된 183mm/hr로 시간당 최대강우량 57.5mm/hr에 비해 3배 이상의 강우강도가 10분간 집중된 것으로 확인되었다. 둘째, 토심기준 시나리오에서 담심 1,500mm의 경우 첨두유출량 제어가 가능하여 해당 조경기술기반 LID 시스템 적용 시 선릉 정릉 권역의 수해취약성을 개선할 수 있을 것으로 판단된다. 셋째, 담심 기준 시나리오에서 모든 토심 모형에서 첨두유출량 제어가 이루어지지 않았으나, 최초 우수유출을 토심 기준 시나리오에 비해 4시간 10분의 추가적인 지연효과를 기록하였다. 초기 우수유출저감에는 토심, 첨두유출량에는 담심이 상대적으로 중요한 지표로 해석되었다. 이를 통해 문화재 보호권역 내 경관친화적인 생태적 요소를 시스템화하여 적용할 경우 예상되는 수해방재효과를 이론적으로 확인할 수 있었다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.213-216
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• 2006

This paper was a study about noise reduction through flow stabilization in duct using experimental method and numerical analysis at the same time. To determine the fan's type three kinds of fans(axial fan, centrifugal fan, and axial fan with centrifugal type blades) was examined to investigate the suitability for in-line duct. As a result, under the equal number of rotation 2000 RPM, performance of an axial fan with centrifugal type blades was the most superior by 55dBA at 4.3CMM among other fans. After this, analyzed the results of the numerical analysis to find out the optimum design of pitch angle such as $0^{\circ}$, $10^{\circ}$, $15^{\circ}$ and $20^{\circ}$. The intensity of turbulence was low when pitch angle was $15^{\circ}$ and air volume became peak by 5.08 CMM. It was observed that axis component of velocity increased gradually when pitch angle increased from $0^{\circ}$ to $20^{\circ}$, and embodied noise reduction and improvement of air flow rate through flow stabilization.