• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.304-307
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• 1995

In this paper, an optical sensing system has been developed to detect the dust in vacuum cleaner. The system works well through self-tuning mechanism, even though there are systemic variance and characteristic change which is caused by the pollution on the surface of the optical elements. Using the developed sensing system, a novel suction power control system has been proposed, which is able to be used for a long time.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.290-297
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• 2016

도시철도 터널내에 축적된 미세먼지(PM10 and PM2.5)의 제거를 위해 사용되는 분진흡입차량의 성능은 하부흡입시스템의 설계방법에 따라 성능이 달라진다. 본 논문에서는 터널집진차량의 하부에 설치된 먼지흡입시스템의 고효율화를 위하여 궤도의 바닥면에 쌓인 먼지를 비산시키는 압축공기 블로어와 먼지 흡입구를 동시에 가지는 모듈화된 먼지흡입구조를 제안하였다. 흡입과 블로어의 상반된 구조를 동시에 가진 흡입시스템의 먼지유동 최적화를 위해 난류유동에 기초한 수치해석을 수행하였다. 해석결과로 먼지흡입효율을 최대화 할 수 있는 공기 블로어의 설치각이 $6^{\circ}$ 내외에서 결정되고, 이를 적용하면 5 km/h의 청소속도를 가지는 분진흡입차량의 흡입효율을 10%이상 높일 수 있음을 확인하였다.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2195-2201
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• 2009

본 논문은 R290, R600a, R1270과 같은 탄화수소계 냉매를 사용하는 냉동사이클의 효율에 대한 흡입관 열교환기의 영향을 고려하였다. 이러한 흡입관 열교환기는 냉동시스템의 성능을 향상시킬 수도 있지만, 성능을 저하시킬 수도 있다. 본 논문에서는 흡입관 열교환기를 가진 냉동사이클의 성능 특성을 파악하기 위해서 정상상태의 수학적 모델을 사용하였다. 그리고 탄화수소계 냉매유량, 흡입관 열교환기의 내관 직경, 길이, 유용도 등과 같은 운전조건의 영향을 분석하였다. 연구결과는 흡입관 열교환기의 내관 직경, 길이, 유용도, 탄화수소계 냉매의 질량유량은 냉동사이클의 상대냉동능력지수, 냉동능력, 압축일량에 영향을 미치는 것을 알 수 있었다. 따라서 이러한 영향을 상세히 파악하여, 흡입관 열교환기를 설치한 탄화수소계 냉매용 증기압축식 냉동사이클을 설계할 필요가 있다.

• Nuclear Engineering and Technology
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• 제53권3호
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• pp.1041-1048
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• 2021

An engineered barrier system (EBS) for the disposal of high-level radioactive waste (HLW) is composed of a disposal canister with spent fuel, a buffer material, a gap-filling material, and a backfill material. As the buffer is located in the empty space between the disposal canisters and the surrounding rock mass, it prevents the inflow of groundwater and retards the spill of radionuclides from the disposal canister. Due to the fact that the buffer gradually becomes saturated over a long time period, it is especially important to investigate its thermal-hydro-mechanical-chemical (THMC) properties considering variations of saturated condition. Therefore, this paper suggests a new method of measuring thermal conductivity and water suction for single compacted bentonite at various levels of saturation. This paper also highlights a convenient method of saturating compacted bentonite. The proposed method was verified with a previous method by comparing thermal conductivity and water suction with respect to water content. The relative error between the thermal conductivity and water suction values obtained through the proposed method and the previous method was determined as within 5% for compacted bentonite with a given water content.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.1-6
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• 2023

In CO₂ laser surface machining of plastic films in modern display manufacturing, scattering of fume particles could be a major source of well-recognized film surface contamination. This computational fluid dynamics research investigates the suction air flow patterns over a film surface as well as the dispersion of micron-sized fume particles with low-Reynolds number particle drag model. The numerical results show the recirculatory flow patterns near laser machining point on film surface and also over the surface of vertical suction slot, which may hinder the efficient removal of fume particles from film surface. The dispersion characteristics of fume particles with various particle size have been tested systematically under different levels of suction flow intensity. It is found that suction removal efficiency of fume particles heavily depends on the particle size in highly nonlinear manners and a higher degree of suction does not always results in more efficient particle removal.

• 한국산학기술학회논문지
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• 제18권3호
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• pp.115-121
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• 2017

도시철도 터널 내에 축적된 미세먼지(PM10 and PM2.5)의 제거를 위해 사용되는 분진흡입차량은 에어 블로어와 흡입시스템으로 구성된 하부흡입시스템의 설계방법에 따라 성능이 달라진다. 본 논문에서는 터널 집진차량의 하부에 설치된 먼지 흡입시스템의 효율 향상을 위하여 흡입구와 에어 블로어에 코안다 효과를 이용한 유속 조절장치를 적용하여 그 효과를 확인하였다. 특히, 공기 유동에 대한 수치해석을 통하여 진공 흡입구 내에 코안다 효과를 이용한 유속조절장치를 적용하였으며, 유속 조절각이 약 90도 내외일 때 유속의 상승과 더불어 유동의 안정화가 동시에 이루어질 수 있음을 확인하였다. 또한 링 블로어에 의해 동작되는 에어 나이프형 공기 블로어는 양쪽 끝 가장자리에 코안다 효과를 유도할 수 있는 엣지 구조를 삽입함으로써 블로어 양 끝단의 유속 저하를 개선할 수 있음을 확인하였다. 이러한 4개의 통합된 모듈 형식의 흡입 시스템의 설계는 최적화를 통하여 바닥 먼지가 비산됨과 동시에 흡입구로 흡입되어 궤도면에 누적된 미세먼지와 초미세먼지의 제거에 효과적으로 활용될 수 있을 것으로 기대된다.

• International Journal of Air-Conditioning and Refrigeration
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• 제6권
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• pp.148-157
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• 1998

This study presents test results of a residential window air-conditioner using R22 and two potential alternative refrigerants, R407C and R410B. A series of performance tests has been carried out for the basic and liquid-suction heat exchange cycles in a psychometric calorimeter test facility. For R407C, the same rotary compressor was used as in the R22 system. However, compressor for the R410B system was modified to provide the similar cooling capacity. The evaporator circuit was changed to get a counter-cross flow heat exchanger to take advantage of zeotropic mixture's temperature glide, and liquid-suction heat exchange cycle was also considered to improve the system performance. Test results were compared with those for the basic R22 system. The modified system with a liquid-suction heat exchanger increased cooling capacity and energy efficiency by up to 5%.

• 신재생에너지
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• 제6권3호
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• pp.47-54
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• 2010

Foundation plays an important role in the offshore wind turbine system. Different from conventional foundations, the suction caisson is proven to be economical and reliable. In this work, three-dimensional finite element method is used to check the suitability of suction caisson foundation. NREL 5MW wind turbine is chosen as a baseline model in our simulation. The maximum overturning moment and vertical load at the mudline are calculated using FAST and Bladed. Meanwhile the soil-structure interaction response from our simulation is also compared with the experiment data from Oxford university. The design parameter such as caisson length, diameter of skirt and spacing of multipod are investigated. Accordingly based on these parameters suggestions are given to use suction caisson foundations more efficiently.

• Geomechanics and Engineering
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• 제25권4호
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• pp.283-294
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• 2021

This paper presents a rigorous solution for spherical cavity expansion in unsaturated soils under constant suction condition. The hydraulic behavior that describes the saturation-suction relationship is modeled by a void ratio-dependent soil-water characteristic curve, which allows the hydraulic behavior to fully couple with the mechanical behavior that is described by an extended critical state soil model for unsaturated soil through the specific volume. Considering the boundary condition and introducing an auxiliary coordinate, the problem is formulated to a system of first-order differential equations with three principal stress components and suction as basic unknowns, which is solved as an initial value problem. Parameter analyses are conducted to investigate the effects of suction and the overconsolidation ratio on the overall expansion responses, including the pressure-expansion response, the distribution of the stress components around the cavity, and the stress path of the soil during cavity expansion. The results reveal that the expansion pressures and the distribution of the stress components in unsaturated soils are generally higher than those in saturated soils due to the existence of suction.

• 대한간호학회지
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• 제41권2호
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• pp.175-181
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• 2011

Purpose: This study was conducted to identify endotracheal colonization and the incidence of ventilator-associated pneumonia related to the type of endotracheal suction system. Methods: The participants in this study were ICU patients hospitalized between October 2009 to March 2010 who used ventilators for over 48 hr with closed (CSS, n=30) or open (OSS, n=32) suction systems. To standardize the pre-intervention suction system, a suctioning protocol was taught to the ICU nurses. Collected data were analyzed using ${\chi}^2$-test, Fisher's exact test, Wilcoxon rank sums test, Wilcoxon test, Log-rank test and Poisson regression. Results: Endotracheal colonization was higher in OSS than CSS from day 1 to day 8 while using a ventilator and there was a significant difference between the two groups. The CSS reached 50% of endotracheal colonization by the 4th day, whereas for the OSS, it was the 2nd day (p=.04). The incidence of ventilator-associated pneumonia showed no significant difference. Conclusion: For patients with a high risk of pneumonia, CSS must be used to lower endotracheal colonization.