• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.468-471
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• 2005

The Air Quality Sensor(AQS), located near the fresh air inlet, serves to reduce the amount of pollution entering the vehicle cabin through the HVAC(heating, ventilating, and air conditioning) system by sending a signal to close the fresh air inlet door/ventilation flap when the vehicle enters a high pollution area. One chip sensor module which include above two sensing elements, humidity sensor and bad odor sensor was developed for AQS (air quality sensor) in automobile. With this sensor module, PIC microcontroller was designed with back propagation neural network to reduce detecting error when the motor vehicles pass through the dense fog area. The signal from neural network was modified to control the inlet of automobile and display the result or alarm the situation. One chip microcontroller, Atmega128L (ATmega Ltd., USA) was used. For the control and display. And our developed system can intelligently detect the bad odor when the motor vehicles pass through the polluted air zone such as cattle farm.

• 한국분무공학회지
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• 제6권1호
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• pp.9-17
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• 2001

The effect of air entrainment in twin-fluid spray structure is investigated experimentally by varing the amount of itemizing air. The air entrainment is expected to affect on droplet size and velocity, droplet number density, turbulent kinetic energy and vorticity. PDA(Phase Doppler Anemometer) and PIV(Particle Image Velocimetry) system are used to measure those important factors in analyzing spray structure. The results show that spray structure consists of three distinctive regions ; the atomizing region near nozzle, characterizing strong convective effect, the central core region where droplets are accelerated, and the spray sheath region where droplets are decelerated due to air entrainment. The local air entrainment rate is largest near nozzle, characterizing strong turbulent kinetic energy and vorticity but deceases along axial distance.

• 한국지반공학회논문집
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• 제31권10호
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• pp.37-47
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• 2015

최근 콘크리트의 성능 향상 및 현장 공사 품질관리 개선으로 인해 현장타설말뚝의 콘크리트 품질이 많이 향상되었지만 아직까지도 콘크리트에 대하여 기존에 보수적인 품질관리 기준을 적용하고 있다. 본 연구에서는 콘크리트 타설시 슬럼프량, 염분량, 공기량, 외기온도 등이 콘크리트 공시체 강도에 미치는 영향을 분석하였다. 이를 위해서 인천 송도지역 기초시공현장에서 6개월 이상 동안 시공된 현장타설말뚝 타설시 제작한 공시체 200개 이상의 자료를 분석하여 데이터베이스를 구축하고 통계 분석하였다. 굵은 골재 최대치수 25mm, 압축강도 40MPa, 슬럼프 180mm 기준으로 배합한 콘크리트 공시체 자료로부터 재령일별 압축강도 분포와 외기온도, 콘크리트 온도, 슬럼프, 공기량, 염분량 등의 인자가 콘크리트 압축강도에 미치는 영향을 조사하였다. 조사 결과 "콘크리트 타설시 콘크리트 온도와 외기온도의 차이"가 공시체 7일과 28일 압축강도에 미치는 영향이 가장 큰 것으로 확인되었다.

• 대한화학회지
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• 제19권3호
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• pp.186-192
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• 1975

燃炭을 燃燒시킬 때 흙통중에서 一定量의 煉炭을 一定時間 燃燒를 持續시키기 위하여 空氣의 供給을 制限하게 되므로 많은 量의 一酸化炭素가 發生한다. 그러므로 一酸化炭素의 發生을 抑制하는 基本實驗으로 窒素, 酸素 및 一酸化炭素의 混合가스 및 炭素의 存在下에서 一酸化炭素의 燃燒率을 測定한 結果 一酸化炭素 燃燒溫度는 $700^{\circ}C$以上이고 空氣의 供給이 增加 할수록 一酸化炭素의 燃燒率이 改善됨을 알았다. 이러한 事實에서 燃燒時間의 延長과 一酸化炭素의 發生 抑制는 서로 相反되므로 두 가지 條件을 滿足시키는, 보다 效果的 燃燒裝置를 考案하였다. 즉 內徑이 다른 二重鐵筒으로 暖爐를 만들어 若干의 二次空氣가 에어자켓 下部에서 들어가 上部의 작은 구멍에서 나오게끔 하면 燃燒中인 煉炭과 熱交換되어 燃燒雰圍氣의 溫度는 低下된다. 따라서 燃燒時間은 길어지면 또 二重鐵筒을 通하여 上昇하는 豫熱空氣는 一酸化炭素의 再演燒를 促進시키게 되므로 一酸化炭素의 發生量은 흙통을 使用하였을때 보다도 1/20 程度로 減少된다.

• 한국의류학회지
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• 제21권4호
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• pp.750-756
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• 1997

The purpose of the study was to investigate a transmittance rate of UVB (Ultraviolet B) through summer fabrics and a protection rate of summer fabric from UVB. The subjects were randomly selected 159 fabrics from Korean common summer fabrics. The protection rates of 159 fabrics from UVB were measured by UVB lamp and UVB sensor, and 14 fabrics among these fabrics were selected for an assay of MTT(3-(4, 5-dimethylthiazol-2-yl) -2, 5 -diphenyltetrazolium). The protection rate of fabrics from cell toxicity of UVB was measured by investigating the difference of the amount of cell toxic substance on between fabrics covered with and without HeLa cell The average protection rate of 159 fabrics from UVB was 95.08%. As result findings, three negative correlations were found between: 1) the transmittance rate of UVB and the amount of MTT on fabrics (y=0.0373+0.O0518 x, r=-0.9323, p<0.001); 2) the air permeability of fabrics and the amount of MTT (r: -0.79, p< 0.01); 3) the air permeability of fabrics and the protection rate of fabrics from UVB (r=0.89, p<0.01). However, there was no effect of thickness of fabrics on the protection rate from UVB and the amount of MTT.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2485-2491
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• 2009

2007년 4월 1일부터 5월 31일까지 2개월 동안 1개 광역도 1개 도농복합도시 지역의 노인요양시설 5곳을 대상으로 실내 외의 공기 중 바이오에어로졸 조사하기 위해 관성충돌 채취법을 적용한 미생물 채취기인 air $IDEAL^{TM}$(Biomerieux)를 이용하여 면양혈액한천배지와 Sabouraud Dextrose Ager를 사용하여 채취하여 배양하였다. 배양하여 분리 동정한 결과 다음과 같은 결과를 얻었다. 1. 각 시설별 전체 미생물의 분리는 300 L 실내에서 S 요양원이 263 cfu/$m^3$로 가장 많았고, U 요양원이 123 cfu/$m^3$로 가장 낮은 수가 분리되었다. 2. 실내에서 300 L를 채취한 배지에서 분리된 세균의 수는 기타 동정되지 않거나 비병원성 그람양성구균이 321개로 가장 많이 분리되었으며, 기타 그람양성구균의 대부분은 CNS(Coagulase Negative Staphylococcus)이었다. 3. 실내에서 300 L를 채취한 배지에서 분리된 진균의 수는 Aspergillus spp. 가 66개로 가장 많이 분리되었으며, 다음으로 Mucor spp. 62개, Penicillium spp. 53개, Alternaria spp. 50개, 기타 동정되지 않거나 비병원성 진균들이 42개의 순으로 분리되었다. 4. 실내 외의 오염비율은 실외보다는 실내에서 모두 평균 집락수가 많았으며, 300 L와 500 L의 공기량의 차이를 둔 조사에서는 공기량이 많을수록 양적으로는 많은 세균이 검출되었지만 균종으로는 큰 변화가 없었다.

• 동력기계공학회지
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• 제21권2호
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• pp.77-82
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• 2017

In the fishing boat, freshwater ice is loaded on the fishroom in advance and it is used for storage of fishes. However, it causes degradation of catches' freshness. Therefore, seawater ice machine on board is necessary for the fishing industry. In this study, seawater ice machine with drum type evaporator was manufactured, and the system was tested under various operating conditions having an influence on the COP and amount of ice produced. The main results are as follow : The COP of the system gets larger when the evaporation temperature and rotation speed of the drum in the evaporator increases. The most effective refrigerant is R22 and the value of the COP was 1.43 times higher than that of R404A. The amount of produced ice increases with respect to increment of the evaporation temperature, while that decreases with respect to increment of the evaporator drum rotation speed.

• 한국산업보건학회지
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• 제32권2호
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• pp.111-115
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• 2022

Objectives: The purpose of this study is to verify whether droplet-induced propagation, the main route of infectious diseases such as COVID-19, can occur in semiconductor FAB (Fabrication), based on research results on general droplet propagation. Methods: Through data surveys droplet propagation was modeled through simulation and experimental case analysis according to general (without mask) and mask-wearing conditions, and the risk of droplet propagation was inferred by reflecting semiconductor FAB operation conditions (air current, air conditioning system, humidity, filter conditions). Results: Based on the results investigated to predict the possibility of spreading infectious diseases in semiconductor FAB, the total amount of droplet propagation (concentration), propagation distance, and virus life in FAB were inferred by reflecting the management parameter of semiconductor FAB. Conclusions: The total amount(concentration) of droplet propagation in the semiconductor fab is most affected by the presence or absence of wearing a mask and the line air dilution rate has some influence. when worn it spreads within 0.35~1m, and since the humidity is constant the virus can survive in the air for up to 3 hours. as a result the semiconductor fab is judged to be and effective space to block virus propagation due to the special environmental condition of a clean room.

• 환경영향평가
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• 제14권3호
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• pp.117-126
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• 2005

This study was executed to know the best matrix of photochemical ozone reduction in the metropolitan area. For this object, we used the OZIPR(Ozone Isopleth Plotting Package for Research) model for comparing the effectiveness of VOCs and NOx amount variation about the ozone creation. Among the various ozone reduction scenarios, 50% reduction of VOCs from organic solvent and road traffic respectively was the best matrix for ozone reduction. Although it needs more accurate assessment and confirmation of VOCs and NOx emission amount data, according to existing data, the control of VOCs is the best way for photochemical ozone reduction in Seoul.

• 한국항공운항학회지
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• 제30권3호
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• pp.86-91
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• 2022

This study empirically analyzes the patterns of import and export of air cargo between Korea and EU member states. In order to understand the detailed characteristics of the air transport sector, the amount of trade was analyzed by dividing it into exports, imports, and trades. As a result of the analysis, in terms of exports, imports, and trade, both EU member states' GDP per capita and Korea's GDP showed positive directions, while EU member states' GDP and Korea's per capita GDP both showed negative directions. In addition, international oil prices and exchange rates, which were expected to have an effect on aviation trade, did not show significant results in this study. On the other hand, when applying the fixed-effect model, both the country area and the number of airports excluded from the analysis were analyzed as positive directions as a result of the Houseman Taylor analysis.