To ensure the safety and functionality of a railroad bridge, maintaining the integrity of the bridge via continuous structural health monitoring is important. However, most structural integrity monitoring methods proposed to date are based on modal responses which require the extracting process and have limited availability. In this paper, the applicability of the existing damage identification method based on free-vibration reponses to time-domain deflection shapes due to moving train load is investigated. Since the proposed method directly utilizes the time-domain responses of the structure due to the moving vehicles, the extracting process for modal responses can be avoided, and the applicability of structural health evaluation can be enhanced. The feasibility of the presented method is verified via a numerical example of a simple plate girder bridge.

본 연구는 선박에서 발생할 수 있는 화재연기의 위험성을 인식시키고 비상대응능력을 향상시키기 위해 선내에 안전교육을 위 한 환경을 구축하고 시나리오를 개발 운영하면서 획득한 실습생의 상황별 이동특성을 측정분석한 것으로, 그 결과를 정리하면 다음과 같다. 연기가 없는 조건에서는 익숙한 이동경로에 장애가 발생한 경우와 그렇지 않은 경우의 각 피난이동 상대속도 사이에 차이가 없지만, 실내에 연기가 충진되어 가시도가 매우 낮은 조건에서는 시야불량에 따른 이동능력 저하로 인해 그렇지 않은 경우에 비해 평균상당속도 가 62.5% 감속되었다. 시나리오에 관계없이 단순이동경로에 비해 복잡이동경로의 평균 상당속도가 빠르고 표준편차도 작게 나타났다. 연기가 충진된 경우에 대한 단순 데이터 평가에서는 전체이동경로와 복잡이동경로의 상대속도 확률분포가 매우 유사하였지만, 전체이동경 로의 상대속도에 대한 복잡이동경로의 상대속도비율의 개인간 변동폭은 매우 컸다. 한편, 상당속도는 가시거리의 로그함수로 표현할 수 있었다. 또한 실습생의 긴장감이 증가하면서 모든 경로에서 상대속도가 빨라졌다.

In this study, the heat transfer characteristics of pilot wave heat exchanger for white smoke reduction system was investigated. The performance of the wave and honeycomb heat exchanger combined with the first stage, second stage and third stage was tested using a calorimeter. Air and water inlet/outlet temperature and flow rate, pressure drop and dehumidification amount were measured to compare the heat transfer performance according to the type and the combination of heat exchanger. The heat transfer rate and dehumidification amount of the wave heat exchanger were higher than that of the honeycomb heat exchanger, and the pressure drop was low. As the stage increased, the heat transfer rate and the increase of the dehumidification amount were more pronounced, and the pressure drop linearly increased. The wave heat exchanger had a lower flow resistance than the honeycomb heat exchanger with the honeycomb structure and had a higher heat transfer effect due to the convection, so the water outlet temperature was higher in the wave heat exchanger.

선박의 기계식 환기시스템은 화재발생 시 연기의 생성과 확산 특성에 영향을 미치고, 이는 피난자의 피난경로 상의 가시도를 방해함으로써 피난자의 연기로 인한 피해를 증가시킬 위험성이 크다. 이에 이 연구에서는 선박 거주구역에서 화재발생 시 기계식 급·배기시스템이 연기확산에 미치는 영향과 위험성에 대하여 FDS를 활용하여 평가하고 화재 시 급·배기시스템을 효율적으로 사용할 수 있는 방안을 제안하였다. 연구결과 화재가 발생한 장소에 급·배기시스템이 함께 작동되고 있는 경우에는 현재 권장되고 있는 급·배기시스템을 멈추는 방법보다 작동을 유지하는 것이 효과적이고, 배기시스템만 작동되는 곳에서 화재가 발생한 경우에는 화재가 발생한 구역 이외의 구역에서 급기시스템을 함께 작동시키는 것이 피난시간을 확보하는데 효과적인 것으로 예측되었다. 그러나 화재가 발생한 곳에 급기시스템만 있는 경우에는 급기시스템이 연기확산을 가속시키기 때문에 급기방식을 중단시켜 연기의 확산을 최대한 억제할 필요가 있음을 확인하였다.

In this paper which was performed to bring public attention to the need for developing an photoelectric smoke detector that detects smokes emitted from diverse fire sources, it was confirmed that the photoelectric smoke detector may not respond to certain smoke types depending on the size and color of smoke particles. The test was performed on a photoelectric smoke detector which is being used generally for specific fire targets specified in UL268, including paper fire, wood fire and flammable liquid fire, while the actual response performance of the fire detector, as well as respective smoke particles collected from different fire source which were photographed with a SEM(Scanning electron microscope) were analyzed in the test for this study.

This study investigated the smoke blocking and control systems for the safety of residents evacuation and for the prevention of smoke spread through the central corridor in the event of central corridor type of intelligent building fire. We offered additional ways of utilizing smoke ventilators and intake ventilation equipment and utilized CFD-based fire simulation program(FDS Ver.5.5.3) in order to analyze the effect. As a result, many differences in the smoke block effect, depending on the application of smoke ventilator and location of installation, was found. In addition, the result was found that larger effect was showed not in the case of application of smoke ventilator in central corridor only but application in fire room. The reason is that the smoke leakage is blocked primarily as air is flowed in the fire room through open door by operation of intake smoke ventilator in the public corridor and secondarily, the smoke leakage to the public corridor could be blocked as fire and smoke were released to the opened smoke ventilator continuously. Especially, the effect was maximized through complex interactions by applying smoke ventilator and intake ventilation equipment in corridor together rather than applying smoke ventilator and intake ventilation equipment independently. The proposed measure through this study shall be considered from architectural plan as one of ways for blocking from smoke spread to the central corridor in the central corridor type of intelligent building. In addition, flaws on regulation shall be established and supplemented.

This study was conducted to determine the impact of smoke-free regulations on the environment in personal computer(PC) rooms by measuring indoor levels of particulate matter smaller than 2.5 μm(PM2.5) before and after the implementation of the regulations. PM2.5 concentrations of 34 PC rooms in Seoul were measured before and after the regulations took effect. A real-time monitor was used to measure PM2.5 concentrations. A field technician recorded the characteristics of PC rooms including indoor volume, number of floors, and the presence of a smoking room and counted the number of burning cigarettes, cigarette butts, vents, and patrons. While outdoor PM2.5 concentrations and the number of patrons were not changed, indoor PM2.5 concentrations, the number of burning cigarettes and cigarette butts in PC rooms were significantly decreased after the regulations were implemented (p < 0.001). Geometric mean(GM) of indoor PM2.5 concentrations in the PC rooms was 139.6 μg/m3 before the regulations took effect and 55.7 μg/m3 after the regulations implemented. After the regulations, smokers were observed in 11 of the 34 PC rooms in which PM2.5 concentrations were not significantly decreased(p = 0.18). When smokers were not observed after the regulations, the GM of indoor PM2.5 concentrations was 37.2 μg/m3. Although PM2.5 concentrations in some PC rooms were decreased after the regulation, higher PM2.5 concentrations were observed in PC rooms with smokers. As such, compliance with the smoke-free regulations should be strictly ensured to achieve a better indoor air quality.

담배훈연을 이용한 진딧물의 살충효과를 검정하기 위해 건조 담뱃잎을 이용하여 실험실과 온실에서 훈연시험을 실시하였다. 아크릴케이지 에서 담배를 훈연하였을 때 담배품종은 버어리종이 황색종보다 싸리수염진딧물에 대한 살충력이 높게 나타났다. 세 종의 진딧물 복숭아혹진딧 물, 목화진딧물, 싸리수염진딧물을 각각 기주를 이용하여 아크릴케이지에서 50 mg의 담뱃잎으로 훈연시험을 실시한 결과 살충율은 싸리수염진 딧물(97.2%)>목화진딧물(94.4%)>복숭아혹진딧물(63.9%) 순으로 나타났다. 복숭아혹진딧물은 기주를 가지로 했을 때 훈연에 의한 살충율이 배추를 기주로 했을 때보다 높게 나타났다. 100 m 2 규모의 온실에 황색종의 담뱃잎을 2시간 훈연 시 200 g을 이용하였을 때 싸리수염진딧물에 대 해 95.4%의 방제가를 보여주었으나 100 g을 이용하였을 때는 28.9%의 방제가를 보여주었다. 100 g의 담뱃잎은 14시간 훈연하였을 때는 2시간 훈연보다 살충효과가 2배 이상 높아졌다. 오이재배 농가 온실에서 담배훈연을 하였을 때 처리 후 목화진딧물의 방제효과는 80% 이상이었다. 온 실 환경에 따라 적절한 양과 시간을 선택해 사용한다면 담배훈연은 온실 내 발생하는 진딧물에 대한 효과적인 방제방법으로 사용할 수 있을 것이다.

본 연구에서는 한반도 황사 사례 동안 WRF 기상모델과 SMOKE 배출량모델, CMAQ 및 CMAQ-MADRID 대기질 모델을 이용하여 다양한 황사 발생량 경험식에 대한 PM10의 농도를 추정하였다. 특별히 Wang et al.(2000), US EPA 모델, Park and In(2003), GOCART 모델, DEAD 모델의 5가지 황사 발생 경험식이 중국과 몽골 등의 황사 발생량을 추정하기 위해 WRF-SMOKE-CMAQ(MADRID) 모델에 적용되었다. 일기도, 후방궤적 및 위성이미지 분석에 따르면 한반도로의 황사 수송은 절리저기압(위성에서 콤마형 구름)과 관련된 지상 전선의 뒤쪽에서, 그리고 상층 제트류의 발달에 기인한 파의 정체현상과 함께 상층 골에서의 풍속이 하층으로 전이되는 풍하 바람에 의해 생성되었다. 그리고 WRF-SMOKE-CMAQ 모델링 결과, 황사의 시 공간적 분포에 있어서는 Wang et al.(2000)의 경험식이, 평균 편의 및 평균 제곱근 오차에서의 정확도 부분에서는 GOCART 모델의 경험식이 관측값을 보다 잘 모사하는 것으로 나타났다. 또한 Wang et al.의 경험식을 이용한 황사의 연직분포 분석 결과에서 강한 황사 사례(2007년 3월 31에서 4월 1일 800 μg/m3 이상)의 경우는 황사 수송이 한반도 상공 대기 경계층 내를 통과하였기 때문으로, 약한 황사 사례(2009년 3월 16일과 17에 400 μg/m3 이하)의 경우는 황사 수송이 경계층 위를 통과하였기 때문으로 나타났다. 또한 CMAQ 모델과 CAMQ-MADRID 모델에서의 미세먼지(PM10) 민감도 분석 결과에서는 CMAQ-MADRID 모델이 CMAQ 모델에 비해 한반도를 포함한 동아시아 지역에서 최대 25 μg/m3 정도가 높게 모사되었고, 모델 내 구름 액상과정에 의해서는 최대 15 μg/m3 정도가 제거되는 것으로 나타났다.

본 논문에서는 연기 애니메이션을 위한 GPU 기반의 펜앤잉크 렌더링 방법을 제안하였다. 제안된 방법은 광선 투사 방법을 이용하여 화면에 그려질 연기의 표면점을 추출하였다. 계산된 표면점에 대해 밝기값과 곡률을 계산하여 스트록의 방향과 스트록의 밀도를 정하였다. 각 스트록은 기하 쉐이더를 이용하여 사각형을 생성하여 스트록 텍스쳐를 매핑함으로써 렌더링하였다. 이때, 사각형의 모양을 곡률을 따라 변형함으로써 스트록이 곡률 방향을 따라 그려지도록 하였으며 텍스쳐에 그려질 스트록의 개수를 밝기값에 따라 정함으로써 스트록의 밀도를 조절하였다. 실험 결과 평균 초당 25 프레임의 속도로 연기 애니메이션에 대한 펜앤잉크 렌더링을 생성할 수 있었다.

In this paper, the effect of oxygen component in fuel on the exhaust emissions has been investigated for a direct injection diesel engine. It was tested to estimate change of engine performance and exhaust emission characteristics for the commercial diesel fuel and oxygenated blended fuel which has seven kinds of mixed ratio. And, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission have been investigated. Ethylene glycol mono-n-butyl ether(EGBE) contains oxygen component 27% in itself, and it is a kind of effective oxygenated fuel of mono-ether group that the smoke emission of EGBE is reduced remarkably compared with commercial diesel fuel, that is, it can supply oxygen component sufficiently at higher loads and speeds in a diesel engine. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel and cooled EGR method.

Diesel particulate matter is one of the major harmful emissions under strict regulations. The exhaust after-treatment devices are added to the diesel engines as stricter regulations are introduced worldwide. In the present study, new system of smoke reduction of diesel engine is proposed. This new system is using suction equipment and fiber glass filter included moisture for capture smoke. For verification of new system experiments are performed at diesel engine. As a result it is founded that smoke is decreased.

The Effects of cooled and hot EGR(exhaust gas recirculation) on the characteristics of smoke and NOx emission have been investigated using a single cylinder, water-cooled, four cycle, DI diesel engine at several loads and speeds. In this study, a manually controlled EGR system was installed on a agricultural diesel engine which was operated at various operating system. And, the effects of hot EGR and cooled EGR on smoke and NOx emission were compared. The results showed that cooled EGR method was more effective than hot EGR method on smoke and NOx emission.

Over the past years, many research works have been carried out to investigate the factors which govern the performance of diesel engine. The air pollutant emission from the diesel engine is still a significant environmental concern in many countries. In the present study, new system of smoke reduction of diesel engine is proposed. This new system is using vacuum equipment and STS filter for capture smoke. To confirm new system experiments were performed at engine dynamometer. As a result of this experiment, the smoke reduction ratio of this system was identified high reduction ratio than PDPF. But the power of this system application was measured 10% decrease than base engine performance. There were improvement effects of using STS filter than ceramic filter.

Secondhand smoke (SHS) is one of major public health threats in morbidity and mortality. Several national and regional comprehensive smoke-free regulations have been implemented to prevent public health exposure, but not in Korea. The purpose of this manuscript was to review impacts of the national or regional smoke-free legislations on indoor air quality, health effects and smoking behaviors. Indoor air quality has been improved significantly after smoke free policy. Such improvement was measured by fine particulates and urinary cotinine. Respiratory and cardiovascular health effects were significantly improved after smoke free policy. This is an indirect evidence of association between secondhand smoke exposure and the health effects. Respiratory symptoms were improved as short as one month after smoke free policy. Smoke free policy was also associated with improved perception of danger of secondhand smoke. Reduction of smoking prevalence was also unexpected benefit of smoke free policy. As reviewed in this paper, smoke free policy can be beneficial to indoor air quality, health effects and smoking behaviors. Since Korea does not have comprehensive smoke free policy yet, it is strongly recommended to implement national comprehensive smoke free policy.

Burning mosquito coils in indoor environments maygenerate smoke that can control mosquito effectively. This practice has been used in numerous households in Korea. However the smoke may contain air pollutants of health concern. We conducted the present study to characterize the emission from two common brands of mosquito coils from Vietnam and Malaysia, respectively. We measured mass emission of air pollutants of nitrogen oxides (NOx), fine particulate(PM2.5), formaldehyde (HCHO), total volatile organic compounds (TVOCs), carbon monoxide (CO) and carbon dioxide (CO2) in completely closed chamber. Air pollutants concentrations resulting from burning mosquito coils could substantially exceed health-based air quality standards orguidelines. Under the same condition, air pollutants were measured by cigarette smoking to compare mosquito coil. Burning one mosquito coil would release the same amount of PM2.5 mass as burning 20~58 cigarettes. The emission of HCHO from burning one coil can be as high as that released from burning 27 cigarettes.