Urban green spaces can mitigate negative impacts of urban heat island effect by creating cooling buffer zones. These cooling areas improve micro-climatic conditions and human health. Green space is important to reducing urban air temperature maxima and variation. Thus, there is an expectation that small green spaces (SGs) provide high cooling effects and thus make air temperatures drop. Meanwhile, such an effect in urban areas has been under-explored and needs more detailed spatial and temporal data. The purpose of the study was to develop a measurement method to detect temperature of various SGs with TVC and find the effect of TVC on accuracy of measured air temperature data in comparison with other non ventilation devices. We updated the cad file of the study site through comparing it with Google Map and conducting field surveys on the site. Transect survey was required to build a measurement route. We toured the study site by walk repeatedly to get the optimistic route which would have enough data points. One of considered routes which were inside of the forest and could make us get significantly influencing data was not founded for no trails so excluded in our study. After the field survey, we observed the study routes through a digital camcorder (Gopro) and recorded them on the cad file of the site because these data points should include air temperature and time data in their attribute table. As for transect survey, a researcher walked through the defined routes and collected air temperature data with two TVCs every second and two Testo loggers covered by aluminum foil every minute at the height of 1.5m from the ground. Stationary survey was conducted with two TVCs in every second data collection and two Testo loggers covered by aluminum foil in every minute data collection on the resting area at the entrance of the site. One of TVCs and one of Testo loggers were set at the height of 0.5m while the others of TVCs and Testo loggers were at the height of 1.5m. On the stationary point, other microclimate variables such as wind velocity, wind direction and solar irradiance were also measured and recorded every minute. We repeated the measurement for one day or two days a month (November, 2016 ~ May, 2017) and four times a day. The measuring days were selected when they were clean and calm. As a result, air temperature from TVCs was entirely lower than that from Testo loggers on the stationary survey. This trend was shown during the day rather than after sunset. The difference of air temperature from between TVCs and Testo loggers ranged from 2 ℃ after sunset to 5 ℃ at 16h. At the height of 0.5m, a Testo logger's data showed much higher than a TVC's data. These results show that Testo loggers tend to be easily influenced by the change of solar radiation. Moreover, there was the ventilation effect at the stationary. So no ventilation could be the main reason why Testo loggers' data were high. However, TVCs' lower temperature explains how effectively these devices block the solar radiation and ventilate air inside the cylinder.
We experienced an 18-month-old patient with congenital lobar emphysema who underwent one-lung ventilation. With con-sideration that positive pressure ventilation could induce cardiopulmonary distress, induction was performed with spontane-ous breathing using sevoflurane without neuromuscular blocking agent. Bronchospasm occurred after intubation and posi-tion change, twice. He was relieved by administration of neuromuscular blocking agents. We discussed induction methods with minimal positive-pressure ventilation and the treatments for bronchospasm.
비닐하우스 내 강제환기가 시금치 노균병 발생에 미치는 영향을 구명하기 위해 비닐하우스에 수직환기팬 및 수평공기순환팬을 각각 설치한 후 밤 동안 환기를 시킨 하우스와 환기팬을 설치하지 않은 하우스에서 시금치를 재배하면서 온도 및 습도의 변화, 시금치 생장 정도 및 노균병 발생 정도를 조사하였다.
하우스 내의 온도변화는 각 하우스 별로 큰 차이가 없었으나, 밤 동안 상대습도는 수직강제환기팬을 설치한 하우스가 팬을 설치하지 않은 하우스보다 9.2% 낮게 유지되었다. 파종 60일 후에 조사한 시금치의 개체 당 생체중은 수직강제환기팬을 설치한 하우스에서는 17.8g으로 환기팬을 설치하지 않은 하우스의 10.1g과 비교하여 7.7g 높았다. 노균병은 환기팬을 설치하지 않은 하우스에서는 파종 후 20일부터 발생하기 시작하여 60일 후에는 34.7%의 이병엽률을 보였으나, 수직강제환기처리한 하우스에서는 파종 40일 후부터 발생하기 시작하였으며 60일 후 이병엽률은 4.0%로 매우 낮았다.
야간에 비닐하우스 내 공기를 수직강제환기팬을 이용하여 환기시킨 결과 환기팬을 설치하지 않은 하우스와 비교하여 시금치 수확량은 76.2% 증가되었으며, 노균병 발생은 20일 정도 늦었으며, 88.5% 노균병 발생 억제효과가 있었다.
A ventilation model was developed for predicting the air change per hour(ACH) in buildings and the airflow rates between
zones of a multi-room building. In this model, the important parameters used in the calculation of airflow are wind velocity,
wind direction, terrain effect, shielding effect by surrounding buildings, the effect of the window type and insect screening,
etc. Also, the resulting set of mass balance equations required for the process of calculation of airflow rates are solved using a
Conte-De Boor method.
When this model was applied to the building which had been tested by Chandra et al.(1983), the comparison of predicted results by this study with measured results by Chandra et al. indicated that their variations were within -10%~+12%. Also, this model was applied to a building with five zones. As a result, when the wind velocity and direction did not change, terrain characteristics influenced the largest and window types influenced the least on building ventilation among terrain characteristics, local shieldings, and window types. Except for easterly and westerly winds, the ACH increased depending on wind velocity. The wind direction had influence on the airflow rates and directions through openings in building.
Thus, this model can be available for predicting the airflow rates within buildings, and the results of this study can be useful for the quantification of airflow that is essential to the research of indoor air quality(temperature, humidity, or contaminant concentration) as well as to the design of building with high energy efficiency.
Respiratory distress resulting from a neuromuscular disorder is often misdiagnosed and not managed properly until development of severe respiratory failure. Amyotrophic lateral sclerosis (ALS) is a rare but archetypical motor neuron disease. Most cases manifest as weakness, muscular atrophy, and progressive paralysis of the limbs. Late stage of the disease is characterized by respiratory failure due to respiratory muscle weakness. In a few cases, 3% of patients, respiratory failure is the initial presentation, preceding other symptoms. We report on a case of ALS accompanied by acute respiratory failure and weaning failure, with a review of the literature.
본 연구에서는 양파 채종재배 할 경우 차광망설치와 온실천창 개폐, 환기 조건이 양파 채종량에 미치는 영향을 알아보기 위한 연구이었다. 본 연구 결과는 다음과 같다. ‘6701’과 ‘6704’는 채종 방법에 따른 온실 온도의 차이에 대한 채종량은 10시경에 부의 상관관계를 보이나 시간이 지날수록 상관이 거의 없는 것으로 분석되었다. ‘6701’은 채종방법에 따른 온실 습도의 차이에 대한 채종량은 14시까지의 습도에 따라 고위정상관을 이루며 대부부분 상관이 없는 것으로 조사 되었다. ‘6701’과 ‘6704’는 채종방법에 따른 온실 광도의 차이에 대한 채종량은 대부분 부의 상관이 있는 것으로 나타났다. 따라서 양파를 채종 할 경우에는 습도 관리가 영향이 크게 미치는 것으로 생각되었다.
Industrial natural ventilation systems consist of gravity ventilator, the high/low windows and doors. Especially, the high windows play an important role in the industrial natural ventilation systems. Generally speaking, industrial high windows are divided into 3 types; louver type, 45° open type and 90° open type. This study was numerically and experimentally conducted. Three types of windows were tested to know the ventilation characteristics and estimate the ventilation efficiencies. Numerically, computational fluid dynamics software (AIR PAK Ver. 2.0) was used to observe the flow characteristics inside the industrial building and the concentration contours generated by the tracer gas method. Experimentally, the flow visualization technique and the tracer gas method were applied with the model building to characterize the flow pattern inside the model building and to estimate the ventilation efficiencies with the different windows. It was found that 90° open type window was most effective for the discharge of pollutants from the industrial building. On the other hand, the louver type window was found to be less effective than any other windows.
Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. The purpose of this study was to develop an alternative method to characterize indoor environmental factors by multiple indoor and outdoor measurements. Using a mass balance model and regression analysis, penetration factor (ventilation rate divided by the sum of ventilation rate and deposition constant) and source strength factor (source strength divided by the sum of ventilation rate and deposition constant) were calculated using multiple indoor and outdoor measurements. Subsequently, the ventilation rate and NO2 generation rate were estimated. Mean of ventilation rate was 1.41 ACH in houses, assuming a residential NO2 deposition constant of 0.94 hr-1. Mean generation rate of NO2 was 16.5 ppbv/hr. According to house characterization, inside smoking and family number were higher NO2 generation rates, and apartment was higher than single-family house. In conclusion, indoor environmental factors were effectively characterized by this method using multiple indoor and outdoor measurements.
A numerical study with Envi-met model is experimented to investigate the characteristics of wind pattern in apartment complex. In all case, most conditions such as wind speed, temperature, and surface features are considered as the same, but wind direction is the only different factor. The wind directions considered in this study have a meaning of prevailing wind direction. When the prevailing wind with the direction of 170° blows into the complex, the ventilation passage toward the outside of complex is formed and the stagnation of air is not expressed. In case of having the direction of 300°, most evident ventilation passages are composed. When the inflow wind direction is the northeast, 30°, there is some possibility of stagnation phenomenon. This is because the arrangement of buildings makes a right angle with the inflow wind direction.
지하 동굴식 처분장의 건설, 운영 및 중-저준위 방사성폐기물을 처분한 이후 발생하게 되는 오염물질(Rn, CH CO, HS, Radiolysis에 의한 방사능 가스 등)은 적절한 공기량을 필요로 한 곳에 정확히 분배시킬 수 있는 환기시스템에 의해 통제되도록 하여야한다. 특히 지하 처분장은 여러 개의 진입 터널, 저장 터널, 공기 유입-배기 터널, 수직갱 등으로 이루어진 복잡한 회로망의 형태로 나타나기 때문에 이에 적절한 기술적 접근이 필요하다. 본 논문에서는 이러한 환기시스템 구축을 위한 기술적 접근을 위해 미국의 WIPP (Waste Isolation Pilot Plant)처분장과 스웨덴의 SFR (Slutforvar for Reaktoravfall) 중-저준위 처분장을 모델로 하여 두 처분장의 소요환기량을 선정하고 설계상 통풍로의 단면적, 길이, 표면 거칠기 등을 고려한 환기회로를 구성하였으며, 수학적으로 계산되는 각 회로의 저항에 대해 기술하였다. 또한 이를 바탕으로 적절한 선풍기의 용량과 수직갱 운용방안을 설계하였다. 두 처분장의 지형상의 규모 및 환기시설 비교 결과, SFR 처분장에 비해 WIPP 처분장에서와 같이 병렬구조가 많을수록 처분장 전체의 저항이 감소되며 이러한 결과로 환기시스템의 운용비 절감효과를 얻을 수 있다는 결론을 얻었다. 따라서 처분용량 증대를 위한 대단면의 SFR 처분장 구조와 전체 저항 감소를 위한 WIPP 처분장의 병렬구조를 조합한 형태가 가장 합리적이며 효율적인 환기가 이루어질 수 있을 것으로 사료된다.
자연환기는 처분장의 작업 환경 및 위생, 부유 방사성 핵종의 노출 등과 같은 안전문제에 있어 자연환기 자체만으로는 기계적 강제 환기에 비해서 덜 효과적이지만 처분장 내의 수분제거, 작업 환경 조성과 관련하여 라돈 (Rn) 가스의 희석과 같은 향후 처분장의 장기적 환경을 위해서는 중요한 역할을 할 수 있고, 환풍기와 같은 환기 설비를 이용해야하는 기계환기에 비해 경제적으로 매우 효과적 일수 있다. 본 논문에서는 지하 처분장의 건설 및 운영 기간동안 자연환경 조건에 따라 처분장에 스스로 생기는 자연 환기의 타당성에 대하여 기술하였다. 자연 동굴을 통한 자연환기 유사에 의해 밝혀진 증거들과, 수직갱을 갖는 산악 도로터널에서의 자연 환기 측정, 그리고 주어진 자연환기 압력에 의한 공기 발생량 계산 등을 통해서 자연 환기는 한국형 지하 방사성 폐기물 처분장에 잠재적으로 매우 유익함을 알 수 있다. 효과적으로 유도된 자연 환기는 방사성 폐기물 처분장 내에 발생하는 열과 습도, 그리고 라돈 가스를 제어하기에 경제적으로 좋은 방법이 될 수 있다. 자연환기를 통해 처분장의 전반적 열적 특성은 개선될 수 있고, 수분으로 포화된 공기는 효과적으로 건조되고 그 건조상태 유지 기간은 확장 될 수 있을 것이다.
방사성 폐기물의 지층 처분장 건설 및 운영을 위한 개념 선정 단계에서는 폐기물 운반 및 거치뿐 아니라, 처분장의 건설/운영/폐쇄 기간 동안 지하 처분장의 작업 환경 및 위생, 안전, 그리고 처분장내의 수분 제거와 같은 향후 처분장의 환경을 위해 처분장 환기시스템에 대한 고려가 향후 처분장의 환경을 위해 반드시 필요하다. 본 논문은 동굴처분 방식의 중-저준위 처분장 및 지하 심부에 위치하게 될 고준위 처분장에 대한 환기시스템 개념설계 기준 및 요구사항에 대한 내용이다. 방사성폐기물 처분장의 환기 시스템에서 가장 주된 기본 설계 개념은 처분장 건설과 폐기물저장을 위한 작업활동을 위해 각각 독립적이고 분리된 환기시스템을 적용하여야 한다는 것이다. 본 논문에서는 방사성폐기물 처분장의 환기시스템의 설계과정에 대해 기술하고 환기회로 모델링 방법, 자연 환기, 환기 모니터링 시스템과 실시간 환기 시뮬레이션, 화재 시뮬레이션 및 비상 방재 시스템에 관한 사항도 논의하였다
Indoor air quality is affected by source strength of pollutants, ventilation rate, decay rate, outdoor level, and so on. Although technologies measuring these factors exist directly, direct measurements of all factors are not always practical in most field studies. The purpose of this study was to develop an alternative method to estimate these factors by application of multiple measurements. For the total duration of 30 days, daily indoor and outdoor NO2 concentrations were measured in 30 houses in Brisbane, Australia, and for 21 days in 40 houses in Seoul, Korea, respectively. Using a box model by mass balance and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor (emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the ventilation and source strength were estimated. In Brisbane, the penetration factors were 0.59±0.14 and they were unaffected by the presence of a gas range. During sampling period, geometric mean of natural ventilation was estimated to be 1.10±1.51 ACH, assuming a residential NO2 decay rate of 0.8 hr-1 in Brisbane. In Seoul, natural ventilation was 1.15±1.73 ACH with residential NO2 decay rate of 0.94 hr-1. Source strength of NO2 in the houses with gas range (12.7±9.8 ppb/hr) were significantly higher than those in houses with an electric range (2.8±2.6 ppb/hr) in Brisbane. In Seoul, source strength in the houses with gas range were 16.8±8.2 ppb/hr. Conclusively, indoor air quality using box model by mass balance was effectively characterized.