• 한국산업융합학회 논문집
• /
• 제20권1호
• /
• pp.8-18
• /
• 2017

This research analyzed the ventilation effect of the multi-span greenhouse based on the types of greenhouse structure, weather conditions, and locations inside the greenhouse. To compare and analyze the ventilation effects with different types of greenhouse, the uniform environmental conditions should be selected in advance. But these factors are not controlled and require tense many precision facilities and labor forces. Thus, the CFD simulation was used for the air stream to be analyzed qualitatively and quantitatively. In addition, for the ventilation effect analysis, the TGD (Tracer Gas Decay) was used to overcome the shortcomings of the current ventilation measurement method. The calculation error of ventilation rate using TGD was low (10.5%). Thus, the TGD is very effective in calculating the ventilation efficiency. The wind direction of 90 degrees showed the best ventilation effect. The ventilation rate also decreased along the air circulation path, and the rate was the lowest around the outlet. The computed fluid method (CFD) turned out to be a power tool for simulating flow behavior in greenhouse.

• 한국연초학회지
• /
• 제24권2호
• /
• pp.107-112
• /
• 2002

There are many combination with the porosity of tipping paper and plug wrap for a design of ventilation rate of cigarette. This study was carried out to determine the effect of a design of permeability of tipping paper and inner or outer of plug wrap on the ventilation rate of cigarette with constant pressure drop in column part and filter part. Our results indicated that the higher the plugwrap porosity, the higher the ventilation rate and the less variable of cigarette in case of mono filter. But, in case of duel filter, the ventilation rate of cigarette was depended on the manufacturing method of filter plug, even though using the same porous plug wrap on inner and outer of filter. We also found that the porosity of outer plug wrap was more effect on the ventilation rate than the porosity of inner plug wrap. As the high porosity of inner plug wrap compared with the porosity of outer plug wrap, the less variable of ventilation rate of cigarette in any combination of the porosity of plug wrap. When we used the higher porous outer plug wrap than inner plug wrap, the ventilation rate of cigarette was high. Also, the higher the inner plug wrap porosity, the less variable of ventilation rate of cigarette.

• Tuberculosis and Respiratory Diseases
• /
• 제75권1호
• /
• pp.1-8
• /
• 2013

Several papers on respiratory and critical care published from March 2012 to February 2013 were reviewed. From these, this study selected and summarized ten articles, in which the findings were notable, new, and interesting: effects of high-frequency oscillation ventilation on acute respiratory distress syndrome (ARDS); safety and efficacy of hydroxyethyl starch as a resuscitation fluid; long-term psychological impairments after ARDS; safety and efficacy of dexmedetomidine for sedation; B-type natriuretic peptide-guided fluid management during weaning from mechanical ventilation; adding of daily sedation interruptions to protocolized sedations for mechanical ventilation; unassisted tracheostomy collar of weaning from prolonged mechanical ventilations; and effects of nighttime intensivist staffing on the hospital mortality rates.

• 한국자동차공학회논문집
• /
• 제9권3호
• /
• pp.201-209
• /
• 2001

Some passenger cars with sunroofs open at tilted positions experience reverse flows into cabin rooms and wind noises much louder compared to other cars. In this study, flows around open sunroofs are numerically studied with the variations of body leakage. The effects of body leakage on ventilation and wind noise of a sun roof are examined, in particular. Furthermore, flow visualization, pressure, and noise measured from wind tunnel and road tests are presented. The results show that too small body leakage results in poor performance of ventilation and generates high wind noise around a sunroof. It is therefore very important to secure an adequate body leakage from the early design stage to achieve better performance of a sunroof as well as passengers' comfort related to HVAC(Heating, Ventilation, and Airconditioning).

• 한국연초학회지
• /
• 제10권1호
• /
• pp.83-91
• /
• 1988

The effects of tipping paper permeability and plugwrap porosity on the ventilation and the pressure drop of cigarettes have been studied and the results obtained were as follows. 1. The single and the multiple regression equation to estimate tip ventilation were establised. In the equations, the observed values of the tip ventilation with the varieties the plugwrap porosity were content with them by the single regression equation. 2. As based on the statistical consideration of the above equation, the deviation of the observed tip ventilation versus the tipping paper permeability were higher than them to the plugwrap porosity. 3. The regression equations to calculate pressure drop ratio and the total ventilation rate in filter tip from the tea ventilation were obtained. According to the equation, the observed values of the pressure drop ratio were significantly similar to them calculated. 4. It was found that the equations could be applied to the calculation of the ventilation of cigarettes using the mechanical and micro laser perforation tipping paper as well as the electrically perforated tipping paper of this Study.

• 한국연초학회지
• /
• 제22권2호
• /
• pp.151-156
• /
• 2000

The variability of a ventilated filter cigarette depends on the details of its construction and on the variabilities of its components. Variations in filter ventilation arise from many sources, including variations in tobacco rod pressure drop, filter tip pressure drop, tipping paper permeability, and plugwrap permeability. To reduce the filter ventilation variability, the variability of filter ventilation levels in ventilated cigarettes is studied by Monte Carlo Analysis. For each trials a value is selected for tobacco rod pressure drop, filter tip pressure drop, tipping paper permeability, and plugwrap permeability. These values are selected randomly from a normal distribution based on the target and coefficient of variation for each input variable. The results of this analysis for filter ventilation variation suggest that the variations of filter ventilation are dependent on the details of cigarette designs studied and reducing the variability of any cigarette component will reduce filter ventilation variability. For typical cigarettes, variation in the permeability of tipping paper is usually the most significant contributor to filter ventilation variability. Results of a Monte Carlo Analysis could provide both general insights and specific practical guidance about the design of ventilated filter cigarettes.

• 한국연초학회지
• /
• 제30권2호
• /
• pp.103-108
• /
• 2008

The application of RECON(Reconstituted tobacco sheet) and the ventilation technology has been considered as very useful methods for controlling the tar and nicotine deliveries in modern blended tobacco. In this study, the effects of RECON contents in simulated blends on the smoke delivery and burning temperature were evaluated in three different ventilation levels. The ventilation showed a great influence on the burning temperature and smoke deliveries. The nicotine, tar and CO deliveries was greatly reduced by the ventilation. The amount of RECON showed the minor impacts on the smoke delivery. In high ventilation level such as 85 % ventilation, there was no distinct change in smoke deliveries by the amount of RECON.

• 터널과지하공간
• /
• 제22권5호
• /
• pp.365-372
• /
• 2012

본 논문에서는 환기구의 존재, 환기구 설치 대수, 환기구 용량, 복수 화원의 존재가 도로터널에서 발생한 차량 화재에 의한 연기 온도 분포에 미치는 영향을 평가하였다. 6개의 시나리오를 가정하였으며 FDS를 이용하여 시나리오 해석을 실시하였다. 해석 결과 환기구의 설치 대수가 증가함에 따라 연기의 온도는 감소하는 것으로 나타났지만, 환기구의 설치 대수가 2대인 경우와 3대인 경우에 온도 감소 효과는 거의 같은 것으로 나타났다. 환기구의 설치 용량은 환기구의 설치 대수 보다 연기 온도 감소에 더 큰 영향을 주는 것으로 해석되었다. 환기구가 없는 시나리오 No. 1과 복수 화원을 갖는 시나리오 No. 6를 제외한 나머지 시나리오에 대해서 해석한 결과 화원 상부에서의 연기 온도는 모두 $400^{\circ}C$ 이하로 나타났는데, 이는 화원 상부 연기층에서 발생하는 복사에 의해 화원 주변 가연물의 착화가 어렵다는 것을 나타낸다.

• 한국의류산업학회지
• /
• 제7권1호
• /
• pp.75-80
• /
• 2005

The purpose of this study was to investigate the effects of silt ventilation system on physiological responses. We measured rectal temperature, local skin temperature, clothing microclimate, blood pressure, heart rate, energy metabolism, body weight loss and subjective sensation during 70 minute, 50 min exercise period and 20 min rest period. The five women subjects randomly wore sportswear without slit ventilation system(NS sportswear) and sportswear with slit ventilation system(S sportswear) under the environmental condition of $25^{\circ}C$, 50%RH. The results of this study are as follows; Rectal temperature, mean skin temperature, clothing microclimate, blood pressure, heart rate, energy metabolism and body weight loss were significantly lower level in 'S sportswear'. In 'S sportswear', subjects replied less hot, less uncomfortable and less wet. Slit ventilation system can be used for bellow effect which is meaningful device of convection during exercise. We could find out that 'S sportswear' has advantage in physiological function.

• 한국터널지하공간학회 논문집
• /
• 제7권1호
• /
• pp.13-25
• /
• 2005

양방향 터널 (대면통행 터널)에 있어 방향별로 동일한 차속을 기준으로 터널환기를 분석하는 방법은 터널내 교통환기력을 거의 동일시하는 문제점을 내포하므로, 실제 양방향 터널에서 발생하는 다양한 조건들을 반영할 수 없다. 따라서 본 연구에서는 국내 터널환기 계획시, 양방향 차속의 불균등성 영향 분석을 목표로 하였으며, 차등차속의 영향을 환기계획에 고려하기 위하여서는 (1) '고속-지체' 시의 경우, 높은 차속에서의 매연의 허용기준을 적용할 필요가 있으며, (2) 교통량의 적절한 중방향비율의 선정 및 (3) 적절한 차등차속차이의 단계를 결정할 기준마련 등의 필요성이 제기된다. 그리고 본 연구에서는 국내 양방향 터널의 환기설계시, 동일차속과 차등차속을 적용한 경우의 환기설비 규모 차이를 비교 분석함을 목적으로 한다.