• Journal of Korean Society for Atmospheric Environment
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• v.14 no.E
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• pp.1-7
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• 1998

This paper presents an experimental study for understanding the indoor air quality in a room. A model room, which had a ceiling-mounted supply and a sidewall-mounted exhaust, was used to examine the effect of air exchange rate (AER) and contaminant source location (CSL) as a function of the elapsed time. A tracer gas method, using carbon monoxide tracer, gas analyzers, and a data acquisition system, was applied to study the ventilation air distribution and the tracer removal efficiency, so-called pollutant removal efficiency, in the model room. The experiment was composed of two parts; firstly the AER was varied to examine its effect on the ventilation air distribution and the ventilation effectiveness and secondly both AER and CSL were considered to determine their effect on the pollutant removal efficiency. It was found that the ventilation effectiveness in the model was proportional to AER but not linearly. It was also found that changing the CSL can improve the pollutant removal efficiency. In some cases, the efficiency improvement by increasing AER was achieved by simply changing CSL.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1307-1312
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• 2007

This experiments are performed to investigate the effect of ventilation velocity on a high pressure water mist fire suppression in subway train. The experiment is conducted in half scale modeled train of a steel-welled enclosure (8.0m*2.4m*2.1m). The ventilation velocity is controlled by the ventilation duct through an inverter in the range of 0 to 2 m/s. The coverage-radius and an injection angle of an high pressure water mist system are measured. The mist nozzle with 7-injection holes is operated with pressure 80 bar. The heptane pool fires are used. The fire extinguishment times and the temperatures are measured for the ventilation velocities. In conclusion, because the momentum of injected water mist is more dominant than that of ventilation air, the characteristics of water mist, the fire extinguishment times and the temperatures are affected very little by ventilation velocity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.10
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• pp.914-921
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• 2005

In this study, the 1/20 reduced-scale experiment using Froude scaling were conducted to investigate the effect of longitudinal ventilation velocity on the burning rate in tunnel fires. The methanol pool fires with heat release rate ranging from 2.02 kW to 6.15 kW and the n-heptane pool fires with heat release rate ranging from 2.23 kW to 15.6 kW were used. The burning rate of fuel was obtained by measuring the fuel mass at the load cell. The temperature distributions were observed by K-type thermocouples in order to investigate smoke movement. The ventilation velocity in the tested tunnel was controlled by inverter of the wind tunnel. In methanol pool fire, the increase in ventilation velocity reduces the burning rate. On the contrary in n-heptane pool fire, the increase in ventilation velocity induces large burning rate. The reason for above conflicting phenomena lies on the difference of burning rate. In methanol pool fire, the cooling effect outweighs the supply effect of oxygen to fire plume, and in n-heptane pool vice versa.

• Wind and Structures
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• v.19 no.2
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• pp.185-197
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• 2014

Ventilation and fire safety design in road tunnels are one of the most complex issues that need to be carefully considered and analysed in the designing stage of any potential upgrade of ventilation and other fire safety systems in tunnels. Placement road tunnels space has an important influence on fire safety, especially when considering the effect of adverse wind conditions that significantly influence ventilation characteristics. The appropriate analysis of fire and smoke control is almost impossible without the use of modern simulation tools (e.g., CFD) due to a large number of influential parameters and consequently extensive data. The impact of the strong wind is briefly presented in this paper in the case of a longitudinally ventilated road tunnel Kastelec, which is exposed to various severe wind conditions that significantly influence its fire safety. The possibility of using CFD simulations in the analysis of the tunnel placement in space terms negative effect of wind influence on the tunnel ventilation is clearly indicated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.7
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• pp.337-343
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• 2015

This paper investigates the ventilation characteristics in a two-dimensional underground network junction composed of four main lines interconnected by eight ramps. Simple one-dimensional models cannot be applied to network junctions since there are interferences of traffic piston effects in the main lines and at the ramps. A numerical algorithm was developed to analyze the pressure and airflow distributions iteratively. The Darcy-Weisbach equation was used to calculate the piston effects by traffic flows, and a Hardy Cross iteration was conducted for network analysis at the interconnected junction. The results show interesting ventilation characteristics and CO concentration distributions depending on system parameters such as vehicle speed, tunnel diameter, and other junction configurations.

• Journal of the Korean Society of Tobacco Science
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• v.6 no.1
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• pp.79-82
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• 1984

This study was carried out to investigate the effect of porous plug wrapping and perforated tipping paper on tip ventilation rate of cigarettes. The wider perforated width of tipping paper was and the more rows Perforation were given, the more increased the effort on the tip ventilation rate, and the high porous plug wrap also had a influence on the tip ventilation rate. Tip ventilation rate purposed would be obtained by adjusting the permeability of tipping papers with high porous plug wrap. To keep the cigarette quality uniform, the high porous plug wrapping paper and the tipping paper of small pore and many rows of perforation must be combined.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.3
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• pp.175-183
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• 2010

Windows are widely used for natural ventilation of the various buildings. Especially high level windows as a part of industrial ventilation systems, play a crucial role in natural ventilation. Compared to mechanical ventilation system, natural ventilation has the advantage of lower installation and operating costs. In general, high level windows for industrial buildings have three types; louver type, 45$^{\circ}$ open type and 90$^{\circ}$ open type. Based on previous studies, it was found that the louver type and 45$^{\circ}$ open type are very effective in reducing rainwater penetration, but they did not have enough ventilation efficiencies. Preliminary tests were performed with the various types of windows. It was found that a 90$^{\circ}$ open double layer type window was the best among those which tested in our preliminary tests. Simulated rain was used to estimate the amount of rain penetrated through windows and to observe the paths of rain penetration. Various 90$^{\circ}$ open windows were tested to find the windows with minimum rain penetration and maximum ventilation efficiency.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.1
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• pp.14-19
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• 2023

In summer, the natural ventilation performance for varying greenhouse width is very important in the glasshouses for year round cultivation. The effect of the side openings and greenhouse width on natural ventilation performance was analyzed by simulation. The necessary ventilation rate with different solar radiation transmittance increased significantly when the outside temperature grows higher. The necessary ventilation rate of 40% transmittance was about half of that of 90% transmittance. In consequence, shading effect on temperature control in greenhouse is significant in summer. When the total area of the openings for ventilation is constant, the maximum ventilation rate happens when the area of roof openings is equal to the area of side openings. This maximum ventilation rate is about 3 times of that of the greenhouse with roof openings and without side openings. Therefore, the side openings are advantageous to improve the natural ventilation in greenhouses. As the greenhouse width increases, the influence of side openings on the ventilation rate is becoming smaller. If the natural ventilation rate of the greenhouse with roof and side openings is to become double of that of the roof openings only, the width should be narrower than 38.4m for the Venlo type and 64m for Wide span type.

• Journal of Korean Academy of Nursing
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• v.31 no.1
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• pp.31-42
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• 2001

This study was done to evaluate the effect reducing artificial dead space on intubated children. Data were collected from July 1st, 1998 to August 31st, 1999. The subjects were selected from a pediatric intensive care unit of 'S' hospital and intubated with 3.5 mm or 4.5 mm endotracheal tube after open heart surgery. They were composed of 34 patients : 17 patients were assigned to the experimental group and the rest of them were placed in the control group. The artificial airway volume was minimized in the experimental group, and the control group maintained the artificial airway volume. ETCO2, PaCO2, SPO2 were measured as indicators of pulmonary ventilation. The tools of this study were GEM-Premier and Space-Lab patient monitors. The data were analyzed using the SPSS/PC+ program. The $\chi$2 -test was used to find general characteristics. The t-test was used to test the homogenety of the pulmonary ventilation status and mechanical ventilation setting before intervention between the two groups. Also, the paired t-test was used to examine the hypothesis. The results can be summerized as : 1. CO2 can be expelled effectively from the body in case artificial dead space was decreased. 2. As the artificial dead space was reduced, the difference between ETCO2 and PaCO2 was decreased, in other words pulmonary ventilation was improved. 3. If the artificial dead space occupied above 15 percent of tidal volume, the effect of CO2 was retention revealed in the body. 4. If the artificial dead space occupied below effect. Based on the results, the following is suggested to be applied practically : 1. A kind of the ventilator circuit acting artificial dead space should be removed from the intubated children with mechanical ventilaion. 2. The endotracheal tube should not be cut because extra-body space of the endotracheal tube did not have an effect on the dead space of the intubated children. Since the researcher could not cover this aspect in the study, they recommend the following. 1. The study should be extended to the other pulmonary disease patients for the effect of improving pulmonary ventilation. 2. Also, further studying with a more narrow interval in the extra-body space of the artificial airway will be able to explain the point of artificial dead space with proper ventilation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.3
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• pp.91-100
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• 1991

Since ventilation in livestock buildings is critical for indoor air quality, the first step in designing environmental control is to determine required ventilation rate. The purpose of the study was to suggest a conceptually new ventilation graph for determining minimum/maximum ventilation rate based on the conservation law of the thermal energy and mass in livestock buildings. PC-based programs coded with PASCAL language, [RVALUE] for overall thermal resistance of composite structural walls/ceilings, [POLYNOM] for coefficients values of animal's sensible heat equation were involved in developing a computer program, [VENTGRPH] for the determination of ventilation rate. It would be useful for design, for such a program would permit the designer to explore various design options and immediately, see the result in terms of its effect on minimum ventilation rates.