• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.1
• /
• pp.110-115
• /
• 2002

The tunnels built in recent years are equipped with traffic counters and pollution sensors (mostly, CO and Vl sensors). Utilizing these built-in sensors, it is possible to develop an algorithm to estimate the amount of pollutants exhausted from the each class of cars passing through the tunnel. These estimated data can be effectively utilized not only for ventilation control but also for designing ventilation facilities. The diffusion of pollutants in a tunnel can be described with one-dimensional diffusion-convection equation. This equation is approximated with interpolation functions and weighted residual method converting to adequate form for standard state estimate algorithms. With this converted equations, a least square optimization based algorithm is developed, whose outputs are the estimated amounts of pollutants emitted from each class of cars. In order to verify the feasibility of the developed algorithms, simulations are performed with the real data acquisitioned from the Tunnae tunnel located in Young-Dong highway in Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.15 no.3
• /
• pp.239-249
• /
• 2005

Ventilation effect is analyzed for boiler building with multiple heat sources. Air flow inside the boiler building is characterized as turbulent mixed convection. Analysis methodology is set up with two different $k-{\varepsilon}$ type models (standard $k-{\varepsilon}$, RNG $k-{\varepsilon}$). Two different cases with high and low outside temperature are analyzed. In case of high outside temperature condition, mixed convection is well realized inside the boiler building. With different upper louver opening rate, air flow is also well established and proper opening rate is found to meet design limit in case of low outside temperature condition. Difference of analysis results for two different turbulence models are not significant. Therefore, analysis methodology with simple $k-{\varepsilon}$ turbulence model is found to be reliable for the boiler building ventilation analysis. However, more simplified geometrical model is desired to expand its application.

• Fire Science and Engineering
• /
• v.22 no.5
• /
• pp.1-8
• /
• 2008

The study is to perform numerical analysis of train fire characteristics in an underground subway tunnel, depending the different locations of ventilation facility. To study the characteristics of train fire, two kinds of worst-case scenarios are selected, based on escape distance, escape time, and fire zone, and trends and thermal environments of tunnel are analyzed by changing the locations of ventilation facility for times. Fire characteristics is calculated by using FLUENT v.6.3.26, and turbulent flow is calculated by using the standard k-${\varepsilon}$ model. The numerical results show distribution of carbon monoxide concentration, temperature, and velocity. The results of this study will contribute to building the most suitable ventilation systems when designing subway stations and tunnels.

• 한국태양에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.115-123
• /
• 2011

Because buildings recently built have been highly insulated and highly airtight, it is impossible to emit toxic substances from interior finishing materials only by natural ventilation. Therefore, they cause indoor air pollution and it may threaten the user"s health such as atopic dermatitis, bronchial asthma and (allergic) rhinitis. Domestically, users spend indoors 80 percent of their time of a day. With the increased interest in indoor air quality, the introduction of forced ventilation system for new-built apartment buildings has been legislated. However, toxic substances from indoor are mostly below there commended standard approximately 23 months later. Thus, this study has assumed the status of the apartment buildings 23 months later through a simulation, regarded $CO_2$ as an exclusive indoor air pollution source. In the process of effectively eliminating the $CO_2$, this study has also been conducted on an operating plan that can provide superior performance from the energy side.

• Journal of the Korean Society of Safety
• /
• v.15 no.1
• /
• pp.72-79
• /
• 2000

In recent, occupational diseases in harmful working places become a social issue. It is the well-known fact that a respiration in polluted working places exert a serious effect on health of workers. Accordingly, the cutting off contaminants air originally is the best way to improve working environments. In these cases, ventilation systems should be essentially installed to dilute or exhaust the contaminated indoor air. In this study, we investigated the characteristics of ventilation system of the noxious gas in working indoor places with natural ventilation by using COMET. The numerical simulations were carried out the natural ventilation with two phase(air, dust). For turbulent flow, Reynolds stresses were closed by the standard $\kappa$-$\varepsilon$ model. The results are as follows ; 1) In the natural exhaust in the working place, the flows of the central region have a more rapid velocity vector than the right and left one. 2) Numerical results show that the distribution of contaminants concentration have greater influence on convection than the case of diffusion by government of velocity vectors. 3) To observe the velocity variation with distance, three location of distance are considered. As results, it shows that the velocity are 0.075(m/s) at y=5(m), 10(m) and mean concentration are raised 10.6% at y=5(m), 10(m). 4) We have presented the useful data for the adequate counterplan in the harmful working places by carrying out the various investigation of the natural ventilation.

• Journal of the Korea Society of Computer and Information
• /
• v.23 no.11
• /
• pp.143-149
• /
• 2018

The purpose of this study is to propose a management method to maintain the pleasant indoor air quality of the dental clinic by measuring and analyzing the indoor air quality of the dental clinic. The measurement was conducted in two rooms, a lobby where many residents stay in the reception room for waiting for medical treatment, and a VIP room where treatment activities are mainly performed. Measurement items are Temperature, Humidity, $CO_2$, CO, $NO_2$, $CH_2O$, VOC, $PM_{10}$ and measurement were taken on April 27, 2018. As a result of analyzing the temperature and humidity of the dental clinic, it was analyzed that the average indoor temperature was maintained at $25^{\circ}C$ and the humidity was kept at around 50%, maintaining proper indoor temperature and humidity environment. $CO_2$ was 855ppm in the VIP Room, which satisfied the maintenance standard. In the case of the lobby, it was analyzed to be 1,160ppm, which exceeded the maintenance standard and it is judged that the carbon dioxide generated by the respiration of the people staying in the lobby is the main reason. The mean concentration of formaldehyde in the VIP room was analyzed as $436{\mu}g/m^3$, exceeding the maintenance standard, and $2,100{\mu}g/m^3$ for the VOC exceeded the recommended standard. It was analyzed that the concentration was relatively higher due to the use of disinfectant and other drugs. The mean concentration of PM-10 in the lobby was analyzed as $65{\mu}g/m^3$ and it was analyzed that it satisfied the maintenance standard. To maintain a pleasant indoor air quality in a dental clinic it is necessary to minimize the effects of formaldehyde, VOC, $CO_2$ in the VIP rooms and lobby. For this purpose, the entire ventilation system and air purification system of the dental clinic should be installed. In case of the VIP room, local exhaust ventilation should be installed and workers should wear personal protective equipment.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.22 no.3
• /
• pp.323-335
• /
• 2020

In this study, a series of site measurement of particulate and gases pollutants at five tunnels were carried out along with case studies to review the suitability of the current road tunnel ventilation design standards. Previous studies by other researchers have shown that the ratios of the level of measurement to the standard were 27.9%, 1.6% and 3.4% for TSP, CO and NOx, respectively. Those measured in this site study shows even lower ratios; the ratios were 2.6%, 0.8% and 0.3%, for TSP, CO and NOx, respectively. The particle size analysis of TSP for the five tunnels shows that PM10 including tire wear and re-suspended road dust exceeded 20.4%. This implies that non-exhaust particulate matter must be taken into account, since the current design standards for the particulate matter (visibility) include only the engine emission. Based on the recent research results, for vehicle emission rate and slope-speed correction factors, revision of ventilation design standards for pollutants is required. WRA (PIARC) also emphasizes the necessity of the ventilation design standards for pollutants. In addition, enactment of a new road tunnel ventilation system operation standard or guideline is strongly recommended when considering the low operating rate of the ventilation system with jet-fans.

• Horticultural Science & Technology
• /
• v.34 no.6
• /
• pp.845-859
• /
• 2016

This study was conducted to examine the effect of nighttime ventilation and heating on changes in temperature and humidity, the occurrence of white rust, and growth of standard chrysanthemum (Dendranthema grandiflorum) 'Baekma' in a greenhouse. For the ventilation treatments, the mean nighttime humidity in the control greenhouse, which had a closed side window, was higher (94.5%), but the humidity in the natural and natural+fan ventilation treatments was lower (74.3% and 72.8%, respectively). The rate of occurrence of white rust at 34 days after treatment was 100, 98.3, 75.6, and 43.3% for the control, fan ventilation, natural ventilation, and natural+fan ventilation treatments, respectively. The number of infected leaves and telia were the lowest in the natural+fan ventilation treatment compared with the other treatments. The growth of the chrysanthemum 'Baekma' was significantly suppressed in the control because of the occurrence of white rust and high humidity, while plant height, number of leaves, stem diameter, and fresh weight were the greatest in the natural+fan ventilation treatment. For the heating treatments, the mean nighttime temperature of the control (RH 95% heating), which was heating and held at 95% humidity, was $18.4^{\circ}C$, while the temperature of the heating treatment, which was held at 70% relative humidity (RH 70% heating) was $25.8^{\circ}C$. The rate of occurrence of white rust (34.4%), number of infected leaves (0.9), and telia (1.0) were the lowest in the RH 70% heating treatment compared with the other heating conditions. Also, the RH 70% heating treatment showed the best growth in terms of plant height, stem diameter, number of leaves, and fresh weight. Therefore, the natural+fan ventilation and RH 70% heating treatments were effective for the control of white rust and the growth of standard chrysanthemum 'Baekma' in a greenhouse.

• Journal of Korean Academy of Nursing
• /
• v.21 no.3
• /
• pp.268-280
• /
• 1991

The nursing intervention for the prevention of the pulmonary complication and of the function lowering of pulmonary ventilation which emerge with high generation frequency during the nursing of operation patient is necessary for performing the qualitative nursing for operation patient. So, this researcher tried this study so as to obtain the data which can be utilized for the trial of nursing intervention, by grasping the effect that the deep breathing with Incentive Spirometer has on the function of pulmonary ventilation, analysing the factor to have influence on the function of pulmonary ventilation, and applying the effective method of deep breathing to the clinic. By making 42 patients who underwent the operation of upper abdomen after admitting G Hospital in Seoul from Mar. 7, 1991 to Apr.30, 1991 as the object, they were classified into the experiment group that the deep breathing was made with the use of Incentive Spiromenter and the comparison group that the deep breathing exercise was made without the use of Incentive Spirometer. And then, by measuring Tidal Volume and Forced Vital Capacity with Respirometer and $O_2$ Saturation with Pulse Oximeter at preoperation postoperation 24 hours, 72 hours, and 120 hours data were collected. The collected data were analyzed with of, average, standard deviation, x$^2$-test, t-test and ANOVA by SPSS. The result of this study is as follows : 1. As for the hypothesis that the function of pulmonary ventilation at postoperation 24 hours, 72 hours and 120 hours will be better in the experiment group that the deep breathing was made with the use of Incentive Spirometer, in comparison with the comparison group that deep breathing was made without the use of Incentive Spirometer, experiment group and comparison group didn't show the significant difference in Tidal Volume, Foreced Vital Capacity and $O_2$ Saturation at postoperation 24 hours and 72 hours. But experiment group and comparison group showed the significant difference in Tidal Volume at postoperation 120 hours (p＜0.01). So, this hypothesis was supported partially. 2. The variables that there were the significant differences about the function of pulmonary ventilation in experiment group at postoperation 24 hours stastically were smoking existence (p＜0.05), and the variables that there were not significant differences about the function of pulmonary ventilation were distinction of sex, age, anesthetic duration, smoking extent, body weight, surface area of body, existence of narcotic use, regular exercise existence, and past experience existence of respiratory disease. As above result, it appeared that the method of deep breathing with the use of the Incentive Spirometer is more effective for the function recovery of pulmonary ventilation, in comparison with the deep breathing without use of Incentive Spirometer and that smoking existence was the factor to have influence on the function of pulmonary ventilation. In the aspect of clinic, the trial of nursing intervention of deep breathing with use of Incentive Spirometer is expected. And, in the aspect of study, the study through various operative site patients about the effect of Incentive Spirometer use at the clinic will have to be confirmed.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1480-1486
• /
• 2011

After installation of platform screen door (PSD) in subway stations, particulate matters (PMs), which are originally ventilated through the platform, are accumulated inside the tunnel of the subway system. It deteriorates an air quality inside the tunnel. To ventilate the accumulated PMs inside the tunnel, the natural ventilator which are located inside the tunnel (namely, tunnel ventilation system) are used as only one circulation system. In addition, the installation of PSD can affect to the aerodynamic variations inside the tunnel, since the PSD system was not considered factor when the tunnel ventilation system was designed. However, the researches about the tunnel ventilation system have not been adequate. Therefore, this study is carried out with two objectives: 1) to measure the velocity of air current by the train-induced wind, when the train passes through the tunnel, and 2) to investigate the typical patterns of air current by quantitatively evaluating the characteristics of inflow/outflow of air current which passes through the natural ventilation system. This study can suggest the basic standard to newly design the tunnel of the subway system as well as the ventilation system.