• Fire Science and Engineering
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• v.23 no.4
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• pp.130-136
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• 2009

The present study has been performed to evaluate the reliability of the fire field model (FDS version 5.2) with yield rate concept of combustion products. The CO and smoke density predicted by FDS model was directly compared with measurement in a reduced scale ISO-9705 room. The GER (global equivalence ratio) concept was used to characterize the CO and smoke density with ventilation condition in the fire compartment. The FDS model tends to under-predict CO concentration and smoke density than those of measurement for the under-ventilated conditions. Also, the discrepancy between predicted and measured result increases as GER increases. In order to improve the reliability of the fire model for performance evaluation of fire safety, the fire model is necessary to be validated in various fire cases as well as develop detailed physical model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.11
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• pp.1644-1652
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• 2022

In the case of safety training where practical training is impossible due to risk problems, training contents using realistic media such as virtual reality or augmented reality are becoming a new alternative. In this paper, we propose a smoke modeling method that can be applied to safety-training contents implemented with realistic media technology. When an accident occurs in a hazardous area such as a petrochemical plant, visibility is not secured due to gas leakage and fire. In order to create such a situation, it is important to realistically express smoke. The proposed method is a smoke model implementation technique that can be effectively applied to the background of complex passages and devices such as petrochemical plants. In the proposed method, the smoke is expressed using volumetric rendering in the post-processing stage for the resulting image of scene rendering. Implementation results in the background of the factory show that the proposed method produces models that can express the smoke realistically.

• Fire Science and Engineering
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• v.10 no.4
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• pp.13-18
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• 1996

A general description of sprinkler activation time in compartment-fire-generated smoke layers is made. For calculation of the time hot layer temperature is obtained from two-layer zonal model and time constant of sprinkler is measured. Upper-layer thickness at the instant of sprinkler activation is also presented with changes of opening area. The output of the present study provide inputs for the interaction modeling of sprinkler spray and compartment fire environment, which simulates fire suppression phenomena. Futhermore, experiments are performed in mock-up with gasoline pool fire in order to evaluate the reliability of the model.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.123-128
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• 2007

To predict the fire and smoke hazards of rail car with a evacuation model is essential for achieving life safety of all passengers in the event of fire. Currently, more than 30 different evacuation models are available and expected increasing demand in high population density areas as a metro train station. This paper includes brief history of evacuation models and review some key factors of design egress scenario, these are pre-movement time, egress route, location of fire, overturned carriage, and configuration of rail car. Applying the egress model for rail passenger car, users need to confirm the model's ability of physiological, psychological responses effecting to pre-movement time of individual or crowd unit, representation of complexity of carriage layout, and evaluation of effects of smoke.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.9-15
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• 2009

In this study, the l/35 reduced-scale model experiment were conducted to investigate designed ventilation system performance at rescue station in tunnel fire. A model tunnel with 2 mm thick of steel, 10 m long, 0.19 m high and 0.26m was made by using Froude number scaling law. The cross-passages installing escape door at the center. were connected between accident tunnel and rescue tunnel. The n-heptane pool fire, $4cm\times4cm$, with heat release rate 698.97W were used as fire source. The fire source was located in the center and portal of accident tunnel as Worst case.. An operating ventilation system extracted smoke amount of 0.015 cms. The smoke temperature and carbon monoxide. concentration in cross-passage were measured to verify designed ventilation system. The results showed that, in center fire case without ventilation in accident tunnel, smoke did not propagated to rescue station. In portal tire case, smoke spreaded to rescue station without ventilation. But smoke did not propagated to rescue station with designed ventilation.

• Journal of Biosystems Engineering
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• v.15 no.4
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• pp.281-289
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• 1990

A frequency-domain, system-identification method using a binary multifrequency signal was developed to find the transfer function between smoke intensity and throttle position in a diesel engine. This paper describes the simulation study performed to test the identification method developed. With an assumption of a diesel operation in a limited region about the normal operating state, the linear theory was adopted. Because that air fuel ratio is one of the most important operating variables causing smoke production in diesel combustion, single-input and single-output model was adopted.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.6
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• pp.616-622
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• 2000

This paper concerns the application of smoke and fire spread to road tunnel fire problems. When a road tunnel is on fire. a fire protection system of road tunnel have to offer an adequate escape space to human. Therefore, this study carried out a simulation for predicting a spreading path of smoke and fire. The evolution of the flow field is simulated with the low Reynolds number k-$\varepsilon$ turbulent model and SIMPLE algorithm based on the finite volume method.

• Biomedical Science Letters
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• v.12 no.3
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• pp.281-287
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• 2006

Cigarette smoke causes atypical structure of pulmonary and oxidative damage. Therefore, we carried out to determine if exposure to cigarette smoke alters pulmonary structure and anti-oxidant related enzyme in a animal model, when natural product extracts using by Nebulizer. The rat were divided into four groups: $H_2O-treated$ (Control), natural product (Camellia sinensis) extracts-treated (CS), natural product extracts-treated with cigarette smoke-exposed (CS+SM) and cigarette smoke-expose (SM). All groups are similar to Control group in weight, but SM group is lower than the other groups. Microscopic image of the pulmonary structure in SM group showed deleterious alterations in the morphology, but the other groups are maintained in normal structure. In anti-oxidant related enzymes, SOD (superoxide dismutase) and catalase, SM group represents the lowest enzyme activity among all groups. But G6PD (glucose-6-phosphate dehydrogenase) and LPO (lipid peroxidation) is SM group represents the highest enzyme activity among all groups. These result indicate that the natural product extracts is an efficient tissue protective substance against smoke-induced lung injury.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.129-139
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• 2004

The several assumptions and design parameters to determine the ventilation rate in tunnel ventilation system were examined. In longitudinal ventilating tunnel, the ventilation rate has been determined by the critical velocity above which the smoke propagation to the upstream of ventilating air is prevented. Based upon the examination of assumptions and experimental results, we suggested the improved method to determine the critical velocity. In transverse ventilating tunnel, we found that the ventilation rate has been determined in accordance with the custom rather than fire-smoke dynamics such as the critical velocity in the longitudinal ventilating tunnel. It is because the ventilation rate in the transverse ventilation system has been determined by considering only the ventilation of contaminant by vehicle. To improve the ventilation design parameters based upon the fire-smoke dynamics, we conducted model tunnel fire experiments. From the experimental results, smoke propagating distance and smoke filling were suggested as the design parameter to determine the ventilation rate in transverse ventilating tunnel. And tunnels in Europe designed by the custom is found to have the dangerous nature in view of fire safety.

• Molecules and Cells
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• v.39 no.10
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• pp.728-733
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• 2016

Mesenchymal stem cells (MSCs) effectively reduce airway inflammation and regenerate the alveolus in cigarette- and elastase-induced chronic obstructive pulmonary disease (COPD) animal models. The effects of stem cells are thought to be paracrine and immune-modulatory because very few stem cells remain in the lung one day after their systemic injection, which has been demonstrated previously. In this report, we analyzed the gene expression profiles to compare mouse lungs with chronic exposure to cigarette smoke with non-exposed lungs. Gene expression profiling was also conducted in a mouse lung tissue with chronic exposure to cigarette smoke following the systemic injection of human cord blood-derived mesenchymal stem cells (hCB-MSCs). Globally, 834 genes were differentially expressed after systemic injection of hCB-MSCs. Seven and 21 genes, respectively, were up-and downregulated on days 1, 4, and 14 after HCB-MSC injection. The Hbb and Hba, genes with oxygen transport and antioxidant functions, were increased on days 1 and 14. A serine protease inhibitor was also increased at a similar time point after injection of hCB-MSCs. Gene Ontology analysis indicated that the levels of genes related to immune responses, metabolic processes, and blood vessel development were altered, indicating host responses after hCB-MSC injection. These gene expression changes suggest that MSCs induce a regeneration mechanism against COPD induced by cigarette smoke. These analyses provide basic data for understanding the regeneration mechanisms promoted by hCB-MSCs in cigarette smoke-induced COPD.