• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.76-82
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• 2016

Recently, environmental sustainability of the transitional explosives and propellants is an issue of growing importance in energetic materials. For examples, ammonium perchlorate(AP) as an solid propellants oxidizer could create a poisonous gas and atmospheric pollutions, such as HCl. Among the several oxidizers, hydrazinium nitroformate(HNF) is an effective candidate substance for eco-friendly oxidizer, which has high density, pressure index, and less smog generating property during combustion for the thrust control system. This study was controlled the size distribution and shapes through various conditions. Length and diameter ratio(L/D) of crystals has below 1 : 3, and the particle size was two types of $200{\mu}m$ and $50{\mu}m$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.85-91
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• 2018

Recently, there have been a lot of casualties due to fires in high-rise buildings. The toxic gases and smokes generated by fires in high-rise buildings spread rapidly through the elevator shaft and stairwell, due to the stack effect, and can cause critical casualties. To reduce the number of casualties, smoke control systems have been introduced. Smoke control systems play an essential role in preventing the spread of smoke in high-rise buildings and securing the evacuation route. Also, in high-rise buildings, evacuation by an elevator is considered to be indispensable. However, the pressure field in the shaft is strongly disturbed when the elevator is moving and this can affect the performance of the smoke control system. Therefore, in this study, we experimentally and numerically analyzed the effect of elevator movement on the pressure difference between the vestibule and living room by building a model using the sandwich pressurization method based on the performance based design. To consider the leakage areas in high-rise buildings, e.g. the windows, fire door and elevator, the National Fire Safety Codes and area ratio were used. The elevator speed in the model building was varied between 20 m/s and 100 m/s corresponding to a real elevator speed of 7 m/s~17 m/s. As a result, the relationship between the pressure difference and elevator speed was found to be ${\Delta}P=40{\cdot}{\exp}$(-Ves /-104.7)-23.735. This result can be used to take into consideration the effect of elevator movement when designing smoke control systems.

• Journal of the Korean Institute of Gas
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• v.26 no.3
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• pp.27-37
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• 2022

With the recent increase in the spread of ESS (Electric Storage System), the damage to human life and property is also rapidly increasing due to continuous fires caused by ESS. In the manufacture of urethane sandwich panels used in ESS, it is necessary to improve the flame retardant performance. In this study, in order to realize the flame retardant properties of flexible polyurethane foam, the effect of the tissue density of the product due to the change of the isocyanate functional group parameter that changes the physical properties of the product on the fire performance was studied. The product was manufactured by changing the density of the urethane structure, and combustion performance tests, gas toxicity tests, and smoke density tests were performed. As a result, it was confirmed that the total amount of heat released had excellent performance when the isocyanate functional group was high, and had no correlation with the maximum heat release rate. When the value of the isocyanate functional group was 2.7 or more, the collapse of the shape could be prevented. In the gas hazard test, the performance was increased when the isocyanate functional group was relatively high, so a flame retardant for the Char system, which had a dense structure and easy to form a carbonized film, was added. confirmed to be. Therefore, as a result of this study, it is thought that it will be possible to lay the foundation for the development of a flame retardant to replace the cheap urethane sandwich panel used in the past.

• Clean Technology
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• v.24 no.1
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• pp.50-54
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• 2018

In this work, N-methyl-2-pyrrolidone (NMP) was added into diethylenetriamine (DETA) aqueous solution for high $CO_2$ loading via phase splitting of absorbents during $CO_2$ absorption. Immiscible two phases were formed in the range of more than 30 wt% of NMP in 2 M DETA + NMP + water absorbents because of low solubility of DETA-carbamate in NMP solution. As the composition of NMP in the absorbents increased, the difference of $CO_2$ loading between each phase increased and the volume of bottom phase decreased. In $CO_2$ absorption in packed column by 2 M DETA + NMP + water absorbents, the absorption rate decreased in the range of more than 40 wt% of NMP. It is due to the increasing of mass transfer resistance in liquid film of absorbents at the high concentration of NMP. DETA + NMP + water absorbent is expected as the promising one for reducing the regeneration energy of absorbents according to volume reduction of $CO_2-rich$ phase.

• Clean Technology
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• v.21 no.2
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• pp.124-129
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• 2015

The constant-volume method was used to determine the solubility of CO₂ in various physical absorbents such as DMPEG (dimethyl ether of polyethylene glycol), DEC (diethyl carbonate), DMC (dimethyl carbonate), and TAT (triacetin) in the total pressure range from 5 to 30 bar. The Peng-Robinson equation of state has been used to describe the equilibrium behavior of these mixtures. It was found that the solubility of absorbents was in the of DMPEG250 > TAT > DEC > DMC at the same temperature. Futhermore, the solubiity of blended absorbent of DMPEG250 and DEC is higher than that of DMPEG 250 alone. Therefore, blended absorbent of DMPEG250 and DEC is expected to be an effective and low cost absorbent for physical absorption in precombustion CO₂ capture.

• Fire Science and Engineering
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• v.24 no.3
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• pp.72-77
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• 2010

Honeycomb core structure with its excellent stiffness and strength is being utilized in many fields such as interior building material. Because it is inexpensive and renewable, honeycomb paper production is economically and environmentally helpful. However, the paper needs to be fireproofed because it is vulnerable to fire. In this study, we have undergone the performance evaluation process of the honeycomb paper which is widely used as interior material of a fire door and packing material. Four kinds of honeycomb (a honeycomb made of flame-resistant paper; a honeycomb attached with conventional flame-resistant film made in the laboratory; honeycomb impregnated with flame retardant; a honeycomb attached with flame-resistant film after impregnating fire retardant) were used in the study to compare the fire retardant performance. As a result, the honeycomb with impregnated flame retardant showed the highest performance. The flame-resistant film was effective in delaying the igniting time but had a negative effect on the rate of heat and smoke production.

• Tuberculosis and Respiratory Diseases
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• v.50 no.6
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• pp.693-703
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• 2001

Background : Smoking is the most important and consistent determinant of the development and progression of COPD(Ed Note : Define COPD). The fact that cigarette smokers develop a different type of COPD, chronic bronchitis and emphysema, with different clinical and pathological aspects, suggests that the development of COPD has a relationship with other smoking-associated factors beyond just a simple smoking history. The aim of this was to analyze the smoking habits and history of patients with COPD and to evaluate the development of different types of COPD according to patient's smoking habits. Method : To evaluate the differences in the smoking patterns of patients with chronic bronchitis and emphysema, a pulmonary function test was conducted, and the smoking history and patterns was obtained through a smoking history questionnaire by a direct personal interview from 333 male cigarette smokers diagnosed with COPD, in the Yeungnam university medical center(190 patients diagnosed with chronic bronchitis, 143 patients diagnosed with emphysema). Result : The patients with emphysema smoked earlier and had a higher smoking history(ie, more packyears, more total amounts of smoked cigarette, and more deep inhalation and longer duration of plain cigarette exposure) than those with chronic bronchitis. The depth of inhalation was also significantly higher in the emphysema patients after taking into account age, cumulative cigarette consumption and the type of cigarette smoked. Conclusion : Emphysema was more associated with the increasing degree of inhalation as assessed by the depth of inhalation. A high alveolar smoke exposure may be a significant risk factor for the development of emphysema.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.251-254
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• 2007

Veneer plate was painted by the treatment with ammonium salts such as ammonium chloride (AMCR), ammonium sulfate (AMSF), monoammonium phosphate (MAPP), and diammonium phosphate (DAPP) at room temperature. The flame retardancy of painted veneer plate was investigated. The painted veneer plate shows an increased $CO/CO_2$ over virgin veneer and it was supposed to affect the toxicity to different extents. But when the ammonium salts were used as the retardant for veneer, the flame retardancy was improved due to the painted ammonium salts in the veneers. Also, the veneer plates with ammonium sulfate and ammonium chloride showed both the lower total smoke release (TSR) and lower total smoke production (TSP) than that of virgin veneer.

• Archives of design research
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• v.18 no.4 s.62
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• pp.35-44
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• 2005

In the world, most of the metal technologists were as called as adornment artists than other field of industrial arts strongly industrial characters functional materials and manufacturing technology many used in the present age. In the study, one of adornments researched and material character analyzed about Art Clay Silver. The shrinkage rate of shape was about 0.24%. A shrinking phenomenon drying time thought of evaporation of water linking bonding agents and powders. After calcination of Art Clay Silver, the EDX used that just Ag 100% analyzed a result from the surface assay in the room temperature. A binder with powder in the room temperature considered to disappear, because it was been fume and smoke at high calcined temperature. A study showed when handicrafted necklaces make by these characteristic as using in difficult and delicated operations rather than naturally and beautifully expressive products.

• Journal of the Korean Society of Tobacco Science
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• v.10 no.1
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• pp.75-82
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• 1988

Cigarettes were made using a triple filter with several porous materials in its cavity. The removal effect of the adsorbents on carbon monoxide and hydrogen cyanide in cigarette smoke was investigated with the variation of their surface area and pore volume distributions. Several attempts were made to activated coconut shell based char under the fixed steam purging rate. 1. The specific surface area increased in number of micropore. It was found for transitional pore to have a little effect on the total surface area. 2. A Small amount of the particulate matter adsorbed on the adsorbents with transitional pores, Zeolite showed a little effect on the carbon monoxide adsorption though its small pore volume, but there was no significant difference in the adsorption capacity zeolite and the others. 3. In the adsorption for hydrogen cyanide as a vapor phase in cigarette smoke, the adsorption effect of the adsorbents increased remarkably with increasing their surface area and number of micropore. It was considered that the adsorbents with small pore volume like molecular seive 4A, in which the capillary diffusion of adsorbates could not be able, would not be effective for the adsorption of hydrogen cyanide.