• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.235-238
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• 2020

In the smart home era, fire safety is very important for human life and facility safety. Casualties and property damage from the fire would be a huge national loss. In this paper, we propose to predict the risk by determining the operating time of the fire detector according to the fire in the smart home. Among IoT fire detectors, heat detectors and smoke detectors, the risk can be predicted due to the difference in the operating time depending on the fire. Based on the results of this experiment, the ion-type smoke detector shows very fast characteristics, so it would be good to use the results in future fire prevention facility.

• Clean Technology
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• v.12 no.3
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• pp.175-181
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• 2006

The feasibility of the use of porous fossil diatoms for indoor air pollution control was investigated via the characterization of physical and chemical properties. The fossil diatoms were observed by SEM(Scanning Electron Microscope). Diatomite had well-distributed pores below 5 nm and relatively large surface area compare to sericite. However, no porosity in sericite was found. Results showed that diatomite had better performance than sericite in respect to porosity and large surface area. But diatomite which is thermally treated at $950^{\circ}C$ has no porosity and low surface area because of combustion of fossil diatoms or calcination of inorganic oxide at high temperature, and has poor adsorption capability of ammonia gas. In conclusion, porous diatomite has relatively high performance to adsorb noxious chemical compounds, such as ammonia gas and VOCs.

• Journal of Convergence for Information Technology
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• v.10 no.6
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• pp.77-86
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• 2020

A thin and porous non-flammable wiper was prepared by phosphorus acid solution treatment and subsequent oven annealing. The H₃PO₃ treatment improved flame retardancy of wiper paper to nonflammable level. Thermogravimetric analyses showed that residues increased to 50% at 700℃, which means this treatment helps dehydration of the cellulose chain and promotes the formation of char-like structures during the burning. FT-IR and X-ray photoelectron spectroscopy showed that some of the added H₃PO₃ could react with the functional groups of the cellulose chain. The reacted H₃PO₃ components promote dehydration of the cellulose components and the formation of a char-like structure and improve the flame retardancy of the wiper paper.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.712-718
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• 2019

A combustible producer gas composed of H₂, CO and CH₄ could be obtained by the thermal-chemical conversion of biomass. However, a large amount of particulate matters including tar generated causes the mal-function of turbines and engines or the fouling of pipelines. In this study, a wet scrubber using the soybean oil and bag filter were installed, and the removal efficiency was investigated. Hydrate limestone and wood char base activated carbon were pre-coated on the filter medium to prevent clogging of open pores. The removal efficiencies by the bag filter were 86 and 80% for the hydrated limestone and activated carbon coating, respectively. Overall, the collection when using a series of oil scrubbers and bag filters were 88%, while 83% for the filter coating material.

• Fire Science and Engineering
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• v.12 no.2
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• pp.29-42
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• 1998

The use of computer supported fire safety engineering calculations has grown significantly in recent years and will be increased rapidly. In this study, in order to examine for fire dynamics of the enclosed compartment with window glass(3mm, 4mm thickness) when the window glass breaks, we conducted numerical computer simulations about foam sofa fire with the zone type computer mode, FASTLite package(version 1.1.2) and the Berkeley algorithm for breaking window glass in a compartment fire, BREAK1 program (version 1.0). The analysis of the results in this paper shows that there are differences of fire dynamics between open-or enclosed-state compartment fire and the enclosed compartment fire with window glass breaking. It is also shown in this study that backdraft phenomenum occurs due to accumulated unburned combustible fuel when the glass of 4mm thickness breaks, and that temperature differences between the inner-and outer-surfaces of 3mm and 4mm thick glasses are appreciable. This study will help fire fighter to establish fire suppression or occupant's refuge strategies and fire safety engineer to enhance simulation techniques about the five dynamics of compartment fire.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.4
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• pp.357-364
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• 2016

Recently, the world faces the environmental problem such as air pollution due to harmful gas discharged from car and abnormal climate due to the green-house gases increased by the discharge of $CO_2$. Compressed Natural Gas (CNG), one of alternative for this problem, is less harmful, compared to the existing fossil fuel, as gaseous fuel, and less carbon in fuel ingredients and carbon dioxide generation rate relatively favorable more than the existing fuel. However, CNG fuel has the weakness of slow flame propagation speed and difficult fast burn. On the other hand, hydrogen does not include carbon in fuel ingredients, and does not discharge harmful gas such as CO and HC. Moreover, it has strength of quick burning velocity and ignition is possible with small ignition energy source and it's has wide Lean Flammability Limit. If using this hydrogen with CNG fuel, the characteristics of output and discharge gas is improved by the mixer's burning velocity improved, and, at the same time, is possible to have stable lean combustion with the reduction of $CO_2$ expected. Therefore, this research tries to identify the characteristics of engine and emission gas when mixing CNG fuel and hydrogen in each portion and burning them in spark igniting engine, and grasp the combustion stability and emission gas characteristics according and use it as the basic data of hydrogen-CNG premixed engine.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.4
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• pp.412-420
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• 2016

Effect of $H_2S$ on reactivity of oxygen carrier was measured and discussed using fluidized bed reactor and SDN70 oxygen carrier. We could get 100% of fuel conversion and $CO_2$ selectivity even though $H_2S$ containing simulated syngas was used as fuel for reduction. Absorbed sulfur was released during oxidation and $N_2$ purge step after oxidation as $SO_2$ form. We could get 100% of fuel conversion and $CO_2$ selectivity during cyclic reduction-oxidation tests up to 10th cycle. However, only 6~7% of sulfur can be removed during oxidation and $N_2$ purge step and 93~94% of sulfur was accumulated in the oxygen carrier. Therefore we could conclude that total removal of sulfur was not possible. $SO_2$ emission during oxidation decreased as the number of cycle increased. Therefore we could expect that the reactivity of oxygen carrier will be decreased with time.

• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.32-35
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• 2011

Experimental studies were carried out in an explosion chamber to investigate the influences of multiple cylinder obstacles on local flame propagation. The chamber dimension is 235 mm in height with a $1,000{\times}950\;mm^2$ rectangular cross section and a large vent area of $1,000{\times}320\;mm^2$. Multiple cylinder bars with obstruction ratio of 30% were used. In order to examine the interaction between the propagating flames and the obstacles, temporally resolved flame front images were recorded by a high speed video camera. The propagation behaviour of local flame fronts around the left obstacle was analyzed in terms of two different methods such as the incremental burnt area divided by the flame front length and the average of the local propagation velocity determined at each point along the flame front. It was found that two methods give good consistency.

• Journal of The Association for Neo Medicine
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• v.1 no.1
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• pp.103-113
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• 1996

It is thought that the quantity and quality of the heat stimulation and the mechanism of heating process are important to understand the moxa-combustion. In order to get the basic data on the effective moxa-combustion method, combustion temperature changes (average temperature, peak temperature, average gradient temperature and maximum gradient temperature) of the heating period were measured respectively by the density of moxa material. For the experiment, samples of $300mg/0.26cm^3$ , $400mg/0.26cm^3$ and $500mg/0.26cm^3$ of moxa material were molded in a conical mold with each 10mm in diameter and height. 1. The average temperature and peak temperature of heating period on the moxa-combustion showed higher in the $400mg/0.26cm^3$ and $300mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. 2. The average gradient temperature of heating period on the moxa-combustion rose quickly in the $300mg/0.26cm^3$, $400mg/0.26cm^3$ and $500mg/0.26cm^3$ in that order and the maximum gradient temperature rose more quickly in the $300mg/0.26cm^3$ and $400mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. According to the above results, it is concluded that the density of moxa material is (the) more important (factor) than the weight or volume of moxa material on the combustion temperature changes of the heating period for the evaluation of the quality and quantity of moxa-combustion.

• Journal of computational fluids engineering
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• v.17 no.3
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• pp.75-86
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• 2012

We developed a preliminary CFD analysis methodology to predict a pressure build up due to hydrogen flame acceleration in the APR1400 IRWST on the basis of CFD analysis results for test data of hydrogen flame acceleration in a scaled-down test facility performed by Korea Atomic Energy Research Institute. We found out that ANSYS CFX-13 with a combustion model of the so-called turbulent flame closure and a model constant of A = 5.0, a grid model with a hexahedral cell length of 5.0 mm, and a time step size of $1.0{\times}10^{-5}$ s can be a useful tool to predict the pressure build up due to the hydrogen flame acceleration in the test results. Through the comparison of the simulated results with the test results, we found out that the proposed CFD analysis methodology enables us to predict the peak pressure within an error range of about ${\pm}29%$ for the hydrogen concentration of 19.5%. However, the error ranges of the peak pressure for the hydrogen concentration of 15.4% and 18.6% were about 66% and 51%, respectively. To reduce the error ranges in case of the hydrogen concentration of 15.4% and 18.6%, some uncertainties of the test conditions should be clarified. In addition, an investigation for a possibility of flame extinction in the test results should be performed.