• Fire Science and Engineering
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• v.33 no.2
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• pp.1-8
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• 2019

This study was conducted to investigate the possibility of spontaneous ignition in Butadiene popcorn polymer, which is used as raw material and product in a chemical plant. A component analysis, thermogravimetric analysis, thermal stability analysis, spontaneous ignition point measurement and accelerated velocity calorimetric analysis were performed. As a result of analysis, various kinds of flammable components were measured and thermogravimetric analysis showed a weight loss of 95.6% in air and 89.2% in nitrogen. As a result of the thermal stability analysis, heat generation started at $88^{\circ}C$ in the air atmosphere, and the heat generation rate increased sharply in the vicinity of the natural ignition point ($220^{\circ}C$). The heat generation started at about $70^{\circ}C$ in nitrogen atmosphere, and the two exothermic peak values were observed up to $450^{\circ}C$. As a result of accelerated rate calorimetry, there was no exothermic phenomenon, and the lowest ignition temperature was $211.7^{\circ}C$ as a result of analysis of natural ignition point. Based on the results obtained from the thermal stability evaluation, it is considered that the possibility of inducing the thermal deformation of the column by the heat of reaction is sufficient.

• Journal of the Korean Society of Safety
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• v.26 no.3
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• pp.15-22
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• 2011

Explosion and fire cause about 30 reported industrial major accidents a year by ignition source which discharge of electrostatic generated to flammable gas, vapor, dust and mixtures. It brings economically and humanly very large loss that accident was caused by fire and explosion from electrostatic discharge. Thus, it is very important that electrostatic discharge energy is to be control below not to be igniting flammable mixtures. There are two kinds of analysis model for electrostatic discharge, human body model and machine model. Human body model is available the parameter of human's electrical equivalent that capacitance is 100 pF, resistance is $1.5k{\Omega}$. To simulate and visualize the electrostatic discharge from human body need a very expensive and high voltage simulator. In this paper, we measured the value of capacitance and resistance concerned with test materials and sizing of specimen and the value of charged voltage concerned with test specimen and distance to develop an electrostatic charge/discharge simulating tool for teaching with which concerned industrial employee and students. The result of experiments, we conformed that the minimum ignition energy of methane-oxygen mixtures meets well the equation $W=1/2CV^2$, and found out that the insulating material and sizing of equivalent value having human body mode are the poly ethylene of 200 mm and 300 mm of diameter. Developed electrostatic charge/discharge simulating tool has many merits; simple mechanism, low cost, no need of electric power and so on.

• Fire Science and Engineering
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• v.22 no.1
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• pp.84-92
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• 2008

Disclosed is a study related to the thermal characteristics of Pinus densiflora and Quercus dentate identifying the presence of any significant difference in the above trees, which are native to Young Dong Province of Korea, according to different regions of the trees such as branches, barks, living leaves and dead leaves. For this purpose, we have carried out a cone calorimeter test focusing on the variables such as mass loss, heat release, ignition time, flame holding time and concentrations of CO and $CO_2$. The results showed that the total mass loss was greatest in tree branches, whereas the ignition time of dead leaves was fastest both in Pinus densiflora and Quercus dantata. The flame holding times of dead leaves and barks were about $640{\sim}1,016s$ and the total heat release of dead leaves was around 60.1 $MJ/m^2$, twice the total heat release of living leaves. In addition, the maximum exhaust concentrations of CO and $CO_2$ in tree branches of Quercus dentata was 2.82 times higher than those of Pinus densiflora, respectively. From the foregoing, it was confirmed that there exist region-specific differential thermal characteristics in Pinus densiflora and Quercus dentata.

• Journal of Environmental Science International
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• v.9 no.2
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• pp.137-144
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• 2000

The observations on the seasonal fluctuation and distributional characteristic of organic matters on surface sediments and its origin were carried out at the 25 stations in Keogeum-sudo, southern coast of Korean Peninsula from February to October in 1993. I made an analysis on the environmental factors for surface sediments such as temperature, ignition loss, chemical oxygen demand, pheopigment, total sulphide, water content, mud content in grain size, COD/IL ratio and COD/sulphide ratio. The results are as follows ; 1) The range of temperature on the surface sediments was between 6.2${\circ}C$ and 24.6${\circ}C$. The highest mean temperatuer of mud was 24.0${\circ}C$ in summer, the lowest 6.6${\circ}C$ in winter. 2) Ignition loss(IL) fluctuated between 1.2% in winter and 16.8% in spring, that is to say, the seasons of increasing in temperature were very high ignition loss. 3) Chemical oxygen demand(COD) showed the highest mean value of 20.52 mg/g dry in summer within the range of 15/46~32.78 mg/g dry, while showed the lowest of 5.79 mg/g dry in winter within the range of 7.4~17.39 mg/g dry. 4) Pheopigment concentrations showed the highest mean value of 4.85 $\mu\textrm{g}$/g dry in autumn within the range of 0.84~9.21 $\mu\textrm{g}$/g dry, while it did the lowest mean value of 1.97 $\mu\textrm{g}$/g dry in summer within the range of 0.23~4.83 $\mu\textrm{g}$/g dry. 5) Total sulphide (H2S) fluctuated between no detect(ND) in spring, and 2.43 mg/g dry in sutumn. The highest mean value was 0.68 mg/g dry in sutumn, the lowest was 0.16 mg/g dry in spring. 6) Water content(WC) and mud content in grain size showed the mean value of 43.2% within the range of 26.5~59.7% and 91.0% within the range of 57.8~99.2%, respectively. 7) By the analytical results on the source of organic matter, it had been dumped from the seaweed farms in Keogeum-sudo coastal waters.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.329-345
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• 2016

In order to study the community structure and distribution pattern of macrobenthos in the subtidal area of Shia Sea between Haenam peninsula and Shinan-Jindo area at southwest coast of Korea, duplicate sediment samples were taken seasonally by van Veen grab (surface area, $0.1m^2$) from 49 stations between November 2001 and August 2002. The surface sediment facies were muddy sandy gravel near Mokpo-Gu channel, gravel in the Myoungrang channel with high tidal currents, and sandy muddy in the southern Uido area. Ignition loss in the sediment ranged from 0.5 to 1.5% with a mean of 0.6%. A total of 271 taxa were collected with a mean density of $166ind.\;m^{-2}$ and a mean biomass of $29.2g\;m^{-2}$. Polychaetes were dominant faunal group in terms of species richness and abundance, accounting for 34% and 40% of total species number and abundance, respectively. Molluscs accounted for 44% of biomass. Bio-Env analysis revealed that sediment composition and ignition loss affected the spatial distribution of subtidal macrobenthic community in the study area. Major dominant species were Photis longicaudata, Septifer keenae, Maldane cristata, Lumbrineris longifolia, Heteromastus filiformis and Coptothyris grayi. Based on cluster analysis, four station groups were classified. They were associated with sediment types. Bivalve, Striarca symmetrica, polychaetes, Glycera chirori, Heteromastus filiformis and decapod Latreutes planirostris were major contributing fauna in station group A, B, C, and D, respectively. These results suggest that macrobenthic community of the Shia Sea is normally influenced by sediment type and related ignition loss.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.355-364
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• 2020

This study was carried out to investigated changes in sediments in the eight weir sections of Nakdong River. Sediments were collected and analyzed for Grain Size, Ignition loss, Total Organic Carbon, Total Nitrogen, Total Phosphorus, and Meta. The upstream of the weir was found that fine-grained sediments have repeated increases and decreases. It was found that coarse-grained sediments were being maintained in the downstream part of the weir. The sediments Ignition Loss, Total Organic Carbon, Total Nitrogen, Total Phosphorus are strongly correlated with Grain Size, and these increased at the point where sediments are fine. In the case of metal, the concentration increased across the board, and the correlation with Grain Size, Ignition loss, Total Organic Carbon, Total Nitrogen, and Total Phosphorus was weak. Although there were some sections where fine-grained sediments, organic materials, nutrients, metals increased in the Nakdong River, the overall pollution level is considered weak.

• Journal of the Korean Professional Engineers Association
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• v.44 no.4
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• pp.39-43
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• 2011

To cope with recent high gas prices and global warming phenomenon, the latest gasoline engine technologies are focusing on direction injection, downsizing by turbo charging, variable compression ratio, controlled auto Ignition to enhance fuel efficiency and satisfy emission regulations. The variable valve train technology will be a basement for these innovative technologies in internal combustion engines and is supposed to play a key role to improve low thermal efficiency and pumping loss in gasoline engine caused by low compression ratio and throttled operation respectively.

• Journal of Life Science
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• v.8 no.5
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• pp.550-556
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• 1998

In order'to reduce loss of shrimp productivity by viral diseases on the cultured shrimp, we were develope the effective shrimp virus control system. Virus is inactivated by above 5 ppm of chloride and treatment of 50% fresh water. Mortality of infected shrimp is decreased by feeding of immunostimulants such as peptidoglycan and schizophyllan. Mg(OH)$_2$ was one of improvement agents which have best effect on pH, ignition loss(IL), chemical oxidation demand(COD) and total sulfide of water and sediment of shrimp farm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.35-41
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• 1982

Phaeophytin, COD, ignition loss and sulfide contents in the superficial bottom muds in Jinhae Bay, one of the most productive bays in the southern coastal waters of Korea, were measured in the summer season 1981 to investigate the eutrophication level and the origin of pollutants, Phaeophytin contents were $7.6-48.2{\mu}g/g$, COD 9.7-38.5 mg/g, ignition loss $8.1-14.2\%$ and sulfide 0.05-1.07 mg/g. Horizontal distributions in quantities of aforementioned four parameters were almost sane patterns; that is, the further from the mouth of the bay, the more quantities were found. The worst area was the western part of Gajo-do, where density of shellfish farms was the highest in the whole bay. COD and sulfide contents in the western part of Gajo-do were much more than maximum level of the eutrophicated zone, say 30 mg/g in COD and 0.2 mg/g in sulfide. Such great quantities of organic matters and sulfide in the innermost part of the bay would be mainly due to excrements from shellfishes and fouling organisms, but not owing to the influence of pollutants discharged from Masan, Jinhae harbour and its vicinity.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.191-196
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• 2015

In this study, physico-chemical properties and heavy metal contents of sediment samples were determined to characterize the current pollution levels of the sediments. Ignition loss of the samples obtained from outside of the harbor was relatively lower than that from the samples obtained inside of the harbor. Heavy metal pollution was not serious except Ni. Concentrations of Ni for J1, J3, and J4 exceeded 16 mg/kg. Thus, these areas were classified as lowest effect level according to Ontario sediment quality guidelines. Evaluation of sediments pollution using $I_{geo}$ and R resulted as non-pollution for all considered metals, which indicated that no outer pollutants entered in the Jeju outport harbor. However, drastic increase of Cu concentrations was observed. Its concentration obviously increased toward the inside of the outport harbor. Therefore, careful attention and plan for the protection and remediation of sediments is required to maintain the cleanness of the Jeju outport harbor.