• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.20-31
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• 2018

There was an amazing growth in the korean shipbuilding industry considering the industrial magnitude and the technical level. On the contrary of the growth, there are a number of accidents in the shipbuilding yard. According to the statistic data of the industrial accident in the last 7 years, the number of accidental fatalities in shipbuilding industries are 1.48 ‱ which are over more than doubles of the average in the Korean industries, 0.66 ‱. Thus, through an accident investigation of fire and explosion case during painting work in the tank of the crude oil carrier, it have been tried to diagnose actual conditions in the shipbuilding yards.

• Fire Science and Engineering
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• v.20 no.1 s.61
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• pp.6-14
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• 2006

The data of city gas accidents has been collected and analysed for not only predictions of the fire and explosion accidents but also the criteria of societal risk. The accidents of the recent 11 years have been broken up into such 3 groups roughly as "release", "explosion", "fire" d 16 groups in detail. Owing to the Poisson probability distribution functions, 'careless work-explosion-pipeline' and 'joint loosening & erosion-release-pipeline' items respectively have turned out to record the lowest and most frequency among the recent 11-years accidents. And thus the proper counteractions must be carried out. In order to assess the societal risks tendency of the fatal gas accidents and set the more obvious safety policies up, the D. O. Hogon equation and the regression method has been used to range the acceptable range in the F-N curve of the cumulative casualties. The further works requires setting up successive database on the fire and explosion accidents systematically to obtain reliable analyses. Also the standard codification will be demanded.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.30-36
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• 1993

Wood chips of oak (Quercus mongolica) and larch (Larix leptolepis) were treated with a relatively low pressure steam(10~20 kg/$cm^2$) for 10~20 min (first-stage),and then increased pressure up to 30kg/$cm^2$ for 30 second (second-stage), and steam pressure was released intentionally to air. Main components of exploded wood were separated with 1% NaOH and hot water-methanol. In this work, the more effective low pressure explosion condition and separation method of wood main component were investigated. The results can be summarized as follows; 1. The yields of exploded wood were generally decreased with increasing steam pressure and reaction time. 2. The proper condition of steam explosion in low pressure for the separation of wood main components was 15kg/$cm^2$-10 min, in oak wood and 20kg/$cm^2$-10 min., then 30kg/$cm^2$-0.5 min, in larch wood. 3. The 23% of elude hemicellulose was obtained from the exploded oak wood which was treated with optimal condition. 4. In the case of hot water-methanol extraction, the ratio of delignification was 14~23% in the exploded larch wood and 42~55% in the exploded oak wood. 5. The methanol was more effective than 1% sodium hydroxide solution for extraction of lignin from exploded wood.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.12-19
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• 2015

$CO_2$ is non-flammable, non-toxic gas and not cause of chemical explosion. However, various impurities and some oxides can be included in the captured $CO_2$ inevitably. While the $CO_2$ gas was temporarily stored, the pressure in a storage tank would be reached above 100bar. Therefore, the tank could occur a physical explosion due to the corrosion of vessel or uncertainty. Evaluating the intensity of explosion can be calculated by the TNT equivalent method generally used. To describe the physical explosion, it is assumed that the capacity of a $CO_2$ temporary container is about 100 tons. In this work, physical explosion damage in a $CO_2$ storage tank is estimated by using the Hopkinson's scaling law and the injury effect of human body caused by the explosion is assessed by the probit model.

• Journal of the Korea Institute of Building Construction
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• v.10 no.3
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• pp.99-111
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• 2010

In recent years, the number of high-rise building construction projects has grown, and the number of construction safety accidents has also been increasing. Therefore, the objective of this study is to propose plans to prevent accidents by systematically organizing accident principles and developing a tree diagram for the process of safety accidents that occur in the construction industry. This study aims to show the diverse characteristics of construction accidents based on KOSHA's annual reports on safety accidents(burial, conflagration, explosion, burn) from 1993 to 2009. To achieve these objectives, in this study we first examined the risk factors for burial, conflagration, explosion, and burn. We then systematically organized the classification viewpoint of accident causes, and suggested a methodology for the rationalization of safety management through an analysis of the primary causes of accidents by work type. The results of this study based on this methodology can be divided into three areas: 1)the types of facilities were divided into 43 categories by analyzing the information of KOSHA's annual reports; 2)the causes of burial, conflagration, explosion, and burn were divided into 63types; 3)the types of work were divided into 29 categories.

• Journal of the Korean Wood Science and Technology
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• v.17 no.4
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• pp.57-69
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• 1989

Roughage feeds were produced from Hyun-aspen (Populus alba $\times$ p. glandulosa) by steaming-defibration and steaming-explosion. The objectives of this work were to find proper conditions for the treatment of Hyun-aspen by analyzing the compositional change and digestibility and to investigate the change of physical properties of exploded woods. The results of this work were as follows; 1. The method of steaming-de fibration gave the best producing rate of feedstuffs when the chips were steamed (9kg/$cm^2$ under the pressure) for 10 minutes. The yield and the digestibility of feedstuffs were 84.2% and 38.1%, respectively. It is the merit of this method that feedstuffs manufactured by this method was uniformity in particle size, and facilities of fiberboard factory could be used directly, 2. For defibration of the chip by explosion, the proper condition was steamed under the pressure (20kg/$cm^2$) for 4 minutes. The yield and the digestibility of feedstuffs were 93.4% and 68.1%, respectively. The feedstuffs produced under these conditions had higher nutritional quality than rice straw and this method was considered as the best for making feedstuffs from Hyun-aspen chip. But it is defect that exploded feedstuffs was ununiformity in particle size and had unique odor. The physical properties of the feedstuffs were investigated by a light microscope and a TEM. The feedstuffs produced under the low pressure (20 kg/$cm^2$) still maintained the structure of fibers. However, the feedstuffs produced under the high pressure (28 kg/$cm^2$) resulted in higher de fib ration than these prepared under the low pressure. The highly defibrated feedstuffs recombined with solublized lignin. The crystallinity of feedstuffs was increased by 10% and micelle width increased double after treatment.

• Journal of the Korean Institute of Gas
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• v.14 no.2
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• pp.15-21
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• 2010

The demand of gas as an eco-friendly energy source has being increased. With increasing the LPG demand, the number of LPG filling station. In this work, the influence on over-pressure caused by Vapor Cloud Explosion in gas station was calculated by using the Hopkinson's scaling law and injury effect by the accident to a human body was estimated by applying the probit model. As a result of the injury estimation conducted by using the probit model for leakage 10% of 20ton storage tank. The distances from LPG station for death and tympanum rupture are 36.5 and 290 meters, respectively.

• Journal of Powder Materials
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• v.23 no.4
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• pp.317-324
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• 2016

Tin is one of the most promising anode materials for next-generation lithium-ion batteries with a high energy density. However, the commercialization of tin-based anodes is still hindered due to the large volume change (over 260%) upon lithiation/delithiation cycling. To solve the problem, many efforts have been focused on enhancing structural stability of tin particles in electrodes. In this work, we synthesize tin nano-powders with an amorphous carbon layer on the surface and surroundings of the powder by electrical wire explosion in alcohol-based liquid media at room temperature. The morphology and microstructures of the powders are characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The electrochemical properties of the powder for use as an anode material for lithium-ion battery are evaluated by cyclic voltammetry and a galvanometric discharge-charge method. It is shown that the carbon-coated tin nano-powders prepared in hexanol media exhibit a high initial charge specific capacity of 902 mAh/g and a high capacity retention of 89% after 50 cycles.

• Journal of Magnetics
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• v.16 no.4
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• pp.435-439
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• 2011

In this work, we prepared Fe-Ni alloy nanopowders by wire electrical explosion in deionized water and ethanol. Particles size and morphology of the as-synthesized nanoparticles prepared in water and ethanol were observed by transmission electron microscopy. In both cases, the as-synthesized nanoparticles were in nearly spherical shape and their size distribution was broad. The particles prepared in the water were in core-shell structure due to the oxidation of Fe element. X-ray diffraction was used to analyze the phase of the nanopowders. It showed that the nanopowders prepared in water had ${\gamma}$-Fe-Ni solid solution and FeO phase. The samples obtained in ethanol were in two phases of Fe-Ni solid solution, ${\gamma}$-Fe-Ni and ${\alpha}$-Fe-Ni. Bulk samples were made from the as-synthesized nanopowders by spark plasma sintering at $1000^{\circ}C$ for 10 min. Structure of the bulk sample was observed by scanning electron microscope. Magnetic properties of the as-synthesized nanopowders and the bulk samples were investigated by vibrating sample magnetometer. The hysteresis loop of the assynthesized nanopowders and the sintered bulk samples revealed a ferromagnetic characteristic.

• Nuclear Engineering and Technology
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• v.41 no.9
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• pp.1215-1222
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• 2009

The present work pertains to a research program to study Molten Fuel-Coolant Interactions (MFCI), which may occur in a nuclear power plant during a hypothetical severe accident. Dynamics of the hot liquid (melt) droplet and the volatile liquid (coolant) were investigated in the MISTEE (Micro-Interactions in Steam Explosion Experiments) facility by performing well-controlled, externally triggered, single-droplet experiments, using a high-speed visualization system with synchronized digital cinematography and continuous X-ray radiography. The current study is concerned with the MISTEE-NCG test campaign, in which a considerable amount of non-condensable gases (NCG) are present in the film that enfolds the molten droplet. The SHARP images for the MISTEE-NCG tests were analyzed and special attention was given to the morphology (aspect ratio) and dynamics of the air/ vapor bubble, as well as the melt drop preconditioning. Energetics of the vapor explosion (conversion ratio) were also evaluated. The MISTEE-NCG tests showed two main aspects when compared to the MISTEE test series (without entrapped air). First, analysis showed that the melt preconditioning still strongly depends on the coolant subcooling. Second, in respect to the energetics, the tests consistently showed a reduced conversion ratio compared to that of the MISTEE test series.