• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.42-45
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• 2006

A new and reusable energy source is water-treatment sludges. There is a significant need for understanding the characteristics of sludge combustion related to improving efficiency and ensuring the safety of this new energy source. Because sludges are composed of solids and gas mixture, the combustion of the mixture may become quite complex. Not only decomposition of conventional organic elements but also dust explosion may be important during the process of converting sludges into a new and safe form of energy. Sludge combustion mainly involves hydrogen, methane, hydro carbons, carbon, and organic particles. Dust explosion during the gasification stage may depend on the surrounding temperature and the composition of gases. The uncertainty in the explosive behavior of energetic source is noted in this work. We study the explosion characteristics of sludge combustion while the reusability of sewage sludges as a new form of energy is also investigated.

• Journal of the Ergonomics Society of Korea
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• v.20 no.3
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• pp.61-76
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• 2001

This study is for analyzing the explosion accidents in the tunnels, roads, subways, streets and various kinds of building construction area with the use of Fault Tree Analysis(FTA). based on the police Department and Guns & Explosives Safety Technology Association's researching materials. the explosion accidents have been investigated and analyzed between 1988 and 1977. As the result, we can find out that the majority of the explosion accidents in Korea is the accidents by flown stones(45.7%), like in Japan. So we make the research chart which is needed for analyzing the explosion accident, and then analyze these accidents systematically. using the investigation codes of the industrial accidents. After that, the FTA was performed on the accidents by flown stones. They result fromm non-observance of the safety rules, and lees knowledge of the safety and so on. Moreover several causes are combined and then the accidents are apt to happen. So according to the results of this study, for the protection of the explosion accidents, the specialized safety education is badly needed and the enough investigation of the places before the work along with the management for safety in working must be planned.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.5
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• pp.568-576
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• 2017

With an increase in the usage of LNG, there is a heightened interest about its safety aspects regarding the explosion of LNG carrier tank. The need for a cryogenic explosion-proof camera has increased. The camera has to work in cryogenic environment (below $-160^{\circ}C$) in LNG carrier. This study conducted design and heat transfer analysis of cryogenic camera to secure working time in limitation of heat source. The design with gap width of double pane windows was conducted based on simple vertical cavity model to insulate from cryogenic environment. The optimal gap width was 12.5 mm. For effective analysis considering convection within the camera, equivalent thermal conductivity method was adopted with ABAQUS. The working time of the camera predicted was over 10 h at warm-start condition. In cold-start condition, it required about 5 h of pre-warming time to work. The results of analysis were compared with the ones of the actual cryogenic test.

• Journal of the Korean Society of Safety
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• v.38 no.6
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• pp.26-35
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• 2023

Sparks cause most fire and explosion accidents in the manufacturing industry during hot work, which ignites surrounding combustible materials. Such incidents lead to high casualties due to suffocation from toxic gases and lack of evacuation. Therefore, the government recently enacted and revised 'The Occupational Safety and Health Act' to prevent fires and explosions at work sites, incorporating legal standards for fire observers, which are important in preventing accidents and the spread of fire during hot work. However, there are notable shortcomings in conducting professional cause analysis of these accidents and in aligning them with advanced foreign legal standards. Additionally, there is a lack of literature review reflecting the manufacturing industry characteristics. Despite the recent enactment and revision of legal standards, gathering sufficient opinions and professional reviews remains insufficient. To address these gaps, interviews were conducted with safety and health workers, analyzing recent fire and explosion causes in domestic manufacturing industries, and reviewing both domestic and international legal standards. Conclusively, proposed improvement measures were centered on the professionalization of fire observer education, enhancing their roles and authority realistically, and improving fire observer placement and operation standards. Consequently, additional 'Occupational Safety and Health Act' standards are necessary for fire observer education and defining the government's role. Second, precise legal standards outlining the role and authority of fire observers are required. Third tailored fire observer arrangements and management standards appropriate for varying work characteristics and company sizes are required. This study emphasizes the importance of supplementing relevant legal standards to prevent fire accidents in the manufacturing industry.

• Journal of Powder Materials
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• v.10 no.3
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• pp.151-156
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• 2003

In the present work some properties of nanopowders and possible areas of their applications are discussed. Main attention is paid to the use of nanodispersed powders (NDP) in new materials production technologies.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.9
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• pp.841-849
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• 2013

Workers engaged in construction works have been exposed to high levels of noise during their work in tunnels. Noise is one of the major health hazards for employees working in construction sites. The aim of this study is to evaluate the noise levels generating from tunneling equipments such as jumbo drills, backhoes, payloaders, shotcrete machines and service cars. Explosion and turbo fan noises were also monitored. A high precision sound level meter was introduced for measuring LAeq, LAFmax, LAFmin and LCpeak noises in 5 tunneling work sites that were located in Seoul, Kyunggi-do and Kangwon-do areas with NATM and shield methods. The highest noise was recorded by explosion(151.9 dB LCpeak) followed by jumbo drills of higher than 110 dB(A) LAeq. Backhoe normally generated 90~110 dB(A) LAeq while breaking work of rock showed additional around 5~15 dB(A). Noise exposure levels for payloader and shotcrete machine scored more than 90 dB(A) which might be a source of noise-induced hearing loss. Additional research in revealing noise levels from construction equipments operating in tunneling works may enhance the protection of workers who exposed to noise primarily at the sites.

• Journal of Powder Materials
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• v.27 no.6
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• pp.449-457
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• 2020

Iron and copper are practically immiscible in the equilibrium state, even though their atomic radii are similar. As non-equilibrium solid solutions, the metastable Fe-Cu alloys can be synthesized using special methods, such as rapid quenching, vapor deposition, sputtering, ion-beam mixing, and mechanical alloying. The complexity of these methods (multiple steps, low productivity, high cost, and non-eco-friendliness) is a hinderance for their industrial applications. Electrical explosion of wire (EEW) is a well-known and effective method for the synthesis of metallic and alloy nanoparticles, and fabrication using the EEW is a simple and economic process. Therefore, it can be potentially employed to circumvent this problem. In this work, we propose the synthesis of Fe-Cu nanoparticles using EEW in a suitable solution. The powder shape, size distribution, and alloying state are analyzed and discussed according to the conditions of the EEW.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.139-143
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• 2015

We describe a survey of nearby core-collapse supernova (SN) explosion sites using integral field spectroscopy (IFS) techniques, which is an extension of the work described in Kuncarayakti et al. (2013). The project aims to constrain SN progenitor properties based on the study of the immediate environment of the SN. The stellar populations present at the SN explosion sites are studied by means of integral field spectroscopy, which enables the acquisition of both spatial and spectral information of the object simultaneously. The spectrum of the SN parent stellar population gives an estimate of its age and metallicity. With this information, the initial mass and metallicity of the once coeval SN progenitor star are derived. While the survey is mostly done in optical, the additional utilization of near-infrared integral field spectroscopy assisted with adaptive optics (AO) enables us to examine the explosion sites in high spatial detail, down to a few parsecs. This work is being carried out using multiple 2-8 m class telescopes equipped with integral field spectrographs in Chile and Hawaii.

• Journal of the Korean Institute of Gas
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• v.10 no.1 s.30
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• pp.48-55
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• 2006

In order to establish the comprehensively, quantitatively predictable program to the fire and explosion accidents in the urban gas system, and to set up domestic criteria of societal risk, the collected urban gas accident data have been deeply analyzed. The Poisson probability distribution functions with t=5 for the database of the gas accidents in recent 11 year shows that 'careless work-explosion-pipeline' item has the lowest frequency, whereas 'joint loosening & erosion-release-pipeline' item has the highest frequency. And thus the proper counteractions must be carried out. The further works requires setting up successive database on the fire and explosion accidents systematically to obtain reliable analyses.

• Journal of Forest and Environmental Science
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• v.32 no.3
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• pp.253-261
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• 2016

Xanthoceras sorbifolia seed coat (XSSC) is a processing residue of the bioenergy crop. This work aimed to evaluate the applicability of using the steam explosion to modify the residue for dye biosorption from aqueous solutions by using methylene blue as a model cationic dye. Equilibrium, kinetic and thermodynamic parameters for the biosorption of methylene blue on the steam-exploded XSSC (SE-XSSC) were evaluated. The kinetic data followed the pseudo-second-order model, and the rate-limiting step was the chemical adsorption. Intraparticle diffusion was one of the rate-controlling factors. The equilibrium data agreed well with the Langmuir isotherm, and the biosorption was favorable. The steam-explosion pretreatment strongly affected the biosorption in some respects. It reduced the adsorption rate constant and the initial sorption rate of the pseudo-second-order model. It enhanced the adsorption capacity of methylene blue at higher temperatures while reduced the capacity at lower ones. It changed the biosorption from an exothermic process driven by both the enthalpy and the entropy to an endothermic one driven by entropy only. It increased the surface area and decreased the pH point of zero charge of the biomass. Compared with the native XSSC, SE-XSSC is preferable to MB biosorption from warmer dye effluents.