• Journal of Environmental Health Sciences
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• v.46 no.6
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• pp.726-734
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• 2020

Objectives: The aim of this study was to analyze and classify the characteristics of potential damage from hazardous chemical accidents in 229 administrative units in South Korea by reflecting the social and environmental characteristics of areas where chemical accidents can occur. Methods: A number of indicators were selected through preceding studies. Factor analysis was performed on selected indicators to derive factors, and cluster analysis was performed based on the factor scores. Results: As a result of the cluster analysis, 229 administrative units were divided into three clusters, and it was confirmed that each cluster had its own characteristics. Conclusions: The first cluster, "areas at risk of accident occurrence and spread of damage" was a type with a high potential for accident damage and a high density of hazardous facilities. The second cluster, "Urban infrastructure damage hazard areas" appeared to be a cluster with high urban development characteristics. Finally, the third cluster 'Urban and environmental damage hazard areas' appeared to be a cluster with an excellent natural environment. This study went further from the qualitative discussion related to existing chemical accidents to identify and respond to accident damage by reflecting the social and environmental characteristics of the region. Distinct from the previous studies related to the causes of accidents and the response system, it is meaningful to conduct empirical research focusing on the affected areas by analyzing the possibility of accident damage in reflection of the social and environmental characteristics of the community.

• Journal of the Korean Magnetic Resonance Society
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• v.11 no.2
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• pp.115-121
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• 2007

A new quantitative analysis of chloride by the HERETIC NMR method which does not need internal or external references was described. The results showed that the use of HERETIC peak corresponding $500\;{\mu}g/mL$ of chloride calibration showed less than 4 % standard deviations from 50 to $5000\;{\mu}g/mL$ range of chloride concentrations.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.1-8
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• 2020

Mobile elevating work platforms (MEWPs) consist of a work platform, extending structure, and chassis, and are used to move persons to working positions. MEWPs are useful but are composed of pieces of equipment, and accidents do occur owing to equipment defects. Among these defects, accidents caused by the fracture of bolts fixed to the extension structure and swing system are increasing. This paper presents a failure analysis of the fixing bolts of MEWP. Standard procedure for failure analysis was employed in this investigation. Visual inspection, chemical analysis, tensile strength measurement, microstructural characterization, fractography analysis by Optical Microscope(OM) and Scanning Electron Microscopy(SEM), and finite element analysis (FEA) were used to analyze the failure of the fixing bolts. Using this failure analysis approach, we found the root cause of failure and proposed a means for solving this type of failure in the future. First, the chemical composition of the fixing bolt is obtained by a spectroscopy chemical analysis method, which determined that the chemical composition matched the required standard. The tensile test showed that the tensile and yield strengths were within the required capacity. The stress analysis was carried out at five different boom angles, and it was determined that the fixing bolt of MEWP can withstand the loads at all the boom angles. The outcomes of the fatigue analysis revealed that the fixing bolt fails before reaching the design requirements. The results of the fatigue analysis showed primarily that the failure of the fixing bolt was due to fatigue. A visual inspection of the fractured section of the fixing bolt also confirmed the fatigue failure. We propose a method to prevent failure of the fixing bolt of the MEWP from four different standpoints: the manufacturer, safety certification authority, safety inspection agency, and owner.

• Analytical Science and Technology
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• v.18 no.5
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• pp.376-380
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• 2005

Quantitative analysis of silver from the thermal decomposition of chlorinated polymer contained nano silver is described. The chlorine contained in the chlorinated polymer (e.g. PVC) is liberated as hydrochloric acid gas by heating and a lot of silver produces AgCl. $HNO_3$ and $NH_4OH$ were used for dissolving the Ag and the AgCl. The silver complex was formed by $NH_4OH$. Then the complex was decomposed to silver by heating at $500^{\circ}C$ and the Ag was dissolved by dilute $HNO_3$. Recovery of silver in PVC material was 99.0%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.492-494
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• 2004

The purpose of this study is to investigate the hydrochemical characteristics of groundwater in the Umsung area, and to elucidate the effect of host rock type, well depth and mineralization zone on the groundwater chemistry, We carried out chemical analysis, isotopic analysis, statistical analysis of Box-Whisker and trigging analysis for this study. The chemical and isotopic compositions of the groundwater is distinguished into two areas according to host rocks(Cretaceous sedimentary rocks and Jurassic granite) and recharge altitude, and is not greatly influenced by mineralization zone of the mines.

• Journal of the Korean Institute of Gas
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• v.3 no.2 s.7
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• pp.34-42
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• 1999

The discrete variables such as time and sequence must be considered for automating HAZOP analysis of batch processes in contrast with continuous processes. Because these variables can not be explained by the method used in the HAZOP analysis of continuous processes, we have developed the methodology for HAZOP analysis of batch processes on the basis of the relation between discrete variables and continuous ones. In this study, we have discussed the performance of the methodology on a Latex batch process to evaluate its effectiveness.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.632-633
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• 2005

• Bulletin of the Korean Chemical Society
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• v.16 no.1
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• pp.62-65
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• 1995

New compounds of melaminium 2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-4-methoxy-sulfate have been synthesized and characterized by means of chemical analysis, 1H, 13C, and 31P NMR, and IR spectroscopies. When the compounds are subjected to an open flame, they foam without melting to produce a light char with about 50 times volume of the initial compounds. The evaluation of these flame-retardants proves to be efficient for polypropylene. Thermogravimetric analysis discloses that the compounds are also thermally stable for compounding into polypropylene without decomposition.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.304-309
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• 1991

Target transformation factor analysis is applied to analyze the components of unresolved fraction in the elution curve of La, Pr and Gd which is obtained using the chelate agent- impregnated resin and 0.7 M hydrochloric acid as an eluent. We determined the number of components contributing to the unresolved fractions and verified the presence of suspected components.

• Journal of computational fluids engineering
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• v.5 no.2
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• pp.47-54
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• 2000

A robust Navier-Stokes code has been developed to efficiently predict hypersonic flows in chemical nonequilibrium. The HLLE+ flux discretization scheme is used to improve accuracy and robustness of hypersonic flow analysis. An efficient LU approximate factorization method is also used to solve the flow equations and species continuity equations in fully coupled fashion to implicitly treat stiff source terms of chemical reactions. The HLLE+ scheme shows lower grid dependency for the wall heating rates than other schemes. The developed code has been used to compute chemical nonequilibrium air flow through expanding hypersonic nozzle and past two and three dimensional blunt-nosed bodies. The results are in good agreement with existing numerical and experimental results.