• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.4
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• pp.528-534
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• 2024

In continuous research of detecting highly toxic chemical warfare agents to ensure preparedness for the future battlefield, flexible and wearable sensor platforms with high sensitivity are still demanding. Herein we demonstrate a facile fabrication of polypyrrole-based chemiresistors on cellulose paper for the detection of nerve gas simulants. In order to optimize electrical properties of sensor platform, conducting polymer made of polypyrrole were first synthesized on flexible cellulose paper and interdigitated electrodes were formed thereon. Following confirmation of polypyrrole and/or oxime moiety through FT-IR analyses, electrical characteristics were measured in the various ratio of monomers between simple pyrrole and oxime-modified one. Typically for the optimized chemiresistor(2:8 molar ratio of simple pyrrole and oxime-modified one), eleven species of chemical warfare agents were examined and enhanced conductivity(10⁴~10⁵ order) was observed for three simulants(diethyl cyanophosphonate, diisopropyl fluorophosphonate and diethyl chlorophosphonate), which was mainly attributed to intermolecular hydrogen bonding, while no significant responses was recorded against sixteen common volatile organic chemicals.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.718-725
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• 2017

A liquid storage tank is one of the most important structures in industrial complexes dealing with chemicals, and its structural damage due to an earthquake may cause a disastrous event such as the leakage of hazardous materials, fire, and explosion. It is thus essential to assess the seismic fragility of liquid storage tanks and prepare for seismic events in advance. When a liquid storage tank is oscillated by a seismic load, the hydrodynamic pressure caused by the liquid-structure interaction increases the stress and causes structural damage to the tank. Meanwhile, the seismic fragility of the structure can be estimated by considering the various sources of uncertainty and calculating the failure probabilities in a given limiting state. To accurately evaluate the seismic fragility of liquid storage tanks, a sophisticated finite element analysis is required during their reliability analysis. Therefore, in this study, FERUM-ABAQUS, a recently-developed computational platform integrated with commercial finite element and reliability analysis software packages, is introduced to perform the finite element reliability analysis and calculate the failure probability of a liquid storage tank subjected to a seismic load. FERUM-ABAUS allows for automatic data exchange between these two software packages and for the efficient seismic fragility assessment of a structure. Using this computational platform, the seismic fragility curve of a liquid storage tank is successfully obtained.

• Korea Trade Review
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• v.45 no.2
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• pp.51-65
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• 2020

According to an analysis of 560 foreign-invested companies investing in South Korea's manufacturing industry, the following three facts were found. First, the proportion of sales by manufacturing foreign-invested companies is divided into 68.5 percent of domestic sales and 31.5 percent of exports. From 68.5 percent of domestic sales, sales to Korean companies are 60.5 percent, including 37.1 percent for large companies and 23.4 percent for small and medium-sized companies, while only 8.0 percent for domestic consumers. Second, the investment sectors of manufacturing foreign-invested enterprises are 'machine and equipment manufacturing', 'chemical and chemical-chemical material manufacturing-excluding pharmaceuticals', 'electronic components, computers, video, sound and communication equipment manufacturing' and 'vehicle and trailer manufacturing'. It overlaps with electric·electronics, petro-chemicals and automobiles, which are Korea's main industries and areas of Korean global companies. Third, 31.5 percent of the sales of foreign-invested companies in the manufacturing sector are exported. Foreign-invested companies export their products to use them for their parents or affiliates or to the third countries. The analysis shows that foreign-invested companies invested in Korea for B2B transactions with Korean companies. The implications are that Korea can attract foreign investments by utilizing Korean companies' demand for intermediate goods. Foreign-invested companies can invest in Korea in order to use Korea, which has signed free trade agreements with the US, the EU and ASEAN, as an export platform.

• Journal of Environmental Health Sciences
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• v.50 no.4
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• pp.237-256
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• 2024

Background: Human health and environment exposure assessments of chemicals are essential part for REACH and BPR as well as K-REACH and K-BPR. Several useful exposure assessment tools have been developed and updated to become extensively used during more than fifteen years of chemical registrations under REACH and their updates are still going on. Objectives: Evolution of regulatory tools for environment, workers and consumers exposure assessments under REACH is investigated focusing on why and how tools have been developed and updated for the future regulatory tools in Korea. Methods: REACH regulatory tools including EUSES, ECETOC TRA and CHESAR as well as built-in models SimpleTreat and SimpleBox were chosen with other frequently used Tier 1 and 2 tools. Available resources such as homepage information, background documents, related scientific reports, relevant journal publications, up-to-date lists of new version publications, release notes and user guides were reviewed extensively and summarized using easy-readable Tables and Figures. Results: SimpleTreat and SimpleBox are built-in models both for EUSES and ECETOC TRA (Environment). ECHA's CHESAR contains ECETOC TRA (Workers) and ECETOC TRA (Consumers) as well as EUSES and ECETOC TRA (Environment) for environment exposure assessment while results of Tier 2 Stoffenmanager and ConsExpoWeb can be imported. Evolution of CHESAR from version 1 (2010) to 3.8 (2023) has focused on the compatibility of frequent updates of IUCLID, importing functionality, editability, updated use maps, harmonised conditions of use as well as updates of the built-in tools evolved according to scientific development, refinements of the tool, increased conservatism and user-friendliness. CHESAR Platform 1.0 will soon be published to serve both for REACH and BPR. Conclusions: Updates of the tools can be successfully continued by transparency of the tools, participation of industry sectors for tool refinements and tool developers'/authorities' encouragements of partners/users to jointly innovate tools through scientific researches, tool validations and user feedback.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.193-201
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• 2022

5-HMF(5-Hydroxymethylfurfural) and LA(levulinic acid) derived from biomass are green platform chemicals, which have a wide of potential applications as biofules and biochemicals. In this study, the kinetics of LA formation from glucose decomposition with various concentration of sulfuric acid at different temperature was investigated. The experiments were performed in a broad temperature (140-200 ℃), using H₂SO₄ (1-3 wt%) as the catalyst. Glucose solution was made by dissolving 1 g of glucose in 10 ml of H₂SO₄ solution. The reactions rates increased with temperature and the activation energy showed a similar tendency to previous reported values. Reaction time for maximum concentration of 5-HMF decreased as the temperature increased. Furthermore, the decomposition of 5-HMF was fast as the acid concentration increased. Reaction time to reach maximum concentration of levulinic acid was reduced as the acid concentration increased. Continuing to raise the temperature decreased the maximum concentration of levulinic acid and increased the amount of humins. On the basis of results, kinetic parameters help to understand mechanism of LA and 5-HMF. In addition, this study provides useful information to achieve high concentration of LA and 5-HMF from biomass.