• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.203-218
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• 2009

The development of lithium-ion battery (LIB) technologies and their application in the field of large-scale power sources, such as electric vehicles (EVs), hybrid EVs, and plug-in EVs require enhanced reliability and superior safety. The main components of LIBs should withstand to the inevitable heating of batteries during high current flow. Carbonate solvents that contribute to the dissociation of lithium salts are volatile and potentially combustible and can lead to the thermal runaway of batteries at any abuse conditions. Recently, an interest in nonflammable materials is greatly growing as a means for improving battery safety. In this review paper, novel approaches are described for designing highly safe electrolytes in detail. Non-flammability of liquid electrolytes and battery safety can be achieved by replacing flammable organic solvents with thermally resistive materials such as flame-retardants, fluorinated organic solvents, and ionic liquids.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.717-722
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• 2011

Currently, melamine is being used variously in our lives such as resins, flame retardants, adhesive, laminate etc. And understandably sewer of stream of wastewater containing Melamine has also increased. GHS (Globally Harmonized System of Classification and Labelling of Chemicals) of EU safety guidelines says that it can cause cancer. Still, study on toxicity of Melamine is going on. In this research, melamine contamination level of the Han River and River Basin was analyzed by HPLC/UV. And the experiments of GAC adsorption were conducted and the model was studied. We collected the 3 same samples at the suburbs of Paldang Dam located in the relative upstream in Han River and Ttukseom amusement park, the downstream region and collected samples equally at the Hongreung stream, Wangsuk stream, Cheonggye stream among streams flowing into Han River and then measured Melamine concentration after purification. As a result, melamine was not detected at the suburbs of Paldang Dam and it was detected at Ttukseom amusement park, the downstream of it, in the concentration of $0.312{\mu}g/L$. The Wangsuk stream with $0.578{\mu}g/L$ highest Cheonggye stream and Hongreung stream was detected with each $0.197{\mu}g/L$ and $0.325{\mu}g/L$. Although the concentration was low in general, melamine detection could be checked at most point. In 1970, the world capacity of Melamine was estimated at 200,000 ton, with current production estimated to be 1,400,000 ton. Melamine of Han River and rivers flowing into Han River is present at low concentration but pollution will increase in the future due to increase of use. Depending on the size of activated carbon in the experiment were slightly different. But the breakthrough model is almost identical.

• Fire Science and Engineering
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• v.33 no.3
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• pp.9-20
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• 2019

This study was examined fire risk properties of wood specimen for the constructional interiors, especially focusing on the fire performance index (FPI) and the fire growth index (FGI) as heat hazard characteristics. Flame retardants were synthesized using boric acid, boronic acid and tetraethoxyorthosilicate. Heat release characteristics were measured by using a cone calorimeter (ISO 5660-1) and cypress was used. The external heat flux as fire intensity was maintained at 50 kW/㎡. The measured fire performance index (FPI) after burning was increased by 1.6 times for boric acid/silicone (BA/Si) sol, each 1.1 times for isobutylboronic acid/silicone (IBBA/Si) sol and phenylboronic acid/silicone (PBA/Si) sol compared with cypress. Fire risk by the fire performance index was increased BA/Si, IBBA/Si ≈ PBA/Si order. The fire growth index was decreased 94% for the BA/Si and 8% for the IBBA/Si sol, and was increased by 17% for the PBA/Si sol. Fire risk by the fire growth index was increased BA/Si, IBBA/Si, PBA/Si order. Overall fire risk was higher in the order of BA/Si < IBBA/Si < PBA/Si.

• Fire Science and Engineering
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• v.30 no.4
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• pp.65-72
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• 2016

This study examined the generation of combustion toxic gases of pinus rigida specimens processed with bis-(dimethylaminomethyl) phosphinic acid (DMDAP), bis-(diethylaminomethyl) phosphinic acid (DEDAP), and bis-(dibutylaminomethyl) phosphinic acid (DBDAP). Each pinus rigida plate was coated three times with 15 wt.% flame retardants in an aqueous solution. The specimens were then dried at room temperature. The production of combustion toxic gases was investigated using a cone calorimeter (ISO 5660-1). The first time to peak mass loss rate ($1^{st}-TMLR_{peak}$) processed with the chemical additives decreased to 5.9 from 41.2% compared with the unprocessed specimen. The second time to the peak mass loss rate ($2^{nd}-TMLR_{peak}$) for the processed specimens was decreased 1.8% for DMDAP and 5.3% for DBDAP and increased 1.8% for DEDAP. The peak carbon monoxide ($CO_{peak}$) production was 1.5 to 2.0 times higher than that of the unprocessed plate. The peak carbon dioxide ($CO_{2peak}$) production was reduced 0.01 times for DMDAP and increased 1.15 to 1.19 times for DEDAP and DBDAP compared with the unprocessed specimens. In particular, the oxygen concentration was much higher than 15%, which can be fatal to humans and the resulting hazard can be eliminated. Overall, the combustion toxicity of flammable gas were increased partially by the chemical additives compared with those of the unprocessed plate.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.124-130
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• 2013

Of all the brominated flame retardants (BFRs), TBBPA has the largest production volume (50% of the BFRs in current use). It is interest to investigate how they may degrade, because of it can pose an environmental hazard. By using UV-A (${\lambda}=352nm$ ), we have found that the UV-A irradiation increased the photodecomposition reaction rate of TBBPA in an intensity-dependent manner. We also observed 2,6-dibromo-p-benzosemiquinone radical ($a_{2H}=2.36G$, g = 2.0056) generated from TBBPA by reaction with singlet oxygen ($^1O_2$). On the other hand, when an aqueous preparation of HA was irradiated in the presence of TBBPA, the typical spectrum of semiquinone radical was detected by electron spin resonance (ESR). And then, we have found that the photodecomposition rate of TBBPA is decreased in depend on HA concentration. Radical formation and the reactive rate of TBBPA were inhibited by sodium azide used as a singlet oxygen quencher. Therefore we report that a similar $^1O_2$-induced oxidation can be initiate in aqueous solutions of TBBPA dissolved in humic acid (HA) by the UV-A irradiation (${\lambda}=352nm$). From these results, we suggest that the reaction rate of HA with $^1O_2$ is faster than that of TBBPA with $^1O_2$.

• Fire Science and Engineering
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• v.33 no.2
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• pp.9-19
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• 2019

Experiments on the combustion characteristics of untreated wood specimens and those treated with four types of silicone compounds were carried out using a cone calorimeter according to the ISO 5660-1 standard. 3-Aminopropyltrimethoxysilane (APTMS), 3-(2-aminoethylamino) propylmethyldimethoxysilane (AEAPMDMS), and 3-(2-aminoethylamino) propyltrimethoxysilane (AEAPTMS) were used as the silane compounds. The flame retardants were synthesized with sodium silicate and amino silane compounds. The measured time to ignition after combustion at an external heat flux of $50kW/m^2$ was 9 s to 11 s. Time to ignition was marked with a delayed value in the 3 s to 5 s range. The peak heat release rate ($HRR_{peak}$) was reduced by 5 to 20% compared with the uncoated specimen, and AEAPMDMS showed the highest initial fire risk. The total heat release (THR) was decreased by 1 to 22%. Compared to the untreated specimen, the fire performance index (FPI) of the specimens coated with silicone sol compounds increased by 1.5 to 2.2 fold. The fire growth index (FGI) of the AEAPMDMS specimen was increased by 30% and the others were decreased by 93 to 94%. Therefore, the fire risk of wood coated with silicone compounds was improved in terms of the heat risk properties.

• Journal of Life Science
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• v.32 no.1
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• pp.70-77
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• 2022

Endocrine disrupting chemicals (EDCs) have been attracting significant attention in modern society, owing to the increased incidence rate of various diseases along with population growth. EDCs are found in many commercial products, including some plastic bottles and containers, detergents, liners of metal food cans, flame retardants, food, toys, cosmetics, and pesticides. EDCs have a hormonal effect on the human body, which disrupts the endocrine system, notably affecting sexual differentiation and normal reproduction, and can trigger cancer as well. Recently, the association between neurological diseases and EDCs has become a hot topic of research in the field of neuroscience. Considering that EDCs negatively affect not only neuronal proliferation and neurotransmission but also the formation of the neuronal networks, EDCs may induce neurodevelopmental disorders, such as autism spectrum disorders and attention-deficit/hyperactivity disorder as well as neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. In light of these potentially deleterious outcomes, important efforts have been underway to minimize the exposure to EDCs through appropriate regulations and policies around the world, but chemicals that have not yet been associated with endocrine disrupting properties are still in wide use. Therefore, more epidemiological investigations and research are needed to fully understand the effects of EDCs on the nervous system.

• Analytical Science and Technology
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• v.19 no.3
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• pp.244-254
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• 2006

Flame retardants are added to prevent catching fire and to slow down the burning process. PBDEs are known to affect thyroid hormones and hormone disruption. The aim of this study was to propose a manual for determination of PBDEs, and investigate the accumulation of PBDEs(BDE-28, 47, 99, 100, 153, 154 and 183) in fish&shellfish and human milk samples. Pre-treatment for PBDEs determination, alkali digestion and L-L(Liquid-Liquid) extraction method could be applied to fish and shellfish. When Multi-layer column was used for cleaning up the sample, 50 mL of hexane and 100 mL of hexane:dichloromethane(9:1) solutions were used for pre- and post-elution, respectively. Activated-carbon column was optimized by a 100 mL of hexane:dichloromethane(3:1). The result of fish, highest concentration was detected in flatfish, 890 pg/g(wet weight). The other side, lowest concentration was detected in pollack, 40 pg/g(wet weight). The result of breast milk, PBDEs was detected 2,580 and 3,600 pg/g(lipid weight) from breast milk of Seoul and Juju, respectively. BDE-153 and 183 were not detected in all samples. There was no difference in PBDEs level was not difference between first and second delivery. In this study, we could find that PBDEs level in Korea is lower than other countries.

• Korean Journal of Environmental Agriculture
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• v.35 no.4
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• pp.270-277
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• 2016

BACKGROUND: Significant amount of bisphenol A has been released from the manufacturing process of plastics, epoxy resins, dental material and flame retardants. Bisphenol A has been detected at trace levels in wastewater, surface water, landfill leachate and drinking water. However, the residual survey of bisphenol A has not been performed in agricultural reservoir beside agricultural environment cultivating crops. This study was conducted to monitor the residual bisphenol A in national agricultural reservoirs and understand a level of contamination of bisphenol A in the agricultural environment in Korea. METHODS AND RESULTS: The water and water sediment were collected at agricultural reservoirs in Chungnam, Chungbuk, Kyunggi, Jeonnam, Jeonbuk, Kyungnam and Kyungbuk province. Bisphenol A was analyzed by the LC-MS/MS with triple quad 4500. The recovery of water and water sediment in the agricultural reservoirs showed the level of 95.7~97.2% and 91.5~100.3%, respectively. CONCLUSION: Bisphenol A was detected at the level of $0.05{\mu}g/L{\sim}0.18{\mu}g/L$ and $0.1{\mu}g/kg{\sim}34{\mu}g/kg$ in water and water sediment of the reservoirs, respectively. Based on the results, the residue of bisphenol A will be tried in the crops surrounding these agricultural reservoirs where bisphenol A detected above $10{\mu}g/kg$ of bisphenol A.

• Journal of Korean Society of Forest Science
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• v.56 no.1
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• pp.1-25
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• 1982

Plywood used for construction as a decorative inner material is inflammable and can cause fire accidents. causing destruction of human life and property. To diminish the fire disaster, fire retardant plywood is indeed required. In the methods of manufacturing the fire retardant plywood, a soaking method is occasionally used. However after soaking plywood into fire retardant chemical solutions redrying of soaked plywood is of the utmost importance. In this study 3.5mm and 5.0mm thickness plywoods were selected for fire retardant treatment. Treating solutions were prepared for 20% dilute solutions of ammonium sulfate, monoammonium phosphate, diammonium phosphate, borax-boric acid minalith, and water solution, 1-, 3-, 6-, and 9 hour-soaking treatments in borax-boric acid and minalith, and 6- and 9 hours in the other chemicals were applied and after the treatment hot drying was applied to treated plywoods at $90^{\circ}C$, $120^{\circ}C$ and $150^{\circ}C$ of press temperature. Drying rates, drying curves, water absorption rates of fire retardant chemicals, weight per volume and fire retardant degree of plywood were investigated. The results may be summarized as follows: 1) In the 9 hours-soaking treatment of fire retardants by hot and cold bath method, the chemical retentions of 3.5mm thickness plywood could be attained within the range ($1.125-2.25kg/(30cm)^3$) of minimum retention specification as follows: $1.353kg/(30cm)^3$ in monoammonium phosphate, $1.331kg/(30cm)^3$ in diammonium phosphate, $1.263kg/(30cm)^3$ in ammonium sulfate, $1.226kg/(30cm)^3$ in borax-boric acid. But the chemical retention, $0.906kg/(30cm)^3$, in minalith could not be attained within the range of minimum retention specification. And also in case of 5.0mm thickness plywood, chemical retentions, as $1.356kg/(30cm)^3$ and $1.166kg/(30cm)^3$ respectively, of ammonium sulfate and diammonium phosphate could be attained within the range minimum retention specification, but the other fire retardant chemicals could not. 2) In the 6- and - hours-soaking treatments of 3.5mm and 5.0mm thickness plywood, the drying curve sloped of chemical treated plywood was smaller than that of water treated. The drying rate related to thickness of treated plywood, was about three times as fast in 3.5mm thickness plywood compared with 5.0mm thickness plywood. 3) In the treatment at $120^{\circ}C$ of hot platen temperature, the drying rates of chemical-treated plywood showed the highest quantity in diammonium phosphate of 3.5mm and 5.0mm thickness plywood. But the drying rate of water treated plywood was highest during the 6- and 9 hours-soaking treatments. 4) The drying rate remarkably increased with proportion to increase of the platen temperature, and the values were respectively 1.23%/min., 6.54%/min., 25.75%/min. in hot platen temperature of $90^{\circ}C$, $120^{\circ}C$, $150^{\circ}C$ in 3.5mm thickness plywood and 0.55%.min., 2.49%/min., 8.19%/min. in hot platen temperature of $90^{\circ}C$, $120^{\circ}C$, $150^{\circ}C$ in 5.0mm thickness plywood. 5) In the fire retardant degree of chemical treated plywood, the loss in weight was the smallest in diammonium phosphate, next was in monoammonium phosphate and ammonium sulfate, and the greatest was in borax-boric acid and minalith. And the fire-retardant effect in burning time, flame-exhausted time and carbonized area were greatest in diammouniun phosphate, next were in monoammonium phosphate and ammonium sulfate, and the weakest were in borax-boric acid and minalith.