• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.112-117
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• 2017

This study demonstrated the emission of combustion gases of medium density fibreboard (MDF)s coated with piperazinomethyl-bis-phosphonic acid (PIPEABP), methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP), N,N-dimethylethylenediaminomethyl-bis-phosphonic acid (MDEDAP), or bis-(dimethylaminomethyl) phosphinic acid (DMDAP). Each MDFs were coated in three times with a brush with 15 wt% aqueous solution of the phosphorus-nitrogen acid additives. After the specimens were dried at room temperature, the emission of combustion gases was tested using a cone calorimeter (ISO 5660-1, 2). The peak smoke production rate ($SPR_{peak}$) of the specimens coated with phosphorus-nitrogen acids was 18.5 to 41.5%, which is lower than that of using the virgin plate. However, the production of peak carbon monoxide ($CO_{peak}$) was 6.7 to 24.2% higher than that of using the virgin plate. Also, the peak carbon dioxide ($CO_{2peak}$) was 4.2 to 24.4% lower than that of using virgin plate. While the peak oxygen depletion rate was much higher than the level of 15%, which can be fatal to humans and the resulting risk could thus be eliminated. Overall, the combustibility of coated specimens was partially suppressed, but showed a negative effect on the reduction of carbon monoxide.

• Journal of the Korea Institute of Building Construction
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• v.11 no.4
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• pp.326-332
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• 2011

Carbon, Aramid, Boron and Glass fibers are used as fibrous materials to promote structural bearing strength. Of these fiber types, carbon fiber is the most commonly used material, and is characterized by having a one-way direction, which is strengthened by tensile strength due to the attached direction only, while other types of fibers are two-way. Therefore, when applied in the field, the attachment direction of fiber is a very important factor. However, when fiber direction is not mentioned in the design drawing, there sometimes is no improvement in structural strength, as the fiber is being installed by a site engineer or workers who lack structural knowledge. The purpose of this study was to propose an optimal direction of carbon fiber through a comparison & analysis of reinforcing efficiency with reinforced experimental columns that used carbon fibers in each of the inclined, horizontal and vertical directions. According to the results, horizontal direction in the reinforced column was improved by 153.43%, but vertical direction was 104.61% only, and it was understood this was due to increased tensile strength along the fiber direction. For this reason, it is necessary to include information regarding fiber direction in design and site management.

• Food Science and Preservation
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• v.22 no.6
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• pp.886-892
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• 2015

The antimicrobial effects of ten isothiocyanates (ITCs) present in cruciferous vegetables and radish root hydrolysate were investigated against pathogenic bacteria from olive flounder. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured against two gram-positive bacterial strains (Streptococcus parauberis, S. iniae) and four gram-negative bacterial strains (Edwardsiella tarda, Vibrio ichthyoenteri, V. harveyi, Photobacterium damselae) by using a broth microdilution technique. The antibacterial activity of ITCs was in the order sulforaphane > sulforaphene > phenylethyl ITC > erucin > benzyl ITC > iberin > I3C > allyl ITC > phenyl ITC > hexyl ITC. The susceptibility of fish pathogens to ITCs was in the order of V. harveyi > E. tarda > P. damselae > S. parauberis > S. iniae > V. ichthyoenteri. Antimicrobial activity (MIC) of radish root hydrolysate was 0.250 mg/mL against S. iniae, 0.438 mg/mL against S. parauberis, and 0.500 mg/mL against both E. tarda and V. harveyi. The aliphatic ITCs were potent inhibitors of the growth of fish pathogens, followed by aromatic ITCs and indolyl ITC. The presence of a double bond in the chemical structure of ITCs decreased antibacterial activity, while ITCs with a thiol (-S-) group and a longer carbon chain increased antibacterial activity. These results suggest that ITCs have strong antibacterial activities and may be useful in the prevention of fish pathogens.

• Korean Journal of Materials Research
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• v.3 no.2
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• pp.131-139
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• 1993

Abstract Alloying elements such as AI, Ti, Nb and B in the extra low carbon AI-killed steel precipitate as nitrides or carbides and change the recrystallization texture structure of the steel during heattreatment with the result of strong effects on the deep drawability of the steel sheet. In this study the effects of fine precipitates such as nitrides and carbides on the texture of extra low carbon steels into which Ti, Nb, B, P, Si and Mn were added as alloying elements were investigated by means of TEM, SEM and optical microscopic analyses. Fine N$b_2$C and T$i_2$AIN precipitates are mainly observed in the steel containing both Nb and Ti, while fine AIN and coarse BN precipitates are observed in the Nb~containing steel and coarse T${i_4}{N_3}$ and ${N_10}{N_22}$/T$i_68$ precipitates are observed in the Ti-containing steel. The grain size of the Ti containing steel is larger than that of the Nb containing steel and that of the one containing both Nb and Ti.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.349-354
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• 2023

This study wa s conducted a s pa rt of ma ximizing the use of ca rbon dioxide by a pplying CCU(Ca rbon Ca pture, Utiliza tion) a mong technologies for reducing CO₂ in the cement industry. In a carbon dioxide curing environment, changes in carbonation depth and changes in basic physical properties by age due to the mixing of carbonation reaction accelerators were usually targeted at Portland cement paste. In addition, in order to check the fixed amount of CO₂ in the concrete field, a thermal analysis method was applied to evaluate CaCO₃ decarbonization at high temperatures. As a result of the evaluation, it was confirmed that the carbonation depth in the cured body significantly increased due to the incorporation of CRA in the carbonation depth diffusion performance. In addition, it was confirmed that the weight reduction rate increased by 23.8 % and 40.77 %, respectively, compared to Plain, in the order of curing conditions for constant temperature and humidity and curing conditions for carbonation chambers, so it was confirmed that the amount of excellent CaCO₃ produced by the addition of CRA increased as the concentration of CO₂ increased.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.665-674
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• 2015

The final goal of this research is to develop a botanical biofiltration system, which combines green interior, biofiltering, and automatic irrigation, which can purify indoor air pollutants according to indoor space and the size of biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be more suitable for indoor space utilization. This study was performed to compare indoor air quality between the space adjacent to a botanical biofilter and the space away from the biofilter (control) without generation of artificial indoor air pollutants, and to evaluate plant growth depending on multiple floors within the biofilter. Each concentration of indoor air pollutants such as TVOCs, monoxide, and dioxide in the space treated with the biofilter was lower than that of control. Dracaena sanderiana ‘Vitoria’ and Epipremnum aureum ‘N Joy’ also showed normal growth responses regardless of multiple floors within the biofilter. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was effective for indoor air purification.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.559-569
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• 2018

Catalytic supports made of carbon have many advantages, such as high coking resistance, tailorable pore and surface structures, and ease of recycling of waste catalysts. Moreover, they do not require pre-reduction. In this study, ash-free coal (AFC) was obtained by the thermal extraction of carbonaceous components from raw coal and its performance as a carbon catalytic support was compared with that of well-known activated carbon (AC). Nickel was dispersed on the carbon supports and the resulting catalysts were applied to the steam reforming of toluene (SRT), a model compound of biomass tar. Interestingly, nickel catalysts dispersed on AFC, which has a very small surface area (${\sim}0.13m^2/g$), showed higher activity than those dispersed on AC, which has a large surface area ($1,173A/cm^2$). X-ray diffraction (XRD) analysis showed that the particle size of nickel deposited on AFC was smaller than that deposited on AC, with the average values on AFC ${\approx}11nm$ and on AC ${\approx}23nm$. This proved that heteroatomic functional groups in AFC, such as carboxyls, can provide ion-exchange or adsorption sites for the nano-scale dispersion of nickel. In addition, the pore structure, surface morphology, chemical composition, and chemical state of the prepared catalysts were analyzed using Brunauer-Emmett-Taylor (BET) analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and temperature-programmed reduction (TPR).

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.964-970
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• 2023

As part of the International Maritime Organization ef orts to reduce greenhouse gas emissions, the maritime industry is exploring low-carbon fuels such as liquefied natural gas and methanol, as well as zero-carbon fuels such as hydrogen and ammonia, evaluating them as environmentally friendly alternatives. Particularly, ammonia has substantial operational experience as cargo on transport ships, and ammonia ship engines are expected to be available in the second half of 2024, making it relatively accessible for commercial use. However, overcoming the toxicity challenges associated with using ammonia as a fuel is imperative. Detection is possible at levels as low as 5 ppm through olfactory senses, and exposure to concentrations exceeding 300 ppm for more than 30 min can result in irreparable harm. Using the KORA program provided by the Chemical Safety Agency, an assessment of the potential risks arising from leaks during ammonia bunkering was conducted. A 1-min leak could lead to a 5 ppm impact within a radius of approximately 7.5 km, affecting key areas in Busan, a major city. Furthermore, the potentially lethal concentration of 300 ppm could have severe consequences in densely populated areas and schools near the bunkering site. Therefore, given the absence of regulations related to ammonia bunkering, the potential for widespread toxicity from even minor leaks highlights the requirement for the development of legislation. Establishing an integrated system involving local governments, fire departments, and environmental agencies is crucial for addressing the potential impacts and ensuring the safety of ammonia bunkering operations.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.82-82
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• 2022

천마(天麻, Gastrodia elata Blume)는 난초과(蘭草科, Orchidaceae)에 속하는 식물로 잎과 뿌리가 없어 탄소동화능력이 없으며, 뽕나무버섯균과 공생하는 기생식물이다. 주요 함유된 성분은 gastrodin, 4-hydroxylbenzyl alcohol, vanillin, vanillyl alcohol, ergothioneine 등이 있고, 주로 진정(鎭靜), 진경(鎭痙), 통락(通絡)의 효능이 있으며, 두통, 반신불수, 언어장애, 현훈(眩暈), 고혈압 등에 사용되고 있다. 천마는 노지 재배에 따른 안정생산 문제가 지속적으로 발생하고 있다. 혹한, 폭우 등 기상환경에 따른 연차간 수량성 차가 673~1,175kg/10a로 크고, 정식 후 원목·종균·자마의 공생관계 형성이 늦어져 자마 생존율이 70% 이하로 낮으며, 18개월 장기 재배 시 생육 환경이 불량해져 썩음병이 많이 발생하고 있다. 본 연구는 비가림시설, 종균 선(先) 접종 배양목 및 20g 이상의 자마를 사용하여 재배기간을 18개월에서 12개월로 6개월을 단축하고자 수행하였다. 본 실험은 종균 선접종 배양목 생산을 위해 ^①원목의 종균 접종 시기는 4월 하순, 6월 상순, 7월 중순으로 40일 간격으로 처리하였고, 이렇게 생산된 배양목을 활용하여 정식은 이듬해 4월 상순, 수확은 그 이듬해 3월 하순으로 설정하였다. 또한, 종균 선접종 배양목을 활용한 ^②천마의 정식 시기는 3월 상순, 4월 상순, 5월 상순으로 30일 간격으로 처리하였고, 수확 시기는 이듬해 2월 하순, 3월 하순, 4월 하순으로 설정하여 천마의 생육상황 및 생산성을 조사하였다. ^①원목의 종균 접종시기를 검정한 결과, 자마 생존율은 4월 하순과 6월 상순 처리가 무처리에 비해 15%가 높았고, 천마 수량은 무처리 대비 4월 하순과 6월 상순 처리구에서 각각 2.07배, 1.64배 높았다. ^②천마의 정식 시기를 검정한 결과, 천마의 유효적산온도는 2,400℃로 3월 상순 처리구는 2,446℃로 충족하였고, 4월 중순 처리구는 2,375℃로 거의 충족하였으나, 5월 상순 처리구는 2,178℃로 222℃가 부족하였다. 자마 생존율은 3월 상순 처리 시 95%로 가장 높았고, 정식 시기가 늦어질수록 자마 생존율이 낮아지는 경향을 보였으며, 수량성은 5월 상순 처리 대비 3월 상순이 3.56배, 4월 상순이 3.43배 높았다. 따라서, 자마 생존율, 유효적산온도, 천마 수량성 등의 결과에 따라 원목의 적정 종균 접종 시기는 4월 하순과 6월 상순 사이고, 천마의 적정 정식 시기는 3월 상순과 4월 상순 사이며, 비가림시설, 종균 선접종 배양목 및 우량자마를 활용하면 재배기간을 노지 대비 6개월 이상 단축할 수 있을 것으로 판단되었다.

• Journal of the Korea Society of Computer and Information
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• v.29 no.4
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• pp.183-189
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• 2024

Against the backdrop of IMO's stricter environmental regulations due to global warming, Europe's Fit for 55 plan, and other initiatives, the establishment of infrastructure for the supply of environmentally friendly marine fuels and policy analysis are more critical than ever. This study comprehensively analyzes existing research and policies on the supply of environmentally friendly marine fuels, as well as trends in regulations, industry responses, and the current status of infrastructure for the supply of environmentally friendly fuels, to draw insightful conclusions. The results show that the establishment of infrastructure for the supply of environmentally friendly fuels is as important as the introduction of environmentally friendly ships, due to the strengthening of environmental regulations. LNG is a viable option in the short term, but a transition to carbon-free fuels is necessary in the long run. In this regard, a strategic approach is needed to focus support on fuels that are advantageous to produce, considering domestic industrial conditions from a long-term perspective. Therefore, the government should actively promote infrastructure development through measures such as supporting the development and supply of environmentally friendly fuels, improving regulations and providing incentives, attracting private investment, and strengthening international cooperation. This study is expected to serve as a valuable resource for setting policy directions for the transition to an environmentally friendly maritime industry. Future research will include a comparative analysis of the economic viability of environmentally friendly fuels and basic research on the selection of fuels that are advantageous to Korea.