• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.967-977
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• 2021

A total of 37 bacterial isolates were obtained from dye-contaminated soil samples at a textile processing factory in Nakhon Ratchasima Province, Thailand, and the potential of the isolates to decolorize and biotransform azo dye Reactive Red 141 (RR141) was investigated. The most potent bacterium was identified as Paenibacillus terrigena KKW2-005, which showed the ability to decolorize 96.45% of RR141 (50 mg/l) within 20 h under static conditions at pH 8.0 and a broad temperature range of 30-40℃. The biotransformation products were analyzed by using UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy. Gas chromatography-mass spectroscopy analysis revealed four metabolites generated from the reductive biodegradation, namely sodium 3-diazenylnaphthalene-1,5-disulfonate (I), sodium naphthalene-2-sufonate (II), 4-chloro-1,3,5-triazin-2-amine (III) and N¹-(1,3,5-triazin-2-yl) benzene-1,4-diamine (IV). Decolorization intermediates reduced phytotoxicity as compared with the untreated dye. However, they had phytotoxicity when compared with control, probably due to naphthalene and triazine derivatives. Moreover, genotoxicity testing by high annealing temperature-random amplified polymorphic DNA technique exhibited different DNA polymorphism bands in seedlings exposed to the metabolites. They compared to the bands found in seedlings subjected to the untreated dye or distilled water. The data from this study provide evidence that the biodegradation of Reactive Red 141 by P. terrigena KKW2-005 was genotoxic to the DNA seedlings.

• 터널과지하공간
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• 제32권6호
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• pp.411-434
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• 2022

사용후핵연료의 심층처분 개념에서 근계영역 암반은 열-수리-역학적 복합거동을 하게 되는 것으로 잘 알려져있다. 이러한 복합거동 과정에서 암석의 여러 물성들은 변화하는데, 이러한 물성변화를 합리적으로 반영하는 경우 고준위방사성폐기물 처분장의 장기안정성의 평가를 위해 활용되는 해석 및 현장시험의 신뢰도를 향상시킬 수 있다. 이를 위해 본 기술보고에서는 암석의 열-수리-역학적 간접복합거동에 관한 국내외 연구사례를 조사하고 분석하였다. 특히, 간접복합거동의 대표적인 사례 중 지하수에 의한 포화 및 온도 증가에 따른 암석의 여러 물성 변화, 응력 변화에 의한 투수계수 변화를 중점적으로 조사·요약하였다.

• 대한본초학회지
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• 제34권2호
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• pp.59-66
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• 2019

Objectives : Decrease in muscle mass and loss of muscle function due to aging are associated with various diseases. As interest in healthy aging increases, efforts to prevent and treat muscle hypoxia as an illness are increasing. Considering the physical limitations, a pharmacologic approach to the treatment of myopenia is needed. Methods : Terminalia chebula Rets has a wide range of pharmacological effects and is used as a medicinal product in traditional medicine. However, the drug effect on the treatment of muscle disorders has not been revealed. The purpose of this study was to evaluate the value of water extract of Terminalia chebula (WETC) as a therapeutic agent to relieve symptoms of muscle hypoxia. Results : WETC showed strong radical scavenging ability. In addition, WETC increased cell activity of myoblast, and we observed that WETC induces myoblast differentiation by immunoblot analysis using differentiation protein markers as well as cell morphology of myoblast. Based on these results, we examined the effect of chebulic acid, chebulagic acid, gallic acid, geraniin, and punicalagin on cell activity and differentiation of myoblasts. Gallic acid significantly increased cell activity of myoblast, and it was found to be an effective substance which not only induces myoblast differentiation but also promotes proliferation. Conclusions : We suggest that the WETC with antioxidant effect and its indicator gallic acid on cell activity, proliferation and differentiation of myoblast can be studied and developed as a food and medicine for prevention and treatment of various muscle diseases.

• 한국수소및신에너지학회논문집
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• 제33권4호
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• pp.391-399
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• 2022

Hydrogen is one of the energy carriers and has high energy efficiency relative to mass. It is an eco-friendly fuel that makes only water (H₂O) as a by-product after use. In order to use hydrogen conveniently and safely, development of production, storage and transfer technologies is required and attempts are being made to apply hydrogen as an energy source in various fields through the development of the technology. For transporting and storing hydrogen include high-pressure hydrogen gas storage, a type of storage technologies consist of cryogenic hydrogen liquid storage, hydrogen storage alloy, chemical storage by adsorbents and high-pressure hydrogen storage containers have been developed in a total of four stages. The biggest issue in charging high-pressure hydrogen gas which is a combustible gas is safety and the backfire prevention device is that prevents external flames from entering the tank and prevents explosion and is essential to use hydrogen safely. This study conducted a numerical analysis to analyze the performance of suppressing flame propagation of 2, 3 inch flame arrestor. As a result, it is determined that, where the flame arrestor is attached, the temperature would be lowered below the temperature of spontaneous combustion of hydrogen to suppress flame propagation.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4134-4145
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• 2022

The collimator is one of the high-heat-flux components used to avoid a series of vacuum and thermal problems. In this paper, the heat load distribution throughout the collimator is first calculated through experimental data, and a transient thermodynamic simulation analysis of the original model is carried out. The error of the pipe outlet temperature between the simulated and experimental values is 1.632%, indicating that the simulation result is reliable. Second, the model is optimized to improve the heat transfer performance of the collimator, including the contact mode between the pipe and the flange, the pipe material and the addition of a twisted tape in the pipe. It is concluded that the convective heat transfer coefficient of the optimized model is increased by 15.381% and the maximum wall temperature is reduced by 16.415%; thus, the heat transfer capacity of the optimized model is effectively improved. Third, to adapt the long-pulse steady-state operation of the experimental advanced superconducting Tokamak (EAST) in the future, steady-state simulations of the original and optimized collimators are carried out. The results show that the maximum temperature of the optimized model is reduced by 37.864% compared with that of the original model. The optimized model was changed as little as possible to obtain a better heat exchange structure on the premise of ensuring the consumption of the same mass flow rate of water so that the collimator can adapt to operational environments with higher heat fluxes and long pulses in the future. These research methods also provide a reference for the future design of components under high-energy and long-pulse operational conditions.

• 한국가스학회지
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• 제27권1호
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• pp.78-85
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• 2023

구리가 함침된 하이드로탈사이트 촉매의 고유 키네틱 데이터를 이용하여 메탄올 수증기 개질 반응의 고정층 반응기 Computational Fluid Dynamics(CFD) 시뮬레이션을 수행하였다. 이전 연구결과로부터 얻어진 20wt%의 구리가 함침된 하이드로탈사이트 촉매의 활성화 에너지는 97.4 kJ/mol, 전 지수 인자는 5.904 × 10¹⁰를 이용하였다. 그리고 고유의 키네틱 데이터를 사용하여 반응온도 (200-450 ℃) 및 메탄올과 물의 몰비 변화에 따른 전환율을 관찰하였다. 또한 위의 키네틱 상수를 power law 모델을 사용하여 Axial 2D Symmetry 시뮬레이션을 통해 상용반응기(I.D. 0.05 - 0.1 m, Length 1 m)의 열 및 물질유동해석을 예측하였다.

• Animal Bioscience
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• 제37권4호
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• pp.697-708
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• 2024

Objective: The objective of this study was to investigate the influence of dietary supplementation of Eucommia ulmoides leaf extract (ELE) on muscle metabolism and meat quality of pigs with and without pre-slaughter transportation. Methods: In a 43-day feeding experiment, a total of 160 pigs with an initial body weight 60.00±2.00 kg were randomly assigned into four groups in a completely randomized design with 10 replicates. Pigs in groups A and C were fed a basal diet and pigs in groups B and D were fed a basal diet supplemented with 0.5% ELE. Pigs were slaughtered with (group B and D) or without (group A and C) pre-slaughter transport. Muscle chemical composition, postmortem glycolysis, meat quality and muscle metabolome were analyzed. Results: Dietary ELE supplementation had no effect on the proximate composition of porcine muscle, but increased free phenylalanine, proline, citruline, norvaline, and the total free amino acids in muscle. In addition, dietary ELE increased decanoic acid and eicosapentaenoic acid, but decreased heptadecanoic acid, oleic acid, trans-oleic acid, and monounsaturated fatty acids in muscle. Meat quality measurement demonstrated that ELE improved meat water holding capacity and eliminated the negative effects of pre-slaughter transport on meat cooking yield and tenderness. Dietary ELE reduced muscle glycolytic potential, inhibited glycolysis and muscle pH decline in the postmortem conversion of muscle to meat and increased the activity of citrate synthase in muscle. Metabolomics analysis by liquid chromatographic tandem mass spectrometric showed that ELE enhanced muscle energy level, regulated AMP-activated protein kinase (AMPK) signaling, modulated glycogenolysis/glycolysis, and altered the metabolism of carbohydrate, fatty acids, ketone bodies, amino acids, purine, and pyrimidine. Conclusion: Dietary ELE improved meat quality and alleviated the negative effect of pre-slaughter transport on meat quality by enhancing muscle oxidative metabolism capacity and inhibiting glycolysis in postmortem muscle, which is probably involved its regulation of AMPK.

• Nuclear Engineering and Technology
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• 제56권10호
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• pp.4068-4076
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• 2024

In the event of severe accidents in pressurized water reactor (PWR) nuclear power plants, the potential leakage of radioactive aerosols through containment cracks poses a considerable radioactive hazard to the public. Understanding aerosol transport and retention in cracks helps reduce the conservatism and uncertainty of radioactive hazard assessment. Concrete cracks are recognized as a pivotal pathway for the leakage of radioactive aerosols, and several researchers have undertaken experimental investigations concerning the aerosol transport and retention in concrete cracks. However, the majority of these studies have rather low gas flow Reynolds numbers. In this work, an experimental setup is built to study aerosol transport and retention in concrete cracks under high Reynolds number flow. The TiO₂ aerosol with a mass median diameter of 1 ㎛ and two concrete crack specimens are used in experiments. The results of gas flow experiments indicate that the Reynolds number is capable of reaching 10547. Combining the flow experimental data and Suzuki's formula, the equivalent heights of these two crack specimens are approximated as 303.67 ㎛ and 231.48 ㎛. The experimental results indicate a notably high retention rate of aerosols, exceeding 0.8. Furthermore, under high Reynolds number flow, the retention rate varies over a relatively narrow range, with the larger the equivalent height of the crack resulting in a lower retention rate. The experimental results match well with the mechanistic analysis based on inertial deposition theory, demonstrating the rationality of the inertial deposition theory.

• 대한조선학회논문집
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• 제61권5호
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• pp.289-296
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• 2024

Recently, with the acceleration of global warming, the importance of carbon neutrality is being emphonasized. In response to this, various technologies are being developed to achieve carbon neutrality, with Carbon Capture, Utilization, and Storage (CCUS) being a prominent example. Research has been conducted on the injection technology to environmentally discharge carbon captured by using one of the carbon capture technologies, HAK-CRS. In this study, numerical simulations were performed using commercial software, ANSYS Fluent, to understand the dispersed multiphase flow between a water jet and CaCO₃ particles. The analysis focused on the differences in particle behavior when injecting CaCO₃ with different flow rates. It was observed that as the mass flow rate of CaCO₃ increased, there was a tendency for the particles to deviate from the flow of the jet and rapidly fall, influenced significantly by gravity. These results indicate that, for CaCO₃ particles to disperse widely, the flow rate should not be excessively high. Given the potential adverse impacts on marine ecosystems due to the high density of CaCO₃, research on injection technology should also be conducted.

• 한국지반공학회논문집
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• 제32권7호
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• pp.25-34
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• 2016

현재 우리나라에서는 해저케이블 또는 해상구조물 기초부, 흙댐, 도로공사 등의 성토재료로 이용된 다짐풍화토에서 침식(Erosion)으로 인한 사면의 불안정성, 오래된 상 하수관이 누수되거나 파열되어 발생하는 도심지 싱크홀 등의 문제가 발생하고 있다. 이와 같이 건설재료로 많이 이용된 풍화토는 지하수 및 지표수 흐름이 발생할 때 다양한 입자 크기의 점토, 실트 및 세립의 모래들과 함께 침식되거나 세굴 되어 소규모 공동을 형성하며, 일단 침식이나 세굴이 발생되기 시작하면 점차 침식율이 증가하게 되어 급격한 파괴에 도달한다. 본 연구에서는 회전식 수리저항성능 실험기(RCT)를 이용하여 다양한 상대밀도와 선행압밀압력으로 압밀된 다짐화강풍화토의 수리저항성능을 평가하였다. 또한 회전으로 인하여 일정하게 세굴되지 않은 시료의 단면해석을 위해 영상처리기법을 도입하였다. 연구결과 침식으로 인하여 시료의 형상이 일정하지 않는 경우, 계산된 임계전단응력에 큰 오차가 발생되는 것으로 확인되었으며 제안된 영상처리기법으로 보정된 반지름을 이용할 경우보다 정확한 한계 및 임계전단응력 계산이 가능한 것으로 나타났다. 또한 상대밀도와 선행압밀압력이 증가할수록 한계전단응력은 증가하나 임계전단응력은 선행압밀하중 증가에 의한 효과는 크지 않은 것으로 나타났으며, 선행압밀압력에 의한 응력이력보다는 초기 상대밀도의 효과가 더 큰 것으로 나타났다.