• 공업화학
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• 제27권6호
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• pp.606-611
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• 2016

본 연구에서는 오염된 토양 속에 함유된 중금속과 페놀의 처리에 대하여 직류 전원과 펄스 전원을 적용하여 고찰하였다. 직류 전원을 사용하여 오염된 토양을 처리하였을 때 구리, 아연, 비소, 납의 제거 효율은 각각 70, 87, 12, 11%를 나타내었고, 페놀은 85% 이상이 제거되었다. 그리고 펄스 전원을 사용하였을 때 구리, 아연, 비소, 납의 제거효율이 각각 87, 91, 37, 38%이었으며, 페놀은 88% 제거되었다. 이러한 결과들은 펄스 전원을 오염된 토양에 적용하였을 때, 전기삼투 현상은 낮아졌지만 중금속들의 전류이동 속도가 증가함을 알 수 있었다. 또한 토양의 점토 성분에 의한 흡착 능력의 향상으로 인하여 비소와 납의 제거효율이 증가되었다. 따라서 이러한 직류 전원과 펄스 전원을 이용하는 동전기 실험 결과들은 여러 가지 중금속들과 페놀을 처리하는 복원 기술로 유용하게 활용될 수 있을 것이다.

• Journal of Ecology and Environment
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• 제30권3호
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• pp.271-276
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• 2007

A simple and efficient protocol was developed for culturing Cu-tolerant and Cu-accumulating plants via pre-adaptation to Cu during plant tissue culture. We induced multiple shoots from begonia (Begonia evansiana Andr.) leaf explants on MS medium supplemented with naphtaieneacetic acid and benzyladenine. After 3 months, small plantlets were transferred to MS medium supplemented with $100{\mu}M\;CuCl_2$ for pre-adaptation to Cu and cultured for 5 months. Then, these plantlets were individually planted in pots containing artificial soil. An additional 500 mg of Cu dissolved in 1/4 strength MS solution was applied to each pot during irrigation over the course of 2 months. We planted pre-adapted and control begonias in soil from the II-Kwang Mine, an abandoned Cu mine in Pusan, Korea, to examine their ability to tolerate and accumulate Cu for phytore-mediation. Pre-adapted begonias accumulated $1,200{\mu}g$ Cu/g dry root tissue over the course of 45 days. On the other hand, non-Cu-adapted controls accumulated only $85{\mu}g$ Cu/g dry root tissue. To enhance Cu extraction, chelating agents, ethylenediamine tetraacetic acid (EDTA)-dipotassiun and pyridine-2,6-dicarboxylic acid (PDA), were applied. While the chelating agents did not enhance accumulation of Cu in the roots of control begonias, EDTA application increased the level of Cu in the roots of pre-adapted begonias twofold (to $2,500{\mu}g$ Cu/g dry root tissue). Because pre-adapted begonias accumulated a large amount of Cu, mainly in their roots, they could be used for phytostabilization of Cu-contaminated soils. In addition, as a flowering plant, begonias can be used to create aesthetically pleasing remediation sites.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권1호
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• pp.94-103
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• 2016

Landfarming that supplies aerobic biodegradation condition to indigenous microbes in soils is a biological remediation technology. In this research, volatilization and biodegradation rate by indigenous microbes in the soil contaminated with total petroleum hydrocarbons (TPH) were measured. Soils were contaminated with diesel artificially and divided into two parts. One was sterilized by autoclave to remove indigenous microorganism and the other was used as it was. Various moisture contents and number of tillings were applied to the soil to find out proper condition to minimize volatilization and enhance bioremediation. Volatilization of TPH was inhibited and biodegradation was enhanced by increase on moisture content. Tilling was usually used to supply air for microbes, but tillings did not affect the growth of microbes in our study. Enough moisture content and proper aeration are important to control volatilization in landfarming. Also, TPH degradation was a function of the microbe counts (x₁), numbers of tilling (x₂), and moisture content (x₃) from the application of the response surface methodology. Statistical results showed the order of significance of the independent variables to be microbe counts > numbers of tilling > moisture content.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.234-243
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• 2021

In the research or project planning for the decommissioning of a nuclear power plant, one of several preparations will be the establishment of a list of potential radionuclides to be considered at the time of characterization or final status surveys. Reliable data for selection of potential radionuclides during the transition period to prepare for decommissioning will depend heavily on historical data at the site or, where possible, sampling analysis. However, during the transition period, direct sampling can be challenging, depending on the circumstances of the site or national regulation. A methodology of selecting potential radionuclides for nuclear facility sites which largely consists of three major processes: production of initial list of radionuclides, selection of the insignificant radionuclide that will be eliminated, and consideration of site characterization or sampling. For developing a preliminary list of potential radionuclides for Kori Unit 1 decommissioning, the list of initial radionuclides was made referring to the technical documents applied at decommissioned NPPs in the U.S and additional reference materials applied until the operation of NPPs in Korea. For the screening of insignificant radionuclides, we applied criterion of less than 0.1% of the amount of radioactivity inventory and confirmed the dose fraction using the RESRAD code. The final suit of radionuclides was established, which should be supplemented by reflecting site characterization and sampling process in the future. Thus, the methodology and results for the selection of potential radionuclides suggested in this paper can give an insight as a future reference to deriving DCGLs in relation to site remediation of decommissioning nuclear plants.

• 한국농공학회논문집
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• 제64권2호
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• pp.37-45
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• 2022

In-situ pilot experiment was carried out to establish a countermeasure on the soil loss from the hill side uplands that was rehabilitated by soil remediation method nearby abandoned mine sites for 2 years. It was considered that the affect of an inclination of cover surface, a stabilization treatment of cover layer by lime and steel refining slag (SRS) and a vegetation of soil surface as an effect factors in the experiment. It was constructed 4 lysimeters (plots, 22 m long, 4 m width) on the hilly side (37% inclination). One plot was control and two plots was treated by 1% lime and SRS. A remind one plot was modified a inclination to 27% to compare the affect of inclination on the amount of cover soil loss. It was attached a reservior tank and water level gauge in the end of lysimeters to measure the amount of the surface water flow and soil loss. It was also installed the automated sensors that could be collect the precipitation, soil moisture content, tension of cover layer in each plots. It was observed that the event of precipitation were caused the soil loss and it were related the physical and chemical properties of cover soil and inclination of surface layer of plots. During the experiment, it was exceeded the national regulation (50 t/ha/yr) in 37% inclination plots even though it was vegetated on the cover soil surface. However, in 27% inclination plot, it was shown that the amount of soil loss was maintained below the national regulation and, more ever, vegetation could reduce the the amount of soil loss. Therefore it was expected that such results could be applied to the future design of rehabilitation projects on the polluted farmland nearby abandoned mine sites.

• 한국환경과학회지
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• 제32권1호
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• pp.57-65
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• 2023

The advanced oxidation treatment using persulfate and zero-valent iron (ZVI) has been evaluated as a very effective technology for remediation of soil and groundwater contamination. However, the high rate of the initial reaction of persulfate with ZVI causes over-consumption of an injected persulfate, and the excessively generated active species show a low transfer rate to the target pollutant. In this study, ZVI was modified using selenium with very low reactivity in the water environment with the aim of controlling the persulfate activation rate by controlling the reactivity of ZVI. Selenium-modified ZVI (Se/ZVI) was confirmed to have a selenium coating on the surface through SEM/EDS analysis, and low reductive reactivity to trichlroethylene (TCE) was observed. As a result of inducing the persulfate activation using the synthesized Se/ZVI, the persulfated consumption rate was greatly reduced, and the decomposition rate of the model contaminant, anisole, was also reduced in proportion. However, the final decomposition efficiency was rather increased, which seems to be the result of preventing persulfate over-consumption. This is because the transfer efficiency of the active species (SO4-∙) of persulfate to the target contaminant has been improved. Selenium on the surface of Se/ZVI was not significantly dissolved even under oxidation conditions by persulfate, and most of it was present in the form of Se/ZVI. It was confirmed that the persulfate activation rate could be controlled by controlling the reactivity of ZVI, which could greatly contribute to the improvement of the persulfate oxidation efficiency.

• Smart Structures and Systems
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• 제31권4호
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• pp.335-349
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• 2023

Bridges constantly undergo deterioration and damage, the most common ones being concrete damage and exposed rebar. Periodic inspection of bridges to identify damages can aid in their quick remediation. Likewise, identifying components can provide context for damage assessment and help gauge a bridge's state of interaction with its surroundings. Current inspection techniques rely on manual site visits, which can be time-consuming and costly. More recently, robotic inspection assisted by autonomous data analytics based on Computer Vision (CV) and Artificial Intelligence (AI) has been viewed as a suitable alternative to manual inspection because of its efficiency and accuracy. To aid research in this avenue, this study performs a comparative assessment of different architectures, loss functions, and ensembling strategies for the autonomous segmentation of bridge components and damages. The experiments lead to several interesting discoveries. Nested Reg-UNet architecture is found to outperform five other state-of-the-art architectures in both damage and component segmentation tasks. The architecture is built by combining a Nested UNet style dense configuration with a pretrained RegNet encoder. In terms of the mean Intersection over Union (mIoU) metric, the Nested Reg-UNet architecture provides an improvement of 2.86% on the damage segmentation task and 1.66% on the component segmentation task compared to the state-of-the-art UNet architecture. Furthermore, it is demonstrated that incorporating the Lovasz-Softmax loss function to counter class imbalance can boost performance by 3.44% in the component segmentation task over the most employed alternative, weighted Cross Entropy (wCE). Finally, weighted softmax ensembling is found to be quite effective when used synchronously with the Nested Reg-UNet architecture by providing mIoU improvement of 0.74% in the component segmentation task and 1.14% in the damage segmentation task over a single-architecture baseline. Overall, the best mIoU of 92.50% for the component segmentation task and 84.19% for the damage segmentation task validate the feasibility of these techniques for autonomous bridge component and damage segmentation using RGB images.

• 한국지반공학회논문집
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• 제24권6호
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• pp.17-25
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• 2008

폐금속 광산 지역 등지에서 중금속으로 오염된 지하수의 정화 및 오염확산 방지를 위하여 투수성 반응벽체를 사용 할 수 있다. 본 연구에서는 슬래그가 투수성 반응벽체 충진물질로서 적당한지 평가하기 위하여 폐광산 지역에서 문제가 되고 있는 몇 가지 중금속(i.e., Pb, Cu, Cd)에 대한 슬래그의 반응성을 평가하였다. 폐광산 지역 지하수에는 중금속류들이 복합오염의 형태로 존재하며, 음이온 물질인 황산염, 탄산염 등도 공존한다. 중금속으로 오염된 현장의 조건을 고려하여, 1) 중금속 종류에 따른, 2) 초기 농도에 따른, 3) 음이온(황산염)의 존재에 따른 영향을 회분식 실험을 통하여 슬래그의 흡착능을 평가하였다. 슬래그의 흡착특성은 등온흡착평형(equilibrium sorption)과 동적인 흡착(kinetic sorption)인 경우 각 조건에 따른 영향을 확인하였다.

• 대한한의학회지
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• 제33권4호
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• pp.60-68
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• 2012

Objectives: By grasping trends in research, technology, and general characteristics of learning support tools, this study was conducted to present a model for research on Korean Medicine (KM) to make use of information technology to support teaching and learning. The purpose is to improve the future clinical competence of medical personnel, which is directly linked to national health. Methods: With papers and patents published up to 2011 as the objects, 438 papers were extracted from "Web of Science" and 313 patents were extracted from the WIPS database (DB). Descriptive analysis and network analysis were conducted on the annual developments, academic journals, and research fields of the papers, patents searched were subjected to quantitative analysis per application year, nation, and technology, and an activity index (AI) was calculated. Results: First, research on medical learning support tools has continued to increase and is active in the fields of computer engineering, education research, and surgery. Second, the largest number of patent applications on medical learning support tools were made in the United States, South Korea, and Japan in this order, and the securement of remediation technology-centered patents, rather than basic/essential patents, seemed possible. Third, when the results of the analysis of research trends were comprehensively analyzed, international research on e-PBL- and medical simulation-centered medical learning support tools was seen to expand continuously to improve the clinical competence of medical personnel, which is directly linked to national health. Conclusions: The KM learning support tool model proposed in the present study is expected to be applicable to computer-based tests at KM schools and to be able to replace certain functions of national KM doctor license examinations once its problem DB, e-PBL, and TKM simulator have been constructed. This learning support tool will undergo a standardization process in the future.

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권spc호
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• pp.40-54
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• 2023

산업혁명 이후 화석연료의 광범위한 사용, 삼림 벌채, 토지사용의 변화 등과 같은 인위적 활동은 대기 중 온실가스(GHGs, greenhouse gases) 농도를 지속적으로 증가시켜 지구의 기후위기를 유발하였다. 우리나라의 경우 최근 30년 사이 평균 온도가 1.4℃ 상승하였으며, 국제사회의 일원으로 책임을 다하기 위해 2016년 11월 3일 파리협정을 비준하였다. 이에 파리협정의 목표인 산업화 이전 대비 지구 평균온도 상승을 2℃ 아래, 가능한 1.5℃ 아래로 억제하기 위해 2050년까지 CO₂ 순배출량을 0으로 만들어야 하며, 이를 위해 다양한 정책 마련과 함께 경제 및 사회 전반에 걸쳐 많은 노력이 경주되고 있는 실정이다. 탄소중립을 달성하기 위해서는 첫 번째로 GHGs 배출을 줄이고, 두번째로 대기에서 CO₂ 포집을 촉진하기 위해 현재 가동되는 다양한 산업분야의 생산 시스템을 개혁하는 것이 가장 중요한 과제로 고려되고 있다. 그동안 지하수토양 관련 연구분야에서는 지속가능성(sustainability), 복원성(resilience), 녹색성장(green growth) 등과 같은 사회적 요구에 부응하여, 녹색정화(green remediation), 자연 저감(natural attenuation), 탄소포집저장(carbon capture and sequestration), 지열발전등의 기술이 초기단계로 개발이 되고 연구가 되어 왔다. 이러한 기존 연구들은 탄소중립2050의 달성을 위해 고도화되어야하며, 추가적으로 자연 및 인위기원 탄소배출 연구, 토양의 역할을 고려한 저탄소 토지이용 기술, 광물탄산화 등의 연구 및 기술개발이 필요하다고 판단된다. 본 논문에서는 탄소중립2050의 간단한 내용과 함께, 이를 달성하기 위한 지하수토양 분야의 혁신기술 및 선도연구를 소개하였다.