• Clean Technology
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• v.16 no.1
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• pp.12-18
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• 2010

The object of the present study is to apply KF/MgO catalysts to remove sulfur dioxide from dibenzothiophene sulfone, a by-product of oxidative desulfurization. Potassium fluoride was deposited via an impregnation method on MgO. The effects KF loading and calcination on the characteristics of the KF/MgO catalysts were investigated through the BET surface area, XRF, XRD, and temperature-programmed desorption of $CO_2$. The catalytic performances of the samples were investigated during the decomposition of dibenzothiophene sulfone to biphenyl and sulfur dioxide gas. KF loaded on MgO prepared by the impregnation method showed high catalytic activities for the decomposition of dibenzothiophene sulfone. The higher activity of KF/MgO just dried at 373 K, avoiding the usual activation at high temperature, than that over the calcined catalyst is ascribed to increase of the amount of basic sites. The high basicity probably may be due to the coordinately unsaturated $F^-$. The simply dried 10 % KF/MgO catalyst, without the usual activation at high temperature, showed the optimal catalytic properties.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.57-65
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• 2008

Joint of concrete pavement contributes to improvement of pavement performance by preventing occurrence of random cracking due to drying shrinkage and temperature changes of concrete slabs at early age. However, saw-cutting operations performed prior to sufficient concrete hardening develop micro-cracking of the concrete near the joints, which may develop to long-term distresses due to repetitious traffic and environmental loadings. To reduce the distresses, the joint crack inducers with heights of 100 mm, 150 mm, and 220 mm and the joint cracking slots with various depth were installed at a test section to investigate occurrence of the joint cracks and their behaviors over 5 months. As the results, higher efficiency of the crack inducing and larger behavior of the joint cracks were observed for the taller joint crack inducer. Higher efficiency of the crack inducing and improvement of the joint performance are warranted by additional investigation and reformation of the joint crack inducer.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.218-219
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• 2022

The Korea Institute for Advancement of Technology and the Ulsan ICT Promotion Agency are building an electric smart ship using a full range of ICT with advanced technology, and are expected to demonstrate it in 2022. For the demonstration of onboard ship equipment, it needs to develop a demonstration procedure. There are 4 types of onboard equipment preferentially selected for the development of the demonstration test procedure which are an electronic chart display and information system, a ship RADAR system, a voyage data recorder, and a ship energy efficiency monitoring system. This paper describes the demonstration procedure based on the equipment standard for the electronic chart display and information system among 4 selected types of demonstration equipment, and also the verification test checklist and template is introduced.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.103-103
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• 2020

눈개승마 (Aruncus dioicus)는 장미과(Rosaceae) 눈개승마속(Aruncus)에 속하는 다년생 초본식물로 울릉도에서 자생하는 잎줄기 채소이다. 독특한 향기가 특징이며, 인삼맛, 두릅맛, 고기맛이 나는 산채로 세가지 맛이 난다고 하여 예로부터 삼나물로도 불러왔다. 눈개승마에는 caffeic acid, 1-O-Caffeoyl-β-D-glucopyranose 등의 항산화 성분이 다량 함유되어 있으며, 전초는 해독, 편도선염에 효과가 있어 약용으로 쓰이고 어린순은 탄수화물과 무기물 함량이 풍부하다. 비지는 대두를 이용하여 두부를 제조하는 과정에서 발생되는 것으로서 대두로부터 수용성 단백질이 추출되었지만 나머지 약 23%의 단백질, 57%의 식이섬유와 이소플라본 등의 유용한 성분을 다량 포함하고 있다. 또한 비지의 단백질은 다른 식품에는 부족한 황 함유 아미노산과 리신의 함량이 비교적 많고, 두부에 거의 없는 식이섬유가 다량 함유된 고 식이섬유 소재이다. 그리하여, 이러한 콩비지를 고부가가치 식품 소재로 활용하기 위해 건조 미세분말 비지를 제조하고, 이를 산채와의 혼합 가공을 통한 기능증진 효과를 연구하였다. 일반적으로 산채는 쓴맛 제거와 보관성 증진을 위해 데침공정을 주로 하나 산채를 물에 데칠 경우 산채의 유용성분이 대부분 손실된다. 눈개승마의 경우 유용성분이 17.25%, 그 중 폴리페놀 성분이 약 90% 손실된다. 본 연구에서는 기존의 데침공정 대신 찜공정을 이용하여 산채의 유용성분을 보존하고 콩비지를 첨가하여 산채 유용성분의 생이용성 증진 효과를 연구하였다. 눈개승마를 콩비지와 혼합하여 고온고압 가공함으로써 산채의 쓴맛을 줄이고 보관성을 높이는 동시에 눈개승마 폴리페놀의 단량체화를 통해 눈개승마 단독가공에 비하여, 단량체 비율이 약 100~200배 증가하는 것을 확인하였다. 본 연구를 통하여 콩비지의 고부가가치 소재로의 가능성을 확인하였을 뿐만 아니라 산채의 다이어트·건강기능식품 소재로의 산업화에도 기여할 수 있을 것으로 기대된다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.106-114
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• 2006

This paper investigates the fundamental properties and shrinkage characteristics of low shrinkage high performance concrete(LSHPC), using mock-up specimens. According to the test results, the most suitable mix proportions of LSHPC need a higher dosage of SP agent and AE agent, in order to obtain the target of slump flow and air content. This is due to reduce fluidity and air content respectively. It also presented earlier setting time than control concrete by 6 hours and exhibited compressive strength of 60MPa at age 28 days. Autogenous shrinkage of LSHPC was the half of the value of control concrete. Drying shrinkage of center section of LSHPC showed similar tendency with autogenous shrinkage, because of no internal moisture movement, while surface section had larger drying shrinkage. The specimen with embedded reinforcing bar had smaller deformation owing to confinement of reinforcing bar.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.496-523
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• 2018

The objective of this study is to evaluate the economic feasibility of two fast pyrolysis and biooil upgrading (FPBU) plants including feed drying, fast pyrolysis by fluidized-bed, biooil recovery, hydro-processing for biooil upgrading, electricity generation, and wastewater treatment. The two FPBU plants are Case 1 of an FPBU plant with steam methane reforming (SMR) for $H_2$ generation (FPBU-HG, 20% yield), and Case 2 of an FPBU with external $H_2$ supply (FPBUEH, 25% yield). The process flow diagrams (PFDs) for the two plants were constructed, and the mass and energy balances were calculated, using a commercial process simulator (ASPEN Plus). A four-level economic potential approach (4-level EP) was used for techno-economic analysis (TEA) under the assumption of sawdust 100 t//d containing 40% water, 30% equity, capital expenditure equal to the equity, $H_2$ price of $1050/ton, and hydrocarbon yield from dried sawdust equal to 20 and 25 % for Case 1 and 2, respectively. TCI (total capital investment), TPC (total production cost), ASR (annual sales revenue), and MFSP (minimum fuel selling price) of Case 1 were $22.2 million, $3.98 million/yr, $4.64 million/yr, and $1.56/l, respectively. Those of Case 2 were $16.1 million, $5.20 million/yr, $5.55 million/yr, and $1.18/l, respectively. Both ROI (return on investment) and PBP (payback period) of Case 1(FPBU-HG) and Case 2(FPBU-EH) were the almost same. If the plant capacity increases into 1,500 t/d for Case 1 and Case 2, ROI would be improved into 15%/yr.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.57-64
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• 2006

The crack presented in concrete structures causes a structural defect, the durability decrease, and external damages etc. Therefore, it is necessary to improve durability through the effort to control the crack. Fluosilicic acid($H_2SiF_6$) is recovered as aqueous solution which absorbs $SiF_4$ produced from the manufacturing of industrial-graded $H_3PO_4$ or HF. Generally, fluosilicates prepared by the reaction between $H_2SiF_6$ and metal salts. Addition of fluosilicates to cement endows odd properties through unique chemical reaction with the fresh and hardened cement. Mix proportions for experiment were modulated at 0.45 of water to cement ratio and $0.0{\sim}2.0%$ of adding ratio of fluosilicate salt based inorganic compound. To evaluate correlation of concrete strength and adding ratio of fluosilicate salt based inorganic compound, the tests were performed about design strength(21, 24, 27 MPa) with 0.5% of adding ratio of fluosilicate salt based inorganic compound. Applications of fluosilicate salt based inorganic compound to reduce cracks resulted from plastic and drying shrinkage, to improve durability are presented in this paper. Durability was evaluated as neutralization, chloride ion penetration depth, freezing thawing resistant tests and weight loss according reinforcement corrosion. It is ascertained that the concrete added fluosilicate salt based inorganic compound showed m ability to reduce the total area and maximum crack width significantly as compared non-added concrete. In addition, the durability of concrete improved because of resistance to crack and watertightness by packing role of fluosilicate salt based inorganic compound obtained and pozzolanic reaction of soluble $SiO_2$ than non-added concrete.

• Horticultural Science & Technology
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• v.17 no.4
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• pp.500-502
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• 1999

This study was carried out to survey the distribution of Korean native Sedum rotundifolium and environmental conditions of their native habitats. Sedum rotundifolium could be found only at the Mt. Juwang and its vicinity, Okgae valley. And most of Sedum rotundifolium plants in habitats were positioned between the chasm of cliffs in middle mountainous area having altitudes ranging about 250~450 m. Most of soil conditions in native habitats were somewhat arid, and light intensities were ranged from 1 to 90 % of those at the open area. But relative humidity, air temperature and soil temperature showed little difference compared with those of open area. Soil acidities were ranged from pH 5.0 to 7.0, and relatively high amount of humus, total $P_2O_5$, Ca, and Mg were measured at habitat area. On the other hand, growth of Sedum rotundifolium was significantly different according to habitat sites.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.183-192
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• 2005

Natural ventilation in radioactive waste repositories is considered to be less efficient than mechanically forced ventilation for the repository working environment and hygiene & safety of the public at large, for example, controlling the exposure of airborne radioactive particulate matter. It is, however, considered to play an important role and may be fairly efficient for maintaining environmental conditions of the repository over the duration of its lifetime, for example, moisture content and radon (Rn) gas elimination in repository. This paper describes the feasibility of using natural ventilation which can be generated in the repository itself, depending on the conditions of the natural environment during the periods of repository construction and operation. Evidences from natural cave analogues, actual measurements of natural ventilation pressures in mountain traffic tunnels with vertical shafts, and calculations of airflow rates with given natural ventilation pressures indicate possible benefits from passive ventilation for the prospective Korean radioactive waste repository. Natural ventilation may provide engineers with a cost-efficient method for heat and moisture transfer, and radon (Rn) gas elimination in a radioactive waste repository. The overall thermal performance of the repository may be improved. The dry-out period may be extended, and the seepage flux likely would be decreased.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.965-974
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• 2009

This study evaluated the degradation efficiency of malodorous sulfurized-organic compounds by utilizing N- and Sdoped titanium dioxide under visible-light irradiation, and examined the catalyst deactivation and regeneration. Catalyst surface was characterized by employing Fourier-Transform-Infrared-Red (FTIR) spectra. The visible-light-driven photocatalysis techniques were able to efficiently degrade low-level dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) with degradation efficiencies exceeding 97%, whereas they were not effective regarding the removal of high-level DMS and DMDS, with degradation efficiencies of 84 and 23% within 5 hrs of photocatalytic processes. As compared with DMS, DMDS which containes one more sulfur element revealed quick catalyst deactivation. Catalyst deactivation was confirmed by the equality between input and output concentrations of DMD or DMDS, the obsevation of no $CO_2$ generation during a photocatalytic process, and the FTIR spectrum peaks related with sulfur ion compounds, which are major byproducts formed on catalyst surfaces. The mineralization efficiency of DMS at 8 ppm, which was a peak value during a photocatalytic process, was calculated as 144%, exceeding 100%. The catalyst regenerated by high-temperature calcination exhibited higher catalyst recovery efficiency (53 and 58% for DMDS and DMS, respectively) as compared with dry-air and humid-air regeneration processes. However, even the calcined method was unable to totally regenerate deactivated catalysts.