• Steel and Composite Structures
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• v.44 no.1
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• pp.105-117
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• 2022

Impact resistance efficiency of the newly designed sandwich beam with a laterally arched core as bio-inspired by the woodpecker is numerically investigated. The principal components of the beam comprise a dual-core system sandwiched by the top and bottom laminated CFRP skins. Different materials, including hot melt adhesive, high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), epoxy resin (EPON862), aluminum (Al6061), and mild carbon steel (AISI1018), are considered for the side-arched core layer of the beam for impact efficiency assessment. The aluminum honeycomb takes the role of the second core. Contact force, stress, damage formation, and impact energy for beams equipped with different materials are examined. A diversity in performance superiority is noticed in each of these indicators for different core materials. Therefore, for overall performance appraisal, the impact resistance efficiency index, which covers several chief impact performance parameters, of each sandwich beam is computed and compared. The impact resistance efficiency index of the structure equipped with the AISI1018 core is found to be the highest, about 3-10 times greater than other specimens, thus demonstrating its efficacy as the optimal material for the bio-inspired dual-core sandwich beam system.

• Journal of Environmental Impact Assessment
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• v.27 no.1
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• pp.83-91
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• 2018

Media (bio-stone), aquatic macrophytes (Oenanthe javanica) and herbivorous cladoceran (Daphnia similoides) have been used in artificial floating island (AFI) systems for water pollution control. Efficiency in chl-a concentration controlling of AFI was tested using different combinations of each device: G-BD-mixture bio-stone and Daphnia similoides, G-OB-mixture Oenanthe javanica and bio-stone, G-BOD-mixture bio-stone, Oenanthe javanica and Daphnia similoides, and the out-put water quality improvement was compared with G-C-control (no device was applied). We analyzed removal efficiency of chl-a concentration and nutrient concentrations in the artificially eutrophic water in the laboratory experimental facility. The results showed average removal rates of Chlorophyll a, TN and TP for different four groups: 69.24%, 16.61%, -0.61%; 68.39%, 14.11%, 10.52%; 78.30%, 6.69%, 25.09%; 35.42%, -3.47%, -25.18%, respectively. The results have suggested that the mixture of media, plants and zooplankton is the most efficient combination for Chlorophyll a control, while the mixture of macrophytes and bio-stone have better efficiency nutrient control.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.333-341
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• 2017

Recently, the earth has shown the limit of environmental capacity. It is also experiencing an environmental crisis with rising energy prices and depletion of coal. Therefore, development of renewable energy is very important solution. However, waste fuel solid are renewable fuels, but they cause environmental problems. In this study, the emission characteristics of hazardous air pollutants were analyzed through measurements at the facilities using solid fuels (SRF, BIO-SRF). Analysis method of PAHs are based on the Korea Standard Methods for Examination. The analysis of PAHs showed that the concentration much higher in Naphthalene, and Benzo(a)pyrene showed at a higher concentration incertain sources. As a result of gas phase and particle phase PAHs, most of Benzo(a)pyrene appeared to be particulate. Through the results of this study will provide basic data for atmospheric environmental management.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.100-104
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• 2015

Adverse effect of veterinary antibiotics (VAs) released into environment has been issued recently and concerns about analysis and management for VAs in the environment were increased. Main objective of this research was to calculate predicted environmental concentration (PEC) of the VAs in soil based on avaiable statistical data and result of previous study such as consumption rate and physiological properties of VAs. Total of 5 VAs, Chlortetracycline (CTC), Oxytetracycline (OTC), Sulfadimethoxine (SDX), Sulfamethazine (SMT), and Tylosin (TYL) were examined. Result showed that calculated PEC value in manure and soil was ordered as SMT > TYL > SDX > CTC > OTC. Range of calculated value for manure and soil was 0.50-67.04 and $0.48-64.45mg\;kg^{-1}$ respectively. Comparing to measured concentration of VAs in manure and soil, lower concentration of VAs in manure and soil was evaluated due to fate and degradation of VAs in manure and soil. Overall, evaluated simple modeling for calculating PEC of VAs in manure and soil can be adapted for preliminary screening purpose in environmental risk assessment and more refined modeling is necessary to examine detailed assessment of VAs in manure and soil.

• Journal of Korean Society of Rural Planning
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• v.20 no.4
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• pp.13-24
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• 2014

The pond wetlands in agricultural landscape are important natural resources that carry out the function of bio-diversity conservation. However, recently, those have been gradually embedded as their utility value were disappeared. And, the assessment methods used for pond wetlands are insufficient. Therefore, this study was conducted to examine the conservation value of pond wetlands by using the modified RAM, and present the improvement of assesment methods. The study sites, a total of 32 pond of 4 types by land use, were selected on the basis of Ramsar Convention. Through the analysis of precedent studies, the weighted 8 functions were adjusted. According to the assessment results, pond wetlands made the largest contribution to Fishery and Herpetile Habitat function. In addition, it also made large contribution to Floral Diversity, Wildlife Habitat, and Water Quality Protection function. On the other hand, it made a small contribution to Aesthetics and Recreation, Runoff Attenuation, Shoreline /Stream Bank Protection, and Flood/Storm Water Storage function due to the characteristics of small-scale pond wetlands. In the assessment of 8 functions, house type showed the worst assessment result, and mountain type showed the best assessment result. It is thought that those are due to land use type in terms of vicinity. 10 items among 52 of the modified RAM showed the same assessment results in all land use types. Accordingly, it is required to be deleted and modified the assessment method. On the other hand, it is required to add age, interference, and water use to the assessment method. It is thought that these results can be utilized for the development and modification of assessment methods focused on pond wetlands in rural area.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.257-260
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• 2006

West coast of Korea belongs to the five largest tidal-flat zones in the world. Aiming at the efficient management and preservation of the eco-system and the enhancement of the bio-productivity of the tidal-flat zones, development of a environment-friendly vehicle for tidal-flat area is being attempted. This paper deals with the description of the characteristics of the tidal-flat zones of west coast of Korea, the technology assessment of the related products in the ATV(All-Terrain Vehicle) market, the demand assessment for the resident people.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.177-184
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• 2021

While veterinary antibiotics are used only in a part of the dose administered, the rest are excreted as urine or feces. Residual antibiotics enter the adjacent agricultural environments by spraying manure-based composts on farmlands and lead to secondary pollution. Therefore, it is necessary to develop the technique for post management such as regulatory levels of antibiotics in the agricultural environments. This study was conducted to compare by different matrices the amount of residual antibiotics such as tetracyclines and sulfonamides, which are known to be frequently used in Korea and to practice risk assessment by different antibiotics in soils before and after application of composts. Pre-treatment with modified typical method using buffer and solid phase extraction showed the recovery of composts and soils was more than 70% at ppb level and the limits of detection were 0.13-0.46 and 0.05-0.25 ㎍/kg, respectively. Analysis of manure-based composts revealed concentrations from 5.38 to 196.0 ㎍/kg for tetracyclines, from below the detection of limit (BDL) to 259.0 ㎍/kg for sulfonamides. In case of agricultural soils, residual concentrations of selected veterinary antibiotics were ranged 0.30-53.3 ㎍/kg, BDL-4.16 ㎍/kg respectively and the concentration level of tetracyclines, which had higher soil distribution coefficient (Kd) values, was higher than that of sulfonamides. There was a difference in human risk assessment by different antibiotics in soil before and after application of composts. But, it was indicated that detection values of all of 5 antibiotics were very safe on the basis that Hazard Quotient was safe below 1.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.2
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• pp.71-83
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• 2022

In this study, an indicator and assessment system for evaluating the monthly hydrological cycle was prepared using simple factors such as the landuse status of the watershed and topographic characteristics to the dynamic water balance model (DWBM) based on the Budyko framework. The parameters a1 of DWBM are introduced as hydrologic cycle indicators. An indicator estimation regression model was developed using watershed characteristics data for the introduced indicator, and an assessment system was prepared through K-means cluster analysis. The hydrological cycle assessment system developed in this study can assess the hydrological cycle with simple data such as land use, CN, and watershed slope, so it can quickly assess changes in hydrological cycle factors in the past and present. Because of this advantage is expected that the developed assessment system can predict changes in the hydrological cycle and use an auxiliary tool for policymaking.

• Journal of Environmental Impact Assessment
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• v.20 no.6
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• pp.815-821
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• 2011

This study aims to estimate the biological decomposition capacity of MPC(Microorganism Porous-Concrete). MPC has specific surface area formed by inside pores, and bio compound was added to those pores to reduce pollutants loading. To evaluate the water purification capacity of MPC, we carried out the comparative studies using different media types [GPC(General Porous-concrete), CPC(Compound porous-concrete), LPC(Lightweight aggregate porous-concrete)] under the condition of CFSTR, and different retention times (30, 60 and 120 min). We also estimated the purification capacity of MPC under different concentrations of pollutant loadings. The MPC showed higher efficiency in water purification function than other conventional porous concretes with efficient decrease rates of SS, BOD, COD, and nutrient concentrations. In the comparison experiment for different retention times, MPC showed the highest removal efficiency for all tested pollutants in the longest retention time(120 min). In the long period test, the removal efficiencies of MPC concrete were high until 100 days after the set up of the operation, but began to decrease. Outflow flux was invariable compared with inflow flux so that extra detention time for media fouling such as back washing is not needed. But the results suggested that appropriate management is necessary for long-term operation of MPC. As the final outcome, MPC using bio organisms is considered to be efficient for stream water purification when they used as substrates for artificial river structure.

• New & Renewable Energy
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• v.3 no.4
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• pp.98-103
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• 2007

국제 원유가의 지속적인 상승에 따라 화석연료 고갈을 대비한 대체에너지 및 온실가스배출 감소를 위하여 바이오연료의 시용 및 상용보급은 전세계적인 추세이다. 우리나라의 경우 바이오디젤은 2002년부터 시범보급사업(Demonstration & disseminatio을 거쳐 2000년 7월부터 전국주유소를 통하여 경유 중에 바이오디젤 0.5%를 혼합한 BD0.5를 수송용 연료로 도입하여 아시아 최초로 상용보급화를 시행하고 있다. 또한 휘발유 중 바이오에탄올 혼합 연료유 도입을 위한 실증평가연구를 2006년 8월부터 2008년 7월까지 수행중이다. 자동차용 휘발유의 옥탄가 향상을 위해 함산소 기재로 사용되는 MTBE(Methyl Tertiary Butyl Ether)를 바이오에탄올로 대체한 바이오에탄올 혼합연료유는 수분 혼입에 의한 상 분리(Phase separation)와 금속에 대한 부식성 문제를 야기 시킬 수 있다. 바이오에탄올을 서브옥란가솔린(Sub-octane gasoline)에 혼합하여 상 분리 모사실험, 금속류 부식시험, 고무류 침지실험 등 다양한 품질특성평가를 수행하였으며, 이런 결과들을 바탕으로 국내실정에 알맞은 최적의 혼합량(E3, E5)을 도출하였다. 또한 전국에 4개 시범주유소를 운영하여 바이오에탄올 혼합 연료유의 유통 및 보급을 통해 최적의 유통인프라(Distribution infrastructure) 보완 및 구축 방안을 도출 하고자 한다.