전형순 Jun Hyung Soon , 남기성 Nam Ki Sung

DOI: JKWST Vol.55(No.1) 1-8, 2013

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This study will not only prove experimental dynamic properties which are classified to slump, compressive strength, tensile strength, flexure strength and toughness granite soil concrete with a fine aggregate of granite soil and blast-furnace cement and polypropylene fiber over 45 mm, but also establish a basic data in order to use environment-friendly pavement through prove useful pavement mixed with granite and polypropylene (PP) fiber which is a kind of material to prevent a dry shrinkage clack, a partial destruction and useful and light. The value of slump test was gradually increased by PP fiber volume 3 kgf/m³, but compressive strength took a sudden turn for the worse from 5 kgf/m³. The compressive strength indicated a range of 13.72∼18.35 MPa. On the contrary to compressive strength, the tensile strength showed to decrease with rising PP fiber volume, and the tensile strength indicated a range of 1.43∼ 1.64 MPa. The tensile strength was stronger about 2∼15 % in case of mixing with PP fiber volume than normal concrete. The flexural strength indicated a range of 2.76∼3.41 MPa. The flexural strength was stronger about 20 % in case of PP fiber volume 0 kg/m³ than PP fiber volume 9 kg/m³. The toughness indicated a range of 0∼25.46 N · mm and increased proportionally with PP fiber volume. The toughness was stronger about 8.3 times in case of PP fiber volume 9 kg/m³ than PP fiber volume 1 kg/m³. The pavement with PP fiber volume over such a fixed quantity in the park roads and walkways can have a effect to prevent not only resistance against clack but also rip off failures.

김시수 Kim Si Soo , 정충길 Jung Chung Gil , 박종윤 Park Jong Yoon , 정성원 Jung Sung Won , 김성준 Kim Seong Joon

DOI: JKWST Vol.55(No.1) 9-15, 2013

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This study is to evaluate the parameter behavior of VfloTM distributed rainfall-runoff model by applying 3 kinds of rainfall interpolation methods viz. Inverse Distance Weighting (IDW), Kriging (KRI), and Thiessen network (THI). For the 1,544 km² Dongcheon watershed of Nakdong river, the model was calibrated using 4 storm events in 2007 and 2009, and validated using 2 storm events in 2010. The model was calibrated with Nash-Sutcliffe model efficiency of 0.97 for IDW, 0.94 for KRI, and 0.95 for THI respectively. For the sensitive parameters, the saturated hydraulic conductivity (K_sat) for IDW, KRI, and THI were 0.33, 0.31, and 0.43 cm/hr, and the soil suction head at the wetting front (Ψf) were 4.10, 3.96, and 5.19 cm H₂O respectively. These parameters affected the infiltration process by the spatial distribution of antecedent moisture condition before a storm.

전지홍 Jeon Ji-hong , 다니엘차 Cha Daniel K. , 최동혁 Choi Donghyuk , 김태동 Kim Tae-dong

DOI: JKWST Vol.55(No.1) 17-29, 2013

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Long-Term Hydrologic Impact Assessment (L-THIA) model which is a distributed watershed model was applied to analyze the spatial distribution of surface runoff and nonpoint source pollutant loading from Imha watershed during 2001～2010. L-THIA CN Calibration Tool linked with SCE-UA was developed to calibrate surface runoff automatically. Calibration (2001～2005) and validation (2006～2010) of monthly surface runoff were represented as ‘very good’ model performance showing 0.91 for calibration and 0.89 for validation as Nash-Sutcliffe (NS) values. Average annual surface runoff from Imha watershed was 218.4 mm and Banbyun subwatershed was much more than other watersheds due to poor hydrologic condition. Average annual nonpoint source pollutant loading from Imha wateshed were 2,295 ton/year for BOD5, 14,752 ton/year for SS, 358 ton/year for T-N, and 79 ton/year for T-P. Amount of pollutant loading and pollutant loading rates from Banbyun watershed were much higher than other watersheds. As results of analysis of loading rate from grid size (30 m×30 m), most of high 10 % of loading rate were generated from upland. Therefore, major hot spot area to manage nonpoint source pollution in Imha watershed is the combination of upland and Banbyun subwatershed. L-THIA model is easy to use and prepare input file and useful tool to manage nonpoint source pollution at screening level.

김성재 Kim Sung Jae , 김성민 Kim Sung Min , 김상민 Kim Sang Min

DOI: JKWST Vol.55(No.1) 31-38, 2013

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The purpose of this study was to evaluate climate change vulnerability over the agricultural infrastructure in terms of flood and drought using principal component analysis. Vulnerability was assessed using vulnerability resilience index (VRI) which combines climate exposure, sensitivity, and adaptive capacity. Ten flood proxy variables and six drought proxy variables for the vulnerability assessment were selected by opinions of researchers and experts. The statistical data on 16 proxy variables for the local governments (Si, Do) were collected. To identify major variables and to explain the trend in whole data set, principal component analysis (PCA) was conducted. The result of PCA showed that the first 3 principal components explained approximately 83 % and 89 % of the total variance for the flood and drought, respectively. VRI assessment for the local governments based on the PCA results indicated that provinces where having the relatively large cultivation areas were categorized as vulnerable to climate change.

박진기 Park Jin Ki , 박종화 Park Jong Hwa

DOI: JKWST Vol.55(No.1) 39-48, 2013

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The solar radiation is the primary energy source that drives many of the earth's physical and biological processes and climate change. Understanding its importance to the solar radiation observation is a key to understanding a broad range of natural processes, agricultural, energy and human activities. The purpose of this study is to estimate solar radiation using sunshine duration, and to estimate distribution of solar radiation using a topography factor considering surface slope and aspect in complex terrain. The result of regression analysis between ratio of solar radiation and sunshine duration from 2001 to 2010 shows high R² value of 0.878. Regression analyses indicated that topographic attributes including elevation, slope and aspect had significant effects on solar radiation. The variation of topographic factor with aspect and slope for the summer and winter are considered. The highest month of daily mean solar radiation at Jeju island appears in April of 20.61 MJ · m^-2 · day^-1, and the lowest month appears in December of 6.90 MJ · m^-2 · day^-1. These results provided useful quantitative information about the influence of topography on solar radiation in the island region.

강구 Kang Ku , 김영기 Kim Young-kee , 박성직 Park Seong-jik

DOI: JKWST Vol.55(No.1) 49-57, 2013

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The present study was conducted to investigate phosphate removal from aqueous solution using industrial wastes, red mud (RM), acid treated red mud (ATRM) and converter furnace steel slag (CFSS). The chemical composition of adsorbents was analyzed using X-ray fluorescence (XRF). Batch experiments and elution experiments using water tank were performed to examine environmental factors that influences on phosphate removal. Kinetic sorption data of RM, ATRM, and CFSS were described well by the pseudo second-order kinetic sorption model, and equilibrium sorption data of all adsorbents obeyed Freundlich isotherm model. The adsorption capacities of adsorbents followed order: ATRM (7.06 mg/g)＞RM (4.34 mg/g)＞CFSS (1.88 mg/g). Increasing pH from 3 to 11, the amount of adsorbed phosphate on all RM, ATRM, and CFSS were decreased. The presence of sulfate and carbonate decreased the phosphate removal of RM and ATRM but did not influence on the performance of CFSS. The phosphate removal of RM, ATRM, and CFSS was greater in seawater than deionized water, resulting from the presence of cations in seawater. The water tank elution experiments showed that RM capping blocked the elution of phosphate effectively. It was concluded that the adsorbents can be successfully used for the removal of the phosphate from the aqueous solutions.