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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Agricultural Engineers
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The Korean Society of Agricultural Engineers
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Volume & Issues
Volume 48, Issue 7 - Dec 2006
Volume 48, Issue 6 - Nov 2006
Volume 48, Issue 5 - Sep 2006
Volume 48, Issue 4 - Jul 2006
Volume 48, Issue 3 - May 2006
Volume 48, Issue 2 - Mar 2006
Volume 48, Issue 1 - Jan 2006
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Chemical Properties in the Soils of Reclaimed and Natural Tidelands of Southwest Coastal Area of Korea (I) - Distribution of Heavy Metal Fractions -
Cho, Jae-Young ; Koo, Ja-Woong ; Son, Jae-Gwon ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 3~10
DOI : 10.5389/KSAE.2006.48.1.003
The chemical fractions of heavy metals were investigated in the soils of reclaimed and natural tidelands of southwest coastal area of Korea. The distribution pattern of each heavy metal in different fractions was in the order: 1) Cu : organic bound > organic complex > residual > exchangeable = water soluble. 2) Cr : residual > organic bound > organic complex > water soluble > exchangeable. 3) Pb : organic bound > residual > organic complex > water soluble > exchangeable. 4) Cd residual > organic bound > organic complex > water soluble = exchangeable. 5) Zn : organic bound > residual > organic complex > water soluble > exchangeable. The content of residual Zn showed positive correlation with organic matter content but organic bound Zn showed negative correlation with CEC. The content of residual and exchangeable Cd showed highly positive correlation with organic matter content but residual, organic bound, and exchangeable Cd showed negative correlations with CEC. Water soluble Pb showed positive correlation with CEC but organic bound Pb showed negative correlation with CEC.
Estimation of Paddy Rice Crop Coefficients for FAO Penman-Monteith and Modified Penman Method
Yoo Seung-Hwan ; Choi Jin-Yong ; Jang Min-Won ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 13~23
DOI : 10.5389/KSAE.2006.48.1.013
In 1998, Food and Agriculture Organization addressed that FAO Modified Penman method possibly over-estimates consumptive use of water comparing to the measured reference crop evapotranspiration (PET) and Penman-Monteith method can be better choice for accurate PET estimation. Nevertheless it is still difficult to find research efforts about paddy rice crop coefficient for Penman-Monteith method. This study aims to estimate paddy rice crop coefficients for Penman-Monteith and FAO modified Penman methods in the manner of comparing two equations. To estimate the crop coefficients, measured evapotranspiration data during 1982-1986 and 1995-1997 were used. The average Penman-Monteith crop coefficients ranged from 0.78 to 1.58 for translated paddy rice and from 0.87 to 1.74 for flood-direct seeded paddy rice. The average FAO Modified Penman crop coefficients ranged from 0.65 to 1.35 for translated paddy rice and from 0.70 to 1.58 for flood-direct seeded paddy rice.
Development of a Stream Discharge Estimation Program
Lee Sang Jin ; Hwang Man Ha ; Lee Bae Sung ; Ko Ick Hwan ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 27~38
DOI : 10.5389/KSAE.2006.48.1.027
In this study, we developed a program to estimate discharge efficiently considering major hydraulic characteristic including water level, river bed, water slope and roughness coefficient in a natural river. Stream discharge was measured at Gongju gauge station located in the down stream of the Daechung Dam during normal and dry seasons from 2003 to 2004. The developed model was compared with the results from the existing rating curve at T/M gage stations, and was used for runoff analyses. Evaluating the developed river discharge estimation program, it was applied during 1983-2004 that base flow separation method and RRFS (Rainfall Runoff Forecasting System) which is based on SSARR (Streamflow Synthesis And Resevoir Regulation). The result presents the stage-discharge curve creator range at the Gong-ju is overestimated by approximately
, especially at the low stage. It is attributed to the hydraulic characteristics at the study. The discharge simulated by the RRFS and base flow separation, which is calibrated using the measurement at the early spring and late fall season during relatively d]v season, shows the least errors. The coefficient of roughness at Gongju station varied with the high and low water level.
A Cultural Property Priority Assessment Using Information Measure Technique
Jung, Nam-Su ; Lee, Jeong-Jae ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 41~48
DOI : 10.5389/KSAE.2006.48.1.041
In the evaluation of rural amenities, its properties are related with social, cultural, and environmental elements. In this study, Information Measure Model (IMM) and Cultural Property Priority Assessment Model (CPPAM) were developed adapting information measure model with text based surveying data. To apply developed model not only general properties but also specific surveyed data, Specific Information Gathering and Utilizing System (SIGUS) was constructed using the data in Dusan World encyclopedia. IMM shows priorities of cultural property by information in national-designated cultural properties. And CPPAM applied in surveying data in 2004 by Rural Resources Development Institute.
Drying Shrinkage and Strength Properties of Polymer-Modified Mortars Using Redispersible Polymer Powder
Yeon, Kyu-Seok ; Joo, Myung-Ki ; Lee, Hyun-Jong ; Jin, Xing-Qi ; Lee, Chi-Won ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 51~60
DOI : 10.5389/KSAE.2006.48.1.051
This study was conducted to investigate experimentally the drying shrinkage and the strength properties of redispersible SBR and PAE powder-modified mortars. Polymer-cement ratio, content of shrinkage-reducing agent and antifoamer content were manipulated as the experimental variables. The peculiarity of this study is to obtain a high early-age strength by using the portland cement and alumina cement with the ratio of 8 : 2. Until 7 days of age, the drying shrinkage remarkably increased up to
, while it tended to decrease as the ratio of polymer to cement ratio and the content of shrinkage-reducing agent increased. Polymer-cement ratio was effective in improving the flexural, tensile and adhesive strengths: As the ratio increased, the strengths correspondingly increased. The flexural strength was in the range of
MPa, the tensile strength was
MPa and the adhesive strength was
MPa. On the other hand, the compressive strength tended to decrease as the polymer-cement ratio increased, and it was in the range of
MPa. All strengths, flexural, tensile, adhesive and compressive strengths, decreased as the content of powder shrinkage-reducing agent increased. It turned out that the polymer-cement ratio influenced more on the behavior of drying shrinkage and the properties of strength than the powder shrinkage-reducing agent did.
p-Version Nonlinear Finite Element Analysis of RC Slabs Strengthened with Externally Bonded CFRP Sheets
Cho, Jin-Goo ; Park, Jin-Hwan ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 61~68
DOI : 10.5389/KSAE.2006.48.1.061
The p-version nonlinear finite element model has been developed to analyze the nonlinear behavior of simply supported RC slabs strengthened with carbon fiber reinforced plastic sheets. The shape function is adopted with integral of Legendre polynomials. The compression model of concrete is based on the Kupfer's yield criterion, hardening rule, and crushing condition. The cracking behavior is modeled by a smeared crack model. In this study, the fixed crack approach is adopted as being geometrically fixed in direction once generated. Each steel layer has a uniaxial behavior resisting only the axial force in the bar direction. Identical behavior is assumed fur tension and compression of steel according to the elastic modulus. The carbon fiber reinforced plastic sheets are considered as reinforced layers of equivalent thickness with uniaxial strength and rigidity properties in the present model. It is shown that the proposed model is able to adequately predicte the displacement and ultimate load of nonlinear simply supported RC slabs by a patch with respect to reinforcement ratio, thickness and angles of CFRP sheets.
Estimation of Saturation Depth by Reflecting Water-redistribution Phenomena at a Natural Slope
Kim, Woong-Ku ; Chang, Pyoung-Wuck ; Cha, Kyung-Seob ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 71~79
DOI : 10.5389/KSAE.2006.48.1.071
In Korea, most landslides occurred during the rainy season and had a shallow failure plane parallel to the slope. For these types of rainfall-induced failures, the most important factor triggering slope unstability is decrease in the matric suction of unsaturated soils with increasing saturation depth by rainfall infiltration. The saturation depth was readily estimated using modified Green-Ampt model proposed by Chu et al. (Chu Model) at present. But Chu Model involves some problems for application, because water-redistribution phenomena were not effected. So the modified Chu Model (MCGAM) which reflect water redistribution phono mens was developed. The results showed that the MCGAM had a better agreement with measured volumetric water contents than existing Chu Model.
Simulation of Effects of the Size of Embedded Rock Layer under Earth Fill on Seepage Problems of Sea-dike
Lee Haeng Woo ; Chang Pyoung Wuck ; Song Chang Seob ; Won Jeong Yun ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 81~88
DOI : 10.5389/KSAE.2006.48.1.081
Numerical analyses were carried out for studying on seepage problems due to seawater intrusion through the embedded rock layers of the sea-dike. A seepage analysis model, SAMTLE was developed fur two-layer embankment system. The analyses by SAMTLE showed that the size of embedded rock layer had a significant effect on the seepage problems of sea-dike. If the embedded rock layer is longer and thicker, the seepage problems become more serious to water head, seepage rate and safety factor of piping in embankment. On the other hand, if the width of embedded rock layer is equivalent to the sea-dike's bottom width, the water head becomes lower and seepage rate and safety factor of piping are dramatically increasing. This makes another seepage problems such that the fresh water becomes saltier and higher seepage rates result in internal erosion of sea-dike.
Water Quality and Correlation Analysis Between Water Quality Parameters in the Hwaong Watershed
Jung Kwang-Wook ; Yoon Chun-Gyeong ; Jang Jae-Ho ; Jeon Ji-Hong ;
Journal of The Korean Society of Agricultural Engineers, volume 48, issue 1, 2006, Pages 91~102
DOI : 10.5389/KSAE.2006.48.1.091
Most projects of tideland reclamation with dike construction produce estuarine reservoirs, which may result in water quality problems due to blocking of natural flow of stream water to the sea. External loadings to the reservoirs through tributaries are major concerns in a concerned water quality management. The water quality of a reservoir is greatly influenced by watershed drainage, and accurate estimation of pollutant is indispensable for in the reservoir management. Concentrations of the microorganisms in stream water and conventional parameters were monitored in the 13 water quality monitoring sites located in a rural watershed of Hwaong estuarine reservoir. The indicator of microorganisms showed strong correlation between them, and regression equations with
may be used fur estimating one from other microorganisms. The relationships between water quality parameters obtained in this study may be used to infer one unknown pollutant concentrations from the measured pollutant loadings. This methodology could be applied to other areas where the watershed characteristics are not significantly different from the study area. High concentrations of nitrogen was observed in water quality monitoring sites affected by urban land uses and numbers of livestock in wet day as well as dry day, due to the influent of diffuse sources.