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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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Journal DOI :
The Korean Society of Agricultural Engineers
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Volume & Issues
Volume 46, Issue 7 - Dec 2004
Volume 46, Issue 4 - Jul 2004
Volume 46, Issue 3 - May 2004
Volume 46, Issue 6 - Jan 2004
Volume 46, Issue 5 - Jan 2004
Volume 46, Issue 2 - Jan 2004
Volume 46, Issue 1 - Jan 2004
Selecting the target year
Hydraulic Model Experiment for Field Application of Iceharbor-type Precast Fishway
Kim, Jae-Ok ; Park, Sang-Hyun ; Cho, Jae-Won ; Hwang , Jong-Seo ; Jo , Guk-Hyun ; Joh , Seong-Ju ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 3~14
DOI : 10.5389/KSAE.2004.46.2.003
This study was conducted to assess the possibility of the field application of the iceharbor-type precast fishway. When overflow depth of weir is 4.0 cm in model fishway, upper part velocities appear appropriate for upstream migration of fish and the lowest overflow wall (right line) in lower part has shown velocity distribution more or less inadequate for upstream migration. Except that right line, left and middle line revealed that velocities are appropriate for upstream migration of fish. Therefore, we concluded that this fishway owing to be not broad growth width of overflow velocities according to increasing discharges can correspond to variation of water level. Also We consider that various velocities in fishway were effective, because slow velocity line can guide flow for upstream migration. For low flow, the arrangement of different crest level or each overflow part (higher left, middle and lower right, or lower left, middle and higher right) was more effactive than unform crert level. Hole plays an important role as migration pass during drought and flood flow. Therefore, We concluded that this fishway can cope with water depth variation by various overflow wall height change and raise the field applicability with better performance hydraulically and structurally.
Flood Effects Analysis of Reservoir Basin through the Linkage of HEC-HMS and HEC-RAS Models
Lee, Weon-Hee ; Kim , Sun-Joo ; Kim , Phil-Shik ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 15~25
DOI : 10.5389/KSAE.2004.46.2.015
For the effective operation of irrigation reservoirs, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. In this study, the flood effective analysis system was developed through the integration of long-term water budget analysis model, GIS-based HEC-HMS model and HEC-RAS model. The system structure consists of long-term water budget model using modified TANK theory, flood runoff and flood effects analysis model using HEC-GeoHMS, HEC-HMS and HEC-RAS models. The flood effects analysis system simulated the flood runoff from the upstream, downstream flood and long-term runoff of the watershed using the observed data collected from 1998 to 2002 of Seongju dam. The simulated results were reasonably good compared with the observed data. The optimal management method of the reservoir during the whole season is suggested in this study, and the flood analysis system can be a useful tool to evaluate a reservoir operation quantitatively for the mitigation of flood damages of reservoir basin.
Development of An Areal Elderly Migration Model for Demand Estimation of Rural Retirement Community
Jung, Nam-Su ; Lee , Jeong-Jae ; Kim , Han-Joong ; Yoon , Seong-Su ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 29~37
DOI : 10.5389/KSAE.2004.46.2.029
An areal elderly migration model (AEMM) was developed to assess the demand of rural development projects targeted towards elderly people. The AEMM was developed with adaptation of the gravity model to represent spatial interaction regarding amenities. Areal characteristics were classified for estimating the amenities from the perspective of net migration. From 1990 to 2000, data were acquired from USCB, PASDA, PAHEALTH, PADCNR, PFBC, and NCDC in 67 Pennsylvania counties for analysis and application. The results revealed that elderly migration can be explained not only by areal characteristics but also by spatial interaction considering the population, distances, and amenities of surrounding areas.
Model Tests Study on Flow-induced Vibrationof Tainter Gate in Estuary Sulices(Ⅱ)- Flow from the Gate Inside to the Gate Outside -
Lee , Seong-Haeng ; Woo , Sang-Ik ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 41~47
DOI : 10.5389/KSAE.2004.46.2.041
A model test is carried out to investigate flow-induced vibration of a Tainter gate in estuary sulices. The gate model scaled with the ratio of 1:25 is made of acryl panel dimensioned 0.66 m in width, 0.5 m in height in the concrete test flume. Firstly, natural frequencies of the model gate are measured and the results are compared with the numerical results in order to verify the model. In the flow from the gate inside to the gate outside, the amplitudes of the vibration are measured under the different gate opening and downstream water level conditions. Also revised gate models with 20 mm bottom width are tested under the different gate openings and water levels. The results are analyzed to study the characteristics of the Tainter gate vibration in the sea ward flow. These test results are assessed in comparison with the results in the lake ward flow, as a result, presents the dynamic characteristics of the Tainter gate and a basic data for the guide manuals of gate management.
Effect of Flat and Elongated Particles in Coarse Aggregates on Properties of Concrete
Won , Jong-Pil ; Cho, Yong-Chin ; Park , Kwang-Su ; Shin , Su-Gyun ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 49~57
DOI : 10.5389/KSAE.2004.46.2.049
Generally, the properties of aggregate greatly affect the physical and mechanical properties of concrete. Flat and elongated particles in coarse aggregates, for some construction uses, may interfere with consolidation and be difficult to place. In this study, an experiment to evaluate properties of flat and elongated particles as coarse aggregate in concrete was conducted. The experiments include slump test, air content test and compressive strength test. The test result of slump and change of slump was rapidly decreased by percentage of flat and elongated particles. But it had not a trend by increasing percentage of flat and elongated particles. Compressive strength of hardened concrete does not make any differences in comparison.
Freezing and Thawing Properties of High Strength Concrete Using Recycled Coarse Aggregate
Sung , Chan-Yong ; Im , Sang-Hyuk ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 59~66
DOI : 10.5389/KSAE.2004.46.2.059
This study was performed to evaluate the freezing and thawing properties of the high strength concrete using recycled coarse aggregate. The recycled coarse aggregate replaced natural crushed aggregate by 0%, 25%, 50%, 75% and 100%. The compressive strength of the concrete using recycled coarse aggregate showed more than 300 kgf/
at the curing age 28 days. The mass loss ratio by freezing and thawing was less than 1% at all mix type. The relative dynamic modulus of elasticity was decreased with increasing the freezing and thawing cycles. Also, the durability factor by the freezing and thawing was decreased with increasing the content of recycled coarse aggregate. But, the recycled concrete except 100% recycled coarse aggregate showed 60 or more durability factor in the freezing and thawing 300 cycles. Accordingly, these recycled coarse aggregate can be used for high strength concrete.
Dynamic Behavior of Plane Parabolic Arches with Initial Deflections
Cho , Jin-Goo ; Park, Keun-Soo ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 67~75
DOI : 10.5389/KSAE.2004.46.2.067
This study aims to investigate the dynamic behaviour of a parabolic arch with initial deflection by using the elasto-plastic finite element model where the von-Mises yield criteria have been adopted. The initial deflection of arch was assumed by the high order polynomial of
) and the sinusoidal profile of
x/L). Several numerical examples were tested considering symmetric initial deflection modes when the maximum initial deflection of an arch is fixed as L/500, L/1000, L/2000 or L/5000. The effects of polynomials order on the dynamic behavior of arch were not conspicuous. The most unfavorite dynamic response occurs when the maximum initial deflection varies from L/1000 to L/4000 if the initial deflection mode is represented by high order polynomials.
Reasonable Optimum Design of Prestressed Concrete Structures
Kim, Jong-Ok ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 77~89
DOI : 10.5389/KSAE.2004.46.2.077
This study was carried out to find out the reasonable optimum design method for the design of prestressed concrete structures. The optimum design problems were formulated and computer programs to solve these problems were developed. To test the reliablity, efficiency, possibility of application and reasonablity of optimum design problems and computer programs, both continuous optimization method and mixed-discrete optimization method were applied to the design of prestressed concrete composite girder and application results were discussed. It is proved that mixed-discrete optimization method is more reliable, efficient and reasonable than continuous optimization method for the optimum design of prestressed concrete structures.
Stability Analysis of the Light Weight Earth-Retaining Structure in the Trench Excavation
Seo , Sung-Tag ; Heo , Chang-Han ; Kim , Hee-Duck ; Jee , Hong-Kee ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 93~103
DOI : 10.5389/KSAE.2004.46.2.093
In trench excavation, essential factor of earth-retaining temporary work structure should be easy taking to pieces and movement, and dead weight must be less. This paper studies about the light weight material and application as earth-retaining structure to prevent the slope failure of sand soil ground caused by the variation of groundwater level in trench excavation. That is, light weight earth-retaining structural is proposed and a simulation with FEM on application of proposed structural in sandy soil is presented. The results are summarized as follows; (1) The study proposed FRP H-shaped pannel for the light weight member, and also presented estimation method about stability. (2) Mechanical property (bending moment, shear force, axial force, displacement) were changed according to groundwater level, but these values had been within enough safety rate and allowable stress. Therefore, proposed light weight pannel with FRP is available for bracing structure in trench excavation.
Evaluation of NPS Pollutant Loads from Clayey Loam Fields
Choi, Joong-Dae ; Kwun, Soon-Kuk ; Kwon, Gi-Seok ;
Journal of The Korean Society of Agricultural Engineers, volume 46, issue 2, 2004, Pages 107~114
DOI : 10.5389/KSAE.2004.46.2.107
NPS pollutant loads from sandy clayey and clayey loam runoff plots were measured. Runoff plots were 2
10 m in size and 8~10% in slope and paddy area was 4,620
. Soybean, corn, tobacco and control (natural weed) were cultured. Precipitation during the growing season of June to October, 2002 was 869.5 mm. Runoff and water quality were measured more than 10 times during the measurements depending on the growing stage. Pollutants loads were estimated by using respective concentration and runoff volume. Runoff occurred when daily rainfall exceeded about 30 mm. The largest runoff was observed from the paddy but pollutant loads were larger from upland crops than those from paddy. SS loads from paddy and upland were 1.4 ton/ha/yr and 3.1~4.3 ton/ha/yr, respectively. COD loads 30 kg/ha/yr and 66~90 kg/ha/yr, T-N loads 13 kg/ha/yr and 14~23 kg/ha/yr, T-P loads 1 kg/ha/yr와 4 kg/ha/yr, nitrate nitrogen loads 1 kg/ha/yr and 4~8 kg/ha/yr, and phosphate phosphorus loads 0 kg/ha/yr and 4~6 kg/ha/yr, respectively. It was concluded that NPS pollutant loads from upland crop culture have greater impact on the quality of the receiving water body than those from paddy culture.