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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 16, Issue 3_6 - Nov 1996
Volume 16, Issue 2_6 - Nov 1996
Volume 16, Issue 1_6 - Nov 1996
Volume 16, Issue 3_5 - Sep 1996
Volume 16, Issue 2_5 - Sep 1996
Volume 16, Issue 1_5 - Sep 1996
Volume 16, Issue 3_4 - Jul 1996
Volume 16, Issue 2_4 - Jul 1996
Volume 16, Issue 1_4 - Jul 1996
Volume 16, Issue 3_3 - May 1996
Volume 16, Issue 2_3 - May 1996
Volume 16, Issue 1_3 - May 1996
Volume 16, Issue 3_2 - Mar 1996
Volume 16, Issue 2_2 - Mar 1996
Volume 16, Issue 1_2 - Mar 1996
Volume 16, Issue 3_1 - Jan 1996
Volume 16, Issue 2_1 - Jan 1996
Volume 16, Issue 1_1 - Jan 1996
Selecting the target year
Analyses of Riprap Design Formulae for Protecting Local Scour Around Bridge Piers
Yoon, Tae-Hoon ; Yoon, Sung-Bum ; Yoon, Kwang-Seok ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 411~411
Extensive experiments are carried out to evaluate the accuracy and applicability of existing riprap design equations for the protection of local scour around a circular bridge pier. The evaluations of design formulas are made through the comparisons of calculated and observed diameters of riprap stone. Safety factors of the formulas are also presented. Most of the design equations are based on the approach velocity of streamflow, and factors such as pier width and flow depth are ignored partially or completely. Inadequate inclusion of such factors are found in some equations. Most of the design equations are found to overestimate or underestimate the size of the riprap based on the experimental data. The equations proposed by Richardson et al. (1993) and Parola (1993) give relatively adequate size of the ripraps. A need for improved design formula which takes into account of both pier width and water depth is raised.
Runoff Effect and Flood Reduction Counterplan due to Urbanization -Application to Bupyung(2) Drainage Basin-
Seo, Kyu-Woo ; Heo, Jun-Haeng ; Cho, Won-Cheol ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 421~421
The unbanization rate of Bupyung (2) drainage basin (460 ha) is about 70%. In near future, this rate will be changed to 80% and 90% because of areal development plan. The purposes of this study are to analyze the runoff effect of this area due to the urbanization of downstream of Dongsucheon by using ILLUDAS model and to make a counterplan for flood reduction. As a result, the average increasing rates of peak discharge for 5, 10, and 20 years return periods were 4.4% and 8.8% for the corresponding future urbanization rates. For flood reduction, Dongsucheon improvement plan was proposed to convey the project flood of 20 years return period peak discharge (68.3 cms) considering the backwater effect of downstream. Also, a detention reservoir of
and 10 units of 460 Hp pump having
pumping capacity were proposed at downstream of Dongsucheon.
The Stochastic Monthly Runoff Generation Model by Bayesian Approaches -Normal and Log-Normal Process-
Yoon, Hae-Sik ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 433~433
The objective of this study was to determine the stochastic monthly runoff generation model by Bayesian approaches. Bayesian approaches have been applied to the hydrologic time series models such as independent normal process and independent log-normal process. In this study, the analysis was carried out with data from Nakdong, Waegwan and Hyeonpung stations in the Nakdong river basin which have more than 30 years historical records. According to the comparison and investigation of the statistics of the generation results by Bayesian models, the statistics of independent log-normal process approached well to those of historical and classical model. According to the estimation and comparison of the probable monthly runoffs by the frequency analysis, those of independent log-normal process showed well comparatively Bayesian concept which is the reduction of the uncertainty than those of Independent Normal Process.
A Topological View of Chaos: (I) Application to a Daily Streamflow Analysis
Kim, Hung-Soo ; Yoon, Yong-Nam ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 445~445
While the metric approaches such as correlation dimension and the largest Lyapunov exponent have been mostly used to distinguish chaos from stochastic system, and they are becoming the standard rules for testing chaotic behavior of a scalar time series, some studies have recently developed topological techniques for testing deterministic chaos. Relatively, topological techniques require small data set and easy implementation. This paper applies one of topological methodologies called the close returns test which has successful applications in physics and in the economic data sets to a daily streamflow time series for testing the deterministic chaos. The result by a topological technique is compared with those of metric approaches. In our analysis, a daily streamflow based on the metric approaches represents its chaotic behavior, but the deterministic chaos is rejected from a topopogical technique. The close returns test shows the periodic pattern of a daily streamflow and it may be considered that the periodic stochastic models are more appropriate for a daily streamflow applied in this study.
A Topological View of Chaos: (II) Independence and Noise Cancellation
Kim, Hung-Soo ; Yoon, Yong-Nam ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 453~453
Since autocorrelation function cannot distinguish chaotic system from random noise, we apply the power spectrum for some time series to see if the power spectrum can discern between chaotic system and random process. In our experiment. the chaotic system and the random process shows the same structure as broad band spectra. Therefore, the power spectrum cannot also distinguish chaotic time series from random signal. In step two, the histogram of close returns plot is used for testing independence of a daily streamflow at Cache La Poudre river. The result shows its periodicity as proved by close returns plot (Kim and Yoon, this issue). This also exhibits the daily streamflow should be interpreted by some periodic stochastic models. In final step, we show the noise of time series can be reduced by using the simple moving average method on the close returns plot. An example of a periodic time series is explained for the noise reduction and the result represents that the moving average technique is useful for the noise cancellation.
Three-dimensional Model of Reservoir Sedimentation Processes
Yoon, Tae-Hoon ; Kim, Chang-Wan ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 461~461
For the estimation of bed evolution in Paldang reservoir and its consequent reduction of storage capacity since the completion of Paldang dam, three dimensional sediment transport model coupled with the quasi-three dimensional hydrodynamic model was developed. The quasi-three dimensional hydrodynamic model. which is derived by integration of vertical logarithmic velocity distribution modified by adding the wake function including the effect of bottom topography and bottom roughness, is to compute 3-D velocity distribution from 2-dimensional depth integrated velocities by 2-D depth integrated circulation model. The general pattern of the bed evolution simulated is very close to the measured sixteen years after the completion of the dam. The geomorphological change in Paldang reservoir resulted in net sediment deposition. Overall accuracy of the simulated results indicate that the model can be used as a tool of evaluation for fluvial bed evolution in a shallow water body.
Prediction of Alongshore Sediment Transport Rate due to the Incident Wave Conditions
Lee, Cheol-Eung ; Lee, Kil-Seong ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 469~469
The total immersed weight sediment transport rate based on Bailard's energetic model is modified to include the turbulence effect. Using the time-varying total velocity and the Ostendorf and Madsen's current model, we can directly predict the transport rate distribution across the surf-zone. Also. the total immersed weight alongshore transport rate is linked to the volumetric alongshore sediment transport rate equation by integrating spatially over the on-offshore direction. For the typical surf-zone condition, the sediment transport is almost occurred inside the narrow surf-zone and the position of the maximum transport rate are located at more seaward than that of the maximum alongshore current. It is found that the shoreline diffusivity is a function of the incident wave and current conditions, the beach slope, and the sediment size. However when the breaker angle is constant and the relative velocity is small, the shoreline diffusivity can be treated as a constant. The volumetric sediment transport rate depends closely on the shoreline diffusivity, the breaking wave height and the breaker angle. Under the condition of the large relative velocity, the sediment near the surf-zone is almost transported by the suspended load.
Determination of Optimum Operational Parameters using Factorial Design in Photocatalytic Oxidative Reactors
Choung, Youn-Kyoo ; Ko, Kwang-Baik ; Cheon, Seung-Yul ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 483~483
The major objective of this study is to delineate optimum operational parameters using factorial design for phenol degradation in photocatalytic oxidative reactors. Factorial design is widely used in experiments involving several factors where it is necessary to study the joint effects of the factors on a response. The effects of initial concentration of phenol, UV light intensity and, surface area of catalyst on phenol degradation were investigated. Only two levels were considered in this study so that the experiment was a
factorial design with three replicates. The experimental results show that an increase in initial concentration of phenol from 5 to 50 mg/L, UV light intensity from
, and surface area of catalyst from
enhanced the phenol degradation rate by an average of 1.86, 1.79, and 2.10 mg/L hr respectively. Interaction effects do not appear to be as large on phenol degradation rate as the main effects except for initial concentration of phenol and surface area of catalyst.
Use of Packed Flotation Column for Volume Reduction of Soil Contaminated with Oil and Heavy Metal
Cho, Jung-Moo ; Park, Kyoo-Hong ; Kim, Sung-Soon ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 493~493
Flotation is a relatively effective and economic method for selectively separating fine particle in liquid. This study was performed to apply the flotation process to the pretreatment of the contaminated sediments in river or estuaries for the purpose of reduction of the volume to be treated. Using PFCM(Packed Flotation Column Model), sensitivity analysis was conducted to examine the effect of several operating conditions on the performance of flotation separation, e.g., recovery and removal efficiency of contaminants, grade of uncontaminated soil. The packed flotation column was designed, set up, and operated to examine the effect of the selected variables, air flowrate and wash water flowrate, on the flotation performance. Both the recovery and grade were found to be sensitive to air flowrate and wash water flowrate. both in sensitivity analysis and in experiment. Although all the other operating variables than air flowrate and washwater flowrate were not considered experimentally, utilization of the sensitivity test results may be helpful to the design and operation of the actual flotation experimental tests.
A Kinetics Study on Phosphorus Removal using Slag
Lee, Seung-Hwan ; Ahn, Kyu-Hong ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 505~505
Kinetic studies on phosphorus (P as orthophosphate) removal onto converter and furnace slag (BHP steel industry by-products, Australia) media revealed that P removal is a slow process. More than 90% of the P was adsorbed within 12 and 60 hours for the converter and furnace slag respectively, The converter slag adsorved the P more than the furnace slag (4 times for initial concentration of 40 mg/l as P). P removal was described bolter by an equation using Langmuir isotherm constants than the one using Freundlich isotherm constants. The Kinetic studies of P removal were satisfactorily explained by a static, physical, non-equilibrium sorption model (SPNSM). Distribution of the film transfer constants for the converter slag was more scattered than the furnace slag.
Phosphorus Removal in Soil under Static System: Effect of Agitation
Lee, Seung-Hwan ; Ahn, Kyu-Hong ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 513~513
Estimation of removal rate capacity for P in soils and the adsorbents-water environment are important factors to consider in the evaluation of the P removal to design an efficient land treatment facility. In this study, detailed batch (static) sorption experiments for P removal onto a sandy loam soil from North Sydney, Australia, were conducted to study the effect of agitation. The batch experimental results show that P sorption is significantly affected by agitation. It took almost 10 times to adsorb more than 90% of the P in the system without agitation. The kinetics of P sorption gives better predictions in the system without agitation by a static, physical, non-equilibrium sorption model using Freundlich isotherm constants. The effect of agitation was quantified by using the distribution and fluctuation of film transfer constant.
Study on the Modeling of Anoxifier Process for Wastewater Treatment
Chun, Yang-Kun ; Choi, Yong-Su ; Choung, Youn-Kyoo ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_5, 1996, Pages 521~521
Anoxifier Process was invented to remove organic compound as well as nitrogen. It was consisted of two parts; one part was aeration basin, the other was anoxifier which com bined anoxic basin and clarifier. Inclined plate divided anoxifier into clarifier and anoxic zone clearly, and it separated clear-layer from mixed liquid efficiently. Experimental and kinetic studies were carried out using this process. The results showed high removal rates for organic compound, nitrogen and suspended solid, in addition, running cost and establishing area could be saved. Therefore it was recognized that Anoxifier Process was recommendable for small wastewater treatment for organic and nitrogen removal in rural areas close to the water resources.