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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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Korean Society of Civil Engeneers
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Volume & Issues
Volume 26, Issue 6D - Nov 2006
Volume 26, Issue 6C - Nov 2006
Volume 26, Issue 6B - Nov 2006
Volume 26, Issue 6A - Nov 2006
Volume 26, Issue 5D - Sep 2006
Volume 26, Issue 5C - Sep 2006
Volume 26, Issue 5B - Sep 2006
Volume 26, Issue 5A - Sep 2006
Volume 26, Issue 4D - Jul 2006
Volume 26, Issue 4C - Jul 2006
Volume 26, Issue 4B - Jul 2006
Volume 26, Issue 4A - Jul 2006
Volume 26, Issue 3D - May 2006
Volume 26, Issue 3C - May 2006
Volume 26, Issue 3B - May 2006
Volume 26, Issue 3A - May 2006
Volume 26, Issue 2D - Mar 2006
Volume 26, Issue 2C - Mar 2006
Volume 26, Issue 2B - Mar 2006
Volume 26, Issue 2A - Mar 2006
Volume 26, Issue 1D - Jan 2006
Volume 26, Issue 1C - Jan 2006
Volume 26, Issue 1B - Jan 2006
Volume 26, Issue 1A - Jan 2006
Selecting the target year
3-D Numerical Simulation of Open-Channel Flows over Smooth-Rough Bed Strips
Choi, Sung-Uk ; Park, Moonhyeong ; Kang, Hyeongsik ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 573~581
This paper presents a turbulence modeling of the open-channel flows over smooth-rough bed strips. A Reynolds stress model is used for the turbulence closure. The simulated mean flow and turbulence structures are compared with the previously reported experimental data. Comparisons reveal that the developed Reynolds stress model successfully predicts the mean flow and turbulence structures of open-channel flows over smooth-rough bed strips. The computed flow vectors show cellular secondary currents, of which the upflow occurs over the smooth bed strip and the downflow over the rough bed strip. It is found that the cellular secondary currents affect the mean flow and turbulence structure. A budget analysis of the streamwise vorticity equation is also carried out to investigate the mechanism by which the secondary currents are generated.
Analysis of Pan Evaporation Data from 1973 to 2004 in South Korea
Kim, Gwangseob ; Yim, TaeKyung ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 583~596
Evaporation is an essential parameter in Global water-energy cycle and the variability of evaporation affects water resources planning and managements. In this study, the temporal variability of pan evaporation data was analyzed and trend analysis of the data using Mann-Kendall test. The relationships among evaporation and rainfall, air temperature, humidity, cloudness were analyzed. Even though the longterm trends of air temperature and rainfall increases, that of evaporation except Jinju and Yeosoo results decreases as worldwide observations. Results demonstrate that decrease of pan evaporation represents increase of terrestrial evaporation as Brutsaert and Parlange(1998)'s analysis.
Rainfall Forecasting Using Satellite Information and Integrated Flood Runoff and Inundation Analysis (I): Theory and Development of Model
Choi, Hyuk Joon ; Han, Kun Yeun ; Kim, Gwangseob ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 597~603
The purpose of this study is to improve the short term rainfall forecast skill using neural network model that can deal with the non-linear behavior between satellite data and ground observation, and minimize the flood damage. To overcome the geographical limitation of Korean peninsula and get the long forecast lead time of 3 to 6 hour, the developed rainfall forecast model took satellite imageries and wide range AWS data. The architecture of neural network model is a multi-layer neural network which consists of one input layer, one hidden layer, and one output layer. Neural network is trained using a momentum back propagation algorithm. Flood was estimated using rainfall forecasts. We developed a dynamic flood inundation model which is associated with 1-dimensional flood routing model. Therefore the model can forecast flood aspect in a protected lowland by levee failure of river. In the case of multiple levee breaks at main stream and tributaries, the developed flood inundation model can estimate flood level in a river and inundation level and area in a protected lowland simultaneously.
Rainfall Forecasting Using Satellite Information and Integrated Flood Runoff and Inundation Analysis (II): Application and Analysis
Choi, Hyuk Joon ; Han, Kun Yeun ; Kim, Gwangseob ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 605~612
In this study(II), The developed rainfall forecast model was applied to the NakDong River Basin for the heavy rainfall on 6th to 16th of August in 2002. The results demonstrated that the rainfall forecasts of 3 hours lead time showed good agreement with observed data. The inundation aspect of simulation depends on actual levee failure in the same basin. Rainfall forecasts were used for flood amount computation in the target watershed. Also the flood amount in the target watershed was used on boundary condition for flood inundation simulation in a protected lowland and a river. The results of simulation are consistent with actuality inundation traces and flood level data of the target watershed. This study provides practical applicability of satellite data in rainfall forecast of extreme events such as heavy rainfall or typhoon. Also this study presented an advanced integrated model of rainfall, runoff, and inundation analysis which can be applicable for flood disaster prevention and mitigation.
Evaluation of Accuracy of the Physics Based Distributed Hydrologic Model Using Vflo
Hong, Jun Bum ; Kim, Byung Sik ; Yoon, Seok Young ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 613~622
In this study, a fully distributed physical-based rainfall-runoff model called Vflo
is applied to Junglang-cheon basin for simulating runoff. Geo-spatial data are used to parameterize the model to account for the characteristics of soils, landuse/cover, and topograph. 300m resolution DEM is used to compute slope and drainage network connectivity. Spatially distributed rainfall data is interpolated by ordinary kriging method. In this study, hydrograph from HEC-HMS and Vflo
without/with calibration of parameters was compared to evaluate the accuracy of rainfall-runoff model From the results, a fully distributed physical-based rainfall-runoff model reproduce the peak time and shape of hydrograph much better than HEC-HMS.
Development of Axially Periodic Transient Storage Zone Model for the Solute Mixing in Natural Streams and Rivers with Various Bottom Boundaries
Cheeong, Tae Sung ; Seo, Il Won ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 623~631
A new model, the periodic transient storage zone model, is developed to describe solute transport mixing in natural streams and rivers with various bottom boundaries. To assess the effects of storage zones structure on transient storage exchange, we analyze data from salt and dye injection experiments in a recirculating laboratory flume with four spatially periodic pool-riffle sequences characteristic of natural river systems under low flow conditions. Dye injections show that solute transport mixing controlled by surface shapes of both the bed and the side in channels. As no existing transient storage model could represent these effects, we developed a new axially periodic transient storage zone model that better represent the effects of channel characteristics in natural river systems. The new model is also fitted to data from salt tracer injection experiments in four reaches of the upper Sabin River, Texas, USA. The proposed model is in good agreement with the field experimental data.
Validity of Empirical Formulas for Estimation of Reflection Coefficient of Waves Due to Perforated Wall
Yoon, Sung Bum ; Lee, Jong In ; Han, Sang Cheol ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 633~639
The validity of the existing formulas for the estimation of reflection coefficient of waves due to perforated wall is investigated using the result of hydraulic experiments conducted with perforated walls of various thickness. The result shows that, when the wall is thick, the energy loss coefficient is reduced to 62% of the value evaluated using the existing formula for sharp-crested orifice. The result also shows that the length of inertia resistance increases linearly as the thickness of the wall increases. The width of chamber to achieve the minimum reflection of waves decreases as the length of inertia resistance increases. Thus, the result found in the present study can be usful for the design of perforated wall.
Comparative Evaluation of Behavior Analysis of Rectangular Jet and Two-dimensional Jet
Kwon, Seok Jae ; Cho, Hong Yeon ; Seo, Il Won ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 641~649
The behavior of a three-dimensional pure rectangular water jet with aspect ratio of 10 was experimentally investigated based on the results of the mean velocity field obtained by PIV. The saddle back distribution was observed in the lateral distribution along the major axis. The theoretical centerline velocity equation derived from the point source concept using the spreading rate for the axisymmetric jet was in good agreement with the measured centerline velocity and gave the division of the potential core region, two-dimensional region, and axisymmetric region. The range of the two-dimensional region divided by the criterion of the theoretical centerline velocity decay for the aspect ratio of 10 was observed to be smaller than that of the transition region. The applicability of the two-dimensional model to the behavior of the rectangular jet with low aspect ratio or the wastewater discharged from a multiport diffuser in the deep water of real ocean may result in significant error in the transition and axisymmetric regions after the two-dimensional region. In the two-dimensional region, the Gaussian constant tended to be conserved, and the spreading rate slightly decreased at the end of the two-dimensional region. The normalized turbulent intensity along the centerline of the jet initially abruptly increased and showed relatively higher intensity for higher Reynolds number.
Estimation of Harbor Operating Ratio Based on Moored Ship Motion
Kwak, Moonsu ; Chung, Jaewan ; Ahn, Sungphil ; Pyun, Chongkun ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 651~660
Although a harbor may be constructed with calmness in harbor in mind, which satisfies the design standard, it is frequently reported that the motion of moored ships disrupt the cargo handling. This is because of current design standard, which only deals with the wave height in the decision making process of cargo handling, and, now, a new kind of estimation method of operating ratio for calmness based on the motion of moored ship is in need. In this research, a computational method that analyses the harbor operation rate in harbor was put forward by considering the relation of allowable quantity of motion for cargo handling and the computation of the motion of moored ship at wharf by using moored ship motion analysis model. Here, a new estimetion method was applied at Onsan harbor, and it was compared with the current estimation method, and, then, the difference between the two methods was showed. The harbor operating ratio gained by a new method was dropped by 2~11% at ENE and NE directions when it was compared with the operating ratio based on the current design standard. However, when a harbor structure layout is to be designed, a harbor operating ratio test according to the wave height and a harbor operation rate test, which considers the motion of moored ship, are to be run side by side at a harbor designing process.
Dewatering of Sewage Sludge by Electrokinetics
Kim, Ji Tae ; Won, Se Yeon ; Cho, Won Cheol ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 661~667
In this study, an experiment of sewage sludge dewatering is carried by using electrokinetic method, and the electrokinetic dewatering efficiency of digested sludge is analyzed. Digested sludge without coagulants is selected and gravitational and pressing dewatering methods are applied in combination with electro-osmotic and electro-osmotic pulse technology. After the test of digested sludge, dewatering test of thickened sludge is carried to evaluate the electrokinetic dewatering feasibility of thickened sludge. Under the condition of constantly applied voltage, however, electrical resistance increases with decreasing of water content so that dewatering rate decreases with time. To reduce such a hindrance caused by constantly applied voltage, electro-osmotic pulse technology which is considered to reduce the difference of water content with height, is applied. For the application of electro-osmotic pulse, the dewatered flow rate and the dewatered volume became more increasing from the middle of the dewatering process than that of continuous voltage. Through the test of thickened sludge, electro-osmotic dewatering combined with gravitational and expression also showed high dewatering rate, which proved the possibility of using electrokinetic dewatering.
Solids and Nitrogen Removal in the Sludge Digestion using a Sequencing Batch Reactor
Kim, Sung Hong ; Lee, Yoon Heui ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 669~675
Intermittent aerobic digestion experiments using a sequencing batch reactor (SBR) were carried out in this study. Aeration ratio was found to be an important operation factor for the reduction of solids and nitrogen. As the sludge digested, organic nitrogen was released from the solids and oxidized to nitrate nitrogen. Biological denitrification was also significant and the denitrification rate was limited by aeration ratio. Under the condition of 0.25-0.75 of aeration ratio, acclimation of ammonia nitrogen was not observed and pH were preserved near neutral in the intermittent aerobic digestion. As the aeration ratio increased, solids reduction was increased whereas dissolved nitrogen removal was decreased. Based on the experiments, 17-2% of VSS reduction and over 80% of dissolved nitrogen removal were practicable by intermittent aerobic digestion using a SBR when the MSRT were designed 8-32 days and aeration ratio was operated about 0.25-0.75.
Effect of Metal Ion on the Bentonite Modified with Cationic Surfactant
Kim, Soo-Hong ; Park, Jae-Woo ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 677~682
Dodecyldimethylethylammonium (DDDEA), a cationic surfactant, and aluminum metal ions were used with bentonite to synthesize to synthesize an improved organo bentonite. Among three different synthesis procedure for organo bentonites, aluminium-pillared bentonite showed the highest DDDEA sorption, which indicated that aluminium-pillared organo bentonite would exhibit the highest sorption capacity for organic contaminants. Aluminium pillared organo bentonite also showed a high sorption capability for phosphorus, while it did not exhibit strong sorption for nitrate. In the meantime, more desorption was observed with aluminium-pillared organo bentonite than ordinary organo bentonites.
Effects of Aeration on Bio-hydrogen (Bio-H
) Production in the Anaerobic Digestion
Lee, Myoung Joo ; Jang, Hyun Sup ; Hwang, Sun Jin ; Jeong, Yeon Koo ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 683~687
This research investigated the effect of aeration pretreatment for anaerobic seed sludge on hydrogen production. Aeration time for anaerobic sludge was maintained at 0, 1, 3, 6, 12, and 24 hours in batch tests. Two continuous anaerobic reactors (aerated and non-aerated) were also operated. All experiments were conducted at
using mineral salts-glucose (20 g/l) medium. Methane production decreased with the increase in aeration time. Aeration for 6 hours was determined as an optimum from the amount of hydrogen produced. Hydrogen was steadily produced in the continuous reactor seeded with aerated sludge while no methane production was observed. However, small amount of hydrogen was produced in the non-aerated reactor for short period of time from the start even though short HRT (2 days) and low pH (5.5) were maintained.
Biodegradation of VOC Mixtures using a Bioactive Foam Reactor I: Reactor Performance
Shin, Shoung Kyu ; Jang, Hyun Sup ; Hwang, Sun Jin ; Song, Ji Hyeon ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 689~694
The system performance of a bioactive foam reactor (BFR), that consists of a foam column using a surfactant and a biodegradation basin containing suspended bacteria, was investigated for the treatment of gaseous toluene or a mixture of four volatile organic compounds (VOCs, benzene, toluene, p-xylene, and styrene). Overall, the BFR achieved stable VOC removal efficiencies, indicating that it can be used as a potential alternative over conventional packed-bed biofilters. Furthermore, a dynamic loading test showed that relatively constant removal was maintained at the elevated loading due to a high mass transfer rate in the foam column. However, as the inlet concentration of VOCs increased, a portion of the VOCs mass-transferred to the liquid phase was stripped out from the biodegradation basin, resulting in a decrease in the overall removal efficiency. In the BFR, the removal efficiency of the individual VOC was mainly determined depending on the biodegradation rate (styrene > toluene > benzene > p-xylene), rather than the mass transfer rate. Consequently, increases in the microbial activity and the volume of the basin could improve the overall performance of the BFR system. Further investigation on microbial activity and community dynamics is required for the BFR when subjected to high loadings of VOC mixtures.
Biodegradation of VOC Mixtures using a Bioactive Foam Reactor II: Analysis of Microbial Community
Jang, Hyun Sup ; Shin, Shoung Kyu ; Song, Ji Hyeon ; Hwang, Sun Jin ;
Journal of The Korean Society of Civil Engineers, volume 26, issue 6B, 2006, Pages 695~701
A toluene-degrading bacterial strain was isolated from a mixed culture that was maintained using toluene as a sole carbon and energy source. The isolated bacterium was classified as Pseudomonas sp. TBD4 based on the close relationship to bacteria belonging to this genus. A bottle study to determine biodegradation rates of individual aromatic compounds showed that the biodegradation was faster in the order of toluene, benzene, styrene, and p-xylene. However, when various mixtures were subjected to TDB4, styrene was degraded at the highest rate, indicating that both toluene and p-xylene could stimulate the degradation of other substrates whereas styrene played as an inhibitor. In addition, the mixed culture and TDB4 were inoculated to the bioactive foam reactor (BFR), and the reactor performance and the corresponding change of microbial community were monitored using the fluorescent in situ hybridization (FISH) method. When an inlet concentration of the VOC mixture increased to greater than 250 ppm, the overall removal efficiency dropped significantly. The FISH measurement demonstrated that the ratio of TDB4 to the total bacteria also decreased to less than 20% along with the decline in removal efficiency in the BFR. As a result, the periodic addition of the pre-grown TDB4 might have been beneficial to achieve a stable performance in the BFR operated over an extended period.