• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.6
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• pp.163-173
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• 2001

This study describes the characteristics of concentrations of pollutants such as total nitrogen(T-N), total phosphorous(T-P), and chemical oxygen demand(COD) at paddy areas during 2-year irrigation periods. The most common order in average concentrations of T-P and COD is podded water > irrigation(or drainage) water > percolated water. Most of pollutants concentrations in drainage water are lower than those in irrigation water after early July due to large uptake of pollutants by rice crop and denitrification. The exponential L (load)-Q(discharge) equations for classified irrigation periods are significant at 0.001 level for irrigation and drainage waters. For drainage water, the concentrations of T-N and COD slightly decrease with discharge, while the T-P concentrations slightly increase with discharge.

• Journal of Gastric Cancer
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• v.20 no.4
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• pp.376-384
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• 2020

Purpose: The role of prophylactic abdominal drainage in total gastrectomy is not well-established. This study aimed to evaluate the efficacy of abdominal drainage in the prevention and management of major intra-abdominal complications after total gastrectomy for gastric carcinoma. Materials and Methods: We retrospectively reviewed the data of 499 patients who underwent total gastrectomy for gastric carcinoma in a high-volume institution. The patients were divided into drainage and non-drainage groups and compared for the development and management of major intra-abdominal complications, including anastomotic leak, abdominal bleeding, abdominal infection, and pancreatic fistulas. Results: The drainage group included 388 patients and the non-drainage group included 111 patients. The 2 groups showed no significant differences in clinicopathological characteristics or operative procedures, except for more frequent D2 lymphadenectomies in the drainage group. After surgery, the overall morbidity (drainage group vs. non-drainage group: 24.7% vs. 28.8%, P=0.385) and incidence of major intra-abdominal complications (6.4% vs. 6.3%, P=0.959) did not significantly differ between the two groups. The non-drainage group showed no significant increase in the incidence rate of major intra-abdominal complications in the subgroups divided by age, sex, comorbidity, operative approach, body mass index, extent of lymphadenectomy, and pathological stage. Abdominal drainage had no significant impact on early diagnosis, secondary intervention or reoperation, or recovery from major intra-abdominal complications. Conclusions: Prophylactic abdominal drainage showed little demonstrable benefit in the prevention and management of major intra-abdominal complications of total gastrectomy for gastric carcinoma.

• Geotechnical Engineering
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• v.12 no.5
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• pp.89-102
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• 1996

In order to investigate the characteristics of pressure drainage for geotextile, small-scale model tests were carried out for the horizontal and vertical geotextile drain to accelerate consolidation of foundation under embankment for the purpose of foundation reinforcement. According to the result of this study, the accumulative drainage discharge is found to increase as compressive stress of geotextile increases with logarithmic function. The drainage discharge under each step of compressive stress linearly increases with the increase of hydraulic head and its increasing rate is smaller when the compressive stress is higher. The drainage discharge shows to be greater when the number of geoteztile layers is more and the foundation material is finer. The relationship between transmissivity of geogextile and drainage discharge has positive correlation and the rate of increase is appeared to be the same regardless of foundation material and hydraulic head. And it proves that the drainage capacity of geotextile drain is determined by the transmissivity of geoteztile.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.2
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• pp.64-69
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• 1999

Drainage phenomena on the conventional fourdrinier table can be divided into two distinct zones based on the drainage mechanisms involved. In the forming zone, natural drainage is the principal water removal mechanism, while in the vacuum zone vacuum dewatering displaces water in the wet sheet with air. In this study to investigate the influence of polyelectrolyte addition on natural and vacuum dewatering a vacuum drainage tester was developed and used. Addition of PAM decreased the dryness of the wet sheet after vacuum dewatering since substantial reduction in vacuum level occurred due to flocculation of fibers. Addition of PAM, however, increased the wet web dryness when the fines content of the stock is greater than 35% indicating the presence of fines reduced the air permeability of the wet web to increase its response to vacuum dewatering. On the other hand, PEI, which flocculates the fibers and fines via patch formation, showed little impact on the drainage characteristics of the stocks.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.5 s.118
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• pp.24-30
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• 2006

This study was performed to characterize inverse emulsion type cationic polyacrylamide (PAM) and to compare with powder and salt dispersion type PAMs as a retention and drainage aid. Salt dispersion type PAM has defects of high amount of salt which increases conductivity of white water, low active polymer contents and relatively worse retention and drainage properties than others because of its low molecular weight. Powder type PAM has benefit of high active polymer contents and good retention and drainage properties, but defects of low dissolution speed and insoluble particle generation were observed. However, inverse emulsion type showed the best retention and drainage aids among them by controlling molecular weight and morphology easily and it had relatively higher active polymer contents and better solubility.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.3
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• pp.52-59
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• 2004

The greater Increase of the demand for environmental friendly materials especially for packaging industry leads to the larger interest in the reusable and recycable materials such as pulp mold. Although the pulp mold has great characteristics for packaging, some deficiency compared with other packaging material like EPS(Expandable Polystyrene) need to be overcome, for example, the relative higher cost. In this report, since the water drainage rate at the forming zone of a wet pulp mold process could have a great influence on the economical efficiency not only by increasing machine speed but also reducing the drying energy, the optimum ways for increasing drainage were investigated The mechanism of vacuum drainage In pulp mold forming was successfully evaluated by using RDA(Retention and Darinage Analyzer). Since the conditions of stock were greatly affected by the pulping time of low consistency pulper, the optimum pupling time was investigated with considerations of all stock preparation processes. The change of stock temperature and the addition of polyelectrolyte could improve the vacuum drainage rate. It was founded that the wire mesh types of mold former had a little influence on the retention because of the relatively mild vacuum drainage. However, the bigger size of dewatering hole showed better drainage rate and could reduce the plugging and con lamination of mold.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.452-458
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• 2005

In Korea, pumping pipe using gravity way by water is most popular method in drainage system. But, it is difficult to repair a drainpipe in this method because the drain pipe diameter is increased as using this method. In this research, we propose a new drainage system. The system aim for an adaptedness with buildings, freedom of plan, construction and renewal in water pipe equipments, etc. The new system is not need of incline of piping, and it uses drainage power that is changed potential energy by high velocity flow as making Siphonage at vertical pipe. Therefore, the diameter of piping can decreased than existing piping system established in the ceiling. Also because connecting position will be located at the lower part, it is changed the potential energy of drainage to the high velocity flow. In addition, drainage will be smooth because the fixture drain is linked by each drain pipes.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.72-77
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• 2016

The present study investigates noise and condensation characteristics of polyvinyl chloride (PVC), which is widely used for drainage piping materials, complex double structure by comparing to those of PVC single structure piping materials. In addition, effects of insulation on drainage noise has been measured experimentally. As the results of the experiments, noise reduction effect of PVC complex double structure is superior to that of PVC single structure in terms of elbow and vertical piping materials which are employed for drainage pipes of toilet bowls and bathtub. The insulation barely have effect on the noise reduction in case of the PVC single structure since there is almost no changes in noise occurrence even though the insulation is applied on both elbow and vertical piping materials. Temperature differences between inside and outside of the pipes have been measures for the PVC single and complex double structures as well. In consequence, outside temperature of the PVC complex double structure is higher than that of the PVC single structure. The condensation occurrence time of the PVC complex double structure shows a distinct difference from that of the PVC single structure, thus, the PVC complex double structure has outstanding effect on preventing the condensation.

• Journal of Korea Water Resources Association
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• v.52 no.4
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• pp.301-312
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• 2019

The importance of the dual drainage system model has increased as the urban flood damage has increased due to the increase of local storm due to climate change. The dual drainage model is a model for more accurately expressing the phenomena of surface flow and conduit flow. Surface runoff and pipe runoff are analyzed through the respective equations and parameters. And the results are expressed visually in various ways. Therefore, inundation analysis results of dual drainage model are used as important data for urban flood prevention plan. In this study, the applicability of the COBRA model, which can be interpreted by combining the dual drainage system with the natural watershed and the urban watershed, was investigated. And the results were compared with other dual drainage models (XP-SWMM, UFAM) to determine suitability of the results. For the same watershed, the XP-SWMM simulates the flooding characteristics of 3 types of dual drainage system model and the internal flooding characteristics due to the lack of capacity of the conduit. UFAM showed the lowest inundation analysis results compared with the other models according to characteristics of consideration of street inlet. COBRA showed the general result that the flooded area and the maximum flooding depth are proportional to the increase in rainfall. It is considered that the COBRA model is good in terms of the stability of the model considering the characteristics of the model to simulate the effective rainfall according to the soil conditions and the realistic appearance of the flooding due to the surface reservoir.

• Journal of Environmental Science International
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• v.9 no.3
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• pp.193-199
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• 2000

This study is carried out the analysis of the runoff characteristics for the design of the interior drainage systems by SWMM in urbanization basin. The basin analyzed in this study is Bumuh-chun basin which is located in Susung-gu of Taegu city. Huff method is used for rainfall distribution analysis. The optimal rainfall duration in Bumuh-chun basin is analyzed as about 90 minutes decided from comparison of arrival time and critical duration. Flood flow variation pattern is proposed through the comparison of the results of peak flow and peak time analyzed by SWMM about pre-urbanization and post-urbanization of Bumuh-chun basin. It is known that the variation of arrival time caused by the rapid increase of pavement rate in the upper area shows about 20∼25 minutes faster than pre- urbanization. Therefore, the management of surface water for design of water supply and drainage, and channel alteration has to considered the variation of geological factors according to urbanization.