• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.53-61
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• 1995

Analyses of subsurface drainage effects of farmland with respect to pipe and envelop material are made by the laboratory experiments using soil box to give basic information for the subsurface drainage system planning and design. Three different diameter PVC perforated pipes and a mesh pipe are used with envelop materials such as sand, rice bran, and crushed stone. Steady state subsurface drainage flow rate increased as envelop material changed from sand to rice bran and crushed stone. This indicates that as the hydraulic conductivity of the envelop material increases, the drainage flow rate increases. On the other hand, for a given envelop material, the mesh pipe which has the largest openning area shows the largest flow rate while small diameter PVC pipes show small flow rates. This tells that as the openning area and pipe diameter increase, the flow rate increases, too. Therefore, selection of pipe and envelop material should be made in accordance with the design drainage flow rate. Unsteady state subsurface drainage flow rate with respect to time differs for different envelop material. In case the sand was used as an envelop material, the small diameter PVC pipes show larger flow rates than the large diameter PVC pipe and mesh pipe. When the rice bran was used, the mesh pipe shows the largest flow rate, while small diameter pipes show smaller flow rates. In case the crushed stone was used as an envelop material, the large diameter PVC pipe and mesh pipe show larger flow rates, while small diameter pipes show a little bit smaller flow rates. However, the variation of flow rates among different pipes is the smallest when the crushed stone is used. The flow rate curve with respect to the pipe changes little for the crushed stone envelop which has a large hydraulic conductivity, while that changes much for the sand and rice bran envelops. However, it is difficult to draw a consistent relationship between the drainage flow rate and pipe for all the envelop materials. Since the subsurface drainage experiments are made only under the restricted laboratory condition in this study, further study including field experiment is required.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.2
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• pp.10-16
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• 2004

Structures and strengths of paper have been studied by analyzing fibers characteristics depending on refining methods. Mixing ratio of softwood and hardwood fibers and fibers characteristics have been analyzed for paper quality improvement. In this study flocculation and drainage of fibers were analyzed to improve the production efficiency and paper product's quality. Floc size and drainage rate depending on stock consistency and fines content were analyzed. Total amount of drainage during drainage process was measured quantitatively by using DI(drainage index). Floc size, viscosity of floc and dewatering times were also measured. In the case of refining load $2.8 kg_f$ , drainage was occurred by filtration mechanism rather than thickening mechanism because drainage resistance increased by fibrillation of fibers. Therefore, the drainage rate of $2.8 kg_f$ refining load stock was slower than that of $5.6 kg_f$.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.3
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• pp.214-220
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• 2007

The effects of soil percolation rate on $CH_4$ and $N_2O$ emissions were investigated from paddy fields with different drainage systems. Subsurface tile drainage plot of soil percolation rate $11.9mm\;d^{-1}$ and non-subsurface drainage plots of soil percolation rate $7.4mm\;d^{-1}$ and $6.9mm\;d^{-1}$ were designed. The effects of rice straw application were measured at each drainage plots. The subsurface tile drainage plot of soil percolation rate $11.9mm\;d^{-1}$ showed the lower emission amount both of $CH_4$ and $N_2O$ among treatments. In the subsurface tile drainage plot of $11.9mm\;d^{-1}$ percolation rate, 46% of $CH_4$ and 33% of $N_2O$ emission amounts were reduced in comparison of non-subsurface drainage plot of $6.9mm\;d^{-1}$ percolation rate. With rice straw application, the $CH_4$ emission amount was 2.1 times to that from no-applied plot, the $N_2O$ emission amount was not affected by rice straw application.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.3
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• pp.21-29
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• 2011

Recently, the use of recycled fibers was increased in order to replace the virgin pulp for low production cost and forest conservation. However, the recycled fibers decreases drainage rate, papermaking efficiency and product quality by short fibers and low wettability because of hornification. To overcome the limitation of low drainage rate, the technology of organic fillers were applied. Wooden fillers gave high bulk and stiffness of paper, but they reduced the strength of paper. In order to improve strength properties 4 types of strength additives were added and analyzed. Cationic starch, branched strength additive, linear wet strength additive, and linear dry strength additive were used. The drainage rate and paper properties such as bulk, air permeability and tensile strength were measured. As results of analysis, addition of branch type of strength agent such as C-starch was effective than linear type of strength agent in the drainage rate. Nevertheless there was no effect on the drainage rate by adding the pretreated wooden fillers. By adding the pretreated wooden fillers, bulk, air permeability and tensile strength of handsheets were improved with low dosage than non-pretreated fillers.

• 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.

• Water for future
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• v.9 no.2
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• pp.67-75
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• 1976

With 9 existng reservoirs selected in the Sab-Gyo River Basin, the sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoirs capacity. The reservoirs has a total drainage area of 6,792 ha, with a total capacity of 1,204.09 ha-m, and are short of water supply due to reduction of reservoirs capacity. Annual sedimention in the reservcire is relation to the drainage area, the mean of annual rain fall, and the slop of drainage area. The results of obtained from the investigation are summarized as follow; (1) A sediment deposition rate is very high, being about $9.19{m}^3/ha$ of drainage area, and resulting in the average decrease of reservoir capacity by 19.1%. This high rate of deposition could be mainly attributed to the serve denvdation of forests due to disor derly cuttings of tree. (2) An average unit storage of 415.8mm as the time of initial construation is decreesed to 315.59mm at present, as resultting, we could'nt supply water at 566.24ha. (3) A sediment deposition rate as a relation to the capacity of unit drainage area is as follow; $Qs=1.43 (c/a)^{0.531}$ (4) A sediment deposition rate as a relation to the mean of annval rainfall is as follow; $Qs=672.61 p^{0.024}$ (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow; $Qs=267.21 S^{0.597}$

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.99-107
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• 2001

Objective : Hydrocephalus and vasospasm are the common complications following subarachnoid hemorrhage (SAH). In spite of development of perioperative management and operative technique, hydrocephalus cause neurological deficit and poor prognosis. Usually CSF drainage procedure(external ventricular drainage(EVD) or shunt) is needed in hydrocephalus following SAH. The aim of this study was to investigate whether the need for shunting and the outcome after shunting in hydrocephaus following SAH can be related to the duration, daily and total amount of cerebrospinal fluid(CSF) drainage at EVD. Material and Method : IVH is one of several factors which cause hydrocephalus. In this retrospective study, firstly we investigated the incidence of IVH in total cases and frequency of IVH according to aneurysmal site and then prognosis of IVH following SAH. Among 629 patients with SAH, hydrocephalus was diagnosed by CT scan and symptoms. And then those 102 hydrocephalus following SAH were divided into two groups which were hydrocephalus with IVH group and without IVH group. In these two groups, we investigated and compared the incidence of hydrocephalus in all case, frequency of hydrocephalus according to aneurysmal site, the outcome according to H-H grade on admission and the need rate of shunt, etc. Of those hydrocephalus, 100 EVD procedures were done. The duration, daily and total amount of CSF drainage at EVD were investigated. Fifty cases expired during EVD was excluded. We analyzed whether the need rate of shunt and the final outcome after shunting can be related to IVH, the duration and daily and total amount of CSF drainage. Result : The incidence of hydrocephalus following SAH was 20%(with IVH group ; 64%, without IVH group ; 11%). As H-H grade on admission was better, the outcome of hydrocephalus was also better. The mortality rate of hydrocephalus with IVH was 64% which was higher than 40% that of hydrocephalus without IVH. The need rate of shunt in all cases of hydrocephalus following SAH was 20%, but those with IVH group excluding expired patients before shunt was 40%. This was very similar to 41% of the need rate of shunt in hydrocephalus without IVH. The total amount of CSF drainage was statistically related to the need rate of shunt(total amount : need rate of shunt/<1000cc : 15%, 1000-2000cc : 40%, >2000cc : 50%). The duration and daily amount of CSF drainage were not statistically related to the need rate of shunt, but as daily amount of CSF drainage was more and duration was longer, the need rate of shunt was increased(daily amount : need rate of shunt /<100cc : 16%, 100-200cc : 25%, >200cc : 40%//duration : need rate of shunt/<1week : 8%, 1-2weeks : 30%, >2weeks : 47%), and also the final outcome after shunting was poor. Especially the total amount of CSF drainage was significant related to the final outcome after shunting(total amount : GOS/<1000cc : I&II(3/4), 1000-2000cc : II(2/4), III(2/4), >2000cc : III&IV(6/7)). Conclusion : This study revealed that the incidence and mortality rate of hydrocephalus following SAH were influenced by IVH. So SAH associated IVH has the higher incidence of hydrocephalus and poor outcome. As the CSF drainage amount was more and duration of drainage was longer, the need rate of shunt was increased and the final outcome after shunting was poor. Especially the total amount of CSF drainage were strongly related to the need rate of shunt and the outcome after shunting.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2543-2546
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• 2015

Purpose: Percutaneous transhepatic biliary drainage (PTBD) is a form of palliative care for patients with malignant obstructive jaundice. We here compared the infection incidence between internal-external and external drainage for patients with malignant obstructive jaundice. Methods: Patients with malignant obstructive jaundice without infection before surgery receiving internal-external or external drainage from January 2008 to July 2014 were recruited. According to percutaneous transhepatic cholangiography (PTC), if the guide wire could pass through the occlusion and enter the duodenum, we recommended internal-external drainage, and external drainage biliary drainage was set up if the occlusion was not crossed. All patients with infection after procedure received a cultivation of blood and a bile bacteriological test. Results: Among 110 patients with malignant obstructive jaundice, 22 (52.4%) were diagnosed with infection after the procedure in the internal-external drainage group, whereas 19 (27.9%) patients were so affected in the external drainage group, the difference being significant (p<0.05). In 8 patients (36.3%) in the internal-external group infection was controlled, as compared to 12 (63.1%) in the external group (p< 0.05). The mortality rate for patients with infection not controlled in internal-external group in one month was 42.8%, while this rate in external group was 28.6% (p< 0.05). Conclusion: External drainage is a good choice, which could significantly reduce the chance of biliary infection caused by bacteria, and decrease the mortality rate at one month and improve the long-term prognosis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3840-3847
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• 1975

With 30 excisting reservoirs in the Chin-Young area, the Sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoir capacity. The reservoirs has a total drainage area of 3l4l ha, with a total capacity of 43.23 ha-m, and are short of water supply due to reduction of reservoir capacity, Annual sedimentation in the reservoir is relation to the drainage area, the mean of annual rainfall, and the slop of drainage area. The results of obtained from the investigation are summarized as follows: (1) A Sediment deposition rate is high, being about 7.03㎥/ha of drainage area, and resulting in the overage decrease of reservoir capacity by 16.1%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of tree. (2) An average unit storageof 116mm as the time of initial construction is decreased to 95.6mm at present. This phenomena cause a greater storage of irrigation water, sinceit was assumed that original storage quantity itself was already in short. (3) A sediment deposition rate as a relation to the capacity of unit drainge area is as follow: Qs=1.27(C/A)0.6 and standard deviation is 185.5㎥/$\textrm{km}^2$/year. (4) A sediment deposition rate as a relation to the mean of annual rainfall is as follow: Qs=21.9p10.5 and the standard deviation is 364.8㎥/$\textrm{km}^2$/year. (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow: Qs=39.6S0.75 and the standard deviation is 190.2㎥/$\textrm{km}^2$/year (6) Asediment deposition rate as a relation to the drainage area, mean of rainfall, mean of slope of drainage area is: Log Qs=0.197+0.108LogA-6.72LogP+2.20LogS and the standard deviation is 92.4㎥/$\textrm{km}^2$/year

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.173-180
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• 2004

In this study, a consolidometer for radially inward drainage under constant rate of strain (CRS) loading was developed. Theoretical solutions for determining the effective vertical stress and the coefficient of consolidation from the test result were also proposed. Reconstituted kaolinite samples which were consolidated up to 130 kPa were used to verify the developed consolidometer and the theory. Comparative experiments with CRS loading and incremental loading (IL) were carried out in radially in ward drainage as well as vertical and radially outward drainage. The results obtained from the developed CRS loading test agreed consistently with those of the conventional incremental loading test according to drainage directions. And the effect of drainage direction and drain diameter to consolidation characteristics was also evaluated. From the test results the applicability and the reliability of the suggested method were verified.