• Geomechanics and Engineering
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• v.24 no.5
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• pp.479-490
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• 2021

Pre-drainage of groundwater in the roof aquifer by boreholes is the main method for prevention of roof water disaster, and the drop in the water level during the drainage leads to the variation of the local stress in the overlying strata. Based on a multitude of boreholes for groundwater drainage from aquifer above the 1303 mining face of Longyun Coal Mine, theoretical analysis and numerical simulation are used to investigate the local stress variation in the process of borehole drainage. The results show that due to the drop in the water level of the roof aquifer during the drainage, the stress around the borehole gradually evolved. From the center of the borehole to the outside, a stress-relaxed zone, a stress-elevated zone, and a stress-recovered zone are sequentially formed. Along with the expansion of drainage influence, the stress peak in the stress-elevated zone also moves to the outside. When the radius of influence develops to the maximum, the stress peak position no longer moves outward. When the coal mining face advances to the drainage influence range, the abutment pressure in front of the mining face is superimposed with the high local stress around the borehole, which increases the risk of stress concentration. The present study provides a reference for the stress concentration caused by borehole drainage, which can be potentially utilized in the optimal arrangement of drainage boreholes in underground mining.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.109-116
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• 1999

This study is to make clear for the characteristics of radial drainage consolidation/permeability At the result of the radial drainage consolidation / permeability test, the permeability of outflow drainage condition is higher than Inflow drainage condition and the time for the end of consolidation, outflow drainage condition is shorter than inflow drainage condition. So drainage area ratio test and control of hydraulic gradient test are carry out to analysis this result. Finally, compared with the characteristics on the condition of inflow and outflow permeability and consolidation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.1
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• pp.1-9
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• 2017

Recently, it is increasing the grape farm which is converted from paddy field to orchard. These soil which are poor drainage extremely also can be damaged a lot by excessive water or flooding during heavy rain season on summer. Therefore the aim of this study was carried out to measure the changes of soil water potential and to compare the growth responses of 'Jinok' (Vitis spp.) and 'Campbell Early' (V. labruscana) grapes under three drainage systems (control, conventional drainage, and under drainage). After heavy rain, soil water potential holding times above -15 kpa applied water excessive were 352, 348 and 180 hours in control, conventional, and under drainage systems, respectively. The clay content of the under drainage system was lower than the other systems about 8-12%. The crop water stress index was lowest in the under drainage and highest in the control. Also, photosynthetic rate has showed the opposite result with crop water stress index. It was significant differences between the treatments but, the value has not shown significantly different between the varieties. In addition, leaf area and the trunk growth rate was more effective in under drainage than in the control and conventional drainage.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.481-484
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• 2003

Sulfide minerals contacted with air and water in coal seam cause oxidation reactions. This oxidation reactions make low pH of groundwater and surface water(Acid Drainage). The reddish brown precipitate collected from the cut slope of the study area was estimated using the X-Ray Diffractometer(XRD). XRD results show that the cut slope was affected by Acid Drainage. The cut slope exposured to Acid Drainage become weak about chemical weathering and defile the appearance of the road. Drainage facilities are very important in Cut Slope under Acid Drainage influence. Reactions between Coal seam and water cause chemical weathering and environmental problem. Therefore It is important to control the transfer paths of groundwater and surface water and to install water collecting facilities

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.9 no.1
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• pp.30-35
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• 2013

The four principles of treatment of odontogenic infection are as follows : (1) removal of the cause, (2) establishment of drainage, (3) institution of antibiotic therapy, and (4) provision of supportive care, including proper rest and nutrition. A separate incision is required to establish drainage, especially in the case of extensive fascial space infections. There are four principle causes for active bleeding in the immediate incision & drainage phase; (1) vascular wall alteration (infection, scurvy, chemicals), (2) disorder of platelet function, (3) thrombocytopenic purpuras, (4) disorders of coagulation (liver disease, anticoagulation drug). If the hemorrhage from incision & drainage site is aggressive, the site must be packed with proper wet gauze and wound closure & drainage dressing are applied. The specific causes of bleeding may be associated with hypoxia, changes in the pH of blood & chemical changes affecting vascular contractility and blood clotting. This is a case report of bleeding control by the circumferential suture & drainage on active bleeding incision & drainage site of temporal space abscess due to advanced odontogenic infection in a multiple medically compromised disabled patient.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.12-18
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• 2010

Irrigation management methods controlled by integrated solar radiation (ISR) or drainage level sensor were evaluated in rockwool or coir bag culture as tomato (Solanum lycopersicum L.) production system. Substrate water content and drainage percentage were more stable in the drainage level sensor method than in the ISR method regardless of substrate type. Total yield and marketable yield were high in the drainage level sensor method, but not between substrates in the same irrigation management method. Sugar content was affected more by the substrate type than irrigation method. The drainage level sensor method was elucidated to be better than the ISR method regardless of substrate type.

• Tuberculosis and Respiratory Diseases
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• v.76 no.4
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• pp.160-162
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• 2014

Increasing incidence of pleural infection has been reported worldwide in recent decades. The pathogens responsible for pleural infection are changing and differ from those in community acquired pneumonia. The main treatments for pleural infection are antibiotics and drainage of infected pleural fluid. The efficacy of intrapleural fibrinolytics remains unclear, although a recent randomized control study showed that the novel combination of tissue plasminogen activator and deoxyribonuclease had improved clinical outcomes. Surgical drainage is a critical treatment in patient with progression of sepsis and failure in tube drainage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.697-704
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• 1995

This experiment was carried out to elucidate the effect of the midsummer drainage times and some growth regulators on lodging characters, lodging and yield in puddled-soil drill seeding in rice. Dongjinbyeo, the mid-late maturing rice variety was seeded at May 11 by seeding machine with 4cm of furrow depth. Experimental plots were divided two main treatment without midsummer drain and two time drains (30 and 50 days after seeding), Inabenfide(IBF) was applied 40days before heading(DBH) and IBP was applied at 30DBH, respectively. Culm length was shorten, the wall of N$_4$ was thicken, and the breaking weight was increased at two time drainage and growth regulators applied in order of Inabenfide, IBP, and Control. Lodging wasn't occurred at two time drainage but it was occurred at none drainage in the order of Control, IBP, and Inabenfide applied. Yield was higher at two time drainage compared with none drainage and higher in order of Inabenfide, IBP and Control in none drainage but wasn't significantly different among growth regulators applied in two time drainage. Therefore, two times midsummer soil drying is recommendable management method for puddled -soil drill seeding of rice. Rice, Direct seeding, Puddled-soil, Drill seeding, Midsummer drainage, Growth regulator, Lodging.

• Journal of Korea Water Resources Association
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• v.41 no.8
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• pp.773-784
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• 2008

The present study was carried out to examine flow properties in linear drainage channels such as road surface drainage facilities. The finite difference formulation for the varied flow analysis was solved for flow profiles in the channels. Starting the first step at the control section, the Newton-Raphson method was applied for producing numerical solutions of the equation. We considered two types of linear drainage channels, a channel with one outlet at downstream end and a channel with two outlets at both ends. Moreover, the flow analysis for various channel slopes was performed. However, we considered channels with the two outlets of slopes satisfying the condition that the both ends are the control section. The maximum of those slopes was decided from the relation between the channel slope and the location of control section. The flow of a channel with one outlet was calculated upward and downward from the control section existing in channel or upward from the control section at downstream end. The flow of a channel with two outlets at both ends were calculated for upstream and downstream channel segments divided by the water dividend, respectively and the flow analysis was completed when the water depth at the water dividend calculated from upstream end was equal to that calculated from downstream end. If the slope was larger than the critical slope, the channel with two outlets was likely to behave like the channel with one outlet. The maximum water depth was investigated and compared with that calculated additionally from the uniform flow analysis. The uniform flow analysis was likely to lead a excessive design of a drainage channel with mild slope.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.19-24
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• 2010

The experiment was implemented to introduce the drainage electrode irrigation system as early as possible after transplanting in order to save the nutrient solution in a convenient way. Drainage electrode irrigation method was introduced 15, 19 or 22 days after transplanting after irrigation was firstly controlled by time clock. Time clock method was also treated as a control plot. Drainage electrode method could be adopted from 15 days after transplanting, 15 days earlier than the present introducing time. The growth and yield was better in treatments with drainage electrode method. Water and fertilizer use efficiency were the highest in the treatment of 15 days, the lowest in time clock treatment.