• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.857-865
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• 2006

The submerged barrier, employed in a reactor, divided a reactor into sludge settling zone and mixing zone according to flow type. In spite of mixing in the mixing zone, the lower part of sludge settling zone than the top of barrier was in a steady flow due to the barrier, which prevented the turbulent flow, produced from the mixing zone, from being diffused into the sludge settling zone. Therefore, the sludges in the mixing zone flowed backward over the barrier into the upper part of the sludge settling zone by turbulent flow and settled down in the sludge settling zone by the force of gravity. When barrier/water level ratio was 0.5, most sludges almost did not settle down in tile sludge settling zone because the sludges were directly affected by the turbulent flow, generated from mixer in the mixing zone. At 0.63 of barrier/water level ratio, sludge in the middle part of sludge settling zone rocked from side to side weakly. And sludge in the lower part became piled up on the bottom over this ratio. After 10minutes of sludge settling, the lower part of sludge settling zone was over 5000mg/L of sludge concentration although intial sludge concentration was 2300mg/L. By using the submerged barrier and the flow types, it could transfer sludge from this to that.

• The Journal of Internal Korean Medicine
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• v.18 no.2
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• pp.131-150
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• 1997

As to the effects of drinking on the cerebrovascular system, the result of studies by Eastern-Western medicine indicate the following conclusions: 1. Oriental medical studies show drinking causes 'Dam-em', 'Dam-tak', and 'Seub-yul' and is, thus related to hypertension and hyperlipidemia. 2. Oriental medical studies also show that hypertension and hyperlipidemia, which includes apoplexy, a dizziness, headaches and 'Gan-yang', are caused by 'Dam-em', 'Dam-tak' and 'Heul-uh'. In most cases of obesity. which is piled 'Seub-dam' in the spleen and stomach, is caused by alcohol consumption. 3. Large amounts of alcohol consumption is a dangerous factor in many kinds of cerebrovascular attacks but under the middle grade of drinking it is not harmful. And it is a predominant theory that a small quantity of alcohol consumption is good for preventing cerebrovascular attacks. 4. Taking a brain computed tomography after alcohol has been introduced into the system reveals strange symptoms like ventricle dilatation, cerebral atrophy, and pathologic histological degeneration. 5. Alcohol is related to hypertension, hyperlipidemia, obesity which are dangerous factors in cerebrovascular attacks. This is especially true with hypertension and obesity. 6. Western medicine says, because of the close relations between hypertension, hyperlipidemia, and the grade of obesity, drinking increases the chances of cerebrovascular attacks. Our findings show that reducing alcohol intake, an environmental factor, will help prevent cerebrovascular attacks.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.606-609
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• 1997

Technology in fire sprinklers has exploded. There is more private fire sprinkler research now than ever before. New technology in fire sprinklers has tested the existing standard and found that it was wrong in some cases, it has provided new sprinklers that control fire better while reducing the cost of the overall system. This expansion of the types and applications of fire sprinklers has created a great need for education for the Authorities Having Jurisdiction and the Engineer as they must be able to make informed decisions regarding this new technology. Significant research has been done at Factory Mutual Research Corporation and Underwriters Laboratory in the United States. Full scale fire testing is done to prove any new technology did not lower the level of protection of existing fire sprinkler system installations. In each and every case, the existing level of fire protection was the baseline against which the new sprinklers were tested. This level can not be lowered for the test to be considered a success. This is intended to be an overview of the developments in fire sprinklers. Although extensive detail is not included, the overall aspects of these developments can be discussed. The research that will be covered will include the following general subjects: high piled and rack storage sprinkler protection without in-rack sprinklers, extended coverage and quick response sprinklers for ordinary and light hazard occupancies, as well as special sprinklers and their applications.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.203-206
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• 2008

Kick motor(KM) for KSLV-I second stage propulsion system is the main hardware that is necessary for launching satellite to it's track. The mass of the kick motor changes with combustion time because the heat insulator is ablated and propellant is used and slag is piled up. We predicted mass change with the flight time using ground combustion data of KM composed of case, propellant, nozzle, ignitor and slag. The mass prediction of kick motor can be used for calculating the two stage mass and center of gravity history.

• Geomechanics and Engineering
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• v.11 no.6
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• pp.805-820
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• 2016

A fully coupled non-linear effective stress response finite difference (FD) model is built to survey the counter-intuitive recent findings on the reliance of pore water pressure ratio on foundation contact pressure. Two alternative design scenarios for a benchmark problem are explored and contrasted in the light of construction emission rates using the EFFC-DFI methodology. A strain-hardening effective stress plasticity model is adopted to simulate the dynamic loading. A combination of input motions, contact pressure, initial vertical total pressure and distance to foundation centreline are employed, as model variables, to further investigate the control of permanent and variable actions on the residual pore pressure ratio. The model is verified against the Ghosh and Madabhushi high acceleration field test database. The outputs of this work are aimed to improve the current computer-aided seismic foundation design that relies on ground's packing state and consistency. The results confirm that on seismic excitation of shallow foundations, the likelihood of effective stress loss is greater in deeper depths and across free field. For the benchmark problem, adopting a shallow foundation system instead of piled foundation benefitted in a 75% less emission rate, a marked proportion of which is owed to reduced materials and haulage carbon cost.

• Design & Manufacturing
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• v.12 no.3
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• pp.19-24
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• 2018

Fused deposition Modeling (FDM) is one of the most widely used for the prototype of parts at ease. The FDM 3D printing method is a lamination manufacturing method that the resin is melted at a high temperature and piled up one by one. Another term is also referred to as FFF (Fused Filament Fabrication). 3D printing technology is mainly used only in the area of prototype production, not in production of commercial products. Therefore, if FDM 3D printer is applied to the product process of commercial products when considered, the strength and dimensional accuracy of the manufactured product is expected to be important. In this study, the mechanical properties of parts made by 3D printing with FDM method were investigated. The aim of this work is to examine how the mechanical properties of the FDM parts, by changing of processing FDM printing direction and the height of stacking layer is affected. The effect of the lamination direction and the height of the stacking layer, which are set as variables in the lamination process, by using the tensile specimen and impact specimen after the FDM manufacturing process were investigated and analyzed. The PLA (Poly Lactic Acid) was used as the filament materials for the 3D printing.

• Journal of Korean Society of Archives and Records Management
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• v.21 no.3
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• pp.217-225
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• 2021

This article delves into community archives based on the archival project of Dongjak-gu Public Library on the search toward sustainability. Dongjak-gu has conducted a local archiving project that involves collecting local records, focusing on the role of local public institutions as representative districts in the local region after the library was established in September 2013. Thus far, we are managing the project and records that are piled at the public library, and as the placement for archiving local records conducted in a local public library does not match its role, the national/city/province system for archiving local records faces a challenge for long-term sustainability. Therefore, we would like to present an idea for sustainability by discussing our concerns and experiences in this paper.

• Structural Engineering and Mechanics
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• v.84 no.5
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• pp.699-706
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• 2022

Settlement control techniques are critical for the safety of shield tunnel constructions, especially for facing complex situations. In this study, the shield tunnel structure from Huaita east road station to Heping Road station in Xuzhou metro No.3 line (China) is taken as engineering background, which has various complex problems of the upper-soft and lower-hard composite stratum conditions, twin curve shield tunnels, and underpass the foundation of the piled raft. The deformation characteristics of shield tunnelling passing through buildings are explored. Subsequently, comprehensive research methods of numerical simulation and field measurement are adopted to analyzing the effectiveness of settlement control by using the top grouting technique. The results show that the settlement of the buildings has obvious spatial characteristics, and the hysteresis effect can be obviously observed in soil deformation caused by shield construction. Meanwhile, the two shield constructions can cause repeated disturbances, reducing the soil deformation's hysteresis effect. Moreover, the shield tunnel's differential settlement is too large when a single line passes through, and the shield construction of the outer curve can cause more significant disturbance in the tunnel than the inside curve. Notably, the proposed process control parameters and secondary topgrouting method can effectively control the deformation of the shield tunnel, especially for the long-term deformation.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4350-4356
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• 2023

Radiation detection systems working at high count rates suffer from the overlapping of their output electric pulses, known as pulse pile-up phenomenon, resulting in spectrum distortion and degradation of the energy resolution. Pulse tail extrapolation is a pile-up correction method which tries to restore the shifted baseline of a piled-up pulse by extrapolating the overlapped part of its preceding pulse. This needs a mathematical model which is almost always nonlinear, fitted usually by a nonlinear least squares (NLS) technique. NLS is an iterative, potentially time-consuming method. The main idea of the present study is to replace the NLS technique by an integration-based non-iterative method (NIM) for pulse tail extrapolation by an exponential model. The idea of linear extrapolation, as another non-iterative method, is also investigated. Analysis of experimental data of a NaI(Tl) radiation detector shows that the proposed non-iterative method is able to provide a corrected spectrum quite similar with the NLS method, with a dramatically reduced computation time and complexity of the algorithm. The linear extrapolation approach suffers from a poor energy resolution and throughput rate in comparison with NIM and NLS techniques, but provides the shortest computation time.

• Korean Journal of Environment and Ecology
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• v.11 no.1
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• pp.126-132
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• 1997

Nanji-do is an island in Seoul, the area is 272ha, and in which gad was piled up waste discharged from Seoul metropolitan for 15 years(form March 1978 to March 1993). The volume of waste is 92, 000, 000m$^{2}$. The actual vegetation area of Nanji-do is 191ha, and the area of woody plant is 31ha. The rest area is covered by herbaceaus plant. In actual vegetation area of woody plant, Robinia pseudoacacia community and Salix pseudo-lasiogyne community are 83%. The soil pH is alkaline, though general soil pH is acid in Seoul. There is no relation with soil condition and actual vegetation. The result of this study, actual vegetation of Nanji-do don't help the establishment of vegetation restoration after soil stabilization construction. And so following a countermeasure is proposed. 1) Selection of adequate species by an experiment of planting pioneer species, native species, and dietary species 2) Establishment of an adequate planting plan and development of slope stabilization method by planting of native species 3) Establishment of a restoration plan of animal ecosystem by survey for animal ecosystem