• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.121-128
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• 2011

Long-term water treatment performance analysis was conducted for the constructed wetland treating agricultural tailwater. Studied wetland was established in 2001 and operated from June, 2002 to November, 2010. Wetland vegetation cover was shown over 90 % coverage after 2005. According to vegetation development, accumulation of sediment nutrient was observed; Organic Carbon, T-P and T-N. In addition, DO concentration and temperature was decreased in the constructed wetland output. An infiltration rate also significantly decreased due to compaction of wetland soil. A runoff coefficient was increased due to the low infiltration rate after 2005. A T-N, TSS and Chl.a removal rate was maintained constantly. However, the T-P removal rate was slightly decreased along to wetland operation because low DO concentration could increase elution of phosphorus from sediment. After constructing open water, the T-P removal rate was increased. This is because open water could accelerate the reaearation process. Consequently, over three years of vegetation development could be helpful for wetland performance. In addition, DO concentration is important factor to maintain the T-P treatment.

• KIEAE Journal
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• v.11 no.4
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• pp.71-78
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• 2011

The goal of this study is to analyze the impact of load factors on building energy consumption by using EnergyPlus program. We selected a campus building and monitored energy consumption from January 2009 to November 2010. First, we simulated energy consumption basically with weather data, building heat gain and EHP performance data. And then we simulated energy consumption with three additional parameter(infiltration, OA control and schedule). Simulation results are verified by MBE and Cv(RMSE) proposed by M&V guideline 3.0. Simulated total energy consumption was 104.3% of measurements, 4.33% of MBE, and 13.62% of Cv(RMSE). Results show infiltration and schedule were revealed as the most dominant factor of heating energy consumption and of cooling energy consumption, respectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.599-606
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• 2010

It has been reported that many slope failures in unsaturated soils are mainly caused by downward infiltration due to rainfall. The rainfall characteristics could be an important factor, and more predictable slope failures can be achieved by considering more reasonable rainfall conditions. So, a need exists that these trends of infiltration in weathered soils, which is commonly found in Korea, are assessed by considering rainfall conditions based on phenomenological approach. In this paper, numerical analyses of unsaturated soil slope under rainfall conditions are presented based on the soil-water characteristic curve in the laboratory and huff method. Then the performance of unsaturated weathered soil slopes was evaluated under various conditions after applying the effect of overburden pressure on SWCCs and fines contents. The results demonstrated that the rainfall conditions using Huff method can be very effective and the proper application on analysis is very important to enhance the prediction on unsaturated slope stability.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.184-190
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• 2002

This study was undertaken to judge the quality of air-tightened exhibition cases. Exhibition cases for artifacts display provide a layer of protection between the interior conditions in the exhibition case and the exterior fluctuating conditions of temperature and relative humidity in the museum environment. An infiltration model of the exhibition case was developed through the experimental measurements to calculate the number of air change rate in the exhibition case undergoing in a day, which represents the airtightness of the exhibition case. The results indicate that tighter exhibition cases provide greater protection against the fluctuating conditions of temperature and humidity outside. When the temperature and humi- dity difference between the exhibition case in-and-out is larger, some absorption materials should be applied to control the environmental conditions in the exhibition case.

• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.61-67
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• 2005

The purpose of this study is to evaluate the air tightness of Zero Energy Solar House(ZeSH) and to propose the construction improvement of junctions and penetrations where air infiltration was identified. Air leakage rate were measured by means of blower door test in accordance with ASTM E779-87. The results showed that ZeSH has an excellent airtightness with ACH50/20 (air change per hour at a pressure difference of 50 Pa between inside outside) of 0.34hr-1 and leakage class E by normalized leakage area of ASHRAE.

• Journal of Magnetics
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• v.20 no.2
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• pp.110-113
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• 2015

Two kinds of magnetic fluids with different volume fractions are symmetrically filled into the W0.9 photonic crystal waveguide structure. The 2D plane-wave expansion method is used to investigate the slow light properties numerically. The constant group index criterion is employed to evaluate the slow light performance. The wavelength bandwidth ${\Delta}{\lambda}$ centering at ${\lambda}_0=1550nm$ varies from 32.4 to 44.2 nm when the magnetic field factor ${\alpha}_{\parallel}$ changes from 0 to 1. And the corresponding normalized delay bandwidth product can be tuned from 0.221 to 0.258. For comparison and optimization, two infiltration cases are investigated and the more advantageous infiltration scheme is found.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.433-438
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• 2009

The main objective of this research effort is to develop the performance of C/SiC composites manufactured by LSI (Liquid Silicon Infiltration) method for solid and liquid rocket propulsion system and ensure the performance analysis technique. The high performance and reliability of C/SiC composite are proved for solid and liquid rocket propulsion system. And the performance analysis technique related to mathematical ablation model is originated.

• Journal of the Korean GEO-environmental Society
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• v.18 no.12
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• pp.13-23
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• 2017

This paper discusses about the reinforcement materials and construction method in order to cope with roadbed settlement in operating railway. In Korea, concrete tracks have been introduced to urban railways, high-speed railways, and general railways, but some recently constructed concrete tracks have experienced roadbed settlements. Reinforcement of the railway roadbed is urgent task for safe operation of railway, but it is difficult to reinforce the roadbed and there are no case history of reinforcing railway roadbed under an operating railroad track. Therefore, in this study, the target performance level for roadbed reinforcement was determined, and infiltration and solidity injection efficiency were investigated for selected reinforcement materials. As a result of the study, it was found that the generally used reinforcement materials and methods for geotechnical works need to be improved for applying in railway roadbed reinforcement.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.260-260
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• 2017

This study aims to compare the performance of TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-stability model) and TiVaSS (Time-variant Slope Stability model) in the prediction of rainfall-induced shallow landslides. TRIGRS employs one-dimensional (1-D) subsurface flow to simulate the infiltration rate, whereas a three-dimensional (3-D) model is utilized in TiVaSS. The former has been widely used in landslide modeling, while the latter was developed only recently. Both programs are used for the spatiotemporal prediction of shallow landslides caused by rainfall. The present study uses the July 2011 landslide event that occurred in Mt. Umyeon, Seoul, Korea, for validation. The performance of the two programs is evaluated by comparison with data of the actual landslides in both location and timing by using a landslide ratio for each factor of safety class ( index), which was developed for addressing point-like landslide locations. In addition, the influence of surface flow on landslide initiation is assessed. The results show that the shallow landslides predicted by the two models have characteristics that are highly consistent with those of the observed sliding sites, although the performance of TiVaSS is slightly better. Overland flow affects the buildup of the pressure head and reduces the slope stability, although this influence was not significant in this case. A slight increase in the predicted unstable area from 19.30% to 19.93% was recorded when the overland flow was considered. It is concluded that both models are suitable for application in the study area. However, although it is a well-established model requiring less input data and shorter run times, TRIGRS produces less accurate results.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.217-223
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• 1999

Mostly, water leakage took place in construction joints. In case of cable tunnels constructed by open-cut method, waterstops have been used to prevent the water leakage. But, we haven't any experience to install the waterstops in NATM cable tunnels. So, it is necessary to develope the waterstops and test the performance of it in laboratory. We manufactured cable tunnel lining quarter scale model by pouring concrete, and installed the waterstops. After filling the inside of concrete lining about two-third with water, we put the air pressure on the water, In addition, it is also carried out water leakage test for concrete lining model without waterstops. As a result, we confirmed the performance of waterstops and its adaptability. It is also tested that the performance of rubber gaskets used in concrete segments of Shield tunnelling. In addition, we determined the allowable infiltration rate for cable tunnel with non-drainage system.