• International Journal of Highway Engineering
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• v.12 no.4
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• pp.131-137
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• 2010

The stormwater runoff from rest areas in highways are known as more polluted compared to highways because of more vehicle activities. This study is performed to find pollutant characteristics in the rest areas in the magnitude of statistical pollutant concentrations during storms. Washoff characteristics of pollutants from rest areas by monitoring of rainfall, runoff rate and runoff samples were evaluated. High concentrations of pollutants in runoff were observed at the beginning of runoff and rapid decrease thereafter, indicating that first-flush effects are clearly occurred. Event Mean Concentrations(EMCs) of TSS, COD, TN, and TP are estimated to be in the range of 31.04-127.11mg/L, 35.5-369.5mg/L, 2.62-9.86 mg/L, and 0.53-1.96mg/L, respectively. Heavy metals in runoff showed relatively high values, possibly due to the abrasion of brake pad or tire while cars are slowly moving for parking. EMCs of total Pb, total Cu, and total Ni are in the range of $1206-16293{\mu}g/L$, $237-7906{\mu}g/L$, and $53-6372{\mu}g/L$, respectively. Pollutant loading per rest area calculated by using EMC, flowrate and target area is also described for each pollutant.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.41-47
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• 2022

In this study, rainfall water outlet water quality monitoring was performed on the C industrial complex to evaluate the characteristics of non-point pollutant runoff from the industrial complex during rainfall and to use it as basic data for calculating the load and unit of non-point pollutant. As a result of calculating EMC according to the outflow amount by rainfall event, the 1st rainfall showed EMCs ranges of BOD, COD_Mn, SS, T-N, and T-P of 1.32~48.76, 3.32~43.75, 2.89~199.43, 2.76~8.93, 0.08~068, and the 2nd rainfall was 0.5~2.9, 2.71~7.13, 2.82~174.94, 1.33~4.03, 0.01~1.28 mg/L, respectively. As a result of calculating the ratio of cumulative outflow and cumulative pollution load, most of the pollution load was less than the rainfall outflow, but over time, the initial washing phenomenon occurred as the ratio of cumulative rainfall outflow and cumulative pollution load increased to more than 1.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.605-613
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• 2006

Discharge characteristics of non-point source pollutant and load amount of the discharge in the urban area were investigated in the Pungyeongjeong-stream basin and the Yongbong-stream basin in this present study. The land use of the studied basins were divided into paddy field, industrial complex area, combined sewage system, separate sewer system and point sources discharge. The descriptive statistics on the event mean concentrations (EMCs) of non-point pollutants by the the land use showed in the range of 4.43-32.28 mg/L for BOD and 8.27~56.17 mg/L for COD. The highest concentration was shown from the combined sewage system. The EMC of SS at the paddy field in the Pungyeongjeong-stream basin showed the highest range with the values ~ from 35.76 to 358.86 mg/L, which might have been influenced by a levee construction in the adjacent of the area. The relatively high concentration values of 4.43~32.28 mg/L and 1.617.13 mg/L emerged from TN and TP,respectively, at the discharge points of the both stream basins.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.314-320
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• 2006

Diffuse pollution from an urban area contributes to the significant pollution loading to a receiving water body. In this paper, rainfall runoffs from an urban basin with combined sewer systems located in the city of Daejeon were monitored to measure the rainfall runoff discharge rates and pollutant concentrations. Strong first flush effects were observed for all monitored rainfall runoffs. The first flush effects were closely related to rainfall intensity, while suspended solids were closely related to pollutant constituents. The observed averaged Event Mean Concentrations (EMCs) of Combined Sewer Overflows (CSOs) were 536.1 mg SS/L, 467.7 mg CODcr/L, 142.7 mg BOD/L, 16.5 mg TN/L, and 13.5 mg TP/L. Storage volumes for containing the first flush to improve water quality of the receiving stream can be estimated based on suspended solid concentration. In this study, retainment of the first flush equivalent to 5mm of precipitation could reduce diffuse pollution loading induced by CSOs to a receiving water body by up to 80% of suspended solid loading.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.631-640
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• 2004

This research was conducted to understand the magnitude and nature of the stormwater emissions with the goal of quantifying stormwater pollutant concentrations and mass emission rates of pollutants. Eight highway sites in Southern California area were monitored for three years with collecting of grab and flow-weighted composite samples, rainfall and runoff flow. Generally the EMCs cannot be determined by simple statistical averaging of measured pollutant concentrations because of random characteristics of runoff quality and quantity. Therefore, this manuscripts will show a new EMC determination method. The EMC ranges of 95% confidence intervals are 102.78-216.37mg/L for TSS, 104.53-251.79mg/L for COD, 5.42-10.58mg/L for oil & grease and 2.42-10.18mg/L for TKN. The ranges of washed-off mass loading are determined to $0.06g/m^2-17.27g/m^2$ for TSS and $0.1-3.23g/m^2$for COD.

• Journal of Korean Society on Water Environment
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• v.33 no.1
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• pp.97-106
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• 2017

In this study, the characteristics of nonpoint source pollutant loads from separate sewer overflow (SSO) and combined sewer overflow (CSO) were evaluated during 2016 in Namyangju city, Korea. Five rainfall events were monitored during 2016 with ranging from 14.5 mm to 121.5 mm. The runoff ratio of CSO was higher than that of SSO because only design volume of maximum sanitary sewer ($1Q_h$) was transported and treated and $2Q_h$ was overflowed to waterbody during rainy day although combined sewer system was designed to transport $3Q_h$ to treatment system. The event mean concentrations (EMCs) and pollutant loads from CSO were higher than those from SSO. BOD and COD of CSO, and TOC and TN of SSO represented distinct first flush phenomena. The inadequate management in combined sewer system from which the untreated $2Q_h$ from CSO was overflowed to waterbody during rainy day could influence on high pollutant loads and first flushing. Treating $2Q_h$ from CSO, source control such as low impact development, and treating outflow from SSO were strongly recommended to control non-point source pollution in urban area.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.4
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• pp.11-19
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• 2011

PADDIMOD2 was deloped to estimate nonpoint source pollution from paddy rice fields. The PADDIMOD2 was enhanced to estimate runoff and pollutant load during non-growing as well as growing season and to be easily used for public by development of Excel based system. Nutrient concentration and hydrology were based on Dirac delta function and continuous source function, and tank model for growing season and Event Mean Concentrations (EMCs) and SCS-Curve Number method for non-growing season. The PADDIMOD2 consists of three main component (input data, parameters data, and output data) by including eight Excel spread sheets. As a result of model application, total precipitation and irrigation were 1,051.7 mm and 439.2 mm, respectivley and surface runoff and water loss including infiltration and evapotranspiration were 463.0 mm and 947.9 mm, respectively. Annual nutrient loadings of T-N and T-P from study area were 6.7 kg/$km^2$/day and 0.5 kg/$km^2$/day, respectively. Development of PADDIMOD2 was focused on minimizing input data and maximizing user friendly system and is expected to be useful tool to evaluate various non-structure BMPs and estimate unit load from paddy rice fields for application at Korean TMDL.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.4
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• pp.61-68
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• 2002

Thermal shock testing was used to evaluate reliability that appeared in the solder joints of electronic devices when they were subjected to thermal cycling. Recently, mobile devices have come smaller and multi-functional, with the increasing need for high-density packaging, BGA or CSP has become the main trend for surface mounting technology, and therefore mechanical stress life for solder joints in BGA/CSP type packages has required. Reliability of BGA/CSP solder joints was evaluated with electric resistivity change of daisy chain pattern and stress-strain curve measured using strain gage attached on the surface of PCB under mechanical impact loading. In this report, applications of PCB Universal Testing Machine we have developed and experimental datum of SONY estimating dynamic behavior of mechanical stress in BGA/CSP solder joints are introduced.

• Journal of the Korea Furniture Society
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• v.17 no.1
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• pp.1-10
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• 2006

Movement behavior, shrinkage and equilibrium moisture content (EMC), in this experiment reflected a change of hygroscopicity mainly affected by continuously compressive load during radio-frequency/vacuum (RF/V) drying and humidity changes during equilibrating. As a result of interaction of the compressive load and moisture content changing under the RF/V condition, the shrinkages in loading direction were significantly increased while those perpendicular to loading direction were decreased. The shrinkages were affected most in tangential, and least in longitudinal direction. The shrinkages showed higher values in continuous drying than in intermittent drying. In the direction of increased shrinkage, all the movements were also increased, for example, the tangential movement for the loaded-RS and the radial movement for loaded-TS; in the direction of decreased shrinkage, all the movements except the tangential movement for the loaded-TS were decreased such as the tangential and radial movements for the loaded-ES, and the radial movement for the loaded-RS, comparing with those of the load-free. EMCs of the loaded specimens were all higher than that of the load-free specimen, and the highest for the loaded-TS, the lowest for the loaded-ES. The transverse hygroscopicity of specimen was reduced for the loaded-ES, but increased for the loaded-TS.

• Journal of Power Electronics
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• v.18 no.1
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• pp.195-203
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• 2018

In the variable speed Wind Turbine based on ElectroMagnetic Coupler (WT-EMC), a synchronous generator is coupled directly to the grid. Therefore, like conventional power plants, WT-EMC is able to inherently support grid frequency. However, due to the reduced inertia of the synchronous generator, WT-EMC is expected to be controlled to increase its output power in response to a grid frequency drop to support grid frequency. Similar to the grid frequency support control of Type 3 or Type 4 wind turbine, inertial control and droop control can be used to calculate the WT-EMC additional output power reference according to the synchronous generator speed. In this paper, an experimental platform is built to study the grid frequency support from WT-EMC with inertial control and droop control. Two synchronous generators, driven by two induction motors controlled by two converters, are used to emulate the synchronous generators in conventional power plants and in WT-EMCs respectively. The effectiveness of the grid frequency support from WT-EMC with inertial control and droop control responding to a grid frequency drop is validated by experimental results. The selection of the grid frequency support controller and its gain for WT-EMC is analyzed briefly.