• Korean Membrane Journal
• /
• 제11권1호
• /
• pp.21-28
• /
• 2009

We investigated the effect of organic materials on membrane fouling in advanced drinking water treatment by a hybrid module packed with granular activated carbon (GAC) outside multi-channel ceramic microfiltration membrane. Synthetic water was prepared with humic acid and kaolin to simulate natural water resouces consisting of natural organic matter and inorganic particles. Kaolin concentration was fixed at 30 mg/L and humic acid was changed as 2~10 mg/L to inspect the effect of organic matters. Periodic back-flushing using permeate water was performed for 10 sec per filtration of 10 min. As a result, both resistance of membrane fouling (Rf) and permeate flux (J) were influenced highly by concentration of humic acid. It proved that NOM like humic acid could be an important factor on membrane fouling in drinking water treatment. Turbidity and UV254 absorbance were removed up to above 97.4% and 59.2% respectively.

• 설비공학논문집
• /
• 제21권4호
• /
• pp.209-214
• /
• 2009

The purpose of this study is to investigate the effect exchanging water supply on the' rainwater in detached house. It is difficult to decide water supply amount for a closet in detached house, Therefore, to obtain water supply for closet in detached house, it used regression equation using 1,569 data of frequency of used closet and during 120 days. In detached house, the frequency of used closet is 14.6 times/day and water supply amount is $219 {\ell}/day$. The optimum rainwater tank size which is decided by regression equation and using weather data is $8.5\;m^3$. The effect exchanging water supply on the rainwater in detached house is up 50%.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2006년도 하계학술발표대회 논문집
• /
• pp.663-668
• /
• 2006

In the present paper, a single stage fresh water generator was modified and extended to 2 effect desalination system. The inlet temperatures of hot water and feed water were selected as experiment parameters to get operating conditions and fresh water generating rates. The impacts of these parameters on operating conditions and fresh water generating rates were described in detail.

• KSBB Journal
• /
• 제8권1호
• /
• pp.75-82
• /
• 1993

The inhibitory effect of cacao bean husk (CBH) extract on glucosyltransferase(GTasc) from Streptococcus mutans B13 was investigated. Water solube extract from CBH showeda sarong inhibitory effect (88-89%) on GTase from Streptococcus mutans Bl3. GTase inhibitors from sequential extraction by hot water or water-methanol had the strongest inhibition. Sources, fermentation, and types of solvents and fumigation processes did not influence the effect. These active compounds proved to be polyphones through acid hydrolytic analysis of the precipitates by ammonium sulfate or ethanol and proteinase K. It was also confirmed by additional column chromatography of Sephadex G-50, Sephadex LH-20 and DEAE-Sephdex A-50.

• 기술사
• /
• 제45권6호
• /
• pp.54-57
• /
• 2012

Usually the combustion of Bunker-C oil limited in a special area and achieved certain clean air effect. Water added oil combustion has the ability enhance the effect by the Overall Heat Transfer Coefficient. Every water adding step dedicated to reach an increase of the heat transfer effect. So, we can use this system and achieve reasonable energy consumption.

• 대한조선학회논문집
• /
• 제48권6호
• /
• pp.581-591
• /
• 2011

This paper describes the air compressibility effect in the CFD simulation of water impact load prediction. In order to consider the air compressibility effect, two sets of governing equations are employed, namely the incompressible Navier-stokes equations and compressible Navier-Stokes equations that describe general compressible gas flow. In order to describe violent motion of free surface, volume-of-fluid method is utilized. The role of air compressibility is presented by the comparative study of water impact load obtained from two different air models, i.e. the compressible and incompressible air. For both cases, water is considered as incompressible media. Compressible air model shows oscillatory behavior of pressure on the solid surface that may attribute to the air-cushion effect. Incompressible air model showed no such oscillatory behavior in the pressure history. This study also showed that the CFD simulation can capture the formation of air pockets enclosed by water and solid surface, which may be the location where the air compressibility effect is dominant.

• 한국환경보건학회지
• /
• 제23권2호
• /
• pp.24-27
• /
• 1997

This study has been designed to check the removal effect of contaminated water by various water treatmemt processes using sediment filter, activated carbon, reverse osmosis membrane, ultra vilolet sterilizer and ultra filtration and then to analyze the change of pH, the concentration of chlorides, bacteria and E. coli. after 24 hours. pH has increased as much as 0.15-0.32 by activated carbon but decreased sharply by reverse osmosis treatment after 24 hours. The removal effect of chloride was low by activated carbon and ultra filter but high in reverse osmosis. The removal effect of bacteria and E. coli was low by activated carbon and membrane filter system using activated carbon. Ultra filtration process was effective for purify agricultural water containg bacteria and E.coli.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
• /
• pp.883-887
• /
• 1998

Hydration is the main reason for the growth of the material properties. A exact parameter to control the chemical and physical process is not the time, but the degree of hydration. Therefore, it is reasonable that development all material properties should be formulated in terms of degree of hydration. Mathematical formulation of degree of hydration is based on combination of reaction rate functions. The effect of moisture conditions as well as temperature on the rate of reaction is considered in the degree of hydration model. This effect is subdivided into two contributions: water shortage and water distribution. The former is associated with the effect of on the progress of hydration. The water needed for progress of hydration do not exist and there is not enough space for the reaction products to form. The latter is associated with the effect of free capillary water distribution in the pore system. Physically absorption layer does not contribute to progress of hydration and only free water is available for further hydration.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.904-909
• /
• 2008

Most of current slope safety analysis consider only the effect of the rise of underground water level. However, because the infiltration of surface water into the ground is believed to have signification effect on slope stability, the present study performed slope safety analysis in case of the rise of underground water level, infiltration of surface water, and both resulting from rainfall, and examined their effect.

• 상하수도학회지
• /
• 제25권5호
• /
• pp.667-679
• /
• 2011

In this study, the influences of pollutant from Dae-po Stream and So-gam Stream located at the downstream of Nak-dong River on the water quality at Mul-geum water intake station were analyzed using RAMS model. Field measurements of velocity by ADCP, and water quality distribution of BOD and TP by water sampling were carried out to present the input and verification data for numerical simulations. The comparison between RAM2 and ADCP measurement, which aimed for the analysis of 2-D velocity distribution around Mul-geum water intake station showed that two results matched well along the spanwise direction. The prediction of pollutant concentration by RAM4 agreed fairly well with the measured data except for the points nearby right banks in the vicinity of tributary pollutant source. Flushing effect by the increase of mainstream discharge in Nak-dong River was analyzed to provide the damage mitigation in preparation for the accidental water pollution. With increasing mainstream discharge, high velocity and increased water quantity induced increasing dilution effect, thereby decreasing the inflow pollutant concentration rapidly.