• 한국염색가공학회지
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• 제26권4호
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• pp.331-338
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• 2014

In this research, split-type complex yarn of 20:80, 40:60, 50:50 nylon6/polyester composition ratio was used in order to impose unique sense on split-type complex woven. After treating both split-type complex yarn of each ratio and its produced woven in alkali solution, we got the following results by checking physical properties based on alkali proportion and treatment time. Under the condition of NaOH 20% in this experiment, it took approximately double time 20% loss of weight. The loss of weight became high when polyester proportion of N/P(nylon6/polyester) composition ratio was low, in the same fineness yarn. Even though polyester proportion was low, the loss of weight was low when the fineness was high. N/P division was well processed at about 25% loss of weight under the condition of NaOH 20%, treatment temperature $50^{\circ}C$, and treatment time 60 minutes. The research provides that the loss of weight should be processed around treatment time 24 hours in the case of NaOH concentration 15%, and treatment time 15 hours in the case of NaOH concentration 18%, respectively, in order to achieve N/P woven division ratio of about 70%-80% in industrial fields.

• 상하수도학회지
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• 제19권5호
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• pp.619-624
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• 2005

This work is for examining a simplified equation based on the rational formula, which can easily decide storm-water detention volume in small urban catchments. The storm-water detention volume is determined by the inflow hydrograph flowing to detention basin and the outflow hydrograph discharged from the detention basin. The ratio of average outflow over the period of rainfall duration against allowable discharge was 0.5 in former simplified equation. But this research has found that the average outflow ratio depends on the storage methodology. In the case of the on-line storage method, the average outflow ratio is a function of the time of concentration of the catchments and rainfall duration, which ranged from 0.5~1.0. In the case of the off-line storage method, the average ratio is a function of peak discharge and allowable discharge except above time of concentration and rainfall duration, where its function value ranged from 1.0~2.0. When applying this equation to small catchment in Mokpo city, South Korea, we could easily calculate the relation curve between the storm-water detention volume and allowable discharge.

• Membrane and Water Treatment
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• 제10권5호
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• pp.361-372
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• 2019

Effect of different alkane based solvents on the stability of emulsion liquid membrane was investigated using normal alkanes (n-hexane, n-heptane, n-octane and n-decane) under various operating parameters of surfactant concentration, emulsification time, internal phase concentration, volume ratio of internal phase to organic phase, volume ratio of emulsion phase to external phase and stirring speed. Results of stability revealed that emulsion liquid membrane containing n-octane as solvent and span-80 (5 % (w/w)) as emulsifying agent presented the highest amount of emulsion stability (the lowest breakage) compared with other solvents; however, operating parameters (surfactant concentration (5% (w/w)), emulsification time (6 min), internal phase concentration (0.05 M), volume ratio of internal phase to organic phase (1/1), volume ratio of emulsion phase to external phase (1/5) and stirring speed (300 rpm)) were also influential on improving the stability (about 0.2% breakage) and on achieving the most stable emulsion. The membrane with the highest stability was employed to extract acridine orange with various concentrations (10, 20 and 40 ppm) from water. The emulsion liquid membrane prepared with n-octane as the best solvent almost removed 99.5% of acridine orange from water. Also, the prepared liquid membrane eliminated completely (100%) other cationic dyes (methylene blue, methyl violet and crystal violet) from water demonstrating the efficacy of prepared emulsion liquid membrane in treatment of dye polluted waters.

• 한국대기환경학회지
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• 제21권1호
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• pp.15-26
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• 2005

An experimental investigation of the gas-phase photooxidation of toluene-NO$_{x}$-air mixtures at sub-ppm concentrations has been carried out in a 6.9 m3, indoor smog chamber irradiated by blacklights. Measured parameters in the toluene-NO$_{x}$ experiments included $O_3$, NO, NO$_2$, NO$_{x}$, CO, SO$_2$ toluene, and air temperature. The initial toluene concentration ranged from 225 ppb to 991 ppb and the initial concentration ratio of toluene/NO$_{x}$ in ppbC/ppb was in the range of 5～20. It was found that the variation of gaseous species with irradiation time caused by the photooxidation of toluene-NO$_{x}$-air mixtures depended on the initial toluene concentration for similar concentration ratio of toluene/NO$_{x}$. The dependency of initial toluene concentration on the photooxidation of toluene-NO$_{x}$-air mixtures for toluene/NO$_{x}$=5～6 seemed to be opposite to that for toluene/NO$_{x}$=10～11. The arriving time at maximum ozone concentration depended on both initial toluene concentration and initial concentration ratio of toluene/NO$_{x}$. However, the maximum concentration of ozone formed by photooxidation depended only on the initial toluene concentration.luene concentration.

• Elastomers and Composites
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• 제33권5호
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• pp.363-369
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• 1998

UV를 이용하여 반응성 모노머인 아크릴아미드를 SBR에 광그라프트 시키는데 있어서 주요한 인자인 모노머 농도, 조사시간 그리고 카본블랙의 함량이 모노머의 그라프트율에 미치는 영향을 살펴보았다. 광개시제로는 benzophenone을 사용하였다. 아크릴아미드의 그라프트율을 측정하기 위하여 FT-IR ATR과 증류수를 이용하여 정접촉각을 측정하였다. 아크릴아미드의 함량과 UV 조사시간이 증가함에 따라 그라프트율은 증가하였으며 또한 접촉각은 감소하는 현상을 나타내었다. SBR중 카본블랙 함량이 증가함에 따라 그라프트율이 증가함을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.373-381
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• 2005

The permeability of contaminated soil and elapsed time are important considering factors to in-situ soil remadiation. Gabr et. al. (1996) derived the solution equation of contaminant concentration ratio as initial one (C/$C_0$) with time and spatial changes in contaminated area which embedded with vertical drains. The contaminant concentration ratio (C/$C_0$) is analyzed with time and spatial changes in three different permeability areas which are $k=l.0{\times}10^{-5,}$ $l.0{\times}l0^{-6,}$ $l.0{\times}l0^{-7}\;_{m/s}$ by using the Gabr's equation. Results from numerical analysis indicate that the ratio (C/$C_0$) decreases as the elapsed time increases in every point, however, remediation efficiency decreases as the analyzing point is far from injection well to extraction one and is deeper from top level of contaminated area. And also it decreases as the permeability of contaminated area decreases. Especially, the lower permeability of contaminated area effects directly on the soil remediation, in this research, under condition which the permeability of contaminated area is $l.0{\times}l0^{-7}\;_{m/s}$, the maximum time needed to attain 90% clean up level ($t_{90}$) is 65,690 hours(7.5 years), it takes so much time to clean the low permeability contaminated soil.

• The Korean Journal of Physiology
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• 제2권2호
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• pp.53-61
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• 1968

Maximal oxygen debt, lactate and excess lactate were measured in 13 men with low hematocrit ratio before and after maximal exercise. Maximal exercise run was performed on a treadmill and the duration of run was 2 minutes 45 seconds in each subject. Hematocrit ratio ranged between 35 and 47%, the mean being 39.8%. The following results were obtained. 1. Maximal oxygen debt expressed on basis of body weight increased as the hematocrit ratio decreased. The correlation coefficient between the two was r= -0.770. 2. The time necessary for decreasing to 50% of total maximal $O_2$ debt(half time) became longer as the hematocrit ratio decreased. In normal men the half time was about 4 minutes and at the longest it was 12 minutes in men with the lowest hematocrit ratio. 3. The lactate concentration reached its peak value after 3 minutes of recovery. Thereafter, the time course of decrease in lactate concentration coincided roughly with that of respiratory oxygen debt curve. To reach to the resting level, however, it took longer time than that of respiratory oxygen debt. 4. Resting concentrations of lactate was 1.28 mM/l, pyruvate 0.13 mM/l and L/P ratio was 9.8. Peak value of ${\Delta}L$ after exercise reached to the value of 10.4 mM/l and ${\Delta}L/P$ reached 26.0. Peak excess lactate after exercise was 6.34 mM/l. 5. The part of oxygen debt accounted for by the oxygen equivalent of excess lactate was only 38.4%. A better relationship between lactate and oxygen debt was observed and the part of oxygen debt accounted for by the oxygen equivalent of lactate was 63.3%. 6. Peak value of lactate after maximal exercise increased as the hematocrit ratio decreased. 7. Respiratory oxygen debt of 100 ml/kg was accounted for by lactate more than 60% and only 30% was by excess lactate. 8. Excess lactate was not a good index of respiratory oxygen debt.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.355-360
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• 2005

The properties of contaminants, contaminated soil, and the elapsed time are important factors to in-situ soil remediation. Gabr et. al. (1996) derived the solution equation of contaminant concentration ratio as initial one $(C/C_0)$ with time and spatial changes in contaminated area with vertical drains. The contaminant concentration ratio $(C/C_0)$ is analyzed with time and spatial changes as varying the effective diameter, porosity, shape factor, density of contaminated soil and temperature in ground and unit weight, viscosity of contaminants by using FLUSH1 model. Results from numerical analysis indicate that the most important factor to the in-situ soil remediation using vertical drains is the effective diameter of contaminated soil. It also shows that the viscosity of contaminants, porosity of soil, shape of soil, temperature in ground, unit weight of contaminants are, in order, affected to the soil remediation but density of soil is insignificant to the soil remediation.

• Environmental Engineering Research
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• 제19권4호
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• pp.395-399
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• 2014

Operation characteristics of the sequencing batch reactor (SBR) process with electro-flotation (EF) as a solid liquid separation method (EF-SBR) were investigated. EF-SBR process showed excellent solid-liquid separation performance which enabled to separate biosolids from liquid phase within 30 min and to extend cyclic reaction time. Although influent organic loading rate was increased stepwise from 5 to 15 g COD/day, food to microorganisms (F/M) ratio could be maintained about 0.3 g COD/g VSS/day in EF-SBR because biomass concentration could be easily controlled at desired level by EF. However, it was impossible to increase biomass concentration at the same level in control SBR (C-SBR) process because solid-liquid separation by gravity settling showed a limitation at higher mixed liquor suspended solids (MLSS) concentration with 60 min of settling time. Total chemical oxygen demand (TCOD) removal efficiency of EF-SBR process was not decreased although influent organic loading rate became 3 times higher than initial value. However, it was seriously deteriorated in C-SBR process after increasing the rate over 10 g COD/day, which was accounted for insufficient organic removal by relatively higher food to microorganisms (F/M) ratio as well as biosolids wash-out by a limitation of gravity sedimentation.

• 한국약용작물학회지
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• 제21권3호
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• pp.174-178
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• 2013

Lime-bordeaux mixture has been used to prevent diseases in the field of ginseng. The purpose of this study is to investigate the efficacy of lime-bordeaux depending on the concentration and treatment time on major diseases of ginseng such as Alternaria blight and anthracnose, and to evaluate the root growth of ginseng. Lime-bordeaux caused damage on leaf when it was sprayed on ginseng between April and early May. No difference was found in root growth by spraying lime-bordeaux mixture between ratio 4-4 and 8-8 ratio in concentration. Plot of 6-6 raito and 8-8 ratio appeared to be similar efficacy compared to that of practical chemical control. However, the plot of 4-4 ratio showed lower than that of chemical control.