• Journal of Korean Society for Atmospheric Environment
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• v.26 no.1
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• pp.77-84
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• 2010

The diffusion and partition coefficients of polyurethane foam (PUF) are estimated using a microbalance experiment and small chamber test. The microbalance is used to measure sorption/desorption kinetics and equilibrium data. When the diffusion condition is controlled in the chamber of the sample, interactions between volatile organic compounds (VOCs) and PUF can lead to the estimation of a relatively homogenous rate of mass transfer in the interiors and surfaces of PUF. The estimates of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) are shown to be independent of the concentrations of VOCs. This approach, if applied to a diffusion-controlled or physically-based model, can facilitate more precise prediction of their source/sink behavior. Although further research and more rigorous validation is needed, an emission model applied with the diffusion and partition coefficients from this research holds promise for the improvement of reliability in predicting the behavior of VOCs emitted from porous building materials by D and K.

• Archives of Pharmacal Research
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• v.14 no.1
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• pp.48-51
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• 1991

Amides from amino acid ester and nalidixic acid were synthesized. The solubility characteristics and partition coefficient of the compounds were studied. The hydrolysis of the compounds was studied in the simulated gastric fluid and simulated intestinal fluid. Some compounds showed better antibacterial activity than nalidixic acid.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.200-209
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• 2003

Distribution coefficient ($K_d$) is an universal parameter estimating cadmium partition for a soil-water-crop system in agricultural lands. This study was performed to find some factors affecting soil-water partition coefficients for cadmium in some Korean soils. The distribution coefficients ($K_d$) of cadmium for the 15 series of agricultural soils were measured at quasi-steady state in the pH ranges from 2 to 11. The adsorption data of the selected soils showed a linear relationship between log $K_d$ and pH, which was well agreed with theoretically expected results ; $log\;K_d=0.6339pH+0.5532(r^2=0.70^{**})$. Normalization of the partition coefficients were performed in a range of pH 3.5 ~ 8.5 to minimize adverse effects of Al dissolution, cationic competition, and organic matter dissolution. The $K_d$-om, partition coefficients normalized for organic matter, improved this linearity to the pH of soils. The values of $K_d$-om measured from the field samples were significantly correlated with those of $K_d$ predicted from the sorption-edge experimental data ($r^2=0.68^{**}$).

• Journal of Environmental Science International
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• v.14 no.9
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• pp.827-835
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• 2005

A three-dimensional ecological model (EMT -3D) was applied to Nonylphenol in Tokyo Bay. EMT -3D was calibrated with data obtained in the study area. The simulated results of dissolved Nonylphenol were in good agreement with the observed values, with a correlation coefficient(R) of 0.7707 and a coefficient of determination (R2) of 0.5940. The results of sensitivity analysis showed that biodegradation rate and bioconcentration factor are most important factors for dissolved Nonylphenol and Nonylphenol in phytoplankton, respectively. In the case of Nonylphenol in particulate organic carbon, biodegradation rate and partition coefficient were important factors. Therefore, the parameters must be carefully considered in the modeling. The mass balance results showed that standing stocks of Nonylphenol in water, in particulate organic carbon and in phytoplankton are $8.60\times 10^5\;g,\;2.19\times 10^2\;g\;and\;3.78\times 10^0\;g$ respectively. With respect to the flux of dissolved Nonylphenol, biodegradation in the water column, effluent to the open sea and partition to particulate organic carbon were $6.02\times10^3\;g/day,\;6.02\times10^2\;g/day\;and\;1.02\times10^1\;g/day$, respectively.

• Journal of Environmental Health Sciences
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• v.34 no.3
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• pp.219-225
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• 2008

Many building materials may contain high concentrations of volatile organic compounds (VOCs) and other hazardous pollutants(HAPs). Specifically, VOCs discharged by indoor building material may cause "new house" syndrome, atopic dermatitis etc. The diffusion coefficient and initially contained total VOC quantity were determined using microbalance experiments and small chamber tests. Interactions between volatile organic compounds (VOCs) and vinyl flooring (VF), a relatively homogenous, diffusion-controlled building material, were characterized. Rapid determination of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) for each VOC was achieved by placing thin VF slabs in a dynamic microbalance and subjecting them to controlled sorption/desorption cycles. K and D are shown to be independent of concentration for all of the VOCs and water vapor. This approach can be applied to other diffusion-controlled materials and should facilitate the prediction of their source/sink behavior using physically-based models.

• Archives of Pharmacal Research
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• v.10 no.2
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• pp.88-93
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• 1987

Chitosan ($\beta$-D-glucosaminan) is chemically prepared from chitin (N-acetyl-$\beta$- D-glucosaminan) which is an unutilized natural resource. We now report on the suitability of the chitosan matrix for use as vehicles for the controlled release of drugs. Salicylic acid and aspirin were used as model drugs in this study. The permeation of salicylic acid in the chitosan membranes was determined in a glass diffusion cell with two compartments of equal volume. Drug release studies on the devices were conducted in a beaker containing 5% sodium hydroxide solution. Partition coefficient (Kd) value for acetate membrane (472) is much greater than that for fluoro-perchlorate chitosan membrane (282). Higher Kd value for acetate chitosan membrane appears to be inconsisstent with the bulk salicylic acid concentration. The permeability constants of fluoro-perchlorate and acetate chisotan membranes for salicylic acid were 3.139 ${\times}10^{-7}cm^2$ min up to 60 min and that of 30% aspirin in the devices was 4.739${\times}10^{-7}cm^2$sec upto 60 min. As the loading dose of aspirin in a chitosan device increased, water up-take of chitosan device increased, but in case of salicylic acid it decreased. The release rate increased with increase in the molecular volume of the drugs. Thses result suggest that the release mechanism may be controlled mainly by diffusion through pores.

• Journal of Environmental Science International
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• v.20 no.4
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• pp.519-525
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• 2011

A three-dimensional ecological model(EMT-3D) was applied to DAS1 in Tokyo Bay. The simulated results of DAS1 were in good agreement with the observed values. The result of sensitivity analysis showed that photolysis coefficient and extinction coefficient were important factor for dissolved DAS1, and photolysis coefficient, extinction and POC partition coefficient for PAHs in particulate organic matter. Mass balance of DAS1 in Tokyo Bay was calculated by using the simulated results of EMT-3D.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.557-564
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• 2000

This study is aimed to develop the adsorbent which can effectively remove toxic hydrophobic organic compounds from the aqueous phase. The emphasis was made to elucidate the adsolubilization behavior of sparingly soluble organic compounds (SSOCs) into the cetyltrimetylammonium bromide(CTAB) layer formed on anthracite by the partition coefficient. The amount of SSOCs removed from aqueous solution was increased with increase of the amount of CTAB coated on the surface and wich increase of SSOCs's hydrophobicity. With the surface-modified solid shown in above. chloroform and benzene at the initial concentration of $6{\times}10^{-4}M$ were removed over 95%. Experimentally determined partition coefficient($K_d$) values between organo-anthracite and organics were 4~25 times higher than theoretical $K_d$ values of same organics Organo-anthracite formed by the addition of the CTAB can effectively immobilize organic contaminants dissolved in landfill leachate and can also be applicable to wastewater treatment containing toxic hydrophobic organic compounds such as chloroform and benzene.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.4
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• pp.259-263
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• 2010

We measured and compared the partition coefficients and absorption levels of preservative phenoxyethanol (PE), antimicrobial ethylhexylglycerin (EG) and UV-filters widely used in cosmetic products and more specifically evaluated the relative absorption level of PE depending on various packaging materials. The resulting partition coefficients of 11 UV filters in relation to PE and EG displayed EG with a relatively higher partition coefficients. The partition coefficients of Tinsorb M and Solaveil CT434 were also high. Among the UV-filter ingredients with EG absorption levels exceeding 40 % were Gransil PSQ, UV Titan M 160 and Micro $TiO_2$ MT 100 TV, whereas Gransil PSQ and Scadder showed PE absorption levels above 40 %. In addition, we confirmed that PE had displayed an absorption level of 7 ~ 8 % as a result of 1 month-long exposure to packaging material polyoxymethylene. This extensive research illustrates the possibility of producing the most potent preservative contents based on studying the relative compatibility between UV-filters and preservatives and selecting the adequate preservatives to be used. Furthermore, preservative level can also decline with passage of time depending on the type of packaging material used.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.237-244
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• 1996

Liquid-liquid extractions by use of microporous hollow fiber modules are fast compared with conventional extraction equipment because of the large surface area per volume. In these modules, the extractant and feed can be contacted at high speed and two flows are completely independent, so there are no problems with loading and channeling. In this paper, it was investigated the extraction selectivities for liquid-liquid extraction of Fe(II) and Ni(II) from dilute aqueous solution into TOA (tri-n-octylamine) and EHPNA (bis(2-ethylhexyle)hydrogenphosphite) as organic extractants by using the hydrophobic hollow fiber module. To determine the rate controlling step for mass transfer in hollow fibers, we also examined the effect of inside and outside flow rates of the hollow fiber module. From these experiments, we identified for the extraction of system with high partition coefficient in hydrophobic hollow fibers, mass transfer in the inside aqueous feed dominated the overall mass transfer, and in this paper, correlation between $K_w$ and $v_t$ was obtained as $K_w{\frac{d}{D}}=6.22\(\frac{d^2v_t}{LD}\)^{1/3}$ On the other hand, for the system with low partition coefficient, the resistance in the inside of hollow fibers was much less than membrane resistance because the extraction was not simple in the micropore. Thus, for systems with high partition coefficients, hydrophobic hollow fibers would be a better choice.