• Journal of Navigation and Port Research
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• v.40 no.1
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• pp.1-6
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• 2016

This study was conducted on a circulation system which can recycle waste water from EGCS(Exhaust Gas Cleaning System) using a wet scrubber that is used to treat air pollutants from ships. Though we developed a water treatment system that could remove effectively particulate matters and dispersed oil included in cleaning water for Ship Exhaust Gas Recycle System(DePM & DeSOx), we found that it is difficult to treat minutely dispersed oil only by means of centrifugal-typed purifier. Therefore, to this system, we applied a coalescer that coalesces emulsified minute oil particles in the 2nd phase of dispersion state after being filtered through the centrifugal-typed purifier. After we treated cleaning water drained out of Ship Exhaust Gas Recycle System(DePM & DeSOx) by using both purifier and coalescer, we found that particulate matters and dispersed oil were removed more than 55% and 99%, respectively, in comparison with those contained in cleaning water influent. Putting the results together, we conclude that the treated cleaning water can be recycled as normal cleaning water if this cleaning water treatment system is employed by the wet cleaning tower system for the reduction of air pollutants from ships.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.29-38
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• 1997

In the w/o concentrated emulsion, the volume fraction of the dispersed is greater than 0.74 and the hydrophilic liquid is dispersed in the hydrophobic liquid of the continuous phase. The emulsion has the same appearance and behaviour as a gel. The polarity of the hydrophilic liquids and hydrophobic liquids, the pH and the ionic strength of the hydrophilic liquid are found to be important factors in the stability at the polymerization temperature such as $50^{\circ}C$. The lower the polarity of the hydrophobic liquid and the higher the polarity of the hydrophilic liquid, the more stable the emulsion. Electron microscopy studies of the hydrophilic-hydrophobic polymer composites show that the particles of polyacrylamide, the dispersed phase, are separated by he network of the thin film of polystyrene, the continuous phase. This hydrophilic-hydrophobic polymer composites show higher permselectivity to water in the mixture of water-ethanol. The pervaporation experiment shows that the selectivity of the membrane ranges between 4-40 and increases with increasing enthanol concentration in the feed. The rate of permeation decreases with increasing ethanol concentration in the feed.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.91-98
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• 2010

The effective thermal conductivity of porous materials is usually determined by porosity, water content, and the conductivity of the matrix. In addition, it is also affected by the internal structure of the materials such as the size, arrangement, and connectivity of the matrix-forming grains. Based on the structural models for multi-phase materials, thermal conductivities of soils and sands measured with varying the water content were analyzed. Thermal conductivities of dry samples were likely to fall in the region between the Maxwell-Eucken model with air as the continuous phase and the matrix as the dispersed phase ($ME_{air}$) and the co-continuous (CC) model. However, water-saturated samples moved down to the region between the $ME_{wat}$ model and the series model. The predictive inconsistency of the structural models for dry and water-saturated samples may be caused by the increase of porosity for water-saturated samples, which leads to decrease of connectivity among the grains of matrix. In cases of variably saturated samples with a uniform grain size, the thermal conductivity showed progressive changes of the structural models from the $ME_{air}$ model to the $ME_{wat}$ model depending on the water content. Especially, an abrupt increase found in 0-20% of the water content, showing transition from the $ME_{air}$ model to the CC model, can be attributed to change of water from the dispersed to continuous phase. On the contrary, the undisturbed soil samples with various sizes of grains showed a gradual increase of conductivity during the transition from the $ME_{air}$ model to the CC model.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.4
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• pp.618-623
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• 2004

This paper has dealt with the heat storage characteristics of gel type micro size latent heat storage material slurry. The heat release operation to the gel type micro size latent heat storage material slurry was carried out using hot air bubbles by direct contact heat exchange. This experiment was carried out using phase change material of n-paraffin so the heat release amount is higher than cold water system. The parameters of this experiment were concentration of latent heat phase change material, height of heat release bath and inlet velocity of hot air. The main results obtained are as follows : (1) The effect of concentration of latent heat phase change material dispersed with water is very affective to the direct contact heat exchange between hot air and gel type micro size latent heat storage material slurry. (2) It is clarified that the most effective concentration of latent heat phase change material dispersed with water exists around 20mass% at this type of direct heat exchange model experiment.

• Korean Journal of Materials Research
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• v.17 no.3
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• pp.167-172
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• 2007

The separation of the small colloidal particles from the mixture of two different sized particles using AC dielectrophoresis phenomenon was studied. The spherical mono-dispersed polystyrene particles dispersed in pure water were put into a perfusion chamber on a substrate, and AC electric fold was applied to the glass substrate with Au electrodes in 4 mm distance. The AC frequency was fixed at 1 kHz and the intensity of the field was varied from 25 V/cm to 160 V/cm. After applying the AC field, the degree of the chain formation that resulted from the particle movements by dielectrophoresis was observed by optical microscope. The mixture of the $1\;{\mu}m\;and\;5\;{\mu}m$ sized polystyrene particles at 0.5 vol% concentrations for each size was set in the dielectrophoresis conditions of 1 kHz and 100 V/cm. At this condition large $5\;{\mu}m$ sized polystyrene particles formed chains, on the contrary the $1\;{\mu}m$ sized polystyrene particles formed no chains. After water flowing for 20 min, it was found that small particles that were floating in the chamber had been removed by the water flowing.

• Textile Coloration and Finishing
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• v.26 no.4
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• pp.339-346
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• 2014

To give a positive effect on dispersion behavior of high performance fibers $Vectran^{(R)}$ in water with reference to wet-laid nonwoven technology, 9 kinds of sulfonate type anionic surfactants were chosen to study. After dispersion experiment, the number and the area occupied by fibers in each sample were counted and figured to calculate the index of dispersion in conjunction with quadrat analysis. Similar tendency was observed in the results of two experiments. The sample without addition of any surfactant resulted in the most aggregated dispersion behavior. As the length of alkyl group attached to sulfonate increases, the sample shows more dispersed behavior. The sample with the surfactant having the aryl group and the longer alkyl group shows the most dispersed behavior and it can be seen with the naked eye as well.

• Journal of Dairy Science and Biotechnology
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• v.23 no.2
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• pp.115-123
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• 2005

Microcapsules consisting of natural, biodegradable polymers for controlled and/or sustained core release applications are needed. Physicochemical properties of whey proteins suggest that they may be suitable wall materials in developing such microcapsules. The objectives of the research were to develop water-insoluble, whey protein-based microcapsules containing a model water-soluble drug using a chemical cross-linking agent, glutaraldehyde, and to investigate core release from these capsules at simulated physiological conditions. A model water soluble drug, theophylline, was suspended in whey protein isolate (WPI) solution. The suspension was dispersed in a mixture of dichloromethane and hexane containing 1% biomedical polyurethane. Protein matrices were cross-linked with 7.5-30 ml of glutaraldehyde-saturated toluene (GAST) for 1-3 hr. Microcapsules were harvested, washed, dried and analyzed for core retention, microstructure, and core release in enzyme-free simulated gastric fluid (SGF) and simulated intestinal fluid(SIF) at $37^{\circ}C$. A method consisting of double emulsification and heat gelation was also developed to prepare water-insoluble, whey protein-based microcapsules containing anhydrous milkfat (AMF) as a model apolar core. AMF was emulsified into WPI solution (15${\sim}$30%, pH 4.5-7.2) at a proportion of 25${\sim}$50%(w/w, on dry basis). The oil-in-water emulsion was then added and dispersed into corn oil ($50^{\circ}C$) to form an O/W/O double emulsion and then heated at $85^{\circ}C$ for 20 min for gelation of whey protein wall matrix. Effects of emulsion composition and pH on core retention, microstructure, and water-solubility of microcapsules were determined. Overall results suggest that whey proteins can be used in developing microcapsules for controlled and sustained core release applications.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.185-190
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• 2002

To improve the solubility of poorly water-soluble drug and to develop a sustained release tablets, the need for the technique, the formation of solid dispersion with polymeric materials that can potentially enhance the dissolution rate and extent of drug absorption was considered in this study. The 1:1, 1:4, and 1:5 solid dispersions were prepared by spray drying method using PVP K30, ethanol and methylene chloride. The dissolution test was carried out at in phosphate buffer solution at $37^{\circ}C$ in 100 rpm. Solid dispersed drugs were examined using differential scanning calorimetry and scanning electron microscopy, wherein it was found that felodipine is amorphous in the PVP K30 solid dispersion. Felodifine SR tablets were prepared by direct compressing the powder mixture composed of solid dispersed felodipine, lactose, Eudragit and magnesium stearate using a single punch press. In order to develop a sustained-release preparation containing solid dispersed felodipine, a comparative dissolution study was done using commercially existing product as control. The dissolution rate of intact felodipine, solid dispersed felodipine and its physical mixture, respectively, were compared by the dissolution rates for 30 minutes. The dissolution rates of felodipine for 30 minutes from 1:1, 1:4, 1:5 PVP K30 solid dispersion were 70%, 78% and 90%. However, dissolution rate offelodipine from the physical mixture was 5% of drug for 30 minutes. Our developed product Felodipine SR Tablet showed dissolution of 17%, 50% and 89% for 1, 4, and 7 hours. This designed oral delivery system is easy to manufacture, and drug releases behavior is highly reproducible and offers advantages over the existing commercial product. The dissolution rate of felodipine was significantly enhanced, following the formation of solid dispersion. The solid dispersion technique with water-soluble polymer could be used to develop a solid dispersed felodipine SR tablet.

• Tribology and Lubricants
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• v.35 no.6
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• pp.343-349
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• 2019

According to a report in 2011, hexagonal boron nitride demonstrated good solubility in pure water, even without surfactants or organic functionalization. Hexagonal boron nitride nanosheets are an effective lubricant additive, and their solubility in pure water has motivated lubrication engineers to utilize aqueous solutions containing these nanosheets as water-based lubricants. In this study, we measure the width and height of the hexagonal boron nitride nanosheets dispersed in pure water by using the Zetasizer and atomic force microscopy. Without surfactants or functionalization, aqueous solutions containing 0.10, 0.07, 0.05, and 0.01 wt% of hexagonal boron nitride nanosheets are synthesized via sonication-assisted hydrolysis. The Zetasizer provides only a one-dimensional size of approximately 410 nm, regardless of the concentration of the solution. Thus, it does not allow the estimation of the shape of the nanosheet. To acquire the three-dimensional size of the nanosheets, atomic force microscopy is employed. The aqueous solutions containing 0.10, 0.07, 0.05, and 0.01 wt% of the hexagonal boron nitride nanosheets show average values of 740, 450, 700, and 610 nm in width, and 37, 26, 33, and 32 nm in thickness, respectively. No significant trend is observed between the concentration of the solution and size of the nanosheets. Therefore, when preparing a water-based lubricant, it may be appropriate to adjust conditions such as ultrasonication time rather than the concentration.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1616-1622
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• 2002

If the surfaces of vesicles are chemically modified so that they can be dispersed in organic solvents, the application of vesicular colloids may be expanded. A polymerizable surfactant (BDAC) and nonpolymerizable bipolar surfactant (BPAS) were synthesized in multi-steps. Large vesicles composed of BDAC and BPAS with embedded a cross-linking agent (divinylbenzene) underwent a radical polymerization. BPAS was extracted out using methanol (skeletonization). The headgroup of BDAC was cleaved off via hydrolysis in an acidic condition to yield vesicles where surfaces were covered with -COOH groups. There was no significant change in the overall shape. The skeletonized vesicles appear to have many holes with diameters up to about 25 nm. The holes retained even after hydrolysis. The hydrolyzed vesicles were not dispersed in water and most organic solvents such as tetrahydrofuran and chloroform, but dispersed in methanol.