• Title/Summary/Keyword: water-dispersed

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Preparation and Characterization of Solid Dispersion of Ipriflavone with Polyvinylpyrrolidone

  • Jeong, Je-Kyo;Kim, Jung-Hoon;Khang, Gil-Son;Rhee, John M.;Lee, Hai-Bang
    • Journal of Pharmaceutical Investigation
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    • v.32 no.3
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    • pp.173-179
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    • 2002
  • Solid dispersions of ipriflavone with PVP were prepared by a spray-drying method in order to improve the bioavailability. They were measured with scanning electron microscopy, differential scanning calorimetry, x-ray powder diffraction, and Fourier transform infrared spectroscopy to evaluate the physicochemical interaction between ipriflavone and PVP and study the correlation between these physicochemical characteristics and bioavailability. Ipriflavone exhibited crystallinity, whereas PVP was almost amorphous. The area of the endotherm $({\Delta}H)$ of freezer milled ipriflavone, freezer milled ipriflavone physically mixed with freezer milled PVP, and physically mixed ipriflavone with PVP was almost the same, whereas ${\Delta}H$ of the solid dispersed ipriflavone with PVP was much smaller than that of the other preparation types. Also, the crystallinity and the crystal size of ipriflavone in the solid dispersed ipriflavone with PVP were much smaller than those of the other preparation types. From the in vivo test, the AUC of the solid dispersed ipriflavone with PVP was approximately 10 times higher than that of the physically mixed ipriflavone with PVP. The solid dispersion using the spray-drying method with a water-soluble polymer, PVP, may be effective for the improvement of the bioavailability.

Preparation and Properties of Casein graft Carbon black / Polyurethane Composites (Casein 그래프트 카본블랙/폴리우레탄 복합체의 제조와 물성)

  • Lee, Joo-Youb
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.2
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    • pp.463-471
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    • 2018
  • In this study, analyzed of changes resulting from the spread of carbon black in casein grafted water dispersed polyurethane using PPG. For this purpose, casein-grafted water-dispersed polyurethane and (PUD and CPUD's) samples were prepared and samples of CPCB's dispersed with carbon black were prepared. As a result of measuring the tensile strength using prepared samples, the tensile strength was increased to $3.01kgf/mm^2$ with CPUD3, which contains highly casein, in CPCB's tensile strength was measured as low as $2.54kgf/mm^2$ with increasing carbon black. Elongation was measured in 278% of PUD samples containing less casein, and CP3CB4 in CPCB's was measured as 157%. The abrasion resistance of the samples was 36.97 mg.loss for CPUD3 and 41.11 mg.loss for CP3CB4. The solvent resistance of the PUD 's sample and the CPCB' s sample were not changed.

A Study on the Evaluation of Basic Properties of Composite Emulsion Finishes (복합 에멀젼계 마감재의 기초물성 평가에 관한 연구)

  • Ryu, Hwa-Sung;Shin, Sang-Heon;Kim, Deuck-Mo;Song, Sung-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.20 no.1
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    • pp.35-41
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    • 2020
  • The thin coating material used in the outer insulation finishing method is a finishing material mainly based on acrylic emulsion. In this study, the properties of silane modified acrylic emulsion and silica dispersed acrylic emulsion were evaluated. Experimental results showed that the silane modified acrylic emulsion had no significant effect on improving tensile strength, but was effective in improving the performance of adhesion strength, water absorption coefficient, and hot and cold repeat resistance. Silica-dispersed acrylic emulsions were effective in improving tensile strength, and at 10% substitution rate, they were effective in improving the performance of adhesion strength, water absorption coefficient and hot / cold resistance. Through this, it was judged that a composite emulsion capable of improving the performance of the acrylic emulsion could be prepared.

A Comparative Study on the Thermal Conductivities and Viscosities of the Pure Water and Ethanol Carbon Nanofluids (순수 물과 에탄올 산화 탄소나노유체의 열전도도 및 점도 특성 비교 연구)

  • An, Eoung-Jiw;Park, Sung-Seek;Chun, Won-Gee;Park, Yoon-Chul;Jeon, Youn-Han;Kim, Nam-Jin
    • Journal of the Korean Solar Energy Society
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    • v.32 no.spc3
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    • pp.213-219
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    • 2012
  • Nanofluids are advanced concept fluid that solid particles of nanometer size are stably dispersed in fluid likes water, ethylene glycol and others. They have higher thermal conductivities than base fluids. If using this characteristic, efficiencies of heat exchangers can be increased. Therefore in this study, we measured thermal conductivity and viscosity of carbon nanofluids. They were made to ultra sonic dispersed oxidized multi-walled carbon nanotubes(OMWCNTs) in distilled water and ethanol, respectively. The mixture ratios of OMWCNTs were from 0.0005 vol% ~ 0.1 vol%. Thermal conductivity and viscosity was measured by transient hot-wire method and rotational viscometer. The results of an experiment are as in the following: thermal conductivity of the 0.1 vol% pure-water nanofluid improved 7.98% ($10^{\circ}C$), 8.34% ($25^{\circ}C$), and 9.14% ($70^{\circ}C$), and its viscosity increased by 37.08% ($10^{\circ}C$), 33.96% ($25^{\circ}C$) and 21.64% ($70^{\circ}C$) than the base fluids. Thermal conductivity of the 0.1 vol% ethanol nanofluids improved 33.72% ($10^{\circ}C$), 33.14% ($25^{\circ}C$), and 32.25% ($70^{\circ}C$), and its viscosity increased by 35.12% ($10^{\circ}C$), 32.01% ($25^{\circ}C$) and 19.12% ($70^{\circ}C$) than the base fluids.

Energy Harvesting System according to Moisture Absorption of Textile and Efficient Coating Method as a Carbon Black (섬유 고분자의 수분 흡수에 따른 에너지 하베스팅 발전 소자 및 이를 위한 카본 블랙의 효율적인 코팅법)

  • Choi, Seungjin;Chae, Juwon;Lee, Sangoh;Lee, Jaewoong
    • Textile Coloration and Finishing
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    • v.33 no.4
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    • pp.280-287
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    • 2021
  • Generating electricity by using water in many energy harvesting system is due to their simplicity, sustainability and eco-friendliness. Evaporation-driven moist-electric generators (EMEGs) are an emergent technology and show great potential for harvesting clean energy. In this study, we report a transpiration driven electro kinetic power generator (TEPG) that utilize capillary flow of water in an asymmetrically wetted cotton fabric coated with carbon black. When water droplets encounter this textile EMEG, the water flows spontaneously under capillary action without requiring an external power supply. First carbon black sonicated and dispersed well in three different solvent system such as dimethylformamide (DMF), sodiumdedecylbenzenesulfonate (SDBS-anionic surfactant) and cetyltrimethylammoniumbromide (CTAB-cationic surfactant). A knitted cotton/PET fabric was coated with carbon black by conventional pad method. Cotton/PET fabrics were immersed and stuttered well in these three different systems and then transferred to an autoclave at 120 ℃ for 15 minutes. Cotton/PET fabric treated with carbon black dispersed in DMF solvent generated maximum current up to 5 µA on a small piece of sample (2 µL/min of water can induce constant electric output for more than 286 hours). This study is high value for designing of electric generator to harvest clean energy constantly.

Rheological Study on bentonite Clay Sedimentation with various concentrations of Sea water (해수의 농도 변화에 따른 bentonite 침전에 대한 유변학적 고찰)

  • 최상원;서호준
    • Journal of Environmental Science International
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    • v.5 no.1
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    • pp.35-41
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    • 1996
  • For studying of coagulation and sedimentation in estuarine clay, we obtained several flow curves with various concentrations of sea water by using Coutte type rotational rheometer. The initial shear stress on high concentration of sea water was observed big, but after this, its value is decreasing with increasing shear rate. The maximum pick of shear stress is decreasing with the decreasing of concentration of sea water The trend is same totally above for viscosity. The sedimentation times with the concentration of sea water vary in $\infty$ ~ 5 minutes. The zeta potential is changed dramatically between 114 and 118 concentration of sea water. That is consistent with the sedimentation graph. From these results, the phenomena of coagulation and sedimentation can be explained with viscoelastic terms on structual formation among particles by the changes of surface potential affected from contacting sea water to dispersed particles.

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Size sorting of chemically modified graphene nanoplatelets

  • Han, Joong Tark;Jang, Jeong In;Kim, Sung Hun;Jeong, Seung Yol;Jeong, Hee Jin;Lee, Geon-Woong
    • Carbon letters
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    • v.14 no.2
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    • pp.89-93
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    • 2013
  • Size-sorted graphene nanoplatelets are highly desired for fundamental research and technological applications of graphene. Here we show a facile approach for fabricating size-sorted graphene oxide (GO) nanoplatelets by a simple centrifugal method using different dispersion solvents. We found that the small-sized GO nanoplatelets were more effectively separated when dispersed in water or dimethylformamide (DMF) than in an alkali aqueous solution. After several iterations of the centrifugation, the sizes of GO in the supernatant solution were mostly several micrometers. We found that the GO area was not strongly correlated with the C-O content of the GO dispersed in water. However, the size-sorted GO nanoplatelets in DMF showed different C-O content, since DMF can reduce GO nanoplatelets during exfoliation and centrifugation processes.

Removal of Inorganic Odorous Compounds by Scrubbing Techniques using Silver Nano-particles (나노 은 입자 세정법을 이용한 무기 악취물질의 제거)

  • Shin, Seung-Kyu;Huyen, Tran;Song, Ji-Hyeon
    • Journal of Korean Society for Atmospheric Environment
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    • v.24 no.6
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    • pp.674-681
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    • 2008
  • Silver as a metal catalyst has been used to remove odorous compounds. In this study, silver particles in nano sizes ($5{\sim}30nm$) were prepared on the surface of $NaHCO_3$, the supporting material, using a sputtering method. The silver nano-particles were dispersed by dissolving $Ag-NaHCO_3$ into water, and the dispersed silver nano-particles in the aqueous phase was applied to remove inorganic odor compounds, $NH_3$ and ${H_2}O$, in a scrubbing reactor. Since ammonia has high solubility, it was removed from the gas phase even by spraying water in the scrubber. However, the concentration of nitrate (${NO_3}^-$) ion increased only in the silver nano-particle solution, implying that the silver nano-particles oxidized ammonia. Hydrogen sulfide in the gas phase was rapidly removed by the silver nano-particles, and the concentration of sulfate (${SO_4}^{2-}$) ion increased with time due to the oxidation reaction by silver. As a result, the silver nano-particles in the aqueous solution can be successfully applied to remove odorous compounds without adding additional energy sources and producing any harmful byproducts.

Flow Characteristics in a Particle/Bubble Motion with Hybride PIV (Hybride PIV에 의한 단일입자/기포운동에 관한 연구)

  • Choi, Hae-Man;Terauchi, T.;Monji, H.;Matsui, G.
    • The KSFM Journal of Fluid Machinery
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    • v.5 no.1 s.14
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    • pp.7-12
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    • 2002
  • As the first step to investigate the fundamental mechanism of a dispersed two-phase flow, we studied the detailed interactions between bubble or particle motion and flow around it. Experiments were carried out with a rising bubble or particle in stagnant water in a vertical pipe. Particles with different densities, and/or different shapes were used for comparison with a bubble. We adopted 3D-PTV (Three-Dimensional Particle Tracking Velocimetry) for measuring the bubble or particle motions, and PIV (Particle Image Velocimetry) for measuring the water flow simultaneously (Hybrid PIV). The experimental results showed that the oblate spheroidal solid particle rose along the longer axis direction at the point that the inclination of the longer axis reached the maximum, and the inclination direction changed after moving. The bubble moved to the direction that the spheroid's projected width grew up to the largest, and the minor axis of the oblate spheroidal body of the bubble was parallel to the moving direction. The trajectory of the center of the particle/bubble which was measured with 3D-PTV, was marked on the section (x-y) of the pipe. It exhibited the pattern of the particle/bubble motion.

Preparation of Resveratrol-loaded Poly($\varepsilon$-caprolactone) Nanoparticles by Oil-in-water Emulsion Solvent Evaporation Method

  • Kim, Bum-Keun;Lee, Jun-Soo;Oh, Ju-Kyoung;Park, Dong-June
    • Food Science and Biotechnology
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    • v.18 no.1
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    • pp.157-161
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    • 2009
  • Resveratrol-loaded poly($\varepsilon$-caprolactone) (PCL) nanoparticles were prepared by oil in water (O/W) emulsion solvent evaporation method. The morphology of the nanoparticles was evaluated using atomic force microscope (AFM), in which well-shaped and rigid nanoparticles were prepared. The mean particle size of nanoparticles prepared using only dichloromethane (DCM) ($523.5{\pm}36.7\;nm$) was larger than that prepared with a mixture of DCM and either ethanol (EtOH) ($494.5{\pm}29.2\;nm$) or acetone ($493.5{\pm}6.9\;nm$). The encapsulation efficiency of nanoparticles prepared only with DCM as dispersed phase ($78.3{\pm}7.7%$) was the highest of those prepared with solvent mixtures. An increase in the molecular weight of PCL led to an increase in encapsulation efficiency (from $78.3{\pm}7.7$ to $91.4{\pm}3.2%$). Pluronic F-127 produced the smallest mean size ($523.5{\pm}36.7\;nm$) with the narrowest particle size distribution. These results show that dispersed phase, molecular weight of wall materials, emulsion stabilizer could be important factors to affect the properties of nanoparticles.