• Title/Summary/Keyword: surface zeta-potential

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Improving the Quality of Response Surface Analysis of an Experiment for Coffee-supplemented Milk Beverage: II. Heterogeneous Third-order Models and Multi-response Optimization

  • Rheem, Sungsue;Rheem, Insoo;Oh, Sejong
    • Food Science of Animal Resources
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    • v.39 no.2
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    • pp.222-228
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    • 2019
  • This research was motivated by our encounter with the situation where an optimization was done based on statistically non-significant models having poor fits. Such a situation took place in a research to optimize manufacturing conditions for improving storage stability of coffee-supplemented milk beverage by using response surface methodology, where two responses are $Y_1$=particle size and $Y_2$=zeta-potential, two factors are $F_1$=speed of primary homogenization (rpm) and $F_2$=concentration of emulsifier (%), and the optimization objective is to simultaneously minimize $Y_1$ and maximize $Y_2$. For response surface analysis, practically, the second-order polynomial model is almost solely used. But, there exists the cases in which the second-order model fails to provide a good fit, to which remedies are seldom known to researchers. Thus, as an alternative to a failed second-order model, we present the heterogeneous third-order model, which can be used when the experimental plan is a two-factor central composite design having -1, 0, and 1 as the coded levels of factors. And, for multi-response optimization, we suggest a modified desirability function technique. Using these two methods, we have obtained statistical models with improved fits and multi-response optimization results with the predictions better than those in the previous research. Our predicted optimum combination of conditions is ($F_1$, $F_2$)=(5,000, 0.295), which is different from the previous combination. This research is expected to help improve the quality of response surface analysis in experimental sciences including food science of animal resources.

Mobility of silver nanoparticles (AgNPs) and oxidative degradation of endocrine disrupting chemicals by saturated column experiments (포화컬럼실험에서 산화공정을 적용한 내분비계 장애물질의 제거 및 은나노물질의 거동 연구)

  • Kim, Yejin;Heo, Jiyong
    • Journal of Korean Society of Water and Wastewater
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    • v.32 no.6
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    • pp.499-505
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    • 2018
  • We applied column experiments to investigate the environmental fate and transport of silver nanoparticles(AgNPs) in fully saturated conditions of porous media. These column experiments were performed to emphasize oxidation method with $H_2O_2$ concentration and acidic conditions. The mobility of AgNPs was decreased with the increasing ionic strength that the surface charge of AgNPs(zeta potential) was neutralized with the presence of positive ions of $Na^+$. Additionally, it was also affected due to that not only more increased aggregated size of AgNPs and surface charge of quartz sand. The decreased breakthrough curves(BTCs) of bisphenol-A(BPA) and $17{\alpha}$-ethynylestradiol(EE2) were removed approximately 35.3 and 40%. This is due to that endocrine disrupting chemicals(EDCs) were removed with the release of $OH{\cdot}$ radicals by the fenton-like mechanisms from acidic and fenton-like reagent presenting. This results considered that higher input AgNPs with acidic conditions is proved to realistic in-situ oxidation method. Overall, it should be emphasized that a set of column experiments employed with adjusting pH and $H_2O_2$ concentration in proved to be effective method having potential ability of in-situ degradation for removing organic contaminants such as BPA and EE2.

Enhanced nucleation density by heat treatment of nanodiamond seed particles (나노다이아몬드 seed 입자의 열처리에 의한 핵형성 밀도 향상)

  • Park, Jong Cheon;Jeong, Ok Geun;Son, Bit Na;Cho, Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.23 no.6
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    • pp.291-295
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    • 2013
  • Surface chemical modification via air and hydrogen heat treatment was found to relieve the aggregation of nanodiamond (ND) seed particles and lead to a significantly enhanced nucleation density for ultrananocrystalline diamond (UNCD) film growth. After heat treatment in air and hydrogen, modification of surface functionalities and increase in the zeta potential were observed. Mean size of the ND aggregates was also dramatically reduced from ${\sim}2{\mu}m$ to ~55 nm. Si surface seeded with ND particles heat-treated at $600^{\circ}C$ in hydrogen produced a much higher nucleation density of ${\sim}2.7{\times}10^{11}cm^{-2}$ compared to untreated ND seeds.

Pressureless Infiltration Processing of B4C/Al Composite by Surface Modification (표면 개질에 의한 상압에서의 B4C/Al복합체 제조 방법)

  • 임경란;강덕일;김창삼
    • Journal of the Korean Ceramic Society
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    • v.40 no.2
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    • pp.128-131
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    • 2003
  • Formation of$B_4C/Al$composite by pressureless infiltration was investigated by lowering wetting angle via surface modification of $B_4C$powder with alumina precursor. Surface modification was confirmed by zeta potential analysis. The$B_4C/Al$composite was prepared by placing an Al 6061 disk on the$B_4C$preform and heating at $1030{\circ}C$/20 min under a flowing argon, but no infiltration took place for a bare $B_4C$ preform even at$1250{\circ}C$/30 min. Analysis of XRD and SEM showed the $Al_3BC$phase besides$B_4C$and Al, but no trace of deteriorative$A1_4C_3$.

Dispersion Characteristics of α-Fe2O3 Nanopowders Coated with Titanium Dioxide by Atomic Layer Deposition

  • Ok, Hae Ryul;Lee, Bo Kyung;Bae, Hye Jin;Kim, Hyug Jong;Choi, Byung Ho
    • Journal of the Korean Ceramic Society
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    • v.54 no.2
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    • pp.137-140
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    • 2017
  • A $TiO_2$ nanofilm was deposited on ${\alpha}-Fe_2O_3$ nanopowders using the atomic layer deposition method. The $TiO_2$ film was prepared at $300^{\circ}C$ using $Ti(N(CH_3)_2)_4$ and $H_2O$ as the precursor and reactant gas, respectively. The thickness and composition of the $TiO_2$ surface were characterized by TEM and EDS measurements. The TEM results showed that the growth rate of the film was about $0.12{\AA}/cycle$. The EDS and SAED analyses showed the presence of titanium oxide on the surface of the ${\alpha}-Fe_2O_3$ nanopowders, confirming the deposition of the $TiO_2$ nanofilm. The Zeta potential and sedimentation test results showed that the dispersibility of the coated nanopowders was higher than that of the uncoated nanopowders. This is attributed to the electrostatic repulsion between the $TiO_2$-coated layers on the surface of the ${\alpha}-Fe_2O_3$ nanopowders. The results revealed that the $TiO_2$-coated layers modified the surface characteristics of the ${\alpha}-Fe_2O_3$ nanopowders and improved their dispersibility.

Properties of Poly(acrylic acid) Hydrogel by the Surface Charge of Magnetite Nanoparticles (나노 자철광의 표면전하에 따른 Poly(acrylic acid) 수화젤의 물성)

  • Seo Dong-Pil;Kang Hwi-Won;Jeong Chang-Nam
    • Polymer(Korea)
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    • v.30 no.5
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    • pp.412-416
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    • 2006
  • The superparamagnetic nanoparticles were prepared by coprecipitation of $FeCl_3$ and $Na_2SO_3$ with $NH_4OH$ and the surface charge on hydroxyl group by chemisorption was changed depending on pH. We studied correlation between surface charge of magnetite and pH. Using this correlation the properties of poly (acrylic acid) (PAAc) hydrogel embedded with magnetite was studied. The magnetite was characterized by XRD, AFM. and FTIR. The zeta-potential of magnetite was influenced by pH: great positive charge was shown high under the pH 4 and isoelectric point was found at pH 7. The hydrogen bond formed by combining oi PAAc hydrogel and magnetic colloid under pH 4 caused tensile strength to increase, while swelling and elongation at break to decrease. The result confirmed that the magnetic moment was increased proportionally to the content of magnetite.

Enhancing Transfection Efficiency Using Polyethylene Glycol Grafted Polyethylenimine and Fusogenic Peptide

  • Lee, Haeshin;Jeong, Ji-Hoon;Lee, Je-Hoon;Park, Tae-Gwan
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.6 no.4
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    • pp.269-273
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    • 2001
  • This study presents a new formulation method for improving DNA transfection effi-ciency using a fusogenic peptide and polyethylene glycol-grafted polyethylenimine. Succinimidyls succinate polyethylene glycol (PEG-SSA) was conjugated with polyethylenimine(PEL). PEL is well known for a good endosomal escaping and DNA condensign agent. The positively charged syn-thetic fusogenic peptide, KALA was coated on the negatively charged PEG-g-PEI/DNA and PEI/DNA complexes. The KALA/PEI/ DNA complexes exhibited aggregation behavior at higher KALA coating amount with an effective diameter of around 1,000 nm. However, the LALA/PEG-g-PEI/DNA complexes were 100-300 nm in size with a surface zeta-potential (ζ)value of about +20mV. The conjugated PEG molecules suppressed any KALA-mediated inter-particle aggregation, and thereby improved the transfection efficiency, Consequently, the transfection efficiency of the KALA/PEG-g-PEI/DNA complexes was obtained by utilizing both the fusogenic activity of KALA and the steric repulsion effect of PEC.

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Polishing Properties by Change of Slurry Temperature in Oxide CMP (산화막 CMP 공정에서 슬러리 온도 변화에 따른 연마 특성)

  • Ko, Pil-Ju;Park, Sung-Woo;Kim, Nam-Hoon;Seo, Yong-Jin;Lee, Woo-Sun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.3
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    • pp.219-225
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    • 2005
  • To investigate the effects of slurry temperature on the chemical mechanical polishing(CMP) performance of oxide film with silica and ceria slurries, we have studied slurry properties as a function of different slurry temperature. Also, the effects of each input parameter of slurry on the oxide CMP characteristics were investigated. The pH showed a slight tendency of decrease, the conductivity in slurries showed an increased tendency, the mean particle size in slurry decreased, and the zeta potential of slurry decreased with temperature. The removal rates significantly increased and maintained at the specific levels over 4$0^{\circ}C$. The better surface morphology of oxide films could be obtained at 40 $^{\circ}C$ of silica slurry and at 90 $^{\circ}C$ of ceria slurry. It is found that the CMP performance of oxide film could be significantly improved or controlled by change of slurry temperature.

Adsorption of cationic birchwood xylan on Hw-BKP and its effect on paper properties (양이온성 자일란의 Hw-BKP에의 흡착특성과 이에 따른 종이 물성 변화)

  • Lee, Sang-Hoon;Lee, Hak-Lae;Youn, Hye-Jung;Xiang, Zhu Hong
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.42 no.2
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    • pp.1-11
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    • 2010
  • The possibility of applying birchwood xylan in papermaking process to improve dry strength of paper was investigated. Unmodified xylan barely adsorbed onto pulp fibers while cationically modified xylan adsorbed substantially. Adsorption of cationically modified xylan by quaternarization with 3-chloro-2-hydroxypropy trimethylammonium chloride improved dry strength of paper. Chemical structure and degree of substitution of the cationically modified xylan was determined by 400 MHz 13CNMR spectroscopy and elemental analyzer. The amount of adsorbed xylan on cellulose fibers was greater when the cationicity was moderate, and it was interpreted that the conformation of this cationic xylan adsorbed on fiber surface was more favorable for greater adsorption due to its greater loop formation tendency while highly cationic xylan tends to adsorbed in stretched conformation. The physical properties of handsheets increased as the amount of adsorbed cationic xylan increased. On the other hands, the optical properties decreased with xylan adsorption.

Separation of Silicon and Silica by Liquid-Liquid Extraction

  • Fujita, Toyohisa;Oo, Kyaw-Zin;Shibayama, Atsushi;Miyazaki, Toshio;Kuzuno, Eiichi;Yen, Wan-Tai
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.719-724
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    • 2001
  • The objective of this investigation was to separate silicon and silica for recycling by the liquid-liquid separation technique. In the preparation of silicon (Si) single crystal, a small amount of silicon is fixed on the surface of silica (quartz, $SiO_2$) crucible. The used crucible is crushed for recycling both silicon and silica in a high purity from the mixed powder. Zeta-potential of silicon and silica are almost the same at pH higher than 3. Their separation by simple flotation is ruled out. However, their hydrophobic characteristics are different in several different organic solvent from the measurement of contact angle. Therefore, the liquid-liquid extraction is employed to separate silicon and silica. The result indicates that the organic solvent mixed with dodecyl ammonium acetate could extracted the silicon powder at high purity (97-100%) with high recovery from the silica powder in the water phase.

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