• Title/Summary/Keyword: Property of dilute solution

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Migration in concentrated suspension of spherical particles dispersed in polymer solution

  • Kim, Chongyoup
    • Korea-Australia Rheology Journal
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    • v.13 no.1
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    • pp.19-27
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    • 2001
  • In this symposium paper, the migration and hydrodynamic diffusion of non-colloidal, spherical particles suspended in polymer solutions are considered under Poiseuille or torsional flows. The migration phenomena in polymer solutions are compared with those in Newtonian fluids and the effect of fluid elasticity is discussed. The experimental results on particle migration in dilute polymer solution reveal that even a slight change in the rheological property of the dispersing medium can induce drastic differences in flow behavior and migration of particles, especially in dilute and semi-concentrated suspensions.

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Dilute Solution Properties of Biopolymer Produced by Alkali-Tolerant Bacillus sp. (알칼리 내성 Bacillus Sp.에 의한 생물 고분자의 희석용액 특성)

  • Lee, Shin-Young;Kim, Jin-Young
    • Journal of Industrial Technology
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    • v.20 no.A
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    • pp.39-44
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    • 2000
  • Highly viscous biopolymer from alkali-tolerant Bacillus sp. was purified and its solution properties were investigated. The intrinsic viscosities for crude biopolymer and biopolymers purified by dialysis or CPC(cetylpyridinium chloride) treatment were 58.24, 73.60 and 42.18 dL/g, respectively. The intrinsic viscosity of biopolymer showed the maximum value at the neutral pH but it was decreased remarkably at the alkaline or acidic pH. Biopolymer exhibited the property of polyelectrolyte, showing the sharp decrease of intrinsic viscosity by the addition of NaCl. Intrinsic viscosity of dilute solution at the low NaCl concentration was exponentially dependent on temperature and its temperature dependency was increased with NaCl concentrations. The chain stiffness, coil overlap parameter, and critical concentration were 0.09, 5.25 and 0.07g/dL, respectively. Temperature dependency on intrinsic viscosity of biopolymer solution was different each other at $45^{\circ}C$. Flow activation energies at temperatures above $45^{\circ}C$ were constant, while those at temperatures below $45^{\circ}C$ increased with increase of added NaCl concentration.

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Property of Poly(amic acid) Precursor Solution (Poly(amic acid) 전구체 용액의 성질)

  • Ahn, Young Moo
    • Textile Coloration and Finishing
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    • v.8 no.2
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    • pp.43-48
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    • 1996
  • Condensation type aromatic polyimides were synthesized in DMF solvent by two step low temperature solution polymerization. By employing monomers as p-phenylene 3diamine and 3 kinds of dianhydrides such as pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride and trimellitic anhydride chloride, poly(amic acid) precursors were sythesized. These reactions were exothermic and very fast. When synthesized poly(amic acid)s were dissolved in DMF solvent and stood long time, the polymers were hydrolyzed and their degradation reactions were accelerated as the solution concentrations were dilute. Also, when water is added there-to the degradation rates were accelerated 8faster. In addition, in a very dilute solution state, the reduction viscosity is greatly increased to show properties of conventional polyelectrolytes. This also showed properties sensitive to the concentration change as carboxyl groups per unit segment are increased.

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Solution Properties of ${\gamma}$-Polyglutamic Acid Produced by Alkalophilic Alcaligenes sp. (호 알칼리성 Alcaligenes sp.가 생산하는 ${\gamma}$-Polyglutamic Acid의 용액 특성)

  • 이신영;강태수김갑수
    • KSBB Journal
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    • v.10 no.4
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    • pp.386-392
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    • 1995
  • The high viscous ${\gamma}$-polyglutamic acid(${\gamma}$-PGA) from alkalophilic Alcaligenes sp. was purified and its solution property was investigated. The intrinsic viscosities for Na+ form and H+ form of ${\gamma}$-PGA were 31.1 and 0.38d$\ell$/g, respectively. The viscosity of H+-PGA was not influenced by pH or salts while that of Na+-PGA was influenced. The intrinsic viscosity of Na+-PGA solution decreased remarkably at the alkaline or acidic pH and showed the sharp decrease when salts were added. ${\gamma}$-PGA exhibited the property of the polyelectrolyte showing the .sharp decrease of intrinsic viscosity by the addition of NaCl, and intrinsic viscosity of dilute solution with the low concentration of NaCl was exponentially dependent on temperature and its temperature dependency increased with increasing NaCl concentration. The chain stiffness, coil overlap parameter and critical concentration of Na+-PGA were 0.08, 5.25 and 0.07g/d$\ell$, respectively.

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An Analysis of Textbook Contents and Survey of Chemistry Major Teachers' Thinking Types Related to Dilute Solutions Properties (묽은 용액의 성질에 대한 교과서 내용 분석 및 화학전공교사의 사고유형 조사)

  • Kim, Seong-Hye;Lee, Eun-Sil;Paik, Seong-Hey
    • Journal of The Korean Association For Science Education
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    • v.28 no.4
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    • pp.291-301
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    • 2008
  • The purpose of this study was to investigate explanations of high school chemistry II textbooks and the diversity of chemistry major teachers' thinking types related to dilute solution properties for finding the sources of students' difficulties. Eight kinds of textbooks were analyzed, and the teachers' thoughts were searched by a questionnaire developed for inquiring teachers' preference of explanation types. We analyzed teachers' responses from individual interviews after the questionnaire to discern their deeper thoughts. From the results, it was found that the explanations of the textbooks were not clear enough to have scientific conceptions. The figures and explanations of the textbooks do not match either. It was also found that chemistry major teachers' thoughts were not solid when they suffered cognitive confliction by different situation with their thoughts.

A Case Study of Chemistry Major Pre-service Teacher's Understanding about the Properties of Dilute Solutions and Perception on Teacher Education Curriculum (묽은 용액의 성질에 대한 화학전공 예비교사들의 이해 및 화학교사 양성교육에 대한 인식 사례 연구)

  • Lee, Song-Yeon;Kim, Soeng-Hye;Paik, Seoung-Hey
    • Journal of the Korean Chemical Society
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    • v.54 no.6
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    • pp.787-798
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    • 2010
  • We compared the understanding of 4 pre-service teachers of chemistry education major and 2 pre-service teachers of chemistry major related to conceptions of "properties of dilute solutions" chapter in high school Chemistry II textbooks. As results, few pre-service teachers understood fully the concepts of high school Chemistry II textbooks. Some pre-service teachers had misconceptions related to properties of dilute solutions. We found that few differences existed between the pre-service teachers' understanding regardless of whether they took a major in chemistry education of a education college or a major in chemistry of noneducation college. Most of the pre-service teachers who attended this research recognized the lack of practical knowledge in their pre-service teacher curriculum.

Choline chloride-Glycerol (1:2 mol) as draw solution in forward osmosis for dewatering purpose

  • Dutta, Supritam;Dave, Pragnesh;Nath, Kaushik
    • Membrane and Water Treatment
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    • v.13 no.2
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    • pp.63-72
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    • 2022
  • Choline chloride-glycerol (1:2 mol), a natural deep eutectic solvent (NADES) is examined as a draw solution in forward osmosis (FO) for dewatering application. The NADES is easy to prepare, low in toxicity and environmentally benign. A polyamide thin film composite membrane was used. Characterization of the membrane confirmed porous membrane structure with good hydrophilicity and a low structural parameter (722 ㎛) suitable for FO application. A dilute solution of 20% (v/v) NADES was enough to generate moderate water flux (14.98 L m-2h-1) with relatively low reverse solute flux (0.125 g m-2h-1) with deionized water feed. Application in dewatering industrial wastewater feed showed reasonably good water flux (11.9 L m-2h-1) which could be maintained by controlling the external concentration polarization and fouling/scaling mitigation via simple periodic deionized water wash. In another application, clarified sugarcane juice could be successfully concentrated. Recovery of the draw solute was accomplished easily by chilling utilizing thermo responsive phase transition property of NADES. This study established that low concentration NADES can be a viable alternative as a draw solute for dewatering of wastewater and other heat sensitive applications along with a simple recovery process.

Synthesis of AlO(OH) Nano Colloids from γ-Al2O3 via Reversible Process (γ-Al2O3로부터 가역과정을 경유한 AlO(OH) 나노콜로이드의 합성)

  • Cho, Hyun-Ran;Kim, Sook-Hyun;Park, Byung-Ki
    • Journal of the Korean Ceramic Society
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    • v.46 no.3
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    • pp.288-294
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    • 2009
  • The platelet AlO(OH) nano colloids were prepared by hydrothermal reaction of the $\gamma-Al_2O_3$ obtained with dehydration of $\gamma$-AlO(OH) and dilute $CH_3COOH$ solution. In hydrothermal reaction process, reversible reaction was accompanied between $\gamma-Al_2O_3$ and AlO(OH), and hydrothermal reaction temperature, hydrothermal reaction time and $CH_3COOH$ concentration had an effect on the crystal structure, surface chemical property, surface area, pore characteristics and crystal morphology of the AlO(OH) nano colloid particles. In this study, it was investigated to the hydrothermal reaction condition of the AlO(OH) nano colloid for using catalyst support, heat resisting agent, adsorbents, binder, polishing agent and coating agent. The crystal structure, surface area, pore volume and pore size of the platelet AlO(OH) nano colloids were investigated by XRD, TEM, TG/DTA, FT-IR and $N_2$ BET method in liquid nitrogen temperature.

Surfaces Properties of ${\alpha}-Sulfonated$ Fatty Acid Polyethylene Glycol Esters (알파술폰 고급지방산 폴리에틸렌글리콜 에스테르류의 계면물성)

  • Kim, J.H.;Yeon, Y.H.;Yun, Y.G.;Nam, K.D.
    • Journal of the Korean Applied Science and Technology
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    • v.15 no.2
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    • pp.11-24
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    • 1998
  • All the surface activities including surface tension, foaming power, foam stability, emulsifying power, dispersion effect, and detergency were measured and critical micelle concentration(cmc) was evaluated in dilute aqueous solution. The cmc evaluated by the Ring method was $10^{-3}{\sim}10^{-4}mol/L$ in case of monoesters, and $10^{-3}{\sim}5.0{\times}10^{-5}mol/L$ in case of diesters, respectively. Surface tension of the aqueous solution was decreased to $45{\sim}50dyne/cm$, showing the tendency that the ability of lowering the surface tension was dependent on increasing of carbon atom number in alkyl chain. Foaming power of all the monoesters was better than that of diesters. while foam stability of diesters was to the contrary. Emulsifying power of soybean oil or benzene was specially expected to be good for emulsifiers in industrial application fields. HLB values of monoesters and diesters evaluated by Griffin's method were in the range of 8 to 12. Dispersion property of ferric oxide was stable in the range of $4.5{\times}10^{-5}{\sim}5.0{\times}^{-4}mol/L$ in case of monoesters, and $10^{-5}{\sim}10^{-4}mol/L$ in case of diesters.

Hydration-Setting Property of β-Hemihydrate Gypsum by Adding of Accelerator and Ground Gypsum (경화촉진제 및 마쇄 이수석고 첨가에 의한 β-반수석고의 수화응결 특성)

  • Choi, Jeong-Bong;Kim, Jong-Pal
    • Applied Chemistry for Engineering
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    • v.8 no.5
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    • pp.822-829
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    • 1997
  • When $Al_2(SO_4)_3$ as an accelerator was added to $\beta$-hemihydrate gypsum, the setting time, mobility and compressive strength properties of $\beta$-hemihydrate gypsum were examined with the adding of two types grounded gypsum crushed by ball mill. By 15wt% adding of 7% $Al_2(SO_4)_3$ dilute solution, the setting time of $\beta$-hemihydrate gypsum was sharply accelerated than that of non-added $\beta$-hemihydrate gypsum. When ground phospho gypsum(PG) and chemical gypsum(CG) were added to $\beta$-hemihydrate gypsum, the initial and final setting time of $\beta$-hemihydrate gypsum were accelerated markedly with the increasing of grinding time and added amount of ground phospho gypsum. Especially, this trend largely presented when ground phospho gypsum was added to $\beta$-hemihydrate gypsum. The compressive strength of $\beta$-hemihydrate gypsum added by ground phospho and chemical gypsum was largely increased at initial curing time such as 1, 3 days. Particularly, the compressive strength of $\beta$-hemihydrate gypsum added by ground phospho gypsum was increased by 15~20% than that of ground chemical gypsum.

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