• Title/Summary/Keyword: swelling

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Kinetic Characterization of Swelling of Liquid Crystalline Phases of Glyceryl Monooleate

  • Lee, Jae-Hwi;Choi, Sung-Up;Yoon, Mi-Kyeong;Choi, Young-Wook
    • Archives of Pharmacal Research
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    • v.26 no.10
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    • pp.880-885
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    • 2003
  • Research in this paper focuses on the kinetic evaluation of swelling of the liquid crystalline phases of glyceryl monooleate (GMO). Swelling of the lamellar and cubic liquid crystalline phases of GMO was studied using two in vitro methods, a total immersion method and a Franz cell method. The swelling of the lamellar phase and GMO having 0 %w/w initial water content was temperature dependent. The swelling ratio was greater at $20^{\circ}^C than 37^{\circ}^C$ . The water uptake increased dramatically with decreasing initial water content of the liquid crystalline phases. The swelling rates obtained using the Franz cell method with a moist nylon membrane to mimic buccal drug delivery situation were slower than the total immersion method. The swelling was studied by employing first-order and second-order swelling kinetics. The swelling of the liquid crystalline phases of GMO could be described by second-order swelling kinetics. The initial stage of the swelling (t < 4 h) followed the square root of time relationship, indicating that this model is also suitable for describing the water uptake by the liquid crystalline matrices. These results obtained from the current study demonstrate that the swelling strongly depends on temperature, the initial water content of the liquid crystalline phases and the methodology employed for measuring the swelling of GMO.

Characteristics of expansive soils improved with cement and fly ash in Northern Thailand

  • Voottipruex, Panich;Jamsawang, Pitthaya
    • Geomechanics and Engineering
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    • v.6 no.5
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    • pp.437-453
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    • 2014
  • This paper studies the swelling and strength characteristics of unimproved and improved expansive soils in terms of the swell potential, swelling pressure, rate of secondary swelling, unconfined compressive strength and California bearing ratio (CBR). The admixtures used in this study are locally available cement and fly ash. The soils used in this study were taken from the Mae Moh power plant, Lampang Province, in northern Thailand. A conventional consolidation test apparatus was used to determine the swelling of the soil specimen. The optimum admixture contents are determined to efficiently reduce the swelling of unimproved soil. The rate of secondary swelling for unimproved soil is within the range of highly plastic montmorillonite clay, whereas the specimens improved with optimum admixture contents can be classified as non-swelling kaolinite. A soil type affects the swelling pressure. Expansive soil improvement with fly ash alone can reduce swelling percentage but cannot enhance the unconfined compressive strength and CBR. The strength and swelling characteristics can be predicted well by the swelling percentage in this study.

The Effect of Swelling on the Properties of Lyocell Fabric(I) -The Changes of Yarn and Fabric Structure- (팽윤도가 Lyocell 직물의 성질에 미치는 영향(I) -실과 직물의 구조를 중심으로-)

  • 정영진
    • Textile Science and Engineering
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    • v.38 no.5
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    • pp.244-249
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    • 2001
  • The effects of swelling of lyocell fiber and yarn on fabric structure have been studied. As the concentration of NaOH solution increases, the degree of swelling of lyocell fiber and yarn increases together up to the critical concentration, above the critical concentration, the degree of swelling starts to decrease. The swelling of lyocell yarn causes fabric thickness to increase and fabric length in warp and weft directions to decrease. This is due to the fact that yarn inflates in the direction perpendicular to the fabric surface when excessive swelling occurs. The amount of contraction in warp direction is greater than weft direction because of the differences in crimp and tension applied to the yarn during weaving. Also yarn length changes after swelling and drying because of structure change of yarn. Yarn length after drying is longer than after swelling. This is due to the relaxation of the induced stress by swelling and the reduction of restrictions between fibers. The structural change of swollen fabric by drying is not much, therefore, the status of swollen fabric is very important.

Swelling Pressures of a Potential Buffer Material for High-Level Waste Repository

  • Lee, Jae-Owan;Cho, Won-Jin;Chun, Kwan-Sik
    • Nuclear Engineering and Technology
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    • v.31 no.2
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    • pp.139-150
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    • 1999
  • The swelling pressure of a potential buffer material was measured and the effect of dry density, bentonite content and initial water content on the swelling pressure was investigated to provide the information for the selection of buffer material in a high-level waste repository. Swelling tests were carried out according to Box-Behnken's experimental design. Measured swelling pressures were in the wide range of 0.7 Kg/$\textrm{cm}^2$ to 190.2 Kg/$\textrm{cm}^2$ under given experimental conditions. Based upon the experimental data, a 3-factor polynomial swelling model was suggested to analyze the effect of dry density, bentonite content and initial water content on the swelling pressure The swelling pressure increased with an increase in the dry density and bentonite content, while it decreased with increasing the initial water content and, beyond about 12 wt.% of the initial water content, levelled off to nearly constant value.

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Synthesis and Swelling Kinetics of a Cross-Linked pH-Sensitive Ternary Copolymer Gel System (pH-민감성 삼성분계 공중합체 젤의 합성 및 팽윤 속도론)

  • Zafar, Zafar Iqbal;Malana, M.A.;Pervez, H.;Shad, M.A.;Momma, K.
    • Polymer(Korea)
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    • v.32 no.3
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    • pp.219-229
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    • 2008
  • A pH sensitive ternary copolymer gel was synthesized in the presence of ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent through radical polymerization of vinyl acetate (VA), acrylic acid (AA) and methyl acrylate(MA) with a weight ratio of 1 : 1.3 : 1. A number of experiments were carried out to determine the swelling behavior of the gel under a variety of pH conditions of the swelling medium. As the pH of the swelling medium was changed from 1.0 to 8.0 at $37^{\circ}C$, the gel showed a shift in the pH-dependent swelling behavior from Fickian (n=0.3447) to non-Fickian (n=0.9125). The resulting swelling parameters were analyzed using graphical and statistical methods. The results showed that the swelling of the gel was controlled by the pH of the medium, i.e. $n=n_o{\exp}(S_{C}pH)$, where n is the diffusion exponent, $n_o(=28.9645{\times}10^{-2})$ is the pre-exponential factor and $S_C$(=0.1417) is pH sensitivity coefficient. The swelling behavior of the gel was also examined in aliphatic alcohols. The results showed that the rate of swelling increased with increasing number of carbon atoms in the alcoholic molecular chain.

A new method to predict swelling pressure of compacted bentonites based on diffuse double layer theory

  • Sun, Haiquan
    • Geomechanics and Engineering
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    • v.16 no.1
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    • pp.71-83
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    • 2018
  • Compacted bentonites were chosen as the backfill material and buffer in high level nuclear waste disposal due to its high swelling pressure, high ion adsorption capacity and low permeability. It is essential to estimate the swelling pressure in design and considering the safety of the nuclear repositories. The swelling pressure model of expansive clay colloids was developed based on Gouy-Chapman diffuse double layer theory. However, the diffuse double layer model is effective in predicting low compaction dry density (low swelling pressure) for certain bentonites, and invalidation in simulating high compaction dry density (high swelling pressure). In this paper, the new relationship between nondimensional midplane potential function, u, and nondimensional distance function, Kd, were established based on the Gouy-Chapman theory by considering the variation of void ratio. The new developed model was constructed based on the published literature data of compacted Na-bentonite (MX80) and Ca-bentonite (FoCa) for sodium and calcium bentonite respectively. The proposed models were applied to re-compute swelling pressure of other compacted Na-bentonites (Kunigel-V1, Voclay, Neokunibond and GMZ) and Ca-bentonites (FEBEX, Bavaria bentonite, Bentonite S-2, Montigel bentonite) based on the reported experimental data. Results show that the predicted swelling pressure has a good agreement with the experimental swelling pressure in all cases.

Assessment of the swelling potential of Baghmisheh marls in Tabriz, Iran

  • Asghari-Kaljahi, Ebrahim;Barzegari, Ghodrat;Jalali-Milani, Shahrokh
    • Geomechanics and Engineering
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    • v.18 no.3
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    • pp.267-275
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    • 2019
  • Tabriz is a large Iranian city and the capital of the East Azerbaijan province. The bed rock of this city is mainly consisted of marl layers. Marl layers have some outcrops in the northern and eastern parts of city that mainly belong to the Baghmisheh formation. Based on their colors, these marls are classified into three types: yellow, green, and gray marls. The city is developing toward its eastern side wherein various civil projects are under construction including tunnels, underground excavation, and high-rise building. In this regard, the swelling behavior assessment of these marls is of critical importance. Also, in lightweight structures with foundation pressure less than swelling pressure, several problems such as walls cracking and jamming of door and windows may occur. In the present study, physical properties and swelling behavior of Baghmisheh marls are investigated. According to the X-ray diffractometer (XRD) results, the marls are mainly composed of Illite, Kaolinite, Montmorillonite, and Chloride minerals. Type and content of clay minerals and initial void ratio have a decisive role in swelling behavior of these marls. The swelling potential of these marls was investigated using one-dimensional odometer apparatus under stress level up to 10 kPa. The results showed that yellow marls have high swelling potential and expansibility compared to the other marls. In addition, green and gray marls showed intermediate and low swelling potential and swelling pressure, respectively.

Swelling Properties of Poly(ethylene terephthalate) Fiber in Mixed Solvent(I) -Rate of Swelling- (혼합용매중에서의 Poly(ethylene terephthalate) 섬유의 팽윤성(I) -팽윤속도-)

  • 이문철;박병기;조현혹
    • Textile Coloration and Finishing
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    • v.6 no.3
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    • pp.37-43
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    • 1994
  • Commercial Poly(ethylene terephthalate) (PET) filaments were treated in solvents mixtures such as benzyl alcohol/perchloroethylene(BA/PER), benzyl alcohol/trichloroethylene(BA/TRI), benzyl alcohol/ethylene chloride(BA/EC), metha nol/perchloroethylene(ME/PER), and methanol/trichloroethyle(ME/TRI). Swelling of PET in solvent mixtures showed rapidly in the middle range of mixture ratio. Contribution of swelling of each component to total swelling of binary mixtures with increasing treated time was generally showed in proportion to the mixture ratio of the each component in dependence of the extend of swelling.

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Alkali-Swollen Morphology of Native Cellulose Fibers

  • Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.2
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    • pp.16-22
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    • 2007
  • The behavior of ramie fibers and some wood elements in the early stage of alkali swelling was examined. When the fibers were treated with alkali solution, they significantly shrank in length and swelled in wall thickness. Ramie fibers showed a shrinkage averaging 23% in length and a swelling averaging 92% in width in 100 seconds treating time. Dimensional changes showed different fashion in each element of woods. The tracheids of latewood especially in Pinus densiflora and Larix kaempferi woods swelled intensively and showed balloon swelling, but in the case of Cryptomeria japonica, it was hardly observed. The swelling morphology of libriform fibers was similar to that of tracheids. The walls of vessel elements and parenchyma cells also swelled considerably in thickness but, no balloon swelling was found in both elements. The differences of swelling in different elements can be interpreted in terms of the differences of organization and/or chemical components of the cell walls.

Microscopic Interpretation on Thickness Swelling Mechanism of Nonwoven Web Composites from Wood Particles and Polypropylene Fibers

  • Chae, Shoo-Geun;Eom, Young-Geun
    • Journal of the Korea Furniture Society
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    • v.17 no.2
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    • pp.9-23
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    • 2006
  • Control particleboards were significantly higher in thickness swelling than wood particle-polypropylene fiber composites and their thickness swelling increased with the increase of target density. In the composites, thickness swelling did not vary significantly with the increase of target density but increased with the increase of wood particle content. And the composites with fine wood particles were significantly lower in thickness swelling than those with coarse wood particles irrespective of target density and formulation. In the scanning electron microscopy, significantly higher thickness swelling in the composites with coarse wood particles was thought to be the result of more interfacial separations by higher swelling stresses.

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