• Title/Summary/Keyword: Immobile zone

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First-Order Mass Transfer in a Diffusion-Dominated (Immobile) Zone of an Axisymmetric Pore: Semi-Analytic Solution and Its Limitations (대칭형 다공성 매질의 확산주도 영역에 관한 1차 물질이동 방정식)

  • Kim, Young-Woo;Kang, Ki-jun;Cho, Jung-ho;Kabala, Zbigniew
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.11
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    • pp.4664-4670
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    • 2010
  • Comparison of the classical mobile-immobile zone (MIM) model to the derived model led to several conclusions. If the MIM model is to be applied, the initial concentration in the immobile zone has to be down-scaled by a correction factor that is a function of pore geometry. The MIM model was valid only after sufficiently long time has passed, i.e., only after the diffusion front reaches the deepest pore wall in the immobile zone. The MIM mass-transfer coefficient $\alpha$, was inversely proportional to the square of the pore depth. Also it did not depend on the mobile-zone flow velocity, contrary to the number of laboratory and field observations. The classical MIM model displayed a rapid exponential decay of immobile-zone concentration. Meanwhile at large times, the newly derived model displayed similar exponential decay. This was contrary to the mounting evidence of power-law BTC tails observed in laboratory and field settings.

Derivation of the First-Order Mass-Transfer Equation for a Diffusion-Dominated Zone of a 2-D Pore (2차원으로 구현한 다공성 매질의 확산주도영역에 관한 1차 물질이동 방정식의 유도)

  • Kim, Young-Woo;Seo, Byong-Min;Hwang, Seung-Min;Park, Cha-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.2
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    • pp.99-103
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    • 2010
  • A new analytic solution was derived for the diffusion into or from an immobile zone of a rectangular 2-D pore. For a long time, the new solution converges to a traditional mobile-immobile zone (MIM) model, but only if the latter is used with an apparent initial concentration that is smaller by almost 20% than the true one. This is the tradeoff for using a simple MIM model instead of an exact model based on the diffusion equation. The mass-transfer coefficient was found to be constant for a sufficiently long time; it was proportional to the molecular diffusion and inversely proportional to the square of the pore depth. The mass-transfer coefficient was time-dependent for a sufficiently short time and may be significantly larger than its asymptotic value.

First-Order Mass Transfer in a Vortex-Dispersion Zone of an Axisymmetric Groove: Laboratory and Numerical Experiments

  • Kim, Young-Woo;Kang, Ki-Jun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.6
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    • pp.651-657
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    • 2010
  • Solute transport through a groove is affected by its vortices. Our laboratory and numerical experiments of dye transport through a single axisymmetric groove reveal evidence of enhanced spreading and mixing by the vortex, i.e., a new kind of dispersion called here the vortex dispersion. The uptake and release of contaminants by vortices in porous media is affected by the flow Reynolds number. The larger the flow Reynolds number, the larger is the vortex dispersion, and the larger is the mass-transfer rate between the mobile zone and the vortex. The long known dependence of the mass-transfer rate between the mobile and "immobile" zones in porous media on flow velocity can be explained by the presence of vortices in the "immobile" zone and their uptake and release of contaminants.

Perturbation Analysis of Stokes Flow in Porous Medium (다공성 매질의 내부유동에 관한 섭동해석)

  • Seong, Kwanjae
    • Journal of Korean Society on Water Environment
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    • v.21 no.4
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    • pp.393-397
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    • 2005
  • In this study, flow in a porous medium is analyzed using a computer-extended perturbation series solution. The flow is modelled as a creeping flow in a periodically constricted channel. The channel walls have a sinusoidally varying width and the flow is analyzed in terms of its vorticity and stream functions in the Stokes flow regime. The perturbation series in terms of a small parameter, average width to length ratio, is extended with a computer resulting in purely asymptotic series and Pade summation is used to obtain final results. Resulting flow shows flow separations in the widening section and immobile zones in the widest section of the flow regime with reattachment in the narrowing section. Analysis of the flow separation phenomena resulted in a correlation between the two geometric parameters of the channel walls to predict the onset of flow separation in the Stokes flow regime.

Bioremediation by Denitrification in the Saturated Zone : Mathematical Model and Experiment

  • Lee Eun-Jung;Lee Kang-Kun;Kim Young;Ha Cheol-Yun
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2005.04a
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    • pp.393-396
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    • 2005
  • The reactive transport model on the biologically mediated sequential nitrate transformation and its subsequent transport was developed and tested. This model was coded as a reaction module within the RT3D framework (Clement, 1997). Transports of the reasonable six mobile solutes (dissolved organic carbon, $O_2,\;{NO_3}^-,\;{NO_2}^-,\;N_2O,\;N_2$) and two immobile microbes were simulated. The simulation results gave a reasonable match with supposed transport pattern. For the next step, the developed model will be validated against experimental data.

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Magamtism and Metamorphism of the Proterozoic in the Northeastern Part of Korea: Tectonomagmatic Characteristics of the Imgye Hornblendites (한국(韓國) 북동부지역(北東部地域) 원생대(原生代)의 화성활동(火成活動)과 변성작용(變成作用) : 임계(臨溪) 각섬암(角閃岩)의 암석성인(岩石成因)과 조구조적(造構造的) 특징(特徵))

  • Chang, Ho-Wan;Lee, Dong-Hwa
    • Economic and Environmental Geology
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    • v.26 no.4
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    • pp.499-505
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    • 1993
  • The Imgye hornblendites occur as intrusive sills or dykes within the mylonite zone developed along the contact boundary between Precambrian Jungbongsan granite and Cambrian Jangsan quartzite or Myobong slate formations. The hornlendites belong to the subalkaline and tholeiitic series. In tectonomagmatic discrimination diagrams such as $TiO_2-K_2O-P_2O_5$, 2Nb-Zr/4-Y and $TiO_2-10MnO-10P_2O_5$, the hornblendites are classified into continental- and island-arc tholeiites. The hornblendites show fractionated REE patterns with $(La/Yb)_{CN}$ ranging from 3.73-4.56. In incompatible element abundance variations, the hornblendites show distinctive positive and negative anomalies for Rb and Nb, respectively, and unfractionated patterns of immobile incompatible elements such as Y and Yb. The REE patterns of the hornblendites are also similar to those of typical continental back-arc tholeiites and those of the Precambrian Okbang amphibolites in the Socheon-meon, Bonghwa-gun. Accoiding to geochemical characteristics above-mentioned, the hornblendites seem to have been formed from tholeiitic magmas of depleted upper mantle source, contaminated by crustal material en route to continental back-arc basin.

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Clinical Experience of Finger Tip Amputation of Small Finger in 12-Months-Old: Use of the Technique of Artery-Only Anastomosis (단일동맥연결을 통한 유아 새끼 손가락끝 재접합 경험)

  • Kim, Sun-Joo;Choi, Hwan-Jun;Lee, Young-Man;Kim, Yong-Bae
    • Archives of Reconstructive Microsurgery
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    • v.18 no.1
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    • pp.27-30
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    • 2009
  • Purpose: Recently, replantation of fingertip amputation, Zone I by Yamano classification, is still difficult because digital arteries branch into small arteries and also digital veins are hard to separate from the immobile soft tissue. However the replantation of fingertip in adults is a well-established procedure, but the replantation in infant or child is still uncommon. Therefore we present one case of replantation of the fingertip of the small finger in 12-months-old patient. Methods: We experienced a 12-months-old male amputation of small finger. It had been amputated completely at the level of Zone I by Yamano classification. Replantation was performed using the arteryonly technique with neither vein nor nerve repair. Because the artery has been damaged, it is still possible to make a direct suture by transposing the arterial arch in an inverted Y to I arterial configuration. Venous drainage was provided by an external bleeding method with partial nail excision and repaired margin for approximately 7 days. Results: We were performed replantation in infant with only-arterial anastomosis successfully, result in good recovery of aesthetic and functional outcome. Conclusion: In conclusion, although fingertip injury was difficult to replantation in infant and child, we must try it. Because of its functional and cosmetic advantage.

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Effects of the Acute Exposure Oxytetracycline on the Behavior and Endocrine Response in Adult Zebrafish (Oxytetracycline의 단기 노출이 제브라피쉬의 행동 및 내분비 반응에 미치는 영향)

  • Ko, Eun Seong;Lee, Seungheon
    • Journal of Life Science
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    • v.25 no.2
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    • pp.151-157
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    • 2015
  • Zebrafish (Danio rerio) has been more widely used to study pharmacology. Oxytectracycline (OTC) is a broad-spectrum antibiotic and works by interfering with the ability to produce essential proteins of bacteria. The aim of this study was to identify the effects of exposure to OTC on behavioral changes or endocrine response in zebrafish. The behavioral effects of exposure to OTC (50, 100 or 200 mg/l) were characterized in several novelty-based paradigms such as the novel tank or open field test in zebrafish. Moreover, to investigate effects of exposure to OTC on endocrine response, we measured whole-body cortisol level using cortisol ELISA kit. As results of novel tank test, duration in top and immobile duration were significantly increased by the exposure to OTC in a concentration-dependent manner (p<0.05). In addition, moving distance, highly mobile, velocity and zone transition were significantly decreased by the exposure to OTC in a concentration-dependent manner (p<0.05). As results of open field test, the exposure to OTC increased immobile duration significantly (p<0.05). However, moving distance, mobile duration and velocity were significantly decreased by the exposure to OTC in a concentration-dependent manner (p<0.05). Besides, the exposure to OTC elevated whole-body cortisol levels in zebrafish. These results suggest that the exposure to OTC may induce chemical stress in zebrafish.

Microsurgical Replantation of Very Distally Amputated Finger (수지 첨부 절단의 재접합술)

  • Kang, Hong-Dae;Kim, Johng-Jin;Lee, Nae-Ho;Yang, Kyung-Moo;Moon, Ji-Hyun
    • Archives of Reconstructive Microsurgery
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    • v.16 no.2
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    • pp.75-81
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    • 2007
  • Introduction: Microsurgical replantation of amputated digit have become common procedure in recent years. However replantation of fingertip amputation, Zone I by Yamano classification, is still difficult because digital arteries branch into small arteries and also digital veins are hard to separate from the immobile soft tissue. So, fingertip amputation was covered by volar V-Y flap, composite graft, cross finger flap and groin flap. But patients who have been treated by these methods experience shortening of digit, nail deformity, excessive tenderness and persistent pain. Replantation could solve most of these problems. Material & Methods: In our department, from March 2004 to August 2007, 36 digits in 32 patients with complete amputation at distal to nail base were replanted using a microsurgical technique. Results: The overall survival rate of the replanted finger was 75%. Venous anastomosis was possible in 8 cases and impossible in 28 cases. In latter cases external bleeding technique was applied with medical leech. Conclusion: After replantation, a few patient complained decreased sensibility, nail deformity and cold intolerance. But most of patients were satisfied with the functional and cosmetic appearance of the viable replanted digits. We believe the replantation should be the first choice in fingertip amputation.

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Mineralogy and Genesis of Hydrothermal Deposits in the Southeastern Part of Korean Peninsula : (5) Deogbong Napseok Deposit (우리나라 동남부 지역의 열수광상에 대한 광물학적 및 광상학적 연구:(5) 덕봉납석광상)

  • Kim, Soo-Jin;Choo, Chang-Oh;Kim, Won-Sa
    • Journal of the Mineralogical Society of Korea
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    • v.7 no.1
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    • pp.25-39
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    • 1994
  • The Deogbong napseok clay deposit which is composed mainly of dickite and pyrophyllite has been formed by hydrothermal alteration of the Late Cretaceous volcanic rocks consisting of andesitic tuff and andesite. The mineralogy of the napseok ores and the hydrothermal alteration processes have been studied in order to know the nature of the interaction between minerals and fluids for the formation of the deposit. Chemical distribution shows that alkali elements and silica were mobile but alumina was relatively immobile during the hydrothermal processes. It is evident that enrichment of alumina and leaching of silica from the host rock led to the formation of the napseok ore, whereas the enrichment of silica in the outer zone of the deposit gave rise to the silica zone. A large amount of microcrystalline quartz closely associated with dickite and pyrophyllite suggests the increasing activity of silica. Thus Si which was released away from the argillic zone by the increasing activity of silica. Thus Si which was released away from the argillic zone by the increasing activity of silica solubility moved out precipitating in the margin of the deposit to form the silica zone. Variation in dickite crystallinity implies the local change in the stability of the system. Thermodynamic calculation shows that the invariant point of pyrophyllite-dickite (kaolinite)-diaspore-quartz assemblages at 500 bars in the system $Al_{2}O_{3}-SiO_{2}-H_{2}O$ is about 300 $^{\circ}C$. Based on the mineral assemblages and the experimental data reported, it is estimated that the main episode of hydrothermal alteration occurred at least above 270 to 300 $^{\circ}C$ and $X_{CO_2}$ <0.025. Mineral occurrence and chemical variation indicate that the activity of Al is high in the upper part of the deposit, whereas the activity of Si is high in the lower part and the margin of the deposit. The nonequilibrium phase relations observed in the Deogbong deposit might be due to local change in intensive thermodynamic variables and fluid transport properties that resulted in the formation of nonequilibrium phases b of several stages.

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