• Title/Summary/Keyword: permeability model

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Soil-Water Characteristic Curve of Sandy Soils Containing Biopolymer Solution (바이오폴리머를 포함한 모래지반의 흙-습윤 특성곡선 연구)

  • Jung, Jongwon
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.10
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    • pp.21-26
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    • 2018
  • Soil-water characteristic curve, which is called soil retention curve, is required to explore water flows in unsaturated soils, relative permeability of water in multi-phase fluids flow, and change to stiffness and volume of soils. Thus, the understanding of soil-water characteristic curves of soils help us explore the behavior of soils inclduing fluids. Biopolymers are environmental-friendly materials, which can be completely degraded by microbes and have been believed not to affect the nature. Thus, various biopolymers such as deacetylated power, polyethylene oxide, xanthan gum, alginic acid sodium salt, and polyacrylic acid have been studies for the application to soil remediation, soil improvement, and enhanced oil recovery. PAA (polyacrylic acid) is one of biopolymers, which have shown a great effect in enhanced oil recovery as well as soil remediation because of the improvement of water-flood performance by mobility control. The study on soil-water characteristic curves of sandy soils containing PAA (polyacrylic acid) has been conducted through experimentations and theoretical models. The results show that both capillary entry pressure and residual water saturation dramatically increase according to the increased concentration of PAA (polyacrylic acid). Also, soil-water characteristic curves by theoretical models are quite well consistent with the results by experimental studies. Thus, soil-water characteristic curves of sandy soils containing biopolymers such as PAA (polyacrylic acid) can be estimated using fitting parameters for the theoretical model.

Skin Barrier Recovery by Protease-Activated Receptor-2 Antagonist Lobaric Acid

  • Joo, Yeon Ah;Chung, Hyunjin;Yoon, Sohyun;Park, Jong Il;Lee, Ji Eun;Myung, Cheol Hwan;Hwang, Jae Sung
    • Biomolecules & Therapeutics
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    • v.24 no.5
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    • pp.529-535
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    • 2016
  • Atopic dermatitis (AD) results from gene and environment interactions that lead to a range of immunological abnormalities and breakdown of the skin barrier. Protease-activated receptor 2 (PAR2) belongs to a family of G-protein coupled receptors and is expressed in suprabasal layers of the epidermis. PAR2 is activated by both trypsin and a specific agonist peptide, SLIGKV-$NH_2$ and is involved in both epidermal permeability barrier homeostasis and epithelial inflammation. In this study, we investigated the effect of lobaric acid on inflammation, keratinocyte differentiation, and recovery of the skin barrier in hairless mice. Lobaric acid blocked trypsin-induced and SLIGKV-$NH_2$-induced PAR2 activation resulting in decreased mobilization of intracellular $Ca^{2+}$ in HaCaT keratinocytes. Lobaric acid reduced expression of interleukin-8 induced by SLIGKV-$NH_2$ and thymus and activation regulated chemokine (TARC) induced by tumor necrosis factor-a (TNF-${\alpha}$) and IFN-${\gamma}$ in HaCaT keratinocytes. Lobaric acid also blocked SLIGKV-$NH_2$-induced activation of ERK, which is a downstream signal of PAR2 in normal human keratinocytes (NHEKs). Treatment with SLIGKV-$NH_2$ downregulated expression of involucrin, a differentiation marker protein in HaCaT keratinocytes, and upregulated expression of involucrin, transglutamase1 and filaggrin in NHEKs. However, lobaric acid antagonized the effect of SLIGKV-$NH_2$ in HaCaT keratinocytes and NHEKs. Topical application of lobaric acid accelerated barrier recovery kinetics in a SKH-1 hairless mouse model. These results suggested that lobaric acid is a PAR2 antagonist and could be a possible therapeutic agent for atopic dermatitis.

Study on the Characteristics of Shear Strength on the Weathered Granite Soil Slope in Accordance with the Rainfall (강우에 따른 화강암질 풍화토 사면의 전단강도 특성에 관한 연구)

  • Shim Tae-Sup;Kim Sun-Hak;Ki Wan-Seo;Joo Seung-Wan
    • The Journal of Engineering Geology
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    • v.14 no.4 s.41
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    • pp.349-360
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    • 2004
  • This study calculated the pore water pressure, the depth of seepage, the constant of the strength in accordance with the slope inclination and the rainfall intensity over the slope built by the weathered granite soil (SP, SM). And, the change of the shear strength in accordance with the rainfall has been compared and analyzed by applying the shear strength formula of the unsaturated soil. As a result, the rainfall intensity is stronger and the slope inclination is gentler the seepage speed in accordance with the rainfall became faster proportionally. As a result of comparing and analyzing both the theoretical value of Lumb and the actual value of the model, it can be said that the actual value is faster. Since SM shows the bigger shear strength than SP, it can also be said that as the granules increase, the coefficient of permeability becomes smaller; and as the seepage rate became smaller, it affects the seepage speed. Likewise, the shear strength within the slope displays the smallest shear strength at the inclination of 1:1.5 the reason of its decrease turned out that it was due to the increase of the pore water pressure.

Long-Term Performance Evaluation of Concrete Utilizing Oyster Shell in Lieu of Fine Aggregate (굴패각을 잔골재로 대체 사용한 콘크리트의 장기성능 평가)

  • Yang, Eun-Ik;Yi, Seong-Tae;Kim, Hak-Mo;Shim, Jae-Seol
    • Journal of the Korea Concrete Institute
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    • v.15 no.2
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    • pp.280-287
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    • 2003
  • To evaluate the practical application of oyster shells(OS) as construction materials, an experimental study was performed. More specifically, the long-term mechanical properties and durability of concrete blended with oyster shells were investigated. Test results indicate that long-term strength of concrete blended with 10% oyster shells is almost identical to that of normal concrete. However, the long-term strength of concrete blended with 20% oyster shells is appreciably lower than that of normal concrete. Thereby, concrete with higher oyster shell blend has the possibility of negatively influencing the concrete long-term strength. Elastic modulus of concrete blended with crushed oyster shells decreases as the blending mixture rate increases. Namely, the modulus is reduced to approximately 10∼15% when oyster shells are blended up to 20% as the fine aggregate. The drying shrinkage strain increases with an increasing crushed oyster shells substitution rate. In addition, the existing model code of drying shrinkage and creep do not coincide with the test results of this study. An adequate prediction equation needs to be developed. The utilization of oyster shells as the fine aggregate in concrete has an insignificant effect on fleering and thawing resistance, carbonation and chemical attack of concrete. However, water permeability is considerably improved.

New Flood Hazard Mapping using Runoff Mechanism on Gamcheon Watershed (유출메커니즘을 활용한 감천유역에서의 새로운 홍수위험지도 작성)

  • Kim, Tae Hyung;Han, Kun Yeun;Park, Jun Hyung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.6
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    • pp.1011-1021
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    • 2016
  • This study performs the potential flood hazard analysis by applying elevation data, soil data and land use data. The susceptibility maps linked to elevation, soil and land use are combined to develop the new types of flood hazard map such as runoff production map and runoff accumulation map. For the development of the runoff production map, land use, soil thickness, permeability, soil erosion and slope data are used as runoff indices. For the runoff accumulation map, elevation, knick point and lowland analysis data are used. To derive an integrated type of flood potential hazard, a TOPSIS (The Technique for Order of Preference by Similarity to Ideal Solution) technique, which is widely applied in MCDM (Multi-Criteria Decision Making) process, is adopted. The indices applied to the runoff production and accumulation maps are considered as criteria, and the cells of analysis area are considered as alternatives for TOPSIS technique. The model is applied to Gamcheon watershed to evaluate the flood potential hazards. Validation with large scale data shows the good agreements between historical data and runoff accumulation data. The analysis procedure presented in this study will contribute to make preliminary flood hazard map for the public information and for finding flood mitigation measures in the watershed.

Modeling Study on a Circulatory Hollow-Fiber Membrane Absorber for $CO_{2}$ Separation (이산화탄소 분리를 위한 순환식 중공사 막흡수기에 관한 모델링 연구)

  • Chun, Myung-Suk;Lee, Kew-Ho
    • Membrane Journal
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    • v.5 no.1
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    • pp.35-43
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    • 1995
  • For several years lots of attempts have been made to establish the liquid membrane-based techniques for separations of gas mixtures especially containing carbon dioxide. A more effective system to separate $CO_{2}$ from flue gases, a circulatory hollow-fiber membrane absorber(HFMA) consisting of absorption and desorption modules with vacuum mode, has been considered in this study. Gas-liquid mass transfer has been modeled on a membrane module with non-wetted hollow-fibers in the laminar flow regime. The influence of an absorbent flow rate on the separation performance of the circulatory HFMA can be predicted quantitatively by obtaining the $CO_{2}$ concentration profile in a tube side. The system of $CO_{2}/N_{2}$ binary gas mixture has been studied using pure water as an(inert) absorbent. As the absorbent flow rate is increased, the permeation flux(i.e., defined as permeation rate/membrane contact area) also increases. The enhanced selectivity compared to the previous results, on the other hand, shows the decreasing behavior. It has been found obviously that the permeation flux depends on the variations of pressure in gas phase of desorption module. From an accurate comparison with the results of conventional flat sheet membrane module, the advantageous permeability of this circulatory HFMA can be clearly ascertained as expected. Our efforts to the theoretical model will provide the basic analysis on the circulatory HFMA technique for a better design and process.

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A Coupled Hydro-Mechanical Analysis of a Deep Geological Repository to Assess Importance of Mechanical Factors of Bentonite Buffer (심층 처분 시설의 수리 역학적 해석을 통한 벤토나이트 버퍼의 역학적 영향 인자 중요도 평가)

  • Jeon, Yoon-Soo;Lee, Seung-Rae;Kim, Min-Seop;Jeon, Jun-Seo;Kim, Min-Jun
    • Tunnel and Underground Space
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    • v.29 no.6
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    • pp.439-455
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    • 2019
  • A buffer is the major component of a high level radioactive waste repository. Due to their thermal conductivity and low permeability, bentonites have been considered as a key component of a buffer system in most countries. The deep geological condition generates ground water inflow and results in swelling pressure in the buffer and backfill. Investigation of swelling pressure of bentonite buffer is an important task for the safe disposal system. The swelling pressure that can be critical is affected by mechanical and hydro properties of the system. Therefore, in this study, a sensitivity analysis was conducted to examine the effect of hydro-mechanical (HM) behaviors in the MX-80 bentonite. Based on the results of the swelling pressure generation with HM model parameters, a coupled HM analysis of an unsaturated buffer and backfill in a deep geological repository was also carried out to investigate the major factor of the swelling pressure generation.

In vivo Antinociceptive Antiinflamatory and Antioxidative Effects of the Leaf and Stem Bark of Kalopanax pictus in Rats (음나무 잎 및 수피의 진통소염효과 및 아주반트로 유발된 산화적 스트레스에 대한 효과)

  • Park, Hee-Juhn;Nam, Jung-Hwan;Jung, Hyun-Ju;Kim, Won-Bae;Park, Kwang-Kyun;Chung, Won-Yoon;Choi, Jong-Won
    • Korean Journal of Pharmacognosy
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    • v.36 no.4 s.143
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    • pp.318-323
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    • 2005
  • The leaves (KPL) of Kalopanax pictus (KP) are used as a vegetable or a functional food in Korean society. The stem bark (Kalopanacis Cortex, KPS) has been traditionally used to treat neurotic pain, rheumatoid arthritis and diabetic disease. This research was undertaken to demonstrate that the leaf extract of KP (KPL) has also the antinociceptive and antiinflammatory effects like the extract (KPS) of Kalopanacis Cortex and to compare the activity levels of several extracts obtained from KP. Antinociceptive and antiinflammatory effects were measured against the extracts described as followings; KPL-1 (the MeOH extract obtained from the leaf shoot of KP collected on May), KPL-2 (the MeOH extract from KP collected on June), KPL-3 (the MeOH ectract from KP with no thorns), KPS-1 (MeOH extract from KPS of a Korean habitat), KPS-2 (MeOH extract from KPS of a Chinese habitat). The antimociceptive test undertaken by acetic acid-induced writhing, hot plate-, and tail-flick methods using mice. The anti-inflammatory test was also undertaken by measuring the edema in the carrageenan-induced test. The order of activity potency in the antinociceptive and antiinflammatory assays was commonly shown as followings: KPL-3>KPS>1>KPS-2>KPL-1>KPL-2. This order was also observed in acetic acid-induced vascular permeability test. The antiinflammatory activity in carrageenan-induced assay was also observed as the following order: KPL-3>KPS- 1>PS-2>KPL-1>KPL-2. In addition, adjuvant-induced rats were used for a model to assess the oxidative stress. Treatment of the rat with the extracts reduced serum thiobarbituric acid-reactive substances (TBARS), hydroxy radical(OH) and superoxide dismutase(SOD) activity caused by FCA together together with the inhibition of hepatic TBARS level and lipofuscin content. The above finding suggests that the leaf extract has the antinociceptive and antinflammatory activity. It is also suggested that KPL-3 with more potent activity than other tested extracts could be developed for a new available biomaterial.

Demonstration of Developed Numerical Procedure to Describe 3-dimensional Long-term Behavior of the Pleistocene Marine Foundations (Pleistocene 해저지반의 3차원 장기거동 해석을 위해 개발한 수치해석 기법의 입증)

  • Yun, Seong-Kyu
    • Journal of the Korean Geotechnical Society
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    • v.36 no.7
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    • pp.5-14
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    • 2020
  • Kansai International Airport (KIX) was opened in September 1994. Although 26 years have passed since the completion of the first island, long-term settlement is still in progress. This settlement occurs in the Pleistocene layer. For it is not easy to determine the permeability of the Pleistocene sand layer because the thickness and the degree of fine content in the horizontal direction are constantly changing. In addition, it is also a difficult to predict the interactive behavior of the ground due to the construction of the second phase island adjacent to it. In order to solve this problem, a two-dimensional finite element analysis considering elasto-viscoplastic was performed to evaluate the long-term deformation, including the interactive behavior of the alternating Pleistocene foundation due to the construction of two adjacent reclaimed islands. In general, two-dimensional analysis can be used when a section can represent the entire sections. However, Kansai Airport is an artificial reclaimed island so two-dimensional analysis cannot solve the problem such as the stress deformation in the corners of the island. Additionally, the structure of the actual sub-ground through physical exploration is non-homogeneity and its thickness is also not constant. Therefore, there are limitations for the two-dimensional analysis to explain the phenomena. That is, three-dimensional analysis is strongly required. Due to these demands, the author extended the existing two-dimensional program capable of elasto-viscoplastic analysis to three-dimensional and completed the verification of the three-dimensional program developed through one-dimensional consolidation analysis. In order to demonstrate the validity of the developed 3D program that has been verified, an analysis is performed under the same analysis conditions as the existing research using a two-dimensional program. The effectiveness of the developed 3D numerical analysis program was demonstrated by comparing the analysis results with the 2D results and actual measurement data.

Drug Delivery into the Blood-Brain Barrier by Endogenous Substances-A Role of Amine and Monocarboxylic Acid Carrier Systems for the Drug Transport- (내인성물질의 수송계를 이용한 혈액-뇌관문에의 약물송달V-약물의 혈액-뇌관문 투과성에 대한 염기성 아민 및 모노카르본산 수송계의 역할-)

  • Kang, Young-Sook
    • Journal of Pharmaceutical Investigation
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    • v.20 no.4
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    • pp.223-228
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    • 1990
  • The contribution of endogenous transport systems to the blood-brain barrier (BBB) transport of basic and acidic drugs was studied by using a carotid injection technique in rats and an isolated bovine cerebrovascular disease state were compared between the normotensive rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP) which have been well established as an animal model with pathogenic similarities to humans. Basic drugs such as eperisone, thiamine and scopolamine inhibited, in a concentration dependent manner the in vivo uptake of $[{^3}H]choline$ through BBB, whereas amino acids and acidic drugs such as salicylic acid and valproic acid did not inhibit the uptake. The uptake of $[^3H]choline$ by B-CAP increased with time and showed a remarkable temperature dependency. The uptake of $[^3H]choline$ by B-CAP showed the very similar inhibitory effects as observed in the in vivo brain uptake, and was competitively inhibited by a basic drug, eperisone. The in vivo BBB uptakes of $[^3H]acetic$ acid and $[^{14}C]salicylic$ acid were dependent on pH of the injectate and the concentration of drugs. Several acidic drugs such such as salicylic acid, benzoic acid and valproic acid inhibited the in vivo uptake of $[^3H]acetic$ acid, whereas amino acid, choline and a basic drug such as eperisone did not inhibit the uptake. The uptake of acetic acid by B-CAP was competitively inhibited by salicylic acid. The permeability surface area product (PS) through BBB for $[^3H]choline$ in SHRSP was significantly lower than that in WKY. The concentration of choline in the brain dialysate in SHRSP was about half of that in WKY, while no significant difference was observed in the plasma concentration of choline between SHRSP and WKY. No significant difference was observed in the transport of monocarboxylic acids, glucose and neutral amino acid through BBB between SHRSP and WKY. From these results, it was concluded that BBB transport system of choline contributes to the transport of basic drugs through BBB, that acidic drugs can be transported via a moncarboxylic acid BBB transport system and that the specific dysfuntion of the BBB choline transport in SHRSP was ascribed to the reduction of the maximum velocity of choline concentration in the brain interstitial fluids.

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