• Title/Summary/Keyword: f-w curve

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Shaft Group Efficiency of Friction Pile Groups in Deep Soft Clay (대심도 마찰무리말뚝의 주면 무리효율 분석)

  • Paek, Jin-Yeol;Cho, Jae-Yeon;Jeong, Sang-Seom;Hwang, Taik-Jean
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.2C
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    • pp.49-60
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    • 2012
  • In this study, the behaviors of friction pile groups are investigated using 3D finite element (FE) analysis. The emphasis was quantifying on the shear load transfer (f-w) characteristics of pile groups and the shaft group effects. A framework for determining the f-w curve is proposed based on both theoretical analysis and field load test database. Through comparisons with case histories and FE results, it is shown that the proposed f-w curve is capable of predicting the behavior of a friction pile in deep soft clay. Additionally, a numerical analysis that takes into account the group efficiency factors were performed for major parameter on group pile-soil interaction, such as the pile spacing, pile arrangement, soil condition, and location of pile cap. Based on these results, the shaft group efficiency factors were also proposed.

Shear Load Transfer Characteristics of Friction Piles in Deep Soft Clay (대심도 연약지반상 마찰말뚝의 주면하중전이 거동 분석)

  • Moon, Joon-Shik;Paek, Jin-Yeol;Jeong, Sang-Seom;Ko, Jun-Young
    • Journal of the Korean Geotechnical Society
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    • v.27 no.10
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    • pp.55-67
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    • 2011
  • The shear load distribution and deformation of offshore friction piles are investigated using experimental tests and a numerical analysis. Special attention is given to the soil-pile interaction of axially loaded pile. A framework for determining the f-w curve is proposed based on both theoretical analysis and experimental load test data base. A numerical analysis that takes into account the proposed f-w curves was performed for major parameters on pile-soil interaction such as the pile diameter, the pile length, and the soil condition. Based on the analysis, it is shown that the proposed f-w method is capable of predicting the behavior of a friction pile in deep soft clay. Through comparisons with case histories and finite element results, it is found that the proposed f-w curves are more appropriate and realistic m representing the pile-soil interaction of axially loaded piles in deep soft clay than that of existing f-w method.

Load Transfer Mechanism of Drilled Shafts in Weathered Rock (풍화된 암반에 근입된 현장타설말뚝의 하중전이기구)

  • ;Cho Sung-Min;Jung Sung-Jun;Kim Myoung-Mo
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.187-196
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    • 2005
  • Since the allowable bearing capacities of piles in weathered/fractured rock are mainly governed by settlement, the load-displacement behavior of pile should be known accurately. To predict pile head settlement at the design stage, the exact understanding of the load-transfer mechanisms is essential. Therefore, in this research, the load-transfer mechanism of drilled shaft socketed into weathered rock was investigated. For the investigation, five cast-in-place concrete piles with diameters of 1,000 mm were socketed into weathered gneiss. The static axial load tests and the load-transfer measurements were performed to examine the axial resistant behavior of the piles. A comprehensive field/laboratory testing program on weathered rock at the Held test sites was also performed to describe the in situ rock mass conditions quantitatively. And then, the effect of rock mass condition on the load transfer mechanism was investigated. The f-w (side shear resistance-displacement) curve of the pile in moderately weathered rock reached to yielding point at a for millimeter displacements, and after yielding point, the rate of resistance increment dramatically decreased. However, the f-w curve in the highly/completely weathered rock did not show the obvious yielding point, and the resistance gradually increased showing the hyperbolic pattern until relatively high displacement (>15 mm). The q-w (end bearing resistance-displacement) curves showed linear response at least until the base displacement of approximately 10 mm, regardless of rock mass conditions.

SOME ANALYTIC IRREDUCIBLE PLANE CURVE SINGULARITIES

  • Kang, Chung-Hyuk
    • Journal of the Korean Mathematical Society
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    • v.33 no.2
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    • pp.367-379
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    • 1996
  • Let $V = {(z, y) : f(z, y) = z^n + Ay^\alpha z^p + y^\beta z^q + y^k = 0}$ and $W = {(z, y) : g(z, y) = z^n + By^\gamma z^s + y^\delta z^t + y^k = 0}$ be germs of analytic irreducible subvarieties of a polydisc near the origin in $C^2$ with n < k and (n, k) = 1 where A and B are complex numbers. Assume that V and W are topologically equivalent near the origin.

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Effect of Surfactants on Dissolution Rate of Mefenamic Acid Capsules (메페남산 캅셀의 용출에 미치는 계면활성제의 영향)

  • Jun, Young-Bin;Kim, Seung-In;Kim, Young-Il
    • Journal of Pharmaceutical Investigation
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    • v.20 no.3
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    • pp.121-127
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    • 1990
  • Mefenamic acid has been widely used clinically as an anti-inflammatory analgesic. It has poor solubility in water $(41\;{\mu}g/ml)$ and there is the difficulty of dissolution in the mefenamic acid capsules. A study was made to investigate the effect of various surfactants on the dissolution of mefenamic acid capsules. The surfactants used were sodium lauryl sulfate (SLS), Pluronic F-68, F-77, and F-127. Mefenamic acid capsule containing surfactant showed significantly improved dissolution characteristics. The dissolution rate was fast in the order of SLS > F-77 > F-68 > F-127 in mefenamic acid capsules containing 0.2 w/w % surfactant. SLS was selected for further study on the bioavailability in rabbits. The area under the plasma concentration-time curve $(AUC_{0-24})$ of mefenamic acid capsule containing SLS was higher than one of mefenamic acid capsule not containing surfactant.

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ON PARTIAL SOLUTIONS TO CONJECTURES FOR RADIUS PROBLEMS INVOLVING LEMNISCATE OF BERNOULLI

  • Gurpreet Kaur
    • Korean Journal of Mathematics
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    • v.31 no.4
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    • pp.433-444
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    • 2023
  • Given a function f analytic in open disk centred at origin of radius unity and satisfying the condition |f(z)/g(z) - 1| < 1 for a analytic function g with certain prescribed conditions in the unit disk, radii constants R are determined for the values of Rzf'(Rz)/f(Rz) to lie inside the domain enclosed by the curve |w2 - 1| = 1 (lemniscate of Bernoulli). This, in turn, provides a partial solution to the conjectures and problems for determination of sharp bounds R for such functions f.

The Fatigue Strength and the Fatigue Life Prediction in Plain Woven Glass/Epoxy Composite Plates (Glass/Epoxy 복합재료의 피로강도평가 및 피로수명예측)

  • 김정규;김도식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.10
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    • pp.2475-2482
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    • 1993
  • The effects of the hole size(2R) and the specimen width(W) on the fatigue strength and the fatigue life in plain woven glass/epoxy composite plates are experimentally investigated under constant amplitude tensile fatigue loading. It is shown in this study that the notch sensitivity under fatigue loading is lower than that under static loading. It can be explained by the fact that the stress concentration is relaxed by the damage developed at the boundary of circular hole. To predict the fatigue strength at a specific cycle, the modified point stress criterion represented as a function of the geometry of the specimen(2R and W) is applied. It is found that the model used in the prediction of the notched tensile strength predicts the fatigue strength with reasonable accuracy. A model for predicting the fatigue life in the notched specimen, based on the S-$N_f$, curve in the smooth specimen, is suggested.

Characteristics of Individual Growth Curve by Porcine LEPR-derived Microsatellite Polymorphisms (돼지의 Leptin receptor 유전자내 초위성체 다형성에 따른 개체별 성장곡선 특성)

  • Cho, Y.M.;Choi, B.H.;Kim, T.H.;Lee, J.W.;Cheong, I.C.
    • Journal of Animal Science and Technology
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    • v.45 no.6
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    • pp.885-890
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    • 2003
  • This study was conducted to estimate the growth curve parameters of 253 heads of F2 population produced by inter-crossing F1 from Korean Native boars and Landrace sows, and to estimate the effects of Leptin receptor gene(LEPR) on their growth characteristics. Growth curve parameters were estimated from nonlinear regression using Gompertz model individually. Average mature weight and average maturing rate estimated were 179.69${\pm}$4.40kg and 0.3103${\pm}$0.0043, respectively. The effect of sex was insignificant for all the parameters estimated from Gempertz model(p〉.05), and the effect of calving group was significant for mature weight and maximum growth rate at inflection point (p〈.05). The effect of LEPR genotype were significant for all the growth curve parameters(p〈.05). According from the results of the least squares means of growth curve parameters by LEPR genotypes, mature weight and point of inflection were highest in genotype AA in which the maturing rate was the lowest, and were lowest in genotype DD in which maturing rate was the highest, reversely.

Dyeability of Nylon Fabrics with Dyestuff for Supercritical Fluid Dyeing (1) : C.I. Disperse Red 167, C.I. Disperse Violet 93 (초임계 유체 염색용 염료에 따른 Nylon 섬유의 염색 특성 (1) : C.I. Disperse Red 167, C.I. Disperse Violet 93 Azo계 염료)

  • Choi, Hyunseuk;Park, Shin;Kim, Taeyoung
    • Textile Coloration and Finishing
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    • v.32 no.4
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    • pp.217-225
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    • 2020
  • In this study, the dyeing characteristics of nylon fabric which is dyed with supercritical fluid were investigated. There were two dyes used in the dyeing experiment: C.I. Disperse Red 167 and C.I. Disperse Violet 93. Dyeing temperature, pressure, and leveling time were fixed at 110℃, 250bar, 60minutes, and the experiment was conducted with dyeing concentration of 0.1, 0.3, 0.5, and 0.85% o.w.f. The analysis of the experimental results was found out through the measurement of washing fastness and color coordinate. In addition, the calibration curve of each dye was drawn up and the amount of remaining dye was checked by measuring the absorbance of the residual dye. As a result of color difference measurement, as the concentration increased, the L⁎ value decreased and the K/S value increased. However, the increase in K/S value compared to the amount of input decreased as the concentration increased. The comparative experiment on the amount of residual dye(C.I. Disperse Red 167) in the pot showed that 99.14% of the amount was dyed at the concentration of 0.1% o.w.f, while it rapidly decreased to 77% at 0.85% o.w.f. C.I. Disperse Violet 93 dye also decreased from 0.5% o.w.f to 93.91%. In the washing fastness experiment of both dyes, the level of washing fastness began to decrease from samples dyed at 0.5% o.w.f. It may be because the simply absorbed dye was produced instead of completely being fixed in the amorphous region of the nylon fiber.

Research on the Applicability of Conventional p-y curve for Lateral Behavior of Pile Foundation based on Inverse Analysis (역해석기법에 의한 기존의 p-y곡선 적용성에 관한 고찰)

  • Kim, Hyun-Uk;Goh, Jae-Sin;Kim, Nam-Ho;Kim, Yeon-Jung
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.390-400
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    • 2010
  • BNWF(Beam on Nonlinear Winkler Foundation) method has long been adopted for lateral behavior analysis of pile foundation and widely recognized for its simplicity and accuracy up until now. However, due to lateral load tests which were done in limited conditions and theory-based input Parameter estimation, the applicbility of p-y curve has not been fully examined. Accordingly, we researched on the applicability of conventional input parameter estimation and the p-y curve to be determined by the estimation through inverse analysis based on lateral load tests.

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