• Title/Summary/Keyword: K-ratio method

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Settlement prediction for footings based on stress history from VS measurements

  • Cho, Hyung Ik;Kim, Han Saem;Sun, Chang-Guk;Kim, Dong Soo
    • Geomechanics and Engineering
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    • v.20 no.5
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    • pp.371-384
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    • 2020
  • A settlement prediction method based on shear wave velocity measurements and soil nonlinearity was recently developed and verified by means of centrifuge tests. However, the method was only applicable to heavily overconsolidated soil deposits under enlarged yield surfaces. In this study, the settlement evaluation method was refined to consider the stress history of the sublayer, based on an overconsolidation ratio evaluation technique, and thereby incorporate irrecoverable plastic deformation in the settlement calculation. A relationship between the small-strain shear modulus and overconsolidation ratio, which can be determined from laboratory tests, was adopted to describe the stress history of the subsurface. Based on the overconsolidation ratio determined, the value of an empirical coefficient that reflects the effect of plastic deformation over the elastic region is determined by comparing the overconsolidation ratio with the stress increment transmitted by the surface design load. The refined method that incorporate this empirical coefficient was successfully validated by means of centrifuge tests, even under normally consolidated loading conditions.

Photoluminescence property of ZnO nanoparticle prepared by microwave irradiation method

  • Sakamoto, Naonori;Ishizuka, Satoshi;Wakiya, Naoki;Suzuki, Hisao
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.788-791
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    • 2008
  • ZnO nanoparticle was successfully prepared by microwave irradiation method in various oxygen/nitrogen ratio atmospheres. The product prepared in a low oxygen ratio atmosphere showed tetra pod shape with high aspect ratio, c/a. PL spectra of the products showed higher UV emission intensity than the others when it was prepared in the atmosphere oxygen/nitrogen=40/60.

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Analysis of plane frame structure using base force element method

  • Peng, Yijiang;Bai, Yaqiong;Guo, Qing
    • Structural Engineering and Mechanics
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    • v.62 no.1
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    • pp.11-20
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    • 2017
  • The base force element method (BFEM) is a new finite element method. In this paper, a degenerated 4-mid-node plane element from concave polygonal element of BFEM was proposed. The performance of this quadrilateral element with 4 mid-edge nodes in the BFEM on complementary energy principle is studied. Four examples of linear elastic analysis for plane frame structure are presented. The influence of aspect ratio of the element is analyzed. The feasibility of the 4 mid-edge node element model of BFEM on complementary energy principles researched for plane frame problems. The results using the BFEM are compared with corresponding analytical solutions and those obtained from the standard displacement finite element method. It is revealed that the BFEM has better performance compared to the displacement model in the case of large aspect ratio.

Development of the Bias-Cut Dress Pattern Making Method by Applying Fabric Draping Ratio

  • Park, Chan-Ho;Chun, Jong-Suk
    • The Research Journal of the Costume Culture
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    • v.20 no.4
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    • pp.594-603
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    • 2012
  • This study aimed to investigate a bias pattern making method with geometrical approach. The bias-cut dress has soft silhouette of drape in the garment. However, the bias cut dress has problem of satisfying the intended garment size spec. This problem occurs from various sources. The main reason is that the bias-cut fabric tends to stretch on longitudinal direction and to shrink horizontal direction when it was hung on the body. The goal of this study was to develop a bias-cut dress pattern making method satisfying the intended garment size spec. The researchers developed the geometrical method of measuring dimensional change by calculating the compensation ratio of the fabric in true bias direction. The compensation ratio was calculated by applying draping ratio of the fabric. Three types of fabrics were used in the experiment. The warp and weft crossing angle of fabric was ranged from $78^{\circ}$ to $82^{\circ}$. The fabrics stretched longitudinally 6.9~9.9% and shrank horizontally 7.2~11.0%. The compensation ratio of the bias-cut pattern for sample dress was calculated for each fabric type. Two types of experimental bias-cut dress patterns were developed for each fabric. One pattern was made with applying full compensation ratio and the other one made with applying partial ratio of the fabric. Experimental dresses were made with these patterns. The results of the evaluation showed that the bias-cut dress pattern applying the partial compensation ratio was more appropriate than the pattern applying the full compensation ratio.

Decal Method with High Catalyst Transfer Ratio and Its Performance in PEMFC

  • Park, Hyun-Seo;Cho, Yong-Hun;Cho, Yoon-Hwan;Sung, Yung-Eun
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.169-171
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    • 2007
  • A breaking layer was introduced to conventional decal transfer method in membrane electrolyte assembly fabrication for high catalyst transfer ratio. In this study, the modified decal transfer method with high catalyst transfer ratio was introduced and its performance is studied. The structural features of electrodes made by decal method were investigated using scanning electron microscopy and current-voltage polarization measurement.

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A Study on Sensibility Measurement Method

  • Kwon, Kyu-Sik;Kim, Sun-Woong
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 2000.04a
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    • pp.426-430
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    • 2000
  • This study is about the human sensibility measurement method. Researches on human sensibility measurement have been performed in many aspects. However, due to the subtlety and intricacy of human sensibility, it has been difficult to exactly measure human sensibility.At present, Semantic Differential(SD) method is most widely used to quantify human sensibility. In SD method, complicate human sensibility is represented on a scale with equal interval or equal ratio. However, this method has a critical problem in that human sensibility cannot be expressed with equal interval or equal ratio.In order to complement SD method and represent human sensibilities appropriately, we proposed an alternative method using the chroma-scale with saturation that had not equal interval or ratio. In experiment, proposed method shown that subjects understood a new scale easily and they could express their sensibilities on a new scale without any limitation. As a result, the chroma-scale can be used not only for measuring consumer's preference but also for evaluating or selecting sensibility words.

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An Iterative Algorithm to Estimate LIDAR Ratio for Thin Cirrus Cloud over Aerosol Layer

  • Wang, Zhenzhu;Liu, Dong;Xie, Chenbo;Zhou, Jun
    • Journal of the Optical Society of Korea
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    • v.15 no.3
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    • pp.209-215
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    • 2011
  • A new iterative algorithm is developed to estimate LIDAR ratio for a thin cirrus cloud over an aerosol layer. First, the thin cirrus cloud is screened out and replaced by a modeled LIDAR signal and the extinction coefficients of the aerosol layer are derived using the Fernald backward method. These aerosol coefficients are referred as the "actual values". Second, the original LIDAR signal which includes the thin cirrus cloud is also inverted by the Fernald backward method down to the aerosol layer but using different LIDAR ratio for the thin cirrus cloud. Depending on the different assumptions about the LIDAR ratio of the thin cirrus cloud, different sets of aerosol extinction can be derived. The "actual values" which are found in the first step can be used to constrain this iterative progress and the correct LIDAR ratio of the thin cirrus cloud can be found. The detailed description of this method and retrieval examples are given in the paper. The cases compared with other methods are presented and the statistical result is also shown and agrees well with other studies.

A study on method for improving renewable energy supply ratio for the school building applied PV system (태양광발전 시스템이 설치된 학교건물의 신재생에너지 공급비율 증가방안에 관한 연구)

  • Kim, Seok-Hyun;Lee, Yong-Ho;Hwang, Jung-Ha;Cho, Young-Hum
    • Journal of the Korean Solar Energy Society
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    • v.33 no.2
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    • pp.42-49
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    • 2013
  • Recently, the attention to renewable energy has increased globally because of the environmental issue and the global energy crisis. Accordingly, south korea is focused on increasing the renewable energy usage. And the government enforced a law to the public buildings to install the renewable energy facilities. In this study, the building to evaluate renewable energy consumption and supply ratio was selected. This building has 9.79% of renewable energy supply ratio by PV system. In this study, the method for improving renewable energy supply ratio was analyzed using additional PV system. And The 5 methods to increasing electricity were evaluated. The method of increase 4.24 times PV arrays area is most efficient way to increase the renewable supply ratio. The case 1, show that the increasing renewable energy supply ratio of 39.2% compared to exsiting PV system. The result of the above, consider the additional supply of renewable energy.

Effect of coarse aggregates and sand contents on workability and static stability of self-compacting concrete

  • Mohamed, Sahraoui;Taye, Bouziani
    • Advances in concrete construction
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    • v.7 no.2
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    • pp.97-105
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    • 2019
  • In this paper, the workability and static stability were evaluated using a proposed test method. Workability and static stability represent a key property of self-compacting concrete (SCC) in fresh state. A number of standardized test methods were developed to assess these properties. However, no accelerated test method reliably predicts both workability and static stability of SCC. In the present work, a modified K-slump test method was developed to evaluate workability and static stability of SCC. In order to take implicit mixture variations of SCC constituents that can affect fresh SCC properties, a central composite design was adopted to highlight the effect of gravel to sand ratio (G/S), gravel 3/8 to gravel 8/15 ratio (G1/G2), water to cement ratio (W/C), marble powder to cement ratio (MP/C) and superplasticizer content (SP) on workability measured with slump and flow time (T50) tests and static stability measured with sieve stability test (Pi), segregation test index (SSI), Penetration test (Pd) and the proposed K-slump test (Km). The obtained results show that G/S ratio close to 1 and G1/G2 ratio close to 60% can be considered as optimal values to achieve a good workability while ensuring a sufficient static stability of SCC. Acceptable relationships were obtained between Slump flow, Pi, Pd and Km. Results show that the proposed K-slump test allow to assess both workability and static stability of fresh SCC mixtures.

Direct Duty Ratio Pulse Width Modulation Method for Matrix Converters

  • Li, Yulong;Choi, Nam-Sup;Han, Byung-Moon;Kim, Kyoung-Min;Lee, Buhm;Park, Jun-Hyub
    • International Journal of Control, Automation, and Systems
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    • v.6 no.5
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    • pp.660-669
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    • 2008
  • This paper presents a new carrier based pulse-width modulation (PWM) method for matrix converters. By using the concept of average over one switching period, the modulation algorithm and the required equations are derived to synthesize the desired output voltage and to achieve the controlled input power factor. The proposed method uses a continuous carrier and the predetermined duty ratio signals to directly generate the gating signals and, thus, is referred to as "direct duty ratio PWM (DDPWM)". The feasibility and validity of the proposed method were verified by simulation and experiment.