• Title, Summary, Keyword: Saturation Factor

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Saturation Depth and Slope Stability considering Unsteady Rainfall in Natural Slope (비정상강우를 적용한 자연사면에서의 포화깊이 산정 및 사면안정성 평가)

  • Kim, Sang-Hoon;Kim, Seong-Pil;Son, Young-Hwan;Heo, Joon;Chang, Pyoung-Wuck
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.1
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    • pp.57-65
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    • 2007
  • In Korea, most landslides occurr during the rainy season and have shallow failure planes parallel to the slope. For these types of rainfall-induced failures, the most important factor triggering slope unstability is decrease in the matric suction of unsaturated soils with increasing saturation depth by rainfall infiltration. For this reason, estimation of cumulative infiltration has a significance. In this study, infiltration rate and cumulative infiltration are estimated by using both Mein & Larson model based on Green-Ampt infiltration model and using modified Mein & Larson model to which unsteady rainfall is applied. According to the results, the modified model is more reasonable than Mein & Larson method itself in estimation of infiltration rate and saturation depth because of considering real pending condition.

Analytical Calculation for Predicting the Air Gap Flux Density in Surface-Mounted Permanent Magnet Synchronous Machine

  • Feng, Yan-li;Zhang, Cheng-ning
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.769-777
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    • 2017
  • The research of air gap flux density has a significant effect on predicting and optimizing the structure parameters of electrical machines. In the paper, the air gap coefficient, leakage flux factor and saturation coefficient are first analytically expressed in terms of motor properties and structure parameters. Subsequently, the analytical model of average air gap flux density for surface-mounted permanent magnet synchronous machines is proposed with considering slotting effect and saturation. In order to verify the accuracy of the proposed analytical model, the experiment and finite element analysis (FEA) are used. It shows that the analytical results keep consistency well with the experimental result and FEA results, and the errors between FEA results and analytical results are less than 5% for SPM with high power. Finally, the analytical model is applied to optimizing the motor structure parameters. The optimal results indicate that the analytical calculation model provides a great potential to the machine design and optimization.

Estimating Saturation-paste Electrical Conductivities of Rose-cultivated Soils from their Diluted Soil Extracts (절화장미 재배토양에서 희석된 토양 침출용액으로부터 포화반죽 전기전도도 추정)

  • Lee, In-Bog;Ro, Hee-Myong;Lim, Jae-Hyun;Yiem, Myoung-Soon
    • Korean Journal of Soil Science and Fertilizer
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    • v.33 no.6
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    • pp.398-404
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    • 2000
  • We examined the effect of soil:water ratio on the equivalent concentration of individual electrolyte species and the electrical conductivities (EC) of the diluted extracts of 24 soil samples (loam or silt loam) collected from rose-cultivated plastic houses to estimate the EC of saturated soil-paste extracts (ECe) from diluted soil extracts. With increasing volume ratio of water (higher dilution), the equivalent concentrations of each electrolyte species and their sum increased. The relative contribution to the EC, however, was highest for $NO_3{^-}$, irrespective of soil:water ratio. The measured ECe was 6.36 for loam and $8.09dS\;m^{-1}$ for silt loam soils and the corresponding soil:water ratio was 0.38 and 0.50, respectively. The EC_e estimated from the EC of diluted extracts at 1:1, 1:2, or 1:5 soil:water ratios using their corresponding uniform diluted factors was lower than the measured EC_e and this difference was greater with higher dilution and EC values. Therefore, the alternative diluted factors (y) for each soil: water ratio were obtained following the definition of diluted factor and were correlated significantly with volume ratios of added water (x): y=1.55x+0.5 for loam and y=1.21x+0.48 for silt loam soils. On the other hand, correlation analyses of the EC of soil extracts (y) to the volume ratio of added water (x) on log-log scale yielded linear models: logy = -0.805logx + logb, SD of slope=0.05, b=sample specific constant, n=24). With known saturation percentage of a sample representing a group and and the EC of diluted extract of a given soil, the EC_e could be predicted using the proposed logarithmic equation.

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A Study on Visual Characteristic & Evaluation of the Super Graphic of High-raised Apartment Housing (고층 아파트 외관 슈퍼그래픽의 시지각적 특성 및 평가 성향에 관한 연구)

  • 최석창;양소진;유창균;이청웅
    • Journal of the Korean housing association
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    • v.14 no.6
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    • pp.147-154
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    • 2003
  • This study examines and analyzes the current status, characteristics and properties of Super-Graphic as a visual element with Super Graphic designed on the wall of apartment housing, typifies them and explains the preference and evaluative structure by each type. The results of this study are as follows: According to color environment of Super-Graphic, N-tone colors are 21.4% and YR-tone colors are 14.5%. In the whole distribution, cold color tone is 41.4% and warm color tone is 37.2%. In the brightness, 72.9% of the entire Super Graphic use high brightness and in the saturation, 51.2% show low saturation, achromatic colors are 21.4% and high saturation is 16.5%. As a result of conducting SD test to analyze the preference of Super-Graphic, 'wonderful' is most negative variable, followed by 'heterogeneous', 'splendid', 'romantic' variety'. Positive variables are 'monotone', 'stable' and 'calm'. As a result of factor analysis to reveal the evaluative structure of Super Graphic image based on the above results, five factors including brightness, saturation, stability, harmony and ordered are extracted and it is considered that these are important variables to be reflected in designing Super Graphic in future.

Origin of the Initial Permeabiliy of Ni0.8-xZn0.2CoxFe2O4+δ Ferrite (Ni0.8-xZn0.2CoxFe2O4+δ조성 페라이트의 투자율 변화 기구)

  • 안용운;김종령;오영우
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.1
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    • pp.46-51
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    • 2004
  • The cause for the variation of the initial permeability according to the Co substitution of Ni-Zn ferrite used in the LC resonance filter for the power line communication is studied. The initial permeability decreases as the quantity of Co diminishes, and the saturation magnetization increases as the quantity increases. Because the sintering density and the microstructure of ferrite show little change, the variation of the initial permeability can't be explained by the density, microstructure nor the saturation magnetization factor. The magnetocrystalline anisotropy increases, similar with the saturation magnetization, as the quantity of Co increases. The increase of magnetocrystalline anisotropy value makes the domain wall energy grow, which leads to the decrease of the initial permeability, because there's linear law between the magnetocrystalline anisotropy and the domain wall energy. The resonance frequency to Co substitution moved to high frequency band, due to the close relationship with domain wall energy, Initial permeability decreaed a little with an increase of Co contents, but resonace frequency moved to high frequency band. as a result of that, when Co was added 0.05 mol, initial permeability and resonace frequency was 75 and 25 MHz respectively.

The Technique of Estimating the Right-Turn Adjustment Factor (우회전 보정계수 산정기법)

  • Kim, Gyeong-Hwan;Kim, Yeong
    • Journal of Korean Society of Transportation
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    • v.19 no.4
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    • pp.73-84
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    • 2001
  • Korean Highway Capacity Manual applies 7 adjustment factors to estimate saturation flows at signalized intersections. Among the adjustment factors, the right-turn adjustment factor uses equation hard to understand and requires complicated computing process comparing other adjustment factors. Thus. this study was conducted in order to suggest a new technique of estimating the right-turn adjustment factor which is easy to understand and simple to computer by having reasonable degree of accuracy. In this study the right-turn saturation flow ratios which are important in estimating the factor are suggested and the equation to estimate the volume of right-turn on red signal(RTOR) is developed based on observed data. The right-turn saturation flow rates can be estimated according to turning radius and number of lanes of crossing road dividing right-turn lanes into canalized and uncanalized lanes. The RTOR volume is estimated using the proportion of the time during which RTOR is possible to the whole time of red signal according to the through traffic volume per lane of the approach at signalized intersections. The technique of estimating the right-turn adjustment factor suggested in this study, which follows the HCM2000 of U.S. in principal, first judges the right-turn lane to be used exclusively for right-turn or not by employing the RTOR factor and the judging equation developed in this study. Next, if the right-turn lane is not exclusive right-turn lane, the shared right-turn lane is classified into single lane approach or multi lane approach. Thus, a total of three methods of estimating the right-turn adjustment factor to the three cases are suggested in this study.

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A study on the friction head loss in flat aluminum micro multi tubes with nonazeotropic refrigerant mixtures R-410A (비공비 혼합냉매 R-410A를 적용한 납작한 알루미늄 마이크로 멀티 튜브에서의 마찰손실에 관한 연구)

  • Lee, Jeong-Kun;Min, Kyung-Ho
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.13 no.2
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    • pp.37-43
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    • 2019
  • This study conducted a research as to condensation heat transfer friction loss headby using three types of flat micro multi-channel tubes with different processing of micro-fin and number of channels inside the pipes and different sizes of appearances. In addition, identical studies were conducted by using smoothing circular tubes with 5mm external diameter to study heat enhancement factor and pressure drop penalty factor. 1) The friction head loss showed an increase as the vapor quality and mass flux increased. In case of saturation temperature, it shows an increase as it gets lower. These factors are the reason occurring as the lower the saturation temperature is, the higher the density of refrigerant vapor gets. The influence of heat flux is similar as the dryness is low, but as it gets higher, it lowers in heat flux, and as the high temperature of high heat flux, it is a factor that occurs as the density gets lower. 2) RMS error of the in case of friction head loss, it showed to be predicted as 0.45~0.67 by Chisholm, Friedel, Lockhart and Martinelli. 3) As forfriction head loss penalty factor, the smaller the aspect ratio is, the larger the penalty factor gets, and as for the effect of micro-fin, the penalty factor increased because it decreases to the gas fluid the way groove for the refrigerant's flow.

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Phenomenological Nonlinear Gain Saturation Effect on the Noise Characteristics of a Multi-electrode DBR Laser with Continuous Frequency Tuning (연속 파장 가변시 현상론적인 비선형 이득포화효과가 다전극 DBR 레이저의 잡음특성에 미치는 영향)

  • 이석목;최원준;한일기;김회종;우덕하;김선호;이정일;감광남;박홍이
    • Korean Journal of Optics and Photonics
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    • v.6 no.2
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    • pp.135-141
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    • 1995
  • Phenomenological nonlinear gain saturation effect on the noise characteristics of a multi-electrode DBR laser, when the lasing wavelength changes continuously, is presented theoretically. Using the optical transmission line theory, noise characteristics reliant on output power are analyzed by taking into account both the spontaneous enhancement factor K due to the distribution of the spontaneous emission along the active cavity and the nonlinear gain saturation effect. Spontaneous emission rate was increased due to an increase in injected current into the passive section, which in turn lead to increase in relative intensity noise (RIN) and frequency noise. Phenomenological nonlinear gain saturation was found to have significant effect on RIN and frequency noise characteristics. However. Iinewidth was found to decrease due to a phenomenological nonlinear gain saturation effect. ffect.

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A Hydraulic Conductivity Model Considering the Infiltration Characteristics Near Saturation in Unsaturated Slopes (불포화 사면의 포화 부근 침투 특성을 고려한 수리전도도 모델)

  • Oh, Se-Boong;Park, Ki-Hun;Kim, Jun-Woo
    • Journal of the Korean Geotechnical Society
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    • v.30 no.1
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    • pp.37-47
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    • 2014
  • Unsaturated hydraulic conductivity (HC) is integrated theoretically from soil water retention curves (SWRC) by Mualem capillary model, but the prediction of HC is extremely sensitive to small variation of matric suction near saturation. Near saturation, the Mualem HC based on smooth SWRC decreases abruptly and has problems in the reliability of hydraulic behavior and the stability of numerical solutions. To improve van Genuchten-Mualem (VGM) HC, the van Genuchten SWRC model is modified within range of low matric suction (arbitrary air entry pressure). At an arbitrary air entry pressure, the VG SWRC is linearized in log scale until full saturation. The modified VG SWRC does not affect the fit of actual retention behavior and either the parameters of original VG SWRC fit. Using the modified VG SWRC, the VGM HC is modified to integrate for each interval decomposed by arbitrary air entry pressure. An analytical solution on modified VGM HC is proposed each interval, to protect the rapid change in HC near saturation. For silty soils, VGM models of HC function underestimate the unsaturated permeability characteristics and especially show rapid reduction near saturation. The modified VGM model predicts more accurate HC functions for Korean weathered soils. Furthermore, near saturation, the saturated HC is conserved by the modified VGM model. After 2-D infiltration analysis of an actual slope, the hydraulic behaviors are compared for VGM and the modified models. The prediction by the proposed model conserved the convergence of solutions on various rainfall conditions. However, the solution by VGM model did not converge since the conductivity near saturation reduced abruptly for heavy rainfall condition. Using VGM model, the factor of safety is overestimated in both initial and final stage during heavy rainfall. Stability analysis based on infiltration analysis could simulate the actual slope failure by the proposed model on HC.

An Optimal Design of High Space Factor BLDC Motor by Nonlinear Finite Element Method and Optimization Method (비선형 유한요소법과 최적화 기법을 이용한 고점적률 BLDC의 최적설계)

  • Oh, Seung-Kyun;Chung, Tae-Kyung;Jin, Yong-Sun
    • Proceedings of the KIEE Conference
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    • pp.388-390
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    • 1999
  • This paper discusses an optimal design of high space factor BLDC motor. Because of high space factor BLDC, Nonliear finite element method considering saturation of outer-rotor is used. For optimal design, a new niching genetic algorithm, namely "Restricted Competitions Selection" is used. This algorithm constructs an objective function using only the most important criteria and provides a designer with a set of solution rather than one solution. To verify its effectiveness, the new niching genetic algorithm is applied to an actual high space factor BLDC motor We show that a new designed high space factor BLDC motor is superior to the actual high space factor BLDC.

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