• Title/Summary/Keyword: Mixing rule

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Prediction of partial molar volumes of solutes in supercritical CO2 using the Peng-Robinson equation of state with various mixing rules and Kirkwood-Buff solution theory (3차 상태방정식과 여러 혼합법칙 및 Kirkwood-Buff용액이론을 이용한 초임계유체내에서의 용질의 무한희석 부분몰부피의 계산)

  • Jeon, Young-Pyo;Park, Jong-Seon;Kwon, Yong-Jung
    • Journal of Industrial Technology
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    • v.19
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    • pp.253-260
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    • 1999
  • Two thermodynamic models were used to predict the partial molar volumes of solutes in supercritical carbon dioxide at infinite dilution: (1) the Peng-Robinson equation of state with various mixing rules including those based on $EOS/G^E$ (2) the Kirkwood Buff fluctuation integral with the hard sphere expansion (HSE) method. The Kirkwood-Buff fluctuation integral method, in which an equation of state for pure component and molecular parameters are required, produced better results especially near the critical point than the Peng-Robinson equation of state with the several mixing rules based an $EOS/G^E$. When the $EOS/G^E$ mixing rules were used, poorer results were obtained compared with the classical mixing rule and Kirkwood-Buff model.

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The Variation Rate of Shear Modulus for Anisotropic Magneto-rheological Elastomer due to Volume Fraction of CIP (CIP 부피비에 따른 이방성 MRE의 전단계수 변화율)

  • Jeong, Un-Chang;Yoon, Ji-Hyun;Yang, In-Hyung;Lee, You-Yub;Oh, Jae-Eung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.12
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    • pp.1132-1137
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    • 2011
  • MRE(magneto-rheological elastomers) is a material which shows reversible and various modulus in magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb vibration of broader frequency range. These characteristic phenomena result from the orientation of magnetic particles named carbonyl iron powder(CIP) in rubber matrix. In this paper, simulation on variation rate of shear modulus for anisotropic MRE due to volume fraction of CIP and an effective permeability model was applied to predict the field-induced shear modulus of MREs. Also, the variation rate of shear modulus for anisotropic MRE was derived using magneto-mechanical theory. Based on Maxwell-Garnett mixing rule, the increment of shear modulus was calculated to evaluate the shear modulus of MREs with column structure of CIP due to induced current. The simulation results on variation rate of shear modulus can be applied to the variable mechanical system of MRE such as tunable vibration absorber, stiffness variable bush and mount.

Thermodynamic Empirical Equations for Physical Properties of Inert Gas Mixtures (불활성 기체 혼합물의 물성에 관한 열역학적 실험식)

  • 김재덕;여미순;이윤우;노경호
    • Fire Science and Engineering
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    • v.17 no.2
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    • pp.43-49
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    • 2003
  • For the inert gases of Ar, $N_2$and $CO_2$, the empirical equations of the gas mixture were correlated in terms of saturated pressure, density and viscosity. They were obtained by regression analysis based on the mixing rule. The empirical equation of saturated pressure was assumed as the first order function of temperature. The empirical form of density was expressed as compressibility factor and saturated pressure while the empirical equation of viscosity was formulated as a power function of temperature. This empirical equations of the physical properties were obtained in the composition of Ar, $N_2$and $CO_2$, 40/50/10(mol. %).

Development of an Automatic Nutrient-Solution Supply System Using Fuzzy Control (퍼지제어를 이용한 양액 자동공급 시스템 개발)

  • 황호준;류관희;조성인;이규철;김기영
    • Journal of Biosystems Engineering
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    • v.23 no.4
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    • pp.365-372
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    • 1998
  • This study was carried out to develop a nutrient-solution mixing-and-supplying system, which used a low-cost metering device instead of expensive metering pumps and a fuzzy logic controller. A low cost and precise overflow-type metering device was developed and evaluated by testing the flow discharge for the automatic nutrient-solution mixing-and-supplying system for snail-scale hydroponic sewers. The fuzzy logic controllers, which could predict and meet the desired values of EC and supply rate of nutrient solution were developed and verified by simulation and experiment. this fuzzy logic controller, whose algorithm consists of four crisp inputs, two crisp outputs and nine rules, was developed to predict the desired value of EC and supply rate of nutrient solution and two crisp inputs, one crisp output and nine rules used to control EC to the desired values. The nutrient-solution mixing-and-supplying system showed satisfactory EC control performance with the maximum overshooting of 0.035 mS/cm and the maximum settling time of 15 minutes in case of increasing 0.7 mS/cm. also, the accuracy of the overflow-type metering device in terms of the full-scale error was 2.29% when using solenoid valve only and 0.2% when using solenoid valve and flow control valve together.

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A STUDY ON THE SPEECH SYNTHESIS-BY-RULE SYSTEM APPLIED MULTIBAND EXCITATION SIGNAL

  • Kyung, Younjeong;Kim, Geesoon;Lee, Hwangsoo;Lee, Yanghee
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1994.06a
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    • pp.1098-1103
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    • 1994
  • In this paper, we design and implement the Korean speech synthesis by rule system. This system is applied the multiband excitation signal on voiced sounds. The multiband excitation signal is obtained by mixing impluse spectrum and which noise spectrum. We find that the quality of synthesized speech is improved using this application. Also, we classify the voiced sounds by cepstral euclidian distance measure for reducing overhead memory. The representative excitation signal of the same group's voiced sounds is used as excitation signal on synthesis. This method does not affect the quality of synthesized speech. As the result of experiment, this method eliminates the "buzziness" of synthesized speech and reduces the spectral distortion of synthesized speech.ed speech.

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Effects of Fracture Intersection Characteristics on Transport in Three-Dimensional Fracture Networks

  • Park, Young-Jin;Lee, Kang-Kun
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2001.09a
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    • pp.27-30
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    • 2001
  • Flow and transport at fracture intersections, and their effects on network scale transport, are investigated in three-dimensional random fracture networks. Fracture intersection mixing rules complete mixing and streamline routing are defined in terms of fluxes normal to the intersection line between two fractures. By analyzing flow statistics and particle transfer probabilities distributed along fracture intersections, it is shown that for various network structures with power law size distributions of fractures, the choice of intersection mixing rule makes comparatively little difference in the overall simulated solute migration patterns. The occurrence and effects of local flows around an intersection (local flow cells) are emphasized. Transport simulations at fracture intersections indicate that local flow circulations can arise from variability within the hydraulic head distribution along intersections, and from the internal no flow condition along fracture boundaries. These local flow cells act as an effective mechanism to enhance the nondiffusive breakthrough tailing often observed in discrete fracture networks. It is shown that such non-Fickian (anomalous) solute transport can be accounted for by considering only advective transport, in the framework of a continuous time random walk model. To clarify the effect of forest environmental changes (forest type difference and clearcut) on water storage capacity in soil and stream flow, watershed had been investigated.

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Study on the Prediction of Pressure Drop for Alternative Refrigerants with lubricant in Micro-Fin Tubes (미세휜관내 윤활유를 포함한 대체냉매의 압력강하 예측에 관한 연구)

  • Choi, Jun-Y.;Lee, Jin-Ho
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.83-89
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    • 2000
  • This paper presents a pressure drop correlation for evaporation and condensation of alternative refrigerant with oil in micro-fin tubes. The correlation was developed from a data base consisting of oil-free pure and mixed refrigerants in micro-fin tube; Rl25 R134a. R32 R410a(R32/R125 50/50% mass), R22, R407c(R32/R125/R134a, 23/25/52% mass) and R32/R134a(25/75% mass). The micro-fin tube used in this paper had 60 0.2mm high fins with a 18 helix angle. The cross sectional flow area $(A_c)$ was $60.8 mm^2$ giving an equivalent smooth diameter$(D_e)$ of 8.8mm. The hydraulic diameter $(D_h)$ was estimated to the 5.45mm. The new correlation was obtained by replacing the friction factor and the tube-diameter in Bo Pierre correlation by a friction factor derived from pressure drop data for a micro-fin tube and the hydraulic diameter, respectively. This correlation was also used to predict some pressure data with a lubricant after using a mixing viscosity rule of lubricants and refrigerants. As a result, the new correlation was also well predicted to the measured data within a mean deviation of 19.0%.

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Microwave Dielectric Characteristics of Aluminum Magnesium Tantalate Solid Solutions with Variations of Ionic Polarizability and Crystal Structure (이온 분극률과 결정구조에 따른 Aluminum Magnesium Tantalate 고용체의 마이크로파 유전특성)

  • 최지원;하종윤;강종윤;윤석진;윤기현;김현재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.119-122
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    • 2002
  • The calculated and measured dielectric constant of (1-x)(Al$\sub$1/2/Ta$\sub$1/2/)O$_2$-x(Mg$\sub$1/3/Ta$\sub$2/3/)O$_2$(O$\leq$x$\leq$1.0) solid solutions were investigated by variations of ionic polarizability and crystal structure. (Al$\sub$1/2/Ta$\sub$1/2/)O$_2$ and (Mg$\sub$1/3/Ta$\sub$2/3/)O$_2$were orthorhombic and tetragonal trirutile structure, respectively. When (Al$\sub$1/2/Ta$\sub$1/2/)O$_2$ was substituted by (Mg$\sub$1/3/Ta$\sub$2/3/)O$_2$, the phase transformed to tetragonal structure over 60 mole%. Because the ionic radius of (Mg$\sub$1/3/Ta$\sub$2/3/)O$_2$was slightly bigger than one of (A1$\sub$1/2/Ta$\sub$1/2)O$_2$, the cell parameters increased with an increase of (Mg$\sub$1/3/Ta$\sub$2/3/)O$_2$ substitution. The measured dielectric constant increased with an increase of (Mg$\sub$1/3/Ta$\sub$2/3/)O$_2$ substitution and coincided with dielectric mixing rule and the calculated dielectric constant with the molecular additivity rule. There were some differences between the measured and the calculated dielectric constant. The reason of the lowered dielectric constant comparing with the calculated one was compressed stress due to the electronic structure of tantalum.

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