• Title/Summary/Keyword: Saturated velocity

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Continuous Cocurrent Extraction of Milk Fat by Supercritical Carbon Dioxide (초임계이산화탄소에 의한 유지방의 연속 병류식 추출)

  • Lim, Sang-Bin;Syed S.H.Rizvi
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.3
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    • pp.459-465
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    • 1994
  • Performance of a continuous cocurrent supercritical fluid extraction column for processing of anhydrous milk fat (AMF) was determined. The extract loading increased and the extraction yield decreased as the superficial velocity of AMF increased. The maximum solubility of AMF in $CO_2$ at 4$0^{\circ}C$/3,500 psig was 0.0195g/g. The increase of the carbon dioxide density enhanced the solubility of milk fat and decreased the cholesterol concentration in the extract. Three operation conditions, such as recycle , reflux, and temperature gradient of extraction column, were tested. More short-chain fatty acvids were extracted by the reflux operation . Longchain fatty acids and thehighest ratio fo long-chain unsaturated to saturated fatty acids were also obtained in the raffinate phase with refluex.

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Identification of the Shear Velocities of Near Surface Soils Using Torsional Guided Waves (비틀림 유도파를 이용한 근지표면 전단속도 규명)

  • Park, Kyung-Jo;Oh, Hyung-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.8
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    • pp.771-776
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    • 2012
  • A technique is presented that uses a circular waveguide for the measurement of the bulk shear(S-wave) velocities of unconsolidated, saturated media, with particular application to near surface soils. The technique requires the measurement of the attenuation characteristics of the fumdamental T(0,1) mode that propagates along an embedded pipe, from which the acoustic properties of the surrounding medium are inferred. From the dispersion curve analysis, the feasibility of using T(0,1) mode which is non-dispersive and have constant attenuation over all frequency range is discussed. The principles behind the technique are discussed and the results of an experimental laboratory validation are presented. The experimental data are best fitted for the different depths of wetted sand and the shear velocities as a function of depths are formulated using power law curves.

Ultrasonic flushing 기법에 의한 유류오염토양의 복원에 관한 실험연구

  • Jeong, Ha-Ik;Oh, In-Gyu;Kim, Sang-Geun;Lee, Yong-Su;Yoo, Jun
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.04a
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    • pp.13-17
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    • 2002
  • Ultrasonic waves have several mechanical, chemical, and biological effects on a saturated soil medium. Their mechanical effects, popularly known as cavitation. Cavitation is the rapid and repeated formation, and resulting implosion, of imcrobubbles in a liquid, resulting in the propagation of microscopic shock waves. In a soil-liquid system, their mechanical effects generate high differntial fluid-particle velocities and microscopic shock waves. The velocity perturbations are capable of dislodging oil in the system by overcoming the forces binding oil to sand particles. In this study, a series of laboratory experiments involving the simple flushing and ultrasonic flushing were carried out. An increase in permeability and oil removal rate were observed in ultrasonic flushing tests. Some practical implications of these results are discussed in terms of technical feasibility of in situ implementation of ultrasonics.

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Measurements of Droplet Sizes and Velocities with Optimum Probability Density Function in a Transient Liquefied Butane Spray (액상부탄 간헐분무의 액적 크기 및 속도 측정과 최적 확률분포 연구)

  • Kim, J.H.;Kim, J.W.;Koo, J.Y.
    • Journal of ILASS-Korea
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    • v.5 no.1
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    • pp.30-40
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    • 2000
  • The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a kind of flash boiling spray is expected when the back pressure is below the saturated vapor pressure of the butane(0.23MPa at 298K). The ambient pressure was held at a pressure above(0.37MPa) and below(0.15MPa) the fuel vapor pressure. The axial velocities, radial velocities, and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. The PDPA measurement showed a smaller SMD at the 0.15MPa chamber pressure, compared to the 0.37MPa case. Log-hyperbolic density function for the droplets size distribution can be fitted to the experimental results of a liquefied butane spray.

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1 D contaminant transport through unsaturated stratified media using EFGM

  • Rupali, S.;Sawant, Vishwas A.
    • Advances in environmental research
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    • v.8 no.1
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    • pp.1-21
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    • 2019
  • In the present study, analysis of contaminant transport through one dimensional unsaturated stratified media using element free Galerkin method has been presented. Element free Galerkin method is a meshfree method. A FORTRAN code has been developed for the same. The developed model is compared with the results available in the literature and are found in good agreement. Further a parametric study has been conducted to examine the effects of various parameters like velocity, dispersivity, retardation factor and effect of saturation on the contaminant flow. The results presented conclude that transport of contaminant is retarded in unsaturated zone in comparison with the saturated zone.

Analysis on Superconducting Electrodynamic Suspension for Very High Speed Maglev (초고속 자기부상열차를 위한 초전도 반발식 자기부상 특성 해석)

  • Bae, Duck-Kweon;Lee, Jong-Min;Cho, Han-Wook;Han, Hyung-Suk
    • Proceedings of the KIEE Conference
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    • 2009.04b
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    • pp.198-200
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    • 2009
  • This paper presents the numerical simulation results on the moving type electrodynamic suspension (EDS) simulator. Superconducting EDS system is generated by the interaction between the magnetic field made by the induced the eddy current in the ground conductor and the moving magnetic field made by onboard superconducting magnet. The levitation force of EDS system, which is proportional to the strength of the moving magnetic field, becomes saturated according to the increase of the velocity Especially, the levitation force is influenced by the structure of HTS magnet and ground conductor. The 3-D numerical analysis with FEM was used to find the distribution of the magnetic field, the optimal coil structure, and the calculation of the levitation force.

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Multi-Region Model of Solute Transport in Soil for the Preferential Flow (Preferential 흐름에 의한 토양내의 다영역 용질이동 모델)

  • 안병기
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.2
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    • pp.71-77
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    • 2000
  • A multi-region model for solute transport through saturated soils has been developed to describe preferential flow. The model consists of numerous discrete pore groups, which are characterized by a discrete dispersion coefficient, flow velocity, and porosity . The hydraulic properties for each pore group are derived from a soil's hydraluic conductivity and soil water characteristic functions . Flow in pore group is described by the classical advection-disersion equation (ADE). An implict finite difference scheme was applied to the governing equation that results in a block-tridiagonal system of equations that is very efficient and allows the soil to be divided into any number of pore groups. The numerical technique is derived from methods used to solve coupled equations in fluid dynamics problems and can also be applied to the transport of interacting solutes. The results of the model are compared to the experimental data from published papers. This paper contributes on the characteristics of the method when applied to the parallel porosity model to describe preferential flow of solutes in soil.

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Numerical Study of Convective Heat Transfer in an Inclined Porous Media (경사진 다공성물체내에서의 자연대류에 관한 수치해석)

  • Mok I. K.;Seo J. Y.;Kim C. B.
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.15 no.4
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    • pp.388-395
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    • 1986
  • Numerical solutions of two-dimensional, steady, and natural are investigated in a confined rectangular cavity with porous media. The saturated fluid is bounded by two isothermal vertical walls at different temperatures and two adiabatic horizontal walls. Governing equations are numerically solved by finite difference method with the up wind scheme. Distributions of streamline and temperature we. predicted for aspect ratios ranging from 0.1 to 1.0, Rayleigh numbers 50 to $10^4$, and tilt angles $0^{\circ}\;to\;60^{\circ}$. Representative plots of temperature and velocity field according to tilt angle are presented. The effects of aspect ratio, Rayleigh number, and tilt angle on local and average Nusselt numbers are obtained. The optimum conditions for maximum Nusselt number are also presented with tilt angles.

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Mapping the water table at the Cheongju-Gadeok site of the Korea National Groundwater Monitoring Network using multiple geophysical methods

  • Ju, Hyeon-Tae;Sa, Jin-Hyeon;Kim, Ji-Soo
    • The Journal of Engineering Geology
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    • v.27 no.3
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    • pp.305-312
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    • 2017
  • The most effective way to distinguish subsurface interfaces that produce various geophysical responses is through the integration of multiple geophysical methods, with each method detecting both a complementary and unique set of distinct physical properties relating to the subsurface. In this study, shallow seismic reflection (SSR) and ground penetrating radar (GPR) surveys were conducted at the Cheongju-Gadeok site of the Korea National Groundwater Monitoring Network to map the water table, which was measured at 12 m depth during the geophysical surveys. The water table proved to be a good target reflector in both datasets, as the abrupt transition from the overlying unsaturated weathered rock to the underlying saturated weathered rock yielded large acoustic impedance and dielectric constant contrasts. The two datasets were depth converted and integrated into a single section, with the SSR and GPR surveys conducted to ensure subsurface imaging at approximately the same wavelength. The GPR data provided detailed information on the upper ~15 m of the section, whereas the SSR data imaged structures at depths of 10-45 m. The integrated section thus captured the full depth coverage of the sandy clay, water table, weathered rock, soft rock, and hard rock structures, which correlated well with local drillcore and water table observations. Incorporation of these two geophysical datasets yielded a synthetic section that resembled a simplified aquifer model, with the best-fitting seismic velocity, dielectric constant, and porosity of the saturated weathered layer being $v_{seismic}=1000m/s$, ${\varepsilon}_r=16$, and ${\phi}=0.32$, respectively.

Utilization of Natural Zeolite for Removal of $NH_3$ Gas (($NH_3$ 가스 제거를 위한 천연 지오라이트의 이용)

  • Lee, Dong-Hoon;Choi, Jyung;Park, Moung-Sub
    • Korean Journal of Environmental Agriculture
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    • v.16 no.4
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    • pp.327-332
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    • 1997
  • This study was conducted to find out the effect for removal of $NH_3$ gas, one of the offensive odor. The removal efficiencies of $NH_3$ gas through zeolie column increased with the decreased percolation velocity. The effect of zeolite colum in removing $NH_3$ gas was influenced by the water content of zeolite and the added amount of zeolite, but was not influenced by the setting method of zeolite. The $NH_3$ gas removing sequence of saturated cation species on zeolite was in order of Ca->Na->$NH_4$ ->Natural->K-zeolite. Consequently the effect of zeolite on $NH_3$ gas removal efficiency is consided by the water content, added amount and saturated cation of the zeolite.

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