• Title/Summary/Keyword: Effective porosity

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Evaluation of Oil Infiltration Behavior in Porous Media Using Dielectric Response (유전율에 의한 지반 매질내 유류침투거동 분석)

  • Kim Man-Il;Jeong Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.15 no.1
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    • pp.29-39
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    • 2005
  • For detecting a ground contamination survey, soil sampling method have been used a drilling or coring technique in general. However these methods are very difficult to systematically real-time monitoring of variation of contamination degree in field. ]'n this research frequency Domain Reflectometry (FDR) system was suggested and carried out to experimental approaches for determination of oil contamination on surface and underground. Experimental method using FDR method was discussed with feasibility of measurement in the laboratory column test. It is determined to degree of oil contamination due to response of dielectric constant re-lated with volumetric water content(θ/sub w/) and volumetric oil content( θ/sub al/ ) of saturated and unsaturated soil media. And physical properties such as effective porosity and oil residual ratio of saturated soil media were also measured through real-time monitoring works using installed FDR measurement sensors, which are defected characteristics of oil movement in the saturated soil media under the soil column tests. In the results of these experiments, a range of effective porosity was estimated to about 0.35 compared with initial porosity 0.40 of manufactured saturated soil media, which is also calculated to about 87.5% to the ratio of initial porosity to effective porosity. Finally oil residual ratio which is compared with volumetric water content and volumetric oil content was calculated about 62.5%.

Electrical Resistivity at Room Temperature and Relation between Physical Properties of Core Samples from Ulleung Island (울릉도 시추 코어의 상온 전기비저항과 물성 간의 상관성)

  • Lee, Tae Jong;Lee, Sang Kyu;Yun, Kwan-Hee
    • Geophysics and Geophysical Exploration
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    • v.18 no.4
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    • pp.171-180
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    • 2015
  • Electrical resistivity of 23 core samples from Ulleung Island at dry or saturated condition has been measured along with dry density and effective porosity, and the relations between the properties has also been discussed. Upper and lower bounds of electrical resistivity at room temperature can be provided by the dry- and saturated-resistivity, respectively. Injecting nitrogen gas to the pore space at the very end of drying process can prevent humid air from getting into the pore space, so that measurement of dry-resistivity can be less affected by humidity in the air. Dry density and porosity have very close correlation; the ratio between increase of porosity and the decrease of density showed distinct relation to the rock types, such that basaltic rocks showed higher ratio while trachytic rocks showed lower. Saturated resistivity showed close correlation to density and effective porosity of the rock sample, while dry resistivity didn't.

Effect of change in forest environment on water storage capacity in soil and streamflow (산림환경 변화가 토양내 수저유능력과 유출에 미치는 영향)

  • Nam, Yi;Park, Seung-Ki
    • Journal of Korea Soil Environment Society
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    • v.2 no.2
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    • pp.35-51
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    • 1997
  • 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 in Pyungchang, Kangwon-Do during 1983∼1993. Hydrological datas such as runoff, monthly ratio of runoff to precipitation, runoff-duration, monthly runoff(by plenty, ordinary, low and scanty duration), total runoff, direct runoff by runoff components, bulk density, porosity, coarse pore, fine pore, permeability and effective water storage were obtained from Backokpo and Yimokjong watersheds. The monthly ratio of runoff to precipitation, runoff and runoff-duration were higher in Yimokiong than in Backokpo due to forest type difference. On compararing pre-treatment with trement period in two experimental watersheds, pre-treatment period was lower than treatment period. Physical properties of soil such as bulk density, porosity, permeability, and effective water storage capacity conditions were better during the pre-trement period than treatment period in the two experiment plots.

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Empirical model to estimate the thermal conductivity of granite with various water contents (다양한 함수비를 가진 화강암의 열전도도 추정을 위한 실험적 모델)

  • Cho, Won-Jin;Kwon, Sang-Ki;Lee, Jae-Owan
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.8 no.2
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    • pp.135-142
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    • 2010
  • To obtain the input data for the design and long-term performance assessment of a high-level waste repository, the thermal conductivities of several granite rocks which were taken from the rock cores from the declined borehole were measured. The thermal conductivities of granite were measured under the different conditions of water content to investigate the effects of the water content on the thermal conductivity. A simple empirical correlation was proposed to predict the thermal conductivity of granite as a function of effective porosity and water content which can be measured with relative ease while neglecting the possible effects of mineralogy, structure and anisotropy. The correlation could predict the thermal conductivity of granite with the effective porosity below 2.7% from the KURT site with an estimated error below 10%.

Clay adsorptive membranes for chromium removal from water

  • Kashaninia, Fatemeh;Rezaie, Hamid Reza;Sarpoolaky, Hossein
    • Membrane and Water Treatment
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    • v.10 no.4
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    • pp.259-264
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    • 2019
  • Cost effective clay adsorptive microfiltration membranes were synthesized to remove Cr (III) from high polluted water. Raw and calcined bentonite were mixed in order to decrease the shrinkage and also increase the porosity; then, 20 wt% of carbonate was added and the samples, named B (without carbonate) and B-Ca20 (with 20 wt% calcium carbonate) were uniaxially pressed and after sufficient drying, fired at $1100^{\circ}C$ for 3 hours. Then, physical and mechanical properties of the samples, their phase analyses and microstructure and also their ability for Cr(III) removal from high polluted water (including 1000 ppm Cr (III) ions) were studied. Results showed that the addition of calcium carbonate lead the porosity to increase to 33.5% while contrary to organic pore formers like starch, due to the formation of wollastonite, the mechanical strength not only didn't collapse but also improved to 36.77 MPa. Besides, sample B-Ca20, due to the presence of wollastonite and anorthite, could remove 99.97% of Cr (III) ions. Hence, a very economic and cost effective combination of membrane filtration and adsorption technology was achieved for water treatment which made microfiltration membranes act even better than nanofiltration ones without using any adsorptive nano particles.

Pharmaceutical Potential of Gelatin as a pH-responsive Porogen for Manufacturing Porous Poly(d,l-lactic-co-glycolic acid) Microspheres

  • Kim, Hyun-Uk;Park, Hong-Il;Lee, Ju-Ho;Lee, Eun-Seong;Oh, Kyung-Taek;Yoon, Jeong-Hyun;Park, Eun-Seok;Lee, Kang-Choon;Youn, Yu-Seok
    • Journal of Pharmaceutical Investigation
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    • v.40 no.4
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    • pp.245-250
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    • 2010
  • Porous poly(lactic-co-glycolic acid) microspheres (PLGA MS) have been utilized as an inhalation delivery system and a matrix scaffold system for tissue engineering. Here, gelatin (type A) is introduced as an extractable pH-responsive porogen, which is capable of controlling the porosity and pore size of PLGA microspheres. Porous PLGA microspheres were prepared by a water-in-oil-in-water ($w_1/o/w_2$) double emulsification/solvent evaporation method. The surface morphology of these microspheres was examined by varying pH (2.0~11.0) of water phases, using scanning electron microscopy (SEM). Also, their porosity and pore size were monitored by altering acidification time (1~5 h) using a phosphoric acid solution. Results showed that the pore-forming capability of gelatin was optimized at pH 5.0, and that the surface pore-formation was not significantly observed at pHs of < 4.0 or > 8.0. This was attributable to the balance between gel-formation by electrostatic repulsion and dissolution of gelatin. The appropriate time-selection between PLGA hardening and gelatin-washing out was considered as a second significant factor to control the porosity. Delaying the acidification time to ~5 h after emulsification was clearly effective to make pores in the microspheres. This finding suggests that the porosity and pore size of porous microspheres using gelatin can be significantly controlled depending on water phase pH and gelatin-removal time. The results obtained in this study would provide valuable pharmaceutical information to prepare porous PLGA MS, which is required to control the porosity.

Fabrication of Porous SiC Ceramics by Partial Sintering and their Properties (부분소결공정에 의한 다공질 탄화규소 세라믹스의 제조 및 특성)

  • 김신한;김영욱;윤중열;김해두
    • Journal of the Korean Ceramic Society
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    • v.41 no.7
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    • pp.541-547
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    • 2004
  • Addition of large particles restrains densification by small particles in mixed particle systems. In the present study, large SiC whiskers or particles were introduced into small particles for restraining densification and the mixtures were sintered using yttrium aluminum garnet (Y$_3$A1$\sub$5/O$\sub$12/, YAG) as a sintering additive. By controlling the content of large SiC whiskers or particles and the applied pressure during sintering, porous SiC ceramics, with a porosity ranging from 0.3% to 39%, were fabricated. Porosity increased with increasing the content of restraining materials. SiC whiskers were more effective than large SiC partcles for restraining densification. Permeability of the porous SiC ceramics increased with increasing the porosity. Flexural strength decreased with increasing porosity. A noticeable increase in strain to failure was observed in the porous ceramics with a porosity ranging from 18% to 39%.

Shear correction factors of a new exponential functionally graded porous beams

  • Mohammed Sid Ahmed Houari;Aicha Bessaim;Tarek Merzouki;AhmedAmine Daikh;Aman Garg;Abdelouahed Tounsi;Mohamed A. Eltaher;Mohamed-Ouejdi Belarbi
    • Structural Engineering and Mechanics
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    • v.89 no.1
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    • pp.1-11
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    • 2024
  • This article introduces a novel analytical model for examining the impact of porosity on shear correction factors (SCFs) in functionally graded porous beams (FGPB). The study employs uneven and logarithmic-uneven modified porosity-dependent power-law functions, which are distributed throughout the thickness of the FGP beams. Additionally, a modified exponential-power law function is used to estimate the effective mechanical properties of functionally graded porous beams. The correction factor plays a crucial role in this analysis as it appears as a coefficient in the expression for the transverse shear stress resultant. It compensatesfor the assumption that the shear strain is uniform across the depth of the cross-section. By applying the energy equivalence principle, a general expression for static SCFs in FGPBs is derived. The resulting expression aligns with the findings obtained from Reissner's analysis, particularly when transitioning from the two-dimensional case (plate) to the one-dimensional case (beam). The article presents a convenient algebraic form of the solution and provides new case studies to demonstrate the practicality of the proposed formulation. Numerical results are also presented to illustrate the influence of porosity distribution on SCFs for different types of FGPBs. Furthermore, the article validates the numerical consistency of the mechanical property changesin FG beams without porosity and the SCF by comparing them with available results.

Effective Estimation of Porosity and Fluid Saturation using Joint Inversion Result of Seismic and Electromagnetic Data (탄성파탐사와 전자탐사 자료의 복합역산 결과를 이용한 효과적인 공극률 및 유체포화율의 추정)

  • Jeong, Soocheol;Seol, Soon Jee;Byun, Joongmoo
    • Geophysics and Geophysical Exploration
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    • v.18 no.2
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    • pp.54-63
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    • 2015
  • Petrophysical parameters such as porosity and fluid saturation which provide useful information for reservoir characterization could be estimated by rock physics model (RPM) using seismic velocity and resistivity. Therefore, accurate P-wave velocity and resistivity information have to be obtained for successful estimation of the petrophysical parameters. Compared with the individual inversion of electromagnetic (EM) or seismic data, the joint inversion using both EM and seismic data together can reduce the uncertainty and gives the opportunity to use the advantages of each data. Thus, more reliable petrophysical properties could be estimated through the joint inversion. In this paper, for the successful estimation of petrophysical parameters, we proposed an effective method which applies a grid-search method to find the porosity and fluid saturation. The relations of porosity and fluid saturation with P-wave velocity and resistivity were expressed by using RPM and the improved resistivity distribution used to this study was obtained by joint inversion of seismic and EM data. When the proposed method was applied to the synthetic data which were simulated for subsea reservoir exploration, reliable petrophysical parameters were obtained. The results indicate that the proposed method can be applied for detecting a reservoir and calculating the accurate oil and gas reserves.

Sintered Metal Wicks Development for the High Performance Loop Heat Pipe(LHP) Systems

  • Choi, Jee-Hoon;Sung, Byung-Ho;Yoo, Jung-Hyun;Seo, Min-Whan;Kim, Chul-Ju
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2136-2141
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    • 2007
  • The Loop Heat Pipe(LHP) system uses capillary forces so as to pump the working fluid from heat acquisition to heat rejecting systems. The performance of the LHP systems depends mainly upon the operating performance of the wick structure. The capillary pressure increases with decreasing the pore size of the wick structure. By the way, the wick structure's permeability decreases with decreasing the pore size and the porosity. To obtain an ideal wick, the wick structure should possess several characteristics such as the small pore size, high porosity and chemical compatibility with working fluid. Sintered metal wicks have been mainly used as the capillary wick structure mounted in LHP because of the fact that the sintered metal wick has some advantages like convenient selection of wick material, smaller pore size and so on as well as high reliability. In this study, sintered metal wicks were developed to meet required several parameters to design the high performance LHP systems for obtaining even more effective cooling technologies.

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