• Title, Summary, Keyword: Filled Water

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New 3D failure analysis of water-filled karst cave beneath deep tunnel

  • Zhang, R.;Yang, X.L.
    • Geomechanics and Engineering
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    • v.18 no.1
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    • pp.1-9
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    • 2019
  • In this study, both 2D and 3D failure shapes of rock mass above the water-filled cavity are put forward when the surrounding rock mass cannot bear the pressure caused by the water-filled cavity. Based on the analytical expressions derived by kinematic approach, the profiles of active and passive failure patterns are plotted. The sensitivity analysis is conducted to explore the influences of different rock parameters on the failure profiles. During the excavation of the deep tunnels above the karst cavity, the water table always changes because of progressive failure of cavity roof. Therefore, it is meaningful to discuss the effects of varying water level on the failure patterns of horizontal rock layers. The changing laws of the scope of the failure pattern obtained in this work show good consistency with the fact, which could be used to provide a guide in engineering.

A Similarity of the Velocity Profiles According to Water Depth in Partially Filled Circular Pipe Flows (비만관 상태의 원형관로에서 수위에 따른 속도분포의 상사성)

  • Yoon, Ji-In;Kim, Young-Bae;Sung, Jae-Yong;Lee, Myeong-Ho
    • Journal of the Korean Society of Visualization
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    • v.6 no.2
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    • pp.28-32
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    • 2008
  • Contrary to the flow rate in fully filled pipe flows, the flow rate in partially filled pipe flows is significantly influenced by the variation of water level, channel slop, and so on. The major difference in these two flows results from the existence of a free surface. To make it clear, in the present study, a similarity of the velocity profile in a partially filled circular pipe has been investigated according to the water level. A particle image velocimetry (PIV) technique was applied to measure the three-dimensional velocity profiles. As a result, there is found a similarity of the velocity profile near the central region. However, near the side wall, the similarity is broken due to the interaction between the wall and the free surface.

Mathematical Simulation for the Prediction of the Shelf Life of Tofu Packaged in a Polyethylene Container (폴리에틸렌 필름으로 포장된 두부의 보관수명 예측을 위한 수치모사)

  • Kim, Jai Neung;Rim, Byung-O;Shon, Tae-Won;Chung, Gui-Yung
    • Applied Chemistry for Engineering
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    • v.9 no.6
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    • pp.889-893
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    • 1998
  • In this research, mathematical models for predicting the shelf life of packaged tofu in a polyethylene container were developed. Transfer of oxygen in air through the package and then diffusion of oxygen into the filled water and the tofu with the simultaneous oxygen consumption by micoorganisms were studied. The results of simulation showed that the increase of microorganisms in the filled water was more than that in tofu. As a result, it turns out that the shelf life of packaged tofu was not determined by the number of microorganisms in the tofu, but by that in the filled water. Additionally, the effects of physical properties of packaging material and packaged materials, such as the oxygen permeability of packaging material, oxygen diffusion coefficient and the initial oxygen concentration in filled water, and the depth of the filled water, on the shelf life of packaged tofu, were observed.

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Acoustic Characteristics of Sand Sediment Slab with Water- and Air-filled Pore

  • Roh Heui-Seol;Lee Kang Il;Yoon Suk Wang
    • Proceedings of the Acoustical Society of Korea Conference
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    • pp.223-226
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    • 2001
  • Acoustic pressure transmission coefficient and phase velocity are measured as the functions of water porosity and air porosity in sand sediment slabs with water- and air-filled pores. Pores in the sand sediment slab we modeled as the structure of circular cylindrical tube shape filled with water and air. The first kind(fast) wave and second kind (slow) wave, identified by Biot, in the solid and fluid mixed medium are affected by the presence of water and air pores. Acoustic characteristics of such porous medium in water are also theoretically investigated in terms of the modified Biot-Attenborough (MBA) model, which uses the separate treatment of viscosity effect and thermal effect in non-rigid porous medium with water- and air-filed pores. The information on the fast waves introduces new concepts of the generalized tortuosity factor and dynamic shape factor.

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Dynamic Behavior Analysis of Stiffened Cylindrical Shell Filled with Fluid (내부가 유체로 채워진 보강원통쉘의 동적거동 해석)

  • Youm, Ki-Un;Yoon, Kyung-Ho;Lee, Young-Shin;Kim, Jong-Kiun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.9
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    • pp.2875-2886
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    • 1996
  • This work present the experimental resutls for the free vibration of unstiffened, stiffened cylindrical shell filled with air, half water and full water. The natural frequencies and mode shapes of unstiffened, stiffened cylindrical shell are obtained experimentally also. The natural frequencies of stiffened cylindrical shell were generally highter than those of unstiffened cylindrical shell and natural requencies were decreased as cylindrical shell was filled with water. The effect of circumferential stiffener in the first mode was shown that natural frequency more increased 25% at air environment, 29% at half water environment and 37% at full water than those of unstiffened cylindrical shell, respectively. Also, the natural frequencies were decreased according to the added mass effect of fluid in the shell of unstiffened and stiffened cylindrical shell. The six mode shape results of all cases are simular and given. The natural frequencies are determined for a wide range of parameters : e.g. unstiffened shell, and filled with air, half and full water. The effects of varying the parameters on the free vibration frequencies and mode shapes are discussed.

Analytical solution of seismic stability against overturning for a rock slope with water-filled tension crack

  • Zhang, Yanjun;Nian, Tingkai;Zheng, Defeng;Zheng, Lu
    • Geomechanics and Engineering
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    • v.11 no.4
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    • pp.457-469
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    • 2016
  • Steep rock slope with water-filled tension crack will happen to overturn around the toe of the slope under seismic loading. This failure type is completely different from the common toppling failure occurring in anti-dipping layered rock mass slopes with steeply dipping discontinuities. This paper presents an analytical approach to determine the seismic factor of safety against overturning for an intact rock mass slope with water-filled tension crack considering horizontal and vertical seismic coefficients. This solution is a generalized explicit expression and is derived using the moment equilibrium approach. A numerical program based on discontinuous deformation analysis (DDA) is adopted to validate the analytical results. The parametric study is carried out to adequately investigate the effect of horizontal and vertical seismic coefficients on the overall stability against overturning for a saturated rock slope under two water pressure modes. The analytical results show that vertically upward seismic inertia force or/and second water pressure distribution mode will remarkably decrease the slope stability against overturning. Finally, several representative design charts of slopes also are presented for the practical application.

Highly filled AIN/epoxy composites for microelectronic encapsulation (반도체 봉지용 고충진 AIN/Epoxy 복합재료)

  • 배종우;김원호;황영훈
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.131-134
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    • 2000
  • Increased temperature adversely affects the reliability of a device. So, package material should have high thermal diffusion, i.e., high thermal conductivity. And, there are several other physical properties of polymeric materials that are important to microelectronics packaging, some of which are a low dielectric constant, a low coefficient of thermal expansion (CTE), and a high flexural strength. In this study, to get practical maximum packing fraction of AIN (granular type) filled EMC, the properties such as the spiral flow, thermal conductivity, CTE, and water resistance of AIN-filled EMC (65-vol%) were evaluated according to the size of AIN and the filler-size distribution. Also, physical properties of AIN filled EMC above 65-vol% were evaluated according to increasing AIN content at the point of maximum packing fraction (highly loading condition). The high loading conditions of EMC were set $D_L/D_S$=12 and $X_S$=0.25 like as filler of sphere shape and the AIN filled EMC in this conditions can be obtained satisfactory fluidity up to 70-vol%. As a result, the AIN filled EMC (70-vol%) at high loading condition showed improved thermal conductivity (about 6 W/m-K), dielectric constant (2.0~3.0), CTE(less than 14 ppm/$^{\circ}C$) and water resistance. So, the AIN filled EMC (70-vol%) at high loading condition meets the requirement fur advanced microelectronic packaging materials.

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The Effects of Warm Water-Filled Bag on Body Temperature, $FiO_2$, Respiration Rate, and Blood Sugar in High Risk Neonates (물주머니를 이용한 가온요법이 고위험신생아의 체온과 산소요구도, 호흡수, 혈당에 미치는 효과)

  • Kim Hee Young;Park Ho Ran;Moon Young Im;Park Jin Hee
    • Child Health Nursing Research
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    • v.11 no.4
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    • pp.390-395
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    • 2005
  • Purpose: To investigate the effects of a warm water-filled bag on body temperature, Oxygen demand, respiratory rate and blood sugar in high risk neonates. Method: The infants were assigned to two groups, 16 in the experimental and 20 in the control group. Infants in the experimental group was received $40{\~}42^{\circ}C$ warm water-filled bag therapy for 2 hours under radiant warmers. Infants in the control group were placed under the same kind of radiant warmers but without the warm water-filled bag. The following were measured every 30 minutes: rectal temperature, $O_2$ demand ($FiO_2$), and respiratory rate. Blood sugar was measured hourly. Result: Body temperatures increased significantly in the experimental group (P=0.0138), and there was a difference according to time (P=0.0001). Significant difference were found between the two groups fur $FiO_2$ (P=0.0180). There was no difference in respiratory rates between the two groups and rates according to time for the experimental group were also not significant (P=0.3569). No significant difference between two groups was found for blood sugar (P=0.2152), but there was a significant difference according to the times (P=0.0001). Conclusion: This results of this study indicate that a warm-filled bag is an effective means of resorting body temperature and reducing $O_2$ demand in high risk neonates.

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Influence of reinforcing systems and microstructures of SBR on water swelling behaviors of SBR composites (충전 시스템과 SBR의 미세 구조가 SBR 복합체의 수팽윤 거동에 미치는 영향)

  • Choi, Sung-Seen;Ha, Sung-Ho
    • Elastomers and Composites
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    • v.42 no.2
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    • pp.102-106
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    • 2007
  • Water swelling behaviors of SBR vulcanizates with different reinforcing systems of carbon black, silica without a coupling agent, and silica containing a coupling agent were studied. Distilled water and 3.5% NaCl solution were used as swelling media. The water swelling ratios in the distilled water were higher than those in the salt solution. The water swelling ratios of the carbon black-filled samples were lower than those of the silica-filled ones. For the silica-filled SBR vulcanizates, the specimens without the silane coupling agent had higher water swelling ratios than those containing it. Water swelling behaviors of SBR composites with different 1,2-unit contents were also compared. The water swelling ratios tended to decrease by increasing the 1,2-unit content.

Preparation and Water Quality Purification of Permeable Concrete Pavement Filled with Microbial-Soil Sheet (미생물토양시트를 충진한 도로포장용 다공성 콘크리트의 제조 및 수질정화특성)

  • Kang, Young-Heoun;Hwang, Pil-Gi;Kang, Seon-Hong
    • Journal of Korean Society of Water and Wastewater
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    • v.23 no.6
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    • pp.727-733
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    • 2009
  • This study was performed to investigate the physical characteristics like compressive strength, permeability, porosity and the water quality removal characteristics of permeable concrete pavement filled with microbial-soil sheet to remove SS, organic matter and nutrients in artificial rainfall. As a result, it can show the removal efficiency is SS 90~95%, COD 85~93%, BOD 80~83%, T-N 61~75%, T-P 71~78% on WAPS I(W1) and WAPS II(W2). Therefore, permeable concrete pavement filled with microbial-soil sheet shows higher removal efficiency(SS 10%, organic matter and nutrients 30%) than a conventional porous concrete(W3). By filling microbial-soil sheet to permeable concrete pavement, we confirm that the function and efficiency are improved significantly and that a naturally-friendly facility can be developed and applied to treat non-point sources.