• Title/Summary/Keyword: D.B.H. analysis

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Saturated Hydraulic Conductivity of Surface Seals Estimated from Computed Tomography-Measured Porosity (고해상도 X-ray CT 를 이용한 토양표면 피막의 공극율 및 포화수리전도도 측정)

  • Lee, Sang-Soo;Gantzer, C.J.;Thompson, A.L.;Anderson, S.H.;Ketchum, R.A.;Ok, Yong-Sik
    • 한국환경농학회:학술대회논문집
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    • 2011.07a
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    • pp.207-222
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    • 2011
  • Relationships between soil saturated hydraulic conductivity ($K_s$) and porosity (${\phi}$) have been developed over many years; however, use of these relationships for evaluating rain-induced seals is limited mainly because of difficulties in estimating seal pore-size characteristics. The objectives of this study were to evaluate the $K_s$ of soil surface seals over a range of thicknesses, where seal thickness was determined using a High-Resolution-Computed-Tomography (HRCT) scanner, and to investigate relationships between $K_s$ and ${\phi}$ of developing seals in samples with equivalent diameters (e.d.) ${\geq}15\;{\mu}m$. A Mexico silt loam soil was packed to a bulk density (${\rho}_b$) of $1.1\;Mg\;m^{-3}$ in cylinders 160-mm i.d. by 160-mm long and subjected to $61-mm\;h^{-1}$ simulated rainfall having a kinetic energy (KE) of $25\;J\;m^{-2}\;min^{-1}$ for 7.5, 15, 30, and 60 min to create a range in seal development. Thicknesses of the seal layers were determined by analysis of HRCT images of seals. The $K_s$ values of the seals were estimated using an effective $K_s$ value ($K_{s-eff}$). The $K_s-{\phi}$ relationship was described by a Kozeny and Carmen equation, $K_s=B{\phi}^n$; where B and n are empirical constants and n = 31. This approach explained 86% of the variation between $K_s$ and ${\phi}$ within the soil seals. Knowledge of surface seal information and hydraulic conductivity can provide useful information to use in management of sites prone to sealing formation.

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Analysis of microstructure and texture evolution in AZ31Mg alloy fabricated by direct/indirect extrusion process (직/간접 압출공정에 의해 제조된 AZ31Mg 합금의 미세조직 및 집합조직 변화 분석)

  • Kim, D.H.;You, B.S.;Park, S.S.;Yoon, D.J.;Choi, S.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.10a
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    • pp.38-41
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    • 2008
  • To investigate the evolution of microstructure and texture in AZ31 Mg alloy, direct/indirect extrusion process was carried out at $300^{\circ}C$ with various extrusion speeds. The distribution of grain size depends on extrusion method and extrusion speed. More homogeneous grain site can be obtained at higher extrusion speed of indirect extrusion process. Extrusion speed does not affect significantly texture evolution during extrusion process regardless of extrusion method. ODF section is more useful to understand texture evolution during extrusion process compared with pole figure.

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Analysis of Permanent Magnet linear Eddy Current Brake (영구자석 선형 와전류 제동기의 특성해석)

  • Jang, S.M.;Lee, S.H.;Jeong, S.S.;Cha, S.D.;Cho, H.J.;Kim, B.S.
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1226-1228
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    • 2002
  • Permanent magnet is applied to the mover of eddy current braking system for high speed. On the analytical 2D field solutions considering end effect, this paper deals with the magnetic field, and forces according to the secondary magnet array. Comparisons between analytical results and experimental results are also presented.

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Design and Performance Analysis of A Parallel Digtal Signal Processing System (병렬 디지털신호처리시스템의 설계와 성능분석)

  • Moon, B.P.;Park, J.S.;Oh, D.S.;Jeon, C.H.;Park, S.J.;Lee, D.H.;Oh, W.C.;Han, K.T.
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10a
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    • pp.724-726
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    • 1998
  • 본 논문에서는 방대한 양의 데이터를 실시간으로 처리하기 위한 병렬 디지털 신호처리시스템을 제안한다. 버스와 메모리의 구조가 다른 네 가지 신호처리부 모델을 제안하고 그들의 성능을 분석한다. 신호처리부의 분석은 소나 알고리즘을 실행하는데 소요되는 하드웨어 지연시간과 버스 지연시간의 합을 척도로 한 성능 분석과 보드의 복잡도를 비교하는 방법을 통하여 이루어졌다. 성능분석한 결과, 지역 메모리와 공유 메모리를 함께 사용하는 모델이 가장 효율적인 것으로 나타났다.

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A Design on Test Facility for EMF Environment Analysis (전자계 환경분석을 위한 실증시스템 설계)

  • Cho, Y.G.;Myung, S.H.;Lee, J.B.;Chang, S.H.;Kim, J.D.;Lee, D.I.;Sin, G.Y.
    • Proceedings of the KIEE Conference
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    • 2003.10a
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    • pp.246-248
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    • 2003
  • 본 연구에서는 송배전선로의 기하학적 구조인 철탑형상 및 선로배치에 따른 자기장 특성을 규명할 수 있는 가변구조 형태의 전자계 실증시험장을 설계하였다. 이를 위해서는 수동/능동 시험장과 이외 여러 가지 자기장 저감 효과를 분석할 수 있는 복합시험장으로 구분될 필요가 있다. 이에 따라 본 설계에서는 2개의 시험장을 구성하는 것을 기본 방향으로 설정하여 구체적 설계방안을 검토하였다. 또한, 전자계 실종시험장에 사용될 전류원 설비를 설계 제작하여 안정적인 대전류원을 공급함으로써 신뢰성있는 실증시험 시스템이 되도록 설계하였다.

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Behavior of Large Sized Anchorage System under Shear Loads (직매형 대형매입앵커의 전단거동특성)

  • Kim, Kang-Sik;Kwon, Ki-Joo;Shin, Sung-Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.87-88
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    • 2009
  • In this research project, 24 tests are performed to find out a behavior and shear breakout capacity of large anchor system exceeding 2 inch(50mm) in anchor bolt diameter($d_0$) and 25 inch(635mm) in effective embedment($h_{ef}$) not addressed by ACI 349-01 Appendix B (ACI 349 2001). On this report, analysis results are presented that this variables influence on behavior and shear breakout strength through those of test results.

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A Study on the Analysis of Conductor Temperature Distribution of Underground Power Cables Buried in Ducts (관로부설 지중 전력 케이블 도체 온도 해석에 관한 연구)

  • Jeong, Seong-Hwan;Kim, D.K.;Choi, S.B.;Lee, D.I.;Kang, J.W.;Kim, H.S.;Park, J.H.
    • Proceedings of the KIEE Conference
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    • 2001.05a
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    • pp.270-272
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    • 2001
  • This paper proposes an algorithm of analyzing the conductor temperature distribution of underground power cables buried ill ducts. This algorithm used an equation of the permissible current-carrying capability of power cables. The algorithm will be given to an operator an ability to operate the underground power system in comfort.

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Acceleration Test of Ion Migration for PCB Electronic Reliability Evaluation (PCB 전기적 신뢰성평가를 위한 이온 마이그레이션 가속시험)

  • Lee, D.B.;Kim, J.H.;Kang, S.K.;Chang, S.W.;Lim, J.H.;Ryu, D.S.
    • Journal of Power System Engineering
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    • v.9 no.1
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    • pp.64-69
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    • 2005
  • In evaluation of electronic reliability on the PCB(Print Circuit Borad),electrochemical migration is one of main test objects. The phenomenon of electrochemical migration occurs in the environment of the hight humidity and the hight temperature under bias through a continuous aqueous electrolyte. In this paper, the generating mechanism of electrochemical migration is investigated by using water drop acceleration test under various waters. The waters used in the water drop test are city water, distilled water and ionic water. It found that the generated velocity of electrochemical migration depended on electrolyte quantity which included in the various waters.

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Analysis of Airflow Characteristics in an Enclosed Nursery Pig House (무창자돈사의 공기유동 특성 분석)

  • Song, Jun-Ik;Choi, H.L.;Yang, C.B.;Kim, H.T.
    • Journal of Animal Science and Technology
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    • v.47 no.1
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    • pp.107-114
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    • 2005
  • Experiments were carried out to evaluate the air speed distribution of an enclosed nursery pig bay in summer and winter. The data taken by experiments were compared to validate with the calculated air speeds by a commercial CFD code, FLUENT. Air basically enters into the bay through perforated circular ducts overhanged on the ceiling, leaves through a exhaust fan attached on the end-wall of the bay. Air speeds were measured as 2 ${\sim}$ 2.5 mls at the perforated holes in the duct in winter and 7 mls in summer. The validation showed that a CFD simulaton is one of feasible methods to predict airspeed distribution in the nursery pig bay.