• Title/Summary/Keyword: Plane spacing

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Proposal of Plane Spacing Factor for Analyzing Air Void System in Concrete (콘크리트 공극 분석을 위한 평면간격계수의 제안)

  • Jeong, Won-Kyong;Choi, Sung-Yong;Kim, Sung-Hwan;Yun, Kyong-Ku
    • Journal of Industrial Technology
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    • v.25 no.A
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    • pp.39-47
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    • 2005
  • Air void systems in hardened concrete has an important influence on concrete durability such as freeze-thaw resistance, water permeability, surface scaling resistance. Linear traverse method and point count method described at ASTM are the routine analysis of the air void system that have been widely used to estimate the spacing factor in hardened concrete. Recently, many concretes often have a spacing factor higher than the generally accepted $200-250{\mu}m$ limit for the usual range of air contents. This study is proposed to estimate the plane spacing factor by calculation of simplicity. The plane spacing factor need two parameters that are air content and numbers of air voids in the hardened concrete. Those obtained from the standard air-void system analysis of the ASTM C 457. The equation is valid for all values of paste-to-air ratio because the estimation of paste content is unnecessary at the using ASTM C 457. The plane spacing factor yields a similar estimate of the standard spacing factor.

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Characteristics of Walls Supported by Prefabricated Strut (조립식 버팀보로 지지된 흙막이 구조물의 거동 특성에 관한 연구)

  • 김낙경;박종식
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.553-560
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    • 2003
  • From the analytical standpoint, it is advantageous to consider the behavior of supported walls as plane strain condition. But supported walls constitute geotechnical problems which, in strut terms, are not plane strain cases. These represent differences between the measured and the predicted due to the stiffness and spacing of supported walls and the behavior of discontinuous walls such as solider beams with lagging. This study is to investigate simulations of a system behavior along a horizontal section of walls supported by prefabricated strut. Using a beam column method, relative effects associated with prefabricated strut stiffness and spacing in a systematic behavior were investigated.

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Measurement of the discharge characteristics of liquid nitrogen at atmospheric pressure by personal computer system (컴퓨터 시스템에 의한 대기압하(大氣壓下)에서 액체질소($LN_2$)의 방전특성측정(放電特性測定))

  • Ju, Jae-Hyun;Lee, Young-Gun;Kim, Sang-Ku;Jeon, Young-Ju;Lee, Kwang-Sik;Lee, Dong-In
    • Proceedings of the KIEE Conference
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    • 1994.07b
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    • pp.1530-1532
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    • 1994
  • This paper describes the discharge characteristics of liquid nitrogen for plane-plane, needle-plane electrode at variation of gap spacing at atmospheric pressure. The important results obtained from this study are as follows. (1) Breakdown voltage of $LN_2$ for needle-plane electrode is higher than that of for plane-plane electrode and discharge duration tine is longer with increase of gap spacing at atmospheric pressure. (2) The formation of bubbles by evaporation is observed in spite of non-applying source at atmospheric pressure and the creation of corona confirmed for plane-plane electrode results from the bubbles. (3) The applied voltage-discharge magnitude( V-Q) characteristics of $LN_2$ showed hysteresis and the discharge magnitude decreasing and corona voltage increasing proportional to the pulse per second at atmospheric pressure.

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Quantification of Acoustic Pressure Estimation Error due to Sensor and Position Mismatch in Planar Acoustic Holography (평면 음향 홀로그래피에서 센서간 특성 차이와 측정 위치의 부정확성에 의한 음압 추정 오차의 정량화)

  • 남경욱;김양한
    • Journal of KSNVE
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    • v.8 no.6
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    • pp.1023-1029
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    • 1998
  • When one attempts to construct a hologram. one finds that there are many sources of measurement errors. These errors are even amplified if one predicts the pressures close to the sources. The pressure estimation errors depend on the following parameters: the measurement spacing on the hologram plane. the prediction spacing on the prediction plane. and the distance between the hologram and the prediction plane. This raper analyzes quantitatively the errors when these are distributed irregularly on the hologram plane The sensor mismatch and inaccurate measurement location. position mismatch. are mainly addressed. In these cases. one can assume that the measurement is a sample of many measurement events. The bias and random error are derived theoretically. Then the relationship between the random error amplification ratio and the parameters mentioned above is examined quantitatively in terms of energy.

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The Design of a K-Band 4$\times$4 Microstrip Patch Array Antennas with High Directitvity (고지향성 구현을 갖는 K-밴드 4$\times$4 마이크로스트립 패치 어레이 안테나의 설계)

  • Lee, Ha-Young;Kim, Hyeong-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.1
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    • pp.161-166
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    • 2007
  • In this paper, two 4$\times$4 rectangular patch array antennas operating at 20 GHz are implemented for the satellite communication. The sixteen patch antennas and microstrip feeding line are printed on a single-layered substrate. The design goal is to achieve high directivity and gain by optimizing design parameters through permutations in element spacing. The spacing between the array elements is chosen to be 0.736$\lambda$. Numerical simulation results indicate that the HPBW(Half-Power Beam Width) of the 4$\times$4 patch array antenna is 18.78 degrees in the E-plane and 18.48 degrees in the H-plane with a gain of 17.18 dBi. Numerical simulations of a 4$\times$4 recessed patch array antenna yield a HPBW of 18.71 degrees in the E-plane and 17.82 degrees in the H-plane with a gain of 19.43 dBi.

Evaluation for Rock Cleavage Using Distribution of Microcrack Spacings (II) (미세균열의 간격 분포를 이용한 결의 평가(II))

  • Park, Deok-Won
    • The Journal of the Petrological Society of Korea
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    • v.25 no.2
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    • pp.151-163
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    • 2016
  • The characteristics of the rock cleavage in Jurassic granite from Geochang were analysed. The evaluation for the three directions of rock cleavages was performed using the parameters such as (1) frequency of microcrack spacing(N), (2) total spacing(${\leq}1mm$), (3) mean spacing($S_{mean}$), (4) difference value($S_{mean}-S_{median}$) between mean spacing($S_{mean}$) and median spacing($S_{median}$), (5) density of spacing(${\rho}$), (6) difference value between two exponents for the whole range of the diagrams(${\lambda}_H-{\lambda}_L$), (7) mean value of exponent(${\lambda}_M$), (8) mean value of exponential constant($a_M$), (9) difference value between two exponents for the section under the initial points of intersection(${\lambda}t_H-{\lambda}t_L$), (10) mean value of exponent(${\lambda}t_M$) and (11) mean value of exponential constant($at_M$). The results of correlation analysis between the values of parameters for three rock cleavages and those for three planes are as follows. The values of (I) parameters(1, 2, 7 and 8) and (II) parameters(3, 4 and 5) are in orders of (I) H(hardway, (H1 + H2)/2) < G(grain, (G1 + G2)/2) < R(rift, (R1 + R2)/2) and (II) R < G < H. On the contrary, the values of the above two groups(I~II) of parameters for three planes show reverse orders. Besides, the values of parameter $6({\lambda}_H-{\lambda}_L)$, parameter $9({\lambda}t_H-{\lambda}t_L)$, parameter $10({\lambda}t_M)$ and parameter $11(at_M)$ for three planes are in orders of R(rift plane, (G1 + H2)/2) < H(hardway plane, (R2 + G2)/2) < G(grain plane, (R1 + H2)/2), H < G < R, H < R < G and R < H < G, respectively. The values of the above four parameters for three rock cleavages show the various orders of R < H < G, R < H < G, H < G < R and H < G < R, respectively. Meanwhile, the spacing values equivalent to the initial points of contact and intersection between the two directions of diagrams were derived. The above spacing values for three rock cleavages are in order of rift(R1 and R2) < grain(G1 and G2) < hardway(H1 and H2). The spacing values for three planes are in order of rift plane(G1 and H1) < hardway plane(R2 and G2) < grain plane(R1 and H2). In particular, the intersection angles for three rock cleavages and three planes are in order of rift and rift plane < hardway and hardway plane < grain and grain plane. Consequently, the two diagrams of rift(R1 and R2) and rift plane(G1 and H1) show higher frequency of the point of contact and intersection. These characteristics of change were derived through the general chart for three planes and three rock cleavages. Lastly, the correlation analysis through the values of parameters along with the distribution pattern is useful for discriminating three quarrying planes.

Simulation of Planted Area Index (PAI) for Crop Spacing Methods in Plant Factory (식물공장내 작물의 간격조절방법에 대한 식재면적지표 시뮬레이션)

  • Kim, Joon-Yong;Yang, Seung-Hwan;Lee, Chun-Gu;Ashtiani, A.A.;Rhee, Joong-Yong
    • Journal of Biosystems Engineering
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    • v.36 no.5
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    • pp.348-354
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    • 2011
  • Various crop spacing methods have been implemented so far for the greenhouse and plant factory applications. However, there is no generally accepted parameter for evaluation of plant spacing efficiency in plant production system. In this study, 'Planted Area Index' (PAI) of a spacing method is defined as the ratio of the planted area in the field to required planted area using the spacing method when no transplanting operation is assumed. Three common types of spacing methods for plane placement of the plants were modeled mathematically. For calculating the planted area, an optimal growth radius function (R(t)) is needed. Function of the days after transplanting stage gives a radius of an optimal circle area for the living plants. A computer simulation was developed to calculate the PAI, based on three crop spacing methods and four optimal growth radius functions. In general, the 1-D zigzag spacing showed the best PAI. Moreover, it gives an example on how to apply the PAI for the design.

A Study on the Measurements of Parameters Affecting the Breakdown Mechanism of a Large Air Spacing (이격거리가 큰 전극의 공기 절연파괴에 영향을 미치는 인자측정에 관한연구)

  • Cho, Yun-Ok;Choi, Young-Wook
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.756-760
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    • 1988
  • The paper presents the measurement results on the parameters affecting the breakdown mechanism of a large air spacing under switching impulse voltages. Measured parameters are the velocities of leader channels, predischarge currents, electric charges injected into the rod-plane air gap and electric field intensities on the plane. For the 3m air gap under switching impulse voltages, the velocities of leader channel have been measured to be of 1cm/${\mu}s$ - 5cm/${\mu}s$, electric field intensity of 2kv/cm, predischarge current of 1.2A - 1.6A, the charges injected into the air gap of 11 - 40 ${\mu}$C for 400-887kV impulse voltages.

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A Study on the Measurements of Discharge Parameters in Case of the Switching Impulse Breakdown of a Large Air Spacing (이격거리가 큰 전국의 공기절연파괴 현상시 발생하는 인자측정에 관한 연구)

  • 최영욱;조연옥
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.40 no.12
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    • pp.1290-1295
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    • 1991
  • The paper presents the measurement results on the parameters affecting the breakdown mechanism of a large air spacing under switching impulse voltages. Measured parameters are the velocities of leader channels, predischarge currents, electric charges injected into the rod-plane air gap and electric field intensities on the plane. For the 3m air gap under switching impulse voltages, the velocities of leader channel have been measured to be of 1cm/x10S0-6Ts - 5cm/x10S0-6Ts, electric field intensity of 2kv/cm, predischarge current of 1.2-1.6A, the charges injected into the air gap of 11-40x10S0-6TC for 400-887kV impulse voltages.

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Out-of-plane performance of infill masonry walls reinforced with post-compressed wedges under lateral-concentrated push load

  • Sanghee Kim;Ju-Hyun Mun;Jun-Ryeol Park;Keun-Hyeok Yang;Jae-Il Sim
    • Earthquakes and Structures
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    • v.26 no.6
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    • pp.489-499
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    • 2024
  • Infill masonry walls are vulnerable to lateral loads, including seismic, wind, and concentrated push loads. Various strengthening metal fittings have been proposed to improve lateral load resistance, particularly against seismic loads. This study introduces the use of post-compressed wedges as a novel reinforcement method for infill masonry walls to enhance lateral load resistance. The resistance of the infill masonry wall against lateral-concentrated push loads was assessed using an out-of-plane push-over test on specimens sized 2,300×2,410×190 mm3. The presence or absence of wedges and wedge spacing were set as variables. The push-over test results showed that both the unreinforced specimen and the specimen reinforced with 300 mm spaced wedges toppled, while the specimen reinforced with 100 mm spaced wedges remained upright. Peak loads were measured to be 0.74, 29.77, and 5.88 kN for unreinforced specimens and specimens reinforced with 100 mm and 300 mm spaced wedges, respectively. Notably, a tighter reinforcement spacing yielded a similar strength, as expected, which was attributed to the increased friction force between the masonry wall and steel frame. The W-series specimens exhibited a trend comparable to that of the displacement ductility ratio. Overall, the findings validate that post-compressed wedges improve the out-of-plane strength of infill masonry walls.