• Title/Summary/Keyword: Univ. of Texas

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Comparative Drought Resistances among Eleven Warm-Season Turfgrasses and Associated Plant Parameters

  • Kim, Ki Sun;Beard, James B.
    • Weed & Turfgrass Science
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    • v.7 no.3
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    • pp.239-245
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    • 2018
  • Comparative drought resistances of 11 perennial warm-season turfgrasses were evaluated in the field after withholding irrigation for 48 days in summer I and 57 days in summer II. There were significant variations among the grasses in their drought resistances. From two years study of field shoot recovery from drought stress, the relative rankings among the 11 warm-season turfgrasses was as follows. 'Arizona Common' and 'Texturf 10' bermudagrasses [Cynodon dactylon (L.) Pers.], 'Tifgreen' hybrid bermudagrass [C. dactylon (L.) Pers. ${\times}$ C. transvaalensis Davy], and 'Georgia Common' centipedegrass [Eremochloa ophiuroides (Munro.) Mack.] possessed good drought resistances, whereas 'Texas Common' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and 'Tifway' hybrid bermudagrass [Cyndon dactylon (L.) Pers ${\times}$ C. transvaalensis Davy] possessed poor drought resistances. 'Texas Common' buffalograss [Buchloe dactyloides (Nutt.) Engelm.], 'Pensacola' bahiagrass (Paspalum notatum Flugge.), and 'Adalayd' seashore paspalum (Paspalum vaginatum Swartz), 'Meyer' zoysiagrass (Zoysia japonica Steud.), 'Emerald' zoysiagrass (Z. japonica Steud. ${\times}$ Z. tenuifolia Willd. ex Trin.) were found to rank intermediate. Visual leaf firing showed the highest correlation (r=-0.84) to shoot recovery from drought stress. Visual leaf rolling (r=-0.59) and canopy-air temperature differential (r=-0.64) also showed very significant correlations, whereas leaf water potential (r=0.54) showed relatively lower correlation.

The Effects of Processing Variables on Gas Penetration in Gas-Assisted Powder Injection Molding(GAPIM) (가스분말사출성형에서 공정조건 변화가 중공부 형성에 미치는 영향)

  • Kim, D.H.;Park, H.P.;Lee, K.H.;Cha, B.S.;Choi, J.H.;Rhee, B.O.;Tovar, Jorge A.
    • Transactions of Materials Processing
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    • v.21 no.2
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    • pp.107-112
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    • 2012
  • Gas-assisted injection molding(GAIM) produces parts with hollow internal sections. The technique offers benefits to powder injection molding(PIM), with lower material usage and reduced time for de-binding processes. In this study, the effects of processing parameters on gas penetration length of gas-assisted powder injection molding(GAPIM) were investigated for SUS316L stainless steel powder feedstock. Experiments were planned based on the Taguchi method, involving processing variables such as melt temperature, shot size, gas pressure, and gas delay time. The most significant parameters affecting gas penetration length were gas delay time and shot size, while the effects of melt temperature and gas pressure was relatively insignificant.

CASE STUDY: CONSTRUCTION LITIGATION FOR THE U.S. NAVAL FACILITIES ENGINEERING COMMAND, 1995-2004

  • Lilin Liang;G. Edward Gibson Jr.
    • International conference on construction engineering and project management
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    • 2005.10a
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    • pp.693-698
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    • 2005
  • Evaluation of construction claims history can provide insights to improvement opportunities in a capital project portfolio. This study analyzed construction litigation claims extracted from the U.S. Court of Federal Claims (COFC) history involving the U.S. Naval Facilities Engineering Command (NAVFAC) from 1995-2004. Twenty-four total cases were examined over this period. Both "primary" causes and "root" causes were identified and compared to 666 litigation cases reviewed by the Armed Services Board of Contract Appeals (ASBCA). Based on the analysis, strategies for resolving future disputes are recommend using a 'hybrid' process prior to litigation.

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OPTIMIZATION OF WHEAT HARVEST

  • Kim, Sang-hun-;William-J.Kolaric;Kang, Whoa-Seug
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.714-726
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    • 1993
  • Optimization was considered from three perspectives ; minimum grain loss, minimum damaged grain loss, and minimum power consumption. Factors affecting combine performance were classified as control , adjustable , and environmental. Control and adjustable factors were optimized by the parameter design developed by Tajuchi. Environmental factors were used as input for optimization Optimum range for control and adjustable factors are presented. Parameter design was adequate to obtain the optimum levels of control factors and optimum range of adjustable factors.

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Compressed Channel Feedback for Correlated Massive MIMO Systems

  • Sim, Min Soo;Park, Jeonghun;Chae, Chan-Byoung;Heath, Robert W. Jr.
    • Journal of Communications and Networks
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    • v.18 no.1
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    • pp.95-104
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    • 2016
  • Massive multiple-input multiple-output (MIMO) is a promising approach for cellular communication due to its energy efficiency and high achievable data rate. These advantages, however, can be realized only when channel state information (CSI) is available at the transmitter. Since there are many antennas, CSI is too large to feed back without compression. To compress CSI, prior work has applied compressive sensing (CS) techniques and the fact that CSI can be sparsified. The adopted sparsifying bases fail, however, to reflect the spatial correlation and channel conditions or to be feasible in practice. In this paper, we propose a new sparsifying basis that reflects the long-term characteristics of the channel, and needs no change as long as the spatial correlation model does not change. We propose a new reconstruction algorithm for CS, and also suggest dimensionality reduction as a compression method. To feed back compressed CSI in practice, we propose a new codebook for the compressed channel quantization assuming no other-cell interference. Numerical results confirm that the proposed channel feedback mechanisms show better performance in point-to-point (single-user) and point-to-multi-point (multi-user) scenarios.

Damage Detection in Jacket-Type Offshore Structures From Few Mode Shapes (소수의 모드형상을 이용한 자켓형 해양구조물의 손상추정에 대한 연구)

  • Kim, Jeng-Tae;;Stubbs, Norris
    • Journal of Ocean Engineering and Technology
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    • v.8 no.1
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    • pp.144-153
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    • 1994
  • An algorithm to locate and estimate severity of damage in jacket-type offshore structures for which modal responses are availabit' for very few vibrational modes is presented. First, a theory of damage locaization and severity estimation(which yields information on the location and severity of damage directly from changes in mode shapes) is formulated. Next, the feasibility the damage detection algorithm is demonstrated by using a numerical example of an offshore jacket platform for which only three vibration modes are measured. Form the material presented here, two major results are observed. First, all damage locations in the offshore jacket platform are correctly predicted. Next, predicted damage is relatively correctly estimated.

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ALMA observations of a proto-binary system, IRAS 04191+1523

  • Lee, Jeong-Eun;Lee, Seokho;Yoon, Sung-Yong;Dunham, Michael;Evans, Neal;Choi, Minho;Tatematsu, Ken;Bergin, Edwin
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.46.4-47
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    • 2016
  • About 50% of stars reside in binary or multiple systems. However, the formation mechanism of the multiplicity is poorly understood. Theoretical studies suggest two main mechanisms for the multiplicity: turbulent fragmentation and disk fragmentation. We can testify which mechanism is more plausible by measuring the separation between companions or the alignment of stellar spins. Here we present our ALMA Cycle 2 observational results of a proto-binary system, IRAS 04191+1523, which consists of two Class I sources. We detected disks around both Class I sources, which are located in a common dense filamentary structure traced by $C^{18}O$ J=2-1. Two protostellar disks are separated by ~900 AU and their rotational axes are almost perpendicular, which strongly support that this binary system formed by the turbulent fragmentation.

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