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Zai Q. Yang, Yong X. Li, Xiao P. Xue, Chuan R. Huang, and Bo Zhang

. Richardson (1993) measured the wind load on a single-span film plastic-clad livestock building. Wang et al. (2008) analyzed the wind pressure distribution on a multispan plastic greenhouse, the results indicated that the wind pressure coefficients of open

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William R. Graves, Robert J. Joly, and Michael N. Dana

Honey locust (Gleditsia triacanthos var. inermis Wind.) and tree-of-heaven Ailanthus altissima (Mill.) Swingle] sometimes are exposed to high root-zone temperatures in urban microclimates. The objective of this study was to test the hypothesis that seedlings of these species differ in how elevated root-zone temperature affects growth, leaf water relations, and root hydraulic properties. Shoot extension, leaf area, root: shoot ratio, and root and shoot dry weights were less for tree-of-heaven grown with the root zone at 34C than for those with root zones at 24C. Tree-of-heaven with roots at 34C had a lower mean transpiration rate (E) than those grown at 24C, but leaf water potential (ψ1) was similar at both temperatures. In contrast, shoot extension of seedlings of honey locust grown with roots at 34C was greater than honey locust at 24C, E was similar at both temperatures, and ψ1 was reduced at 34C. Hydraulic properties of root systems grown at both temperatures were determined during exposure to pressure in solution held at 24 or 34C. For each species at both solution temperatures, water flux through root systems (Jv) grown at 34C was less than for roots grown at 24C. Roots of tree-of-heaven grown at 34C had lower hydraulic conductivity coefficients (Lp) than those grown at 24C, but Lp of roots of honey locust grown at the two temperatures was similar.

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Xuewen Gong, Shunsheng Wang, Cundong Xu, Hao Zhang, and Jiankun Ge

velocity, but it can become infinite when wind velocity is close to zero. Zhang and Lemeur (1992) reported that the aerodynamic resistance can be calculated by using the heat transfer coefficient inside greenhouse, but this coefficient needs canopy

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Rhuanito Soranz Ferrarezi, Thomas C. Geiger, Jayar Greenidge, Shamali Dennery, Stuart A. Weiss, and Gustavo H.S. Vieira

it matches the project design in the field. Pressure, water flow and distribution, and efficiency coefficients are necessary to evaluate system performance ( Silva and Silva, 2005 ). Drip irrigation has become one of the most common systems used for

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Giuseppe Vanella, Masoud Salyani, Paolo Balsari, Stephen H. Futch, and Roy D. Sweeb

evaluate the potential drift of nozzles in wind tunnels ( Derksen et al., 1999 ; Herbst 2001 ; Nuyttens et al., 2009 ). Wind tunnel may provide a method to classify drift potential of single or multiple nozzles without the effects of sprayer movement

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Toshio Shibuya, Akihito Sugimoto, Yoshiaki Kitaya, Makoto Kiyota, Yuichiro Nagasaka, and Shinya Kawaguchi

constructed with small plants such as transplants. In addition, this method is especially useful for evaluating plant responses to humidity, because the effects of humidity depend on the vapor pressure deficit (VPD) within the boundary layer of leaves ( Bunce

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Toshio Shibuya, Akihito Sugimoto, Yoshiaki Kitaya, and Makoto Kiyota

water stress resulting from high vapor-pressure deficit (VPD). Under higher plant density, the VPD near the leaf surface decreases as a result of the thicker boundary layer ( Kim et al., 1996b ; Kitaya et al., 1998 ), which inhibits water vapor exchange

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Brent Rowell and Mar Lar Soe

-watered grassy reference surface. Water levels in the pan are measured daily to determine the amount of water that has evaporated; this reference ET (ET o ) is expressed in millimeters or inches per day. ET is affected by solar radiation, air temperature, wind

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Giovanni Piccinni, Jonghan Ko, Thomas Marek, and Daniel I. Leskovar

Campbell Scientific, Inc. (Logan, UT) weather station every 6 s with 15-min outputs. These include solar radiation, wind speed, air temperature, dew point temperature, relative humidity, precipitation, and barometric pressure ( Dusek et al., 1987 ; Howell

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Bau-Show Lin and Yann-Jou Lin

(solar radiation, vapor pressure, wind velocity) to air temperature reduction (Δ T a ) and surface-soil temperature reduction (Δ T s ). Results Foliage densities (leaf area indexes), canopy thickness, canopy coverage areas, and leaf characteristics of the