The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Brian Kane - One of the best experts on this subject based on the ideXlab platform.
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neighbour effects on tree architecture functional trade offs balancing crown competitiveness with Wind Resistance
Functional Ecology, 2017Co-Authors: David W. Macfarlane, Brian KaneAbstract:Summary The architecture of trees is the result of constrained, morphologically plastic growth – constrained by an underlying architectural model embedded in their genome, the structure of which can be significantly altered during growth to match the changing environmental conditions to which the tree is exposed. Here, we examined the hypothesis that crowding from neighbours should cause trees to optimize traits for light competition at the expense of Wind Resistance, with the reverse being true for trees lacking neighbours. Previous studies have examined the influence of light competition or Wind Resistance on shaping tree architecture, but few, if any, have simultaneously addressed trade-offs for optimizing these traits in response to crowding from neighbouring trees in forests, as compared to open-grown conditions. We studied the response of tree- and branch-level architectural traits of temperate, broad-leaved, deciduous tree species of differing shade tolerance and wood strength from multiple locations across the north-eastern United States. Trees ranged in size (4–83 cm diameter at 1·3 m) and crowding conditions (open- and forest-grown) and occupied different canopy positions. The open-grown trees represented a null condition, where the lack of neighbouring trees to shape architectural traits could be contrasted with the influence of different levels of crowding in forests. Our results show strong evidence for a tree neighbourhood-induced convergence of architectural traits across species and conditions, even when trees are growing in urban rather than natural forest conditions. After accounting for crowding, the effects of species and sample location contributed very little to explaining variation in architectural traits. One exception was crown dimensions, for which species-specific differences explained about 15% of the residual variation. Under open-grown conditions, alleviation of light competition caused trees to develop relatively large crowns and branches and a squat growth form suitable to resist greater Wind exposure. By contrast, increasing shading from neighbouring trees caused forest-grown trees to become increasingly more spindly in the main stem, with slender branches sparsely distributed over a disproportionately large crown volume – presumably to maximize light capture. Although the latter is an intrinsically less Wind-stable form, it can be adopted to increase light capture because neighbouring trees reduce exposure to the Wind, which should greatly reduce the likelihood of stem breakage or uprooting under critical Wind pressures. A lay summary is available for this article.
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Neighbour effects on tree architecture: functional trade‐offs balancing crown competitiveness with Wind Resistance
Functional Ecology, 2017Co-Authors: David W. Macfarlane, Brian KaneAbstract:Summary The architecture of trees is the result of constrained, morphologically plastic growth – constrained by an underlying architectural model embedded in their genome, the structure of which can be significantly altered during growth to match the changing environmental conditions to which the tree is exposed. Here, we examined the hypothesis that crowding from neighbours should cause trees to optimize traits for light competition at the expense of Wind Resistance, with the reverse being true for trees lacking neighbours. Previous studies have examined the influence of light competition or Wind Resistance on shaping tree architecture, but few, if any, have simultaneously addressed trade-offs for optimizing these traits in response to crowding from neighbouring trees in forests, as compared to open-grown conditions. We studied the response of tree- and branch-level architectural traits of temperate, broad-leaved, deciduous tree species of differing shade tolerance and wood strength from multiple locations across the north-eastern United States. Trees ranged in size (4–83 cm diameter at 1·3 m) and crowding conditions (open- and forest-grown) and occupied different canopy positions. The open-grown trees represented a null condition, where the lack of neighbouring trees to shape architectural traits could be contrasted with the influence of different levels of crowding in forests. Our results show strong evidence for a tree neighbourhood-induced convergence of architectural traits across species and conditions, even when trees are growing in urban rather than natural forest conditions. After accounting for crowding, the effects of species and sample location contributed very little to explaining variation in architectural traits. One exception was crown dimensions, for which species-specific differences explained about 15% of the residual variation. Under open-grown conditions, alleviation of light competition caused trees to develop relatively large crowns and branches and a squat growth form suitable to resist greater Wind exposure. By contrast, increasing shading from neighbouring trees caused forest-grown trees to become increasingly more spindly in the main stem, with slender branches sparsely distributed over a disproportionately large crown volume – presumably to maximize light capture. Although the latter is an intrinsically less Wind-stable form, it can be adopted to increase light capture because neighbouring trees reduce exposure to the Wind, which should greatly reduce the likelihood of stem breakage or uprooting under critical Wind pressures. A lay summary is available for this article.
Cccc Highway - One of the best experts on this subject based on the ideXlab platform.
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Sutong Bridge——a cable-stayed bridge with main span of 1 088 meters
Engineering Sciences, 2009Co-Authors: Cccc HighwayAbstract:In this paper,design and construction concepts are briefly presented.Furthermore,key technologies and innovative achievements are summarized mainly on piled foundation bearing capacity analysis,river bed scour protection and monitoring,superstructure Wind-Resistance study,mid-span closure method as well as long cantilever structure construction control.
David W. Macfarlane - One of the best experts on this subject based on the ideXlab platform.
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neighbour effects on tree architecture functional trade offs balancing crown competitiveness with Wind Resistance
Functional Ecology, 2017Co-Authors: David W. Macfarlane, Brian KaneAbstract:Summary The architecture of trees is the result of constrained, morphologically plastic growth – constrained by an underlying architectural model embedded in their genome, the structure of which can be significantly altered during growth to match the changing environmental conditions to which the tree is exposed. Here, we examined the hypothesis that crowding from neighbours should cause trees to optimize traits for light competition at the expense of Wind Resistance, with the reverse being true for trees lacking neighbours. Previous studies have examined the influence of light competition or Wind Resistance on shaping tree architecture, but few, if any, have simultaneously addressed trade-offs for optimizing these traits in response to crowding from neighbouring trees in forests, as compared to open-grown conditions. We studied the response of tree- and branch-level architectural traits of temperate, broad-leaved, deciduous tree species of differing shade tolerance and wood strength from multiple locations across the north-eastern United States. Trees ranged in size (4–83 cm diameter at 1·3 m) and crowding conditions (open- and forest-grown) and occupied different canopy positions. The open-grown trees represented a null condition, where the lack of neighbouring trees to shape architectural traits could be contrasted with the influence of different levels of crowding in forests. Our results show strong evidence for a tree neighbourhood-induced convergence of architectural traits across species and conditions, even when trees are growing in urban rather than natural forest conditions. After accounting for crowding, the effects of species and sample location contributed very little to explaining variation in architectural traits. One exception was crown dimensions, for which species-specific differences explained about 15% of the residual variation. Under open-grown conditions, alleviation of light competition caused trees to develop relatively large crowns and branches and a squat growth form suitable to resist greater Wind exposure. By contrast, increasing shading from neighbouring trees caused forest-grown trees to become increasingly more spindly in the main stem, with slender branches sparsely distributed over a disproportionately large crown volume – presumably to maximize light capture. Although the latter is an intrinsically less Wind-stable form, it can be adopted to increase light capture because neighbouring trees reduce exposure to the Wind, which should greatly reduce the likelihood of stem breakage or uprooting under critical Wind pressures. A lay summary is available for this article.
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Neighbour effects on tree architecture: functional trade‐offs balancing crown competitiveness with Wind Resistance
Functional Ecology, 2017Co-Authors: David W. Macfarlane, Brian KaneAbstract:Summary The architecture of trees is the result of constrained, morphologically plastic growth – constrained by an underlying architectural model embedded in their genome, the structure of which can be significantly altered during growth to match the changing environmental conditions to which the tree is exposed. Here, we examined the hypothesis that crowding from neighbours should cause trees to optimize traits for light competition at the expense of Wind Resistance, with the reverse being true for trees lacking neighbours. Previous studies have examined the influence of light competition or Wind Resistance on shaping tree architecture, but few, if any, have simultaneously addressed trade-offs for optimizing these traits in response to crowding from neighbouring trees in forests, as compared to open-grown conditions. We studied the response of tree- and branch-level architectural traits of temperate, broad-leaved, deciduous tree species of differing shade tolerance and wood strength from multiple locations across the north-eastern United States. Trees ranged in size (4–83 cm diameter at 1·3 m) and crowding conditions (open- and forest-grown) and occupied different canopy positions. The open-grown trees represented a null condition, where the lack of neighbouring trees to shape architectural traits could be contrasted with the influence of different levels of crowding in forests. Our results show strong evidence for a tree neighbourhood-induced convergence of architectural traits across species and conditions, even when trees are growing in urban rather than natural forest conditions. After accounting for crowding, the effects of species and sample location contributed very little to explaining variation in architectural traits. One exception was crown dimensions, for which species-specific differences explained about 15% of the residual variation. Under open-grown conditions, alleviation of light competition caused trees to develop relatively large crowns and branches and a squat growth form suitable to resist greater Wind exposure. By contrast, increasing shading from neighbouring trees caused forest-grown trees to become increasingly more spindly in the main stem, with slender branches sparsely distributed over a disproportionately large crown volume – presumably to maximize light capture. Although the latter is an intrinsically less Wind-stable form, it can be adopted to increase light capture because neighbouring trees reduce exposure to the Wind, which should greatly reduce the likelihood of stem breakage or uprooting under critical Wind pressures. A lay summary is available for this article.
Qiang Zhao - One of the best experts on this subject based on the ideXlab platform.
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Finite Element Analysis and Experimental Study on the Thermal Resistance Characteristics of Motor Coolers
Journal of Power of Technologies, 2020Co-Authors: Jie Yang, Chuansheng Tang, Qiang ZhaoAbstract:Motor coolers are operated with the coupling of temperature and pressure fields, in which the change rule is affected by multiple factors. In this study, the thermal Resistance of the motor cooler was examined using the velocity coefficient method to reveal the influence of heat transfer and Wind Resistance. The temperature and pressure fields were analyzed using the finite element method based on the hydrodynamics and momentum theorem. By varying the heat transfer and Wind Resistance coefficients to reflect temperature and pressure characteristics, Wind and water velocities were determined. Results demonstrate that the total convective heat transfer and Wind Resistance coefficients of the cooler model are sensitive to variations in face-to-face Wind velocity, but not to those of the cooling water flow rate. When Wind velocity increases from 0.8 to 5.19 m/s, the total convective heat transfer increases by 1.85 times and Wind Resistance increases by 18.74 times. Variations in cooling water velocity has little effect on the Nusselt number on the air side and the Euler number of the single row tube, which are multiplied with the increase of the Reynolds number. When the Reynolds number increases from 1020 to 6345, the Nusselt number increases by 2.05 times and the Euler number decreases by 2.29 times. The results provide references for the design and performance testing of high-power motor coolers.
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Study on Wind Resistance of Suspension Bridge with Composite Beam
Advanced Materials Research, 2012Co-Authors: Xiao Jun Ning, Qiang ZhaoAbstract:It is very important that how to improve Wind Resistance of bridge when design suspension bridge. In this thesis, main Wind disaster of suspension bridges is recommended, and summarizes the historical lessons. For the particularity of suspension bridge with composite beam, some suggestions on how to heighten flutter Wind speed are suggested.
Duoneng Liu - One of the best experts on this subject based on the ideXlab platform.
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Renewable power system simulation and endurance analysis for stratospheric airships
Renewable Energy, 2017Co-Authors: Xixiang Yang, Duoneng LiuAbstract:Abstract Composition of renewable power system for stratospheric airships is introduced, curved paving model of solar array is established, the high accuracy calculation method for output power of solar array is proposed, and operation process of renewable power system is simulated. On basis of this, endurance of the stratospheric airship is evaluated, and the influence of some important factors on endurance is analyzed, including Wind Resistance strategy, photoelectric transformation efficiency of solar array and the specific energy of lithium battery. Simulation results show that, 1) endurance of the stratospheric airship can be improved by adjusting power sequential during day and night with maneuverable Wind Resistance strategy, for the case in this paper, endurance increases 24.2 h compared with fixed point Wind Resistance strategy, 2) endurance can be greatly improved in a certain range through increasing photoelectric transformation efficiency of solar array and the specific energy of lithium battery, for cases in this paper, endurance increases 73.5 h and 47.5 h respectively, 3) to realize closed cycle of renewable power system during day and night, attenuation of radiation flux with the change of date must be considered in design of renewable power system, and sufficient redundancy should be designed for solar array.
