2 resultados para Stand-Alone Inverters

em University of Connecticut - USA


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We investigated tree sway and crown collision behavior of even-aged lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands of different structure in Alberta, Canada, to examine how these factors might affect loss of leaf area as stands mature. The Two Creeks stand (TC) had high density and slender trees, while the Chickadee stand (CH) had stout trees. The TC stand was then thinned (TCT) to reduce the stand density. For each stand, simultaneous tree sways of a group of 10 trees were monitored with biaxial clinometers during wind speed of 5 m/s (canopy top). Crown collisions were reconstructed by combining sway displacement of individual trees with their respective crown dimensions. Comparing the sway statistics between stands with contrasting mean bole slenderness (TC and CH) indicated that more slender trees have greater sway displacements, faster sway speeds, and a greater depth of collision. Disturbance by thinning increased sway displacements, sway speeds, and depth of collisions at TCT. Tree sway patterns were circular in shape and not aligned with wind direction, but patterns were elongated after thinning. This demonstrates the high frequency of crown collision experienced by stands with slender trees and supports the notion that crown collisions result in empty space between crowns of trees.

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In June 1891, Shimshon Gerye, a Jewish immigrant from Galicia (a region that now falls across the border of Ukraine and Poland) living in Sedalia, Missouri, received a letter from a cousin back home. The content of the letter was probably rather mundane (a request to send money, inquiries about health), but its timing was somewhat unusual: in the thirty-five years that Shimshon had been living in America, this was apparently the first he had heard from his family in Europe. What survives of the ensuing correspondence, written in Yiddish and spanning a one-year period, provides an interesting view of the situation of the immigrant and the pressures of assimilation, as well as the Yiddish language in America at the end of the nineteenth century.