Thermally induced transverse cracking in T300/5208 graphite-epoxy cross-ply laminates was investigated experimentally and theoretically. The six laminate configura tions studied were: [0/903] s, [02/902]s, [03/90] s, [90/03]s, [902/02] s, and [903/0]s. The thermal load required to initiate transverse cracking was determined experimentally and compared to theoretical prediction. Experimental results for the accumulation of transverse cracks, under cyclic thermal loading between —250°F and 250°F for up to 500 thermal cycles, are presented. The calculated in situ transverse lamina strength was deter mined to be at least 1.9 times the unidirectional lamina transverse tensile strength. All laminate configurations exhibited an increase in crack density with increasing thermal cycles.
Science Needs of Southeastern Grassland Species of Conservation Concern: Species Status Assessment Framework extinctions, and human attitudes and behaviors; (4) invasive species (not limited to nonnative species); and (5) localized or subregional impacts such as sea-level rise. In addition to group discussions, workshop participants-as well as other grassland experts who were unable to attend the workshopcompleted a preworkshop survey concerning challenges and opportunities for grassland conservation. Findings reported here under each of these topics represent ideas, problems, hypotheses, and questions identified by a diverse community of grassland managers and researchers which may be addressed by future research and monitoring in southeastern grassland ecosystems to help guide science-based conservation of grassland-dependent species. Figure 1. Summed range-size rarity of imperiled species from the Map of Biodiversity Importance (NatureServe , 2021). This map was developed from habitat suitability models for 2,216 species ranked as critically imperiled (G1), imperiled (G2), or listed as endangered or threatened under the U.S. Endangered Species Act. Taxa include vertebrates, vascular plants, selected aquatic invertebrates (mussels and crayfish), and selected pollinators (bumblebees, butterflies, and skippers). High values identify areas with greater numbers of imperiled species with restricted ranges. Details on the habitat models used to produce this map are available from NatureServe (2021).
HerbivoryLarge herbivores are second only to fire as a dominant factor maintaining large areas of grassland worldwide. Grazing and browsing by a succession of large herbivores during and since the Pleistocene is the most plausible explanation for the persistence of high-elevation grassy balds in the southern Appalachians (Weigl and Knowles, 2014). Elsewhere,
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