Aristelliger barbouri

Number of Pages: 1Integrative BiologyGeological Science

Thecadactylus, T. rapicauda

Number of Pages: 16Integrative BiologyGeological Science

Aristelliger

Number of Pages: 4Integrative BiologyGeological Science

Aristelliger georgeensis

Number of Pages: 2Integrative BiologyGeological Science

Anolis garmani

Number of Pages: 3Integrative BiologyGeological Science

Design, Development, and Testing of a Low Cost, Additively-Manufactured, Centrifugal Compressor

The three objectives of this research were to: 1.) design, build, and test AM compressors to substitute into COTS micro-gas turbine engines, 2.) provide initial correlations between FEA and compressor failure speed, and 3.) characterize the effects of AM on compressor performance. These goals improved the design cycle cost and the design-validation time cycle. ULTEM 9085, 300-AMB, and Onyx-Kevlar temperature-dependent tensile properties were measured. FEA-predicted failure speeds of stock compressor designs led design improvements, potentially fulfilling the original compressor requirements. Physical testing of the stock and ULTEM 9085 compressors occurred. Comparing these compressors\u27 performances demonstrated that low cost, AM materials are viable alternatives for certain micro-turbine applications. An improved Onyx-Carbon Fiber compressor was tested to failure. These results provide a proof of concept supporting AM compressors, improving the development time cycle. This approach enables high-risk yet low-cost research and development. Additionally, with proper mission planning, low-cost AM compressors could provide significant improvements to engine cost and weight for limited-life applications

Aristelliger praesignis

Number of Pages: 4Integrative BiologyGeological Science

Aristelliger lar

Number of Pages: 3Integrative BiologyGeological Science

Anolis grahami

Number of Pages: 4Integrative BiologyGeological Science

The measure of success: geographic isolation promotes diversification in Pachydactylus geckos

Abstract Background Geckos of the genus Pachydactylus and their close relatives comprise the most species-rich clade of lizards in sub-Saharan Africa. Many explanations have been offered to explain species richness patterns of clades. In the Pachydactylus group, one possible explanation is a history of diversification via geographic isolation. If geographic isolation has played a key role in facilitating diversification, then we expect species in more species-rich subclades to have smaller ranges than species in less diverse subclades. We also expect traits promoting geographic isolation to be correlated with small geographic ranges. In order to test these expectations, we performed phylogenetic analyses and tested for correlations among body size, habitat choice, range sizes, and diversification rates in the Pachydactylus group. Results Both body size and habitat use are inferred to have shifted multiple times across the phylogeny of the Pachydactylus group, with large size and generalist habitat use being ancestral for the group. Geographic range size is correlated with both of these traits. Small-bodied species have more restricted ranges than large-bodied species, and rock-dwelling species have more restricted ranges than either terrestrial or generalist species. Rock-dwelling and small body size are also associated with higher rates of diversification, and subclades retaining ancestral conditions for these traits are less species rich than subclades in which shifts to small body size and rocky habitat use have occurred. The phylogeny also illustrates inadequacies of the current taxonomy of the group. Conclusions The results are consistent with a model in which lineages more likely to become geographically isolated diversify to a greater extent, although some patterns also resemble those expected of an adaptive radiation in which ecological divergence acts as a driver of speciation. Therefore, the Pachydactylus group may represent an intermediate between clades in which radiation is adaptive versus those in which it is non-adaptive.http://deepblue.lib.umich.edu/bitstream/2027.42/135714/1/12862_2016_Article_846.pd