14,443 research outputs found

    Three new synonymies in \u3ci\u3ePhyllophaga\u3c/i\u3e Harris, 1827 (Coleoptera: Scarabaeidae), with lectotype and neotype designations

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    In the course of working on new species of North American Phyllophaga Harris, 1827 (Coleoptera: Scarabaeidae: Melolonthinae) some synonyms have been found and are proposed here. New synonymies: Phyllophaga knausii (Schaeffer, 1907) is synonymized with Phyllophaga sociata (Horn, 1878); Phyllophaga chippewa Saylor, 1939 is synonymized with Phyllophaga rugosa (Melsheimer, 1845); and Phyllophaga falta Sanderson, 1950 is synonymized with Phyllophaga bipartita (Horn, 1887). Lectotypes are here designated for the following species: Listrochelus knausii Schaeffer, Listrochelus sociatus Horn, and Lachnosterna bipartita Horn. A neotype for Ancylonycha rugosa Melsheimer is here designated from the Horn Collection

    Facebook on College Campuses: Usage and Opinions of the Social Networking Site among College Students

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    Social Networking sites have emerged as college students’ number one source of communication. Facebook, ranked the number one SNS among college students, has gone from a student-only environment to the general public. In addition to exploring how college students are using the sire, I explore if students sex and year in school play a significant role in opinions about the site and how it is being used. Through a sample of 149 undergraduate college students, findings suggest that students seem to be using Facebook in the same ways and for the same reasons with little variation. Furthermore, my research proves that certain opinions of Facebook vary with students’ sex and year in school by older students have strong opinions of who is using the site and negative implications with females being more cautious of their privacy

    Reduced chemistry for butanol isomers at engine-relevant conditions

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    Butanol has received significant research attention as a second-generation biofuel in the past few years. In the present study, skeletal mechanisms for four butanol isomers were generated from two widely accepted, well-validated detailed chemical kinetic models for the butanol isomers. The detailed models were reduced using a two-stage approach consisting of the directed relation graph with error propagation and sensitivity analysis. During the reduction process, issues were encountered with pressure-dependent reactions formulated using the logarithmic pressure interpolation approach; these issues are discussed and recommendations made to avoid ambiguity in its future implementation in mechanism development. The performance of the skeletal mechanisms generated here was compared with that of detailed mechanisms in simulations of autoignition delay times, laminar flame speeds, and perfectly stirred reactor temperature response curves and extinction residence times, over a wide range of pressures, temperatures, and equivalence ratios. The detailed and skeletal mechanisms agreed well, demonstrating the adequacy of the resulting reduced chemistry for all the butanol isomers in predicting global combustion phenomena. In addition, the skeletal mechanisms closely predicted the time-histories of fuel mass fractions in homogeneous compression-ignition engine simulations. The performance of each butanol isomer was additionally compared with that of a gasoline surrogate with an antiknock index of 87 in a homogeneous compression-ignition engine simulation. The gasoline surrogate was consumed faster than any of the butanol isomers, with tert-butanol exhibiting the slowest fuel consumption rate. While n-butanol and isobutanol displayed the most similar consumption profiles relative to the gasoline surrogate, the two literature chemical kinetic models predicted different orderings.Comment: 39 pages, 16 figures. Supporting information available via https://doi.org/10.1021/acs.energyfuels.6b0185

    Genome Sequence of Kurthia Type Species Kurthia zopfii Strain ATCC 33403T

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    The genome of the type strain of the Kurthia genus, Kurthia zopfii ATCC 33403, was sequenced. Nonpathogenic K. zopfii has been isolated from intestinal contents, fecal material, meats, meat products, milk, water, and air, including air at high altitudes. The predicted genome size is 2,878,279 bp, with 37.05% G+C content

    Accelerating moderately stiff chemical kinetics in reactive-flow simulations using GPUs

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    The chemical kinetics ODEs arising from operator-split reactive-flow simulations were solved on GPUs using explicit integration algorithms. Nonstiff chemical kinetics of a hydrogen oxidation mechanism (9 species and 38 irreversible reactions) were computed using the explicit fifth-order Runge-Kutta-Cash-Karp method, and the GPU-accelerated version performed faster than single- and six-core CPU versions by factors of 126 and 25, respectively, for 524,288 ODEs. Moderately stiff kinetics, represented with mechanisms for hydrogen/carbon-monoxide (13 species and 54 irreversible reactions) and methane (53 species and 634 irreversible reactions) oxidation, were computed using the stabilized explicit second-order Runge-Kutta-Chebyshev (RKC) algorithm. The GPU-based RKC implementation demonstrated an increase in performance of nearly 59 and 10 times, for problem sizes consisting of 262,144 ODEs and larger, than the single- and six-core CPU-based RKC algorithms using the hydrogen/carbon-monoxide mechanism. With the methane mechanism, RKC-GPU performed more than 65 and 11 times faster, for problem sizes consisting of 131,072 ODEs and larger, than the single- and six-core RKC-CPU versions, and up to 57 times faster than the six-core CPU-based implicit VODE algorithm on 65,536 ODEs. In the presence of more severe stiffness, such as ethylene oxidation (111 species and 1566 irreversible reactions), RKC-GPU performed more than 17 times faster than RKC-CPU on six cores for 32,768 ODEs and larger, and at best 4.5 times faster than VODE on six CPU cores for 65,536 ODEs. With a larger time step size, RKC-GPU performed at best 2.5 times slower than six-core VODE for 8192 ODEs and larger. Therefore, the need for developing new strategies for integrating stiff chemistry on GPUs was discussed.Comment: 27 pages, LaTeX; corrected typos in Appendix equations A.10 and A.1
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