734 research outputs found

    Preliminary design polymeric materials experiment

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    A typical Advanced Technology Laboratory mission flight plan was developed and used as a guideline for the identification of a number of experiment considerations. The experiment logistics beginning with sample preparation and ending with sample analysis are then overlaid on the mission in order to have a complete picture of the design requirements. The results of this preliminary design study fall into two categories. First specific preliminary designs of experiment hardware which is adaptable to a variety of mission requirements. Second, identification of those mission considerations which affect hardware design and will require further definition prior to final design. Finally, a program plan is presented which will provide the necessary experiment hardware in a realistic time period to match the planned shuttle flights. A bibliography of all material reviewed and consulted but not specifically referenced is provided

    Native American Educational Leader Preparation: The Design and Delivery of an Online Interdisciplinary Licensure Program

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    In a 1991 report, the Indian Nations at Risk Task Force documented a lack of Native educators as role models for Native American students and set a goal of doubling their number by the year 2000

    Formulation of a Technique for Evaluating Urban Highway Needs

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    Globular cluster population of the HST frontier fields galaxy J07173724+3744224

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    We present the first measurement of the globular cluster population surrounding the elliptical galaxy J07173724+3744224 (z=0.1546). This galaxy is located in the foreground in the field-of-view of the Hubble Space Telescope (HST) Frontier Fields observations of galaxy cluster MACS J0717.5+3745 (z=0.5458). Based on deep HST ACS F435W, F606W, and F814W images, we find a total globular cluster population of N_tot = 3441 +/- 1416. Applying the appropriate extinction correction and filter transformation from ACS F814W to the Johnson V-band, we determine that the host galaxy has an absolute magnitude of M_V = -22.2. The specific frequency was found to be S_N = 4.5 +/- 1.8. The radial profile of the globular cluster system was best fit using a powerlaw of the form σ∼R−0.6\sigma\sim R^{-0.6}, with the globular cluster population found to be more extended than the halo light of the host galaxy (σhalo∼R−1.7\sigma_{halo}\sim R^{-1.7}). The F435W-F814W colour distribution suggests a bimodal population, with red globular clusters 1-3x more abundant than blue clusters. These results are consistent with the host elliptical galaxy J07173724+3744224 having formed its red metal-rich GCs in situ, with the blue metal-poor globular clusters accreted from low-mass galaxies.Comment: 21 pages, 14 figures, 2 tables, revised following peer-review, accepted for publication in MNRA

    Contrasting Population Characteristics of Yellow Bass (Morone mississippiensis) in Two Southern Illinois Reservoirs

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    We investigated two southern Illinois reservoirs with contrasting size structures of yellow bass (Morone mississippiensis) to compare growth, mortality and recruitment patterns. Yellow bass were collected from Crab Orchard and Little Grassy Lakes during April-May 2009 using AC electrofishing. Total length and weight were recorded and sagittal otoliths sectioned and aged by two readers. Increments between otolith annuli were measured and the Weisberg linear growth model was used to assess age and environmental (growth year) effects on individual growth for fish from the two lakes. Von Bertalanffy growth models indicated faster growth and a greater maximum total length for yellow bass in Little Grassy Lake. However, growth of fish in Little Grassy Lake nearly ceased after age 4. The Weisberg model indicated differences in individual growth rate between the two lakes that were consistent across years (age effects were significant but growth year effects and the age-growth year interaction were not). Inter-lake differences in fish growth were present up to age 3. Recruitment was relatively stable in Crab Orchard, with year classes up to age 7 observed. Recruitment was more erratic in Little Grassy, with age 5 being the dominant year class and fish up to age 11 present. Differences in growth and recruitment patterns for yellow bass in these two lakes may be attributed to substantial inter-lake differences in turbidity, morphoedaphic index, or yellow bass density. Maximum age of yellow bass (age 11) was higher than previously reported for this species, likely due to the use of otoliths to age fish rather than scales. This study provides baseline information on age and growth, mortality, recruitment, and size structure of yellow bass that can be compared to data from future studies to elucidate factors influencing population dynamics of this species

    Detail-preserving fluid control

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    We propose a new fluid control technique that uses scale-dependent force control to preserve small-scale fluid detail. Control particles define local force fields and can be generated automatically from either a physical simulation or a sequence of target shapes. We use a multi-scale decomposition of the velocity field and apply control forces only to the coarse-scale components of the flow. Small-scale detail is thus preserved in a natural way avoiding the artificial viscosity often introduced by force-based control methods. We demonstrate the effectiveness of our method for both Lagrangian and Eulerian fluid simulation environments. © 2009 Elsevier Inc. All rights reserved
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