3,080 research outputs found

    Hypervelocity Impact of Composite Overwrap Pressure Vessels

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    There is a limited amount of hypervelocity impact (HVI) data on pressurized composite overwrapped pressure vessels (COPV). In recent years, NASA has performed HVI tests to characterize impact conditions resulting in either leak or burst of the COPVs representative of spacecraft hardware. This paper reports on the results of 40 tests that have been conducted on several types of COPV configurations, pressurized by inert gas to near the vessels rated maximum expected operating pressure (MEOP). These tests were used to better understand COPV response under HVI conditions and develop ballistic limit equations (BLE) related to these tests

    Magic Numbers for the Photoelectron Anisotropy in Li-Doped Dimethyl Ether Clusters

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    Photoelectron velocity map imaging of Li(CH3_3OCH3_3)n_n clusters (1 \leq n \leq 175) is used to search for magic numbers related to the photoelectron anisotropy. Comparison with density functional calculations reveals magic numbers at n=4, 5, and 6, resulting from the symmetric charge distribution with high s-character of the highest occupied molecular orbital. Since each of these three cluster sizes correspond to the completion of a first coordination shell, they can be considered as 'isomeric motifs of the first coordination shell'. Differences in the photoelectron anisotropy, the vertical ionization energies and the enthalpies of vaporization between Li(CH3_3OCH3_3)n_n and Na(CH3_3OCH3_3)n_n can be rationalized in terms of differences in their solvation shells, atomic ionization energies, polarizabilities, metal-oxygen bonds, ligand-ligand interactions, and by cooperative effects

    Ocean Chlorophyll Studies from a U-2 Aircraft Platform

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    Chlorophyll gradient maps of large ocean areas were generated from U-2 ocean color scanner data obtained over test sites in the Pacific and Atlantic Oceans. The delineation of oceanic features using the upward radiant intensity relies on an analysis method which presupposes that radiation backscattered from the atmosphere and ocean surface can be properly modeled using a measurement made at 778 nm. An estimation of the chlorophyll concentration was performed by properly ratioing radiances measured at 472 nm and 548 nm after removing the atmospheric effects. The correlation between the remotely sensed data and in-situ surface chlorophyll measurements was validated in two sets of data. The results show that the correlation between the in-situ measured chlorophyll and the derived quantity is a negative exponential function and the correlation coefficient was calculated to be -0.965

    Developmental and tissue-specific expression of NITRs

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    Novel immune-type receptors (NITRs) are encoded by large multi-gene families and share structural and signaling similarities to mammalian natural killer receptors (NKRs). NITRs have been identified in multiple bony fish species, including zebrafish, and may be restricted to this large taxonomic group. Thirty-nine NITR genes that can be classified into 14 families are encoded on zebrafish chromosomes 7 and 14. Herein, we demonstrate the expression of multiple NITR genes in the zebrafish ovary and during embryogenesis. All 14 families of zebrafish NITRs are expressed in hematopoietic kidney, spleen and intestine as are immunoglobulin and T cell antigen receptors. Furthermore, all 14 families of NITRs are shown to be expressed in the lymphocyte lineage, but not in the myeloid lineage, consistent with the hypothesis that NITRs function as NKRs. Sequence analyses of NITR amplicons identify known alleles and reveal additional alleles within the nitr1, nitr2, nitr3, and nitr5 families, reflecting the recent evolution of this gene family

    Adoption Process for the Model Aquatic Health Code: An Example

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    In 2014 the U.S. Centers for Disease Control and Prevention (CDC) published the first edition of the Model Aquatic Health Code (MAHC). This document represented the inaugural introduction of a federal policy guideline with a direct focus in the area of aquatic venue operation and maintenance with the sole purpose of improving the nature of public health in the field. The Indiana State Department of Health (ISDH) began the review and adoption process soon after the policy’s release. The ISDH process is proposed as one method for others to consider. The background and history of the MAHC are presented in this manuscript along with an overview of the adoption process to date that has been employed by the State of Indiana. In addition, information is provided on the Diffusion of Innovations Theory (DIT) as a possible method for assessing the long-term adoption of the MAHC on a national level

    Cape Romain and the Charleston Bump: Historical and Recent Hydrographic Observations

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    A review and analysis of historical and new hydrographic data are presented for the Charleston Bump region. An area of doming isotherms is identified primarily between 31.5° and 34.5°N and the 200 and 400 m isobaths. The highest incidences of doming are found off Long Bay (86%), Cape Fear (38%), and Cape Romain (25%). Evidence suggests that low salinity shelf water collects in the doming area off Long Bay in July and that seasonal fluctuations in the depth of the main thermocline layer in this area are linked to Gulf Stream transport and local winds. At times there is a gradual offshore‐onshore movement of the Gulf Stream opposite Long Bay roughly following the 400 m isobath and at other times an abrupt eastward movement near 32°N. Much of the time there appears to be a direct seasonal relationship between historical seasonal velocity fields and offshore deflection with higher (lower) velocities corresponding to greater (lesser) deflection

    The use of DiazaConTM to limit fertility in grey squirrels

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    Mayle, B., Ferryman, M., Peace, A., Yoder, C.A., Miller, L.A., Cowan, D

    POTENTIAL BIRD REPELLENTS TO REDUCE BIRD DAMAGE TO LETTUCE SEED AND SEEDLINGS

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    The authors evaluated the effectiveness of ReJeX-iT® AG-145, Mesurol®, activated charcoal, lime, and fipronil to reduce homed lark damage to lettuce seeds and seedlings. In Experiment 1, homed larks consumed significantly more feed mixture (50:50 grains and lettuce seed) than untreated clay-coated lettuce seed in a three-day choice-test. In Experiment 2, where clay-coated lettuce seed was treated with ReJeX-iT® AG- 145, Mesurol®, activated charcoal, or lime, there was no significant difference in consumption of untreated clay-coated lettuce seed and treated clay-coated lettuce seed. Homed larks consumed insignificant amounts of all seed treatments including untreated coated lettuce seed. In this experiment homed larks lost an average of 28 % of their body weight over the three-day test period. It was concluded that the clay seed coating alone reduced damage significantly. In the aviary test, flats of sprouting lettuce seedlings were sprayed with Mesurol® (4 kg/ha), ReJeX-iT® AG-145 (64 kg/ha), lime (32 kg/ha), activated charcoal (32 kg/ha), and fipronil(4 kg/ha). Mesurol®, ReJeX-iT® AG-145, and lime significantly reduced consumption of lettuce seedlings over a four-day test period. Even though lime significantly reduced consumption, homed larks still consumed over 50% of the available lettuce seedlings. Field evaluations are warranted with Mesurol® and ReJeX-iT® AG-145
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