3,044 research outputs found

    Chicago Board of Trade Ethanol Contract Efficiency

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    Firms producing ethanol may find management of the price risk associated with production of this leading alternative fuel a key factor to continued success. As with other agricultural commodities, the influence and ability of futures contracts to serve as a risk management tool deserves attention.contract efficiency, ethanol, futures contracts, Crop Production/Industries, Risk and Uncertainty, Q13, Q43, M31,

    Assessment of the Compositional Influences on the Toughness of TiCr\u3csub\u3e2\u3c/sub\u3e-Base Laves Phase Alloys

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    Systematic studies of alloys based on TiCr, have been performed in order to improve the toughness of Laves phase intermetallics. The extent to which alloy compositions and annealing treatments influence the toughness was quantified by Vickers indentation. The single-phase Laves behavior was first established by studying stoichiometric and nonstoichiometric TiCr,. Next, alloying effects were investigated with ternary Laves phases based on TiCr2. Different microstructures of two-phase alloys consisting of (Ti,Cr)-bcc+TiCr2, were also examined. Various toughening theories based on vacancies, site-substitutions, crystal structure (C14, C36, or Cl5) stabilization, and the presence of a second phase were evaluated. The most effective factors improving the toughness of TiCr2, were determined, and toughening mechanisms are suggested

    Incorporating collisions and resistance into the transition from field emission to the space charge regime

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    Advancements in microelectromechanical systems (MEMS) and microplasmas, particularly with respect to applications in combustion and biotechnology, motivate studies into microscale gas breakdown to enable safe system design and implementation. Breakdown at microscale deviates from that predicted by Paschen’s law due to field emission—the stripping of electrons from the cathode in the presence of strong surface field—and follows the Fowler-Nordheim (FN) law. As injected current increases at this length scale, electrons accumulate in the gap and FN electron emission becomes space charge limited, leading to the Child-Langmuir (CL) law at vacuum and the Mott-Gurney (MG) law at high pressure. While theoretical studies link CL to FN and CL to MG, none links all three to simultaneously assess the importance of pressure and external resistance (perturbation) on electron emission. This study extends existing theory to elucidate the transition between these regimes as a function of applied voltage, gap distance, electron mobility, and external resistance, and in particular, derives asymptotic equations illustrating the transitions between the three. It also demonstrates the presence of a triple point, where one theoretically encounters FN, CL, and MG at once, and characterizes the importance of gap pressure and distance on these regimes, especially when MG dominates at non-vacuum pressures. The sensitivity of the triple point to external resistance, representative of the effects of perturbations in system parameters on electron emission, receives special attention

    Reconstructing the colonization history of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Northwestern Australia

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    Bottlenose dolphins (Tursiops spp.) are found in waters around Australia, with T. truncatus typically occupying deeper, more oceanic habitat, while T. aduncus occur in shallower, coastal waters. Little is known about the colonization history of T. aduncus along the Western Australian coastline; however, it has been hypothesized that extant populations are the result of an expansion along the coastline originating from a source in the north of Australia. To investigate the history of coastal T. aduncus populations in the area, we generated a genomic SNP dataset using a double-digest restriction-site-associated DNA (ddRAD) sequencing approach. The resulting dataset consisted of 103,201 biallelic SNPs for 112 individuals which were sampled from eleven coastal and two offshore sites between Shark Bay and Cygnet Bay, Western Australia. Our population genomic analyses showed a pattern consistent with the proposed source in the north with significant isolation by distance along the coastline, as well as a reduction in genomic diversity measures along the coastline with Shark Bay showing the most pronounced reduction. Our demographic analysis indicated that the expansion of T. aduncus along the coastline began around the last glacial maximum and progressed southwards with the Shark Bay population being founded only 13 kya. Our results are in line with coastal colonization histories inferred for Tursiops globally, highlighting the ability of delphinids to rapidly colonize novel coastal niches as habitat is released during glacial cycle-related global sea level and temperature changes

    Automated Absorber Attachment for X-ray Microcalorimeter Arrays

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    Our goal is to develop a method for the automated attachment of large numbers of absorber tiles to large format detector arrays. This development includes the fabrication of high quality, closely spaced HgTe absorber tiles that are properly positioned for pick-and-place by our FC150 flip chip bonder. The FC150 also transfers the appropriate minute amount of epoxy to the detectors for permanent attachment of the absorbers. The success of this development will replace an arduous, risky and highly manual task with a reliable, high-precision automated process

    Detection and quantification of angiogenesis in experimental valve disease with integrin-targeted nanoparticles and 19-fluorine MRI/MRS

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    <p>Abstract</p> <p>Background</p> <p>Angiogenesis is a critical early feature of atherosclerotic plaque development and may also feature prominently in the pathogenesis of aortic valve stenosis. It has been shown that MRI can detect and quantify specific molecules of interest expressed in cardiovascular disease and cancer by measuring the unique fluorine signature of appropriately targeted perfluorocarbon (PFC) nanoparticles. In this study, we demonstrated specific binding of α<sub>ν</sub>β<sub>3 </sub>integrin targeted nanoparticles to neovasculature in a rabbit model of aortic valve disease. We also showed that fluorine MRI could be used to detect and quantify the development of neovasculature in the excised aortic valve leaflets.</p> <p>Methods</p> <p>New Zealand White rabbits consumed a cholesterol diet for ~180 days and developed aortic valve thickening, inflammation, and angiogenesis mimicking early human aortic valve disease. Rabbits (n = 7) were treated with α<sub>ν</sub>β<sub>3 </sub>integrin targeted PFC nanoparticles or control untargeted PFC nanoparticles (n = 6). Competitive inhibition <it>in vivo </it>of nanoparticle binding (n = 4) was tested by pretreatment with targeted nonfluorinated nanoparticles followed 2 hours later by targeted PFC nanoparticles. 2 hours after treatment, aortic valves were excised and <sup>19</sup>F MRS was performed at 11.7T. Integrated <sup>19</sup>F spectral peaks were compared using a one-way ANOVA and Hsu's MCB (multiple comparisons with the best) post hoc t test. In 3 additional rabbits treated with α<sub>ν</sub>β<sub>3 </sub>integrin targeted PFC nanoparticles, <sup>19</sup>F spectroscopy was performed on a 3.0T clinical scanner. The presence of angiogenesis was confirmed by immunohistochemistry.</p> <p>Results</p> <p>Valves of rabbits treated with targeted PFC nanoparticles had 220% more fluorine signal than valves of rabbits treated with untargeted PFC nanoparticles (p < 0.001). Pretreatment of rabbits with targeted oil-based nonsignaling nanoparticles reduced the fluorine signal by 42% due to competitive inhibition, to a level not significantly different from control animals. Nanoparticles were successfully detected in all samples scanned at 3.0T. PECAM endothelial staining and α<sub>ν</sub>β<sub>3 </sub>integrin staining revealed the presence of neovasculature within the valve leaflets.</p> <p>Conclusion</p> <p>Integrin-targeted PFC nanoparticles specifically detect early angiogenesis in sclerotic aortic valves of cholesterol fed rabbits. These techniques may be useful for assessing atherosclerotic components of preclinical aortic valve disease in patients and could assist in defining efficacy of medical therapies.</p

    The Lantern Vol. 26, No. 3, June 1958

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    • Reflections • Recession: A Matter of Opinion • His Name Was... • The Outward Bound • A Champion There Was • Notes from the Sukura • Undauntedhttps://digitalcommons.ursinus.edu/lantern/1075/thumbnail.jp
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