764 research outputs found

    Numerical marching techniques for fluid flows with heat transfer

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    The finite difference formulation and method of solution is presented for a wide variety of fluid flow problems with associated heat transfer. Only a few direct results from these formulations are given as examples, since the book is intended primarily to serve a discussion of the techniques and as a starting point for further investigations; however, the formulations are sufficiently complete that a workable computer program may be written from them. In the appendixes a number of topics are discussed which are of interest with respect to the finite difference equations presented. These include a very rapid method for solving certain sets of linear algebraic equations, a discussion of numerical stability, the inherent error in flow rate for confined flow problems, and a method for obtaining high accuracy with a relatively small number of mesh points

    Viscous flow in a short cylindrical vortex chamber with a finite swirl ratio

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    Laminar incompressible viscous flow in short cylindrical vortex chamber with finite swirl rati

    A Comparison of the Ichthyofaunal Trophic Ecology at Selected Limestone Artificial Reef Sites and Adjacent Natural Reef Sites

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    Artificial reefs may enhance the biological production of reef-associated flora and fauna, but their trophic structure relative to that of natural reefs remains understudied. We assessed trophic dynamics by comparing δ13C and δ15N in 43 fish species from artificial and natural reef tracts of Broward County, Florida. We tested the effect of sampling location (artificial, first, and second reef), general feeding strategy (herbivore, omnivore, planktivore, invertivore, and carnivore), phylogeny, and standard length. For all samples, δ13C and δ15N ranged from -19.5 to -13.1‰ and 6.7 to 13.3‰, respectively. Lower trophic level feeding behavior resulted in more depleted δ13C and δ15N and higher trophic level feeding behavior resulted in more enriched δ13C and δ15N. We detected significant effects of both general feeding strategy and phylogeny. We also detected significant differences in δ13C and δ15N profiles between artificial and natural reefs; however, these differences were not great enough to suggest changes in the feeding strategy or trophic dynamics of individual fish taxa

    Washington\u27s Closed-Circuit Testimony Statute: An Exception to the Confrontation Clause to Protect Victims in Child Abuse Prosecutions

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    This Comment argues that E.S.H.B. 2809 should be recognized as an exception to the Confrontation Clause by the Supreme Courts of the United States and Washington. This argument rests upon the premise that E.S.H.B. 2809 falls within the boundaries set by previously recognized exceptions to the hearsay rule and by federal and Washington case law. Indeed, the reliability and trustworthiness of the victim\u27s testimony should not turn on the child\u27s ability to withstand the additional psychological trauma often induced by in-court testimony.\u27 Rather, the special problems that these children bring to the courtroom demand compliance with a statute such as the Washington closed-circuit testimony statute to increase the requirements of reliability and trustworthiness. Thus, the statute satisfies the strict constitutional requirements of the Confrontation Clause

    Washington\u27s Closed-Circuit Testimony Statute: An Exception to the Confrontation Clause to Protect Victims in Child Abuse Prosecutions

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    This Comment argues that E.S.H.B. 2809 should be recognized as an exception to the Confrontation Clause by the Supreme Courts of the United States and Washington. This argument rests upon the premise that E.S.H.B. 2809 falls within the boundaries set by previously recognized exceptions to the hearsay rule and by federal and Washington case law. Indeed, the reliability and trustworthiness of the victim\u27s testimony should not turn on the child\u27s ability to withstand the additional psychological trauma often induced by in-court testimony.\u27 Rather, the special problems that these children bring to the courtroom demand compliance with a statute such as the Washington closed-circuit testimony statute to increase the requirements of reliability and trustworthiness. Thus, the statute satisfies the strict constitutional requirements of the Confrontation Clause

    Arkansas Cotton Variety Test 1999

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    The primary aim of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties in the major cotton growing areas in Arkansas. This information helps seed dealers establish marketing strategies and assists producers in choosing varieties to plant. In this way the annual test facilitates the inclusion of new, improved genetic material into Arkansas cotton production. The 1999 test had 67 entries (including 25 transgenic genotypes and 35 first-year entries), which were evaluated at sixsites in eastern Arkansas. The presence of four transgenic and five first-year entries among the top 10 yielding entries suggests that improvement is being accomplished in varietal development. This report also includes the Mississippi County Variety Test (an on-farm evaluation of selected varieties) and on-farm variety trials conducted by the Cooperative Extension Service

    Arkansas Cotton Variety Test 2004

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    The primary aim of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed dealers establish marketing strategies and assists producers in choosing varieties to plant

    Large-area CCD imagers for spacecraft applications

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    Backside illuminated CCD imagers with 100 x 160 resolution elements have been fabricated using double level metal technology. Detailed study of the optical performance of such arrays has been performed between 24 C and -40 C using data rates from 10 kHz to 1 MHz. A 400 x 400 array is presently being fabricated

    Collision of Domain Walls and Reheating of the Brane Universe

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    We study a particle production at the collision of two domain walls in 5-dimensional Minkowski spacetime. This may provide the reheating mechanism of an ekpyrotic (or cyclic) brane universe, in which two BPS branes collide and evolve into a hot big bang universe. We evaluate a production rate of particles confined to the domain wall. The energy density of created particles is given as ρ20gˉ4Nb mη4\rho \approx 20 \bar{g}^4 N_b ~m_\eta^4 where gˉ\bar{g} is a coupling constant of particles to a domain-wall scalar field, NbN_b is the number of bounces at the collision and mηm_\eta is a fundamental mass scale of the domain wall. It does not depend on the width dd of the domain wall, although the typical energy scale of created particles is given by ω1/d\omega\sim 1/d. The reheating temperature is evaluated as TR0.88 gˉ Nb1/4T_{\rm R}\approx 0.88 ~ \bar{g} ~ N_b^{1/4}. In order to have the baryogenesis at the electro-weak energy scale, the fundamental mass scale is constrained as m_\eta \gsim 1.1\times 10^7 GeV for gˉ105\bar{g}\sim 10^{-5}.Comment: 10 pages, 12 figure

    Panchromatic Imaging of a Transitional Disk: The Disk of GM Aur in Optical and FUV Scattered Light

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    We have imaged GM Aur with HST, detected its disk in scattered light at 1400A and 1650A, and compared these with observations at 3300A, 5550A, 1.1 microns, and 1.6 microns. The scattered light increases at shorter wavelengths. The radial surface brightness profile at 3300A shows no evidence of the 24AU radius cavity that has been previously observed in sub-mm observations. Comparison with dust grain opacity models indicates the surface of the entire disk is populated with sub-micron grains. We have compiled an SED from 0.1 microns to 1 mm, and used it to constrain a model of the star+disk system that includes the sub-mm cavity using the Monte Carlo Radiative Transfer code by Barbara Whitney. The best-fit model image indicates that the cavity should be detectable in the F330W bandpass if the cavity has been cleared of both large and small dust grains, but we do not detect it. The lack of an observed cavity can be explained by the presence of sub-microns grains interior to the sub-mm cavity wall. We suggest one explanation for this which could be due to a planet of mass <9 Jupiter masses interior to 24 AU. A unique cylindrical structure is detected in the FUV data from the Advanced Camera for Surveys/Solar Blind Channel. It is aligned along the system semi-minor axis, but does not resemble an accretion-driven jet. The structure is limb-brightened and extends 190 +/- 35 AU above the disk midplane. The inner radius of the limb-brightening is 40 +/- 10 AU, just beyond the sub-millimeter cavity wall.Comment: 40 pages, 11 figures, 4 tables, accepted to Ap
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