3,607 research outputs found

    LMSS propagation modeling at Virginia Tech

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    Recent efforts in the modeling of land mobile satellite systems are reported. These include descriptions of a simple model for prediction of fading statistics, a propagation simulator, and results from studies using the simulator. Predictions are compared to available measured data

    A Mixed Methods Approach to Identifying Administration Issues Pertinent in Interscholastic Sports

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    The purpose of this study was to investigate three propositions: a) What are the administration issues most pertinent to interscholastic sport today, as well as the next five years?, b) How important are those administration issues to athletic administrators?, and c) What are the potential implications of those pertinent administration issues to practicing athletic administrators? The literature provides a general overview of relevant issues surrounding interscholastic athletics. However, the importance and implications of relevant issues to practicing high school athletic administrators are difficult to discern. To answer the first proposition, the Minnesota State High School League (MSHSL) provided 10 contemporary administration issues that were most pertinent to interscholastic sport today, as well as the next five years. To answer the second proposition, a Likert-Scale was created so that practicing athletic administrators could rate each issue on a scale of 5 = extremely important to 1 = very little importance. A national study was conducted with athletic directors from the National Interscholastic Athletic Administrators Association (N = 170) annual conference. A one-tailed ANOVA was executed to determine significant differences among the 10 administration issues identified by the MSHSL. Four issues were found to be significant; Athletic Facilities, Athletic Training, Health Issues and Travel Teams. A Games-Howell post hoc was executed to determine significant differences across geographical regions of the United States. For the third proposition, semi-structured interviews were completed to provide insight on the implications for practicing athletic administrators. The results offer insight from which further investigations could be conducted to continue building on policies that influence interscholastic athletic administrators’ day-to-day accountability when overseeing their athletic programs

    Intergalactic Baryons in the Local Universe

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    Simulations predict that shocks from large-scale structure formation and galactic winds have reduced the fraction of baryons in the warm, photoionized phase (the Lya forest) from nearly 100% in the early universe to less than 50% today. Some of the remaining baryons are predicted to lie in the warm-hot ionized medium (WHIM) phase at T=10^5-10^7 K, but the quantity remains a highly tunable parameter of the models. Modern UV spectrographs have provided unprecedented access to both the Lya forest and potential WHIM tracers at z~0, and several independent groups have constructed large catalogs of far-UV IGM absorbers along ~30 AGN sight lines. There is general agreement between the surveys that the warm, photoionized phase makes up ~30% of the baryon budget at z~0. Another ~10% can be accounted for in collapsed structures (stars, galaxies, etc.). However, interpretation of the ~100 high-ion (OVI, etc) absorbers at z<0.5 is more controversial. These species are readily created in the shocks expected to exist in the IGM, but they can also be created by photoionization and thus not represent WHIM material. Given several pieces of observational evidence and theoretical expectations, I argue that most of the observed OVI absorbers represent shocked gas at T~300,000 K rather than photoionized gas at T<30,000 K, and they are consequently valid tracers of the WHIM phase. Under this assumption, enriched gas at T=10^5-10^6 K can account for ~10% of the baryon budget at z<0.5, but this value may increase when bias and incompleteness are taken into account and help close the gap on the 50% of the baryons still "missing".Comment: Invited review to appear in "Future Directions in Ultraviolet Spectroscopy", Oct 20-22, 2008, Annapolis, MD, M. E. Van Steenberg, ed. (April 2009). 8 pages, five figure

    pH-Independent, 520 mV Open-Circuit Voltages of Si/Methyl Viologen^(2+/+) Contacts Through Use of Radial n^+p-Si Junction Microwire Array Photoelectrodes

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    The effects of introducing an n^+-doped emitter layer have been evaluated for both planar Si photoelectrodes and for radial junction Si microwire-array photoelectrodes. In contact with the pH-independent, one-electron, outer-sphere, methyl viologen redox system (denoted MV^(2+/+)), both planar and wire array p-Si photoelectrodes yielded open-circuit voltages, V_(oc), that varied with the pH of the solution. The highest V_(oc) values were obtained at pH = 2.9, with V_(oc) = 0.53 V for planar p-Si electrodes and V_(oc) = 0.42 V for vapor−liquid−solid catalyzed p-Si microwire array samples, under 60 mW cm^(−2) of 808 nm illumination. Increases in the pH of the electrolyte produced a decrease in V_(oc) by approximately −44 mV/pH unit for planar electrodes, with similar trends observed for the Si microwire array electrodes. In contrast, introduction of a highly doped, n^+ emitter layer produced V_(oc) = 0.56 V for planar Si electrodes and V_(oc) = 0.52 V for Si microwire array electrodes, with the photoelectrode properties in each system being essentially independent of pH over six pH units (3 < pH < 9). Hence, formation of an n^+ emitter layer not only produced nearly identical photovoltages for planar and Si microwire array photoelectrodes, but decoupled the band energetics of the semiconductor (and hence the obtainable photovoltage) from the value of the redox potential of the solution. The formation of radial junctions on Si microwire arrays thus provides an approach to obtaining Si-based photoelectrodes with high-photovoltages that can be used for a variety of photoelectrochemical processes, including potentially the hydrogen evolution reaction, under various pH conditions, regardless of the intrinsic barrier height and flat-band properties of the Si/liquid contact

    A CPTED bibliography: Publications related to urban space, planning, architecture, and crime prevention through environmental design, 1975-2010

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    This compendium is the result of two different bibliographies. The first was completed by Sean Michael, Professor and Department Head of the Department of Landscape Architecture and Environmental Planing at Utah State University. The second was completed by Gregory Saville, urban planner and Principal of AlterNation Consulting, started during graduate work at the Faculty of Environmental Studies at York University. Consolidation and expansion of the two works was overseen by Joel Warren, during his Masters of Landscape Architecture at Utah State University. Our thanks go to the many students, colleagues, and friends who contributed to this work over the years. They include: Anna Brassard, Paul Cozens, Misty Fitch, Chuck Genre, and Diane Zahm. Earlier versions have appeared in different venues through the years such as the 2003 ICA CPTED Bibliography available on CD through the International CPTED Association and the Latin America CPTED Region Corporation. In addition, Emerald Press has published a detailed literature review of basic 1st Generation CPTED studies (P. Cozens, G. Saville and D. Hillier, “Crime prevention through environmental design: A review and modern bibliography”, Property Management. 23(5), 2005). Finally, an early version was available via The CPTED Page (www.thecptedpage.wsu.edu). Today, the resource is jointly hosted through the web site of Safe Cascadia (www.safecascadia.org

    Solar Water Splitting Cells

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    Improved selection of technically attractive projects using knowledge management and net interactive tools

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    Thesis (S.M.)--Massachusetts Institute of Technology, System Design & Management Program, February 2000."January 2000."Includes bibliographical references (p. 73-77).Conventional technology forecasting and selection practices, in the Western World, suffer from several shortcomings including: weak criteria for developing and evaluating forecasts, limited tool sets for developing possible future states of implementation, anchoring in current functional capability and strong dependence on functional experts. Techniques enabled by the existence of the World Wide Web bring additional knowledge assets to assist in developing suitable forecasts and related technology selection. Additionally, techniques developed by Altshuller provide a powerful set of visioning tools, titled the Laws and Lines of (Technical System) Evolution, to enable improved identification of future product and technology constructs. The Laws allow for thinking about system evolution while the Lines provide insight into implementation. These techniques are integrated to form the majority of a proposed technology identification and selection process because they provide a criteria for developing and establishing technical forecasts that is rooted in extensive study of prior inventive results.by Michael W. Frauens.S.M

    Components of performance in selecting for heterosis in swine

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    This bulletin is a report on Animal Husbandry Department project number 39 entitled 'Swine Improvement'--P. 6."This report includes much of the material presented by the senior author as a dissertation for the Doctor of Philosophy degree in July, 1952"--P. [7].Digitized 2007 AES.Includes bibliographical references (pages 67-68)
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