2,474 research outputs found

    Solar Polar Explorer Enabling Launch Technology

    Get PDF
    To unlock mysteries of our sun, Southwest Research Institute (SwRI) and its propulsion system partner Northrop Grumman confronted the challenge of getting sensors to the sun for detailed observation on a limited budget. SwRI’s proposed Solaris mission paired a solar observatory with the Orion 38 and Orion 50 XLT Solid Rocket Motor (SRM)-based stages for a gravity-assisted slingshot maneuver around Jupiter. The NASA Heliophysics Medium Explorer (MIDEX) program selected Solaris in 2020 for a concept study that ran through 2022. Solaris aimed to conduct high-latitude observations of the Sun’s south and north regions to resolve our understanding of how their magnetic fields and flows effect the broader solar cycle. Solaris carried two primary sensors: a Compact Doppler Magnetograph (CDM); and a wide-field Solaris Extreme Ultraviolet Imager (S-EUVI). The proposal conformed to cost and launch vehicle parameters: a $250 million MIDEX mission cost cap and integration with one of three Designated Reference Launch Vehicles (DRLVs). The launch vehicle did not count toward the mission cost but the velocity-boosting upper stage motors did. The cost and technical tradeoffs resulting in Solaris being paired with the Orion 38 and Orion 50 XLT SRM-based stages are likely relevant to other cost-capped deep space missions

    The Meaning of the Changes within the Framework of Subchapter C and the Impact on Proposals for Integration of the Corporate and Individual Tax

    Get PDF
    Professor Cohen warns against an easy acceptance of repeal of General Utilities and other aspects of the Staff Proposal. He believes that the problem can be more fruitfully discussed in the context of an integrated form of tax, where double tax burdens are ameliorated. Professors Warren and Andrews discuss two proposals for restructuring the tax consequences of corporate distributions and the integration of the individual and corporate income taxes, as a means of eliminating double tax burdens and other inequities, and the American Law Institute Reporter\u27s Study

    The effect of lifting straps on peak velocity, force, and power during clean pull

    Get PDF
    The clean pull is a common exercise among athletes. Some athletes use lifting straps in this exercise, but efficacy of lifting straps has not been examined. The purpose of the present study was to examine the effects of lifting straps on velocity, force and power during the clean pull. Five male professional Rugby Union players performed two sets of two repetitions of the clean pull with a 140-kg barbell under two conditions: with and without the lifting straps, in a counterbalanced order. An optical encoder was attached to the barbell, and peak velocity of the barbell, and force / power applied to the barbell were obtained through an inverse dynamics approach. The highest value amongst four trials (two sets of two repetitions) in each condition for each subject was used to compare between the two conditions by effect size. Four out of five subjects showed greater peak velocity (10.1-28.5%), force (2.9-34.4%), and power (6.5-46.5%) with the lifting straps, but one subject did not show a difference between conditions. The effect sizes for the velocity, force, and power were 1.22, 1.52, and 1.31, respectively, showing large effects. It is concluded that using lifting straps is beneficial for athletes who wish to enhance velocity, force and power during clean pull

    PET and P300 Relationships in Early Alzheimer\u27s Disease

    Full text link
    The P300 (P3) wave of the auditory brain event-related potential was investigated in patients with probable Alzheimer\u27s disease to determine whether P300 latency discriminated these patients from controls and whether prolonged P300 latency correlated with rates of brain glucose metabolism as measured by Positron Emission Tomography. P300 latency was prolonged by more than 1.5 standard deviations from age expectancy in 14 of 18 patients, but none of 17 controls. In these subjects P300 latency was shown to be inversely correlated with relative metabolic rates of parietal and, to a lesser extent, temporal and frontal association areas, but not with subcortical areas

    Crossing the Educational Rubicon without the TAH: Collaboration among University and Secondary-Level History Educators

    Get PDF
    In April 2011, Congress slashed funding for a majority of programs tied to education. Several programs related to professional development for teachers did not survive. While cut severely—from 119millioninFiscalYear2010to119 million in Fiscal Year 2010 to 46 million (a loss of $73 million or 61% of its funding)—Teaching American History (TAH) grants lived, albeit by their fingertips, another day. Yet, given the economic challenges the United States faces and what appear to be prevailing attitudes in regard to social services and teacher development, it has become clear that history educators cannot rely on federal funding to support efforts to improve the teaching of history. Nevertheless, meaningful collaboration among K-12 teachers and academic and public historians continues to be vital. This essay describes in detail a current collaborative relationship between a history department and high school in western Michigan. Focusing specifically on four levels of interlocking benefits of collaboration—benefits for high school teachers, for teaching candidates, for high school students, and for historians—the essay documents the strengths of this collaborative effort and notes areas where purposeful concentration and improvement might benefit all parties. Significantly, the relationship examined here, between the history department at Western Michigan University (WMU) and Portage Central High School (PCHS), developed without a promise or expectation of financial incentives. It demonstrates that collaboration, while challenging, can survive in the twenty-first century without funding from a TAH grant

    Can a specific neck strengthening program decrease cervical spine injuries in a men\u27s professional rugby union team? A retrospective analysis

    Get PDF
    Cervical spine injuries in Rugby Union are a concerning issue at all levels of the game. The primary aim of this retrospective analysis conducted in a professional Rugby Union squad was to determine whether a 26-week isometric neck strengthening intervention program (13-week strengthening phase and 13- week maintenance phase) was effective in reducing the number and severity of cervical spine injuries. The secondary aim was to determine whether at week five, where the program had been the similar for all players, there was increased isometric neck strength. All 27 players who were common to both the 2007- 2008 and 2008-2009 seasons were included in this analysis and data was extracted from a Sports Medicine/Sports Science database which included the squad\u27s injury records. Primary outcome variables included; the number of cervical spine injuries and the severity of these injuries as determined by the total number of days lost from training and competition. Secondary outcome variables included isometric neck strength in flexion, extension and left and right lateral flexion. Using nonparametric statistical methods, no significant differences were evident for the total number of cervical spine injuries (n = 8 in 2007-2008, n = 6 in 2008-2009) or time loss due to these injuries (100 days in 2007-2008, 40 days in 2008-2009). However, a significant (p = 0.03) reduction in the number of match injuries was evident from 2007-2008 (n = 11) to 2008-09 (n = 2). Nonsignificant increases in isometric neck strength were found in all directions examined. A significant reduction in the number of match injuries was evident in this study. However, no other significant changes to primary outcome variables were achieved. Further, no significant increases in isometric neck strength were found in this well-trained group of professional athletes

    Chemical spray pyrolysis of Tl-Ba-Ca-Cu-O high-T(sub c) superconductors for high-field bitter magnets

    Get PDF
    The deposition of Tl-Ba-Ca-Cu-O thick films by spray pyrolyzing a Ba-Ca-Cu-O precursor film and diffusing thallium into the film to form the superconducting phase is examined. This approach was taken to reduce exposure to thallium and its health and safety hazards. The Tl-Ba-Ca-Cu-O system was selected because it has very attractive features which make it appealing to device and manufacturing engineering. Tl-Ba-Ca-Cu-O will accommodate a number of superconducting phases. This attribute makes it very forgiving to stoichiometric fluctuations in the bulk and film. It has excellent thermal and chemical stability, and appears to be relatively insensitive to chemical impurities. Oxygen is tightly bound into the systems, consequently there is no orthorhombic (conductor) to tetragonal (insulator) transition which would affect a component's lifetime. More significantly, the thallium based superconductors appear to have harder magnetic properties than the other high-Tc oxide ceramics. Estimates using magnetoresistance measurements indicate that at 77 K Tl2Ba2CaCu2O10 will have an upper critical field, H(sub c2) fo 26 Tesla for applied fields parallel to the c-axis and approximately 1000 Tesla for fields oriented in the a-b plane. Results to date have shown that superconducting films can be reproducibly deposited on 100 oriented MgO substrates. One film had a zero resistance temperature of 111.5 K. Furthermore, x ray diffraction analysis of the films showed preferential c-axis orientation parallel to the plane of the substrate. These results have now made it possible to consider the manufacture of a superconducting tape wire which can be configured into a topology useful for high-field magnet designs. The research which leads to the preparation of these films and plans for further development are reviewed
    • …
    corecore