461 research outputs found

    Nucleon-Nucleon Interactions from the Quark Model

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    We report on investigations of the applicability of non-relativistic constituent quark models to the low-energy nucleon-nucleon (NN) interaction. The major innovations of a resulting NN potential are the use of the 3^3P0_0 decay model and quark model wave functions to derive nucleon-nucleon-meson form-factors, and the use of a colored spin-spin contact hyperfine interaction to model the repulsive core rather than the phenomenological treatment common in other NN potentials. We present the results of the model for experimental free NN scattering phase shifts, S-wave scattering lengths and effective ranges and deuteron properties. Plans for future study are discussed.Comment: 5 pages, 4 figures, 2 tables. To appear in Proceedings of XIII International Conference on Hadron Spectroscopy, November 29 - December 4, 2009, Florida State Universit

    NASA's New Thermal Management Systems Roadmap; Whats in it, What it Means

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    In July of 2015 NASA publically released a new set of Technology Area Roadmaps that will be used to help guide future NASA-funded technology development efforts. One of these was the Thermal Management Systems Roadmap, often identified as TA14. This Roadmap identifies the time sequencing and interdependencies of high priority, advanced thermal control technology for the next 5 to 20 years. Available funding limits the development of new technology. The Roadmaps are the first step in the process of prioritizing HQ-supported technology funding. The 2015 Roadmaps are focused on planned mission architectures and needs, as identified in the NRC-led science Decadals and HEOMD's Design Reference Missions. Additionally, the 2015 Roadmaps focus on "applied " R&D as opposed to more basic research. The NASA Mission Directorates were all closely involved in development of 2015 Roadmaps, and an extensive external review was also conducted. This talk will discuss the Technology Roadmaps in general, and then focus on the specific technologies identified for TA 14, Thermal Management Systems

    NASA/Goddard Thermal Technology Overview 2012

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    New Technology program is underway at NASA NASA/GSFC's primary mission of science satellite development is healthy and vibrant, although new missions are scarce Future mission applications promise to be thermally challenging Direct technology funding is still very restricte

    NASA Goddard Thermal Technology Overview 2018

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    This presentation summarizes the current plans and efforts at NASA/Goddard to develop new thermal control technology for anticipated future missions. It will also address some of the programmatic developments currently underway at NASA, especially with respect to the NASA Technology Development Program. The effects of the recently submitted NASA budget will also be addressed. While funding for basic technology development is still tight, significant efforts are being made in direct support of flight programs. Thermal technology Implementation on current flight programs will be reviewed, and the recent push for Cube-sat mission development will also be addressed. Many of these technologies also have broad applicability to DOD, DOE, and commercial programs. Partnerships have been developed with the Air Force, Navy, and various universities to promote technology development. In addition, technology development activities supported by internal research and development (IRAD) program and the Small Business Innovative Research (SBIR) program are reviewed in this presentation. Specific technologies addressed include; two-phase systems applications and issues on NASA missions, latest developments of thermal control coatings, Atomic Layer Deposition (ALD), Micro-scale Heat Transfer, and various other research activities

    Design and Testing of a Cryogenic Capillary Pumped Loop Flight Experiment

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    This paper details the flight configuration and pre-flight performance test results of the fifth generation cryogenic capillary pumped loop (CCPL-5). This device will fly on STS-95 in October 1998 as part of the CRYOTSU Flight Experiment. This flight represents the first in-space demonstration of a CCPL, a miniaturized two-phase fluid circulator for thermally linking cryogenic cooling sources to remote cryogenic components. CCPL-5 utilizes N2 as the working fluid and has a practical operating range of 75-110 K. Test results indicate that CCPL-5, which weighs about 200 grams, can transport over 10 W of cooling a distance of 0.25 m (or more) with less than a 5 K temperature drop

    Campus Vol IX N 2

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    Tuttle, C. Cover. Picture. 1. Howard Studio. Miss Betsy Phelps . Picture. 2. Troelstrud. Untitled. Cartoon. 4. Anonymous. Campus Calender . Picture. 5. Aaybe, Nancy. By Any Other Name . Prose. 8. Sherman, Marj. Gone Today and Gone Tomorrow . Prose. 10. Martin, Lyn. Six Weeks Old . Prose. 11. Shaw, Ted. \u27Twas The Night Before Christmas . Cartoon. 12. Bogardus, Edna. On Human Pageants . Prose. 14. Swanson, Dru. Nineveh Disclaimed . Prose. 15. Dock. Untitled. Cartoon. 15.; Curry, Chuck. Varsity Basketball . Prose. 16. Shackelford, Duck. The Freshman Rushing Primer . Prose. 18. Anonymous. Untitled. Prose. 19. Hodge, Beth. Denison\u27s Menaces . Cartoon. 20. Kull, Shaw. Untitled. Cartoon. 10. Kull, Shaw. Untitled. Cartoon. 21. Clifford, Bob. Christmas is For Everyone . Prose.23. Anonymous. Untitled. Cartoon. 23. Kull, Shaw. Untitled . Cartoon. 23

    Hawking Spectrum and High Frequency Dispersion

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    We study the spectrum of created particles in two-dimensional black hole geometries for a linear, hermitian scalar field satisfying a Lorentz non-invariant field equation with higher spatial derivative terms that are suppressed by powers of a fundamental momentum scale k0k_0. The preferred frame is the ``free-fall frame" of the black hole. This model is a variation of Unruh's sonic black hole analogy. We find that there are two qualitatively different types of particle production in this model: a thermal Hawking flux generated by ``mode conversion" at the black hole horizon, and a non-thermal spectrum generated via scattering off the background into negative free-fall frequency modes. This second process has nothing to do with black holes and does not occur for the ordinary wave equation because such modes do not propagate outside the horizon with positive Killing frequency. The horizon component of the radiation is astonishingly close to a perfect thermal spectrum: for the smoothest metric studied, with Hawking temperature TH≃0.0008k0T_H\simeq0.0008k_0, agreement is of order (TH/k0)3(T_H/k_0)^3 at frequency ω=TH\omega=T_H, and agreement to order TH/k0T_H/k_0 persists out to ω/TH≃45\omega/T_H\simeq 45 where the thermal number flux is O(10−20O(10^{-20}). The flux from scattering dominates at large ω\omega and becomes many orders of magnitude larger than the horizon component for metrics with a ``kink", i.e. a region of high curvature localized on a static worldline outside the horizon. This non-thermal flux amounts to roughly 10\% of the total luminosity for the kinkier metrics considered. The flux exhibits oscillations as a function of frequency which can be explained by interference between the various contributions to the flux.Comment: 32 pages, plain latex, 16 figures included using psfi

    Parkinson's disease biomarkers: perspective from the NINDS Parkinson's Disease Biomarkers Program

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    Biomarkers for Parkinson's disease (PD) diagnosis, prognostication and clinical trial cohort selection are an urgent need. While many promising markers have been discovered through the National Institute of Neurological Disorders and Stroke Parkinson's Disease Biomarker Program (PDBP) and other mechanisms, no single PD marker or set of markers are ready for clinical use. Here we discuss the current state of biomarker discovery for platforms relevant to PDBP. We discuss the role of the PDBP in PD biomarker identification and present guidelines to facilitate their development. These guidelines include: harmonizing procedures for biofluid acquisition and clinical assessments, replication of the most promising biomarkers, support and encouragement of publications that report negative findings, longitudinal follow-up of current cohorts including the PDBP, testing of wearable technologies to capture readouts between study visits and development of recently diagnosed (de novo) cohorts to foster identification of the earliest markers of disease onset

    The Induction of Autoimmune Arthritis and Sex differences in Mice Impact the Lung Inflammatory Response to Repetitive Inhalant Organic Dust Extract Exposures

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    Asthma, chronic bronchitis and COPD are common adverse respiratory health effects among persons exposed to agriculture organic dust work environments. Occupational inhalant exposures have been increasingly associated with the risk of rheumatoid arthritis (RA) disease development, particularly among males. Agriculture workers have increased risk of RA and generalized bone disease. Chronic lung disease is associated with production of characteristic autoantibodies associated with RA (e.g.anti-citrullinated antibodies), even in absence of RA disease. The mechanistic link between pulmonary inflammation and arthritis (and vice versa) remains poorly understood. Animal models are lacking.https://digitalcommons.unmc.edu/emet_posters/1004/thumbnail.jp
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