26,939 research outputs found

    Review of N N Interaction from Lattice QCD

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    Historically, lattice studies of QCD have concentrated on understanding the properties and structure of an isolated hadron. Recently, there have efforts at understanding the interactions between hadrons. In this talk I will review two approaches to this problem.Comment: 2 pages, 1 postscript figure. To appear in proceedings of Chiral Dynamics 2000, Jefferson Laboratory, July 17-22, 200

    Threshold Resonances - a Lattice Perspective

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    The calculation of the masses of the lightest nucleon resonances using lattice QCD is surveyed. Recent results for the mass of the first radial excitation of the nucleon, the Roper resonance, are reviewed and the interpretation in terms of models of hadronic resonances, such as the quark model and hadronic molecules, discussed. The talk concludes with an outline of prospects for future calculations.Comment: 5 Pages, 2 figures, invited contribution to Focus Session on Nature of Threshold N*, to be published in Proceedings of NSTAR 2002, Pittsburgh, October 9-12, 2002 (World Scientific

    Ride quality evaluation 1: Questionnaire studies of airline passenger comfort

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    As part of a larger effort to assess passenger comfort in aircraft, two questionnaires were administered: one to ground-based respondents; the other to passengers in flight. Respondents indicated the importance of various factors influencing their satisfaction with a trip, the perceived importance of various physical factors in determining their level of comfort, and the ease of time spent performing activities in flight. The in-flight sample also provided a rating of their level of comfort and of their willingness to fly again. Comfort ratings were examined in relation to (1) type of respondent, (2) type of aircraft, (3) characteristics of the passengers, (4) ease of performing activities, and (5) willingness to fly again

    Passenger ride quality determined from commercial airline flights

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    The University of Virginia ride-quality research program is reviewed. Data from two flight programs, involving seven types of aircraft, are considered in detail. An apparatus for measuring physical variations in the flight environment and recording the subjective reactions of test subjects is described. Models are presented for predicting the comfort response of test subjects from the physical data, and predicting the overall comfort reaction of test subjects from their moment by moment responses. The correspondence of mean passenger comfort judgments and test subject response is shown. Finally, the models of comfort response based on data from the 5-point and 7-point comfort scales are shown to correspond

    Application of ride quality technology to predict ride satisfaction for commuter-type aircraft

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    A method was developed to predict passenger satisfaction with the ride environment of a transportation vehicle. This method, a general approach, was applied to a commuter-type aircraft for illustrative purposes. The effect of terrain, altitude and seat location were examined. The method predicts the variation in passengers satisfied for any set of flight conditions. In addition several noncommuter aircraft were analyzed for comparison and other uses of the model described. The method has advantages for design, evaluation, and operating decisions

    Lattice Gauge Theory - QCD from Quarks to Hadrons

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    Lattice Gauge Theory enables an ab initio study of the low-energy properties of Quantum Chromodynamics, the theory of the strong interaction. I begin these lectures by presenting the lattice formulation of QCD, and then outline the benchmark calculation of lattice QCD, the light-hadron spectrum. I then proceed to explore the predictive power of lattice QCD, in particular as it pertains to hadronic physics. I will discuss the spectrum of glueballs, exotics and excited states, before investigating the study of form factors and structure functions. I will conclude by showing how lattice QCD can be used to study multi-hadron systems, and in particular provide insight into the nucleon-nucleon interaction.Comment: 43 Pages, 20 Figures, Proceedings of 14th. Annual Hampton University Graduate Studies at CEBAF, June 1 - 18, 1999 Minor correction in removal of one figur
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