671 research outputs found

    Lift and drag characteristics of a cabin monoplane

    Get PDF
    The results of flight tests conducted by the NACA to determine the lift and drag characteristics of a full-scale airplane are given herein. A Fairchild FC-2W2 cabin monoplane having a Gottingen 387 wing section was used for the tests. The maximum lift coefficient for the airplane is compared with that obtained for the Gottingen 387 airfoil in recent tests in the Variable Density Tunnel. The maximum lift coefficient for the airplane was found to be 1.50 and that for the airfoil 1.56. Although the flight tests were confined chiefly to glides with the propeller locked horizontally, data obtained with the propeller operating at zero thrust for a few angles of attack are also included

    Optical propagation measurements at Emerson Lake, 1968

    Get PDF
    Optical propagation measurements in inhomogeneous atmosphere at Emerson Lake, California for optical propagation theory validity testin

    Relation between Light Cone Distribution Amplitudes and Shape Function in B mesons

    Full text link
    The Bakamjian-Thomas relativistic quark model provides a Poincar\'e representation of bound states with a fixed number of constituents and, in the heavy quark limit, form factors of currents satisfy covariance and Isgur-Wise scaling. We compute the Light Cone Distribution Amplitudes of BB mesons ϕ±B(ω)\phi_{\pm}^B(\omega) as well as the Shape Function S(ω)S(\omega), that enters in the decay BXsγB \to X_s \gamma, that are also covariant in this class of models. The LCDA and the SF are related through the quark model wave function. The former satisfy, in the limit of vanishing constituent light quark mass, the integral relation given by QCD in the valence sector of Fock space. Using a gaussian wave function, the obtained S(ω)S(\omega) is identical to the so-called Roman Shape Function. From the parameters for the latter that fit the BXsγB \to X_s\gamma spectrum we predict the behaviour of ϕ±B(ω)\phi_{\pm}^B(\omega). We discuss the important role played by the constituent light quark mass. In particular, although ϕB(0)0\phi_-^B(0) \not= 0 for vanishing light quark mass, a non-vanishing mass implies the unfamiliar result ϕB(0)=0\phi_-^B (0) = 0. Moreover, we incorporate the short distance behaviour of QCD to ϕ+B(ω)\phi_+^B (\omega), which has sizeable effects at large ω\omega. We obtain the values for the parameters Λˉ0.35\bar{\Lambda} \cong 0.35 GeV and λB11.43\lambda_B^{-1} \cong 1.43 GeV1^{-1}. We compare with other theoretical approaches and illustrate the great variety of models found in the literature for the functions ϕ±B(ω)\phi_{\pm}^B (\omega); hence the necessity of imposing further constraints as in the present paper. We briefly review also the different phenomena that are sensitive to the LCDA.Comment: 6 figure

    Relativistic quantum theories and neutrino oscillations

    Full text link
    Neutrino oscillations are examined under the broad requirements of Poincar\'e-invariant scattering theory in an S-matrix formulation. This approach can be consistently applied to theories with either field or particle degrees of freedom. The goal of this paper is to use this general framework to identify all of the unique physical properties of this problem that lead to a simple oscillation formula. We discuss what is in principle observable, and how many factors that are important in principle end up being negligible in practice.Comment: 21 pages, no figure

    Axial-vector mesons in a relativistic point-form approach

    Full text link
    The Poincare invariant coupled-channel formalism for two-particle systems interacting via one-particle exchange, which has been developed and applied to vector mesons in Ref. [1] is applied to axial vector mesons. We thereby extend the previous study of a dynamical treatment of the Goldstone-boson exchange by comparison with the commonly used instantaneous approximation to the case of orbital angular momentum l=1. Effects in the mass shifts show more variations than for the vector-meson case. Results for the decay widths are sizable, but comparison with sparse experimental data is inconclusive.Comment: 4 pages, 1 figur

    Mimesis stories: composing new nature music for the shakuhachi

    Get PDF
    Nature is a widespread theme in much new music for the shakuhachi (Japanese bamboo flute). This article explores the significance of such music within the contemporary shakuhachi scene, as the instrument travels internationally and so becomes rooted in landscapes outside Japan, taking on the voices of new creatures and natural phenomena. The article tells the stories of five compositions and one arrangement by non-Japanese composers, first to credit composers’ varied and personal responses to this common concern and, second, to discern broad, culturally syncretic traditions of nature mimesis and other, more abstract, ideas about the naturalness of sounds and creative processes (which I call musical naturalism). Setting these personal stories and longer histories side by side reveals that composition creates composers (as much as the other way around). Thus it hints at much broader terrain: the refashioning of human nature at the confluence between cosmopolitan cultural circulations and contemporary encounters with the more-than-human world

    Rotational covariance and light-front current matrix elements

    Full text link
    Light-front current matrix elements for elastic scattering from hadrons with spin~1 or greater must satisfy a nontrivial constraint associated with the requirement of rotational covariance for the current operator. Using a model ρ\rho meson as a prototype for hadronic quark models, this constraint and its implications are studied at both low and high momentum transfers. In the kinematic region appropriate for asymptotic QCD, helicity rules, together with the rotational covariance condition, yield an additional relation between the light-front current matrix elements.Comment: 16 pages, [no number

    Spectator-model operators in point-form relativistic quantum mechanics

    Full text link
    We address the construction of transition operators for electromagnetic, weak, and hadronic reactions of relativistic few-quark systems along the spectator model. While the problem is of relevance for all forms of relativistic quantum mechanics, we specifically adhere to the point form, since it preserves the spectator character of the corresponding transition operators in any reference frame. The conditions imposed on the construction of point-form spectator-model operators are discussed and their implications are exemplified for mesonic decays of baryon resonances within a relativistic constituent quark model.Comment: 10 pages, 4 figures, updated version accepted for publication in Europ. Phys. J.

    The Balian-Br\'ezin Method in Relativistic Quantum Mechanics

    Full text link
    The method suggested by Balian and Br\'ezin for treating angular momentum reduction in the Faddeev equations is shown to be applicable to the relativistic three-body problem.Comment: 14 pages in LaTe

    Automated Syringe Filler

    Get PDF
    The automated syringe filling system is a bench-top device designed to remove human error when filling a syringe. The microcontroller powered system will hold multiple medicine types that will fill a single syringe with a user specified amount of one medicine to a precise degree and log this information against a remote database of patient information. Before the system can be accessed, the user’s credentials will be checked against the database of authorized users. Once verified a touch screen will be used to enter user input that will be logged to a remote database. The microcontroller will then control the actuators and servo to fill the syringe with the appropriate amount of medicine. The system will automate the process of filling a syringe and remove the element of human error from the syringe filling equation
    corecore