671 research outputs found
Lift and drag characteristics of a cabin monoplane
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
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
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 mesons
as well as the Shape Function , that enters
in the decay , 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 is identical to the so-called
Roman Shape Function. From the parameters for the latter that fit the spectrum we predict the behaviour of . We
discuss the important role played by the constituent light quark mass. In
particular, although for vanishing light quark mass, a
non-vanishing mass implies the unfamiliar result . Moreover,
we incorporate the short distance behaviour of QCD to ,
which has sizeable effects at large . We obtain the values for the
parameters GeV and
GeV. We compare with other theoretical approaches and illustrate the
great variety of models found in the literature for the functions ; 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
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
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
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
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
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
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
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
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
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