5,287 research outputs found
Reduced dimension modeling of leading edge turbulent interaction noise
A computational aeroacoustics approach is used to model the effects of real airfoil geometry on leading edge turbulent interaction noise for symmetric airfoils at zero angle of attack. For the first time, one-component (transverse), two-component (transverse and streamwise), and three-component (transverse, streamwise, and spanwise) synthesized turbulent disturbances are modeled instead of single frequency transverse gusts, which previous computational studies of leading edge noise have been confined to. The effects of the inclusion of streamwise and spanwise disturbances on the noise are assessed, and it is shown that accurate noise predictions for symmetric airfoils can be made by modeling only the transverse disturbances, which reduces the computational expense of simulations. Additionally, the two-component turbulent synthesis method is used to model the effects of airfoil thickness on the noise for thicknesses ranging from 2% to 12%. By using sufficient airfoil thicknesses to show trends, it is found that airfoil thickness will reduce the noise at high frequency, and that the sound power P will reduce linearly with increasing airfoil thickness
Larceny of Referendum Petitions (concluded)
It would seem that from the very outset the Supreme Court of Missouri refused to accept the common law as to larceny of choses in action. In State v. Newell there was an indictment for obtaining bills of exchange by false pretenses
LEGAL CONTROL OF MEDICAL PRACTICE: VALIDITY AND METHODS
Legislators have deemed it necessary, in order to protect the public interest, to exercise some control over the practice of the healing art by physicians, surgeons, chiropractors, osteopaths, dentists, etc., both as to who may practice and in what manner the practice may be carried on. Legislators have also required, in certain situations, that designated persons submit to medical treatment. Both types of regulation give rise to various legal and constitutional problems and it is the purpose of this paper to discuss some of these problems
Larceny of Referendum Petitions
It seems reasonably certain that the English courts have never considered the absurd and indefensible rule relating to choses in action as applying to all written instruments. Indeed, Regina v. Morrison, supra, refuses to apply the rule to an instrument that was evidence of an obligation between parties. Is it not curious that an English court in the middle of the nineteenth century is found to be restricting its doctrine while an American court in the twentieth century is attempting to extend a transplanted and anarchronistic notion that rests on a fiction which is socially inexpedient
Incoherent dynamics in neutron-matter interaction
Coherent and incoherent neutron-matter interaction is studied inside a
recently introduced approach to subdynamics of a macrosystem. The equation
describing the interaction is of the Lindblad type and using the Fermi
pseudopotential we show that the commutator term is an optical potential
leading to well-known relations in neutron optics. The other terms, usually
ignored in optical descriptions and linked to the dynamic structure function of
the medium, give an incoherent contribution to the dynamics, which keeps
diffuse scattering and attenuation of the coherent beam into account, thus
warranting fulfilment of the optical theorem. The relevance of this analysis to
experiments in neutron interferometry is briefly discussed.Comment: 15 pages, revtex, no figures, to appear in Phys. Rev.
Energetics and dynamics of H adsorbed in a nanoporous material at low temperature
Molecular hydrogen adsorption in a nanoporous metal organic framework
structure (MOF-74) was studied via van der Waals density-functional
calculations. The primary and secondary binding sites for H were confirmed.
The low-lying rotational and translational energy levels were calculated, based
on the orientation and position dependent potential energy surface at the two
binding sites. A consistent picture is obtained between the calculated
rotational-translational transitions for different H loadings and those
measured by inelastic neutron scattering exciting the singlet to triplet (para
to ortho) transition in H. The H binding energy after zero point energy
correction due to the rotational and translational motions is predicted to be
100 meV in good agreement with the experimental value of 90 meV.Comment: 5 pagers, 4 figures. added reference
Ideal Gas in a strong Gravitational field: Area dependence of Entropy
We study the thermodynamic parameters like entropy, energy etc. of a box of
gas made up of indistinguishable particles when the box is kept in various
static background spacetimes having a horizon. We compute the thermodynamic
variables using both statistical mechanics as well as by solving the
hydrodynamical equations for the system. When the box is far away from the
horizon, the entropy of the gas depends on the volume of the box except for
small corrections due to background geometry. As the box is moved closer to the
horizon with one (leading) edge of the box at about Planck length (L_p) away
from the horizon, the entropy shows an area dependence rather than a volume
dependence. More precisely, it depends on a small volume A*L_p/2 of the box,
upto an order O(L_p/K)^2 where A is the transverse area of the box and K is the
(proper) longitudinal size of the box related to the distance between leading
and trailing edge in the vertical direction (i.e in the direction of the
gravitational field). Thus the contribution to the entropy comes from only a
fraction O(L_p/K) of the matter degrees of freedom and the rest are suppressed
when the box approaches the horizon. Near the horizon all the thermodynamical
quantities behave as though the box of gas has a volume A*L_p/2 and is kept in
a Minkowski spacetime. These effects are: (i) purely kinematic in their origin
and are independent of the spacetime curvature (in the sense that Rindler
approximation of the metric near the horizon can reproduce the results) and
(ii) observer dependent. When the equilibrium temperature of the gas is taken
to be equal to the the horizon temperature, we get the familiar A/L_p^2
dependence in the expression for entropy. All these results hold in a D+1
dimensional spherically symmetric spacetime.Comment: 19 pages, added some discussion, matches published versio
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