13,941 research outputs found
On the flow processes in sharply inclined and stalled airfoils in parallel movement and rotation
The purpose of this study is to obtain a deeper insight into the complicated flow processes on airfoils in the region of the buoyancy maxima. To this end calculated and experimental investigations are carried out on a straight stationary, a twisted stationary and a straight rotating rectangular wing. According to the available results the method gives results which can be applied sufficiently for flow applied firmly on all sides for all rotation values. The reliability of the method may be questioned for a flow undergoing transition from the attached to the separated state or for totally separated flow and higher rotation values
2-16 mu m spectroscopy of micron-sized enstatite (Mg,Fe)(2)Si2O6 silicates from primitive chondritic meteorites
We present mid-infrared spectra from individual enstatite silicate grains separated from primitive type 3 chondritic meteorites. The 2-16 mu m transmission spectra were taken with microspectroscopic Fourier-transform infrared (FT-IR) techniques as part of a project to produce a data base of infrared spectra from minerals of primitive meteorites for comparison with astronomical spectra. In general, the wavelength of enstatite bands increases with the proportion of Fe. However, the wavelengths of the strong En(100) bands at 10.67 and 11.67 decrease with increasing Fe content. The 11.67-mu m band exhibits the largest compositional wavelength shift (twice as large as any other). Our fits of the linear dependence of the pyroxene peaks indicate that crystalline silicate peaks in the 10-mu m spectra of Herbig AeBe stars, HD 179218 and 104237, are matched by pyroxenes of En(90-92) and En(78-80), respectively. If these simplistic comparisons with the astronomical grains are correct, then the enstatite pyroxenes seen in these environments are more Fe-rich than are the forsterite (Fo(100)) grains identified in the far-infrared which are found to be Mg end-member grains. This differs from the general composition of type 3 chondritic meteoritic grains in which the pyroxenes are more Mg-rich than are the olivines from the same meteorite
Crew training program for LTA-8 thermal vacuum test
Crew training program for lunar module thermal vacuum testin
Local Out-Tournaments with Upset Tournament Strong Components I: Full and Equal {0,1}-Matrix Ranks
A digraph D is a local out-tournament if the outset of every vertex is a tournament. Here, we use local out-tournaments, whose strong components are upset tournaments, to explore the corresponding ranks of the adjacency matrices. Of specific interest is the out-tournament whose adjacency matrix has boolean, nonnegative integer, term, and real rank all equal to the number of vertices, n. Corresponding results for biclique covers and partitions of the digraph are provided
Entanglement and Disentanglement in Circuit QED Architectures
We propose a protocol for creating entanglement within a dissipative circuit
QED network architecture that consists of two electromagnetic circuits
(cavities) and two superconducting qubits. The system interacts with a quantum
environment, giving rise to decoherence and dissipation. We discuss the
preparation of two separate entangled cavity-qubit states via Landau-Zener
sweeps, after which the cavities interact via a tunable "quantum switch" which
is realized with an ancilla qubit. Moreover, we discuss the decay of the
resulting entangled two-cavity state due to the influence of the environment,
where we focus on the entanglement decay.Comment: 7 pages, 5 figure
Coherence stabilization of a two-qubit gate by AC fields
We consider a CNOT gate operation under the influence of quantum bit-flip
noise and demonstrate that ac fields can change bit-flip noise into phase noise
and thereby improve coherence up to several orders of magnitude while the gate
operation time remains unchanged. Within a high-frequency approximation, both
purity and fidelity of the gate operation are studied analytically. The
numerical treatment with a Bloch-Redfield master equation confirms the
analytical results.Comment: 4 pages, 2 figure
Why the Tsirelson Bound? Bub's Question and Fuchs' Desideratum
To answer Wheeler's question "Why the quantum?" via quantum information
theory according to Bub, one must explain both why the world is quantum rather
than classical and why the world is quantum rather than superquantum, i.e.,
"Why the Tsirelson bound?" We show that the quantum correlations and quantum
states corresponding to the Bell basis states, which uniquely produce the
Tsirelson bound for the Clauser-Horne-Shimony-Holt quantity, can be derived
from conservation per no preferred reference frame (NPRF). A reference frame in
this context is defined by a measurement configuration, just as with the light
postulate of special relativity. We therefore argue that the Tsirelson bound is
ultimately based on NPRF just as the postulates of special relativity. This
constraint-based/principle answer to Bub's question addresses Fuchs'
desideratum that we "take the structure of quantum theory and change it from
this very overt mathematical speak ... into something like [special
relativity]." Thus, the answer to Bub's question per Fuchs' desideratum is,
"the Tsirelson bound obtains due to conservation per NPRF."Comment: Contains corrections to the published versio
Weyl formulas for annular ray-splitting billiards
We consider the distribution of eigenvalues for the wave equation in annular
(electromagnetic or acoustic) ray-splitting billiards. These systems are
interesting in that the derivation of the associated smoothed spectral counting
function can be considered as a canonical problem. This is achieved by
extending a formalism developed by Berry and Howls for ordinary (without
ray-splitting) billiards. Our results are confirmed by numerical computations
and permit us to infer a set of rules useful in order to obtain Weyl formulas
for more general ray-splitting billiards
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