907 research outputs found
Interactive aircraft flight control and aeroelastic stabilization
Get PDFSeveral examples are presented in which flutter involving interaction between flight mechanics modes and elastic wind bending occurs for a forward swept wing flight vehicle. These results show the basic mechanism by which the instability occurs and form the basis for attempts to actively control such a vehicle
Dynamics and control of forward swept wing aircraft
Get PDFAspects of non-zero differential game theory with application to multivariable control synthesis and optimal linear control law design using optimum parameter sensitivity analysis are discussed
An exact plane-stress solution for a class of problems in orthotropic elasticity
Get PDFAn exact solution for the stress field within a rectangular slab of orthotropic material is found using a two dimensional Fourier series formulation. The material is required to be in plane stress, with general stress boundary conditions, and the principle axes of the material must be parallel to the sides of the rectangle. Two load cases similar to those encountered in materials testing are investigated using the solution. The solution method has potential uses in stress analysis of composite structures
Electrochemical method of controlling thiolate coverage on a conductive substrate such as gold
Get PDFAn electrochemical method for forming a partial monomolecular layer of a predetermined extent of coverage of a thiolate of the formula, XRS--, therein R can be a linear or branched chain hydrocarbon or an aromatic or the like and X can be any compatible end group, e.g., OH, COOH, CH.sub.3 or the like, upon a substrate such as gold, which involves applying in an electrochemical system a constant voltage preselected to yield the desired predetermined extent of coverage
Linear polarization sensitivity of SeGA detectors
Get PDFParity is a key observable in nuclear spectroscopy. Linear polarization
measurements of -rays are a probe to access the parities of energy
levels. Utilizing the segmentation of detectors in the Segmented Germanium
Array (SeGA) at the NSCL and analyzing the positions of interaction therein
allows the detectors to be used as Compton polarimeters. Unlike other segmented
detectors, SeGA detectors are irradiated from the side to utilize the
transversal segmentation for better Doppler corrections. Sensitivity in such an
orientation has previously been untested. A linear polarization sensitivity has been measured in the 350-keV energy range for SeGA detectors
using - correlations from a \nuc{249}{Cf} source.Comment: 7 pages, 9 figure
Is the structure of 42Si understood?
Get PDFA more detailed test of the implementation of nuclear forces that drive shell
evolution in the pivotal nucleus \nuc{42}{Si} -- going beyond earlier
comparisons of excited-state energies -- is important. The two leading
shell-model effective interactions, SDPF-MU and SDPF-U-Si, both of which
reproduce the low-lying \nuc{42}{Si}() energy, but whose predictions for
other observables differ significantly, are interrogated by the population of
states in neutron-rich \nuc{42}{Si} with a one-proton removal reaction from
\nuc{43}{P} projectiles at 81~MeV/nucleon. The measured cross sections to the
individual \nuc{42}{Si} final states are compared to calculations that combine
eikonal reaction dynamics with these shell-model nuclear structure overlaps.
The differences in the two shell-model descriptions are examined and linked to
predicted low-lying excited states and shape coexistence. Based on the
present data, which are in better agreement with the SDPF-MU calculations, the
state observed at 2150(13)~keV in \nuc{42}{Si} is proposed to be the ()
level.Comment: accepted in Physical Review Letter
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