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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Quadrupole splitting of Na 23 nuclear magnetic resonance /NMR/ to investigate spontaneous polarization, coercive field and domain characteristics in Rochelle salt ferroelectric phase
Wave propagation in warm uniaxial plasma filled waveguide, analyzing TE modes, TM mode splitting and power transfer
Branched trajectory optimization for split rocket vehicles using projected gradient or steepest descent method
NOL ring split-dee tensile test has the advantages that the specimen is readily fabricated by winding and the test is performed in a conventional testing machine without special fixtures. Strain gages cannot be mounted, however, and substantial bending moments are introduced.
Split ring, angular-contact bearing has only one ball path on the inner race and the outer race. Upon failure of either races or balls, bearing is reversed in its housing so that force is applied to opposite points on the races and bearing operation is unaffected by previous failure.
Circuitry requires modulated subcarrier to be split, part going to a phase modulator, and part going to a new circuit which utilizes a square law detector, a balanced mixer, and an amplifier to remove spurious sidebands. A summer recombines the two outputs, and final signal no longer includes spures.
Design, fabrication, and functional testing of brushless dc motors with split winding connected in series or parallel
Isomer shift, Mossbauer recoil free fraction and nuclear quadrupole splitting for Fe57 in iron fluoride measured for lattice dynamics, fine and hyperfine structure
Branched trajectory optimization for split rocket vehicles using projected gradient or steepest descent method
Fe 57 nuclear hyperfine splittings in clinopyroxenes from lunar igneous rocks, determining temperature dependent cation distribution
Design analysis for split flow reaction turbine for SNAP 8 system
Optical hyperfine splitting of Rb resonance lines of atomic beam light source, using Fabry-Perot interferometer
Zero field hyperfine splitting in carbon trifluorobromide photodissociation laser emission
Split nut with internal taper to hold specially formed specimen composed of filaments of refractory material provides means for holding at high temperature and under tension so that performance evaluations may be made.
Numerical determination of flux components in vapor flow considers split boundary conditions in both directions to form grid lines for flow continuity equations. Matrix of coefficients obtains direct solution for potential flow problem without iteration.
A split-core heat pipe reactor, fueled with either U(233)C or U(235)C in a tungsten cermet and cooled by 7-Li-W heat pipes, was examined for the effects of the heat pipes on reactor while trying to safely absorb large reactivity inputs through inherent shutdown mechanisms. Limits on ramp reactivity inputs due to fuel melting temperature and heat pipe wall heat flux were mapped for the reactor in both startup and at-power operating modes.
The theory of optimal control for nonscalar-valued performance criteria is discussed. In the space, where the performance criterion attains its value, the relations better than, worse than, not better than, and not worse than are defined by a partial order relation. The notion of optimality splits up into superiority and non-inferiority, because worse than is not the complement of better than, in general. A superior solution is better than every other solution. A noninferior solution is not worse than any other solution. Noninferior solutions have been investigated particularly for vector-valued performance criteria. Superior solutions for non-scalar-valued performance criteria attaining their values in abstract partially ordered spaces are emphasized. The main result is the infimum principle which constitutes necessary conditions for a control to be a superior solution to an optimal control problem.
A detailed experimental and theoretical study of quantum oscillations in the magnetostriction and Young's modulus of p-PbTe is presented. The valance band of PbTe is approximated by a spheroidal, nonparabolic model in which the effects of strain on the valance band parameters are described by a deformation potential model. Using appropriate thermodynamic derivatives of the modified Lifshitz-Kosevich expression for the oscillatory parts of the electronic free energy, it is shown that both types of oscillations arise mainly from relative shifts of the valance band maxima due to shear strains, accompanied by intervalley charge transfer. Band parameters derived from the periods, phases, and spin splitting of the oscillations are in generally good agreement with values reported by other workers. A detailed comparison is made of the experimentally observed oscillation amplitudes with those predicted by theory, and satisfactory agreement is found. The ratio of the amplitudes of the two effects yields a value of the valance band deformation potential in good agreement with a value found from piezoresistance experiments by Burke.