Circularly polarized visible light from Jupiter
Jupiter circularly polarized visible light measurements, using photoelastic polarimeter
Kemp, J. C.↗
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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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Effect of boundary layer on the transmission and attenuation of sound in an acoustically treated circular duct
Boundary layer effect on sound transmission in acoustically treated circular duct with shear flow, reducing governing equations to two-point boundary value problem
Eversman, W.↗
Optimization criterion for illuminating circular antenna apertures
Worst case criterion for finite circular antenna aperture illuminations effectiveness comparison and optimization in synthesizing ideal radiation pattern
Holland, R.↗
Circular polarization - Jupiter and other planets
Scattered light circular polarization data from Jupiter and other planets indicating nonmagnetic origin
Kemp, J. C.↗
FORTRAN program for computing coordinates of circular-arc, single and tandem, turbine and compressor, blade sections on a plane
Coordinates for circular arc blade section of aircraft high speed compressor gas turbines were computed using FORTRAN 4 program. Aerodynamic configurations studied include single segment airfoils, airfoils with slots, and mutiple segment tandem arranged airfoil.
Mcnally, W. D.↗
Computer program for calculating supersonic flow about circular, elliptic, and bielliptic cones by the method of lines
A user's manual for a computer program which calculates the supersonic flow about circular, elliptic, and bielliptic cones at incidence and elliptic cones at yaw by the method of lines is presented. The program is automated to compute a case from known or easily calculated solution by changing the parameters through a sequence of steps. It provides information including the shock shape, flow field, isentropic surface properties, entropy layer, and force coefficients. A description of the program operation, sample computations, and a FORTRAN 4 listing are presented.
Klunker, E. B.↗
Experimental investigation of circular, flat, grooved and plain steel diaphragms bursting into a 30.5-centimeter-square section
Limited data on the bursting of circular, initially flat, grooved and plain steel diaphragms opening into a 30.5-cm-square section are presented in tabular form. In addition, these data were used to determine values of an empirical constant to be used in a design equation for predicting diaphragm bursting pressures and opening times.
Yamaki, Y.↗
Systematic two-dimensional cascade tests. Volume 3: Slotted double circular-arc hydrofoils
Performance parameters are presented for cascades of slotted double circular-arc hydrofoils tested over a range of systematically introduced variables in a rectilinear cascade tunnel which uses water as the test medium. Cascade configurations included various combinations of an inlet flow angle of 50, 60 and 70 deg; a cascade solidity of 0.75, 1.00 and 1.50; a hydrofoil camber angle of 20, 30, 40 and 45 deg; and angles of incidence between positive and negative stall. The slot was positioned at the 45 percent chord station and the slot exit width was 0.047-in. Tests were also performed with the slot positioned at the 35 percent chord station and with slot widths of 0.63 and 0.094-in. These data were correlated to indicate the effects of slot location and slot width on minimum loss incidence and deviation angles. In addition, a comparison is presented of the performance parameters for cascades of slotted and unslotted hydrofoils.
Columbo, R. M.↗
Conjugate gradient determination of optimal plane changes for a class of three-impulse transfers between noncoplanar circular orbits
A particular type of three-impulse transfer between two circular orbits is analyzed. The possibility of three plane changes is recognized, and the problem is to optimally distribute these plane changes to minimize the sum of the individual impulses. Numerical difficulties and their solution are discussed. Numerical results obtained from a conjugate gradient technique are presented for both the case where the individual plane changes are unconstrained and for the case where they are constrained. Possibly not unexpectedly, multiple minima are found. The techniques presented could be extended to the finite burn case, but primarily the contents are addressed to preliminary mission design and vehicle sizing.
Burrows, R. R.↗
Shuttle on-orbit rendezvous targeting: Circular orbits
The strategy and logic used in a space shuttle on-orbit rendezvous targeting program are described. The program generates ascent targeting conditions for boost to insertion into an intermediate parking orbit, and generates on-orbit targeting and timeline bases for each maneuver to effect rendezvous with a space station. Time of launch is determined so as to eliminate any plane change, and all work was performed for a near-circular space station orbit.
Bentley, E. L.↗
Fatigue crack growth from a circular hole with and without high prior loading
Fatigue crack growth from a circular hole was investigated experimentally and analytically. An aluminum-alloy sheet specimen was cycled under a single level of loading with and without prior high loads. Tests showed that the crack propagation life was significantly longer when the high loads were applied initially. This longer life was attributed to compressive residual stresses produced near the hole by the initial high loads. The residual stresses near the hole were determined by an elastoplastic analysis and were then used to develop a stress-intensity solution for a crack growing through the residual stress field. This solution and a similar solution for the case of no prior loading were used to predict crack growth. The predicted crack growth agreed closely with the experimental values.
Crews, J. H., Jr.↗
Stress concentration in a cylindrical shell containing a circular hole.
The state of stress in a cylindrical shell containing a circular cutout was determined for axial tension, torsion, and internal pressure loading. The solution was obtained for the shallow shell equations by a variational method. The results were expressed in terms of a nondimensional curvature parameter which was a function of shell radius, shell thickness, and hole radius. The function chosen for the solution was such that when the radius of the cylindrical shell approaches infinity, the flat-plate solution was obtained. The results are compared with solutions obtained by more rigorous analytical methods, and with some experimental results. For small values of the curvature parameter, the agreement is good. For higher values of the curvature parameter, the present solutions indicate a limiting value of stress concentration, which is in contrast to previous results.
Adams, N. J. I.↗
Finite stretching of a circular plate of neo-Hookean material.
The analytical solution presented is based on the assumption that the deformed thickness of the plate is approximately constant. The nonlinear equations governing finite axisymmetric deformations of a circular plate made of neo-Hookean material are used in the analysis. The variation of circumferential extension ratio and the variation of deformed thickness are shown in graphs.
Biricikoglu, V.↗
The spectral dependence of circular polarization in Grw + 70 deg 8247.
Observation of sharp changes in circular polarization with wavelength in new observations of Grw + 70 deg 8247 made with 80 A resolution. Some of the structure is associated with the Minkowski bands. Continued broadband measurements show that while the polarization below 6000 A appears to remain constant, above this wavelength there have been significant changes in the past year.
Angel, J. R. P.↗
Modes of vibration in a circular plate with three simple support points.
The analytical solutions for the vibrational modes of a thin circular flat plate that is simply supported at three points on the circumference are presented. The mode shapes and corresponding eigenvalues are obtained. Results show that the modes can be grouped into four different types depending on the manner by which they receive the pressure at the supported points. The problem is of the mixed boundary value type in that some portion of the boundary is free while the other portion is simply supported.
Chi, C.↗
Free in-plane vibration of circular arches.
Numerical data are presented for the natural frequencies and modes of vibration of hinged and fixed, uniform, circular arches vibrating in their own plane, and the effects of the various parameters affecting the response are analyzed. It is shown that the vibrational modes may be almost purely flexural, or almost purely extensional, or the extensional and flexural actions may be strongly coupled. The conditions of occurrence of each type of behavior are defined, and simple approximate formulas are derived; using these formulas, the free vibrational characteristics of arches may be estimated to a satisfactory degree of accuracy for most practical applications. The approach used to derive the approximate formulas may also be applied to arches having other boundary conditions, shapes, or distributions of stiffness and mass.
Veletsos, A. S.↗
NGC 1068, 3C 273, and Scorpius X-1 - Circular polarization disputed.
Discussion of data for the Seyfert galaxy NGC 1068, the quasar 3C 273, and the X-ray source Sco X-1, for all of which it has been claimed or strongly suggested that they have large circular polarization of the order of 1% (Severny et al., 1971). In contrast the present authors obtained unambiguously null results with upper limits about 0.05% for NGC 1068 and 3C 273. For Sco X-1 no statistically significant polarization was found on three nights, and only some marginal evidence for a fluctuation or transient polarization on one night.
Kemp, J. C.↗
New measurements of circular polarization and an ephemeris for the variable white dwarf G195-19.
Observations of the white dwarf G195-19 made for over a year show that the periodic variation in circular polarization continues with constant frequency and amplitude; an accurate value of 1.3309 plus or minus 0.0004 days is obtained for the period. While the variation in blue-green light is sinusoidal, extensive measurements in red light show an asymmetric curve, reaching a minimum about 6 hours earlier than in the blue-green.
Angel, J. R. P.↗