Astrophysical evidence for the direct electron- neutrino weak interaction.
Plasma neutrino process of Adams, Ruderman and Woo dependent on direct electron-neutrino interaction and connected with stellar evolution
Chin, C.-W.↗
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Some numerical methods for integrating systems of first-order ordinary differential equations
Report on numerical methods of integration includes the extrapolation methods of Bulirsch-Stoer and Neville. A comparison is made nith the Runge-Kutta and Adams-Moulton methods, and circumstances are discussed under which the extrapolation method may be preferred.
Clark, N. W.↗
Interferometric studies of interstellar calcium lines.
Review of interferometric, photoelectric scans of the interstellar calcium K-lines in the spectra of 65 stars. The scans were obtained with a PEPSIOS spectrometer having a passband with a full half-intensity width of 1.0 km/sec or 0.013 A. The fivefold improvement in resolution over that used by Adams reveals numerous line components which correspond very well to those of the interstellar sodium lines, apart from frequent differences in relative intensities.
Marschall, L. A.↗
Calculation of stability derivatives for slowly oscillating bodies of revolution at Mach 1.0
A parabolic method for steady transonic flow is extended to bodies of revolution oscillating in a sonic flow field. A Laplace transform technique is employed to derive the dipole solution, and the Adams-Sears iterative technique is used in the stability derivative calculation. A computer program is developed to perform the stability derivative calculation for the slowly oscillating cone and parabolic ogive. Inputs for the program are body geometry thickness ratio, acceleration constant, and pitch axis location. Sample calculations were performed for the parabolic ogive and circular cone and results are compared with those obtained by using other techniques and the available experimental data for circular cones.
Ruo, S. Y.↗
Numerical integration routines for near-earth operations
Two general purpose numerical integration schemes were built into the NASA-JSC computer system. The state-of-the-art of numerical integration, the particular integrators built into the JSC computer system, and the use of the new integration packages are described. Background information about numerical integration and the variable-order, variable-stepsize Adams numerical integration technique is discussed. Results concerning the PEACE parameter optimization program are given along with recommendations and conclusions.
Powers, W. F.↗
Unsteady transonic flow analysis for low aspect ratio, pointed wings.
Oswatitsch and Keune's parabolic method for steady transonic flow is applied and extended to thin slender wings oscillating in the sonic flow field. The parabolic constant for the wing was determined from the equivalent body of revolution. Laplace transform methods were used to derive the asymptotic equations for pressure coefficient, and the Adams-Sears iterative procedure was employed to solve the equations. A computer program was developed to find the pressure distributions, generalized force coefficients, and stability derivatives for delta, convex, and concave wing planforms.
Kimble, K. R.↗
Interferometric studies of interstellar CH/+/ molecules.
The work reported consists of interferometric, photoelectric scans in the region of the line at 4232 A in the spectra of 28 stars. An instrumental passband of about 0.014 A was selected for the observations. In comparison with the capabilities of the older methods utilized in particular by Adams, the present method yields a fivefold improvement in spectral resolution, as well as the higher accuracy inherent in photoelectric detection. As a result, the detailed line profiles of individual line components can be recorded rather than only the composite equivalent widths.
Hobbs, L. M.↗
Thermal surveillance of volcanoes of the Cascade Range utilizing ERTS DCP systems and imagery
The author has identified the following significant results. Successful installation of DCP sets at Mt. Baker volcano and at Mt. St. Helens volcano, Washington, completed the installation phase of experiment SR 251. Aerial IR scanner missions over the Cascade volcanoes were completed with a mission April 29th which provided thermographic IR images of Glacier Peak, Mt. Baker, Mt. St. Helens, Mt. Rainier, and Mt. Adams. Earlier repetitive coverage had obtained IR images depicting thermal anomalies of Lassen Volcanic National Park, Shasta, Crater Lake, and the northern Cascades. The April 29th mission and subsequent ground reconnaissance yielded new information on 48 heretofore unreported pinpoint radiation anomalies, of possible fumarolic origin, on the flanks of Mt. Rainier and several new thermal points on Mt. Baker. Cartographic plots of these anomalies, in conjunction with surface temperature and other data obtained as a result of experiment SR 251 will permit estimation of radiation heat loss during the repose periods of the host volcanoes.
Friedman, J. D.↗
Assess program: Interactive data management systems for airborne research
Two data systems were developed for use in airborne research. Both have distributed intelligence and are programmed for interactive support among computers and with human operators. The C-141 system (ADAMS) performs flight planning and telescope control functions in addition to its primary role of data acquisition; the CV-990 system (ADDAS) performs data management functions in support of many research experiments operating concurrently. Each system is arranged for maximum reliability in the first priority function, precision data acquisition.
Munoz, R. M.↗
On testing a subroutine for the numerical integration of ordinary differential equations
This paper discusses how to numerically test a subroutine for the solution of ordinary differential equations. Results obtained with a variable order Adams method are given for eleven simple test cases.-
Krogh, F. T.↗
Elastoplastic transverse properties of a unidirectional fibre reinforced composite
An approximate theoretical study is made to predict the overall transverse elastoplastic properties of a unidirectional fibre reinforced composite. Based on the simplest deformation theory of plasticity, the overall transverse polyaxial elastoplastic constitutive equations for an incompressible composite are obtained. A simple formula is suggested to evaluate the average stress in the fibres. Furthermore, with the prediction of the overall transverse elastic moduli of a compressible composite, the overall transverse uniaxial stress-strain curve for a compressible composite in the entire elastic-plastic range is obtained. A detailed example is given for a Boron-Aluminum composite. Comparison is made with the experimental and theoretical work done by General Dynamics and Adams respectively.
Huang, W.-C.↗
Feedback precision and postfeedback interval duration
Precision of feedback gain was manipulated in a simple positioning task. An optimum was found; an increase in precision past that optimum produced deleterious effects upon rate of acquisition. In a second study, increasing postfeedback interval removed that optimum. The feedback precision effects were then replicated in a timing task. The combined results of the 3 studies were interpreted as supportive of an information-processing approach to the study of postfeedback interval events for simple motor skills. The findings additionally supported specific predictions by Bilodeau and deductions from Adams' 1971 theory of motor learning.
Rogers, C. A., Jr.↗
Multi-off-grid methods in multi-step integration of ordinary differential equations
Description of methods of solving first- and second-order systems of differential equations in which all derivatives are evaluated at off-grid locations in order to circumvent the Dahlquist stability limitation on the order of on-grid methods. The proposed multi-off-grid methods require off-grid state predictors for the evaluation of the n derivatives at each step. Progressing forward in time, the off-grid states are predicted using a linear combination of back on-grid state values and off-grid derivative evaluations. A comparison is made between the proposed multi-off-grid methods and the corresponding Adams and Cowell on-grid integration techniques in integrating systems of ordinary differential equations, showing a significant reduction in the error at larger step sizes in the case of the multi-off-grid integrator.
Beaudet, P. R.↗
Comparison of numerical integration techniques for orbital applications
The present work gives a brief comparison of the performance of programs for integrating differential equations for orbital applications. The evaluation criteria and the method of testing are described, and the results of the test problem set are included. Integration methods that were chosen for comparison include high-order Runge-Kutta methods; a rational extrapolation method (Bulirsch and Stoer, 1966); a variable step, variable order, multistep method (Krogh, 1969); classical multistep methods of Adams and Cowell; and modified multistep methods. The high-order Runge-Kutta methods used in the comparison include RKF 7(8) and RKF 8(9) (Fehlberg, 1968), and RKS 8-10 (Shanks, 1966).
Moore, H.↗
On the velocity dependence of the interstellar Na I/Ca II ratio
The correlation noted by Routly and Spitzer (1952) between the ratio of the column densities of interstellar Na I and Ca II and radial velocity in the spectra of 21 early-type stars is reinvestigated on the basis of more recent data for 64 stars. The original result is confirmed, and it is further demonstrated that the low values of Na I/Ca II are associated with large peculiar velocities relative to the local standard of rest. It is proposed that the bulk of the high-velocity components can be interpreted as old supernova remnants. A statistical analysis of the distribution with velocity of interstellar Ca II K lines observed by Adams (1949) in the directions of some 300 early-type stars is found to be consistent with this hypothesis.
Siluk, R. S.↗
Numerical orbit integration efficiency of the Delaunay-Similar elements
Orbit equations with a set of conservative and a set of nonconservative perturbing potentials were considered. Scheifele's DS formulation of these equations has dependent variables similar to Delaunay's orbital elements with the true anomaly as the independent variable. Efficiency curves of computing cost v.s. accuracy were constructed for Adams integrators of order of 2 through 15 with several correcting algorithms and for a Runga-Kutta integrator. Considering stability regions, choices were made for the optimally efficient integration modes for the DS elements. Integrating in these modes reduces computing costs for a specified accuracy.
Pierce, S.↗
Three-dimensional time dependent computation of turbulent flow
The three-dimensional, primitive equations of motion are solved numerically for the case of isotropic box turbulence and the distortion of homogeneous turbulence by irrotational plane strain at large Reynolds numbers. A Gaussian filter is applied to governing equations to define the large scale field. This gives rise to additional second order computed scale stresses (Leonard stresses). The residual stresses are simulated through an eddy viscosity. Uniform grids are used, with a fourth order differencing scheme in space and a second order Adams-Bashforth predictor for explicit time stepping. The results are compared to the experiments and statistical information extracted from the computer generated data.
Kwak, D.↗
On testing a subroutine for the numerical integration of ordinary differential equations
This paper discusses how to numerically test a subroutine for the solution of ordinary differential equations. Results obtained with a variable order Adams method are given for eleven simple test cases.-
Krogh, F. T.↗