Quark Model of Leptons
Model in which leptons are deeply bound states of combinations of quarks and quirks
LEPTON↗
SEARCH · Search NASA
Results for “Mathematical Physics”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Geometric theory of functional-differential equations.
Functional differential equations geometric theory, with rate of change of physical system mathematical model dependent on past history
Hale, J. K.↗
Models for obtaining effects of ground winds on space vehicles erected on the launch pad
Physical and mathematical models for studying erected launch vehicle response to ground winds
Reed, W. H., III↗
Modeling the nonlinear behavior of arteries
Arterial wall nonlinear distensibility effects on blood flow velocity profiles, considering various mathematical and physical artery models
Ling, S. C.↗
Computer program draws three-dimensional surfaces
Computer plotting program PLOT 3D draws views of surface forms z = f(x,y). Surface thus defined by program may be drawn after arbitrary rotations. Program portrays behavior of various functions involving two variables in many engineering, physics, and mathematical relationships.
Canright, R. B., Jr.↗
Astrodynamics. Volume 1 - Orbit determination, space navigation, celestial mechanics.
Essential navigational, physical, and mathematical problems of space exploration are covered. The introductory chapters dealing with conic sections, orientation, and the integration of the two-body problem are followed by an introduction to orbit determination and design. Systems of units and constants, as well as ephemerides, representations, reference systems, and data are then dealt with. A detailed attention is given to rendezvous problems and to differential processes in observational orbit correction, and in rendezvous or guidance correction. Finally, the Laplacian methods for determining preliminary orbits, and the orbit methods of Lagrange, Gauss, and Gibbs are reviewed.
Herrick, S.↗
Subsonic, transonic, and supersonic nozzle flow by the inverse technique.
The inverse technique is used to obtain a mathematically and physically consistent solution of the flowfield in a nozzle from the mass generation surface through the supersonic region. The inverse method employs an assumed centerline function which is of the Cauchy type in that the values and the derivatives of the function are known. Since the Cauchy boundary conditions can give rise to numerical instabilities, the governing gasdynamic equations for rotational steady flow were transformed into a form which puts the geometry into a rectangular shape, and which spaces the network of interior points more finely in regions of the greatest gradients of the dependent variables. For arbitrarily specified centerline data, the solution of the governing flow equations may not exist, and if it does it may not depend continuously on the data.
Norton, D. J.↗
Comparison of some approximations for isotropic turbulence.
Study of several related turbulence approximations with regard to dynamical properties and agreement of numerical predictions with laboratory and computer experiments. The approximations considered include the direct-interaction equations (Kraichnan, 1964), Herring's (1966) self-consistent-field theory, a generalization of Edwards' (1964) theory, the abridged Lagrangian-history, direct-interaction approximation (Kraichnan, 1966), the test-field model (Kraichnan, 1971), and an approximation, not previously described, in which one velocity field passively suffers convection by another. Most of the cited approximations are representable by stochastic model equations for the velocity amplitude. Explicit constructions are given for the stochastic models, in a form that can be approximated on a digital computer. These constructions are used to discuss the physical and mathematical differences between the model dynamics and actual Navier-Stokes dynamics.-
Herring, J. R.↗
Design of the UCLA general circulation model
An edited version is reported of notes distributed at the Summer Workshop on the UCLA General Circulation Model in June 1971. It presents the computational schemes of the UCLA model, along with the mathematical and physical principles on which these schemes are based. Included are the finite difference schemes for the governing fluid-dynamical equations, designed to maintain the important integral constraints and dispersion characteristics of the motion. Also given are the principles of parameterization of cumulus convection by an ensemble of identical clouds. A model of the ground hydrology, involving the liquid, ice and snow states of water, is included. A short summary is given of the scheme for computing solar and infrared radiation transfers through clear and cloudy air.
Arakawa, A.↗
Image sharpening by holography.
Discussion of the physical and mathematical fundamentals, performance capabilities and potential applications of image deblurring by holography. It is shown that a blurred photograph may be deblurred and a sharpened image extracted from it because the 'blurring' in the original photograph did not irretrievably lose the imaging information, notably in the spatial-frequency regions required for faithful imaging and for high resolution. The principles of optical image deblurring are highly mathematical in nature. One of the most important applications of holographic image deblurring is shown to be the sharpening of electron micrographs of biological specimens beyond the ultimate that can be achieved with even the most powerful instruments available.
Stroke, G. W.↗
Investigation of earth's albedo using Skylab data
The author has identified the following significant results. Specific test sites in the White Sands, New Mexico and Lake Michigan areas were chosen because of their stability and known reflectances. Skylab S192 multispectral data and ERIM aircraft multispectral data were collected for these sites and were compared with results of atmospheric radiative transfer calculations in order to determine the aerosol content of the atmosphere. The spectral shape of the Skylab data compared quite favorably with the nearly simultaneous spectral character of the aircraft data. Although there were difficulties in the calibration of the S192 instrument which remain unresolved, interesting mathematical and physical relationships were discovered.
Turner, R. E.↗
On estimating gravity anomalies: A comparison of least squares collocation with least squares techniques
The least squares collocation algorithm for estimating gravity anomalies from geodetic data is shown to be an application of the well known regression equations which provide the mean and covariance of a random vector (gravity anomalies) given a realization of a correlated random vector (geodetic data). It is also shown that the collocation solution for gravity anomalies is equivalent to the conventional least-squares-Stokes' function solution when the conventional solution utilizes properly weighted zero a priori estimates. The mathematical and physical assumptions underlying the least squares collocation estimator are described, and its numerical properties are compared with the numerical properties of the conventional least squares estimator.
Argentiero, P.↗
A kinetic-theory approach to turbulent chemically reacting flows
The paper examines the mathematical and physical foundations for the kinetic theory of reactive turbulent flows, discussing the differences and relation between the kinetic and averaged equations, and comparing some solutions of the kinetic equations obtained by the Green's function method with those obtained by the approximate bimodal method. The kinetic method described consists essentially in constructing the probability density functions of the chemical species on the basis of solutions of the Langevin stochastic equation for the influence of eddies on the behavior of fluid elements. When the kinetic equations are solved for the structure of the diffusion flame established in a shear layer by the bimodal method, discontinuities in gradients of the mean concentrations at the two flame edges appear. This is a consequence of the bimodal approximation of all distribution functions by two dissimilar half-Maxwellian functions, which is a very crude approximation. These discontinuities do not appear when the solutions are constructed by the Green's function method described here.
Chung, P. M.↗
Response of linear dynamic systems with random coefficients
Numerous models of physical systems contain parameters whose values are not known exactly. The physical and mathematical complexities arising in the prediction of the statistical behavior of such systems are discussed. Although the discussions are far from providing a satisfactory solution to such problems, they perhaps, by utilization of simple examples, will create a greater awareness of the statistical effect of random parameters.
Dickerson, J.↗
Wave refraction diagrams for the Baltimore Canyon region of the mid-Atlantic continental shelf computed by using three bottom topography approximation techniques
The Langley Research Center and Virginia Institute of Marine Science wave refraction computer model was applied to the Baltimore Canyon region of the mid-Atlantic continental shelf. Wave refraction diagrams for a wide range of normally expected wave periods and directions were computed by using three bottom topography approximation techniques: quadratic least squares, cubic least squares, and constrained bicubic interpolation. Mathematical or physical interpretation of certain features appearing in the computed diagrams is discussed.
Poole, L. R.↗
Combustion of hydrogen injected into a supersonic airstream (the SHIP computer program)
The mathematical and physical basis of the SHIP computer program which embodies a finite-difference, implicit numerical procedure for the computation of hydrogen injected into a supersonic airstream at an angle ranging from normal to parallel to the airstream main flow direction is described. The physical hypotheses built into the program include: a two-equation turbulence model, and a chemical equilibrium model for the hydrogen-oxygen reaction. Typical results for equilibrium combustion are presented and exhibit qualitatively plausible behavior. The computer time required for a given case is approximately 1 minute on a CDC 7600 machine. A discussion of the assumption of parabolic flow in the injection region is given which suggests that improvement in calculation in this region could be obtained by use of the partially parabolic procedure of Pratap and Spalding. It is concluded that the technique described herein provides the basis for an efficient and reliable means for predicting the effects of hydrogen injection into supersonic airstreams and of its subsequent combustion.
Markatos, N. C.↗
What's the use of land? (a secondary school social studies project)
The concept of a student land use survey was discussed with the curriculum development team of the Jefferson County Public Schools in Colorado. In these discussions it soon became apparent that the curriculum potentials included much more than a classroom activity involving mapping the features on the ground in the area of study. A new flood control dam to be located in the area of Denver, Colorado, became the central topic in a program involving a wide variety of curriculum fields, such as mapmaking, local community history, physical geography, mathematics, and environmental studies. Consequently, a prototype of a multidisciplinary unit concept was developed for later incorporation by the Jefferson County curriculum team.
Source record↗
On estimating gravity anomalies - A comparison of least squares collocation with conventional least squares techniques
The least squares collocation algorithm for estimating gravity anomalies from geodetic data is shown to be an application of the well known regression equations which provide the mean and covariance of a random vector (gravity anomalies) given a realization of a correlated random vector (geodetic data). It is also shown that the collocation solution for gravity anomalies is equivalent to the conventional least-squares-Stokes' function solution when the conventional solution utilizes properly weighted zero a priori estimates. The mathematical and physical assumptions underlying the least squares collocation estimator are described.
Argentiero, P.↗