The theory of Cepheid variability.
Nonlinear methods application to Cepheid pulsation variables theory for determinations of mass, luminosity, radius and helium content
Christy, R. F.↗
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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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A passive method for scanning the celestial sphere.
Celestial sphere scanning by passive method applicable to space missions requiring long lifetime and moderate pointing accuracies
Fleig, A. J., Jr.↗
Monte Carlo calculations of a hemispherical duct neutron streaming experiment.
Monte Carlo method application to neutron streaming in hemispherical air-filled ducts in water tank to determine leakage through nuclear reactor shields
Clemons, L.↗
A passive method for scanning the celestial sphere.
Celestial sphere scanning by passive method applicable to space missions requiring long lifetime and moderate pointing accuracies
Fleig, A. J., Jr.↗
Finite-element solution of the incompressible lubrication problem.
Finite element method application to minimum principle for incompressible lubrication problem, noting flow boundary conditions and squeeze film effects
Reddi, M. M.↗
Application of calibration masks to TV vidicon tube
Photographic application method devised for overlaying test pattern masks on TV camera vidicon tubes prints the mask within 0.0076 cm of the vertical and horizontal center lines of the tube face. Entire process, including mask fabrication and alignment procedure, requires less than 10 minutes.
Brawner, E. L.↗
The doubling method applied to multiple scattering of polarized light
Doubling method application to multiple scattering of polarized light, studying Venus visible disk reflection of sunlight
Hansen, J. E.↗
Generalized relaxation methods applied to problems in transonic flow
Generalized relaxation methods application to transonic flow problems, combining with numerical integration theory for ordinary differential equations
Lomax, H.↗
An examination of applications of remote sensing data to Metropolitan Washington Council of Governments' planning requirements
A comprehensive inventory of a series of remote sensing applications for a variety of regional planning programs in metropolitan Washington was undertaken. Examples of application, methods for data utilization, and corresponding photographic illustrations are provided illustrating how remote sensing would prove particularly useful as a unique and/or supplemental data source.
Mallon, H. J.↗
Lightweight evacuated multilayer insulation systems for the space shuttle vehicle
The elements in the evacuated multilayer insulation system were investigated, and the major weight contributors for optimization selected. Outgassing tests were conducted on candidate vacuum jacket materials and experiments were conducted to determine the vacuum and structural integrity of selected vacuum jacket configurations. A nondestructive proof test method, applicable to externally pressurized shells, was validated on this program.
Barclay, D. L.↗
Development of high temperature silicone adhesive formulations for thermal protection system applications
Trade-off studies and screening evaluations were made of commercial polymers and silicone foam sheet stock. A low modulus, low density 0.26 gm/cc modification was developed of the GE-RESD PD-200 system based upon GE RTV-560 silicone polymer. The bond system modification was initially characterized for mechanical and thermal properties, evaluated for application methods, and its capability demonstrated as a strain arrestor bond system.
Hockridge, R. R.↗
A finite element tensor approach to plate buckling and postbuckling.
A practical finite element method is presented for geometrically nonlinear (von Karman) plate problems. Symmetric strain energy tensors provide an efficient formulation and solution, and allow the effects of initial imperfections to be considered. An unbalanced force iteration is employed, with the advantage that the time consuming Gauss decomposition needs to be performed only once. The convergence is controlled by an automatically computed relaxation factor, and this makes the method applicable in advanced stages of non-linearity. Several different triangular elements are used in explicitly deriving the required tensors.
Vos, R. G.↗
Sizing of complex structure by the integration of several different optimal design algorithms
Practical design of large-scale structures can be accomplished with the aid of the digital computer by bringing together in one computer program algorithms of nonlinear mathematical programing and optimality criteria with weight-strength and other so-called engineering methods. Applications of this approach to aviation structures are discussed with a detailed description of how the total problem of structural sizing can be broken down into subproblems for best utilization of each algorithm and for efficient organization of the program into iterative loops. Typical results are examined for a number of examples.
Sobieszczanski, J.↗
Prediction and verification of creep behavior in metallic materials and components, for the space shuttle thermal protection system. Volume 1, phase 1: Cyclic materials creep predictions
Cyclic creep response was investigated and design methods applicable to thermal protection system structures were developed. The steady-state (constant temperature and load) and cyclic creep response characteristics of four alloys were studied. Steady-state creep data were gathered through a literature survey to establish reference data bases. These data bases were used to develop empirical equations describing creep as a function of time, temperature, and stress and as a basis of comparison for test data. Steady-state creep tests and tensile cyclic tests were conducted. The following factors were investigated: material thickness and rolling direction; material cyclic creep response under varying loads and temperatures; constant stress and temperature cycles representing flight conditions; changing stresses present in a creeping beam as a result of stress redistribution; and complex stress and temperature profiles representative of space shuttle orbiter trajectories. A computer program was written, applying creep hardening theories and empirical equations for creep, to aid in analysis of test data. Results are considered applicable to a variety of structures which are cyclicly exposed to creep producing thermal environments.
Davis, J. W.↗
Chemico-therapeutic approach to prevention of dental caries
The program of chemical preventive dentistry is based primarily upon the development of a procedure for stabilizing stannous fluoride in solution by forcing it into glycerin. New topical fluoride treatment concentrates, fluoride containing gels and prophylaxis pastes, as well as a completely stable stannous fluoride dentifrice are made possible by the development of a rather complicated heat application method to force stannous fluoride into solution in glycerin. That the stannous fluoride is clinically effective in such a preparation is demonstrated briefly on orthodontic patients.
Shannon, I. L.↗
The remote-sensing program of the Geological Survey of Alabama
Some areas of remote-sensing research in Alabama are reviewed, showing how remote sensing technology can provide data that cannot be obtained by other methods. Applications of this technology to structural and stratigraphic research and to the search for water, mineral, and energy sources are discussed, and some results of these applications are illustrated.
Drahovzal, J. A.↗
The use of local basis functions in unsteady aerodynamics
This paper reports a successful demonstration of using local basis functions to solve Kussner's integral equation for unsteady airloads. Pressure basis functions are defined over relatively small subsets of the aerodynamic surface and are zero elsewhere. This formulation combines the accuracy and smoothness of distribution methods with the simplicity and versatility of panel methods. Application is made to subsonic compressible flow about oscillating planar surfaces with controls. Numerical results are presented. Convergence with respect to panel size, extensions to more general classes of solutions, and areas needing additional investigation are discussed.
Fromme, J.↗
Inverse atmospheric radiative transfer problems - A nonlinear minimization search method of solution
The paper studies the inversion of the radiative transfer equation describing the interaction of electromagnetic radiation with atmospheric aerosols. The interaction can be considered as the propagation in the aerosol medium of two light beams: the direct beam in the line-of-sight attenuated by absorption and scattering, and the diffuse beam arising from scattering into the viewing direction, which propagates more or less in random fashion. The latter beam has single scattering and multiple scattering contributions. In the former case and for single scattering, the problem is reducible to first-kind Fredholm equations, while for multiple scattering it is necessary to invert partial integrodifferential equations. A nonlinear minimization search method, applicable to the solution of both types of problems has been developed, and is applied here to the problem of monitoring aerosol pollution, namely the complex refractive index and size distribution of aerosol particles.
Fymat, A. L.↗