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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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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Aerodynamic mathematical modeling - basic concepts

This lecture is a review of the basic concepts involved In the mathematical modeling of the aerodynamic response of an aircraft to arbitrary maneuvers. The review leads from Bryan's original formulation through the concepts of linear aerodynamic indicial functions and superposition to the extension of these concepts into the nonlinear regime. The nonlinear generalization yields a form for the aerodynamic response that can be built up from the responses to a limited number of well-defined characteristic motions, reproducible in principle either in wind-tunnel experiments or flow-field computations. A further generalization leads to a torn, accommodating the discontinuous and double-valued behavior characteristic of hysteresis in the steady-state aerodynamic response

Murray Tobak↗
NASA NTRS1981

Basic advances in the finite-volume method for transonic potential flow calculations

The finite-volume method of Jameson and Caughey provides a framework within which it is possible to calculate transonic potential flows about essentially arbitrary geometrical configurations. Improvements designed to increase the accuracy of the basic scheme and its consistency in the far field will be described. These include the incorporation of an artificial viscosity which maintains the formal second-order accuracy of the scheme in supersonic zones, and a modification of the flux balances to allow the free-stream conditions to satisfy the difference equations identically. Results of calculations illustrating the importance of these effects will be presented.

Caughey, D. A.↗
NASA NTRS1981

Spherical models: Basic states and stability

Steady axisymmetric basic states in a spherical cap and their stability to azimuthally varying perturbations of different wave numbers were numerically investigated. The main features of the planned computer code and numerical methods are outlined.

Roberts, G. O.↗
NASA NTRS1981

Reactivity of pyrylium salts toward basic reactants

The reactivity of some N-acyl and N-sulfonyl-hydrazines 2-4, 10a-10g, 12, 13, 16a, 16b and of hydrazones 18, benzyldihydrazone 21 towards pyrylium salts 1 was examined. By reaction of 2,4,6-trimethyl-pyrylium salt 1 with substituted hydrazines some pyridinium salts were obtained. Relationships between basicity and reactivity were discussed.

Neidlein, R.↗
NASA NTRS1982

Boundary-layer effects in composite laminates. I - Free-edge stress singularities. II - Free-edge stress solutions and basic characteristics

The fundamental nature of the boundary-layer effect in fiber-reinforced composite laminates is formulated in terms of the theory of anisotropic elasticity. The basic structure of the boundary-layer field solution is obtained by using Lekhnitskii's stress potentials (1963). The boundary-layer stress field is found to be singular at composite laminate edges, and the exact order or strength of the boundary layer stress singularity is determined using an eigenfunction expansion method. A complete solution to the boundary-layer problem is then derived, and the convergence and accuracy of the solution are analyzed, comparing results with existing approximate numerical solutions. The solution method is demonstrated for a symmetric graphite-epoxy composite.

Wang, S. S.↗
NASA NTRS1984

Dye Indicators for Acidic or Basic Surface Contamination

Application of pH-sensitive dye solution serves as test for acidic or basic contamination of critical bonding surface. Aqueous solution of 0.1 percent Direct Red No. 28 capable of indicating acid activating solution down to 10 parts per million on hardware and tooling. Dye did not cause detectable contamination of surface.

Lakin, A.↗
NASA NTRS1982

The LANDSAT Tutorial Workbook: Basics of Satellite Remote Sensing

Most of the subject matter of a full training course in applying remote sensing is presented in a self-teaching mode in this how-to manual which combines a review of basics, a survey of systems, and a treatment of the principles and mechanics of image analysis by computers, with a laboratory approach for learning to utilize the data through practical experiences. All relevant image products are included.

Short, Nicholas M.↗
NASA NTRS1983

BASIC Data Manipulation And Display System (BDMADS)

BDMADS, a BASIC Data Manipulation and Display System, is a collection of software programs that run on an Apple II Plus personal computer. BDMADS provides a user-friendly environment for the engineer in which to perform scientific data processing. The computer programs and their use are described. Jet engine performance calculations are used to illustrate the use of BDMADS. Source listings of the BDMADS programs are provided and should permit users to customize the programs for their particular applications.

Szuch, J. R.↗
NASA NTRS1983

Basic JCL for the CRAY-1 operating system (COS) with emphasis on making the transition from CDC 7600/SCOPE

Users of the CDC 7600 at Ames are assisted in making the transition to the CRAY-1. Similarities and differences in the basic JCL are summarized, and a dozen or so examples of typical batch jobs for the two systems are shown in parallel. Some changes to look for in FORTRAN programs and in the use of UPDATE are also indicated. No attempt is made to cover magnetic tape handling. The material here should not be considered a substitute for reading the more conventional manuals or the User's Guide for the Advanced Computational Facility, available from the Computer Information Center.

Howe, G.↗
NASA NTRS1982

The baroclinic instability of highly structured one-dimensional basic states

A frictionless, adiabatic, quasi-geostrophic model on a beta-plane was employed to examine the baroclinic instability of highly structured one-dimensional basic states. Definitions of the model eigenvalue equation, the boundary conditions, and the fluxes and energetics are provided, and highly structured average wind speed and temperature profiles were selected to represent a wide range of latitudes. Attention was given to the instability source, wavelength, growth rate, phase velocity, steering levels, and the vertical structure of their amplitude, phase, meridional entropy transport, and conversion of potential-to-kinetic energy. Green modes, Charney-Eady modes, and the modes defined in the paper are examined in connection with the highly structured profiles. The eigenvalue approach is shown to be superior to the numerical time integration approach and necessary conditions for instabilities are defined.

Fullmer, J. W. A.↗
NASA NTRS1983

Basic facts about Venus

Because of the disturbing influence of the earth's atmosphere on terrestrial and airborne telescopy, radiometry, thermal mapping, spectroscopy, polarimetry and radar astronomy of Venus, major improvements in the body of theory concerning that planet, began with the Mariner 2 planetary exploration program in 1962. The effect of spacecraft exploration culminated with the influx of data yielded by the Pioneer Venus and Venera 11 and 12 missions of 1978. Attention is presently given to the quantitative enhancement of widely accepted, basic facts about Venus that has resulted from the analysis of space probe data, together with an overview of the major features of past and planned planetary missions.

Colin, L.↗
NASA NTRS1983

The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics

In this review attention is called to basic phenomena and physical processes involved in the expansion of a plasma into a vacuum, or the expansion of a plasma into a more tenuous plasma, in particular the fact that upon the expansion, ions are accelerated and reach energies well above their thermal energy. Also, in the process of the expansion a rarefaction wave propagates into the ambient plasma, an ion front moves into the expansion volume, and discontinuities in plasma parameters occur. The physical processes which cause the above phenomena are discussed, and their possible application is suggested for the case of the distribution of ions and electrons (hence plasma potential and electric fields) in the wake region behind artificial and natural obstacles moving supersonically in a rarefied space plasma. To illustrate this, some in situ results are reexamined. Directions for future work in this area via the utilization of the Space Shuttle and laboratory work are also mentioned.

Wright, K. H., Jr.↗
NASA NTRS1983

Basic research for the geodynamics program

Laser systems deployed in satellite tracking were upgraded to accuracy levels where biases from systematic unmodelled effects constitute the basic factor that prohibits extraction of the full amount of information contained in the observations. Taking into consideration that the quality of the instrument advances at a faster pace compared to the understanding and modeling of the physical processes involved, one can foresee that in the near future when all lasers are replaced with third generation ones the limiting factor for the estimated accuracies will be the aforementioned biases. Therefore, for the reduction of the observations, methods should be deployed in such a way that the effect of the biases will be kept well below the noise level. Such a method was proposed and studied. This method consists of using the observed part of the satellite pass and converting the laser ranges into range differences in hopes that they will be less affected by biases in the orbital models, the reference system, and the observations themselves.

Source record↗
NASA NTRS1984

BRESEX: On board supervision, basic architecture and preliminary aspects for payload and space shuttle interface

Data relative to the on board supervision subsystem are presented which were considered in a conference between INPE and NASA personnel, with the purpose of initiating a joint effort leading to the implementation of the Brazilian remote sensing experiment - (BRESEX). The BRESEX should consist, basically, of a multispectral camera for Earth observation, to be tested in a future space shuttle flight.

Bergamini, E. W.↗
NASA NTRS1983

A basic design fault in ceramic flat packs

Recent moisture resistance tests of various multilayer top brazed ceramic flat packs and leaded and unleaded chip carriers has revealed a serious design defect. These packages, which utilize a tungsten interconnect system, in the presence of high humidity, suffer a galvanic corrosion which anodically consumes the tungsten. This process can continue until the package suffers an open circuit. The test results indicate that the lead plating system does not adequately seal off the interface area where the tungsten stripe egresses from the inside of the package. Leaded and leadless chip carrier packages were also subjected to the moisture resistance test. The familiar red and green corrosion products were visible after the test was completed. Careful sectioning of the chip carriers has revealed that the tungsten interconnect stripe instead of exiting under the castellations, exits at the top of the castellation and is thus vulnerable to the attack of moisture. These basic design faults severely impact the reliability of these packages.

Drotman, B.↗
NASA NTRS1984

Basic governing equations for the flight regimes of aeroassisted orbital transfer vehicles

The basic governing equations for the low-density, high-enthalpy flow regimes expected in the shock layers over the heat shields of the proposed aeroassisted orbital transfer vehicles are derived by combining and extending existing theories. The conservation equations are derived from gas kinetic principles for a four-component ionized gas consisting of neutral molecules, neutral atoms, singly ionized ions, and electrons, assuming a continuum flow. The differences among translational-rotational, vibrational, and electron temperatures are accounted for, as well as chemical nonequilibrium and electric-charge separation. Expressions for convective and viscous fluxes, transport properties, and the terms representing interactions among various energy modes are given explicitly. The expressions for the rate of electron-vibration energy transfer, which violates the Landau-Teller conditions, is derived by solving the system of master equations accounting for the multiple-level transitions.

Lee, J.-H.↗
NASA NTRS1984

Tropical response to lateral forcing with a latitudinally and zonally nonuniform basic state

The dynamics of lateral forcing of a stable tropical atmosphere by incident waves from the midlatitudes are examined. Attention is focused on conditions where the WKB method is invalid, and only given to barotropic flows. The tropical atmosphere is treated as a steady planetary wave and a zonal shear flow. The 200 mb level is investigated in terms of a midlatitude wave with self-compatible parametric values that is constrained to satisfy the radiation conditions at the boundary. Wave modes are found to be susceptible to trapping between two turning points in the equatorial zone in the presence of a zonal shear flow. Quasi-resonant waves can then appear over a wide range of parametric conditions of the forcing wave and the basic state. The zonal wind structure determines the resonance conditions.

Wilson, J. D.↗
NASA NTRS1984

Integrated analysis of remote sensing products from basic geological surveys

Recent advances in remote sensing led to the development of several techniques to obtain image information. These techniques as effective tools in geological maping are analyzed. A strategy for optimizing the images in basic geological surveying is presented. It embraces as integrated analysis of spatial, spectral, and temporal data through photoptic (color additive viewer) and computer processing at different scales, allowing large areas survey in a fast, precise, and low cost manner.

Dasilvafagundesfilho, E.↗