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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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The role which might be played by the space shuttle in obtaining data which describes the air quality of the north-eastern United States was investigated. The data requirements of users, a model for statistical interpretation of the observations, the influence of orbit parameters on the spatial and temporal sampling and an example of application of the the model were considered.
Several maximum likelihood and multiple regression parameter estimation programs are currently being used at the Langley Research Center of the NASA to analyze aircraft flight test data. Based on this wealth of experience, the pertinent features of these programs are investigated and some of the difficulties involved in their use are discussed. By comparing computational time, data requirements and accuracy needed, a strategy for determining which program can be used to the best advantage of the flight test engineer is discussed.
It is pointed out that the effective cooling of aircraft reciprocating engines is still a problem area for the general aviation industry. Miley et al. (1981) have reported the results of an investigation of problems associated with cooling and installation aerodynamics. A description is given of a flight test procedure which was developed in connection with the considered investigation. It is shown that the test procedure provides valid cooling requirements data for a particular installation. The data are in terms of easily measurable parameters. The employment of the test procedure, which is based on the NACA cooling correlation method, can lead to more effective cooling installations and the solution of existing cooling problems.
The groundwork for the use of advanced optical measurement techniques in Space Shuttle materials processing in space (MPS) experiments is being laid in tests, conducted aboard a NASA KC-135 aircraft flying a parabolic trajectory, involving a Mach-Zehnder interferometer and a sideband holographic unit. The two experiments described are (1) the observation of flow during solidification, in which fluid concentration and temperature profiles were measured during unidirectional solidification of a saturated NH4Cl-H2O solution, and (2) the observation of electrodeposition flow, in which interferometry is used to provide quantitative data required in the understanding of electrochemical process transport properties. The free-floating holographic unit was operated in the microgravity environment to both test the practicality of optical systems in such conditions and test the shock and vibration characteristics of the package.
A procedure for the evaluation of wall interference corrections for three-dimensional aircraft configurations is presented. The Mach number and angle-of-attack corrections are obtained by numerically solving the Laplace equation in a parallelepiped with boundary conditions supplied mainly from experimental pressure measurements. A portion of these measurements and other wind-tunnel data required by the procedure may be replaced by theoretical estimates if not available from experiments. The accuracy of the correction results will then depend on the accuracy of these estimates. The correction procedure is applied to an isolated wing and to a wing-tail configuration in a solid-wall wind tunnel. It is found that neglecting twist and camber corrections for the wing effectively increases the tail angle-of-attack correction. Two different Mach number corrections can be calculated for the wing and tail. However, since only one Mach number correction is allowed for both the wing and the tail, and since the wing surface area is larger than the tail surface area, the final correction tends to be closer to the required wing correction. This is a source of error for the tail results.
A four cylinder Stirling engine, transient engine simulation computer program is presented. The program is intended for controls analysis. The associated engine model was simplified to shorten computer calculation time. The model includes engine mechanical drive dynamics and vehicle load effects. The computer program also includes subroutines that allow: (1) acceleration of the engine by addition of hydrogen to the system, and (2) braking of the engine by short circuiting of the working spaces. Subroutines to calculate degraded engine performance (e.g., due to piston ring and piston rod leakage) are provided. Input data required to run the program are described and flow charts are provided. The program is modular to allow easy modification of individual routines. Examples of steady state and transient results are presented.
Data requirements, tasks to be accomplished, and the technical approaches to be used in identifying the characteristics of rice for crop inventories are listed as well as methods for estimating crop development and assessing its conditions.
Verification of the regional wind energy resource assessments produced by the Pacific Northwest Laboratory addresses the question: Is the magnitude of the resource given in the assessments truly representative of the area of interest? Approaches using qualitative indicators of wind speed (tree deformation, eolian features), old and new data of opportunity not at sites specifically chosen for their exposure to the wind, and data by design from locations specifically selected to be good wind sites are described. Data requirements and evaluation procedures for verifying the resource are discussed.
Tasks remaining to be completed are summarized for the following major project elements: (1) evaluation of crop yield models; (2) crop yield model research and development; (3) data acquisition processing, and storage; (4) related yield research: defining spectral and/or remote sensing data requirements; developing input for driving and testing crop growth/yield models; real time testing of wheat plant process models) and (5) project management and support.
A manual to provide a means by which a user may apply the snowmelt runoff model (SRM) unaided is presented. Model structure, conditions of application, and data requirements, including remote sensing, are described. Guidance is given for determining various model variables and parameters. Possible sources of error are discussed and conversion of snowmelt runoff model (SRM) from the simulation mode to the operational forecasting mode is explained. A computer program is presented for running SRM is easily adaptable to most systems used by water resources agencies.
The use of multidimensional optimization methods in solving power plant siting problems, which are characterized by several conflicting, noncommensurable objectives is addressed. After a discussion of data requirements and exclusionary site screening methods for bounding the decision space, classes of multiobjective and goal programming models are discussed in the context of finite site selection. Advantages and limitations of these approaches are highlighted and the linkage of multidimensional methods with the subjective, behavioral components of the power plant siting process is emphasized.
An overview of an analytic procedure which can be used to provide comprehensive stress and strength analysis of composite structures with stress concentrations is given. The methodology provides designer/analysts with a user-oriented procedure which, within acceptable engineering accuracy, accounts for the effects of a wide range of application design variables. The procedure permits the strength of arbitrary laminate constructions under general bearing/bypass load conditions to be predicted with only unnotched unidirectional strength and stiffness input data required. Included is a brief discussion of the relevancy of this analysis to the design of primary aircraft structure; an overview of the analytic procedure with theory/test correlations; and an example of the use and interaction of this strength analysis relative to the design of high-load transfer bolted composite joints.
In general, the data required for the more abundant species are: (1) linewidths as a function of temperature; (2) line strength measurements obtained at various temperatures when since quantum assignments for the lines are unknown the lower state energy levels are unknown; and (3) line strength measurements of the 'hot' bands and bands of the isotopic species. It is pointed out that an extensive list of line center frequencies and line strengths from 2400 to 3200 per cm of (CH4)4 has recently been added to the Air Force Geophysics Laboratory compilation. Since many of the lines in the list could not be assigned, the laboratory research required measurements of samples at various temperatures in order to experimentally determine the temperature dependence on the line strengths. The 'hot' band here refers to transitions arising from vibrational states other than the ground state. 'Hot' bands are usually near the parent band (arising from the ground state). Very few 'hot' bands are without parent bands.
The recent gamma ray and neutron observations made by the SMM Gamma Ray Spectrometer are reviewed. The implication these observations hold for understanding particle acceleration in solar flares are discussed. The data require that both electrons and ions must be accelerated together to relativistic energies and interact with matter in a time scale of seconds.
Carrier plate assemblies of NASA Space Shuttle thermal protection system provided for easy access to protected vital parts of Shuttle. Each assembly mounted on substructure with fasteners through holes in protective tiles. Automatic System of Kinematic Analysis (ASKA) finite-element program evaluates these assemblies. PLATEFORT computer program developed as data generator for ASKA modeling. PLATEFORT greatly reduces amount of time and data required for building ASKA model of these assemblies.
The first five flights of the orbiter Columbia provided the initial data required to certify the operational performance of the reusable surface insulation (RSI) thermal protection system (TPS). The flight performance characteristics of the RIS TPS are discussed. The discussion is based primarily on postflight inspections and postflight interpretation of the flight instrumentation. TPS modifications of the future orbiters (OV-099, 103, and subs) are also discussed.
A simple model describing the discharge chamber performance of high strength, cusped magnetic field ion thrusters is developed. The model is formulated in terms of the energy cost of producing ions in the discharge chamber and the fraction of ions produced in the discharge chamber that are extracted to form the ion beam. The accuracy of the model is verified experimentally in a series of tests wherein the discharge voltage, propellant, grid transparency to neutral atoms, beam diameter and discharge chamber wall temperature are varied. The model is exercised to demonstrate what variations in performance might be expected by varying discharge chamber parameters. The results of a study of xenon and argon orificed hollow cathodes are reported. These results suggest that a hollow cathode model developed from research conducted on mercury cathodes can also be applied to xenon and argon. Primary electron mean free paths observed in argon and xenon cathodes that are larger than those found in mercury cathodes are identified as a cause of performance differences between mercury and inert gas cathodes. Data required as inputs to the inert gas cathode model are presented so it can be used as an aid in cathode design.
The Planet-Crossing Asteroid Survey (PCAS) is making steady progress toward the accumulation of the data required to make improved estimates of the populations and cratering rates which can be compared with the existing record of impact events. The PCAS is the chief source of new objects on which to base these calculations over the past decade, and is an integral part of the continuing refinement of the estimates used in planetological applications. An adjunct effort to determine albedo statistics from photometry of UCAS plates is being pursued as well, to better define the magnitude frequency distributions of asteroids. This will improve the quality of the population and collision probability calculations. The survey effort continues to discover new asteroids whose orbital characteristics may reveal the origin and evolution mechanisms reponsible for the transport of the planet-crossing asteroids to the inner solar system.