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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 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Development of a drift-correction procedure for a photoelectric spectrometer

A technique has been developed to automatically correct for drifts in the radiometric sensitivity of the detector channels in a direct-reading emission spectrometer. The method utilizes a 1000 W tungsten-halogen reference lamp to illuminate the detectors through the same optical path as that traversed during the analysis of the sample. Detector channel responses to the light are compared to those for the same light intensity at the time of analytical calibration. This corrects for the drift. It is noted that with the exception of positioning the lamp, the procedure is fully automatic.

Chapman, G. B., II↗
NASA NTRS1977

A solar energy estimation procedure using remote sensing techniques

The objective of this investigation is to design a remote sensing-aided procedure for daily location-specific estimation of solar radiation components over the watershed(s) of interest. This technique has been tested on the Spanish Creek Watershed, Northern California, with successful results.

Khorram, S.↗
NASA NTRS1978

Transonic lifting line theory - Numerical procedure for shock-free flows

An algorithm for computing transonic lifting-line theory without shocks is presented; the numerical procedure relies on two-dimensional analyses developed to solve inviscid flow equations for slender airfoils. From a series of solutions to two-dimensional problems in which span effects appear parametrically, the three-dimensional potential field characterization is obtained. Numerical results are given for a lifting wing with an elliptic (spanwise) distribution of chord and a NACA-0012 cross section (a freestream Mach number of 0.63 and an angle of attack of 2 deg are assumed).

Small, R. D.↗
NASA NTRS1978

U.S. terrestrial solar cell calibration and measurement procedures

An outline is presented of changes in measurement procedures concerning solar cells. Outdoor measurements of cell performance based on pyranometer or pyrheliometer determination of intensity are discouraged. The absolute scale of irradiance is to be adopted as soon as possible. The standard atmosphere conditions are 1000 W/sq m irradiance, temperature 28 C, air mass 1.5, and precipitable water vapor content of 2 cm. The allowable light sources for solar simulation are short arc xenon lamps, pulsed xenon lamps, and dichroic filtered tungsten lamps. Key considerations in the design of a reference cell are considered and approaches for the matching of a reference cell to a test cell or modules are discussed.

Brandhorst, H. W., Jr.↗
NASA NTRS1978

A direct element resequencing procedure

Element by element frontal solution algorithms are utilized in many of the existing finite element codes. The overall computational efficiency of this type of procedure is directly related to the element data input sequence. Thus, it is important to have a pre-processor which will resequence these data so as to reduce the element wavefronts to be encountered in the solution algorithm. A direct element resequencing algorithm is detailed for reducing element wavefronts. It also generates computational by products that can be utilized in pre-front calculations and in various post-processors. Sample problems are presented and compared with other algorithms.

Akin, J. E.↗
NASA NTRS1978

Test procedures

The test procedures required to evaluate the performance of the Space Lab Bus Interface Unit (SL/BIU) are described. This level of testing involves the design evaluation of signal levels, timing, and signal-to-noise (S/N) performance. The tests are to be comprehensive in order to provide data on the operational characteristics of the SL/BIU. The evluation tests are designed to accomplish the following determinations as a minimum for component level testing of the SL/BIU: (1) the baseline operation parameters for comparison to ICD 2-05301 requirements; (2) the influence of serial data line parameter variation on the operation of SL/BIU; (3) the effects of noise on discrete and serial data lines (S/N ratio); and (4) the effects of cable length variation.

Source record↗
NASA NTRS1978

Voyager electronic parts radiation program. Volume 2: Test requirements and procedures

Documents are presented outlining the conditions and requirements of the test program. The Appendixes are as follows: appendix A -- Electron Simulation Radiation Test Specification for Voyager Electronic Parts and Devices, appendix B -- Electronic Piece-Part Testing Program for Voyager, appendix C -- Test Procedure for Radiation Screening of Voyager Piece Parts, appendix D -- Boeing In Situ Test Fixture, and appendix E -- Irradiate - Anneal (IRAN) Screening Documents.

Stanley, A. G.↗
NASA NTRS1978

Radiometric correction procedure study

A comparison of MSS radiometric processing techniques identified as a preferred radiometric processing technique a procedure which equalizes the mean and standard deviation of detector-specific histograms of uncalibrated scene data. Evaluation of MSS calibration data demonstrated that the relationship between detector responses is essentially linear over the range of intensities typically observed in MSS data, and that the calibration wedge data possess a high degree of temporal stability. An analysis of the preferred radiometric processing technique showed that it could be incorporated into the MDP-MSS system without a major redesign of the system, and with minimal impact on system throughput.

Colby, C.↗
NASA NTRS1979

A procedure obtaining stiffnesses and masses of a structure from vibration modes and substructure static test data

A component mode desynthesis procedure is developed for determining the unknown vibration characteristics of a structural component (i.e., a launch vehicle) given the vibration characteristics of a structural system composed of that component combined with a known one (i.e., a payload). At least one component static test has to be performed. These data are used in conjunction with the system measured frequencies and mode shapes to obtain the vibration characteristics of each component. The flight dynamics of an empty launch vehicle can be determined from measurements made on a vehicle/payload combination in conjunction with a static test on the payload.

Edighoffer, H. H.↗
NASA NTRS1979

Statistical comparisons of aircraft flyover noise adjustment procedures for different weather conditions

Aircraft flyover noise spectra and effective perceived noise level (EPNL) values obtained under widely different weather conditions were adjusted according to a proposed national standard. The results were statistically compared with the same measured spectra adjusted according to an alternate procedure and with reference spectra and EPNL values obtained under almost ideal weather conditions. Three different ways to represent the weather condition through which the sound propagated were also evaluated.

Mueller, A. W.↗
NASA NTRS1978

An assessment of thermal design procedures for Shuttle payloads

A review of the thermal design options for unmanned Shuttle payloads is presented. Because many future Shuttle payloads will have budgets and less time available for the definition of their thermal subsystems, simplified design procedures will be the most cost-effective. The thermal interface between an individual payload and the Orbiter is discussed. A simplified, modular thermal control system that will reduce the cost of providing thermal protection by minimizing both the initial procurement cost of any specialized hardware and the need for a detailed thermal interface analysis is described.

Almgren, D. W.↗
NASA NTRS1979

A procedure for determining the optical characteristics of a device for measuring illumination in the atmosphere of Venus

A procedure is described for obtaining the calibration, angular and spectral characteristics of a broad band photometer used on Venera 9 and 10 spacecraft to measure the illuminance regime in five spectral intervals with respect to three directions. The photometer has three identical groups of photoreceivers on which light falls through fiber light guides. Each group contains three cadmium sulfide photoresistors with light filters, a cadmium selenide photoresistor and a silicon photodiode. The temperature of the photoreceivers is measured by thermistors installed in series with the receivers.

Golovin, Y. M.↗
NASA NTRS1978

Proposed design procedure for transmission shafting under fatigue loading

The B106 American National Standards Committee is currently preparing a new standard for the design of transmission shafting. A design procedure, proposed for use in the new standard, for computing the diameter of rotating solid steel shafts under combined cyclic bending and steady torsion is presented. The formula is based on an elliptical variation of endurance strength with torque exhibited by combined stress fatigue data. Fatigue factors are cited to correct specimen bending endurance strength data for use in the shaft formula. A design example illustrates how the method is to be applied.

Loewenthal, S. H.↗
NASA NTRS1978

An apparatus and procedure for evaluating the toxic hazards of smoldering seating and bedding materials

An apparatus and procedure are described for evaluating the toxicity of the gases evolved from the smoldering combustion of seating and bedding materials. The method combines initiation of smoldering combustion in fabric/cushion combinations by a lighted cigarette and exposure of laboratory animals to the gases evolved. The ratio of the surface available for smoldering to the compartment volume in this apparatus is approximately five times the ratio expected in a California living room, and 100 times the ratio expected in a wide-body aircraft passenger cabin. Based on fabric/cushion combinations tested, the toxicity of gases from smoldering combustion does not appear to be a significant hazard in aircraft passenger cabins, but seems to be a basis for careful selection of materials for residential environments.

Hilado, C. J.↗
NASA NTRS1979

Ground attitude determination and gyro calibration procedures for the HEAO missions

The Attitude Ground Support System (AGSS) at Goddard Space Flight Center provides ground attitude support for the High Energy Astronomy Observatory (HEAO) missions. The AGSS uses information telemetered from sun sensors, gyroscopes, star trackers (STAs), and an onboard computer to calculate updates to the onboard attitude reference and gyro calibration parameters. This paper presents the procedures used by the AGSS in computing reference and calibration updates; it also provides HEAO-1 postlaunch statistics that illustrate the ability to maintain 0.25-deg accuracy in the onboard attitude reference. Simulated HEAO-B results show an improvement in reference accuracy through the use of calibration maneuvers.

Fallon, L., III↗
NASA NTRS1978

Procedure for developing experimental designs for accelerated tests for service-life prediction

Recommended design procedures to reduce the complete factorial design by retaining information on anticipated important interaction effects, and by generally giving up information on unconditional main effects are discussed. A hypothetical photovoltaic module used in the test design is presented. Judgments were made of the relative importance of various environmental stresses such as UV radiation, abrasion, chemical attack, temperature, mechanical stress, relative humidity and voltage. Consideration is given to a complete factorial design and its graphical representation, elimination of selected test conditions, examination and improvement of an engineering design, and parametric study. The resulting design consists of a mix of conditional main effects and conditional interactions and represents a compromise between engineering and statistical requirements.

Thomas, R. E.↗