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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Foundations of planetary quarantine.

Discussion of some of the problems in microbiology and engineering involved in the implementation of planetary quarantine. It is shown that the solutions require new knowledge in both disciplines for success at low cost in terms of both monetary outlay and man's further exploration of the planets. A related problem exists in that engineers are not accustomed to the wide variation of biological data and microbiologists must learn to work and think in more exact terms. Those responsible for formulating or influencing national and international policies must walk a tightrope with delicate balance between unnecessarily stringent requirements for planetary quarantine on the one hand and prevention of contamination on the other. The success of planetary quarantine measures can be assured only by rigorous measures, each checked, rechecked, and triple-checked to make sure that no errors have been made and that no factor has been overlooked.

Hall, L. B.↗
NASA NTRS1973

Low-cost coding techniques for digital fault diagnosis

Published report discusses fault location properties of arithmetic codes. Criterion for effectiveness of given code is detection probability of local fault by application of checking algorithm to results of entire set of algorithms of processor. Report also presents analysis of arithmetic codes with low-cost check algorithm which possesses partial fault-location properties.

Avizienis, A. A.↗
NASA NTRS1974

Input-output, expandable-parity network

Large-scale integrated circuit generates and checks parity of four eight-bit registers. In addition, circuit will indicate by output signal whether parity error exists. Circuit can also generate or check parity of words up to 32 bits. This is done by making appropriate internal wiring connections on the large-scale integrated chip.

Mckevitt, J. F., III↗
NASA NTRS1972

Geology of Utah and Nevada by ERTS imagery

The author has identified the following significant results. Imagery for a portion of the study area was received, catalogued for in-house availability, and examined for relevant data. Topographic, geologic, aeromagnetic, and gravity maps were gathered to form a basis of comparison. Overlay drawings were prepared indicating significant features for further study and eventual field checking. The number of significant observations appears to be very great, and it is apparent that methods of handling the acquired information for easy access, for planning field checks, and for final presentation, must be improved. The tracing of lithologic variations and contacts is readily noted on many of the images. Some of the features vary from what is shown on geological maps but the correlation, or lack of same, is still to be studied in the field and by comparison of ground truth geological maps with the specific images. Numerous lineaments, based on tonal differences, are noted in the districts, some of which extend for tens of kilometers. Several positive and negative magnetic anomalies are noted with the suggestion that the sources of the mineralizing fluids were derived from hidden intrusives.

Jensen, M. L.↗
NASA NTRS1973

Generalize aerodynamic coefficient table storage, checkout and interpolation for aircraft simulation

The set of programs described has been used for rapidly introducing, checking out and very efficiently using aerodynamic tables in complex aircraft simulations on the IBM 360. The preprocessor program reads in tables with different names and dimensions and stores then on disc storage according to the specified dimensions. The tables are read in from IBM cards in a format which is convenient to reduce the data from the original graphs. During table processing, new auxiliary tables are generated which are required for table cataloging and for efficient interpolation. In addition, DIMENSION statements for the tables as well as READ statements are punched so that they may be used in other programs for readout of the data from disc without chance of programming errors. A quick data checking graphical output for all tables is provided in a separate program.

Neuman, F.↗
NASA NTRS1972

Prototype data terminal: Multiplexer/demultiplexer

The design and operation of a quad redundant data terminal and a multiplexer/demultiplexer (MDU) design are described. The most unique feature is the design of the quad redundant data terminal. This is one of the few designs where the unit is fail/op, fail/op, fail/safe. Laboratory tests confirm that the unit will operate satisfactorily with the failure of three out of four channels. Although the design utilizes state-of-the-art technology. The waveform error checks, the voting techniques, and the parity bit checks are believed to be used in unique configurations. Correct word selection routines are also novel, if not unique. The MDU design, while not redundant, utilizes, the latest state-of-the-art advantages of light couplers and integrated circuit amplifiers.

Leck, D. E.↗
NASA NTRS1972

Large deflection elastic-plastic dynamic response of stiffened shells of revolution

The formulation and check out porblems for a computer code DYNAPLAS, which analyzes the large deflection elastic-plastic dynamic response of stiffened shells of revolution, are presented. The formulation for special discretization is by the finite element method with finite differences being used for the evaluation of the pseudo forces due to material and geometric nonlinearities. Time integration is by the Houbolt method. The stiffeners may be due to concentrated or distributed eccentric rings and spring supports at arbitrary angles around the circumference of the elements. Check out porblems include the comparison of solutions from DYNAPLAS with experimental and other computer solutions for rings, conical and cylindrical shells and a curved panel. A hypothetical submarine including stiffeners and missile tube is studied under a combination of hydrostatic and dynamically applied asymmetrical pressure loadings.

Stricklin, J. A.↗
NASA NTRS1973

Determination of the distribution of sound source intensities in subsonic and supersonic jets

Equations relating crossed beam space-time correlations to the sound source strength per unit length of an idealized jet are presented and applied to actual measurements in unheated jets at M = 0.71 and M = 1.0. The infrared crossed beam system was assembled and checked out. The prediction of the system's insensitivity to temperature fluctuations when set at 4.31 microns with a 0.08 micron bandpass was checked. Relative intensity profiles of density fluctuations for jets at M = 0.71, 1.0 and 1.94 were measured. These profiles differ considerably from velocity fluctuation profiles measured by other investigators with hotwires. The convection speeds also differ. Finally, the sound source strengths per unit length are obtained at various axial distances for the subsonic and sonic jet. The sonic jet shows peak source strength at an axial distance of six diameters.

Damkevala, R. J.↗
NASA NTRS1973

SAFE - Six axis frequency evaluation of a motion simulator.

SAFE is a digital computer program used to check the response of an aircraft motion simulator. SAFE drives each axis of the simulator near its acceleration, velocity and position limits, recording the simulator motions for comparison with nominal responses. SAFE also drives up to six axes at once to measure the frequency response and noise levels of each axis. Together these two measurements provide a sensitive check of the entire motion system, yet they can be completed in less than ten minutes.

Shirley, R. S.↗
NASA NTRS1973

NASA-6 atmospheric measuring station

Information required to calibrate, functionally check, and operate the Instrumentation Branch equipment on the NASA-6 aircraft is provided. All procedures required for preflight checks and in-flight operation of the NASA-6 atmospheric measuring station are given. The calibration section is intended for only that portion of the system maintained and calibrated by IN-MSD-12 Systems Operation contractor personnel. Maintenance is not included.

Source record↗
NASA NTRS1973

Software approach to automatic patching of analog computer

The Automatic Patching Verification program (APV) is described which provides the hybrid computer programmer with a convenient method of performing a static check of the analog portion of his study. The static check insures that the program is patched as specified, and that the computing components being used are operating correctly. The APV language the programmer uses to specify his conditions and interconnections is similar to the FORTRAN language in syntax. The APV control program reads APV source program statements from an assigned input device. Each source program statement is processed immediately after it is read. A statement may select an analog console, set an analog mode, set a potentiometer or DAC, or read from the analog console and perform a test. Statements are read and processed sequentially. If an error condition is detected, an output occurs on an assigned output device. When an end statement is read, the test is terminated.

Source record↗
NASA NTRS1974

Large deflection elastic-plastic dynamic response of stiffened shells of revolution

This paper presents the formulation and check-out problems for a computer code DYNAPLAS, which analyzes the large deflection elastic-plastic dynamic response of stiffened shells of revolution. The formulation for spacial discretization is by the finite element method with finite differences being used for the evaluation of the pseudo forces due to material and geometric nonlinearities. Time integration is by the Houbolt method or central differences. The stiffeners may be due to concentrated or distributed eccentric rings and spring supports at arbitrary angles around the circumference of the elements. Check-out problems include the comparison of solutions from DYNAPLAS with experimental and other computer solutions for rings and conical and cylindrical shells. A hypothetical submarine including stiffeners and missile tube is studied under a combination of hydrostatic and dynamically applied asymmetrical pressure loadings.

Stricklin, J. A.↗
NASA NTRS1975

Digital tape drive monitor

Network checks skew and character spacing of digital tape drive systems automatically. Tape drive is set up and calibrated to check any written tape when tape is read back. It will indicate track errors or character spacing errors should they exceed specifications.

Mckenna, R. T.↗
NASA NTRS1975

Computerized processing of data from Interkosmos-7 and Interkosmos-8 satellite experiments

Computerized data processing problems are analyzed using telemetry data received from Intercosmos-7 and Intercosmos-8 satellites. Problems related to the restoration of measurement data in the form of piecewise continuous and smooth calibrated functions of time and problems encountered in the scientific interpretation of the experimental results are considered. Curve smoothing is discussed in the case of distinct assignments of calibration levels, synchronization, and synchronization checks over time. A proposal is presented for checking a piecewise linear function providing a simple method for the elimination of isolated values due to channel failures and the separation of individual intervals.

Pfau, H.↗
NASA NTRS1975

Algorithms

The implementation of the algorithms used in the flight program to approximate elementary functions and mathematical procedures was checked. This was done by verifying that at least one, and in most cases, more than one function computed through the use of the algorithms was calculated properly. The following algorithms were checked: sine-cosine, arctangent, natural logarithm, square root, inverse square root, as well as the vector dot and cross products.

Source record↗
NASA NTRS1976

LACIE performance predictor final operational capability program description, volume 1

The program EPHEMS computes the orbital parameters for up to two vehicles orbiting the earth for up to 549 days. The data represents a continuous swath about the earth, producing tables which can be used to determine when and if certain land segments will be covered. The program GRID processes NASA's climatology tape to obtain the weather indices along with associated latitudes and longitudes. The program LUMP takes substrata historical data and sample segment ID, crop window, crop window error and statistical data, checks for valid input parameters and generates the segment ID file, crop window file and the substrata historical file. Finally, the System Error Executive (SEE) Program checks YES error and truth data, CAMS error data, and signature extension data for validity and missing elements. A message is printed for each error found.

Source record↗
NASA NTRS1975

On the invertibility of linear multivariable systems

Some results concerning invertibility of a class of linear, time-invariant systems are presented. It is shown that by an appropriate factorization of the transfer matrix of such a system, the problem of checking its invertibility can be reduced to that of checking the invertibility of a lower-order system. A sufficient condition for invertibility is also obtained.

Patel, R. V.↗