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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Calibration of longwavelength exotech model 20-C spectroradiometer

A brief description of the Exotech model 20-C field spectroradiometer which measures the spectral radiance of a target in the wavelength ranges 0.37 to 2.5 microns (short wavelength unit), 2.8 to 5.6 microns and 7.0 to 14 microns (long wavelength unit) is given. Wavelength calibration of long wavelength unit was done by knowing the strong, sharp and accurately known absorption bands of polystyrene, atmospheric carbon dioxide and methyl cyclohexane (liquid) in the infrared wavelength region. The spectral radiance calibration was done by recording spectral scans of the hot and the cold blackbodies and assuming that spectral radiance varies linearly with the signal.

Kumar, R.↗
NASA NTRS1978

Severe storms

An overview of severe storms given by a representative of the U.S. Department of Commerce/NOAA and how they affect aviation is presented. What is being done and the organizations responsible for the work in this area are briefly discussed. A partial list of the things that the representative feels need to be done is also presented.

Connolly, J. W.↗
NASA NTRS1976

Robot Display and Control program (ROBDAC)

The ROBOT display and control program (ROBDAC) to be written for the Adage 340 computer is designed to communicate with the Univac 1110 computer with the aid of the graphic support communications programs. ROBDAC and the Adage computer act as an input/output device for the program ROBOT, which is run on the Univac 1110. ROBDAC controls the input to ROBOT by displaying images of the inputs, providing an editing technique for these inputs, shipping the input data to the Univac, and then commanding ROBOT to start execution. The output is done in a similar manner after receiving the output data from the Univac. This data will be displayed numerically as well as by plotted graphs. All of the input/output will be done interactively with practically 'finger tip' control. A general program flow diagram of ROBDAC is included.

Stewart, W. A.↗
NASA NTRS1979

A comparison of theoretical and experimental video compression designs

This paper compares theoretical and experimental picture compression designs, for images processed in 8 x 8 blocks using the Walsh-Hadamard transform (WHT). The optimum picture compression design is well known, if the mean-square error (mse) is used as the measure of distortion, and if it is assumed that the video process is a stationary first-order Markov process with a Gaussian distribution. This theoretical design gives useful results when the transform processing is done on full pictures, but gives inferior results (relative to empirical design) when transform processing is done on small 8 x 8 blocks. The use of non-Gaussian distributions for the transform components fails to improve this poor performance, which is due to the nonstationary nature of the video process. An experimentally based design procedure, which considers nonstationarity, yields significantly improved mse and subjective performance.

Jones, H. W., Jr.↗
NASA NTRS1979

Calibration of long wavelength Exotech model 20C spectroradiometer

A brief description of the Exotech model 20C field spectroradiometer, which measures the spectral radiance of a target in the wavelength ranges from 0.37 to 2.5 microns (short wavelength unit), 2.8 to 5.6 microns, and 7.0 to 14 microns (long wavelength unit) is given. It is a rugged field instrument which uses four circular-variable-filters to get wavelength scan. Wavelength calibration of the long wavelength unit was done by use of the strong, sharp, and accurately known absorption bands of polystyrene, atmospheric carbon dioxide, and methyl cyclohexane (liquid) in the IR wavelength region. The spectral radiance calibration was done by recording spectral scans of the hot and the cold blackbody targets and assuming that spectral radiance varies linearly with the signal.

Kumar, R.↗
NASA NTRS1981

Assessment of disk MHD generators for a base load powerplant

Results from a study of the disk MHD generator are presented. Both open and closed cycle disk systems were investigated. Costing of the open cycle disk components (nozzle, channel, diffuser, radiant boiler, magnet and power management) was done. However, no detailed costing was done for the closed cycle systems. Preliminary plant design for the open cycle systems was also completed. Based on the system study results, an economic assessment of the open cycle systems is presented. Costs of the open cycle disk conponents are less than comparable linear generator components. Also, costs of electricity for the open cycle disk systems are competitive with comparable linear systems. Advantages of the disk design simplicity are considered. Improvements in the channel availability or a reduction in the channel lifetime requirement are possible as a result of the disk design.

Chubb, D. L.↗
NASA NTRS1980

A framework for automated decision making and problem solving

Problems can be subdivided into two main categories: well structured problems and ill structured problems. The first require routine repetitive decisions which are generally amenable to programmable decision processes. The second require novel nonprogrammable decision processes. The decision making processes can be subdivided into those representative of those done by humans and those done by machine. Many of such decision processes require a combination of humans d machines. Automated decision making and problem solving technologies are expected to have their greatest potential impact in the space program.

Heer, E.↗
NASA NTRS1981

Some analysis on the diurnal variation of rainfall over the Atlantic Ocean

Data collected from the GARP Atlantic Tropical Experiment (GATE) was examined. The data were collected from 10,000 grid points arranged as a 100 x 100 array; each grid covered a 4 square km area. The amount of rainfall was measured every 15 minutes during the experiment periods using c-band radars. Two types of analyses were performed on the data: analysis of diurnal variation was done on each of grid points based on the rainfall averages at noon and at midnight, and time series analysis on selected grid points based on the hourly averages of rainfall. Since there are no known distribution model which best describes the rainfall amount, nonparametric methods were used to examine the diurnal variation. Kolmogorov-Smirnov test was used to test if the rainfalls at noon and at midnight have the same statistical distribution. Wilcoxon signed-rank test was used to test if the noon rainfall is heavier than, equal to, or lighter than the midnight rainfall. These tests were done on each of the 10,000 grid points at which the data are available.

Gill, T.↗
NASA NTRS1981

Crew activities in space

One of the mission requirements of the Space Shuttle is to serve as a working platform for experiments in space. Many of these experiments will be performed by crewmembers (mission specialists and payload specialists) in a general purpose laboratory called Spacelab. All nonexperiment-related activities or housekeeping activities will be done in the Orbiter, while most of the mission-related activities (experiments) will be done in Spacelab. In order for experimenters to design their experiments to best utilize the capabilities of the Orbiter, the Spacelab, and the crew, the working environment in the Orbiter and in Spacelab is described. In addition, the housekeeping activities required of the crew are summarized.

Bluford, G. S., Jr.↗
NASA NTRS1981

An analysis of LANDSAT MSS scene-to-scene registration accuracy

Measurements were made for 12 registrations done by ERL for 8 registrations done by SRS. The results indicate that the ERL method is significantly more accurate in five of the eight comparison. The difference between the two methods are not significant in the other three cases. There are two possible reasons for the differences. First, the ERL model is a piecewise linear model and the EDITOR model is a cubic polynomial model. Second, the ERL program resamples using bilinear interpolation while the EDITOR software uses a nearest neighbor resampling. This study did not indicate how much of the difference is attributable to each factor. The average of all merged scene error values for ERL was 31.6 meters and the average for the eight common areas was 32.6 meters. The average of the eight merged scene error values for SRS was 40.1 meters.

Seyfarth, B. R.↗
NASA NTRS1982

Data vs. information: A system paradigm

The data system designer requires data parameters, and is dependent on the user to convert information needs to these data parameters. This conversion will be done with more or less accuracy, beginning a chain of inaccuracies which propagate through the system, and which, in the end, may prevent the user from converting the data received into the information required. The concept to be pursued is that errors occur in various parts of the system, and, having occurred, propagate to the end. Modeling of the system may allow an estimation of the effects at any point and the final accumulated effect, and may prove a method of allocating an error budget among the system components. The selection of the various technical parameters which a data system must meet must be done in relation to the ability of the user to turn the cold, impersonal data into a live, personal decision or piece of information.

Billingsley, F. C.↗
NASA NTRS1982

Anion permselective membrane

The synthesis and fabrication of polymeric anion permselective membranes for redox systems are discussed. Variations of the prime candidate anion membrane formulation to achieve better resistance and/or lower permeability were explored. Processing parameters were evaluated to lower cost and fabricate larger sizes. The processing techniques to produce more membranes per batch were successfully integrated with the fabrication of larger membranes. Membranes of about 107 cm x 51 cm were made in excellent yield. Several measurements were made on the larger sample membranes. Among the data developed were water transport and transference numbers for these prime candidate membranes at 20 C. Other work done on this system included characterization of a number of specimens of candidate membranes which had been returned after service lives of up to sixteen months. Work with new polymer constituents, with new N.P.'s, catalysts and backing fabrics is discussed. Some work was also done to evaluate other proportions of the ingredients of the prime candidate system. The adoption of a flow selectivity test at elevated temperature was explored.

Hodgdon, R. B.↗
NASA NTRS1982

GCF Mark IV development

The Mark IV ground communication facility (GCF) as it is implemented to support the network consolidation program is reviewed. Changes in the GCF are made in the area of increased capacity. Common carrier circuits are the medium for data transfer. The message multiplexing in the Mark IV era differs from the Mark III era, in that all multiplexing is done in a GCF computer under GCF software control, which is similar to the multiplexing currently done in the high speed data subsystem.

Mortensen, L. O.↗
NASA NTRS1983

Large space structures control algorithm characterization

Feedback control algorithms are developed for sensor/actuator pairs on large space systems. These algorithms have been sized in terms of (1) floating point operation (FLOP) demands; (2) storage for variables; and (3) input/output data flow. FLOP sizing (per control cycle) was done as a function of the number of control states and the number of sensor/actuator pairs. Storage for variables and I/O sizing was done for specific structure examples.

Fogel, E.↗
NASA NTRS1983

Effects of long duration exposure to simulated space environment on nonmetallic materials properties

Nonmetallic materials specimens from the Viking program were tested in situ invacuo after continuous thermal vacuum exposure from 1971/1972 to the present. Eleven tests were done on appropriate specimens of 30 materials; however, no single material received all the tests. Some specimens also were exposed to 1 or 2.5 MeV electrons at differing fluences before testing. Baseline exposure data is reported for graphite/epoxy specimens that were exposed to vacuum since 1974. These materials were transferred to the thermal vacuum storage facility for future in situ testing and irradiation. Thin G/E specimens were tensile tested after thermal-vacuum cycling exposure. Photomicrographic examinations and SEM analyses were done on the failed specimens.

Peacock, C. L., Jr.↗
NASA NTRS1982

Stereoscopic observations from meteorological satellites

Stereo cloud top height measurements, accurate to within + or - 500 m, have been performed using operational weather satellites. The stereo has been demonstrated using various combinations of GEO and LEO satellites, and the use of synthetic stereo was considered. Stereo can be done over most of the earth (60 deg S to 60 deg N) during the day; at higher latitudes and at night, stereo can be done using two LEOs if the proper coincidences occur. The usefulness of stereo cloud top height measurements has been demonstrated by many studies of convective storm cloud systems. Recommendations relating to short, medium, and long term planning regarding stereo observations from meteorological satellites are outlined.

Hasler, A. F.↗
NASA NTRS1985

Automatic Coal-Mining System

Coal cutting and removal done with minimal hazard to people. Automatic coal mine cutting, transport and roof-support movement all done by automatic machinery. Exposure of people to hazardous conditions reduced to inspection tours, maintenance, repair, and possibly entry mining.

Collins, E. R., Jr.↗