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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 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

A molecular theory of elastomer deformation and rupture.

The mechanical properties of elastomers, including rupture and its time dependence, can be semiquantitatively predicted from nine molecular parameters which are characteristic for a given species, from the initial molecular weight of a sample before cross-linking and from the effective chain concentration (which must still be determined for each vulcanizate). Only two empirical quantities are involved - the Plazek retardation function for entanglement slippage and a related constant which serves to locate this function on the time scale. The theory leads to a new method of estimating fatigue lifetimes from short-time data.

Landel, R. F.↗
NASA NTRS1974

A simplified holographic-interferometry technique for real-time flow visualization and analysis

A holographic-interferometry technique for flow visualization and analysis that produces real-time moire fringes is described from both experimental and application considerations. It has three chief advantages: real-time data for continuous observation and photography, ease of optical adjustment, and capability of using ordinary-glass test-section windows without affecting the results. A theoretical discussion is presented describing the formation of the fringes in holographic terms and then comparing this result to that which is obtained from a conventional moire approach. A discussion on obtaining density information from the fringe pattern is also included.

Long, S. A.↗
NASA NTRS1973

Compendium of meteorological satellites and instrumentation

Pertinent information is presented for 98 launched and planned satellites of the U.S., U.K., U.S.S.R., and France, as well as their over 200 meteorological experiments or instruments. Summary information is provided for both operational and research satellites. Three major sections include: (1) an overview by country, of the various series of meteorological satellite programs; (2) brief descriptions of the satellites and their experiments; and (3) an extensive bibliography. A glossary of acronyms and two indexes for cross-referencing are also included. In addition, various tables and figures presenting satellite operating times, data coverage, location of launch sites, and descriptions of the launch vehicles used to orbit the meteorological satellites are given.

Stoldt, N. W.↗
NASA NTRS1972

High resolution spectroscopic measurements of carbon dioxide and carbon monoxide

A modified 1.83 meter Jarrell-Ash spectrometer is reported. The instrument was double passed and achieved a resolution of 0.05 cm at 15 micrometers. An integrating voltmeter was used to optimize the available integration time. Data were obtained in the 15 micrometer and 4.3 micrometer band of CO2 and the 4.6 micrometer and 2.3 micrometer bands of CO. The data are summarized and examples of typical spectra are given. All the data are stored on IBM cards.

Chaney, L. W.↗
NASA NTRS1974

Program for the analysis of time series

A digital computer program for the Fourier analysis of discrete time data is described. The program was designed to handle multiple channels of digitized data on general purpose computer systems. It is written, primarily, in a version of FORTRAN 2 currently in use on CDC 6000 series computers. Some small portions are written in CDC COMPASS, an assembler level code. However, functional descriptions of these portions are provided so that the program may be adapted for use on any facility possessing a FORTRAN compiler and random-access capability. Properly formatted digital data are windowed and analyzed by means of a fast Fourier transform algorithm to generate the following functions: (1) auto and/or cross power spectra, (2) autocorrelations and/or cross correlations, (3) Fourier coefficients, (4) coherence functions, (5) transfer functions, and (6) histograms.

Brown, T. J.↗
NASA NTRS1973

Role of pH on the stress corrosion cracking of titanium alloys

Stress corrosion cracking (SCC) experiments were conducted on Ti-8-1-1 wire specimens in hydrochloric and sulfuric acids of variable pH in order to determine the effect of pH on the susceptibility to cracking. The alloy exhibited increasing susceptibility with decreasing pH. By varying the applied potential, it was observed that susceptibility zones exist both in the cathodic and the anodic ranges. In the cathodic range, susceptibility also increased with decreasing applied potential. Corrosion potential-time data in hydrochloric acid (pH 1.7) and sulfuric acid (pH 1.7) indicate that chloride ions lower the corrosion potential of the specimen which, in turn, increases the susceptibility.

Khokhar, M. I.↗
NASA NTRS1974

Influence of precision inertial systems on astronomical observations

The incorporation of precision inertial control on LST could exert a strong influence on the philosophy of and techniques for carrying out astronomical observations. In conjunction with a fine guidance star sensor, the inertial reference unit (IRU) described herein could easily expand LST capability to include observations such as (1) tracking of solar system objects, including specific points of interest on the planets; (2) rapid repositioning of scanning sensors on distributed objects such as nebulae and galaxies; (3) carrying out unified star catalog measurements to eliminate the overlap problem which exists in all ground procedures; and (4) carrying out various astrometric measurements with 'real time' data reduction capability.

Ouellette, G. A.↗
NASA NTRS1974

Solar environment support for Skylab

Solar support for the ATM PIs (Apollo Telescope Mount Principle Investigators) and NASA was provided by NOAA's real-time data network through the NOAA-SOLAR facility in the ATM Science Support Room at Mission Control in Houston, Tex. Support was in the form of solar data - e.g., ground-based photographs of H-alpha (hydrogen-alpha), calcium, and magnetograms; voice/teletype reports of activity; analysis and forecasts; and assistance to the PIs and NASA as needed. This required establishing a communication system to a worldwide network of observatories, acquiring data transmission and dissemination equipment, and developing techniques to improve ATM related forecasts. This support began about one month before the first launch of the Skylab series and continued until splashdown of the last mission.

Hirman, J. W.↗
NASA NTRS1975

The use of ERTS imagery in reservoir management and operation

The author has identified the following significant results. Real time data collection by orbiting satellite relay was found to be both reliable and feasible. ERTS imagery was assessed and it was shown that in most cases better spatial resolution and/or additional spectral bands would be required to satisfy NED's needs. A man-computer interactive system, using cathode ray tube display could solve the problem of an unwieldy mass of data for interpretation.

Cooper, S.↗
NASA NTRS1975

On the planetary theory of sunspots

An investigation is conducted of the full tidal problem for Mercury, Venus, Earth, and Jupiter, the tide-raising planets, taking into account the complete orbital elements, including eccentricity, inclination, and their variation with time. Data for a comparison of tidal and sunspot dates are listed in a table. The investigation shows that the alignment of the tide-raising planets within 10 degrees is a common phenomenon, occurring approximately every 10.4 years. This alignment is not associated with drastic tidal effects.

Okal, E.↗
NASA NTRS1975

A generalized expression for lag-time in the gas-phase permeation of hollow tubes

A generalized expression for the nonsteady-state parameter, lag-time, has been obtained from Fick's second law for gas-phase transport through hollow, cylindrical membranes. This generalized expression is simplified for three limiting cases of practical interest: (1) diffusion controlled transport, (2) phase boundary reaction control at the inlet surface, and (3) phase boundary reaction control at the outlet surface. In all three cases the lag-time expressions were found to be inversely proportional only to the diffusion coefficient and functionally dependent on the membrane radii. Finally, the lag-time expressions were applied to experimentally obtained lag-time data for alpha-phase titanium and alpha-phase iron.

Shah, K. K.↗
NASA NTRS1975

The U.S. SEASAT program

The SEASAT program is a space-based operational oceanographic measurement system, which will be capable of providing continuous, all-weather, world-wide, timely data on global ocean dynamics and other physical properties of practical importance to a wide community of governmental and private sector users. This paper describes user requirements, case studies of projected applications, the sensor systems employed, and testing programs.

Mccandless, S. W.↗
NASA NTRS1975

Launch Processing System - A system to support the Space Shuttle

Kennedy Space Center (KSC) is designing and acquiring a Launch Processing System (LPS), an important part of Ground Support Equipment (GSE), to Support launch site operations in a more efficient way than was done on previous programs. LPS will provide (1) automatic control of GSE and Shuttle systems for test and operations, (2) real time data analysis and information display, and (3) efficient recall of test data and engineering files to support Shuttle ground operations. Modern automation techniques, off-the-shelf components, and modular design are being employed to the maximum to achieve these goals. The cost of acquisition, operations, and maintenance of LPS is of great importance and is considered with each engineering trade.

Paul, H. C.↗
NASA NTRS1975

A determination of the lunar moment of inertia

An estimate of the second zonal coefficient of the spherical-harmonic representation of the lunar gravitational field has been obtained from an analysis of particular orbital-element variations of the Explorer 35 and Explorer 49 spacecraft. Data from these spacecraft were used because the orbital configurations resulted in variations of the longitude of periapse and node which were, to first order, dependent only on the even zonal harmonics. The data time span for each satellite was extremely long: 2138 days for Explorer 35 and 230 days for Explorer 49. The value of the harmonic coefficient is determined and used to obtain a value of the lunar moment of inertia.

Gapcynski, J. P.↗
NASA NTRS1975

Passenger comfort response times as a function of aircraft motion

The relationship between a passenger's response time of changes in level of comfort experienced as a function of aircraft motion was examined. The aircraft used in this investigation was capable of providing a wide range of vertical and transverse accelerations by means of direct lift flap control surfaces and side force generator surfaces in addition to normal control surfaces. Response times to changes in comfort were recorded along with the passenger's rating of comfort on a five point scale. In addition, a number of aircraft motion variables including vertical and transverse accelerations were also recorded. Results indicate some relationship between human comfort response times to reaction time data.

Rinalducci, E. J.↗
NASA NTRS1976

The French Atlantic Littoral and the Massif Armoricain

The author has identified the following significant results. Diachronic use of LANDSAT data time series will in time allow study of statistically submerged frequencies in tidal areas. This is an essential element of coastal geomorphology and of coastal zone management, being particularly useful in siting shellfish farms. Maps at useable scales and simple user oriented legends should become an essential document for coastal planning agencies.

Verger, F.↗
NASA NTRS1976

The French Atlantic Littoral and the Massif Armoricain

The author has identified the following significant results. Diachronic use of LANDSAT data time series will in time allow statistical study of submersion frequencies in tidal areas. This is an essential element of coastal geomorphology and of coastal zone management being particularly useful in siting shellfish farms. Maps are being obtained at useable scales and simple, user oriented legends which can be used for coastal planning.

Verger, F.↗
NASA NTRS1976

Soft X-ray observation experiment MA-048

The Apollo Soyuz Test Project Soft X-ray Experiment was designed to observe celestial X-ray sources in the energy range from 0.1 to 10 kiloelectronvolts. The instrument that was used in the experiment obtained energy and fast timing data to characterize both the spectrum and the variability of known X-ray sources. Data were obtained on approximately 12 sources. During the mission, the instrument developed an intermittent high voltage discharge problem that resulted in the loss of approximately 75 percent of the anticipated data, including the scans intended for mapping of the low energy diffuse X-ray background.

Shulman, S.↗