Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “R”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

R. F. testing of the third generation defense communication satellite

The approach taken to test a completed DSCS communications satellite on a system level is described. Areas to be described are measuring RF isolation of separate communications subsystems and a test method which insures that one RF subsystem does not interfere with another. In addition, the method of complying with MIL-STD-1541 in the area of demonstrating safety of electroexplosive devices in an RF field is discussed.

Sargent, J.↗
NASA NTRS1980

Solar power R and D for Air Force space requirements

The requirements for improved solar power system technology for DOD satellites are reported. It is shown that the technology is required in several areas including solar cells, array blanket technology, energy storage and power system operation, and regulation and control. It is further shown that as the missions become more critical to defence, military aspects such as survivability, hardening, and eventually defence must be addressed.

Wise, J. F.↗
NASA NTRS1981

R and D: To fund or not to fund

U.S. Government spending to fund the research and development of electronics for a variety of applications is discussed. Commercial enterprises also spend large sums on research and development of electronics and other areas of interest to the U.S. Government and its agencies. The government can take advantage of industrial research programs and thereby maximize the utilization of their own.

Osterdock, T. N.↗
NASA NTRS1981

NASA aeronautics R&T - A resource for aircraft design

This paper discusses the NASA aeronautics research and technology program from the viewpoint of the aircraft designer. The program spans the range from fundamental research to the joint validation with industry of technology for application into product development. Examples of recent developments in structures, materials, aerodynamics, controls, propulsion systems, and safety technology are presented as new additions to the designer's handbook. Finally, the major thrusts of NASA's current and planned programs which are keyed to revolutionary advances in materials science, electronics, and computer technology are addressed.

Olstad, W. B.↗
NASA NTRS1982

R associations. VI - The reddening law in dust clouds and the nature of early-type emission stars in nebulosity from a study of five associations

Positions, identification charts, UBVRIKLMN photometry and spectral types are given for stars, illuminating reflection nebulae that are visible on the POSS prints, which have been identified in five associations. With a ratio of total to selective extinction of 4.2, the reddening law applicable to the dust clouds in which the stars are embedded is steeper than normal. The five associations exhibit 18 early-type stars with circumstellar shells, of which those with spectral types earlier than B5 characteristically have weak IR excesses, in contrast to the strong excesses indicative of circumstellar dust, of later-type stars. Color-magnitude charts show a distribution lying above the ZAMS by up to about 2 mag for both the circumstellar shell stars and those classified as rapid rotators. It is suggested that (1) rapid rotation accounts for the scatter in the color-magnitude diagram, and (2) many of the nebulous early-type emission-line stars are rapid rotators rather than pre-main sequence objects.

Herbst, W.↗
NASA NTRS1982

IUE observations of R Aquarii

High- and low-dispersion observations made in 1980 are compared with earlier observations. Certain ultraviolet lines are apparently constant in the face of Mira pulsation and rotation and orbital motion of the hypothetical hot companion. Other line features and the ultraviolet continuum vary significantly but not in phase with the Mira. The Mg II doublet profile continued to show an asymmetry that is attributable to 200 km/s mass ejection. The remarkable levelness of the 1300-3100 A continuum (in ergs/sq cm s A) is confirmed, and the suggestion of a hot companion photosphere under circumstellar olivine-smoke extinction is discussed.

Johnson, H. M.↗
NASA NTRS1982

Evaluation of advanced R and D topics in photovoltaics

An evaluation of advanced research and development topics in photovoltaic that is summarized. The intent was to develop priorities in a list of advanced research and development activities. Thirty-five activities in 10 major categories were evaluated by their contributions to basic scientific advances, potential impact on further technology development by private industry, and priorities for federal advanced research and development funding.

Surek, T.↗
NASA NTRS1982

Further observational evidence for a coronal boundary line in the cool star region of the H-R diagram

Soft X-ray emission was detected from Gamma Hya and 37 Com, at levels of 6-8 x 10 to the -13th ergs/sq cm per sec, during 0.2-4.0 keV observations of eight G-K giant stars obtained with the Einstein Observatory's Imaging Proportional Counter. Upper limits of about 3 x 10 to the 13th ergs/sq cm per sec were determined for the remaining stars. These results are judged to strengthen the Ayres et al (1981) findings that stellar coronae whose temperature is greater than one million K are either very weak or entirely absent among red giants and supergiants, while a large range in coronal emission exists among the yellow giant and supergiant stars.

Haisch, B. M.↗
NASA NTRS1983

Ad Hoc modeling, expert problem solving, and R&T program evaluation

A simplified cost and time (SCAT) analysis program utilizing personal-computer technology is presented and demonstrated in the case of the NASA-Goddard end-to-end data system. The difficulties encountered in implementing complex program-selection and evaluation models in the research and technology field are outlined. The prototype SCAT system described here is designed to allow user-friendly ad hoc modeling in real time and at low cost. A worksheet constructed on the computer screen displays the critical parameters and shows how each is affected when one is altered experimentally. In the NASA case, satellite data-output and control requirements, ground-facility data-handling capabilities, and project priorities are intricately interrelated. Scenario studies of the effects of spacecraft phaseout or new spacecraft on throughput and delay parameters are shown. The use of a network of personal computers for higher-level coordination of decision-making processes is suggested, as a complement or alternative to complex large-scale modeling.

Silverman, B. G.↗
NASA NTRS1983

The delta S (delta R)-2 question: The pulse-length dependence of signal power for Fresnel scatter

It is proposed that the enhanced echoes from the atmosphere observed with a vertically pointing radar are due to reflections from horizontally stratified layers. The general case in which there are many closely spaced layers at random heights is called Fresnel scatter. The variation of received power with transmitter pulse length is examined for various models of Fresnel backscatter. It is shown that for the model most often used in previous work, the power is proportional to the pulse length, and not to the pulse length squared. However, for more general models a more complex pulse length dependence is found.

Hocking, W. K.↗
NASA NTRS1984

Twelfth NASTRAN (R) Users' Colloquium

NASTRAN is a large, comprehensive, nonproprietary, general purpose finite element computer code for structural analysis. The Twelfth Users' Colloquim provides some comprehensive papers on the application of finite element methods in engineering, comparisons with other approaches, unique applications, pre and post processing or auxiliary programs, and new methods of analysis with NASTRAN.

Source record↗
NASA NTRS1984

Infrared observations of dust cloud structure in young R associations - NGC 1333, S68, and NGC 7129

Infrared photometry is presented from 1 to 100 microns of the major sources of luminosity in three regions of star formation which contain young B and A, but not O, stars. The reflection nebulae in all three regions are sources of 100-micron emission similar to previously observed optical reflection nebulae. All three regions also contain highly obscured sources which are often associated with radio maser activity, high-velocity gas outflows, and unusual radio continuum emission. There is a strong correlation between the occurrence of these radio phenomena and the presence of dust close enough to the central objects to radiate strongly in the 3-20 micron spectral region. These obscured sources are likely to be the pre-main-sequence counterparts to the nearby visible main-sequence stars; the obscured objects may still be undergoing mass accretion.

Wilking, B. A.↗
NASA NTRS1984

Physics of the inner heliosphere 1-10R sub O plasma diagnostics and models

The physics of solar wind flow in the acceleration region and impulsive phenomena in the solar corona is studied. The study of magnetohydrodynamic wave propagation in the corona and the solutions for steady state and time dependent solar wind equations gives insights concerning the physics of the solar wind acceleration region, plasma heating and plasma acceleration processes and the formation of shocks. Also studied is the development of techniques for placing constraints on the mechanisms responsible for coronal heating.

Withbroe, G. L.↗
NASA NTRS1985

NASA R and T aerospace plane vehicles: Progress and plans

Progress made in key technologies such as materials, structures, aerothermodynamics, hypersonic aerodynamics, and hypersonic airbreathing propulsion are reported. Advances were made in more generic, areas such as active controls, flight computer hardware and software, and interdisciplinary analytical design methodology. These technology advances coupled with the development of and experiences with the Space Shuttle make feasible aerospace plane-type vehicles that meet the more demanding requirements of various DOD missions and/or an all-weather Shuttle II with reduced launch costs. Technology needs and high payoff technologies, and the technology advancements in propulsion, control-configured-vehicles, aerodynamics, aerothermodynamics, aerothermal loads, and materials and structures were studied. The highest payoff technologies of materials and structures including thermal-structural analysis and high temperature test techniques are emphasized. The high priority technology of propulsion, and plans, of what remains to be done rather than firm program commitments, are briefly discussed.

Dixon, S. C.↗
NASA NTRS1985

Thirteenth NASTRAN (R) Users' Colloquium

The application of finite element methods in engineering is discussed and the use of NASTRAN is compared with other approaches. Specific applications, pre- and post-processing or auxiliary programs, and additional methods of analysis with NASTRAN are covered.

Source record↗