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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 NTRS1985

An analysis of the bright white dwarf CD - 38 deg 10980

The bright DA white dwarf CD - 38 deg 10980 is comprehensively analyzed using all available data. Detailed comparisons of the overall energy distribution and Lyman-alpha and Balmer profiles are made with theoretical predictions based on a homogeneous grid of model atmospheres. These comparisons yield a consistent, well-defined effective temperature and surface gravity for this star of 24,700 + or - 250 K and log g = 7.95 + or - 0.15, respectively. A new gravitational redshift of 28.4 + or - 4.8 km/s is derived from an IUE high-dispersion spectrum. Conclusions regarding the mass and radius of CD - 38 deg 10980 are also presented.

Holberg, J. B.↗
NASA NTRS1986

The heat of formation of Mercury vacancies in Hg(0.8)Cd(0.2)Te

A modified mass loss measurement technique has been employed for the first time for the direct in situ determination of vacancy concentrations in Hg(0.8)Cd(0.2)Te at elevated temperatures. This technique can also be used to establish the pressure-temperature phase diagram for this type of system. The derived mean value for the heat of formation of mercury vacancies in the above alloy is 0.43 eV. Theoretical considerations concerning the vacancy formation in HgTe and in Hg(0.8)Cd(0.2)Te are in qualitative agreement with the experimental value.

Wiedemeier, H.↗
NASA NTRS1988

Growth and characterization of Hg(1-x)Cd(x)Se alloys

A detailed evaluation of the influence of growth conditions on the radial and axial compositional variations in directionally solidified Hg(1-x)Cd(x)Se alloys was performed. The measured axial compositional profiles were fitted to theoretical profiles to determine the effective solute (CdSe) diffusion coefficient (D) for the Hg(1-x)Cd(x)Se system. The value for D was estimated to be 3.0 + or - 0.5 x 10 to the -5th sq cm/s and did not appear to be significantly affected by the rate of crystal growth. The axial crystal uniformity was shown to be highly growth-rate dependent, with the faster growth rates producing crystals of more uniform composition in the axial direction. The magnitude of the radial variations was also shown to be highly growth-rate dependent, with the slower growth rates producing crystals of greater radial uniformity. This translation rate dependence of the radial uniformity is discussed in terms of lateral solute diffusion and convective interfacial fluid flows.

Andrews, R. N.↗
NASA NTRS1990

Alignment of cD-galaxies with their surroundings

For a sample of 122 rich Abell clusters the authors find a strong correlation of the position angle (orientation) of the first-ranked galaxy and its parent cluster. This alignment effect is strongest for cD-galaxies. Formation scenarios for cD galaxies, like the merging scenario, must produce such a strong alignment effect. The authors show some N-body simulations done for this purpose.

Vankampen, Eelco↗
NASA NTRS1989

Purification, growth, and characterization of Zn(x)Cd(1-x)Se crystals

The purification of starting materials which were used in the growth of Zn(x)Cd(1-x)Se (x = 0.2) single crystals using the traveling solution method (TSM) is reported. Up to 13 cm long single crystals and as grown resistivities of 6 x 10(exp 12) ohm/cm could be achieved. Infrared and Raman spectra of Zn(0.2)Cd(0.8)Se are also presented and discussed.

Silberman, E.↗
NASA NTRS1992

Publication Of Oceanographic Data on CD-ROM

Large collections of oceanographic data and other large collections of data published on CD-ROM's in formats facilitating access and analysis. Involves four major steps: preprocessing, premastering, mastering, and verification. Large capacity, small size, commercial availability, long-life, and standard format of CD-ROM's offer advantages over computer-compatible magnetic tape.

Hilland, Jeffrey E.↗
NASA NTRS1992

Life evaluation of 35Ah Ni-Cd cell in Japan

The National Space Development Agency of Japan (NASDA) began developing Nickel-Cadmium (Ni-Cd) cells for space use in 1985. Sanyo Electric was responsible for the cell design, manufacturing, and initial testing. The cell life was evaluated by NASDA in the Tsukuba Space Center (TKSC). The development is presently in the qualification Test (QT) phase. Recent life-cycle data for 35 Ah Ni-Cd cells are presented.

Kuwajima, S.↗
NASA NTRS1993

Charge-carrier mobilities in Cd(0.8)Zn(0.2)Te single crystals used as nuclear radiation detectors

Charge-carrier mobilities were measured for the first time in Cd(0.8)Zn(0.2)Te single crystals using time-of-flight measurements of charge carriers produced by short (10 ns) light pulses from a frequency-doubled Nd:YAG laser (532 nm). The electron mobility displayed a T exp -1.1 dependence on the absolute temperature T in the range 200-320 K, with a room-temperature mobility of 1350 sq cm/V s. The hole mobility displayed a T exp -2.0 dependence in the same temperature range, with a room-temperature mobility of 120 sq cm/V s. Cd(0.8)Zn(0.2)Te appears to be a very favorable material for a room-temperature electronic nuclear radiation detector.

Burshtein, Z.↗
NASA NTRS1992

Closed-ampoule diffusion of sulfur into Cd-doped InP substrates - Dependence of S profiles on diffusion temperature and time

In order to optimize the fabrication of n(+)-p InP solar cells made by closed-ampoule diffusion of sulfur into p-InP:Cd substrates, we have investigated the influence of diffusion conditions on sulfur diffusion profiles. We show that S diffusion in InP is dominated by the P vacancy mechanism and is not characterized by a complementary error function as expected for an infinite source diffusion. The S diffusion mechanism in p-InP is qualitatively explained by examining the depth profiles of S, P, and In in the emitter layer and by taking into account the presence and composition of different compounds found to form in the In-P-S-O-Cd system as a result of diffusion.

Faur, Mircea↗
NASA NTRS1993

Dynamics of cD clusters of galaxies. I - Redshift data for seven clusters

We present the initial results of a spectroscopic study of a sample of cD galaxy clusters. The goal of this program is to study the dynamics of the clusters, with emphasis on determining the nature and frequency of peculiar velocity cD galaxies. In this paper we present redshifts for 611 galaxies in the fields of the rich Abell clusters A193, A399, A401, A1795, A1809, A2063, and A2124. We discuss our data reduction techniques, and compare our derived velocities with previously published values. We find a frequency of emission line galaxies of about 6 percent in clusters, a factor of 2-3 less than the field.

Hill, John M.↗
NASA NTRS1995

NASA and CD Radio's TDRSS industrial test program

The National Aeronautics and Space Administration (NASA) has embarked on a joint test program with CD Radio Inc. The program will demonstrate spatial diversity techniques in support of industrial development of a new satellite direct broadcast national radio service called Satellite Radio. Satellite Radio will operate in the FCC approved frequency band 2310-2360 MHz which is close to NASA's Tracking and Data Relay System (TDRSS) satellites' high power transmit frequency near 2110 MHz. The cooperative test program in which NASA provides use of a TDRSS satellite and CD Radio provides the measurement equipped vehicle is described as well as its current status. Some initial measurement data are presented.

Briskman, Robert D.↗
NASA NTRS1996

An analyses of CD-ROM technology for spacelink

This study first examined the possibility of placing NASA CD's in the Spacelink Public Electronic Library (SPEL). The goal of this task was to place these materials on the Internet. The second part of the study addressed the possibility of using CD's as storage for portions of SPEL. These files would also be on the Internet and available to the users of Spacelink.

Smith, Willard A.↗
NASA NTRS2000

X-37 CD Rom (Mini Business Card Version)

The mini X-37 CD was developed as an educational tool for the public and commercial industry about the X-37 pathfinder vehicle program. This CD contains overview information about the X-37 program along with general vehicle system and technology description information.

Stewart, Scotty↗
NASA NTRS2001

Shuttle-Mir, CD-ROM Supplement

This CD-ROM is a companion to an illustrated history book with the same title. This multi-media, searchable CD includes the full text and images in the book, as well as additional material. Interviews, photographs, and biographies of the U.S. Astronauts, cosmonauts, and team members for the Shuttle-Mir Program are available. STS Mission Summaries for each mission involved can be viewed, including launch and landing details, crew lists, and mission highlights. Photographs and videos from each mission are included, as well as diagrams of different spacecraft, and computer-generated animations of the Mir deorbit, collision, and flyaround. Additional documents include mission status reports, published documents, news releases, personal letters, and oral histories. The experiments carried out on Mir are described, highlighting combustion and fluid physics research, life in microgravity, and research of the development of the solar system. The focus on improving space technology and planning for the International Space Station is explained. The main features of the book itself include: (1) Training and Operations; (2) Long Duration Psychology; (3) Bilingual Blues; and (4) Earth Observations.

Morgan, Clay↗
NASA NTRS1986

The purification and properties of a cd-cytochrome nitrite reductase from Paracoccus halodenitrificans

Paracoccus halodenitrificans, grown anaerobically in the presence of nitrite, contained membrane and cytoplasmic nitrite reductases. When assayed in the presence of phenazine methosulfate and ascorbate, the membrane-bound enzyme produced nitrous oxide whereas the cytoplasmic enzyme produced nitric oxide. When both enzymes were assayed in the presence of methyl viologen and dithionite, the cytoplasmic enzyme produced ammonia. Following solubilization, the membrane-bound enzyme behaved like the cytoplasmic enzyme, producing nitric oxide in the presence of phenazine methosulfate and ascorbate, and ammonia when assayed in the presence of methyl viologen and dithionite. The cytoplasmic and membrane-bound enzymes were purified to essentially the same specific activity. Only a single nitrite-reductase activity was detected on electrophoretic gels and the electrophoretic behavior of both enzymes suggested they were identical. The spectral properties of both enzymes suggested they were cd-type cytochromes. These data suggest that the products of nitrite reduction by the cd-cytochrome nitrite reductase are determined by the location of the enzyme and the redox potential of the electron donor.

NASA Center ARC↗
NASA NTRS2002

NASA Space Mechanisms Handbook and Reference Guide Expanded Into CD-ROM Set

Several NASA missions suffered failures and anomalies due to problems in applying space mechanisms technology to specific projects. Research shows that engineers often lack either adequate knowledge of mechanism design or sufficient understanding of how mechanisms affect sensitive systems. The Space Mechanisms Project conducted a Lessons Learned study and published a Space Mechanisms Handbook to help space industry engineers avoid recurring design, qualification, and application problems. The Space Mechanisms Handbook written at the NASA Glenn Research Center details the state-of-the-art in space mechanisms design as of 1998. NASA's objective in developing this Space Mechanisms Handbook was to provide readily accessible information on such areas as space mechanisms design, mechanical component availability and use, testing and qualification of mechanical systems, and a listing of worldwide space mechanisms experts and testing facilities in the United States. This handbook has been expanded into a two-volume CD-ROM set in an Adobe Acrobat format. In addition to the handbook, the CD's include (1) the two volume Space Mechanisms Lessons Learned Study, (2) proceedings from all the NASA hosted Aerospace Mechanisms Symposia held through the year 2000, (3) the Space Materials Handbook, (4) the Lubrication Handbook for the Space Industry, (5) the Structural & Mechanical Systems Long-Life Assurance Design Guidelines, (6) the Space Environments and Effects Source-Book, (7) the Spacecraft Deployable Appendages manual, (8) the Fastener Design Manual, (9) A Manual for Pyrotechnic Design, Development and Qualification, (10) the Report on Alternative Devices to Pyrotechnics on Spacecraft, and (11) Gearing (a manual). In addition, numerous other papers on tribology and lubrication are included.This technical summary of the project provides information on how to obtain the handbook and related information.

Fusaro, Robert L.↗
NASA NTRS1993

Pre-Mastering and CD-WO Evaluations

This article reviews the features and functionality of five desktop pre-mastering software packages for the PC. Desktop pre-mastering packages are aimed primarily at end-users interested in bringing CD-ROM publishing tasks in-house, rather than traditional CD-ROM developers.

software packages multi-platform CDs PC Macintosh ↗
NASA NTRS2013

Metal-Silicate Partitioning of Bi, In, and Cd as a Function of Temperature and Melt Composition

The origin of volatile elements in the Earth, Moon and Mars is not known; however, several theories have been proposed based on volatile elements such as In, As, Se, Te and Zn which are in lower concentration in the Earth, Moon, and Mars than in chondrites. Explanations for these low concentrations are based on two contrasting theories for the origin of Earth: equilibrium core formation versus late accretion. One idea is that the volatiles were added during growth of the planets and Moon, and some mobilized into the metallic core while others stayed in the mantle (e.g., [1]). The competing idea is that they were added to the mantles after core formation had completed (e.g., [2]). Testing these ideas involves quantitative modeling which can only be performed after data is obtained on the systematic metal-silicate partitioning behavior of volatile elements with temperature, pressure and melt composition. Until now, such data for Bi, In, and Cd has been lacking. After conducting a series of high pressure, high temperature experiments, the metal-silicate partition coefficients of Bi, In, and Cd as a function of temperature and melt composition can be used to evaluate potential conditions under which terrestrial planets differentiated into core and mantle, and how they acquired volatiles.

Marin, Nicole↗