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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 1,495 records · Page 83
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Preparation of Flight Operations and IWS Integration of the CELIAS Experiment on the SOHO Spacecraft

During this reporting time period, the following activities took place: (1) generation of several versions of the CELIAS (STOF/SEM/CTOF/MTOF/DPU) commissioning timeline for the first 180 days after launch; (2) identification of several problems with the CELIAS portion of the Project Data Base (PDB); (3) attendance of the Science Operations Working Group (SOWG) Meetings (November 1994, February 1995, May 1995) and Flight Operations Review Meeting (July 1995); (4) participation in Flight Operation Simulations SIM 1 (November 14-18, 1994), SIM 2 (May 1-4, 1995) and SIM3 (August 7-11, 1995); and (5) participation in the Ground System Compatibility Test Rehearsal (April 24-28) 1995), GSCT #2 (May 30-June 14, 1995), GSCT #3 (September 12-22 1995), and GSCT #4b (October 30-November 5, 1995).

Ipavich, Fred↗
NASA NTRS1995

Ferrix Chloride-Graphite Intercalation Compounds Prepared From Graphite Flouride

The reaction between graphite fluoride and ferric chloride was observed in the temperature range of 300 to 400 C. The graphite fluorides used for this reaction have an sp(sup 3) electronic structure and are electrical insulators. They can be made by fluorinating either carbon fibers or powder having various degrees of graphitization. Reaction is fast and spontaneous and can occur in the presence of air. The ferric chloride does not have to be predried. The products have an sp(sup 2) electronic structure and are electrical conductors. They contain first-stage FeCl3 intercalated graphite. Some of the products contain FeCl2 (center dot) 2H2O, others contain FeF3, in concentrations that depend on the intercalation condition. The graphite intercalated compounds (GIC) deintercalated slowly in air at room temperature, but deintercalated quickly and completely at 370 C. Deintercalation is accompanied by the disappearance of iron halides and the formation of rust (hematite) distributed unevenly on the fiber surface. When heated to 400 C in pure N2 (99.99 vol%), this new GIC deintercalates without losing its molecular structure. However, when the compounds are exposed to 800 C N2, in a quartz tube, they lost most of their halogen atoms and formed iron oxides (other than hematite), distributed evenly in or on the fiber.

Hung, Ching-Cheh↗
NASA NTRS1995

Teacher Enhancement and Preparation Programs

These two programs provide opportunities for K-12 teachers of mathematics, science, and technology to spend two weeks at a NASA center learning about aeronautics and space. Participants are selected by peer review from a contracting agent that assists NASA in administering the program. Each teacher receives a stipend that covers the cost of travel, housing, meals, and graduate credit. NEWMAST provides for approximately 100 secondary teachers, and NEWTEST is a program designed to meet the needs of approximately 125 elementary teachers each summer. Teachers are provided with a wide variety of experiences including research laboratory observations, presentations, and 'shadowships'. Individual and team projects are used to enhance the participants knowledge of space and aeronautics and to motivate the teachers to incorporate the summer workshop activities into their classrooms.

Source record↗
NASA NTRS1996

Preparation and Properties of High-T(sub c) Bi-Pb-Sr-Ca-Cu-O Thick Film Superconductors on YSZ Substrates

An evaluation of four firing profiles was performed to determine the optimum processing conditions for producing high-T(sub c) Bi-Pb-Sr-Ca-Cu-O thick films on yttria-stabilized zirconia substrates. Using these four profiles, the effects of sintering temperatures of 830-850 C and soak times of 0.5 to 12 hours were examined. In this study, T-c, zero values of 100 K were obtained using a firing profile in which the films were sintered for 1.5 to 2 hours at 840 to 845 C and then quenched to room temperature. X-ray diffraction analyses of these specimens confirmed the presence of the high-T(sub c) phase. Films which were similarly fired and furnace cooled from the peak processing temperature exhibited a two-step superconductive transition to zero resistance, with T-c,zero values ranging from 85 to 92 K. The other firing profiles evaluated in this investigation yielded specimens which either exhibited critical transition temperatures below 90 K or did not exhibit a superconductive transition above 77 K.

Hooker, Matthew W.↗
NASA NTRS1997

A Method for Preparation, Storage and Activation of Large Populations of Immotile Sea Urchin Sperm

Reversible protein phosphorylation is associated with initiation and modulation of sperm flagellar motility. Many studies aimed at examining the signal transduction mechanisms underlying the expression of motility have relied on detergent-permeabilized sperm reactivated with exogenous 32 P-ATP. However, the reactivation conditions allow variable levels of motility to be expressed and phosphorylation of many proteins that appear to be unrelated to sperm motility. Thus, identification of the few relevant proteins is difficult. We have developed a method to collect and keep sperm immotile until reactivated for analysis to normal motility levels. Artificial sea water (ASW) buffered with 5 mM 2-[N-morpholino]ethanesulfonic acid at pH 6.0 and containing 50 mM KCI, allows collection and storage of immotile sea urchin sperm for up to 96 h at 4-5 C. Motility under these conditions is essentially zero, but sperm is rapidly reactivated to normal motility by diluting with ASW to standard pH (8.0) and KCI concentration (10 mM).

Bracho, Geracimo E.↗
NASA NTRS1998

Synergistic Airframe-Propulsion Interactions and Integrations: A White Paper Prepared by the 1996-1997 Langley Aeronautics Technical Committee

This white paper addresses the subject of Synergistic Airframe-Propulsion interactions and integrations (SnAPII). The benefits of SnAPII have not been as extensively explored. This is due primarily to the separateness of design process for airframes and propulsion systems, with only unfavorable interactions addressed. The question 'How to design these two systems in such a way that the airframe needs the propulsion and the propulsion needs the airframe?' is the fundamental issue addressed in this paper. Successful solutions to this issue depend on appropriate technology ideas. This paper first details some ten technologies that have yet to make it to commercial products (with limited exceptions) and that could be utilized in a synergistic manner. Then these technologies, either alone or in combination, are applied to both a conventional twin-engine transonic transport and to an unconventional transport, the Blended Wing Body. Lastly, combinations of these technologies are applied to configuration concepts to assess the possibilities of success relative to five of the ten NASA aeronautics goals. These assessments are subjective, but they point the way in which the applied technologies could work together for some break-through benefits.

Yaros, Steven F.↗
NASA NTRS1997

Preparation, Fabrication, and Evaluation of Advanced Polymeric and Composite Materials

The thesis titles are given below: physical and mechanical behavior of amorphous poly(arylene ether-co-imidasole)s and poly(arylene ether-co-imidasole) modification epoxies; the requirements of patentability as applied to the chemical arts; fabrication of thermoplastic polymer composite ribbon; blend of reactive diluents with phenylethynyl-terminated arylene ether oligomers; the synthesis, characterization, and application of ether-containing polyimides; the synthesis of reflective and electrically conductive polyimide films via an in-situ self-metalization procedure using silver (I) complexes; the thermal cure of phenylethynyl terminated polyimides and selected model compounds; and the synthesis, characterization, and molecular modeling of cyclic arylene ether oligomers.

Orwoll, Robert A.↗
NASA NTRS1994

ASU Formula Lightning Race Vehicle Report Prepared for Ohio Aerospace Institute

This report describes the drive system in the Arizona State University Formula Lightning electric race car when it participated in the 1994 Cleveland Electric Formula Classic on 9 July 1994. In addition, the telemetry system used to monitor the car's performance and plans for improving the car's performance are described.

Sirkis, Murray D.↗
NASA NTRS1994

Preparation and Dielectric Measurements of the Rare Earth Green Phases R2BaCuO(5-x) (R = Y, Sm, Gd, Dy, Ho, Er, Yb)

It has been demonstrated that R2BaCuO(5-x) (R = Y, Sm, Gd, Dy, Ho, Er, Yb) does not undergo significant densification unless the sintering temperatures are near the incongruent melting point or the sintering times are long. Good quality powders of Y2BaCuO(5-x) have been synthesized by using oxide raw materials or precursors such as acetates and nitrates. The acetates- and the nitrates-derived yttrium green phase resulted in finer particle sizes, acceptable dielectric properties and lower melting temperatures than those processed via oxide raw materials. The hot pressing technique has been employed to produce a dense R2BaCuO(5-x) (R=Y,Gd) substrate with satisfactory dielectric properties. Reactivity to reducing conditions, i.e. graphite die, limited the optimization of the properties. A high sensitivity to the annealing atmosphere has been demonstrated in Y2BaCuO,.,,. Oxygen treatment at 950 OC has been shown to improve the dielectric properties while treatment in nitrogen, at the same temperature, degraded desirable properties. A high sensitivity to the annealing atmosphere has been demonstrated in Y2BaCuO(5-x). Oxygen treatment at 950 C has been shown to improve the dielectric properties while treatment in nitrogen, at the same temperature, degraded desirable properties. The dielectric constants of the rare earth green phases R2BaCuO(5-x) were found to be low. Relaxation peaks were detected at low temperatures (T less than 150 K) and at high temperatures (150 less than T greater than 420 K). The dielectric losses and conductivities at 77 K were measured to be in the range of 10(exp -4) and 10(exp -12) (Omega-cm)(exp -1), respectively. Many parameters were found to exhibit dependencies on the rare earth cation sizes.

Gonzalez-Titman, Carlos↗
NASA NTRS1997

Development of Gravity-Sensing Organs in Altered Gravity Conditions: Opposite Conclusions From an Amphibian and a Molluscan Preparation

Several components of the systems animals use to orient to gravity might develop differently in micrograms. If the growth of the "test masses" on which gravity acts (otoliths, in vertebrates, statoliths or statoconia in most invertebrates) is controlled on the basis of their weight, larger otoliths (or their analogs) would be expected to develop in micrograms. The vestibular systems in animals reared in altered gravity have been studied in several species, with varied results being reported. Early Russian reports of Xenopus larvae reared in space indicated no qualitative differences in the vestibular organs, compared to ground-reared controls. A similar lack of differences in Xenopus were reported. The ultricular otolith was 30% larger in space-reared Xenopus. No differences in saccular otolith volume between centrifuged and control adult rats were found. A delay in otoconial development in chick embryos reared at 2 grams on a centrifuge was reported but in a later report, no differences in otolith weight between 2 grams and control chicks were found. Increased optokinetic responses in flight-reared Xenopus tadpoles, suggesting that the animals reared in the absence of gravity made greater relative use of their visual system, rather than the vestibular system, in orienting to a moving stimulus was reported. To test early Japanese newt, CYnops pyrrhogaster, were maintained in orbit for 15 days on the IML-2 mission in 1994. All specimens reached orbit before any otoconia were formed and all major components of the inner ear were formed by the end of the flight. In ground-based studies of he Aplysia statocyst, the volume of the statolith in embryos and the number statoconia in post-metamorphic animals were compared between 1-gram controls and specimens reared at 2 to 5.7 grams.

Wiederhold, Michael L.↗
NASA NTRS1999

NASA EPSCoR Nebraska Preparation Grant: Year 1

The UNO Aviation Institute Monograph Series began in 1994 as a key component of the education outreach and information transfer missions of the Aviation Institute and the NASA Nebraska Space Grant & EPSCOR (Experimental Program to Stimulate Competitive Research) Programs. The series is an outlet for aviation materials to be indexed and disseminated through an efficient medium. Publications are welcome in all aspects of aviation. Publication formats may include, but are not limited to, conference proceedings, bibliographies, research reports, manuals, technical reports, and other documents that should be archived and indexed for future reference by the aviation and world wide communities.

Bowen, Brent D.↗
NASA NTRS1999

High Temperature Solar Reflector, Its Preparation and Use

A coating-substrate combination having high specular reflectivity at high temperatures reaching 8000 C in a vacuum is described. The substrate comprises pure nickel metal or a nickel-containing metal alloy such as stainless steel having a highly polished reflective surface. The coating is a layer of silver deposited on the substrate to a thickness of 300 A to 3000 A. A 300 A to 5000 A protective coating of silica, alumina or magnesium fluoride is used to cover the silver and to protect it from oxidation. The combination is useful as a parabolic shaped secondary concentrator for collecting solar radiation for generating power or thermal energy for satellite uses. The reflective layer and protective coating preferably are applied to the reflective surface of the substrate by electron beam evaporation or by ion sputtering.

Jaworske, Donald A.↗
NASA NTRS1998

Preparation and Surface Analysis of a Fluorinated Amorphous Silicon for Photo-voltaic Device Application

Amorphous silicon films (a-Si:H) have been routinely deposited on a variety of substrates. Surface and interfacial studies were carried out with a PHI 5600 X-ray photo electron spectrometer. Co-deposition with fluorine yielded films having oxygen present as bulk oxide. The higher the fluorine content, the greater the amount of bulk oxygen observed. The presence of oxygen may be a contributing factor to inconsistent film properties of fluorine doped silicon materials, reported else where. A definite chemical interface between a layer containing fluorine and a layer made from pure silane has been delineated.

McWhinney, Hylton G.↗
NASA NTRS2000

Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry

Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this report we present a method for making ion exchange polymer films, which considerably simplify the solid-phase spectroscopic techniques. The polymer consists of formaldehyde-crosslinked polyvinyl alcohol with polyacrylic acid entrapped therein. The films are a carboxylate weak cation exchanger in the calcium form. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.

Hill, Carol M.↗
NASA NTRS2000

The Effects of pH on the Growth and Aspect Ratio of Chicken Egg White Lysozyme Crystals Prepared in Different Buffers

We have measured the nucleation and aspect ratio of CEWL crystals grown by vapor diffusion in acetate, butyrate, carbonate, succinate, and phosphate buffers in a range of pH spanning the pK(sub a) of these buffers. The nucleation numbers drop off significantly in the vicinity of pK(sub a) for each of the buffers except the phosphate system, in which we used only the pH range around the second titration point(pK2). There is a concomitant increase in the sizes of the crystals. Some typical nucleation number results are shown. These data support and extend other observations. In addition, we have examined changes in aspect ratio which accompany the suppression of nucleation within each buffer system. The length of the face in the [001] direction was measured, and compared to the width of the (110) face in the [110] type directions. We find that while the aspect ratio of the crystals is affected by pH, it is dominated by a correlation with the size of the crystals. Small crystals are longer in the [0011 direction than crystals that are larger (higher pH within a buffer system). This relationship is found to hold independent of the choice of buffer. These results are consistent with those of Judge et al, who used a batch process which resulted in uniform sizing of crystals at each pH. In these experiments, we specifically avoid agitating the protein/salt buffer mixture when combining the two. This permits the formation of a range of sizes at a given pH. The results for a .05 M acetate 5% NaCl buffer are also shown. We will discuss these results in light of a growth model.

Gibson, U. J.↗
NASA NTRS2000

Lessons Learned on Operating and Preparing Operations for a Technology Mission from the Perspective of the Earth Observing-1 Mission

The New Millennium Program's first Earth-observing mission (EO-1) is a technology validation mission. It is managed by the NASA Goddard Space Flight Center in Greenbelt, Maryland and is scheduled for launch in the summer of 2000. The purpose of this mission is to flight-validate revolutionary technologies that will contribute to the reduction of cost and increase of capabilities for future land imaging missions. In the EO-1 mission, there are five instrument, five spacecraft, and three supporting technologies to flight-validate during a year of operations. EO-1 operations and the accompanying ground system were intended to be simple in order to maintain low operational costs. For purposes of formulating operations, it was initially modeled as a small science mission. However, it quickly evolved into a more complex mission due to the difficulties in effectively integrating all of the validation plans of the individual technologies. As a consequence, more operational support was required to confidently complete the on-orbit validation of the new technologies. This paper will outline the issues and lessons learned applicable to future technology validation missions. Examples of some of these include the following: (1) operational complexity encountered in integrating all of the validation plans into a coherent operational plan, (2) initial desire to run single shift operations subsequently growing to 6 "around-the-clock" operations, (3) managing changes in the technologies that ultimately affected operations, (4) necessity for better team communications within the project to offset the effects of change on the Ground System Developers, Operations Engineers, Integration and Test Engineers, S/C Subsystem Engineers, and Scientists, and (5) the need for a more experienced Flight Operations Team to achieve the necessary operational flexibility. The discussion will conclude by providing several cost comparisons for developing operations from previous missions to EO-1 and discuss some details that might be done differently for future technology validation missions.

Mandl, Dan↗
NASA NTRS2000

Substrate Preparations in Epitaxial ZnO Film Growth

Epitaxial ZnO films were grown on the two polar surfaces (O-face and Zn-face) of (0001) ZnO single crystal substrates using off-axis magnetron sputtering deposition. Annealing-temperature dependence of ZnO substrates was studied. ZnO films grown on sapphire substrates have also been investigated for comparison purposes and the annealing temperature of A1203 substrates is 1000 C. Substrates and films were characterized using photoluminescence (PL) spectrum, x-ray diffraction, atomic force microscope, energy dispersive spectrum, and electric transport measurements. It has been found that the ZnO film properties were different when films were grown on the two polarity surfaces of ZnO substrates and the A1203 substrates. An interesting result shows that high temperature annealing of ZnO single crystals will improve the surface structure on the O-face surface rather than the opposite surface. The measurements of homoepitaxial ZnO films indicate that the O-terminated surface is better for ZnO epitaxial film growth.

Zhu, Shen↗