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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Investigation of the Martian environment by infrared spectroscopy on Mariner 9.

Preliminary analysis of Mariner 9 IR spectroscopic data through May 1972 shows spectral features due to carbon dioxide, water vapor, and silicate dust suspended in the atmosphere. Measurements obtained during and after the planet-wide dust storm indicate that large diurnal variations in atmospheric temperature existed up to at least 30 km. Analysis of spectral features due to the atmospheric dust provides a SiO2 content of 60 (plus or minus 10)%, implying substantial geochemical differentiation. Water vapor estimates yield abundances of 10 to 20 precipitable microns, and no water vapor was detected over the north polar region.

Hanel, R.↗
NASA NTRS1973

Cost analysis of life support systems

A methodology was developed to predict realistic relative cost of Life Support Systems (LSS) and to define areas of major cost impacts in the development cycle. Emphasis was given to tailoring the cost data for usage by program planners and designers. The equipment classifications used based on the degree of refinement were as follows: (1) Working model; (2) low-fidelity prototype; (3) high-fidelity prototype; and (4) flight-qualified system. The major advanced LSS evaluated included the following: (1) Carbon dioxide removal; (2) oxygen recovery systems; (3) water recovery systems; (4) atmosphere analysis system.

Yakut, M. M.↗
NASA NTRS1991

Composite materials: Fatigue and fracture. Vol. 3

The present volume discusses topics in the fields of matrix cracking and delamination, interlaminar fracture toughness, delamination analysis, strength and impact characteristics, and fatigue and fracture behavior. Attention is given to cooling rate effects in carbon-reinforced PEEK, the effect of porosity on flange-web corner strength, mode II delamination in toughened composites, the combined effect of matrix cracking and free edge delamination, and a 3D stress analysis of plain weave composites. Also discussed are the compression behavior of composites, damage-based notched-strength modeling, fatigue failure processes in aligned carbon-epoxy laminates, and the thermomechanical fatigue of a quasi-isotropic metal-matrix composite.

O'Brien, T. K.↗
NASA NTRS2017

Flow-Tube Reactor Experiments on the High Temperature Oxidation of Carbon Weaves

Under entry conditions carbon weaves used in thermal protection systems (TPS) decompose via oxidation. Modeling this phenomenon is challenging due to the different regimes encountered along a flight trajectory. Approaches using equilibrium chemistry may lead to over-estimated mass loss and recession at certain conditions. Concurrently, there is a shortcoming of experimental data on carbon weaves to enable development of improved models. In this work, a flow-tube test facility was used to measure the oxidation of carbon weaves at temperatures up to 1500 K. The material tested was the 3D carbon weave used for the heat shield of the NASA Adaptive Deployable Entry and Placement Technology, ADEPT. Oxidation was characterized by quantifying decomposition gases (CO and CO2), by mass measurements, and by microscale surface analysis. The current set of measurements contributes to the development of finite rate chemistry models for carbon fabrics used in woven TPS materials.

Woven TPS↗
NASA NTRS1996

Studies of the Surface Treatment and Sizing of Carbon Fiber Surfaces on the Mechanical Properties of Composites Containing Carbon Fibers

Carbon fiber reinforced composites are materials where carbon fibers are used to reinforce a matrix to produce a light and strong material with important applications in the aerospace industry. There are many aspects of the preparation of these materials that would benefit from a study which combines the research of groups involved in the production, testing and analysis of these materials, and studies of the basic surface chemistry involved. This final reports presents the results of a project that has developed a collaboration between groups in all three of the major research universities in the State of Kansas, and promises to lead to a collaborative program that covers the major aspects of composite development and application. Sherwood has provided initial fiber surface treatment and sizing together with fiber and composite surface analysis; Lease, Tomblin and Wang have worked together toward the goal of preparing pre-preg and fabrication of laminated panels; Locke has developed computational models to evaluate the effect of surface treatment (and chemistry) on mechanical properties; Lease, Tomblin and Wang have worked together to perform all necessary mechanical testing. The research has been focused on materials that would benefit the High Speed Civil Transport (HSCT) program. The group has visited Dr. Howard Maars and his colleagues at NASA Langley, and has focused their studies on the NASA requirements discussed in this meeting. An important development, requested by NASA scientists, has been the acquisition and study of K3B as a matrix material for the composites. The project has led to the successful acquisition and surface analysis of K3B, together with the successful deposition of this material onto surface oxidized carbon fibers. Mechanical testing, modelling and the construction of composite preparation equipment has been achieved during the grant period.

Sherwood, Peter M. A.↗
NASA NTRS2022

Greenhouse Gas Emission Estimations for 2016-2020 using the Sherlock Air Traffic Data Warehouse

Data and analyses are presented on the utilization of aircraft in the U.S. and the greenhouse gas emissions that they create. Commercial passenger and cargo aviation flight data, captured in the Sherlock data warehouse at NASA Ames over the five years from 2016 to 2020, is used to estimate the miles flown by major aircraft models. The estimates for aggregate annual number of flights are validated against data published by the Bureau of Transportation Statistics. The corresponding fuel usage is estimated using the International Civilian Aviation Organization (ICAO) fuel use tables and carbon dioxide emissions are calculated using a fuel-use multiplicative factor. A key conclusion of this analysis is that a small number of long-haul flights (with ranges greater than 2485 statute miles) create a disproportionately large fraction (30%) of annual total U.S. aviation-related carbon dioxide emissions, while a relatively large number of short flights (less than 311 statute miles) contribute a small net amount (less than 5%) of U.S. aviation-related carbon dioxide emissions. These U.S. results are consistent with a similar recent 2020 emissions study conducted by EUROCONTROL.

Emissions↗
NASA NTRS1976

Agglutinates and carbon accumulation in Apollo 17 lunar soils

A critical review of maturity with respect to the abundance of implanted solar wind elements (SWE) in lunar soils indicates: (1) that the Rosiwal Principle has limited applicability in determining implantation of SWE in lunar soils, and (2) that despite a depletion of SWE in agglutinitic glass, agglutinates are enriched in SWE due to the presence of buried surfaces of numerous clasts within agglutinates. A statistical analysis of published data of several Apollo 17 soils indicates that the abundance of carbon and, by analogy, the abundance of other SWE are correlatable with the agglutinate content and the mean grain size of lunar soils. Microscopic examination of more than 5000 grains of agglutinates in polished thin sections reveals a wide range of variability in the mineralogy, grain size distribution, degree of recycling, etc., of the clast population in agglutinates. This indicates that the volume-correlated SWE content of agglutinates may vary and need not be constant.

Basu, A.↗
NASA NTRS1975

Detection of carbon monoxide in Jupiter

New, ground-based, 5-micron spectra of Jupiter have revealed the presence of a trace quantity of carbon monoxide in the lower atmosphere of the planet. A preliminary analysis suggests a number mixing ratio in the neighborhood of 10 to the minus ninth power and a column abundance of roughly 5 times 10 to the 17th power molecules per sq cm to a depth of at least 2 atmospheres. It is suggested that the observation might be confirmed by microwave techniques.

Beer, R.↗
NASA NTRS1977

Research and development of a luminol-carbon monoxide flow system

Adaption of the luminol-carbon monoxide injection system to a flowing type system is reported. Analysis of actual wastewater samples was carried out and revealed that bacteria can be associated with particles greater than 10 microns in size in samples such as mixed liquor. Research into the luminol reactive oxidation state indicates that oxidized iron porphyrins, cytochrome-c in particular, produce more luminol chemiluminescence than the reduced form. Correlation exists between the extent of porphyrin oxidation and relative chemiluminescence. In addition, the porphyrin nucleus is apparently destroyed under the current chemiluminescent reaction conditions.

Thomas, R. R.↗
NASA NTRS1979

High temperature electrolytic recovery of oxygen from gaseous effluents from the carbo-chlorination of lunar anorthite and the hydrogenation of ilmenite: A theoretical study

A thermodynamic analysis discusses the compositions of gaseous effluents from the reaction of carbon and chlorine and of hydrogen with lunar anorthite and ilmenite, respectively. The computations consider the effects of the indigenous volatiles on the solid/gas reactions and on the composition of the effluent gases. A theoretical parameterization of the high temperature electrolysis of such gases is given for several types of solid ceramic electrolytes, and the effect of oxygen removal on the effluents is computed. Potential chemical interactions between the gases and the ceramic electrolytes are analyzed and discussed.

Erstfield, T. E.↗
NASA NTRS1979

Evaluation of atmospheric trace constituent sensors operating from remote space and airborne platforms

A laboratory gas analysis system was developed specifically to make trace level measurements of carbon monoxide. To assure that the data collected with this system are correctly aligned with other established methods for making these measurements, an intercalibration study was conducted. The calibration gas was analyzed by the various participating laboratories and found to contain 1.28 ppm CO. Samples were collected at 25 deg, 35 deg, and 45 deg N for profile data to study the variation in concentrations of CO and CH4 as a function of altitude and latitude in continental air over the eastern seaboard of the United States. The experiment was repeated several months later to determine if there were seasonally dependent variations in the CO and CH4 concentrations.

Condon, E.↗
NASA NTRS1989

Remote sensing of soils in the eastern Palouse region with Landsat Thematic Mapper

Soils of the Palouse region of eastern Washington State were investigated using Landsat Thematic Mapper (TM) band ratios to discriminate areas where erosion has caused paleosols to be exposed. Ratioed data were clustered and plotted to show soil lines which could be subdivided into various levels of organic matter and iron oxides. Successfully classified scenes of a summer fallow (bare soil) field were obtained with band ratios 1/4, 3/4, and 5/4 to map organic carbon and 3/4, 5/4, and 5/3 for the iron/carbon ratio indicator of erosion. Regression models were made with 5/4 data and organic carbon and 5/3 data and the iron/carbon ratio. Based on this analysis, 21 percent of the test field soils are exposed or nearly exposed paleosols.

Frazier, B. E.↗
NASA NTRS1993

IRAS variables as galactic structure tracers - Classification of the bright variables

The characteristics of the 'bright infrared variables' (BIRVs), a sample consisting of the 300 brightest stars in the IRAS Point Source Catalog with IRAS variability index VAR of 98 or greater, are investigated with the purpose of establishing which of IRAS variables are AGB stars (e.g., oxygen-rich Miras and carbon stars, as was assumed by Weinberg (1992)). Results of the analysis of optical, infrared, and microwave spectroscopy of these stars indicate that, out of 88 stars in the BIRV sample identified with cataloged variables, 86 can be classified as Miras. Results of a similar analysis performed for a color-selected sample of stars, using the color limits employed by Habing (1988) to select AGB stars, showed that, out of 52 percent of classified stars, 38 percent are non-AGB stars, including H II regions, planetary nebulae, supergiants, and young stellar objects, indicating that studies using color-selected samples are subject to misinterpretation.

Allen, L. E.↗
NASA NTRS1993

Micrometeorite pre-solar diamonds from Greenland cryoconite?

An acid-resistant residue prepared from Greenland cryoconite has been investigated to determine whether the micrometeorite component within the cryoconite contains pre-solar material analogous to that found in primitive chondritic meteorites. The residue has been analyzed for carbon content and stable isotopic comparison, by electron probe micro-analysis (EPMA) for major element chemistry and then by a combination of X-ray diffraction (XRD) and transmission electron microscopy (TEM) to elucidate the structure of any constituent mineral phases. The cryoconite sample, which was collected ca. 25 km inland of the ice margin at the latitude of Sondre Stromfjord on the west coast of Greenland, was processed following procedures used on bulk meteorite samples for the isolation of pre-solar dust components.

Yates, P. D.↗
NASA NTRS1997

Creep and Rupture Strength of an Advanced CVD SiC Fiber

In the as-produced condition the room temperature strength (approx. 6 GPa) of Textron Specialty Materials' 50 microns CVD SiC fiber represents the highest value thus far obtained for commercially produced polycrystalline SiC fibers. To understand whether this strength can be maintained after composite processing conditions, high temperature studies were performed on the effects of time, stress, and environment on 1400 deg. C tensile creep strain and stress rupture on as-produced, chemically vapor deposited SiC fibers. Creep strain results were consistent, allowing an evaluation of time and stress effects. Test environment had no influence on creep strain but I hour annealing at 1600 deg. C in argon gas significantly reduced the total creep strain and increased the stress dependence. This is attributed to changes in the free carbon morphology and its distribution within the CVD SiC fiber. For the as-produced and annealed fibers, strength at 1400 deg. C was found to decrease from a fast fracture value of 2 GPa to a 100-hr rupture strength value of 0. 8 GPa. In addition a loss of fast fracture strength from 6 GPa is attributed to thermally induced changes in the outer carbon coating and microstructure. Scatter in rupture times made a definitive analysis of environmental and annealing effects on creep strength difficult.

Goldsby, J. C.↗
NASA NTRS2004

Fuel Flexible Gas Turbine Combustor Flametube Facility Upgraded

In fiscal year 2003, test cell 23 of the Research Combustion Laboratory (RCL 23) at the NASA Glenn Research Center was upgraded with the addition of gaseous hydrogen as a working propellant and the addition of a 450-psig air-supply system. Test flexibility was further enhanced by upgrades to the facility control systems. RCL 23 can now test with gaseous hydrogen flow rates up to 0.05 lbm/sec and jet fuel flow rates up to 0.62 lbm/sec. Research airflow rates up to 3 lbm/sec are possible with the 450-psig supply system over a range of inlet temperatures. Nonvitiated, heated air is supplied from a shell and tube heat exchanger. The maximum nonvitiated facility air temperature is 1100 F at 1.5 lbm/sec. Research-section exhaust temperatures are limited to 3200 F because of material and cooling capacity limits. A variety of support systems are available depending on the research hardware configuration. Test section ignition can be provided via either a hydrogen air torch system or an electronic spark system. Emissions measurements are obtained with either pneumatically or electromechanically actuated gas sample probes, and the electromechanical system allows for radial measurements at a user-specified axial location for measurement of emissions profiles. Gas analysis data can be obtained for a variety of species, including carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NO and NOx), oxygen (O2), unburnt hydrocarbons, and unburnt hydrogen. Facility control is accomplished with a programmable logic control system. Facility operations have been upgraded to a system based on graphical user interface control screens. A data system is available for real-time acquisition and monitoring of both measurements in engineering units and performance calculations. The upgrades have made RCL 23 a highly flexible facility for research into low emissions gas turbine combustor concepts, and the flame tube configuration inherently allows for a variety of fuel nozzle configurations to be tested in a cost-effective manner. RCL 23 is poised to be a leading facility for developing modern low-emission fuel nozzles for use with jet fuel and alternative fuels.

Little, James E.↗
NASA NTRS2006

High Misalignment Carbon Seals for the Fan Drive Gear System Technologies

Aircraft engines of the future will require capability bearing compartment seals than found in current engines. Geared systems driving the fan will be subjected to inertia and gyroscopic forces resulting in extremely high angular and radial misalignments. Because of the high misalignment levels, compartment seals capable of accommodating angularities and eccentricities are required. Pratt & Whitney and Stein Seal Company selected the segmented circumferential carbon seal as the best candidate to operate at highly misaligned conditions. Initial seal tests established the misalignment limits of the current technology circumferential seal. From these results a more compliant seal configuration was conceived, designed, fabricated, and tested. Further improvements to the design are underway and plans are to conduct a durability test of the next phase configuration. A technical approach is presented, including design modification to a "baseline"seal, carbon grade selection, test rig configuration, test plan and results of analysis of seal testing.

Shaughnessy, Dennis↗