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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Impact sensitivity of materials in contact with liquid and gaseous oxygen at high pressures.

An apparatus developed by Marshall Space Flight Center for use in determining the impact sensitivity of engineering materials in liquid and gaseous oxygen at pressures greater than one atmosphere is described. This apparatus uses the impact tester described in ASTM D2512, ?Compatibility of Materials with Liquid Oxygen,' with the addition of a pressurized sample holder in place of the D2512 anvil region.

Key, C. F.↗
NASA NTRS1972

Molecular beam simulation of planetary atmospheric entry - Some recent results.

Progress is reported in the development of molecular beam techniques to simulate entry into planetary atmospheres. Molecular beam sources for producing fast beams containing CO2 and atomic oxygen are discussed. Results pertinent to the design and calibration of a mass spectrometer ion source for measurement of the Martian atmosphere during the free molecule portion of the entry trajectory are also presented. The shortcomings and advantages of this simulation technique are discussed, and it is demonstrated that even with certain inadequacies much information useful to the ion source design was obtained. Particularly, it is shown that an open-cavity configuration retains sensitivity to atomic oxygen, provides reasonable signal enhancement from the stagnation effect, is not highly sensitive to pitch and yaw effects, and presents no unforeseen problems in measuring CO2 or atomic oxygen.

French, J. B.↗
NASA NTRS2007

Portable Unit for Metabolic Analysis

The Portable Unit for Metabolic Analysis (PUMA) is an instrument that measures several quantities indicative of human metabolic function. Specifically, this instrument makes time-resolved measurements of temperature, pressure, flow, and the partial pressures of oxygen and carbon dioxide in breath during both inhalation and exhalation. Portable instruments for measuring these quantities have been commercially available, but the response times of those instruments are too long to enable temporal resolution of phenomena on the time scales of human respiration cycles. In contrast, the response time of the PUMA is significantly shorter than characteristic times of human respiration phenomena, making it possible to analyze varying metabolic parameters, not only on sequential breath cycles but also at successive phases of inhalation and exhalation within the same breath cycle. In operation, the PUMA is positioned to sample breath near the subject s mouth. Commercial off-the-shelf sensors are used for three of the measurements: a miniature pressure transducer for pressure, a thermistor for temperature, and an ultrasonic sensor for flow. Sensors developed at Glenn Research Center are used for measuring the partial pressures of oxygen and carbon dioxide: The carbon dioxide sensor exploits the relatively strong absorption of infrared light by carbon dioxide. Light from an infrared source passes through the stream of inhaled or exhaled gas and is focused on an infrared- sensitive photodetector. The oxygen sensor exploits the effect of oxygen in quenching the fluorescence of ruthenium-doped organic molecules in a dye on the tip of an optical fiber. A blue laser diode is used to excite the fluorescence, and the optical fiber carries the fluorescent light to a photodiode, the temporal variation of the output of which bears a known relationship with the rate of quenching of fluorescence and, hence, with the partial pressure of oxygen. The outputs of the sensors are digitized, preprocessed by a small onboard computer, and then sent wirelessly to a desktop computer, where the collected data are analyzed and displayed. In addition to the raw data on temperature, pressure, flow, and mole fractions of oxygen and carbon dioxide, the display can include volumetric oxygen consumption, volumetric carbon dioxide production, respiratory equivalent ratio, and volumetric flow rate of exhaled gas.

Dietrich, Daniel L.↗
NASA NTRS1983

Chemical and physical studies of type 3 chondrites. II Thermoluminescence of sixteen type 3 ordinary chondrites and relationships with oxygen isotopes

Thermoluminescence (TL) sensitivity values for sixteen type 3 ordinary chondrites, fourteen of them from Antarctica, have been measured. The values obtained (normalized to the TL sensitivity of the Dhajala meteorite) range from 1.6 (Allan Hills A77216) to 0.010 (Allan Hills A77176), and include two (Reckling Peak A80207 and Allan Hills A77176) that are particularly low. They fill a hiatus in the TL distribution that previously existed between St. Mary's County and Bishunpur, the latter being a meteorite with one of the lowest TL sensitivities known. The histogram of TL sensitivity values now shows a single distribution with higher values preferred; it resembles the histogram for L chondrites occupying the petrologic types 3, 4, 5, and 6. There is a tendency for the TL sensitivity of meteorites to decrease as delta O-18 increases. Theoretically, it is possible that the range of delta O-18 values observed may reflect progressive loss of O in the form of CO at very low temperatures, but very restrictive physical conditions and a complex history seem to be required.

Sears, D. W. G.↗
NASA NTRS2016

Utilization of O4 Slant Column Density to Derive Aerosol Layer Height from a Space-Borne UV-Visible Hyperspectral Sensor: Sensitivity and Case Study

The sensitivities of oxygen-dimer (O4) slant column densities (SCDs) to changes in aerosol layer height are investigated using the simulated radiances by a radiative transfer model, the linearized pseudo-spherical vector discrete ordinate radiative transfer (VLIDORT), and the differential optical absorption spectroscopy (DOAS) technique. The sensitivities of the O4 index (O4I), which is defined as dividing O4 SCD by 10(sup 40) molecules (sup 2) per centimeters(sup -5), to aerosol types and optical properties are also evaluated and compared. Among the O4 absorption bands at 340, 360, 380, and 477 nanometers, the O4 absorption band at 477 nanometers is found to be the most suitable to retrieve the aerosol effective height. However, the O4I at 477 nanometers is significantly influenced not only by the aerosol layer effective height but also by aerosol vertical profiles, optical properties including single scattering albedo (SSA), aerosol optical depth (AOD), particle size, and surface albedo. Overall, the error of the retrieved aerosol effective height is estimated to be 1276, 846, and 739 meters for dust, non-absorbing, and absorbing aerosol, respectively, assuming knowledge on the aerosol vertical distribution shape. Using radiance data from the Ozone Monitoring Instrument (OMI), a new algorithm is developed to derive the aerosol effective height over East Asia after the determination of the aerosol type and AOD from the MODerate resolution Imaging Spectroradiometer (MODIS). About 80 percent of retrieved aerosol effective heights are within the error range of 1 kilometer compared to those obtained from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements on thick aerosol layer cases.

Air Pollution↗
NASA NTRS1963

KNOCK REACTION

Reaction in a rapid compression apparatus was followed by pressure recording, by photography, and by sampling and chemical analysis. It was possible to investigate the highly sensitive hydrogen-oxygen reaction with this equipment. Results obtained with this reaction make it highly improbable that any hot-point effects are present, Detailed results are presented for single or two-stage ignition of hydrocarbons with air.

Hydrocarbon fuel↗
NASA NTRS1984

Space Processing Workshop

Gravitational effects on electrodeposition were studied on the KC-135 aircraft parabolic flight paths. An experiment to investigate the effect of the hyperthermal atomic oxygen atmosphere on sensitive surfaces was flown on Space Shuttle Flight STS-18. A participant list and schedule for the Fluids Experiment System (FES) Workshop are given.

Source record↗
NASA NTRS1996

Development of Y-Ba-Cu-O Superconductors for Magnetic Bearings

The material requirements, material manufacturing and magnetic properties that are relevant to fabrication of High Temperature Superconductor (HTS) magnetic bearings have been discussed. It is found that the seeded-melt-texturing method can be used to fabricate the single domain material that is required to achieve the best magnetic properties. Trapped-field mapping has been used as a non-destructive tool to determine the single-domain nature of the HTS material and quantity of the HTS disks. Both the trapped field and the levitation force of the Y-Ba-Cu-O disks are found to be strongly sensitive to the oxygen content.

Selvamanickam, V.↗
NASA NTRS1997

Quantitative Measurement of Oxygen in Microgravity Combustion

A low-gravity environment, in space or in ground-based facilities such as drop towers, provides a unique setting for studying combustion mechanisms. Understanding the physical phenomena controlling the ignition and spread of flames in microgravity has importance for space safety as well as for better characterization of dynamical and chemical combustion processes which are normally masked by buoyancy and other gravity-related effects. Due to restrictions associated with performing measurements in reduced gravity, diagnostic methods which have been applied to microgravity combustion studies have generally been limited to capture of flame emissions on film or video, laser Schlieren imaging and (intrusive) temperature measurements using thermocouples. Given the development of detailed theoretical models, more sophisticated diagnostic methods are needed to provide the kind of quantitative data necessary to characterize the properties of microgravity combustion processes as well as provide accurate feedback to improve the predictive capabilities of the models. When the demands of space flight are considered, the need for improved diagnostic systems which are rugged, compact, reliable, and operate at low power becomes apparent. The objective of this research is twofold. First, we want to develop a better understanding of the relative roles of diffusion and reaction of oxygen in microgravity combustion. As the primary oxidizer species, oxygen plays a major role in controlling the observed properties of flames, including flame front speed (in solid or liquid flames), extinguishment characteristics, flame size and flame temperature. The second objective is to develop better diagnostics based on diode laser absorption which can be of real value in both microgravity combustion research and as a sensor on-board Spacelab as either an air quality monitor or as part of a fire detection system. In our prior microgravity work, an eight line-of-sight fiber optic system measured water vapor mole fractions in the NASA Lewis 2.2-sec Drop Tower. In that system, the laser and all electronics resided at the top of the drop tower and was connected via a fiber optic cable to the rig, on which a 'pitch and catch' set of fiber collimating lenses were used to transmit the laser beam across a jet diffusion flame. This system required eight independent detection/demodulation units and had poor spatial resolution. This research builds on this earlier work, resulting in an improved capability for quantitative, nonintrusive measurement of major combustion species. A vertical cavity surface-emitting diode laser (VCSEL) and a continuous spatial scanning method permit the measurement of temporal and spatial profiles of the concentrations and temperatures of molecular oxygen. High detection sensitivity is achieved with wavelength modulation spectroscopy (WMS). One-g experiments are performed using a slot diffusion flame. Microgravity measurements on a solid fuel (cellulose sheet) system are planned for the NASA Lewis 2.2-second Drop Tower Facility.

Silver, Joel A.↗
NASA NTRS1999

Global Observations of Aerosols and Clouds from Combined Lidar and Passive Instruments to Improve Radiation Budget and Climate Studies

Current uncertainties in the effects of clouds and aerosols on the Earth radiation budget limit our understanding of the climate system and the potential for global climate change. Pathfinder Instruments for Cloud and Aerosol Spaceborne Observations - Climatologie Etendue des Nuages et des Aerosols (PICASSO-CENA) is a recently approved satellite mission within NASA's Earth System Science Pathfinder (ESSP) program which will address these uncertainties with a unique suite of active and passive instruments. The Lidar In-space Technology Experiment (LITE) demonstrated the potential benefits of space lidar for studies of clouds and aerosols. PICASSO-CENA builds on this experience with a payload consisting of a two-wavelength polarization-sensitive lidar, an oxygen A-band spectrometer (ABS), an imaging infrared radiometer (IIR), and a wide field camera (WFC). Data from these instruments will be used to measure the vertical distributions of aerosols and clouds in the atmosphere, as well as optical and physical properties of aerosols and clouds which influence the Earth radiation budget. PICASSO-CENA will be flown in formation with the PM satellite of the NASA Earth Observing System (EOS) to provide a comprehensive suite of coincident measurements of atmospheric state, aerosol and cloud optical properties, and radiative fluxes. The mission will address critical uncertainties iin the direct radiative forcing of aerosols and clouds as well as aerosol influences on cloud radiative properties and cloud-climate radiation feedbacks. PICASSO-CENA is planned for a three year mission, with a launch in early 2003. PICASSO-CENA is being developed within the framework of a collaboration between NASA and CNES.

Winker, David M.↗
NASA NTRS2000

Hydrogen Fluxes from Photosynthetic Communities: Implications for Early Earth Biogeochemistry

More than half the history of life on Earth was dominated by photosynthetic microbial mats, which must have represented the preeminent biological influence on global geochemical cycling during that time. In modem analogs of then ancient communities, hypersaline microbial mats from Guerrero Negro, Mexico, we have observed a large flux of molecular hydrogen originating in the cyanobacteria-dominated surface layers. Hydrogen production follows a distinct diel pattern and is sensitive to both oxygen tension and microbial species composition within the mat. On an early Earth dominated by microbial mats, the observed H2 fluxes would scale to global levels far in excess of geothermal emissions. A hydrogen flux of this magnitude represents a profound transmission of reducing power from oxygenic photosynthesis, both to the anaerobic biosphere, where H2 is an almost universally-utilized substrate and regulator of microbial redox chemistry, and to the atmosphere, where subsequent escape to space could provide an important mechanism for the net oxidation of Earth's surface.

Hoehler, Tori M.↗
NASA NTRS2003

Capabilities of the Materials Contamination Team at Marshall Space Flight Center

The Materials Contamination Team of the Environmental Effects Group, Materials, Processes, and Manufacturing Department, has been recognized for its contribution to space flight, including space transportation, space science and flight projects, such as the reusable solid rocket motor, Chandra X-Ray Observatory, and the International Space Station. The Materials Contamination Team s realm of responsibility encompasses all phases of hardware development including design, manufacturing, assembly, test, transportation, launch-site processing, on-orbit exposure, return, and refurbishment if required. Contamination is a concern in the Space Shuttle with sensitivity bondlines and reactive fluid (liquid oxygen) compatibility as well as for sensitive optics, particularly spacecraft such as Hubble Space Telescope and Chandra X-Ray Observatory. The Materials Contamination Team has a variety of facilities and instrumentation capable of contaminant detection identification, and monitoring. The team addresses material applications dealing with environments, including production facilities, clean rooms, and on-orbit exposure. The team of engineers and technicians also develop and evaluates new surface cleanliness inspection technologies. Databases are maintained by the team for proces! materials as well as outgassing and optical compatibility test results for specific environments.

Burns, H. D.↗
NASA NTRS2021

Anaerobic Expression and Purification of Holo-CCIS, an Artificial Iron-sulfur Protein

Iron-sulfur proteins are ubiquitous among all living organisms and are indispensable for almost all metabolic pathways ranging from photosynthesis, respiration, nitrogen, and carbon dioxide cycles. The iron-sulfur clusters primarily serve as electron acceptors and donors and transfer electrons to active sites of various enzymes, thus driving the energy metabolism. Prokaryotes like E. coli have ISC and SUF pathways that help in the assembly and maturation of iron-sulfur proteins. These ironsulfur proteins, especially with [4Fe-4S] clusters, are highly sensitive to molecular oxygen, and it would be advantageous if the de novo proteins and native proteins having iron-sulfur binding sites are expressed and isolated under anaerobic conditions. Bacterially assembled iron-sulfur proteins, when isolated and purified anaerobically, exhibit improved biochemical and biophysical stabilities in comparison to the counterparts expressed and purified aerobically and reconstituted under anaerobic conditions. This protocol outlines the expression and purification of the artificial protein, Coiled-Coil IronSulfur (CCIS). It may be deployed to both natural and artificial [4Fe-4S] proteins when heterologously expressed in E. coli.

Bhanu P. Jagilinki↗
NASA NTRS1972

Impact sensitivity of materials in contact with liquid and gaseous oxygen at high pressure

As a result of the Apollo 13 incident, increased emphasis is being placed on materials compatibility in a high pressure GOX environment. It is known that in addition to impact sensitivity of materials, approximately adiabatic compression conditions can contrive to induce materials reactivity. Test runs at high pressure using the ABMA tester indicate the following: (1) The materials used in the tests showed an inverse relationship between thickness and impact sensitivity. (2) Several materials tested exhibited greater impact sensitivity in GOX than in LOX. (3) The impact sensitivity of the materials tested in GOX, at the pressures tested, showed enhanced impact sensitivity with higher pressure. (4) The rank ordering of the materials tested in LOX up to 1000 psia is the same as the rank ordering resulting from tests in LOX at 14.7 psia.

Schwinghamer, R. J.↗
NASA NTRS1995

Measuring Traces Of Oxygen By Resonant Electron Attachment

Method of detecting trace amounts of oxygen based on dissociative attachment of electrons to oxygen molecules followed by measurement of resulting flux of negative oxygen ions in mass spectrometer. High sensitivity achieved in method by exploiting resonance in dissociative attachment of electrons to oxygen molecules: electron-attachment cross section rises to high peak at incident electron kinetic energy of 6.2 eV. Relative concentrations below 1 ppb detected. Devised to increase sensitivity of detection of oxygen in processing chambers in which oxygen regarded as contaminant; for example, chambers used in making semiconductor devices and in growing high-purity crystals.

Man, Kin Fung↗
NASA NTRS1974

Results obtained with position sensitive multiwire proportional chambers with helium, carbon, and oxygen nuclei

Spatial resolution performance results obtained at the Lawrence Radiation Laboratory Bevatron with prototype multiwire proportional chamber spatial detectors with integral delay line readout are presented. The effects due to incident nuclei charge, chamber operating parameters, chamber design, electronics, gas mixtures, and magnetic field presence have been investigated and are discussed.

Emming, J. G.↗