Remote sensing of ground and surface water contamination by leachate from landfill
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Sangrey, D. A.↗
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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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Shock tube study of ionization rates of NaCl-contaminated argon
Spectrally resolved radiometry and a microwave technique were used to measure the electron density, electron temperature, and concentration, and the concentration of sodium atoms in the weakly ionized region behind a shock wave in an argon shock tube. It is shown that the observed increase in the ionization rate is due to electron detachment of negative chlorine ions produced from sodium chloride vapor contained as an impurity in the argon gas. The observed behavior of the electron temperature in time and the reactions controlled by the electron temperature are analyzed in the light of the impurity reaction scheme.
Scheneider, C.-P.↗
Optical effect of the contamination of infrared windows by the outgassing of materials in outer space
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Silberman, E.↗
Dust-contamination monitor
Compact instrument gives instantaneous reading of accumulation of small particles on glass plate. Instrument is sensitive to particles as small as one hundred microns and should be adaptable to monitoring particulate air pollution or dust levels in semiconductor clean rooms. Dual collimated light sources produce highly monochromatic radiation direct at grazing single angle onto glass plate.
Claysmith, C. R.↗
Chemical Analysis of Outgassing Contaminants on Spacecraft Surfaces
Samples of S-13 paint on aluminum, reflection grating anomalies as affected by dielectric coatings, and rocket effluents were analyzed along with Skylab window scrapings and a gas activated semiconductor. Development of an HCl detector is also discussed. Results are briefly summarized.
Mcnutt, R. C.↗
An equation that describes material outgassing for contamination modeling
A generalization of the Clausius-Claperon equation for vapor pressure is made for an outgassing material. The expression is derived using Langmuir's equation for the outgassing rate of a material and using an empirical equation for the vapor pressure of a material as a function of its molecular weight and temperature. Also, outgassing rate equations are derived in terms of the vapor pressure of the outgassing material for three general geometries.
Heslin, T. M.↗
Removal of contaminant gases from an electrolytic urine pretreatment process
The effluent gas stream from an electrolytic urine pretreatment process was analyzed by gas chromatography-mass spectroscopy and wet chemical methods to determine its composition. The major constituents were identified as: hydrogen, carbon dioxide, oxygen, nitrogen, water vapor, and chlorine. The trace impurities were chlorinated light hydrocarbons, and a number of other organic impurities in the low ppm range. Several methods of removing all of the undesirable gases to levels acceptable for return to a space cabin atmosphere were investigated experimentally. A subsystem concept comprised of the following sequential unit processes and operations was successfully demonstrated: (1) raw urine scrubbing, (2) silica gel sorption, (3) dilution with cabin air, and (4) catalytic oxidation.
Colombo, G. V.↗
Shuttle/payload contamination evaluation (SPACE) program: User's manual
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Bareiss, L. E.↗
Puncture discharges in surface dielectrics as contaminant sources in spacecraft environments
Spacecraft in geosynchronous orbits are known to become charged to large negative potentials during the local midnight region of the satellite orbit. Such discharges have been studied by the electron beam irradiation of dielectric samples in a vacuum environment. In addition to static measurements and photographic examination of the puncture discharges in Teflon samples, the transient characteristics of the electrical discharges are determined from oscillographs of voltage and current and by charged particle measurements employing a biased Faraday cup and a retarding potential analyzer. Using these latter techniques, studies of angular and energy distributions of charged particles have indicated an initial burst of high energy electrons (5 x 10 to the 13th power per discharge at energies greater than 300 eV) followed by a less intense burst of lower energy negative particles. Positive ions are emitted from the discharge site in an initial high velocity burst followed by a lower velocity burst tentatively identified as carbon.
Yadlowsky, E. J.↗
A precision measurement of the X-ray polarization of the Crab Nebula without pulsar contamination
The linear X-ray polarization of the Crab Nebula has been precisely measured at 2.6 keV and 5.2 keV with the OSO 8 graphite crystal polarimeters. The 1.4 ms time resolution of these instruments permitted the removal of any contribution to the polarization from the pulsar. The nebular polarization is 19.2% plus or minus 1.0% at a position angle of 156.4 plus or minus 1.4 deg at 2.6 keV. At 5.2 keV the corresponding results are 19.5% plus or minus 2.8% at 152.6 plus or minus 4.0 deg.
Weisskopf, M. C.↗
NASA Charging Analyzer Program - A computer tool that can evaluate electrostatic contamination
The data from the ATS-5 and -6 Auroral Particles Experiments have shown that the environment at geosynchronous orbit can charge spacecraft surfaces to appreciable negative values. Such surface charges could have undesirable effects on satellite equipment and the data obtained in satellite experiments. A computer program, the NASA Charging Analyzer Program (NASCAP), has, in this connection, been developed to determine the surface charging of spacecraft when encountering geomagnetic substorm conditions. Once a model of a spacecraft has been developed in the NASCAP code, the surface charging can be computed for any environmental input flux. On the basis of the obtained information regarding the surface charging, charged particle trajectories can be computed to determine if it is possible for a particle to return to a satellite surface. It is pointed out that the computer runs conducted with the NASCAP code represent the first attempts to use a self-consistent program to study the behavior of spacecraft surfaces experiencing a geomagnetic substorm condition.
Stevens, N. J.↗
Ozone Contamination in Aircraft Cabins
The problem and solution to the physical ozone irritation caused by ozone concentrations in the cabin of high-altitude aircraft are presented.
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Ozone Contamination in Aircraft Cabins: Summary of recommendations
Recommendations from the three panels on in-flight measurements, flight planning to avoid high ozone, and ozone destruction techniques are summarized.
Perkins, P. J.↗
Ozone Contamination in Aircraft Cabins: Post workshop review of recommendations
The recommendations, level of priority for accomplishment, and recommended approaches and responsibility for implementation as established by the review are presented.
Perkins, P. J.↗
Ozone Contamination in Aircraft Cabins. Appendix A: Ozone toxicity
The recommendation that at various altitudes the amount of air with which ozone has mixed changes, thus changing the volume per volume relationship is discussed. The biological effects of ozone on human health and the amount of ozone necessary to produce symptoms were investigated.
Melton, C. E.↗
Ozone Contamination in Aircraft Cabins. Appendix B: Overview papers. In-flight measurements
The NASA Global Atmospheric Sampling Program ozone measurements were obtained to establish to characteristics of the ambient ozone concentration during routine operations and to determine the attenuation of ambient concentrations of cabin air systems from simultaneous ambient and in cabin measurements. The characteristics of ambient ozone include: (1) maximum concentration; (2) duration of ozone encounters; (3) frequency of ozone during a flight; (4) variability of ozone during a flight; (5) in relation to routes, altitude, and meteorological conditions.
Perkins, P. J.↗
Ozone Contamination in Aircraft Cabins. Appendix B: Overview papers. Flight 8 planning to avoid high ozone
The problem of preventing cabin ozone from exceeding a given standard was investigated. Statistical analysis of vertical distribution of ozone is summarized. The cost, logistics, maintenance, ability to forecast ozone, and avoiding high ozone concentrations are presented. Filtering approaches and the requirements to remove ozone toxicity are discussed.
Belmont, A. D.↗
Lonar crater glasses and high-magnesium australites - Trace element volatilization and meteoritic contamination
Radiochemical neutron activation analysis was used to detect six siderophile elements (Ni, Re, Os, Pd, Ir and Au) and three volatile elements (Zn, Se and Cd) in two basalts, a pumice and three impact glasses from Lonar crater, India, and in six high-magnesium australites. Significant depletions in Re and Se with respect to the parent basalts were found in the Lonar glasses. These depletions, apparently correlated with the degree of shock, are probably due to volatilization under the oxidizing conditions characteristic of earth. One of the australites is substantially enriched in siderophiles relative to the level of these elements in the other five tektites. The element patterns in the australites resemble those of the carbonaceous or cometary component of an Apollo 16 soil.
Morgan, J. W.↗