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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Evaluation of analytical methodology for hydrocarbons in high pressure air and nitrogen systems

Samples of liquid oxygen, high pressure nitrogen, low pressure nitrogen, and missile grade air were studied to determine the hydrocarbon concentrations. Concentration of the samples was achieved by adsorption on a molecular sieve and activated charcoal. The trapped hydrocarbons were then desorbed and transferred to an analytical column in a gas chromatograph. The sensitivity of the method depends on the volume of gas passed through the adsorbent tubes. The value of the method was verified through recoverability and reproducibility studies. The use of this method enables LOX, GN2, and missile grade air systems to be routinely monitored to determine low level increases in specific hydrocarbon concentration that could lead to potentially hazardous conditions.

Source record↗
NASA NTRS2013

Evidence for Perchlorates and the Origin of Chlorinated Hydrocarbons Detected by SAM at the Rocknest Aeolian Deposit in Gale Crater

A single scoop of the Rocknest aeolian deposit was sieved (less than 150 micrometers), and four separate sample portions, each with a mass of approximately 50 mg, were delivered to individual cups inside the Sample Analysis at Mars (SAM) instrument by the Mars Science Laboratory rover's sample acquisition system. The samples were analyzed separately by the SAM pyrolysis evolved gas and gas chromatograph mass spectrometer analysis modes. Several chlorinated hydrocarbons including chloromethane, dichloromethane, trichloromethane, a chloromethylpropene, and chlorobenzene were identified by SAM above background levels with abundances of approximately 0.01 to 2.3 nmol. The evolution of the chloromethanes observed during pyrolysis is coincident with the increase in O2 released from the Rocknest sample and the decomposition of a product of N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA), a chemical whose vapors were released from a derivatization cup inside SAM. The best candidate for the oxychlorine compounds in Rocknest is a hydrated calcium perchlorate (Ca(ClO4)2·nH2O), based on the temperature release of O2 that correlates with the release of the chlorinated hydrocarbons measured by SAM, although other chlorine-bearing phases are being considered. Laboratory analog experiments suggest that the reaction of Martian chlorine from perchlorate decomposition with terrestrial organic carbon from MTBSTFA during pyrolysis can explain the presence of three chloromethanes and a chloromethylpropene detected by SAM. Chlorobenzene may be attributed to reactions of Martian chlorine released during pyrolysis with terrestrial benzene or toluene derived from 2,6-diphenylphenylene oxide (Tenax) on the SAM hydrocarbon trap. At this time we do not have definitive evidence to support a nonterrestrial carbon source for these chlorinated hydrocarbons, nor do we exclude the possibility that future SAM analyses will reveal the presence of organic compounds native to the Martian regolith.

sample analysis at mars↗
NASA NTRS1983

Remote sensing techniques used in hydrocarbon exploration - A state-of-the-art review

Lintz (1972) has defined remote sensing for petroleum exploration as the detection from a distance of variations of the earth's surface or properties. Possibilities foreseen by Lintz could be realized with the Lander satellite. When used in 'phase-one' exploration programs, Landsat data have been effective in 'zeroing-in' on potential hydrocarbon traps, and later, when supplemented by more conventional exploration procedures, have led to the discovery of these resources. The present investigation is concerned with an overview of the methods utilized in 'phase-one' hydrocarbon exploration programs. The considered methods are to serve as an initial tool to aid the more conventional exploration procedures. Attention is given to visual interpretations, digital image processing, lineament analysis, surface anomalies, and geomorphology and topography.

Gonzales, R. W.↗
NASA NTRS2014

Origin of Chlorobenzene Detected by the Curiosity Rover in Yellowknife Bay: Evidence for Martian Organics in the Sheepbed Mudstone?

The Sample Analysis at Mars (SAM) instrument on the Curiosity rover is designed to determine the inventory of organic and inorganic volatiles thermally evolved from solid samples using a combination of evolved gas analysis (EGA), gas chromatography mass spectrometry (GCMS), and tunable laser spectroscopy. The first solid samples analyzed by SAM, a scoop of windblown dust and sand at Rocknest (RN), revealed chlorinated hydrocarbons derived primarily from reactions between a martian oxychlorine phase (e.g. perchlorate) and terrestrial carbon from N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) vapor present in the SAM instrument background. Chlorobenzene (CBZ) was also identified by SAM GCMS at RN at trace levels (approx.0.007 nmol) and was attributed to the reaction of chlorine with the Tenax polymers used in the hydrocarbon traps. After the RN analyses, Curiosity traveled to Yellowknife Bay and drilled two separate holes designated John Klein (JK) and Cumberland (CB). Analyses of JK and CB by both SAM and the CheMin x-ray diffraction instrument revealed a mudstone consisting of approx.20 wt% smectite clays, which on Earth are known to aid the concentration and preservation of organic matter. In addition, higher abundances and a more diverse suite of chlorinated hydrocarbons in CB compared to RN suggests that martian or meteoritic organic sources may be preserved in the mudstone. Here we discuss the SAM EGA and GCMS measurements of volatiles released from the Sheepbed mudstone. We focus primarily on the elevated CBZ detections at CB and laboratory analog experiments conducted to help determine if CBZ is derived from primarily terrestrial, martian, or a combination of sources.

origin of↗
NASA NTRS1980

Vacuum applications of metal foams

Several vacuum applications of copper foams in the density range 2-5% and pore sizes of 0.5-0.7 mm are discussed, such as a foreline hydrocarbon trap in a mechanical vacuum pump, a molecular-flow resistor, a diffuser, and a water injector. Other suggested applications include the use of foam copper in the form of an externally heated plug to remove traces of oxygen from inert gases bled into a vacuum system through a stainless steel line and the use of the porous surface for minimizing release of secondary electrons from electrodes in the path of charged particle beams.

Kendall, B. R. F.↗
NASA NTRS2012

Detecting Organic Compounds Released from Iron Oxidizing Bacteria using Sample Analysis at Mars (SAM) Like Instrument Protocols

Mars is a planet of great interest for Astrobiology since its past environmental conditions are thought to have been favourable for the emergence life. At present, the Red Planet is extremely cold and dry and the surface is exposed to intense UV and ionizing radiation, conditions generally considered to be incompatible with life as we know it on Earth. It was proposed that the shallow subsurface of Mars, where temperatures can be above freezing and liquid water can exist on rock surfaces, could harbor chemolithoautotrophic bacteria such as the iron oxidizing microorganism Pseudomonas sp. HerB. The Mars Science Laboratory (MSL) mission will provide the next opportunity to carry out in situ measurements for organic compounds of possible biological origin on Mars. One instrument onboard MSL, called the Sample Analysis at Mars (SAM) instrument suite, will carry out a broad and sensitive search for organic compounds in surface samples using either high temperature pyrolysis or chemical extraction followed by gas chromatography mass spectrometry. We present gas chromatograph mass spectrometer (GC/MS) data on crushed olivine rock powders that have been inoculated with Pseudomonas sp. HerB at different concentrations ranging from approx 10(exp 2) to 10(exp 7) cells per gram. The inoculated olivine samples were heated under helium carrier gas flow at 500 C and the pyrolysis products concentrated using a SAM-like hydrocarbon trap set at -20 C followed by trap heating and analysis by GC/Ms. In addition, the samples were also extracted using a low temperature "one-pot" chemical extraction technique using N-methyl, N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) as the silylating agent prior to GC/MS analysis. We identified several aldehydes, thiols, and alkene nitriles after pyrolysis GC/MS analysis of the bacteria that were not found in the olivine control samples that had not been inoculated with bacteria. The distribution of pyrolysis products extracted from the bacteria was clearly distinct from similar GC/MS analyses of the carbonaceous meteorite Murchison that was dominated by sulfur containing aromatic compounds. A similar comparison, if organic compounds are detected by SAM on Mars, could be useful to help discriminate between meteoritic or biological origins.

Glavin, D. P.↗
NASA NTRS1966

Fully Deuterated Aliphatic Hydrocarbons Obtained From Iron Carbide Treated with DCl and D2O

According to Oparin, Mendeleev thought that the origin of petroleum was the result of the hydrolysis of iron carbides by superheated steam under pressure from the deep interior of the Earth through geological formations where the metal carbides exist. As early as 1877, Mendeleev described the reaction leading to the synthesis of hydrocarbons according to the general equation 3Fe(sub m)C(sub n) + mH2O yields mFe3O4 + C(sub 3n)H(sub 8m). Other experimental studies on the production of hydrocarbons from cast iron have been reported. Because of the possibility that hydrocarbons may have been trapped within the carbon matrix of the cast iron, which usually has a high content of carbon, we have studied the reaction of pure iron carbide with deuterium chloride and deuterated water. This was done in order to distinguish any newly formed deuterated hydrocarbons from any possible impurities of trapped hydrocarbons. The experiments were carried out by simply allowing iron carbide to react with concentrated deuterium chloride in D2O. The volatile hydrocarbon fraction examined by gas chromatography-mass spectrometry (GC/MS), using a Finnigan 1020/OWA instrument. contained low molecular weight hydrocarbons in a range C3 to C7. Lower molecular weight hydrocarbons were not detected by GC/MS because the MS scanning mode was preset above mass 40 to exclude components of air. The identified hydrocarbons are similar to those obtained under prebiotic conditions using high frequency discharge. The hydrocarbons found in common were propane, butane, pentane, 3-methylpentane, hexane, and heptane. The percent yields decline with increasing carbon number (propane 11%, n-heptane 1%). Similar results have been obtained by the direct treatment of metal carbides by pulse laser vaporization mass spectrometry. These results show that the hydrolysis of iron carbides may have been a significant source of hydrocarbons on the primitive Earth. There appears to be a predominance of straight chain isomers, which may have been important in the prebiotic synthesis of membrane-forming compounds.

Marquez, C.↗
NASA NTRS1974

An evaluation of the suitability of ERTS data for the purposes of petroleum exploration

This experiment was designed to determine the types and amounts of information valuable to petroleum exploration extractable from ERTS data and the cost of obtaining the information using traditional or conventional means. It was desired that an evaluation of this new petroleum exploration tool be made in a geologically well known area in order to assess its usefulness in an unknown area. The Anadarko Basin lies in western Oklahoma and the panhandle of Texas. It was chosen as a test site because there is a great deal of published information available on the surface and subsurface geology of the area, and there are many known structures that act as traps for hydrocarbons. This basin is similar to several other large epicontinental sedimentary basins. It was found that ERTS imagery is an excellent tool for reconnaissance exploration of large sedimentary basins or new exploration provinces. For the first time, small and medium size oil companies can rapidly and effectively analyze exploration provinces as a whole.

Collins, R. J.↗
NASA NTRS1974

An evaluation of the suitability of ERTS data for the purposes of petroleum exploration

This investigation was undertaken to determine the types and amounts of information valuable to petroleum exploration that are extractable from ERTS data and to determine the cost of obtaining the information from ERTS relative to costs using traditional or conventional means. In particular, it was desirable to evaluate this new petroleum exploration tool in a geologically well-known area in order to assess its potential usefulness in an unknown area. In light of the current energy situation, it is felt that such an evaluation is important in order to best utilize technical efforts with customary exploration tools, by rapidly focusing attention on the most promising areas in order to reduce the time required to go through the exploration cycle and to maximize cost savings. The Anadarko Basin lies in western Oklahoma and the panhandle of Texas (Figure 1). It was chosen as a test site because there is a great deal of published information available on the surface and subsurface geology of the area, there are many known structures that act as traps for hydrocarbons, and it is similar to several other large epicontinental sedimentary basins.

Everett, J. R.↗
NASA NTRS2008

Energy Deposition Processes in Titan's Upper Atmosphere

Most of Titan's atmospheric organic and nitrogen chemistry, aerosol formation, and atmospheric loss are driven from external energy sources such as Solar UV, Saturn's magnetosphere, solar wind and galactic cosmic rays. The Solar UV tends to dominate the energy input at lower altitudes of approximately 1100 km but which can extend down to approximately 400 km, while the plasma interaction from Saturn's magnetosphere, Saturn's magnetosheath or solar wind are more important at higher altitudes of approximately 1400 km, but the heavy ion plasma [O(+)] of approximately 2 keV and energetic ions [H(+)] of approximately 30 keV or higher from Saturn's magnetosphere can penetrate below 950km. Cosmic rays with energies of greater than 1 GeV can penetrate much deeper into Titan's atmosphere with most of its energy deposited at approximately 100 km altitude. The haze layer tends to dominate between 100 km and 300 km. The induced magnetic field from Titan's interaction with the external plasma can be very complex and will tend to channel the flow of energy into Titan's upper atmosphere. Cassini observations combined with advanced hybrid simulations of the plasma interaction with Titan's upper atmosphere show significant changes in the character of the interaction with Saturn local time at Titan's orbit where the magnetosphere displays large and systematic changes with local time. The external solar wind can also drive sub-storms within the magnetosphere which can then modify the magnetospheric interaction with Titan. Another important parameter is solar zenith angle (SZA) with respect to the co-rotation direction of the magnetospheric flow. Titan's interaction can contribute to atmospheric loss via pickup ion loss, scavenging of Titan's ionospheric plasma, loss of ionospheric plasma down its induced magnetotail via an ionospheric wind, and non-thermal loss of the atmosphere via heating and sputtering induced by the bombardment of magnetospheric keV ions and electrons. This energy input evidently drives the large positive and negative ions observed below approximately 1100 km altitude with ion masses exceeding 10,000 daltons. We refer to these ions as seed particles for the aerosols observed below 300 km altitude. These seed particles can be formed, for example, from the polymerization of acetylene (C2H2) and benzene (C6H6) molecules in Titan's upper atmosphere to form polycyclic aromatic hydrocarbons (PAH) and/or fullerenes (C60). In the case of fullerenes, which are hollow spherical carbon shells, magnetospheric keV [O(+)] ions can become trapped inside the fullerenes and eventually find themselves inside the aerosols as free oxygen. The aerosols are then expected to fall to Titan's surface as polymerized hydrocarbons with trapped free oxygen where unknown surface chemistry can take place.

Sittler, Edward C., Jr.↗
NASA NTRS1985

Multistage open-tube trap for enrichment of part-per-trillion trace components of low-pressure (below 27-kPa) air samples

A multistage open-tube trap for cryogenic collection of trace components in low-pressure air samples is described. The open-tube design allows higher volumetric flow rates than densely packed glass-bead traps commonly reported and is suitable for air samples at pressures below 27 kPa with liquid nitrogen as the cryogen. Gas blends containing 200 to 2500 parts per trillion by volume each of ethane and ethene were sampled and hydrocarbons were enriched with 100 + or - 4 percent trap efficiency. The multistage design is more efficient than equal-length open-tube traps under the conditions of the measurements.

Ohara, D.↗
NASA NTRS1991

A geochemical assessment of possible lunar ore formation

The Moon apparently formed without appreciable water or other relatively volatile materials. Interior concentrations of water or other volatile substances appear to be extremely low. On Earth, water is important to the genesis of nearly all types of ores. Thus, some have reasoned that only abundant elements would occur in ore concentrations. The definition and recognition of ores on the Moon challenge the imaginations and the terrestrial perceptions of ore bodies. Lunar ores included solar-wind soaked soils, which contain abundant but dilute H, C, N, and noble gases (including He-3). Oxygen must be mined; soils contain approximately 45 percent (wt). Mainstream processes of rock formation concentrated Si, Mg, Al, Fe, and Ca, and possibly Ti and Cr. The highland surface contains approximately 70 percent (wt) feldspar (mainly CaAl2Si2O8), which can be separated from some highland soils. Small fragments of dunite were collected; dunite may occur in walls and central peaks of some craters. Theoretical extensions of observations of lunar samples suggest that the Moon may have produced ores of trace elements. Some small fragments have trace-element concentrations 10(exp 4) times higher than the lunar average, indicating that effective geochemical separations occurred; processes included fractional crystallization, silicate immiscibility, vaporization and condensation, and sulfide metamorphism. Operations of these processes acting on indigenous materials and on meteoritic material in the regolith could have produced ores. Infalling carbonaceous meteorites and comets have added water and hydrocarbons that may have been cold-trapped. Vesicles in basalts, pyroclastic beads, and reported transient events suggest gag emission from the lunar interior; such gas might concentrate and transport rare elements. Large impacts may disperse ores or produce them through deposition of heat at depth and by vaporization and subsequent condensation. The main problem in assessing lunar resources is the ignorance about the largely unexplored Moon.

Haskin, Larry A.↗
NASA NTRS2010

Selection of Environmentally Friendly Solvents for the Extravehicular Mobility Unit Secondary Oxygen Pack Cold Trap Testing

Freon-113(TradeMark) has been used as a chemistry lab sampling solvent at NASA/JSC for EMU (extravehicular Mobility Unit) SOP (Secondary Oxygen Pack) oxygen testing Cold Traps utilized at the USA (United Space Alliance) Houston facility. Similar testing has occurred at the HSWL (Hamilton Sundstrand Windsor Locks) facility. A NASA Executive Order bans the procurement of all ODS (ozone depleting substances), including Freon-113 by the end of 2009. In order to comply with NASA direction, HSWL began evaluating viable solvents to replace Freon-113 . The study and testing effort to find Freon-113 replacements used for Cold Trap sampling is the subject of this paper. Test results have shown HFE-7100 (a 3M fluorinated ether) to be an adequate replacement for Freon-113 as a solvent to remove and measure the non-volatile residue collected in a Cold Trap during oxygen testing. Furthermore, S-316 (a Horiba Instruments Inc. high molecular weight, non-ODS chlorofluorocarbon) was found to be an adequate replacement for Freon-113 as a solvent to reconstitute non-volatile residue removed from a Cold Trap during oxygen testing for subsequent HC (hydrocarbon) analysis via FTIR (Fourier Transform Infrared Spectroscopy).

Steele, John↗
NASA NTRS2000

An abiotic origin for hydrocarbons in the Allan Hills 84001 martian meteorite through cooling of magmatic and impact-generated gases

Thermodynamic calculations of metastable equilibria were used to evaluate the potential for abiotic synthesis of aliphatic and polycyclic aromatic hydrocarbons (PAHs) in the martian meteorite Allan Hills (ALH) 84001. The calculations show that PAHs and normal alkanes could form metastably from CO, CO2, and H2 below approximately 250-300 degrees C during rapid cooling of trapped magmatic or impact-generated gases. Depending on temperature, bulk composition, and oxidation-reduction conditions, PAHs and normal alkanes can form simultaneously or separately. Moreover, PAHs can form at lower H/C ratios, higher CO/CO2 ratios, and higher temperatures than normal alkanes. Dry conditions with H/C ratios less than approximately 0.01-0.001 together with high CO/CO2 ratios also favor the formation of unalkylated PAHs. The observed abundance of PAHs, their low alkylation, and a variable but high aromatic to aliphatic ratio in ALH 84001 all correspond to low H/C and high CO/CO2 ratios in magmatic and impact gases and can be used to deduce spatial variations of these ratios. Some hydrocarbons could have been formed from trapped magmatic gases, especially if the cooling was fast enough to prevent reequilibration. We propose that subsequent impact heating(s) in ALH 84001 could have led to dissociation of ferrous carbonates to yield fine-grain magnetite, formation of a CO-rich local gas phase, reduction of water vapor to H2, reequilibration of the trapped magmatic gases, aromatization of hydrocarbons formed previously, and overprinting of the synthesis from magmatic gases, if any. Rapid cooling and high-temperature quenching of CO-, H2-rich impact gases could have led to magnetite-catalyzed hydrocarbon synthesis.

Non-NASA Center↗
NASA NTRS1991

Short-period comets

The spacecraft flybys of Comet Halley in 1986 confirmed Whipple's icy conglomerate hypothesis for cometary nuclei and showed that comets are far richer in volatiles than any other class of solar system bodies. Water is the most abundant volatile, comprising roughly 80 percent of the gas flowing out from the nucleus. Carbon monoxide is next with a content of 15 percent relative to water, though with approximately half of that coming from an extended source in the cometary coma, i.e., hydrocarbon dust grains. The detection of large numbers of hydrocarbon CHON grains was one of the more significant discoveries of the Halley flybys, as was the ground-based observation that CN occurs in jets, again indicating an extended source. Evidence was also found for more complex hydrocarbons. Estimates of the total dust-to-gas ratio for Halley range as high as 2:1, indicating that a substantial fraction of the volatile material may be tied up in solid hydrocarbons rather than ices. The role of clathrates in trapping more volatile ices is not yet understood. If Halley can be taken to be representative of all short-period comets, then the short-period comets may provide a significant source of volatiles in near-earth space. This resource is more difficult to reach dynamically than the near-earth asteriods, but the high volatile content may justify the additional effort necessary. In addition, there is considerable evidence that at least some fraction of the near-earth asteriods are extinct cometary nuclei which have evolved into asteroid orbits, and which may contain significant volatiles buried beneath an insulating lag-deposit crust of nonvolatiles. Knowledge of comets will be greatly enhanced in the near future by the Comet Rendezvous Flyby mission now under development by NASA, and by the proposed Rosetta mission.

Weissman, Paul R.↗
NASA NTRS2005

NASA Tech Briefs, January 2005

Topics covered include: Fiber-Optic Sensor Would Monitor Growth of Polymer Film; Sensors for Pointing Moving Instruments Toward Each Other; Pd/CeO2/SiC Chemical Sensors; Microparticle Flow Sensor; Scattering-Type Surface-Plasmon-Resonance Biosensors; Diode-Laser-Based Spectrometer for Sensing Gases; Improved Cathode Structure for a Direct Methanol Fuel Cell; X-Band, 17-Watt Solid-State Power Amplifier; Improved Anode for a Direct Methanol Fuel Cell; Tools for Designing and Analyzing Structures; Interactive Display of Scenes with Annotations; Solving Common Mathematical Problems; Tools for Basic Statistical Analysis; Program Calculates Forces in Bolted Structural Joints; Integrated Structural Analysis and Test Program; Molybdate Coatings for Protecting Aluminum Against Corrosion; Synthesizing Diamond from Liquid Feedstock; Modifying Silicates for Better Dispersion in Nanocomposites; Powder-Collection System for Ultrasonic/Sonic Drill/Corer; Semiautomated, Reproducible Batch Processing of Soy; Hydrogen Peroxide Enhances Removal of NOx from Flue Gases; Subsurface Ice Probe; Real-Time Simulation of Aeroheating of the Hyper-X Airplane; Using Laser-Induced Incandescence To Measure Soot in Exhaust; Method of Real-Time Principal-Component Analysis; Insect-Inspired Flight Control for Unmanned Aerial Vehicles; Domain Compilation for Embedded Real-Time Planning; Semantic Metrics for Analysis of Software; Simulation of Laser Cooling and Trapping in Engineering Applications; Large Fluvial Fans and Exploration for Hydrocarbons; Doping-Induced Interband Gain in InAs/AlSb Quantum Wells; Development of Software for a Lidar-Altimeter Processor; Upgrading the Space Shuttle Caution and Warning System; and Fractal Reference Signals in Pulse-Width Modulation.

Source record↗
NASA NTRS1997

Cryptoblemes: A New Discovery with Major Economic Implications and Profound Changes to the Geologic Paradigm

Cryptoblemes are subtle impact shock signatures imprinted by cosmic debris on the crustal surfaces of lunar planetary bodes. These signatures constitute a complex cumulative overprinting of topographic, structural geophysical, and tectonic patterns that have a conspicuous radial centric multiringed symmetry. The geometry and distribution of cryptoblemes on Earth is comparable to the size and density of impact features on lunar planetary surfaces. Analysis of satellite imagery, sea-floor sonar, side-looking radar and aerial photographs of specific sites reveals new criteria for the identification and confirmation of impact-shock signatures. These criteria include joint and foliation patterns with asbestiform minerals, ribbon-quartz, spheroidal weathering, domal exfoliation, pencil shale, and shock spheres, which may originate from hydrocavitation of water-saturated sedimentary rocks. Cryptoblemes may also be associated with breccia pipes, sinkholes, buttes, mesas, and bogs, high-Rn anomalies, nodular concentrations, and earthquake epicenters. Major implications of cryptobleme identification include exploratory targeting of hydrocarbon and mineral deposits and the explanation of their origins. Analysis of known mineral deposits, structural traps and sedimentary basins show a direct correlation with cryptobleme patterns. Significant geologic paradigm shifts related to cryptoblemes include mountain building processes, structural orogenies, induced volcanism, earthquake origins, hydrocarbon diagenesis, formation mineral deposits, continental rifting, and plate movements, magnetic overprinting and local regional, and global geologic extinction and speciation patterns. Two figures provide a comparison between a multiring impact overprint in water and multiring cryptobleme in the U.S. basin range. (Additional information is contained in the original document).

Windolph, J., Jr.↗
NASA NTRS1994

Direct Monitoring of Trace Atmospheric Species via Ion Trap Mass Spectrometry

There is an ever-increasing emphasis on the part of government agencies, academia, and industry on enhancing our understanding of atmospheric processes and assessing the impact of human activities on these processes. While issues such as the ozone hole and rising levels of greenhouse gases have received major attention. relatively little is known about the types, concentrations, sources, and sinks of hydrocarbons in the troposphere and stratosphere. Such information would be of tremendous utility in assessing the roles of various anthropogenic and biogenic processes on global carbon cycles. An ion trap mass spectrometer has been developed for monitoring trace levels of hydrocarbons in the atmosphere on NASA's DC-8 "flying laboratory". This aircraft is used to provide measurements in support of a number of "Mission to Planet Earth" activities and tropospheric chemistry experiments. In past missions, specific compounds have been monitored via highly specialized instrumentation, fast GO, or collection of whole air samples for subsequent ground-based analysis. The ion trap has several features. including small size. excellent sensitivity, and broad applicability, which make it highly atttrat:ive for atmospheric monitoring. The design of this instrument, its air sampling interface. and the various complications associated with aircraft-deployment will be described. Data showing the sensitivity of the instrument for detecting hydrocarbons at mixing ratios below one part-per-billion, and the use of MS/MS for direct, on-line, real-time monitoring will be presented.

Palmer, P. T.↗