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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

The Preparation and Structural Characterization of Three Structural Types of Gallium Compounds Derived from Gallium (II) Chloride

The three compounds Ga2Cl4(4-mepy)2 (1),[GaCl2(4-mepy)4]GaCl4x1/2(4-mepy); (2) and GaCl2(4-mepy)2(S2CNEt2); (3) (4-mepy= 4-methylpyridine) have been prepared from reactions of gallium (II) chloride in 4-methylpyridine and characterized by single-crystal X-ray analysis. Small variations in the reaction conditions for gallium(II) chloride can produce crystals with substantially different structural properties. The three compounds described here encompass a neutral gallium(II) dimer in which each gallium is four-coordinate, an ionic compound containing both anionic and cationic gallium complex ions with different coordination numbers and a neutral six-coordinate heteroleptic

Gordon, Edward M.↗
NASA NTRS2000

Catalyst for Oxidation of Volatile Organic Compounds

Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

Wood, George M.↗
NASA NTRS2001

Lifetime of a Chemically Bound Helium Compound

The rare-gas atoms are chemically inert, to an extent unique among all elements. This is due to the stable electronic structure of the atoms. Stable molecules with chemically bound rare-gas atoms are, however, known. A first such compound, XePtF6, W2S prepared in 1962 and since then a range of molecules containing radon, xenon and krypton have been obtained. Most recently, a first stable chemically bound compound of argon was prepared, leaving neon and helium as the only elements for which stable chemically bound molecules are not yet known. Electronic structure calculations predict that a metastable species HHeF exists, but significance of the result depends on the unknown lifetime. Here we report quantum dynamics calculations of the lifetime of HHeF, using accurate interactions computed from electronic structure theory. HHeF is shown to disintegrate by tunneling through energy barriers into He + HF and H + He + F the first channel greatly dominating. The lifetime of HHeF is more than 120 picoseconds, that of DHeF is 14 nanoseconds. The relatively long lifetimes are encouraging for the preparation prospects of this first chemically bound helium compound.

Chaban, Galina M.↗
NASA NTRS1947

Knock-Limited Power Outputs from a CFR Engine Using Internal Coolants: Four Alkyl Amines, Three Alkanolamines, Six Amides, and Eight Heterocyclic Compounds - 3

An investigation of the antiknock effectiveness of various additive-water solutions when used as internal coolants has been conducted at the NACA Cleveland laboratory. Nine compounds have been previously run in a CFR engine and the results are presented. In an effort to find a good anti-knock-coolant additive with more desirable physical properties than those of the nine compounds previously investigated, water solutions of four alkyl amines, three alkanolamines, six amides, and eight heterocyclic compounds were investigated and the results are presented.

Imming, Harry S.↗
NASA NTRS2004

Analysis of Organic Compounds in Mars Analog Samples

The detailed characterization of organic compounds that might be preserved in rocks, ices, or sedimentary layers on Mars would be a significant step toward resolving the question of the habitability and potential for life on that planet. The fact that the Viking gas chromatograph mass spectrometer (GCMS) did not detect organic compounds should not discourage further investigations since (a) an oxidizing environment in the near surface fines analyzed by Viking is likely to have destroyed many reduced carbon species; (b) there are classes of refractory or partially oxidized species such as carboxylic acids that would not have been detected by the Viking GCMS; and (c) the Viking landing sites are not representative of Mars overall. These factors motivate the development of advanced in situ analytical protocols to carry out a comprehensive survey of organic compounds in martian regolith, ices, and rocks. We combine pyrolysis GCMS for analysis of volatile species, chemical derivatization for transformation of less volatile organics, and laser desorption mass spectrometry (LDMS) for analysis of elements and more refractory, higher-mass organics. To evaluate this approach and enable a comparison with other measurement techniques we analyze organics in Mars simulant samples.

Mahaffy, P. R.↗
NASA NTRS1987

Racemization and the origin of optically active organic compounds in living organisms

The organic compounds synthesized in prebiotic experiments are racemic mixtures. A number of proposals have been offered to explain how asymmetric organic compounds formed on the Earth before life arose, with the influence of chiral weak nuclear interactions being the most frequent proposal. This and other proposed asymmetric syntheses give only sight enantiomeric excess and any slight excess will be degraded by racemization. This applies particularly to amino acids where half-lives of 10(5)-10(6) years are to be expected at temperatures characteristic of the Earth's surface. Since the generation of chiral molecules could not have been a significant process under geological conditions, the origins of this asymmetry must have occurred at the time of the origin of life or shortly thereafter. It is possible that the compounds in the first living organisms were prochiral rather than chiral; this is unlikely for amino acids, but it is possible for the monomers of RNA-like molecules.

NASA Discipline Exobiology↗
NASA NTRS2001

Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials

The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP.

NASA Discipline Developmental Biology↗
NASA NTRS2004

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

NASA Center KSC↗
NASA NTRS2004

Non-Additive Voltametric Currents From a Mixture of Two, Three and Four Redox-Active Compounds and Electroanalytical Implications

We have published recently the effect of dissimilar diffusion coefficients on the size of the voltammetric waves from a mixture of two redox-active compounds. Similarly, at the potential range where three redox-active species, decamethylferrocene (dMeFc), ferrocene (Fc) and N-methylphenothiazine (MePTZ), are oxidized simultaneously with rates controlled by linear diffusion, electrogenerated radicals diffusing outwards from the electrode react with the original species diffusing towards the electrode from the bulk; thus, Fc(+) reacts with dMeFc producing Fc and dMeFc(+), while MePTZ(+) reacts both with dMeFc producing MePTZ and dMeFc(+), and with Fc producing MePTZ and Fc(+). These reactions replace dMeFc with Fc at the second plateau, and both dMeFc and Fc with MePTZ at the third plateau. Since the diffusion coefficients of the three species are not equal, the mass-transfer limited currents of the second and the third oxidation wave plateaus change by approx. 10%. Numerical simulations of the experimental voltamograms support this mechanism. Similar results were also obtained for a mixture of four redoxactive compounds. The implications of this non-additive nature of currents on: (a) the use of internal voltammetric standards for quantitative analysis of a mixture of redox-active compounds; and, (b) the half wave potentials (E1/2) of the 2nd, 3rd and 4th waves for qualitative analysis, will be discussed.

Dass, Amala↗
NASA NTRS2002

Thermoelectric properties of Nb3SbxTe7-x compounds

Niobium antimony telluride, Nb3Sbx,Te7-x, was synthesized and tested for thermoelectric properties in the Thermoelectrics group at the Jet Propulsion Laboratory. The forty atoms per unit cell of Nb3Sb2Te5 and its varied mixture of atoms yield acomplicated structure, suggesting that Nb3Sb2Te5 and related compounds may exhibit low thermal conductivity and hence a higher ZT value. Nb3SbxTe7-x, compounds were synthesized and subsequently analyzed for their Seebeck voltage, heat conduction, and electrical resistivity. Results indicate that Nb3Sb2Te5 is a heavily doped semiconductor whose thermoelectric properties are compromised by compensating n-type and p-type carriers. Attempts to dope in favor of either carrier by varying the Sb:Te ratio yielded samples containing secondary metallic phases that dominated the transport properties of the resulting compounds.

thermoelectric power generation segmented↗
NASA NTRS1993

Novel Transition Metal Compounds with Promising Thermoelectric Properties

Progress in the search for new high temperature thermoelectric materials at the Jet Propulsion Laboratory is reviewed. Novel transition metal compounds were selected as potential new high performance thermoelectric materials and criteria of selection are presented and discussed. Samples of these new compounds were prepared at JPL by a variety of techniques. Encouraging experimental results obtained on several of these compounds are reported and show that they have the potential to be the next generation of thermoelectric materials.

Caillat, T.↗
NASA NTRS1990

Methods of using fluoroepoxy compounds as adhesives for fluoroplastic adherends and products made therefrom

Fluoroepoxy compounds are made by reacting a fluoroepoxy resin with an effective curing agent, such as an adduct amine, and, while the compound is sufficiently liquid to wet a fluoroplastic surface, it may be applied to a fluoroplastic adherend, such as a Teflon, to be employed as an adhesive, to form various fluoroplastic products, without requiring any surface treatment of the adherend. The compounds are intentionally formulated with high fluorine contents, normally above 46% by weight, preferably for bonding fluoroplastics with a high F-content, above 55% by weight.

Lee, Sheng Y.↗
NASA NTRS2010

Offset Compound Gear Drive

The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

Stevens, Mark A.↗
NASA NTRS2011

Performance Characterization of Loctite (Registered Trademark) 242 and 271 Liquid Locking Compounds (LLCs) as a Secondary Locking Feature for International Space Station (ISS) Fasteners

Several International Space Station (ISS) hardware components use Loctite (and other polymer based liquid locking compounds (LLCs)) as a means of meeting the secondary (redundant) locking feature requirement for fasteners. The primary locking method is the fastener preload, with the application of the Loctite compound which when cured is intended to resist preload reduction. The reliability of these compounds has been questioned due to a number of failures during ground testing. The ISS Program Manager requested the NASA Engineering and Safety Center (NESC) to characterize and quantify sensitivities of Loctite being used as a secondary locking feature. The findings and recommendations provided in this investigation apply to the anaerobic LLCs Loctite 242 and 271. No other anaerobic LLCs were evaluated for this investigation. This document contains the findings and recommendations of the NESC investigation

Dube, Michael J.↗
NASA NTRS2012

The Enantiomeric Ratios of Meteoritic Organic Compounds: Their Possible Roles in the Origin of Life

This talk will give an overview of the enantiomer (mirror-image) ratios of organic compounds in meteorites and also describe the results of the present work in my lab. The primary focus will be on sugar derivatives (sugar acids) of carbonaceous meteorites. Our work begins to address questions associated with chirality, i.e., the origins of homochirality. On Earth, biological monomers (amino acids, sugars, etc.) are usually found with one of the enantiomers more abundant than the other. However, biological polymers (proteins, nucleic acids, etc.) are only composed of one enantiomer i.e., they are homochiral. There are hints in meteorites that some organic molecules may also exist in homochiral forms. The talk will address questions such as: did extraterrestrial sources aid in the beginning of this homochirality? Do the increasing size and apparent enantiomer excesses of some meteoritic compounds also extend to larger meteoritic compounds and polymers?

Cooper, George↗
NASA NTRS2013

Micro-ion Traps for Detection of (Pre)-Biotic Organic Compounds on Comets

Comets are currently believed to be a mixture of interstellar and nebular material. Many of the volatiles in comets are attributed to interstellar chemistry, because the same species of carbonaceous compounds are also observed in ices in interstellar molecular (ISM) clouds. Comets are thus likely to be a relatively pristine reservoir of primitive material and carbonaceous compounds in our solar system. They could be a major contributor to the delivery of prebiotic organic compounds, from which life emerged through impacts on early Earth. Mass spectrometers are very powerful tools to identify unknown chemicals, and much progress bas been made in miniaturizing mas spectrometers for space applications. Most miniatu rized mass spectrometers developed to date, however, are still relatively large, power hungry, complicated to assemble, and would have significant impact on space flight vehicle total payload and resource allocations.

vanAmerom, Friso H. W.↗
NASA NTRS2014

Detection and Quantification of Nitrogen Compounds in the First Drilled Martian Solid Samples by the Sample Analysis at Mars (SAM) Instrument Suite on the Mars Science Laboratory (MSL)

The Sampl;e Analysis at Mars (sam) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected both reduced and oxidized nitrogen bearing compounds during the pyrolysis of surface materials from the three sites at Gale Crater. Preliminary detections of nitrogen species include No, HCN, ClCN, and TFMA ((trifluoro-N-methyl-acetamide), Confirmation of indigenous Martian nitrogen-bearing compounds requires quantifying N contribution from the terrestrial derivatization reagents carried for SAM's wet chemistry experiment that contribute to the SAM background. Nitrogen species detected in the SAM solid sample analyses can also be produced during laboratory pyrolysis experiments where these reagents are heated in the presence of perchlorate a compound that has also been identified by SAM in Mars solid samples.

Stern, Jennifer C.↗
NASA NTRS2014

Detection and Quantification of Nitrogen Compounds in the First Drilled Martian Solid Samples by the Sample Analysis at Mars (SAM) Instrument Suite on the Mars Science Laboratory (MSL)

The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected both reduced and oxidized nitrogen-bearing compounds during the pyrolysis of surface materials at Yellowknife Bay in Gale Crater. Preliminary detections of nitrogen species include NO, HCN, ClCN, CH3CN, and TFMA (trifluoro-N-methyl-acetamide). Confirmation of indigenous Martian N-bearing compounds requires quantifying N contribution from the terrestrial derivatization reagents (e.g. N-methyl-N-tertbutyldimethylsilyltrifluoroacetamide, MTBSTFA and dimethylformamide, DMF) carried for SAM's wet chemistry experiment that contribute to the SAM background. Nitrogen species detected in the SAM solid sample analyses can also be produced during laboratory pyrolysis experiments where these reagents are heated in the presence of perchlorate, a compound that has also been identified by SAM in Mars solid samples.

Curiosity rover↗