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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Mass Spectra Deconvolution of Gaseous Mixtures Containing Volatile Organic Compounds

The Spacecraft Atmosphere Monitor (S.A.M.) analyzes all gaseous pollutants in the 1-150Th mass-to-charge range based on their positive-ion mass spectra. Of particular interest is the Trace Gas Analysis (TGA) mode of operation in which S.A.M detects minute amounts of volatile organic compounds (VOC). Pollutant component of the ambient air is sampled on demand in twenty full mass spectra per second. All spectra is accumulated in two-second intervals by an on-board Field Programmable Gate Arrays (FPGA) unit. Mass spectra represents the number of detected fragment ions in a given mass-to-charge ratio channel. Electron impact ionization of neutral molecules results in creation of numerous fragment ions and most of organic compounds will contribute several identical fragments. Despite the presence of these molecular isobars, we developed the deconvolution algorithm capable of identifying target species based on their characteristic fragmentation patterns. We investigate the efficiency of deconvolution algorithm as a function of mass resolution with which mass spectrum is acquired. Higher the mass resolution, better the chances are to distinguish between stereoisomers using their fragmentation propensities, but also results in higher data volumes to be processed by a set of small footprint software stacks hosted by an on-board computer. Finding the balance between deconvolution accuracy and generated data volume under time constrains and limited computing resources is the main topic of this study.

Darrach, M.↗
NASA NTRS2021

Volatile Organic Compounds Emitted from Air Fresheners: Plug-Ins at Home and Little Trees in Cars

Air fresheners contain volatile organic compounds (VOCs), some of which are possible hazardous air pollutants, carcinogens, or chemicals associated with adverse health effects such as asthma. This screening study identifies VOCs emitted from two types of air fresheners. Plug-in air fresheners are household products that release scents from a heated liquid. Little Tree air fresheners are commonly used solid devices designed to hang in from the rear view mirror in cars. VOCs that were released from heated samples of air fresheners were identified by gas chromatography mass spectroscopy (GCMS). Amongst VOCs commonly known to have scent properties, this screening also revealed the presence of compounds that are not associated with fragrances and that may have adverse health effects. In a pilot study to characterize how air fresheners affect air quality in real settings, air samples were collected on solid-phase microextraction (SPME) field samplers in a home setting and inside a vehicle, before and during air-freshener use. This pilot demonstrated some limited potential for SPME field samplers to track changes in VOC levels in real-life settings.

Adriana Pino-Delgado↗
NASA NTRSDate not supplied

Rotational Spectroscopy is SubLIME: Site-Specific Identification of Compounds Formed on UV-photolyzed Cosmcs Ice

A variety of organic compounds has been detected in comets, meteorites, and the cold gas enveloping infant stars. These compounds display a range of complexity and include so-called complex organic molecules that may have astrobiological implications. Laboratory studies of photolyzed and nonirradiated interstellar, planetary, and cometary ices have demonstrated many astrochemical formation routes and require sensitive analytical techniques to identify the composition of ice and gas products formed. The unique identification of organics can be challenging and often requires structure-specific techniques to identify structural isomers, conformers, and isotopologues. We present the approaches used in SubLIME, the Sublimation of Laboratory Ices Millimeter/submillimeter Experiment, which uses the structure-specificity of rotational spectroscopy to identify the composition and abundances of sublimated products of UV-photolyzed ice samples. Ices are formed and photolyzed at low temperature (~10 K) and slowly heated to 300 K to sublimate the volatile products. The gas mixture is then investigated with millimeter/submillimeter spectroscopy, and the resulting spectra compared to observational spectra collected with submillimeter/far-IR telescopes. We present the experimental set-up and results of UV-photolyzed interstellar ice analogues containing water (H O) and carbon monoxide (CO). Formation routes for identified molecules are proposed for follow-up experimental and theoretical investigations.

Olivia H. Wilkins↗
NASA NTRSDate not supplied

Plasma Abatement of Volatile Organic Compounds for Treatment of Spacecraft Trash Combustion Gaseous Effluents.

One approach that has been investigated for trash management aboard long-duration crewed exploration space missions is the so-called Trash-to-Gas approach. This technology uses a thermal process (i.e., combustion, pyrolysis, etc.) to convert crew trash into relatively non-reactive gases (i.e., CO2, CO, etc.) that can be easily vented overboard. One difficulty with this approach is the potential for the contamination of the spacecraft habitable volume from the myriad volatile organic compounds (VOCs) that are concurrently produced from these thermal processes. One possible VOC abatement process is to apply a plasma to the effluent gases. Plasmas provide high energy electrons and ions that are capable of breaking down gaseous organic species generally into smaller compounds. To explore Plasma VOC abatement, the authors constructed a plasma gas system that recirculates a particular VOCladen gas mixture through a plasma torch. This allows the periodic collection of aliquots of gaseous samples for subsequent analyses via gas chromatography mass spectrometry, designed to quantify the remaining VOC materials. The VOCs evaluated included 100 ppm of acetone, benzene, ethanol, and pentane in a background of carbon dioxide. The plasma conversion of all analytes followed first order rate kinetics, and complete VOC elimination was observed after 10 min or less of treatment, for all analytes measured. Additionally, it was observed that the plasma caused the conversion of CO2 into oxygen and CO.

Joel A. Olson↗
NASA NTRSDate not supplied

Plasma Abatement of Volatile Organic Compounds

One difficulty with crewed space operations is the potential for the contamination of the spacecraft habitable volume from volatile organic compounds (VOCs) that may be present. One possible VOC abatement process is to apply a plasma to the contaminated gases. Plasmas provide high energy electrons and ions that are capable of breaking down gaseous organic species generally into smaller compounds. To explore plasma VOC abatement, the authors constructed a plasma gas system that recirculates a particular VOC-laden gas mixture through a plasma torch. This allows for the periodic collection of aliquots of gaseous samples for subsequent analyses via gas chromatography mass spectrometry, designed to quantify the remaining VOC materials. The VOCs evaluated included 100 ppm of acetone, benzene, ethanol, and pentane in a background of carbon dioxide. The plasma conversion of all analytes followed first-order rate kinetics, and VOC elimination was observed after 10 min or less of treatment for all analytes measured. Additionally, it was observed that the plasma caused the conversion of CO 2 into oxygen and CO.

Joel A. Olson↗
NASA NTRS2023

Plasma Treatment of Volatile Organic Compounds (VOCs)

Plasma is an energetic source that has thermal and non-thermal chemistry applications. For this work, we pursued the investigation of plasma as a non-consumable based method of treating spacecraft volatile organic compounds (VOCs) in order to mitigate or eliminate potential hazards. This work focused on select compounds but also applied the technology to program-funded trash-to-gas (TtG) effluent gas.

Logistics Management↗
DOE OSTI2020

Organic semiconductor compounds and methods of use

Organic perylene diimide-based compounds are provided. Methods of producing the organic compounds is also provided as well as methods of their use including, among other things, their use as organic semiconductor materials.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Surface-modified cyanide-based transition metal compounds

A system, method, and articles of manufacture for a surface-modified transition metal cyanide coordination compound (TMCCC) composition, an improved electrode including the composition, and a manufacturing method for the composition which may include multiple chelation species (Che_x). The composition, compound, device, and uses thereof according to AxMn(y-k)Mjk[Mnm(CN)(6-p-q)(NC)p(Che_I)rq]z.CHE_GROUP (Vac)(1-z).nH2O, wherein CHE_GROUP includes one or more chelation materials selected from the group consisting of (Che_I)rw, (Che_II)sv, and combinations thereof, and wherein 0 < j≤4, 0≤k≤0.1, 0≤(p+q)≤6, 0 < x≤4, 0 < y≤1, 0 < z≤1, 0 < w≤0.2; −3≤r≤3; 0 < v≤0.2; −3≤s≤3; and 0≤n≤6; wherein x+2(y−k)+jk+(m+(r+1)q−6)z+wr+vs=0.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Surface-modified cyanide-based transition metal compounds

A system, method, and articles of manufacture for a surface-modified transition metal cyanide coordination compound (TMCCC) composition, an improved electrode including the composition, and a manufacturing method for the composition which may include multiple chelation species (Che_x). The composition, compound, device, and uses thereof according to AxMn(y-k)Mjk[Mnm(CN)(6-p-q)(NC)p(Che_I)rq]z. CHE_GROUP (Vac)(1-z).nH2O, wherein CHE_GROUP includes one or more chelation materials selected from the group consisting of (Che_I)rw, (Che_II)sv, and combinations thereof, and wherein 0 < j≤4, 0≤k≤0.1, 0≤(p+q)≤6, 0 < x≤4, 0 < y≤1, 0 < z≤1, 0 < w≤0.2; −3≤r≤3; 0 < v≤0.2; −3≤s≤3; and 0≤n≤6; wherein x+2(y−k)+jk+(m+(r+1)q−6)z+wr+vs=0.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Methods for making bacteriochlorin macrocycles comprising an annulated isocyclic ring and related compounds

Described herein are bacteriochlorins comprising an annulated isocyclic ring such as a compound Formula I: or a metal conjugate thereof, wherein: R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, and Z are each as defined herein. Also described are methods and intermediates for the synthesis of bacteriochlorins comprising an annulated isocyclic ring, and methods of using such bacteriochlorins for, among other things, diagnostic and therapeutic purposes such as, e.g., luminescent compounds in flow cytometry, and/or as active agents in photodynamic therapy (PDT).

Lindsey, Jonathan S.↗
DOE OSTI2021

Microorganisms and methods for producing 2-pyrone-4,6-dicarboxylic acid and other compounds

Recombinant microorganisms configured for enhanced production of compounds such as 2-pyrone-4,6-dicarboxylic acid (PDC) and methods of using the recombinant microorganisms for the production of these compounds. The recombinant microorganisms include one or more modifications that reduce 2-pyrone-4,6-dicarboxylic acid (PDC) hydrolase activity, 4-carboxy-2-hydroxy-6-methoxy-6-oxohexa-2,4-dienoate (CHMOD) cis-trans isomerase activity, 4-carboxy-2-hydroxy-6-methoxy-6-oxohexa-2,4-dienoate (CHMOD) methyl esterase activity, and/or vanillate/3-O-methylgallate O-demethylase activity. The recombinant microorganisms can be used to generate PDC from media comprising plant-derived phenolics, such as syringyl phenolics, guaiacyl phenolics, and p-hydroxyphenyl phenolics. The plant-derived phenolics can be derived from pretreated lignin, including depolymerized lignin or other chemically altered lignin.

Noguera, Daniel R.↗
DOE OSTI2024

Separation of compounds

A method for separating liquids is disclosed. A feed stream is passed into a separator. The feed stream comprising an organic compound, carbon dioxide, and oxides selected from the group consisting of sulfur oxides, nitrogen oxides, ozone and combinations thereof. A portion an organic-rich stream is separated from a portion of an inorganic-rich stream through separation by gravity. The organic-rich stream contains a portion of the organic compound and a first portion of the carbon dioxide. The inorganic-rich stream contains a portion of the oxides and a second portion of the carbon dioxide.

Baxter, Larry↗
DOE OSTI2024

Compounds and composition for preparation of lithium-loaded plastic scintillators

A scintillator material includes a polymer matrix, a primary dye in the polymer matrix, the primary dye being a fluorescent dye; a secondary dye, and a Li-containing compound in the polymer matrix, where the Li-containing compound is a Li salt of a short-chain aliphatic acid. In addition, the scintillator material exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons.

Zaitseva, Natalia P.↗
DOE OSTI2025

Spherical Congeners of Polyaromatic Compounds Approaching C 20 - and C 60 -Fullerene-Type Structures

A series of three symmetric, hollow spherical, and shape-persistent molecular organic cages analogous to C 20 and C 60 were examined by computational modeling, analyzing structural elements, strain indicators, and physical properties relevant for potential applications. The compounds are covalent aromatic cages based on 1,3,5-substituted benzene nodes linked by paraphenylene or para-pyrenylene-connectors, with diameters varying from 2.3 to 4.2 nm. The apertures in the cage interior are varied by virtue of the cage type (C 20 - or C 60 -type cage) and the linear connectors placed between the C 6 H 3 -units. NBO and MESP analyses indicate the presence of electrophilic and nucleophilic sites in the molecular skeleton. In the cages with the phenylene-connectors, the HOMO−LUMO gaps are close to 4.0 eV. In the cage coated with an enlarged polyaromatic spacer (pyrene-unit), the gap is reduced by approximately 0.4 eV.

Aromatic compounds↗