Ablation of carbonaceous materials in a hydrogen-helium arcjet flow
Explore the source record for details and available documents.
Park, C.↗
SEARCH · Engineering Papers
Results for “carbonaceous materials”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Laboratory experiments on carbonaceous material as a source for the red rectangle visual emissions
The authors subjected mixtures of CO, Ar, N2, H2O, and CH4 with 42 percent and 8 percent argon to an electrical discharge, froze out the reaction products at T about 20 K, and subsequently warmed the sample to room temperature. This resulted in a stable residue having broad-band fluorescence. It is suggested tht interstellar grains in the Red Rectangle/HD 44179 are coated with a residue of generally similar composition that is responsible for the broad emission feature in the 5400-7500 A spectral region.
Wdowiak, Thomas J.↗
Catalysts and methods for the conversion of carbonaceous materials to liquid fuels
The present disclosure relates to a composition that includes copper (Cu), aluminum (Al), oxygen, and an element (M) that includes at least one of magnesium, cerium, and/or a transition metal, where the copper and the element are present at a first molar ratio relative to the aluminum between about 0.1:1 and about 30:1 ((Cu+M):Al), and the copper and the element are present at a second molar ratio between about 0.1:4 and about 20:1 (Cu:M).
Vardon, Derek Richard↗
Composition and Optical Properties of Cometary Dust From Remote Sensing
Comet dust consists primarily of silicate and carbonaceous material. The carbonaceous material is.
Cometary Dust↗
Biological materials in carbonaceous chondrites
Origin of biological material in carbonaceous chondrites
CARBONACEOUS METEORITE↗
Carbonaceous chondritic material in the solar system
Carbonaceous chondritic matrix material (CCMM) appears to be an important planet-forming unit in the mid-solar system, from the orbits of Mars to that of Uranus. The type specimen for CCMM is the low-temperature (400-500 K) assemblage of clay minerals, organic polymer, magnetite, and Ni-rich iron sulfides which constitutes the black, fine-grained matrix of primitive carbonaceous chondrites. Solar-system objects which appear to be partly or wholly made of CCMM are the satellites of Mars, most asteroids, interplanetary dust, and, perhaps, comets, satellites of the outer planets and the rings of Uranus. CCMM constituents probably formed by low-temperature reactions of higher-temperature condensates with the ambient solar composition gas, or in the case of the organic polymer, by reactions of gaseous species catalyzed by solids.
Wilkening, L. L.↗
Carbon-rich aggregates in type 3 ordinary chondrites - Characterization, origins, and thermal history
Carbon-rich aggregates from three type 3.4-3.6 ordinary chondrites and two chondritic clasts have been characterized in detail, using TEM techniques. The aggregates in all the meteorites studied range in size from 5-1000 microns and consist of a fine scale intergrowth of poorly graphitized carbon, amorphous carbon, Fe,Ni metal, and minor chromite. Contrary to previous reports, well-crystallized graphite and magnetite are absent. The association of Fe,Ni metal and carbonaceous material suggests that the original carbonaceous material may have formed by Fischer-Tropsch (FT) type reactions at low temperatures (less than 400 K), possibly in the solar nebula. This carbonaceous material probably consisted of a complex mixture of hydrocarbons, kerogen-like material, and other complex organic molecules. The aggregates were subsequently accreted onto the ordinary chondrite parent bodies and underwent planetary thermal processing which resulted in the catalytic graphitization of hydrocarbons, in the presence of Fe,Ni metal, to produce poorly graphitized carbon. None of the meteorites studied experienced temperatures sufficiently high to produce crystalline, ordered graphite. Using the empirical geothermometer of Rietmeijer and Mackinnon (1985), the measured d(002) spacings of poorly graphitized carbon show that graphitization occurred at temperatures between 300 and 450 C. This range of temperatures is significantly lower than the generally quoted metamorphic temperatures for type 3.4-3.6 ordinary chondrites (about 450-500 C).
Brearley, Adrian J.↗
A carbon and nitrogen isotope study of carbonaceous vein material in ureilite meteorites
The ureilite meteorite group is known to be rich in carbon in the form of graphite/diamond veins that are associated with planetary type noble gases. This paper reports preliminary data from a systematic study of the carbon and nitrogen isotopic composition of this carbonaceous vein material. A previous study focused on the whole rock signatures and reported that the carbon inventory appeared to be dominated by the graphitic/diamond intergrowths, whereas the nitrogen was clearly composed of several distinct components including one that was isotopically light, possibly associated with the carbonaceous material. Recent studies have demonstrated that diamonds in the solar system formed in many different environments. C and N measurements from ureilitic diamond made in a similar way would be a useful addition to this overall study. The methods used for isolating diamonds of possible presolar origin from primitive meteorites are equally applicable to the processing of carbon bearing components in the ureilite group so that their stable isotopic composition can be determined. Herein we discuss conjoint C and N stepped combustion measurements made on crushed whole rock ureilite samples that have been treated with 1M HCl/9M HF to dissolve silicate and free metal. In addition, two samples have been further treated with oxidizing acids to leave a diamond rich residue.
Russell, S. S.↗
HRTEM and EFTEM Observations of Matrix in the Oxidized CV3 Chondrite ALH 84028: Implications for the Origins of Matrix Olivines
The determination of the nature, distribution, and origin of organic material in carbonaceous chondrites is fundamental to understanding early solar nebular conditions and the origin of life. Using a variety of extraction techniques, followed by detailed chemical analysis, an extensive suite of organic compounds has been identified in carbonaceous chondrites. These data have provided key information on the diversity and isotopic composition of the organic component in chondrites. However, one disadvantage of extraction techniques is that all information regarding the spatial distribution of the organics on a fine scale is lost. This is especially important for the insoluble macromolecular carbon, which constitutes approximately 70% of the carbon in carbonaceous chondrites such as Murchison. The distribution and mineralogical associations may provide important constraints on the possible origins of the carbonaceous material. Our previous studies of the CV3 chondrites Allende and Vigarano have demonstrated that energy filtered transmission electron microscopy (EFTEM), combined with high resolution TEM (HRTEM) are powerful tools for the in situ characterization of insoluble organic matter in carbonaceous chondrites. In this study, we have used SEM and TEM techniques to characterize the matrix mineralogy of the CV3 chondrite ALH 84028 and examine the distribution and mineralogical associations of carbon. We are especially interested in establishing whether the occurrence of poorly graphitized carbon (PGC), observed in Allende matrix olivines, is common to all oxidized CV3 chondrites or is a unique feature of Allende.
Abreu, Neyda M.↗
Raman observations on individual interplanetary dust particles
A Raman study of 20 representative interplanetary dust particles (IDPs) belonging to different infrared spectral classes is discussed. Six different groups of Raman spectra were discerned among the IDPs studied. Groups 1-5 exhibit the Raman signature of poorly crystallized carbonaceous material, with the degree of disorder of this material increasing from group 1 (most ordered) to group 5 (least ordered). Group 1 contains IDPs that have infrared spectra characteristic of olivines, and are deuterium depleted, while those in groups 2, 3, and 4 contain less ordered carbonaceous material and are deuterium enriched, suggesting different carbonaceous carrier phases for deuterium depletions and enrichments. Groups 5 and 6 contain little or no carbonaceous material, with an abundance of deuterium. No obvious relationship was found between Raman groups and infrared classes based on the 10 micron absorption band due to silicates. Because silicates are known to be present, but are not seen, it is presumed that silicate grains are coated with and/or imbedded in carbonaceous material. Several IDPs show broad visible laser-induced photoluminescence, probably produced by a carbonaceous component.
Wopenka, Brigitte↗
On the Importance of Producing and Characterizing Laboratory Analogs of Cosmic Grains, Planetary Atmospheric Aerosols, and Surface Materials
Carbonaceous dust and aerosols have been observed in interstellar/circumstellar and planetary environments. Dedicated laboratory experiments have been developed to produce analogs of these solid materials under different experimental conditions (molecular precursors, temperature, pressure, energy source…). These experimental studies are key to investigating the physical and chemical processes that drive the formation of solid particles from gas and solid phase molecular precursors in astrophysical and planetary environments. They also allow the characterization of the physical, optical, and chemical properties of these laboratory-generated analogs, hence providing critical information that can be used as input parameters in models for the analysis and interpretation of observational data. Here, as an example of these laboratory efforts, we will present various studies that combined (1) experiments performed with the NASA Ames COSmIC facility to produce analogs of Titan’s atmospheric aerosols and cosmic grains from gas phase molecular precursors, and (2) the characterization of these analogs with the NASA Ames Optical Constants Facility (OCF) to provide the real and imaginary parts of their refractive indices, n + ik, to the community, from the visible to the far-infrared (0.59–200 µm, 16,950–50 per cm). We will also discuss the importance of the wavelength and spectral range coverage of these optical constants, n and k, for their use in radiative transfer, atmospheric and reflectance models, and present a new effort to develop an Optical Constant database (OCdb) to provide this critical data to the scientific community.
Cosmic Grains↗
Isotopic characteristics of simulated meteoritic organic matter. I - Kerogen-like material
Carbonaceous residues from a variety of laboratory syntheses yield release patterns for C and H isotopes during stepwise combustion that fail to mimic the striking patterns characteristic of meteoritic kerogen-like residues that otherwise superficially resemble them. It seems likely that the meteoritic material comprises a complex mixture of substances having different origins and/or synthesis conditions.
Kerridge, John F.↗
The possible presence of interstellar PAHs in meteorites and interplanetary dust particles
The Raman spectra of interplanetary dust particles (IDPs) collected in the stratosphere show two bands at about 1350 and 1600 delta cm(-1) and a broader feature between 2200 and 3300 delta cm(-1) that are characteristic of aromatic molecular units with ordered domains smaller than 25A in diameter. This suggests that the carbonaceous material in IDPs may be similar to the polymeric component seen in meteorites, where this material is thought to consist of aromatic molecular units that are randomly inter-linked by short aliphatic bridges. The features in the Raman spectra of IDPs are similar in position and relative strength to interstellar infrared emission features that have been attributed to vibrational transitions in free molecular polycyclic aromatic hydrocarbons (PAHs). The Raman spectra of some IDPs also showed photoluminescence that is similar to the excess red emission from some astronomical objects and that has also been attributed to PAHs and PAH-related materials. Moreover, a part of the carbonaceous phase in IDPs contains deuterium to hydrogen ratios that are far greater than those found in terrestrial samples. Deuterium enrichment is expected in small free PAHs that are exposed to ultraviolet radiation in the interstellar medium. Taken together, these observations suggest that some fraction of the carbonaceous material in IDPs may have been produced in circumstellar dust shells and only slightly modified in interstellar space. Since many, if not most, IDPs come from comets, this supports the view that cometary material contains primitive components which can provide clues about early solar system (and perhaps even interstellar and circumstellar) processes.
Allamandola, L. J.↗
Organic Matter in Itokawa Particles
The first Hayabusa mission returned samples from the near-Earth S-type asteroid 25143 Itokawa to Earth in 2010[1]. Although Itokawa has a lithology related to ordinary chondrites(OCs) that typically have low organic contents, several Itokawa particles were found to contain organic matter (OM)[2-5]. However, there was not an explicit conclusion to the origin of the observed OMin these early studies. We have extended our search for OM into other Itokawa grains. Here, we report extraterrestrial OM (macromolecular carbon and amino acids) observed in six Itokawa particles(including a category1 particle: RA-QD02-0162[#62; also nicknamed “Amazon”],and five category3 carbon-rich particles:RA-QD02-0012[#12], RA-QD02-0078[#78], RB-CV-0029[#29], RB-CV-0080 [#80] and RB-QD04-0052[#52]).All allocated Itokawa samples were initially analysed by spot and point-by-point mapping Raman spectroscopic analysis at the Open University, UK. Amazon was then transferred and mounted into indium on an aluminium stub, which was studied with a NanoSIMS 50L ion microprobe for its H,C,N isotopic compositions. The rest of the samples were mounted in sterile gold foils, and the amino acid contents of their acid hydrolysed hot water extracts were obtained with a liquid chromatography with tandem fluorescence and accurate mass detection at NASA Goddard Space Flight Center, USA. Based on the observation of the Raman parameters(e.g. the peak locations and widths of the defect (D) and graphite (G) bands)[6], a significant variety of carbonaceous materials has been observed in Amazon. The carbonaceous materials include primitive and unaltered OM that shares similarity with the IOM in primitive (CI,CM,CR) carbonaceous chondrites, as well as OM that has been heavily graphitised. The organic structure of the heated material is best represented by nanocrystalline graphite, comparable to that observed for metamorphosed meteorites (e.g., L3–6 Inman, Tieschitz and New Concord,CV3 Allende, and EH4 Indarch),suggesting peak metamorphic temperatures (PMT) of >~600°C. The thermal history recorded in the graphitic OM agrees with PMT estimates for returned Itokawa regolith grains (600–800°C)[7].We have obtained the H,C,N isotopic compositions for the primitive OM in Amazon, which exhibits unambiguously extraterrestrial isotopic signatures (δD = +4868±2288‰; δ13C = −24±5‰; δ15N = +344±20‰), contrasting to the typically negative isotopic values obtained for terrestrial organic matter[8]. The δD and δ13C values of the organic material in Amazon are comparable to OCs, however, the δ15N value is higher than that typically observed for OCs (δ15N = −47 to +36‰), and is similar to that of CRs (δ15N = +153 to +309‰)[9].Our data suggest a genetic link between the primitive organic material observed in Itokawa to CRs and IDPs for they share similar D, 13C and 15N enrichments[10].The high carbon contents of the five category 3 Itokawa particles suggest potentially higher OM abundances, hence we extracted and analysed amino acids in these samples. Although terrestrial contamination was observed primarily as L-protein amino acids, several terrestrially uncommon non-protein amino acids were also observed at low abundances, such as β-aminoisobutyric acid (β-AIB),β-amino-n-butyric acid (β-ABA), and β-alanine. Itokawa amino acid content observed here was dissimilar to thermally altered OCs, but preliminarily analogous to more aqueously altered CR2s.Continued evolution of Itokawa is evident by the in fall of primitive organic material derived from CRs/IDPs, accounting for a complex interplay between the remnant Itokawa silicates with exogenous organics. The results reported here are the first evidence of extraterrestrial OM in asteroid material from a sample-return mission, showcasing a working protocol for analysing samples returned by the Hayabusa2 and OSIRIS-REx missions
Q. H. S. Chan↗
Organic preservation of vase‐shaped microfossils from the late Tonian Chuar Group, Grand Canyon, Arizona, USA
Abstract Vase‐shaped microfossils (VSMs) are found globally in middle Neoproterozoic (800–730 Ma) marine strata and represent the earliest evidence for testate (shell‐forming) amoebozoans. VSM tests are hypothesized to have been originally organic in life but are most commonly preserved as secondary mineralized casts and molds. A few reports, however, suggest possible organic preservation. Here, we test the hypothesis that VSMs from shales of the lower Walcott Member of the Chuar Group, Grand Canyon, Arizona, contain original organic material, as reported by B. Bloeser in her pioneering studies of Chuar VSMs. We identified VSMs from two thin section samples of Walcott Member black shales in transmitted light microscopy and used scanning electron microscopy to image VSMs. Carbonaceous material is found within the internal cavity of all VSM tests from both samples and is interpreted as bitumen mobilized from Walcott shales likely during the Cretaceous. Energy dispersive X‐ray spectroscopy (EDS) and wavelength dispersive X‐ray spectroscopy (WDS) reveal that VSM test walls contain mostly carbon, iron, and sulfur, while silica is present only in the surrounding matrix. Raman spectroscopy was used to compare the thermal maturity of carbonaceous material within the samples and indicated the presence of pyrite and jarosite within fossil material. X‐ray absorption spectroscopy revealed the presence of reduced organic sulfur species within the carbonaceous test walls, the carbonaceous material found within test cavities, and in the sedimentary matrix, suggesting that organic matter sulfurization occurred within the Walcott shales. Our suite of spectroscopic analyses reveals that Walcott VSM test walls are organic and sometimes secondarily pyritized (with the pyrite variably oxidized to jarosite). Both preservation modes can occur at a millimeter spatial scale within sample material, and at times even within a single specimen. We propose that sulfurization within the Walcott Shales promoted organic preservation, and furthermore, the ratio of iron to labile VSM organic material controlled the extent of pyrite replacement. Based on our evidence, we conclude that the VSMs are preserved with original organic test material, and speculate that organic VSMs may often go unrecognized, given their light‐colored, translucent appearance in transmitted light.
58 GEOSCIENCES↗
Characterization of Organic Materials in the Xenolithic Clasts in Sharps (H3.4) Meteorite Using Micro-Raman Spectroscopy
Graphitization of carbon is an irreversible process which alters the structure of graphitic materials in response to the increase in metamorphic grade (temperature and/or pressure). Carbonaceous materials offer a reliable geothermometer as their Raman spectra change systematically with increasing metamorphic grade. In this study, we identified carbonaceous materials in the xenolithic clasts in Sharps and interpreted their metamorphic history by revealing the structural organization (order) of the polyaromatic organic phases using micro-Raman spectroscopy.
Chan, Q. H. S.↗
Characterization of Organic Materials in the Xenolithic Clasts in Sharps (H3.4) Meteorite Using Microraman Spectroscopy
Graphitization of carbon is an irreversible process which alters the structure of graphitic materials in response to the increase in metamorphic grade (temperature and/or pressure). Carbonaceous materials offer a reliable geothermometer as their Raman spectra change systematically with increasing metamorphic grade [1-3]. In this study, we identified carbonaceous materials in the xenolithic clasts in Sharps and interpreted their metamorphic history by revealing the structural organization (order) of the polyaromatic organic phases using μ-Raman spectroscopy.
Chan, Q. H. S.↗
Optical properties of carbonaceous chondrites and their relationship to asteroids
Results of diffuse reflectance measurements of nine samples of carbonaceous chondrites (one C1, three C2, four C3, and one C4) and one iron meteorite, Odessa. Measurements were also made of mineral mixtures in an attempt to understand the cause of some features of the meteorite reflectances. The C1 and C2 carbonaceous chondrites have reflectances low enough to match the anomalously low albedos of some asteroids. Some asteroids have spectral reflectances similar to carbonaceous chondrites, whereas others with flat or F-type curves appear to match simulated mineral mixtures with slightly greater amounts of the carbonaceous component than those found in the meteorites. This observation suggests either that surface physical processes such as melting may be enhancing the optical effect of opaque carbonaceous material on some asteroid surfaces and/or that these asteroids contain even more carbonaceous material than the C1 meteorites.
Johnson, T. V.↗