Carbon-bearing Materials Research Articles

Energy efficiency of carbon-bearing materials in arc steelmaking furnaces and methods of improving it

This article examines results from the use of carbon-bearing materials in different generations of arc steelmaking furnaces. It is shown that the changes which have occurred in the design of electric furnaces and electric steelmaking technology have been accompanied by decreases in the degree of secondary combustion of CO to CO2, the value of the coefficient which characterizes the assimilation of heat from this reaction, and the efficiency of the use of carbon as an energy carrier.

Effect of secondary electrospark treatment with carbon-bearing materials on the properties of titanium alloys

The Scientific Training Center for Self-Sustaining High-Temperature Synthesis at the Moscow Institute of Steel and Alloys has conducted a study of the structure and properties of two-layer electrospark coatings on titanium alloy OT4-1. The coatings were applied by the successive use of STS electrode material STIM-2 (TiC - 20% Ni) (primary treatment) and several different carbon-bearing materials (secondary treatment). It was established that treatment of the surface with carbon-bearing materials decreases the friction coefficient and increases the resistance of specimens of the titanium alloy to heat and wear.

Analysis of Carbon-Bearing Materials for Use as First Wall Armor in the High Average Power Laser (HAPL) Chamber

The characterization of lifetime-component capabilities of various chamber armors is a critical path to the development of the High Average Power Laser (HAPL) reactor design. Previous studies have examined tungsten as an armor material to protect the low-activation ferritic steel first wall from x-ray and ion damage.Carbon-bearing materials are of interest as candidate armor materials due to their desirable thermal and mechanical properties. This analysis examines and compares several carbon-bearing materials: silicon carbide, graphite, engineered graphitic materials and carbon nanotube composites.The transient thermal response of these materials was simulated with the BUCKY 1-D radiation hydrodynamics code utilizing the standardized HAPL x-ray and ion threat spectra. Evacuated and buffer gas filled bare-walled configurations were simulated.

Low-nitrogen coal as a carburizer in the production of special steels

Residual elements in the batch have a considerable influence of the quality of converter steel. Of these, nitrogen is the most difficult to regulate in smelting and represents one of the main obstacles to the production of high-quality steel—in particular, steel for wire rod, springs, and cord [1–3]. High nitrogen content in steel produces strain aging and is associated with lower plasticity of cold-rolled and tempered low-carbon steel sheet. Carbon-bearing materials—carburizers—are used for ladle treatment of such special steels. Such materials must have a low content of nitrogen and sulfur (≤ 0.5%). In addition, their moisture content and yield of volatiles must be as low as possible. They are confined to size class 6-1 mm.

Dependence of the service properties of carbon-bearing materials on the processes of spinel formation that occur in the structure of refractory in service

Dependence of the service properties of carbon-bearing materials on the processes of spinel formation that occur in the structure of refractory in service

Atomic Weights of the Elements 2005

The latest evaluation of atomic weight determinations and other cognate data has warranted 16 changes for the standard atomic weights of the elements, Ar(E), from those published previously in the Table of Atomic Weights 2001. The revised standard atomic weight are as follows: Ar(Al)=26.9815386(8), Ar(Bi)=208.98040(1), Ar(Cs)=132.9054519(2), Ar(Co)=58.933195(5), Ar(Au)=196.966569(4), Ar(La)=138.90547(7), Ar(Mn)=54.938045(5), Ar(Nd)=144.242(3), Ar(P)=30.973762(2), Ar(Pt)=195.084(9), Ar(Sm)=150.36(2), Ar(Sc)=44.955912(6), Ar(Na)=22.98976928(2), Ar(Ta)=180.94788(2), Ar(Tb)=158.92535(2), Ar(Th)=232.03806(2). A recommendation is made that δ13C values of all carbon-bearing materials be measured and expressed relative to Vienna-Pee Dee Belemnite on a scale normalized by assigning consensus values of −46.6‰ to L-SVEC lithium carbonate and +1.95‰ to NBS 19 calcium carbonate.

Radiocarbon dating of primary aragonite by sequential extraction of CO2

This paper describes the potential of correcting the 14C age shift resulting from the contamination of primary aragonites by detrital carbonates using online sequential extraction of CO2. The experiments were carried out on laminated lacustrine aragonites collected from Holocene Dead Sea sediment sections. X-ray diffraction analysis revealed the presence of detrital calcite interpreted to originate from the watershed and transported to the lake with runoff. The contamination could not be separated physically from the sample, potentially contributing decayed 14C (‘dead carbon’) and increasing the age of the aragonite. Sequential extraction of successive fractions of CO2 unveiled the effect of detrital material on the 14C ages, and showed that the first CO2 extract represents the least contaminated 14C fraction that provides the best approximation for the true 14C age (which includes the lake’s reservoir age). We calculated the age offset contributed by the contamination range encountered in this study (1-21%) to be about 900 years per 10% contamination. The sequential extraction procedure is recommended for 14C dating of Holocene age lacustrine carbonates suspected to be contaminated with extraneous carbon-bearing materials.

On the discovery of CO nighttime emissions on Titan by Cassini/VIMS: Derived stratospheric abundances and geological implications

We present a quantitative analysis of CO thermal emissions discovered on the nightside of Titan by Baines et al. [2005. The atmospheres of Saturn and Titan in the near-infrared: First results of Cassini/VIMS. Earth, Moon, and Planets, 96, 119–147]. in Cassini/VIMS spectral imagery. We identify these emission features as the P and R branches of the 1-0 vibrational band of carbon monoxide (CO) near 4.65 μm. For CH 3D, the prominent Q branch of the ν 2 fundamental band of CH 3D near 4.55 μm is apparent. CO 2 emissions from the strong v 3 vibrational band are virtually absent, indicating a CO 2 abundance several orders of magnitude less than CO, in agreement with previous investigations. Analysis of CO emission spectra obtained over a variety of altitudes on Titan's nightside limb indicates that the stratospheric abundance of CO is 32±15 ppm, and together with other recent determinations, suggests a vertical distribution of CO nearly constant at this value from the surface throughout the troposphere to at least the stratopause near 300 km altitude. The corresponding total atmospheric content of CO in Titan is ∼2.9±1.5×10 14 kg. Given the long lifetime of CO in the oxygen-poor Titan atmosphere (∼0.5–1.0 Gyr), we find a mean CO atmospheric production rate of 6±3×10 5 kg yr −1. Given the lack of primordial heavy noble gases observed by Huygens [Niemann et al., 2005. The abundances of constituents of Titan's atmosphere from the GCMS on the Huygens probe. Nature, 438, 779–784], the primary source of atmospheric CO is likely surface emissions. The implied CO/CH 4 mixing ratio of near-surface material is 1.8±0.9×10 −4, based on an average methane surface emission rate over the past 0.5 Gyr of 1.3×10 −13 gm cm −2 s −1 as required to balance hydrocarbon haze production via methane photolysis [Wilson and Atreya, 2004. Current state of modeling the photochemistry of Titan's mutually dependent atmosphere and ionosphere. J. Geophys. Res. 109, E06002 Doi:10.1029/2003JE002181]. This low CO/CH 4 ratio is much lower than expected for the sub-nebular formation region of Titan and supports the hypothesis [e.g., Atreya et al., 2005. Methane on Titan: photochemical-meteorological-hydrogeochemical cycle. Bull. Am. Astron. Soc. 37, 735] that the conversion of primordial CO and other carbon-bearing materials into CH 4-enriched clathrate-hydrates occurs within the deep interior of Titan via the release of hydrogen through the serpentinization process followed by Fischer–Tropsch catalysis. The time-averaged predicted emission rate of methane-rich surface materials is ∼0.02 km 3 yr −1, a value significantly lower than the rate of silicate lava production for the Earth and Venus, but nonetheless indicative of significant active geological processes reshaping the surface of Titan.

Atomic weights of the elements 2005 (IUPAC Technical Report)

The latest evaluation of atomic weight determinations and other cognate data has warranted 16 changes for the standard atomic weights of the elements, Ar(E), from those published previously in the 2001 Table of Atomic Weights. The revised standard atomic weights are as follows: Ar(Al) = 26.981 5386(8), Ar(Bi) = 208.980 40(1), Ar(Cs) = 132.905 4519(2), Ar(Co) = 58.933 195(5), Ar(Au) = 196.966 569(4), Ar(La) = 138.905 47(7), Ar(Mn) = 54.938 045(5), Ar(Nd) = 144.242(3), Ar(P) = 30.973 762(2), Ar(Pt) = 195.084(9), Ar(Sm) = 150.36(2), Ar(Sc) = 44.955 912(6), Ar(Na) = 22.989 769 28(2), Ar(Ta) = 180.947 88(2), Ar(Tb) = 158.925 35(2), Ar(Th) = 232.038 06(2). A recommendation is made that δ13C values of all carbon-bearing materials be measured and expressed relative to Vienna Pee Dee Belemnite (VPDB) on a scale normalized by assigning consensus values of -46.6 ‰ to L-SVEC lithium carbonate and +1.95 ‰ to NBS 19 calcium carbonate.

Some perspectives on isotope biosignatures for early life

The idea of using stable isotope compositions of light elements, particularly of carbon, as a sign of biological activities (biosignatures), both present and past, dates back to the dawn of stable isotope geochemistry in the 1940s. In the wake of the discovery of large variations in 13C/ 12C ratios among various carbon-bearing materials including plants and fossil fuels, the contentious debate ensued between Kalervo Rankama and Harmon Craig in the early 1950s whether the origin of graphitic carbon in ancient rocks (biogenic vs. abiogenic) can be uniquely identified by its isotopic compositions. During the last half-century, great progress has been made in understanding biogeochemical processes in modern and ancient terrestrial environments. Rapid developments in the last decade of novel analytical techniques and the birth of new geoscience fields such as geomicrobiology and astrobiology has prompted resurgence in the application not only of conventional light stable isotopes, but also of those of metal and other intermediate elements. However, recent debates on the origin of graphitic carbons from Early Archean rocks from Australia and Greenland are very much reminiscent of the Rankama–Craig debate half a century ago. Here, an attempt is made to review briefly the history of isotope biosignatures and to critically assess current criteria for early life. A number of possible abiotic pathways exist that lead to the synthesis of various organic and reduced carbon compounds (alkanes, PAH, amino acids, lipids, graphitic carbon, etc.) depleted in 13C due to large kinetic isotope effects (up to ca. − 60‰). It also seems very likely that the mantle contains indigenous carbons (graphite, diamond, dissolved carbons, carbide) with low δ 13C values (− 20‰ to − 30‰), which have previously been considered recycled sedimentary organic carbons or surface contamination. This analysis prompts us to reassess our current and future strategies for identifying early and extraterrestrial life using isotope biosignatures.

Quantitative modeling of the spectral reflectance of Kuiper Belt objects and Centaurs

Reflectance spectroscopy of Solar System bodies provides a rich source of information on their compositions (minerals, ices, metals, and macromolecular carbon-bearing materials). Models calculated with radiative transfer theories for the spectral distribution of diffusely scattered sunlight from planetary surfaces yield information on the compositions, abundances, physical states, layering, and particle microstructure of those surfaces. We discuss and evaluate the scattering theories of Hapke and Shkuratov that are widely used for modeling the reflectance spectra and color data for Kuiper Belt objects, Centaur objects, and other airless bodies in the Solar System. Both theories yield good models of the reflectance spectrum of Centaur 5145 Pholus using five components (ices, carbon, a silicate mineral, and a complex organic material), although the derived abundances differ widely. To cite this article: D.P. Cruikshank et al., C. R. Physique 4 (2003).

Reply [to “Comment on “An optical search for small comets” by R. L. Mutel and J. D. Fix”

Journal of Geophysical Research: Space PhysicsVolume 106, Issue A11 p. 24863-24868 CommentariesFree Access Reply [to “Comment on “An optical search for small comets” by R. L. Mutel and J. D. Fix”] R. L. Mutel, R. L. MutelSearch for more papers by this authorK. G. Gayley, K. G. GayleySearch for more papers by this authorJ. D. Fix, J. D. FixSearch for more papers by this author R. L. Mutel, R. L. MutelSearch for more papers by this authorK. G. Gayley, K. G. GayleySearch for more papers by this authorJ. D. Fix, J. D. FixSearch for more papers by this author First published: 01 November 2001 https://doi.org/10.1029/2001JA000029Citations: 2AboutReferencesRelatedInformationPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessClose modalShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References Cloutis, E., M. Gaffey, T. Moslow, Spectral reflectance properties of carbon-bearing materials, Icarus, 107, 276– 287, 1994. Evans, R. W., et al., Asteroid trails in Hubble space telescope, Icarus, 131, 261– 282, 1998. Fernandez, J. A., T. Gallardo, The transfer of comets from parabolic orbits to short-period orbits: Numerical studies, Astron. Astrophys., 281, 911– 922, 1994. Frank, L. A., J. B. Sigwarth, Atmospheric holes and small comets, Rev. Geophys., 31, 1– 28, 1993. Frank, L. A., J. B. Sigwarth, Transient decreases of Earth's far ultraviolet dayglow, Geophys. Res. Lett., 24, 2423– 2426, 1997. Frank, L. A., J. B. Sigwarth, Detection of atomic oxygen trails of small comets in the vicinity of the Earth, J. Geophys. Res., 104, 115– 141, 1999. Frank, L. A., andJ. B. Sigwarth, Comment on “An optical search for small comets”, by R. L. Mutel and J. D. Fix,J. Geophys. Res., 106(A11)2001. Frank, L. A., J. B. Sigwarth, J. D. Craven, On the influx of small comets into the Earth's upper atmosphere, 1. Observations, Geophys. Res. Lett., 13, 303– 306, 1986. Frank, L. A., J. B. Sigwartlk, C. M. Yeates, A search for small solar-system bodies near the Earth using a ground-based telescope: Technique and observations, Astron. Astrophys., 228, 522– 530, 1990. Mutel, R. L., J. D. Fix, An optical search for small comets, J. Geophys. Res., 105, 24,907– 24,915, 2000. Yeates, C. M., Initial findings from a telescopic search for small comets near Earth, Planet. Space. Sci., 37, 1185– 1196, 1989. Citing Literature Volume106, IssueA111 November 2001Pages 24863-24868 ReferencesRelatedInformation RecommendedReply [to “Comment on “A search for small comets with the Naval Space Command Radar” by S. Knowles et al.”]S. Knowles, R. R. Meier, B. Å. S. Gustafson, F. J. Giovane, Journal of Geophysical Research: Space PhysicsAn optical search for small cometsR. L. Mutel, J. D. Fix, Journal of Geophysical Research: Space PhysicsReply to “Comment on ‘Reply’” by P. M. Aker et al.Pamela M. Aker, Journal of Geophysical Research: AtmospheresComment on “An optical search for small comets” by R. L. Mutel and J. D. FixL. A. Frank, J. B. Sigwarth, Journal of Geophysical Research: Space PhysicsReply to comment by R. L. Lysak on “Improved basis set for low frequency plasma waves”P. M. Bellan, Journal of Geophysical Research: Space Physics

MAJOR CONSTRAINTS ON THE USE OF RADIOCARBON DATING FOR TEPHROCHRONOLOGY

It is well recognised that radiocarbon dating is a powerful tool capable of providing a detailed chronostratigraphy for areas that have been subjected to recurrent volcanic activity during Late Pleistocene and Holocene time. In such geological contexts carbon-bearing materials suitable for 14 C dating are, for the most part, refractory components of pedosphere (e.g. paleosol humic matter) and organic detritus (e.g. charred/uncharred remains of higher plants) which occur within the tephra suites. Since such materials derive initially from atmospheric carbon dioxide, as well as record significant lapses in volcanic activity, it is then often assumed that these conditions comply ideally with the fundamental requirements of the radiocarbon dating theory. However, two recent 14 C dating programmes based on materials from the volcanic districts of the Phlegrean Fields and the island of Procida (Campania, southern Italy) yielded evidence to the contrary and, in turn, gave rise to concern over the validity of the 14 C dating method when applied in volcanic regions. In particular, it has been found that the conventional radiocarbon ages recorded by modern tree-leaves from the caldera of Solfatara volcano range from ‘modern’ to ca. 5000 yr BP. Furthermore, the magnitude of the age anomaly is determined by the pattern of localised dilution of the mean atmospheric 14 C concentration by juvenile ( 14 C-free and 13 C-enriched) carbon dioxide issuing from nearby volcanic vents. In the case of paleosols, a series of 14 C measurements on different chemical fractions isolated from the humic matter in a suite of four paleosol horizons entrained in tephra deposits at Procida island yielded, for each paleosol horizon, a systematic ca. 2000 yr scatter of 14 C ages. It is shown that such intra-soil age differences, which reflect the origin and history of humic constituents, can be used to afford a better definition of the true paleosol age.

High-temperature electric furnaces with heating blocks made of carbon-bearing composites

High-temperature (up to 2200°C) furnaces with blocks made of carbon-bearing materials can be operated either in vacuums up to 1.33 10−3 (10−5 mm Hg) or in gases that are inert to carbon (argon or nitrogen).

Pyrolytic technology for assembling refractory structures made of carbon-bearing materials

Pyrolytic technology for assembling refractory structures made of carbon-bearing materials

Changes in carbon isotope ratios in the late Permian recorded in therapsid tooth apatite

THE end of the Permian witnessed global extinctions of marine and terrestrial fauna1. As marine biogenic carbonate and atmospheric carbon dioxide are in long-term isotopic equilibrium, changes in carbon isotope ratios in marine carbonate strata should record changes that occurred at that time in atmospheric ratios; one might then expect a correlation between 13C/12C ratios in such marine sequences and those in terrestrial records that derive from carbon-bearing materials that incorporate atmospheric CO2. An example of the latter is fossil tooth apatite from herbivorous fauna. Correlations of this sort between marine and terrestrial records are, however, difficult to establish as they rely on particular characteristics of the isotope curves. Here we show that stable-carbon isotope ratios in tooth apatite from Diictodon (a mammal-like reptile), in the late Permian Lower Beaufort succession of the South African Karoo (∼260–245 Myr), show a progressive depletion in 13C that is very similar to trends in marine carbonates from late Permian deposits in Eurasia2–7. These results suggest that global changes in total biomass occurred towards the end of the Permian: primary production decreased and continental aridity increased8, leading to a depletion of 13C in atmospheric and oceanic CO2.

Conversion of high-phosphorus pig iron in large converters with the use of carbon-bearing materials

Conversion of high-phosphorus pig iron in large converters with the use of carbon-bearing materials

Use of carbon-bearing materials in two-bath furnaces

The Krivorozhstal combine developed a technology for using anthracite in the cold charge on two-bath furnaces in order to conserve pig iron. A feature of this technology is the order of the cold-charging of scrap, anthracite, and lime or limestone. The new technology was compared with conventional techniques to determine its efficiency. The saving in pig iron was 10-11 kg/ton steel. This technology was found to be effective for making ordinary-grade steels. Anthracite characteristics and technology parameters are given.

Contribution of metabolic carbon to mollusc and barnacle shell carbonate

Carbon in marine calcareous tests is not necessarily derived only from dissolved inorganic carbon (DIG) in ambient sea water; metabolic carbon can also be incorporated into carbonate tests, as shown by experiments using 14C-labelled food during the incubation of sea urchin embryos and coral1,2. 14C-rich organic matter (relative to seawater DIC) from terrestrial vegetation as well as marine organic matter (reflecting seawater DIC) is used as food by marine organisms in near-shore environments. This use provides the basis for a natural experiment on the systematics of metabolic carbon incorporation into carbonate tests. Here we have combined 14C/12C and 13C/12C ratio measurements on both the calcareous and the organic parts of marine organisms and on DIC, plankton and other carbon-bearing materials collected in and around New Haven Harbor (Connecticut, USA) in Long Island Sound, where the various sources of carbon can be identified, and we deduce that a large percentage of the carbon in calcareous tests is metabolic carbon. Thus, it is at best difficult to use the δ13C values of ancient biogenic carbonate from molluscs to predict the ancient δ13C values of seawater DIC

Some Influences of Carbon in Enameling of Steel

Analyses of the gases produced by carbon-bearing ferrous materials, fired in an oxidizing environment with or without enamel bisque, are correlated with the enameling properties and the microstructures of the materials. Total carbon content, or total volume of carbon oxides producible in designated circumstances, is not a reliable guide to enameling behavior form and distribution of the carbide phase are critically significant. A vacuum system for extraction and analysis of gases is described.