WorldWideScience

Sample records for fossil carbon contents

  1. Determination of fossil carbon content in Swedish waste fuel by four different methods.

    Science.gov (United States)

    Jones, Frida C; Blomqvist, Evalena W; Bisaillon, Mattias; Lindberg, Daniel K; Hupa, Mikko

    2013-10-01

    This study aimed to determine the content of fossil carbon in waste combusted in Sweden by using four different methods at seven geographically spread combustion plants. In total, the measurement campaign included 42 solid samples, 21 flue gas samples, 3 sorting analyses and 2 investigations using the balance method. The fossil carbon content in the solid samples and in the flue gas samples was determined using (14)C-analysis. From the analyses it was concluded that about a third of the carbon in mixed Swedish waste (municipal solid waste and industrial waste collected at Swedish industry sites) is fossil. The two other methods (the balance method and calculations from sorting analyses), based on assumptions and calculations, gave similar results in the plants in which they were used. Furthermore, the results indicate that the difference between samples containing as much as 80% industrial waste and samples consisting of solely municipal solid waste was not as large as expected. Besides investigating the fossil content of the waste, the project was also established to investigate the usability of various methods. However, it is difficult to directly compare the different methods used in this project because besides the estimation of emitted fossil carbon the methods provide other information, which is valuable to the plant owner. Therefore, the choice of method can also be controlled by factors other than direct determination of the fossil fuel emissions when considering implementation in the combustion plants.

  2. The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile - Marine sources and diagenetic effects.

    Directory of Open Access Journals (Sweden)

    Friedrich Lucassen

    Full Text Available Seabird excrements (guano have been preserved in the arid climate of Northern Chile since at least the Pliocene. The deposits of marine organic material in coastal areas potentially open a window into the present and past composition of the coastal ocean and its food web. We use the stable isotope composition of nitrogen and carbon as well as element contents to compare the principal prey of the birds, the Peruvian anchovy, with the composition of modern guano. We also investigate the impact of diagenetic changes on the isotopic composition and elemental contents of the pure ornithogenic sediments, starting with modern stratified deposits and extending to fossil guano. Where possible, 14C systematics is used for age information. The nitrogen and carbon isotopic composition of the marine prey (Peruvian anchovy of the birds is complex as it shows strong systematic variations with latitude. The detailed study of a modern profile that represents a few years of guano deposition up to present reveals systematic changes in nitrogen and carbon isotopic composition towards heavier values that increase with age, i.e. depth. Only the uppermost, youngest layers of modern guano show compositional affinity to the prey of the birds. In the profile, the simultaneous loss of nitrogen and carbon occurs by degassing, and non-volatile elements like phosphorous and calcium are passively enriched in the residual guano. Fossil guano deposits are very low in nitrogen and low in carbon contents, and show very heavy nitrogen isotopic compositions. One result of the study is that the use of guano for tracing nitrogen and carbon isotopic and elemental composition in the marine food web of the birds is restricted to fresh material. Despite systematic changes during diagenesis, there is little promise to retrieve reliable values of marine nitrogen and carbon signatures from older guano. However, the changes in isotopic composition from primary marine nitrogen isotopic

  3. Methodological comparison for quantitative analysis of fossil and recently derived carbon in mine soils with high content of aliphatic kerogen

    Czech Academy of Sciences Publication Activity Database

    Vindušková, O.; Sebag, D.; Cailleau, G.; Brus, Jiří; Frouz, J.

    89-90, December (2015), s. 14-22 ISSN 0146-6380 Institutional support: RVO:61389013 Keywords : kerogen * geogenic carbon * soil organic matter Subject RIV: DD - Geochemistry Impact factor: 2.990, year: 2015

  4. Carbon Risk and the Fossil Fuel Industry

    International Nuclear Information System (INIS)

    Mathieu, Carole

    2015-04-01

    As calls for ambitious climate action intensify, questions arise concerning the resilience of the fossil fuel industry in a world ever more inclined to favour climate protection. This article will attempt to assess the extent of present risks and show how the strength of debate can affect practices and strategy employed by companies in this sector. (author)

  5. Climate Policy and the Optimal Extraction of High- and Low-Carbon Fossil Fuels

    NARCIS (Netherlands)

    Smulders, J.A.; van der Werf, E.H.

    2005-01-01

    We study how restricting CO2 emissions affcts resource prices and depletion over time.We use a Hotelling-style model with two nonrenewable fossil fuels that differ in their carbon content (e.g. coal and natural gas) and that are imperfect substitutes in final good production.We study both an

  6. Carbon dioxide from fossil fuels: adapting to uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Chen, K; Winter, R C; Bergman, M K

    1980-12-01

    If present scientific information is reasonable, the world is likely to experience noticeable global warming by the beginning of the next century if high annual growth rates of fossil-fuel energy use continue. Only with optimistic assumptions and low growth rates will carbon-dioxide-induced temperature increases be held below 2/sup 0/C or so over the next century. Conservation, flexible energy choices, and control options could lessen the potential effects of carbon dioxide. Though perhaps impractical from the standpoint of costs and efficiency losses, large coastal centralized facilities would be the most amenable to carbon dioxide control and disposal. Yet no country can control carbon dioxide levels unilaterally. The USA, however, which currently contributes over a quarter of all fossil-fuel carbon dioxide emissions and possesses a quarter of the world's coal resources, could provide a much needed role in leadership, research and education. 70 references.

  7. Cumulative emissions, unburnable fossil fuel, and the optimal carbon tax

    NARCIS (Netherlands)

    van der Ploeg, F.; Rezai, A.

    2017-01-01

    A stylised analytical framework is used to show how the global carbon tax and the amount of untapped fossil fuel can be calculated from a simple rule given estimates of society's rate of time impatience and intergenerational inequality aversion, the extraction cost technology, the rate of technical

  8. Fossil and non-fossil sources of organic carbon (OC and elemental carbon (EC in Göteborg, Sweden

    Directory of Open Access Journals (Sweden)

    S. Szidat

    2009-03-01

    Full Text Available Particulate matter was collected at an urban site in Göteborg (Sweden in February/March 2005 and in June/July 2006. Additional samples were collected at a rural site for the winter period. Total carbon (TC concentrations were 2.1–3.6 μg m−3, 1.8–1.9 μg m−3, and 2.2–3.0 μg m−3 for urban/winter, rural/winter, and urban/summer conditions, respectively. Elemental carbon (EC, organic carbon (OC, water-insoluble OC (WINSOC, and water-soluble OC (WSOC were analyzed for 14C in order to distinguish fossil from non-fossil emissions. As wood burning is the single major source of non-fossil EC, its contribution can be quantified directly. For non-fossil OC, the wood-burning fraction was determined independently by levoglucosan and 14C analysis and combined using Latin-hypercube sampling (LHS. For the winter period, the relative contribution of EC from wood burning to the total EC was >3 times higher at the rural site compared to the urban site, whereas the absolute concentrations of EC from wood burning were elevated only moderately at the rural compared to the urban site. Thus, the urban site is substantially more influenced by fossil EC emissions. For summer, biogenic emissions dominated OC concentrations most likely due to secondary organic aerosol (SOA formation. During both seasons, a more pronounced fossil signal was observed for Göteborg than has previously been reported for Zurich, Switzerland. Analysis of air mass origin using back trajectories suggests that the fossil impact was larger when local sources dominated, whereas long-range transport caused an enhanced non-fossil signal. In comparison to other European locations, concentrations of levoglucosan and other monosaccharide anhydrides were low for the urban and the rural site in the area of Göteborg during winter.

  9. Global change: The new challenge for the fossil carbon industries

    International Nuclear Information System (INIS)

    Fyfe, W.S.

    1991-01-01

    Human population growth, at 90 million more per year and at least 10 billion next century, is forcing a re-examination of our values and technologies. Technology concerns are energy, food production, water and air quality, and waste disposal. All of these involve exact knowledge of the outer few km of our planet because this film forms the basis of all our resources. A great new challenge faces people with expertise in the fine structure and dynamics of the porous-cracked outer layers of earth. Much of this expertise is centered in the fossil carbon industries. All must be involved in the problems of water supply, soil conservation, waste disposal, and clean energy production. Perhaps the greatest question facing the fossil fuel industry concerns whether greenhouse gas emissions can be reduced

  10. Fossil fuel derivatives with reduced carbon. Phase I final report

    Energy Technology Data Exchange (ETDEWEB)

    Kennel, E.B.; Zondlo, J.W.; Cessna, T.J.

    1999-06-30

    This project involves the simultaneous production of clean fossil fuel derivatives with reduced carbon and sulfur, along with value-added carbon nanofibers. This can be accomplished because the nanofiber production process removes carbon via a catalyzed pyrolysis reaction, which also has the effect of removing 99.9% of the sulfur, which is trapped in the nanofibers. The reaction is mildly endothermic, meaning that net energy production with real reductions in greenhouse emissions are possible. In Phase I research, the feasibility of generating clean fossil fuel derivatives with reduced carbon was demonstrated by the successful design, construction and operation of a facility capable of utilizing coal as well as natural gas as an inlet feedstock. In the case of coal, for example, reductions in CO{sub 2} emissions can be as much as 70% (normalized according to kilowatts produced), with the majority of carbon safely sequestered in the form of carbon nanofibers or coke. Both of these products are value-added commodities, indicating that low-emission coal fuel can be done at a profit rather than a loss as is the case with most clean-up schemes. The main results of this project were as follows: (1) It was shown that the nanofiber production process produces hydrogen as a byproduct. (2) The hydrogen, or hydrogen-rich hydrocarbon mixture can be consumed with net release of enthalpy. (3) The greenhouse gas emissions from both coal and natural gas are significantly reduced. Because coal consumption also creates coke, the carbon emission can be reduced by 75% per kilowatt-hour of power produced.

  11. Monthly, global emissions of carbon dioxide from fossil fuel consumption

    DEFF Research Database (Denmark)

    Andres, R.J.; Gregg, Jay Sterling; Losey, L.

    2011-01-01

    This paper examines available data, develops a strategy and presents a monthly, global time series of fossil-fuel carbon dioxide emissions for the years 1950–2006. This monthly time series was constructed from detailed study of monthly data from the 21 countries that account for approximately 80......% of global total emissions. These data were then used in a Monte Carlo approach to proxy for all remaining countries. The proportional-proxy methodology estimates by fuel group the fraction of annual emissions emitted in each country and month. Emissions from solid, liquid and gas fuels are explicitly...

  12. Carbon dioxide from fossil fuels. Adapting to uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Chen, K; Winter, R C; Bergman, M K

    1980-12-01

    The world is likely to experience noticeable carbon dioxide induced global warming by the beginning of the next century if high annual growth rates of fossil fuel energy use continue. This article proposes some ideas about what can be done from a policy-making perspective if the CO$SUB$2 effects occur, and how, in addition, we can deal now with the uncertainties. It also considers questions concerning the potential for control of CO$SUB$2 emissions drawing up on current work in long range coal-based energy technology assessment. (70 refs.)

  13. Climate policy and the optimal extraction of high- and low-carbon fossil fuels

    International Nuclear Information System (INIS)

    Smulders, S.; Van der Werf, E.

    2005-01-01

    We study how restricting CO2 emissions affects resource prices and depletion over time. We use a Hotelling-style model with two non- renewable fossil fuels that differ in their carbon content (e.g. coal and natural gas) and that are imperfect substitutes in final good production. We study both an unexpected constraint and an anticipated constraint. Both shocks induce intertemporal substitution of resource use. When emissions are unexpectedly restricted, it is cost-effective to use high-carbon resources relatively more (less) intensively on impact if this resource is relatively scarce (abundant). If the emission constraint is anticipated, it is cost-effective to use relatively more (less) of the low-carbon input before the constraint becomes binding, in order to conserve relatively more (less) of the high-carbon input for the period when climate policy is active in case the high-carbon resource is relatively scarce (abundant)

  14. Uranium content and U-Th dating of fossil bones and dental tissues from Lazaret cave

    International Nuclear Information System (INIS)

    Michel, V.; Falgueres, Ch.; Yokoyama, Y.

    1997-01-01

    Fossil bone and dental tissues from Lazaret cave and modern ones are here the subject of a comparative microscopical study. Porous tissues such as dentine and bone have retained their Haversian and Tomes canals respectively. However, cracked areas with calcite were detected, indicating a water percolation within porous tissues and an alteration of tissue in places. In addition, compact fossil enamel is particularly well preserved. These results are essential for U-Tb and ESR dating application. Uranium contents, U-Tb ages of two fossil mandibular tissues, two tibias and of six burnt fossil bones are presented and discussed. (authors)

  15. Vanadium contents in Kazakhstan fossils hydrocarbons by data of nuclear-physical analysis methods

    International Nuclear Information System (INIS)

    Nadirov, N.K.; Solodukhin, V.P.

    1998-01-01

    Investigation of nuclear physical methods possibilities of vanadium determination analysis in organic fossils and an application of these methods for solution of scientific and practical tasks are presented. Vanadium contents in high viscous petroleums and petroleum bituminous rock of different deposits of Western Kazakhstan and carbonaceous shales of Dzhangariya are studied. Presented data evidence that organic fossils of numerous deposits of Kazakhstan have industrial interest because of high vanadium concentration in its contents

  16. Monthly, global emissions of carbon dioxide from fossil fuel consumption

    Energy Technology Data Exchange (ETDEWEB)

    Andres, R. J.; Marland, G.; Boden, T. A. (Environmental Sciences Div., Oak Ridge National Laboratory, Oak Ridge, TN (United States)), e-mail: andresrj@ornl.gov; Gregg, J. S. (Risoe DTU National Laboratory for Sustainable Energy, Roskilde (Denmark)); Losey, L. (Dept. of Space Studies, Univ. of North Dakota, Grand Forks, ND (United States))

    2011-07-15

    This paper examines available data, develops a strategy and presents a monthly, global time series of fossil-fuel carbon dioxide emissions for the years 1950-2006. This monthly time series was constructed from detailed study of monthly data from the 21 countries that account for approximately 80% of global total emissions. These data were then used in a Monte Carlo approach to proxy for all remaining countries. The proportional-proxy methodology estimates by fuel group the fraction of annual emissions emitted in each country and month. Emissions from solid, liquid and gas fuels are explicitly modelled by the proportional-proxy method. The primary conclusion from this study is the global monthly time series is statistically significantly different from a uniform distribution throughout the year. Uncertainty analysis of the data presented show that the proportional-proxy method used faithfully reproduces monthly patterns in the data and the global monthly pattern of emissions is relatively insensitive to the exact proxy assignments used. The data and results presented here should lead to a better understanding of global and regional carbon cycles, especially when the mass data are combined with the stable carbon isotope data in atmospheric transport models

  17. Fossil organic carbon in wastewater and its fate in treatment plants.

    Science.gov (United States)

    Law, Yingyu; Jacobsen, Geraldine E; Smith, Andrew M; Yuan, Zhiguo; Lant, Paul

    2013-09-15

    This study reports the presence of fossil organic carbon in wastewater and its fate in wastewater treatment plants. The findings pinpoint the inaccuracy of current greenhouse gas accounting guidelines which defines all organic carbon in wastewater to be of biogenic origin. Stable and radiocarbon isotopes ((13)C and (14)C) were measured throughout the process train in four municipal wastewater treatment plants equipped with secondary activated sludge treatment. Isotopic mass balance analyses indicate that 4-14% of influent total organic carbon (TOC) is of fossil origin with concentrations between 6 and 35 mg/L; 88-98% of this is removed from the wastewater. The TOC mass balance analysis suggests that 39-65% of the fossil organic carbon from the influent is incorporated into the activated sludge through adsorption or from cell assimilation while 29-50% is likely transformed to carbon dioxide (CO2) during secondary treatment. The fossil organic carbon fraction in the sludge undergoes further biodegradation during anaerobic digestion with a 12% decrease in mass. 1.4-6.3% of the influent TOC consists of both biogenic and fossil carbon is estimated to be emitted as fossil CO2 from activated sludge treatment alone. The results suggest that current greenhouse gas accounting guidelines, which assume that all CO2 emission from wastewater is biogenic may lead to underestimation of emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Carbon dioxide emissions from fossil fuel use: Recent performance and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, Michael

    1998-12-01

    This publication gives an overview and discusses carbon dioxide emissions from fossil fuel use worldwide. Main themes discussed in this connection cover recent performance and future prospects. Some proposals on the reduction of CO{sub 2} emissions are given

  19. A synthesis of carbon dioxide emissions from fossil-fuel combustion

    DEFF Research Database (Denmark)

    Andres, R.J.; Boden, T.A.; Bréon, F.-M.

    2012-01-01

    This synthesis discusses the emissions of carbon dioxide from fossil-fuel combustion and cement production. While much is known about these emissions, there is still much that is unknown about the details surrounding these emissions. This synthesis explores our knowledge of these emissions in terms......; and the uncertainties associated with these different aspects of the emissions. The magnitude of emissions from the combustion of fossil fuels has been almost continuously increasing with time since fossil fuels were first used by humans. Despite events in some nations specifically designed to reduce emissions......, or which have had emissions reduction as a byproduct of other events, global total emissions continue their general increase with time. Global total fossilfuel carbon dioxide emissions are known to within 10% uncertainty (95% confidence interval). Uncertainty on individual national total fossil-fuel carbon...

  20. The European carbon balance. Part 1: fossil fuel emissions

    NARCIS (Netherlands)

    Ciais, P.; Paris, J.D.; Marland, G.; Peylin, P.; Piao, S.L.; levin, I.; Pregger, T.; Scholz, Y.; Friedrich, R.; Rivier, L.; Houweling, S.; Schulze, E.D.

    2010-01-01

    We analyzed the magnitude, the trends and the uncertainties of fossil-fuel CO2 emissions in the European Union 25 member states (hereafter EU-25), based on emission inventories from energy-use statistics. The stability of emissions during the past decade at EU-25 scale masks decreasing trends in

  1. Fossil and Contemporary Fine Carbon Fractions at 12 Rural and Urban Sites in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Schichtel, B; Malm, W; Bench, G; Fallon, S; McDade, C; Chow, J

    2007-03-01

    Fine particulate matter collected at two urban, four near-urban, and six remote sites throughout the United States were analyzed for total carbon (TC) and radiocarbon ({sup 14}C). Samples were collected at most sites for both a summer and winter season. The radiocarbon was used to partition the TC into fossil and contemporary fractions. On average, contemporary carbon composed about half of the carbon at the urban, {approx}70-97% at near-urban, and 82-100% at remote sites. At Phoenix, Arizona, and Seattle, Washington, one monitor was located within the urban center and one outside to assess the urban excess over background concentrations. During the summer the urban and rural sites had similar contemporary carbon concentrations. However, during the winter the urban sites had more than twice the contemporary carbon measured at the neighboring sites, indicating anthropogenic contributions to the contemporary carbon. The urban fossil carbon was 4-20 times larger than the neighboring rural sites for both seasons. Organic (OC) and elemental carbon (EC) from TOR analysis were available. These and the radiocarbon data were used to estimate characteristic fossil and contemporary EC/TC ratios for the winter and summer seasons. These ratios were applied to carbon data from the Interagency Monitoring of Protected Visual Environments network to estimate the fraction of contemporary carbon at mostly rural sites throughout the United States. In addition, the ratios were used to develop a semiquantitative, lower bound estimate of secondary organic carbon (SOC) contribution to fossil and contemporary carbon. SOC accounted for more than one-third of the fossil and contemporary carbon.

  2. First report of fossil "keratose" demosponges in Phanerozoic carbonates: preservation and 3-D reconstruction.

    Science.gov (United States)

    Luo, Cui; Reitner, Joachim

    2014-06-01

    Fossil record of Phanerozoic non-spicular sponges, beside of being important with respect to the lineage evolution per se, could provide valuable references for the investigation of Precambrian ancestral animal fossils. However, although modern phylogenomic studies resolve non-spicular demosponges as the sister group of the remaining spiculate demosponges, the fossil record of the former is extremely sparse or unexplored compared to that of the latter; the Middle Cambrian Vauxiidae Walcott 1920, is the only confirmed fossil taxon of non-spicular demosponges. Here, we describe carbonate materials from Devonian (Upper Givetian to Lower Frasnian) bioherms of northern France and Triassic (Anisian) microbialites of Poland that most likely represent fossil remnants of keratose demosponges. These putative fossils of keratose demosponges are preserved as automicritic clumps. They are morphologically distinguishable from microbial fabrics but similar to other spiculate sponge fossils, except that the skeletal elements consist of fibrous networks instead of assembled spicules. Consistent with the immunological behavior of sponges, these fibrous skeletons often form a rim at the edge of the automicritic aggregate, separating the inner part of the aggregate from foreign objects. To confirm the architecture of these fibrous networks, two fossil specimens and a modern thorectid sponge for comparison were processed for three-dimensional (3-D) reconstruction using serial grinding tomography. The resulting fossil reconstructions are three-dimensionally anastomosing, like modern keratose demosponges, but their irregular and nonhierarchical meshes indicate a likely verongid affinity, although a precise taxonomic conclusion cannot be made based on the skeletal architecture alone. This study is a preliminary effort, but an important start to identify fossil non-spicular demosponges in carbonates and to re-evaluate their fossilization potential.

  3. The Seasonal and Spatial Distribution of Carbon Dioxide Emissions from Fossil Fuels in Asia

    Science.gov (United States)

    Gregg, J. S.; Andres, R. J.

    2006-12-01

    Carbon dioxide emissions from fossil-fuel consumption are presented for the five Asian countries that are among the global leaders in anthropogenic carbon emissions: China (13% of global total), Japan (5% of global total), India (5% of global total), South Korea (2% of global total), and Indonesia (1% of global total). Together, these five countries represent over a quarter of the world's fossil-fuel based carbon emissions. Moreover, these countries are rapidly developing and energy demand has grown dramatically in the last two decades. A method is developed to estimate the spatial and seasonal flux of fossil-fuel consumption, thereby greatly improving the temporal and spatial resolution of anthropogenic carbon dioxide emissions. Currently, only national annual data for anthropogenic carbon emissions are available, and as such, no understanding of seasonal or sub-national patterns of emissions are possible. This methodology employs fuel distribution data from representative sectors of the fossil-fuel market to determine the temporal and spatial patterns of fuel consumption. These patterns of fuel consumption are then converted to patterns of carbon emissions. The annual total emissions estimates produced by this method are consistent to those maintained by the United Nations. Improved estimates of temporal and spatial resolution of the human based carbon emissions allows for better projections about future energy demands, carbon emissions, and ultimately the global carbon cycle.

  4. A synthesis of carbon dioxide emissions from fossil-fuel combustion

    Directory of Open Access Journals (Sweden)

    R. J. Andres

    2012-05-01

    Full Text Available This synthesis discusses the emissions of carbon dioxide from fossil-fuel combustion and cement production. While much is known about these emissions, there is still much that is unknown about the details surrounding these emissions. This synthesis explores our knowledge of these emissions in terms of why there is concern about them; how they are calculated; the major global efforts on inventorying them; their global, regional, and national totals at different spatial and temporal scales; how they are distributed on global grids (i.e., maps; how they are transported in models; and the uncertainties associated with these different aspects of the emissions. The magnitude of emissions from the combustion of fossil fuels has been almost continuously increasing with time since fossil fuels were first used by humans. Despite events in some nations specifically designed to reduce emissions, or which have had emissions reduction as a byproduct of other events, global total emissions continue their general increase with time. Global total fossil-fuel carbon dioxide emissions are known to within 10 % uncertainty (95 % confidence interval. Uncertainty on individual national total fossil-fuel carbon dioxide emissions range from a few percent to more than 50 %. This manuscript concludes that carbon dioxide emissions from fossil-fuel combustion continue to increase with time and that while much is known about the overall characteristics of these emissions, much is still to be learned about the detailed characteristics of these emissions.

  5. Wood-energy: success depends on the price of fossil energies and on the carbon tax level

    International Nuclear Information System (INIS)

    Defaye, Serge; Maindrault, Marc

    2016-01-01

    Illustrated by several graphs indicating the structure of fossil energy prices, the comparison between domestic fuel and wood-energy for public network exploitation, the levels of fossil prices and carbon tax for non-subsidised projects, this article analyses the development of biomass (and more particularly wood-energy), the success of which depends on the price of fossil energies and on the carbon tax level. It outlines the differences of price-building elements between fossil and renewable heat, that subsidies are necessary if reference prices are low. It discusses the influence of carbon tax level and of fossil prices. It finally identifies conditions to be met (reduction of fossil energy supply and therefore higher fossil prices, introduction of a carbon tax) to reach COP objectives

  6. Formulating Energy Policies Related to Fossil Fuel Use: Critical Uncertainties in the Global Carbon Cycle

    Science.gov (United States)

    Post, W. M.; Dale, V. H.; DeAngelis, D. L.; Mann, L. K.; Mulholland, P. J.; O`Neill, R. V.; Peng, T. -H.; Farrell, M. P.

    1990-02-01

    The global carbon cycle is the dynamic interaction among the earth's carbon sources and sinks. Four reservoirs can be identified, including the atmosphere, terrestrial biosphere, oceans, and sediments. Atmospheric CO{sub 2} concentration is determined by characteristics of carbon fluxes among major reservoirs of the global carbon cycle. The objective of this paper is to document the knowns, and unknowns and uncertainties associated with key questions that if answered will increase the understanding of the portion of past, present, and future atmospheric CO{sub 2} attributable to fossil fuel burning. Documented atmospheric increases in CO{sub 2} levels are thought to result primarily from fossil fuel use and, perhaps, deforestation. However, the observed atmospheric CO{sub 2} increase is less than expected from current understanding of the global carbon cycle because of poorly understood interactions among the major carbon reservoirs.

  7. Interaction of carbon reduction and green energy promotion in a small fossil-fuel importing economy

    International Nuclear Information System (INIS)

    Pethig, Ruediger; Wittlich, Christian

    2009-01-01

    We study the incidence of carbon-reduction and green-energy promotion policies in an open fossil-fuel importing general equilibrium economy. The focus is on mixed price-based or quantity-based policies. Instruments directed toward promoting green energy are shown to reduce also carbon emissions and vice versa. Their direct effects are stronger than their side effects, the more so, the greater is the elasticity of substitution in consumption between energy and the consumption good. We calculate the effects of variations in individual policy parameters, especially on energy prices and welfare costs, and determine the impact of exogenous fossil-fuel price shocks on the economy. (orig.)

  8. Reduced carbon emission estimates from fossil fuel combustion and cement production in China

    OpenAIRE

    Liu, Zhu; Guan, Dabo; Wei, Wei; Davis, Steven J.; Ciais, Philippe; Bai, Jin; Peng, Shushi; Zhang, Qiang; Hubacek, Klaus; Garland, Gregg; Andres, Robert J.; Crawford-Brown, Douglas; Lin, Jintai; Zhao, Hongyan; Hong, Chaopeng

    2015-01-01

    This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/nature14677 Nearly three-quarters of the growth in global carbon emission from burning of fossil fuels and cement production between 2010 and 2012 occurred in China. Yet estimates of Chinese emissions remain subject to large uncertainty; inventories of China's total fossil fuel carbon emissions in 2008 varied by 0.3 GtC, or 15 per cent. The primary sources of this uncertainty are c...

  9. Carbon isotopic composition of fossil leaves from the Early ...

    Indian Academy of Sciences (India)

    considerable variation in carbon isotopic composition. The Trambau ... One of the most significant changes in the ocean atmosphere .... cryogenic separation of water, CO2 was dynami- .... light condition, nutrients and temperature are low,.

  10. Fossil and nonfossil carbon in fine particulate matter: A study of five European cities

    Science.gov (United States)

    Glasius, Marianne; La Cour, Agnete; Lohse, Christian

    2011-06-01

    Fossil carbon in particulate matter comes from anthropogenic use and combustion of fossil fuels, while nonfossil carbon may originate from both biogenic (e.g., pollen, plant debris, fungal spores, and biogenic secondary organic aerosol (SOA)) and anthropogenic sources (e.g., cooking and residential wood combustion). We investigated the relative contributions of fossil and nonfossil sources to fine carbonaceous aerosols in five European cities by radiocarbon analysis of aerosol samples collected at four types of sites in 2002-2004. The average fraction of nonfossil carbon was 43 ± 11%, with the lowest fraction, 36 ± 7%, at urban curbside sites and the highest fraction, 54 ± 11%, at rural background sites, farthest away from the impact of man-made emissions. Generally, fossil carbon concentrations at urban curbside sites are elevated in comparison to background sites, which is expected because of their proximity to vehicular emissions. Contrary to what might be expected, the concentration of nonfossil carbon is also higher at curbside than at background sites. This may be attributable to differences between site categories in levels of primary biological aerosols, brake and tire wear in resuspended road dust, biofuels, emissions from cooking and residential wood combustion, or processes such as anthropogenic enhancement of biogenic SOA and increased partitioning of semivolatile compounds into the aerosol phase at urban sites. The exact causes should be investigated by future detailed source analyses.

  11. Long-term ocean oxygen depletion in response to carbon dioxide emissions from fossil fuels

    DEFF Research Database (Denmark)

    Shaffer, G.; Olsen, S.M.; Pedersen, Jens Olaf Pepke

    2009-01-01

    Ongoing global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide from fossil-fuel burning from the atmosphere(1-3). Future warming may have large global impacts including ocean oxygen depletion and assoc......Ongoing global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide from fossil-fuel burning from the atmosphere(1-3). Future warming may have large global impacts including ocean oxygen depletion...... solubility from surface-layer warming accounts for most of the enhanced oxygen depletion in the upper 500 m of the ocean. Possible weakening of ocean overturning and convection lead to further oxygen depletion, also in the deep ocean. We conclude that substantial reductions in fossil-fuel use over the next...

  12. Organic carbon content of tropical zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.

    In the Zuari and Mandovi estuaries variations in organic carbon of zooplankton are 26.4-38.8 and 24-39.9% of dry weight respectively. Maximum carbon content of estuarine zooplankton is observed in November. Organic carbon in nearshore and oceanic...

  13. Uranium contents and 234U/238U activity ratios of modern and fossil marine bivalle molluscan shells

    International Nuclear Information System (INIS)

    Mitsuda, Hiroshi

    1984-01-01

    Uranium contents and 234 U/ 238 U activity ratios in modern and fossil marine bivalle molluscan shells were measured by alpha-spectrometry. Uranium contents and 234 U/ 238 U activity ratios in modern shells were averaged to be 0.266 (dpm/g), and 1.18, respectively and those in fossil shells were averaged to be 0.747 (dpm/g), and 1.19, respectivily. Uranium contents in fossil shells were obviously higher than those in modern shells. It can be explained by the addition of uranium to shell during the deposition. In fossil shells, 234 U/ 238 U activity ratio decreases as 238 U content increases the same tendency is not found in modern shells. The author proposed a mechanism of selective loss of 238 U from the fossil shells for the explanation of this tendency. The height activity ratio of 234 U/ 238 U measured on the fossil shells than that measured on the modern shells, also support the selective loss of 238 U from the fossil shells. (author)

  14. Carbon Monitoring System Flux for Fossil Fuel L4 V1 (CMSFluxFossilfuel) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset provides the Carbon Flux for Fossil Fuel. The NASA Carbon Monitoring System (CMS) is designed to make significant contributions in characterizing,...

  15. A new evaluation of the uncertainty associated with CDIAC estimates of fossil fuel carbon dioxide emission

    Directory of Open Access Journals (Sweden)

    Robert J. Andres

    2014-07-01

    Full Text Available Three uncertainty assessments associated with the global total of carbon dioxide emitted from fossil fuel use and cement production are presented. Each assessment has its own strengths and weaknesses and none give a full uncertainty assessment of the emission estimates. This approach grew out of the lack of independent measurements at the spatial and temporal scales of interest. Issues of dependent and independent data are considered as well as the temporal and spatial relationships of the data. The result is a multifaceted examination of the uncertainty associated with fossil fuel carbon dioxide emission estimates. The three assessments collectively give a range that spans from 1.0 to 13% (2 σ. Greatly simplifying the assessments give a global fossil fuel carbon dioxide uncertainty value of 8.4% (2 σ. In the largest context presented, the determination of fossil fuel emission uncertainty is important for a better understanding of the global carbon cycle and its implications for the physical, economic and political world.

  16. Reduced carbon emission estimates from fossil fuel combustion and cement production in China.

    Science.gov (United States)

    Liu, Zhu; Guan, Dabo; Wei, Wei; Davis, Steven J; Ciais, Philippe; Bai, Jin; Peng, Shushi; Zhang, Qiang; Hubacek, Klaus; Marland, Gregg; Andres, Robert J; Crawford-Brown, Douglas; Lin, Jintai; Zhao, Hongyan; Hong, Chaopeng; Boden, Thomas A; Feng, Kuishuang; Peters, Glen P; Xi, Fengming; Liu, Junguo; Li, Yuan; Zhao, Yu; Zeng, Ning; He, Kebin

    2015-08-20

    Nearly three-quarters of the growth in global carbon emissions from the burning of fossil fuels and cement production between 2010 and 2012 occurred in China. Yet estimates of Chinese emissions remain subject to large uncertainty; inventories of China's total fossil fuel carbon emissions in 2008 differ by 0.3 gigatonnes of carbon, or 15 per cent. The primary sources of this uncertainty are conflicting estimates of energy consumption and emission factors, the latter being uncertain because of very few actual measurements representative of the mix of Chinese fuels. Here we re-evaluate China's carbon emissions using updated and harmonized energy consumption and clinker production data and two new and comprehensive sets of measured emission factors for Chinese coal. We find that total energy consumption in China was 10 per cent higher in 2000-2012 than the value reported by China's national statistics, that emission factors for Chinese coal are on average 40 per cent lower than the default values recommended by the Intergovernmental Panel on Climate Change, and that emissions from China's cement production are 45 per cent less than recent estimates. Altogether, our revised estimate of China's CO2 emissions from fossil fuel combustion and cement production is 2.49 gigatonnes of carbon (2 standard deviations = ±7.3 per cent) in 2013, which is 14 per cent lower than the emissions reported by other prominent inventories. Over the full period 2000 to 2013, our revised estimates are 2.9 gigatonnes of carbon less than previous estimates of China's cumulative carbon emissions. Our findings suggest that overestimation of China's emissions in 2000-2013 may be larger than China's estimated total forest sink in 1990-2007 (2.66 gigatonnes of carbon) or China's land carbon sink in 2000-2009 (2.6 gigatonnes of carbon).

  17. Determination of low carbon content in uranium

    International Nuclear Information System (INIS)

    Champeix, L.; Chevilliard, H.; Ponty, J.

    1960-01-01

    The method of carbon determination previously used for low carbon steels has been applied to uranium. Carbon contents down to a few tens p.p.m. and probably to a few p.p.m., can be determined with satisfactory precision, sensibility and accuracy. Reprint of a paper published in 'Memoires Scientifiques Rev. Metallurg.', LVI, n. 7, 1959, p. 657-662 [fr

  18. Carbon, chromium and molybdenum contents

    International Nuclear Information System (INIS)

    Sinatora, A; Goldenstein, H.; Mei, P.R.; Albertin, E.; Fuoco, R.; Mariotto, C.L.

    1992-01-01

    This work describes solidification experiments on white cast iron, with 15 and 20% of chromium, 2.3, 3.0 and 3.6 % of carbon and 0.0, 1.5 and 2.5 % of molybdenum in test de samples with 30 mm diameter. Measurements were performed on the austenite and eutectic formation arrests, the number of the eutectic carbide particles relative to the total and the eutectic volumes, and the volume fraction of the primary austenite

  19. A WELL PRESERVED SKELETON OF THE FOSSIL SHARK COSMOPOLITODUS HASTALIS FROM THE LATE MIOCENE OF PERU, FEATURING FISH REMAINS AS FOSSILIZED STOMACH CONTENTS

    Directory of Open Access Journals (Sweden)

    ALBERTO COLLARETA

    2017-01-01

    Full Text Available Both the preservation of the poorly mineralized skeleton of sharks and the preservation of stomach contents are rarely observed in the fossil record. Here we report on a partial skeleton of a lamniform shark, including portions of the visceral arches and the anterior segment of the vertebral column, collected from the late Miocene beds of the Pisco Formation exposed at Cerro Yesera (Ica Desert, South Peru. Based on the morphology of the preserved teeth, this specimen was determined as a juvenile of the extinct lamnid species Cosmopolitodus hastalis. The shark skeleton includes remains of fish (featuring a pilchard determined as Sardinops sp. cf. S. sagax in the abdominal region. These fish remains are interpreted herein as the fossilized stomach contents of the shark. For the first time, piscivory is demonstrated in a juvenile individual of Cosmopolitodus hastalis. This result is consistent with the current knowledge about the feeding habits of immature individuals of extant lamniform shark species (including Carcharodon carcharias and Isurus oxyrinchus. Our report further outlines the fundamental role of schooling pilchards in the late Miocene trophic chains of the highly productive coastal waters off present South Peru. Moreover, the find of this well preserved shark skeleton strengthens the qualification of the Pisco Formation as a Fossil-Lagerstätte, and emphasizes the role of early mineralization processes in cases of exceptional preservation.

  20. The impact for households of a carbon component in the price of fossil energies

    International Nuclear Information System (INIS)

    Simon, Olivier; Thao Khamsing, Willy

    2016-03-01

    A carbon component has been introduced in tax on fossil energies in 2014 in France in order to support energy transition, and resulted in a higher cost of fossil energies for households in their transport and heating expenses. This publication aims at illustrating and commenting these consequences of a carbon component. It shows that expenses increase with the standard of living, that modest households are more affected, notably as far as heating expenses are concerned, that households using domestic fuel for heating and diesel fuel for their vehicles are the most affected, that the additional cost is particularly a burden for single-parent families and singles, and that rural households are more affected. A cross-criterion analysis (household type, location, heating type, fuel type) is proposed to assess the impact of 2016 on the energy bill of typical households. Methodological hypotheses, data origins and calculation method are briefly presented

  1. Carbon dioxide emissions from fossil-fuel use, 1751-1950

    Energy Technology Data Exchange (ETDEWEB)

    Andres, R.J.; Fielding, D.J.; Marland, G.; Boden, T.A.; Kumar, N.; Kearney, A.T. [University of Alaska, Fairbanks, AK (US). Inst. of Northern Engineering

    1999-09-01

    Newly compiled energy statistics allow the complete time series of carbon dioxide (CO{sub 2}) emissions from fossil-fuel use for the years 1751 to the present to be estimated. The time series begins with 3 x 10{sup 6} metric tonnes carbon (C). The CO{sub 2} flux increased exponentially until World War I. The time series derived here seamlessly joins the modern 1950 to present time series. Total cumulative CO{sub 2} emissions through 1949 were 61.0 x 10{sup 9} tonne C from fossil-fuel use, virtually all since the beginning of the Industrial Revolution around 1860. The rate of growth continues to grow during present times, generating debate on the probability of enhanced greenhouse warming. In addition to global totals, national totals and 1 degree global distributions of the data have been calculated.

  2. Improved Fossil/Industrial CO2 Emissions Modeling for the North American Carbon Program

    Science.gov (United States)

    Gurney, K. R.; Seib, B.; Mendoza, D.; Knox, S.; Fischer, M.; Murtishaw, S.

    2006-12-01

    The quantification of fossil fuel CO2 emissions has implications for a wide variety of scientific and policy- related questions. Improvement in inverse-estimated carbon fluxes, country-level carbon budgeting, analysis of regional emissions trading systems, and targeting of observational systems are all important applications better served by improvements in understanding where and when fossil fuel/industrial CO2 is emitted. Traditional approaches to quantifying fossil/industrial CO2 emissions have relied on national sales/consumption of fossil fuels with secondary spatial footprints performed via proxies such as population. This approach has provided global spatiotemporal resolution of one degree/monthly. In recent years the need has arisen for emission estimates that not only achieve higher spatiotemporal scales but include a process- level component. This latter attribute provides dynamic linkages between energy policy/decisionmaking and emissions for use in projecting changes to energy systems and the implications these changes may have on climate change. We have embarked on a NASA-funded research strategy to construct a process-level fossil/industrial CO2 emissions model/database for North America that will resolve fossil/industrial CO2 emissions hourly and at 36 km. This project is a critical component of the North American Carbon Program. Our approach builds off of many decades of air quality monitoring for regulated pollutants such as NOx, VOCs and CO that has been performed by regional air quality managers, states, and the Environmental Protection Agency in the United States. By using the highly resolved monitoring data supplied to the EPA, we have computed CO2 emissions for residential, commercial/industrial, transportation, and biogenic sources. This effort employs a new emissions modeling system (CONCEPT) that spatially and temporally distributes the monitored emissions across the US. We will provide a description of the methodology we have employed, the

  3. Carbon fiber content measurement in composite

    Science.gov (United States)

    Wang, Qiushi

    Carbon fiber reinforced polymers (CFRPs) have been widely used in various structural applications in industries such as aerospace and automotive because of their high specific stiffness and specific strength. Their mechanical properties are strongly influenced by the carbon fiber content in the composites. Measurement of the carbon fiber content in CFRPs is essential for product quality control and process optimization. In this work, a novel carbonization-in-nitrogen method (CIN) is developed to characterize the fiber content in carbon fiber reinforced thermoset and thermoplastic composites. In this method, a carbon fiber composite sample is carbonized in a nitrogen environment at elevated temperatures, alongside a neat resin sample. The carbon fibers are protected from oxidization while the resin (the neat resin and the resin matrix in the composite sample) is carbonized under the nitrogen environment. The residue of the carbonized neat resin sample is used to calibrate the resin carbonization rate and calculate the amount of the resin matrix in the composite sample. The new method has been validated on several thermoset and thermoplastic resin systems and found to yield an accurate measurement of fiber content in carbon fiber polymer composites. In order to further understand the thermal degradation behavior of the high temperature thermoplastic polymer during the carbonization process, the mechanism and the kinetic model of thermal degradation behavior of carbon fiber reinforced poly (phenylene sulfide) (CPPS) are studied using thermogravimetry analysis (TGA). The CPPS is subjected to TGA in an air and nitrogen atmosphere at heating rates from 5 to 40°C min--1. The TGA curves obtained in air are different from those in nitrogen. This demonstrates that weight loss occurs in a single stage in nitrogen but in two stages in air. To elucidate this difference, thermal decomposition kinetics is analyzed by applying the Kissinger, Flynn-Wall-Ozawa, Coat-Redfern and

  4. Carbon dioxide emissions from fossil-fuel use, 1751-1950

    Energy Technology Data Exchange (ETDEWEB)

    Andres, R.J.; Fielding, D.J. [Alaska Fairbanks Univ., Fairbanks AK (United States). Inst. of Northern Engineering; Marland, G.; Boden, T.A. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Kumar, N.; Kearney, A.T. [153 East 53rd Street, New York, NY (United States)

    1999-09-01

    Newly compiled energy statistics allow for an estimation of the complete time series of carbon dioxide (CO{sub 2}) emissions from fossil-fuel use for the years 1751 to the present. The time series begins with 3 x 10{sup 6} metric tonnes carbon (C). This initial flux represents the early stages of the fossil-fuel era. The CO{sub 2} flux increased exponentially until World War I. The time series derived here seamlessly joins the modern 1950 to present time series. Total cumulative CO{sub 2} emissions through 1949 were 61.0 x 10{sup 9} tonnes C from fossil-fuel use, virtually all since the beginning of the Industrial Revolution around 1860. The rate of growth continues to grow during present times, generating debate on the probability of enhanced greenhouse warming. In addition to global totals, national totals and 1 deg global distributions of the data have been calculated 18 refs, 4 figs, 2 tabs

  5. Methodology for calculation of carbon emission and energy generation efficiency by fossil coal thermal power plants

    International Nuclear Information System (INIS)

    Licks, Leticia A.; Pires, Marcal

    2008-01-01

    This work intends to evaluate the emissions of carbon dioxide (CO 2 ) emitted by the burning of fossil coal in Brazil. So, a detailed methodology is proposed for calculation of CO 2 emissions from the carbon emission coefficients specific for the Brazilian carbons. Also, the using of secondary fuels (fuel oil and diesel oil) were considered and the power generation for the calculation of emissions and efficiencies of each power plant as well. The obtained results indicate carbon emissions for the year 2002 approximately of the order of 1,794 Gg, with 20% less than the obtained by the official methodology (MCT). Such differences are related to the non consideration of the humidity containment of the coals as well as the using of generic coefficients not adapted to the Brazilian coals. The obtained results indicate the necessity to review the emission inventories and the modernization of the burning systems aiming the increase the efficiency and reduction of the CO 2 and other pollutants, as an alternative for maintaining the sustainable form of using the fossil coal in the country

  6. Wildfire Activity Across the Triassic-Jurassic Boundary in the Polish Basin: Evidence from New Fossil Charcoal & Carbon-isotope Data

    Science.gov (United States)

    Pointer, R.; Belcher, C.; Hesselbo, S. P.; Hodbod, M.; Pieńkowski, G.

    2017-12-01

    New fossil charcoal abundance and carbon-isotope data from two sedimentary cores provide new evidence of extreme environmental conditions in the Polish Basin during the Latest Triassic to Earliest Jurassic. Sedimentary cores from the Polish Basin provide an excellent record of terrestrial environmental conditions across the Triassic-Jurassic Boundary, a time of climatic extremes. Previous work has shown that the marine realm was affected by a large perturbation to the carbon cycle across the Triassic-Jurassic Boundary (manifested by large negative and positive carbon-isotope excursions) and limited records of charcoal abundance and organic geochemistry have indicated important changes in fire regime in the coeval ecosystems. Here we present two new carbon-isotope records generated from fossil plant matter across the Triassic-Jurassic boundary, and present new charcoal records. The charcoal abundance data confirm that there was variation in wildfire activity during the Late Triassic-Early Jurassic in the Polish Basin. Peaks in the number of fossil charcoal fragments present occur in both sedimentary cores, and increases in fossil charcoal abundance are linked to wildfires, signalling a short-lived rise in wildfire activity. Fossil charcoal abundance does not appear to be fully controlled by total organic matter content, depositional environment or bioturbation. We argue that increased wildfire activity is likely caused by an increase in ignition of plant material as a result of an elevated number of lightning strikes. Global warming (caused by a massive input of carbon into the atmosphere, as indicated by carbon-isotope data) can increase storm activity, leading to increased numbers of lightning strikes. Previous Triassic-Jurassic Boundary wildfire studies have found fossil charcoal abundance peaks at other northern hemisphere sites (Denmark & Greenland), and concluded that they represent increases in wildfire activity in the earliest Jurassic. Our new charcoal and

  7. Climate Change Effects of Forest Management and Substitution of Carbon-Intensive Materials and Fossil Fuels

    Science.gov (United States)

    Sathre, R.; Gustavsson, L.; Haus, S.; Lundblad, M.; Lundström, A.; Ortiz, C.; Truong, N.; Wikberg, P. E.

    2016-12-01

    Forests can play several roles in climate change mitigation strategies, for example as a reservoir for storing carbon and as a source of renewable materials and energy. To better understand the linkages and possible trade-offs between different forest management strategies, we conduct an integrated analysis where both sequestration of carbon in growing forests and the effects of substituting carbon intensive products within society are considered. We estimate the climate effects of directing forest management in Sweden towards increased carbon storage in forests, with more land set-aside for protection, or towards increased forest production for the substitution of carbon-intensive materials and fossil fuels, relative to a reference case of current forest management. We develop various scenarios of forest management and biomass use to estimate the carbon balances of the forest systems, including ecological and technological components, and their impacts on the climate in terms of cumulative radiative forcing over a 100-year period. For the reference case of current forest management, increasing the harvest of forest residues is found to give increased climate benefits. A scenario with increased set-aside area and the current level of forest residue harvest begins with climate benefits compared to the reference scenario, but the benefits cannot be sustained for 100 years because the rate of carbon storage in set-aside forests diminishes over time as the forests mature, but the demand for products and fuels remains. The most climatically beneficial scenario, expressed as reduced cumulative radiative forcing, in both the short and long terms is a strategy aimed at high forest production, high residue recovery rate, and high efficiency utilization of harvested biomass. Active forest management with high harvest level and efficient forest product utilization will provide more climate benefit, compared to reducing harvest and storing more carbon in the forest. Figure

  8. Household consumption, associated fossil fuel demand and carbon dioxide emissions: The case of Greece between 1990 and 2006

    International Nuclear Information System (INIS)

    Papathanasopoulou, Eleni

    2010-01-01

    This paper explores how Greece's household consumption has changed between 1990 and 2006 and its environmental implications in terms of fossil fuel demand and carbon dioxide (CO 2 ) emissions. The results show that the 44% increase in Greece's household expenditure between 1990 and 2006 was accompanied by a 67% increase in fossil fuel demand. Of this total, indirect demand accounted for approximately 60% throughout the 16-year period, increasing by 56% overall, whereas direct fossil fuel demand grew by 80%. The results also show that associated CO 2 emissions increased by 60%, resulting in a 'relative decoupling' from energy demand. This relative decoupling is shown to be due to fossil fuel mix changes from the supply side rather than action from consumers. These insights highlight the opportunities for demand-side policies to further reduce fossil fuel demand and CO 2 emissions, allowing Greece to set more proactive and ambitious post-Kyoto targets.

  9. The effect of size-control policy on unified energy and carbon efficiency for Chinese fossil fuel power plants

    International Nuclear Information System (INIS)

    Zhang, Ning; Kong, Fanbin; Choi, Yongrok; Zhou, P.

    2014-01-01

    This paper examines the effect of size control policy on the energy and carbon efficiency for Chinese fossil fuel power industry. For this purpose, we propose two non-radial directional distance functions for energy/carbon efficiency analysis of fossil fuel electricity generation. One is named a total-factor directional distance function that incorporates the inefficiency of all input and output factors to measure the unified (operational and environmental) efficiency of fossil fuel power plants, and the other is called an energy–environmental directional distance function that can be used to measure the energy–environmental performance of fossil fuel electric power plants. Several standardized indicators for measuring unified efficiency and energy–environmental performance are derived from the two directional distance functions. An empirical study of 252 fossil fuel power plants in China is conducted by using the proposed approach. Our empirical results show that there exists a significant positive relationship between the plant size and unified efficiency, the five state-owned companies show lower unified efficiency and energy–environmental performance than other companies. It is suggested that Chinese government might need to consider private incentives and deregulation for its state-owned enterprises to improve their performance proactively. - Highlights: • Two non-radial directional distance functions are presented for energy/carbon efficiency analysis. • An empirical study of 252 fossil fuel power plants in China is conducted. • The five state-owned companies show lower unified efficiency and energy–environmental performance

  10. Energy properties of solid fossil fuels and solid biofuels

    International Nuclear Information System (INIS)

    Holubcik, Michal; Jandacka, Jozef; Kolkova, Zuzana

    2016-01-01

    The paper deals about the problematic of energy properties of solid biofuels in comparison with solid fossil fuels. Biofuels are alternative to fossil fuels and their properties are very similar. During the experiments were done in detail experiments to obtain various properties of spruce wood pellets and wheat straw pellets like biofuels in comparison with brown coal and black coal like fossil fuels. There were tested moisture content, volatile content, fixed carbon content, ash content, elementary analysis (C, H, N, S content) and ash fusion temperatures. The results show that biofuels have some advantages and also disadvantages in comparison with solid fossil fuels.

  11. Energy properties of solid fossil fuels and solid biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Holubcik, Michal, E-mail: michal.holubcik@fstroj.uniza.sk; Jandacka, Jozef, E-mail: jozef.jandacka@fstroj.uniza.sk [University of Žilina, Faculty of Mechanical Engineering, Department of Power Engineering, Univerzitná 8215/1, 010 26 Žilina (Slovakia); Kolkova, Zuzana, E-mail: zuzana.kolkova@rc.uniza.sk [Research centre, University of Žilina, Univerzitna 8215/1, 010 26 Žilina (Slovakia)

    2016-06-30

    The paper deals about the problematic of energy properties of solid biofuels in comparison with solid fossil fuels. Biofuels are alternative to fossil fuels and their properties are very similar. During the experiments were done in detail experiments to obtain various properties of spruce wood pellets and wheat straw pellets like biofuels in comparison with brown coal and black coal like fossil fuels. There were tested moisture content, volatile content, fixed carbon content, ash content, elementary analysis (C, H, N, S content) and ash fusion temperatures. The results show that biofuels have some advantages and also disadvantages in comparison with solid fossil fuels.

  12. Ambient measurements and source apportionment of fossil fuel and biomass burning black carbon in Ontario

    Science.gov (United States)

    Healy, R. M.; Sofowote, U.; Su, Y.; Debosz, J.; Noble, M.; Jeong, C.-H.; Wang, J. M.; Hilker, N.; Evans, G. J.; Doerksen, G.; Jones, K.; Munoz, A.

    2017-07-01

    Black carbon (BC) is of significant interest from a human exposure perspective but also due to its impacts as a short-lived climate pollutant. In this study, sources of BC influencing air quality in Ontario, Canada were investigated using nine concurrent Aethalometer datasets collected between June 2015 and May 2016. The sampling sites represent a mix of background and near-road locations. An optical model was used to estimate the relative contributions of fossil fuel combustion and biomass burning to ambient concentrations of BC at every site. The highest annual mean BC concentration was observed at a Toronto highway site, where vehicular traffic was found to be the dominant source. Fossil fuel combustion was the dominant contributor to ambient BC at all sites in every season, while the highest seasonal biomass burning mass contribution (35%) was observed in the winter at a background site with minimal traffic contributions. The mass absorption cross-section of BC was also investigated at two sites, where concurrent thermal/optical elemental carbon data were available, and was found to be similar at both locations. These results are expected to be useful for comparing the optical properties of BC at other near-road environments globally. A strong seasonal dependence was observed for fossil fuel BC at every Ontario site, with mean summer mass concentrations higher than their respective mean winter mass concentrations by up to a factor of two. An increased influence from transboundary fossil fuel BC emissions originating in Michigan, Ohio, Pennsylvania and New York was identified for the summer months. The findings reported here indicate that BC should not be considered as an exclusively local pollutant in future air quality policy decisions. The highest seasonal difference was observed at the highway site, however, suggesting that changes in fuel composition may also play an important role in the seasonality of BC mass concentrations in the near-road environment

  13. Contenu énergétique des alcools d'origine fossile ou biomasse Energy Content of Alcohols of Fossil Or Biomass Origin

    Directory of Open Access Journals (Sweden)

    Arlie J. P.

    2006-11-01

    Full Text Available En utilisant une méthode basée sur le contenu énergétique, défini comme étant la quantité d'énergie mise en oeuvre dans le processus de fabrication depuis la matière première jsuqu'au produit considéré, on compare les filières de production basées sur des matières premières soit d'origine fossile, soit d'origine biomasse. Ces filières peuvent être utilisées pour produire les divers alcools que sont le méthanol, l'éthanol et le butanol. II est montré, qu'en l'état actuel des technologies de fabrication, la comparaison énergétique est très en faveur de la filière matière première renouvelable qui fait apparaître un gain énergétique qui varie suivant les cas étudiés entre 0,1 et 1,5 tep par tonne de produit. Production routes based on raw materials from either fossil or biomass origin are compared using a method based on the energy content, which is defined as being the amount of energy implemented in the manufacturing process starting with the raw material and going to the product being considered. These routes can be used to produce different alcohols such as methanol, ethanol and butanol. Given the current state of manufacturing technologies, this article shows that an energy comparison is highly in favor of the renewable raw-material route which shows an energy gain that varies, according to the cases examined, between 0. 1 and 1. 5 tOE per ton of product.

  14. An overview of alternative fossil fuel price and carbon regulation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ryan; Bolinger, Mark

    2004-10-01

    The benefits of the Department of Energy's research and development (R&D) efforts have historically been estimated under business-as-usual market and policy conditions. In recognition of the insurance value of R&D, however, the Office of Energy Efficiency and Renewable Energy (EERE) and the Office of Fossil Energy (FE) have been exploring options for evaluating the benefits of their R&D programs under an array of alternative futures. More specifically, an FE-EERE Scenarios Working Group (the Working Group) has proposed to EERE and FE staff the application of an initial set of three scenarios for use in the Working Group's upcoming analyses: (1) a Reference Case Scenario, (2) a High Fuel Price Scenario, which includes heightened natural gas and oil prices, and (3) a Carbon Cap-and-Trade Scenario. The immediate goal is to use these scenarios to conduct a pilot analysis of the benefits of EERE and FE R&D efforts. In this report, the two alternative scenarios being considered by EERE and FE staff--carbon cap-and-trade and high fuel prices--are compared to other scenarios used by energy analysts and utility planners. The report also briefly evaluates the past accuracy of fossil fuel price forecasts. We find that the natural gas prices through 2025 proposed in the FE-EERE Scenarios Working Group's High Fuel Price Scenario appear to be reasonable based on current natural gas prices and other externally generated gas price forecasts and scenarios. If anything, an even more extreme gas price scenario might be considered. The price escalation from 2025 to 2050 within the proposed High Fuel Price Scenario is harder to evaluate, primarily because few existing forecasts or scenarios extend beyond 2025, but, at first blush, it also appears reasonable. Similarly, we find that the oil prices originally proposed by the Working Group in the High Fuel Price Scenario appear to be reasonable, if not conservative, based on: (1) the current forward market for oil, (2

  15. Mechanistic modelling of Middle Eocene atmospheric carbon dioxide using fossil plant material

    Science.gov (United States)

    Grein, Michaela; Roth-Nebelsick, Anita; Wilde, Volker; Konrad, Wilfried; Utescher, Torsten

    2010-05-01

    Various proxies (such as pedogenic carbonates, boron isotopes or phytoplankton) and geochemical models were applied in order to reconstruct palaeoatmospheric carbon dioxide, partially providing conflicting results. Another promising proxy is the frequency of stomata (pores on the leaf surface used for gaseous exchange). In this project, fossil plant material from the Messel Pit (Hesse, Germany) is used to reconstruct atmospheric carbon dioxide concentration in the Middle Eocene by analyzing stomatal density. We applied the novel mechanistic-theoretical approach of Konrad et al. (2008) which provides a quantitative derivation of the stomatal density response (number of stomata per leaf area) to varying atmospheric carbon dioxide concentration. The model couples 1) C3-photosynthesis, 2) the process of diffusion and 3) an optimisation principle providing maximum photosynthesis (via carbon dioxide uptake) and minimum water loss (via stomatal transpiration). These three sub-models also include data of the palaeoenvironment (temperature, water availability, wind velocity, atmospheric humidity, precipitation) and anatomy of leaf and stoma (depth, length and width of stomatal porus, thickness of assimilation tissue, leaf length). In order to calculate curves of stomatal density as a function of atmospheric carbon dioxide concentration, various biochemical parameters have to be borrowed from extant representatives. The necessary palaeoclimate data are reconstructed from the whole Messel flora using Leaf Margin Analysis (LMA) and the Coexistence Approach (CA). In order to obtain a significant result, we selected three species from which a large number of well-preserved leaves is available (at least 20 leaves per species). Palaeoclimate calculations for the Middle Eocene Messel Pit indicate a warm and humid climate with mean annual temperature of approximately 22°C, up to 2540 mm mean annual precipitation and the absence of extended periods of drought. Mean relative air

  16. Gridded uncertainty in fossil fuel carbon dioxide emission maps, a CDIAC example

    Directory of Open Access Journals (Sweden)

    R. J. Andres

    2016-12-01

    Full Text Available Due to a current lack of physical measurements at appropriate spatial and temporal scales, all current global maps and distributions of fossil fuel carbon dioxide (FFCO2 emissions use one or more proxies to distribute those emissions. These proxies and distribution schemes introduce additional uncertainty into these maps. This paper examines the uncertainty associated with the magnitude of gridded FFCO2 emissions. This uncertainty is gridded at the same spatial and temporal scales as the mass magnitude maps. This gridded uncertainty includes uncertainty contributions from the spatial, temporal, proxy, and magnitude components used to create the magnitude map of FFCO2 emissions. Throughout this process, when assumptions had to be made or expert judgment employed, the general tendency in most cases was toward overestimating or increasing the magnitude of uncertainty. The results of the uncertainty analysis reveal a range of 4–190 %, with an average of 120 % (2σ for populated and FFCO2-emitting grid spaces over annual timescales. This paper also describes a methodological change specific to the creation of the Carbon Dioxide Information Analysis Center (CDIAC FFCO2 emission maps: the change from a temporally fixed population proxy to a temporally varying population proxy.

  17. Gridded uncertainty in fossil fuel carbon dioxide emission maps, a CDIAC example

    Science.gov (United States)

    Andres, Robert J.; Boden, Thomas A.; Higdon, David M.

    2016-12-01

    Due to a current lack of physical measurements at appropriate spatial and temporal scales, all current global maps and distributions of fossil fuel carbon dioxide (FFCO2) emissions use one or more proxies to distribute those emissions. These proxies and distribution schemes introduce additional uncertainty into these maps. This paper examines the uncertainty associated with the magnitude of gridded FFCO2 emissions. This uncertainty is gridded at the same spatial and temporal scales as the mass magnitude maps. This gridded uncertainty includes uncertainty contributions from the spatial, temporal, proxy, and magnitude components used to create the magnitude map of FFCO2 emissions. Throughout this process, when assumptions had to be made or expert judgment employed, the general tendency in most cases was toward overestimating or increasing the magnitude of uncertainty. The results of the uncertainty analysis reveal a range of 4-190 %, with an average of 120 % (2σ) for populated and FFCO2-emitting grid spaces over annual timescales. This paper also describes a methodological change specific to the creation of the Carbon Dioxide Information Analysis Center (CDIAC) FFCO2 emission maps: the change from a temporally fixed population proxy to a temporally varying population proxy.

  18. Stable carbon isotope ratios and intrinsic water-use efficiency of Miocene fossil leaves compared to modern congeners

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, J.D.; Zhang, J.; Rember, W.C.; Jennings, D.; Larson, P. (Univ. of Idaho, Moscow, ID (United States))

    1994-06-01

    Miocene fossil leaves of forest trees were extracted from the Clarkia, Idaho fossil beds and their stable carbon isotope ratios were analyzed. Fossils had higher lignin concentrations and lower cellulose concentrations that modern leaves due to diagenesis and the HF used to extract the fossils. Therefore, [delta][sup 13]C of extracted fossil lignin was compared to that of modern lignin. Fossil lignin [delta][sup 13]C was significantly different from that of congeneric modern leaves (paired t-test, P<0.0001), but was 1.9% less negative. Gymnosperms (Metasequoia, Taxodium) were less negative than angiosperms (e.g., Magnolia, Quercus, Acer, Persea), but no difference between evergreen and deciduous species was detected. Using published estimates of the concentration and [delta][sup 13]C of atmospheric CO[sub 2] during the Miocene was estimated the CO[sub 2] partial pressure gradient across the stomata (intrinsic water-use efficiency). Intrinsic water-use efficiency was at least 70% higher during this past [open quotes]greenhouse[close quotes] period than at present.

  19. The Fossile Episode

    OpenAIRE

    Hassler, John; Sinn, Hans-Werner

    2012-01-01

    We build a two-sector dynamic general equilibrium model with one-sided substitutability between fossil carbon and biocarbon. One shock only, the discovery of the technology to use fossil fuels, leads to a transition from an inital pre-industrial phase to three following phases: a pure fossil carbon phase, a mixed fossil and biocarbon phase and an absorbing biocarbon phase. The increased competition for biocarbon during phase 3 and 4 leads to increasing food prices. We provide closed form expr...

  20. The Fossil Episode

    OpenAIRE

    John Hassler; Hans-Werner Sinn

    2012-01-01

    We build a two-sector dynamic general equilibrium model with one-sided substitutability between fossil carbon and biocarbon. One shock only, the discovery of the technology to use fossil fuels, leads to a transition from an initial pre-industrial phase to three following phases: a pure fossil carbon phase, a mixed fossil and biocarbon phase and an absorbing biocarbon phase. The increased competition for biocarbon during phase 3 and 4 leads to increasing food prices. We provide closed form exp...

  1. Gridded Uncertainty Maps of Fossil Fuel Carbon Dioxide Emissions: A New Data Product

    Science.gov (United States)

    Andres, R. J.; Boden, T.

    2014-12-01

    With the publication of a new assessment of the uncertainty associated with the mass of fossil fuel carbon dioxide (FFCO2) emissions (2014, Tellus B, 66, 23616, doi:10.3402/tellusb.v66.23616), it is now possible to extend that work with a gridded map of fossil fuel emission uncertainties. The new data product was created to be paired with the long-used, Carbon Dioxide Information Analysis Center (CDIAC), emission year 1751-present, one degree latitude by one degree longitude (1x1) mass of emissions data product (http://cdiac.ornl.gov/epubs/ndp/ndp058/ndp058_v2013.html). Now, for the first time, data users will have FFCO2 emission information that represents both mass and uncertainty, each of which varies in both time and space. The new data product was constructed by examining the individual uncertainties in each of the input data sets to the gridded mass maps and then combining these individual uncertainties into an overall uncertainty for the mass maps. The input data sets include a table of the mass of FFCO2 emissions by country and year, the one degree geographic map of emissions which includes changing borders on an annual time scale and ties the mass of emissions to location, and the one degree population proxy used to distribute the mass of emissions within each country. As the three input data sets are independent of each other, their combination for the overall uncertainty is accomplished by a simple square root of the sum of the squares procedure. The resulting uncertainty data product is gridded at 1x1 and exactly overlays the 1x1 mass emission maps. The default temporal resolution is annual, but a companion product is also available at monthly time scales. The monthly uncertainty product uses the same input data sets, but the mass uncertainty is scaled as described in the monthly mass product description paper (2011, Tellus B, 63:309-327, doi: 10.1111/j.1600-0889.2011.00530.x). The gridded uncertainty maps cover emission year 1950 to 2010. The start

  2. Influence of carbon dioxide content in the biogas to nitrogen oxides emissions

    Directory of Open Access Journals (Sweden)

    Živković Marija A.

    2010-01-01

    Full Text Available Fuels derived from biomass are an alternative solution for the fossil fuel shortage. Usually this kind of fuels is called low calorific value fuels, due to the large proportion of inert components in their composition. The most common is carbon dioxide, and its proportion in biogas can be different, from 10 up to 40%, or even more. The presence of inert component in the composition of biogas causes the problems that are related with flame blow off limits. One of the possibilities for efficient combustion of biogas is the combustion in swirling flow including a pilot burner, aimed to expand the borders of stable combustion. This paper presents an analysis of the influence of the carbon dioxide content to the nitrogen oxides emissions. Laboratory biogas was used with different content of CO2 (10, 20, 30 and 40%. Investigation was carried out for different nominal powers, coefficients of excess air and carbon dioxide content. With increasing content of carbon dioxide, emission of nitrogen oxides was reduced, and this trend was the same throughout the whole range of excess air, carried out through measurements. Still, the influence of carbon dioxide content is significantly less than the influence of excess air. The coefficient of excess air greatly affects the production of radicals which are essential for the formation of nitrogen oxides, O, OH and CH. Also, the results show that the nominal power has no impact on the emission of nitrogen oxides.

  3. Large contribution of fossil fuel derived secondary organic carbon to water soluble organic aerosols in winter haze in China

    Directory of Open Access Journals (Sweden)

    Y.-L. Zhang

    2018-03-01

    Full Text Available Water-soluble organic carbon (WSOC is a large fraction of organic aerosols (OA globally and has significant impacts on climate and human health. The sources of WSOC remain very uncertain in polluted regions. Here we present a quantitative source apportionment of WSOC, isolated from aerosols in China using radiocarbon (14C and offline high-resolution time-of-flight aerosol mass spectrometer measurements. Fossil emissions on average accounted for 32–47 % of WSOC. Secondary organic carbon (SOC dominated both the non-fossil and fossil derived WSOC, highlighting the importance of secondary formation to WSOC in severe winter haze episodes. Contributions from fossil emissions to SOC were 61 ± 4 and 50 ± 9 % in Shanghai and Beijing, respectively, significantly larger than those in Guangzhou (36 ± 9 % and Xi'an (26 ± 9 %. The most important primary sources were biomass burning emissions, contributing 17–26 % of WSOC. The remaining primary sources such as coal combustion, cooking and traffic were generally very small but not negligible contributors, as coal combustion contribution could exceed 10 %. Taken together with earlier 14C source apportionment studies in urban, rural, semi-urban and background regions in Asia, Europe and the USA, we demonstrated a dominant contribution of non-fossil emissions (i.e., 75 ± 11 % to WSOC aerosols in the Northern Hemisphere; however, the fossil fraction is substantially larger in aerosols from East Asia and the eastern Asian pollution outflow, especially during winter, due to increasing coal combustion. Inclusion of our findings can improve a modelling of effects of WSOC aerosols on climate, atmospheric chemistry and public health.

  4. Large contribution of fossil fuel derived secondary organic carbon to water soluble organic aerosols in winter haze in China

    Science.gov (United States)

    Zhang, Yan-Lin; El-Haddad, Imad; Huang, Ru-Jin; Ho, Kin-Fai; Cao, Jun-Ji; Han, Yongming; Zotter, Peter; Bozzetti, Carlo; Daellenbach, Kaspar R.; Slowik, Jay G.; Salazar, Gary; Prévôt, André S. H.; Szidat, Sönke

    2018-03-01

    Water-soluble organic carbon (WSOC) is a large fraction of organic aerosols (OA) globally and has significant impacts on climate and human health. The sources of WSOC remain very uncertain in polluted regions. Here we present a quantitative source apportionment of WSOC, isolated from aerosols in China using radiocarbon (14C) and offline high-resolution time-of-flight aerosol mass spectrometer measurements. Fossil emissions on average accounted for 32-47 % of WSOC. Secondary organic carbon (SOC) dominated both the non-fossil and fossil derived WSOC, highlighting the importance of secondary formation to WSOC in severe winter haze episodes. Contributions from fossil emissions to SOC were 61 ± 4 and 50 ± 9 % in Shanghai and Beijing, respectively, significantly larger than those in Guangzhou (36 ± 9 %) and Xi'an (26 ± 9 %). The most important primary sources were biomass burning emissions, contributing 17-26 % of WSOC. The remaining primary sources such as coal combustion, cooking and traffic were generally very small but not negligible contributors, as coal combustion contribution could exceed 10 %. Taken together with earlier 14C source apportionment studies in urban, rural, semi-urban and background regions in Asia, Europe and the USA, we demonstrated a dominant contribution of non-fossil emissions (i.e., 75 ± 11 %) to WSOC aerosols in the Northern Hemisphere; however, the fossil fraction is substantially larger in aerosols from East Asia and the eastern Asian pollution outflow, especially during winter, due to increasing coal combustion. Inclusion of our findings can improve a modelling of effects of WSOC aerosols on climate, atmospheric chemistry and public health.

  5. Life cycle GHG assessment of fossil fuel power plants with carbon capture and storage

    International Nuclear Information System (INIS)

    Odeh, Naser A.; Cockerill, Timothy T.

    2008-01-01

    The evaluation of life cycle greenhouse gas emissions from power generation with carbon capture and storage (CCS) is a critical factor in energy and policy analysis. The current paper examines life cycle emissions from three types of fossil-fuel-based power plants, namely supercritical pulverized coal (super-PC), natural gas combined cycle (NGCC) and integrated gasification combined cycle (IGCC), with and without CCS. Results show that, for a 90% CO 2 capture efficiency, life cycle GHG emissions are reduced by 75-84% depending on what technology is used. With GHG emissions less than 170 g/kWh, IGCC technology is found to be favorable to NGCC with CCS. Sensitivity analysis reveals that, for coal power plants, varying the CO 2 capture efficiency and the coal transport distance has a more pronounced effect on life cycle GHG emissions than changing the length of CO 2 transport pipeline. Finally, it is concluded from the current study that while the global warming potential is reduced when MEA-based CO 2 capture is employed, the increase in other air pollutants such as NO x and NH 3 leads to higher eutrophication and acidification potentials

  6. Groundwater Dynamics in Fossil Fractured Carbonate Aquifers in Eastern Arabian Peninsula

    Science.gov (United States)

    Farag, A. Z. A.; Heggy, E.; Helal, M.; Thirunavukkarasu, D.; Scabbia, G.; Palmer, E. M.

    2017-12-01

    The Eastern Arabian Peninsula, notably the Qatar Peninsula, represents one of the highest natural groundwater discharge areas for the Arabian platform fossil aquifer system. Groundwater flow dynamics in these aquifers trace the paleoclimatic conditions that have prevailed the Arabian Peninsula during the Quaternary. In such settings, connections between aquifers strongly affect the flow dynamics, water quality and availability as well as karst formation and landscape evolution. Geological structures such as folds, faults and fractures are central to aquifer connectivity, yet their role on groundwater flow is poorly understood. Herein, we performed a detailed mapping of exposed and buried structural features in Qatar using Landsat, Sentinel and ALOS-PalSAR scenes, correlated with field and laboratory measurements to understand their role in aquifer connectivity and groundwater dynamics. Our results suggest that E-W oriented fold-related faults act as vertical conduits along which artesian upward leakages from the deep aquifers (e.g. Aruma and Umm er Radhuma) take place into the shallower aquifers (e.g. Rus and Dammam). Evidence includes: (1) the high potentiometric surfaces of deep aquifers (6 to 25 m amsl) compare to the shallower aquifers (2-3 m amsl for the same region); (2) anomalous elevation of groundwater levels and steeper hydraulic gradients in densely faulted regions; (3) mixed isotopic composition in shallow aquifers (δ18O: -5 to -2 ‰, δ2H: -40 to -10 ‰) between reported deep fossil waters (δ18O: -6.3 ‰, δ2H: -55 ‰) and modern meteoric waters (weighted average: δ18O: -0.6 ‰, δ2H: 4 ‰); (4) abundant meso-crystalline fibrous gypsum veins along fault zones in the Dammam Formation (up to 28 m amsl) in southern Qatar where the anhydritic member of the Rus Formation predominates the subsurface leading to gypsum oversaturation of groundwater. The similarity of crystal morphology (platy crystals under SEM), mineralogical compositions from XRD

  7. Carbon Capture and Water Emissions Treatment System (CCWESTRS) at Fossil-Fueled Electric Generating Plants

    Energy Technology Data Exchange (ETDEWEB)

    P. Alan Mays; Bert R. Bock; Gregory A. Brodie; L. Suzanne Fisher; J. Devereux Joslin; Donald L. Kachelman; Jimmy J. Maddox; N. S. Nicholas; Larry E. Shelton; Nick Taylor; Mark H. Wolfe; Dennis H. Yankee; John Goodrich-Mahoney

    2005-08-30

    The Tennessee Valley Authority (TVA), the Electric Power Research Institute (EPRI), and the Department of Energy-National Energy Technologies Laboratory (DOE-NETL) are evaluating and demonstrating integration of terrestrial carbon sequestration techniques at a coal-fired electric power plant through the use of Flue Gas Desulfurization (FGD) system gypsum as a soil amendment and mulch, and coal fly ash pond process water for periodic irrigation. From January to March 2002, the Project Team initiated the construction of a 40 ha Carbon Capture and Water Emissions Treatment System (CCWESTRS) near TVA's Paradise Fossil Plant on marginally reclaimed surface coal mine lands in Kentucky. The CCWESTRS is growing commercial grade trees and cover crops and is expected to sequester 1.5-2.0 MT/ha carbon per year over a 20-year period. The concept could be used to meet a portion of the timber industry's needs while simultaneously sequestering carbon in lands which would otherwise remain non-productive. The CCWESTRS includes a constructed wetland to enhance the ability to sequester carbon and to remove any nutrients and metals present in the coal fly ash process water runoff. The CCWESTRS project is a cooperative effort between TVA, EPRI, and DOE-NETL, with a total budget of $1,574,000. The proposed demonstration project began in October 2000 and has continued through December 2005. Additional funding is being sought in order to extend the project. The primary goal of the project is to determine if integrating power plant processes with carbon sequestration techniques will enhance carbon sequestration cost-effectively. This goal is consistent with DOE objectives to provide economically competitive and environmentally safe options to offset projected growth in U.S. baseline emissions of greenhouse gases after 2010, achieve the long-term goal of $10/ton of avoided net costs for carbon sequestration, and provide half of the required reductions in global greenhouse gases by

  8. A New Data Product: Gridded Uncertainty Maps of Fossil Fuel Carbon Dioxide Emissions

    Science.gov (United States)

    Andres, R. J.; Boden, T.

    2015-12-01

    Gridded uncertainty maps of fossil fuel carbon dioxide (FFCO2) emissions are a new data product that is currently in the process of being completed and published. This work is based on the relatively new assessment of the uncertainty associated with the mass of FFCO2 emissions (2014, Tellus B, 66, 23616, doi:10.3402/tellusb.v66.23616). The new data product was created to be paired with the long-used, Carbon Dioxide Information Analysis Center (CDIAC), emission year 1751-present, one degree latitude by one degree longitude (1x1) mass of emissions data product (http://cdiac.ornl.gov/epubs/ndp/ndp058/ndp058_v2013.html). Now, data users will have FFCO2 emission information that represents both mass and uncertainty, each of which varies in both time and space. The new data product was constructed by examining the individual uncertainties in each of the input data sets to the gridded mass maps and then combining these individual uncertainties into an overall uncertainty for the mass maps. The input data sets include a table of the mass of FFCO2 emissions by country and year, the one degree geographic map of emissions which includes changing borders on an annual time scale and ties the mass of emissions to location, and the one degree population proxy used to distribute the mass of emissions within each country. As the three input data sets are independent of each other, their combination for the overall uncertainty is accomplished by a simple square root of the sum of the squares procedure. The resulting uncertainty data product is gridded at 1x1 and exactly overlays the 1x1 mass emission maps. The default temporal resolution is annual, but a companion product is also available at monthly time scales. The monthly uncertainty product uses the same input data sets, but the mass uncertainty is scaled as described in the monthly mass product description paper (2011, Tellus B, 63:309-327, doi: 10.1111/j.1600-0889.2011.00530.x). The gridded uncertainty maps cover emission year

  9. Elucidating the consumption and CO_2 emissions of fossil fuels and low-carbon energy in the United States using Lotka–Volterra models

    International Nuclear Information System (INIS)

    Tsai, Bi-Huei; Chang, Chih-Jen; Chang, Chun-Hsien

    2016-01-01

    By using the Lotka–Volterra model, this work examines for the first time the feasibility of using low-carbon energy to reduce fossil fuel consumption in the United States and, ultimately, to decrease CO_2 emissions. The research sample in this work consists of data on energy consumption and CO_2 emissions in the United States. Parameter estimation results reveal that although the consumption of low-carbon energy increases the consumption of fossil fuels, the latter does not affect the former. Low-carbon energy usage, including nuclear energy and solar photovoltaic power, increases fossil fuel consumption because the entire lifetime of a nuclear or solar energy facility, from the construction of electricity plants to decommissioning, consumes tremendous amounts of fossil fuels. This result verifies the infeasibility of low-carbon energy to replace fossil fuels under the current mining technology, electricity generation skills and governmental policy in the United States and explains why the United States refused to become a signatory of the Kyoto Protocol. Equilibrium analysis results indicate that the annual consumption of fossil fuels will ultimately exceed that of low-carbon energy by 461%. Since our proposed Lotka–Volterra model accurately predicts the consumption and CO_2 emission of different energy sources, this work contributes to the energy policies. - Highlights: • Our Lotka–Volterra model accurately predicts consumption of different energy sources. • We find the current infeasibility of using low-carbon energy to reduce fossil fuels. • The set-up of nuclear and solar plants increases fossil fuel usage in the U.S. • The consumption of fossil fuels will exceed that of low-carbon energy by 435%. • United States government prefers economic development over environmental protection.

  10. ISLSCP II Carbon Dioxide Emissions from Fossil Fuels, Cement, and Gas Flaring

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains decadal (1950, 1960, 1970, 1980, 1990 and 1995) estimates of gridded fossil-fuel emissions, expressed in 1,000 metric tons C per...

  11. ISLSCP II Carbon Dioxide Emissions from Fossil Fuels, Cement, and Gas Flaring

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains decadal (1950, 1960, 1970, 1980, 1990 and 1995) estimates of gridded fossil-fuel emissions, expressed in 1,000 metric tons C per year per one...

  12. Do forests best mitigate CO2 emissions to the atmosphere by setting them aside for maximization of carbon storage or by management for fossil fuel substitution?

    DEFF Research Database (Denmark)

    Taeroe, Anders; Fayez Mustapha, Walid; Stupak, Inge

    2017-01-01

    fossil fuels and fossil fuel intensive materials. We defined a modelling framework for calculation of the carbon pools and fluxes along the forest energy and wood product supply chains over 200 years for three forest management alternatives (FMA): 1) a traditionally managed European beech forest...... the lowest CCE when using coal as the reference fossil fuel. With natural gas as the reference fossil fuel, the CCE of the business-as-usual and the energy poplar was nearly equal, with the unmanaged forest having the highest CCE after 40 years. CPTs ranged from 0 to 156 years, depending on the applied model...... assumptions. CCE and CPT were especially sensitive to the reference fossil fuel, material alternatives to wood, forest growth rates for the three FMAs, and energy conversion efficiencies. Assumptions about the long-term steady-state levels of carbon stored in the unmanaged forest had a limited effect on CCE...

  13. Quality and Distribution of Frozen Organic Matter (Old, Deep, Fossil Carbon) in Siberian Permafrost

    Science.gov (United States)

    Schirrmeister, Lutz; Strauss, Jens; Wetterich, Sebastian; Grosse, Guido; Overduin, Pier Paul

    2013-04-01

    Permafrost deposits constitute a large organic carbon (OC) pool vulnerable to degradation and potential carbon release due to global warming. Permafrost sections along coastal and river bank exposures and subsea cores in northeastern Siberia were studied for organic matter (OM) characteristics and ice content. OM stored in Quaternary permafrost grew, accumulated, froze, partly decomposed, and refroze under different periglacial environments, reflected in specific biogeochemical and cryolithological features. For the studied individual strata (Saalian ice-rich deposits, Pre-Eemian floodplain, Eemian lake deposits, Early to Middle Weichselian fluvial deposits, Middle Weichselian Yedoma, Late Weichselian Yedoma , Taberites, Holocene cover, Holocene thermokarst, Holocene thermoerosional valley and submerged lagoon and fluvial deposits) OM accumulation, preservation, and distribution are strongly linked to a broad variety of paleoenvironmental factors and specific surface and subsurface conditions before inclusion of OM into the permafrost. OM in permafrost includes twigs, leaves, peat, grass roots, plant detritus, and particulate and dissolved OM. The vertical distribution of total OC (TOC) in exposures varies from 0.1 wt % of the dry sediment in fluvial deposits to 45 wt % in Holocene peats. High TOC, high C/N, and low d13C reflect less decomposed OM accumulated under wet, anaerobic soil conditions characteristic of interglacial and interstadial periods. Glacial and stadial periods are characterized by less variable, low TOC, low C/N, and high d13C values indicating stable environments with reduced bioproductivity and stronger OM decomposition under dryer, aerobic soil conditions. Based on TOC data and updated information on bulk densities, we estimate average OC inventories for different stratigraphic units in northeastern Siberia, ranging from 7 kg C/m³ for Early Weichselian fluvial deposits, to 33 kg C/m³ for Middle Weichselian Yedoma deposits, to 75 kg C/m³ for

  14. Carbon emission and mitigation cost comparisons between fossil fuel, nuclear and renewable energy resources for electricity generation

    International Nuclear Information System (INIS)

    Sims, R.E.H.; Rogner, H.-H.; Gregory, Ken

    2003-01-01

    A study was conducted to compare the electricity generation costs of a number of current commercial technologies with technologies expected to become commercially available within the coming decade or so. The amount of greenhouse gas emissions resulting per kWh of electricity generated were evaluated. A range of fossil fuel alternatives (with and without physical carbon sequestration), were compared with the baseline case of a pulverised coal, steam cycle power plant. Nuclear, hydro, wind, bioenergy and solar generating plants were also evaluated. The objectives were to assess the comparative costs of mitigation per tonne of carbon emissions avoided, and to estimate the total amount of carbon mitigation that could result from the global electricity sector by 2010 and 2020 as a result of fuel switching, carbon dioxide sequestration and the greater uptake of renewable energy. Most technologies showed potential to reduce both generating costs and carbon emission avoidance by 2020 with the exception of solar power and carbon dioxide sequestration. The global electricity industry has potential to reduce its carbon emissions by over 15% by 2020 together with cost saving benefits compared with existing generation

  15. Direct quantification of PM2.5 fossil and biomass carbon within the Northern Front Range Air Quality Study's domain

    International Nuclear Information System (INIS)

    Klinedinst, D.B.; Currie, L.A.

    1999-01-01

    Radiocarbon ( 14 C) analyses of PM 2.5 (particulate matter with an aerodynamic diameter of 2.5 microm or less) of both ambient and source samples from the Northern Front Range Air Quality Study (NFRAQS) in Colorado were performed. The 14 C analyses were undertaken to provide direct fossil vs modern (biomass) carbon source discrimination data for a subset of summer and winter 1996--1997 samples collected within the Denver metropolitan area. Samples were prepared for 14 C accelerator mass spectrometry measurements using techniques specially developed for small samples, i.e., lt100 μg C. For the days and sampling periods analyzed the median and interquartile range of the winter blank corrected fraction of modern carbon was 23% (16--34%) at Welby and 27% (25--37%) at Brighton. The summer samples exhibited a more mixed signature with a median and interquartile range of 47% (9--70%). Source samples yielded 14 C signatures consistent with expectation. The authors conclude fossil-derived sources contribute substantially in both seasons and at both locations; however, the biomass carbon component dominates episodically in the summer

  16. Carbon and Oxygen Isotope Dendrochronology in Sub-Fossil Bog Oak Tree Rings - A Preliminary Study

    NARCIS (Netherlands)

    Sass, U.G.W.; Poole, I.; Wils, T.; Helle, G.; Schleser, G.H.; Bergen, van P.

    2005-01-01

    Isotope dendroclimatology is a relatively new field investigating environmental factors that control the radial growth of trees. Tree-ring series of sub-fossil bog oaks can be dated from sites across northwest Europe indicating that the environmental change(s) were regional rather than local. Bog

  17. Emissions of Water and Carbon Dioxide from Fossil-Fuel Combustion Contribute Directly to Ocean Mass and Volume Increases

    Science.gov (United States)

    Skuce, A. G.

    2014-12-01

    The direct, non-climate, contribution of carbon dioxide and water emissions from fossil-fuel (FF) combustion to the volume and mass of the oceans has been omitted from estimates of sea-level rise (SLR) in IPCC reports. Following the method of Gornitz et al. (1997), H2O emissions are estimated using carbon emissions from the Carbon Dioxide Information Analysis Center, along with typical carbon and hydrogen contents of FF. Historic H2O emissions from 1750 to 2010 amount to 430 ±50 PgH2O, equivalent to 1.2 ±0.2 mmSLR. Sometime in this decade the volume of H2O from historic FF combustion will exceed the volume of Lake Erie (480 km3). CO2 dissolved in the ocean increases the seawater volume by 31-33 mL mol-1 CO2. From 1750 to 2010, 370 ±70 PgCO2 from FF combustion has dissolved in the oceans, causing 0.7 ±0.2 mmSLR. Combined H2O+CO2emissions from FF have therefore added 1.9 ±0.4 mm to sea levels in the Industrial Era. Combustion of FF in 2010 resulted in emissions of 32 PgCO2 and 12 ±1 PgH2O. SLR contributions for that year from FF emissions were 0.033 ±0.005 mm from H2O and 0.011±0.003 mm from dissolved CO2, a total rate of 0.044 ±0.008 mm yr-1. Emissions incorporated in socio-economic models underlying the RCP 8.5 and 2.6 scenarios are used along with concentration-driven CMIP5 Earth System Models results to estimate future sea-level rise from FF combustion. From 2010 to 2100, RCP8.5 and 2.6 models respectively produce 9 ±2 mmSLR and 5 ±1 mmSLR from FF H2O+CO2. For perspective, these amounts are larger than the modelled contributions from loss of glaciers in the Andes. The direct contribution of FF emissions to SLR is small (1-2%) relative to current rates and projected estimates under RCP scenarios up to 2100. The magnitude is similar to SLR estimates from other minor sources such as the melting of floating ice, land-use emissions and produced water from oil operations, none of which are currently included in SLR assessments. As uncertainties in

  18. ''Green'' path from fossil-based to hydrogen economy: An overview of carbon-neutral technologies

    Energy Technology Data Exchange (ETDEWEB)

    Muradov, Nazim Z. [Florida Solar Energy Center, University of Central Florida, Cocoa, FL 32922 (United States); Veziroglu, T. Nejat [Clean Energy Research Institute, University of Miami, Coral Gables, FL 33124 (United States)

    2008-12-15

    While the dominant role of hydrogen in a sustainable energy future is widely accepted, the strategies for the transition from fossil-based to hydrogen economy are still actively debated. This paper emphasizes the role of carbon-neutral technologies and fuels during the transition period. To satisfy the world's growing appetite for energy and keep our planet healthy, at least 10 TW (or terawatt) of carbon-free power has to be produced by mid-century. Three prominent options discussed in the literature include: decarbonization of fossil energy, nuclear energy and renewable energy sources. These options are analyzed in this paper with a special emphasis on the role of hydrogen as a carbon-free energy carrier. In particular, the authors compare various fossil decarbonization strategies and evaluate the potential of nuclear and renewable energy resources to meet the 10 TW target. An overview of state-of-the-art technologies for production of carbon-free energy carriers and transportation fuels, and the assessment of their commercial potential is provided. It is shown that neither of these three options alone could provide 10 TW of carbon-neutral power without major changes in the existing infrastructure, and/or technological breakthroughs in many areas, and/or a considerable environmental risk. The authors propose a scenario for the transition from current fossil-based to hydrogen economy that includes two key elements: (i) changing the fossil decarbonization strategy from one based on CO{sub 2} sequestration to one that involves sequestration and/or utilization of solid carbon, and (ii) producing carbon-neutral synthetic fuels from bio-carbon and hydrogen generated from water using carbon-free sources (nuclear, solar, wind, geothermal). This strategy would allow taking advantage of the existing fuel infrastructure without an adverse environmental impact, and it would secure a smooth carbon-neutral transition from fossil-based to future hydrogen economy. (author)

  19. 'Capture ready' regulation of fossil fuel power plants - Betting the UK's carbon emissions on promises of future technology

    International Nuclear Information System (INIS)

    Markusson, Nils; Haszeldine, Stuart

    2010-01-01

    Climate change legislation requires emissions reductions, but the market shows interest in investing in new fossil fuelled power plants. The question is whether capture ready policy can reconcile these interests. The term 'capture ready' has been used a few years by the UK Government when granting licences for fossil fuelled power plants, but only recently has the meaning of the term been defined. The policy has been promoted as a step towards CCS and as an insurance against carbon lock-in. This paper draws on literature on technology lock-in and on regulation of technology undergoing development. Further, versions of the capture readiness concept proposed to date are compared. Capture readiness requirements beyond the minimum criterion of space on the site for capture operations are explored. This includes integration of capture and power plant, downstream operations, overall system integration and regulation of future retrofitting. Capture readiness comes with serious uncertainties and is no guarantee that new-built fossil plants will be abatable or abated in the future. As a regulatory strategy, it has been over-promised in the UK.

  20. Sustainability of Fossil Fuels

    Science.gov (United States)

    Lackner, K. S.

    2002-05-01

    effects of injecting excess carbon into the environment need to be eliminated before fossil fuels can be considered sustainable. Sustainable fossil fuel use would likely rely on abundant, low-grade hydrocarbons like coal, tar, and shale. It would require a closed cycle approach in which carbon is extracted from the ground, processed for its energy content, and returned into safe and stable sinks for permanent disposal. Such sequestration technologies already exist and more advanced approaches that could maintain access to fossil energy for centuries are on the drawing boards. I will review these options and outline a pathway towards a zero emission fossil fuel based economy that could provide energy at prices comparable to those of today for several centuries. A successful implementation will depend not only on technological advances but also on the development of economic institutions that allow one to pay for the required carbon management. If done correctly the markets will decide whether renewable energy, or sustainable fossil energy provides a better choice.

  1. A multiresolution spatial parameterization for the estimation of fossil-fuel carbon dioxide emissions via atmospheric inversions

    Directory of Open Access Journals (Sweden)

    J. Ray

    2014-09-01

    Full Text Available The characterization of fossil-fuel CO2 (ffCO2 emissions is paramount to carbon cycle studies, but the use of atmospheric inverse modeling approaches for this purpose has been limited by the highly heterogeneous and non-Gaussian spatiotemporal variability of emissions. Here we explore the feasibility of capturing this variability using a low-dimensional parameterization that can be implemented within the context of atmospheric CO2 inverse problems aimed at constraining regional-scale emissions. We construct a multiresolution (i.e., wavelet-based spatial parameterization for ffCO2 emissions using the Vulcan inventory, and examine whether such a~parameterization can capture a realistic representation of the expected spatial variability of actual emissions. We then explore whether sub-selecting wavelets using two easily available proxies of human activity (images of lights at night and maps of built-up areas yields a low-dimensional alternative. We finally implement this low-dimensional parameterization within an idealized inversion, where a sparse reconstruction algorithm, an extension of stagewise orthogonal matching pursuit (StOMP, is used to identify the wavelet coefficients. We find that (i the spatial variability of fossil-fuel emission can indeed be represented using a low-dimensional wavelet-based parameterization, (ii that images of lights at night can be used as a proxy for sub-selecting wavelets for such analysis, and (iii that implementing this parameterization within the described inversion framework makes it possible to quantify fossil-fuel emissions at regional scales if fossil-fuel-only CO2 observations are available.

  2. Organic carbon, nitrogen and phosphorus contents of some tea soils

    International Nuclear Information System (INIS)

    Ahmed, M.S.; Zamir, M.R.; Sanauallah, A.F.M.

    2005-01-01

    Soil samples were collected from Rungicherra Tea-Estate of Moulvibazar district, Bangladesh. Organic carbon, organic matter, total nitrogen and available phosphorus content of the collected soil of different topographic positions have been determined. The experimental data have been analyzed statistically and plotted against topography and soil depth. Organic carbon and organic matter content varied from 0.79 to 1.24% and 1.37 to 2.14%. respectively. Total nitrogen and available phosphorus content of these soils varied respectively from 0.095 to 0.13% and 2.31 to 4.02 ppm. (author)

  3. Carnivore specific bone bioapatite and collagen carbon isotope fractionations: Case studies of modern and fossil grey wolf populations

    Science.gov (United States)

    Fox-Dobbs, K.; Wheatley, P. V.; Koch, P. L.

    2006-12-01

    Stable isotope analyses of modern and fossil biogenic tissues are routinely used to reconstruct present and past vertebrate foodwebs. Accurate isotopic dietary reconstructions require a consumer and tissue specific understanding of how isotopes are sorted, or fractionated, between trophic levels. In this project we address the need for carnivore specific isotope variables derived from populations that are ecologically well- characterized. Specifically, we investigate the trophic difference in carbon isotope values between mammalian carnivore (wolf) bone bioapatite and herbivore (prey) bone bioapatite. We also compare bone bioapatite and collagen carbon isotope values collected from the same individuals. We analyzed bone specimens from two modern North American grey wolf (Canis lupus) populations (Isle Royale National Park, Michigan and Yellowstone National Park, Wyoming), and the ungulate herbivores that are their primary prey (moose and elk, respectively). Because the diets of both wolf populations are essentially restricted to a single prey species, there were no confounding effects due to carnivore diet variability. We measured a trophic difference of approximately -1.3 permil between carnivore (lower value) and herbivore (higher value) bone bioapatite carbon isotope values, and an average inter-tissue difference of 5.1 permil between carnivore bone collagen (lower value) and bioapatite (higher value) carbon isotope values. Both of these isotopic differences differ from previous estimates derived from a suite of African carnivores; our carnivore-herbivore bone bioapatite carbon isotope spacing is smaller (-1.3 vs. -4.0 permil), and our carnivore collagen-bioapatite carbon difference is larger (5.1 vs. 3.0 permil). These discrepancies likely result from comparing values measured from a single hypercarnivore (wolf) to average values calculated from several carnivore species, some of which are insectivorous or partly omnivorous. The trophic and inter

  4. Do forests best mitigate CO2 emissions to the atmosphere by setting them aside for maximization of carbon storage or by management for fossil fuel substitution?

    Science.gov (United States)

    Taeroe, Anders; Mustapha, Walid Fayez; Stupak, Inge; Raulund-Rasmussen, Karsten

    2017-07-15

    Forests' potential to mitigate carbon emissions to the atmosphere is heavily debated and a key question is if forests left unmanaged to store carbon in biomass and soil provide larger carbon emission reductions than forests kept under forest management for production of wood that can substitute fossil fuels and fossil fuel intensive materials. We defined a modelling framework for calculation of the carbon pools and fluxes along the forest energy and wood product supply chains over 200 years for three forest management alternatives (FMA): 1) a traditionally managed European beech forest, as a business-as-usual case, 2) an energy poplar plantation, and 3) a set-aside forest left unmanaged for long-term storage of carbon. We calculated the cumulative net carbon emissions (CCE) and carbon parity times (CPT) of the managed forests relative to the unmanaged forest. Energy poplar generally had the lowest CCE when using coal as the reference fossil fuel. With natural gas as the reference fossil fuel, the CCE of the business-as-usual and the energy poplar was nearly equal, with the unmanaged forest having the highest CCE after 40 years. CPTs ranged from 0 to 156 years, depending on the applied model assumptions. CCE and CPT were especially sensitive to the reference fossil fuel, material alternatives to wood, forest growth rates for the three FMAs, and energy conversion efficiencies. Assumptions about the long-term steady-state levels of carbon stored in the unmanaged forest had a limited effect on CCE after 200 years. Analyses also showed that CPT was not a robust measure for ranking of carbon mitigation benefits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Dissolved organic carbon in the precipitation of Seoul, Korea: Implications for global wet depositional flux of fossil-fuel derived organic carbon

    Science.gov (United States)

    Yan, Ge; Kim, Guebuem

    2012-11-01

    Precipitation was sampled in Seoul over a one-year period from 2009 to 2010 to investigate the sources and fluxes of atmospheric dissolved organic carbon (DOC). The concentrations of DOC varied from 15 μM to 780 μM, with a volume-weighted average of 94 μM. On the basis of correlation analysis using the commonly acknowledged tracers, such as vanadium, the combustion of fossil-fuels was recognized to be the dominant source. With the aid of air mass backward trajectory analyses, we concluded that the primary fraction of DOC in our precipitation samples originated locally in Korea, albeit the frequent long-range transport from eastern and northeastern China might contribute substantially. In light of the relatively invariant organic carbon to sulfur mass ratios in precipitation over Seoul and other urban regions around the world, the global magnitude of wet depositional DOC originating from fossil-fuels was calculated to be 36 ± 10 Tg C yr-1. Our study further underscores the potentially significant environmental impacts that might be brought about by this anthropogenically derived component of organic carbon in the atmosphere.

  6. Atmospheric observations of carbon monoxide and fossil fuel CO2 emissions from East Asia

    DEFF Research Database (Denmark)

    Turnbull, Jocelyn C.; Tans, Pieter P.; Lehman, Scott J.

    2011-01-01

    Flask samples from two sites in East Asia, Tae-Ahn Peninsula, Korea (TAP), and Shangdianzi, China (SDZ), were measured for trace gases including CO2, CO and fossil fuel CO2(CO(2)ff, derived from Delta(CO2)-C-14 observations). The five-year TAP record shows high CO(2)ff when local air comes from...... the Korean Peninsula. Most samples, however, reflect air masses from Northeastern China with lower CO(2)ff. Our small set of SDZ samples from winter 2009/2010 have strongly elevated CO(2)ff. Biospheric CO2 contributes substantially to total CO2 variability at both sites, even in winter when non-fossil CO2....../ppm respectively, consistent with recent bottom-up inventory estimates and other observational studies. Locally influenced TAP samples fall into two distinct data sets, ascribed to air sourced from South Korea and North Korea. The South Korea samples have low R-CO:CO2ff of 13 +/- 3 ppb/ppm, slightly higher than...

  7. Comprehensive geobiological characterization of a bituminous carbonate facies with Ediacara-type fossils (Shibantan Member, South China)

    Science.gov (United States)

    Duda, Jan-Peter; Blumenberg, Martin; Thiel, Volker; Simon, Klaus; Zhu, Maoyan; Reitner, Joachim

    2015-04-01

    The Shibantan Member (Dengying Formation, Ediacaran Period) is one of only few carbonate settings with Ediacara-type fossils worldwide (e.g. Ding & Chen, 1981; Sun, 1986; Xiao et al., 2005; Shen et al., 2009; Chen et al., 2014). However, only little is known about the sedimentology and biogeochemistry of the environments in which these organisms throve. Here we provide a comprehensive geobiological characterization of the Shibantan Member, addressing the interplay between sedimentary and (bio-) geochemical processes. Sedimentary analysis revealed that black laminated limestones of the lower Shibantan Member were deposited after a sudden local deepening in a subtidal lower- to middle ramp environment close to the storm wave base, while the dark wavy dolomites of the upper Shibantan Member were deposited in a subtidal middle ramp environment between storm- and fair weather wave base. Sedimentation in the Shibantan basin was generally highly dynamic as evidenced by a distinct slumping horizon and mass-flow deposits that were possibly due to synsedimentary tectonic processes. The microbial-mat associated biota including Ediacara-type fossils is restricted to the lower Shibantan Member. Sedimentary analysis of this part reveals a close relationship between autochthonous mat growth and allochthonous and/or para-autochthonous event deposition. During deposition of the lower Shibantan Member the water column was probably temporarily stratified, with a sub- to anoxic water layer (evidenced by Ni/Co-, V/(V+Ni) and V/Sc ratios) overlain by a oxygenated upper layer (evidenced by negative Ce anomalies and low V/Cr ratios). However, such stratification was not permanent, as mixing by storm events is evidenced by hummocky cross stratification structures. 13C-enrichments in carbonates of the Lower Shibantan Member (δ13C = +3.3 to +4.0o VPDB) together with 13C-depletions of syngenetic n-alkanes cleaved from the respective extraction residue using catalytic hydropyrolysis (HyPy;

  8. Determination of free carbon content in boron carbide ceramic powders

    International Nuclear Information System (INIS)

    Castro, A.R.M. de; Lima, N.B. de; Paschoal, J.O.A.

    1990-01-01

    Boron carbide is a ceramic material of technological importance due to its hardness and high chemical and thermal stabilities. Free carbon is always found as a process dependent impurity in boron carbide. The development of procedures for its detection is required because its presence leads to a degradation of the boron carbide properties. In this work, several procedures for determining free carbon content in boron carbide specimens are reported and discussed for comparison purposes. (author) [pt

  9. An optimization model for carbon capture & storage/utilization vs. carbon trading: A case study of fossil-fired power plants in Turkey.

    Science.gov (United States)

    Ağralı, Semra; Üçtuğ, Fehmi Görkem; Türkmen, Burçin Atılgan

    2018-06-01

    We consider fossil-fired power plants that operate in an environment where a cap and trade system is in operation. These plants need to choose between carbon capture and storage (CCS), carbon capture and utilization (CCU), or carbon trading in order to obey emissions limits enforced by the government. We develop a mixed-integer programming model that decides on the capacities of carbon capture units, if it is optimal to install them, the transportation network that needs to be built for transporting the carbon captured, and the locations of storage sites, if they are decided to be built. Main restrictions on the system are the minimum and maximum capacities of the different parts of the pipeline network, the amount of carbon that can be sold to companies for utilization, and the capacities on the storage sites. Under these restrictions, the model aims to minimize the net present value of the sum of the costs associated with installation and operation of the carbon capture unit and the transportation of carbon, the storage cost in case of CCS, the cost (or revenue) that results from the emissions trading system, and finally the negative revenue of selling the carbon to other entities for utilization. We implement the model on General Algebraic Modeling System (GAMS) by using data associated with two coal-fired power plants located in different regions of Turkey. We choose enhanced oil recovery (EOR) as the process in which carbon would be utilized. The results show that CCU is preferable to CCS as long as there is sufficient demand in the EOR market. The distance between the location of emission and location of utilization/storage, and the capacity limits on the pipes are an important factor in deciding between carbon capture and carbon trading. At carbon prices over $15/ton, carbon capture becomes preferable to carbon trading. These results show that as far as Turkey is concerned, CCU should be prioritized as a means of reducing nation-wide carbon emissions in an

  10. Content of nitrogen in waste petroleum carbon for steel industries

    International Nuclear Information System (INIS)

    Rios, R.O; Jimenez, A.F; Szieber, C.W; Banchik, A.D

    2004-01-01

    Steel industries use refined carbon as an alloy for steel production. This alloy is produced from waste carbon from the distillation of the petroleum. The refined carbon, called recarburizer, is obtained by calcination at high temperature. Under these thermal conditions the organic molecules decompose and a fraction of the N 2 , S and H 2 , volatile material and moisture are released; while the carbon tends to develop a crystalline structure similar to graphite's. The right combination of calcinations temperature and time in the furnace can optimize the quality of the resulting product. The content of S and N 2 has to be minimized for the use of calcined carbon in the steel industry. Nitrogen content should be reduced by two orders of magnitude, from 1% - 2% down to hundreds of ppm by weight. This work describes the activities undertaken to obtain calcined coke from petroleum from crude oil carbon that satisfies the requirements of the Mercosur standard 02:00-169 (Pending) for use as a carborizer in steels industries. To satisfy the requirements of the Mercosur standards NM 236:00 IRAM-IAS-NM so that graphite is used as a carburizer a content of 300 ppm maximum weight of nitrogen has to be obtained. So the first stage in this development is to define a production process for supplying calcined coke in the range of nitrogen concentrations required by the Mercosur standards (CW)

  11. Unique case of fatal carbon monoxide poisoning in the absence of a combustible fossil fuel.

    Science.gov (United States)

    Morgan, D R; Poon, P; Titley, J; Jagger, S F; Rutty, G N

    2001-09-01

    A 37-year-old man died as a result of exposure to carbon monoxide within an apartment. An investigation of the apartment showed no gas appliances or gas supply to the apartment and no evidence of any combustion event to any part of the apartment or roof space. Inhalation of dichloromethane was excluded. Heating to the apartment was found to be via an electrical storage heater, the examination of which revealed that the cast-iron core and insulating material showed evidence of heat damage with significant areas devoid of carbon. This electric storage heater is hypothesized to be the source of carbon for the fatal production of carbon monoxide within the apartment.

  12. Stable isotope compositions of organic carbon and contents of ...

    African Journals Online (AJOL)

    The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid ...

  13. Method for creating high carbon content products from biomass oil

    Science.gov (United States)

    Parker, Reginald; Seames, Wayne

    2012-12-18

    In a method for producing high carbon content products from biomass, a biomass oil is added to a cracking reactor vessel. The biomass oil is heated to a temperature ranging from about 100.degree. C. to about 800.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to crack the biomass oil. Tar is separated from the cracked biomass oil. The tar is heated to a temperature ranging from about 200.degree. C. to about 1500.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to reduce the tar to a high carbon content product containing at least about 50% carbon by weight.

  14. Determination of wood burning and fossil fuel contribution of black carbon at Delhi, India using aerosol light absorption technique.

    Science.gov (United States)

    Tiwari, S; Pipal, A S; Srivastava, A K; Bisht, D S; Pandithurai, G

    2015-02-01

    A comprehensive measurement program of effective black carbon (eBC), fine particle (PM2.5), and carbon monoxide (CO) was undertaken during 1 December 2011 to 31 March 2012 (winter period) in Delhi, India. The mean mass concentrations of eBC, PM2.5, and CO were recorded as 12.1 ± 8.7 μg/m(3), 182.75 ± 114.5 μg/m(3), and 3.41 ± 1.6 ppm, respectively, during the study period. Also, the absorption Angstrom exponent (AAE) was estimated from eBC and varied from 0.38 to 1.29 with a mean value of 1.09 ± 0.11. The frequency of occurrence of AAE was ~17 % less than unity whereas ~83 % greater than unity was observed during the winter period in Delhi. The mass concentrations of eBC were found to be higher by ~34 % of the average value of eBC (12.1 μg/m(3)) during the study period. Sources of eBC were estimated, and they were ~94 % from fossil fuel (eBCff) combustion whereas only 6 % was from wood burning (eBCwb). The ratio between eBCff and eBCwb was 15, which indicates a higher impact from fossil fuels compared to biomass burning. When comparing eBCff during day and night, a factor of three higher concentrations was observed in nighttime than daytime, and it is due to combustion of fossil fuel (diesel vehicle emission) and shallow boundary layer conditions. The contribution of eBCwb in eBC was higher between 1800 and 2100 hours due to burning of wood/biomass. A significant correlation between eBC and PM2.5 (r = 0.78) and eBC and CO (r = 0.46) indicates the similarity in location sources. The mass concentration of eBC was highest (23.4 μg/m(3)) during the month of December when the mean visibility (VIS) was lowest (1.31 km). Regression analysis among wind speed (WS), VIS, soot particles, and CO was studied, and significant negative relationships were seen between VIS and eBC (-0.65), eBCff (-0.66), eBCwb (-0.34), and CO (-0.65); however, between WS and eBC (-0.68), eBCff (-0.67), eBCwb (-0.28), and CO (-0.53). The regression analysis indicated

  15. Improving the Carbon Dioxide Emission Estimates from the Combustion of Fossil Fuels in California

    Energy Technology Data Exchange (ETDEWEB)

    de la Rue du Can, Stephane; Wenzel, Tom; Price, Lynn

    2008-08-13

    Central to any study of climate change is the development of an emission inventory that identifies and quantifies the State's primary anthropogenic sources and sinks of greenhouse gas (GHG) emissions. CO2 emissions from fossil fuel combustion accounted for 80 percent of California GHG emissions (CARB, 2007a). Even though these CO2 emissions are well characterized in the existing state inventory, there still exist significant sources of uncertainties regarding their accuracy. This report evaluates the CO2 emissions accounting based on the California Energy Balance database (CALEB) developed by Lawrence Berkeley National Laboratory (LBNL), in terms of what improvements are needed and where uncertainties lie. The estimated uncertainty for total CO2 emissions ranges between -21 and +37 million metric tons (Mt), or -6percent and +11percent of total CO2 emissions. The report also identifies where improvements are needed for the upcoming updates of CALEB. However, it is worth noting that the California Air Resources Board (CARB) GHG inventory did not use CALEB data for all combustion estimates. Therefore the range in uncertainty estimated in this report does not apply to the CARB's GHG inventory. As much as possible, additional data sources used by CARB in the development of its GHG inventory are summarized in this report for consideration in future updates to CALEB.

  16. Reforming fossil fuel use : the merits, costs and risks of carbon dioxide capture and storage

    NARCIS (Netherlands)

    Damen, Kay J.

    2007-01-01

    The sense of urgency in achieving large reductions in anthropogenic CO2 emissions has increased the interest in carbon dioxide capture and storage (CCS). CCS can be defined as the separation and capture of CO2 produced at large stationary sources, followed by transport and storage in geological

  17. Integrating biorefinery and farm biogeochemical cycles offsets fossil energy and mitigates soil carbon losses

    Science.gov (United States)

    Crop residues are potentially significant sources of feedstock for biofuel production in the US. However there are concerns with maintaining the environmental functions of these residues while also serving as a feedstock for biofuel production. Maintaining soil organic carbon (SOC) along with its fu...

  18. Quantification of diagenetic overprint processes deduced from fossil carbonate shells and laboratory-based hydrothermal alteration experiments

    Science.gov (United States)

    Griesshaber, Erika; Casella, Laura; Mavromatis, Vasileios; Dietzel, Martin; Immenhauser, Adrian; Schmahl, Wolfgang

    2016-04-01

    Benthic and nektonic marine biogenic carbonate archives represent the foundation of numerous studies aiming at reconstructions of past climate dynamics and environmental change. However, living organisms are not in thermodynamic equilibrium and create local chemical environments where physiologic processes such as biomineralization takes place. After the death of the organism the former physiologic disequilibrium conditions are not sustained any more and all biological tissues are altered by equilibration according to the surrounding environment: diagenesis. With increasing diagenetic alteration, the biogenic structure and fingerprint fades away and is replaced by inorganic features. Thus, recrystallization of organism-specific microstructure is a clear indicator for diagenetic overprint. Microstructural data, which mirror recrystallization, are of great value for interpreting geochemical proxies for paleo-environment reconstruction. Despite more than a century of research dealing with carbonate diagenesis, many of the controlling processes and factors are only understood in a qualitative manner. One of the main issues is that diagenetically altered carbonates are usually present as the product of a complex preceding diagenetic pathway with an unknown number of intermediate steps. In this contribution we present and discuss laboratory based alteration experiments with the aim to investigate time-series data sets in a controlled manner. We conducted hydrothermal alteration experiments with modern Arctica islandica (bivalvia) and Notosaria nigricans (brachiopoda) in order to mimic diagenetic overprint. We explore first the potential of electron backscattered diffraction (EBSD) measurements together with statistical data evaluation as a tool to quantify diagenetic alteration of carbonate skeletons. Subsequently, we compare microstructural patterns obtained from experimentally altered shell material with those of fossil specimens that have undergone variable degrees of

  19. Non-energy use of fossil fuels and resulting carbon dioxide emissions: bottom-up estimates for the world as a whole and for major developing countries

    NARCIS (Netherlands)

    Weiss, M.; Neelis, M.L.; Blok, K.; Patel, M.K.

    2009-01-01

    We present and apply a simple bottom–up model for estimating non-energy use of fossil fuels and resulting CO2 (carbon dioxide) emissions.We apply this model for the year 2000: (1) to the world as a whole, (2) to the aggregate of Annex I countries and non-Annex I countries, and (3) to the ten

  20. Decarbonisation of fossil energy via methane pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kreysa, G.; Agar, D.W.; Schultz, I. [Technische Univ. Dortmund (Germany)

    2010-12-30

    Despite the rising consumption of energy over the last few decades, the proven reserves of fossil fuels have steadily increased. Additionally, there are potentially tremendous reserves of methane hydrates available, which remain to be exploited. The use of fossil energy sources is thus increasingly being dictated less by supply than by the environmental concerns raised by climate change. In the context of the decarbonisation of the global energy system that this has stimulated, new means must be explored for using methane as energy source. Noncatalytic thermal pyrolysis of methane is proposed here as a promising concept for utilising methane with low to zero carbon dioxide emissions. Following cracking, only the energy content of the hydrogen is used, while the carbon can be stored safely and retrievably in disused coal mines. The thermodynamics and different process engineering concepts for the technical realisation of such a carbon moratorium technology are discussed. The possible contribution of methane pyrolysis to carbon negative geoengineering is also addressed. (orig.)

  1. Fossil Explorers

    Science.gov (United States)

    Moran, Sean; McLaughlin, Cheryl; MacFadden, Bruce; Jacobbe, Elizabeth; Poole, Michael

    2015-01-01

    Many young learners are fascinated with fossils, particularly charismatic forms such as dinosaurs and giant sharks. Fossils provide tangible, objective evidence of life that lived millions of years ago. They also provide a timescale of evolution not typically appreciated by young learners. Fossils and the science of paleontology can, therefore,…

  2. Determination of contents of carbonate and hydrogen carbonate in solutions for alkaline leading of uranium ores

    International Nuclear Information System (INIS)

    Radil, V.

    1988-01-01

    The new analytical method is based on the determination of the molar ratio carbonate - hydrogen carbonate using the measured concentration of hydrogen ions, the determination of the dissociation constant of carbonic acid for different values of ionic strength. The concentration of hydrogen ions was measured with a Metrohm 632 pH meter with the use of a combined glass electrode. The content of total carbonate carbon was determined coulometrically and the uranium content was determined by extraction with tributyl phosphate and by spectrometry of the complex of uranyl ions with Arsenazo III. Model solutions were used for the experiments which contained a high concentration of sulfate ions, thiosulfate ions, uranium and various proportions of carbonate and hydrogen carbonate. The composition of the individual samples of the extraction solutions are tabulated. The calibration was made of the glass combined electrode at different ionic strength, the values determined of dissociation constants of carbonic acid for different ionic strength. The mathematical procedure is described for the calculation of molar concentrations of carbonate and hudrogen carbonate and the results are presented of the analysis of model solutions. (E.S.). 5 tabs., 1 fig., 5 refs

  3. Assessing Uncertainties in Gridded Emissions: A Case Study for Fossil Fuel Carbon Dioxide (FFCO2) Emission Data

    Science.gov (United States)

    Oda, T.; Ott, L.; Lauvaux, T.; Feng, S.; Bun, R.; Roman, M.; Baker, D. F.; Pawson, S.

    2017-01-01

    Fossil fuel carbon dioxide (CO2) emissions (FFCO2) are the largest input to the global carbon cycle on a decadal time scale. Because total emissions are assumed to be reasonably well constrained by fuel statistics, FFCO2 often serves as a reference in order to deduce carbon uptake by poorly understood terrestrial and ocean sinks. Conventional atmospheric CO2 flux inversions solve for spatially explicit regional sources and sinks and estimate land and ocean fluxes by subtracting FFCO2. Thus, errors in FFCO2 can propagate into the final inferred flux estimates. Gridded emissions are often based on disaggregation of emissions estimated at national or regional level. Although national and regional total FFCO2 are well known, gridded emission fields are subject to additional uncertainties due to the emission disaggregation. Assessing such uncertainties is often challenging because of the lack of physical measurements for evaluation. We first review difficulties in assessing uncertainties associated with gridded FFCO2 emission data and present several approaches for evaluation of such uncertainties at multiple scales. Given known limitations, inter-emission data differences are often used as a proxy for the uncertainty. The popular approach allows us to characterize differences in emissions, but does not allow us to fully quantify emission disaggregation biases. Our work aims to vicariously evaluate FFCO2 emission data using atmospheric models and measurements. We show a global simulation experiment where uncertainty estimates are propagated as an atmospheric tracer (uncertainty tracer) alongside CO2 in NASA's GEOS model and discuss implications of FFCO2 uncertainties in the context of flux inversions. We also demonstrate the use of high resolution urban CO2 simulations as a tool for objectively evaluating FFCO2 data over intense emission regions. Though this study focuses on FFCO2 emission data, the outcome of this study could also help improve the knowledge of similar

  4. Denuded zone in Czochralski silicon wafer with high carbon content

    International Nuclear Information System (INIS)

    Chen Jiahe; Yang Deren; Ma Xiangyang; Que Duanlin

    2006-01-01

    The thermal stability of the denuded zone (DZ) created by high-low-high-temperature annealing in high carbon content (H[C]) and low carbon content (L[C]) Czochralski silicon (Cz-Si) has been investigated in a subsequent ramping and isothermal 1050 deg. C annealing. The tiny oxygen precipitates which might occur in the DZ were checked. It was found in the L[C] Cz-Si that the DZ shrank and the density of bulk micro-defects (BMDs) reduced with the increase of time spent at 1050 deg. C. Also, the DZs above 15 μm of thickness present in the H[C] Cz-Si wafers continuously and the density and total volume of BMDs first decreased then increased and finally decreased again during the treatments. Moreover, tiny oxygen precipitates were hardly generated inside the DZs, indicating that H[C] Cz-Si wafers could support the fabrication of integrated circuits

  5. Denuded zone in Czochralski silicon wafer with high carbon content

    Science.gov (United States)

    Chen, Jiahe; Yang, Deren; Ma, Xiangyang; Que, Duanlin

    2006-12-01

    The thermal stability of the denuded zone (DZ) created by high-low-high-temperature annealing in high carbon content (H[C]) and low carbon content (L[C]) Czochralski silicon (Cz-Si) has been investigated in a subsequent ramping and isothermal 1050 °C annealing. The tiny oxygen precipitates which might occur in the DZ were checked. It was found in the L[C] Cz-Si that the DZ shrank and the density of bulk micro-defects (BMDs) reduced with the increase of time spent at 1050 °C. Also, the DZs above 15 µm of thickness present in the H[C] Cz-Si wafers continuously and the density and total volume of BMDs first decreased then increased and finally decreased again during the treatments. Moreover, tiny oxygen precipitates were hardly generated inside the DZs, indicating that H[C] Cz-Si wafers could support the fabrication of integrated circuits.

  6. Blue carbon content of mangrove vegetation in Subang district

    Science.gov (United States)

    Nurruhwati, I.; Purwita, S. D.; Sunarto; Zahidah

    2018-04-01

    The purpose of this research was to know the carbon content of mangrove parts such as leave, stems and roots and to know its ability to absorb carbondioxide (CO2). The research was conducted in 27th April until 16th May 2017 in Blanakan Village, Langensari Village and Jayamukti Village. The samples are dried at Pilotplane Laboratory Faculty of Industrial Engineering Padjadjaran University. The method in this research is explorative survey method. The results showed that there were two dominant mangroves species in three research stations, they are Avicennia marina and Rhizophora mucronata. Index of Important value of each mangrove type on the three stations in the medium criterion with a range of values is 106,86 %- 193,13 %. The highest carbon content was found in Rhizophora mucronata at station 1 (93,43 %) which was equivalent with 342,87 % absorption of CO2 which was The lowest carbon content was in Avicennia marina at station 1 (67,49 %) which was equivalent with 247,70 % absorption of CO2.

  7. Argon laser induced changes to the carbonate content of enamel

    International Nuclear Information System (INIS)

    Ziglo, M.J.; Nelson, A.E.; Heo, G.; Major, P.W.

    2009-01-01

    Argon laser irradiation can be used to cure orthodontic brackets onto teeth in significantly less time than conventional curing lights. In addition, it has been shown that the argon laser seems to impart a demineralization resistance to the enamel. The purpose of this study was to use surface science techniques to ascertain if this demineralization resistance is possibly a result of a decrease in the carbonate content of enamel. Eleven mandibular third molars previously scheduled for extraction were collected and used in the present study. The teeth were sectioned in two and randomly assigned to either the argon laser (457-502 nm; 250 mW cm -2 ) or the control (no treatment) group. The sections assigned to the argon laser group were cured for 10 s and analyzed. To exaggerate any potential changes the experimental sections were then exposed to a further 110 s of argon laser irradiation. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results showed no statistically significant change in the carbonate content of enamel after argon laser irradiation (p > 0.05). Thus, it is suggested that any demineralization resistance imparted to the enamel surface by argon laser irradiation is not due to alterations in carbonate content.

  8. Argon laser induced changes to the carbonate content of enamel

    Energy Technology Data Exchange (ETDEWEB)

    Ziglo, M.J. [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta, Private Practice, Regina, Saskatchewan (Canada); Nelson, A.E., E-mail: aenelson@dow.com [Department of Chemical and Materials Engineering, Faculty of Engineering, University of Alberta (Canada); Heo, G.; Major, P.W. [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta (Canada)

    2009-05-15

    Argon laser irradiation can be used to cure orthodontic brackets onto teeth in significantly less time than conventional curing lights. In addition, it has been shown that the argon laser seems to impart a demineralization resistance to the enamel. The purpose of this study was to use surface science techniques to ascertain if this demineralization resistance is possibly a result of a decrease in the carbonate content of enamel. Eleven mandibular third molars previously scheduled for extraction were collected and used in the present study. The teeth were sectioned in two and randomly assigned to either the argon laser (457-502 nm; 250 mW cm{sup -2}) or the control (no treatment) group. The sections assigned to the argon laser group were cured for 10 s and analyzed. To exaggerate any potential changes the experimental sections were then exposed to a further 110 s of argon laser irradiation. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results showed no statistically significant change in the carbonate content of enamel after argon laser irradiation (p > 0.05). Thus, it is suggested that any demineralization resistance imparted to the enamel surface by argon laser irradiation is not due to alterations in carbonate content.

  9. Argon laser induced changes to the carbonate content of enamel

    Science.gov (United States)

    Ziglo, M. J.; Nelson, A. E.; Heo, G.; Major, P. W.

    2009-05-01

    Argon laser irradiation can be used to cure orthodontic brackets onto teeth in significantly less time than conventional curing lights. In addition, it has been shown that the argon laser seems to impart a demineralization resistance to the enamel. The purpose of this study was to use surface science techniques to ascertain if this demineralization resistance is possibly a result of a decrease in the carbonate content of enamel. Eleven mandibular third molars previously scheduled for extraction were collected and used in the present study. The teeth were sectioned in two and randomly assigned to either the argon laser (457-502 nm; 250 mW cm -2) or the control (no treatment) group. The sections assigned to the argon laser group were cured for 10 s and analyzed. To exaggerate any potential changes the experimental sections were then exposed to a further 110 s of argon laser irradiation. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results showed no statistically significant change in the carbonate content of enamel after argon laser irradiation ( p > 0.05). Thus, it is suggested that any demineralization resistance imparted to the enamel surface by argon laser irradiation is not due to alterations in carbonate content.

  10. Trade-off in emissions of acid gas pollutants and of carbon dioxide in fossil fuel power plants with carbon capture

    International Nuclear Information System (INIS)

    Tzimas, Evangelos; Mercier, Arnaud; Cormos, Calin-Cristian; Peteves, Stathis D.

    2007-01-01

    This paper investigates the impact of capture of carbon dioxide (CO 2 ) from fossil fuel power plants on the emissions of nitrogen oxides (NO X ) and sulphur oxides (SO X ), which are acid gas pollutants. This was done by estimating the emissions of these chemical compounds from natural gas combined cycle and pulverized coal plants, equipped with post-combustion carbon capture technology for the removal of CO 2 from their flue gases, and comparing them with the emissions of similar plants without CO 2 capture. The capture of CO 2 is not likely to increase the emissions of acid gas pollutants from individual power plants; on the contrary, some NO X and SO X will also be removed during the capture of CO 2 . The large-scale implementation of carbon capture is however likely to increase the emission levels of NO X from the power sector due to the reduced efficiency of power plants equipped with capture technologies. Furthermore, SO X emissions from coal plants should be decreased to avoid significant losses of the chemicals that are used to capture CO 2 . The increase in the quantity of NO X emissions will be however low, estimated at 5% for the natural gas power plant park and 24% for the coal plants, while the emissions of SO X from coal fired plants will be reduced by as much as 99% when at least 80% of the CO 2 generated will be captured

  11. Activated carbon oxygen content influence on water and surfactant adsorption.

    Science.gov (United States)

    Pendleton, Phillip; Wu, Sophie Hua; Badalyan, Alexander

    2002-02-15

    This research investigates the adsorption properties of three activated carbons (AC) derived from coconut, coal, and wood origin. Each carbon demonstrates different levels of resistance to 2 M NaOH treatment. The coconut AC offers the greatest and wood AC the least resistance. The influence of base treatment is mapped in terms of its effects on specific surface area, micropore volume, water adsorption, and dodecanoic acid adsorption from both water and 2 M NaOH solution. A linear relationship exists between the number of water molecules adsorbed at the B-point of the water adsorption isotherm and the oxygen content determined from elemental analysis. Surfactant adsorption isotherms from water and 2 M NaOH indicate that the AC oxygen content effects a greater dependence on affinity for surfactant than specific surface area and micropore volume. We show a linear relationship between the plateau amount of surfactant adsorbed and the AC oxygen content in both water and NaOH phases. The higher the AC oxygen content, the lower the amount of surfactant adsorbed. In contrast, no obvious relationship could be drawn between the surfactant amount adsorbed and the surface area.

  12. Substitutability of Electricity and Renewable Materials for Fossil Fuels in a Post-Carbon Economy

    Directory of Open Access Journals (Sweden)

    Antonio García-Olivares

    2015-11-01

    Full Text Available A feasible way to avoid the risk of energy decline and combat climate change is to build a 100% renewable global energy mix. However, a globally electrified economy cannot grow much above 12 electric terawatts without putting pressure on the limits of finite mineral reserves. Here we analyze whether 12 TW of electricity and 1 TW of biomass (final power will be able to fuel a future post-carbon economy that can provide similar services to those of a contemporary economy. Contrarily to some pessimistic expectations, this analysis shows that the principle economic processes can be replaced with sustainable alternatives based on electricity, charcoal, biogas and hydrogen. Furthermore, those services that cannot be replaced are not as crucial so as to cause a return to a pre-industrial society. Even so, land transport and aviation are at the limit of what is sustainable, outdoor work should be reorganized, metal primary production should be based on hydrogen reduction when possible, mineral production should be increasingly based on recycling, the petrochemical industry should shrink to a size of 40%–43% of the 2012 petrochemical sector, i.e., a size similar to that the sector had in 1985–1986, and agriculture may require organic farming methods to be sustainable.

  13. Nitrogen isotopic analysis of carbonate-bound organic matter in modern and fossil fish otoliths

    Science.gov (United States)

    Lueders-Dumont, Jessica A.; Wang, Xingchen T.; Jensen, Olaf P.; Sigman, Daniel M.; Ward, Bess B.

    2018-03-01

    The nitrogen isotopic composition (δ15N) of otolith-bound organic matter (OM) is a potential source of information on dietary history of bony fishes. In contrast to the δ15N of white muscle tissue, the most commonly used tissue for ecological studies, the δ15N of otolith-bound OM (δ15Noto) provides a record of whole life history. More importantly, δ15Noto can be measured in contexts where tissue is not available, for example, in otolith archives and sedimentary deposits. The utility and robustness of otolith δ15N analysis was heretofore limited by the low N content of otoliths, which precluded the routine measurement of individual otoliths as well as the thorough cleaning of otolith material prior to analysis. Here, we introduce a new method based on oxidation to nitrate followed by bacterial conversion to N2O. The method requires 200-fold less N compared to traditional combustion approaches, allowing for thorough pre-cleaning and replicated analysis of individual otoliths of nearly any size. Long term precision of δ15Noto is 0.3‰. Using an internal standard of Atlantic cod (Gadus morhua) otoliths, we examine the parameters of the oxidative cleaning step with regard to oxidant (potassium persulfate and sodium hypochlorite), temperature, and time. We also report initial results that verify the usefulness of δ15Noto for ecological studies. For three salmonid species, left and right otoliths from the same fish are indistinguishable. We find that the δ15Noto of pink salmon (Oncorhynchus gorbuscha) is related to the size of the fish for this species. We find that intra-cohort δ15Noto standard deviation for wild pink salmon, farmed brown trout (Salmo trutta), and farmed rainbow trout (Oncorhynchus mykiss) are all 0.4‰ or less, suggesting that δ15Noto will be valuable for population-level studies. Lastly, our protocol yields reproducible data for both δ15Noto and otolith N content in 17th century Atlantic cod otoliths. We find that 17th century cod are

  14. Carbon dioxide effects: research and assessment program. Workshop on the global effects of carbon dioxide from fossil fuels

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, W P; Machta, L [eds.

    1979-05-01

    Current knowledge of the CO/sub 2/ cycle and the consequences of increases in CO/sub 2/ content of the atmosphere are discussed. Significant gaps in our understanding are identified and actions to fill these gaps are recommended. Reports on panel discussions on the following topics are presented: atmospheric CO/sub 2/, biological effects, ocean geochemistry, and climate effects. Each invited paper has been abstracted and indexed for ERA/EDB. (JGB)

  15. Security of supply: a neglected fossil fuel externality

    International Nuclear Information System (INIS)

    Cavallo, A.J.

    1995-01-01

    Various groups have attempted to set a monetary value on the externalities of fossil fuel usage based on damages caused by emissions of particulates, sulfur dioxide, and oxides of nitrogen and carbon. One externality that has been neglected in this type of analysis, however, is the cost of maintaining a secure supply of fossil fuels. Military expenditures for this purpose are relatively easy to quantify based on US Department of Defense and Office of Management and Budget figures, and amount to between $1 and more than $3 per million Btu, based on total fossil fuel consumption in the US. Open acknowledgment of such expenses would, at the very least, have a profound effect on the perceived competitiveness of all non-fossil fuel technologies. It should also provide a simple and easily comprehended rationale for an energy content (Btu) charge on all fossil fuels. (Author)

  16. Validity of estimating the organic carbon content of basin sediment using color measurements

    International Nuclear Information System (INIS)

    Sasaki, Toshinori; Sugai, Toshihiko; Ogami, Takashi; Yanagida, Makoto; Yasue, Ken-ichi

    2010-01-01

    Psychometric lightness (L* value) measured by a colorimeter offers a rapid means of obtaining the organic carbon content of sediment. We measured peat and lacustrine sediments covering the past 300 ka - 106 samples for L* value and 197 samples for organic carbon content. L* values are highly correlated with organic carbon contents. Therefore, L* values are a convenient alternative to measuring organic carbon contents. (author)

  17. Uranium in fossil bones

    International Nuclear Information System (INIS)

    Koul, S.L.

    1978-01-01

    An attempt has been made to determine the uranium content and thus the age of certain fossil bones Haritalyangarh (Himachal Pradesh), India. The results indicate that bones rich in apatite are also rich in uranium, and that the radioactivity is due to radionuclides in the uranium series. The larger animals apparently have a higher concentration of uranium than the small. The dating of a fossil jaw (elephant) places it in the Pleistocene. (Auth.)

  18. Modelling and mapping the topsoil organic carbon content for Tanzania

    Science.gov (United States)

    Kempen, Bas; Kaaya, Abel; Ngonyani Mhaiki, Consolatha; Kiluvia, Shani; Ruiperez-Gonzalez, Maria; Batjes, Niels; Dalsgaard, Soren

    2014-05-01

    Soil organic carbon (SOC), held in soil organic matter, is a key indicator of soil health and plays an important role in the global carbon cycle. The soil can act as a net source or sink of carbon depending on land use and management. Deforestation and forest degradation lead to the release of vast amounts of carbon from the soil in the form of greenhouse gasses, especially in tropical countries. Tanzania has a high deforestation rate: it is estimated that the country loses 1.1% of its total forested area annually. During 2010-2013 Tanzania has been a pilot country under the UN-REDD programme. This programme has supported Tanzania in its initial efforts towards reducing greenhouse gas emission from forest degradation and deforestation and towards preserving soil carbon stocks. Formulation and implementation of the national REDD strategy requires detailed information on the five carbon pools among these the SOC pool. The spatial distribution of SOC contents and stocks was not available for Tanzania. The initial aim of this research, was therefore to develop high-resolution maps of the SOC content for the country. The mapping exercise was carried out in a collaborative effort with four Tanzanian institutes and data from the Africa Soil Information Service initiative (AfSIS). The mapping exercise was provided with over 3200 field observations on SOC from four sources; this is the most comprehensive soil dataset collected in Tanzania so far. The main source of soil samples was the National Forest Monitoring and Assessment (NAFORMA). The carbon maps were generated by means of digital soil mapping using regression-kriging. Maps at 250 m spatial resolution were developed for four depth layers: 0-10 cm, 10-20 cm, 20-30 cm, and 0-30 cm. A total of 37 environmental GIS data layers were prepared for use as covariates in the regression model. These included vegetation indices, terrain parameters, surface temperature, spectral reflectances, a land cover map and a small

  19. Fossil Fuels.

    Science.gov (United States)

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  20. Fossil Crinoids

    Science.gov (United States)

    Hess, Hans; Ausich, William I.; Brett, Carlton E.; Simms, Michael J.

    2003-01-01

    Crinoids have graced the oceans for more than 500 million years. Among the most attractive fossils, crinoids had a key role in the ecology of marine communities through much of the fossil record, and their remains are prominent rock forming constituents of many limestones. This is the first comprehensive volume to bring together their form and function, classification, evolutionary history, occurrence, preservation and ecology. The main part of the book is devoted to assemblages of intact fossil crinoids, which are described in their geological setting in twenty-three chapters ranging from the Ordovician to the Tertiary. The final chapter deals with living sea lilies and feather stars. The volume is exquisitely illustrated with abundant photographs and line drawings of crinoids from sites around the world. This authoritative account recreates a fascinating picture of fossil crinoids for paleontologists, geologists, evolutionary and marine biologists, ecologists and amateur fossil collectors.

  1. The Hestia Project: High Spatial Resolution Fossil Fuel Carbon Dioxide Emissions Quantification at Hourly Scale in Indianapolis, USA

    Science.gov (United States)

    Zhou, Y.; Gurney, K. R.

    2009-12-01

    In order to advance the scientific understanding of carbon exchange with the land surface and contribute to sound, quantitatively-based U.S. climate change policy interests, quantification of greenhouse gases emissions drivers at fine spatial and temporal scales is essential. Quantification of fossil fuel CO2 emissions, the primary greenhouse gases, has become a key component to cost-effective CO2 emissions mitigation options and a carbon trading system. Called the ‘Hestia Project’, this pilot study generated CO2 emissions down to high spatial resolution and hourly scale for the greater Indianapolis region in the USA through the use of air quality and traffic monitoring data, remote sensing, GIS, and building energy modeling. The CO2 emissions were constructed from three data source categories: area, point, and mobile. For the area source emissions, we developed an energy consumption model using DOE/EIA survey data on building characteristics and energy consumption. With the Vulcan Project’s county-level CO2 emissions and simulated building energy consumption, we quantified the CO2 emissions for each individual building by allocating Vulcan emissions to roughly 50,000 structures in Indianapolis. The temporal pattern of CO2 emissions in each individual building was developed based on temporal patterns of energy consumption. The point sources emissions were derived from the EPA National Emissions Inventory data and effluent monitoring of electricity producing facilities. The mobile source CO2 emissions were estimated at the month/county scale using the Mobile6 combustion model and the National Mobile Inventory Model database. The month/county scale mobile source CO2 emissions were downscaled to the “native” spatial resolution of road segments every hour using a GIS road atlas and traffic monitoring data. The result is shown in Figure 1. The resulting urban-scale inventory can serve as a baseline of current CO2 emissions and should be of immediate use to

  2. Carbon dioxide emissions from fossil fuel consumption and cement manufacture, 1751-1991; and an estimate of their isotopic composition and latitudinal distribution

    Energy Technology Data Exchange (ETDEWEB)

    Andres, R.J.; Marland, G.; Boden, T.; Bischof, S.

    1994-10-01

    This work briefly discusses four of the current research emphases at Oak Ridge National Laboratory regarding the emission of carbon dioxide (CO{sub 2}) from fossil fuel consumption, natural gas flaring and cement manufacture. These emphases include: (1) updating the 1950 to present time series of CO{sub 2} emissions from fossil fuel consumption and cement manufacture, (2) extending this time series back to 1751, (3) gridding the data at 1{sup 0} by 1{sup 0} resolution, and (4) estimating the isotopic signature of these emissions. In 1991, global emissions of CO{sub 2} from fossil fuel and cement increased 1.5% over 1990 levels to 6188 {times} 10{sup 6} metric tonnes C. The Kuwaiti oil fires can account for all of the increase. Recently published energy data (Etemad et al., 1991) allow extension of the CO emissions time series back to 1751. Preliminary examination shows good agreement with two other, but shorter, energy time series. A latitudinal distribution of carbon emissions is being completed. A southward shift in the major mass of CO{sub 2} emissions is occurring from European-North American latitudes towards central-southeast Asian latitudes, reflecting the growth of population and industrialization at these lower latitudes. The carbon isotopic signature of these emissions has been re-examined. The emissions of the last two decades are approximately 1{per_thousand} lighter than previously reported (Tans, 1981). This lightening of the emissions signature is due to fossil fuel gases and liquids, including a revision of their {delta}{sup 13}C isotopic signature and an increased production rate.

  3. Fast analysis of carbon content by inelastic scattering of neutrons

    International Nuclear Information System (INIS)

    Heinrich, B.; Irmer, K.; Poetschke, R.

    1986-01-01

    The direct measurement of carbon concentration of conveyor belts is a difficult problem. The great penetration depth by the fast neutrons and the 4.43 MeV γ-radiation gives an especially suitable method. The measurement were performed by the following methods: excitation of γ-radiation by a Pu-Be neutron source, excitation of γ-radiation by DT-neutron generator in stationary regime, in pulse regime, or coupled with time correlated associated particle method. Furthermore, a special Monte Carlo code in which the geometry of the measuring equipment could be specified, was written to calculate the 4.43 MeV γ counting rate for backscatter geometries and for penetration geometries. The influence of conveyor belt, of content of H, O, Fe and of mass by surface for 4.43 MeV γ-radiation was calculated for application brown coal in industry. (author)

  4. Investigate of analysis for hydrogen contents in carbon films

    International Nuclear Information System (INIS)

    Yasui, Haruyuki; Hirose, Yukio; Sasaki, Toshihiko; Awazu, Kaoru; Naramoto, Hiroshi

    2001-01-01

    Hydrogen is a very common contaminant in carbon films. It can strongly influences on mechanical, physical and chemical properties of the films. The analysis of hydrogen is therefore a crucial problem to prepare the films with the reproducible property. We were measured two kinds of methods. Ion beam techniques using nuclear reactions are established methods for the quantitative determination of hydrogen concentration. A spectrometer has been constructed for the determination of hydrogen concentrations by detecting 4.43 MeV γ-rays from the resonant nuclear reactions 1 H( 15 N, α γ) 12 C at the 6.385 MeV. And the other measurement of hydrogen is GDOES (Glow Discharge Optical Emission Spectroscopy), with its high sputtering rates, had been used previously for depth profiling analysis of thin films. The depth profiling analysis was carried out at an argon atmosphere by applying an RF of 13.56 MHz. The sampling time interval was 0.1 sec. The detailed hydrogen analysis was made on BCN (Boron Carbonitride) and DLC (Diamond-like Carbon) thin films. The BCN films were prepared by ion beam assisted deposition, in which boron and carbon were deposited by electron beam heating of B 4 C solid and nitrogen was supplied by implantation simultaneously. The DLC films were prepared by HPPC (Hybrid-pulse plasma coating) system. It was a new coating system that we developed which consists fundamentally of plasma CVD (chemical vapor deposition) and ion-mixing. In this paper, we reported the comparison of analysis for hydrogen contents between RNRA and GDOES. (author)

  5. Investigate of analysis for hydrogen contents in carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, Haruyuki; Hirose, Yukio; Sasaki, Toshihiko [Kanazawa Univ., Kanazawa, Ishikawa (Japan); Awazu, Kaoru [Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa (Japan); Naramoto, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-07-01

    Hydrogen is a very common contaminant in carbon films. It can strongly influences on mechanical, physical and chemical properties of the films. The analysis of hydrogen is therefore a crucial problem to prepare the films with the reproducible property. We were measured two kinds of methods. Ion beam techniques using nuclear reactions are established methods for the quantitative determination of hydrogen concentration. A spectrometer has been constructed for the determination of hydrogen concentrations by detecting 4.43 MeV {gamma}-rays from the resonant nuclear reactions {sup 1}H({sup 15}N, {alpha} {gamma}){sup 12}C at the 6.385 MeV. And the other measurement of hydrogen is GDOES (Glow Discharge Optical Emission Spectroscopy), with its high sputtering rates, had been used previously for depth profiling analysis of thin films. The depth profiling analysis was carried out at an argon atmosphere by applying an RF of 13.56 MHz. The sampling time interval was 0.1 sec. The detailed hydrogen analysis was made on BCN (Boron Carbonitride) and DLC (Diamond-like Carbon) thin films. The BCN films were prepared by ion beam assisted deposition, in which boron and carbon were deposited by electron beam heating of B{sub 4}C solid and nitrogen was supplied by implantation simultaneously. The DLC films were prepared by HPPC (Hybrid-pulse plasma coating) system. It was a new coating system that we developed which consists fundamentally of plasma CVD (chemical vapor deposition) and ion-mixing. In this paper, we reported the comparison of analysis for hydrogen contents between RNRA and GDOES. (author)

  6. Digital Mapping of Soil Organic Carbon Contents and Stocks in Denmark

    DEFF Research Database (Denmark)

    Adhikari, Kabindra; Hartemink, Alfred E.; Minasny, Budiman

    2014-01-01

    Estimation of carbon contents and stocks are important for carbon sequestration, greenhouse gas emissions and national carbon balance inventories. For Denmark, we modeled the vertical distribution of soil organic carbon (SOC) and bulk density, and mapped its spatial distribution at five standard ...

  7. Fossil energy consumption and greenhouse gas emissions, including soil carbon effects, of producing agriculture and forestry feedstocks

    Science.gov (United States)

    Christina E. Canter; Zhangcai Qin; Hao Cai; Jennifer B. Dunn; Michael Wang; D. Andrew Scott

    2017-01-01

    The GHG emissions and fossil energy consumption associated with producing potential biomass sup­ply in the select BT16 scenarios include emissions and energy consumption from biomass production, harvest/collection, transport, and pre-processing activities to the reactor throat. Emissions associated with energy, fertilizers, and...

  8. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

    Science.gov (United States)

    Talhelm, Alan F; Pregitzer, Kurt S; Kubiske, Mark E; Zak, Donald R; Campany, Courtney E; Burton, Andrew J; Dickson, Richard E; Hendrey, George R; Isebrands, J G; Lewin, Keith F; Nagy, John; Karnosky, David F

    2014-01-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and tropospheric ozone (O3) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3. Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r2 = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m−2) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (ΔNPP/ΔN) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2. Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content. PMID:24604779

  9. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests.

    Science.gov (United States)

    Talhelm, Alan F; Pregitzer, Kurt S; Kubiske, Mark E; Zak, Donald R; Campany, Courtney E; Burton, Andrew J; Dickson, Richard E; Hendrey, George R; Isebrands, J G; Lewin, Keith F; Nagy, John; Karnosky, David F

    2014-08-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2 ) and tropospheric ozone (O3 ) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3 . Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r(2) = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m(-2) ) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (∆NPP/∆N) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2 . Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content. © 2014 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

  10. Fossil-Fuel C02 Emissions Database and Exploration System

    Science.gov (United States)

    Krassovski, M.; Boden, T.

    2012-04-01

    Fossil-Fuel C02 Emissions Database and Exploration System Misha Krassovski and Tom Boden Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory The Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL) quantifies the release of carbon from fossil-fuel use and cement production each year at global, regional, and national spatial scales. These estimates are vital to climate change research given the strong evidence suggesting fossil-fuel emissions are responsible for unprecedented levels of carbon dioxide (CO2) in the atmosphere. The CDIAC fossil-fuel emissions time series are based largely on annual energy statistics published for all nations by the United Nations (UN). Publications containing historical energy statistics make it possible to estimate fossil-fuel CO2 emissions back to 1751 before the Industrial Revolution. From these core fossil-fuel CO2 emission time series, CDIAC has developed a number of additional data products to satisfy modeling needs and to address other questions aimed at improving our understanding of the global carbon cycle budget. For example, CDIAC also produces a time series of gridded fossil-fuel CO2 emission estimates and isotopic (e.g., C13) emissions estimates. The gridded data are generated using the methodology described in Andres et al. (2011) and provide monthly and annual estimates for 1751-2008 at 1° latitude by 1° longitude resolution. These gridded emission estimates are being used in the latest IPCC Scientific Assessment (AR4). Isotopic estimates are possible thanks to detailed information for individual nations regarding the carbon content of select fuels (e.g., the carbon signature of natural gas from Russia). CDIAC has recently developed a relational database to house these baseline emissions estimates and associated derived products and a web-based interface to help users worldwide query these data holdings. Users can identify, explore and download desired CDIAC

  11. Carbon dioxide emissions from fossil fuel consumption and cement manufacture, 1751-1991, and an estimate of their isotopic composition and latitudinal distribution

    Energy Technology Data Exchange (ETDEWEB)

    Andres, R.J.; Marland, G.; Boden, T.; Bischof, S. [University of Alaska, Fairbanks, AK (USA). Inst. of Northern Engineering

    2000-05-01

    This work briefly discusses four of the current research emphases at Oak Ridge National Laboratory regarding the emission of CO{sub 2} from fossil fuel consumption, natural gas flaring, and cement manufacture. These emphases include: (1) updating the 1950 to present time series of CO{sub 2} emissions from fossil fuel consumption and cement manufacture, (2) extending this time series back to 1751, (3) gridding the data at 1 x 1{degree} resolution, and (4) estimating the isotopic signature of these emissions. A latitudinal distribution of carbon emissions is being completed. A southward shift in the major mass of CO{sub 2} emissions is occurring from European-North American latitudes toward Central-Southeast Asian latitudes, reflecting the growth of population and industrialization at these lower latitudes. The carbon isotopic signature of these CO{sub 2} emissions has been reexamined. The emissions of the past two decades were approximately 1% lighter than previously estimated. 37 refs., 5 figs., 5 tabs.

  12. Texture and organic carbon contents do not impact amount of carbon protected in Malagasy soils

    Directory of Open Access Journals (Sweden)

    Tantely Razafimbelo

    2013-06-01

    Full Text Available Soil organic carbon (SOC is usually said to be well correlated with soil texture and soil aggregation. These relations generally suggest a physical and physicochemical protection of SOC within soil aggregates and on soil fine particles, respectively. Because there are few experimental evidences of these relations on tropical soils, we tested the relations of soil variables (SOC and soil aggregate contents, and soil texture with the amount of SOC physically protected in aggregates on a set of 15 Malagasy soils. The soil texture, the SOC and water stable macroaggregate (MA contents and the amount of SOC physically protected inside aggregates, calculated as the difference of C mineralized by crushed and intact aggregates, were characterized. The relation between these variables was established. SOC content was significantly correlated with soil texture (clay+fine silt fraction and with soil MA amount while protected SOC content was not correlated with soil MA amount. This lack of correlation might be attributed to the highest importance of physicochemical protection of SOC which is demonstrated by the positive relation between SOC and clay+fine silt fraction.

  13. Distributions of carbon pricing on extraction, combustion and consumption of fossil fuels in the global supply-chain

    Science.gov (United States)

    Karstensen, Jonas; Peters, Glen

    2018-01-01

    Pricing carbon is one of the most important tools to reduce emissions and mitigate climate change. Already, about 40 nations have implemented explicit or implicit carbon prices, and a carbon price was explicitly stated as a mitigation strategy by many nations in their emission pledges submitted to the Paris Agreement. The coverage of carbon prices varies significantly between nations though, often only covering a subset of sectors in the economy. We investigate the propagation of carbon prices along the global supply-chain when the carbon price is applied at the point where carbon is removed from the ground (extraction), is combusted (production), or where goods and services are consumed (consumption). We consider both the regional and sectoral effects, and compare the carbon price income and costs relative to economic output. We find that implementation using different accounting systems makes a significant difference to revenues and increased expenditure, and that domestic and global trade plays a significant role in spreading the carbon price between sectors and countries. A few single sectors experience the largest relative price increases (especially electricity and transport), but most of the carbon price is ultimately paid by households for goods and services due to the large expenditure and indirect supply chain impacts. We finally show that a global carbon price will generate a larger share of revenue relative to GDP in non-OECD nations than OECD nations, independent on the point of implementation.

  14. Relating black carbon content to reduction of snow albedo

    Science.gov (United States)

    Brandt, R. E.; Warren, S. G.; Clarke, A. D.

    2011-12-01

    In remote snow of the Northern Hemisphere, the levels of soot pollution are in the parts-per-billion (ppb) range, where the effect on albedo is at the level of a few percent. A reduction of albedo by 1-2% is significant for climate but is difficult to detect experimentally, because snow albedo depends on several other variables. In our work to quantify the climatic effect of black carbon (BC) in snow, we therefore do not directly measure the albedo reduction. Instead, we use a two-step procedure: (1) We collect snow samples, melt and filter them, and analyze the filters spectrophotometrically for BC concentration. (2) We use the BC amount from the filter measurement, together with snow grain size, in a radiative transfer model to compute the albedo reduction. Our radiative transfer model uses the discrete ordinates algorithm DISORT 2.0. We have chosen a representative BC size distribution and optical constants, and have incorporated those of mineral dust as well. While a given mass of BC causes over an order of magnitude more snow albedo reduction compared to dust, a snowpack containing dust mutes the albedo-reducing effect of BC. Because the computed reduction of snow albedo is model-based, it requires experimental verification. We doubt that direct measurement of albedo-reduction will be feasible in nature, because of the vertical variation of both snow grain size and soot content, and because the natural soot content is small. We conclude that what is needed is an artificial snowpack, with uniform grain size and large uniform soot content (ppm not ppb), to produce a large signal on albedo. We have chosen to pursue this experiment outdoors rather than in the laboratory, for the following reasons: (1) The snowpack in the field of view is uniformly illuminated if the source of radiation is the Sun. (2) Visible radiation penetrates into the snow, so photons emerge horizontally distant from where they entered. In the limited width of a laboratory snowpack, radiation

  15. Interfaces between Model Co-W-C Alloys with Various Carbon Contents and Tungsten Carbide

    Directory of Open Access Journals (Sweden)

    Igor Konyashin

    2018-03-01

    Full Text Available Interfaces between alloys simulating binders in WC-Co cemented carbides and tungsten carbide were examined on the micro-, nano-, and atomic-scale. The precipitation of fine WC grains and η-phase occurs at the interface of the alloy with the low carbon content. The precipitation of such grains almost does not occur in the alloy with the medium-low carbon content and does not take place in the alloy with the high carbon content. The formation of Co nanoparticles in the binder alloy with the medium-low carbon content was established. Interfaces in the alloy with the medium-low carbon content characterized by complete wetting with respect to WC and with the high carbon content characterized by incomplete wetting were examined at an atomic scale. The absence of any additional phases or carbon segregations at both of the interfaces was established. Thus, the phenomenon of incomplete wetting of WC by liquid binders with high carbon contents is presumably related to special features of the Co-based binder alloys oversaturated with carbon at sintering temperatures.

  16. Organic carbon, nitrogen and phosphorus contents of some soils of kaliti tea-estate, Bangladesh

    International Nuclear Information System (INIS)

    Ahmed, M. S.; Shahin, M. M. H.; Sanaullah, A. F. M.

    2005-01-01

    Some soil samples were collected from Kaliti Tea-Estate of Moulvibazar district, Bangladesh. Total nitrogen, organic carbon, organic matter, carbon-nitrogen ratio and available phosphorus content of the collected soil samples of different depths and of different topographic positions have been determined. Total nitrogen was found 0.07 to 0.12 % organic carbon and organic matter content found to vary from 0.79 to 1.25 and 1.36 to 2.15 % respectively. Carbon-nitrogen ratio of these soils varied from 9.84 to 10.69, while available phosphorus content varied from 2.11 to 4.13 ppm. (author)

  17. Inferring absorbing organic carbon content from AERONET data

    Directory of Open Access Journals (Sweden)

    A. Arola

    2011-01-01

    Full Text Available Black carbon, light-absorbing organic carbon (often called "brown carbon" and mineral dust are the major light-absorbing aerosols. Currently the sources and formation of brown carbon aerosol in particular are not well understood. In this study we estimated the amount of light–absorbing organic carbon and black carbon from AERONET measurements. We find that the columnar absorbing organic carbon (brown carbon levels in biomass burning regions of South America and Africa are relatively high (about 15–20 mg m−2 during biomass burning season, while the concentrations are significantly lower in urban areas in US and Europe. However, we estimated significant absorbing organic carbon amounts from the data of megacities of newly industrialized countries, particularly in India and China, showing also clear seasonality with peak values up to 30–35 mg m−2 during the coldest season, likely caused by the coal and biofuel burning used for heating. We also compared our retrievals with the modeled organic carbon by the global Oslo CTM for several sites. Model values are higher in biomass burning regions than AERONET-based retrievals, while the opposite is true in urban areas in India and China.

  18. Inferring absorbing organic carbon content from AERONET data

    Science.gov (United States)

    Arola, A.; Schuster, G.; Myhre, G.; Kazadzis, S.; Dey, S.; Tripathi, S. N.

    2011-01-01

    Black carbon, light-absorbing organic carbon (often called "brown carbon") and mineral dust are the major light-absorbing aerosols. Currently the sources and formation of brown carbon aerosol in particular are not well understood. In this study we estimated the amount of light-absorbing organic carbon and black carbon from AERONET measurements. We find that the columnar absorbing organic carbon (brown carbon) levels in biomass burning regions of South America and Africa are relatively high (about 15-20 mg m-2 during biomass burning season), while the concentrations are significantly lower in urban areas in US and Europe. However, we estimated significant absorbing organic carbon amounts from the data of megacities of newly industrialized countries, particularly in India and China, showing also clear seasonality with peak values up to 30-35 mg m-2 during the coldest season, likely caused by the coal and biofuel burning used for heating. We also compared our retrievals with the modeled organic carbon by the global Oslo CTM for several sites. Model values are higher in biomass burning regions than AERONET-based retrievals, while the opposite is true in urban areas in India and China.

  19. Investigation of black and brown carbon multiple-wavelength-dependent light absorption from biomass and fossil fuel combustion source emissions

    Science.gov (United States)

    Michael R. Olson; Mercedes Victoria Garcia; Michael A. Robinson; Paul Van Rooy; Mark A. Dietenberger; Michael Bergin; James Jay Schauer

    2015-01-01

    Quantification of the black carbon (BC) and brown carbon (BrC) components of source emissions is critical to understanding the impact combustion aerosols have on atmospheric light absorption. Multiple-wavelength absorption was measured from fuels including wood, agricultural biomass, coals, plant matter, and petroleum distillates in controlled combustion settings....

  20. Determination of Hydrogen and Carbon contents in crude oil and Petroleum fractions by NMR Spectroscopy

    International Nuclear Information System (INIS)

    Khadim, Mohammad A.; Wolny, R.A.; Al-Dhuwaihi, Abdullah S.; Al-Hajri, E.A.; Al-Ghamdi, M.A.

    2003-01-01

    Proton and carbon-13 NMR spectroscopic methods were developed for determining hydrogen and carbon contents in petroleum products. These methods are applicable to a wide of petroleum streams. A new reference standard, bis (trimethylsilyl) methane, BTMSM, is introduced fro both proton and carbon-13 NMR for the first time, which offers several advantages over those customarily employed. These methods are important for the calculation of the mass balance and hydrogen consumption in pilot plant studies. Unlike the ASTM D-5291 combustion method, the NMR methods also allow for the measurement of hydrogen and carbon content in low boiling fractions and those containing hydrogen as low as 1%. The NMR methods can also determine aromatic and aliphatic hydrogens carbons in a given sample without additional experimentation. The precision and accuracy of the newly developed NMR methods are compared with those of currently employed ASTM D-5291 combustion method. Using the proton NMR method, hydrogen content was determined in fifteen model compounds and sixty-eight petroleum fractions. The NMR and ASTM methods show an agreement within +5%for 48 out of a total number of 68 oil fractions. Using carbon-13 NMR, the carbon content was determined for four representative compounds and three fractions of crude oil. Both carbon-13 NMR and ASTM methods give comparable carbon content in model compounds and crude oil fractions. (author)

  1. A multiresolution spatial parametrization for the estimation of fossil-fuel carbon dioxide emissions via atmospheric inversions.

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Jaideep; Lee, Jina; Lefantzi, Sophia; Yadav, Vineet [Carnegie Institution for Science, Stanford, CA; Michalak, Anna M. [Carnegie Institution for Science, Stanford, CA; van Bloemen Waanders, Bart Gustaaf [Sandia National Laboratories, Albuquerque, NM; McKenna, Sean Andrew [IBM Research, Mulhuddart, Dublin 15, Ireland

    2013-04-01

    The estimation of fossil-fuel CO2 emissions (ffCO2) from limited ground-based and satellite measurements of CO2 concentrations will form a key component of the monitoring of treaties aimed at the abatement of greenhouse gas emissions. To that end, we construct a multiresolution spatial parametrization for fossil-fuel CO2 emissions (ffCO2), to be used in atmospheric inversions. Such a parametrization does not currently exist. The parametrization uses wavelets to accurately capture the multiscale, nonstationary nature of ffCO2 emissions and employs proxies of human habitation, e.g., images of lights at night and maps of built-up areas to reduce the dimensionality of the multiresolution parametrization. The parametrization is used in a synthetic data inversion to test its suitability for use in atmospheric inverse problem. This linear inverse problem is predicated on observations of ffCO2 concentrations collected at measurement towers. We adapt a convex optimization technique, commonly used in the reconstruction of compressively sensed images, to perform sparse reconstruction of the time-variant ffCO2 emission field. We also borrow concepts from compressive sensing to impose boundary conditions i.e., to limit ffCO2 emissions within an irregularly shaped region (the United States, in our case). We find that the optimization algorithm performs a data-driven sparsification of the spatial parametrization and retains only of those wavelets whose weights could be estimated from the observations. Further, our method for the imposition of boundary conditions leads to a 10computational saving over conventional means of doing so. We conclude with a discussion of the accuracy of the estimated emissions and the suitability of the spatial parametrization for use in inverse problems with a significant degree of regularization.

  2. Analysis of Seasonal Soil Organic Carbon Content at Bukit Jeriau Forest, Fraser Hill, Pahang

    International Nuclear Information System (INIS)

    Ahmad Adnan Mohamed; Ahmad Adnan Mohamed; Sahibin Abd Rahim; David Allan Aitman; Mohd Khairul Amri Kamarudin; Mohd Khairul Amri Kamarudin

    2016-01-01

    Soil carbon is the carbon held within the soil, primarily in association with its organic content. The total soil organic carbon study was determined in a plot at Bukit Jeriau forest in Bukit Fraser, Pahang, Malaysia. The aim of this study is to determine the changing of soil organic carbon between wet season and dry season. Soil organic carbon was fined out using titrimetric determination. The soil organic carbon content in wet season is 223.24 t/ ha while dry season is 217.90 t/ ha. The soil pH range in wet season is between 4.32 to 4.45 and in dry season in 3.95 to 4.08 which is considered acidic. Correlation analysis showed that soil organic carbon value is influenced by pH value and climate. Correlation analysis between clay and soil organic carbon with depth showed positively significant differences and clay are very much influenced soil organic carbon content. Correlation analysis between electrical conductivity and soil organic carbon content showed negative significantly difference on wet season and positively significant different in dry season. (author)

  3. Long time management of fossil fuel resources to limit global warming and avoid ice age onsets

    Science.gov (United States)

    Shaffer, Gary

    2009-02-01

    There are about 5000 billion tons of fossil fuel carbon in accessible reserves. Combustion of all this carbon within the next few centuries would force high atmospheric CO2 content and extreme global warming. On the other hand, low atmospheric CO2 content favors the onset of an ice age when changes in the Earth's orbit lead to low summer insolation at high northern latitudes. Here I present Earth System Model projections showing that typical reduction targets for fossil fuel use in the present century could limit ongoing global warming to less than one degree Celcius above present. Furthermore, the projections show that combustion pulses of remaining fossil fuel reserves could then be tailored to raise atmospheric CO2 content high and long enough to parry forcing of ice age onsets by summer insolation minima far into the future. Our present interglacial period could be extended by about 500,000 years in this way.

  4. Towards space based verification of CO2 emissions from strong localized sources: fossil fuel power plant emissions as seen by a CarbonSat constellation

    Directory of Open Access Journals (Sweden)

    T. Krings

    2011-12-01

    Full Text Available Carbon dioxide (CO2 is the most important man-made greenhouse gas (GHG that cause global warming. With electricity generation through fossil-fuel power plants now being the economic sector with the largest source of CO2, power plant emissions monitoring has become more important than ever in the fight against global warming. In a previous study done by Bovensmann et al. (2010, random and systematic errors of power plant CO2 emissions have been quantified using a single overpass from a proposed CarbonSat instrument. In this study, we quantify errors of power plant annual emission estimates from a hypothetical CarbonSat and constellations of several CarbonSats while taking into account that power plant CO2 emissions are time-dependent. Our focus is on estimating systematic errors arising from the sparse temporal sampling as well as random errors that are primarily dependent on wind speeds. We used hourly emissions data from the US Environmental Protection Agency (EPA combined with assimilated and re-analyzed meteorological fields from the National Centers of Environmental Prediction (NCEP. CarbonSat orbits were simulated as a sun-synchronous low-earth orbiting satellite (LEO with an 828-km orbit height, local time ascending node (LTAN of 13:30 (01:30 p.m. LT and achieves global coverage after 5 days. We show, that despite the variability of the power plant emissions and the limited satellite overpasses, one CarbonSat has the potential to verify reported US annual CO2 emissions from large power plants (≥5 Mt CO2 yr−1 with a systematic error of less than ~4.9% and a random error of less than ~6.7% for 50% of all the power plants. For 90% of all the power plants, the systematic error was less than ~12.4% and the random error was less than ~13%. We additionally investigated two different satellite configurations using a combination of 5 CarbonSats. One achieves global coverage everyday but only samples the targets at fixed local times. The other

  5. Electricity from fossil fuels without CO2 emissions: assessing the costs of carbon dioxide capture and sequestration in U.S. electricity markets.

    Science.gov (United States)

    Johnson, T L; Keith, D W

    2001-10-01

    The decoupling of fossil-fueled electricity production from atmospheric CO2 emissions via CO2 capture and sequestration (CCS) is increasingly regarded as an important means of mitigating climate change at a reasonable cost. Engineering analyses of CO2 mitigation typically compare the cost of electricity for a base generation technology to that for a similar plant with CO2 capture and then compute the carbon emissions mitigated per unit of cost. It can be hard to interpret mitigation cost estimates from this plant-level approach when a consistent base technology cannot be identified. In addition, neither engineering analyses nor general equilibrium models can capture the economics of plant dispatch. A realistic assessment of the costs of carbon sequestration as an emissions abatement strategy in the electric sector therefore requires a systems-level analysis. We discuss various frameworks for computing mitigation costs and introduce a simplified model of electric sector planning. Results from a "bottom-up" engineering-economic analysis for a representative U.S. North American Electric Reliability Council (NERC) region illustrate how the penetration of CCS technologies and the dispatch of generating units vary with the price of carbon emissions and thereby determine the relationship between mitigation cost and emissions reduction.

  6. Earth 2075 (CO2) - can Ocean-Amplified Carbon Capture (oacc) Impart Atmospheric CO2-SINKING Ability to CCS Fossil Energy?

    Science.gov (United States)

    Fry, R.; Routh, M.; Chaudhuri, S.; Fry, S.; Ison, M.; Hughes, S.; Komor, C.; Klabunde, K.; Sethi, V.; Collins, D.; Polkinghorn, W.; Wroobel, B.; Hughes, J.; Gower, G.; Shkolnik, J.

    2017-12-01

    Previous attempts to capture atmospheric CO2 by algal blooming were stalled by ocean viruses, zooplankton feeding, and/or bacterial decomposition of surface blooms, re-releasing captured CO2 instead of exporting it to seafloor. CCS fossil energy coupling could bypass algal bloom limits—enabling capture of 10 GtC/yr atmospheric CO2 by selective emiliania huxleyi (EHUX) blooming in mid-latitude open oceans, far from coastal waters and polar seas. This could enable a 500 GtC drawdown, 350 ppm restoration by 2050, 280 ppm CO2 by 2075, and ocean pH 8.2. White EHUX blooms could also reflect sunlight back into outer space and seed extra ocean cloud cover, via DMS release, to raise albedo 1.8%—restoring preindustrial temperature (ΔT = 0°C) by 2030. Open oceans would avoid post-bloom anoxia, exclusively a coastal water phenomenon. The EHUX calcification reaction initially sources CO2, but net sinking prevails in follow-up equilibration reactions. Heavier-than-water EHUX sink captured CO2 to the sea floor before surface decomposition occurs. Seeding EHUX high on their nonlinear growth curve could accelerate short-cycle secondary open-ocean blooming—overwhelming mid-latitude viruses, zooplankton, and competition from other algae. Mid-latitude "ocean deserts" exhibit low viral, zooplankton, and bacterial counts. Thermocline prevents nutrient upwelling that would otherwise promote competing algae. Adding nitrogen nutrient would foster exclusive EHUX blooming. Elevated EHUX seed levels could arise from sealed, pH-buffered, floating, seed-production bioreactors infused with 10% CO2 from carbon feedstock supplied by inland CCS fossil power plants capturing 90% of emissions as liquid CO2. Deep-water SPAR platforms extract natural gas from beneath the sea floor. On-platform Haber and pH processing could convert extracted CH4 to buffered NH4+ nutrient, enabling ≥0.7 GtC/yr of bioreactor seed production and 10 GtC/yr of amplified secondary open-ocean CO2 capture—making CCS

  7. The legacy of fossil fuels.

    Science.gov (United States)

    Armaroli, Nicola; Balzani, Vincenzo

    2011-03-01

    Currently, over 80% of the energy used by mankind comes from fossil fuels. Harnessing coal, oil and gas, the energy resources contained in the store of our spaceship, Earth, has prompted a dramatic expansion in energy use and a substantial improvement in the quality of life of billions of individuals in some regions of the world. Powering our civilization with fossil fuels has been very convenient, but now we know that it entails severe consequences. We treat fossil fuels as a resource that anyone anywhere can extract and use in any fashion, and Earth's atmosphere, soil and oceans as a dump for their waste products, including more than 30 Gt/y of carbon dioxide. At present, environmental legacy rather than consistence of exploitable reserves, is the most dramatic problem posed by the relentless increase of fossil fuel global demand. Harmful effects on the environment and human health, usually not incorporated into the pricing of fossil fuels, include immediate and short-term impacts related to their discovery, extraction, transportation, distribution, and burning as well as climate change that are spread over time to future generations or over space to the entire planet. In this essay, several aspects of the fossil fuel legacy are discussed, such as alteration of the carbon cycle, carbon dioxide rise and its measurement, greenhouse effect, anthropogenic climate change, air pollution and human health, geoengineering proposals, land and water degradation, economic problems, indirect effects on the society, and the urgent need of regulatory efforts and related actions to promote a gradual transition out of the fossil fuel era. While manufacturing sustainable solar fuels appears to be a longer-time perspective, alternatives energy sources already exist that have the potential to replace fossil fuels as feedstocks for electricity production. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The legacy of fossil fuels

    Energy Technology Data Exchange (ETDEWEB)

    Armaroli, N.; Balzani, V. [CNR, Bologna (Italy)

    2011-03-01

    Currently, over 80% of the energy used by mankind comes from fossil fuels. Harnessing coal, oil and gas, the energy resources contained in the store of our spaceship, Earth, has prompted a dramatic expansion in energy use and a substantial improvement in the quality of life of billions of individuals in some regions of the world. Powering our civilization with fossil fuels has been very convenient, but now we know that it entails severe consequences. We treat fossil fuels as a resource that anyone anywhere can extract and use in any fashion, and Earth's atmosphere, soil and oceans as a dump for their waste products, including more than 30 Gt/y of carbon dioxide. At present, environmental legacy rather than consistence of exploitable reserves, is the most dramatic problem posed by the relentless increase of fossil fuel global demand. Harmful effects on the environment and human health, usually not incorporated into the pricing of fossil fuels, include immediate and short-term impacts related to their discovery, extraction, transportation, distribution, and burning as well as climate change that are spread over time to future generations or over space to the entire planet. In this essay, several aspects of the fossil fuel legacy are discussed, such as alteration of the carbon cycle, carbon dioxide rise and its measurement, greenhouse effect, anthropogenic climate change, air pollution and human health, geoengineering proposals, land and water degradation, economic problems, indirect effects on the society, and the urgent need of regulatory efforts and related actions to promote a gradual transition out of the fossil fuel era. While manufacturing sustainable solar fuels appears to be a longer-time perspective, alternatives energy sources already exist that have the potential to replace fossil fuels as feedstocks for electricity production.

  9. Is Time the Best Metric to Measure Carbon-Related Climate Change Potential and Tune the Economy Toward Reduced Fossil Carbon Extraction?

    Science.gov (United States)

    DeGroff, F. A.

    2016-12-01

    Anthropogenic changes to non-anthropogenic carbon fluxes are a primary driver of climate change. There currently exists no comprehensive metric to measure and value anthropogenic changes in carbon flux between all states of carbon. Focusing on atmospheric carbon emissions as a measure of anthropogenic activity on the environment ignores the fungible characteristics of carbon that are crucial in both the biosphere and the worldwide economy. Focusing on a single form of inorganic carbon as a proxy metric for the plethora of anthropogenic activity and carbon compounds will prove inadequate, convoluted, and unmanageable. A broader, more basic metric is needed to capture the entirety of carbon activity, particularly in an economic, profit-driven environment. We propose a new metric to measure changes in the temporal distance of any form or state of carbon from one state to another. Such a metric would be especially useful to measure the temporal distance of carbon from sinks such as the atmosphere or oceans. The effect of changes in carbon flux as a result of any human activity can be measured by the difference between the anthropogenic and non-anthropogenic temporal distance. The change in the temporal distance is a measure of the climate change potential much like voltage is a measure of electrical potential. The integral of the climate change potential is proportional to the anthropogenic climate change. We also propose a logarithmic vector scale for carbon quality, cq, as a measure of anthropogenic changes in carbon flux. The distance between the cq vector starting and ending temporal distances represents the change in cq. A base-10 logarithmic scale would allow the addition and subtraction of exponents to calculate changes in cq. As anthropogenic activity changes the temporal distance of carbon, the change in cq is measured as: cq = ß ( log10 [mean carbon temporal distance] ) where ß represents the carbon price coefficient for a particular country. For any

  10. Thallium and its contents in Remata carbonate rocks

    Directory of Open Access Journals (Sweden)

    Kondelová Marcela

    1996-09-01

    Full Text Available The article presents at first the list of thallium own minerals and its isomorphic content in other minerals, especially in Slovakian ore deposits. This trace element was found in numerous dolomite-rock samples from Remata massif near Handlová. An interesting level of Tl content was analyzed in nonsilicified rocks; the highest content of Tl (and Ag are along the E – W line of disturbance. The presence of thallium in some limonitic aggregates in close Kremnica-gold deposit indicate any continuous relation. Some similarities to type gold deposits Carlin ( USA are discussed, even if no gold and discrete thallium phases were in Remata determined yet.

  11. Size and Carbon Content of Sub-seafloor Microbial Cells at Landsort Deep, Baltic Sea

    DEFF Research Database (Denmark)

    Braun, Stefan; Morono, Yuki; Littmann, Sten

    2016-01-01

    determined the volume and the carbon content of microbial cells from a marine sediment drill core retrieved by the Integrated Ocean Drilling Program (IODP), Expedition 347, at Landsort Deep, Baltic Sea. To determine their shape and volume, cells were separated from the sediment matrix by multi-layer density......-specific carbon content was 19–31 fg C cell−1, which is at the lower end of previous estimates that were used for global estimates of microbial biomass. The cell-specific carbon density increased with sediment depth from about 200 to 1000 fg C μm−3, suggesting that cells decrease their water content and grow...... small cell sizes as adaptation to the long-term subsistence at very low energy availability in the deep biosphere. We present for the first time depth-related data on the cell volume and carbon content of sedimentary microbial cells buried down to 60 m below the seafloor. Our data enable estimates...

  12. Fossil fuel savings, carbon emission reduction and economic attractiveness of medium-scale integrated biomass gasification combined cycle cogeneration plants

    Directory of Open Access Journals (Sweden)

    Kalina Jacek

    2012-01-01

    Full Text Available The paper theoretically investigates the system made up of fluidized bed gasifier, SGT-100 gas turbine and bottoming steam cycle. Different configurations of the combined cycle plant are examined. A comparison is made between systems with producer gas (PG and natural gas (NG fired turbine. Supplementary firing of the PG in a heat recovery steam generator is also taken into account. The performance of the gas turbine is investigated using in-house built Engineering Equation Solver model. Steam cycle is modeled using GateCycleTM simulation software. The results are compared in terms of electric energy generation efficiency, CO2 emission and fossil fuel energy savings. Finally there is performed an economic analysis of a sample project. The results show relatively good performance in the both alternative configurations at different rates of supplementary firing. Furthermore, positive values of economic indices were obtained. [Acknowledgements. This work was carried out within the frame of research project no. N N513 004036, titled: Analysis and optimization of distributed energy conversion plants integrated with gasification of biomass. The project is financed by the Polish Ministry of Science.

  13. Estimates of carbon dioxide emissions from fossil fuels combustion in the main sectors of selected countries 1971-1990

    International Nuclear Information System (INIS)

    Primio, J.C. di.

    1993-01-01

    Calculations of sectoral CO 2 emissions from fossil fuel burning in the period 1971-1990 were done for the 15 countries at the top of the list of nations ordered by decreasing contribution to global emissions, namely: United States of America, Soviet Union, People's Republic of China, Japan, Federal Republic of Germany, United Kingdom, India, Poland, Canada, France, Italy, German Democratic Republic, South Africa, Mexico and Czechoslovakia. In addition, the CO 2 emission of two groups of industrialized countries, namely the OECD and the European Economic Community (EEC) were calculated. The main recommendations of the IPCC/OECD current methodology have been adopted for the calculations, with the principal exception that CO 2 emissions from the use of bunker fuels have not been included in the national estimates. The sectors are: 1. Transformations. Total emissions and the part stemming from power plants 2. Industry (excluding Feedstocks) 3. Transportation 4. Agriculture 5. Residential 6. Commerce and Public Services 7. Non-specified Other 8. Non-Energy Use 9. Feedstocks (in Industry). Data are presented in tables and diagrams. (orig./KW)

  14. Cleaner fossil power generation in the 21st century: a technology strategy for carbon capture and storage

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-04-15

    The document describes how the research, development and demonstration (RD&D) components of the United Kingdom Government's Carbon Abatement Technologies (CATs) Strategy should be developed and extended, with particular reference to a 2020 target for carbon dioxide capture and storage (CCS) commercialisation and the 2050 UK Committee on Climate Change (CCC) dioxide target. It sets out a strategy for RD&D through the establishment of a collaborative programme linking industry, and academia, and involving different funding sources. The proposed RD& D programme has seven strategic themes: Power plant: focus on cost, increasing efficiency, biomass co-firing; Capture technologies: focus on cost, efficiency penalty, waste heat utilisation; storage: focus on security, monitoring and verification; transport: focus on logistics and transport network; whole system: focus on risks, transient capability, economics, environmental issues; advanced and novel capture technologies; and underpinning technology support. 11 refs., 10 figs., 15 tabs.

  15. Reconstructing Middle Eocene Climate and Atmospheric Carbon Dioxide Concentration: Application of a mechanistic theoretical approach to fossil plants from the Messel Pit (Germany)

    Science.gov (United States)

    Grein, M.; Roth-Nebelsick, A.; Wilde, V.; Konrad, W.; Utescher, T.

    2009-12-01

    It is assumed that changes in atmospheric CO2 concentrations (from now on expressed as Ca) strongly influenced the development of global temperatures during parts of the Cenozoic. Thus, detailed knowledge of ancient Ca and its variations is of utmost importance for exploring the coupling of atmospheric CO2 and global climate change. Numerous techniques (such as carbon and boron isotopes) were applied in order to obtain Ca, with varying and sometimes even conflicting results. Stomatal density (number of stomata per leaf area) represents another promising proxy for the calculation of ancient Ca since many plants reduce the number of stomata (pores on the leaf surface used for gas exchange) under increasing Ca. As a reason it is assumed that plants try to adjust stomatal conductance in order to optimize their gas exchange (which means maximal assimilation at minimal transpiration). The common technique for calculating Ca from fossil stomatal frequency is to create empirical transfer functions of living plants derived from herbar material or greenhouse experiments. In the presented project, Ca of the Middle Eocene is calculated by applying a different approach which utilizes a mechanistic-theoretical calibration. It couples the processes of a) C3-photosynthesis, b) diffusion and c) transpiration with palaeoclimatic and leaf-anatomical data. The model also includes an optimisation principle supported by ecophysiological data. According to this optimisation principle, plants adjust their stomatal conductance in such a way that photosynthesis rates are constrained by optimal water use (transpiration). This model was applied in the present study to fossil plants from the Messel Pit near Darmstadt (Germany). In order to reconstruct Ca by using fossil plant taxa from Messel, numerous parameters which represent model input have to be estimated from measurements of living representatives. Furthermore, since climate parameters are also required by the model, quantitative

  16. Remote Sensing of Vegetation Nitrogen Content for Spatially Explicit Carbon and Water Cycle Estimation

    Science.gov (United States)

    Zhang, Y. L.; Miller, J. R.; Chen, J. M.

    2009-05-01

    Foliage nitrogen concentration is a determinant of photosynthetic capacity of leaves, thereby an important input to ecological models for estimating terrestrial carbon and water budgets. Recently, spectrally continuous airborne hyperspectral remote sensing imagery has proven to be useful for retrieving an important related parameter, total chlorophyll content at both leaf and canopy scales. Thus remote sensing of vegetation biochemical parameters has promising potential for improving the prediction of global carbon and water balance patterns. In this research, we explored the feasibility of estimating leaf nitrogen content using hyperspectral remote sensing data for spatially explicit estimation of carbon and water budgets. Multi-year measurements of leaf biochemical contents of seven major boreal forest species were carried out in northeastern Ontario, Canada. The variation of leaf chlorophyll and nitrogen content in response to various growth conditions, and the relationship between them,were investigated. Despite differences in plant type (deciduous and evergreen), leaf age, stand growth conditions and developmental stages, leaf nitrogen content was strongly correlated with leaf chlorophyll content on a mass basis during the active growing season (r2=0.78). With this general correlation, leaf nitrogen content was estimated from leaf chlorophyll content at an accuracy of RMSE=2.2 mg/g, equivalent to 20.5% of the average measured leaf nitrogen content. Based on this correlation and a hyperspectral remote sensing algorithm for leaf chlorophyll content retrieval, the spatial variation of leaf nitrogen content was inferred from the airborne hyperspectral remote sensing imagery acquired by Compact Airborne Spectrographic Imager (CASI). A process-based ecological model Boreal Ecosystem Productivity Simulator (BEPS) was used for estimating terrestrial carbon and water budgets. In contrast to the scenario with leaf nitrogen content assigned as a constant value without

  17. Microbial biocatalyst developments to upgrade fossil fuels.

    Science.gov (United States)

    Kilbane, John J

    2006-06-01

    Steady increases in the average sulfur content of petroleum and stricter environmental regulations concerning the sulfur content have promoted studies of bioprocessing to upgrade fossil fuels. Bioprocesses can potentially provide a solution to the need for improved and expanded fuel upgrading worldwide, because bioprocesses for fuel upgrading do not require hydrogen and produce far less carbon dioxide than thermochemical processes. Recent advances have demonstrated that biodesulfurization is capable of removing sulfur from hydrotreated diesel to yield a product with an ultra-low sulfur concentration that meets current environmental regulations. However, the technology has not yet progressed beyond laboratory-scale testing, as more efficient biocatalysts are needed. Genetic studies to obtain improved biocatalysts for the selective removal of sulfur and nitrogen from petroleum provide the focus of current research efforts.

  18. Microstructural investigations of 0.2% carbon content steel

    Science.gov (United States)

    Tollabimazraehno, Sajjad; Hingerl, Kurt

    2011-10-01

    The effect of thermal annealing to get different phases on low carbon steel was investigated. Steel sheets (0.2 wt. % C) of 900 μm thickness were heat treated to produce different structures. All the samples have the same starting point, transformation to coarse austenite at 900 degree Celsius. The nano indentation results revealed that samples have different hadness. By making conventional SEM micrographs, focus ion beam maps, and Electron backscatter diffraction (EBSD) the microstructural development and grain boundary variation of transformed phases martensite, biainte, tempered martensite and different combination of these phases were studied.

  19. Properties of welded joints of 2,25Cr-1Mo steel with various carbon content

    International Nuclear Information System (INIS)

    Vornovitskij, I.N.; Brodetskaya, E.Z.; Pozdnyakova, A.S.

    1980-01-01

    Properties of welded joints of 2,25 Cr - 1 Mo steel pipelines with different carbon content are considered. It is shown that application of electrodes developed in some countries for welding permits in many cases to exclude heat treatment of welded joints owing to high ductility of weld deposited metal. To improve the ductility, it is necessary to limit both carbon content down to 0,03-0,06% and detrimental elements (sulfur, phosphorus). Heat affected zone hardness may be increased at the expense of carbon. Weld deposited metal possesses the highest long-term strength at the given test temperature; in this case long-term strength of welded joints and base metal is practically the same. The long-term strength of high-carbon steel is higher at the test temperature of 565 deg C as compared to mean-carbon and low-carbon steels, whose long-term strength is practically equal at this temperature. The long-term strength of high-carbon and mean-carbon steels is practically the same and higher as compared with low-carbon one at the test temperature of 510 deg C

  20. Effect of alkali metal content of carbon on retention of iodine at high temperatures

    International Nuclear Information System (INIS)

    Evans, A.G.

    1975-01-01

    Activated carbon for filters in reactor confinement systems is intentionally impregnated with iodine salts to enhance the removal of radioiodine from air streams containing organic iodides. When a variety of commercial impregnated carbons were evaluated for iodine retention at elevated temperatures (4 hours at 180 0 C), wide variations in iodine penetration were observed. The alkali metal and iodine content of carbon samples was determined by neutron activation analysis, and a strong correlation was shown between the atom ratio of iodine to alkali metals in the carbons and the high-temperature retention performance. Carbons containing excess alkali (especially potassium) have iodine penetration values 10 to 100 times lower than carbons containing excess iodine. Both low I/K ratios and high pH values were shown essential to high efficiency iodine retention; therefore, conversion of elemental iodine to ionic iodine is the basic reaction mechanism. The natural high K + content and high pH coconut carbons make coconut the preferred natural base material for nuclear air cleaning applications. Studies show, however, that treatment of low potassium carbons with a mixture of KOH and I 2 may produce a product equal to or better than I 2 -impregnated coconut carbons at a lower cost. (U.S.)

  1. Physical and chemical protection of soil organic carbon in three agricultural soils with different contents of calcium carbonate

    International Nuclear Information System (INIS)

    Clough, A.; Skjemstad, J.O.

    2000-01-01

    The amount of organic carbon physically protected by entrapment within aggregates and through polyvalent cation organic matter bridging was determined on non-calcareous and calcareous soils. The composition of organic carbon in whole soils and 13 C NMR analysis. High energy photo-oxidation was carried out on <53 μm fractions and results from the NMR spectra showed 17-40% of organic carbon was in a condensed aromatic form, most likely charcoal (char). The concept that organic material remaining after photo-oxidation may be physically protected within aggregates was investigated by treating soils with a mild acid prior to photo-oxidation. More organic material was protected in the calcareous than the non-calcareous soils, regardless of whether the calcium occurred naturally or was an amendment. Acid treatment indicated that the presence of exchangeable calcium reduced losses of organic material upon photo-oxidation by about 7% due to calcium bridging. These results have implications for N fertiliser recommendations based upon organic carbon content. Firstly, calcium does not impact upon degradability of organic material to an extent likely to affect N fertiliser recommendations. Secondly, standard assessment techniques overestimate active organic carbon content in soils with high char content. Copyright (2000) CSIRO Publishing

  2. Relation between PAH and black carbon contents in size fractions of Norwegian harbor sediments

    International Nuclear Information System (INIS)

    Oen, Amy M.P.; Cornelissen, Gerard; Breedveld, Gijs D.

    2006-01-01

    Distributions of total organic carbon (TOC), black carbon (BC), and polycyclic aromatic hydrocarbons (PAH) were investigated in different particle size fractions for four Norwegian harbor sediments. The total PAH (16-EPA) concentrations ranged from 2 to 113 mg/kg dry weight with the greatest fraction of PAH mass in the sand fraction for three of the four sediments. TOC contents ranged from 0.84% to 14.2% and BC contents from 0.085% to 1.7%. This corresponds to organic carbon (OC = TOC - BC) contents in the range of 0.81-14% and BC:TOC ratios of 1.3-18.1%. PAH isomer ratios suggested that the PAH in all four sediments were of pyrogenic origin. Furthermore, stronger correlations between PAH versus BC (r 2 = 0.85) than versus OC (r 2 = 0.15) were found. For all size fractions and bulk sediments, the PAH-to-BC ratios for the total PAHs were on average 6 ± 3 mg PAH/g BC. These results suggest that PAH distributions were dominated by the presence of BC, rather than OC. As sorption to BC is much stronger than sorption to OC, this may result in significantly lower dissolved concentrations of PAH than expected on the basis of organic carbon partitioning alone. - PAH contents correlated better with black carbon than organic carbon for four Norwegian harbor sediments

  3. Estimation of black carbon content for biomass burning aerosols from multi-channel Raman lidar data

    Science.gov (United States)

    Talianu, Camelia; Marmureanu, Luminita; Nicolae, Doina

    2015-04-01

    Biomass burning due to natural processes (forest fires) or anthropical activities (agriculture, thermal power stations, domestic heating) is an important source of aerosols with a high content of carbon components (black carbon and organic carbon). Multi-channel Raman lidars provide information on the spectral dependence of the backscatter and extinction coefficients, embedding information on the black carbon content. Aerosols with a high content of black carbon have large extinction coefficients and small backscatter coefficients (strong absorption), while aerosols with high content of organic carbon have large backscatter coefficients (weak absorption). This paper presents a method based on radiative calculations to estimate the black carbon content of biomass burning aerosols from 3b+2a+1d lidar signals. Data is collected at Magurele, Romania, at the cross-road of air masses coming from Ukraine, Russia and Greece, where burning events are frequent during both cold and hot seasons. Aerosols are transported in the free troposphere, generally in the 2-4 km altitude range, and reaches the lidar location after 2-3 days. Optical data are collected between 2011-2012 by a multi-channel Raman lidar and follows the quality assurance program of EARLINET. Radiative calculations are made with libRadTran, an open source radiative model developed by ESA. Validation of the retrievals is made by comparison to a co-located C-ToF Aerosol Mass Spectrometer. Keywords: Lidar, aerosols, biomass burning, radiative model, black carbon Acknowledgment: This work has been supported by grants of the Romanian National Authority for Scientific Research, Programme for Research- Space Technology and Advanced Research - STAR, project no. 39/2012 - SIAFIM, and by Romanian Partnerships in priority areas PNII implemented with MEN-UEFISCDI support, project no. 309/2014 - MOBBE

  4. Carbon, nitrogen and oxygen isotope fractionation during food cooking: Implications for the interpretation of the fossil human record.

    Science.gov (United States)

    Royer, Aurélien; Daux, Valérie; Fourel, François; Lécuyer, Christophe

    2017-08-01

    Stable isotope data provide insight into the reconstruction of ancient human diet. However, cooking may alter the original stable isotope compositions of food due to losses and modifications of biochemical and water components. To address this issue, carbon, nitrogen and oxygen isotope ratios were measured on meat aliquots sampled from various animals such as pork, beef, duck and chicken, and also from the flesh of fishes such as salmon, European seabass, European pilchard, sole, gilt-head bream, and tuna. For each specimen, three pieces were cooked according to the three most commonly-known cooking practices: boiling, frying and roasting on a barbecue. Our data show that cooking produced isotopic shifts up to 1.8‰, 3.5‰, and 5.2‰ for δ 13 C, δ 15 N, and δ 18 O values, respectively. Such variations between raw and cooked food are much greater than previously estimated in the literature; they are more sensitive to the type of food rather than to the cooking process itself, except in the case of boiling. Reconstructions of paleodietary may thus suffer slight bias in cases of populations with undiversified diets that are restrained toward a specific raw or cooked product, or using a specific cooking mode. In cases of oxygen isotope compositions from skeletal remains (bones, teeth), they not only constitute a valuable proxy for reconstructing past climatic conditions, but they could also be used to improve our knowledge of past human diet. © 2017 Wiley Periodicals, Inc.

  5. Cement content influence in rebar corrosion in carbonated mortars

    Directory of Open Access Journals (Sweden)

    Américo, P. O.

    2003-12-01

    Full Text Available The cement hydration products protect the concrete rebars of the reinforced concrete due to the production of Ca(OH2, NaOH, and KOH that, upon dissolving in the concrete s aqueous phase, generate a pH above 12.5. However, reinforced concrete structures are exposed to pollutant gases, such as, CO2 which upon penetrating the concrete, reacts with the alkaline components, consequently reducing the pH of the aqueous phase causing the loss of passivity by the rebar and as a consequence its corrosion when there is the presence of humidity and oxygen. The objective of the current paper is the analysis of the alkaline reserve influence, measured by the cement content, in the corrosion of rebars employing the polarization resistance technique for determining the corrosion intensity. Results for corrosion intensity of rebars embedded in prismatic mortar test specimens are produced with three cement content levels, with equal water/cement ratio. Cylindrical test specimens were also used for verification of the capillary absorption and the porosity by means of mercury porosymetry The results show that the initiation period is shorter and the corrosion intensity of the rebars is higher when the cement content is lower However, there is also an alteration in the microstructure upon altering the cement content, and far this reason one cannot conclude that the alkaline reserve alone is responsible for these results.

    Los productos de hidratación del cemento protegen las armaduras embebidas en el hormigón debido a la gran cantidad de Ca(OH2, NaOH y KOH disueltos en la fase acuosa del hormigón que proporcionan un pH mayor que 12,5. Sin embargo, las estructuras de hormigón armado están expuestas a los gases contaminantes como el CO2, que al penetrar en el hormigón reacciona con los compuestos alcalinos, se reduce el pH de la fase acuosa y provocan la despasivación de la armadura. Posteriormente, si hay

  6. Can mud (silt and clay) concentration be used to predict soil organic carbon content within seagrass ecosystems?

    KAUST Repository

    Serrano, Oscar; Lavery, P. S.; Duarte, Carlos M.; Kendrick, Gary A.; Calafat, Antoni; York, P.; Steven, Andy; Macreadie, Peter I.

    2016-01-01

    The emerging field of blue carbon science is seeking cost-effective ways to estimate the organic carbon content of soils that are bound by coastal vegetated ecosystems. Organic carbon (C-org) content in terrestrial soils and marine sediments has

  7. Determination of the carbon content of domestic farm produces to estimate offsite C-14 ingestion dose

    International Nuclear Information System (INIS)

    Jung, Y. G.; Kim, M. J.; Lee, G. B.

    2003-01-01

    The carbon content of grains, leafy and root vegetables, and fruits which the Koreans usually eat were calculated to use in the estimation of offsite C-14 ingestion dose. With the data of food intake per day in the Report on 1998 national health and nutrition survey- dietary intake survey, 5 age-group integrate d intake of the 4 farm produce groups were extracted for food items and the amount. Intake percentage in each food group were taken as food weighing factor for the foods. Carbon content was calculated using protein, fat, and carbohydrate content of the foods, and multiplied by the corresponding food weighing factor to derive the content of the food groups. The calculated carbon content of grains, leafy and root vegetables, and fruits were 39.%, 4.2%, 8.0%, and 5.9% respectively. Grains and fruits were not much different from ODCM for carbon content, but vegetables were higher by 0.7%∼4.5%

  8. Monetary assessments of carbon dioxide emissions - Comparison between biofuels and fossil fuels; Monetaera vaerderingar av koldioxidutslaepp - jaemfoerelser mellan biobraenslen och fossila braenslen

    Energy Technology Data Exchange (ETDEWEB)

    Ekstroem, C.; Kierkegaard, G. [Vattenfall Utveckling AB, Stockholm (Sweden)] Borgstroem, T. [Swedpower AB (Sweden)

    1999-10-01

    The Swedish tax and subsidy system results in that municipal heat and combined heat and power often can be produced from biofuels at the same as or at lower costs than from fossil fuels. A considerable part of the Swedish municipal district heat is nowadays produced from biofuels. It has been questioned, whether this is justifiable from a national economic point of view, considering realistic estimates of the possible future costs, caused by increased carbon dioxide emissions, that will be avoided this way. There are however large differences between the monetary assessments of carbon dioxide emissions presented in various studies. According to neoclassic national economy, various energy production options should be valued based on their total costs from a national economic point of view. Such total costs include the production costs (`private costs`) as well as `external costs`, i.e. costs that will be brought down upon other parties than the plant owners and the energy buyers. This study illustrates how such total costs for power and heat production from biofuels relative to from natural gas, oil and coal, would be affected if various monetary assessments of carbon dioxide emissions would be treated as external costs and internalised, i.a. charged upon the production costs. The calculations are made for assumed new production plants. The order of precedence (with respect to the lowest total costs) between the studied fuels is affected in favour of biofuels only for high monetary assessments of carbon dioxide emissions. For heat as well as combined heat and power production, an order of precedence corresponding to the carbon dioxide emissions for the respective fuels, will be achieved only for the highest carbon dioxide monetary assessments based on a low discount rate. For condensing power production, the calculated production costs for biofuels are so high that natural gas will get the lowest total costs for all the studied carbon dioxide monetary assessments

  9. FP corrosion dependence on carbon and chromium content in Fe-Cr steel

    International Nuclear Information System (INIS)

    Sasaki, Koei; Tanigaki, Takanori; Fukumoto, Ken-ichi; Uno, Masayoshi

    2015-01-01

    In an attempt to investigate Cs or Cs-Te corrosion dependence on chromium or carbon content in Fe-Cr steel, cesium and Cs-Te corrosion test were performed to three specimens, Fe-9Cr-0C, Fe-9Cr-0.14C and Fe-13Cr-0.14C, for 100 hours at 973K in simulated high burn-up fuel pin environment. Cesium corrosion depth has no dependence on chromium or carbon content in Fe-Cr steel. Cs-Te corrosion was appeared in only Fe-13Cr-0.14C which has chromium carbides ranged along grain boundary. Appearance of the Cs-Te corrosion was determined by distribution or arrangement of chromium carbides which depends on chromium and carbon content. (author)

  10. Change of deuterium volume content in heavy water during carbon dioxide dissolution in it

    International Nuclear Information System (INIS)

    Efimova, T.I.; Kapitanov, V.F.; Levchenko, G.V.

    1985-01-01

    Carbon dioxide solution density in heavy water at increased temperature and pressure is measured and the influence of carbon dioxide solubility in heavy water on volumetric content of deuterium in it is determined. Investigations were conducted in the temperature range of 303-473 K and pressure range of 3-20 MPa by the autoclave method. Volumetric content of deuterium in heavy water decreases sufficiently with CO 2 dissolved in it in comparison with pure D 2 O under the similar conditions, and this decrease becomes more sufficient with the pressure increase. With the temperature increase the volumetric content of deuterium both for heavy water and for saturated carbon solution in heavy water decreases

  11. Hydrogen production by reforming of fossil and biomass fuels accompanied by carbon dioxide capture process is the energy source for the near future

    International Nuclear Information System (INIS)

    Aboudheir, Ahmed; Idem, Raphael; Tontiwachwuthikul, Paitoon; Wilson, Malcolm; Kambietz, Lionel

    2006-01-01

    Hydrogen has a significant future potential as an alternative energy source for the transportation sector as well as in residential homes and offices, H 2 in fuel cell power systems provides an alternative to direct fossil fuel and biomass combustion based technologies and offer the possibility for a significant reduction in greenhouse gas emission based on improved H 2 yield per unit of fossil fuel and biomass, compatibility with renewable energies and motivation to convert to a H 2 -based energy economy. Several practical techniques for H 2 production to service H 2 refuelling stations as well as homes and offices, all of which need to be located at the end of the energy distribution network, include: (1) the carbon dioxide reforming of natural gas; (2) reforming of gasoline; (3) reforming of crude ethanol. Locating the H 2 production at the end of the energy distribution network solves the well-known problems of metal fatigue and high cost of H 2 compression for long distance transportation if H 2 is produced in a large centralized plant. In addition, the ratification of the Kyoto Protocol and the need to reduce emissions of CO 2 to the atmosphere has prompted the capture and utilization of the CO 2 produced from the reforming process. In this research: (1) new efficient catalysts for each reforming process was developed; (2) a new efficient catalyst for our version of the water gas shift reaction to convert carbon monoxide to carbon dioxide was developed; (3) a new membrane separation process for production of high purity, fuel cell-grade H 2 was designed; (4) a numerical model for optimum process design and optimum utilization of resources both at the laboratory and industrial scales was developed; (5) various processes for CO 2 capture were investigated experimentally in order to achieve a net improvement in the absorption process; (6) the utilization of captured CO 2 for enhanced oil recovery and/or storage in an aging oil field were investigated; (7

  12. SEPARATION OF HYDROGEN AND CARBON DIOXIDE USING A NOVEL MEMBRANE REACTOR IN ADVANCED FOSSIL ENERGY CONVERSION PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Shamsuddin Ilias

    2005-02-03

    Inorganic membrane reactors offer the possibility of combining reaction and separation in a single operation at high temperatures to overcome the equilibrium limitations experienced in conventional reactor configurations. Such attractive features can be advantageously utilized in a number of potential commercial opportunities, which include dehydrogenation, hydrogenation, oxidative dehydrogenation, oxidation and catalytic decomposition reactions. However, to be cost effective, significant technological advances and improvements will be required to solve several key issues which include: (a) permselective thin solid film, (b) thermal, chemical and mechanical stability of the film at high temperatures, and (c) reactor engineering and module development in relation to the development of effective seals at high temperature and high pressure. In this project, we are working on the development and application of palladium and palladium-silver alloy thin-film composite membranes in membrane reactor-separator configuration for simultaneous production and separation of hydrogen and carbon dioxide at high temperature. From our research on Pd-composite membrane, we have demonstrated that the new membrane has significantly higher hydrogen flux with very high perm-selectivity than any of the membranes commercially available. The steam reforming of methane by equilibrium shift in Pd-composite membrane reactor is being studied to demonstrate the potential application of this new development. A two-dimensional, pseudo-homogeneous membrane-reactor model was developed to investigate the steam-methane reforming (SMR) reactions in a Pd-based membrane reactor. Radial diffusion was taken into consideration to account for the concentration gradient in the radial direction due to hydrogen permeation through the membrane. With appropriate reaction rate expressions, a set of partial differential equations was derived using the continuity equation for the reaction system. The equations were

  13. Carbon and nitrogen in Danish forest soils - Contents and distribution determined by soil order

    DEFF Research Database (Denmark)

    Vejre, Henrik; Callesen, Ingeborg; Vesterdal, Lars

    2003-01-01

    ). The average total organic C and N contents were 12.5 and 0.61 kg m(-2) respectively. There were large differences in total C and N among soil orders. Spodosols had the greatest C content (14.6 kg m(-2)), and Alfisols the least (8.8 kg m(-2)), while the N content was highest in Alfisols (0.75 kg m(-2......)) and least in Spodosols (0.51 kg m(-2)). The main contributor to the high C content in Spodosols is the spodic horizons containing illuvial humus, and thick organic horizons. Carbon and N concentrations decreased with soil depth. Soil clay content was negatively correlated to C content and positively...

  14. A reassessment of carbon content in wood: variation within and between 41 North American species

    International Nuclear Information System (INIS)

    Lamlom, S.H.; Savidge, R.A.

    2003-01-01

    At present, 50% (w/w) carbon is widely promulgated as a generic value for wood; however, the literature yields few data and indicates that very little research has actually been done. C contents in heartwood of forty-one softwood and hardwood species were determined. C in kiln-dried hardwood species ranged from 46.2% to 49.97% (w/w), in conifers from 47.21% to 55.2%. The higher C in conifers agrees with their higher lignin content (∼30%, versus ∼20% for hardwoods). Wood-meal samples drilled from discrete early wood and late wood zones of seven of the forty-one species were also investigated. C contents of early woods were invariably higher than those in corresponding late woods, again in agreement with early wood having higher lignin content. Further investigation was made into freshly harvested wood of some species to determine how much volatile C is present, comparing oven-dried wood meal with wood meal dried at ambient temperature over a desiccant. C contents of oven-dried woods were significantly lower, indicating that all past data on C content in oven-dried or kiln-dried woods may be inaccurate in relation to the true C content of forests. We conclude that C content varies substantially among species as well as within individual trees. Clearly, a 50% generic value is an oversimplification of limited application in relation to global warming and the concept of 'carbon credits'. (author)

  15. Variations and determinants of carbon content in plants: a global synthesis

    Science.gov (United States)

    Ma, Suhui; He, Feng; Tian, Di; Zou, Dongting; Yan, Zhengbing; Yang, Yulong; Zhou, Tiancheng; Huang, Kaiyue; Shen, Haihua; Fang, Jingyun

    2018-02-01

    Plant carbon (C) content is one of the most important plant traits and is critical to the assessment of global C cycle and ecological stoichiometry; however, the global variations in plant C content remain poorly understood. In this study, we conducted a global analysis of the plant C content by synthesizing data from 4318 species to document specific values and their variation of the C content across plant organs and life forms. Plant organ C contents ranged from 45.0 % in reproductive organs to 47.9 % in stems at global scales, which were significantly lower than the widely employed canonical value of 50 %. Plant C content in leaves (global mean of 46.9 %) was higher than that in roots (45.6 %). Across life forms, woody plants exhibited higher C content than herbaceous plants. Conifers, relative to broad-leaved woody species, had higher C content in roots, leaves, and stems. Plant C content tended to show a decrease with increasing latitude. The life form explained more variation of the C content than climate. Our findings suggest that specific C content values of different organs and life forms developed in our study should be incorporated into the estimations of regional and global vegetation biomass C stocks.

  16. Variations and determinants of carbon content in plants: a global synthesis

    Directory of Open Access Journals (Sweden)

    S. Ma

    2018-02-01

    Full Text Available Plant carbon (C content is one of the most important plant traits and is critical to the assessment of global C cycle and ecological stoichiometry; however, the global variations in plant C content remain poorly understood. In this study, we conducted a global analysis of the plant C content by synthesizing data from 4318 species to document specific values and their variation of the C content across plant organs and life forms. Plant organ C contents ranged from 45.0 % in reproductive organs to 47.9 % in stems at global scales, which were significantly lower than the widely employed canonical value of 50 %. Plant C content in leaves (global mean of 46.9 % was higher than that in roots (45.6 %. Across life forms, woody plants exhibited higher C content than herbaceous plants. Conifers, relative to broad-leaved woody species, had higher C content in roots, leaves, and stems. Plant C content tended to show a decrease with increasing latitude. The life form explained more variation of the C content than climate. Our findings suggest that specific C content values of different organs and life forms developed in our study should be incorporated into the estimations of regional and global vegetation biomass C stocks.

  17. The effect of carbon content on mechanical properties, failure and corrosion resistance of deposited chromium metal

    Directory of Open Access Journals (Sweden)

    Леонід Кімович Лещинськiй

    2017-06-01

    Full Text Available It has been shown that if choosing a metal composition for surfacing rolls and rollers of continuous casting machines, both the carbon impact on the mechanical and functional properties and the critical values of the chromium concentration, which determine the corrosion resistance of the metal with regard to electrochemical corrosion theory, should be considered as well. The paper studied the effect of chromium and carbon steel the X5-X12 type on the structure, technological strength, mechanical properties, fracturing resistance and corrosion resistance of the weld metal. The composition of chromium tool steels (deposited metal (X5-used for the rolls of hot rolling mills and (X12-used for continuous casting machines rollers correspond to these values. The impact of carbon on the properties of the deposited metal containing chromium was considered by comparing the data for both types of the deposited metal. It was found that for both types of the deposited metal (X5 and X12, the limiting value of the carbon content, providing an optimal combination of strength, ductility, failure resistance is the same. If the carbon content is more than the limiting value – (0,25% the technological strength and failure resistance of the deposited metal significantly reduce. With increasing carbon content from 0,18 to 0,25% the martensite structure has a mixed morphology – lath and plate. The strength and toughness of the deposited metal grow. Of particular interest is simultaneous increase in the specific work of failure resulted from crack inhibition at the boundary with far less solid and more ductile ferrite. As for the 5% chromium metal, the X12 type composition with 0,25% C, is borderline. With a further increase in the carbon content of the metal both ductility and failure resistance sharply decrease and with 0,40% C the growth rate of fatigue crack increases by almost 1,5 times

  18. Contents

    Directory of Open Access Journals (Sweden)

    Editor IJRED

    2012-11-01

    Full Text Available International Journal of Renewable Energy Development www.ijred.com Volume 1             Number 3            October 2012                ISSN 2252- 4940   CONTENTS OF ARTICLES page Design and Economic Analysis of a Photovoltaic System: A Case Study 65-73 C.O.C. Oko , E.O. Diemuodeke, N.F. Omunakwe, and E. Nnamdi     Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review 75-80 W.D.P Rengga , M. Sudibandriyo and M. Nasikin     Process Optimization for Ethyl Ester Production in Fixed Bed Reactor Using Calcium Oxide Impregnated Palm Shell Activated Carbon (CaO/PSAC 81-86 A. Buasri , B. Ksapabutr, M. Panapoy and N. Chaiyut     Wind Resource Assessment in Abadan Airport in Iran 87-97 Mojtaba Nedaei       The Energy Processing by Power Electronics and its Impact on Power Quality 99-105 J. E. Rocha and B. W. D. C. Sanchez       First Aspect of Conventional Power System Assessment for High Wind Power Plants Penetration 107-113 A. Merzic , M. Music, and M. Rascic   Experimental Study on the Production of Karanja Oil Methyl Ester and Its Effect on Diesel Engine 115-122 N. Shrivastava,  , S.N. Varma and M. Pandey  

  19. A research needs assessment for the capture, utilization and disposal of carbon dioxide from fossil fuel-fired power plants. Volume 2, Topical reports: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    This study, identifies and assesses system approaches in order to prioritize research needs for the capture and non-atmospheric sequestering of a significant portion of the carbon dioxide (CO{sub 2}) emitted from fossil fuel-fired electric power plants (US power plants presently produce about 7% of the world`s CO{sub 2} emissions). The study considers capture technologies applicable either to existing plants or to those that optimistically might be demonstrated on a commercial scale over the next twenty years. The research needs that have high priority in establishing the technical, environmental, and economic feasibility of large-scale capture and disposal of CO{sub 2} from electric power plants are:(1) survey and assess the capacity, cost, and location of potential depleted gas and oil wells that are suitable CO{sub 2} repositories (with the cooperation of the oil and gas industry); (2) conduct research on the feasibility of ocean disposal, with objectives of determining the cost, residence time, and environmental effects for different methods of CO{sub 2} injection; (3) perform an in-depth survey of knowledge concerning the feasibility of using deep, confined aquifers for disposal and, if feasible, identify potential disposal locations (with the cooperation of the oil and gas industry); (4) evaluate, on a common basis, system and design alternatives for integration of CO{sub 2} capture systems with emerging and advanced technologies for power generation; and prepare a conceptual design, an analysis of barrier issues, and a preliminary cost estimate for pipeline networks necessary to transport a significant portion of the CO{sub 2} to potentially feasible disposal locations.

  20. Organic carbon content of zooplankton from the nearshore waters of Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Gajbhiye, S.N.; Sayed, F.Y.

    Organic carbon content of zooplankton in the Versova Creek and Thana Creek (polluted areas), off Versova and off Mahim, Bombay, India (relatively unpolluted areas) varied respectively from 21.4-30, 13.2-38.4, 21.6-30 and 25.8-39.6% dry weight...

  1. Properties of carbon composite paper derived from coconut coir as a function of polytetrafluoroethylene content

    Science.gov (United States)

    Destyorini, Fredina; Indriyati; Indayaningsih, Nanik; Prihandoko, Bambang; Zulfia Syahrial, Anne

    2018-03-01

    The carbon composite papers were produced by utilizing carbon materials from coconut coir. In the present work, carbon composite papers (CCP) were prepared by mixing carbon materials in the form of powder and fibre with polymer (ethylene vinyl acetate and polyethylene glycol) in xylene at 100°C. Then, polytetrafluoroethylene (PTFE) with different content was used to treat the surface of CCP. The properties of PTFE-coated CCP were analysed by means of contact angle measurement, tensile testing, porosity, density, and electrical conductivity measurements. As expected, all CCP’s surfaces treated with PTFE were found to be hydrophobic with contact angle >120° and relatively constant during 60 minutes measurement. Furthermore, water contact angle, density, and mechanical properties of CCP generally increase with increasing PTFE content. However, the porosity and electrical conductivity of CCP decrease slightly as the PTFE content increased from 0 wt% to 30 wt%. Based on the observation and analysis, the optimum PTFE content on CCP was 20 %, in which the mechanical properties and hydrophobicity behaviour were improved significantly, but it was only caused a very small drop in porosity and electrical conductivity

  2. Magnetism as indirect tool for carbon content assessment in nickel nanoparticles

    Science.gov (United States)

    Oumellal, Y.; Magnin, Y.; Martínez de Yuso, A.; Aguiar Hualde, J. M.; Amara, H.; Paul-Boncour, V.; Matei Ghimbeu, C.; Malouche, A.; Bichara, C.; Pellenq, R.; Zlotea, C.

    2017-12-01

    We report a combined experimental and theoretical study to ascertain carbon solubility in nickel nanoparticles embedded into a carbon matrix via the one-pot method. This original approach is based on the experimental characterization of the magnetic properties of Ni at room temperature and Monte Carlo simulations used to calculate the magnetization as a function of C content in Ni nanoparticles. Other commonly used experimental methods fail to accurately determine the chemical analysis of these types of nanoparticles. Thus, we could assess the C content within Ni nanoparticles and it decreases from 8 to around 4 at. % with increasing temperature during the synthesis. This behavior could be related to the catalytic transformation of dissolved C in the Ni particles into graphite layers surrounding the particles at high temperature. The proposed approach is original and easy to implement experimentally since only magnetization measurements at room temperature are needed. Moreover, it can be extended to other types of magnetic nanoparticles dissolving carbon.

  3. Uranium concentration in fossils

    International Nuclear Information System (INIS)

    Okano, J.; Uyeda, C.

    1988-01-01

    Recently it is known that fossil bones tend to accumulate uranium. The uranium concentration, C u in fossils has been measured so far by γ ray spectroscopy or by fission track method. The authors applied secondary ion mass spectrometry, SIMS, to detect the uranium in fossil samples. The purpose of this work is to investigate the possibility of semi-quantitative analyses of uranium in fossils, and to study the correlation between C u and the age of fossil bones. The further purpose of this work is to apply SIMS to measure the distribution of C u in fossil teeth

  4. Characterization and observation of water-based nanofluids quench medium with carbon particle content variation

    Science.gov (United States)

    Yahya, S. S.; Harjanto, S.; Putra, W. N.; Ramahdita, G.; Kresnodrianto, Mahiswara, E. P.

    2018-05-01

    Recently, nanofluids have been widely used in heat treatment industries as quench medium with better quenching performance. The thermal conductivity of nanofluids is higher compared to conventional quench medium such as polymer, water, brine, and petroleum-based oil. This characteristic can be achieved by mixing high thermal conductivity particles in nanometer scale with a fluid as base. In this research, carbon powder and distilled water were used as nanoparticles and base respectively. The carbon source used in this research was laboratory grade carbon powder, and activated carbon as a cheaper alternative source. By adjusting the percentage of dispersed carbon particles, thermal conductivity of nanofluids could be controlled as needed. To obtain nanoscale carbon particles, planetary ball mill was used to grind laboratory-grade carbon and active carbon powder to further decrease its particle size. This milling method will provide nanoparticles with lower production cost. Milling speed and duration were set at 500 rpm and 15 hours. Scanning electron microscope (SEM) and Energy Dispersive X-Ray (EDX) were carried out respectively to determine the particle size, material identification, particle morphology. The carbon nanoparticle content in nanofluids quench mediums for this research were varied at 0.1, 0.3, and 0.5 % vol. Furthermore, these mediums were used to quench AISI 1045 carbon steel samples which had been annealed at 1000 °C. Hardness testing and metallography observation were then conducted to check the effect of different quench medium in steel samples. Preliminary characterizations showed that the carbon particle dimension after milling was hundreds of nanometers, or still in sub-micron range. Therefore, the milling process parameters are need to be optimized further. EDX observation in laboratory-grade carbon powder showed that the powder was pure carbon as expected for, but in activated carbon has some impurities. The nanofluid itself, however, was

  5. Sedimentology of SPICE (Steptoean positive carbon isotope excursion): A high-resolution trace fossil and microfabric analysis of the middle to late Cambrian Alum Shale Formation, southern Sweden

    Science.gov (United States)

    Egenhoff, Sven; Fishman, Neil; Ahlberg, Per; Maletz, Jorg; Jackson, Allison; Kolte, Ketki; Lowers, Heather; Mackie, James; Newby, Warren; Petrowsky, Matthew

    2015-01-01

    The Cambrian Alum Shale Formation in the Andrarum-3 core from Scania, southern Sweden, consists of black siliciclastic mudstone with minor carbonate intercalations. Four facies comprise three siliciclastic mudstones and one fine-grained carbonate. The facies reflect deposition along a transect from deep ramp to basin on a Cambrian shelf. The three mudstone facies contain abundant clay clasts and laterally variable siltstone laminae. Bed-load transport processes seem to have dominated deposition on this deep shelf. These sedimentary rocks record mainly event deposition, and only relatively few, thin laminae probably resulted from suspension settling. The Alum Shale Formation deep shelf did not show a bioturbation gradient, but fecal strings are common and Planolites burrows are rare in all mudstone facies. Evidence for biotic colonization indicates that this mudstone environment was not persistently anoxic, but rather was most likely intermittently dysoxic. The Alum Shale Formation in the Andrarum-3 core shows an overall decrease of grain size, preserved energy indicators, and carbonate content upsection interpreted to reflect a deepening upward. The succession can also be divided into four small-scale fining-upward cycles that represent deepening, and four overlying coarsening-upward cycles that represent upward shallowing.

  6. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

    Science.gov (United States)

    Alan F. Talhelm; Kurt S. Pregitzer; Mark E. Kubiske; Donald R. Zak; Courtney E. Campany; Andrew J. Burton; Richard E. Dickson; George R. Hendrey; J. G. Isebrands; Keith F. Lewin; John Nagy; David F. Karnosky

    2014-01-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and tropospheric ozone (O3) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment...

  7. Late quaternary fluctuations in carbonate and carbonate ion content in the northern Indian ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.

    -normalized carbonate ion (CO3=*) range from 90 to 125µmol kg-1 in the tropical region of the world oceans with a weight los of 0.3 ± 0.05µg mol -1kg-1 (Broecker and Clark, 201d). Botm water CO3=* concentration bathing the core tops are in the range of 88 to 13 μmolkg-1...

  8. Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO3@C composites as anode materials for lithium-ion batteries

    Science.gov (United States)

    Fan, Fuqiang; Fang, Guoqing; Zhang, Ruixue; Xu, Yanhui; Zheng, Junwei; Li, Decheng

    2014-08-01

    A series of core-shell carbon coated amorphous CoSnO3 (CoSnO3@C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge-discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO3@C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g-1 after 100 cycles.

  9. Diurnal fluctuations in cotton leaf carbon export, carbohydrate content, and sucrose synthesizing enzymes.

    Science.gov (United States)

    Hendrix, D L; Huber, S C

    1986-06-01

    In fully expanded leaves of greenhouse-grown cotton (Gossypium hirsutum L., cv Coker 100) plants, carbon export, starch accumulation rate, and carbon exchange rate exhibited different behavior during the light period. Starch accumulation rates were relatively constant during the light period, whereas carbon export rate was greater in the afternoon than in the morning even though the carbon exchange rate peaked about noon. Sucrose levels increased throughout the light period and dropped sharply with the onset of darkness; hexose levels were relatively constant except for a slight peak in the early morning. Sucrose synthase, usually thought to be a degradative enzyme, was found in unusually high activities in cotton leaf. Both sucrose synthase and sucrose phosphate synthetase activities were found to fluctuate diurnally in cotton leaves but with different rhythms. Diurnal fluctuations in the rate of sucrose export were generally aligned with sucrose phosphate synthase activity during the light period but not with sucrose synthase activity; neither enzyme activity correlated with carbon export during the dark. Cotton leaf sucrose phosphate synthase activity was sufficient to account for the observed carbon export rates; there is no need to invoke sucrose synthase as a synthetic enzyme in mature cotton leaves. During the dark a significant correlation was found between starch degradation rate and leaf carbon export. These results indicate that carbon partitioning in cotton leaf is somewhat independent of the carbon exchange rate and that leaf carbon export rate may be linked to sucrose formation and content during the light period and to starch breakdown in the dark.

  10. The comparison of fossil carbon fraction and greenhouse gas emissions through an analysis of exhaust gases from urban solid waste incineration facilities.

    Science.gov (United States)

    Kim, Seungjin; Kang, Seongmin; Lee, Jeongwoo; Lee, Seehyung; Kim, Ki-Hyun; Jeon, Eui-Chan

    2016-10-01

    In this study, in order to understand accurate calculation of greenhouse gas emissions of urban solid waste incineration facilities, which are major waste incineration facilities, and problems likely to occur at this time, emissions were calculated by classifying calculation methods into 3 types. For the comparison of calculation methods, the waste characteristics ratio, dry substance content by waste characteristics, carbon content in dry substance, and (12)C content were analyzed; and in particular, CO2 concentration in incineration gases and (12)C content were analyzed together. In this study, 3 types of calculation methods were made through the assay value, and by using each calculation method, emissions of urban solid waste incineration facilities were calculated then compared. As a result of comparison, with Calculation Method A, which used the default value as presented in the IPCC guidelines, greenhouse gas emissions were calculated for the urban solid waste incineration facilities A and B at 244.43 ton CO2/day and 322.09 ton CO2/day, respectively. Hence, it showed a lot of difference from Calculation Methods B and C, which used the assay value of this study. It is determined that this was because the default value as presented in IPCC, as the world average value, could not reflect the characteristics of urban solid waste incineration facilities. Calculation Method B indicated 163.31 ton CO2/day and 230.34 ton CO2/day respectively for the urban solid waste incineration facilities A and B; also, Calculation Method C indicated 151.79 ton CO2/day and 218.99 ton CO2/day, respectively. This study intends to compare greenhouse gas emissions calculated using (12)C content default value provided by the IPCC (Intergovernmental Panel on Climate Change) with greenhouse gas emissions calculated using (12)C content and waste assay value that can reflect the characteristics of the target urban solid waste incineration facilities. Also, the concentration and (12)C content

  11. Sequestration of organochlorine pesticides in soils of distinct organic carbon content

    International Nuclear Information System (INIS)

    Zhang Na; Yang Yu; Tao Shu; Liu Yan; Shi Kelu

    2011-01-01

    In the present study, five soil samples with organic carbon contents ranging from 0.23% to 7.1% and aged with technical dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) for 15 months were incubated in a sealed chamber to investigate the dynamic changes of the OCP residues. The residues in the soils decreased over the incubation period and finally reached a plateau. Regression analysis showed that degradable fractions of OCPs were negatively correlated with soil organic carbon (SOC) except for α-HCH, while no correlation was found between degradation rate and SOC, which demonstrated that SOC content determines the OCP sequestration fraction in soil. Analysis of the ratio of DDT and its primary metabolites showed that, since it depends on differential sequestration among them, magnitude of (p,p'-DDE + p,p'-DDD)/p,p'-DDT is not a reliable criterion for the identification of new DDT sources. - Research highlights: → Soil organic carbon content determines the OCP sequestration fraction in soil. → Magnitude of (p,p'-DDE + p,p'-DDD)/p,p'-DDT is not a reliable criterion for the identification of new DDT sources. → The more hydrophobic compounds have relatively higher sequestration fractions in soils with SOC contents >2%. → DDD may have higher sorption by soil organic matter than DDE. - The effect of soil organic matter on the sequestration of organochlorine pesticides (HCHs and DDTs) in soils was investigated in an innovative microcosm chamber.

  12. [Study on the content and carbon isotopic composition of water dissolved inorganic carbon from rivers around Xi'an City].

    Science.gov (United States)

    Guo, Wei; Li, Xiang-Zhong; Liu, Wei-Guo

    2013-04-01

    In this study, the content and isotopic compositions of water dissolved inorganic carbon (DIC) from four typical rivers (Chanhe, Bahe, Laohe and Heihe) around Xi'an City were studied to trace the possible sources of DIC. The results of this study showed that the content of DIC in the four rivers varied from 0.34 to 5.66 mmol x L(-1) with an average value of 1.23 mmol x L(-1). In general, the content of DIC increased from the headstream to the river mouth. The delta13C(DIC) of four rivers ranged from -13.3 per thousand to -7.2 per thousand, with an average value of -10.1 per thousand. The delta13C(DIC) values of river water were all negative (average value of -12.6 per thousand) at the headstream of four rivers, but the delta13C(DIC) values of downstream water were more positive (with an average value of -9.4 per thousand). In addition, delta13C(DIC) of river water showed relatively negative values (the average value of delta13C(DIC) was -10.5 per thousand) near the estuary of the rivers. The variation of the DIC content and its carbon isotope suggested that the DIC sources of the rivers varied from the headstream to the river mouth. The negative delta13C(DIC) value indicated that the DIC may originate from the soil CO2 at the headstream of the rivers. On the other hand, the delta13C(DIC) values of river water at the middle and lower reaches of rivers were more positive, and it showed that soil CO2 produced by respiration of the C4 plants (like corn) and soil carbonates with positive delta13C values may be imported into river water. Meanwhile, the input of pollutants with low delta13C(DIC) values may result in a decrease of delta13C(DIC) values in the rivers. The study indicated that the DIC content and carbon isotope may be used to trace the sources of DIC in rivers around Xi'an City. Our study may provide some basic information for tracing the sources of DIC of rivers in the small watershed area in the Loess Plateau of China.

  13. Considering Organic Carbon for Improved Predictions of Clay Content from Water Vapor Sorption

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

    2014-01-01

    Accurate determination of the soil clay fraction (CF) is of crucial importance for characterization of numerous environmental, agricultural, and engineering processes. Because traditional methods for measurement of the CF are laborious and susceptible to errors, regression models relating the CF...... to water vapor sorption isotherms that can be rapidly measured with a fully automated vapor sorption analyzer are a viable alternative. In this presentation we evaluate the performance of recently developed regression models based on comparison with standard CF measurements for soils with high organic...... carbon (OC) content and propose a modification to improve prediction accuracy. Evaluation of the CF prediction accuracy for 29 soils with clay contents ranging from 6 to 25% and with OC contents from 2.0 to 8.4% showed that the models worked reasonably well for all soils when the OC content was below 2...

  14. Assessment of pre-industrial carbon dioxide content in the atmosphere using hydro-chemical data

    International Nuclear Information System (INIS)

    Heans, K.A.; Liaxin, Y.I.

    2001-01-01

    A hydrochemical method has been developed to calculate concentrations of carbon dioxide (CO 2 ) in the pre-industrial atmosphere and its relationship to climatic change. The following factors affect the Earth's climate: (1) the sun with all its processes, (2) the attraction of the moon that limits the axis of inclination of the Earth, and (3) the cycle of carbon dioxide and the greenhouse effect. An imbalance in the climate system would be a major global disaster that could be detrimental for life on Earth. Recent studies and temperature measurements have shown a trend in which air temperature has increased in the troposphere in the last 100 years, affecting the normal development of natural processes. Various phenomena result from climatic change, or the gradual heating of the Earth. These include the weakening of the glacial layer that covers the Earth's surface, cycles of prolonged slowing in freeze and thaw periods of aquatic surfaces, and increased air temperature in the troposphere which can also causes abnormal fluctuations of temperature in the atmosphere, resulting in heat waves and droughts. Gradual heating of the Earth can also result in rainy periods that produce devastating floods, hurricanes and extreme winds. Changes in water temperature can influence pH levels which affect certain marine species. An increase of 5 degrees C in the global average atmospheric temperature has created changes in 420 physical processes as well as in the behavior of plants and animals. The author stated that the most drastic factor that affects the balance of the Earth's climate is the actions of man interfering with the carbon cycle, as carbon dioxide plays a vital role in the formation of the greenhouse effect. The problem results from an imbalance of the carbon dioxide cycle when CO 2 emissions are increased through the combustion of fossil fuels. It was determined that before the beginning of the Industrial Revolution, carbon dioxide in the atmosphere was 256 ppm

  15. Study of two new methods of geochronometry: dating method of carbonaceous formations by U-series disequilibrium gamma spectrometry; ESR dating method of rich U-content fossil dental enamel

    International Nuclear Information System (INIS)

    Ma, Jean-Luc

    1984-01-01

    First, the U-series disequilibrium dating method was re-examined using non-destructive γ-spectrometry. A new low-background (≤ 10 ppb U- equivalent) Ge-HP γ-spectrometer has been used to date travertine with small U-content (∼ 0.1 ppm) and low (≤ 5%) Th/U , content, by comparison with old-limestone γ-spectra. Second, a new ESR dating method has been developed using fossil dental enamel which is rich in U-content (10 - 100 ppm). Both methods were applied to Arago Cave (Tautavel, France): - with an ionium-age of 120 ka (10%), the upper travertine seems to have been set up during the Riss-deglaciation period. - the high (∼ 50%) Th/U-content samples of the intermediate travertine are un-datable. - the ESR-age of EQUUS mosbachensis enamel is 400 ka (10%) for the G-soil of Arago. XXI H. erectus, and 600 ka (10%) for the Q-soil above (- 1 m) of the lower travertine of which Io-age is older than 350 ka. (author)

  16. Carbon dioxide emissions from non-energy use of fossil fuels. Summary of key issues and conclusions from the country analyses

    International Nuclear Information System (INIS)

    Patel, Martin; Neelis, Maarten; Gielen, Dolf; Olivier, Jos; Simmons, Tim; Theunis, Jan

    2005-01-01

    The non-energy use of fossil fuels is a source of carbon dioxide (CO 2 ) emissions that is not negligible and has been increasing substantially in the last three decades. Current emission estimates for this source category are subject to major uncertainties. One important reason is that non-energy use as published in energy statistics is not defined in a consistent manner, rendering calculation results based on these data incomparable across countries (concerns in particular the Intergovernmental Panel on Climate Change (IPCC) Reference Approach). Further reasons are the complexity and interlinkage of the energy and material flows in the chemical/petrochemical sector and the current use of storage fractions as default values in the IPCC Reference Approach, which are based on a different definition of storage and refer to other flows than those available from energy statistics. Several other shortcomings of the IPCC Reference Approach are identified in this paper, e.g. the fact that it neglects international trade of synthetic organic products. In order to improve emissions accounting, the Non-Energy Use and CO 2 Emissions (NEU-CO 2 ) network developed a model called Non-Energy Use Emission Accounting Tables (NEAT), which is based on Material Flow Analysis (MFA). The NEAT model and other MFA approaches have been applied to several countries. In this paper, the results for Italy, Japan, Korea, the Netherlands and the USA are compared with the values published in National Communications to the United Framework Convention on Climate Change (UNFCCC). It is shown that the international harmonisation of the data sources (energy statistics) and the methods applied would lead to substantially different emissions results for some countries, in the order of several percent. Moreover, the NEAT model and the other MFA have proved to be a valuable tool to identify errors in energy statistics. These results confirm the need for enhanced efforts to improve and harmonise energy

  17. Environmental costs of fossil fuel energy production

    International Nuclear Information System (INIS)

    Riva, A.; Trebeschi, C.

    1997-01-01

    The costs of environmental impacts caused by fossil fuel energy production are external to the energy economy and normally they are not reflected in energy prices. To determine the environmental costs associated with an energy source a detailed analysis of all environmental impacts of the complete energy cycle is required. The economic evaluation of environmental damages is presented caused by atmospheric emissions produced by fossil fuel combustion for different uses. Considering the emission factors of sulphur oxides, nitrogen oxides, dust and carbon dioxide and the economic evaluation of their environmental damages reported in literature, a range of environmental costs associated with different fossil fuels and technologies is presented. A comparison of environmental costs resulting from atmospheric emissions produced by fossil-fuel combustion for energy production shows that natural gas has a significantly higher environmental value than other fossil fuels. (R.P.)

  18. An optical method for characterizing carbon content in ceramic pot filters.

    Science.gov (United States)

    Goodwin, J Y; Elmore, A C; Salvinelli, C; Reidmeyer, Mary R

    2017-08-01

    Ceramic pot filter (CPF) technology is a relatively common means of household water treatment in developing areas, and performance characteristics of CPFs have been characterized using production CPFs, experimental CPFs fabricated in research laboratories, and ceramic disks intended to be CPF surrogates. There is evidence that CPF manufacturers do not always fire their products according to best practices and the result is incomplete combustion of the pore forming material and the creation of a carbon core in the final CPFs. Researchers seldom acknowledge the existence of potential existence of carbon cores, and at least one CPF producer has postulated that the carbon may be beneficial in terms of final water quality because of the presence of activated carbon in consumer filters marketed in the Western world. An initial step in characterizing the presence and impact of carbon cores is the characterization of those cores. An optical method which may be more viable to producers relative to off-site laboratory analysis of carbon content has been developed and verified. The use of the optical method is demonstrated via preliminary disinfection and flowrate studies, and the results of these studies indicate that the method may be of use in studying production kiln operation.

  19. Converting loss-on-ignition to organic carbon content in arable topsoil: pitfalls and proposed procedure

    DEFF Research Database (Denmark)

    Jensen, Johannes Lund; Christensen, Bent Tolstrup; Schjønning, Per

    2018-01-01

    Assessments of changes in soil organic carbon (SOC) stocks depend heavily on reliable values of SOC content obtained by automated high‐temperature C analysers. However, historical as well as current research often relies on indirect SOC estimates such as loss‐on‐ignition (LOI). In this study, we...... revisit the conversion of LOI to SOC using soil from two long‐term agricultural field experiments and one arable field with different contents of SOC, clay and particles fractions were isolated from the arable soil. Samples were analysed for texture, LOI (500...

  20. Application of laser-produced-plasmas to determination of carbon content in steel

    International Nuclear Information System (INIS)

    Ortiz, M.; Aragon, C.; Aguilera, J.A.; Campos, J.

    1994-01-01

    This paper describes an analytical method to determine carbon content in solid and molten steel. It is based on the study of the emission spectrum from a Nd-YAG laser produced plasma. The light emitted from the plasma is focused to the entrance slit of a spectrometer and detected by an OMA III system. For every laser pulse an spectral range of 100 A are recorded. With the use of time-resolved spectroscopy a precision of 1.6% and a detection limit of 65 ppm of carbon content in steel have been obtained. These values are similar to those of other accurate conventional techniques but using optics fiber and laser excitation it is possible to made sample calibrations in hostile environments. Also, as the analysis are made in real time changes in sample composition can be measured without stopping production processes. (Author) 26 refs

  1. Comparative Environmental Life Cycle Assessment of Alternative Uses of Wastewater Carbon Content

    DEFF Research Database (Denmark)

    Kroghsbo, Nena; Nicolaisen, Janna; Wenzel, Henrik

    Alternative scenarios for the wastewater and sludge treatment configurations in urban wastewater treatment were studied with the aim of comparing their environmental aspects. As the reference, a conventional activated sludge treatment was chosen including a primary settling and biogas made from...... the mixed primary and secondary sludge. This reference was then compared to an alternative use of the mixed sludge for the fermentative generation of polyhydroxyalkanoates, PHA and subsequent use of the PHA to substitute polypropylene on the polymer markets. This comparison allows for assessing...... the environmental priorities between biogas and PHA formation from the carbon content of the sludge. Further, the elimination of the primary settling with the aim of using the carbon content of the wastewater for enhanced nitrogen removal in the activated sludge process was studied. This comparison allows...

  2. Application of laser-produced-plasmas to determination of carbon content in steel

    International Nuclear Information System (INIS)

    Ortiz, M.; Aragon, C.; Aguilera, J. A.; Campos, J.

    1994-01-01

    This paper describes an analytical method to determine carbon content in solid and molten steel. It is based on the study of the emission spectrum from a Nd-YAG laser produced plasma. The light emitted from the plasma is focused to the entrance slit of a spectrometer and detected by an OMA III system. For every laser pulse an spectral range of 100 A are recorded. With the use of time-resolved spectroscopy a precision of 1.6 % and a detection limit of 65 ppm of carbon content in steel have been obtained. These values are similar to those of other accurate conventional techniques but using optics fiber and laser excitation it is possible to made sample calibrations in hostile environments. Also, as the analysis are made in real time changes in sample composition can be measured without stopping production processes. (Author) 26 refs

  3. Carbon as Investment Risk—The Influence of Fossil Fuel Divestment on Decision Making at Germany’s Main Power Providers

    Directory of Open Access Journals (Sweden)

    Dagmar Kiyar

    2015-09-01

    Full Text Available German electricity giants have recently taken high-level decisions to remove selected fossil fuel operations from their company portfolio. This new corporate strategy could be seen as a direct response to the growing global influence of the fossil fuel divestment campaign. In this paper we ask whether the divestment movement currently exerts significant influence on decision-making at the top four German energy giants—E.On, RWE, Vattenfall and EnBW. We find that this is not yet the case. After describing the trajectory of the global fossil fuel divestment campaign, we outline four alternative influences on corporate strategy that, currently, are having a greater impact than the divestment movement on Germany’s power sector. In time, however, clear political decisions and strong civil support may increase the significance of climate change concerns in the strategic management of the German electricity giants.

  4. Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO3@C composites as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Fan, Fuqiang; Fang, Guoqing; Zhang, Ruixue; Xu, Yanhui; Zheng, Junwei; Li, Decheng

    2014-01-01

    Highlights: • The thickness of carbon coating layers can be successfully controlled through varying molar concentration of aqueous glucose solution. • Coating carbon thickness and carbon content are two important factors on the electrochemical performances of CoSnO3@C. • CoSnO 3 @C under optimized conditions exhibits the optimal balance between the volume buffering effect and reversible capacity. • As-prepared CoSnO 3 @C under optimized conditions shows excellent electrochemical performances, whose reversible capacity could reach 491 mA h g −1 after 100 cycles. - Abstract: A series of core–shell carbon coated amorphous CoSnO 3 (CoSnO 3 @C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge–discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO 3 @C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g −1 after 100 cycles

  5. Effect of carbon content on microstructure and mechanical properties of hot-rolled low carbon 12Cr-Ni stainless steel

    International Nuclear Information System (INIS)

    Zheng, H.; Ye, X.N.; Li, J.D.; Jiang, L.Z.; Liu, Z.Y.; Wang, G.D.; Wang, B.S.

    2010-01-01

    Research highlights: → Hot-rolled ultra low carbon martensite is characterized by dislocation cells substructure. → The formation of dislocation cells is attributed to high Ms and low interstitial atoms content. → Hot-rolled ultra low carbon 12Cr-Ni stainless steel has excellent impact toughness. → Delta ferrite deteriorates the impact toughness of hot-rolled 12Cr-Ni stainless steel. - Abstract: 12Cr-Ni stainless steels containing different carbon contents from 0.004 wt.% to 0.034 wt.% were hot-rolled and air-cooled. Their corresponding microstructures were observed with optical microscope and transmission electron microscope, and the Vickers hardness, tensile and impact tests were also carried out. It was found that the martensitic morphology was significantly influenced by carbon content. The as-received ultra low carbon martensite in the steel containing 0.004 wt.% C is characterized by dislocation cells substructure. The formation of dislocation cells is attributed to high martensite finishing point (above 400 deg. C) and low interstitial atoms content. On the other hand, the martensite in the steel containing 0.034 wt.% C consists mainly of typical martensite laths because of low martensite finishing point and high interstitial atoms content which hinder dislocation motion. Furthermore, carbon content has an evident effect on the mechanical properties of 12Cr-Ni steels. The hardness and strength of the as-received steels increase with an increase in carbon content, but their elongation and impact toughness decrease with the carbon content. The steel containing 0.004 wt.% C has excellent impact toughness due to the ultra low carbon content in the martensite composed of dislocation cells.

  6. Distribution of cesium-137 in Japanese forest soils. Correlation with the contents of organic carbon

    International Nuclear Information System (INIS)

    Takenaka, Chisato; Onda, Yuichi; Hamajima, Yasunori

    1998-01-01

    The spatial and vertical distributions of 137 Cs in surface soils were surveyed and analyzed then correlated with the contents of organic carbon in the hinoki (Chamaecyparis obtusa Sieb. et Zucc.) plantation forest and secondary forest dominated by red pine (Pinus densiflora Sieb. et Zucc.) in Japan. The spatial variation of 137 Cs activity was observed in the surface soil around the red pine. The average activity of 16 samples around the tree is 42.4 Bq/kg and the standard deviation is 25.9 Bq/kg. This finding indicates the importance in the selection of a sampling site and the number of samples from the surface soils especially around a tree. For the vertical distribution of 137 Cs activity, it was found that the concentration in the surface soil is highest, 149 Bq/kg in the hinoki stand and 101 Bq/kg in the red pine stand, and decreases with depth. The relationship between 137 Cs activity and carbon content in the forest soil was investigated in two undisturbed forest stands. The relations were more precisely expressed using an exponential equation than by a linear equation. From the same forest, similar regression equations were obtained. This indicates that the distribution of 137 Cs could be characterized by the organic carbon content in an undisturbed forest. It is also suggested that the coefficient values in the regression equation help to define the movement of 137 Cs accompanying the decomposition of organic matter

  7. Main Feedbacks Between Oxidizable Carbon Content and Selected Soil Characteristic of Chernozem

    Directory of Open Access Journals (Sweden)

    Vítězslav Vlček

    2015-01-01

    Full Text Available Anthropogenic pressure on our agricultural land is culminating last hundred years, especially after 1948, not only because of only massive application of mineral fertilizers but also because of land consolidation and subsequent accelerated water and wind erosion and use of mechanization. This article focuses on main demonstration of feedbacks especially with oxidizable carbon which can negatively affect soil as a homeostatic system. Oxidizable carbon, as the basis of soil humus, is crucial for maintaining soil fertility and for its resistance to further degradation factors affecting the soil. 35 chernozem sites were selected in South Moravia region. These soils had been probably used for their fertility and availability before the turn of the AD. Unfortunately, their long-term agricultural use has resulted in adverse impact on their quality.This way, shallower forms of erosion were often formed. These erosion forms are omitted for the purposes of our study there. For this work, locations with preserved chernic (i.e. diagnostic horizon, as the horizon with less anthropogenic influence, were selected. Relations between a grain size (clay, silt and sand particles, exchange reaction in soil, sorption capacity, oxidizable carbon content, total nitrogen content and content of selected potentially acceptable elements (Ca, Mg were monitored.

  8. Digital mapping of soil organic carbon contents and stocks in Denmark.

    Science.gov (United States)

    Adhikari, Kabindra; Hartemink, Alfred E; Minasny, Budiman; Bou Kheir, Rania; Greve, Mette B; Greve, Mogens H

    2014-01-01

    Estimation of carbon contents and stocks are important for carbon sequestration, greenhouse gas emissions and national carbon balance inventories. For Denmark, we modeled the vertical distribution of soil organic carbon (SOC) and bulk density, and mapped its spatial distribution at five standard soil depth intervals (0-5, 5-15, 15-30, 30-60 and 60-100 cm) using 18 environmental variables as predictors. SOC distribution was influenced by precipitation, land use, soil type, wetland, elevation, wetness index, and multi-resolution index of valley bottom flatness. The highest average SOC content of 20 g kg(-1) was reported for 0-5 cm soil, whereas there was on average 2.2 g SOC kg(-1) at 60-100 cm depth. For SOC and bulk density prediction precision decreased with soil depth, and a standard error of 2.8 g kg(-1) was found at 60-100 cm soil depth. Average SOC stock for 0-30 cm was 72 t ha(-1) and in the top 1 m there was 120 t SOC ha(-1). In total, the soils stored approximately 570 Tg C within the top 1 m. The soils under agriculture had the highest amount of carbon (444 Tg) followed by forest and semi-natural vegetation that contributed 11% of the total SOC stock. More than 60% of the total SOC stock was present in Podzols and Luvisols. Compared to previous estimates, our approach is more reliable as we adopted a robust quantification technique and mapped the spatial distribution of SOC stock and prediction uncertainty. The estimation was validated using common statistical indices and the data and high-resolution maps could be used for future soil carbon assessment and inventories.

  9. Fossil fuel usage and the environment

    International Nuclear Information System (INIS)

    Klass, D.L.

    1991-01-01

    The Greenhouse Effect and global warming, ozone formation in the troposphere, ozone destruction in the stratosphere, and acid rain are important environmental issues. The relationship of fossil fuel usage to some of these issues is discussed. Data on fossil fuel consumption and the sources and sinks of carbon dioxide, carbon monoxide, methane, nitrogen and sulfur oxides, and ozone indicate that natural gas provides lower emissions of carbon dioxide, carbon monoxide, and nitrogen and sulfur oxides than other fossil fuels. Global emissions of methane from the gas industry are significantly less than those from other anthropogenic activities and natural sources, and methane plays an important role along with carbon monoxide and nitric oxide in tropospheric ozone formation. Reductions in any or all of these air pollutants would reduce ozone in the lower atmosphere. Several remedial measures have been or are being implemented in certain countries to reduce fossil fuel emissions. These include removal of emissions from the atmosphere by new biomass growth, fuel substitution by use of cleaner burning fuels for stationary and mobile sources, and fossil fuel combustion at higher efficiencies. It is unlikely that concerted environmental action by all governments of the world will occur soon, but much progress has been made to achieve clean air

  10. Electrochemical Determination of Caffeine Content in Ethiopian Coffee Samples Using Lignin Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Meareg Amare

    2017-01-01

    Full Text Available Lignin film was deposited at the surface of glassy carbon electrode potentiostatically. In contrast to the unmodified glassy carbon electrode, an oxidative peak with an improved current and overpotential for caffeine at modified electrode showed catalytic activity of the modifier towards oxidation of caffeine. Linear dependence of peak current on caffeine concentration in the range 6×10-6 to 100×10-6 mol L−1 with determination coefficient and method detection limit (LoD = 3 s/slope of 0.99925 and 8.37×10-7 mol L−1, respectively, supplemented by recovery results of 93.79–102.17% validated the developed method. An attempt was made to determine the caffeine content of aqueous coffee extracts of Ethiopian coffees grown in four coffee cultivating localities (Wonbera, Wolega, Finoteselam, and Zegie and hence to evaluate the correlation between users preference and caffeine content. In agreement with reported works, caffeine contents (w/w% of 0.164 in Wonbera coffee; 0.134 in Wolega coffee; 0.097 in Finoteselam coffee; and 0.089 in Zegie coffee were detected confirming the applicability of the developed method for determination of caffeine in a complex matrix environment. The result indicated that users’ highest preference for Wonbera and least preference for Zegie cultivated coffees are in agreement with the caffeine content.

  11. Electrochemical Determination of Caffeine Content in Ethiopian Coffee Samples Using Lignin Modified Glassy Carbon Electrode.

    Science.gov (United States)

    Amare, Meareg; Aklog, Senait

    2017-01-01

    Lignin film was deposited at the surface of glassy carbon electrode potentiostatically. In contrast to the unmodified glassy carbon electrode, an oxidative peak with an improved current and overpotential for caffeine at modified electrode showed catalytic activity of the modifier towards oxidation of caffeine. Linear dependence of peak current on caffeine concentration in the range 6 × 10 -6 to 100 × 10 -6  mol L -1 with determination coefficient and method detection limit (LoD = 3 s/slope) of 0.99925 and 8.37 × 10 -7  mol L -1 , respectively, supplemented by recovery results of 93.79-102.17% validated the developed method. An attempt was made to determine the caffeine content of aqueous coffee extracts of Ethiopian coffees grown in four coffee cultivating localities (Wonbera, Wolega, Finoteselam, and Zegie) and hence to evaluate the correlation between users preference and caffeine content. In agreement with reported works, caffeine contents (w/w%) of 0.164 in Wonbera coffee; 0.134 in Wolega coffee; 0.097 in Finoteselam coffee; and 0.089 in Zegie coffee were detected confirming the applicability of the developed method for determination of caffeine in a complex matrix environment. The result indicated that users' highest preference for Wonbera and least preference for Zegie cultivated coffees are in agreement with the caffeine content.

  12. Content

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    secondary levels. In subject matter didactics, the question of content is more developed, but it is still mostly confined to teaching on lower levels. As for higher education didactics, discussions on selection of content are almost non-existent on the programmatic level. Nevertheless, teachers are forced...... curriculum, in higher education, and to generate analytical categories and criteria for selection of content, which can be used for systematic didactical reflection. The larger project also concerns reflection on and clarification of the concept of content, including the relation between content at the level......Aim, content and methods are fundamental categories of both theoretical and practical general didactics. A quick glance in recent pedagogical literature on higher education, however, reveals a strong preoccupation with methods, i.e. how teaching should be organized socially (Biggs & Tang, 2007...

  13. Facile synthesis of cellulose-based carbon with tunable N content for potential supercapacitor application.

    Science.gov (United States)

    Chen, Zehong; Peng, Xinwen; Zhang, Xiaoting; Jing, Shuangshuang; Zhong, Linxin; Sun, Runcang

    2017-08-15

    Producing hierarchical porous N-doped carbon from renewable biomass is an essential and sustainable way for future electrochemical energy storage. Herein we cost-efficiently synthesized N-doped porous carbon from renewable cellulose by using urea as a low-cost N source, without any activation process. The as-prepared N-doped porous carbon (N-doped PC) had a hierarchical porous structure with abundant macropores, mesopores and micropores. The doping N resulted in more disordered structure, and the doping N content in N-doped PC could be easily tunable (0.68-7.64%). The doping N functionalities could significantly improve the supercapacitance of porous carbon, and even a little amount of doping N (e.g. 0.68%) could remarkably improve the supercapacitance. The as-prepared N-doped PC with a specific surface area of 471.7m 2 g -1 exhibited a high specific capacitance of 193Fg -1 and a better rate capability, as well as an outstanding cycling stability with a capacitance retention of 107% after 5000 cycles. Moreover, the N-doped porous carbon had a high energy density of 17.1Whkg -1 at a power density of 400Wkg -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Adsorption of ionizable organic contaminants on multi-walled carbon nanotubes with different oxygen contents

    International Nuclear Information System (INIS)

    Li Xiaona; Zhao Huimin; Quan Xie; Chen Shuo; Zhang Yaobin; Yu Hongtao

    2011-01-01

    Multi-walled carbon nanotubes (MWNTs), which are considered to be promising candidates for the adsorption of toxic organics, are released into aqueous environment with their increasing production and application. In this study, the adsorption behaviors of five structurally related ionizable organic contaminants namely perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonamide (PFOSA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-n-nonylphenol (4-NP) onto MWNTs with different oxygen contents (3.84-22.85%) were investigated. The adsorption kinetics was investigated and simulated with pseudo-second-order model. The adsorption isotherms were found to be fitted with Freundlich model and influenced by both the properties of organic chemicals and the oxygen contents of MWNTs. As adsorption capacity decreases dramatically with the increasing of oxygen contents, the MWNTs with the lowest oxygen contents possess the highest adsorption capacity among four MWNTs. For the MWNTs with the oxygen contents of 3.84%, the adsorption affinity related with hydrophobic interaction and π-electron polarizability decreased in the order of 4-NP > PFOSA > PFOS > 2,4-D > PFOA. Furthermore, the adsorption characters of five contaminants were affected by solution pH and solute pK a considering electrostatic repulse force and hydrogen bonding, which showed the adsorption of MWNTs with lower oxygen content is much sensitive to solution chemistry.

  15. Optimization of supercritical carbon dioxide extraction of Piper Betel Linn leaves oil and total phenolic content

    Science.gov (United States)

    Aziz, A. H. A.; Yunus, M. A. C.; Arsad, N. H.; Lee, N. Y.; Idham, Z.; Razak, A. Q. A.

    2016-11-01

    Supercritical Carbon Dioxide (SC-CO2) Extraction was applied to extract piper betel linn leaves. The piper betel leaves oil was used antioxidant, anti-diabetic, anticancer and antistroke. The aim of this study was to optimize the conditions of pressure, temperature and flowrate for oil yield and total phenolic content. The operational conditions of SC-CO2 studied were pressure (10, 20, 30 MPa), temperature (40, 60, 80 °C) and flowrate carbon dioxide (4, 6, 8 mL/min). The constant parameters were average particle size and extraction regime, 355pm and 3.5 hours respectively. First order polynomial expression was used to express the extracted oil while second order polynomial expression was used to express the total phenolic content and the both results were satisfactory. The best conditions to maximize the total extraction oil yields and total phenolic content were 30 MPa, 80 °C and 4.42 mL/min leading to 7.32% of oil and 29.72 MPa, 67.53 °C and 7.98 mL/min leading to 845.085 mg GAE/g sample. In terms of optimum condition with high extraction yield and high total phenolic content in the extracts, the best operating conditions were 30 MPa, 78 °C and 8 mL/min with 7.05% yield and 791.709 mg gallic acid equivalent (GAE)/g sample. The most dominant condition for extraction of oil yield and phenolic content were pressure and CO2 flowrate. The results show a good fit to the proposed model and the optimal conditions obtained were within the experimental range with the value of R2 was 96.13% for percentage yield and 98.52% for total phenolic content.

  16. Exploring the multiplicity of soil-human interactions: organic carbon content, agro-forest landscapes and the Italian local communities.

    Science.gov (United States)

    Salvati, Luca; Barone, Pier Matteo; Ferrara, Carlotta

    2015-05-01

    Topsoil organic carbon (TOC) and soil organic carbon (SOC) are fundamental in the carbon cycle influencing soil functions and attributes. Many factors have effects on soil carbon content such as climate, parent material, land topography and the human action including agriculture, which sometimes caused a severe loss in soil carbon content. This has resulted in a significant differentiation in TOC or SOC at the continental scale due to the different territorial and socioeconomic conditions. The present study proposes an exploratory data analysis assessing the relationship between the spatial distribution of soil organic carbon and selected socioeconomic attributes at the local scale in Italy with the aim to provide differentiated responses for a more sustainable use of land. A strengths, weaknesses, opportunities and threats (SWOT) analysis contributed to understand the effectiveness of local communities responses for an adequate comprehension of the role of soil as carbon sink.

  17. Correlation Lengths for Estimating the Large-Scale Carbon and Heat Content of the Southern Ocean

    Science.gov (United States)

    Mazloff, M. R.; Cornuelle, B. D.; Gille, S. T.; Verdy, A.

    2018-02-01

    The spatial correlation scales of oceanic dissolved inorganic carbon, heat content, and carbon and heat exchanges with the atmosphere are estimated from a realistic numerical simulation of the Southern Ocean. Biases in the model are assessed by comparing the simulated sea surface height and temperature scales to those derived from optimally interpolated satellite measurements. While these products do not resolve all ocean scales, they are representative of the climate scale variability we aim to estimate. Results show that constraining the carbon and heat inventory between 35°S and 70°S on time-scales longer than 90 days requires approximately 100 optimally spaced measurement platforms: approximately one platform every 20° longitude by 6° latitude. Carbon flux has slightly longer zonal scales, and requires a coverage of approximately 30° by 6°. Heat flux has much longer scales, and thus a platform distribution of approximately 90° by 10° would be sufficient. Fluxes, however, have significant subseasonal variability. For all fields, and especially fluxes, sustained measurements in time are required to prevent aliasing of the eddy signals into the longer climate scale signals. Our results imply a minimum of 100 biogeochemical-Argo floats are required to monitor the Southern Ocean carbon and heat content and air-sea exchanges on time-scales longer than 90 days. However, an estimate of formal mapping error using the current Argo array implies that in practice even an array of 600 floats (a nominal float density of about 1 every 7° longitude by 3° latitude) will result in nonnegligible uncertainty in estimating climate signals.

  18. Modes of fossil preservation

    Science.gov (United States)

    Schopf, J.M.

    1975-01-01

    The processes of geologic preservation are important for understanding the organisms represented by fossils. Some fossil differences are due to basic differences in organization of animals and plants, but the interpretation of fossils has also tended to be influenced by modes of preservation. Four modes of preservation generally can be distinguished: (1) Cellular permineralization ("petrifaction") preserves anatomical detail, and, occasionally, even cytologic structures. (2) Coalified compression, best illustrated by structures from coal but characteristic of many plant fossils in shale, preserves anatomical details in distorted form and produces surface replicas (impressions) on enclosing matrix. (3) Authigenic preservation replicates surface form or outline (molds and casts) prior to distortion by compression and, depending on cementation and timing, may intergrade with fossils that have been subject to compression. (4) Duripartic (hard part) preservation is characteristic of fossil skeletal remains, predominantly animal. Molds, pseudomorphs, or casts may form as bulk replacements following dissolution of the original fossil material, usually by leaching. Classification of the kinds of preservation in fossils will aid in identifying the processes responsible for modifying the fossil remains of both animals and plants. ?? 1975.

  19. Effect of water content and organic carbon on remote sensing of crop residue cover

    Science.gov (United States)

    Serbin, G.; Hunt, E. R., Jr.; Daughtry, C. S. T.; McCarty, G. W.; Brown, D. J.; Doraiswamy, P. C.

    2009-04-01

    Crop residue cover is an important indicator of tillage method. Remote sensing of crop residue cover is an attractive and efficient method when compared with traditional ground-based methods, e.g., the line-point transect or windshield survey. A number of spectral indices have been devised for residue cover estimation. Of these, the most effective are those in the shortwave infrared portion of the spectrum, situated between 1950 and 2500 nm. These indices include the hyperspectral Cellulose Absorption Index (CAI), and advanced multispectral indices, i.e., the Lignin-Cellulose Absorption (LCA) index and the Shortwave Infrared Normalized Difference Residue Index (SINDRI), which were devised for the NASA Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor. Spectra of numerous soils from U.S. Corn Belt (Indiana and Iowa) were acquired under wetness conditions varying from saturation to oven-dry conditions. The behavior of soil reflectance with water content was also dependent on the soil organic carbon content (SOC) of the soils, and the location of the spectral bands relative to significant water absorptions. High-SOC soils showed the least change in spectral index values with increase in soil water content. Low-SOC soils, on the other hand, showed measurable difference. For CAI, low-SOC soils show an initial decrease in index value followed by an increase, due to the way that water content affects CAI spectral bands. Crop residue CAI values decrease with water content. For LCA, water content increases decrease crop residue index values and increase them for soils, resulting in decreased contrast. SINDRI is also affected by SOC and water content. As such, spatial information on the distribution of surface soil water content and SOC, when used in a geographic information system (GIS), will improve the accuracy of remotely-sensed crop residue cover estimates.

  20. Dating fossil opal phytoliths

    International Nuclear Information System (INIS)

    Lentfer, C.; Boyd, B.; Torrence, R.

    1999-01-01

    Full text: Opal phytoliths are microscopic silica bodies formed by the precipitation of hydrated silica dioxide (SiO 2 nH 2 0) in, around and between cell walls. They are relatively resistant to degradation in most environments and thus, can occur in large quantities in palaeosediments. Consequently, they are valuable tools for environmental reconstruction. Furthermore, phytoliths are often the only recoverable organic material in well oxidised sediments, the occluded carbon provides the opportunity for dating sediment whose ages have previously been difficult to determine, and thus, increase the potential for fine resolution determination of environmental change. This poster describes the results of an investigation assessing the viability of AMS radiocarbon dating of fossil phytolith inclusions using samples from Garua Island, West New Britain, PNG. Thirteen phytolith samples, isolated from sediments previously dated using tephrastratigraphy and C14 dating of macroremains of nutshells and wood charcoal, were used in the analysis. As a control measure, thirteen parallel samples of microscopic charcoal were also dated using AMS. The results show that the AMS dates for the microscopic charcoal samples are consistent with ages anticipated from the other dating methods, for all but one sample. However, the dates for eight of the thirteen phytolith samples are considerably younger than expected. This bias could be explained by several factors, including downwashing of phytolith through soils, bioturbation, carbon exchange through the siliceous matrix of the phytolith bodies, and contamination from extraneous sources of modern carbon retained in the samples. Research is currently focusing on the investigation of these issues and selected samples are in the process of being retreated with strong oxidising agents to clear contaminants prior to re-dating. Further to this, a full investigation of one profile with a long sequence is underway. High concentrations of

  1. Effect of Mo Content on Microstructure and Property of Low-Carbon Bainitic Steels

    Directory of Open Access Journals (Sweden)

    Haijiang Hu

    2016-07-01

    Full Text Available In this work, three low-carbon bainitic steels, with different Mo contents, were designed to investigate the effects of Mo addition on microstructure and mechanical properties. Two-step cooling, i.e., initial accelerated cooling and subsequent slow cooling, was used to obtain the desired bainite microstructure. The results show that the product of strength and elongation first increases and then shows no significant change with increasing Mo. Compared with Mo-free steel, bainite in the Mo-containing steel tends to have a lath-like morphology due to a decrease in the bainitic transformation temperature. More martensite transformation occurs with the increasing Mo, resulting in greater hardness of the steel. Both the strength and elongation of the steel can be enhanced by Mo addition; however, the elongation may decrease with a further increase in Mo. From a practical viewpoint, the content of Mo could be ~0.14 wt. % for the composition design of low-carbon bainitic steels in the present work. To be noted, an optimal scheme may need to consider other situations such as the role of sheet thickness, toughness behavior and so on, which could require changes in the chemistry. Nevertheless, these results provide a reference for the composition design and processing method of low-carbon bainitic steels.

  2. Topsoil organic carbon content of Europe, a new map based on a generalised additive model

    Science.gov (United States)

    de Brogniez, Delphine; Ballabio, Cristiano; Stevens, Antoine; Jones, Robert J. A.; Montanarella, Luca; van Wesemael, Bas

    2014-05-01

    There is an increasing demand for up-to-date spatially continuous organic carbon (OC) data for global environment and climatic modeling. Whilst the current map of topsoil organic carbon content for Europe (Jones et al., 2005) was produced by applying expert-knowledge based pedo-transfer rules on large soil mapping units, the aim of this study was to replace it by applying digital soil mapping techniques on the first European harmonised geo-referenced topsoil (0-20 cm) database, which arises from the LUCAS (land use/cover area frame statistical survey) survey. A generalized additive model (GAM) was calibrated on 85% of the dataset (ca. 17 000 soil samples) and a backward stepwise approach selected slope, land cover, temperature, net primary productivity, latitude and longitude as environmental covariates (500 m resolution). The validation of the model (applied on 15% of the dataset), gave an R2 of 0.27. We observed that most organic soils were under-predicted by the model and that soils of Scandinavia were also poorly predicted. The model showed an RMSE of 42 g kg-1 for mineral soils and of 287 g kg-1 for organic soils. The map of predicted OC content showed the lowest values in Mediterranean countries and in croplands across Europe, whereas highest OC content were predicted in wetlands, woodlands and in mountainous areas. The map of standard error of the OC model predictions showed high values in northern latitudes, wetlands, moors and heathlands, whereas low uncertainty was mostly found in croplands. A comparison of our results with the map of Jones et al. (2005) showed a general agreement on the prediction of mineral soils' OC content, most probably because the models use some common covariates, namely land cover and temperature. Our model however failed to predict values of OC content greater than 200 g kg-1, which we explain by the imposed unimodal distribution of our model, whose mean is tilted towards the majority of soils, which are mineral. Finally, average

  3. Novel porous carbon materials with ultrahigh nitrogen contents for selective CO 2 capture

    KAUST Repository

    Zhao, Yunfeng; Zhao, Lan; Yao, Kexin; Yang, Yang; Zhang, Qiang; Han, Yu

    2012-01-01

    Nitrogen-doped carbon materials were prepared by a nanocasting route using tri-continuous mesoporous silica IBN-9 as a hard template. Rationally choosing carbon precursors and carefully controlling activation conditions result in an optimized material denoted as IBN9-NC1-A, which possesses a very high nitrogen doping concentration (∼13 wt%) and a large surface area of 890 m 2 g -1 arising from micropores (<1 nm). It exhibits an excellent performance for CO 2 adsorption over a wide range of CO 2 pressures. Specifically, its equilibrium CO 2 adsorption capacity at 25 °C reaches up to 4.50 mmol g -1 at 1 bar and 10.53 mmol g -1 at 8 bar. In particular, it shows a much higher CO 2 uptake at low pressure (e.g. 1.75 mmol g -1 at 25 °C and 0.2 bar) than any reported carbon-based materials, owing to its unprecedented nitrogen doping level. The high nitrogen contents also give rise to significantly enhanced CO 2/N 2 selectivities (up to 42), which combined with the high adsorption capacities, make these new carbon materials promising sorbents for selective CO 2 capture from power plant flue gas and other relevant applications. © 2012 The Royal Society of Chemistry.

  4. Influence of the Mg-content on ESR-signals in synthetic calcium carbonate

    International Nuclear Information System (INIS)

    Barabas, M.; Bach, A.; Mudelsee, M.; Mangini, A.

    1989-01-01

    Carbonate crystals doped with various concentrations of Mg 2+ -ions have been grown by a gel-diffusion method. An increase of the Mg/Ca-ratio to more than about 1 caused a phase change in the crystal lattice from calcite to aragonite. The properties of the ESR-signals of the synthetic carbonates were studied and compared with natural marine carbonates. The following results were derived: (a) In the presence of Mg 2+ -ions the synthetic carbonates display the same ESR-signals as natural calcites of marine origin with similar properties (thermal stability, radiation sensitivity). (b) The saturation value of the signal at g=2.0006 in synthetic calcites was found to be strongly related with the Mg-content in the crystals. (c) The signal at g=2.0036 (axial symmetry) which is present in calcite was not influenced by the Mg-concentration. Its saturation value decreases when the crystal phase changed from calcite to aragonite and in complement the signal at g=2.0031 appeared. (d) The signals at g=2.0057 and g=2.0031 are most probably not of organic origin. (author)

  5. Mapping soil organic carbon content and composition across Australia to assess vulnerability to climate change

    Science.gov (United States)

    Viscarra Rossel, R. A.

    2015-12-01

    We can effectively monitor soil condition—and develop sound policies to offset the emissions of greenhouse gases—only with accurate data from which to define baselines. Currently, estimates of soil organic C for countries or continents are either unavailable or largely uncertain because they are derived from sparse data, with large gaps over many areas of the Earth. Here, we derive spatially explicit estimates, and their uncertainty, of the distribution and stock of organic C content and composition in the soil of Australia. The composition of soil organic C may be characterized by chemical separation or physical fractionation based on either particle size or particle density (Skjemstad et al., 2004; Gregorich et al., 2006; Kelleher&Simpson, 2006; Zimmermann et al., 2007). In Australia, for example, Skjemstad et al. (2004) used physical separation of soil samples into 50-2000 and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, giving the three OC pools, particulate organic carbon (POC), humic organic carbon (HOC) and resistant organic carbon (ROC; charcoal or char-carbon). We assembled and harmonized data from several sources to produce the most comprehensive set of data on the current stock of organic C in soil of the continent. Using them, we have produced a fine spatial resolution baseline map of organic C, POC, HOC and ROC at the continental scale. In this presentation I will describe how we made the maps and how we use them to assess the vulnerability of soil organic C to for instance climate change.

  6. The hydrogen and oxygen content of self-supporting carbon foils prepared by dc glow discharge in ethylene

    International Nuclear Information System (INIS)

    Tait, N.R.S.; Tolfree, D.W.L.; John, P.; Odeh, I.M.; Thomas, M.J.K.; Tricker, M.J.; Wilson, J.J.B.; England, J.B.A.; Newton, D.

    1980-01-01

    The hydrogen and oxygen content of self-supporting carbon films produced by dc glow discharge have been determined using a precise method involving the elastic scattering of 25 MeV α-particles. The number of carbon-hydrogen bonds has been determined for similar samples using infrared spectroscopy. The results are compared with those for samples made by the carbon arc process. Assuming that the glow discharge carbon contains graphitic regions surrounded by amorphous tetrahedrally bonded material to which hydrogen can attach, a simple estimate is made of the relative numbers of carbon atoms in the two forms. (orig.)

  7. Content of carbon monoxide in the tissues of rats intoxicated with carbon monoxide in various conditions of acute exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sokal, J.A.; Majka, J.; Palus, J.

    1984-12-01

    Tissue carbon monoxide (CO) content was investigated in rats severely intoxicated with CO under various exposure conditions: 1% CO for 4 min, 0.4% CO for 40 min and 0.12% CO for 12 h. Extravascular CO was determined in the heart and skeletal muscles immediately after termination of exposure, and carboxymyoglobin (MbCO) percent saturation was calculated. Total brain CO was estimated immediately after termination of exposure and after the time periods of restitution. After the same exposure conditions, MbCO percent saturation was higher in the heart than in skeletal muscle. In both types of muscle, saturation on myoglobin (Mb) with CO depended on blood carboxyhemoglobin (HbCO) level and not on the duration of exposure. The time course of CO elimination was the same for blood and brain, irrespective of CO exposure conditions. The results obtained showed that acute CO intoxication induced by long duration exposures did not involve CO accumulation in the tissues.

  8. Carbon content and C:N ratio of transparent exopolymeric particles (TEP) produced by bubbling exudates of diatoms

    DEFF Research Database (Denmark)

    Mari, Xavier

    1999-01-01

    The carbon content of transparent exopolymeric particles (TEP) was measured in the laboratory in particles produced by bubbling exudates of the diatom Thalassiosira weissflogii, grown under nitrogen non-limited conditions (N:P = 7). The carbon content of these particles (TEP-C) appears to vary...... a coastal area (Kattegat, Denmark), TEP carbon concentration in the surface mixed layer was on the order of 230 ± 150 µg C l-1. This is high relative to other sources of particulate organic carbon (e.g. phytoplankton) and depending on TEP turnover rates, suggests that TEP is an important pathway...... for dissolved organic carbon in coastal seas. The carbon to nitrogen ratio of TEP was measured from particles formed by bubbling exudates of the diatoms T. weissflogii, Skeletonema costatum, Chaetoceros neogracile and C. affinis. Each of these diatom species was grown under various N:P ratios, from N...

  9. Integrated carbon, sulfur, and nitrogen isotope chemostratigraphy of the Ediacaran Lantian Formation in South China: Spatial gradient, ocean redox oscillation, and fossil distribution.

    Science.gov (United States)

    Wang, W; Guan, C; Zhou, C; Peng, Y; Pratt, L M; Chen, X; Chen, L; Chen, Z; Yuan, X; Xiao, S

    2017-07-01

    The Ediacaran Doushantuo Formation in South China is a prime target for geobiological investigation because it offers opportunities to integrate chemostratigraphic and paleobiological data. Previous studies were mostly focused on successions in shallow-water shelf facies, but data from deep-water successions are needed to fully understand basinal redox structures. Here, we report δ 13 C carb , δ 13 C org , δ 34 S pyr , δ 34 S CAS , and δ 15 N sed data from a drill core of the fossiliferous Lantian Formation, which is a deep-water equivalent of the Doushantuo Formation. Our data confirm a large (>10‰) spatial gradient in δ 13 C carb in the lower Doushantuo/Lantian formations, but this gradient is probably due to the greater sensitivity of carbonate-poor deep-water sediments to isotopic mixing with 13 C-depleted carbonate cements. A pronounced negative δ 13 C carb excursion (EN3) in the upper Doushantuo/Lantian formations, however, is spatially consistent and may be an equivalent of the Shuram excursion. δ 34 S pyr is more negative in deeper-water facies than in shallow-water facies, particularly in the lower Doushantuo/Lantian formations, and this spatial pattern is interpreted as evidence for ocean redox stratification: Pyrite precipitated in euxinic deep waters has lower δ 34 S pyr than that formed within shallow-water sediments. The Lantian Formation was probably deposited in oscillating oxic and euxinic conditions. Euxinic black shales have higher TOC and TN contents, but lower δ 34 S pyr and δ 15 N sed values. In euxinic environments, pyrite was predominantly formed in the water column and organic nitrogen was predominantly derived from nitrogen fixation or NH 4 + assimilation because of quantitative denitrification, resulting in lower δ 34 S pyr and δ 15 N sed values. Benthic macroalgae and putative animals occur exclusively in euxinic black shales. If preserved in situ, these organisms must have lived in brief oxic episodes punctuating largely

  10. Confident methods for the evaluation of the hydrogen content in nanoporous carbon microfibers

    Science.gov (United States)

    Culebras, Mario; Madroñero, Antonio; Cantarero, Andres; Amo, José Maria; Domingo, Concepción; López, Antonio

    2012-10-01

    Nanoporous carbon microfibers were grown by chemical vapor deposition in the vapor-liquid solid mode using different fluid hydrocarbons as precursors in different proportions. The as-grown samples were further treated in argon and hydrogen atmospheres at different pressure conditions and annealed at several temperatures in order to deduce the best conditions for the incorporation and re-incorporation of hydrogen into the microfibers through the nanopores. Since there are some discrepancies in the results on the hydrogen content obtained under vacuum conditions, in this work, we have measured the hydrogen content in the microfibers using several analytical methods in ambient conditions: surface tension, mass density, and Raman measurements. A discussion on the validity of the results obtained through the correlation between them is the purpose of the present work.

  11. Effect of Carbon Content on the Microstructure and Mechanical Properties of NbC-Ni Based Cermets

    Directory of Open Access Journals (Sweden)

    Shuigen Huang

    2018-03-01

    Full Text Available The aim of this work was to correlate the overall carbon content in NbC-Ni, NbC-Ni-VC and NbC-Ni-Mo starting powders with the resulting microstructure, hardness, and fracture toughness of Ni-bonded NbC cermets. A series of NbC-Ni, NbC-Ni-VC and NbC-Ni-Mo cermets with different carbon content were prepared by conventional liquid phase sintering for 1 h at 1420 °C in vacuum. Microstructural analysis of the fully densified cermets was performed by electron probe microanalysis (EPMA to assess the effect of carbon and VC or Mo additions on the NbC grain growth and morphology. A decreased carbon content in the starting powder mixtures resulted in increased dissolution of Nb, V, and Mo in the Ni binder and a decreased C/Nb ratio in the NbC based carbide phase. The Vickers hardness (HV30 and Palmqvist indentation toughness were found to decrease significantly with an increasing carbon content in the Mo-free cermets, whereas an antagonistic correlation between hardness and toughness was obtained as a function of the Mo-content in Mo-modified NbC cermets. To obtain optimized mechanical properties, methods to control the total carbon content of NbC-Ni mixtures were proposed and the prepared cermets were investigated in detail.

  12. Determination of local carbon content in austenite during intercritical annealing of dual phase steels by PEELS analysis

    International Nuclear Information System (INIS)

    Garcia-Junceda, A.; Caballero, F.G.; Capdevila, C.; Garcia de Andres, C.

    2007-01-01

    Parallel electron energy loss spectroscopy has allowed to analyse and quantify local variations in the carbon concentration of austenite islands transformed during the intercritical annealing treatment of commercial dual-phase steels. These changes in the carbon content of different austenite regions are responsible for the different volume fractions of tempered martensite, martensite and retained austenite obtained after intercritical annealing and overaging treatment. This technique reveals how carbon distribution in austenite evolves as the transformation process advances

  13. Where do fossil fuel carbon dioxide emissions from California go? An analysis based on radiocarbon observations and an atmospheric transport model

    Energy Technology Data Exchange (ETDEWEB)

    Riley, W.J.; Hsueh, D.Y.; Randerson, J.T.; Fischer, M.L.; Hatch, J.G.; Pataki, D.E.; Wang, W.; Goulden, M.L.

    2008-05-01

    Characterizing flow patterns and mixing of fossil fuel-derived CO{sub 2} is important for effectively using atmospheric measurements to constrain emissions inventories. Here we used measurements and a model of atmospheric radiocarbon ({sup 14}C) to investigate the distribution and fluxes of atmospheric fossil fuel CO{sub 2} across the state of California. We sampled {sup 14}C in annual C{sub 3} grasses at 128 sites and used these measurements to test a regional model that simulated anthropogenic and ecosystem CO{sub 2} fluxes, transport in the atmosphere, and the resulting {sup 14}C of annual grasses ({Delta}{sub g}). Average measured {Delta}{sub g} in Los Angeles, San Francisco, the Central Valley, and the North Coast were 27.7 {+-} 20.0, 44.0 {+-} 10.9, 48.7 {+-} 1.9, and 59.9 {+-} 2.5{per_thousand}, respectively, during the 2004-2005 growing season. Model predictions reproduced regional patterns reasonably well, with estimates of 27.6 {+-} 2.4, 39.4 {+-} 3.9, 46.8 {+-} 3.0, and 59.3 {+-} 0.2{per_thousand} for these same regions and corresponding to fossil fuel CO{sub 2} mixing ratios (Cf) of 13.7, 6.1, 4.8, and 0.3 ppm. {Delta}{sub g} spatial heterogeneity in Los Angeles and San Francisco was higher in the measurements than in the predictions, probably from insufficient spatial resolution in the fossil fuel inventories (e.g., freeways are not explicitly included) and transport (e.g., within valleys). We used the model to predict monthly and annual transport patterns of fossil fuel-derived CO{sub 2} within and out of California. Fossil fuel CO{sub 2} emitted in Los Angeles and San Francisco was predicted to move into the Central Valley, raising Cf above that expected from local emissions alone. Annually, about 21, 39, 35, and 5% of fossil fuel emissions leave the California airspace to the north, east, south, and west, respectively, with large seasonal variations in the proportions. Positive correlations between westward fluxes and Santa Ana wind conditions were

  14. Filterability of corrosion products formed between carbon steel and water. Influence of temperature and oxygen content

    International Nuclear Information System (INIS)

    Kelen, T.; Falk, I.

    1975-09-01

    A laboratory investigation has been made for the purpose of studying the influence of temperature and oxygen content on the filterability of corrosion products formed between carbon-steel and water. The experiments were performed in a high temperature loop where the water is initially heated in a pre-heater, then cooled and finally filtered. The corrosion products were transferred to thewater from a carbon-steel surface that had previously been neutron activated and the amount of iron present was determined from measurements of the γ-radiation emitted by Fe-59. Filterability was then computed as the ratio between the total amount of iron in the water phase and the amount of iron retained on the filter. The investigation covers a series of experiments at filtering temperatures of 20, 90 and 160 dec G, pre-heater temperatures up to 300 deg C and oxygen contents of 10 and 300 ppb O 2 . In addition the extent of iron deposition in the pre-heater and heat regulator has been determined after each series of experiments. Filterability exhibited a pronounced dependence upon both the filter and pre-heater temperatures and also upon the oxygen content. Among the conclusions to which the results lead is the observation that a strict comparison of filterability values for the fraction of corrosion products in cooled water samples is impossible when these are taken from 1) different sections of a high temperature system 2) a single sampling point while the system is being run up 3) two separate systems (e.g. steam boilers) operated at different temperatures 4) two separate systems operated at different oxygen contents. It accordingly appears advizable to restrict the use of cold-filtered samples from conventional steam-raising plants to the comparison of values relating to a single sampling point under constant operating conditions. (author)

  15. The efficiency of different types of wood charcoal on increasing carbon content on surfaces of low carbon steel in the pack carburizing process

    Directory of Open Access Journals (Sweden)

    Narongsak Thammachot

    2014-09-01

    Full Text Available The purpose of this research is to compare the efficiency of five types of wood charcoal, eucalyptus, coconut shell, tamarind, bamboo and cassava root in increasing carbon content on surfaces of low carbon steel by the pack carburizing process. The experiment for pack carburized low carbon steel (grade AISI 1020 was conducted by using the different wood charcoals as carburizers, mixed with 10% limestone (by weight as the energizer. The carburizing temperature of 950°C, and carburizing times of 2, 4 and 6 hours were used in the experiment. After grinding, the specimens in each case were checked for carbon content by optical emission spectroscopy. Micro-Vickers hardness testing and microstructure inspections were carried out. The results of the experiment showed that the efficiency of eucalyptus charcoal as the carburizer (for increasing carbon content on surfaces of low carbon steel was higher than that of tamarind, cassava root, coconut shell and bamboo charcoals. The averages for carbon content were: 1.16, 1.06, 0.97, 0.83 and 0.77% respectively.

  16. Beyond clay - using selective extractions to improve predictions of soil carbon content

    Science.gov (United States)

    Rasmussen, C.; Berhe, A. A.; Blankinship, J. C.; Crow, S. E.; Druhan, J. L.; Heckman, K. A.; Keiluweit, M.; Lawrence, C. R.; Marin-Spiotta, E.; Plante, A. F.; Schaedel, C.; Schimel, J.; Sierra, C. A.; Thompson, A.; Wagai, R.; Wieder, W. R.

    2016-12-01

    A central component of modern soil carbon (C) models is the use of clay content to scale the relative partitioning of decomposing plant material to respiration and mineral stabilized soil C. However, numerous pedon to plot scale studies indicate that other soil mineral parameters, such as Fe- or Al-oxyhydroxide content and specific surface area, may be more effective than clay alone for predicting soil C content and stabilization. Here we directly address the following question: Are there soil physicochemical parameters that represent mineral C association and soil C content that can replace or be used in conjunction with clay content as scalars in soil C models. We explored the relationship of soil C content to a number of soil physicochemical and physiographic parameters using the National Cooperative Soil Survey database that contains horizon level data for > 62,000 pedons spanning global ecoregions and geographic areas. The data indicated significant variation in the degree of correlation among soil C, clay and Fe-/Al-oxyhydroxides with increasing moisture variability. Specifically, dry, water-limited systems (PET/MAP > 1) presented strong positive correlations between clay and soil C, that decreased significantly to little or no correlation in wet, energy-limited systems (PET/MAP soil C to oxalate extractable Al+Fe increased significantly with increasing moisture availability. This pattern was particularly well expressed for subsurface B horizons. Multivariate analyses indicated similar patterns, with clear climate and ecosystem level variation in the degree of correlation among soil C and soil physicochemical properties. The results indicate a need to modify current soil C models to incorporate additional C partitioning parameters that better account for climate and ecoregion variability in C stabilization mechanisms.

  17. Element fractionation by sequential extraction in a soil with high carbonate content

    International Nuclear Information System (INIS)

    Sulkowski, Margareta; Hirner, Alfred V.

    2006-01-01

    The influence of carbonate and other buffering substances in soils on the results of a 3-step sequential extraction procedure (BCR) used for metal fractionation was investigated. Deviating from the original extraction scheme, where the extracts are analysed only for a limited number of metals, almost all elements in the soils were quantified by X-ray fluorescence spectroscopy, in the initial samples as well as in the residues of all extraction steps. Additionally, the mineral contents were determined by X-ray diffractometry. Using this methodology, it was possible to correlate changes in soil composition caused by the extraction procedure with the release of elements. Furthermore, the pH values of all extracts were monitored, and certain extraction steps were repeated until no significant pH-rise occurred. A soil with high dolomite content (27%) and a carbonate free soil were extracted. Applying the original BCR-sequence to the calcareous soil, carbonate was found in the residues of the first two steps and extract pH-values rose by around two units in the first and second step, caused mainly by carbonate dissolution. This led to wrong assignment of the carbonate elements Ca, Mg, Sr, Ba, and also to decreased desorption and increased re-adsorption of ions in those steps. After repetition of the acetic acid step until extract pH remained low, the carbonate was completely destroyed and the distributions of the elements Ca, Mg, Sr, Ba as well as those of Co, Ni, Cu, Zn and Pb were found to be quite different to those determined in the original extraction. Furthermore, it could be shown that the effectiveness of the reduction process in step two was reduced by increasing pH: Fe oxides were not significantly attacked by the repeated acetic acid treatments, but a 10-fold amount of Fe was mobilized by hydroxylamine hydrochloride after complete carbonate destruction. On the other hand, only small amounts of Fe were released anyway. Even repeated reduction steps did not

  18. Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO{sub 3}@C composites as anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Fuqiang [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Fang, Guoqing [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Changzhou Institute of Energy Storage Materials and Devices, Changzhou 213000 (China); Zhang, Ruixue [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Xu, Yanhui; Zheng, Junwei [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China); Li, Decheng, E-mail: lidecheng@suda.edu.cn [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China)

    2014-08-30

    Highlights: • The thickness of carbon coating layers can be successfully controlled through varying molar concentration of aqueous glucose solution. • Coating carbon thickness and carbon content are two important factors on the electrochemical performances of CoSnO3@C. • CoSnO{sub 3}@C under optimized conditions exhibits the optimal balance between the volume buffering effect and reversible capacity. • As-prepared CoSnO{sub 3}@C under optimized conditions shows excellent electrochemical performances, whose reversible capacity could reach 491 mA h g{sup −1} after 100 cycles. - Abstract: A series of core–shell carbon coated amorphous CoSnO{sub 3} (CoSnO{sub 3}@C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge–discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO{sub 3}@C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g{sup −1} after 100 cycles.

  19. The Effect of Paved Roads on Organic Carbon Content of Soil in Taham Dam Basin

    Directory of Open Access Journals (Sweden)

    Mazyar Peyda

    2016-09-01

    Full Text Available Background: Contamination of water and soil through non-point sources such as road runoff causes environmental concern. The aim of this study is to determine the effect of Zanjan – Chavarzagh road on the total organic carbon (TOC content of sediments in tributaries and the river that lead to Taham Lake. Methods: In tributaries and the river 69 soil and sediment samples were taken and the Total organic carbon (TOC was measured according to Walkely-Black method. Also, Taham Dam Basin area and its hydrologic properties were calculated by Global Information System (GIS software. Results: Results showed that, TOC concentration has a significant negative relationship with the distance from the lake. TOC in soil samples taken from hillside of the road had significantly lower mean and median concentration ( median= 3262 , mean = 4083 ± 3461 mg/kg than the valley side ( median = 5324 , mean = 6178 ± 3980 mg/kg. The check dams across the tributaries and the river have not been effective in the reduction of TOC in sediments. Conclusion: Roads in the Taham Dam Basin, increases TOC content of soil and sediments in Taham dam basin. TOC moves toward Taham dam lake.

  20. Ameliorated Austenite Carbon Content Control in Austempered Ductile Irons by Support Vector Regression

    Directory of Open Access Journals (Sweden)

    Chan-Yun Yang

    2013-01-01

    Full Text Available Austempered ductile iron has emerged as a notable material in several engineering fields, including marine applications. The initial austenite carbon content after austenization transform but before austempering process for generating bainite matrix proved critical in controlling the resulted microstructure and thus mechanical properties. In this paper, support vector regression is employed in order to establish a relationship between the initial carbon concentration in the austenite with austenization temperature and alloy contents, thereby exercising improved control in the mechanical properties of the austempered ductile irons. Particularly, the paper emphasizes a methodology tailored to deal with a limited amount of available data with intrinsically contracted and skewed distribution. The collected information from a variety of data sources presents another challenge of highly uncertain variance. The authors present a hybrid model consisting of a procedure of a histogram equalizer and a procedure of a support-vector-machine (SVM- based regression to gain a more robust relationship to respond to the challenges. The results show greatly improved accuracy of the proposed model in comparison to two former established methodologies. The sum squared error of the present model is less than one fifth of that of the two previous models.

  1. Biomass Carbon Content in Schima- Castanopsis Forest of Midhills of Nepal: A Case Study from Jaisikuna Community Forest, Kaski

    Directory of Open Access Journals (Sweden)

    Sushma Tripathi

    2018-01-01

    Full Text Available Community forests of Nepal’s midhills have high potentiality to sequester carbon. This paper tries to analyze the biomass carbon stock in Schima-Castanopsis forest of Jaisikuna community forests of Kaski district, Nepal. Forest area was divided into two blocks and 18 sample plots (9 in each block which were laid randomly. Diameter at Breast Height (DBH and height of trees (DBH≥5cm were measured using the DBH tape and clinometer. Leaf litter, herbs, grasses and seedlings were collected from 1*1m2 plot and fresh weight was taken. For calculating carbon biomass is multiplied by default value 0.47. The AGTB carbon content of Chilaune, Katus and other species were found 19.56 t/ha, 18.66 t/ha and 3.59 t/ha respectively. The AGTB of Chilaune dominated, Katus dominated and whole forest was found 43.78 t/ha, 39.83 t/ha and 41.81 t/ha respectively. Carbon content at leaf litter, herbs, grasses and seedlings was found 2.73 t/ha. Below ground biomass carbon at whole forest was found 6.27 t/ha. Total biomass and carbon of the forest was found 108.09 t/ha and 50.80 t/ha respectively. Difference in biomass and carbon content at Chilaune dominated block and Katus dominated block was found insignificant. This study record very low biomass carbon content than average of Nepal's forest but this variation in carbon stock is not necessarily due to dominant species present in the forest. Carbon estimation at forest of different elevation, aspect and location are recommended for further research. International Journal of EnvironmentVolume-6, Issue-4, Sep-Nov 2017, page: 72-84

  2. Primary Nutritional Content of Bio-Flocs Cultured with Different Organic Carbon Sources and Salinity

    Directory of Open Access Journals (Sweden)

    JULIE EKASARI

    2010-09-01

    Full Text Available Application of bio-flocs technology (BFT in aquaculture offers a solution to avoid environmental impact of high nutrient discharges and to reduce the use of artificial feed. In BFT, excess of nutrients in aquaculture systems are converted into microbial biomass, which can be consumed by the cultured animals as a food source. In this experiment, upconcentrated pond water obtained from the drum filter of a freshwater tilapia farm was used for bio-flocs reactors. Two carbon sources, sugar and glycerol, were used as the first variable, and two different levels of salinity, 0 and 30 ppt, were used as the second variable. Bio-flocs with glycerol as a carbon source had higher total n-6 PUFAs (19.1 ± 2.1 and 22.3 ± 8.6 mg/g DW at 0 and 30 ppt, respectively than that of glucose (4.0 ± 0.1 and 12.6 ± 2.5 mg/g DW at 0 and 30 ppt. However, there was no effect of carbon source or salinity on crude protein, lipid, and total n-3 PUFAs contents of the bio-flocs.

  3. Growth Mechanism and Origin of High s p3 Content in Tetrahedral Amorphous Carbon

    Science.gov (United States)

    Caro, Miguel A.; Deringer, Volker L.; Koskinen, Jari; Laurila, Tomi; Csányi, Gábor

    2018-04-01

    We study the deposition of tetrahedral amorphous carbon (ta-C) films from molecular dynamics simulations based on a machine-learned interatomic potential trained from density-functional theory data. For the first time, the high s p3 fractions in excess of 85% observed experimentally are reproduced by means of computational simulation, and the deposition energy dependence of the film's characteristics is also accurately described. High confidence in the potential and direct access to the atomic interactions allow us to infer the microscopic growth mechanism in this material. While the widespread view is that ta-C grows by "subplantation," we show that the so-called "peening" model is actually the dominant mechanism responsible for the high s p3 content. We show that pressure waves lead to bond rearrangement away from the impact site of the incident ion, and high s p3 fractions arise from a delicate balance of transitions between three- and fourfold coordinated carbon atoms. These results open the door for a microscopic understanding of carbon nanostructure formation with an unprecedented level of predictive power.

  4. Desorption behaviors of BDE-28 and BDE-47 from natural soils with different organic carbon contents

    International Nuclear Information System (INIS)

    Liu Wenxin; Cheng Fangfang; Li Weibo; Xing Baoshan; Tao Shu

    2012-01-01

    Desorption kinetic and isothermal characteristics of BDE-28 and BDE-47 were investigated using natural soils with different organic carbon fractions. The results indicated that a two-compartment first-order model with dominant contribution of slow desorption could adequately describe the released kinetics of studied PBDEs. Desorption isotherms of different samples could be fitted well by linear distribution model or nonlinear Freundlich model. Moreover, most desorption procedures roughly exhibited hysteresis with respect to preceding sorption ones. At the statistically significant level of 0.05 or 0.1, total organic carbon content (f OC ) exhibited significant correlations with the fitted parameters by the isothermal models. The correlations of f OC and SOM fractions (e.g., fulvic acid and humin) with the single point desorption coefficients at lower aqueous concentrations of studied PBDEs were significant; while at higher aqueous concentrations, the relationships were less significant or insignificant. Our findings may facilitate a comprehensive understanding on behaviors of PBDEs in soil systems. - Highlights: ► A two-compartment first-order kinetic model for the PBDEs studied was established. ► Isotherm was fitted well by a linear distribution or a nonlinear Freundlich model. ► Desorption commonly exhibited somewhat hysteresis relative to sorption. ► Soil organic carbon fractions showed close correlations with the model parameters. - Two-compartment first-order model, and linear distribution model or nonlinear Freundlich model could well elucidate desorption kinetics and isotherms of PBDEs in natural soils, respectively.

  5. Effect of carbon content on the microstructure and mechanical properties of superfine Ti(C, N)-based cermets

    International Nuclear Information System (INIS)

    Liu Ning; Liu Xuesong; Zhang Xiaobo; Zhu Longwei

    2008-01-01

    As a new kind of tool materials which appeared in the seventies last century, the Ti (C, N)-based cermets have been widely used in recent years due to many of its good properties. The microstructure of Ti(C, N)-based cermets with various carbon content were studied using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). Vickers hardness and transverse rupture strength (TRS) were also measured. An increased carbon content resulted in the finer grain size, decreased solution strength of tungsten and molybdenum in the binder phase, and a higher volume fraction of heavy (Ti, Mo, W)(C,N) cores. If the addition of carbon content is too little or too much, the phase composition of material will deviate from the normal dual phase section and lead to the formation of the third phase: η-phase if the carbon content is too low or dissociative carbon if the carbon content is too high. And the formation of the third phase will remarkably deteriorate the mechanical properties of cermets

  6. Highly ordered macroporous woody biochar with ultra-high carbon content as supercapacitor electrodes

    International Nuclear Information System (INIS)

    Jiang, Junhua; Zhang, Lei; Wang, Xinying; Holm, Nancy; Rajagopalan, Kishore; Chen, Fanglin; Ma, Shuguo

    2013-01-01

    Woody biochar monolith with ultra-high carbon content and highly ordered macropores has been prepared via one-pot pyrolysis and carbonization of red cedar wood at 750 °C without the need of post-treatment. Energy-dispersive spectroscope (EDX) and scanning electron microscope (SEM) studies show that the original biochar has a carbon content of 98 wt% with oxygen as the only detectable impurity and highly ordered macroporous texture characterized by alternating regular macroporous regions and narrow porous regions. Moreover, the hierarchically porous biochar monolith has a high BET specific surface area of approximately 400 m 2 g −1 . We have studied the monolith material as supercapacitor electrodes under acidic environment using electrochemical and surface characterization techniques. Electrochemical measurements show that the original biochar electrodes have a potential window of about 1.3 V and exhibit typical rectangular-shape voltammetric responses and fast charging–discharging behavior with a gravimetric capacitance of about 14 F g −1 . Simple activation of biochar in diluted nitric acid at room temperature leads to 7 times increase in the capacitance (115 F g −1 ). Because the HNO 3 -activation slightly decreases rather than increases the BET surface area of the biochar, an increase in the coverage of surface oxygen groups is the most likely origin of the substantial capacitance improvement. This is supported by EDX, X-ray photoelectron spectroscopy (XPS), and Raman measurements. Preliminary life-time studies show that biochar supercapacitors using the original and HNO 3 -activated electrodes are stable over 5000 cycles without performance decays. These facts indicate that the use of woody biochar is promising for its low cost and it can be a good performance electrode with low environmental impacts for supercapacitor applications

  7. Stable carbon isotope composition of organic material and carbonate in sediment of a swamp and lakes in Honshu island, Japan

    International Nuclear Information System (INIS)

    Ishizuka, Toshio

    1978-01-01

    Recent sediments from a swamp and lakes in Honshu were analyzed for organic carbon and carbonate contents, and stable isotope ratios of carbon in the organic materials and carbonate. delta C 13 values of the carbonate tend to be distinctly larger than those of organic carbon in reducing condition as natural gas field, whereas in oxidizing SO 4 -reducing conditions, they are slightly larger than those of organic carbon within the limited range of a few per mil. Carbon isotopic compositions of organic carbon in sediment of the swamp, Obuchi-numa, were analyzed and compared with habitat analysis of associated fossil diatoms. deltaC 13 values of organic carbon in the sediment vary in correlation with the species abundance in habitat of the associated fossil diatoms, ranging from fresh-water (-0.0282) to coastal marine (-0.0236) via brackish. (auth.)

  8. OKLO: fossil reactors

    International Nuclear Information System (INIS)

    Naudet, R.

    Events leading up to the discovery during the summer of 1972 of the Oklo fossil reactor in Gabon and its subsequent exploration are reviewed. Results of studies are summarized; future investigations are outlined

  9. Exploring the potential impact of implementing carbon capture technologies in fossil fuel power plants on regional European water stress index levels

    NARCIS (Netherlands)

    Schakel, W.B.; Pfister, Stephan; Ramirez, C.A.

    Equipping power plants with carbon capture technology can affect cooling demand and water use. This study has explored the potential impact of large scale deployment of power plants with carbon capture technologies on future regional water stress in Europe. A database including 458 of European

  10. Influence of alkali, silicate, and sulfate content of carbonated concrete pore solution on mild steel corrosion behavior

    International Nuclear Information System (INIS)

    L'Hostis, V.; Huet, B.; Tricheux, L.; Idrissi, H.

    2010-01-01

    The increase in the rebar corrosion rate due to the concrete carbonation is the major cause of reinforced concrete degradation. The aim of this study was to investigate the corrosion behavior of mild steel rebars in simulated carbonated concrete solution. For this purpose, thermodynamic calculations, electrochemical techniques, gravimetric measurements, and surface analyses were used. Thermodynamic investigations of the nature of the interstitial solution provides an estimation of the influence of sulfate (SO 4 2- ) and alkali (Na + , K + ) content on carbonate alkalinity of the CO 2 /H 2 O open system (pCO 2 =0. 3 mbar). in this system, calcium-silicate hydrates (C-S-H) remain thermodynamically unstable and amorphous silica controls silicate aqueous content at 100 ppm. Electrochemical results highlight a decrease in the corrosion rate with increasing carbonate alkalinity and the introduction of silicate. The introduction of sulfate at fixed carbonate alkalinity shows a dual effect: at high carbonate alkalinity, the corrosion rate is increased whereas at low carbonate alkalinity, corrosion rate is decreased. Those results are supported by surface analysis. Authors conclude that silicate and sulfate release from cement hydrates and fixation of alkali on carbonated hydrates are key parameters to estimate mild steel corrosion in carbonated concrete. (authors)

  11. Clay content drives carbon stocks in soils under a plantation of Eucalyptus saligna Labill. in southern Brazil

    Directory of Open Access Journals (Sweden)

    Tanise Luisa Sausen

    2014-06-01

    Full Text Available Soil carbon accumulation is largely dependent on net primary productivity. To our knowledge, there have been no studies investigating the dynamics of carbon accumulation in weathered subtropical soils, especially in managed eucalyptus plantations. We quantified the seasonal input of leaf litter, the leaf decomposition rate and soil carbon stocks in an commercial plantation of Eucalyptus saligna Labill. in southern Brazil. Our goal was to evaluate, through multiple linear regression, the influence that certain chemical characteristics of litter, as well as chemical and physical characteristics of soil, have on carbon accumulation in soil organic matter fractions. Variables related to the chemical composition of litter were not associated with the soil carbon stock in the particulate and mineral fractions. However, certain soil characteristics were significantly associated with the carbon stock in both fractions. The concentrations of nutrients associated with plant growth and productivity, such as phosphorus, sulfur, copper and zinc, were associated with variations in the labile carbon pool (particulate fraction. Clay content was strongly associated with the carbon stock in the mineral fraction. The carbon accumulation and stabilization in weathered subtropical Ultisol seems to be mainly associated with the intrinsic characteristics of the soil, particularly clay content, rather than with the quantity, chemical composition or decomposition rate of the litter.

  12. The European carbon tax: an assessment of the European Commission's proposals

    International Nuclear Information System (INIS)

    Pearson, M.; Smith, Stephen.

    1991-12-01

    After a lengthy internal debate within the European Commission, the Environment Commissioner announced the broad structure of the Commission's proposals for a European carbon tax towards the end of September. The proposed tax would be a combination of a tax on the carbon content of fossil fuels, and a tax on all non-renewable forms of energy. Thus, fossil fuels such as gas, coal and oil would bear a tax comprising two components, one related to their carbon content, the other related to their energy content. Non-renewable forms of energy other than fossil fuels (mainly nuclear power) would be subject to the energy-related part of the tax, but would not bear the carbon component. Overall, the two components would be combined in equal proportions, in the sense that half of the tax on a typical barrel of oil would be related to the carbon component and half to the energy component. (author)

  13. Using LUCAS topsoil database to estimate soil organic carbon content in local spectral libraries

    Science.gov (United States)

    Castaldi, Fabio; van Wesemael, Bas; Chabrillat, Sabine; Chartin, Caroline

    2017-04-01

    The quantification of the soil organic carbon (SOC) content over large areas is mandatory to obtain accurate soil characterization and classification, which can improve site specific management at local or regional scale exploiting the strong relationship between SOC and crop growth. The estimation of the SOC is not only important for agricultural purposes: in recent years, the increasing attention towards global warming highlighted the crucial role of the soil in the global carbon cycle. In this context, soil spectroscopy is a well consolidated and widespread method to estimate soil variables exploiting the interaction between chromophores and electromagnetic radiation. The importance of spectroscopy in soil science is reflected by the increasing number of large soil spectral libraries collected in the world. These large libraries contain soil samples derived from a consistent number of pedological regions and thus from different parent material and soil types; this heterogeneity entails, in turn, a large variability in terms of mineralogical and organic composition. In the light of the huge variability of the spectral responses to SOC content and composition, a rigorous classification process is necessary to subset large spectral libraries and to avoid the calibration of global models failing to predict local variation in SOC content. In this regard, this study proposes a method to subset the European LUCAS topsoil database into soil classes using a clustering analysis based on a large number of soil properties. The LUCAS database was chosen to apply a standardized multivariate calibration approach valid for large areas without the need for extensive field and laboratory work for calibration of local models. Seven soil classes were detected by the clustering analyses and the samples belonging to each class were used to calibrate specific partial least square regression (PLSR) models to estimate SOC content of three local libraries collected in Belgium (Loam belt

  14. How do changes in bulk soil organic carbon content affect carbon concentrations in individual soil particle fractions?

    Science.gov (United States)

    Yang, X. M.; Drury, C. F.; Reynolds, W. D.; Yang, J. Y.

    2016-06-01

    We test the common assumption that organic carbon (OC) storage occurs on sand-sized soil particles only after the OC storage capacity on silt- and clay-sized particles is saturated. Soil samples from a Brookston clay loam in Southwestern Ontario were analysed for the OC concentrations in bulk soil, and on the clay (<2 μm), silt (2-53 μm) and sand (53-2000 μm) particle size fractions. The OC concentrations in bulk soil ranged from 4.7 to 70.8 g C kg-1 soil. The OC concentrations on all three particle size fractions were significantly related to the OC concentration of bulk soil. However, OC concentration increased slowly toward an apparent maximum on silt and clay, but this maximum was far greater than the maximum predicted by established C sequestration models. In addition, significant increases in OC associated with sand occurred when the bulk soil OC concentration exceeded 30 g C kg-1, but this increase occurred when the OC concentration on silt + clay was still far below the predicted storage capacity for silt and clay fractions. Since the OC concentrations in all fractions of Brookston clay loam soil continued to increase with increasing C (bulk soil OC content) input, we concluded that the concept of OC storage capacity requires further investigation.

  15. Determination of Elements and Carbon Content of Stainless Steel Welded Pipeline

    Directory of Open Access Journals (Sweden)

    Pavel Hudeček

    2016-01-01

    Full Text Available Find out defects or problems of welds are not so simple from time to time. Specially, if weld has been made in rough environmental conditions like high temperature, dusty wind and humidity. It is important to assure have good conditions to realize basic step of welding. For welding, have been used welding procedures specification and procedure qualification record. However, difficult conditions, documentations rightness or human errors are always here. Common weld defects like cracks, porosity, lack of penetration and distortion can compromise the strength of the base metal, as well as the integrity of the weld. According of site inspection, there were suspicion of inclusions, leaker or segregation in root of weld. Surface treatment after welding and keep the intervals between single welds to not overheat the pipes. To recognize those suspicions, mechanical testing around weld joint, determination of carbon content and inductively coupled plasma atomic emission spectroscopy will be done.

  16. Multi-component EPR spectra of coals with different carbon content

    Energy Technology Data Exchange (ETDEWEB)

    Pilawa, B.; Wieckowski, A.B.; Pietrzak, R.; Wachowska, H. [Polish Academy of Science, Gliwice (Poland). Inst. for Coal Chemistry

    2005-08-01

    EPR spectra of lignite 'Mequinenza' (Spain) (62.3 wt% C) and Polish orthocoking coal (87.8 wt% C) were compared. The spectra were superpositions of broad Gaussian, broad Lorentzian 1, and narrow Lorentzian 3 lines. Concentration of paramagnetic centers - mainly delocalized pi electrons responsible for narrow Lorentzian 3 lines increases with increase in carbon content in coal. Coal units with slow and fast spin-lattice relaxation processes exist in the two studied samples. Slow spin-lattice interactions occur in simple aromatic coal units with broad Gaussian and Lorentzian 1 lines. Fast spin-lattice relaxation processes are characteristic of large aromatic units with narrow Lorentzian 3 lines.

  17. Tritium- and carbon-14-contents of wines of different vintage from the northern and southern hemisphere

    International Nuclear Information System (INIS)

    Fischer, E.; Mueller, H.

    1980-01-01

    The carbon-14 and tritium radioactivity contents of up to 19 vintages of German and Southafrican wines were compared. A similar large dependence of the 14 C- and of the 3 H-activity in the German wine on the nuclear weapon tests of the years 1962/63 was found out. The radioactivity level is also 1977/78 still essentially higher than before 1950. The Southafrican wines have been influenced considerably less by nuclear explosions. The highest 3 H-values were found in the vintage 1963 of the German wine with 5910 pCi/litre and in the vintage 1964 of the Southafrican wine with 510 pCi/litre. (orig.) [de

  18. Modelling the influence of carbon content on material behavior during forging

    Science.gov (United States)

    Korpała, G.; Ullmann, M.; Graf, M.; Wester, H.; Bouguecha, A.; Awiszus, B.; Behrens, B.-A.; Kawalla, R.

    2017-10-01

    Nowadays the design of single process steps and even of whole process chains is realized by the use of numerical simulation, in particular finite element (FE) based methods. A detailed numerical simulation of hot forging processes requires realistic models, which consider the relevant material-specific parameters to characterize the material behavior, the surface phenomena, the dies as well as models for the machine kinematic. This data exists partial for several materials, but general information on steel groups depending on alloying elements are not available. In order to generate the scientific input data regarding to material modelling, it is necessary to take into account the mathematical functions for deformation behavior as well as recrystallization kinetic, which depends alloying elements, initial microstructure and reheating mode. Besides the material flow characterization, a detailed description of surface changes caused by oxide scale is gaining in importance, as these phenomena affect the material flow and the component quality. Experiments to investigate the influence of only one chemical element on the oxide scale kinetic and the inner structure at high temperatures are still not available. Most data concerning these characteristics is provided for the steel grade C45, so this steel will be used as basis for the tests. In order to identify the effect of the carbon content on the material and oxidation behavior, the steel grades C15 and C60 will be investigated. This paper gives first approaches with regard to the influence of the carbon content on the oxide scale kinetic and the flow stresses combined with the initial microstructure.

  19. Electrical properties of multiphase composites based on carbon nanotubes and an optimized clay content

    Science.gov (United States)

    Egiziano, Luigi; Lamberti, Patrizia; Spinelli, Giovanni; Tucci, Vincenzo; Guadagno, Liberata; Vertuccio, Luigi

    2016-05-01

    The experimental results concerning the characterization of a multiphase nanocomposite systems based on epoxy matrix, loaded with different amount of multi-walled carbon nanotubes (MWCNTs) and an optimized Hydrotalcite (HT) clay content (i.e. 0.6 wt%), duly identified by an our previous theoretical study based on Design of Experiment (DoE), are presented. Dynamic-mechanical analysis (DMA) reveal that even the introduction of higher HT loading (up to 1%wt) don't affect significantly the mechanical properties of the nanocomposites while morphological investigations show an effective synergy between clay and carbon nanotubes that leads to peculiar micro/nanostructures that favor the creation of the electrical conductive network inside the insulating resin. An electrical characterization is carried out in terms of DC electrical conductivity, percolation threshold (EPT) and frequency response in the range 10Hz-1MHz. In particular, the measurements of the DC conductivity allow to obtain the typical "percolation" curve also found for classical CNT-polymer mixtures and a value of about 2 S/m for the electrical conductivity is achieved at the highest considered CNTs concentration (i.e. 1 wt%). The results suggest that multiphase nanocomposites obtained incorporating dispersive nanofillers, in addition to the conductive one, may be a valid alternative to the polymer blends, to improve the properties of the polymeric materials thus able to meet high demands, particularly concerning their mechanical and thermal stability and electrical features required in the aircraft engineering.

  20. Relationship of subseafloor microbial diversity to sediment age and organic carbon content

    Science.gov (United States)

    Walsh, E. A.; Kirkpatrick, J. B.; Sogin, M. L.; D'Hondt, S. L.

    2013-12-01

    Our tag pyrosequencing investigation of four globally distant sites reveals sediment age and total organic carbon content to be significant components in understanding subseafloor diversity. Our sampling locations include two sites from high-productivity regions (Indian Ocean and Bering Sea) and two from moderate-productivity (eastern and central equatorial Pacific Ocean). Sediment from the high-productivity sites has much higher TOC than sediment from the moderate-productivity equatorial sites. We applied a high-resolution 16S V4-V6 tag pyrosequencing approach to 24 bacterial and 17 archaeal samples, totaling 602,502 reads. We identified1,291 archaeal and 15,910 bacterial OTUs (97%) from these reads. We analyzed bacterial samples from all four sites in addition to archaeal samples from our high productivity sites. These high productivity, high TOC sites have a pronounced methane-rich sulfate-free zone at depth from which archaea have been previously considered to dominate (Biddle et al., 2006). At all four locations, microbial diversity is highest near the seafloor and drops rapidly to low but stable values with increasing sediment depth. The depth at which diversity stabilizes varies greatly from site to site, but the age at which it stabilizes is relatively constant. At all four sites, diversity reaches low stable values a few hundred thousand years after sediment deposition. The sites with high total organic carbon (high productivity sites) generally exhibit higher diversity at each sediment age than the sites with lower total organic carbon (moderate-productivity sites). Archaeal diversity is lower than bacterial diversity at every sampled depth. Biddle, J.F., Lipp, J.S., Lever, M.A., Lloyd, K.G., Sørensen, K.B., Anderson, R. et al. (2006) Heterotrophic Archaea dominate sedimentary subsurface ecosystems off Peru. PNAS 103: 3846-3851.

  1. Conductive additive content balance in Li-ion battery cathodes: Commercial carbon blacks vs. in situ carbon from LiFePO{sub 4}/C composites

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, Veronica; Goni, Aintzane; Muro, Izaskun Gil de; Rojo, Teofilo [Departamento de Quimica Inorganica, Universidad del Pais Vasco UPV/EHU, P.O. Box. 644, 48080, Bilbao (Spain); de Meatza, Iratxe; Bengoechea, Miguel [Energy Department, CIDETEC-IK4, P Miramon 196, Parque Tecnologico de San Sebastian, 20009, San Sebastian (Spain); Cantero, Igor [Departamento I+D+i Nuevas Tecnologias, CEGASA, Artapadura, 11, 01013 Vitoria-Gasteiz (Spain)

    2010-11-15

    Two samples of commercial conducting carbon black and the carbon generated in situ during LiFePO{sub 4}/C composite synthesis from citric acid are studied, with the aim of finding out whether carbon from the composite can fulfil the same function as carbon black in the electrode blend for a Li-ion battery. For this purpose, the carbon samples are analyzed by several techniques, such as X-ray diffraction, Raman spectroscopy, transmission electron microscopy, granulometry, BET specific area and conductivity measurements. Different cathode compositions and component proportions are tested for pellet and cast electrodes. Electrochemical results show that a moderate reduction of commercial carbon black content in both kinds of cathodes, by adding more LiFePO{sub 4}/C composite, enhanced the electrochemical behaviour by around 10%. In situ generated carbon can partially replace commercial conducting carbon black because its high specific surface probably enhances electrolyte penetration into the cathode, but it is always necessary to maintain a minimum amount of carbon black that provides better conductivity in order to obtain a good electrochemical response. (author)

  2. Low carbon content and carbon-free refractory materials with high thermal shock resistance; Thermoschockbestaendige feuerfeste Erzeugnisse mit geringerem Kohlenstoffgehalt bzw. kohlenstofffreie Erzeugnisse

    Energy Technology Data Exchange (ETDEWEB)

    Brachhold, Nora; Aneziris, C.G.; Stein, Volker; Roungos, Vasileios; Moritz, Kirsten [TU Bergakademie Freiberg (TUBAF) (DE). Inst. fuer Keramik, Glas- und Baustofftechnik (IKGB)

    2012-07-01

    Carbon bonded refractories are essential for steelmaking due to their excellent thermal shock resistance. The research on carbon reduced and carbon-free materials is necessary to manufacture high quality stainless steels tending carbon pick-up in contact to conventional refractory materials. Further advantages are reduced emissions of CO{sub 2} and energy saving potentials due to better heat insulation properties. The challenge is to develop alternative materials with lower carbon contents but with the necessary thermal shock resistance. The Priority Programme 1418 funded by the German Research Foundation (DFG) concentrates on this problem. In this article two materials are presented. First, the carbon content could be reduced by nanoscaled additives resulting in better bonding between matrix and oxidic components. Second, an AL{sub 2}O{sub 3}-rich carbon-free material is presented showing a very good thermal shock resistance due to its designed microstructure. Finally, a steel casting simulator is introduced to test the new materials under nearly real conditions. (orig.)

  3. Petrologic and stable isotopic studies of a fossil hydrothermal system in ultramafic environment (Chenaillet ophicalcites, Western Alps, France): Processes of carbonate cementation

    Science.gov (United States)

    Lafay, Romain; Baumgartner, Lukas P.; Stephane, Schwartz; Suzanne, Picazo; German, Montes-Hernandez; Torsten, Vennemann

    2017-12-01

    The Late Jurassic Chenaillet ophiolitic complex (Western Alps) represents parts of an oceanic core-complex of the Liguria-Piemonte domain. A model for the origin and evolution of the Chenaillet ophicalcites based on textural and isotopic characterization is presented. The Chenaillet ophicalcites correspond to brecciated serpentinized peridotites that record seafloor shallow serpentinization at a minimum temperatures of 150 °C followed by authigenic carbonation. Carbonation starts with a network of micrometric to millimetric pre- or syn-clast formation calcite veins accompanied by a pervasive carbonation of residual olivine and serpentine inside the serpentinite mesh core. A matrix of small calcite (values that range between - 5‰ and + 0.4‰. The lower values were obtained for calcite within the serpentinite clasts. The δ18O (VSMOW) values have a range between + 11‰ and + 16‰ in carbonated clasts. The δ18O values in the matrix are fairly homogeneous with an average at + 12‰ and the late calcite veins have values between + 12.5 and + 15.5‰. These values suggest a relatively high temperature of formation for all the carbonates. Carbonates within clast are mainly characterized by a formation temperature in the range of 110 °C to 180 °C assuming a δ18O value of seawater of 0‰, the matrix forms at a temperature of ca. 165 °C. Late veins are characterized by a formation temperature ranging between 120and 155 °C. We propose a model where serpentinization is followed by discrete carbonation then brecciation and cementation as a consequence of continuous hydrothermal fluid circulation in the serpentinite basement. This is comparable to observations made in the stockwork of present-day long-lived oceanic hydrothermal systems.

  4. Enhancing Phenolic Contents and Antioxidant Potentials of Antidesma thwaitesianum by Supercritical Carbon Dioxide Extraction

    Directory of Open Access Journals (Sweden)

    Warut Poontawee

    2015-01-01

    Full Text Available Supercritical fluid extraction (SFE has increasingly gained attention as an alternative technique for extraction of natural products without leaving toxic residues in extracts. Antidesma thwaitesianum Muell. Arg. (Phyllanthaceae, or ma mao, has been reported to exhibit antioxidant health benefits due to its phenolic constituents. To determine whether SFE technique could impact on phenolic contents and associated antioxidant potentials, ripe fruits of Antidesma thwaitesianum (Phyllanthaceae were extracted using supercritical carbon dioxide (SC-CO2 and conventional solvents (ethanol, water. The results showed that the SC-CO2 extract contained significantly higher yield, total phenolic, flavonoid, and proanthocyanidin contents than those obtained from ethanol and water. It also demonstrated the greatest antioxidant activities as assessed by ABTS radical cation decolorization, DPPH radical scavenging, and ferric reducing antioxidant power (FRAP assays. Further analysis using high-performance liquid chromatography with diode array and mass spectrometry detectors (HPLC-DAD/MSD revealed the presence of catechin as a major phenolic compound of Antidesma thwaitesianum (Phyllanthaceae, with the maximum amount detected in the SC-CO2 extract. These data indicate that SFE technology improves both quantity and quality of Antidesma thwaitesianum fruit extract. The findings added more reliability of using this technique to produce high added value products from this medicinal plant.

  5. Can mud (silt and clay) concentration be used to predict soil organic carbon content within seagrass ecosystems?

    KAUST Repository

    Serrano, Oscar

    2016-09-07

    The emerging field of blue carbon science is seeking cost-effective ways to estimate the organic carbon content of soils that are bound by coastal vegetated ecosystems. Organic carbon (C-org) content in terrestrial soils and marine sediments has been correlated with mud content (i.e., silt and clay, particle sizes <63 mu m), however, empirical tests of this theory are lacking for coastal vegetated ecosystems. Here, we compiled data (n = 1345) on the relationship between C-org and mud contents in seagrass ecosystems (79 cores) and adjacent bare sediments (21 cores) to address whether mud can be used to predict soil C-org content. We also combined these data with the delta C-13 signatures of the soil C-org to understand the sources of Corg stores. The results showed that mud is positively correlated with soil C-org content only when the contribution of seagrass-derived C-org to the sedimentary C-org pool is relatively low, such as in small and fast-growing meadows of the genera Zostera, Halodule and Halophila, and in bare sediments adjacent to seagrass ecosystems. In large and long-living seagrass meadows of the genera Posidonia and Amphibolis there was a lack of, or poor relationship between mud and soil C-org content, related to a higher contribution of seagrass-derived C-org to the sedimentary C-org pool in these meadows. The relatively high soil C-org contents with relatively low mud contents (e.g., mud-C-org saturation) in bare sediments and Zostera, Halodule and Halophila meadows was related to significant allochthonous inputs of terrestrial organic matter, while higher contribution of seagrass detritus in Amphibolis and Posidonia meadows disrupted the correlation expected between soil C-org and mud contents. This study shows that mud is not a universal proxy for blue carbon content in seagrass ecosystems, and therefore should not be applied generally across all seagrass habitats. Mud content can only be used as a proxy to estimate soil C-org content for

  6. Enhanced cycle stability of micro-sized Si/C anode material with low carbon content fabricated via spray drying and in situ carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dingsheng; Gao, Mingxia, E-mail: gaomx@zju.edu.cn; Pan, Hongge; Liu, Yongfeng; Wang, Junhua; Li, Shouquan; Ge, Hongwei

    2014-08-01

    Highlights: • Micro-sized Si/C composites were fabricated via. spray drying and carbonization. • Multi-morphology carbon was formed in the Si/C composites. • Si/C composite with 5.6 wt.% C provides significant improved cycling stability. • Multi-morphology carbon plays effective role in improving the electrochemical property. • The method provides potential for mass production of superior Si-based anode materials. - Abstract: Micro-sized Si/C composites with in situ introduced carbon of multi-morphology were fabricated via spray drying a suspension of commercial micro-sized Si and citric acid followed by a carbonization. Different ratios of Si to citric acid were used to optimize the composition and structure of the composites and thus the electrochemical performance. Carbon flakes including crooked and flat ones were well dispersed in between the Si particles, forming Si/C composites. Floc-like carbon layers and carbon fragments were also found to cover partially the Si particles. The Si/C composite with a low carbon content of 5.6 wt.% provides an initial reversible capacity of 2700 mA h/g and a capacity of 1860 mA h/g after 60 cycles at a current density of 100 mA/g as anode material for lithium-ion batteries (LIBs), which are much higher than those of pristine Si and the Si/C composites with higher carbon content. The mechanism of the enhancement of electrochemical performance of the micro-sized Si/C composite is discussed. The fabrication method and the structure design of the composites offer valuable potential in developing adaptable Si-based anode materials for industrial applications.

  7. Total carbon content and humic substances quality in selected subtypes of Cambisols

    Directory of Open Access Journals (Sweden)

    Veronika Petrášová

    2009-01-01

    Full Text Available Cambisols cover an estimated 45% of agricultural soils in the Czech Republic. We aimed our work at stabile forms of organic carbon and humic substances quality in Cambisols under different types of soil management (grassland and arable soil. Object of our study were the following subtypes of Cambisols: Eutric Cambisol (locality Vatín – arable soil, Eutric Cambisol (locality Vatín – grassland, Haplic Cambisol (locality Náměšť n/Oslavou – arable soil, Leptic Cambisol (locality Ocmanice – grassland, Haplic Cambisol (locality Nové Město na Moravě – arable soil, Haplic Cambisol (locality Přemyslov – Tři Kameny – grassland, Arenic Cambisol (locality Pocoucov – arable soil, Dystric Cambisol (locality Sněžné – arable soil, Dystric Cambisol (locality Velká Skrovnice – arable soil, Dystric Cambisol (locality Vojnův Městec – arable soil. Non-destructive spectroscopic methods such as UV-VIS spectroscopy, synchronous fluorescence spectroscopy (SFS and 13C NMR spectroscopy for humic substances (HS quality assessment were used. Total organic carbon (TOC content was determined by oxidimetric titration. Fractionation of HS was made by short fractionation method. Isolation of pure humic ­acids (HA preparation was made according to the standard IHSS method.Results showed that TOC and humus content varied from 2.70 % (grassland to 1.3 % (arable soil. Ave­ra­ge HS sum was 8.4 mg / kg in grassland and 6.4 mg / kg in arable soil. Average HA sum was 3.6 mg / kg in grassland and 3 mg / kg in arable soil. Fulvic acids (FA content was 4.7 mg / kg in grassland and 3.7 mg / kg in arable soil. HS quality was low and very similar for all studied samples. HA/FA ratio low (< 1. HS absorbance in UV-VIS spectral range was low and similar in all studied samples. Higher absorption in this spectral range was closely connected with higher HS content. Also in 2D-synchronous fluorescence scan spectra

  8. Stable isotopic investigations of early development in extant and fossil chambered cephalopods I. Oxygen isotopic composition of eggwater and carbon isotopic composition of siphuncle organic matter in Nautilus

    Science.gov (United States)

    Crocker, Kimberley C.; DeNiro, Michael J.; Ward, Peter D.

    1985-12-01

    Eggwaters from the chambered cephalopod Nautilus are depleted in both 18O and deuterium relative to ambient seawater. Eggwaters from six other species, including the related chambered cephalopod Sepia, do not show such depletion. These observations indicate that the previously observed step towards more positive δ 18O values in calcium carbonate laid down after Nautilus hatches, relative to carbonate precipitated prior to hatching, can be explained by equilibration of the carbonate with water in the egg before hatching and with seawater after hatching. The presence of an oxygen isotope difference between eggwater and seawater for Nautilus and its absence for Sepia suggest that hatching will be recorded in the δ 18O values of shell carbonates for some but not all extinct and extant chambered cephalopods. The δ 13C values of the organic fraction of the siphuncle in Nautilus do not show any consistent pattern with regard to the time of formation before or after hatching. This observation suggests that the minimum in δ 13C values previously observed for calcium carbonate precipitated after Nautilus hatches is not caused by a change in food sources once the animal becomes free-swimming, as has been suggested.

  9. The carbon isotope ratios and contents of mineral elements in leaves of Chinese medicinal plants

    International Nuclear Information System (INIS)

    Lin Zhifang; Sun Guchou; Wang Wei

    1989-01-01

    Leaf carbon isotope ratios and 13 kinds of mineral elements were measured on 36 species of common Chinese medicinal plants in a subtropical monsoon forest of Ding Hu Shan in Guangdong Province. The .delta.13C value were from -26.4 to -32.6%, indicating that all of the species belonged the photosynthetic C3 types. The relative lower value of δ13C was observed in the life form of shrubs. The contents of 7 elements (N, P, K, Ca, Na Mg, Si) were dependent upon the species, life form, medicinal function and medicinal part. Herb type medicine and the used medicinal part of leaves or whole plant showed higher levels of above elements than the others. Among the nine groups with different medicinal functions, it was found that more nitrogen was in the leaves of medicinal plants for hemophthisis, hypertension and stomachic troubles, more phosphorus and potassium were in the leaves for cancer and snake bite medicines, but more calcium and magnesium were in the leaves for curing rheumatics. Ferric, aluminium and manganese were the main composition of microelements in leaves. There were higher content of ferric in leaves for hemophthisis medicine, higher zinc in leaves for cold and hypertension medicine, and higher Cup in leaves of stomachic medicine. It was suggested that the pattern of mineral elements in leaves of Chinese medicinal plants reflected the different properties of absorption and accumulation. Some additional effect due to the high content of certain element might be associated with the main function of that medicine

  10. Modelling global change impacts on soil carbon contents of agro-silvo-pastoral Mediterranean systems

    Science.gov (United States)

    Lozano-García, Beatriz; Muñoz-Rojas, Miriam; Parras-Alcántara, Luis

    2016-04-01

    total of 38 sampling points were selected under two management practices and six different land uses: (1) MEOW-dehesa (D); (2) MEOW-dehesa + some pine trees (D+P); (3) MEOW-dehesa + some cork oaks (D+C); (4) MEOW-dehesa + some gall oaks (D + G); (5) MEOW-dehesa after a clarified process and transformed to olive grove but maintaining isolated oaks (OG) and (6) MEOW-dehesa after a clarified process and transformed to cereal pasture with isolated oaks (C). Preliminary results showed a high heterogeneity of SOC contents along the soil profile for different climate and land use scenarios. The methods used here can be easily implemented in other Mediterranean areas with available information on climate, site, soil and land use. Keywords: CarboSOIL model, land use change, climate change, soil depth, dehesa References: Abd-Elmabod, S.K., Muñoz-Rojas, M., Jordán, A., Anaya-Romero, M., De la Rosa, D., 2014. Modelling soil organic carbon stocks along topographic transects under climate change scenarios using CarboSOIL. Geophys. Res. Abstr. vol. 16 EGU2014-295-1, EGU General Assembly.) Álvaro-Fuentes, J., Easter, M., Paustian, K., 2012. Climate change effects on organic carbon storage in agricultural soils of northeastern Spain. Agric. Ecosyst. Environ. 155, 87-94. Corral-Fernández, R., Parras-Alcántara, L., Lozano-García, B. 2013. Stratification ratio of soil organic C, N and C:N in Mediterranean evergreen oak woodland with conventional and organic tillage. Agric. Ecosyst. Environ. 164, 252-259. Francaviglia, R., Coleman, K., Whitmore, A.P., Doro, L., Urracci, G., Rubino, M., Ledda, L., 2012. Changes in soil organic carbon and climate change - application of the RothC model in agrosilvo-pastoral Mediterranean systems. Agric. Syst. 112, 48- 54. IPCC, 2007. Technical summary. In: Climate Change 2007. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change http://www.ipcc.ch/. Lozano-García, B., Parras-Alcántara, L

  11. Calculation method for determination of carbon in the peatand moss litter of forest swamps by ash content of plant substrates

    Directory of Open Access Journals (Sweden)

    T. T. Efremova

    2016-12-01

    Full Text Available Studies were carried out in the lowmountain part of the Kuznetsk Alatau. The spruce stands were studied in the peaty valley of river Tunguzhul and swamp near Agaskyr Lake (valley of river Pechische, basin of river Black Iyus. The objects belong to the group of high ash content flood plain peat lands of cryogenicseries. We have done the evaluation of organic carbon response to physical-chemical properties – decomposition degree, ash content, and bulk density, connected together (r – 0.5–0.7, that in contrast to carbon, is easy determined analytically. Received results according to stepwise regression analysis characterize the strong conditionality predictors of carbon: multiple determination index R2 – 0.86. The highest partial correlation coefficient with the response belongs to the ash content in range (5–68 %. Partial correlation coefficient values of bulk density and decomposition degree is not significant. The determination index (R2 – 0.93, constant and negative coefficient of pair regression analysis are highly significant and evidence of the strong bond of carbon and organic substrate ash content. The relative error of approximation is in the range of 2–8 % and characterizes the high accuracy of prognosis. Including only one indicator (ash content in the calculation formula makes it convenient and simple in practical application for the carbon content prediction on the forest litter, modern peat soils, buried peat and peat-mineral formations with ash content of 5–68 %. We are the first to present the geochemical characteristics of forest swamps peat mine for the KuznetskAlatau intermountain basins.

  12. Atom and pre-history: the geological framework of fossil man in the light of dating and isotopic data

    International Nuclear Information System (INIS)

    Miskovsky, J.C.; Gibert, E.

    1994-01-01

    The discovery of natural radioactivity and the applications of nuclear physics to the study of sediments and sediment content, allow for the delimitation of the chrono-stratigraphic and paleoclimatic framework of fossil Man. This chronology is based on the development of continental glacial phenomena and is specified through comparison with various methods: paleomagnetic inversion, the variation of oxygen isotopic composition of marine biogenic carbonates and the dating methods. Pleistocene and Holocene era are reviewed. (authors). 9 figs., 90 refs

  13. Fossil power plant automation

    International Nuclear Information System (INIS)

    Divakaruni, S.M.; Touchton, G.

    1991-01-01

    This paper elaborates on issues facing the utilities industry and seeks to address how new computer-based control and automation technologies resulting from recent microprocessor evolution, can improve fossil plant operations and maintenance. This in turn can assist utilities to emerge stronger from the challenges ahead. Many presentations at the first ISA/EPRI co-sponsored conference are targeted towards improving the use of computer and control systems in the fossil and nuclear power plants and we believe this to be the right forum to share our ideas

  14. Influence of moisture content and temperature on degree of carbonation and the effect on Cu and Cr leaching from incineration bottom ash.

    Science.gov (United States)

    Lin, Wenlin Yvonne; Heng, Kim Soon; Sun, Xiaolong; Wang, Jing-Yuan

    2015-09-01

    This study investigated the influence of moisture content and temperature on the degree of carbonation of municipal solid waste (MSW) incineration bottom ash (IBA) from two different incineration plants in Singapore. The initial rate of carbonation was affected by the nominal moisture content used. Carbonation temperature seemed to play a part in changing the actual moisture content of IBA during carbonation, which in turn affected the degree of carbonation. Results showed that 2h of carbonation was sufficient for the samples to reach a relatively high degree of carbonation that was close to the degree of carbonation observed after 1week of carbonation. Both Cu and Cr leaching also showed significant reduction after only 2h of carbonation. Therefore, the optimum moisture content and temperature were selected based on 2h of carbonation. The optimum moisture content was 15% for both incineration plants while the optimum temperature was different for the two incineration plants, at 35°C and 50°C. The effect on Cu and Cr leaching from IBA after accelerated carbonation was evaluated as a function of carbonation time. Correlation coefficient, Pearson's R, was used to determine the dominant leaching mechanism. The reduction in Cu leaching was found to be contributed by both formation of carbonate mineral and reduction of DOC leaching. On the other hand, Cr leaching seemed to be dominantly controlled by pH. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Effects of carbon content and chromium segregation on creep rupture properties of low carbon and medium nitrogen type 316 stainless steel

    International Nuclear Information System (INIS)

    Nakazawa, Takanori; Fujita, Nobuhiro; Kimura, Hidetaka; Komatsu, Hajime; Kotoh, Hiroyuki; Kaguchi, Hitoshi.

    1997-01-01

    The creep rupture properties of type 316 stainless steels containing 0.005-0.022%C and 0.07%N have been investigated at 550degC and 600degC from the aspect of the grain boundary carbide precipitation which was changed with carbon content and chromium segregation. A small amount of carbide precipitated on grain boundaries during creep, because the solubility limit of the carbide is less than 0.005%. The creep rupture ductility of this steel increased with the reduction of carbon content from 0.010% to 0.005% while it decreased with increasing carbon content from 0.010% to 0.020%. Since the amount of grain boundary carbide decreased with reducing carbon content, the increase in ductility was due to the suppression of grain boundary embrittlement caused by the carbide. The creep rupture ductility of this steel was also improved by reducing chromium segregation. This behavior was attributed to the change in carbide morphology from concentrated type to dispersed one, which reduced the grain boundary embrittlement. (author)

  16. Initial Soil Organic Matter Content Influences the Storage and Turnover of Litter-, Root- and Soil Carbon in Grasslands

    Science.gov (United States)

    Liu, L.; Xu, S.; Li, P.; Sayer, E. J.

    2017-12-01

    Grassland degradation is a worldwide problem that often leads to substantial loss of soil organic matter (SOM). Understanding how SOM content influences the stabilization of plant carbon (C) to form soil C is important to evaluate the potential of degraded grasslands to sequester additional C. We conducted a greenhouse experiment using C3 soils with six levels of SOM content and planted the C4 grass Cleistogenes squarrosa and/or added its litter to investigate how SOM content regulates the storage of new soil C derived from litter and roots, the decomposition of extant soil C, and the formation of soil aggregates. We found that microbial biomass carbon (MBC) increased with SOM content, and increased the mineralization of litter C. Both litter addition and planted treatments increased the amount of new C inputs to soil. However, litter addition had no significant impacts on the mineralization of extant soil C, but the presence of living roots significantly accelerated it. Thus, by the end of the experiment, soil C content was significantly higher in the litter addition treatments, but was not affected by planted treatments. The soil macroaggregate fraction increased with SOM content and was positively related to MBC. Overall, our study suggests that as SOM content increases, plant growth and soil microbes become more active, which allows microbes to process more plant-derived C and increases new soil C formation. The interactions between SOM content and plant C inputs should be considered when evaluating soil C turnover in degraded grasslands.

  17. Disentangling the counteracting effects of water content and carbon mass on zooplankton growth

    DEFF Research Database (Denmark)

    Mcconville, Kristian; Atkinson, Angus; Fileman, Elaine S.

    2017-01-01

    Zooplankton vary widely in carbon percentage (carbon mass as a percentage of wet mass), but are often described as either gelatinous or non-gelatinous. Here we update datasets of carbon percentage and growth rate to investigate whether carbon percentage is a continuous trait, and whether its incl...

  18. Effect of organic carbon content of the domestic bentonite on the performance of buffer material in a high-level waste repository

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Won Jin; Lee, Jae Owan; Kang, Chul Hyung [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-12-01

    The organic carbon content of the domestic bentonite have been measured, and its effects on the performance of buffer are analyzed. The total carbon content and the organic carbon content were in the range of 3160 to 3600 and 2400 to 2800 ppm, respectively. The aqueous phase equilibrium concentrations of total carbon and organic carbon in bentonite-water mixture were in the range of 25 to 50 ppm and 4 to 18 ppm, respectively. The results indicate that the effect of organic matter in the domestic bentonite on the performance of buffer material were insignificant. 33 refs., 15 figs., 10 tabs. (Author)

  19. Microelements in fossil bones and the estimation of age

    International Nuclear Information System (INIS)

    Besliu, C.; Olariu, A.; Popescu, I.; Badica, Th.

    1993-01-01

    Neutron activation analysis was used to determine microelements fossil bones and the correlation was found between some elements and the C-14 estimated age of the bones. Fluorine, uranium and manganese content in the bones structure increases with the time elapsed, during fossilization. This means that measurable concentrations of these elements and known environmental conditions could provide a relative dating tool of bones beyond the 70 ky radiocarbon limit, for paleolithic archaeology. Sodium, scandium, iron, and zinc have been also determined in fossil bones, but a relation with the increasing antiquity of the fossil has been observed. (Author)

  20. Fossil energy research meeting

    Energy Technology Data Exchange (ETDEWEB)

    Kropschot, R. H.; Phillips, G. C.

    1977-12-01

    U.S. ERDA's research programs in fossil energy are reviewed with brief descriptions, budgets, etc. Of general interest are discussions related to the capabilities for such research of national laboratories, universities, energy centers, etc. Of necessity many items are treated briefly, but a general overview of the whole program is provided. (LTN)

  1. Fossils and decapod phylogeny

    NARCIS (Netherlands)

    Schram, Frederick R.; Dixon, Christopher

    2003-01-01

    An expanded series of morphological characters developed for a cladistic analysis of extant decapods has yielded a new hypothesis for the phylogeny of the group. Application of this database to selected fossil genera produces some interesting results and demonstrates the feasibility of treating

  2. Functional differences in the allometry of the water, carbon and nitrogen content of gelatinous organisms

    KAUST Repository

    Molina-Ramírez, Axayacatl

    2015-05-19

    We have supplemented available, concurrent measurements of fresh weight (W, g) and body carbon (C, g) (46 individuals, 14 species) and nitrogen (N, g) (11 individuals, 9 species) of marine gelatinous animals with data obtained during the global ocean MALASPINA 2010 Expedition (totalling 267 individuals and 33 species for the W versus C data; totalling 232 individuals and 31 species for the N versus C data). We then used those data to test the allometric properties of the W versus C and N versus C relationships. Overall, gelatinous organisms contain 1.13 ± 1.57% of C (by weight, mean ± SD) in their bodies and show a C:N of 4.56 ± 2.46, respectively, although estimations can be improved by using separate conversion coefficients for the carnivores and the filter feeders. Reduced major axis regression indicates that W increases isometrically with C in the carnivores (cnidarians and ctenophores), implying that their water content can be described by a single conversion coefficient of 173.78 gW(g C)-1, or a C content of 1.17 ± 1.90% by weight, although there is much variability due to the existence of carbon-dense species. In contrast, W increases more rapidly than C in the filter feeders (salps and doliolids), according to a power relationship W = 446.68C1.54. This exponent is not significantly different from 1.2, which is consistent with the idea that the watery bodies of gelatinous animals represent an evolutionary response towards increasing food capture surfaces, i.e. a bottom-up rather than a top-down mechanism. Thus, the available evidence negates a bottom-up mechanism in the carnivores, but supports it in the filter feeders. Last, N increases isometrically with C in both carnivores and filter feeders with C:N ratios of 3.89 ± 1.34 and 4.38 ± 1.21, respectively. These values are similar to those of compact, non-gelatinous organisms and reflect a predominantly herbivorous diet in the filter feeders, which is confirmed by a difference of one trophic level

  3. Functional differences in the allometry of the water, carbon and nitrogen content of gelatinous organisms

    KAUST Repository

    Molina-Ramí rez, Axayacatl; Cá ceres, Carlos; Romero-Romero, Sonia; Bueno, Juan; Gonzá lez-Gordillo, J. Ignacio; Irigoien, Xabier; Sostres, Jorge; Bode, Antonio; Mompeá n, Carmen; Ferná ndez Puelles, Mariluz; Echevarria, Fidel; Duarte, Carlos M.; Acuñ a, José Luis

    2015-01-01

    We have supplemented available, concurrent measurements of fresh weight (W, g) and body carbon (C, g) (46 individuals, 14 species) and nitrogen (N, g) (11 individuals, 9 species) of marine gelatinous animals with data obtained during the global ocean MALASPINA 2010 Expedition (totalling 267 individuals and 33 species for the W versus C data; totalling 232 individuals and 31 species for the N versus C data). We then used those data to test the allometric properties of the W versus C and N versus C relationships. Overall, gelatinous organisms contain 1.13 ± 1.57% of C (by weight, mean ± SD) in their bodies and show a C:N of 4.56 ± 2.46, respectively, although estimations can be improved by using separate conversion coefficients for the carnivores and the filter feeders. Reduced major axis regression indicates that W increases isometrically with C in the carnivores (cnidarians and ctenophores), implying that their water content can be described by a single conversion coefficient of 173.78 gW(g C)-1, or a C content of 1.17 ± 1.90% by weight, although there is much variability due to the existence of carbon-dense species. In contrast, W increases more rapidly than C in the filter feeders (salps and doliolids), according to a power relationship W = 446.68C1.54. This exponent is not significantly different from 1.2, which is consistent with the idea that the watery bodies of gelatinous animals represent an evolutionary response towards increasing food capture surfaces, i.e. a bottom-up rather than a top-down mechanism. Thus, the available evidence negates a bottom-up mechanism in the carnivores, but supports it in the filter feeders. Last, N increases isometrically with C in both carnivores and filter feeders with C:N ratios of 3.89 ± 1.34 and 4.38 ± 1.21, respectively. These values are similar to those of compact, non-gelatinous organisms and reflect a predominantly herbivorous diet in the filter feeders, which is confirmed by a difference of one trophic level

  4. Geographic patterns of carbon dioxide emissions from fossil-fuel burning, hydraulic cement production, and gas flaring on a one degree by one degree grid cell basis: 1950 to 1990

    Energy Technology Data Exchange (ETDEWEB)

    Brenkert, A.L. [ed.] [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center; Andres, R.J. [Univ. of Alaska, Fairbanks, AK (United States). Inst. of Northern Engineering; Marland, G. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Fung, I. [Univ. of Victoria, British Columbia (Canada)]|[National Aeronautics and Space Administration, New York, NY (United States). Goddard Inst. for Space Studies; Matthews, E. [Columbia Univ., New York, NY (United States)]|[National Aeronautics and Space Administration, New York, NY (United States). Goddard Inst. for Space Studies

    1997-03-01

    Data sets of one degree latitude by one degree longitude carbon dioxide (CO{sub 2}) emissions in units of thousand metric tons of carbon (C) per year from anthropogenic sources have been produced for 1950, 1960, 1970, 1980 and 1990. Detailed geographic information on CO{sub 2} emissions can be critical in understanding the pattern of the atmospheric and biospheric response to these emissions. Global, regional and national annual estimates for 1950 through 1992 were published previously. Those national, annual CO{sub 2} emission estimates were based on statistics on fossil-fuel burning, cement manufacturing and gas flaring in oil fields as well as energy production, consumption and trade data, using the methods of Marland and Rotty. The national annual estimates were combined with gridded one-degree data on political units and 1984 human populations to create the new gridded CO{sub 2} emission data sets. The same population distribution was used for each of the years as proxy for the emission distribution within each country. The implied assumption for that procedure was that per capita energy use and fuel mix is uniform over a political unit. The consequence of this first-order procedure is that the spatial changes observed over time are solely due to changes in national energy consumption and nation-based fuel mix. Increases in emissions over time are apparent for most areas.

  5. Blow Hole Cave: An unroofed cave on San Salvador Island, the Bahamas, and its importance for detection of paleokarst caves on fossil carbonate platforms

    Czech Academy of Sciences Publication Activity Database

    Bosák, Pavel; Mylroie, J. E.; Hladil, Jindřich; Carew, J. L.; Slavík, Ladislav

    2002-01-01

    Roč. 31, č. 3 (2002), s. 51-74 ISSN 0583-6050. [Karstological School - Classical Karst: Types of Karst /10./. Pstojna, 26.06.2002-28.06.2002] R&D Projects: GA AV ČR IAA3013809; GA AV ČR IAA3013209 Keywords : carbonate platforms * unroofed caves * gamma-ray spectrometry and wellogging Subject RIV: DB - Geology ; Mineralogy http://carsologica.zrc-sazu.si/downloads/313/slavik.pdf

  6. Biomass, organic carbon and calorific content of zooplankton from the Arabian Sea off Central West coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Nair, V.R.

    Organic carbon content and calorific values of zooplankton varied from 18.35 to 32.49% (av. 27.8%) and from 2.56 to 4.71 k cal. g-1 dry wt (av. 3.99) respectively. Areawise off Gujarat sustained higher standing stock of zooplankton (77.18 mg m-3...

  7. Glacial to interglacial contrast in the calcium carbonate content and influence of Indus discharge in two eastern Arabian sea cores

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    -74. Muller, G. and Gastner, M., 1971. The Karbonat Bombe a simple device for the determination of carbonate content in marine sediments, soil and other materials. Neues Jahrb. Mineral. Monat sh., pp. 466-469. Nair, R.R., Ittekkot, V., Manganani, S...

  8. Observation of WC grain shapes determined by carbon content during liquid phase sintering of WC-Co alloys

    International Nuclear Information System (INIS)

    Sona Kim; Hyoun-Ee Kim; Seok-Hee Han; Jong-Ku Park

    2001-01-01

    In the composite materials of WC-Co alloys, the faceted WC grains as a hard phase are dispersed in the ductile matrix of cobalt. Properties of WC-Co alloys are affected by microstructural factors such as volume fraction of WC phase, size of WC grains, and carbon content (kinds of constituent phases). Although the properties of WC-Co alloys are inevitably affected by the shape of WC grains, the shape of WC grains has not been thrown light on the properties of WC-Co alloys yet, because it has been regarded to have a uniform shape regardless of alloy compositions. It is proved that the WC grains have various shapes varying reversibly with carbon content in the sintered WC-Co compacts. This dependency of grain shape on the carbon content is attributed to asymmetric atomic structure of WC crystal. The {10 1 - 0} prismatic planes are distinguished into two groups with different surface energy according to their atomic structures. The prismatic planes of high surface energy tend to disappear in the compacts with high carbon content. In addition, these high energy prismatic planes tend to split into low energy surfaces in the large WC grains. (author)

  9. Rust Layer Formed on Low Carbon Weathering Steels with Different Mn, Ni Contents in Environment Containing Chloride Ions

    Directory of Open Access Journals (Sweden)

    Gui-qin FU

    2016-11-01

    Full Text Available The rusting evolution of low carbon weathering steels with different Mn, Ni contents under a simulated environment containing chloride ions has been investigated to clarify the correlation between Mn, Ni and the rust formed on steels. The results show that Mn contents have little impact on corrosion kinetics of experimental steels. Content increase of Ni both enhances the anti-corrosion performance of steel substrate and the rust. Increasing Ni content is beneficial to forming compact rust. Semi-quantitative XRD phase analysis shows that the quantity ratio of α/γ*(α-FeOOH/(γ-FeOOH+Fe3O4 decreases as Mn content increases but it increases as Ni content increases. Ni enhances rust layer stability but Mn content exceeding 1.06 wt.% is disadvantageous for rust layer stability. The content increase of Mn does not significantly alter the parameters of the polarization curve. However, as Ni contents increases, Ecorr has shifted to the positive along with decreased icorr values indicating smaller corrosion rate especially as Ni content increases from 0.42 wt.% to 1.50 wt.%.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.12844

  10. Hydrogen content and density in nanocrystalline carbon films of a predominant diamond character

    International Nuclear Information System (INIS)

    Hoffman, A.; Heiman, A.; Akhvlediani, R.; Lakin, E.; Zolotoyabko, E.; Cyterman, C.

    2003-01-01

    Nanocrystalline carbon films possessing a prevailing diamond or graphite character, depending on substrate temperature, can be deposited from a methane hydrogen mixture by the direct current glow discharge plasma chemical vapor deposition method. While at a temperature of ∼880 deg. C, following the formation of a thin precursor graphitic film, diamond nucleation occurs and a nanodiamond film grows, at higher and lower deposition temperatures the films maintain their graphitic character. In this study the hydrogen content, density and nanocrystalline phase composition of films deposited at various temperatures are investigated. We aim to elucidate the role of hydrogen in nanocrystalline films with a predominant diamond character. Secondary ion mass spectroscopy revealed a considerable increase of the hydrogen concentration in the films that accompanies the growth of nanodiamond. It correlates with near edge x-ray adsorption spectroscopy measurements, that showed an appearance of spectroscopic features associated with the diamond structure, and with a substantial increase of the film density detected by x-ray reflectivity. Electron energy loss spectroscopy showed that nanocrystalline diamond films can be deposited from a CH 4 /H 2 mixture with hydrogen concentration in the 80%-95% range. For a deposition temperature of 880 deg. C, the highest diamond character of the films was found for a hydrogen concentration of 91% of H 2 . The deposition temperature plays an important role in diamond formation, strongly influencing the content of adsorbed hydrogen with an optimum at 880 deg. C. It is suggested that diamond nucleation and growth of the nanodiamond phase is driven by densification of the deposited graphitic films which results in high local compressive stresses. Nanodiamond formation is accompanied by an increase of hydrogen concentration in the films. It is suggested that hydrogen retention is critical for stabilization of nanodiamond crystallites. At lower

  11. Radiocarbon Content of Dissolved Organic Carbon in the South Indian Ocean

    Science.gov (United States)

    Bercovici, S. K.; McNichol, A. P.; Xu, L.; Hansell, D. A.

    2018-01-01

    We report four profiles of the radiocarbon content of dissolved organic carbon (DOC) spanning the South Indian Ocean (SIO), ranging from the Polar Front (56°S) to the subtropics (29°S). Surface waters held mean DOC Δ14C values of -426 ± 6‰ ( 4,400 14C years) at the Polar Front and DOC Δ14C values of -252 ± 22‰ ( 2,000 14C years) in the subtropics. At depth, Circumpolar Deep Waters held DOC Δ14C values of -491 ± 13‰ ( 5,400 years), while values in Indian Deep Water were more depleted, holding DOC Δ14C values of -503 ± 8‰ ( 5,600 14C years). High-salinity North Atlantic Deep Water intruding into the deep SIO had a distinctly less depleted DOC Δ14C value of -481 ± 8‰ ( 5,100 14C years). We use multiple linear regression to assess the dynamics of DOC Δ14C values in the deep Indian Ocean, finding that their distribution is characteristic of water masses in that region.

  12. Applied Gaussian Process in Optimizing Unburned Carbon Content in Fly Ash for Boiler Combustion

    Directory of Open Access Journals (Sweden)

    Chunlin Wang

    2017-01-01

    Full Text Available Recently, Gaussian Process (GP has attracted generous attention from industry. This article focuses on the application of coal fired boiler combustion and uses GP to design a strategy for reducing Unburned Carbon Content in Fly Ash (UCC-FA which is the most important indicator of boiler combustion efficiency. With getting rid of the complicated physical mechanisms, building a data-driven model as GP is an effective way for the proposed issue. Firstly, GP is used to model the relationship between the UCC-FA and boiler combustion operation parameters. The hyperparameters of GP model are optimized via Genetic Algorithm (GA. Then, served as the objective of another GA framework, the predicted UCC-FA from GP model is utilized in searching the optimal operation plan for the boiler combustion. Based on 670 sets of real data from a high capacity tangentially fired boiler, two GP models with 21 and 13 inputs, respectively, are developed. In the experimental results, the model with 21 inputs provides better prediction performance than that of the other. Choosing the results from 21-input model, the UCC-FA decreases from 2.7% to 1.7% via optimizing some of the operational parameters, which is a reasonable achievement for the boiler combustion.

  13. Black carbon content in a ponderosa pine forest of eastern Oregon with varying seasons and intervals of prescribed burns

    Science.gov (United States)

    Matosziuk, L.; Hatten, J. A.

    2016-12-01

    Soil carbon represents a significant component of the global carbon cycle. While fire-based disturbance of forest ecosystems acts as a carbon source, the increased temperatures can initiate molecular changes to forest biomass that convert fast cycling organic carbon into more stable forms such as black carbon (BC), a product of incomplete combustion that contains highly-condensed aromatic structures and very low hydrogen and oxygen content. Such forms of carbon can remain in the soil for hundred to thousands of years, effectively creating a long-term carbon sink. The goal of this project is to understand how specific characteristics of prescribed burns, specifically the season of burn and the interval between burns, affect the formation, structure, and retention of these slowly degrading forms of carbon in the soil. Both O-horizon (forest floor) and mineral soil (0-15 cm cores) samples were collected from a season and interval of burn study in Malheur National Forest. The study area is divided into six replicate units, each of which is sub-divided into four treatment areas and a control. Beginning in 1997, each treatment area was subjected to: i) spring burns at five-year intervals, ii) fall burns at five-year intervals, iii) spring burns at 15-year intervals, or iv) fall burns at 15-year intervals. The bulk density, pH, and C/N content of each soil were measured to assess the effect of the burn treatments on the soil. Additionally, the amount and molecular structure of BC in each sample was quantified using the distribution of specific molecular markers (benzene polycarboxylic acids or BPCAs) that are present in the soil following acid digestion.

  14. Renewables vs fossil fuels

    Energy Technology Data Exchange (ETDEWEB)

    Adams, K. (Energy Research and Development Corporation (Australia))

    1992-01-01

    The paper examines some of the factors which will influence the future mix of energy from fossil fuels and renewable sources in Australia. Aspects covered include: the present energy situation; impact of environmental issues; potential for renewable energy; motivators for change; and research and development. It is concluded that the future for fossil fuels and renewable energy is dependent on a number of complex factors, many of which are currently unknown. The key factor is economic viability and that will be influenced by a range of factors such as policies of the Australian and overseas governments in relation to pollution and environment protection (reflected in the cost of meeting such requirements), exploration and production costs (also influenced by government policies), availability of supply, rate of technological development and the size of export markets. 8 refs., 2 figs., 1 tab.

  15. A fossils detector

    International Nuclear Information System (INIS)

    Buffetaut, E.

    1998-01-01

    Because fossil bones are often rich in uraninite they can be detected using a portable gamma-ray detector run over the prospected site. Zones with higher radioactivity are possible accumulations of bones or skeletons. This method invented by R. Jones from the University of Utah (Salt Lake City, USA) has been successfully used in the field and led to the discovery of new dinosaur skeletons. Short paper. (J.S.)

  16. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century.

    Science.gov (United States)

    Graven, Heather D

    2015-08-04

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  17. Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

    Directory of Open Access Journals (Sweden)

    V. Ulevicius

    2016-05-01

    Full Text Available In early spring the Baltic region is frequently affected by high-pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1 was measured by an Aerodyne aerosol chemical speciation monitor (ACSM and a source apportionment with the multilinear engine (ME-2 running the positive matrix factorization (PMF model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m−3 and black carbon (BC up to 17 µg m−3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C measurements of the elemental (EC and organic (OC carbon fractions. Non-fossil organic carbon (OCnf was the dominant fraction of PM1, with the primary (POCnf and secondary (SOCnf fractions contributing 26–44 % and 13–23 % to the total carbon (TC, respectively. 5–8 % of the TC had a primary fossil origin (POCf, whereas the contribution of fossil secondary organic carbon (SOCf was 4–13 %. Non-fossil EC (ECnf and fossil EC (ECf ranged from 13–24 and 7–13 %, respectively. Isotope ratios of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

  18. Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

    Science.gov (United States)

    Ulevicius, Vidmantas; Byčenkienė, Steigvilė; Bozzetti, Carlo; Vlachou, Athanasia; Plauškaitė, Kristina; Mordas, Genrik; Dudoitis, Vadimas; Abbaszade, Gülcin; Remeikis, Vidmantas; Garbaras, Andrius; Masalaite, Agne; Blees, Jan; Fröhlich, Roman; Dällenbach, Kaspar R.; Canonaco, Francesco; Slowik, Jay G.; Dommen, Josef; Zimmermann, Ralf; Schnelle-Kreis, Jürgen; Salazar, Gary A.; Agrios, Konstantinos; Szidat, Sönke; El Haddad, Imad; Prévôt, André S. H.

    2016-05-01

    In early spring the Baltic region is frequently affected by high-pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB) on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1) was measured by an Aerodyne aerosol chemical speciation monitor (ACSM) and a source apportionment with the multilinear engine (ME-2) running the positive matrix factorization (PMF) model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m-3 and black carbon (BC) up to 17 µg m-3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C) measurements of the elemental (EC) and organic (OC) carbon fractions. Non-fossil organic carbon (OCnf) was the dominant fraction of PM1, with the primary (POCnf) and secondary (SOCnf) fractions contributing 26-44 % and 13-23 % to the total carbon (TC), respectively. 5-8 % of the TC had a primary fossil origin (POCf), whereas the contribution of fossil secondary organic carbon (SOCf) was 4-13 %. Non-fossil EC (ECnf) and fossil EC (ECf) ranged from 13-24 and 7-13 %, respectively. Isotope ratios of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

  19. Effect of Carbon Content on the Properties of Iron-Based Powder Metallurgical Parts Produced by the Surface Rolling Process

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    2018-01-01

    Full Text Available In recent years, the rolling densification process has become increasingly widely used to strengthen powder metallurgy parts. The original composition of the rolled powder metallurgy blank has a significant effect on the rolling densification technology. The present work investigated the effects of different carbon contents (0 wt. %, 0.2 wt. %, 0.45 wt. %, and 0.8 wt. % on the rolling densification. The selection of the raw materials in the surface rolling densification process was analyzed based on the pore condition, structure, hardness, and friction performance of the materials. The results show that the 0.8 wt. % carbon content of the surface rolling material can effectively improve the properties of iron-based powder metallurgy parts. The samples with 0.8 wt. % carbon have the highest surface hardness (340 HV0.1 and the lowest surface friction coefficient (0.35. Even if the dense layer depth is 1.13 mm, which is thinner than other samples with low carbon content, it also meets the requirements for powder metallurgy parts such as gears used in the auto industry.

  20. Optimisation of the microporous layer for a polybenzimidazole-based high temperature PEMFC - effect of carbon content

    Energy Technology Data Exchange (ETDEWEB)

    Lobato, J.; Canizares, P.; Rodrigo, M.A.; Ubeda, D.; Pinar, F.J.; Linares, J.J. [Department of Chemical Engineering, University of Castilla-La Mancha, Av. Camilo Jose Cela, n 12. 13071, Ciudad Real (Spain)

    2010-10-15

    This work aims at studying the role of the microporous layer (MPL) in electrodes prepared for high temperature PBI-based PEMFC. The two main components of this layer are carbon black and a polymeric binder (Teflon). This work addresses the effect of the MPL carbon amount on the performance of a high temperature PEMFC. Thus, gas diffusion layers (GDLs) containing MPL with different carbon contents (from 0.5 to 4 mg cm{sup -2}) were prepared. Firstly, they were physically characterised by Hg-porosimetry measuring pore size distribution, porosity, tortuosity and mean pore size. Permeability measurements were also performed. The higher the carbon content was the lower both porosity and permeability were. Afterwards, electrodes were prepared with these GDLs and were electrochemically characterised. Electrochemical surface area (ESA) was determined and fuel cell performance was evaluated under different fuel and comburent stoichiometries, supporting these results with impedance spectra. This made it possible to see the benefits of the MPL inclusion in the electrode structure, with a significant increase in the fuel cell performance and ESA. Once the goodness of the MPL was confirmed, result analysis led to an optimum MPL composition of 2 mg cm{sup -2} of carbon for both electrodes, anode and cathode. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  1. Mexico city aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0 – Part 2: Analysis of the biomass burning contribution and the non-fossil carbon fraction

    Directory of Open Access Journals (Sweden)

    A. C. Aiken

    2010-06-01

    does not show an increase during the fire periods or a correlation with fire counts, FLEXPART-predicted FIFs or fire tracers, indicating that it is dominated by urban and/or regional sources and not by the fires near the MCMA.

    A new 14C aerosol dataset is presented. Both this new and a previously published dataset of 14C analysis suggest a similar BBOA contribution as the AMS and chemical mass balance (CMB, resulting in 13% higher non-fossil carbon during the high vs. low regional fire periods. The new dataset has ~15% more fossil carbon on average than the previously published one, and possible reasons for this discrepancy are discussed. During the low regional fire period, 38% of organic carbon (OC and 28% total carbon (TC are from non-fossil sources, suggesting the importance of urban and regional non-fossil carbon sources other than the fires, such as food cooking and regional biogenic SOA. The ambient BBOA/ΔCH3CN ratio is much higher in the afternoon when the wildfires are most intense than during the rest of the day. Also, there are large differences in the contributions of the different OA components to the surface concentrations vs. the integrated column amounts. Both facts may explain some apparent disagreements between BB impacts estimated from afternoon aircraft flights vs. those from 24-h ground measurements.

    We show that by properly accounting for the non-BB sources of K, all of the BB PM estimates from MILAGRO can be reconciled. Overall, the fires from the region near the MCMA are estimated to contribute 15–23% of the OA and 7–9% of the fine PM at T0 during MILAGRO, and 2–3% of the fine PM as an annual average. The 2006 MCMA emissions inventory contains a substantially lower impact of the forest fire emissions, although a fraction of these emissions occur just outside of the MCMA inventory area.

  2. Dependence of microhardness of coke on carbon content and final coking temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kaloc, M.; Dvorak, P.

    1995-12-31

    At present time is important the coke-quality, tested by various methods again. The new methods of evaluation of coke quality as e.g. CSR, CRI, ACRI etc. demonstrate, that the mechanical stability parameters are in connection of microstructure of coke mass. The purpose of present paper is to investigate the dependence of microhardness on the carbon content and the final carbonisation temperature in the coal-coke series. The samples prepared experimentally in more series from different coal blends from 20{degrees}C to 1100{degrees}C were investigated both mega- and microscopically. The tests of microhardness are based on the use of the Hanemann microhardness tester. Principally this method consists in impressing the diamond pyramid into the surface of the sample. The data on the pressure applied are subtracted on the scale of load. An important factor influencing the results is the choice of the points from which the sample is to be withdrawn. The choice is dependent on the aim to be achieved. For the determination of an average microhardness it is sufficient to take sample from the middle part of the coke block representing the half width of the coking chamber. The choice of the point is also of great importance. In strong and homogeneous walls, sharply bounded, impressions can be found with a distinct diagonal cross. In thin walls the impressions are distinguished by distinct boundaries, the middle part, however, not being distinct as the pyramidal point did not penetrate the wall. Impressions providing accurate values are those distinctly bounded by a distinct diagonal cross. The walls not having been chosen correctly, the errors reveal themselves as the scattering of the points in the diagrams of microhardness.

  3. The effect of type-B carbonate content on the elasticity of fluorapatite

    Science.gov (United States)

    Cámara, Fernando; Curetti, Nadia; Benna, Piera; Abdu, Yassir A.; Hawthorne, Frank C.; Ferraris, Cristiano

    2018-03-01

    The mechanical behavior of carbonate-bearing fluorapatite (CFAP) (with up to 5.5 wt% CO3) was investigated at high pressure up to 7 GPa. The incorporation of carbonate in CFAP samples was investigated by FTIR spectroscopy. The chemical formulae and cell parameters are Ca4.90Fe0.04 (PO4)2.87 (CO3)0.13 F1.23 and a = 9.3527(1), c = 6.8752(1) Å, V = 520.83(1) Å3 for the FOW CFAP (Fowey Consols area, UK), and Ca4.97Sr0.03 (PO4)2.55 (CO3)0.45 F1.42 and a = 9.3330(1), c = 6.8984(1) Å, V = 520.38(1) Å3 for the FRA CFAP (Framont region, France). Preliminary characterization at ambient conditions was done by single-crystal X-ray diffraction study. The structure refinements, in space group P63/m, confirm a type-B substitution of the phosphate (PO4)3- group by the carbonate ion (CO3)2-. The site occupancies for the C atom are 0.04 for FOW and 0.11 for FRA CFAP, in quite good agreement with the 1.6 and 5.5 wt% CO3 amount obtained by analytical methods. Single-crystal high-pressure XRD study on the two type-B CFAP samples was performed. The FOW and FRA crystals were mounted concurrently in a ETH-type DAC and cell parameters were determined at 26 different pressures up to 6.86 GPa at room T. The variation with pressure of the unit-cell parameters and volume shows no discontinuity that could be related to any possible phase transition in the P range investigated. The linear compressibility coefficients are β a = 3.63 × 10-3 GPa-1 and β c = 2.47 × 10-3 GPa-1 for FOW, and β a = 3.67 × 10-3 GPa-1 and β c = 2.65 × 10-3 GPa-1 for FRA, giving an axial anisotropy of β a :β c = 1.47:1 and 1.38:1, respectively. The P-V data were fitted by a second-order Birch-Murnaghan EoS and the resulting BM2-EoS coefficients are V 0 = 519.81(7) Å3, K T0 = 92.1(3) GPa for FOW, and V 0 = 518.95(9) Å3, K T0 = 89.1(4) GPa for FRA CFAP. The results obtained indicate that a 5.5 wt% CO3 content (type-B) reduces the isothermal bulk modulus by about 9%.

  4. A one-step carbonization route towards nitrogen-doped porous carbon hollow spheres with ultrahigh nitrogen content for CO 2 adsorption

    KAUST Repository

    Wang, Yu

    2015-01-01

    © The Royal Society of Chemistry 2015. Nitrogen doped porous carbon hollow spheres (N-PCHSs) with an ultrahigh nitrogen content of 15.9 wt% and a high surface area of 775 m2 g-1 were prepared using Melamine-formaldehyde nanospheres as hard templates and nitrogen sources. The N-PCHSs were completely characterized and were found to exhibit considerable CO2 adsorption performance (4.42 mmol g-1).

  5. Risks attributable to water quality changes in shallow potable aquifers from geological carbon sequestration leakage into sediments of variable carbonate content

    DEFF Research Database (Denmark)

    Cahill, Aaron Graham; Jakobsen, Rasmus; Mathiesen, Tina Bay

    2013-01-01

    Denmark including; siliceous, carbonate and clay materials. Sediments were exposed to CO2 and hydro-geochemical effects were observed in order to improve general understanding of trace metal mobility, quantify carbonate influence, assess risks attributable to fresh water resources from a potential leak...... and aid monitoring measurement and verification (MMV) program design. Results demonstrate control of water chemistry by sediment mineralogy and most significantly carbonate content, for which a potential semi-logarithmic relationship with pH and alkalinity was observed. In addition, control of water...... changes in water chemistry with large increases in all major and trace elements coupled to minimal reductions in pH due to high buffering capacity. Silicate dominated sediments exhibited small changes in dissolved major ion concentrations and the greatest reductions in pH, therefore displaying...

  6. Influence of atmospheric 14CO2 on determination of the ratio of biogenic carbon to fossil one in exhaust gases using accelerator mass spectrometry. Experimental evaluation for industrial flue gases

    International Nuclear Information System (INIS)

    Yunoki, Shunji; Saito, Masaaki; Nagakawa, Yoshiyasu

    2012-01-01

    The influence of atmospheric 14 CO 2 was evaluated on the determination of biogenic carbon ratios in industrial flue gases using accelerated mass spectrometry(AMS). Bioethanol, n-hexane, and their mixtures were combusted with a four-stroke engine, and 14 CO 2 in exhaust gases was analyzed by AMS. The experimental biogenic carbon ratio determined by ASTM D6866 method was 1.2 times higher than the theoretical value of mixed fuel containing 3.18% biogenic carbons. In general, the influence of atmospheric 14 CO 2 taken in combustion gases is neglected. It seems that the error cannot be neglected under international trading of emission allowances, where a large amount of carbons in the fuel were evaluated. The experimental value became to be the theoretical value by subtracting the amount of atmospheric 14 C from that of the samples. As the contents of biofuel increased, the experimental biogenic carbon ratios reached the theoretical values and the influence of atmospheric 14 CO 2 decreased. We recommend that the influence of atmospheric 14 CO 2 should be corrected when fuel samples contain low amounts of 14 C. (author)

  7. High-performance supercapacitors of carboxylate-modified hollow carbon nanospheres coated on flexible carbon fibre paper: Effects of oxygen-containing group contents, electrolytes and operating temperature

    International Nuclear Information System (INIS)

    Phattharasupakun, Nutthaphon; Wutthiprom, Juthaporn; Suktha, Phansiri; Iamprasertkun, Pawin; Chanlek, Narong; Shepherd, Celine; Hadzifejzovic, Emina; Moloney, Mark G.; Foord, John S.; Sawangphruk, Montree

    2017-01-01

    Although functionalized carbon-based materials have been widely used as the supercapacitor electrodes, the optimum contents of the functional groups, the charge storage mechanisms, and the effects of electrolytes and operating temperature have not yet been clearly investigated. In this work, carboxylate-modified hollow carbon nanospheres (c-HCN) with different functional group contents synthesized by an oxidation process of carbon nanospheres with nitric acid were coated on flexible carbon fibre paper and used as the supercapacitor electrodes. An as-fabricated supercapacitor of the c-HCN with a finely tuned 6.2 atomic % of oxygen of the oxygen-containing groups in an ionic liquid electrolyte exhibits a specific capacitance of 390 F g"−"1, a specific energy of 115 Wh kg"−"1, and a maximum specific power of 13548 W kg"−"1 at 70 °C. The charge storage mechanism investigated is based on the chemical adsorption of the ionic liquid electrolyte on the c-HCN electrode. This process is highly reversible leading to high capacity retention. The supercapacitor in this work may be practically used in many high energy and power applications.

  8. Carbon isotopes from fossil packrat pellets and elevational movements of Utah agave plants reveal the Younger Dryas cold period in Grand Canyon, Arizona

    Science.gov (United States)

    Cole, K.L.; Arundel, S.T.

    2005-01-01

    Carbon isotopes in rodent fecal pellets were measured on packrat (Neotoma spp.) middens from the Grand Canyon, Arizona. The pellet samples reflect the abundance of cold-intolerant C4 and Crassulacean acid metabolism (CAM) plant species relative to the predominant C3 vegetation in the packrat diet. The temporal sequence of isotopic results suggests a temperature decline followed by a sharp increase corresponding to the B??lling/Aller??d-Younger Dryas - early Holocene sequence. This pattern was then tested using the past distribution of Utah agave (Agave utahensis). Spatial analyses of the range of this temperature-sensitive CAM species demonstrate that its upper elevational limit is controlled by winter minimum temperature. Applying this paleotemperature proxy to the past elevational limits of Utah agave suggests that minimum winter temperatures were ???8??C below modern values during the Last Glacial Maximum, 4.5-6.5 ??C below modern during the B??lling/Aller??d, and 7.5-8.7 ??C below modern during the early Younger Dryas. As the Younger Dryas terminated, temperatures warmed ???4 ??C between ca. 11.8 ka and 11.5 ka. These extreme fluctuations in winter minimum temperature have not been generally accepted for terrestrial paleoecological records from the arid southwestern United States, likely because of large statistical uncertainties of older radiocarbon results and reliance on proxies for summer temperatures, which were less affected. ?? 2005 Geological Society of America.

  9. Fossilization Processes in Thermal Springs

    Science.gov (United States)

    Farmer, Jack D.; Cady, Sherry; Desmarais, David J.; Chang, Sherwood (Technical Monitor)

    1995-01-01

    To create a comparative framework for the study of ancient examples, we have been carrying out parallel studies of the microbial biosedimentology, taphonomy and geochemistry of modem and sub-Recent thermal spring deposits. One goal of the research is the development of integrated litho- and taphofacies models for siliceous and travertline sinters. Thermal springs are regarded as important environments for the origin and early evolution of life on Earth, and we seek to utilize information from the fossil record to reconstruct the evolution of high temperature ecosystems. Microbial contributions to the fabric of thermal spring sinters occur when population growth rates keep pace with, or exceed rates of inorganic precipitation, allowing for the development of continuous biofilms or mats. In siliceous thermal springs, microorganisms are typically entombed while viable. Modes of preservation reflect the balance between rates of organic matter degradation, silica precipitation and secondary infilling. Subaerial sinters are initially quite porous and permeable and at temperatures higher than about 20 C, organic materials are usually degraded prior to secondary infilling of sinter frameworks. Thus, organically-preserved microfossils are rare and fossil information consists of characteristic biofabrics formed by the encrustation and underplating of microbial mat surfaces. This probably accounts for the typically low total organic carbon values observed in thermal spring deposits. In mid-temperature, (approx. 35 - 59 C) ponds and outflows, the surface morphology of tufted Phormidium mats is preserved through mat underplating by thin siliceous: crusts. Microbial taxes lead to clumping of ceils and/or preferred filament orientations that together define higher order composite fabrics in thermal spring stromatolites (e.g. network, coniform, and palisade). At lower temperatures (less than 35 C), Calothrix mats cover shallow terracette pools forming flat carpets or pustular

  10. A Simple Beta-Function Model for Soil-Water Repellency as a Function of Water and Organic Carbon Contents

    DEFF Research Database (Denmark)

    Karunarathna, Anurudda Kumara; Kawamoto, Ken; Møldrup, Per

    2010-01-01

    Soil-water content (θ) and soil organic carbon (SOC) are key factors controlling the occurrence and magnitude of soil-water repellency (WR). Although expressions have recently been proposed to describe the nonlinear variation of WR with θ, the inclusion of easily measurable parameters in predictive...... conditions for 19 soils were used to test the model. The beta function successfully reproduced all the measured soil-water repellency characteristic, α(θ), curves. Significant correlations were found between model parameters and SOC content (1%-14%). The model was independently tested against data...

  11. Influence of fossil energy applications on environmental pollution

    Energy Technology Data Exchange (ETDEWEB)

    Balat, M.; Ayar, G.; Oguzhan, C.; Uluduz, H.; Faiz, U. [University of Mahallesi, Trabzon (Turkey)

    2007-07-01

    The aim of this work is to investigate influence of fossil energy applications on the environmental pollution. Turkey's high rate of economic growth experienced during much of the 1990s, besides resulting in booming industrial production, also led to higher levels of energy consumption, imports, air and water pollution, and greater risks to the country's environment. Air pollution is a major problem in Turkey, with key pollutants including sulfur dioxide, suspended particulates, nitrogen oxides, and carbon dioxide. In Turkey, carbon dioxide emissions from fossil fuels totaled about 50.07 million tons in 2001. However, fuel share of carbon emissions in 2001 was oil 44.2%, coal 38.8%, and natural gas 16.9%. Total carbon dioxide emissions from fossil fuels are expected to be 104 million tons in 2025.

  12. Determination of oxygen content and carbonate impurity in YBa2Cu3O7-x by diffuse reflectance infrared spectroscopy

    International Nuclear Information System (INIS)

    Merzbacher, C.I.; Bonner, B.P.

    1991-01-01

    Samples of YBa 2 Cu 3 O 7-x with x ranging from ∼0 to 0.65 have been analyzed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) in the midinfrared region (400--6000 cm -1 ). Spectral line shapes vary gradually as a function of oxygen stoichiometry, and the reflectance at 400 and 1000 cm -1 decreases linearly with decreasing oxygen content. Spectra of samples that were incompletely synthesized or exposed to a 4% CO 2 atmosphere at 650 degree C clearly indicated the presence of carbonate. DRIFTS is therefore a quick, nondestructive method for determining oxygen content in YBa 2 Cu 3 O 7-x powders, and for detecting carbonate species due to synthesis error or reaction with CO 2 -bearing atmosphere

  13. The carbon dioxide content in ice cores - climatic curves of carbon dioxide. Zu den CO sub 2 -Klimakurven aus Eisbohrkernen

    Energy Technology Data Exchange (ETDEWEB)

    Heyke, H.E.

    1992-05-01

    The 'greenhouse effect', which implies a temperature of 15 deg C as against -18 deg C, owes its effect to 80% from water (clouds and gaseous phase) and to 10% from carbon dioxide, besides other components. Whereas water is largely unaccounted for, carbon dioxide has been postulated as the main cause of anticipated climatic catastrophe. The carbon dioxide concentration in the atmosphere has risen presently to such levels that all previous figures seem to have been left far behind. The reference point is the concentration of carbon dioxide in the air bubbles trapped in ice cores of Antartic and Greenland ice dated 160 000 years ago, which show much lower values than at present. A review of the most relevant publications indicates that many basic laws of chemistry seem to have been left largely unconsidered and experimental errors have made the results rather doubtful. Appropriate arguments have been presented. The investigations considered should be repeated under improved and more careful conditions. (orig.).

  14. Revision of Fontes & Garnier's model for the initial 14C content of dissolved inorganic carbon used in groundwater dating

    Science.gov (United States)

    Han, Liang-Feng; Plummer, Niel

    2013-01-01

    The widely applied model for groundwater dating using 14C proposed by Fontes and Garnier (F&G) (Fontes and Garnier, 1979) estimates the initial 14C content in waters from carbonate-rock aquifers affected by isotopic exchange. Usually, the model of F&G is applied in one of two ways: (1) using a single 13C fractionation factor of gaseous CO2 with respect to a solid carbonate mineral, εg/s, regardless of whether the carbon isotopic exchange is controlled by soil CO2 in the unsaturated zone, or by solid carbonate mineral in the saturated zone; or (2) using different fractionation factors if the exchange process is dominated by soil CO2 gas as opposed to solid carbonate mineral (typically calcite). An analysis of the F&G model shows an inadequate conceptualization, resulting in underestimation of the initial 14C values (14C0) for groundwater systems that have undergone isotopic exchange. The degree to which the 14C0 is underestimated increases with the extent of isotopic exchange. Examples show that in extreme cases, the error in calculated adjusted initial 14C values can be more than 20% modern carbon (pmc). A model is derived that revises the mass balance method of F&G by using a modified model conceptualization. The derivation yields a “global” model both for carbon isotopic exchange dominated by gaseous CO2 in the unsaturated zone, and for carbon isotopic exchange dominated by solid carbonate mineral in the saturated zone. However, the revised model requires different parameters for exchange dominated by gaseous CO2 as opposed to exchange dominated by solid carbonate minerals. The revised model for exchange dominated by gaseous CO2 is shown to be identical to the model of Mook (Mook, 1976). For groundwater systems where exchange occurs both in the unsaturated zone and saturated zone, the revised model can still be used; however, 14C0 will be slightly underestimated. Finally, in carbonate systems undergoing complex geochemical reactions, such as oxidation of

  15. Effect of the hypo and hyperstoichiometry of niobium about the solidification of steel with medium carbon content

    International Nuclear Information System (INIS)

    Kestenbach, H.-J.; Rodrigues, J.A.; Makray, E.T.

    1984-01-01

    The solidification sequency and the microstructure from carbon steel with 0.4%C and several content of Nb were investigated. Additions between 1 and 5% in Nb weight to obtain compositions hypo and hyperstoichiometric in relation to the niobium carbide formation were used. The metallographic observations were interpreted based in several solidifications reactions that could be occur in the iron rich region of the ternary diagram Fe-Nb-C. (E.G.) [pt

  16. Effects of retained austenite volume fraction, morphology, and carbon content on strength and ductility of nanostructured TRIP-assisted steels

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y.F., E-mail: shenyf@smm.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (MOE), Northeastern University, 3 Wenhua Road, Shenyang 110004 (China); Qiu, L.N. [Key Laboratory for Anisotropy and Texture of Materials (MOE), Northeastern University, 3 Wenhua Road, Shenyang 110004 (China); Sun, X. [Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352 (United States); Zuo, L. [Key Laboratory for Anisotropy and Texture of Materials (MOE), Northeastern University, 3 Wenhua Road, Shenyang 110004 (China); Liaw, P.K. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Raabe, D. [Max-Planck-Institut fuer Eisenforschung, Max-Planck-Str. 1, 8, 40237 Düsseldorf (Germany)

    2015-06-11

    With a suite of multi-modal and multi-scale characterization techniques, the present study unambiguously proves that a substantially-improved combination of ultrahigh strength and good ductility can be achieved by tailoring the volume fraction, morphology, and carbon content of the retained austenite (RA) in a transformation-induced-plasticity (TRIP) steel with the nominal chemical composition of 0.19C–0.30Si–1.76Mn–1.52Al (weight percent, wt%). After intercritical annealing and bainitic holding, a combination of ultimate tensile strength (UTS) of 1100 MPa and true strain of 50% has been obtained, as a result of the ultrafine RA lamellae, which are alternately arranged in the bainitic ferrite around junction regions of ferrite grains. For reference, specimens with a blocky RA, prepared without the bainitic holding, yield a low ductility (35%) and a low UTS (800 MPa). The volume fraction, morphology, and carbon content of RA have been characterized using various techniques, including the magnetic probing, scanning electron microscopy (SEM), electron-backscatter-diffraction (EBSD), and transmission electron microscopy (TEM). Interrupted tensile tests, mapped using EBSD in conjunction with the kernel average misorientation (KAM) analysis, reveal that the lamellar RA is the governing microstructure component responsible for the higher mechanical stability, compared to the blocky one. By coupling these various techniques, we quantitatively demonstrate that in addition to the RA volume fraction, its morphology and carbon content are equally important in optimizing the strength and ductility of TRIP-assisted steels.

  17. Fossil Microorganisms in Archaean

    Science.gov (United States)

    Astafleva, Marina; Hoover, Richard; Rozanov, Alexei; Vrevskiy, A.

    2006-01-01

    Ancient Archean and Proterozoic rocks are the model objects for investigation of rocks comprising astromaterials. The first of Archean fossil microorganisms from Baltic shield have been reported at the last SPIE Conference in 2005. Since this confeence biomorphic structures have been revealed in Archean rocks of Karelia. It was determined that there are 3 types of such bion structures: 1. structures found in situ, in other words microorganisms even-aged with rock matrix, that is real Archean fossils biomorphic structures, that is to say forms inhabited early formed rocks, and 3. younger than Archean-Protherozoic minerali microorganisms, that is later contamination. We made attempt to differentiate these 3 types of findings and tried to understand of burial of microorganisms. The structures belongs (from our point of view) to the first type, or real Archean, forms were under examination. Practical investigation of ancient microorganisms from Green-Stone-Belt of Northern Karelia turns to be very perspective. It shows that even in such ancient time as Archean ancient diverse world existed. Moreover probably such relatively highly organized cyanobacteria and perhaps eukaryotic formes existed in Archean world.

  18. Social Network and Content Analysis of the North American Carbon Program as a Scientific Community of Practice

    Science.gov (United States)

    Brown, Molly E.; Ihli, Monica; Hendrick, Oscar; Delgado-Arias, Sabrina; Escobar, Vanessa M.; Griffith, Peter

    2015-01-01

    The North American Carbon Program (NACP) was formed to further the scientific understanding of sources, sinks, and stocks of carbon in Earth's environment. Carbon cycle science integrates multidisciplinary research, providing decision-support information for managing climate and carbon-related change across multiple sectors of society. This investigation uses the conceptual framework of com-munities of practice (CoP) to explore the role that the NACP has played in connecting researchers into a carbon cycle knowledge network, and in enabling them to conduct physical science that includes ideas from social science. A CoP describes the communities formed when people consistently engage in shared communication and activities toward a common passion or learning goal. We apply the CoP model by using keyword analysis of abstracts from scientific publications to analyze the research outputs of the NACP in terms of its knowledge domain. We also construct a co-authorship network from the publications of core NACP members, describe the structure and social pathways within the community. Results of the content analysis indicate that the NACP community of practice has substantially expanded its research on human and social impacts on the carbon cycle, contributing to a better understanding of how human and physical processes interact with one another. Results of the co-authorship social network analysis demonstrate that the NACP has formed a tightly connected community with many social pathways through which knowledge may flow, and that it has also expanded its network of institutions involved in carbon cycle research over the past seven years.

  19. Dynamic carbon content as an indicator of desertification processes in soils developed from volcanic parental material in the Region of Murcia

    International Nuclear Information System (INIS)

    Martinez-Martinez, S.; Faz Cano, A.; Acosta Aviles, J. A.

    2009-01-01

    Soil Organic Carbon (SOC is an essential components of the global carbon cycle, especially in soils developed from volcanic rocks, due to these soils does not have inorganic carbon. In arid and semiarid areas mineralization of organic carbon is very intense due to climatic conditions, causing soils depletion and therefore desertification. The objective of this study is to determine the content of OC, as a first step in the assessment of desertification. The objective of this study is to determine the content of OC, as a first step in the assessment of desertification processes affecting this area of the southeast of Spain. (Author) 7 refs.

  20. Immediate analysis of the oil content of seeds by carbon-13 nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Leal, K Z; Costa, V E.U.; Seidl, P R; Campos, M P.A.; Colnago, L A [Instituto Militar de Engenharia, Rio de Janeiro (Brazil). Secao de Quimica

    1981-11-01

    The carbon 13 nuclear magnetic resonance (CMR) spectra of a series of Brazilian oilseeds was registered. The main constituents of the oils are identified and signals for each carbon atom are assigned. Chemical shifts are estimated for the free fatty acids and compared to those observed from the seeds, with good results. Besides being non-destructive, the RMC method proves to be fast and is useful in the determination of the principal components of the oil fraction of different types of seeds.

  1. Calcium content of different compositions of gallstones and pathogenesis of calcium carbonate gallstones

    Directory of Open Access Journals (Sweden)

    Ji-Kuen Yu

    2013-01-01

    Conclusion: From our study, we found chronic and/or intermittent cystic duct obstructions and low-grade GB wall inflammation lead to GB epithelium hydrogen secretion dysfunction. Increased calcium ion efflux into the GB lumen combined with increased carbonate anion presence increases SI_CaCO3 from 1 to 22.4. Thus, in an alkaline milieu with pH 7.8, calcium carbonate begins to aggregate and precipitate.

  2. Mineralogy of Non-Silicified Fossil Wood

    Directory of Open Access Journals (Sweden)

    George E. Mustoe

    2018-03-01

    Full Text Available The best-known and most-studied petrified wood specimens are those that are mineralized with polymorphs of silica: opal-A, opal-C, chalcedony, and quartz. Less familiar are fossil woods preserved with non-silica minerals. This report reviews discoveries of woods mineralized with calcium carbonate, calcium phosphate, various iron and copper minerals, manganese oxide, fluorite, barite, natrolite, and smectite clay. Regardless of composition, the processes of mineralization involve the same factors: availability of dissolved elements, pH, Eh, and burial temperature. Permeability of the wood and anatomical features also plays important roles in determining mineralization. When precipitation occurs in several episodes, fossil wood may have complex mineralogy.

  3. Diatoms: a fossil fuel of the future.

    Science.gov (United States)

    Levitan, Orly; Dinamarca, Jorge; Hochman, Gal; Falkowski, Paul G

    2014-03-01

    Long-term global climate change, caused by burning petroleum and other fossil fuels, has motivated an urgent need to develop renewable, carbon-neutral, economically viable alternatives to displace petroleum using existing infrastructure. Algal feedstocks are promising candidate replacements as a 'drop-in' fuel. Here, we focus on a specific algal taxon, diatoms, to become the fossil fuel of the future. We summarize past attempts to obtain suitable diatom strains, propose future directions for their genetic manipulation, and offer biotechnological pathways to improve yield. We calculate that the yields obtained by using diatoms as a production platform are theoretically sufficient to satisfy the total oil consumption of the US, using between 3 and 5% of its land area. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Fossil Energy Planning for Navajo Nation

    Energy Technology Data Exchange (ETDEWEB)

    Acedo, Margarita [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-11

    This project includes fossil energy transition planning to find optimal solutions that benefit the Navajo Nation and stakeholders. The majority of the tribe’s budget currently comes from fossil energy-revenue. The purpose of this work is to assess potential alternative energy resources including solar photovoltaics and biomass (microalgae for either biofuel or food consumption). This includes evaluating carbon-based reserves related to the tribe’s resources including CO2 emissions for the Four Corners generating station. The methodology for this analysis will consist of data collection from publicly available data, utilizing expertise from national laboratories and academics, and evaluating economic, health, and environmental impacts. Finally, this report will highlight areas of opportunities to implement renewable energy in the Navajo Nation by presenting the technology requirements, cost, and considerations to energy, water, and environment in an educational structure.

  5. A Raman Study of Carbonates and Organic Contents in Five CM Chondrites

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.; Bodnar, R. J.; Farley, C.; Cheung, J. C. H.

    2016-01-01

    Carbonates comprise the second most abundant class of carbon-bearing phases in carbonaceous chondrites after organic matter (approximately 2 wt.%), followed by other C-bearing phases such as diamond, silicon carbide, and graphite. Therefore, understanding the abundances of carbonates and the associated organic matter provide critical insight into the genesis of major carbonaceous components in chondritic materials. Carbonates in CM chondrites mostly occur as calcite (of varying composition) and dolomite. Properly performed, Raman spectroscopy provides a non-destructive technique for characterizing meteorite mineralogy and organic chemistry. It is sensitive to many carbonaceous phases, allows the differentiation of organic from inorganic materials, and the interpretation of their spatial distribution. Here, with the use of Raman spectroscopy, we determine the structure of the insoluble organic matter (IOM) in the matrix and carbonate phases in five CM chondrites: Jbilet Winselwan, Murchison, Nogoya, Santa Cruz, and Wisconsin Range (WIS) 91600, and interpret the relative timing of carbonate precipitation and the extent of the associated alteration events.

  6. Carbon and nutrient contents in soils from the Kings River Experimental Watersheds, Sierra Nevada Mountains, California

    Science.gov (United States)

    D.W. Johnson; C.T. Hunsaker; D.W. Glass; B.M. Rau; B.A. Roath

    2011-01-01

    Soil C and nutrient contents were estimated for eight watersheds in two sites (one high elevation, Bull, and one low elevation, Providence) in the Kings River Experimental Watersheds in the western Sierra Nevada Mountains of California. Eighty-seven quantitative pits were dug to measure soil bulk density and total rock content, while three replicate surface samples...

  7. ESR dating studies on fossil of elaphurus davidianus horn

    International Nuclear Information System (INIS)

    Chen Shiming; Wang Hong; Tang Jingjuan; Yan Xiaomin; Guo Shiqing

    1991-01-01

    On the basis of studies on elephant tooth fossil, ESR dating of elaphurus davidianus horn fossil found in Anhui Province was reported. The sample examined by TEM electron spectrum is composed of hydroxyapatite. ESR experiments showed that the solid bone sample can be chosen as dating material. According to the contents of U, Th and K in the sample determined by ICP, the annual dose of radiation was calculated by using the linear uranium accumulation model and disequilibrium decay. The age of this fossil was determined to be 2.5 x 10 4 years

  8. Radioactivity in fossils at the Hagerman Fossil Beds National Monument.

    Science.gov (United States)

    Farmer, C Neal; Kathren, Ronald L; Christensen, Craig

    2008-08-01

    Since 1996, higher than background levels of naturally occurring radioactivity have been documented in both fossil and mineral deposits at Hagerman Fossil Beds National Monument in south-central Idaho. Radioactive fossil sites occur primarily within an elevation zone of 900-1000 m above sea level and are most commonly found associated with ancient river channels filled with sand. Fossils found in clay rich deposits do not exhibit discernable levels of radioactivity. Out of 300 randomly selected fossils, approximately three-fourths exhibit detectable levels of natural radioactivity ranging from 1 to 2 orders of magnitude above ambient background levels when surveyed with a portable hand held Geiger-Muller survey instrument. Mineral deposits in geologic strata also show above ambient background levels of radioactivity. Radiochemical lab analysis has documented the presence of numerous natural radioactive isotopes. It is postulated that ancient groundwater transported radioactive elements through sand bodies containing fossils which precipitated out of solution during the fossilization process. The elevated levels of natural radioactivity in fossils may require special precautions to ensure that exposures to personnel from stored or displayed items are kept as low as reasonably achievable (ALARA).

  9. Electrochemical Glucose Oxidation Using Glassy Carbon Electrodes Modified with Au-Ag Nanoparticles: Influence of Ag Content

    Directory of Open Access Journals (Sweden)

    Nancy Gabriela García-Morales

    2015-01-01

    Full Text Available This paper describes the application of glassy carbon modified electrodes bearing Aux-Agy nanoparticles to catalyze the electrochemical oxidation of glucose. In particular, the paper shows the influence of the Ag content on this oxidation process. A simple method was applied to prepare the nanoparticles, which were characterized by transmission electron microscopy, Ultraviolet-Visible spectroscopy, X-ray diffraction spectroscopy, and cyclic voltammetry. These nanoparticles were used to modify glassy carbon electrodes. The effectiveness of these electrodes for electrochemical glucose oxidation was evaluated. The modified glassy carbon electrodes are highly sensitive to glucose oxidation in alkaline media, which could be attributed to the presence of Aux-Agy nanoparticles on the electrode surface. The voltammetric results suggest that the glucose oxidation speed is controlled by the glucose diffusion to the electrode surface. These results also show that the catalytic activity of the electrodes depends on the Ag content of the nanoparticles. Best results were obtained for the Au80-Ag20 nanoparticles modified electrode. This electrode could be used for Gluconic acid (GA production.

  10. Morphology, Microstructure, and Hydrogen Content of Carbon Nanostructures Obtained by PECVD at Various Temperatures

    Directory of Open Access Journals (Sweden)

    M. Acosta Gentoiu

    2017-01-01

    Full Text Available Carbon nanostructures were obtained by acetylene injection into an argon plasma jet in the presence of hydrogen. The samples were synthesized in similar conditions, except that the substrate deposition temperatures TD were varied, ranging from 473 to 973 K. A strong dependence of morphology, structure, and graphitization upon TD was found. We obtained vertical aligned carbon nanotubes (VA-CNTs at low temperatures as 473 K, amorphous carbon nanoparticles (CNPs at temperatures from about 573 to 673 K, and carbon nanowalls (CNWs at high temperatures from 773 to 973 K. Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, elastic recoil detection analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy were used to substantiate the differences in these material types. It is known that hydrogen concentration modifies strongly the properties of the materials. Different concentrations of hydrogen-bonded carbon could be identified in amorphous CNP, VA-CNT, and CNW. Also, the H : C ratios along depth were determined for the obtained materials.

  11. Controllable synthesis of carbon nanotubes by changing the Mo content in bimetallic Fe-Mo/MgO catalyst

    International Nuclear Information System (INIS)

    Xu Xiangju; Huang Shaoming; Yang Zhi; Zou Chao; Jiang Junfan; Shang Zhijie

    2011-01-01

    Research highlights: → Increasing the Mo content in the Fe-Mo/MgO catalysts resulted in an increase in wall number, diameter and growth yield of carbon nanotubes. → The Fe interacts with MgO to form complex (MgO) x (FeO) 1-x (0 4 and relative large metal Mo particles can be generated after reduction. → The avalanche-like reduction of MgMoO 4 makes the catalyst particles to be small thus enhances the utilize efficiency of Fe nanoparticles. - Abstract: A series of Fe-Mo/MgO catalysts with different Mo content were prepared by combustion method and used as catalysts for carbon nanotube (CNT) growth. Transmission electron microscopy studies of the nanotubes show that the number of the CNT walls and the CNT diameters increase with the increasing of Mo content in the bimetallic catalyst. The growth yield determined by thermogravimetric analysis also follows the trend: the higher the Mo content, the higher the yield of the CNTs. However, the increase of Mo content leads to the lower degree of graphitization of CNTs. A comparative study on the morphology and catalytic functions of Fe/MgO, Mo/MgO and Fe-Mo/MgO catalysts was carried out by scanning electron microscopy and X-ray diffraction. It is found that the Fe interacts with MgO to form complexes and is then dispersed into the MgO support uniformly, resulting in very small Fe nanoparticles after reduction. The Mo interacts with MgO to form stoichiometry compound MgMoO 4 and relative large metal Mo particles can be generated after reduction. High yield CNTs with small diameter can be generated from Fe-Mo/MgO because the avalanche-like reduction of MgMoO 4 makes the catalyst particles to be small thus enhances the utilize efficiency of Fe nanoparticles.

  12. Emissions Scenarios and Fossil-fuel Peaking

    Science.gov (United States)

    Brecha, R.

    2008-12-01

    Intergovernmental Panel on Climate Change (IPCC) emissions scenarios are based on detailed energy system models in which demographics, technology and economics are used to generate projections of future world energy consumption, and therefore, of greenhouse gas emissions. Built into the assumptions for these scenarios are estimates for ultimately recoverable resources of various fossil fuels. There is a growing chorus of critics who believe that the true extent of recoverable fossil resources is much smaller than the amounts taken as a baseline for the IPCC scenarios. In a climate optimist camp are those who contend that "peak oil" will lead to a switch to renewable energy sources, while others point out that high prices for oil caused by supply limitations could very well lead to a transition to liquid fuels that actually increase total carbon emissions. We examine a third scenario in which high energy prices, which are correlated with increasing infrastructure, exploration and development costs, conspire to limit the potential for making a switch to coal or natural gas for liquid fuels. In addition, the same increasing costs limit the potential for expansion of tar sand and shale oil recovery. In our qualitative model of the energy system, backed by data from short- and medium-term trends, we have a useful way to gain a sense of potential carbon emission bounds. A bound for 21st century emissions is investigated based on two assumptions: first, that extractable fossil-fuel resources follow the trends assumed by "peak oil" adherents, and second, that little is done in the way of climate mitigation policies. If resources, and perhaps more importantly, extraction rates, of fossil fuels are limited compared to assumptions in the emissions scenarios, a situation can arise in which emissions are supply-driven. However, we show that even in this "peak fossil-fuel" limit, carbon emissions are high enough to surpass 550 ppm or 2°C climate protection guardrails. Some

  13. Equation of State of Fe3C and Implications for the Carbon Content of Earth's Core

    Science.gov (United States)

    Davis, A.; Brauser, N.; Thompson, E. C.; Chidester, B.; Greenberg, E.; Prakapenka, V. B.; Campbell, A.

    2017-12-01

    Carbon is a common component in protoplanetary cores, as represented by iron meteorites. Therefore, along with silicon, oxygen, and other light elements, it is likely to be an alloying component with iron in Earth's core. Previous studies of the densities of iron carbides have not reached the combined pressure and temperature conditions relevant to Earth's core. To better understand the geophysical implications of carbon addition to Earth's core, we report P-V-T measurements of Fe3C to pressures and temperatures exceeding 110 GPa and 2500 K, using synchrotron X-ray diffraction in a laser heated diamond anvil cell. Fitting these measurements to an equation of state and assuming 1.5% density change upon melting and a 4000 K core-mantle boundary temperature, we report a value of 6 wt% carbon necessary to match the PREM density in the outer core. This value should be considered an upper bound due to the likely presence of other light elements.

  14. Coupled Land Surface-Subsurface Hydrogeophysical Inverse Modeling to Estimate Soil Organic Carbon Content in an Arctic Tundra

    Science.gov (United States)

    Tran, A. P.; Dafflon, B.; Hubbard, S.

    2017-12-01

    Soil organic carbon (SOC) is crucial for predicting carbon climate feedbacks in the vulnerable organic-rich Arctic region. However, it is challenging to achieve this property due to the general limitations of conventional core sampling and analysis methods. In this study, we develop an inversion scheme that uses single or multiple datasets, including soil liquid water content, temperature and ERT data, to estimate the vertical profile of SOC content. Our approach relies on the fact that SOC content strongly influences soil hydrological-thermal parameters, and therefore, indirectly controls the spatiotemporal dynamics of soil liquid water content, temperature and their correlated electrical resistivity. The scheme includes several advantages. First, this is the first time SOC content is estimated by using a coupled hydrogeophysical inversion. Second, by using the Community Land Model, we can account for the land surface dynamics (evapotranspiration, snow accumulation and melting) and ice/liquid phase transition. Third, we combine a deterministic and an adaptive Markov chain Monte Carlo optimization algorithm to better estimate the posterior distributions of desired model parameters. Finally, the simulated subsurface variables are explicitly linked to soil electrical resistivity via petrophysical and geophysical models. We validate the developed scheme using synthetic experiments. The results show that compared to inversion of single dataset, joint inversion of these datasets significantly reduces parameter uncertainty. The joint inversion approach is able to estimate SOC content within the shallow active layer with high reliability. Next, we apply the scheme to estimate OC content along an intensive ERT transect in Barrow, Alaska using multiple datasets acquired in the 2013-2015 period. The preliminary results show a good agreement between modeled and measured soil temperature, thaw layer thickness and electrical resistivity. The accuracy of estimated SOC content

  15. Immediate analysis of the oil content of seeds by carbon-13 nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Leal, K.Z.; Costa, V.E.U.; Seidl, P.R.; Campos, M.P.A.; Colnago, L.A.

    1981-01-01

    The carbon 13 nuclear magnetic resonance (CMR) spectra of a series of Brazilian oilseeds was registered. The main constituents of the oils are identified and signals for each carbon atom are assigned. Chemical shifts are estimated for the free fatty acids and compared to those observed from the seeds, with good results. Besides being non-destructive, the RMC method proves to be fast and is useful in the determination of the principal components of the oil fraction of different types of seeds. (Author) [pt

  16. Electrochemical Determination of Caffeine Content in Ethiopian Coffee Samples Using Lignin Modified Glassy Carbon Electrode

    OpenAIRE

    Amare, Meareg; Aklog, Senait

    2017-01-01

    Lignin film was deposited at the surface of glassy carbon electrode potentiostatically. In contrast to the unmodified glassy carbon electrode, an oxidative peak with an improved current and overpotential for caffeine at modified electrode showed catalytic activity of the modifier towards oxidation of caffeine. Linear dependence of peak current on caffeine concentration in the range 6 ? 10?6 to 100 ? 10?6?mol?L?1 with determination coefficient and method detection limit (LoD = 3?s/slope) of 0....

  17. The Effect Of Carbon Concentration On The Retained Austenite Content And The Mechanical Properties Of TRIP Steel Wire Rod Obtained From The Stelmor Controlled Cooling Line

    Directory of Open Access Journals (Sweden)

    Muskalski Z.

    2015-09-01

    Full Text Available The austenite content of the multiphase TRIP-structure steels depends, inter alia, on the carbon concentration and the properly selected parameters of the two-stage heat treatment.

  18. Effect of carbonate content on the mechanical behaviour of clay fault-gouges

    Science.gov (United States)

    Bakker, Elisenda; Niemeijer, André; Hangx, Suzanne; Spiers, Chris

    2015-04-01

    Carbon dioxide capture and storage (CCS) in depleted oil and gas reservoirs is considered to be the most promising technology to achieve large-scale reduction in anthropogenic emissions. In order to retain the stored CO2 from the atmosphere for the very long-term, i.e. on timescales of the order of 103-104 years, it is essential to maintain the integrity of the caprock, and more specifically of any faults penetrating the seal. When selecting suitable CO2-storage reservoirs, pre-exisiting faults within the caprock require close attention, as changes in the stress state resulting from CO2-injection may induce fault slip motion which might cause leakage. Little is known about the effect of fluid-rock interactions on the mineral composition, mechanical properties and the integrity and sealing capacity of the caprock. Previous studies on the effect of mineral composition on the frictional properties of fault gouges have shown that friction is controlled by the dominant phase unless there is a frictionally weak, through-going fabric. However, the effect on stability is less clear. Since long-term CO2-exposure might cause chemical reactions, potentially resulting in the dissolution or precipitation of carbonate minerals, a change in mineralogy could affect the mechanical stability of a caprock significantly. Calcite, for example, is known to be prone to micro-seismicity and shows a transition from velocity-strengthening to velocity-weakening behaviour around 100-150°C. Therefore, we investigated the effect of varying clay:carbonate ratios on fault friction behaviour, fault reactivation potential and slip stability, i.e. seismic vs. aseismic behaviour. Three types of simulated fault gouges were used: i) carbonate-free, natural clay-rich caprock samples, consisting of predominantly phyllosilicates (~80%) and quartz ~20%), ii) pure calcite, and iii) mixtures of carbonate-free clay-rich caprock and pure calcite, with predetermined clay:carbonate ratios. For the natural clay

  19. First fossil insectivores from Flores

    NARCIS (Netherlands)

    Hoek Ostende, van den L.W.; Berch, van der G.; Awe Due, R.

    2006-01-01

    The hominid bearing strata from the Liang Bua cave on Flores have yielded a large amount of microvertebrate remains. Among these are three mandibles of shrews, the first record of fossil insectivores from the island. The fossils, representing two different species, are not referable to any of the

  20. The role of fossil organic matter in the ecosystem development of post-mining sites revealed by isotope analyses

    Science.gov (United States)

    Jandova, Katerina; Hyodo, Fujio; Vindušková, Olga; Moradi, Jabbar; Frouz, Jan

    2017-04-01

    Sediments rich in kerogen ( 19 Ma old, 14C-free) are present in the overburden at post-mining area in Western Bohemia, near Sokolov city, the Czech Republic. There are two successional chronosequences, an alder reclamation and spontaneous succession, consisting of sites that differ in time since heaping. Both chronosequences accumulate recent organic matter over time, although the process is initially faster at reclamation. We hypothesized that (i) radiocarbon age of soil organic matter would be decreasing with time since spoil heaping; (ii) the detrital food web would show the assimilation of fossil carbon by heterotrophic organisms in the initial stages of succession when fossil organic matter is the predominant source of carbon; (iii) the isotopic track of fossil organic matter in the detrital food web would be more prominent at sites with lower vegetation cover and litter production. Nitrogen isotopic ratios of soils were high at the young sites and the decrease in δ15N was correlated with the increase in content of recent organic carbon. Nitrogen isotopic ratios of soil detritivores equalled to that of tree leaves at reclamation but were higher at successional sites. Possibly, other food sources were used apart from tree leaves litter at the latter. Interestingly, soil animals but not primary producers were 14C depleted in the youngest relative to the oldest sites. The depletion in 14C of detritivores relative to primary producers was likely due to the geophagy behaviour of the millipedes at the young sites where fossil organic matter is the largest carbon pool.

  1. The global distribution of leaf chlorophyll content and seasonal controls on carbon uptake

    Science.gov (United States)

    Croft, H.; Chen, J. M.; Luo, X.; Bartlett, P. A.; Staebler, R. M.; He, L.; Mo, G.; Luo, S.; Simic, A.; Arabian, J.; He, Y.; Zhang, Y.; Beringer, J.; Hutley, L. B.; Noland, T. L.; Arellano, P.; Stahl, C.; Homolová, L.; Bonal, D.; Malenovský, Z.; Yi, Q.; Amiri, R.

    2017-12-01

    Leaf chlorophyll (ChlLeaf) is crucial to biosphere-atmosphere exchanges of carbon and water, and the functioning of terrestrial ecosystems. Improving the accuracy of modelled photosynthetic carbon uptake is a central priority for understanding ecosystem response to a changing climate. A source of uncertainty within gross primary productivity (GPP) estimates is the failure to explicitly consider seasonal controls on leaf photosynthetic potential. Whilst the inclusion of ChlLeafinto carbon models has shown potential to provide a physiological constraint, progress has been hampered by the absence of a spatially-gridded, global chlorophyll product. Here, we present the first spatially-continuous, global view of terrestrial ChlLeaf, at weekly intervals. Satellite-derived ChlLeaf was modelled using a physically-based radiative transfer modelling approach, with a two stage model inversion method. 4-Scale and SAIL canopy models were first used to model leaf-level reflectance from ENIVSAT MERIS 300m satellite data. The PROSPECT leaf model was then used to derive ChlLeaf from the modelled leaf reflectance. This algorithm was validated using measured ChlLeaf data from 248 measurements within 26 field locations, covering six plant functional types (PFTs). Modelled results show very good relationships with measured data, particularly for deciduous broadleaf forests (R2 = 0.67; pmake an important step towards improving the accuracy of global carbon budgets.

  2. Linking organic carbon, water content and nitrous oxide emission in a reclaimed coal mine soil

    Science.gov (United States)

    Manure-based organic amendments can restore soil quality and allow for intensive sustained biomass production on degraded lands. However the large quantities of nitrogen and organic carbon added with such amendments could create soil conditions favorable for nitrous oxide production and emissions. T...

  3. A review of volatile compounds in tektites, and carbon content and isotopic composition of moldavite glass

    Czech Academy of Sciences Publication Activity Database

    Žák, Karel; Skála, Roman; Řanda, Zdeněk; Mizera, Jiří

    2012-01-01

    Roč. 47, č. 6 (2012), s. 1010-1028 ISSN 1086-9379 R&D Projects: GA ČR GA205/09/0991 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z10480505 Keywords : moldavites * geochemistry * ries * carbon stable isotopes * moldavites (Germany) Subject RIV: DD - Geochemistry Impact factor: 2.800, year: 2012

  4. Fossil fuel furnace reactor

    Science.gov (United States)

    Parkinson, William J.

    1987-01-01

    A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.

  5. Clean fossil-fuelled power generation

    International Nuclear Information System (INIS)

    Oliver, Tony

    2008-01-01

    Using fossil fuels is likely to remain the dominant means of producing electricity in 2030 and even 2050, partly because power stations have long lives. There are two main ways of reducing CO 2 emissions from fossil-fuelled power plants. These are carbon capture and storage (CCS), which can produce near-zero CO 2 emissions, and increases in plant efficiency, which can give rise to significant reductions in CO 2 emissions and to reduced costs. If a typical UK coal-fired plant was replaced by today's best available technology, it would lead to reductions of around 25% in emissions of CO 2 per MW h of electricity produced. Future technologies are targeting even larger reductions in emissions, as well as providing a route, with CCS, to zero emissions. These two routes are linked and they are both essential activities on the pathway to zero emissions. This paper focuses on the second route and also covers an additional third route for reducing emissions, the use of biomass. It discusses the current status of the science and technologies for fossil-fuelled power generation and outlines likely future technologies, development targets and timescales. This is followed by a description of the scientific and technological developments that are needed to meet these challenges. Once built, a power plant can last for over 40 years, so the ability to upgrade and retrofit a plant during its lifetime is important

  6. Microwave absorbing properties of polyaniline/multi-walled carbon nanotube composites with various polyaniline contents

    International Nuclear Information System (INIS)

    Ting, T.H.; Jau, Y.N.; Yu, R.P.

    2012-01-01

    Polyaniline/multi-walled carbon nanotube (PANI/MWNT) composites were synthesized using in situ polymerization at different aniline/multi-walled carbon nanotube weight ratios (Ani/MWNT = 1/2, 1/1, 2/1 and 3/1) and introduced into an epoxy resin to act as a microwave absorber. The spectroscopic characterization of the process of formation of PANI/MWNT composites were studied using Fourier transform infrared spectroscopy, an ultraviolet-visible spectrophotometer, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron spin resonance. The microwave absorbing properties were investigated by measuring complex permittivity, complex permeability and reflection loss in the 2-18 and 18-40 GHz microwave frequency range, using the free space method. The results showed that the addition of PANI was useful for achieving a large absorption over a wide frequency range, especially for higher frequency values.

  7. Fructose content and composition of commercial HFCS-sweetened carbonated beverages.

    Science.gov (United States)

    White, J S; Hobbs, L J; Fernandez, S

    2015-01-01

    The obesigenic and related health effects of caloric sweeteners are subjects of much current research. Consumers can properly adjust their diets to conform to nutritional recommendations only if the sugars composition of foods and beverages is accurately measured and reported, a matter of recent concern. We tested the hypothesis that high-fructose corn syrup (HFCS) used in commercial carbonated beverages conforms to commonly assumed fructose percentages and industry technical specifications, and fulfills beverage product label regulations and Food Chemicals Codex-stipulated standards. A high-pressure liquid chromatography method was developed and verified for analysis of sugars in carbonated beverages sweetened with HFCS-55. The method was used to measure percent fructose in three carbonated beverage categories. Method verification was demonstrated by acceptable linearity (R(2)>0.99), accuracy (94-104% recovery) and precision (RSD canned and bottled products and met the US Federal requirements for nutritional labeling and nutrient claims. Prior concerns about composition were likely owing to use of improper and unverified methodology.

  8. Austria's CO2 responsibility and the carbon content of its international trade

    International Nuclear Information System (INIS)

    Munoz, Pablo; Steininger, Karl W.

    2010-01-01

    Seeking to limit global warming to 2 C puts narrow restrictions on the remaining carbon budget. While the prevalent accounting framework for carbon emissions is production based (Production-Based Principle, PBP), we here quantify the CO 2 emissions on the basis of the Consumption-Based Principle (CBP) for Austria. At a methodological level, a Multi-Regional Input-Output model with full linkages is used to account for Austria's CO 2 responsibility on a global scale. Estimates are carried out for the years 1997 and 2004. Results show that during 1997 CO 2 responsibility based on CBP were 36% larger than those based on PBP. This relation has increased through time. The CBP indicator of 2004 was 44% larger than the PBP. In terms of carbon emission location, for each Euro spent on Austrian final demand in 2004, it is estimated that two-thirds of the CO 2 emissions occur outside Austrian borders. Regarding the origin of the emissions embodied in imports, it is estimated that about one-fourth originated in non-Annex I countries in 1997. This proportion increased to one-third by 2004. Due to this divergence between CBP and PBP indicators, there is a need to re-think current accounting bases in order to properly assign CO 2 responsibilities. (author)

  9. Carbon dioxide and future climate

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J M

    1977-03-01

    The addition of carbon dioxide to the atmosphere due to burning fossil fuel is discussed. The release rate of carbon dioxide has been growing since at least 1950 at an average rate of 4.3% per year. If all known fossil fuel reserves in the world are consumed, a total of between 5 and 14 times the present amount of carbon dioxide in the atmosphere will be released. The oceans would then be unlikely to withdraw the proportion of perhaps 40% which they are believed to have withdrawn up to the present. The increase in the atmosphere would be in excess of 3 times or conceivably ten times the present amount. If the reserves are used up within a few hundred years, more than half the excess carbon dioxide would remain in the atmosphere after a thousand years. The ''greenhouse'' effect of carbon dioxide is explained. The simulation with numerical models of the effects of carbon dioxide on atmospheric radiation fluxes is discussed. An estimated increase in the average annual temperature of the earth of 2.4 to 2.9C is given for doubling the carbon dioxide content; also a 7% increase in global average precipitation. The effect of increasing carbon dioxide on global mean temperature is viewed in the perspective of the glacial-interglacial cycles. The warming effect of carbon dioxide may induce a ''super-interglacial'' on the present interglacial which is expected to decline toward a new ice age in the next several thousand years. Finally it is proposed that it may be necessary to phase out the use of fossil fuels before all the knowledge is acquired which would necessitate such an action.

  10. International Student Carbon Footprint Challenge--Social Media as a Content and Language Integrated Learning Environment

    Science.gov (United States)

    Fauville, Géraldine; Lantz-Andersson, Annika; Säljö, Roger

    2012-01-01

    Environmental education (EE) is now clearly specified in educational standards in many parts of the world, and at the same time the view of language learning is moving towards a content and language integrated learning (CLIL) strategy, to make English lessons more relevant and attractive for students (Eurydice, 2006). In this respect,…

  11. The Oklo fossil reactor

    International Nuclear Information System (INIS)

    Roth, Etienne.

    1975-01-01

    From the observation of anomalous 235 U content of a UF 6 cylinder in Pierrelatte, it was possible to trace back this anomaly to minerals coming from the Oklo quarry in Gabon. Large variations in 235 U content such as were observed could only come from very specific processes, one of them being induced fission. To investigate this hypothesis it was looked for the fission rare earths and their isotopic composition, and these unequivocally assigned the phenomenon to a reaction of fission of 235 U [fr

  12. Voltammetric determination of polyphenolic content in pomegranate juice using a poly(gallic acid/multiwalled carbon nanotube modified electrode

    Directory of Open Access Journals (Sweden)

    Refat Abdel-Hamid

    2016-07-01

    Full Text Available A simple and sensitive poly(gallic acid/multiwalled carbon nanotube modified glassy carbon electrode (PGA/MWCNT/GCE electrochemical sensor was prepared for direct determination of the total phenolic content (TPC as gallic acid equivalent. The GCE working electrode was electrochemically modified and characterized using scanning electron microscope (SEM, cyclic voltammetry (CV, chronoamperometry and chronocoulometry. It was found that gallic acid (GA exhibits a superior electrochemical response on the PGA/MWCNT/GCE sensor in comparison with bare GCE. The results reveal that a PGA/MWCNT/GCE sensor can remarkably enhance the electro-oxidation signal of GA as well as shift the peak potentials towards less positive potential values. The dependence of peak current on accumulation potential, accumulation time and pH were investigated by square-wave voltammetry (SWV to optimize the experimental conditions for the determination of GA. Using the optimized conditions, the sensor responded linearly to a GA concentration throughout the range of 4.97 × 10−6 to 3.38 × 10−5 M with a detection limit of 3.22 × 10−6 M (S/N = 3. The fabricated sensor shows good selectivity, stability, repeatability and (101% recovery. The sensor was successfully utilized for the determination of total phenolic content in fresh pomegranate juice without interference of ascorbic acid, fructose, potassium nitrate and barbituric acid. The obtained data were compared with the standard Folin–Ciocalteu spectrophotometric results.

  13. Effects of carbon content on high-temperature mechanical and thermal fatigue properties of high-boron austenitic steels

    Directory of Open Access Journals (Sweden)

    Xiang Chen

    2016-01-01

    Full Text Available High-temperature mechanical properties of high-boron austenitic steels (HBASs were studied at 850 °C using a dynamic thermal-mechanical simulation testing machine. In addition, the thermal fatigue properties of the alloys were investigated using the self-restraint Uddeholm thermal fatigue test, during which the alloy specimens were cycled between room temperature and 800°C. Stereomicroscopy and scanning electron microscopy were used to study the surface cracks and cross-sectional microstructure of the alloy specimens after the thermal fatigue tests. The effects of carbon content on the mechanical properties at room temperature and high-temperature as well as thermal fatigue properties of the HBASs were also studied. The experimental results show that increasing carbon content induces changes in the microstructure and mechanical properties of the HBASs. The boride phase within the HBAS matrix exhibits a round and smooth morphology, and they are distributed in a discrete manner. The hardness of the alloys increases from 239 (0.19wt.% C to 302 (0.29wt.% C and 312 HV (0.37wt.% C; the tensile yield strength at 850 °C increases from 165.1 to 190.3 and 197.1 MPa; and the compressive yield strength increases from 166.1 to 167.9 and 184.4 MPa. The results of the thermal fatigue tests (performed for 300 cycles from room temperature to 800 °C indicate that the degree of thermal fatigue of the HBAS with 0.29wt.% C (rating of 2–3 is superior to those of the alloys with 0.19wt.% (rating of 4–5 and 0.37wt.% (rating of 3–4 carbon. The main cause of this difference is the ready precipitation of M23(C,B6-type borocarbides in the alloys with high carbon content during thermal fatigue testing. The precipitation and aggregation of borocarbide particles at the grain boundaries result in the deterioration of the thermal fatigue properties of the alloys.

  14. Physical properties and organic carbon content of a Rhodic Kandiudox fertilized with pig slurry and poultry litter

    Directory of Open Access Journals (Sweden)

    Luiz Paulo Rauber

    2012-08-01

    Full Text Available The impact of pig slurry and poultry litter fertilization on soils depends on the conditions of use and the amounts applied. This study evaluated the effect of organic fertilizers after different application periods in different areas on the physical properties and organic carbon contents of a Rhodic Kandiudox, in Concordia, Santa Catarina, in Southern Brazil. The treatments consisted of different land uses and periods of pig and poultry litter fertilization: silage maize (M7 years, silage maize (M20 years, annual ryegrass pasture (P3 years, annual ryegrass pasture (P15 years, perennial pasture (PP20 years, yerba mate tea (Mt20 years, native forest (NF, and native pasture without manure application (P0. The 0-5, 5-10 and 10-20 cm soil layers were sampled and analyzed for total organic carbon, total nitrogen and soil physical properties such as density, porosity, aggregation, degree of flocculation, and penetration resistance. The organic carbon levels in the cultivated areas treated with organic fertilizer were even lower than in native forest soil. The organic fertilizers and studied management systems reduced the flocculation degree of the clay particles, and low macroporosity was observed in some areas. Despite these changes, a good soil physical structure was maintained, e.g., soil density and resistance to penetration were below the critical limits, whereas aggregate stability was high, which is important to reduce water erosion in these areas with rugged terrain in western Santa Catarina, used for pig and poultry farming.

  15. Ash content, carbon and C/N ratio in paricá in function of NPK fertilization

    Directory of Open Access Journals (Sweden)

    CRISTIANE R. VIEIRA

    2018-02-01

    Full Text Available ABSTRACT Fertilization in areas of forest plantations is needed to supplement plants´ nutritional needs until harvest. An experiment was performed to check the influence of fertilization on levels of ash, carbon and C/N relation in Schizolobium amazonicum. Soil liming was performed and fertilization occurred after 15 days of incubation. S. amazonicum seedlings were produced and submitted to fertilization with N, P and K: N = 0, 40, 80 and 120 kg ha-1; P2O5 = 0, 50, 100 and 200 kg ha-1; K2O = 0, 50, 100 and 200 kg ha-1. The plants were measured after 180 days. The seedlings of 20 treatments with the highest increase in height and diameter were transplanted to the field. Soil was fertilized and limestone was spread; seedlings were distributed into randomized blocks, with six replications. After 12 months, the plants were removed to determine ash, organic carbon, C/N relation contents. The ashes were submitted to digestion to determine nutrient concentrations. Fertilization influenced the levels of ash and organic carbon and C/N relation in S. amazonicum. Results indicate that the species has a potential for energy production.

  16. Ash content, carbon and C/N ratio in paricá in function of NPK fertilization.

    Science.gov (United States)

    Vieira, Cristiane R; Weber, Oscarlina L S; Scaramuzza, José Fernando

    2018-01-01

    Fertilization in areas of forest plantations is needed to supplement plants´ nutritional needs until harvest. An experiment was performed to check the influence of fertilization on levels of ash, carbon and C/N relation in Schizolobium amazonicum. Soil liming was performed and fertilization occurred after 15 days of incubation. S. amazonicum seedlings were produced and submitted to fertilization with N, P and K: N = 0, 40, 80 and 120 kg ha-1; P2O5 = 0, 50, 100 and 200 kg ha-1; K2O = 0, 50, 100 and 200 kg ha-1. The plants were measured after 180 days. The seedlings of 20 treatments with the highest increase in height and diameter were transplanted to the field. Soil was fertilized and limestone was spread; seedlings were distributed into randomized blocks, with six replications. After 12 months, the plants were removed to determine ash, organic carbon, C/N relation contents. The ashes were submitted to digestion to determine nutrient concentrations. Fertilization influenced the levels of ash and organic carbon and C/N relation in S. amazonicum. Results indicate that the species has a potential for energy production.

  17. Evaluation of hard fossil fuel

    International Nuclear Information System (INIS)

    Zivkovic, S.; Nuic, J.

    1999-01-01

    Because of its inexhaustible supplies hard fossil fuel will represent the pillar of the power systems of the 21st century. Only high-calorie fossil fuels have the market value and participate in the world trade. Low-calorie fossil fuels ((brown coal and lignite) are fuels spent on the spot and their value is indirectly expressed through manufactured kWh. For the purpose of determining the real value of a tonne of low-calorie coal, the criteria that help in establishing the value of a tonne of hard coal have to be corrected and thus evaluated and assessed at the market. (author)

  18. Bonding Characteristics of Macrosynthetic Fiber in Latex-Modified Fiber-Reinforced Cement Composites as a Function of Carbon Nanotube Content

    Directory of Open Access Journals (Sweden)

    Ji-Hong Jean

    2016-01-01

    Full Text Available The effect of carbon nanotube content (0, 0.5, 1.0, 1.5, and 2.0% of the cement weight on the bonding properties of macrosynthetic fiber in latex-modified hybrid fiber cement-based composites (LMHFRCCs was evaluated. The slump value, compressive strength, and bonding strength were measured for each LMHFRCC. As the carbon nanotube content increased to 1.5%, the bonding properties of the macrosynthetic fiber improved. However, the bonding performance deteriorated at a carbon nanotube content of 2.0%. A decrease in the fluidity of the mix negatively affected the dispersion of the nanotubes in the LMHFRCCs. The addition of carbon nanotubes also affected the relative bonding strength independently of the improvement in compressive strength. Microscopic analysis of the macrosynthetic fiber surfaces was used to understand changes in the bonding behavior.

  19. The effect of soll water conditions on carbon isotope discrimination and minerals contents in spring-planted wheat

    International Nuclear Information System (INIS)

    Zhu Lin; Liang Zongsuo; Xu Xing; Li Shuhua

    2008-01-01

    Carbon isotope discrimination (triangle open 13 C) has been proposed as indirect selection criterion for transpiration efficiency and grain yield in wheat. However, because of high cost for triangle open 13 C analysis, attempts have been made to identify alternative screening criteria. Ash content (m a ) has been proposed as an alternative criterion for triangle open 13 C in wheat and barley. A pot experiment with three water treatments (45% ± 5% FC, 55% ± 5% FC and 75% ± 5%FC) was conducted and flag leaf triangle open 13 C (triangle openL a ), contents of ash, potassium (K), magnesium (Mg) and calcium (Ca) were measured to study the relationships between triangle open, mineral composition in spring planted bread wheat (Triticum aestivum L.). In the light of the results obtained in this research, the traits measured showed significant differences among the three water treatments. There were variations in triangle openL a between the genotypes derived from contrasting environments. The improved varieties or advanced lines bred in irrigated areas displayed higher triangle open 13 C values, while the improved and local varieties bred in rain-fed areas exhibited lower triangle open 13 C values Significant positive correlations were found between triangle open 13 C and m a in seedlings and second fully developed leaves at elongation stage and in flag leaves at anthesis stage in severe drought treatment (T 1 ) (r=0.790, P 13 C was negatively associated with potassium (K) content in flag leaves in T 2 (r=0.813, P 2 and T 3 (r=0.725, P 13 C and calcium (Ca) content in flag leaves in T 3 (r=0.708, P a is a possible alternative criterion of triangle open 13 C in vegetative organs especially in stressed environments. K, Mg and Ca contents in flag leaf under moderate water stress or feasible water conditions might be new predictive criteria of triangle openL a . (authors)

  20. Effect of sulfur content in a sulfur-activated carbon composite on the electrochemical properties of a lithium/sulfur battery

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin-Woo; Kim, Changhyeon; Ryu, Ho-Suk; Cho, Gyu-Bong; Cho, Kwon-Koo; Kim, Ki-Won [School of Materials Science and Engineering, Gyeongsang National University, Jinju (Korea, Republic of); Ahn, Jou-Hyeon [Department of Chemical & Biological Engineering, Gyeongsang National University, Jinju (Korea, Republic of); Wang, Guoxiu [School of Chemistry and Forensic Science, University of Technology Sydney, Sydney, NSW 2007 (Australia); Ahn, Jae-Pyeung [Advanced Analysis Center, Research Planning & Coordination Division, KIST, Seoul (Korea, Republic of); Ahn, Hyo-Jun, E-mail: ahj@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, Jinju (Korea, Republic of)

    2015-09-15

    Highlights: • The content of sulfur in activated carbon was controlled by solution process. • The sulfur electrode with low sulfur content shows the best performance. • The Li/S battery has capacity of 1360 mAh/g at 1 C and 702 mAh/g at 10 C. - Abstract: The content of sulfur in sulfur/activated carbon composite is controlled from 32.37 wt.% to 55.33 wt.% by a one-step solution-based process. When the sulfur content is limited to 41.21 wt.%, it can be loaded into the pores of an activated carbon matrix in a highly dispersed state. On the contrary, when the sulfur content is 55.33 wt.%, crystalline sulfur can be detected on the surface of the activated carbon matrix. The best electrochemical performance can be obtained for a sulfur electrode with the lowest sulfur content. The sulfur/activated carbon composite with 32.37 wt.% sulfur afforded the highest first discharge capacity of 1360 mAh g{sup −1} at 1 C rate and a large reversible capacity of 702 mAh g{sup −1} at 10 C (16.75 A/g)

  1. Carbon, chromium and molybdenum contents; Teores de carbono, cromo e molibdenio

    Energy Technology Data Exchange (ETDEWEB)

    Sinatora, A; Goldenstein, H; Mei, P R; Albertin, E; Fuoco, R; Mariotto, C L

    1993-12-31

    This work describes solidification experiments on white cast iron, with 15 and 20% of chromium, 2.3, 3.0 and 3.6 % of carbon and 0.0, 1.5 and 2.5 % of molybdenum in test de samples with 30 mm diameter. Measurements were performed on the austenite and eutectic formation arrests, the number of the eutectic carbide particles relative to the total and the eutectic volumes, and the volume fraction of the primary austenite 9 figs., 3 tabs.

  2. Carbon, chromium and molybdenum contents; Teores de carbono, cromo e molibdenio

    Energy Technology Data Exchange (ETDEWEB)

    Sinatora, A; Goldenstein, H.; Mei, P.R.; Albertin, E.; Fuoco, R.; Mariotto, C.L

    1992-12-31

    This work describes solidification experiments on white cast iron, with 15 and 20% of chromium, 2.3, 3.0 and 3.6 % of carbon and 0.0, 1.5 and 2.5 % of molybdenum in test de samples with 30 mm diameter. Measurements were performed on the austenite and eutectic formation arrests, the number of the eutectic carbide particles relative to the total and the eutectic volumes, and the volume fraction of the primary austenite 9 figs., 3 tabs.

  3. Sedimentary facies analysis of a high-frequency, small-scale, peritidal carbonate sequence in the Lower Jurassic of the Tripolis carbonate unit (central western Crete, Greece: Long-lasting emergence and fossil laminar dolocretes horizons

    Directory of Open Access Journals (Sweden)

    Fotini A. Pomoni

    2016-07-01

    Full Text Available The study examines a Lower Jurassic (late Liassic cyclic lagoonal–peritidal stratigraphic unit outcropping in central western Crete (Tripolis unit, which corresponds to the eastern (internal part of the mainland Gavrovo-Tripolis platform, the most significant external platform of the Hellenides. The studied Tripolis carbonate sequence consists of meter-scale, shallowing-upward successions of restricted inner-carbonate platform facies, including cyclically repeated subtidal, intertidal and supratidal facies, that are separated by erosion surfaces (elementary cycles. Each cycle starts with relatively open-marine facies, which are overlain by shallower, more restricted facies (tidal flat progradation. The lithofacies association includes dolomitic intraclastic–peloidal–bioclastic wackestones–packstones/floatstones and grainstones/rudstones dominated by a restricted shallow-marine fauna (bivalves, gastropods, ostracods and seldom benthic foraminifers, representing a shallow subtidal to intertidal, moderately high-energy environment within an inner-platform setting (peritidal environment to restricted lagoon. This lithofacies association has been intermittently subaerially exposed and has undergone diagenetic processes in an inter- or supratidal environment, exhibiting features of vadose diagenesis and pedogenesis due to long-lasting exposure along certain horizons. The peritidal facies are capped by dolocretes controlled by root-activities (laminar dolocretes, peloidal–pisoid dolocretes and massive dolocretes, marking the end of each depositional cycle, and, thus, distinguishing the successive episodes of a prolonged subaerial exposure period and birth of paleosol horizons. Dolocretes consist a diagenetic facies, characterized by several vadose and pedogenic fabrics, including fenestral cavities with geopetal structures, “flower spar” to blocky sparry cement in primary pores, micritic coatings, crudely pelleted walls, alveolar

  4. Stable isotope compositions of organic carbon and contents of organic carbon and nitrogen of lacustrine sediments from sub-arid northern Tanzania

    International Nuclear Information System (INIS)

    Muzuka, A.N.N.

    2006-01-01

    The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid northern Tanzania during the late Pleistocene-Holocene period. Accelerate mass spectrometer (AMS) 14 C ages on total OM for sediments collected from the Ngorongoro Crater Lake indicate that the sedimentation rate is approximately 17 cm/ka. The δ 13 C values from the 20 cm long core (short core) show a downcore increase, whereas that of 500 cm long core (long core), show two peaks enriched in 13 C and three peaks depleted in 13 C. A general downcore increase in the δ 13 C values for the short core suggests changes in the relative proportion of C 3 and C 4 fraction increasing downcore. Similarly, low and high peaks in the long core suggest changes in the relative proportion of C 3 and C 4 with low values having high proportion of C 3 type of material, probably indicating changes in precipitation and lake levels in the area. Deposition of OM depleted in 13 C took place during periods of high precipitation and high lake levels. Although high content of OC and nitrogen in some core sections are associated with elevated C/N ratio values, diagenetic alteration of isotope signature is unlikely to have caused OC and isotope enrichment in sections having high contents of OC and nitrogen. The OC isotope record from Lake Ndutu shows a general downcore decrease in δ 13 C values and contents of OC and nitrogen. (author)

  5. Biogenic carbon in combustible waste: waste composition, variability and measurement uncertainty.

    Science.gov (United States)

    Larsen, Anna W; Fuglsang, Karsten; Pedersen, Niels H; Fellner, Johann; Rechberger, Helmut; Astrup, Thomas

    2013-10-01

    Obtaining accurate data for the contents of biogenic and fossil carbon in thermally-treated waste is essential for determination of the environmental profile of waste technologies. Relations between the variability of waste chemistry and the biogenic and fossil carbon emissions are not well described in the literature. This study addressed the variability of biogenic and fossil carbon in combustible waste received at a municipal solid waste incinerator. Two approaches were compared: (1) radiocarbon dating ((14)C analysis) of carbon dioxide sampled from the flue gas, and (2) mass and energy balance calculations using the balance method. The ability of the two approaches to accurately describe short-term day-to-day variations in carbon emissions, and to which extent these short-term variations could be explained by controlled changes in waste input composition, was evaluated. Finally, the measurement uncertainties related to the two approaches were determined. Two flue gas sampling campaigns at a full-scale waste incinerator were included: one during normal operation and one with controlled waste input. Estimation of carbon contents in the main waste types received was included. Both the (14)C method and the balance method represented promising methods able to provide good quality data for the ratio between biogenic and fossil carbon in waste. The relative uncertainty in the individual experiments was 7-10% (95% confidence interval) for the (14)C method and slightly lower for the balance method.

  6. Recent developments in biodesulfurization of fossil fuels.

    Science.gov (United States)

    Xu, Ping; Feng, Jinhui; Yu, Bo; Li, Fuli; Ma, Cuiqing

    2009-01-01

    The emission of sulfur oxides can have adverse effects on the environment. Biodesulfurization of fossil fuels is attracting more and more attention because such a bioprocess is environmentally friendly. Some techniques of desulfurization have been used or studied to meet the stricter limitation on sulfur content in China. Recent advances have demonstrated the mechanism and developments for biodesulfurization of gasoline, diesel and crude oils by free cells or immobilized cells. Genetic technology was also used to improve sulfur removal efficiencies. In this review, we summarize recent progress mainly in China on petroleum biodesulfurization.

  7. Status of fossil fuel reserves

    International Nuclear Information System (INIS)

    Laherrere, J.

    2005-01-01

    Reserves represent the sum of past and future productions up to the end of production. In most countries the reserve data of fields are confidential. Therefore, fossil fuel reserves are badly known because the published data are more political than technical and many countries make a confusion between resources and reserves. The cumulated production of fossil fuels represents only between a third and a fifth of the ultimate reserves. The production peak will take place between 2020 and 2050. In the ultimate reserves, which extrapolate the past, the fossil fuels represent three thirds of the overall energy. This document analyses the uncertainties linked with fossil fuel reserves: reliability of published data, modeling of future production, comparison with other energy sources, energy consumption forecasts, reserves/production ratio, exploitation of non-conventional hydrocarbons (tar sands, extra-heavy oils, bituminous shales, coal gas, gas shales, methane in overpressure aquifers, methane hydrates), technology impacts, prices impact, and reserves growth. (J.S.)

  8. The future of oil: unconventional fossil fuels.

    Science.gov (United States)

    Chew, Kenneth J

    2014-01-13

    Unconventional fossil hydrocarbons fall into two categories: resource plays and conversion-sourced hydrocarbons. Resource plays involve the production of accumulations of solid, liquid or gaseous hydro-carbons that have been generated over geological time from organic matter in source rocks. The character of these hydrocarbons may have been modified subsequently, especially in the case of solids and extra-heavy liquids. These unconventional hydrocarbons therefore comprise accumulations of hydrocarbons that are trapped in an unconventional manner and/or whose economic exploitation requires complex and technically advanced production methods. This review focuses primarily on unconventional liquid hydro-carbons. The future potential of unconventional gas, especially shale gas, is also discussed, as it is revolutionizing the energy outlook in North America and elsewhere.

  9. EFFECT OF CROP ROTATION AND LONG TERM FERTILIZATION ON THE CARBON AND GLOMALIN CONTENT IN THE SOIL

    Directory of Open Access Journals (Sweden)

    Piotr WOJEWÓDZKI

    2012-12-01

    Full Text Available The research was performed on the basis of soil samples taken from a multi-year long fertilization experiment carried out in Skierniewice. The source of samples was soil under potato and rye cultivated in monoculture and in the 5-fields rotation system. The following combinations of fertilization were concerned: Ca, NPK and CaNPK (doses since 1976: 1.6 t·ha-1 CaO every 4 years in monoculture and 2 t·ha-1 CaO every 5 years in crop rotation, 90 kg·ha-1 N, 26 kg·ha-1 P, 91 kg·ha-1 K. Laboratory analyzes involved determination of total organic carbon (TOC and glomalin operationally described as a total glomalin related soil protein (TGRSP. It was found that regardless of cultivated plants and the method of fertilization, only cultivation system such as rotation and monoculture significantly influenced the content of TGRSP. TOC was significantly influenced by interaction between species of cultivated plant and the system of cultivation. The analyzed factors within the method of cultivation (monoculture and crop rotation did not influence significantly the TGRSP content while cultivated plant species, in monoculture, significantly influenced on TOC content. There was also noted positive correlation (r = 0.72 between TGRSP and TOC.

  10. Surface chemistry control for selective fossil resin flotation

    Science.gov (United States)

    Miller, J.D.; Yi, Y.; Yu, Q.

    1994-06-07

    A froth flotation method is disclosed for separating fine particles of fossil resin by use of frothing reagents which include an aliphatic organic compound having a polar group and containing not more than four carbon atoms. Butanol is an effective frothing reagent in this method. 12 figs.

  11. The energy challenge of a post-fossil world: Seasonal energy storage

    International Nuclear Information System (INIS)

    Forsberg, C.

    2009-01-01

    Fossil fuels are an energy source and an energy storage system. The demand for electricity and heat varies daily, weekly, and seasonally with seasonal variations often varying by a factor of two or more. The variable demand is met by fossil fuels because 1) fossil fuels are inexpensive to store in coal piles, oil tanks, and underground natural gas storage facilities and 2) the capital cost of the equipment to burn fossil fuels and convert the energy to heat or electricity is small relative to the cost of the fossil fuels. Concerns about climate change may limit the conventional use of fossil fuels. The alternative low-carbon energy production systems (nuclear, fossil fuels with carbon dioxide sequestration, wind, and solar) are capital-intensive energy sources with low operating costs. To obtain favorable economics these technologies must operate at full capacity; but, their output does not match energy demand. We have energy alternatives to fossil fuels but no replacements for the energy storage capabilities or fossil fuels. Proposed strategies and technologies to address the grand storage challenge (including seasonal storage of electricity) are described. The options suggest a nuclear-renewable future to address seasonal energy storage needs in a low-carbon world.

  12. Short-term contributions of cover crop surface residue return to soil carbon and nitrogen contents in temperate Australia.

    Science.gov (United States)

    Zhou, Xiaoqi; Wu, Hanwen; Li, Guangdi; Chen, Chengrong

    2016-11-01

    Cover crop species are usually grown to control weeds. After cover crop harvest, crop residue is applied on the ground to improve soil fertility and crop productivity. Little information is available about quantifying the contributions of cover crop application to soil total carbon (C) and nitrogen (N) contents in temperate Australia. Here, we selected eight cover crop treatments, including two legume crops (vetch and field pea), four non-legume crops (rye, wheat, Saia oat, and Indian mustard), a mixture of rye and vetch, and a nil-crop control in temperate Australia to calculate the contributions of cover crops (crop growth + residue decomposition) to soil C and N contents. Cover crops were sown in May 2009 (autumn). After harvest, the crop residue was placed on the soil surface in October 2009. Soil and crop samples were collected in October 2009 after harvest and in May 2010 after 8 months of residue decomposition. We examined cover crop residue biomass, soil and crop total C and N contents, and soil microbial biomass C and N contents. The results showed that cover crop application increased the mean soil total C by 187-253 kg ha -1 and the mean soil total N by 16.3-19.1 kg ha -1 relative to the nil-crop treatment, except for the mixture treatment, which had similar total C and N contents to the nil-crop control. Cover crop application increased the mean soil microbial biomass C by 15.5-20.9 kg ha -1 and the mean soil microbial biomass N by 4.5-10.2 kg ha -1 . We calculated the apparent percentage of soil total C derived from cover crop residue C losses and found that legume crops accounted for 10.6-13.9 %, whereas non-legume crops accounted for 16.4-18.4 % except for the mixture treatment (0.2 %). Overall, short-term cover crop application increased soil total C and N contents and microbial biomass C and N contents, which might help reduce N fertilizer use and improve sustainable agricultural development.

  13. Right-handed fossil humans.

    Science.gov (United States)

    Lozano, Marina; Estalrrich, Almudena; Bondioli, Luca; Fiore, Ivana; Bermúdez de Castro, José-Maria; Arsuaga, Juan Luis; Carbonell, Eudald; Rosas, Antonio; Frayer, David W

    2017-11-01

    Fossil hominids often processed material held between their upper and lower teeth. Pulling with one hand and cutting with the other, they occasionally left impact cut marks on the lip (labial) surface of their incisors and canines. From these actions, it possible to determine the dominant hand used. The frequency of these oblique striations in an array of fossil hominins documents the typically modern pattern of 9 right- to 1 left-hander. This ratio among living Homo sapiens differs from that among chimpanzees and bonobos and more distant primate relatives. Together, all studies of living people affirm that dominant right-handedness is a uniquely modern human trait. The same pattern extends deep into our past. Thus far, the majority of inferred right-handed fossils come from Europe, but a single maxilla from a Homo habilis, OH-65, shows a predominance of right oblique scratches, thus extending right-handedness into the early Pleistocene of Africa. Other studies show right-handedness in more recent African, Chinese, and Levantine fossils, but the sample compiled for non-European fossil specimens remains small. Fossil specimens from Sima del los Huesos and a variety of European Neandertal sites are predominately right-handed. We argue the 9:1 handedness ratio in Neandertals and the earlier inhabitants of Europe constitutes evidence for a modern pattern of handedness well before the appearance of modern Homo sapiens. © 2017 Wiley Periodicals, Inc.

  14. Dating of two paleolithic human fossils from Romania by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Olariu, Agata; Alexandrescu, Emilian; Skog, Goeran; Hellborg, Ragnar; Stenstroem, Kristina; Faarinen, Mikko; Persson, Per

    2003-01-01

    In this study, we have dated two human fossil remains from Romania by the method of radiocarbon using the technique of the accelerator mass spectrometry at the Pelletron system of Lund University, Sweden. Two fossil remains appear to be the most ancient human remains ever dated in our country: 1. A skull, a scapula and a tibia found in Baia de Fier in the Women's Cave, in Gorj county in the province Oltenia, by Constantin Nicolaescu-Plopsor in 1952; 2. A skull found in Cioclovina cave, near commune Bosorod, Hunedoara county in Transilvania by a worker at the exploitation of phosphate deposits in the year 1941. The skull was examined by Francisc Rainer, anthropologist, and Ioan Simionescu, geologist, who published a study. The lack of stratigraphic observations made very difficult the cultural and chronological assignments of this skull. These authors advanced the hypothesis that the skull belongs to the man of the type Homo sapiens fossilis. At the same time, a number of archaeologists believed that the skull might belong to a modern man, but there have been doubts about this matter. Under this circumstance, dating of the two skulls by physical analysis methods appears to be decisive. Samples of bone were taken from the scapula and tibia from Woman's cave, Baia de Fier and from the skull from Cioclovina cave. The content of Carbon 14 have been determined in the two samples by using the technique of accelerator mass spectrometry (AMS), performed at the AMS system of Lund University, in Sweden. Usually, the collagen amount sufficient for AMS measurements can be extracted from bone fragments with masses of 1 g or more (what provides 5 to 10% of the original collagen content). But, in the situation of the present studied fossil remains, because of the small quantity of bone samples and because the bones were very old, the determination of radiocarbon in the skulls was not so simple. For the preparation of the bone samples, we have essentially applied the Longin method

  15. Oxidation of an activated carbon commercial and characterization of the content of superficial acid groups

    International Nuclear Information System (INIS)

    Cortes, Juan Carlos; Giraldo Liliana; Garcia, Andres A; Garcia, Cesar; Moreno, Juan C

    2008-01-01

    The changes of the surface acid groups of an activated commercial carbon after placing it under oxidation treatment with nitric acid are studied. The time used was in the range 1.5 and 9 hours, the concentrations range was from 4 to 7 molL -1 . The study included the determination of immersion enthalpy. Boehm's type titrations, FTIR, and pH at the point of zero charge, pH p zc. It was found that total acid groups are in a range from 0.207 mmolg -1 to 1.247 mmolg -1 , and that they are proportional to the immersion enthalpy in NaOH that are between 40 and 54Jg -1 . The pH p zc decreases with the oxidation treatment and have values between 8.3 and 4.3

  16. Fossilization History of Fossil Resin from Jambi Province (Sumatra, Indonesia Based on Physico-Chemical Studies

    Directory of Open Access Journals (Sweden)

    Beata Naglik

    2018-03-01

    Full Text Available A unique specimen of fossil resin originating from the Dipterocarpaceae tree family found in Miocene brown coal deposits in Jambi Province (Sumatra, Indonesia was investigated via microscopic observations, microhardness testing and infrared and Raman spectroscopic methods. Its form is rare in nature, being an aggregate of three varieties of resin differing in colour, transparency and internal structure. This suggests the formation of the resins at different stages. Further alteration processes, including fossilization and maturation of the resin in a swamp environment resulted in stepwise aromatization of the cyclohexane ring in steroids and cross-linking through formation of ester bonds as well as carbon–carbon bonds between steroid molecules. The various environmental and geological conditions affecting the formation processes of the resins were recorded in their physico-chemical properties. Additionally, heating conditions accelerated by volcanism were proposed as a factor determining the maturation grade of the resin.

  17. H.R. 804: A Bill to amend the Internal Revenue Code of 1986 to reduce emissions of carbon dioxide by imposing a tax on certain fuels based on their carbon content. Introduced in the House of Representatives, One Hundred Third Congress, First Session, February 3, 1993

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    H.R. 804 proposes the imposition of a carbon tax on primary fossil fuels. In general, Chapter 38 of the Internal Revenue Code of 1986 is to be amended by adding at the end thereof the following new subchapter: open-quotes Subchapter E--Carbon Tax on Primary Fossil Fuels.close quotes Section 4691 will be concerned with the tax on coal; Section 4692 with the tax on petroleum; Section 4693 with the tax on natural gas; and Section 4694 will discuss inflation adjustments

  18. Carbon exchange in biological soil crust communities under differential temperatures and soil water contents: implications for global change

    Science.gov (United States)

    Grote, Edmund E.; Belnap, Jayne; Housman, David C.; Sparks, Jed P.

    2010-01-01

    Biological soil crusts (biocrusts) are an integral part of the soil system in arid regions worldwide, stabilizing soil surfaces, aiding vascular plant establishment, and are significant sources of ecosystem nitrogen and carbon. Hydration and temperature primarily control ecosystem CO2 flux in these systems. Using constructed mesocosms for incubations under controlled laboratory conditions, we examined the effect of temperature (5-35 1C) and water content (WC, 20-100%) on CO2 exchange in light cyanobacterially dominated) and dark cyanobacteria/lichen and moss dominated) biocrusts of the cool Colorado Plateau Desert in Utah and the hot Chihuahuan Desert in New Mexico. In light crusts from both Utah and New Mexico, net photosynthesis was highest at temperatures 430 1C. Net photosynthesis in light crusts from Utah was relatively insensitive to changes in soil moisture. In contrast, light crusts from New Mexico tended to exhibit higher rates of net photosynthesis at higher soil moisture. Dark crusts originating from both sites exhibited the greatest net photosynthesis at intermediate soil water content (40-60%). Declines in net photosynthesis were observed in dark crusts with crusts from Utah showing declines at temperatures 425 1C and those originating from New Mexico showing declines at temperatures 435 1C. Maximum net photosynthesis in all crust types from all locations were strongly influenced by offsets in the optimal temperature and water content for gross photosynthesis compared with dark respiration. Gross photosynthesis tended to be maximized at some intermediate value of temperature and water content and dark respiration tended to increase linearly. The results of this study suggest biocrusts are capable of CO2 exchange under a wide range of conditions. However, significant changes in the magnitude of this exchange should be expected for the temperature and precipitation changes suggested by current climate models.

  19. Respiratory Effects of Inhaled Single-Walled Carbon Nanotubes: The Role of Particle Morphology and Iron Content

    Science.gov (United States)

    Madl, Amy Kathleen

    Nanotechnology provides promise for significant advancements in a number of different fields including imaging, electronics, and therapeutics. With worldwide production of carbon nanotubes (CNTs) exceeding over 500 metric tons annually and industry growth expecting to double over the next 5 yr, there are concerns our understanding of the hazards of these nanomaterials may not be keeping pace with market demand. The physicochemical properties of CNTs may delineate the key features that determine either toxicity or biocompatibility and assist in evaluating the potential health risks posed in industrial and consumer product settings. We hypothesized that the iron content and morphology of inhaled single-walled carbon nanotubes (SWCNTs) influences the extent of cellular injury and alters homeostasis in the lung. To address this hypothesis, (1) an aerosol system was developed to deliver carbon-based nanomaterials in a manner of exposure that is physiologically and environmentally relevant (e.g., inhalation), (2) acute (1 d) and subacute (10 d) nose-only inhalation studies to a well-characterized aerosol of iron-containing (FeSWCNT) versus cleaned (iron removed, cSWCNTs) SWCNTs were conducted to evaluate the time-course patterns of possible injury through measurement of markers of cytotoxicity, inflammation, and cellular remodeling/homeostasis, and (3) the effects of SWCNTs were compared to other well-studied materials (e.g. non-fibrous, low-iron content ultrafine carbon black and fibrous, high-iron content, highly persistent, durable and potent carcinogen crocidolite) to offer insights into the relative toxicity of these nanomaterials as well as the possible mechanisms by which the effects occur. Rats (SD) were exposed to either aerosolized SWCNTs (raw FeSWCNT or purified cSWCNT), carbon black (CB), crocidolite, or fresh air via nose-only inhalation. Markers of inflammation and cytotoxicity in lung lavage, mucin in different airway generations, and collagen in the

  20. The soil organic carbon content of anthropogenically altered organic soils effects the dissolved organic matter quality, but not the dissolved organic carbon concentrations

    Science.gov (United States)

    Frank, Stefan; Tiemeyer, Bärbel; Bechtold, Michel; Lücke, Andreas; Bol, Roland

    2016-04-01

    Dissolved organic carbon (DOC) is an important link between terrestrial and aquatic ecosystems. This is especially true for peatlands which usually show high concentrations of DOC due to the high stocks of soil organic carbon (SOC). Most previous studies found that DOC concentrations in the soil solution depend on the SOC content. Thus, one would expect low DOC concentrations in peatlands which have anthropogenically been altered by mixing with sand. Here, we want to show the effect of SOC and groundwater level on the quantity and quality of the dissolved organic matter (DOM). Three sampling sites were installed in a strongly disturbed bog. Two sites differ in SOC (Site A: 48%, Site B: 9%) but show the same mean annual groundwater level of 15 and 18 cm below ground, respectively. The SOC content of site C (11%) is similar to Site B, but the groundwater level is much lower (-31 cm) than at the other two sites. All sites have a similar depth of the organic horizon (30 cm) and the same land-use (low-intensity sheep grazing). Over two years, the soil solution was sampled bi-weekly in three depths (15, 30 and 60 cm) and three replicates. All samples were analyzed for DOC and selected samples for dissolved organic nitrogen (DON) and delta-13C and delta-15N. Despite differences in SOC and groundwater level, DOC concentrations did not differ significantly (A: 192 ± 62 mg/L, B: 163 ± 55 mg/L and C: 191 ± 97 mg/L). At all sites, DOC concentrations exceed typical values for peatlands by far and emphasize the relevance even of strongly disturbed organic soils for DOC losses. Individual DOC concentrations were controlled by the temperature and the groundwater level over the preceding weeks. Differences in DOM quality were clearer. At site B with a low SOC content, the DOC:DON ratio of the soil solution equals the soil's C:N ratio, but the DOC:DON ratio is much higher than the C:N ratio at site A. In all cases, the DOC:DON ratio strongly correlates with delta-13C. There is no

  1. Inferring brown carbon content from UV aerosol absorption measurements during biomass burning season

    Science.gov (United States)

    Mok, J.; Krotkov, N. A.; Arola, A. T.; Torres, O.; Jethva, H. T.; Andrade, M.; Labow, G. J.; Eck, T. F.; Li, Z.; Dickerson, R. R.; Stenchikov, G. L.; Osipov, S.

    2015-12-01

    Measuring spectral dependence of light absorption by colored organic or "brown" carbon (BrC) is important, because of its effects on photolysis rates of ozone and surface ultraviolet (UV) radiation. Enhanced UV spectral absorption by BrC can in turn be exploited for simultaneous retrievals of BrC and black carbon (BC) column amounts in field campaigns. We present an innovative ground-based retrieval of BC and BrC volume fractions and their mass absorption efficiencies during the biomass burning season in Santa Cruz, Bolivia in September-October 2007. Our method combines retrieval of BC volume fraction using AERONET inversion in visible wavelengths with the inversion of total BC+BrC absorption (i.e., column effective imaginary refractive index, kmeas) using Diffuse/Direct irradiance measurements in UV wavelengths. First, we retrieve BrC volume fraction by fitting kmeas at 368nm using Maxwell-Garnett (MG) mixing rules assuming: (1) flat spectral dependence of kBC, (2) known value of kBrC at 368nm from laboratory absorption measurements or smoke chamber experiments, and (3) known BC volume fraction from AERONET inversion. Next, we derive kBrC in short UVB wavelengths by fitting kmeas at 305nm, 311nm, 317nm, 325nm, and 332nm using MG mixing rules and fixed volume fractions of BC and BrC. Our retrievals show larger than expected spectral dependence of kBrC in UVB wavelengths, implying reduced surface UVB irradiance and inhibited photolysis rates of surface ozone destruction. We use a one-dimensional chemical box model to show that the observed strong wavelength dependence of BrC absorption leads to inhibited photolysis of ozone to O(1D), a loss mechanism, while having little impact or even accelerating photolysis of NO2, an ozone production mechanism. Although BC only absorption in biomass burning aerosols is important for climate radiative forcing in the visible wavelengths, additional absorption by BrC is important because of its impact on surface UVB radiation

  2. Uncertainty in projected climate change arising from uncertain fossil-fuel emission factors

    Science.gov (United States)

    Quilcaille, Y.; Gasser, T.; Ciais, P.; Lecocq, F.; Janssens-Maenhout, G.; Mohr, S.

    2018-04-01

    Emission inventories are widely used by the climate community, but their uncertainties are rarely accounted for. In this study, we evaluate the uncertainty in projected climate change induced by uncertainties in fossil-fuel emissions, accounting for non-CO2 species co-emitted with the combustion of fossil-fuels and their use in industrial processes. Using consistent historical reconstructions and three contrasted future projections of fossil-fuel extraction from Mohr et al we calculate CO2 emissions and their uncertainties stemming from estimates of fuel carbon content, net calorific value and oxidation fraction. Our historical reconstructions of fossil-fuel CO2 emissions are consistent with other inventories in terms of average and range. The uncertainties sum up to a ±15% relative uncertainty in cumulative CO2 emissions by 2300. Uncertainties in the emissions of non-CO2 species associated with the use of fossil fuels are estimated using co-emission ratios varying with time. Using these inputs, we use the compact Earth system model OSCAR v2.2 and a Monte Carlo setup, in order to attribute the uncertainty in projected global surface temperature change (ΔT) to three sources of uncertainty, namely on the Earth system’s response, on fossil-fuel CO2 emission and on non-CO2 co-emissions. Under the three future fuel extraction scenarios, we simulate the median ΔT to be 1.9, 2.7 or 4.0 °C in 2300, with an associated 90% confidence interval of about 65%, 52% and 42%. We show that virtually all of the total uncertainty is attributable to the uncertainty in the future Earth system’s response to the anthropogenic perturbation. We conclude that the uncertainty in emission estimates can be neglected for global temperature projections in the face of the large uncertainty in the Earth system response to the forcing of emissions. We show that this result does not hold for all variables of the climate system, such as the atmospheric partial pressure of CO2 and the

  3. Fed-batch cultivation of baker's yeast followed by nitrogen or carbon starvation: effects on fermentative capacity and content of trehalose and glycogen

    DEFF Research Database (Denmark)

    Jørgensen, Henning; Olsson, Lisbeth; Rønnow, B.

    2002-01-01

    , trehalose and glycogen. Nitrogen starvation triggered the accumulation of trehalose and glycogen. After 8 h of starvation, the content of trehalose and glycogen was increased 4-fold and 2-fold, respectively. Carbon starvation resulted in a partial conversion of glycogen into trehalose. The trehalose content...... increased from 45 to 64 mg (g dry-weight)(-1), whereas the glycogen content in the same period was reduced from 55 to 5 mg (g dry-weight)(-1). Glycogen was consumed faster than trehalose during storage of the starved yeast for 1 month. Nitrogen starvation resulted in a decrease in the protein content...

  4. Uranium concentrations in fossils measured by SIMS

    International Nuclear Information System (INIS)

    Uyeda, Chiaki; Okano, Jun

    1988-01-01

    Semiquantitative analyses of uranium in fossil bones and teeth were carried out by SIMS. The results show a tendency that uranium concentrations in the fossils increase with the ages of the fossils. It is noticed that fossil bones and teeth having uranium concentration of more than several hundred ppm are not rare. (author)

  5. Uranium-series dating of fossil bones from alpine caves

    International Nuclear Information System (INIS)

    Leitner-Wild, E.; Steffan, I.

    1993-01-01

    During the course of an investigation of fossil cave bear populations the uranium-series method for absolute age determination has been applied to bone material. The applicability of the method to bone samples from alpine caves is demonstrated by the concordance of U/Th and U/Pa ages and cross-checks with the radiocarbon method. Stratigraphic agreement between bone ages and carbonate speleothem ages also indicates the potential of the uranium-series method as a suitable tool for the age determination of fossil bones from alpine cave environments. (Author)

  6. Chromium Extraction via Chemical Processing of Fe-Cr Alloys Fine Powder with High Carbon Content

    Science.gov (United States)

    Torres, D. M.; Navarro, R. C. S.; Souza, R. F. M.; Brocchi, E. A.

    2017-06-01

    Ferrous alloys are important raw materials for special steel production. In this context, alloys from the Fe-Cr system, with typical Cr weight fraction ranging from 0.45 to 0.95, are prominent, particularly for the stainless steel industry. During the process in which these alloys are obtained, there is considerable production of fine powder, which could be reused after suitable chemical treatment, for example, through coupling pyrometallurgical and hydrometallurgical processes. In the present study, the extraction of chromium from fine powder generated during the production of a Fe-Cr alloy with high C content was investigated. Roasting reactions were performed at 1073 K, 1173 K, and 1273 K (800 °C, 900 °C, and 1000 °C) with 300 pct (w/w) excess NaOH in an oxidizing atmosphere (air), followed by solubilization in deionized water, selective precipitation, and subsequent calcination at 1173 K (900 °C) in order to convert the obtained chromium hydroxide to Cr2O3. The maximum achieved Cr recovery was around 86 pct, suggesting that the proposed chemical route was satisfactory regarding the extraction of the chromium initially present. Moreover, after X-ray diffraction analysis, the final produced oxide has proven to be pure Cr2O3 with a mean crystallite size of 200 nm.

  7. CMS: CO2 Emissions from Fossil Fuels Combustion, ACES Inventory for Northeastern USA

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset provides estimates of annual and hourly carbon dioxide (CO2) emissions from the combustion of fossil fuels (FF) for 13 states across the Northeastern...

  8. Gel spinning of PVA composite fibers with high content of multi-walled carbon nanotubes and graphene oxide hybrids

    International Nuclear Information System (INIS)

    Wei, Yizhe; Lai, Dengpan; Zou, Liming; Ling, Xinlong; Lu, Hongwei; Xu, Yongjing

    2015-01-01

    In this report, poly (vinyl alcohol) (PVA) composite fibers with high content of multi-walled carbon nanotubes and graphene oxide (MWCNTs-GO) hybrids were prepared by gel spinning, and were characterized by TGA, DSC, SEM, XL-2 yarn strength tester and electrical conductivity measurement. The total content of MWCNTs-GO hybrids in the PVA composite fibers, which is up to 25 wt%, was confirmed by TGA analysis. The DSC measurement shows that the melting and crystallization peaks decreased after the addition of nano-fillers. This is due to the reason that the motion of PVA chains is completely confined by strong hydrogen bonding interaction between PVA and nano-fillers. After the addtion of GO, the dispersibility of MWCNTs in composite fibers improved slightly. And the tensile strength and Young's modulus increased by 38% and 67%, respectively. This is caused by the increased hydrogen bonding interaction and synergistic effect through hybridization of MWCNTs and GO. More significantly, the electrical conductivity of PVA/MWCNTs/GO composite fibers enhanced by three orders of magnitude with the addition of GO. (paper)

  9. Sulphur, nitrogen and carbon content of Sphagnum capillifolium and Pseudevernia furfuracea exposed in bags in the Naples urban area

    International Nuclear Information System (INIS)

    Vingiani, S.; Adamo, P.; Giordano, S.

    2004-01-01

    The accumulation ability of the major elements sulphur, nitrogen and carbon by the moss Sphagnum capillifolium (Ehrh.) Hedw. and the lichen Pseudevernia furfuracea (L.) Zopf exposed in bags in Naples urban area,was investigated. Bags were exposed at the beginning of July 1999 and gathered in two subsequent moments: at the end of the dry season (after 10 weeks of exposure) and during the wet season (after 17 weeks of exposure), to include the effects of rainy conditions. Sulphur and N content of the lichen increased all over the exposure period, while the level of C did not change significantly either after 10 or 17 weeks of exposition. For the moss the S accumulation was limited to the dry period of exposure, whereas N and C content decreased with exposure. Results, in contrast with those obtained in a previous study on trace elements bioaccumulation [Adamo et al., Environmental Pollution, (2003) 122, 91-103], suggest that accumulation of gaseous pollutants is strongly influenced by biomonitor vitality and that lichen bags are a more reliable and effective tool for monitoring S, N and C atmospheric depositions in urban areas compared to moss bags, because of greater lichen resistance to dry and stressing conditions of urban environment. - The lichen Pseudevernia furfuracea is more effective than the moss Sphagnum capillifolium as S and N pollutants biomonitor

  10. Influence of carbon content on the copper-telluride phase formation and on the resistive switching behavior of carbon alloyed Cu-Te conductive bridge random access memory cells

    International Nuclear Information System (INIS)

    Devulder, Wouter; De Schutter, Bob; Detavernier, Christophe; Opsomer, Karl; Franquet, Alexis; Meersschaut, Johan; Muller, Robert; Van Elshocht, Sven; Jurczak, Malgorzata; Goux, Ludovic; Belmonte, Attilio

    2014-01-01

    In this paper, we investigate the influence of the carbon content on the Cu-Te phase formation and on the resistive switching behavior in carbon alloyed Cu 0.6 Te 0.4 based conductive bridge random access memory (CBRAM) cells. Carbon alloying of copper-tellurium inhibits the crystallization, while attractive switching behavior is preserved when using the material as Cu-supply layer in CBRAM cells. The phase formation is first investigated in a combinatorial way. With increasing carbon content, an enlargement of the temperature window in which the material stays amorphous was observed. Moreover, if crystalline phases are formed, subsequent phase transformations are inhibited. The electrical switching behavior of memory cells with different carbon contents is then investigated by implementing them in 580 μm diameter dot TiN/Cu 0.6 Te 0.4 -C/Al 2 O 3 /Si memory cells. Reliable switching behavior is observed for carbon contents up to 40 at. %, with a resistive window of more than 2 orders of magnitude, whereas for 50 at. % carbon, a higher current in the off state and only a small resistive window are present after repeated cycling. This degradation can be ascribed to the higher thermal and lower drift contribution to the reset operation due to a lower Cu affinity towards the supply layer, leading cycle-after-cycle to an increasing amount of Cu in the switching layer, which contributes to the current. The thermal diffusion of Cu into Al 2 O 3 under annealing also gives an indication of the Cu affinity of the source layer. Time of flight secondary ion mass spectroscopy was used to investigate this migration depth in Al 2 O 3 before and after annealing, showing a higher Cu, Te, and C migration for high carbon contents

  11. Influence of carbon content on the copper-telluride phase formation and on the resistive switching behavior of carbon alloyed Cu-Te conductive bridge random access memory cells

    Science.gov (United States)

    Devulder, Wouter; Opsomer, Karl; Franquet, Alexis; Meersschaut, Johan; Belmonte, Attilio; Muller, Robert; De Schutter, Bob; Van Elshocht, Sven; Jurczak, Malgorzata; Goux, Ludovic; Detavernier, Christophe

    2014-02-01

    In this paper, we investigate the influence of the carbon content on the Cu-Te phase formation and on the resistive switching behavior in carbon alloyed Cu0.6Te0.4 based conductive bridge random access memory (CBRAM) cells. Carbon alloying of copper-tellurium inhibits the crystallization, while attractive switching behavior is preserved when using the material as Cu-supply layer in CBRAM cells. The phase formation is first investigated in a combinatorial way. With increasing carbon content, an enlargement of the temperature window in which the material stays amorphous was observed. Moreover, if crystalline phases are formed, subsequent phase transformations are inhibited. The electrical switching behavior of memory cells with different carbon contents is then investigated by implementing them in 580 μm diameter dot TiN/Cu0.6Te0.4-C/Al2O3/Si memory cells. Reliable switching behavior is observed for carbon contents up to 40 at. %, with a resistive window of more than 2 orders of magnitude, whereas for 50 at. % carbon, a higher current in the off state and only a small resistive window are present after repeated cycling. This degradation can be ascribed to the higher thermal and lower drift contribution to the reset operation due to a lower Cu affinity towards the supply layer, leading cycle-after-cycle to an increasing amount of Cu in the switching layer, which contributes to the current. The thermal diffusion of Cu into Al2O3 under annealing also gives an indication of the Cu affinity of the source layer. Time of flight secondary ion mass spectroscopy was used to investigate this migration depth in Al2O3 before and after annealing, showing a higher Cu, Te, and C migration for high carbon contents.

  12. Empirical observations offer improved estimates of forest floor carbon content across in the United States

    Science.gov (United States)

    Perry, C. H.; Domke, G. M.; Walters, B. F.; Smith, J. E.; Woodall, C. W.

    2014-12-01

    The Forest Inventory and Analysis (FIA) program of the United States Forest Service reports official estimates of national forest floor carbon (FFC) stocks and stock change to national and international parties, the US Environmental Protection Agency (USEPA) and the United Nations Framework Convention on Climate Change (UNFCCC), respectively. These estimates of national FFC stocks are derived from plot-level predictions of FFC density. We suspect the models used to predict plot-level FFC density are less than ideal for several reasons: (a) they are based upon local studies that may not reflect FFC dynamics at the national scale, (b) they are relatively insensitive to climate change, and (c) they reduce the natural variability of the data leading to misplaced confidence in the estimates. However, FIA has measured forest floor attributes since 2001 on a systematic 1/16th subset of a nation-wide array of inventory plots (7 800 of 125 000 plots). Here we address the efficacy of replacing plot-level model predictions with empirical observations of FFC density while assessing the impact of imputing FFC density values to the full plot network on national stock estimates. First, using an equivalence testing framework, we found model predictions of FFC density to differ significantly from the observations in all regions and forest types; the mean difference across all plots was 21 percent (1.81 Mg·ha-1). Furthermore, the model predictions were biased towards the lower end of extant FFC density observations, underestimating it while greatly truncating the range relative to the observations. Second, the optimal imputation approach (k-Nearest Neighbor, k-NN) resulted in values that were equivalent to observations of FFC density across a range of simulated missingness and maintained the high variability seen in the observations. We used the k-NN approach to impute FFC density values to the 94 percent of FIA inventory plots without soil measurements. Third, using the imputed

  13. Greenhouse gas emissions reduction from fossil fuels: options and prospects

    International Nuclear Information System (INIS)

    McDonald, M.M.

    1999-01-01

    If levels of carbon dioxide in the atmosphere are to be stabilized over the next 50 years, net emissions from the use of fossil fuels have to be reduced. One concept worth exploring is the removal of carbon dioxide from plant flue gases and disposing of it in a manner that sequesters it from the atmosphere. A number of technologies, which are either commercially available or under development, promise to make this concept viable. The question of where to dispose of the carbon dioxide removed is not the limiting factor, given the potential for use in enhanced hydrocarbon production as well as other geological disposal options. In the longer term, fossil fuel use will significantly decline, but these extraction and sequestration technologies can provide the time for the transition to take place in a manner which causes least impact to the economies of the world. (author)

  14. Effect of carbon content on the microstructure and creep properties of a 3rd generation single crystal nickel-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.W.; Liu, T. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, L., E-mail: wangli@imr.ac.cn [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Liu, X.G.; Lou, L.H. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, J. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2015-07-15

    Effect of carbon content on the microstructure and creep properties of a 3rd generation single crystal nickel-base superalloy has been investigated by the scanning electron microscope, X-ray computed tomography and electron probe microanalyzer. With the increase of the carbon content, MC carbides evolve from octahedral to well-developed dendrite, which promotes the formation of microporosity. Moreover, the volume fraction of porosity increases in the experimental alloys after solution heat treatment. As a result, the increase in the size of MC carbides and the porosity has a detrimental effect on the low temperature and high stress creep behavior of the alloys. The specimen crept at 850 °C and 586 MPa with the carbon content of 430 ppm shows the shortest rupture life due to the largest primary creep strain. However, the creep behavior of the alloy at 1120 °C and 140 MPa gets better as the carbon content increases from 88 to 430 ppm. TCP phase is observed near the fracture surfaces of the alloys, which explores as a potential cause for the creep rupture. However, the formation of TCP phase is effectively suppressed for decreasing segregation of the alloying elements, which results in the improvement of the creep life in the alloy with 430 ppm carbon at 1120 °C and 140 MPa.

  15. Identification of remanie fossils using amino acid racemisation

    International Nuclear Information System (INIS)

    Murray-Wallace, C.V.

    1997-01-01

    The reworking of fossils into younger sediments presents a significant problem for dating Quaternary marginal marine strata. Studies that involve isotopic dating of carbonate sediment fractions may be subject to error, owing to the difficulties of quantifying the residence times of skeletal carbonate fragments and fossils in some coastal environments. The random and often episodic nature of reworking also means that the value of residence times (i.e. interval from death of an organism to its final incorporation within a sediment), as expressed in years, may vary spatially and temporally. This problem is particularly marked in the dating of skeletal carbonate sands. Thus, the validity of numeric dates for 'whole-rock' carbonate samples, based on methods such as radiocarbon or uranium-series disequilibrium, has on occasions been difficult to establish. This problem is compounded when a specific component of a carbonate sediment is selected for dating. This paper documents the potential of the application of amino acid racemisation reactions as a method for identifying reworked Quaternary fossils, based on case studies from coastal and continental shelf depositional environments

  16. Bainite transformation of low carbon Mn-Si TRIP-assisted multiphase steels: influence of silicon content on cementite precipitation and austenite retention

    International Nuclear Information System (INIS)

    Jacques, P.; Catlin, T.; Geerlofs, N.; Kop, T.; Zwaag, S. van der; Delannay, F.

    1999-01-01

    Studies dealing with TRIP-assisted multiphase steels have emphasized the crucial role of the bainite transformation of silicon-rich intercritical austenite in the achievement of a good combination of strength and ductility. The present work deals with the bainite transformation in two steels differing in their silicon content. It is shown that both carbon enrichment of residual austenite and cementite precipitation influences the kinetics of the bainite transformation. A minimum silicon content is found to be necessary in order to prevent cementite precipitation from austenite during the formation of bainitic ferrite in such a way as to allow stabilisation of austenite by carbon enrichment. (orig.)

  17. Fatty Acid Content of Indonesian Aquatic Microalgae

    Directory of Open Access Journals (Sweden)

    TRI PRARTONO

    2010-12-01

    Full Text Available High utilization of fossil fuel increases the level of carbon dioxide in the atmosphere and results in global warming phenomenon. These things establish the world's thought to look for the other alternative energy that can reduce the use of fossil fuel even to be replaced by the substitute. Recently, Indonesia has been doing the research of microalgae as a feedstock of an alternative biofuel. Fatty acid content that microalgae have is also high to produce biofuel. The steps used in this research is a 7 days cultivation, harvesting, extraction using hexane, and fatty acid identification using Gas Chromatography of microalgae species. Fatty acid component in some species such as Chlorella sp., Scenedesmus sp., Nannochloropsis sp., and Isochrysis sp. is between 0.21-29.5%; 0.11-25.16%; 0.30-42.32%; 2.06-37.63%, respectively, based on dry weight calculation. The high content of fatty acid in some species of microalgae showed the potential to be the feedstock of producing biofuel in overcoming the limited utilization from petroleum (fossil fuel presently.

  18. Fossil Groups as Cosmological Labs

    Science.gov (United States)

    D'Onghia, Elena

    Optical and X-ray measurements of fossil groups (FGs) suggest that they are old and relaxed systems. If FGs are assembled at higher redshift, there is enough time for intermediate-luminosity galaxies to merge, resulting in the formation of the brightest group galaxy (BGG). We carry out the first, systematic study of a large sample of FGs, the "FOssil Group Origins'' (FOGO) based on an International Time Project at the Roque de los Muchachos Observatory. For ten FOGO FGs we have been awarded time at SUZAKU Telescope to measure the temperature of the hot intragroup gas (IGM). For these systems we plan to evaluate and correlate their X-ray luminosity and X-ray temperature, Lx-Tx, optical luminosity and X-ray temperature, Lopt-Tx, and group velocity dispersion with their X-ray temperature, sigma V-Tx, as compared to the non fossil systems. By combining these observations with state-of-art cosmological hydrodynamical simulations we will open a new window into the study of the IGM and the nature of fossil systems. Our proposed work will be of direct relevance for the understanding and interpretation of data from several NASA science missions. Specifically, the scaling relations obtained from these data combined with our predictions obtained using state-of-the-art hydrodynamical simulation numerical adopting a new hydrodynamical scheme will motivate new proposal on CHANDRA X-ray telescope for fossil groups and clusters. We will additionally create a public Online Planetarium Show. This will be an educational site, containing an interactive program called: "A Voyage to our Universe''. In the show we will provide observed images of fossil groups and similar images and movies obtained from the numerical simulations showing their evolution. The online planetarium show will be a useful reference and an interactive educational tool for both students and the public.

  19. FOSSIL2 energy policy model documentation: FOSSIL2 documentation

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-10-01

    This report discusses the structure, derivations, assumptions, and mathematical formulation of the FOSSIL2 model. Each major facet of the model - supply/demand interactions, industry financing, and production - has been designed to parallel closely the actual cause/effect relationships determining the behavior of the United States energy system. The data base for the FOSSIL2 program is large, as is appropriate for a system dynamics simulation model. When possible, all data were obtained from sources well known to experts in the energy field. Cost and resource estimates are based on DOE data whenever possible. This report presents the FOSSIL2 model at several levels. Volumes II and III of this report list the equations that comprise the FOSSIL2 model, along with variable definitions and a cross-reference list of the model variables. Volume II provides the model equations with each of their variables defined, while Volume III lists the equations, and a one line definition for equations, in a shorter, more readable format.

  20. The global environment effects of fossil and nuclear fuels

    International Nuclear Information System (INIS)

    Kemeny, L.G.

    1981-01-01

    The relative risks and environmental impacts of coal and uranium fueled power plants are dicussed. Fossil-fuel power plants are associated with a build-up of carbon dioxide levels and consequent climatic changes, release of sulphur dioxide and resultant acid rains and radioactive emissions. In comparing the discharges per megawatt year of sulphur dioxide, nitrogen dioxide and radioactive Ra-226 and Ra-225 in fly ash from coal and other fossil plants with Kr-85 and I-131 from nuclear plants, the fossil plants have a much poorer performance. Estimates indicate that nuclear energy can be adopted on a large scale as an alternative to coal without any increase in hazards and with a probability of a substantial reduction

  1. The environmental dilemma of fossil fuels

    International Nuclear Information System (INIS)

    MacCracken, M.C.

    1992-04-01

    The increasing atmospheric concentration of carbon dioxide poses an environmental dilemma for fossil fuel energy generation that, unlike other related emissions, cannot be resolved by control technologies alone. Although fossil fuels presently provide the most cost-effective global energy source, and model projections suggest that their use is initiating climatic changes which, while quite uncertain, may induce significant, counter-balancing impacts to water resources, coastal resources, ecological systems, and possibly agricultural production. The climate model indicate that the warming should have begun, and there is some evidence for this occurring, but at a less rapid and more uneven rate than projected. In addition, different climate models are not yet in agreement in their latitudinal or regional predictions, and it will likely require a decade or more for such agreement to develop as high performance computers become available for addressing this ''grand challenge'' problem. Thus, in addition to the prospect for climatic change, the uncertainties of the changes and associated impacts contribute to the dilemma of dealing with the issue. Further, the problem is pervasive and international scope, with different countries and peoples having differing perspectives of technology, development, and environmental responsibility. Dealing with this issue will thus require creativity, commitment, and flexibility

  2. Mapping within-field variations of soil organic carbon content using UAV multispectral visible near-infrared images

    Science.gov (United States)

    Gilliot, Jean-Marc; Vaudour, Emmanuelle; Michelin, Joël

    2016-04-01

    This study was carried out in the framework of the PROSTOCK-Gessol3 project supported by the French Environment and Energy Management Agency (ADEME), the TOSCA-PLEIADES-CO project of the French Space Agency (CNES) and the SOERE PRO network working on environmental impacts of Organic Waste Products recycling on field crops at long time scale. The organic matter is an important soil fertility parameter and previous studies have shown the potential of spectral information measured in the laboratory or directly in the field using field spectro-radiometer or satellite imagery to predict the soil organic carbon (SOC) content. This work proposes a method for a spatial prediction of bare cultivated topsoil SOC content, from Unmanned Aerial Vehicle (UAV) multispectral imagery. An agricultural plot of 13 ha, located in the western region of Paris France, was analysed in April 2013, shortly before sowing while it was still bare soil. Soils comprised haplic luvisols, rendzic cambisols and calcaric or colluvic cambisols. The UAV platform used was a fixed wing provided by Airinov® flying at an altitude of 150m and was equipped with a four channels multispectral visible near-infrared camera MultiSPEC 4C® (550nm, 660nm, 735 nm and 790 nm). Twenty three ground control points (GCP) were sampled within the plot according to soils descriptions. GCP positions were determined with a centimetric DGPS. Different observations and measurements were made synchronously with the drone flight: soil surface description, spectral measurements (with ASD FieldSpec 3® spectroradiometer), roughness measurements by a photogrammetric method. Each of these locations was sampled for both soil standard physico-chemical analysis and soil water content. A Structure From Motion (SFM) processing was done from the UAV imagery to produce a 15 cm resolution multispectral mosaic using the Agisoft Photoscan® software. The SOC content was modelled by partial least squares regression (PLSR) between the

  3. New fossil fuel combustion technologies

    International Nuclear Information System (INIS)

    Minghetti, E.; Palazzi, G.

    1995-01-01

    The aim of the present article is to supply general information concerning fossil fuels that represent, today and for the near future, the main energy source of our Planet. New fossil fuel technologies are in continual development with two principal goals: to decrease environmental impact and increase transformation process efficiency. Examples of this efforts are: 1) gas-steam combined cycles integrated with coal gasification plants, or with pressurized-fluidized-bed combustors; 2) new cycles with humid air or coal direct fired turbine, now under development. In the first part of this article the international and national energy situations and trends are shown. After some brief notes on environmental problems and alternative fuels, such as bio masses and municipal wastes, technological aspects, mainly relevant to increase fossil-fueled power plant performances, are examined in greater depth. Finally the research and technological development activities of ENEA (Italian Agency for New Technologies, Energy and Environment) Engineering Branch, in order to improve fossil fuels energy and environmental use are presented

  4. Progress of fossil fuel science

    Energy Technology Data Exchange (ETDEWEB)

    Demirbas, M.F.

    2007-07-01

    Coal is the most abundant and widely distributed fossil fuel. More than 45% of the world's electricity is generated from coal, and it is the major fuel for generating electricity worldwide. The known coal reserves in the world are enough for more than 215 years of consumption, while the known oil reserves are only about 39 times of the world's consumption and the known natural gas reserves are about 63 times of the world's consumption level in 1998. In recent years, there have been effective scientific investigations on Turkish fossil fuels, which are considerable focused on coal resources. Coal is a major fossil fuel source for Turkey. Turkish coal consumption has been stable over the past decade and currently accounts for about 24% of the country's total energy consumption. Lignite coal has had the biggest share in total fossil fuel production, at 43%, in Turkey. Turkish researchers may investigate ten broad pathways of coal species upgrading, such as desulfurization and oxydesulfurization, pyrolysis and hydropyrolysis, liquefaction and hydroliquefaction, extraction and supercritical fluid extraction, gasification, oxidation, briquetting, flotation, and structure identification.

  5. Fossil Polypodiaceae and their spores

    NARCIS (Netherlands)

    Uffelen, van Gerda A.

    1991-01-01

    In this publication emphasis is laid on the modern definition of the family Polypodiaceae (Filicales), which is based on an extensive study of Recent material and which is much restricted with respect to older circumscriptions of the family as usually applied by palaeobotanists. Fossils of fems

  6. Fossil energy and food security

    International Nuclear Information System (INIS)

    Folke, G.

    2001-01-01

    To fulfil the basic goal of delivering food for the tables of the citizens, modern Western agriculture is extremely dependent on supporting material flows, infrastructure, and fossil energy. According to several observers, fossil fuel production is about to peak, i.e., oil extraction is no longer capable of keeping pace with the increasing demand. This situation may trigger an unprecedented increase in fossil energy prices, which may make the current highly energy dependent food production-distribution system highly vulnerable. The paper starts with a survey of this vulnerability. Also, the supply of phosphorus, a key factor in agriculture, may be at stake under such circumstances. The paper analyses this situation and discusses settlement structures integrated with agriculture that might increase food security by reducing energy demands. In the proposed ideal societal structure, agriculture is integrated with settlements and most of the food needed by the population is produced locally, and the nutrients for food production are recycled from households and animals by means of biological processes demanding considerably less mechanical investment and fossil support energy than the conventional type of agriculture. The vulnerability of this structure would be considerably lower, than that of the current system. (author)

  7. Testing New Proxies for Photosymbiosis in the Fossil Record

    Science.gov (United States)

    Tornabene, C.; Martindale, R. C.; Schaller, M. F.

    2015-12-01

    Photosymbiosis is a mutualistic relationship that many corals have developed with dinoflagellates called zooxanthellae. The dinoflagellates, of the genus Symbiodinium, photosynthesize and provide corals with most of their energy, while in turn coral hosts live in waters where zooxanthellae have optimal exposure to sunlight. Thanks to this relationship, symbiotic corals calcify faster than non-symbiotic corals. Photosymbiosis is therefore considered the evolutionary innovation that allowed corals to become major reef-builders through geological time.This relationship is extremely difficult to study. Zooxanthellae, which are housed in the coral tissue, are not preserved in fossil coral skeletons, thus determining whether corals had symbionts requires a robust proxy. In order to address this critical question, the goal of this research is to test new proxies for ancient photosymbiosis. Currently the project is focused on assessing the nitrogen (δ15N) isotopes of corals' organic matrices, sensu Muscatine et al. (2005), as well as carbon and oxygen (δ13C, δ18O) isotopes of fossil coral skeletons. Samples from Modern, Pleistocene, Oligocene and Triassic coral skeletons were analyzed to test the validity of these proxies. Coral samples comprise both (interpreted) symbiotic and non-symbiotic fossil corals from the Oligocene and Triassic as well as symbiotic fossil corals from the Modern and Pleistocene to corroborate our findings with the results of Muscatine et al. (2005). Samples were tested for diagenesis through petrographic and scanning electron microscope (SEM) analyses to avoid contamination. Additionally, a novel technique that has not yet been applied to the fossil record was tested. The technique aims to recognize dinosterol, a dinoflagellate biomarker, in both modern and fossil coral samples. The premise of this proxy is that symbiotic corals should contain the dinoflagellate biomarker, whereas those lacking symbionts should lack dinosterol. Results from this

  8. Porous carbon-coated ZnO nanoparticles derived from low carbon content formic acid-based Zn(II) metal-organic frameworks towards long cycle lithium-ion anode material

    International Nuclear Information System (INIS)

    Gao, Song; Fan, Ruiqing; Li, Bingjiang; Qiang, Liangsheng; Yang, Yulin

    2016-01-01

    Graphical abstract: The nanocomposites constructed from Zn-based MOFs exhibit low carbon content with super-high rate capability and long cycling life. - Highlights: • Novel ZnO@porous carbon matrix nanocomposites are constructed by pyrolysis of Zn-based MOFs. • The nanocomposites constructed with Zn-based MOFs show low carbon content. • The constructed nanocomposites exhibit high energy density, super-high rate capability and long cycling life. - Abstract: Single-C formic acid-based metal-organic frameworks (MOFs) are used to construct novel ZnO@porous carbon matrix nanocomposites by controlled pyrolysis. In the constructed nanocomposites, the porous carbon matrices act as a confined support to prevent agglomeration of the ZnO nanoparticles and create a rapid electron conductive network. Meanwhile, the well-defined, continuous porous structured MOFs provide a large specific surface area, which increases the contact of electrolyte-electrode and improves the penetration of electrolyte. Especially, the reasonable choice of formic acid-based MOFs construct the low carbon content composite, which contribute to the high energy density and long cycle life. The constructed nanocomposites show stable, ultrahigh rate lithium ion storage properties of 650 mAh g −1 at charge/discharge rate of 1 C even after 200 cycles.

  9. Influence of W content on tribological performance of W-doped diamond-like carbon coatings under dry friction and polyalpha olefin lubrication conditions

    International Nuclear Information System (INIS)

    Fu, Zhi-qiang; Wang, Cheng-biao; Zhang, Wei; Wang, Wei; Yue, Wen; Yu, Xiang; Peng, Zhi-jian; Lin, Song-sheng; Dai, Ming-jiang

    2013-01-01

    Highlights: • W-doped DLC coating with various W contents was fabricated. • Friction and wear of DLC coated sample was studied. • The lubricant additive was T307. • The influence of W content on friction under lubrication was unveiled. • The influence of W content on wear under lubrication was studied. - Abstract: The influence on tungsten content on the structure, mechanical properties and tribological performance of W-doped diamond-like carbon (DLC) coatings was studied by X-ray photoelectron spectroscopy, nano-indentation, scratch test, and ball-on-disk friction test. It was found that with increasing W content, the content of WC and free W in the coatings is increased while the content of sp 3 -C in the coatings is decreased. The effect of W content on the hardness and elastic modulus of the coatings is indistinctive, but there exists the highest critical load of scratch test of above 100 N when W content is 3.08 at.%. With the increase of W content, the friction coefficients of W-doped DLC coatings under dry friction conditions are increased while the friction coefficients of W-doped DLC coatings under polyalpha olefin (PAO) lubrication are decreased. With the increase of W content, the wear rates of the DLC-coated samples under dry friction conditions show a minimum value; under pure PAO lubrication, the influence of W content on the wear rates of the DLC-coated samples is indistinctive when the W content is below 10.73 at.% while the wear rates are increased with increasing W content from 10.73 at.% to 24.09 at.%; when lubricated by PAO + thiophosphoric acid amine (T307) salt, the samples coated with the undoped DLC or the W-doped DLC with high W content exhibit low wear rates

  10. Ranking Renewable and Fossil Fuels on Global Warming Potential Using Respiratory Quotient Concept

    Directory of Open Access Journals (Sweden)

    Kalyan Annamalai

    2018-01-01

    Full Text Available Carbon dioxide (CO2 is one of the greenhouse gases which cause global warming. The amount of fossil fuels consumed to meet the demands in the areas of power and transportation is projected to increase in the upcoming years. Depending on carbon content, each power plant fuel has its own potential to produce carbon dioxide. Similarly, the humans consume food containing carbohydrates (CH, fat, and protein which emit CO2 due to metabolism. The biology literature uses respiratory quotient (RQ, defined as the ratio of CO2 moles exhausted per mole of O2 consumed within the body, to estimate CO2 loading in the blood stream and CO2 in nasal exhaust. Here, we apply that principle in the field of combustion to relate the RQ to CO2 emitted in tons per GJ of energy released when a fuel is combusted. The RQ value of a fuel can be determined either from fuel chemical formulae (from ultimate analyses for most liquid and solid fuels of known composition or from exhaust gas analyses. RQ ranges from 0.5 for methane (CH4 to 1 for pure carbon. Based on the results obtained, the lesser the value of “RQ” of a fuel, the lower its global warming potential. This methodology can be further extended for an “online instantaneous measurement of CO2” in automobiles based on actual fuel use irrespective of fuel composition.

  11. Determination of Ascorbic Acid Content of Some Fruit Juices and Wine by Voltammetry Performed at Pt and Carbon Paste Electrodes

    Directory of Open Access Journals (Sweden)

    Aurel Pisoschi

    2011-02-01

    Full Text Available A method was developed for assessing ascorbic acid concentration in fruit juices and wine by differential pulse voltammetry. The oxidation peak for ascorbic acid occurs at about 530 mV (versus SCE on a Pt strip working electrode and at about 470 mV on a carbon paste working electrode. The influence of the operational parameters like the pulse amplitude and the pulse period on the analytical signal was investigated. The obtained calibration graph shows a linear dependence between the peak height and ascorbic acid concentration within the range 0.31-20 mM with a Pt working electrode, and within the range 0.07-20 mM with a carbon paste working electrode. The equation of the calibration graph was y = 21.839x + 35.726, r2 = 0.9940, when a Pt strip electrode was used (where y represents the value of the current intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM. R.S.D. = 2.09%, n = 10, Cascorbic acid = 2.5 mM. The equation of the calibration graph was y = 3.4429x + 5.7334, r2 = 0.9971, when a carbon paste electrode was used (where y represents the value of intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM. R.S.D. = 2.35%, n = 10, Cascorbic acid = 2.5 mM. The developed method was applied to ascorbic acid assessment in fruit juices and wine. The ascorbic acid content determined ranged between 6.83 mg/100 mL juice for soft drinks (Fanta Madness and 54.74 mg/100 mL for citrus (lemon juices obtained by squeezing fruit. Different ascorbic acid concentrations (from standard solutions were added to the analysed samples, the degree of recovery being comprised between 94.74 and 104.97%. The results of ascorbic acid assessment by differential pulse voltammetry were compared with those obtained by cyclic voltammetry. The results obtained by the two methods were in good agreement.

  12. Determination of water, hydrogen, and carbon content of Korean main farm produces for the calculation of H-3 and C-14 ingestion dose

    International Nuclear Information System (INIS)

    Chung, Yang Geun; Lee, Gab Bock; Kim, Mi Ja; Eum, Hee Moon

    2003-01-01

    Water, hydrogen, and carbon content of grains, leafy vegetable, root vegetable, and fruits in Korea were determined to be used in the calculation of HTO, OBT, C-14 offsite ingestion dose. The individual items and the weighting factors of the 4 groups were based on the results of nationwide dietary intake survey in Korea. Items produced in an island or imported were excluded for the reason that they would not be affected directly by the nuclear power plants in the nation. On the same assumption, cooked and instant foods also were excluded. Items within 95% of the cumulative percentage of intake in each category were selected as the main farm produces, and then each intake percentage was taken as the weighting factor. Water, Hydrogen, and carbon content were determined using the data in Food Composition TABLE of Korea. H and C content were calculated from protein, fat, and carbohydrate content in the TABLE, and multiplied by each weighting factor to make the group-representative value. Grains, lefty and root vegetable, and fruits of Korea had 11.0%, 93.6%, 87.9%, 86.2% of water, 5.6%, 0.4%. 0.7%, 0.9% of hydrogen, and 39.6%, 2.5%, 5.2%, 6.0% of carbon, respectively. This is different from those in the ODCM from AECL data. Over ODCM, water content of grains and vegetable were 0.92-0.98 times ODCM, and fruits 1.03 times ODCM, which would result in the change of HTO ingestion dose as much. Hydrogen content of grains and vegetables are 1.02-2.33 times ODCM, but fruits 0.9 times ODCM. Carbon content of grains, leafy vegetables, and fruits are 0.7-0.98 times ODCM, but root vegetables 1.49 times ODCM. This would result in the change of ingestion dose as much

  13. Depletion of fossil fuels and the impacts of global warming

    International Nuclear Information System (INIS)

    Hoel, M.; Kverndokk, S.

    1996-01-01

    This paper combines the theory of optimal extraction of exhaustible resources with the theory of greenhouse externalities, to analyze problems of global warming when the supply side is considered. The optimal carbon tax will initially rise but eventually fall when the externality is positively related to the stock of carbon in the atmosphere. It is shown that the tax will start falling before the stock of carbon in the atmosphere reaches its maximum. If there exists a non-polluting backstop technology, it will be optimal to extract and consume fossil fuels even when the price of fossil fuels is equal to the price of the backstop. The total extraction is the same as when the externality is ignored, but in the presence of the greenhouse effect, it will be optimal to slow the extraction and spread it over a longer period. If, on the other hand, the greenhouse externality depends on the rate of change in the atmospheric stock of carbon, the evolution of the optimal carbon tax is more complex. It can even be optimal to subsidize carbon emissions to avoid future rapid changes in the stock of carbon, and therefore future damages. 22 refs., 3 figs

  14. A sub-boiling distillation method for the preparation of low carbon content water from urine samples for tritium measurement by liquid scintillation counting

    International Nuclear Information System (INIS)

    Nogawa, Norio; Makide, Yoshihiro

    1999-01-01

    A new preparation method was developed for obtaining low carbon content water from urine samples for the measurement of tritium by a liquid scintillation counter. The method uses a simple and convenient subboiling distillation bottle. Many urine samples have been purified by this method and the change of tritium level in a tritium-handling radiation-worker was observed

  15. Fabrication of Metal Nanoparticle-Modified Screen Printed Carbon Electrodes for the Evaluation of Hydrogen Peroxide Content in Teeth Whitening Strips

    Science.gov (United States)

    Popa, Adriana; Abenojar, Eric C.; Vianna, Adam; Buenviaje, Czarina Y. A.; Yang, Jiahua; Pascual, Cherrie B.; Samia, Anna Cristina S.

    2015-01-01

    A laboratory experiment in which students synthesize Ag, Au, and Pt nanoparticles (NPs) and use them to modify screen printed carbon electrodes for the electroanalysis of the hydrogen peroxide content in commercially available teeth whitening strips is described. This experiment is designed for two 3-h laboratory periods and can be adapted for…

  16. Into the mire: A closer look at fossil fuel subsidies

    Directory of Open Access Journals (Sweden)

    Radoslaw (Radek Stefanski

    2016-03-01

    Full Text Available Threatened by climate change, governments the world over are attempting to nudge markets in the direction of less carbon-intensive energy. Perversely, many of these governments continue to subsidize fossil fuels, distorting markets and raising emissions. Determining how much money is involved is difficult, as neither the providers nor the recipients of those subsidies want to own up to them. This paper builds on a unique method to extract fossil fuel subsidies from patterns in countries’ carbon emission-to-GDP ratios. This approach is useful since it: 1 overcomes the problem of scarce data; 2 derives a wider and more comparable measure of subsidies than existing measures and 3 allows for the performance of counterfactuals which help measure the impact of subsidies on emissions and growth. The resultant 170-country, 30-year database finds that the financial and the environmental costs of such subsidies are enormous, especially in China and the U.S. The overwhelming majority of the world’s fossil fuel subsidies stem from China, the U.S. and the ex-USSR; as of 2010, this figure was $712 billion or nearly 80 per cent of the total world value of subsidies. For its part, Canada has been subsidizing rather than taxing fossil fuels since 1998. By 2010, Canadian subsidies sat at $13 billion, or 1.4 per cent of GDP. In that same year, the total global direct and indirect financial costs of all such subsidies amounted to $1.82 trillion, or 3.8 per cent of global GDP. Aside from the money saved, in 2010 a world without subsidies would have had carbon emissions 36 per cent lower than they actually were. Any government looking to ease strained budgets and make a significant (and cheap contribution to the fight against climate change must consider slashing fossil fuel subsidies. As the data show, this is a sound decision – fiscally and environmentally.

  17. Modelling Soil Carbon Content in South Patagonia and Evaluating Changes According to Climate, Vegetation, Desertification and Grazing

    Directory of Open Access Journals (Sweden)

    Pablo Luis Peri

    2018-02-01

    Full Text Available In Southern Patagonia, a long-term monitoring network has been established to assess bio-indicators as an early warning of environmental changes due to climate change and human activities. Soil organic carbon (SOC content in rangelands provides a range of important ecosystem services and supports the capacity of the land to sustain plant and animal productivity. The objectives in this study were to model SOC (30 cm stocks at a regional scale using climatic, topographic and vegetation variables, and to establish a baseline that can be used as an indicator of rangeland condition. For modelling, we used a stepwise multiple regression to identify variables that explain SOC variation at the landscape scale. With the SOC model, we obtained a SOC map for the entire Santa Cruz province, where the variables derived from the multiple linear regression models were integrated into a geographic information system (GIS. SOC stock to 30 cm ranged from 1.38 to 32.63 kg C m−2. The fitted model explained 76.4% of SOC variation using as independent variables isothermality, precipitation seasonality and vegetation cover expressed as a normalized difference vegetation index. The SOC map discriminated in three categories (low, medium, high determined patterns among environmental and land use variables. For example, SOC decreased with desertification due to erosion processes. The understanding and mapping of SOC in Patagonia contributes as a bridge across main issues such as climate change, desertification and biodiversity conservation.

  18. Geophysical Prediction Technology Based on Organic Carbon Content in Source Rocks of the Huizhou Sag, the South China Sea

    Directory of Open Access Journals (Sweden)

    Yang Wei

    2017-08-01

    Full Text Available Due to the high exploration cost, limited number of wells for source rocks drilling and scarce test samples for the Total Organic Carbon Content (TOC in the Huizhou sag, the TOC prediction of source rocks in this area and the assessment of resource potentials of the basin are faced with great challenges. In the study of TOC prediction, predecessors usually adopted the logging assessment method, since the data is only confined to a “point” and the regional prediction of the source bed in the seismic profile largely depends on the recognition of seismic facies, making it difficult to quantify TOC. In this study, we combined source rock geological characteristics, logging and seismic response and built the mathematical relation between quasi TOC curve and seismic data based on the TOC logging date of a single well and its internal seismic attribute. The result suggested that it was not purely a linear relationship that was adhered to by predecessors, but was shown as a complicated non-linear relationship. Therefore, the neural network algorithm and SVMs were introduced to obtain the optimum relationship between the quasi TOC curve and the seismic attribute. Then the goal of TOC prediction can be realized with the method of seismic inversion.

  19. Optimization of solid content, carbon/nitrogen ratio and food/inoculum ratio for biogas production from food waste.

    Science.gov (United States)

    Dadaser-Celik, Filiz; Azgin, Sukru Taner; Yildiz, Yalcin Sevki

    2016-12-01

    Biogas production from food waste has been used as an efficient waste treatment option for years. The methane yields from decomposition of waste are, however, highly variable under different operating conditions. In this study, a statistical experimental design method (Taguchi OA 9 ) was implemented to investigate the effects of simultaneous variations of three parameters on methane production. The parameters investigated were solid content (SC), carbon/nitrogen ratio (C/N) and food/inoculum ratio (F/I). Two sets of experiments were conducted with nine anaerobic reactors operating under different conditions. Optimum conditions were determined using statistical analysis, such as analysis of variance (ANOVA). A confirmation experiment was carried out at optimum conditions to investigate the validity of the results. Statistical analysis showed that SC was the most important parameter for methane production with a 45% contribution, followed by F/I ratio with a 35% contribution. The optimum methane yield of 151 l kg -1 volatile solids (VS) was achieved after 24 days of digestion when SC was 4%, C/N was 28 and F/I were 0.3. The confirmation experiment provided a methane yield of 167 l kg -1 VS after 24 days. The analysis showed biogas production from food waste may be increased by optimization of operating conditions. © The Author(s) 2016.

  20. Sanitary effects of fossil fuels; Effets sanitaires des combustibles fossiles

    Energy Technology Data Exchange (ETDEWEB)

    Nifenecker, H. [Centre National de la Recherche Scientifique (IN2P3/CNRS), 38 - Grenoble (France)

    2006-07-01

    In this compilation are studied the sanitary effects of fossil fuels, behavioral and environmental sanitary risks. The risks in connection with the production, the transport and the distribution(casting) are also approached for the oil(petroleum), the gas and the coal. Accidents in the home are evoked. The risks due to the atmospheric pollution are seen through the components of the atmospheric pollution as well as the sanitary effects of this pollution. (N.C.)

  1. Fossilized Mammalian Erythrocytes Associated With a Tick Reveal Ancient Piroplasms.

    Science.gov (United States)

    Poinar, George

    2017-07-01

    Ticks transmit a variety of pathogenic organisms to vertebrates, especially mammals. The fossil record of such associations is extremely rare. An engorged nymphal tick of the genus Ambylomma in Dominican amber was surrounded by erythrocytes from its mammalian host. Some of the exposed erythrocytes contained developmental stages of a hemoprotozoan resembling members of the Order Piroplasmida. The fossil piroplasm is described, its stages compared with those of extant piroplasms, and reasons provided why the mammalian host could have been a primate. The parasites were also found in the gut epithelial cells and body cavity of the fossil tick. Aside from providing the first fossil mammalian red blood cells and the first fossil intraerythrocytic hemoparasites, the present discovery shows that tick-piroplasm associations were already well established in the Tertiary. This discovery provides a timescale that can be used in future studies on the evolution of the Piroplasmida. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com Version of Record, first published online March 20, 2017 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.

  2. News technology utilization fossil fuel

    Directory of Open Access Journals (Sweden)

    Blišanová Monika

    2004-09-01

    Full Text Available Fossil fuel – “alternative energy“ is coal, petroleum, natural gas. Petroleum and natural gas are scarce resources, but they are delimited. Reserves petroleum will be depleted after 39 years and reserves natural gas after 60 years.World reserves coal are good for another 240 years. Coal is the most abundant fossil fuel. It is the least expensive energy source for generating electricity. Many environmental problems associated with use of coal:in coal production, mining creates environmental problems.On Slovakia representative coal only important internal fuel – power of source and coal is produced in 5 locality. Nowadays, oneself invest to new technology on utilization coal. Perspective solution onself shows UCG, IGCC.

  3. Clustering fossils in solid inflation

    Energy Technology Data Exchange (ETDEWEB)

    Akhshik, Mohammad, E-mail: m.akhshik@ipm.ir [Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2015-05-01

    In solid inflation the single field non-Gaussianity consistency condition is violated. As a result, the long tenor perturbation induces observable clustering fossils in the form of quadrupole anisotropy in large scale structure power spectrum. In this work we revisit the bispectrum analysis for the scalar-scalar-scalar and tensor-scalar-scalar bispectrum for the general parameter space of solid. We consider the parameter space of the model in which the level of non-Gaussianity generated is consistent with the Planck constraints. Specializing to this allowed range of model parameter we calculate the quadrupole anisotropy induced from the long tensor perturbations on the power spectrum of the scalar perturbations. We argue that the imprints of clustering fossil from primordial gravitational waves on large scale structures can be detected from the future galaxy surveys.

  4. Sanitary effects of fossil fuels

    International Nuclear Information System (INIS)

    Nifenecker, H.

    2006-01-01

    In this compilation are studied the sanitary effects of fossil fuels, behavioral and environmental sanitary risks. The risks in connection with the production, the transport and the distribution(casting) are also approached for the oil(petroleum), the gas and the coal. Accidents in the home are evoked. The risks due to the atmospheric pollution are seen through the components of the atmospheric pollution as well as the sanitary effects of this pollution. (N.C.)

  5. Extinction and the fossil record

    Science.gov (United States)

    Sepkoski, J. J. Jr; Sepkoski JJ, ,. J. r. (Principal Investigator)

    1994-01-01

    The author examines evidence of mass extinctions in the fossil record and searches for reasons for such large extinctions. Five major mass extinctions eliminated at least 40 percent of animal genera in the oceans and from 65 to 95 percent of ocean species. Questions include the occurrence of gradual or catastrophic extinctions, causes, environment, the capacity of a perturbation to cause extinctions each time it happens, and the possibility and identification of complex events leading to a mass extinction.

  6. GASEOUS EMISSIONS FROM FOSSIL FUELS AND BIOMASS COMBUSTION IN SMALL HEATING APPLIANCES

    Directory of Open Access Journals (Sweden)

    Daniele Dell'Antonia

    2012-06-01

    Full Text Available The importance of emission control has increased sharply due to the increased need of energy from combustion. However, biomass utilization in energy production is not free from problems because of physical and chemical characteristics which are substantially different from conventional energy sources. In this situation, the quantity and quality of emissions as well as used renewable sources as wood or corn grain are often unknown. To assess this problem the paper addresses the objectives to quantify the amount of greenhouse gases during the combustion of corn as compared to the emissions in fossil combustion (natural gas, LPG and diesel boiler. The test was carried out in Friuli Venezia Giulia in 2006-2008 to determine the air pollution (CO, NO, NO2, NOx, SO2 and CO2 from fuel combustion in family boilers with a power between 20-30 kWt. The flue gas emission was measured with a professional semi-continuous multi-gas analyzer, (Vario plus industrial, MRU air Neckarsulm-Obereisesheim. Data showed a lower emission of fossil fuel compared to corn in family boilers in reference to pollutants in the flue gas (NOx, SO2 and CO. In a particular way the biomass combustion makes a higher concentration of carbon monoxide (for an incomplete combustion because there is not a good mixing between fuel and air and nitrogen oxides (in relation at a higher content of nitrogen in herbaceous biomass in comparison to another fuel.

  7. An investigation of fossil bone mineral structure with neutron scattering

    International Nuclear Information System (INIS)

    Batdehmbehrehl, G.; Chultehm, D.; Sangaa, D.

    1999-01-01

    Using the neutron diffraction method a domination of low crystal syngonic (sp. gr. P63/m) phase Ca 5 [PO 4 ] 3 (OH, F, Cl) in the fossil dinosaur bone has been established. It is shown that the neutron diffraction method has large advantages in apatite phase of any vertebrates studies and in the case of carbonate phase x-ray method it becomes to be preferable. (author)

  8. Estimates of global, regional, and national annual CO{sub 2} emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950--1992

    Energy Technology Data Exchange (ETDEWEB)

    Boden, T.A.; Marland, G. [Oak Ridge National Lab., TN (United States); Andres, R.J. [University of Alaska, Fairbanks, AK (United States). Inst. of Northern Engineering

    1995-12-01

    This document describes the compilation, content, and format of the most comprehensive C0{sub 2}-emissions database currently available. The database includes global, regional, and national annual estimates of C0{sub 2} emissions resulting from fossil-fuel burning, cement manufacturing, and gas flaring in oil fields for 1950--92 as well as the energy production, consumption, and trade data used for these estimates. The methods of Marland and Rotty (1983) are used to calculate these emission estimates. For the first time, the methods and data used to calculate CO, emissions from gas flaring are presented. This C0{sub 2}-emissions database is useful for carbon-cycle research, provides estimates of the rate at which fossil-fuel combustion has released C0{sub 2} to the atmosphere, and offers baseline estimates for those countries compiling 1990 C0{sub 2}-emissions inventories.

  9. Carbon dioxide sequestration by mineral carbonation

    NARCIS (Netherlands)

    Huijgen, W.J.J.

    2007-01-01

    The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept

  10. Variation of the uranium monocarbide parameter with changes in the carbon content; Variations du parametre du monocarbure d'uranium en fonction de sa teneur en carbone

    Energy Technology Data Exchange (ETDEWEB)

    Magnier, P; Accary, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The authors show that the chemical species uranium monocarbide is only a particular composition of the uranium-carbon alloy phase containing between 48 and 50 atoms per cent of carbon, and that the crystalline parameter of this phase varies simultaneously from 4.956 to 4.961 Angstroms. (authors) [French] Les auteurs montrent que l'espece chimique monocarbure d'uranium n'est qu'une composition particuliere de la phase des alliages uranium carbone contenant entre 48 et 50 atomes pour cent de carbone et que le parametre cristallin de cette phase varie simultanement de 4.956 a 4.961 Angstroms.

  11. Carbon capture and sequestration (CCS)

    Science.gov (United States)

    2009-06-19

    Carbon capture and sequestration (or storage)known as CCShas attracted interest as a : measure for mitigating global climate change because large amounts of carbon dioxide (CO2) : emitted from fossil fuel use in the United States are potentiall...

  12. Effects of carbon source and carbon content on electrochemical performances of Li{sub 4}Ti{sub 5}O{sub 12}/C prepared by one-step solid-state reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hu Xuebu [College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, Sichuan 610066 (China); Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Lin Ziji [China National Quality Supervision and Inspection Center for Alcoholic Beverage Products and Processed Food, Luzhou, Sichuan 646100 (China); Yang Kerun [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Hua, Yongjian [China Aviation Lithium Battery Co. Ltd., Luoyang, Henan 471009 (China); Deng Zhenghua, E-mail: zhdeng@cioc.ac.cn [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China)

    2011-05-30

    Highlights: > A simple route to prepare the Li{sub 4}Ti{sub 5}O{sub 12}/C by one-step solid-state reaction. > Carbon source and carbon content are two important factors on the electrochemical performances of Li{sub 4}Ti{sub 5}O{sub 12}/C. > As-prepared Li{sub 4}Ti{sub 5}O{sub 12}/C under optimized conditions shows excellent electrochemical performances. - Abstract: Li{sub 4}Ti{sub 5}O{sub 12}/C composites were synthesized by one-step solid-state reaction method using four commonly used organic compounds or organic polymers as carbon source, i.e., polyacrylate acid (PAA), citric acid (CA), maleic acid (MA) and polyvinyl alcohol (PVA). The physical characteristics of Li{sub 4}Ti{sub 5}O{sub 12}/C composites were investigated by X-ray diffraction, electron microscopy, Raman spectroscopy, particle size distribution and thermogravimetry-derivative thermogravimetry techniques. Their electrochemical properties were characterized by cyclic voltammograms, electrochemical impedance spectra, constant current charge-discharge and rate charge-discharge. These analyses indicated that the carbon source and carbon content have a great effect on the physical and electrochemical performances of Li{sub 4}Ti{sub 5}O{sub 12}/C composites. An ideal carbon source and appropriate carbon content effectively improved the electrical contact between the Li{sub 4}Ti{sub 5}O{sub 12} particles, which enhanced the discharge capacity and rate capability of Li{sub 4}Ti{sub 5}O{sub 12}/C composites. PAA was the best carbon source for the synthesis of Li{sub 4}Ti{sub 5}O{sub 12}/C composites. When the carbon content was 3.49 wt.% (LiOH.H{sub 2}O/PAA molar ratio of 1), as-prepared Li{sub 4}Ti{sub 5}O{sub 12}/C showed the maximum discharge capacity. At 0.2 C, initial capacity of the optimized sample was 168.6 mAh g{sup -1} with capacity loss of 2.8% after 50 cycles. At 8 and 10 C, it showed discharge capacities of 143.5 and 132.7 mAh g{sup -1}, with capacity loss of 8.7 and 9.9% after 50 cycles

  13. One-dimensional fossil-like γ-Fe2O3@carbon nanostructure: preparation, structural characterization and application as adsorbent for fast and selective recovery of gold ions from aqueous solution

    Science.gov (United States)

    Gunawan, Poernomo; Xiao, Wen; Hao Chua, Marcus Wen; Poh-Choo Tan, Cheryl; Ding, Jun; Zhong, Ziyi

    2016-10-01

    One-dimensional (1D) magnetic nanostructures with high thermal stability have important industrial applications, but their fabrication remains a big challenge. Herein we demonstrate a scalable approach for the preparation of stable 1D γ-Fe2O3@carbon, which is also applicable for other metal oxide-core and carbon-shell nanostructures, such as 1D TiO2@carbon. One-dimensional ferric oxyhydroxide (α-FeO(OH)) was initially prepared by a hydrothermal method, followed by carbon coating through hydrothermal treatment of the resulting metal oxide in glucose solution. After calcination in N2 gas at 500 °C and subsequent exposure to air, the initial carbon-coated 1D α-Fe2O3 was converted to 1D γ-Fe2O3@carbon, which was very stable without any observed changes even after 1.5 years of storage under ambient conditions. The materials were then used as adsorbents and found to be highly selective towards Au (III) adsorption, of which the maximum adsorption capacity is about 600 mg Au/g sorbent (1132 mg Au/g carbon). The spent sorbent containing Au after adsorption can be readily collected by applying a magnetic field due to the presence of the magnetic core, and the adsorbed Au particles are subsequently recovered after the combustion and dissolution of the sorbent. This work demonstrates not only a facile approach to the fabrication of robust 1D magnetic materials with a stable carbon shell, but also a possible cyanide-free process for the fast and selective recovery of gold from electronic waste and industrial water.

  14. Determination of the carbon, hydrogen and nitrogen contents of alanine and their uncertainties using the certified reference material L-alanine (NMIJ CRM 6011-a).

    Science.gov (United States)

    Itoh, Nobuyasu; Sato, Ayako; Yamazaki, Taichi; Numata, Masahiko; Takatsu, Akiko

    2013-01-01

    The carbon, hydrogen, and nitrogen (CHN) contents of alanine and their uncertainties were estimated using a CHN analyzer and the certified reference material (CRM) L-alanine. The CHN contents and their uncertainties, as measured using the single-point calibration method, were 40.36 ± 0.20% for C, 7.86 ± 0.13% for H, and 15.66 ± 0.09% for N; the results obtained using the bracket calibration method were also comparable. The method described in this study is reasonable, convenient, and meets the general requirement of having uncertainties ≤ 0.4%.

  15. Probing atomic scale transformation of fossil dental enamel using Fourier transform infrared and nuclear magnetic resonance spectroscopy: a case study from the Tugen Hills (Rift Gregory, Kenya).

    Science.gov (United States)

    Yi, Haohao; Balan, Etienne; Gervais, Christel; Ségalen, Loïc; Roche, Damien; Person, Alain; Fayon, Franck; Morin, Guillaume; Babonneau, Florence

    2014-09-01

    A series of fossil tooth enamel samples was investigated by Fourier transform infrared (FTIR) spectroscopy, (13)C and (19)F magic-angle spinning nuclear magnetic resonance (MAS NMR) and scanning electron microscopy (SEM). Tooth remains were collected in Mio-Pliocene deposits of the Tugen Hills in Kenya. Significant transformations were observed in fossil enamel as a function of increasing fluorine content (up to 2.8wt.%). FTIR spectroscopy revealed a shift of the ν1 PO4 stretching band to higher frequency. The ν2 CO3 vibrational band showed a decrease in the intensity of the primary B-type carbonate signal, which was replaced by a specific band at 864cm(-1). This last band was ascribed to a specific carbonate environment in which the carbonate group is closely associated to a fluoride ion. The occurrence of this carbonate defect was consistently attested by the observation of two different fluoride signals in the (19)F NMR spectra. One main signal, at ∼-100ppm, is related to structural F ions in the apatite channel and the other, at -88ppm, corresponds to the composite defect. These spectroscopic observations can be understood as resulting from the mixture of two phases: biogenic hydroxylapatite (bioapatite) and secondary fluorapatite. SEM observations of the most altered sample confirmed the extensive replacement of the bioapatite by fluorapatite, resulting from the dissolution of the primary bioapatite followed by the precipitation of carbonate-fluorapatite. The ν2 CO3 IR bands can be efficiently used to monitor the extent of this type of bioapatite transformation during fossilization. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. High-temperature oxidation behavior of dense SiBCN monoliths: Carbon-content dependent oxidation structure, kinetics and mechanisms

    International Nuclear Information System (INIS)

    Li, Daxin; Yang, Zhihua; Jia, Dechang; Wang, Shengjin; Duan, Xiaoming; Zhu, Qishuai; Miao, Yang; Rao, Jiancun; Zhou, Yu

    2017-01-01

    Highlights: •The scale growth for all investigated monoliths at 1500 °C cannot be depicted by a linear or parabolic rate law. •The carbon-rich monoliths oxidize at 1500 °C according to a approximately linear weight loss equation. •The excessive carbon in SiBCN monoliths deteriorates the oxidation resistance. •The oxidation resistance stems from the characteristic oxide structures and increased oxidation resistance of BN(C). -- Abstract: The high temperature oxidation behavior of three SiBCN monoliths: carbon-lean SiBCN with substantial Si metal, carbon-moderate SiBCN and carbon-rich SiBCN with excessive carbon, was investigated at 1500 °C for times up to15 h. Scale growth for carbon-lean and −moderate monoliths at 1500 °C cannot be described by a linear or parabolic rate law, while the carbon-rich monoliths oxidize according to a approximately linear weight loss equation. The microstructures of the oxide scale compose of three distinct layers. The passivating layer of carbon and boron containing amorphous SiO 2 and increased oxidation resistance of BN(C) both benefit the oxidation resistance.

  17. Closing carbon cycles

    NARCIS (Netherlands)

    Patel, Martin

    1999-01-01

    Fossil fuels are used as raw materials for the manufacture of synthetic organic materials, e.g. plastics, fibres, synthetic rubber, paints, solvents, fertilisers, surfactants, lubricants and bitumen. Since fossil carbon is embodied in these products they may be particularly relevant to climate

  18. Application of laser-produced-plasmas to determination of carbon content in steel; Aplicacion de los plasmas generados por laser a la determinacion de carbono en aceros

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, M; Aragon, C; Aguilera, J A; Campos, J

    1994-07-01

    This paper describes an analytical method to determine carbon content in solid and molten steel. It is based on the study of the emission spectrum from a Nd-YAG laser produced plasma. The light emitted from the plasma is focused to the entrance slit of a spectrometer and detected by an OMA III system. For every laser pulse an spectral range of 100 A are recorded. With the use of time-resolved spectroscopy a precision of 1.6 % and a detection limit of 65 ppm of carbon content in steel have been obtained. These values are similar to those of other accurate conventional techniques but using optics fiber and laser excitation it is possible to made sample calibrations in hostile environments. Also, as the analysis are made in real time changes in sample composition can be measured without stopping production processes. (Author) 26 refs.

  19. Effect of carbon content on formation of bimodal microstructure and mechanical properties of low-carbon steels subjected to heavy-reduction single-pass hot/warm deformation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyung-Won, E-mail: wonipark@iis.u-tokyo.ac.jp [Graduate School of Engineering, The University of Tokyo, Komaba 4-6-1, Meguro-ku 153-8505, Tokyo (Japan); Yanagimoto, Jun [Institute of Industrial Science, The University of Tokyo, Komaba 4-6-1, Meguro-ku 153-8505, Tokyo (Japan)

    2014-06-01

    A compression test simulating heavy-reduction single-pass rolling was conducted to investigate the microstructural evolution based on the formation of a bimodal structure and the mechanical properties of 0.01% and 0.1% carbon steels and niobium steel. When thermomechanical processing was conducted near and above the critical transformation temperature (A{sub c3}), microstructures of all steels were significantly refined and consisted of equiaxed grains without elongated grains. Nevertheless, these microstructures showed weak or no formation of the bimodal structure or coarse grains with decreasing carbon content, while they showed bimodal structure formation when 0.2% carbon steel was used in our previous research. The average grain size of Nb steel was about 2 μm and its microstructure was uniformly refined. These may be attributed to a decrease in the number of nucleation sites with decreasing carbon content in low-carbon steels and the occurrence of nucleation at grain boundaries as well as in grain interiors in Nb steel during processing. Mechanical properties of all steels deformed above the critical transformation temperature exhibited high performance characteristics with superior strength and marked elongation. Their fractographs indicated ductile fracture, which was revealed by SEM observation after a tensile test.

  20. Prudence in a fossil generation

    International Nuclear Information System (INIS)

    Ruschak, R.R.; Yost, R.E.

    1991-01-01

    During the last decade, regulatory agencies have increasingly required that to be reimbursed for an investment in facilities, utilities must first prove their generating facility construction projects were prudently managed. The proof was almost always solicited when the plants were nearing completion. Utilities failing this retrospective prudence test have often suffered severe financial penalties. Thus far fossil plants have been spared the brunt of the prudence challenge. However, this situation may change. Regulatory agencies are honing the prudence concept into a broad tool. Application of this regulatory method is not likely to wane but rather just change its focus - from that of nuclear to other large utility expenditures. The primary ones being fossil construction, fuel purchases, and transmission facilities. For new plant construction to begin again and successfully pass the prudence challenge, the industry must learn from the troubles of the nuclear era, and change the way that decisions are made, documented and archived. Major decisions resulting in the commitment of millions of dollars over extended time periods (and governmental administrations) must be appropriately structured, packaged, collated to key issues and stored for ease of retrieval when the Prudence questions are asked. This paper describes how utilities can anticipate fossil-related prudence and shield themselves from extensive retrospective reconstruction of decisions made years ago. Through the establishment of a formal program of prudence safeguards, utility management can reduce its exposure to potentially adverse prudence reviews. In many cases, the resulting focus on, and improvements in, the decision making process can have beneficial side effects - such as better decisions that lead to lower project costs

  1. Dinosaur fossils predict body temperatures.

    Directory of Open Access Journals (Sweden)

    James F Gillooly

    2006-07-01

    Full Text Available Perhaps the greatest mystery surrounding dinosaurs concerns whether they were endotherms, ectotherms, or some unique intermediate form. Here we present a model that yields estimates of dinosaur body temperature based on ontogenetic growth trajectories obtained from fossil bones. The model predicts that dinosaur body temperatures increased with body mass from approximately 25 degrees C at 12 kg to approximately 41 degrees C at 13,000 kg. The model also successfully predicts observed increases in body temperature with body mass for extant crocodiles. These results provide direct evidence that dinosaurs were reptiles that exhibited inertial homeothermy.

  2. Developing fossil fuel based technologies

    International Nuclear Information System (INIS)

    Manzoori, A.R.; Lindner, E.R.

    1991-01-01

    Some of the undesirable effects of burning fossil fuels in the conventional power generating systems have resulted in increasing demand for alternative technologies for power generation. This paper describes a number of new technologies and their potential to reduce the level of atmospheric emissions associated with coal based power generation, such as atmospheric and pressurized fluid bed combustion systems and fuel cells. The status of their development is given and their efficiency is compared with that of conventional pc fired power plants. 1 tab., 7 figs

  3. Financial subsidies to the Australian fossil fuel industry

    International Nuclear Information System (INIS)

    Riedy, Chris; Diesendorf, Mark

    2003-01-01

    A common claim during international greenhouse gas reduction negotiations has been that domestic emissions cuts will harm national economies. This argument fails to consider the distorting effect of existing financial subsidies and associated incentives to fossil fuel production and consumption provided by governments in most developed countries. These subsidies support a fossil fuel energy sector that is the major contributor to global greenhouse gas emissions and conflict with attempts to expand the role of sustainable energy technologies. Reform of these types of subsidies has the potential to provide substantial gains in economic efficiency as well as reductions in carbon dioxide emissions--a 'no regrets' outcome for the economy and the environment. This paper examines financial subsidies to fossil fuel production and consumption in Australia and estimates the magnitude of the subsidies. Subsidies and associated incentives to fossil fuel production and consumption in Australia are similar to those in the United States and the other countries that have pushed for increased 'flexibility' during international negotiations

  4. Differential Effects of Legume Species on the Recovery of Soil Microbial Communities, and Carbon and Nitrogen Contents, in Abandoned Fields of the Loess Plateau, China

    Science.gov (United States)

    Li, Jin Hua; Jiao, Shu Mei; Gao, Rong Qing; Bardgett, Richard D.

    2012-12-01

    Plant-soil interactions are known to influence a wide range of ecosystem-level functions. Moreover, the recovery of these functions is of importance for the successful restoration of soils that have been degraded through intensive and/or inappropriate land use. Here, we assessed the effect of planting treatments commonly used to accelerate rates of grassland restoration, namely introduction of different legume species Medicago sativa, Astragalus adsurgens, Melilotus suaveolens, on the recovery of soil microbial communities and carbon and nitrogen contents in abandoned fields of the Loess Plateau, China. The results showed effects were species-specific, and either positive, neutral or negative depending on the measure and time-scale. All legumes increased basal respiration and metabolic quotient and had a positive effect on activity and functional diversity of the soil microbial community, measured using Biolog EcoPlate. However, soil under Astragalus adsurgens had the highest activity and functional diversity relative to the other treatments. Soil carbon and nitrogen content and microbial biomass were effectively restored in 3-5 years by introducing Medicago sativa and Astragalus adsurgens into early abandoned fields. Soil carbon and nitrogen content were retarded in 3-5 years and microbial biomass was retarded in the fifth year by introducing Melilotus suaveolens. Overall, the restoration practices of planting legumes can significantly affect soil carbon and nitrogen contents, and the biomass, activity, and functional diversity of soil microbial community. Therefore, we propose certain legume species could be used to accelerate ecological restoration of degraded soils, hence assist in the protection and preservation of the environment.

  5. Isotopic study of some fossil and actual hydrothermal systems

    International Nuclear Information System (INIS)

    Demont, J.M.

    1981-07-01

    Oxygen and hydrogen isotopic compositions of rocks from the INAG no 1 drillhole provide evidence of a fossil hydrothermal system in the Ceyssat region of the Massif Central. Oxygen isotope temperatures for the mineral paragenesis are about 275 0 C and the water is of marine origin. Measurements have also been made of delta 13 C values of dissolved carbon and gaseous CO 2 from several hot springs in the Pyrenees and Massif Central. The carbon isotopic composition of the total systems have been calculated from the gas-liquid ratios at the emergence sites and these results are discussed in terms of the origin of the carbon. Most of the hydrothermal carbon is of deep origin. The observed variations in isotopic compositions may be explained by the behavior of the fluids during their ascent to the surface [fr

  6. Effects of New Fossil Fuel Developments on the Possibilities of Meeting 2C Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Meindertsma, W.; Blok, K.

    2012-12-15

    Recent years have seen an increasing activity in developing new fossil fuel production capacity. This includes unconventional fossil fuels, such as tar sands and shale gas, fossil fuels from remote locations, and fossil fuels with a very large increase in production in the near future. In this report, the impact of such developments on our ability to mitigate climate change is investigated. Our inventory shows that the new fossil fuel developments currently underway consist of 29,400 billion cubic meters of natural gas, 260,000 million barrels of oil and 49,600 million tonnes of coal. The development of these new fossil fuels would result in emissions of 300 billion tonnes of CO2 -equivalent (CO2e) from 2012 until 2050. Until 2050, a 'carbon budget' of 1550 billion tonnes CO2e is still available if we want to of keep global warming below 2C with a 50% probability. For a 75% probability to stay below 2C this budget is only 1050 billion tonnes CO2e. So, the new fossil fuel developments identified in this report consume 20-33% of the remaining carbon budget until 2050. In a scenario where the new fossil fuels are developed, we need to embark on a rapid emission reductions pathway at the latest in 2019 in order to meet the 50% probability carbon budget. Avoiding the development of new fossil fuels will give us until 2025 to start further rapid emission reductions. These calculations are based on the assumption that the maximum emission reduction rate is 4% per year and that the maximum change in emission trend is 0.5 percentage point per year. The starting year for rapid emission reductions depends on the choice of these parameters. A sensitivity analysis shows that, in all cases, refraining from new fossil fuel development allows for a delay of 5 to 8 years before we should embark on a rapid emission reduction pathway. The high investments required for developing new fossil fuels lead to a lock in effect; once developed, these fossil fuels need to be

  7. Fossil energy program. Summary document

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-05-01

    This program summary document presents a comprehensive overview of the research, development, and demonstration (RD and D) activities that will be performed in FY 1981 by the Assistant Secretary for Fossil Energy (ASFE), US Department of Energy (DOE). The ASFE technology programs for the fossil resources of coal, petroleum (including oil shale) and gas have been established with the goal of making substantive contributions to the nation's future supply and efficienty use of energy. On April 29, 1977, the Administration submitted to Congress the National Energy Plan (NEP) and accompanying legislative proposals designed to establish a coherent energy policy structure for the United States. Congress passed the National Energy Act (NEA) on October 15, 1978, which allows implementation of the vital parts of the NEP. The NEP was supplemented by additional energy policy statements culminating in the President's address on July 15, 1979, presenting a program to further reduce dependence on imported petroleum. The passage of the NEA-related energy programs represent specific steps by the Administration and Congress to reorganize, redirect, and clarify the role of the Federal Government in the formulation and execution of national energy policy and programs. The energy technology RD and D prog4rams carried out by ASFE are an important part of the Federal Government's effort to provide the combination and amounts of energy resources needed to ensure national security and continued economic growth.

  8. Biogenic carbon in combustible waste: Waste composition, variability and measurement uncertainty

    DEFF Research Database (Denmark)

    Larsen, Anna Warberg; Fuglsang, Karsten; Pedersen, Niels H.

    2013-01-01

    described in the literature. This study addressed the variability of biogenic and fossil carbon in combustible waste received at a municipal solid waste incinerator. Two approaches were compared: (1) radiocarbon dating (14C analysis) of carbon dioxide sampled from the flue gas, and (2) mass and energy......, the measurement uncertainties related to the two approaches were determined. Two flue gas sampling campaigns at a full-scale waste incinerator were included: one during normal operation and one with controlled waste input. Estimation of carbon contents in the main waste types received was included. Both the 14C...... method and the balance method represented promising methods able to provide good quality data for the ratio between biogenic and fossil carbon in waste. The relative uncertainty in the individual experiments was 7–10% (95% confidence interval) for the 14C method and slightly lower for the balance method....

  9. Role of non-fossil energy in meeting China's energy and climate target for 2020

    International Nuclear Information System (INIS)

    Zhou, Sheng; Tong, Qing; Yu, Sha; Wang, Yu; Chai, Qimin; Zhang, Xiliang

    2012-01-01

    China is the largest energy consumer and CO 2 emitter in the world. The Chinese government faces growing challenges of ensuring energy security and reducing greenhouse gas emissions. To address these two issues, the Chinese government has announced two ambitious domestic indicative autonomous mitigation targets for 2020: increasing the ratio of non-fossil energy to 15% and reducing carbon dioxide emissions per unit of GDP by 40–45% from 2005 levels. To explore the role of non-fossil energy in achieving these two targets, this paper first provides an overview of current status of non-fossil energy development in China; then gives a brief review of GDP and primary energy consumption; next assesses in detail the role of the non-fossil energy in 2020, including the installed capacity and electricity generation of non-fossil energy sources, the share and role of non-fossil energy in the electricity structure, emissions reduction resulting from the shift to non-fossil energy, and challenges for accomplishing the mitigation targets in 2020; finally, conclusions and policy measures for non-fossil energy development are proposed.

  10. Erratum: Retraction Note to: Effect of Carbon Content on the Electrical Conductivity of Carbon Black-Filled PMC with Various Matrices

    Science.gov (United States)

    Shin, Soon-Gi

    2018-03-01

    The Editor-in-Chief and Editorial Board of Electronic Materials Letters have retracted this article [1] because its contents have been previously published by Miyasaka et al. [2]. The contents of this article are therefore redundant. Author Soon-Gi Shin has not responded to correspondence from the Editor about this retraction.

  11. Microbial Biotechnology 2020; microbiology of fossil fuel resources.

    Science.gov (United States)

    Head, Ian M; Gray, Neil D

    2016-09-01

    This roadmap examines the future of microbiology research and technology in fossil fuel energy recovery. Globally, the human population will be reliant on fossil fuels for energy and chemical feedstocks for at least the medium term. Microbiology is already important in many areas relevant to both upstream and downstream activities in the oil industry. However, the discipline has struggled for recognition in a world dominated by geophysicists and engineers despite widely known but still poorly understood microbially mediated processes e.g. reservoir biodegradation, reservoir souring and control, microbial enhanced oil recovery. The role of microbiology is even less understood in developing industries such as shale gas recovery by fracking or carbon capture by geological storage. In the future, innovative biotechnologies may offer new routes to reduced emissions pathways especially when applied to the vast unconventional heavy oil resources formed, paradoxically, from microbial activities in the geological past. However, despite this potential, recent low oil prices may make industry funding hard to come by and recruitment of microbiologists by the oil and gas industry may not be a high priority. With regards to public funded research and the imperative for cheap secure energy for economic growth in a growing world population, there are signs of inherent conflicts between policies aimed at a low carbon future using renewable technologies and policies which encourage technologies which maximize recovery from our conventional and unconventional fossil fuel assets. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  12. Carbon dioxide adsorption on micro-mesoporous composite materials of ZSM-12/MCM-48 type: The role of the contents of zeolite and functionalized amine

    International Nuclear Information System (INIS)

    2CEM, São Cristovão/SE (Brazil))" data-affiliation=" (Federal University of Sergipe, Materials Science and Engineering Postgraduate Program P2CEM, São Cristovão/SE (Brazil))" >Santos, S.C.G.; Pedrosa, A.M.Garrido; Souza, M.J.B.; Cecilia, J.A.; Rodríguez-Castellón, E.

    2015-01-01

    Highlights: • Synthesis of the micro-mesoporous composite materials of ZSM-12/MCM-48 type. • Application of these adsorbents in the carbon dioxide adsorption. • Effects of the contents of zeolite and amino group in the material surface on the CO 2 capture efficiency. - Abstract: In this study ZSM-12/MCM-48 adsorbents have been synthesized at three ZSM-12 content, and also were functionalizated with amine groups by grafting. All the adsorbents synthesized were evaluated for CO 2 capture. The X-ray diffraction analysis of the ZSM-12/MCM-48 composite showed the main characteristic peaks of ZSM-12 and MCM-48, and after the functionalization, the structure of MCM-48 on the composite impregnated was affected due amine presence. For the composites without amine, the ZSM-12 content was the factor determining in the adsorption capacity of CO 2 and for the composites with amine the amount of amine was that influenced in the adsorption capacity

  13. Innovative Process to Enrich Carbon Content of EFB-Derived Biochar as an Alternative Energy Source in Ironmaking

    Directory of Open Access Journals (Sweden)

    Hadi Purwanto

    2018-01-01

    Full Text Available This paper describes the mechanism of a developed process—an integrated pyrolysis-tar decomposition process—to produce oil palm empty fruit bunch- (EFB- derived biochar with additional solid carbon within the biochar bodies, produced by decomposition of tar vapor on its pore surface, using the chemical vapor infiltration (CVI method. The product, carbon-infiltrated biochar, was characterized to investigate the possibility to be used as partial coke breeze replacement in ironmaking. Carbon-infiltrated biochar is proposed to be utilized for a sintering process that could reduce the consumption of coke and CO2 emission in iron-steel industry.

  14. Determination of carbon content of UO2, (U, Gd)O2 and (U, Pu)O2 powders and sintered pellets - Combustion in a high-frequency induction furnace -Infrared absorption spectrometry

    International Nuclear Information System (INIS)

    2008-01-01

    This International Standard describes a method for determining the carbon content in UO 2 , (U,Gd)O 2 and (U,Pu)O 2 powder and sintered pellets by combustion in an induction furnace and infrared absorption spectroscopy measurement. It is applicable for determining 10 μg/g to 500 μg/g of carbon in UO 2 , (U,Gd)O 2 and (U,Pu)O 2 powder and pellets. The sample is heated to a temperature above 1500 deg. C in an induction furnace, under pure oxygen atmosphere, to convert any carbon compounds to carbon dioxide gas. The resulting carbon dioxide gas is filtered and dried before measurement using infrared spectroscopy to measure the carbon dioxide signal at 2350 cm -1 . The result is converted into the carbon content of the material analysed

  15. Testing of an automated online EA-IRMS method for fast and simultaneous carbon content and stable isotope measurement of aerosol samples

    Science.gov (United States)

    Major, István; Gyökös, Brigitta; Túri, Marianna; Futó, István; Filep, Ágnes; Hoffer, András; Molnár, Mihály

    2016-04-01

    Comprehensive atmospheric studies have demonstrated that carbonaceous aerosol is one of the main components of atmospheric particulate matter over Europe. Various methods, considering optical or thermal properties, have been developed for quantification of the accurate amount of both organic and elemental carbon constituents of atmospheric aerosol. The aim of our work was to develop an alternative fast and easy method for determination of the total carbon content of individual aerosol samples collected on prebaked quartz filters whereby the mass and surface concentration becomes simply computable. We applied the conventional "elemental analyzer (EA) coupled online with an isotope ratio mass spectrometer (IRMS)" technique which is ubiquitously used in mass spectrometry. Using this technique we are able to measure simultaneously the carbon stable isotope ratio of the samples, as well. During the developing process, we compared the EA-IRMS technique with an off-line catalytic combustion method worked out previously at Hertelendi Laboratory of Environmental Studies (HEKAL). We tested the combined online total carbon content and stable isotope ratio measurement both on standard materials and real aerosol samples. Regarding the test results the novel method assures, on the one hand, at least 95% of carbon recovery yield in a broad total carbon mass range (between 100 and 3000 ug) and, on the other hand, a good reproducibility of stable isotope measurements with an uncertainty of ± 0.2 per mill. Comparing the total carbon results obtained by the EA-IRMS and the off-line catalytic combustion method we found a very good correlation (R2=0.94) that proves the applicability of both preparation method. Advantages of the novel method are the fast and simplified sample preparation steps and the fully automated, simultaneous carbon stable isotope ratio measurement processes. Furthermore stable isotope ratio results can effectively be applied in the source apportionment

  16. Origin and monitoring of pollutants in fossil-fuel flames

    International Nuclear Information System (INIS)

    Chigier, N.A.

    1976-01-01

    A review is given of the origin of pollutants in fossil-fuel flames. Burning of fossil fuels is the major cause of air pollution and significant reductions in levels of environmental pollution can be achieved by more effective control of combustion systems. The chemical kinetics of formation of unburned hydrocarbons, oxides of nitrogen, carbon monoxide and particulate matter are described, as well as the reactions which can lead to oxidation and destruction of these pollutants within the flame. The important influence of mixing and aerodynamics is discussed, together with methods of mathematical modelling and prediction methods. Practical problems arising in gas turbine engines, spark ignition engines and diesel engines are investigated in order to minimize the emission of pollutants while preserving fuel economy. (author)

  17. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia during the last decade.

    Science.gov (United States)

    O'Sullivan, Michael; Rap, Alex; Reddington, Carly; Spracklen, Dominick; Buermann, Wolfgang

    2016-04-01

    The global terrestrial carbon sink has increased since the start of this century at a time of rapidly growing carbon dioxide emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning have increased the diffuse fraction of incoming solar radiation and the efficiency of photosynthesis leading to increased plant carbon uptake. Using a combination of atmospheric and biospheric models, we find that changes in diffuse light associated with fossil fuel aerosol emission accounts for only 2.8% of the increase in global net primary production (1.221 PgC/yr) over the study period 1998 to 2007. This relatively small global signal is however a result of large regional compensations. Over East Asia, the strong increase in fossil fuel emissions contributed nearly 70% of the increased plant carbon uptake (21 TgC/yr), whereas the declining fossil fuel aerosol emissions in Europe and North America contributed negatively (-16% and -54%, respectively) to increased plant carbon uptake. At global scale, we also find the CO2 fertilization effect on photosynthesis to be the dominant driver of increased plant carbon uptake, in line with previous studies. These results suggest that further research into alternative mechanisms by which fossil fuel emissions could increase carbon uptake, such as nitrogen deposition and carbon-nitrogen interactions, is required to better understand a potential link between the recent changes in fossil fuel emissions and terrestrial carbon uptake.

  18. Paleoradiology. Imaging mummies and fossils

    Energy Technology Data Exchange (ETDEWEB)

    Chhem, Rethy K. [Western Ontario Univ. London Health Sciences Centre, ON (Canada). Dept. of Diagnostic Radiology and Nuclear Medicine; Brothwell, Don R. [York Univ. (United Kingdom). Dept. of Archaeology

    2008-07-01

    This is an important work on a topic of huge interest to archaeologists and related scientists, since the use of imaging techniques in the field has been expanding rapidly in recent decades. Paleoradiology involves the use of X-rays and advanced medical imaging modalities to evaluate ancient human and animal skeletons as well as biological materials from archaeological sites. Paleoradiological studies have been performed on mummies, skeletal remains and fossils to determine their sex and age at death. Diagnostic paleoradiology is the use of X-ray studies to detect ancient diseases. The broad range of themes and imaging techniques in this volume reflects four decades of research undertaken by Don Brothwell in the fields of anthropology, human paleopathology, and zooarchaeology, combined with two decades of skeletal radiology experience during which Rethy Chhem read over 150,000 skeletal X-ray and CT studies. (orig.)

  19. Paleoradiology. Imaging mummies and fossils

    International Nuclear Information System (INIS)

    Chhem, Rethy K.; Brothwell, Don R.

    2008-01-01

    This is an important work on a topic of huge interest to archaeologists and related scientists, since the use of imaging techniques in the field has been expanding rapidly in recent decades. Paleoradiology involves the use of X-rays and advanced medical imaging modalities to evaluate ancient human and animal skeletons as well as biological materials from archaeological sites. Paleoradiological studies have been performed on mummies, skeletal remains and fossils to determine their sex and age at death. Diagnostic paleoradiology is the use of X-ray studies to detect ancient diseases. The broad range of themes and imaging techniques in this volume reflects four decades of research undertaken by Don Brothwell in the fields of anthropology, human paleopathology, and zooarchaeology, combined with two decades of skeletal radiology experience during which Rethy Chhem read over 150,000 skeletal X-ray and CT studies. (orig.)

  20. Retrofitting for fossil fuel flexibility

    International Nuclear Information System (INIS)

    Newell, J.; Trueblood, R.C.; Lukas, R.W.; Worster, C.M.; Marx, P.D.

    1991-01-01

    Described in this paper are two fossil plant retrofits recently completed by the Public Service Company of New Hampshire that demonstrate the type of planning and execution required for a successful project under the current regulatory and budget constraints. Merrimack Units 1 and 2 are 120 MW and 338 MW nominal cyclone-fired coal units in Bow, New Hampshire. The retrofits recently completed at these plants have resulted in improved particulate emissions compliance, and the fuel flexibility to allow switching to lower sulphur coals to meet current and future SO 2 emission limits. Included in this discussion are the features of each project including the unique precipitator procurement approach for the Unit 1 Retrofit, and methods used to accomplish both retrofits within existing scheduled maintenance outages through careful planning and scheduling, effective use of pre-outage construction, 3-D CADD modeling, modular construction and early procurement. Operating experience while firing various coals in the cyclone fired boilers is also discussed

  1. Spatial prediction of Soil Organic Carbon contents in croplands, grasslands and forests using environmental covariates and Generalized Additive Models (Southern Belgium)

    Science.gov (United States)

    Chartin, Caroline; Stevens, Antoine; van Wesemael, Bas

    2015-04-01

    Providing spatially continuous Soil Organic Carbon data (SOC) is needed to support decisions regarding soil management, and inform the political debate with quantified estimates of the status and change of the soil resource. Digital Soil Mapping techniques are based on relations existing between a soil parameter (measured at different locations in space at a defined period) and relevant covariates (spatially continuous data) that are factors controlling soil formation and explaining the spatial variability of the target variable. This study aimed at apply DSM techniques to recent SOC content measurements (2005-2013) in three different landuses, i.e. cropland, grassland, and forest, in the Walloon region (Southern Belgium). For this purpose, SOC databases of two regional Soil Monitoring Networks (CARBOSOL for croplands and grasslands, and IPRFW for forests) were first harmonized, totalising about 1,220 observations. Median values of SOC content for croplands, grasslands, and forests, are respectively of 12.8, 29.0, and 43.1 g C kg-1. Then, a set of spatial layers were prepared with a resolution of 40 meters and with the same grid topology, containing environmental covariates such as, landuses, Digital Elevation Model and its derivatives, soil texture, C factor, carbon inputs by manure, and climate. Here, in addition to the three classical texture classes (clays, silt, and sand), we tested the use of clays + fine silt content (particles < 20 µm and related to stable carbon fraction) as soil covariate explaining SOC variations. For each of the three land uses (cropland, grassland and forest), a Generalized Additive Model (GAM) was calibrated on two thirds of respective dataset. The remaining samples were assigned to a test set to assess model performance. A backward stepwise procedure was followed to select the relevant environmental covariates using their approximate p-values (the level of significance was set at p < 0.05). Standard errors were estimated for each of

  2. Content and carbon stocks in labile and recalcitrant organic matter of the soil under crop-livestock integration in Cerrado

    Directory of Open Access Journals (Sweden)

    Itaynara Batista

    2013-12-01

    Full Text Available The study of organic matter and its compartments and their relationship with management, aims to develop strategies for increasing their levels in soils and better understanding of its dynamics. This work aimed to evaluate the fractions of soil organic matter and their carbon stocks in different soil cover system in crop-livestock integration and native Cerrado vegetation. The study was conducted at the farm Cabeceira, Maracajú – MS, sample area have the following history: soybean/corn + brachiaria/cotton/oat + pasture/soybean/formation of pasture/grazing, sampling was carried out in two seasons, dry (May/2009 and rainy (March 2010, in the dry season, crops present were: pasture, corn and cotton + brachiaria and in the rainy season were corn, cotton and soybeans, so the areas in the two evaluation periods were: pasture / maize + brachiaria / cotton, cotton / soybean area and a native of Savanna. Was performed to determine the exchangeable cations, particle size analysis, bulk density, organic carbon, particle size fractionation of organic matter of the soil with the quantification of particulate organic carbon (POC and organic carbon associated with minerals (OCam. Was also quantified the carbon stock and size fractions. The area of pasture / maize showed higher carbon stock in the particulate fraction in the topsoil. The area of cotton / soy due to its lower clay, showed the greatest loss of carbon. Because of the areas have the same history, the stock of more recalcitrant fraction was not sensitive to variations in coverage. The POC fraction appears more sensitive to different soil covers and seasonality.

  3. Negative-ion production on carbon materials in hydrogen plasma : influence of the carbon hybridization state and the hydrogen content on H- yield

    NARCIS (Netherlands)

    Ahmad, A.; Pardanaud, C.; Carrère, M.; Layet, J.M.; Gicquel, A.; Kumar, P.; Eon, D.; Jaoul, C.; Engeln, R.A.H.; Cartry, G.

    2014-01-01

    Highly oriented polycrystalline graphite (HOPG), boron-doped diamond (BDD), nanocrystalline diamond, ultra-nanocrystalline diamond and diamond-like carbon surfaces are exposed to low-pressure hydrogen plasma in a 13.56 MHz plasma reactor. Relative yields of surface-produced H- ions due to

  4. Comparison of The Performance of Proton Exchange Membrane Fuel Cell (PEMFC Electrodes with Different Carbon Powder Content and Methods of Manufacture

    Directory of Open Access Journals (Sweden)

    Dedi Rohendi

    2016-11-01

    Full Text Available Carbon powder in the gas diffusion layer (GDL contained in the membrane electrode assembly (MEA has an important role in the flow of electrons and reactant gas. Meanwhile, the method of making the electrode is one of the many studies conducted to determine the most appropriate method to use. Comparative study of the performance of proton exchange membrane fuel cell (PEMFC electrodes with different carbon powder content (vulcan XC-72 in the GDL and methods of manufacture of the electrode between casting and spraying method has been carried out. The spraying method consists of one layer and three layer of catalyst layer (CL. The content of carbon powder in the GDL as much as 3 mg cm-2 has a better performance compared to 1.5 mg cm-2 with an increase of 177.78% current density at 0.6 V. Meanwhile, the manufacture of CL with three-layer spraying method has better performance compared with one-layer spraying and casting method.

  5. High content of pyridinic- and pyrrolic-nitrogen-modified carbon nanotubes derived from blood biomass for the electrocatalysis of oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    Zheng, Jie; Guo, Chaozhong; Chen, Chunyan; Fan, Mingzhi; Gong, Jianping; Zhang, Yanfang; Zhao, Tianxin; Sun, Yuelin; Xu, Xiaofan; Li, Mengmeng; Wang, Ran; Luo, Zhongli; Chen, Changguo

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •An ORR electrocatalyst was fabricated from blood biomass and carbon nanotube. •The N-CNT catalyst exhibits good ORR activity, methanol resistance and stability. •The pyrolysis process produces high contents of pyridinic and pyrrolic N species. •The pyridinic-N group may play more important role in the active sites for ORR. -- Abstract: Here we present a facile synthetic route to design nitrogen-doped nanostructured carbon-based electrocatalyst for oxygen reduction reaction (ORR) by the copyrolysis of blood biomass from pig and carbon nanotubes (CNTs) at high temperatures. The nitrogen-doped CNTs obtained at 800 °C not only results in excellent ORR activity with four-electron transfer selectivity in alkaline medium, but also exhibits superior methanol-tolerant property and long-term stability. It is confirmed that high-temperature pyrolysis processes can facilitate to produce higher contents of pyridinic- and pyrrolic-N binding groups in electrocatalysts, contributing to the enhancement of ORR performance in terms of onset potential, half-wave potential, and limited current density. We also propose that the planar-N configuration may be the active site that is responsible for the improved ORR electrocatalytic performance. The straight-forward and cheap synthesis of the active and stable electrocatalyst makes it a promising candidate for electrochemical power sources such as fuel cells or metal-air batteries

  6. Effects of tillage on contents of organic carbon, nitrogen, water-stable aggregates and light fraction for four different long-term trials

    Science.gov (United States)

    Andruschkewitsch, R.; Geisseler, D.; Koch, H.-J.; Ludwig, B.

    2012-04-01

    Despite increasing interest in tillage techniques as a factor affecting organic carbon (Corg) dynamics and stabilization mechanisms little is known about the underlying processes. Our objectives were (i) to quantify the impact of different tillage treatments on the amount and distribution of of labile Corg pools, on the water-stable macro-aggregate (>250 µm) contents and on organic carbon (Corg) storage and (ii) to quantify the ability of soils under different tillage treatments, light fraction (LF) inputs and clay contents in macro-aggregate formation. Therefore four long-term tillage trials on loess soil in Germany with regular conventional tillage (CT, to 30 cm), mulch tillage (MT, to 10 cm), and no-tillage (NT) treatments. Samples were taken in 0-5 cm, 5-25 cm and 25-40 cm depth after 18-25 years of different tillage treatments and investigated on free and occluded LF (fLF and oLF, respectively) and on macro-aggregate contents. Furthermore an incubation experiment for the quantifcation of macro-aggregate formation was conducted. Macro-aggregates in soils from CT and NT treatments (0-5 and 5-25 cm soil depth) were destroyed and different amounts of light fraction (LF) and clay were applied. The four long-term tillage trials, differing in texture and climatic conditions, revealed consistent results in Corg storage among each other. Based on the equivalent soil mass approach (CT: 0-40, MT: 0-38, NT: 0-36 cm) the Corg stocks in the sampled profile were significantly higher for the MT treatment than for the CT and NT treatments. Significantly lower Corg, fLF, oLF, and macro-aggregate contents for the soils under CT treatment in comparison with the soils under NT and MT treatments were restricted on the top 5 cm. The correlation of the macro-aggregate content against the fLF and oLF contents suggested that the macro-aggregate content is influenced to a lesser extent directly by the physical impact of the different tillage treatments but by the contents of available

  7. Comparison of sample digestion techniques for the determination of trace and residual catalyst metal content in single-wall carbon nanotubes by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, Patricia, E-mail: patricia.grinberg@nrc.ca [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Sturgeon, Ralph E. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Diehl, Liange de O.; Bizzi, Cezar A. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil); Flores, Erico M.M. [Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil)

    2015-03-01

    A single-wall carbon nanotube material produced by laser ablation of renewable biochar in the presence of Ni and Co catalyst was characterized for residual catalyst (Co and Ni) as well as trace metal impurity content (Fe, Mo, Cr, Pb and Hg) by isotope dilution ICP-MS following sample digestion. Several matrix destruction procedures were evaluated, including a multi-step microwave-assisted acid digestion, dry ashing at 450 °C and microwave-induced combustion with oxygen. Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements. Although laborious to execute, the multi-step microwave-assisted acid digestion proved to be most reliable for recovery of the majority of the analytes, although content of Cr remained biased low for each approach, likely due to its presence as refractory carbide. - Highlights: • Determination of trace and residual catalyst metal content in Single-Wall Carbon Nanotubes by Inductively Coupled Plasma Mass Spectrometry. • Comparative study of digestion methodology combined with high precision isotope dilution ICP-MS for quantitation of elements of toxicologic relevance. • Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements.

  8. Teneur en uranium et datation U-Th des tissus osseux et dentaires fossiles de la grotte du Lazaret

    Science.gov (United States)

    Michel, Véronique; Falguères, Christophe; Yokoyama, Yuji

    1997-09-01

    Fossil bone and dental tissues from Lazaret cave and modern ones are here the subject of a comparative microscopical study. Porous tissues such as dentine and bone have retained their Haversian and Tomes canals respectively. However, cracked areas with calcite were detected, indicating a water percolation within porous tissues and an alteration of tissue in places. In addition, compact fossil enamel is particularly well preserved. These results are essential for U-Th and ESR dating application. Uranium contents, U-Th ages of two fossil mandibular tissues, two tibias and of six burnt fossil bones are presented and discussed.

  9. Predicted net efflux of radiocarbon from the ocean and increase in atmospheric radiocarbon content

    Science.gov (United States)

    Caldeira, Ken; Rau, Greg H.; Duffy, Philip B.

    Prior to changes introduced by man, production of radiocarbon (14C) in the stratosphere nearly balanced the flux of 14C from the atmosphere to the ocean and land biosphere, which in turn nearly balanced radioactive decay in these 14C reservoirs. This balance has been altered by land-use changes, fossil-fuel burning, and atmospheric nuclear detonations. Here, we use a model of the global carbon cycle to quantify these radiocarbon fluxes and make predictions about their magnitude in the future. Atmospheric nuclear detonations increased atmospheric 14C content by about 80% by the mid-1960's. Since that time, the 14C content of the atmosphere has been diminishing as this bomb radiocarbon has been entering the oceans and terrestrial biosphere. However, we predict that atmospheric 14C content will reach a minimum and start to increase within the next few years if fossil-fuel burning continues according to a “business-as-usual” scenario, even though fossil fuels are devoid of 14C. This will happen because fossil-fuel carbon diminishes the net flux of 14C from the atmosphere to the oceans and land biosphere, forcing 14C to accumulate in the atmosphere. Furthermore, the net flux of both bomb and natural 14C into the ocean are predicted to continue to slow and then, in the middle of the next century, to reverse, so that there will be a net flux of 14C from the ocean to the atmosphere. The predicted reversal of net 14C fluxes into the ocean is a further example of human impacts on the global carbon cycle.

  10. Feasibility studies of a carbon/oxygen logging tool for evaluating the CO2 content of the medium in nuclear device containment

    International Nuclear Information System (INIS)

    West, H.I. Jr.; Glasgow, J.E.

    1983-12-01

    The feasibility of using oil-well bore-hole logging techniques for assaying the carbonate content of a potential shot site has been investigated. The procedure makes use of the detection of the 4439-keV γ ray of carbon and the 6130-keV γ ray of oxygen produced by the inelastic scattering of 14-MeV neutrons in the bore-hole medium. For the needs of the containment program, a sensitivity of detection of CO 2 to less than or equal to 0.02 weight fraction must be achieved. Laboratory measurements indicate that only with considerable development effort could a tool be made that would come close to achieving this goal

  11. The original colours of fossil beetles.

    Science.gov (United States)

    McNamara, Maria E; Briggs, Derek E G; Orr, Patrick J; Noh, Heeso; Cao, Hui

    2012-03-22

    Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.

  12. Fossil energy: From laboratory to marketplace

    International Nuclear Information System (INIS)

    1992-03-01

    The purpose of this work is to provide a summary description of the role of advanced research in the overall Fossil Energy R ampersand D program successes. It presents the specific Fossil Energy advanced research products that have been adopted commercially or fed into other R ampersand D programs as part of the crosscutting enabling technology base upon which advanced systems are based

  13. Fossil Fuels, Backstop Technologies, and Imperfect Substitution

    NARCIS (Netherlands)

    van der Meijden, G.C.; Pittel, Karen; van der Ploeg, Frederick; Withagen, Cees

    2014-01-01

    This chapter studies the transition from fossil fuels to backstop technologies in a general equilibrium model in which growth is driven by research and development. The analysis generalizes the existing literature by allowing for imperfect substitution between fossil fuels and the new energy

  14. Fossil evidence of the zygomycetous fungi

    NARCIS (Netherlands)

    Krings, M.; Taylor, T.N.; Dotzler, N.

    2013-01-01

    Molecular clock data indicate that the first zygomycetous fungi occurred on Earth during the Precambrian, however, fossil evidence of these organisms has been slow to accumulate. In this paper, the fossil record of the zygomycetous fungi is compiled, with a focus on structurally preserved

  15. The Use of Ameliorant Fe3+ and Rock Phosphates in Peat Soil at Several Water Condition on the P Content of Plants Rice and Carbon Emission

    Directory of Open Access Journals (Sweden)

    Nelvia

    2009-09-01

    Full Text Available The addition of ameliorant Fe3+ and rock phosphates containing high Fe cation can reduce effect of toxic organic acids, increase peat stability through formation of complex compounds and reduce carbon emission. The research was conducted in the laboratory and green house of the Departement of Soil Science, Faculty of Agriculture, Bogor Agriculture University. Peat samples with hemic degree of decomposition were taken from Riau. Rock phosphates were taken from the rock phosphates of PT. Petrokimia Gresik, Christmas Island phosphates, and Huinan China and FeCl3.6H2O was used as the other Fe3+ source. The aims of the research were to study (a the effect of the applications of ameliorant Fe3+ and rock phosphates on the P content of plants dan (b the effect of the application ameliorant Fe3+ and the contribution of Fe cation in rock phosphates in the decrease of carbon emission. The results showed that the P content of plants rice increased 58 – 286% with the applications of ameliorant Fe3+ and rock phosphates. The estimation of carbon loss through CO2 and CH4 emissions from peats if planted continuously with rice was around 2.5, 2.2 and 2.6 Mg of C ha-1 year-1 respectively in field capacity condition, two times of field capacity condition, and 5 cm of saturated condition. The application of ameliorant Fe3+ and rock phosphates containing high Fe cation increased the stability of peats and reduced the carbon loss around 1.7 Mg of C ha-1 year-1 (64% in 5 cm of saturated condition, 1.3 Mg of C ha-1 year-1 (58% in two times of field capacity condition, and 1.0 Mg of C ha-1 year-1 (41% in field capacity condition.

  16. Penetrative trace fossils from the late Ediacaran of Mongolia: early onset of the agronomic revolution

    Science.gov (United States)

    Oji, Tatsuo; Dornbos, Stephen Q.; Yada, Keigo; Hasegawa, Hitoshi; Gonchigdorj, Sersmaa; Mochizuki, Takafumi; Takayanagi, Hideko; Iryu, Yasufumi

    2018-02-01

    The Cambrian radiation of complex animals includes a dramatic increase in the depth and intensity of bioturbation in seafloor sediment known as the `agronomic revolution'. This bioturbation transition was coupled with a shift in dominant trace fossil style from horizontal surficial traces in the late Precambrian to vertically penetrative trace fossils in the Cambrian. Here we show the existence of the first vertically penetrative trace fossils from the latest Ediacaran: dense occurrences of the U-shaped trace fossil Arenicolites from late Precambrian marine carbonates of Western Mongolia. Their Ediacaran age is established through stable carbon isotope chemostratigraphy and their occurrence stratigraphically below the first appearance of the trace fossil Treptichnus pedum. These Arenicolites are large in diameter, penetrate down to at least 4 cm into the sediment, and were presumably formed by the activity of bilaterian animals. They are preserved commonly as paired circular openings on bedding planes with maximum diameters ranging up to almost 1 cm, and as U- and J-shaped tubes in vertical sections of beds. Discovery of these complex penetrative trace fossils demonstrates that the agronomic revolution started earlier than previously considered.

  17. Supply of fossil heating and motor fuels

    International Nuclear Information System (INIS)

    Kaegi, W.; Siegrist, S.; Schaefli, M.; Eichenberger, U.

    2003-01-01

    This comprehensive study made for the Swiss Federal Office of Energy (SFOE) within the framework of the Energy Economics Fundamentals research programme examines if it can be guaranteed that Swiss industry can be supplied with fossil fuels for heating and transport purposes over the next few decades. The results of a comprehensive survey of literature on the subject are presented, with a major focus being placed on oil. The study examines both pessimistic and optimistic views and also presents an overview of fossil energy carriers and the possibilities of substituting them. Scenarios and prognoses on the availability of fossil fuels and their reserves for the future are presented. Also, new technologies for exploration and the extraction of fossil fuels are discussed, as are international interdependencies that influence supply. Market and price scenarios are presented that take account of a possible increasing scarcity of fossil fuels. The implications for industry and investment planning are examined

  18. Spatial and temporal variations of carbonate content in the beach and nearshore environments off Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Veerayya, M.

    -90%) in the foreshore regions of individual beaches whereas low CaCO sub(3) (less than 20%) in the dune and backshore areas of these beaches and adjoining nearshore environs up to 10 m isobath. The observed spatial distribution shows the occurrence of modern carbonate...

  19. Soil carbon and nitrogen content and stabilization in mid-rotation, intensively managed sweetgum and loblolly stands

    Science.gov (United States)

    Kurt H. Johnsen; Lisa J. Samuelson; Felipe G. Sanchez; Bob Eaton

    2013-01-01

    Intensive forestry has resulted in considerable increases in aboveground stand productivity including foliar and belowground biomass which are the primary sources of soil organic matter. Soil organic matter is important for the maintenance of soil physical, chemical and biological quality. Additionally, sequestering carbon (C) in soils may provide a means of mitigating...

  20. Time-dependent climate benefits of using forest residues to substitute fossil fuels

    International Nuclear Information System (INIS)

    Sathre, Roger; Gustavsson, Leif

    2011-01-01

    In this study we analyze and compare the climate impacts from the recovery, transport and combustion of forest residues (harvest slash and stumps), versus the climate impacts that would have occurred if the residues were left in the forest and fossil fuels used instead. We use cumulative radiative forcing (CRF) as an indicator of climate impacts, and we explicitly consider the temporal dynamics of atmospheric carbon dioxide and biomass decomposition. Over a 240-year period, we find that CRF is significantly reduced when forest residues are used instead of fossil fuels. The type of fossil fuel replaced is important, with coal replacement giving the greatest CRF reduction. Replacing oil and fossil gas also gives long-term CRF reduction, although CRF is positive during the first 10-25 years when these fuels are replaced. Biomass productivity is also important, with more productive forests giving greater CRF reduction per hectare. The decay rate for biomass left in the forest is found to be less significant. Fossil energy inputs for biomass recovery and transport have very little impact on CRF. -- Highlights: → Cumulative radiative forcing (CRF) can measure climate impacts of dynamic systems. → Climate impact is reduced when forest slash and stumps are used to replace fossil fuels. → Forest biofuels may cause short-term climate impact, followed by long-term climate benefit. → Forest residues should replace coal to avoid short-term climate impact. → Fossil energy used for biofuel recovery and transport has very little climate impact.

  1. A facile approach towards increasing the nitrogen-content in nitrogen-doped carbon nanotubes via halogenated catalysts

    International Nuclear Information System (INIS)

    Ombaka, L.M.; Ndungu, P.G.; Omondi, B.; McGettrick, J.D.; Davies, M.L.; Nyamori, V.O.

    2016-01-01

    Nitrogen-doped carbon nanotubes (N-CNTs) have been synthesized at 850 °C via a CVD deposition technique by use of three ferrocenyl derivative catalysts, i.e. para-CN, -CF_3 and -Cl substituted-phenyl rings. The synthesized catalysts have been characterized by NMR, IR, HR-MS and XRD. The XRD analysis of the para-CF_3 catalyst indicates that steric factors influence the X-ray structure of 1,1′-ferrocenylphenyldiacrylonitriles. Acetonitrile or pyridine was used as carbon and nitrogen sources to yield mixtures of N-CNTs and carbon spheres (CS). The N-CNTs obtained from the para-CF_3 catalysts, in pyridine, have the highest nitrogen-doping level, show a helical morphology and are less thermally stable compared with those synthesized by use of the para-CN and -Cl as catalyst. This suggests that fluorine heteroatoms enhance nitrogen-doping in N-CNTs and formation of helical-N-CNTs (H-N-CNTs). The para-CF_3 and para-Cl catalysts in acetonitrile yielded iron-filled N-CNTs, indicating that halogens promote encapsulation of iron into the cavity of N-CNT. The use of acetonitrile, as carbon and nitrogen source, with the para-CN and -Cl as catalysts also yielded a mixture of N-CNTs and carbon nanofibres (CNFs), with less abundance of CNFs in the products obtained using para-Cl catalysts. However, para-CF_3 catalyst in acetonitrile gave N-CNTs as the only shaped carbon nanomaterials. - Graphical abstract: Graphical abstract showing the synthesis of N-CNTs using halogenated-ferrocenyl derivatives as catalyst with pyridine or acetonitrile as nitrogen and carbon sources via the chemical vapour deposition technique. - Highlights: • N-CNTs were synthesized from halogenated ferrocenyl catalysts. • Halogenated catalysts promote nitrogen-doping and pyridinic nitrogen in N-CNTs. • Halogenated catalysts facilitate iron filling of N-CNTs.

  2. Hydrophilicity, pore structure and mechanical performance of CNT/PVDF materials affected by carboxyl contents in multi-walled carbon nanotubes

    Science.gov (United States)

    Zhang, Yanxia; Jiang, Ce; Tian, Run; Li, Guangfen

    2018-01-01

    Poly (vinylidene fluoride) (PVDF) membranes have been prepared by loading different type of MWCNTs-COOH as the dispersed phase via phase inversion method. The chemically functionalized MWCNTs with increasing carboxyl content were chosen for achieving a better dispersion in PVDF and altering the membrane hydrophilicity. The effect of the carboxyl content in MWCNTs on crystal structure, thermal behavior, membrane morphology, hydrophilicity, and water flux of blended membranes were investigated. Due to the addition of carbon nanotubes, various performances of the hybrid membrane had obvious changes. The most prominent was that thermal stability could be enhanced and the pore morphology was more preferable, also that the hydrophilicity were improved, further that water flux could be increased to some extent.

  3. Antelope--Fossil rebuild project

    International Nuclear Information System (INIS)

    1992-04-01

    The Columbia Power Cooperative Association (CPCA), Monument, Oregon, proposes to upgrade a 69-kV transmission line in Wasco and Wheeler Counties, Oregon, between the Antelope Substation and the Bonneville Power Administration's (BPA) Fossil Substation. The project involves rebuilding and reconductoring 23.2 miles of transmission line, including modifying it for future use at 115 kV. Related project activities will include setting new wood pole structures, removing and disposing of old structures, conductors, and insulators, and stringing new conductor, all within the existing right-of-way. No new access roads will be required. A Borrower's Environmental Report was prepared for the 1992--1993 Work Plan for Columbia Power Cooperative Association in March 1991. This report investigated cultural resources, threatened or endangered species, wetlands, and floodplains, and other environmental issues, and included correspondence with appropriate Federal, state, and local agencies. The report was submitted to the Rural Electrification Administration for their use in preparing their environmental documentation for the project

  4. [Black carbon content a